图像转灰度

• 公式：gray = 0.299r + 0.587g + 0.114b
• 代码

import cv2

IMG_PATH = '.\img\\'
IMG_SAVE = '.\save\\'
# lena = cv2.imread('lena.png', -1)
lena = IMG_PATH + 'lena.png'


def channel_split_by_func(file=lena):
    """BGR转Gray，自己手写计算灰度图，需要注意数字格式转换"""
    img = cv2.imread(file, -1)
    b, g, r = cv2.split(img)
    gray = (0.299*r + 0.587*g + 0.114*b).astype(np.uint8)
    cv2.imshow('b', b)
    cv2.imshow('g', g)
    cv2.imshow('r', r)
    cv2.imshow('ori', img)
    cv2.imshow('gray', gray)
    cv2.waitKey()
    cv2.destroyAllWindows()

def bgr2gray():
    """BGR转Gray，直接调用cv2函数"""
    color = cv2.imread(lena)
    gray = cv2.cvtColor(color, cv2.COLOR_BGR2GRAY)
    cv2.imshow('color', color)
    cv2.imshow('gray', gray)
    cv2.waitKey()
    cv2.destroyAllWindows()


if __name__ == '__main__':
    channel_split_by_func()