OpenCV: Computer Vision Projects with Python

Interacting with a live video stream

Let's see how we can use the mouse to interact with live video stream from the webcam. We can use the mouse to select a region and then apply the "negative film" effect on that region, as shown next:

In the following program, we will capture the video stream from the webcam, select a region of interest with the mouse, and then apply the effect:

import cv2 import numpy as np def draw_rectangle(event, x, y, flags, params): global x_init, y_init, drawing, top_left_pt, bottom_right_pt if event == cv2.EVENT_LBUTTONDOWN: drawing = True x_init, y_init = x, y elif event == cv2.EVENT_MOUSEMOVE: if drawing: top_left_pt = ...