使用 Opencv 和 python 实时流上的鼠标单击事件

Question

i am new to opencv -python. I want to draw a rectangle in a live stream video captured from my webcam. While drawing the rectangle,the video must freeze. I am successful in drawing a rectangle on a image,but i don't know how to do the same on a live video using opencv and python . Please help..

Answer 1

This is a code that I'm using to draw a rectange in videos.

The code works like that:

1. click on video and the script save the start point
2. click again and the script save the end point and draw the rectangle

3. click again to start drawing another retangle

    import numpy as np import cv2 rect = (0,0,0,0) startPoint = False endPoint = False def on_mouse(event,x,y,flags,params): global rect,startPoint,endPoint # get mouse click if event == cv2.EVENT_LBUTTONDOWN: if startPoint == True and endPoint == True: startPoint = False endPoint = False rect = (0, 0, 0, 0) if startPoint == False: rect = (x, y, 0, 0) startPoint = True elif endPoint == False: rect = (rect[0], rect[1], x, y) endPoint = True cap = cv2.VideoCapture('../videos/sample.avi') waitTime = 50 #Reading the first frame (grabbed, frame) = cap.read() while(cap.isOpened()): (grabbed, frame) = cap.read() cv2.namedWindow('frame') cv2.setMouseCallback('frame', on_mouse) #drawing rectangle if startPoint == True and endPoint == True: cv2.rectangle(frame, (rect[0], rect[1]), (rect[2], rect[3]), (255, 0, 255), 2) cv2.imshow('frame',frame) key = cv2.waitKey(waitTime) if key == 27: break cap.release() cv2.destroyAllWindows()