diff --git "a/llava_video/lib/python3.10/site-packages/scipy/ndimage/_morphology.py" "b/llava_video/lib/python3.10/site-packages/scipy/ndimage/_morphology.py" new file mode 100644--- /dev/null +++ "b/llava_video/lib/python3.10/site-packages/scipy/ndimage/_morphology.py" @@ -0,0 +1,2629 @@ +# Copyright (C) 2003-2005 Peter J. Verveer +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions +# are met: +# +# 1. Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# +# 2. Redistributions in binary form must reproduce the above +# copyright notice, this list of conditions and the following +# disclaimer in the documentation and/or other materials provided +# with the distribution. +# +# 3. The name of the author may not be used to endorse or promote +# products derived from this software without specific prior +# written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS +# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY +# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE +# GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, +# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING +# NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +import warnings +import operator + +import numpy as np +from . import _ni_support +from . import _nd_image +from . import _filters + +__all__ = ['iterate_structure', 'generate_binary_structure', 'binary_erosion', + 'binary_dilation', 'binary_opening', 'binary_closing', + 'binary_hit_or_miss', 'binary_propagation', 'binary_fill_holes', + 'grey_erosion', 'grey_dilation', 'grey_opening', 'grey_closing', + 'morphological_gradient', 'morphological_laplace', 'white_tophat', + 'black_tophat', 'distance_transform_bf', 'distance_transform_cdt', + 'distance_transform_edt'] + + +def _center_is_true(structure, origin): + structure = np.asarray(structure) + coor = tuple([oo + ss // 2 for ss, oo in zip(structure.shape, + origin)]) + return bool(structure[coor]) + + +def iterate_structure(structure, iterations, origin=None): + """ + Iterate a structure by dilating it with itself. + + Parameters + ---------- + structure : array_like + Structuring element (an array of bools, for example), to be dilated with + itself. + iterations : int + number of dilations performed on the structure with itself + origin : optional + If origin is None, only the iterated structure is returned. If + not, a tuple of the iterated structure and the modified origin is + returned. + + Returns + ------- + iterate_structure : ndarray of bools + A new structuring element obtained by dilating `structure` + (`iterations` - 1) times with itself. + + See Also + -------- + generate_binary_structure + + Examples + -------- + >>> from scipy import ndimage + >>> struct = ndimage.generate_binary_structure(2, 1) + >>> struct.astype(int) + array([[0, 1, 0], + [1, 1, 1], + [0, 1, 0]]) + >>> ndimage.iterate_structure(struct, 2).astype(int) + array([[0, 0, 1, 0, 0], + [0, 1, 1, 1, 0], + [1, 1, 1, 1, 1], + [0, 1, 1, 1, 0], + [0, 0, 1, 0, 0]]) + >>> ndimage.iterate_structure(struct, 3).astype(int) + array([[0, 0, 0, 1, 0, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 1, 1, 1, 1, 1, 0], + [1, 1, 1, 1, 1, 1, 1], + [0, 1, 1, 1, 1, 1, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 0, 1, 0, 0, 0]]) + + """ + structure = np.asarray(structure) + if iterations < 2: + return structure.copy() + ni = iterations - 1 + shape = [ii + ni * (ii - 1) for ii in structure.shape] + pos = [ni * (structure.shape[ii] // 2) for ii in range(len(shape))] + slc = tuple(slice(pos[ii], pos[ii] + structure.shape[ii], None) + for ii in range(len(shape))) + out = np.zeros(shape, bool) + out[slc] = structure != 0 + out = binary_dilation(out, structure, iterations=ni) + if origin is None: + return out + else: + origin = _ni_support._normalize_sequence(origin, structure.ndim) + origin = [iterations * o for o in origin] + return out, origin + + +def generate_binary_structure(rank, connectivity): + """ + Generate a binary structure for binary morphological operations. + + Parameters + ---------- + rank : int + Number of dimensions of the array to which the structuring element + will be applied, as returned by `np.ndim`. + connectivity : int + `connectivity` determines which elements of the output array belong + to the structure, i.e., are considered as neighbors of the central + element. Elements up to a squared distance of `connectivity` from + the center are considered neighbors. `connectivity` may range from 1 + (no diagonal elements are neighbors) to `rank` (all elements are + neighbors). + + Returns + ------- + output : ndarray of bools + Structuring element which may be used for binary morphological + operations, with `rank` dimensions and all dimensions equal to 3. + + See Also + -------- + iterate_structure, binary_dilation, binary_erosion + + Notes + ----- + `generate_binary_structure` can only create structuring elements with + dimensions equal to 3, i.e., minimal dimensions. For larger structuring + elements, that are useful e.g., for eroding large objects, one may either + use `iterate_structure`, or create directly custom arrays with + numpy functions such as `numpy.ones`. + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> struct = ndimage.generate_binary_structure(2, 1) + >>> struct + array([[False, True, False], + [ True, True, True], + [False, True, False]], dtype=bool) + >>> a = np.zeros((5,5)) + >>> a[2, 2] = 1 + >>> a + array([[ 0., 0., 0., 0., 0.], + [ 0., 0., 0., 0., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 0., 0., 0., 0.], + [ 0., 0., 0., 0., 0.]]) + >>> b = ndimage.binary_dilation(a, structure=struct).astype(a.dtype) + >>> b + array([[ 0., 0., 0., 0., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 1., 1., 1., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 0., 0., 0., 0.]]) + >>> ndimage.binary_dilation(b, structure=struct).astype(a.dtype) + array([[ 0., 0., 1., 0., 0.], + [ 0., 1., 1., 1., 0.], + [ 1., 1., 1., 1., 1.], + [ 0., 1., 1., 1., 0.], + [ 0., 0., 1., 0., 0.]]) + >>> struct = ndimage.generate_binary_structure(2, 2) + >>> struct + array([[ True, True, True], + [ True, True, True], + [ True, True, True]], dtype=bool) + >>> struct = ndimage.generate_binary_structure(3, 1) + >>> struct # no diagonal elements + array([[[False, False, False], + [False, True, False], + [False, False, False]], + [[False, True, False], + [ True, True, True], + [False, True, False]], + [[False, False, False], + [False, True, False], + [False, False, False]]], dtype=bool) + + """ + if connectivity < 1: + connectivity = 1 + if rank < 1: + return np.array(True, dtype=bool) + output = np.fabs(np.indices([3] * rank) - 1) + output = np.add.reduce(output, 0) + return output <= connectivity + + +def _binary_erosion(input, structure, iterations, mask, output, + border_value, origin, invert, brute_force, axes): + try: + iterations = operator.index(iterations) + except TypeError as e: + raise TypeError('iterations parameter should be an integer') from e + + input = np.asarray(input) + ndim = input.ndim + if np.iscomplexobj(input): + raise TypeError('Complex type not supported') + axes = _ni_support._check_axes(axes, input.ndim) + num_axes = len(axes) + if structure is None: + structure = generate_binary_structure(num_axes, 1) + else: + structure = np.asarray(structure, dtype=bool) + if ndim > num_axes: + structure = _filters._expand_footprint(ndim, axes, structure, + footprint_name="structure") + + if structure.ndim != input.ndim: + raise RuntimeError('structure and input must have same dimensionality') + if not structure.flags.contiguous: + structure = structure.copy() + if structure.size < 1: + raise RuntimeError('structure must not be empty') + if mask is not None: + mask = np.asarray(mask) + if mask.shape != input.shape: + raise RuntimeError('mask and input must have equal sizes') + origin = _ni_support._normalize_sequence(origin, num_axes) + origin = _filters._expand_origin(ndim, axes, origin) + cit = _center_is_true(structure, origin) + if isinstance(output, np.ndarray): + if np.iscomplexobj(output): + raise TypeError('Complex output type not supported') + else: + output = bool + output = _ni_support._get_output(output, input) + temp_needed = np.may_share_memory(input, output) + if temp_needed: + # input and output arrays cannot share memory + temp = output + output = _ni_support._get_output(output.dtype, input) + if iterations == 1: + _nd_image.binary_erosion(input, structure, mask, output, + border_value, origin, invert, cit, 0) + elif cit and not brute_force: + changed, coordinate_list = _nd_image.binary_erosion( + input, structure, mask, output, + border_value, origin, invert, cit, 1) + structure = structure[tuple([slice(None, None, -1)] * + structure.ndim)] + for ii in range(len(origin)): + origin[ii] = -origin[ii] + if not structure.shape[ii] & 1: + origin[ii] -= 1 + if mask is not None: + mask = np.asarray(mask, dtype=np.int8) + if not structure.flags.contiguous: + structure = structure.copy() + _nd_image.binary_erosion2(output, structure, mask, iterations - 1, + origin, invert, coordinate_list) + else: + tmp_in = np.empty_like(input, dtype=bool) + tmp_out = output + if iterations >= 1 and not iterations & 1: + tmp_in, tmp_out = tmp_out, tmp_in + changed = _nd_image.binary_erosion( + input, structure, mask, tmp_out, + border_value, origin, invert, cit, 0) + ii = 1 + while ii < iterations or (iterations < 1 and changed): + tmp_in, tmp_out = tmp_out, tmp_in + changed = _nd_image.binary_erosion( + tmp_in, structure, mask, tmp_out, + border_value, origin, invert, cit, 0) + ii += 1 + if temp_needed: + temp[...] = output + output = temp + return output + + +def binary_erosion(input, structure=None, iterations=1, mask=None, output=None, + border_value=0, origin=0, brute_force=False, *, axes=None): + """ + Multidimensional binary erosion with a given structuring element. + + Binary erosion is a mathematical morphology operation used for image + processing. + + Parameters + ---------- + input : array_like + Binary image to be eroded. Non-zero (True) elements form + the subset to be eroded. + structure : array_like, optional + Structuring element used for the erosion. Non-zero elements are + considered True. If no structuring element is provided, an element + is generated with a square connectivity equal to one. + iterations : int, optional + The erosion is repeated `iterations` times (one, by default). + If iterations is less than 1, the erosion is repeated until the + result does not change anymore. + mask : array_like, optional + If a mask is given, only those elements with a True value at + the corresponding mask element are modified at each iteration. + output : ndarray, optional + Array of the same shape as input, into which the output is placed. + By default, a new array is created. + border_value : int (cast to 0 or 1), optional + Value at the border in the output array. + origin : int or tuple of ints, optional + Placement of the filter, by default 0. + brute_force : boolean, optional + Memory condition: if False, only the pixels whose value was changed in + the last iteration are tracked as candidates to be updated (eroded) in + the current iteration; if True all pixels are considered as candidates + for erosion, regardless of what happened in the previous iteration. + False by default. + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + binary_erosion : ndarray of bools + Erosion of the input by the structuring element. + + See Also + -------- + grey_erosion, binary_dilation, binary_closing, binary_opening, + generate_binary_structure + + Notes + ----- + Erosion [1]_ is a mathematical morphology operation [2]_ that uses a + structuring element for shrinking the shapes in an image. The binary + erosion of an image by a structuring element is the locus of the points + where a superimposition of the structuring element centered on the point + is entirely contained in the set of non-zero elements of the image. