| import numpy as np | |
| def Process(img, num_colors=3, **param): | |
| """Converts a 2d image into to 3d image | |
| where each band corresponds to one colour. | |
| Note: Background is not considered a color. | |
| """ | |
| n, m = img.shape | |
| img_cpy = np.zeros((n, m, num_colors)) | |
| for color in range(0, num_colors): | |
| img_cpy[:, :, color] = (img == (color+1))*1 | |
| return img_cpy | |
| def Change_Colour(img, rule, *args): | |
| """ | |
| The rule is a mapping {0,1}^k -> {0,1,2,...k} | |
| Implemented as n x (k+1) array where $k$ is the number of colors. | |
| -> row 'i' corresponds to rule 'i'. | |
| -> Each rule will be of the form <0,1,0,1...,j> | |
| -> The last entry denotes the color to assign based on first 'k' | |
| entries. | |
| """ | |
| if rule is None: | |
| m, n, no_colors = img.shape | |
| out_img = np.zeros((m, n), dtype=np.int32) | |
| for col in range(no_colors): | |
| out_img[img[:, :, col] == 1] = col + 1 | |
| return out_img | |
| def func(arr, rule): | |
| ind = np.where(np.all(rule[:, :-1] == arr.reshape((1, -1)), axis=-1))[0] | |
| if len(ind) == 0: | |
| return 0 | |
| elif len(ind) > 1: | |
| raise Exception("More than two Color_Change rules match the input") | |
| else: | |
| return rule[ind[0], -1] | |
| img = np.apply_along_axis(func, 2, img, rule) | |
| return img | |