2026-02-10 11:17:31 +08:00
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import cv2
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2026-02-27 15:26:07 +08:00
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import numpy as np
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2026-02-10 11:17:31 +08:00
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def my_imnormalize(img, mean, std, to_rgb=True):
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"""Inplace normalize an image with mean and std.
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Args:
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img (ndarray): Image to be normalized.
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mean (ndarray): The mean to be used for normalize.
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std (ndarray): The std to be used for normalize.
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to_rgb (bool): Whether to convert to rgb.
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Returns:
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ndarray: The normalized image.
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"""
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# cv2 inplace normalization does not accept uint8
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img = img.copy().astype(np.float32)
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assert img.dtype != np.uint8
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mean = np.float64(mean.reshape(1, -1))
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stdinv = 1 / np.float64(std.reshape(1, -1))
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if to_rgb:
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cv2.cvtColor(img, cv2.COLOR_BGR2RGB, img) # inplace
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cv2.subtract(img, mean, img) # inplace
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cv2.multiply(img, stdinv, img) # inplace
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return img
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