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Erosion_%28morphology%29 + .. [2] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((7,7), dtype=int) + >>> a[1:6, 2:5] = 1 + >>> a + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.binary_erosion(a).astype(a.dtype) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 1, 0, 0, 0], + [0, 0, 0, 1, 0, 0, 0], + [0, 0, 0, 1, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> #Erosion removes objects smaller than the structure + >>> ndimage.binary_erosion(a, structure=np.ones((5,5))).astype(a.dtype) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + + """ + return _binary_erosion(input, structure, iterations, mask, + output, border_value, origin, 0, brute_force, axes) + + +def binary_dilation(input, structure=None, iterations=1, mask=None, + output=None, border_value=0, origin=0, + brute_force=False, *, axes=None): + """ + Multidimensional binary dilation with the given structuring element. + + Parameters + ---------- + input : array_like + Binary array_like to be dilated. Non-zero (True) elements form + the subset to be dilated. + structure : array_like, optional + Structuring element used for the dilation. Non-zero elements are + considered True. If no structuring element is provided an element + is generated with a square connectivity equal to one. + iterations : int, optional + The dilation is repeated `iterations` times (one, by default). + If iterations is less than 1, the dilation is repeated until the + result does not change anymore. Only an integer of iterations is + accepted. + mask : array_like, optional + If a mask is given, only those elements with a True value at + the corresponding mask element are modified at each iteration. + output : ndarray, optional + Array of the same shape as input, into which the output is placed. + By default, a new array is created. + border_value : int (cast to 0 or 1), optional + Value at the border in the output array. + origin : int or tuple of ints, optional + Placement of the filter, by default 0. + brute_force : boolean, optional + Memory condition: if False, only the pixels whose value was changed in + the last iteration are tracked as candidates to be updated (dilated) + in the current iteration; if True all pixels are considered as + candidates for dilation, regardless of what happened in the previous + iteration. False by default. + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + binary_dilation : ndarray of bools + Dilation of the input by the structuring element. + + See Also + -------- + grey_dilation, binary_erosion, binary_closing, binary_opening, + generate_binary_structure + + Notes + ----- + Dilation [1]_ is a mathematical morphology operation [2]_ that uses a + structuring element for expanding the shapes in an image. The binary + dilation of an image by a structuring element is the locus of the points + covered by the structuring element, when its center lies within the + non-zero points of the image. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Dilation_%28morphology%29 + .. [2] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((5, 5)) + >>> a[2, 2] = 1 + >>> a + array([[ 0., 0., 0., 0., 0.], + [ 0., 0., 0., 0., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 0., 0., 0., 0.], + [ 0., 0., 0., 0., 0.]]) + >>> ndimage.binary_dilation(a) + array([[False, False, False, False, False], + [False, False, True, False, False], + [False, True, True, True, False], + [False, False, True, False, False], + [False, False, False, False, False]], dtype=bool) + >>> ndimage.binary_dilation(a).astype(a.dtype) + array([[ 0., 0., 0., 0., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 1., 1., 1., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 0., 0., 0., 0.]]) + >>> # 3x3 structuring element with connectivity 1, used by default + >>> struct1 = ndimage.generate_binary_structure(2, 1) + >>> struct1 + array([[False, True, False], + [ True, True, True], + [False, True, False]], dtype=bool) + >>> # 3x3 structuring element with connectivity 2 + >>> struct2 = ndimage.generate_binary_structure(2, 2) + >>> struct2 + array([[ True, True, True], + [ True, True, True], + [ True, True, True]], dtype=bool) + >>> ndimage.binary_dilation(a, structure=struct1).astype(a.dtype) + array([[ 0., 0., 0., 0., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 1., 1., 1., 0.], + [ 0., 0., 1., 0., 0.], + [ 0., 0., 0., 0., 0.]]) + >>> ndimage.binary_dilation(a, structure=struct2).astype(a.dtype) + array([[ 0., 0., 0., 0., 0.], + [ 0., 1., 1., 1., 0.], + [ 0., 1., 1., 1., 0.], + [ 0., 1., 1., 1., 0.], + [ 0., 0., 0., 0., 0.]]) + >>> ndimage.binary_dilation(a, structure=struct1,\\ + ... iterations=2).astype(a.dtype) + array([[ 0., 0., 1., 0., 0.], + [ 0., 1., 1., 1., 0.], + [ 1., 1., 1., 1., 1.], + [ 0., 1., 1., 1., 0.], + [ 0., 0., 1., 0., 0.]]) + + """ + input = np.asarray(input) + axes = _ni_support._check_axes(axes, input.ndim) + num_axes = len(axes) + if structure is None: + structure = generate_binary_structure(num_axes, 1) + origin = _ni_support._normalize_sequence(origin, num_axes) + structure = np.asarray(structure) + structure = structure[tuple([slice(None, None, -1)] * + structure.ndim)] + for ii in range(len(origin)): + origin[ii] = -origin[ii] + if not structure.shape[ii] & 1: + origin[ii] -= 1 + + return _binary_erosion(input, structure, iterations, mask, + output, border_value, origin, 1, brute_force, axes) + + +def binary_opening(input, structure=None, iterations=1, output=None, + origin=0, mask=None, border_value=0, brute_force=False, *, + axes=None): + """ + Multidimensional binary opening with the given structuring element. + + The *opening* of an input image by a structuring element is the + *dilation* of the *erosion* of the image by the structuring element. + + Parameters + ---------- + input : array_like + Binary array_like to be opened. Non-zero (True) elements form + the subset to be opened. + structure : array_like, optional + Structuring element used for the opening. Non-zero elements are + considered True. If no structuring element is provided an element + is generated with a square connectivity equal to one (i.e., only + nearest neighbors are connected to the center, diagonally-connected + elements are not considered neighbors). + iterations : int, optional + The erosion step of the opening, then the dilation step are each + repeated `iterations` times (one, by default). If `iterations` is + less than 1, each operation is repeated until the result does + not change anymore. Only an integer of iterations is accepted. + output : ndarray, optional + Array of the same shape as input, into which the output is placed. + By default, a new array is created. + origin : int or tuple of ints, optional + Placement of the filter, by default 0. + mask : array_like, optional + If a mask is given, only those elements with a True value at + the corresponding mask element are modified at each iteration. + + .. versionadded:: 1.1.0 + border_value : int (cast to 0 or 1), optional + Value at the border in the output array. + + .. versionadded:: 1.1.0 + brute_force : boolean, optional + Memory condition: if False, only the pixels whose value was changed in + the last iteration are tracked as candidates to be updated in the + current iteration; if true all pixels are considered as candidates for + update, regardless of what happened in the previous iteration. + False by default. + + .. versionadded:: 1.1.0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + binary_opening : ndarray of bools + Opening of the input by the structuring element. + + See Also + -------- + grey_opening, binary_closing, binary_erosion, binary_dilation, + generate_binary_structure + + Notes + ----- + *Opening* [1]_ is a mathematical morphology operation [2]_ that + consists in the succession of an erosion and a dilation of the + input with the same structuring element. Opening, therefore, removes + objects smaller than the structuring element. + + Together with *closing* (`binary_closing`), opening can be used for + noise removal. