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camera

CameraHandler #

Camera handler.

Handle camera initialization, sample detection.

Source code in cogip/tools/beaconcam/camera.py 
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class CameraHandler:
    """
    Camera handler.

    Handle camera initialization, sample detection.
    """

    _camera_device: Path = None  # Camera device
    _camera_codec: VideoCodec = None  # Video codec
    _camera_frame_width: int = None  # Camera frame width
    _camera_frame_height: int = None  # Camera frame height
    _camera_capture: cv2.VideoCapture = None  # OpenCV video capture
    _last_frame: SharedMemory = None  # Last generated frame to stream on web server
    _frame_rate: float = 6  # Number of images processed by seconds
    _exiting: bool = False  # Exit requested if True

    def __init__(self):
        """
        Class constructor.

        Create SocketIO client and connect to server.
        """
        self.settings = Settings()
        signal.signal(signal.SIGTERM, self.exit_handler)

        self.record_filename: Path | None = None
        self.record_writer: cv2.VideoWriter | None = None

        self.sio = socketio.Client(logger=False, engineio_logger=False)
        self.register_sio_events()
        Thread(
            target=lambda: polling2.poll(
                self.sio_connect,
                step=1,
                ignore_exceptions=(socketio.exceptions.ConnectionError),
                poll_forever=True,
            )
        ).start()

    @staticmethod
    def exit_handler(signum, frame):
        """
        Function called when TERM signal is received.
        """
        CameraHandler._exiting = True
        raise ExitSignal()

    def sio_connect(self) -> bool:
        """
        Connect to SocketIO server.
        Returning True stops polling for connection to succeed.
        """
        if self._exiting:
            return True

        self.sio.connect(str(self.settings.socketio_server_url), namespaces=["/beaconcam"])
        return True

    def open_camera(self):
        """
        Initialize camera and aruco markers detection parameters.
        """
        self._camera_capture = cv2.VideoCapture(str(self.settings.camera_device), cv2.CAP_V4L2)
        if not self._camera_capture.isOpened():
            logger.error(f"Camera handler: Cannot open camera device {self.settings.camera_device}")
            self._camera_capture.release()
            self._camera_capture = None
            return

        fourcc = cv2.VideoWriter_fourcc(*self.settings.camera_codec.value)
        ret = self._camera_capture.set(cv2.CAP_PROP_FOURCC, fourcc)
        if not ret:
            logger.warning(f"Video codec {self.settings.camera_codec} not supported")
            self.settings.camera_codec = None

        ret = self._camera_capture.set(cv2.CAP_PROP_FRAME_WIDTH, self.settings.camera_width)
        if not ret:
            logger.warning(f"Frame width {self.settings.camera_width} not supported")
            self.settings.camera_width = None

        ret = self._camera_capture.set(cv2.CAP_PROP_FRAME_HEIGHT, self.settings.camera_height)
        if not ret:
            logger.warning(f"Frame height {self.settings.camera_height} not supported")
            self.settings.camera_height = None

    def close_camera(self) -> None:
        """
        Release camera device.
        """
        if self._camera_capture:
            try:
                self._camera_capture.release()
                logger.info("Camera handler: Camera closed.")
            except Exception as exc:  # noqa
                logger.info("Camera handler: Failed to release camera: {exc}")

        self._camera_capture = None

    def open_last_frame(self, size: int) -> None:
        """
        Open the shared memory used to exchange last frame with the server.

        Arguments:
            size: Size of the shared memory
        """
        if not self._last_frame:
            try:
                self._last_frame = SharedMemory(name="last_frame", create=True, size=size)
                logger.info("Camera handler: shared memory for last_frame created.")
            except FileExistsError as exc:
                logger.warning(f"Camera handler: Failed to create shared memory for last_frame: {exc}")
                self._last_frame = None

    def close_last_frame(self) -> None:
        """
        Close last frame shared memory.
        """
        if self._last_frame:
            try:
                self._last_frame.close()
                self._last_frame.unlink()
                logger.info("Camera handler: Shared memory for last frame closed.")
            except Exception as exc:
                logger.info(f"Camera handler: Failed to close shared memory for last frame: {exc}")

        self._last_frame = None

    def camera_handler(self) -> None:
        """
        Read and process frames from camera.
        """
        interval = 1.0 / self._frame_rate

        try:
            while not self._exiting:
                start = time.time()

                if not self._camera_capture:
                    self.open_camera()

                if not self._camera_capture:
                    logger.warning("Camera handler: Failed to open camera, retry in 1s.")
                    sleep(1)
                    continue

                try:
                    self.process_image()
                except ExitSignal:
                    break
                except Exception as exc:
                    logger.warning(f"Unknown exception: {exc}")
                    self.close_camera()
                    sleep(1)
                    continue

                now = time.time()
                duration = now - start
                if duration > interval:
                    logger.warning(f"Function too long: {duration} > {interval}")
                else:
                    wait = interval - duration
                    time.sleep(wait)

        except (KeyboardInterrupt, ExitSignal):
            pass

        logger.info("Camera handler: Exiting.")

