方法1 cv2.cvtColor(image, cv2.COLOR_BGR2RGB || cv2.COLOR_RGB2BGR)
import cv2
frame = cv2.imread("test.jpg")
RGBFrame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
BGRFrame = cv2.cvtColor(RGBFrame, cv2.COLOR_RGB2BGR)
方法2 numpy
# BGR to RGB
rgb = bgr[...,::-1]
# RGB to BGR 0->2 1->0 2->1
gbr = rgb[...,[2,0,1]]