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Opening_%28morphology%29 + .. [2] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((5,5), dtype=int) + >>> a[1:4, 1:4] = 1; a[4, 4] = 1 + >>> a + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 1]]) + >>> # Opening removes small objects + >>> ndimage.binary_opening(a, structure=np.ones((3,3))).astype(int) + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 0]]) + >>> # Opening can also smooth corners + >>> ndimage.binary_opening(a).astype(int) + array([[0, 0, 0, 0, 0], + [0, 0, 1, 0, 0], + [0, 1, 1, 1, 0], + [0, 0, 1, 0, 0], + [0, 0, 0, 0, 0]]) + >>> # Opening is the dilation of the erosion of the input + >>> ndimage.binary_erosion(a).astype(int) + array([[0, 0, 0, 0, 0], + [0, 0, 0, 0, 0], + [0, 0, 1, 0, 0], + [0, 0, 0, 0, 0], + [0, 0, 0, 0, 0]]) + >>> ndimage.binary_dilation(ndimage.binary_erosion(a)).astype(int) + array([[0, 0, 0, 0, 0], + [0, 0, 1, 0, 0], + [0, 1, 1, 1, 0], + [0, 0, 1, 0, 0], + [0, 0, 0, 0, 0]]) + + """ + input = np.asarray(input) + axes = _ni_support._check_axes(axes, input.ndim) + num_axes = len(axes) + if structure is None: + structure = generate_binary_structure(num_axes, 1) + + tmp = binary_erosion(input, structure, iterations, mask, None, + border_value, origin, brute_force, axes=axes) + return binary_dilation(tmp, structure, iterations, mask, output, + border_value, origin, brute_force, axes=axes) + + +def binary_closing(input, structure=None, iterations=1, output=None, + origin=0, mask=None, border_value=0, brute_force=False, *, + axes=None): + """ + Multidimensional binary closing with the given structuring element. + + The *closing* of an input image by a structuring element is the + *erosion* of the *dilation* of the image by the structuring element. + + Parameters + ---------- + input : array_like + Binary array_like to be closed. Non-zero (True) elements form + the subset to be closed. + structure : array_like, optional + Structuring element used for the closing. Non-zero elements are + considered True. If no structuring element is provided an element + is generated with a square connectivity equal to one (i.e., only + nearest neighbors are connected to the center, diagonally-connected + elements are not considered neighbors). + iterations : int, optional + The dilation step of the closing, then the erosion step are each + repeated `iterations` times (one, by default). If iterations is + less than 1, each operations is repeated until the result does + not change anymore. Only an integer of iterations is accepted. + output : ndarray, optional + Array of the same shape as input, into which the output is placed. + By default, a new array is created. + origin : int or tuple of ints, optional + Placement of the filter, by default 0. + mask : array_like, optional + If a mask is given, only those elements with a True value at + the corresponding mask element are modified at each iteration. + + .. versionadded:: 1.1.0 + border_value : int (cast to 0 or 1), optional + Value at the border in the output array. + + .. versionadded:: 1.1.0 + brute_force : boolean, optional + Memory condition: if False, only the pixels whose value was changed in + the last iteration are tracked as candidates to be updated in the + current iteration; if true al pixels are considered as candidates for + update, regardless of what happened in the previous iteration. + False by default. + + .. versionadded:: 1.1.0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + binary_closing : ndarray of bools + Closing of the input by the structuring element. + + See Also + -------- + grey_closing, binary_opening, binary_dilation, binary_erosion, + generate_binary_structure + + Notes + ----- + *Closing* [1]_ is a mathematical morphology operation [2]_ that + consists in the succession of a dilation and an erosion of the + input with the same structuring element. Closing therefore fills + holes smaller than the structuring element. + + Together with *opening* (`binary_opening`), closing can be used for + noise removal. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Closing_%28morphology%29 + .. [2] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((5,5), dtype=int) + >>> a[1:-1, 1:-1] = 1; a[2,2] = 0 + >>> a + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 0, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 0]]) + >>> # Closing removes small holes + >>> ndimage.binary_closing(a).astype(int) + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 0]]) + >>> # Closing is the erosion of the dilation of the input + >>> ndimage.binary_dilation(a).astype(int) + array([[0, 1, 1, 1, 0], + [1, 1, 1, 1, 1], + [1, 1, 1, 1, 1], + [1, 1, 1, 1, 1], + [0, 1, 1, 1, 0]]) + >>> ndimage.binary_erosion(ndimage.binary_dilation(a)).astype(int) + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 0]]) + + + >>> a = np.zeros((7,7), dtype=int) + >>> a[1:6, 2:5] = 1; a[1:3,3] = 0 + >>> a + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 0, 1, 0, 0], + [0, 0, 1, 0, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> # In addition to removing holes, closing can also + >>> # coarsen boundaries with fine hollows. + >>> ndimage.binary_closing(a).astype(int) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 0, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.binary_closing(a, structure=np.ones((2,2))).astype(int) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + + """ + input = np.asarray(input) + axes = _ni_support._check_axes(axes, input.ndim) + num_axes = len(axes) + if structure is None: + structure = generate_binary_structure(num_axes, 1) + + tmp = binary_dilation(input, structure, iterations, mask, None, + border_value, origin, brute_force, axes=axes) + return binary_erosion(tmp, structure, iterations, mask, output, + border_value, origin, brute_force, axes=axes) + + +def binary_hit_or_miss(input, structure1=None, structure2=None, + output=None, origin1=0, origin2=None, *, axes=None): + """ + Multidimensional binary hit-or-miss transform. + + The hit-or-miss transform finds the locations of a given pattern + inside the input image. + + Parameters + ---------- + input : array_like (cast to booleans) + Binary image where a pattern is to be detected. + structure1 : array_like (cast to booleans), optional + Part of the structuring element to be fitted to the foreground + (non-zero elements) of `input`. If no value is provided, a + structure of square connectivity 1 is chosen. + structure2 : array_like (cast to booleans), optional + Second part of the structuring element that has to miss completely + the foreground. If no value is provided, the complementary of + `structure1` is taken. + output : ndarray, optional + Array of the same shape as input, into which the output is placed. + By default, a new array is created. + origin1 : int or tuple of ints, optional + Placement of the first part of the structuring element `structure1`, + by default 0 for a centered structure. + origin2 : int or tuple of ints, optional + Placement of the second part of the structuring element `structure2`, + by default 0 for a centered structure. If a value is provided for + `origin1` and not for `origin2`, then `origin2` is set to `origin1`. + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If `origin1` or `origin2` tuples are provided, their + length must match the number of axes. + + Returns + ------- + binary_hit_or_miss : ndarray + Hit-or-miss transform of `input` with the given structuring + element (`structure1`, `structure2`). + + See Also + -------- + binary_erosion + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Hit-or-miss_transform + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((7,7), dtype=int) + >>> a[1, 1] = 1; a[2:4, 2:4] = 1; a[4:6, 4:6] = 1 + >>> a + array([[0, 0, 0, 0, 0, 0, 0], + [0, 1, 0, 0, 0, 0, 0], + [0, 0, 1, 1, 0, 0, 0], + [0, 0, 1, 1, 0, 0, 0], + [0, 0, 0, 0, 1, 1, 0], + [0, 0, 0, 0, 1, 1, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> structure1 = np.array([[1, 0, 0], [0, 1, 1], [0, 1, 1]]) + >>> structure1 + array([[1, 0, 0], + [0, 1, 1], + [0, 1, 1]]) + >>> # Find the matches of structure1 in the array a + >>> ndimage.binary_hit_or_miss(a, structure1=structure1).astype(int) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 1, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> # Change the origin of the filter + >>> # origin1=1 is equivalent to origin1=(1,1) here + >>> ndimage.binary_hit_or_miss(a, structure1=structure1,\\ + ... origin1=1).astype(int) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 1, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 1, 0], + [0, 0, 0, 0, 0, 0, 0]]) + + """ + input = np.asarray(input) + axes = _ni_support._check_axes(axes, input.ndim) + num_axes = len(axes) + if structure1 is None: + structure1 = generate_binary_structure(num_axes, 1) + else: + structure1 = np.asarray(structure1) + if structure2 is None: + structure2 = np.logical_not(structure1) + origin1 = _ni_support._normalize_sequence(origin1, num_axes) + if origin2 is None: + origin2 = origin1 + else: + origin2 = _ni_support._normalize_sequence(origin2, num_axes) + + tmp1 = _binary_erosion(input, structure1, 1, None, None, 0, origin1, + 0, False, axes) + inplace = isinstance(output, np.ndarray) + result = _binary_erosion(input, structure2, 1, None, output, 0, + origin2, 1, False, axes) + if inplace: + np.logical_not(output, output) + np.logical_and(tmp1, output, output) + else: + np.logical_not(result, result) + return np.logical_and(tmp1, result) + + +def binary_propagation(input, structure=None, mask=None, + output=None, border_value=0, origin=0, *, axes=None): + """ + Multidimensional binary propagation with the given structuring element. + + Parameters + ---------- + input : array_like + Binary image to be propagated inside `mask`. + structure : array_like, optional + Structuring element used in the successive dilations. The output + may depend on the structuring element, especially if `mask` has + several connex components. If no structuring element is + provided, an element is generated with a squared connectivity equal + to one. + mask : array_like, optional + Binary mask defining the region into which `input` is allowed to + propagate. + output : ndarray, optional + Array of the same shape as input, into which the output is placed. + By default, a new array is created. + border_value : int (cast to 0 or 1), optional + Value at the border in the output array. + origin : int or tuple of ints, optional + Placement of the filter, by default 0. + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + binary_propagation : ndarray + Binary propagation of `input` inside `mask`. + + Notes + ----- + This function is functionally equivalent to calling binary_dilation + with the number of iterations less than one: iterative dilation until + the result does not change anymore. + + The succession of an erosion and propagation inside the original image + can be used instead of an *opening* for deleting small objects while + keeping the contours of larger objects untouched. + + References + ---------- + .. [1] http://cmm.ensmp.fr/~serra/cours/pdf/en/ch6en.pdf, slide 