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8207382 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 | # copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
This code is refer from:
https://github.com/WenmuZhou/DBNet.pytorch/blob/master/data_loader/modules/make_shrink_map.py
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals
import numpy as np
import cv2
from shapely.geometry import Polygon
import pyclipper
__all__ = ["MakeShrinkMap"]
class MakeShrinkMap(object):
r"""
Making binary mask from detection data with ICDAR format.
Typically following the process of class `MakeICDARData`.
"""
def __init__(self, min_text_size=8, shrink_ratio=0.4, **kwargs):
self.min_text_size = min_text_size
self.shrink_ratio = shrink_ratio
if "total_epoch" in kwargs:
self._base_shrink_ratio = shrink_ratio
self._total_epoch = kwargs["total_epoch"]
def __call__(self, data):
image = data["image"]
text_polys = data["polys"]
ignore_tags = data["ignore_tags"]
h, w = image.shape[:2]
text_polys, ignore_tags = self.validate_polygons(text_polys, ignore_tags, h, w)
gt = np.zeros((h, w), dtype=np.float32)
mask = np.ones((h, w), dtype=np.float32)
for i in range(len(text_polys)):
polygon = text_polys[i]
height = max(polygon[:, 1]) - min(polygon[:, 1])
width = max(polygon[:, 0]) - min(polygon[:, 0])
if ignore_tags[i] or min(height, width) < self.min_text_size:
cv2.fillPoly(mask, polygon.astype(np.int32)[np.newaxis, :, :], 0)
ignore_tags[i] = True
else:
if np.isnan(polygon).any():
ignore_tags[i] = True
continue
polygon_shape = Polygon(polygon)
subject = [tuple(l) for l in polygon]
padding = pyclipper.PyclipperOffset()
padding.AddPath(subject, pyclipper.JT_ROUND, pyclipper.ET_CLOSEDPOLYGON)
shrunk = []
# Increase the shrink ratio every time we get multiple polygon returned back
shrink_ratio = self.shrink_ratio
if "epoch" in data and hasattr(self, "_base_shrink_ratio"):
shrink_ratio = self._base_shrink_ratio + 0.2 * data[
"epoch"
] / float(self._total_epoch)
possible_ratios = np.arange(shrink_ratio, 1, shrink_ratio)
np.append(possible_ratios, 1)
# print(possible_ratios)
for ratio in possible_ratios:
# print(f"Change shrink ratio to {ratio}")
distance = (
polygon_shape.area
* (1 - np.power(ratio, 2))
/ polygon_shape.length
)
shrunk = padding.Execute(-distance)
if len(shrunk) == 1:
break
if shrunk == []:
cv2.fillPoly(mask, polygon.astype(np.int32)[np.newaxis, :, :], 0)
ignore_tags[i] = True
continue
for each_shrink in shrunk:
shrink = np.array(each_shrink).reshape(-1, 2)
cv2.fillPoly(gt, [shrink.astype(np.int32)], 1)
data["shrink_map"] = gt
data["shrink_mask"] = mask
return data
def validate_polygons(self, polygons, ignore_tags, h, w):
"""
polygons (numpy.array, required): of shape (num_instances, num_points, 2)
"""
if len(polygons) == 0:
return polygons, ignore_tags
assert len(polygons) == len(ignore_tags)
for polygon in polygons:
polygon[:, 0] = np.clip(polygon[:, 0], 0, w - 1)
polygon[:, 1] = np.clip(polygon[:, 1], 0, h - 1)
for i in range(len(polygons)):
area = self.polygon_area(polygons[i])
if abs(area) < 1:
ignore_tags[i] = True
if area > 0:
polygons[i] = polygons[i][::-1, :]
return polygons, ignore_tags
def polygon_area(self, polygon):
"""
compute polygon area
"""
area = 0
q = polygon[-1]
for p in polygon:
area += p[0] * q[1] - p[1] * q[0]
q = p
return area / 2.0
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