def K(self):
        """
        Get the intrinsic matrix for the Camera object.

        Returns
        -----------
        K : (3, 3) float
          Intrinsic matrix for camera
        """
        K = np.eye(3, dtype=np.float64)
        K[0, 0] = self.focal[0]
        K[1, 1] = self.focal[1]
        K[0, 2] = self.resolution[0] / 2.0
        K[1, 2] = self.resolution[1] / 2.0
        return K
Get the intrinsic matrix for the Camera object.

        Returns
        -----------
        K : (3, 3) float
          Intrinsic matrix for camera