python改变单通道图片的像素值

这段代码用于多类分割处理掩码图片，在深度学习中，如果有三类分割，需要将标签设置为0，1，2

#改变图片像素值164-1；255-2；
from PIL import Image
import cv2
import os
# img = cv2.imread("F:/AI/glaucoma_set/gla_img_120_Chall/Annotation-Training400/Disc_Cup_Fovea_Illustration/g0001.jpg")
# img = cv2.imread("F:/AI/glaucoma_set/gla_img_120_Chall/Annotation-Training400/Disc_Cup_Masks/Non-Glaucoma_512/n0001.bmp",cv2.IMREAD_UNCHANGED)  # 读取系统的内照片

def change_pixel(img):
    width = img.shape[0]  # 长度
    height = img.shape[1]  # 宽度
    for i in range(0, width):  # 遍历所有长度的点
        for j in range(0, height):  # 遍历所有宽度的点
            if (img[i, j] == 164):
                img[i, j] = 1
            elif (img[i, j] == 255):
                img[i, j] = 2
            else:
                img[i, j] = 0
    return img
if __name__ =="__main__":
    filePath = 'F:/AI/glaucoma_set/gla_img_120_Chall/Annotation-Training400/Disc_Cup_Masks/Glaucoma_512/'
    savePath = 'F:/AI/glaucoma_set/gla_img_120_Chall/Annotation-Training400/Disc_Cup_Masks/Glaucoma_512_012/'
    name = os.listdir(filePath)
    for i in name:
        image_path = os.path.join(filePath,i)
        image_save_Path = os.path.join(savePath,i)
        image = cv2.imread(image_path, cv2.IMREAD_ANYCOLOR)
        img = change_pixel(image)
        cv2.imwrite(image_save_Path, img)