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| import cv2 | |
| import numpy as np | |
| ## aug functions | |
| def identity_func(img): | |
| return img | |
| def autocontrast_func(img, cutoff=0): | |
| ''' | |
| same output as PIL.ImageOps.autocontrast | |
| ''' | |
| n_bins = 256 | |
| def tune_channel(ch): | |
| n = ch.size | |
| cut = cutoff * n // 100 | |
| if cut == 0: | |
| high, low = ch.max(), ch.min() | |
| else: | |
| hist = cv2.calcHist([ch], [0], None, [n_bins], [0, n_bins]) | |
| low = np.argwhere(np.cumsum(hist) > cut) | |
| low = 0 if low.shape[0] == 0 else low[0] | |
| high = np.argwhere(np.cumsum(hist[::-1]) > cut) | |
| high = n_bins - 1 if high.shape[0] == 0 else n_bins - 1 - high[0] | |
| if high <= low: | |
| table = np.arange(n_bins) | |
| else: | |
| scale = (n_bins - 1) / (high - low) | |
| offset = -low * scale | |
| table = np.arange(n_bins) * scale + offset | |
| table[table < 0] = 0 | |
| table[table > n_bins - 1] = n_bins - 1 | |
| table = table.clip(0, 255).astype(np.uint8) | |
| return table[ch] | |
| channels = [tune_channel(ch) for ch in cv2.split(img)] | |
| out = cv2.merge(channels) | |
| return out | |
| def equalize_func(img): | |
| ''' | |
| same output as PIL.ImageOps.equalize | |
| PIL's implementation is different from cv2.equalize | |
| ''' | |
| n_bins = 256 | |
| def tune_channel(ch): | |
| hist = cv2.calcHist([ch], [0], None, [n_bins], [0, n_bins]) | |
| non_zero_hist = hist[hist != 0].reshape(-1) | |
| step = np.sum(non_zero_hist[:-1]) // (n_bins - 1) | |
| if step == 0: return ch | |
| n = np.empty_like(hist) | |
| n[0] = step // 2 | |
| n[1:] = hist[:-1] | |
| table = (np.cumsum(n) // step).clip(0, 255).astype(np.uint8) | |
| return table[ch] | |
| channels = [tune_channel(ch) for ch in cv2.split(img)] | |
| out = cv2.merge(channels) | |
| return out | |
| def rotate_func(img, degree, fill=(0, 0, 0)): | |
| ''' | |
| like PIL, rotate by degree, not radians | |
| ''' | |
| H, W = img.shape[0], img.shape[1] | |
| center = W / 2, H / 2 | |
| M = cv2.getRotationMatrix2D(center, degree, 1) | |
| out = cv2.warpAffine(img, M, (W, H), borderValue=fill) | |
| return out | |
| def solarize_func(img, thresh=128): | |
| ''' | |
| same output as PIL.ImageOps.posterize | |
| ''' | |
| table = np.array([el if el < thresh else 255 - el for el in range(256)]) | |
| table = table.clip(0, 255).astype(np.uint8) | |
| out = table[img] | |
| return out | |
| def color_func(img, factor): | |
| ''' | |
| same output as PIL.ImageEnhance.Color | |
| ''' | |
| ## implementation according to PIL definition, quite slow | |
| # degenerate = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)[:, :, np.newaxis] | |
| # out = blend(degenerate, img, factor) | |
| # M = ( | |
| # np.eye(3) * factor | |
| # + np.float32([0.114, 0.587, 0.299]).reshape(3, 1) * (1. - factor) | |
| # )[np.newaxis, np.newaxis, :] | |
| M = ( | |
| np.float32([ | |
| [0.886, -0.114, -0.114], | |
| [-0.587, 0.413, -0.587], | |
| [-0.299, -0.299, 0.701]]) * factor | |
| + np.float32([[0.114], [0.587], [0.299]]) | |
| ) | |
| out = np.matmul(img, M).clip(0, 255).astype(np.uint8) | |
| return out | |
| def contrast_func(img, factor): | |
| """ | |
| same output as PIL.ImageEnhance.Contrast | |
| """ | |
| mean = np.sum(np.mean(img, axis=(0, 1)) * np.array([0.114, 0.587, 0.299])) | |
