立即学习:https://edu.csdn.net/course/play/26281/327071?utm_source=blogtoedu
1.OpenCV中，彩色图像缺省为BGR格式，颜色三通道顺序为B, G, R，分别对应索引0,1,2
2.OpenCV中，HSI/HSV颜色空间中H的取值范围是0-180，其他两个是0-255
3.HSV/HSI:V指的是RGB里面的最大的值，v = max(r,g,b);I是平均值，I=(r+g+b) / 3;
import cv2 as cv
filename= "d:/lena.jpg"
img=cv.imread(filename)
gray=cv.cvtColor(img, cv.COLOR_BGR2GRAY)
cv.imshow("source image!", img)
cv.imshow("gray image", gray)
cv.waitKey()
hsv = cv.cvtColor(img, cv.COLOR_BGR2HSV)
cv.imshow("hue", hsv[:,:,0])
cv.imshow("saturation", hsv[:,:,1])
cv.imshow("value", hsv[:,:,2])
cv.waitKey()
cv.imshow("blue", img[:,:,0])
cv.imshow("green", img[:,:,1])
cv.imshow("red", img[:,:,2])
cv.waitKey()
cv.destroyAllWindows()