Opencv cv2.cvtColor彩色图转灰度图

import os
import cv2
import queue
import threading
import numpy as np

#用户存取函数的返回值
q=queue.Queue()

def rgb2gray(image,method):
    h,w,c=image.shape
    gray=np.zeros((h,w),dtype=np.uint8)
    y=0
    for row in range(h):
        for col in range(w):
            #Opencv读取出的图片格式为BGR
            b,g,r=np.int32(image[row,col])

            if method==1:
                y=0.299*r+0.587*g+0.114*b
            if method==2:
                y=(max([r,g,b])+min([r,g,b]))//2
            if method==3:
                y=(r+g+b)//3
            if method==4:
                y=0.21*r+0.72*g+0.07*b
            if method==5:
                y=max([r,g,b])
            if method==6:
                y=min([r,g,b])
            gray[row,col]=y
    # return gray
    q.put((gray))


if __name__ == '__main__':
    print('Pycharm')
    curr_path=os.getcwd()+'\\5.jpg'
    print(curr_path)
    image=cv2.imread(curr_path)
    cv2.imshow('BGR: ',image)
    #opencv提供的转灰度图的方法
    gray_cvColor=cv2.cvtColor(image,cv2.COLOR_BGRA2GRAY)
    cv2.imshow('gray_cvColor',gray_cvColor)
    gray1=rgb2gray(image,1)
    gray2 = rgb2gray(image, 2)
    gray3 = rgb2gray(image, 3)
    gray4 = rgb2gray(image, 4)
    gray5 = rgb2gray(image, 5)
    gray6 = rgb2gray(image, 6)
    cv2.imshow('一般转换方法',gray1)
    cv2.imshow('亮度优化转换', gray2)
    cv2.imshow('平均亮度转换', gray3)
    cv2.imshow('权重亮度转换', gray4)
    cv2.imshow('最大亮度转换', gray5)
    cv2.imshow('最小亮度转换', gray6)

    cv2.waitKey(0)
    cv2.destroyAllWindows()