Python OpenCV —— Modifying

　　一些索引和修改图像像素点数据等的操作，可打印观察运行结果。

# -*- coding: utf-8 -*-
"""
Created on Wed Sep 28 00:11:07 2016

@author: Administrator
"""

import cv2
import numpy as np
# length,588;width,468
img = cv2.imread('cute.jpg')

px = img[100,100]
print(px)

# accessing only blue pixel
# remember b,g,r
blue = img[100,100,0]
print(blue)

# modify the pixel
img[100,100] = [255,255,255]

# accesing RED value
p_item = img.item(10,10,2)

# modyfying RED value
pp_item = img.itemset((10,10,2),100)

# length width 3
p_shape = img.shape

# length*width*3
p_size = img.size

# data type
p_dtype = img.dtype

# Image ROI
# 将一块区域复制到另一区域
ball = img[280:340,330:390]
img[273:333,100:160] = ball
cv2.imshow('image',img)
k = cv2.waitKey(0)
if k == 27:
	cv2.destroyAllWindows()


# Splitting and Merging Image Channels
b,g,r = cv2.split(img)  # costly
img = cv2.merge((b,g,r))
b = img[:,:,0]  # blue

# make all the red pixels to zero
img[:,:,0] = 0