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我正在使用 piCamera 将视频从我的 raspberryPi 流式传输到网络套接字，以便我可以在本地网络中查看它。

我想从头开始制作自己的运动检测脚本，因此我想从视频流中获取第一张图像（这将是纯背景），然后与下一个帧到第一个帧的函数进行比较，以检查是否有东西改变了（我已经单独编写了这些函数），我并不真正担心这里的效率。

主要问题：我想从 BytesIO 对象中的这些帧中获取数据，然后将它们转换为 B&W 中的 2D numpy 数组，以便我可以执行操作。所有这一切都在保持流进行的同时（事实上，我已经将帧速率降低到每秒 4 帧，以使其在我的计算机上运行得更快）。

以下代码遇到的问题：我发现的问题之一是数字偏离了。在我的设置中，我的相机的分辨率约为 640*480（= 307,200 长度的黑白数组像素数据），而我在 len() 中的计算返回不到 100k 像素。

    def main():
    print('Initializing camera')
    base_image = io.BytesIO()
    image_captured = io.BytesIO()
    with picamera.PiCamera() as camera:
        camera.resolution = (WIDTH, HEIGHT)
        camera.framerate = FRAMERATE
        camera.vflip = VFLIP # flips image rightside up, as needed
        camera.hflip = HFLIP # flips image left-right, as needed
        sleep(1) # camera warm-up time
        print('Initializing websockets server on port %d' % WS_PORT)
        WebSocketWSGIHandler.http_version = '1.1'
        websocket_server = make_server(
            '', WS_PORT,
            server_class=WSGIServer,
            handler_class=WebSocketWSGIRequestHandler,
            app=WebSocketWSGIApplication(handler_cls=StreamingWebSocket))
        websocket_server.initialize_websockets_manager()
        websocket_thread = Thread(target=websocket_server.serve_forever)
        print('Initializing HTTP server on port %d' % HTTP_PORT)
        http_server = StreamingHttpServer()
        http_thread = Thread(target=http_server.serve_forever)
        print('Initializing broadcast thread')
        output = BroadcastOutput(camera)
        broadcast_thread = BroadcastThread(output.converter, websocket_server)
        print('Starting recording')
        camera.start_recording(output, 'yuv')

        try:
            print('Starting websockets thread')
            websocket_thread.start()
            print('Starting HTTP server thread')
            http_thread.start()
            print('Starting broadcast thread')
            broadcast_thread.start()
            time.sleep(0.5)

            camera.capture(base_image, use_video_port=True, format='jpeg')

            base_data = np.asarray(bytearray(base_image.read()), dtype=np.uint64)

            base_img_matrix = cv2.imdecode(base_data, cv2.IMREAD_GRAYSCALE)

            while True:
                camera.wait_recording(1)

                #insert here the code for frame analysis

                camera.capture(image_captured, use_video_port=True, format='jpeg')
                data_next = np.asarray(bytearray(image_captured.read()), dtype=np.uint64)
                next_img_matrix = cv2.imdecode(data_next, cv2.IMREAD_GRAYSCALE)

                monitor_changes(base_img_matrix, next_img_matrix)

        except KeyboardInterrupt:
            pass
        finally:
            print('Stopping recording')
            camera.stop_recording()
            print('Waiting for broadcast thread to finish')
            broadcast_thread.join()
            print('Shutting down HTTP server')
            http_server.shutdown()
            print('Shutting down websockets server')
            websocket_server.shutdown()
            print('Waiting for HTTP server thread to finish')
            http_thread.join()
            print('Waiting for websockets thread to finish')
            websocket_thread.join()


if __name__ == '__main__':
    main()
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1 回答 1

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解决了，基本上问题出在我处理数据和 BytesIO 文件的方式上。首先，我需要使用 unsigned int8 作为文件类型来解码 id。然后我切换到 np.frombuffer 来完整地读取文件，因为基本图像不会改变，因此它总是会读取相同的内容，并且下一个将在每个 while 循环中被初始化和消除。我也可以在函数中用 0 替换 cv2.IMREAD_GRAYSCALE。

camera.start_recording(output, 'yuv')
base_image = io.BytesIO()

    try:
        print('Starting websockets thread')
        websocket_thread.start()
        print('Starting HTTP server thread')
        http_thread.start()
        print('Starting broadcast thread')
        broadcast_thread.start()
        time.sleep(0.5)

        camera.capture(base_image, use_video_port=True, format='jpeg')

        base_data = np.frombuffer(base_image.getvalue(), dtype=np.uint8)

        base_img_matrix = cv2.imdecode(base_data, 0)

        while True:
            camera.wait_recording(0.25)
            image_captured = io.BytesIO()

            #insert here the code for frame analysis

            camera.capture(image_captured, use_video_port=True, format='jpeg')
            data_next = np.frombuffer(image_captured.getvalue(), dtype=np.uint8)
            next_img_matrix = cv2.imdecode(data_next, cv2.IMREAD_GRAYSCALE)

            monitor_changes(base_img_matrix, next_img_matrix)
            image_captured.close()
于 2020-03-20T11:21:31.573 回答