def get_image(self) -> np.ndarray:
        """Get the drawn image. The format is RGB.

        Returns:
            np.ndarray: the drawn image which channel is RGB.
        """
        assert self._image is not None, 'Please set image using `set_image`'
        if self.backend == 'matplotlib':
            return super().get_image()
        else:
            return self._image
Get the drawn image. The format is RGB.

        Returns:
            np.ndarray: the drawn image which channel is RGB.
        
mmpose/mmpose/visualization/opencv_backend_visualizer.py