        self.close_last_frame()
        self.close_camera()
        if self.sio.connected:
            self.sio.disconnect()

    def process_image(self) -> None:
        """
        Read one frame from camera, process it, send samples to cogip-server
        and generate image to stream.
        """
        image_color: np.ndarray
        ret, image_color = self._camera_capture.read()
        if not ret:
            raise Exception("Camera handler: Cannot read frame.")

        image_stream: np.ndarray = image_color

        # Encode the frame in BMP format (larger but faster than JPEG)
        encoded_image: np.ndarray
        ret, encoded_image = cv2.imencode(".bmp", image_stream)

        if not ret:
            raise Exception("Can't encode frame.")

        frame = encoded_image.tobytes()
        self.open_last_frame(len(frame))

        if self._last_frame:
            self._last_frame.buf[0 : len(frame)] = frame

        if self.record_writer:
            self.record_writer.write(image_stream)

    def start_video_record(self):
        if self.record_writer:
            self.stop_video_record()
        records_dir = Path.home() / "records"
        records_dir.mkdir(exist_ok=True)
        # Keep only 20 last records
        for old_record in sorted(records_dir.glob("*.mp4"))[:-20]:
            old_record.unlink()
        timestamp = datetime.now().strftime("%Y%m%d-%H%M%S")
        self.record_filename = records_dir / f"beacon_{timestamp}.mp4"

        logger.info(f"Start recording video in {self.record_filename}")
        self.record_writer = cv2.VideoWriter(
            str(self.record_filename),
            cv2.VideoWriter_fourcc(*"mp4v"),
            self._frame_rate,
            (self.settings.camera_width, self.settings.camera_height),
        )

    def stop_video_record(self):
        if self.record_writer:
            logger.info("Stop recording video")
            self.record_writer.release()
            self.record_filename = None
            self.record_writer = None

    def register_sio_events(self) -> None:
        @self.sio.event(namespace="/beaconcam")
        def connect():
            """
            Callback on server connection.
            """
            polling2.poll(lambda: self.sio.connected is True, step=0.2, poll_forever=True)
            logger.info("Camera handler: connected to server")
            self.sio.emit("connected", namespace="/beaconcam")

        @self.sio.event(namespace="/beaconcam")
        def connect_error(data):
            """
            Callback on server connection error.
            """
            logger.info("Camera handler: connection to server failed.")

        @self.sio.event(namespace="/beaconcam")
        def disconnect():
            """
            Callback on server disconnection.
            """
            logger.info("Camera handler: disconnected from server")

        @self.sio.on("start_video_record", namespace="/beaconcam")
        def start_video_record():
            self.start_video_record()

        @self.sio.on("stop_video_record", namespace="/beaconcam")
        def stop_video_record():
            self.stop_video_record()

__init__() #

Class constructor.

Create SocketIO client and connect to server.

Source code in cogip/tools/beaconcam/camera.py 
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def __init__(self):
    """
    Class constructor.

    Create SocketIO client and connect to server.
    """
    self.settings = Settings()
    signal.signal(signal.SIGTERM, self.exit_handler)

    self.record_filename: Path | None = None
    self.record_writer: cv2.VideoWriter | None = None

    self.sio = socketio.Client(logger=False, engineio_logger=False)
    self.register_sio_events()
    Thread(
        target=lambda: polling2.poll(
            self.sio_connect,
            step=1,
            ignore_exceptions=(socketio.exceptions.ConnectionError),
            poll_forever=True,
        )
    ).start()

camera_handler() #

Read and process frames from camera.

Source code in cogip/tools/beaconcam/camera.py 
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def camera_handler(self) -> None:
    """
    Read and process frames from camera.
    """
    interval = 1.0 / self._frame_rate

    try:
        while not self._exiting:
            start = time.time()

            if not self._camera_capture:
                self.open_camera()

            if not self._camera_capture:
                logger.warning("Camera handler: Failed to open camera, retry in 1s.")
                sleep(1)
                continue

            try:
                self.process_image()
            except ExitSignal:
                break
            except Exception as exc:
                logger.warning(f"Unknown exception: {exc}")
                self.close_camera()
                sleep(1)
                continue

            now = time.time()
            duration = now - start
            if duration > interval:
                logger.warning(f"Function too long: {duration} > {interval}")
            else:
                wait = interval - duration
                time.sleep(wait)

    except (KeyboardInterrupt, ExitSignal):
        pass

    logger.info("Camera handler: Exiting.")

    self.close_last_frame()
    self.close_camera()
    if self.sio.connected:
        self.sio.disconnect()

close_camera() #

Release camera device.

