cvAffineCamera.py

import cv2
import numpy as np
import time

cap = cv2.VideoCapture(0)
spoints = []

def mouse_handler(event, x, y, flags, params):
    if event == cv2.EVENT_LBUTTONUP:
        if len(spoints) < 4:
            spoints.append([x, y])

cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 720)

cv2.namedWindow('img', cv2.WINDOW_NORMAL)
cv2.resizeWindow('img', (1080, 720))
cv2.setMouseCallback('img', mouse_handler)

M = None
while cap.isOpened():
    ret, frame = cap.read()
    if not ret:
        time.sleep(0.01)
        continue

    if M is None:
        for idx in range(len(spoints)):
            pt = tuple(spoints[idx])
            cv2.circle(frame, pt, 4, (255, ), -1)
            if idx > 0:
                ppt = tuple(spoints[idx-1])
                cv2.line(frame, ppt, pt, (255, ))
            if idx == len(spoints) - 1:
                pt0 = tuple(spoints[0])
                cv2.line(frame, pt, pt0, (255, ))
    else:
        frame = cv2.warpAffine(frame, M, (1080, 720))

    cv2.imshow('img', frame)

    key = cv2.waitKey(1)
    if key == 13:
        if M is None:
            spoints = np.float32(spoints)
            dpoints = np.float32([[0, 0], [0, 720], [1080, 720]])
            M = cv2.getAffineTransform(spoints, dpoints)
        else:
            M = 0
            spoints = []
    if key == 27:
        break