中值滤波处理椒盐噪声

    import cv2 as cv
    import numpy as np
    
    
    def noise(img,snr):
    h=img.shape[0]
    w=img.shape[1]
    img1=img.copy()
    sp=h*w
    NP=int(sp*(1-snr))
    for i in range (NP):
        randx=np.random.randint(1,h-1)   # random
        randy=np.random.randint(1,w-1)
        if np.random.random()<=0.5:
            img1[randx,randy]=0
        else:
            img1[randx,randy]=255
    return img1
    
    def mid(img):
    imgInfo = img.shape
    height = imgInfo[0]
    width = imgInfo[1]
    dst = np.empty_like(img, dtype=np.uint8)
    for i in