| table = np.array([( | |
| el - mean) * factor + mean | |
| for el in range(256) | |
| ]).clip(0, 255).astype(np.uint8) | |
| out = table[img] | |
| return out | |
| def brightness_func(img, factor): | |
| ''' | |
| same output as PIL.ImageEnhance.Contrast | |
| ''' | |
| table = (np.arange(256, dtype=np.float32) * factor).clip(0, 255).astype(np.uint8) | |
| out = table[img] | |
| return out | |
| def sharpness_func(img, factor): | |
| ''' | |
| The differences the this result and PIL are all on the 4 boundaries, the center | |
| areas are same | |
| ''' | |
| kernel = np.ones((3, 3), dtype=np.float32) | |
| kernel[1][1] = 5 | |
| kernel /= 13 | |
| degenerate = cv2.filter2D(img, -1, kernel) | |
| if factor == 0.0: | |
| out = degenerate | |
| elif factor == 1.0: | |
| out = img | |
| else: | |
| out = img.astype(np.float32) | |
| degenerate = degenerate.astype(np.float32)[1:-1, 1:-1, :] | |
| out[1:-1, 1:-1, :] = degenerate + factor * (out[1:-1, 1:-1, :] - degenerate) | |
| out = out.astype(np.uint8) | |
| return out | |
| def shear_x_func(img, factor, fill=(0, 0, 0)): | |
| H, W = img.shape[0], img.shape[1] | |
| M = np.float32([[1, factor, 0], [0, 1, 0]]) | |
| out = cv2.warpAffine(img, M, (W, H), borderValue=fill, flags=cv2.INTER_LINEAR).astype(np.uint8) | |
| return out | |
| def translate_x_func(img, offset, fill=(0, 0, 0)): | |
| ''' | |
| same output as PIL.Image.transform | |
| ''' | |
| H, W = img.shape[0], img.shape[1] | |
| M = np.float32([[1, 0, -offset], [0, 1, 0]]) | |
| out = cv2.warpAffine(img, M, (W, H), borderValue=fill, flags=cv2.INTER_LINEAR).astype(np.uint8) | |
| return out | |
| def translate_y_func(img, offset, fill=(0, 0, 0)): | |
| ''' | |
| same output as PIL.Image.transform | |
| ''' | |
| H, W = img.shape[0], img.shape[1] | |
| M = np.float32([[1, 0, 0], [0, 1, -offset]]) | |
| out = cv2.warpAffine(img, M, (W, H), borderValue=fill, flags=cv2.INTER_LINEAR).astype(np.uint8) | |
| return out | |
| def posterize_func(img, bits): | |
| ''' | |
| same output as PIL.ImageOps.posterize | |
| ''' | |
| out = np.bitwise_and(img, np.uint8(255 << (8 - bits))) | |
| return out | |
| def shear_y_func(img, factor, fill=(0, 0, 0)): | |
| H, W = img.shape[0], img.shape[1] | |
| M = np.float32([[1, 0, 0], [factor, 1, 0]]) | |
| out = cv2.warpAffine(img, M, (W, H), borderValue=fill, flags=cv2.INTER_LINEAR).astype(np.uint8) | |
| return out | |
| def cutout_func(img, pad_size, replace=(0, 0, 0)): | |
| replace = np.array(replace, dtype=np.uint8) | |
| H, W = img.shape[0], img.shape[1] | |
| rh, rw = np.random.random(2) | |
| pad_size = pad_size // 2 | |
| ch, cw = int(rh * H), int(rw * W) | |
| x1, x2 = max(ch - pad_size, 0), min(ch + pad_size, H) | |
| y1, y2 = max(cw - pad_size, 0), min(cw + pad_size, W) | |
| out = img.copy() | |
| out[x1:x2, y1:y2, :] = replace | |
| return out | |
| ### level to args | |
| def enhance_level_to_args(MAX_LEVEL): | |
| def level_to_args(level): | |
| return ((level / MAX_LEVEL) * 1.8 + 0.1,) | |
| return level_to_args | |
| def shear_level_to_args(MAX_LEVEL, replace_value): | |
| def level_to_args(level): | |
| level = (level / MAX_LEVEL) * 0.3 | |
| if np.random.random() > 0.5: level = -level | |
| return (level, replace_value) | |
| return level_to_args | |
| def translate_level_to_args(translate_const, MAX_LEVEL, replace_value): | |