15. + .. [2] I.T. Young, J.J. Gerbrands, and L.J. van Vliet, "Fundamentals of + image processing", 1998 + ftp://qiftp.tudelft.nl/DIPimage/docs/FIP2.3.pdf + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> input = np.zeros((8, 8), dtype=int) + >>> input[2, 2] = 1 + >>> mask = np.zeros((8, 8), dtype=int) + >>> mask[1:4, 1:4] = mask[4, 4] = mask[6:8, 6:8] = 1 + >>> input + array([[0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0]]) + >>> mask + array([[0, 0, 0, 0, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 0, 0, 0, 1, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 1, 1], + [0, 0, 0, 0, 0, 0, 1, 1]]) + >>> ndimage.binary_propagation(input, mask=mask).astype(int) + array([[0, 0, 0, 0, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.binary_propagation(input, mask=mask,\\ + ... structure=np.ones((3,3))).astype(int) + array([[0, 0, 0, 0, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 1, 1, 1, 0, 0, 0, 0], + [0, 0, 0, 0, 1, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0, 0]]) + + >>> # Comparison between opening and erosion+propagation + >>> a = np.zeros((6,6), dtype=int) + >>> a[2:5, 2:5] = 1; a[0, 0] = 1; a[5, 5] = 1 + >>> a + array([[1, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0], + [0, 0, 1, 1, 1, 0], + [0, 0, 1, 1, 1, 0], + [0, 0, 1, 1, 1, 0], + [0, 0, 0, 0, 0, 1]]) + >>> ndimage.binary_opening(a).astype(int) + array([[0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0], + [0, 0, 0, 1, 0, 0], + [0, 0, 1, 1, 1, 0], + [0, 0, 0, 1, 0, 0], + [0, 0, 0, 0, 0, 0]]) + >>> b = ndimage.binary_erosion(a) + >>> b.astype(int) + array([[0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0], + [0, 0, 0, 1, 0, 0], + [0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0]]) + >>> ndimage.binary_propagation(b, mask=a).astype(int) + array([[0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0], + [0, 0, 1, 1, 1, 0], + [0, 0, 1, 1, 1, 0], + [0, 0, 1, 1, 1, 0], + [0, 0, 0, 0, 0, 0]]) + + """ + return binary_dilation(input, structure, -1, mask, output, + border_value, origin, axes=axes) + + +def binary_fill_holes(input, structure=None, output=None, origin=0, *, + axes=None): + """ + Fill the holes in binary objects. + + + Parameters + ---------- + input : array_like + N-D binary array with holes to be filled + structure : array_like, optional + Structuring element used in the computation; large-size elements + make computations faster but may miss holes separated from the + background by thin regions. The default element (with a square + connectivity equal to one) yields the intuitive result where all + holes in the input have been filled. + output : ndarray, optional + Array of the same shape as input, into which the output is placed. + By default, a new array is created. + origin : int, tuple of ints, optional + Position of the structuring element. + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + out : ndarray + Transformation of the initial image `input` where holes have been + filled. + + See Also + -------- + binary_dilation, binary_propagation, label + + Notes + ----- + The algorithm used in this function consists in invading the complementary + of the shapes in `input` from the outer boundary of the image, + using binary dilations. Holes are not connected to the boundary and are + therefore not invaded. The result is the complementary subset of the + invaded region. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Mathematical_morphology + + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((5, 5), dtype=int) + >>> a[1:4, 1:4] = 1 + >>> a[2,2] = 0 + >>> a + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 0, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 0]]) + >>> ndimage.binary_fill_holes(a).astype(int) + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 0]]) + >>> # Too big structuring element + >>> ndimage.binary_fill_holes(a, structure=np.ones((5,5))).astype(int) + array([[0, 0, 0, 0, 0], + [0, 1, 1, 1, 0], + [0, 1, 0, 1, 0], + [0, 1, 1, 1, 0], + [0, 0, 0, 0, 0]]) + + """ + input = np.asarray(input) + mask = np.logical_not(input) + tmp = np.zeros(mask.shape, bool) + inplace = isinstance(output, np.ndarray) + if inplace: + binary_dilation(tmp, structure, -1, mask, output, 1, origin, axes=axes) + np.logical_not(output, output) + else: + output = binary_dilation(tmp, structure, -1, mask, None, 1, + origin, axes=axes) + np.logical_not(output, output) + return output + + +def grey_erosion(input, size=None, footprint=None, structure=None, + output=None, mode="reflect", cval=0.0, origin=0, *, + axes=None): + """ + Calculate a greyscale erosion, using either a structuring element, + or a footprint corresponding to a flat structuring element. + + Grayscale erosion is a mathematical morphology operation. For the + simple case of a full and flat structuring element, it can be viewed + as a minimum filter over a sliding window. + + Parameters + ---------- + input : array_like + Array over which the grayscale erosion is to be computed. + size : tuple of ints + Shape of a flat and full structuring element used for the grayscale + erosion. Optional if `footprint` or `structure` is provided. + footprint : array of ints, optional + Positions of non-infinite elements of a flat structuring element + used for the grayscale erosion. Non-zero values give the set of + neighbors of the center over which the minimum is chosen. + structure : array of ints, optional + Structuring element used for the grayscale erosion. `structure` + may be a non-flat structuring element. The `structure` array applies a + subtractive offset for each pixel in the neighborhood. + output : array, optional + An array used for storing the output of the erosion may be provided. + mode : {'reflect','constant','nearest','mirror', 'wrap'}, optional + The `mode` parameter determines how the array borders are + handled, where `cval` is the value when mode is equal to + 'constant'. Default is 'reflect' + cval : scalar, optional + Value to fill past edges of input if `mode` is 'constant'. Default + is 0.0. + origin : scalar, optional + The `origin` parameter controls the placement of the filter. + Default 0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + output : ndarray + Grayscale erosion of `input`. + + See Also + -------- + binary_erosion, grey_dilation, grey_opening, grey_closing + generate_binary_structure, minimum_filter + + Notes + ----- + The grayscale erosion of an image input by a structuring element s defined + over a domain E is given by: + + (input+s)(x) = min {input(y) - s(x-y), for y in E} + + In particular, for structuring elements defined as + s(y) = 0 for y in E, the grayscale erosion computes the minimum of the + input image inside a sliding window defined by E. + + Grayscale erosion [1]_ is a *mathematical morphology* operation [2]_. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Erosion_%28morphology%29 + .. [2] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((7,7), dtype=int) + >>> a[1:6, 1:6] = 3 + >>> a[4,4] = 2; a[2,3] = 1 + >>> a + array([[0, 0, 0, 0, 0, 0, 0], + [0, 3, 3, 3, 3, 3, 0], + [0, 3, 3, 1, 3, 3, 0], + [0, 3, 3, 3, 3, 3, 0], + [0, 3, 3, 3, 2, 3, 0], + [0, 3, 3, 3, 3, 3, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.grey_erosion(a, size=(3,3)) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 3, 2, 2, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> footprint = ndimage.generate_binary_structure(2, 1) + >>> footprint + array([[False, True, False], + [ True, True, True], + [False, True, False]], dtype=bool) + >>> # Diagonally-connected elements are not considered neighbors + >>> ndimage.grey_erosion(a, footprint=footprint) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 3, 1, 2, 0, 0], + [0, 0, 3, 2, 2, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + + """ + if size is None and footprint is None and structure is None: + raise ValueError("size, footprint, or structure must be specified") + + return _filters._min_or_max_filter(input, size, footprint, structure, + output, mode, cval, origin, 1, + axes=axes) + + +def grey_dilation(input, size=None, footprint=None, structure=None, + output=None, mode="reflect", cval=0.0, origin=0, *, + axes=None): + """ + Calculate a greyscale dilation, using either a structuring element, + or a footprint corresponding to a flat structuring element. + + Grayscale dilation is a mathematical morphology operation. For the + simple case of a full and flat structuring element, it can be viewed + as a maximum filter over a sliding window. + + Parameters + ---------- + input : array_like + Array over which the grayscale dilation is to be computed. + size : tuple of ints + Shape of a flat and full structuring element used for the grayscale + dilation. Optional if `footprint` or `structure` is provided. + footprint : array of ints, optional + Positions of non-infinite elements of a flat structuring element + used for the grayscale dilation. Non-zero values give the set of + neighbors of the center over which the maximum is chosen. + structure : array of ints, optional + Structuring element used for the grayscale dilation. `structure` + may be a non-flat structuring element. The `structure` array applies an + additive offset for each pixel in the neighborhood. + output : array, optional + An array used for storing the output of the dilation may be provided. + mode : {'reflect','constant','nearest','mirror', 'wrap'}, optional + The `mode` parameter determines how the array borders are + handled, where `cval` is the value when mode is equal to + 'constant'. Default is 'reflect' + cval : scalar, optional + Value to fill past edges of input if `mode` is 'constant'. Default + is 0.0. + origin : scalar, optional + The `origin` parameter controls the placement of the filter. + Default 0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + grey_dilation : ndarray + Grayscale dilation of `input`. + + See Also + -------- + binary_dilation, grey_erosion, grey_closing, grey_opening + generate_binary_structure, maximum_filter + + Notes + ----- + The grayscale dilation of an image input by a structuring element s defined + over a domain E is given by: + + (input+s)(x) = max {input(y) + s(x-y), for y in E} + + In particular, for structuring elements defined as + s(y) = 0 for y in E, the grayscale dilation computes the maximum of the + input image inside a sliding window defined by E. + + Grayscale dilation [1]_ is a *mathematical morphology* operation [2]_. