python读取像素

1.

>>> from PIL import Image 
>>> lena = Image.open("/data/lena.jpg") 
>>> lena_L =lena.convert("L") 
>>> lena_L_rgb =lena_L.convert("RGB") 
>>>lena.getpixel((0,0)) (197, 111, 78) 
>>>lena_L.getpixel((0,0)) 132 
>>>lena_rgb.getpixel((0,0)) (132, 132, 132)

import cv2
import numpy as np
def salt(img, n):
    for k in range(n):
        i = int(np.random.random() * img.shape[1])
        j = int(np.random.random() * img.shape[0])
        if img.ndim == 2:
            img[j,i] = 255
        elif img.ndim == 3:
            img[j,i,0]= 0
            img[j,i,1]= 0
            img[j,i,2]= 0
    return img

if __name__ == '__main__':
    img = cv2.imread("test1.jpg")   

  h, w = source.shape[:2]  #彩色图像显示图像的大小

  saltImage = salt(img, 1000) cv2.imshow("Salt", saltImage) cv2.waitKey(0) cv2.destroyAllWindows()