OpenCV图像处理基本操作详解

import cv2#opencv 的读取格式是BGR
import matplotlib.pyplot as plt
import numpy as np

#图像的显示，也可以创建多个窗口
img=cv2.imread("tu.jpg")
cv2.imshow("name",img)
#等待时间毫秒级，0表示任意键终止
cv2.waitKey(0)
cv2.destroyAllWindows()

#颜色通道提取
b,g,r=cv2.split(img)
print(b)
print(b.shape)
#颜色通道融合
img=cv2.merge((b,g,r))
print(img.shape)
#可以将其余两通道全部置零，保留一个颜色通道
cur_img=img.copy()
cur_img[:,:,0]=0#BRG
cur_img[:,:,1]=0
cv2.imshow("cur_img",cur_img)

top_size,bottom_size,left_size,right_size=(50,50,50,50)
replicate=cv2.copyMakeBorder(img,top_size,bottom_size,left_size,right_size,borderType=cv2.BORDER_REPLICATE)
reflect=cv2.copyMakeBorder(img,top_size,bottom_size,left_size,right_size,borderType=cv2.BORDER_REFLECT)
reflect101=cv2.copyMakeBorder(img,top_size,bottom_size,left_size,right_size,borderType=cv2.BORDER_REFLECT_101)
wrap=cv2.copyMakeBorder(img,top_size,bottom_size,left_size,right_size,borderType=cv2.BORDER_WRAP)
constant=cv2.copyMakeBorder(img,top_size,bottom_size,left_size,right_size,borderType=cv2.BORDER_CONSTANT,value=0)

#将图片画出对比
plt.subplot(231),plt.imshow(img,"gray"),plt.title("GRIGNAAL")
plt.subplot(232),plt.imshow(replicate,"gray"),plt.title("replicate")
plt.subplot(233),plt.imshow(reflect,"gray"),plt.title("reflect")
plt.subplot(234),plt.imshow(wrap,"gray"),plt.title("wrap")
plt.subplot(235),plt.imshow(constant,"gray"),plt.title("constant")
plt.show()

#视频的读取 cv2.VideoCapture 可以捕获摄像头，用数字来捕获不同设备，列如0,1 如果是视频文件直接指定好路径即可
vc=cv2.VideoCapture("IMG_1972.mp4")
#检测是否打开正确
if vc.isOpened():
 open,frame=vc.read()
else:
 open=False

while open:#一帧一帧的处理为灰色
 ret,frame=vc.read()
 if frame is None:
 break
 if ret==True:
 gray=cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) #一帧一帧的处理为灰色
 cv2.imshow("result",gray)
 if cv2.waitKey(100) & 0xFF==27:
  break
vc.release()
cv2.destroyAllWindows()