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Dilation_%28morphology%29 + .. [2] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((7,7), dtype=int) + >>> a[2:5, 2:5] = 1 + >>> a[4,4] = 2; a[2,3] = 3 + >>> a + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 3, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 2, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.grey_dilation(a, size=(3,3)) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 1, 3, 3, 3, 1, 0], + [0, 1, 3, 3, 3, 1, 0], + [0, 1, 3, 3, 3, 2, 0], + [0, 1, 1, 2, 2, 2, 0], + [0, 1, 1, 2, 2, 2, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.grey_dilation(a, footprint=np.ones((3,3))) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 1, 3, 3, 3, 1, 0], + [0, 1, 3, 3, 3, 1, 0], + [0, 1, 3, 3, 3, 2, 0], + [0, 1, 1, 2, 2, 2, 0], + [0, 1, 1, 2, 2, 2, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> s = ndimage.generate_binary_structure(2,1) + >>> s + array([[False, True, False], + [ True, True, True], + [False, True, False]], dtype=bool) + >>> ndimage.grey_dilation(a, footprint=s) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 3, 1, 0, 0], + [0, 1, 3, 3, 3, 1, 0], + [0, 1, 1, 3, 2, 1, 0], + [0, 1, 1, 2, 2, 2, 0], + [0, 0, 1, 1, 2, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.grey_dilation(a, size=(3,3), structure=np.ones((3,3))) + array([[1, 1, 1, 1, 1, 1, 1], + [1, 2, 4, 4, 4, 2, 1], + [1, 2, 4, 4, 4, 2, 1], + [1, 2, 4, 4, 4, 3, 1], + [1, 2, 2, 3, 3, 3, 1], + [1, 2, 2, 3, 3, 3, 1], + [1, 1, 1, 1, 1, 1, 1]]) + + """ + if size is None and footprint is None and structure is None: + raise ValueError("size, footprint, or structure must be specified") + if structure is not None: + structure = np.asarray(structure) + structure = structure[tuple([slice(None, None, -1)] * + structure.ndim)] + if footprint is not None: + footprint = np.asarray(footprint) + footprint = footprint[tuple([slice(None, None, -1)] * + footprint.ndim)] + + input = np.asarray(input) + axes = _ni_support._check_axes(axes, input.ndim) + origin = _ni_support._normalize_sequence(origin, len(axes)) + for ii in range(len(origin)): + origin[ii] = -origin[ii] + if footprint is not None: + sz = footprint.shape[ii] + elif structure is not None: + sz = structure.shape[ii] + elif np.isscalar(size): + sz = size + else: + sz = size[ii] + if not sz & 1: + origin[ii] -= 1 + + return _filters._min_or_max_filter(input, size, footprint, structure, + output, mode, cval, origin, 0, + axes=axes) + + +def grey_opening(input, size=None, footprint=None, structure=None, + output=None, mode="reflect", cval=0.0, origin=0, *, + axes=None): + """ + Multidimensional grayscale opening. + + A grayscale opening consists in the succession of a grayscale erosion, + and a grayscale dilation. + + Parameters + ---------- + input : array_like + Array over which the grayscale opening is to be computed. + size : tuple of ints + Shape of a flat and full structuring element used for the grayscale + opening. Optional if `footprint` or `structure` is provided. + footprint : array of ints, optional + Positions of non-infinite elements of a flat structuring element + used for the grayscale opening. + structure : array of ints, optional + Structuring element used for the grayscale opening. `structure` + may be a non-flat structuring element. The `structure` array applies + offsets to the pixels in a neighborhood (the offset is additive during + dilation and subtractive during erosion). + output : array, optional + An array used for storing the output of the opening may be provided. + mode : {'reflect', 'constant', 'nearest', 'mirror', 'wrap'}, optional + The `mode` parameter determines how the array borders are + handled, where `cval` is the value when mode is equal to + 'constant'. Default is 'reflect' + cval : scalar, optional + Value to fill past edges of input if `mode` is 'constant'. Default + is 0.0. + origin : scalar, optional + The `origin` parameter controls the placement of the filter. + Default 0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + grey_opening : ndarray + Result of the grayscale opening of `input` with `structure`. + + See Also + -------- + binary_opening, grey_dilation, grey_erosion, grey_closing + generate_binary_structure + + Notes + ----- + The action of a grayscale opening with a flat structuring element amounts + to smoothen high local maxima, whereas binary opening erases small objects. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.arange(36).reshape((6,6)) + >>> a[3, 3] = 50 + >>> a + array([[ 0, 1, 2, 3, 4, 5], + [ 6, 7, 8, 9, 10, 11], + [12, 13, 14, 15, 16, 17], + [18, 19, 20, 50, 22, 23], + [24, 25, 26, 27, 28, 29], + [30, 31, 32, 33, 34, 35]]) + >>> ndimage.grey_opening(a, size=(3,3)) + array([[ 0, 1, 2, 3, 4, 4], + [ 6, 7, 8, 9, 10, 10], + [12, 13, 14, 15, 16, 16], + [18, 19, 20, 22, 22, 22], + [24, 25, 26, 27, 28, 28], + [24, 25, 26, 27, 28, 28]]) + >>> # Note that the local maximum a[3,3] has disappeared + + """ + if (size is not None) and (footprint is not None): + warnings.warn("ignoring size because footprint is set", + UserWarning, stacklevel=2) + tmp = grey_erosion(input, size, footprint, structure, None, mode, + cval, origin, axes=axes) + return grey_dilation(tmp, size, footprint, structure, output, mode, + cval, origin, axes=axes) + + +def grey_closing(input, size=None, footprint=None, structure=None, + output=None, mode="reflect", cval=0.0, origin=0, *, + axes=None): + """ + Multidimensional grayscale closing. + + A grayscale closing consists in the succession of a grayscale dilation, + and a grayscale erosion. + + Parameters + ---------- + input : array_like + Array over which the grayscale closing is to be computed. + size : tuple of ints + Shape of a flat and full structuring element used for the grayscale + closing. Optional if `footprint` or `structure` is provided. + footprint : array of ints, optional + Positions of non-infinite elements of a flat structuring element + used for the grayscale closing. + structure : array of ints, optional + Structuring element used for the grayscale closing. `structure` + may be a non-flat structuring element. The `structure` array applies + offsets to the pixels in a neighborhood (the offset is additive during + dilation and subtractive during erosion) + output : array, optional + An array used for storing the output of the closing may be provided. + mode : {'reflect', 'constant', 'nearest', 'mirror', 'wrap'}, optional + The `mode` parameter determines how the array borders are + handled, where `cval` is the value when mode is equal to + 'constant'. Default is 'reflect' + cval : scalar, optional + Value to fill past edges of input if `mode` is 'constant'. Default + is 0.0. + origin : scalar, optional + The `origin` parameter controls the placement of the filter. + Default 0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + grey_closing : ndarray + Result of the grayscale closing of `input` with `structure`. + + See Also + -------- + binary_closing, grey_dilation, grey_erosion, grey_opening, + generate_binary_structure + + Notes + ----- + The action of a grayscale closing with a flat structuring element amounts + to smoothen deep local minima, whereas binary closing fills small holes. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.arange(36).reshape((6,6)) + >>> a[3,3] = 0 + >>> a + array([[ 0, 1, 2, 3, 4, 5], + [ 6, 7, 8, 9, 10, 11], + [12, 13, 14, 15, 16, 17], + [18, 19, 20, 0, 22, 23], + [24, 25, 26, 27, 28, 29], + [30, 31, 32, 33, 34, 35]]) + >>> ndimage.grey_closing(a, size=(3,3)) + array([[ 7, 7, 8, 9, 10, 11], + [ 7, 7, 8, 9, 10, 11], + [13, 13, 14, 15, 16, 17], + [19, 19, 20, 20, 22, 23], + [25, 25, 26, 27, 28, 29], + [31, 31, 32, 33, 34, 35]]) + >>> # Note that the local minimum a[3,3] has disappeared + + """ + if (size is not None) and (footprint is not None): + warnings.warn("ignoring size because footprint is set", + UserWarning, stacklevel=2) + tmp = grey_dilation(input, size, footprint, structure, None, mode, + cval, origin, axes=axes) + return grey_erosion(tmp, size, footprint, structure, output, mode, + cval, origin, axes=axes) + + +def morphological_gradient(input, size=None, footprint=None, structure=None, + output=None, mode="reflect", cval=0.0, origin=0, *, + axes=None): + """ + Multidimensional morphological gradient. + + The morphological gradient is calculated as the difference between a + dilation and an erosion of the input with a given structuring element. + + Parameters + ---------- + input : array_like + Array over which to compute the morphlogical gradient. + size : tuple of ints + Shape of a flat and full structuring element used for the mathematical + morphology operations. Optional if `footprint` or `structure` is + provided. A larger `size` yields a more blurred gradient. + footprint : array of ints, optional + Positions of non-infinite elements of a flat structuring element + used for the morphology operations. Larger footprints + give a more blurred morphological gradient. + structure : array of ints, optional + Structuring element used for the morphology operations. `structure` may + be a non-flat structuring element. The `structure` array applies + offsets to the pixels in a neighborhood (the offset is additive during + dilation and subtractive during erosion) + output : array, optional + An array used for storing the output of the morphological gradient + may be provided. + mode : {'reflect', 'constant', 'nearest', 'mirror', 'wrap'}, optional + The `mode` parameter determines how the array borders are + handled, where `cval` is the value when mode is equal to + 'constant'. Default is 'reflect' + cval : scalar, optional + Value to fill past edges of input if `mode` is 'constant'. Default + is 0.0. + origin : scalar, optional + The `origin` parameter controls the placement of the filter. + Default 0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + morphological_gradient : ndarray + Morphological gradient of `input`. + + See Also + -------- + grey_dilation, grey_erosion, gaussian_gradient_magnitude + + Notes + ----- + For a flat structuring element, the morphological gradient + computed at a given point corresponds to the maximal difference + between elements of the input among the elements covered by the + structuring element