Python-opencv专栏（02）

太过爱你忘了你带给我的痛 2022-11-21 14:01 152阅读 0赞

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**时间比较**

# 记录循环轮数（为了计算时间）t1 #

t1 = cv2.getTickCount()  
inverse(img)

# 记录循环轮数（为了计算时间）t2 #

t2 = cv2.getTickCount()  
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通道颜色

#!/usr/bin/python3.6
    # -*- coding: utf-8 -*-
    # @Time    : 2020/11/1 21:04
    # @Author  : ptg
    # @Email   : zhxwhchina@163.com
    # @File    : course_02.py
    # @Software: PyCharm
    
    import cv2
    import numpy as np
    def access_piexl(image):
        print(image.shape)
        height = image.shape[0]
        width = image.shape[1]
        channel = image.shape[2]
        print("width:%s,height:%s,channels:%s" % (width, height, channel))
    
        for row in range(height):
            for col in range(width):
                for c in range(channel):
                    pv = image[row,col,c]
                    image[row,col,c ] = 255 - pv
        cv2.imshow("pixels_demo",image)
    
    # 尽量靠近opencv书写的API
    def inverse(image):
        dst = cv2.bitwise_not(image)
        cv2.imshow('dst',dst)
    
    
    def color_space_demo(image):
        gray = cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)
        hsv = cv2.cvtColor(image,cv2.COLOR_BGR2HSV)
        cv2.imshow('hsv',hsv)
        yuv = cv2.cvtColor(image,cv2.COLOR_BGR2YUV)
        cv2.imshow('yuv', yuv)
        ycrb = cv2.cvtColor(image,cv2.COLOR_BGR2YCR_CB)
        cv2.imshow('ycrb', ycrb)
    
    img = cv2.imread("lena.jpg")
    # 记录循环轮数（为了计算时间）t1
    t1 = cv2.getTickCount()
    inverse(img)
    # 记录循环轮数（为了计算时间）t2
    t2 = cv2.getTickCount()
    t = (t2 - t1)/cv2.getTickFrequency()*1000 #ms
    print("time:%s ms"%t)
    color_space_demo(img)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

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