一、遍歷訪問圖片每個畫素點，並修改相應的RGB

def access_pixels(image):
    print(image.shape)
    height = image.shape[0]
    width = image.shape[1]
    channels = image.shape[2]
    print("width: %s  height: %s  channels: %s"%(width, height, channels))
    for row in range(height):
        for col in range(width):
            for
 
 c in range(channels):
                pv = image[row , col, c]              #獲取每個畫素點的每個通道的數值
                image[row, col, c]=255 - pv           #灰度值是0-255   這裡是修改每個畫素點每個通道灰度值
    cv2.imshow("Reverse_phase_image",image)
    
if __name__ =="__main__":
    src=cv2.imread('555.png')                          #預設彩色讀入
 

    cv2.imshow('original_image', src)                  #顯示影象

    t1 = cv2.getTickCount()                            #GetTickcount函式返回從作業系統啟動到當前所經過的毫秒數
    access_pixels(src)
    t2 = cv2.getTickCount()
    time = (t2-t1)/cv2.getTickFrequency()              #getTickFrequency函式返回CPU的頻率,就是每秒的計時週期數
    print
 
("time : %s ms"%(time*1000) )                 #輸出執行時間
    cv2.waitKey(0)
    cv2.destroyAllWindows()