Jetson Nano使用notebook实时显示CSI摄像头画面

Jetson nano 在使用CSI摄像头时，使用方法与Raspberry Pi有点出入
凌顺实验室（lingshunlab.com）分享的以下jutpterlab-notebook代码，实测可以实时显示摄像头画面在notebook上。

把一下代码复制到notebook上并运行：

# 查看摄像头信息
!v4l2-ctl -d 0 -l

# gstreamer信息生成
def gstreamer_pipeline(
    sensor_id=0,
    capture_width=1920,
    capture_height=1080,
    display_width=960,
    display_height=540,
    framerate=30,
    flip_method=0,
):
    return (
        "nvarguscamerasrc sensor-id=%d ! "
        "video/x-raw(memory:NVMM), width=(int)%d, height=(int)%d, framerate=(fraction)%d/1 ! "
        "nvvidconv flip-method=%d ! "
        "video/x-raw, width=(int)%d, height=(int)%d, format=(string)BGRx ! "
        "videoconvert ! "
        "video/x-raw, format=(string)BGR ! appsink"
        % (
            sensor_id,
            capture_width,
            capture_height,
            framerate,
            flip_method,
            display_width,
            display_height,
        )
    )

# 数据转换
def bgr8_to_jpeg(value, quality=10):
    return bytes(cv2.imencode('.jpg', value)[1])

class Camera(SingletonConfigurable):
    value = traitlets.Any()

    def __init__(self):
        try:
            self.cap = cv2.VideoCapture(gstreamer_pipeline(flip_method=0), cv2.CAP_GSTREAMER)

            re, image = self.cap.read()

            if not re:
                raise RuntimeError('Could not read image from camera.')

            self.value = image
            self.start()
        except:
            self.stop()
            raise RuntimeError(
                'Could not initialize camera.  Please see error trace.')

        atexit.register(self.stop)

    def _capture_frames(self):
        while True:
            re, image = self.cap.read()
            if re:
                self.value = image
            else:
                break    

    def start(self):
#         if not self.cap.isOpened():
#             self.cap.open(self._gst_str(), cv2.CAP_GSTREAMER)
        if not hasattr(self, 'thread') or not self.thread.isAlive():
            self.thread = threading.Thread(target=self._capture_frames)
            self.thread.start()

    def stop(self):
        if hasattr(self, 'cap'):
            self.cap.release()
        if hasattr(self, 'thread'):
            self.thread.join()

# 把摄像头画面显示在notebook上
image = widgets.Image(format='jpeg', width=500, height=500)  # this width and height doesn't necessarily have to match the camera

camera = Camera()

traitlets.dlink((camera, 'value'), (image, 'value'), transform=bgr8_to_jpeg)

display(image)

# 关闭摄像头
camera.stop()