python opencv给视频添加矩形mask以及读取视频中的暂停和退出_python在视频上画矩形

以给视频中某个区域添加mask为例

import cv2
import numpy as np

def image_pre(img):
    # binary mask
    mask_threth = 50
    coordinates = [[[200, 150], [250, 150], [250, 350], [200, 350]]]
    coordinates = np.array(coordinates)
    mask = np.zeros(img.shape[:2], dtype=np.int8)
    mask = cv2.fillPoly(mask, coordinates, 255)
    bbox_mask = (mask > mask_threth).astype(np.uint8)

    # draw the masked image
    color_mask = np.random.randint(0, 256, (1, 3), dtype=np.uint8)
    color_mask = np.array([0, 0, 0], dtype=np.uint8)
    bbox_mask = bbox_mask.astype(np.bool)
    # img[bbox_mask] = img[bbox_mask] * 0.5 + color_mask * 0.5
    img[bbox_mask] = img[bbox_mask] * 0 + color_mask
    img = img[:, :, ::-1]

    return img

cap = cv2.VideoCapture('pedestrian/pedestrian.mp4')
fourcc = cv2.VideoWriter_fourcc(*'XVID')
fps =cap.get(cv2.CAP_PROP_FPS)
size = (int(cap.get(cv2.CAP_PROP_FRAME_WIDTH)), int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT)))
out = cv2.VideoWriter('pedestrian/pedestrian_mask.mp4',fourcc, fps, size)

while(cap.isOpened()):
    ret, frame = cap.read()
    if ret==True:
        # frame = cv2.flip(frame,0)
        frame = image_pre(frame)

        out.write(frame)

        cv2.imshow('frame',frame)

        # 按q退出
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break

        # 按s暂停，再按任意键继续
        if (cv2.waitKey(1) & 0xFF) == ord('s'):
            cv2.waitKey(0)
    else:
        break

cap.release()
out.release()
cv2.destroyAllWindows()
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