python图片二值化

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导入相关库

import osimport cv2import numpy as np

stdfilt函数（详见：链接一、链接二）

def stdfilt(img, mask):    n = mask.sum()    n1 = n - 1    c1 = cv2.filter2D(img**2, -1, mask / n1, borderType=cv2.BORDER_REFLECT)    c2 = cv2.filter2D(img, -1, mask, borderType=cv2.BORDER_REFLECT)**2 / (n * n1)    sig = np.sqrt(np.maximum(c1 - c2, 0))    return sig

localmean函数

def localmean(img, mask):    lm = cv2.filter2D(        img, -1, mask / mask.sum(),        borderType=cv2.BORDER_REPLICATE)    return lm

二值化函数

def img_binary(img, w_size=3, w_sig=0.9, w_lm=0.9):    if len(img.shape) != 2:        img = cv2.cvtColor(img, cv2.COLOR_RGB2GRAY)    img = img / 255.0    mask = np.ones(w_size)    sig = stdfilt(img, mask)    if w_lm == 0:        w_lm = 1        lm = np.mean(img)    else:        lm = localmean(img, mask)    img = 255 * ((img > sig * w_sig) & (img > w_lm * lm))    return img

二值化

if __name__ == '__main__':    #False表示读取为灰度图...    img = cv2.imread(filepath, False)    img = img_binary(img, w_size=3, w_sig=0.9, w_lm=0.9)

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