centered on the point. + + References + ---------- + .. [1] https://en.wikipedia.org/wiki/Mathematical_morphology + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.zeros((7,7), dtype=int) + >>> a[2:5, 2:5] = 1 + >>> ndimage.morphological_gradient(a, size=(3,3)) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 1, 1, 0, 1, 1, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> # The morphological gradient is computed as the difference + >>> # between a dilation and an erosion + >>> ndimage.grey_dilation(a, size=(3,3)) -\\ + ... ndimage.grey_erosion(a, size=(3,3)) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 1, 1, 0, 1, 1, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 1, 1, 1, 1, 1, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> a = np.zeros((7,7), dtype=int) + >>> a[2:5, 2:5] = 1 + >>> a[4,4] = 2; a[2,3] = 3 + >>> a + array([[0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 1, 3, 1, 0, 0], + [0, 0, 1, 1, 1, 0, 0], + [0, 0, 1, 1, 2, 0, 0], + [0, 0, 0, 0, 0, 0, 0], + [0, 0, 0, 0, 0, 0, 0]]) + >>> ndimage.morphological_gradient(a, size=(3,3)) + array([[0, 0, 0, 0, 0, 0, 0], + [0, 1, 3, 3, 3, 1, 0], + [0, 1, 3, 3, 3, 1, 0], + [0, 1, 3, 2, 3, 2, 0], + [0, 1, 1, 2, 2, 2, 0], + [0, 1, 1, 2, 2, 2, 0], + [0, 0, 0, 0, 0, 0, 0]]) + + """ + tmp = grey_dilation(input, size, footprint, structure, None, mode, + cval, origin, axes=axes) + if isinstance(output, np.ndarray): + grey_erosion(input, size, footprint, structure, output, mode, + cval, origin, axes=axes) + return np.subtract(tmp, output, output) + else: + return (tmp - grey_erosion(input, size, footprint, structure, + None, mode, cval, origin, axes=axes)) + + +def morphological_laplace(input, size=None, footprint=None, structure=None, + output=None, mode="reflect", cval=0.0, origin=0, *, + axes=None): + """ + Multidimensional morphological laplace. + + Parameters + ---------- + input : array_like + Input. + size : tuple of ints + Shape of a flat and full structuring element used for the mathematical + morphology operations. Optional if `footprint` or `structure` is + provided. + footprint : array of ints, optional + Positions of non-infinite elements of a flat structuring element + used for the morphology operations. + structure : array of ints, optional + Structuring element used for the morphology operations. `structure` may + be a non-flat structuring element. The `structure` array applies + offsets to the pixels in a neighborhood (the offset is additive during + dilation and subtractive during erosion) + output : ndarray, optional + An output array can optionally be provided. + mode : {'reflect','constant','nearest','mirror', 'wrap'}, optional + The mode parameter determines how the array borders are handled. + For 'constant' mode, values beyond borders are set to be `cval`. + Default is 'reflect'. + cval : scalar, optional + Value to fill past edges of input if mode is 'constant'. + Default is 0.0 + origin : origin, optional + The origin parameter controls the placement of the filter. + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + morphological_laplace : ndarray + Output + + """ + tmp1 = grey_dilation(input, size, footprint, structure, None, mode, + cval, origin, axes=axes) + if isinstance(output, np.ndarray): + grey_erosion(input, size, footprint, structure, output, mode, + cval, origin, axes=axes) + np.add(tmp1, output, output) + np.subtract(output, input, output) + return np.subtract(output, input, output) + else: + tmp2 = grey_erosion(input, size, footprint, structure, None, mode, + cval, origin, axes=axes) + np.add(tmp1, tmp2, tmp2) + np.subtract(tmp2, input, tmp2) + np.subtract(tmp2, input, tmp2) + return tmp2 + + +def white_tophat(input, size=None, footprint=None, structure=None, + output=None, mode="reflect", cval=0.0, origin=0, *, + axes=None): + """ + Multidimensional white tophat filter. + + Parameters + ---------- + input : array_like + Input. + size : tuple of ints + Shape of a flat and full structuring element used for the filter. + Optional if `footprint` or `structure` is provided. + footprint : array of ints, optional + Positions of elements of a flat structuring element + used for the white tophat filter. + structure : array of ints, optional + Structuring element used for the filter. `structure` may be a non-flat + structuring element. The `structure` array applies offsets to the + pixels in a neighborhood (the offset is additive during dilation and + subtractive during erosion) + output : array, optional + An array used for storing the output of the filter may be provided. + mode : {'reflect', 'constant', 'nearest', 'mirror', 'wrap'}, optional + The `mode` parameter determines how the array borders are + handled, where `cval` is the value when mode is equal to + 'constant'. Default is 'reflect' + cval : scalar, optional + Value to fill past edges of input if `mode` is 'constant'. + Default is 0.0. + origin : scalar, optional + The `origin` parameter controls the placement of the filter. + Default is 0. + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + output : ndarray + Result of the filter of `input` with `structure`. + + See Also + -------- + black_tophat + + Examples + -------- + Subtract gray background from a bright peak. + + >>> from scipy.ndimage import generate_binary_structure, white_tophat + >>> import numpy as np + >>> square = generate_binary_structure(rank=2, connectivity=3) + >>> bright_on_gray = np.array([[2, 3, 3, 3, 2], + ... [3, 4, 5, 4, 3], + ... [3, 5, 9, 5, 3], + ... [3, 4, 5, 4, 3], + ... [2, 3, 3, 3, 2]]) + >>> white_tophat(input=bright_on_gray, structure=square) + array([[0, 0, 0, 0, 0], + [0, 0, 1, 0, 0], + [0, 1, 5, 1, 0], + [0, 0, 1, 0, 0], + [0, 0, 0, 0, 0]]) + + """ + input = np.asarray(input) + + if (size is not None) and (footprint is not None): + warnings.warn("ignoring size because footprint is set", + UserWarning, stacklevel=2) + tmp = grey_erosion(input, size, footprint, structure, None, mode, + cval, origin, axes=axes) + tmp = grey_dilation(tmp, size, footprint, structure, output, mode, + cval, origin, axes=axes) + if tmp is None: + tmp = output + + if input.dtype == np.bool_ and tmp.dtype == np.bool_: + np.bitwise_xor(input, tmp, out=tmp) + else: + np.subtract(input, tmp, out=tmp) + return tmp + + +def black_tophat(input, size=None, footprint=None, structure=None, output=None, + mode="reflect", cval=0.0, origin=0, *, axes=None): + """ + Multidimensional black tophat filter. + + Parameters + ---------- + input : array_like + Input. + size : tuple of ints, optional + Shape of a flat and full structuring element used for the filter. + Optional if `footprint` or `structure` is provided. + footprint : array of ints, optional + Positions of non-infinite elements of a flat structuring element + used for the black tophat filter. + structure : array of ints, optional + Structuring element used for the filter. `structure` may be a non-flat + structuring element. The `structure` array applies offsets to the + pixels in a neighborhood (the offset is additive during dilation and + subtractive during erosion) + output : array, optional + An array used for storing the output of the filter may be provided. + mode : {'reflect', 'constant', 'nearest', 'mirror', 'wrap'}, optional + The `mode` parameter determines how the array borders are + handled, where `cval` is the value when mode is equal to + 'constant'. Default is 'reflect' + cval : scalar, optional + Value to fill past edges of input if `mode` is 'constant'. Default + is 0.0. + origin : scalar, optional + The `origin` parameter controls the placement of the filter. + Default 0 + axes : tuple of int or None + The axes over which to apply the filter. If None, `input` is filtered + along all axes. If an `origin` tuple is provided, its length must match + the number of axes. + + Returns + ------- + black_tophat : ndarray + Result of the filter of `input` with `structure`. + + See Also + -------- + white_tophat, grey_opening, grey_closing + + Examples + -------- + Change dark peak to bright peak and subtract background. + + >>> from scipy.ndimage import generate_binary_structure, black_tophat + >>> import numpy as np + >>> square = generate_binary_structure(rank=2, connectivity=3) + >>> dark_on_gray = np.array([[7, 6, 6, 6, 7], + ... [6, 5, 4, 5, 6], + ... [6, 4, 0, 4, 6], + ... [6, 5, 4, 5, 6], + ... [7, 6, 6, 6, 7]]) + >>> black_tophat(input=dark_on_gray, structure=square) + array([[0, 0, 0, 0, 0], + [0, 0, 1, 0, 0], + [0, 1, 5, 1, 0], + [0, 0, 1, 0, 0], + [0, 0, 0, 0, 0]]) + + """ + input = np.asarray(input) + + if (size is not None) and (footprint is not None): + warnings.warn("ignoring size because footprint is set", + UserWarning, stacklevel=2) + tmp = grey_dilation(input, size, footprint, structure, None, mode, + cval, origin, axes=axes) + tmp = grey_erosion(tmp, size, footprint, structure, output, mode, + cval, origin, axes=axes) + if tmp is None: + tmp = output + + if input.dtype == np.bool_ and tmp.dtype == np.bool_: + np.bitwise_xor(tmp, input, out=tmp) + else: + np.subtract(tmp, input, out=tmp) + return tmp + + +def distance_transform_bf(input, metric="euclidean", sampling=None, + return_distances=True, return_indices=False, + distances=None, indices=None): + """ + Distance transform function by a brute force algorithm. + + This function calculates the distance transform of the `input`, by + replacing each foreground (non-zero) element, with its + shortest distance to the background (any zero-valued element). + + In addition to the distance transform, the feature transform can + be calculated. In this case the index of the closest background + element to each foreground element is returned in a separate array. + + Parameters + ---------- + input : array_like + Input + metric : {'euclidean', 'taxicab', 'chessboard'}, optional + 'cityblock' and 'manhattan' are also valid, and map to 'taxicab'. + The default is 'euclidean'. + sampling : float, or sequence of float, optional + This parameter is only used when `metric` is 'euclidean'. + Spacing of elements along each dimension. If a sequence, must be of + length equal to the input rank; if a single number, this is used for + all axes. If not specified, a grid spacing of unity is implied. + return_distances : bool, optional + Whether to calculate the distance transform. + Default is True. + return_indices : bool, optional + Whether to