Source code in cogip/tools/beaconcam/camera.py 
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def close_camera(self) -> None:
    """
    Release camera device.
    """
    if self._camera_capture:
        try:
            self._camera_capture.release()
            logger.info("Camera handler: Camera closed.")
        except Exception as exc:  # noqa
            logger.info("Camera handler: Failed to release camera: {exc}")

    self._camera_capture = None

close_last_frame() #

Close last frame shared memory.

Source code in cogip/tools/beaconcam/camera.py 
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def close_last_frame(self) -> None:
    """
    Close last frame shared memory.
    """
    if self._last_frame:
        try:
            self._last_frame.close()
            self._last_frame.unlink()
            logger.info("Camera handler: Shared memory for last frame closed.")
        except Exception as exc:
            logger.info(f"Camera handler: Failed to close shared memory for last frame: {exc}")

    self._last_frame = None

exit_handler(signum, frame) staticmethod #

Function called when TERM signal is received.

Source code in cogip/tools/beaconcam/camera.py 
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@staticmethod
def exit_handler(signum, frame):
    """
    Function called when TERM signal is received.
    """
    CameraHandler._exiting = True
    raise ExitSignal()

open_camera() #

Initialize camera and aruco markers detection parameters.

Source code in cogip/tools/beaconcam/camera.py 
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def open_camera(self):
    """
    Initialize camera and aruco markers detection parameters.
    """
    self._camera_capture = cv2.VideoCapture(str(self.settings.camera_device), cv2.CAP_V4L2)
    if not self._camera_capture.isOpened():
        logger.error(f"Camera handler: Cannot open camera device {self.settings.camera_device}")
        self._camera_capture.release()
        self._camera_capture = None
        return

    fourcc = cv2.VideoWriter_fourcc(*self.settings.camera_codec.value)
    ret = self._camera_capture.set(cv2.CAP_PROP_FOURCC, fourcc)
    if not ret:
        logger.warning(f"Video codec {self.settings.camera_codec} not supported")
        self.settings.camera_codec = None

    ret = self._camera_capture.set(cv2.CAP_PROP_FRAME_WIDTH, self.settings.camera_width)
    if not ret:
        logger.warning(f"Frame width {self.settings.camera_width} not supported")
        self.settings.camera_width = None

    ret = self._camera_capture.set(cv2.CAP_PROP_FRAME_HEIGHT, self.settings.camera_height)
    if not ret:
        logger.warning(f"Frame height {self.settings.camera_height} not supported")
        self.settings.camera_height = None

open_last_frame(size) #

Open the shared memory used to exchange last frame with the server.

Parameters:

Name Type Description Default
size int

Size of the shared memory

 required
Source code in cogip/tools/beaconcam/camera.py 
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def open_last_frame(self, size: int) -> None:
    """
    Open the shared memory used to exchange last frame with the server.

    Arguments:
        size: Size of the shared memory
    """
    if not self._last_frame:
        try:
            self._last_frame = SharedMemory(name="last_frame", create=True, size=size)
            logger.info("Camera handler: shared memory for last_frame created.")
        except FileExistsError as exc:
            logger.warning(f"Camera handler: Failed to create shared memory for last_frame: {exc}")
            self._last_frame = None

process_image() #

Read one frame from camera, process it, send samples to cogip-server and generate image to stream.

Source code in cogip/tools/beaconcam/camera.py 
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def process_image(self) -> None:
    """
    Read one frame from camera, process it, send samples to cogip-server
    and generate image to stream.
    """
    image_color: np.ndarray
    ret, image_color = self._camera_capture.read()
    if not ret:
        raise Exception("Camera handler: Cannot read frame.")

    image_stream: np.ndarray = image_color

    # Encode the frame in BMP format (larger but faster than JPEG)
    encoded_image: np.ndarray
    ret, encoded_image = cv2.imencode(".bmp", image_stream)

    if not ret:
        raise Exception("Can't encode frame.")

    frame = encoded_image.tobytes()
    self.open_last_frame(len(frame))

    if self._last_frame:
        self._last_frame.buf[0 : len(frame)] = frame

    if self.record_writer:
        self.record_writer.write(image_stream)

sio_connect() #

Connect to SocketIO server. Returning True stops polling for connection to succeed.

Source code in cogip/tools/beaconcam/camera.py 
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def sio_connect(self) -> bool:
    """
    Connect to SocketIO server.
    Returning True stops polling for connection to succeed.
    """
    if self._exiting:
        return True

    self.sio.connect(str(self.settings.socketio_server_url), namespaces=["/beaconcam"])
    return True