### 將camera包裝成class
```python
class CameraCv(object):
    def __init__(self, videoSource=0):
        self.videoSource = videoSource
        self.camera = None
        self.cameraWidth = 0
        self.cameraHeight = 0
        self.cameraPreviewThreadHandle = None
        self.cameraPreviewThreadStopEvent = threading.Event()
        self.lastframeRGB = None
        self.latestFrame = None

    def start(self):
        print("Open Camera")
        self.camera = cv2.VideoCapture(self.videoSource, cv2.CAP_DSHOW)
        if not self.camera.isOpened():
            raise ValueError("Unable to open video source {}".format(self.videoSource))

        # Get video source width and height
        self.cameraWidth  = self.camera.get(cv2.CAP_PROP_FRAME_WIDTH)
        self.cameraHeight = self.camera.get(cv2.CAP_PROP_FRAME_HEIGHT)

        self.cameraPreviewThreadStopEvent.clear()
        self.cameraPreviewThreadHandle = threading.Thread(target=self.collectFrame, daemon=True, args=())
        self.cameraPreviewThreadHandle.start()

    def stop(self):
        print("Close Camera")
        self.cameraPreviewThreadStopEvent.set()
        if self.camera.isOpened():
            self.camera.release()
            cv2.destroyAllWindows()

    def collectFrame(self):
        while True:
            ret, frame = self.camera.read()
            if ret:
                # Return a boolean success flag and the current frame converted to BGR
                self.lastframeRGB = frame
                self.latestFrame = ImageTk.PhotoImage(image=Image.fromarray(cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)))

            if self.cameraPreviewThreadStopEvent.is_set():
                break

            time.sleep(0.016)

    def draw(self, container):
        if self.latestFrame is not None:
            container.imgtk = self.latestFrame
            container.configure(image=self.latestFrame)

    def read(self):
        return self.camera.read()

    def getLastFrameRgb(self):
        return self.lastframeRGB

    def saveFrame(self, filepath):
        cv2.imwrite(filepath, self.getLastFrameRgb())
```