calculate the feature transform. + Default is False. + distances : ndarray, optional + An output array to store the calculated distance transform, instead of + returning it. + `return_distances` must be True. + It must be the same shape as `input`, and of type float64 if `metric` + is 'euclidean', uint32 otherwise. + indices : int32 ndarray, optional + An output array to store the calculated feature transform, instead of + returning it. + `return_indicies` must be True. + Its shape must be ``(input.ndim,) + input.shape``. + + Returns + ------- + distances : ndarray, optional + The calculated distance transform. Returned only when + `return_distances` is True and `distances` is not supplied. + It will have the same shape as the input array. + indices : int32 ndarray, optional + The calculated feature transform. It has an input-shaped array for each + dimension of the input. See distance_transform_edt documentation for an + example. + Returned only when `return_indices` is True and `indices` is not + supplied. + + See Also + -------- + distance_transform_cdt : Faster distance transform for taxicab and + chessboard metrics + distance_transform_edt : Faster distance transform for euclidean metric + + Notes + ----- + This function employs a slow brute force algorithm. See also the + function `distance_transform_cdt` for more efficient taxicab [1]_ and + chessboard algorithms [2]_. + + References + ---------- + .. [1] Taxicab distance. Wikipedia, 2023. + https://en.wikipedia.org/wiki/Taxicab_geometry + .. [2] Chessboard distance. Wikipedia, 2023. + https://en.wikipedia.org/wiki/Chebyshev_distance + + Examples + -------- + Import the necessary modules. + + >>> import numpy as np + >>> from scipy.ndimage import distance_transform_bf + >>> import matplotlib.pyplot as plt + >>> from mpl_toolkits.axes_grid1 import ImageGrid + + First, we create a toy binary image. + + >>> def add_circle(center_x, center_y, radius, image, fillvalue=1): + ... # fill circular area with 1 + ... xx, yy = np.mgrid[:image.shape[0], :image.shape[1]] + ... circle = (xx - center_x) ** 2 + (yy - center_y) ** 2 + ... circle_shape = np.sqrt(circle) < radius + ... image[circle_shape] = fillvalue + ... return image + >>> image = np.zeros((100, 100), dtype=np.uint8) + >>> image[35:65, 20:80] = 1 + >>> image = add_circle(28, 65, 10, image) + >>> image = add_circle(37, 30, 10, image) + >>> image = add_circle(70, 45, 20, image) + >>> image = add_circle(45, 80, 10, image) + + Next, we set up the figure. + + >>> fig = plt.figure(figsize=(8, 8)) # set up the figure structure + >>> grid = ImageGrid(fig, 111, nrows_ncols=(2, 2), axes_pad=(0.4, 0.3), + ... label_mode="1", share_all=True, + ... cbar_location="right", cbar_mode="each", + ... cbar_size="7%", cbar_pad="2%") + >>> for ax in grid: + ... ax.axis('off') # remove axes from images + + The top left image is the original binary image. + + >>> binary_image = grid[0].imshow(image, cmap='gray') + >>> cbar_binary_image = grid.cbar_axes[0].colorbar(binary_image) + >>> cbar_binary_image.set_ticks([0, 1]) + >>> grid[0].set_title("Binary image: foreground in white") + + The distance transform calculates the distance between foreground pixels + and the image background according to a distance metric. Available metrics + in `distance_transform_bf` are: ``euclidean`` (default), ``taxicab`` + and ``chessboard``. The top right image contains the distance transform + based on the ``euclidean`` metric. + + >>> distance_transform_euclidean = distance_transform_bf(image) + >>> euclidean_transform = grid[1].imshow(distance_transform_euclidean, + ... cmap='gray') + >>> cbar_euclidean = grid.cbar_axes[1].colorbar(euclidean_transform) + >>> colorbar_ticks = [0, 10, 20] + >>> cbar_euclidean.set_ticks(colorbar_ticks) + >>> grid[1].set_title("Euclidean distance") + + The lower left image contains the distance transform using the ``taxicab`` + metric. + + >>> distance_transform_taxicab = distance_transform_bf(image, + ... metric='taxicab') + >>> taxicab_transformation = grid[2].imshow(distance_transform_taxicab, + ... cmap='gray') + >>> cbar_taxicab = grid.cbar_axes[2].colorbar(taxicab_transformation) + >>> cbar_taxicab.set_ticks(colorbar_ticks) + >>> grid[2].set_title("Taxicab distance") + + Finally, the lower right image contains the distance transform using the + ``chessboard`` metric. + + >>> distance_transform_cb = distance_transform_bf(image, + ... metric='chessboard') + >>> chessboard_transformation = grid[3].imshow(distance_transform_cb, + ... cmap='gray') + >>> cbar_taxicab = grid.cbar_axes[3].colorbar(chessboard_transformation) + >>> cbar_taxicab.set_ticks(colorbar_ticks) + >>> grid[3].set_title("Chessboard distance") + >>> plt.show() + + """ + ft_inplace = isinstance(indices, np.ndarray) + dt_inplace = isinstance(distances, np.ndarray) + _distance_tranform_arg_check( + dt_inplace, ft_inplace, return_distances, return_indices + ) + + tmp1 = np.asarray(input) != 0 + struct = generate_binary_structure(tmp1.ndim, tmp1.ndim) + tmp2 = binary_dilation(tmp1, struct) + tmp2 = np.logical_xor(tmp1, tmp2) + tmp1 = tmp1.astype(np.int8) - tmp2.astype(np.int8) + metric = metric.lower() + if metric == 'euclidean': + metric = 1 + elif metric in ['taxicab', 'cityblock', 'manhattan']: + metric = 2 + elif metric == 'chessboard': + metric = 3 + else: + raise RuntimeError('distance metric not supported') + if sampling is not None: + sampling = _ni_support._normalize_sequence(sampling, tmp1.ndim) + sampling = np.asarray(sampling, dtype=np.float64) + if not sampling.flags.contiguous: + sampling = sampling.copy() + if return_indices: + ft = np.zeros(tmp1.shape, dtype=np.int32) + else: + ft = None + if return_distances: + if distances is None: + if metric == 1: + dt = np.zeros(tmp1.shape, dtype=np.float64) + else: + dt = np.zeros(tmp1.shape, dtype=np.uint32) + else: + if distances.shape != tmp1.shape: + raise RuntimeError('distances array has wrong shape') + if metric == 1: + if distances.dtype.type != np.float64: + raise RuntimeError('distances array must be float64') + else: + if distances.dtype.type != np.uint32: + raise RuntimeError('distances array must be uint32') + dt = distances + else: + dt = None + + _nd_image.distance_transform_bf(tmp1, metric, sampling, dt, ft) + if return_indices: + if isinstance(indices, np.ndarray): + if indices.dtype.type != np.int32: + raise RuntimeError('indices array must be int32') + if indices.shape != (tmp1.ndim,) + tmp1.shape: + raise RuntimeError('indices array has wrong shape') + tmp2 = indices + else: + tmp2 = np.indices(tmp1.shape, dtype=np.int32) + ft = np.ravel(ft) + for ii in range(tmp2.shape[0]): + rtmp = np.ravel(tmp2[ii, ...])[ft] + rtmp.shape = tmp1.shape + tmp2[ii, ...] = rtmp + ft = tmp2 + + # construct and return the result + result = [] + if return_distances and not dt_inplace: + result.append(dt) + if return_indices and not ft_inplace: + result.append(ft) + + if len(result) == 2: + return tuple(result) + elif len(result) == 1: + return result[0] + else: + return None + + +def distance_transform_cdt(input, metric='chessboard', return_distances=True, + return_indices=False, distances=None, indices=None): + """ + Distance transform for chamfer type of transforms. + + This function calculates the distance transform of the `input`, by + replacing each foreground (non-zero) element, with its + shortest distance to the background (any zero-valued element). + + In addition to the distance transform, the feature transform can + be calculated. In this case the index of the closest background + element to each foreground element is returned in a separate array. + + Parameters + ---------- + input : array_like + Input. Values of 0 are treated as background. + metric : {'chessboard', 'taxicab'} or array_like, optional + The `metric` determines the type of chamfering that is done. If the + `metric` is equal to 'taxicab' a structure is generated using + `generate_binary_structure` with a squared distance equal to 1. If + the `metric` is equal to 'chessboard', a `metric` is generated + using `generate_binary_structure` with a squared distance equal to + the dimensionality of the array. These choices correspond to the + common interpretations of the 'taxicab' and the 'chessboard' + distance metrics in two dimensions. + A custom metric may be provided, in the form of a matrix where + each dimension has a length of three. + 'cityblock' and 'manhattan' are also valid, and map to 'taxicab'. + The default is 'chessboard'. + return_distances : bool, optional + Whether to calculate the distance transform. + Default is True. + return_indices : bool, optional + Whether to calculate the feature transform. + Default is False. + distances : int32 ndarray, optional + An output array to store the calculated distance transform, instead of + returning it. + `return_distances` must be True. + It must be the same shape as `input`. + indices : int32 ndarray, optional + An output array to store the calculated feature transform, instead of + returning it. + `return_indicies` must be True. + Its shape must be ``(input.ndim,) + input.shape``. + + Returns + ------- + distances : int32 ndarray, optional + The calculated distance transform. Returned only when + `return_distances` is True, and `distances` is not supplied. + It will have the same shape as the input array. + indices : int32 ndarray, optional + The calculated feature transform. It has an input-shaped array for each + dimension of the input. See distance_transform_edt documentation for an + example. + Returned only when `return_indices` is True, and `indices` is not + supplied. + + See Also + -------- + distance_transform_edt : Fast distance transform for euclidean metric + distance_transform_bf : Distance transform for different metrics using + a slower brute force algorithm + + Examples + -------- + Import the necessary modules. + + >>> import numpy as np + >>> from scipy.ndimage import distance_transform_cdt + >>> import matplotlib.pyplot as plt + >>> from mpl_toolkits.axes_grid1 import ImageGrid + + First, we create a toy binary image. + + >>> def add_circle(center_x, center_y, radius, image, fillvalue=1): + ... # fill circular area with 1 + ... xx, yy = np.mgrid[:image.shape[0], :image.shape[1]] + ... circle = (xx - center_x) ** 2 + (yy - center_y) ** 2 + ... circle_shape = np.sqrt(circle) < radius + ... image[circle_shape] = fillvalue + ... return