| def level_to_args(level): | |
| level = (level / MAX_LEVEL) * float(translate_const) | |
| if np.random.random() > 0.5: level = -level | |
| return (level, replace_value) | |
| return level_to_args | |
| def cutout_level_to_args(cutout_const, MAX_LEVEL, replace_value): | |
| def level_to_args(level): | |
| level = int((level / MAX_LEVEL) * cutout_const) | |
| return (level, replace_value) | |
| return level_to_args | |
| def solarize_level_to_args(MAX_LEVEL): | |
| def level_to_args(level): | |
| level = int((level / MAX_LEVEL) * 256) | |
| return (level, ) | |
| return level_to_args | |
| def none_level_to_args(level): | |
| return () | |
| def posterize_level_to_args(MAX_LEVEL): | |
| def level_to_args(level): | |
| level = int((level / MAX_LEVEL) * 4) | |
| return (level, ) | |
| return level_to_args | |
| def rotate_level_to_args(MAX_LEVEL, replace_value): | |
| def level_to_args(level): | |
| level = (level / MAX_LEVEL) * 30 | |
| if np.random.random() < 0.5: | |
| level = -level | |
| return (level, replace_value) | |
| return level_to_args | |
| func_dict = { | |
| 'Identity': identity_func, | |
| 'AutoContrast': autocontrast_func, | |
| 'Equalize': equalize_func, | |
| 'Rotate': rotate_func, | |
| 'Solarize': solarize_func, | |
| 'Color': color_func, | |
| 'Contrast': contrast_func, | |
| 'Brightness': brightness_func, | |
| 'Sharpness': sharpness_func, | |
| 'ShearX': shear_x_func, | |
| 'TranslateX': translate_x_func, | |
| 'TranslateY': translate_y_func, | |
| 'Posterize': posterize_func, | |
| 'ShearY': shear_y_func, | |
| } | |
| translate_const = 10 | |
| MAX_LEVEL = 10 | |
| replace_value = (128, 128, 128) | |
| arg_dict = { | |
| 'Identity': none_level_to_args, | |
| 'AutoContrast': none_level_to_args, | |
| 'Equalize': none_level_to_args, | |
| 'Rotate': rotate_level_to_args(MAX_LEVEL, replace_value), | |
| 'Solarize': solarize_level_to_args(MAX_LEVEL), | |
| 'Color': enhance_level_to_args(MAX_LEVEL), | |
| 'Contrast': enhance_level_to_args(MAX_LEVEL), | |
| 'Brightness': enhance_level_to_args(MAX_LEVEL), | |
| 'Sharpness': enhance_level_to_args(MAX_LEVEL), | |
| 'ShearX': shear_level_to_args(MAX_LEVEL, replace_value), | |
| 'TranslateX': translate_level_to_args( | |
| translate_const, MAX_LEVEL, replace_value | |
| ), | |
| 'TranslateY': translate_level_to_args( | |
| translate_const, MAX_LEVEL, replace_value | |
| ), | |
| 'Posterize': posterize_level_to_args(MAX_LEVEL), | |
| 'ShearY': shear_level_to_args(MAX_LEVEL, replace_value), | |
| } | |
| class RandomAugment(object): | |
| def __init__(self, N=2, M=10, isPIL=False, augs=[]): | |
| self.N = N | |
| self.M = M | |
| self.isPIL = isPIL | |
| if augs: | |
| self.augs = augs | |
| else: | |
| self.augs = list(arg_dict.keys()) | |
| def get_random_ops(self): | |
| sampled_ops = np.random.choice(self.augs, self.N) | |
| return [(op, 0.5, self.M) for op in sampled_ops] | |
| def __call__(self, img): | |
| if self.isPIL: | |
| img = np.array(img) | |
| ops = self.get_random_ops() | |
| for name, prob, level in ops: | |
| if np.random.random() > prob: | |
| continue | |
| args = arg_dict[name](level) | |
| img = func_dict[name](img, *args) | |
| return img | |
| if __name__ == '__main__': | |
| a = RandomAugment() | |
| img = np.random.randn(32, 32, 3) | |
| a(img) |