image + >>> image = np.zeros((100, 100), dtype=np.uint8) + >>> image[35:65, 20:80] = 1 + >>> image = add_circle(28, 65, 10, image) + >>> image = add_circle(37, 30, 10, image) + >>> image = add_circle(70, 45, 20, image) + >>> image = add_circle(45, 80, 10, image) + + Next, we set up the figure. + + >>> fig = plt.figure(figsize=(5, 15)) + >>> grid = ImageGrid(fig, 111, nrows_ncols=(3, 1), axes_pad=(0.5, 0.3), + ... label_mode="1", share_all=True, + ... cbar_location="right", cbar_mode="each", + ... cbar_size="7%", cbar_pad="2%") + >>> for ax in grid: + ... ax.axis('off') + >>> top, middle, bottom = grid + >>> colorbar_ticks = [0, 10, 20] + + The top image contains the original binary image. + + >>> binary_image = top.imshow(image, cmap='gray') + >>> cbar_binary_image = top.cax.colorbar(binary_image) + >>> cbar_binary_image.set_ticks([0, 1]) + >>> top.set_title("Binary image: foreground in white") + + The middle image contains the distance transform using the ``taxicab`` + metric. + + >>> distance_taxicab = distance_transform_cdt(image, metric="taxicab") + >>> taxicab_transform = middle.imshow(distance_taxicab, cmap='gray') + >>> cbar_taxicab = middle.cax.colorbar(taxicab_transform) + >>> cbar_taxicab.set_ticks(colorbar_ticks) + >>> middle.set_title("Taxicab metric") + + The bottom image contains the distance transform using the ``chessboard`` + metric. + + >>> distance_chessboard = distance_transform_cdt(image, + ... metric="chessboard") + >>> chessboard_transform = bottom.imshow(distance_chessboard, cmap='gray') + >>> cbar_chessboard = bottom.cax.colorbar(chessboard_transform) + >>> cbar_chessboard.set_ticks(colorbar_ticks) + >>> bottom.set_title("Chessboard metric") + >>> plt.tight_layout() + >>> plt.show() + + """ + ft_inplace = isinstance(indices, np.ndarray) + dt_inplace = isinstance(distances, np.ndarray) + _distance_tranform_arg_check( + dt_inplace, ft_inplace, return_distances, return_indices + ) + input = np.asarray(input) + if isinstance(metric, str): + if metric in ['taxicab', 'cityblock', 'manhattan']: + rank = input.ndim + metric = generate_binary_structure(rank, 1) + elif metric == 'chessboard': + rank = input.ndim + metric = generate_binary_structure(rank, rank) + else: + raise ValueError('invalid metric provided') + else: + try: + metric = np.asarray(metric) + except Exception as e: + raise ValueError('invalid metric provided') from e + for s in metric.shape: + if s != 3: + raise ValueError('metric sizes must be equal to 3') + + if not metric.flags.contiguous: + metric = metric.copy() + if dt_inplace: + if distances.dtype.type != np.int32: + raise ValueError('distances must be of int32 type') + if distances.shape != input.shape: + raise ValueError('distances has wrong shape') + dt = distances + dt[...] = np.where(input, -1, 0).astype(np.int32) + else: + dt = np.where(input, -1, 0).astype(np.int32) + + rank = dt.ndim + if return_indices: + ft = np.arange(dt.size, dtype=np.int32) + ft.shape = dt.shape + else: + ft = None + + _nd_image.distance_transform_op(metric, dt, ft) + dt = dt[tuple([slice(None, None, -1)] * rank)] + if return_indices: + ft = ft[tuple([slice(None, None, -1)] * rank)] + _nd_image.distance_transform_op(metric, dt, ft) + dt = dt[tuple([slice(None, None, -1)] * rank)] + if return_indices: + ft = ft[tuple([slice(None, None, -1)] * rank)] + ft = np.ravel(ft) + if ft_inplace: + if indices.dtype.type != np.int32: + raise ValueError('indices array must be int32') + if indices.shape != (dt.ndim,) + dt.shape: + raise ValueError('indices array has wrong shape') + tmp = indices + else: + tmp = np.indices(dt.shape, dtype=np.int32) + for ii in range(tmp.shape[0]): + rtmp = np.ravel(tmp[ii, ...])[ft] + rtmp.shape = dt.shape + tmp[ii, ...] = rtmp + ft = tmp + + # construct and return the result + result = [] + if return_distances and not dt_inplace: + result.append(dt) + if return_indices and not ft_inplace: + result.append(ft) + + if len(result) == 2: + return tuple(result) + elif len(result) == 1: + return result[0] + else: + return None + + +def distance_transform_edt(input, sampling=None, return_distances=True, + return_indices=False, distances=None, indices=None): + """ + Exact Euclidean distance transform. + + This function calculates the distance transform of the `input`, by + replacing each foreground (non-zero) element, with its + shortest distance to the background (any zero-valued element). + + In addition to the distance transform, the feature transform can + be calculated. In this case the index of the closest background + element to each foreground element is returned in a separate array. + + Parameters + ---------- + input : array_like + Input data to transform. Can be any type but will be converted + into binary: 1 wherever input equates to True, 0 elsewhere. + sampling : float, or sequence of float, optional + Spacing of elements along each dimension. If a sequence, must be of + length equal to the input rank; if a single number, this is used for + all axes. If not specified, a grid spacing of unity is implied. + return_distances : bool, optional + Whether to calculate the distance transform. + Default is True. + return_indices : bool, optional + Whether to calculate the feature transform. + Default is False. + distances : float64 ndarray, optional + An output array to store the calculated distance transform, instead of + returning it. + `return_distances` must be True. + It must be the same shape as `input`. + indices : int32 ndarray, optional + An output array to store the calculated feature transform, instead of + returning it. + `return_indicies` must be True. + Its shape must be ``(input.ndim,) + input.shape``. + + Returns + ------- + distances : float64 ndarray, optional + The calculated distance transform. Returned only when + `return_distances` is True and `distances` is not supplied. + It will have the same shape as the input array. + indices : int32 ndarray, optional + The calculated feature transform. It has an input-shaped array for each + dimension of the input. See example below. + Returned only when `return_indices` is True and `indices` is not + supplied. + + Notes + ----- + The Euclidean distance transform gives values of the Euclidean + distance:: + + n + y_i = sqrt(sum (x[i]-b[i])**2) + i + + where b[i] is the background point (value 0) with the smallest + Euclidean distance to input points x[i], and n is the + number of dimensions. + + Examples + -------- + >>> from scipy import ndimage + >>> import numpy as np + >>> a = np.array(([0,1,1,1,1], + ... [0,0,1,1,1], + ... [0,1,1,1,1], + ... [0,1,1,1,0], + ... [0,1,1,0,0])) + >>> ndimage.distance_transform_edt(a) + array([[ 0. , 1. , 1.4142, 2.2361, 3. ], + [ 0. , 0. , 1. , 2. , 2. ], + [ 0. , 1. , 1.4142, 1.4142, 1. ], + [ 0. , 1. , 1.4142, 1. , 0. ], + [ 0. , 1. , 1. , 0. , 0. ]]) + + With a sampling of 2 units along x, 1 along y: + + >>> ndimage.distance_transform_edt(a, sampling=[2,1]) + array([[ 0. , 1. , 2. , 2.8284, 3.6056], + [ 0. , 0. , 1. , 2. , 3. ], + [ 0. , 1. , 2. , 2.2361, 2. ], + [ 0. , 1. , 2. , 1. , 0. ], + [ 0. , 1. , 1. , 0. , 0. ]]) + + Asking for indices as well: + + >>> edt, inds = ndimage.distance_transform_edt(a, return_indices=True) + >>> inds + array([[[0, 0, 1, 1, 3], + [1, 1, 1, 1, 3], + [2, 2, 1, 3, 3], + [3, 3, 4, 4, 3], + [4, 4, 4, 4, 4]], + [[0, 0, 1, 1, 4], + [0, 1, 1, 1, 4], + [0, 0, 1, 4, 4], + [0, 0, 3, 3, 4], + [0, 0, 3, 3, 4]]], dtype=int32) + + With arrays provided for inplace outputs: + + >>> indices = np.zeros(((np.ndim(a),) + a.shape), dtype=np.int32) + >>> ndimage.distance_transform_edt(a, return_indices=True, indices=indices) + array([[ 0. , 1. , 1.4142, 2.2361, 3. ], + [ 0. , 0. , 1. , 2. , 2. ], + [ 0. , 1. , 1.4142, 1.4142, 1. ], + [ 0. , 1. , 1.4142, 1. , 0. ], + [ 0. , 1. , 1. , 0. , 0. ]]) + >>> indices + array([[[0, 0, 1, 1, 3], + [1, 1, 1, 1, 3], + [2, 2, 1, 3, 3], + [3, 3, 4, 4, 3], + [4, 4, 4, 4, 4]], + [[0, 0, 1, 1, 4], + [0, 1, 1, 1, 4], + [0, 0, 1, 4, 4], + [0, 0, 3, 3, 4], + [0, 0, 3, 3, 4]]], dtype=int32) + + """ + ft_inplace = isinstance(indices, np.ndarray) + dt_inplace = isinstance(distances, np.ndarray) + _distance_tranform_arg_check( + dt_inplace, ft_inplace, return_distances, return_indices + ) + + # calculate the feature transform + input = np.atleast_1d(np.where(input, 1, 0).astype(np.int8)) + if sampling is not None: + sampling = _ni_support._normalize_sequence(sampling, input.ndim) + sampling = np.asarray(sampling, dtype=np.float64) + if not sampling.flags.contiguous: + sampling = sampling.copy() + + if ft_inplace: + ft = indices + if ft.shape != (input.ndim,) + input.shape: + raise RuntimeError('indices array has wrong shape') + if ft.dtype.type != np.int32: + raise RuntimeError('indices array must be int32') + else: + ft = np.zeros((input.ndim,) + input.shape, dtype=np.int32) + + _nd_image.euclidean_feature_transform(input, sampling, ft) + # if requested, calculate the distance transform + if return_distances: + dt = ft - np.indices(input.shape, dtype=ft.dtype) + dt = dt.astype(np.float64) + if sampling is not None: + for ii in range(len(sampling)): + dt[ii, ...] *= sampling[ii] + np.multiply(dt, dt, dt) + if dt_inplace: + dt = np.add.reduce(dt, axis=0) + if distances.shape != dt.shape: + raise RuntimeError('distances array has wrong shape') + if distances.dtype.type != np.float64: + raise RuntimeError('distances array must be float64') + np.sqrt(dt, distances) + else: + dt = np.add.reduce(dt, axis=0) + dt = np.sqrt(dt) + + # construct and return the result + result = [] + if return_distances and not dt_inplace: + result.append(dt) + if return_indices and not ft_inplace: + result.append(ft) + + if len(result) == 2: + return tuple(result) + elif len(result) == 1: + return result[0] + else: + return None + + +def _distance_tranform_arg_check(distances_out, indices_out, + return_distances, return_indices): + """Raise a RuntimeError if the arguments are invalid""" + error_msgs = [] + if (not return_distances) and (not return_indices): + error_msgs.append( + 'at least one of return_distances/return_indices must be True') + if distances_out and not return_distances: + error_msgs.append( + 'return_distances must be True if distances is supplied' + ) + if indices_out and not return_indices: + error_msgs.append('return_indices must be True if indices is supplied') + if error_msgs: + raise RuntimeError(', '.join(error_msgs))