code: def depth_from_point(R: Tensor, t: Tensor, X: Tensor) -> Tensor:
      r"""Return the depth of a point transformed by a rigid transform.
  
      Args:
         R: The rotation matrix with shape :math:`(*, 3, 3)`.
         t: The translation vector with shape :math:`(*, 3, 1)`.
         X: The 3d points with shape :math:`(*, 3)`.
  
      Returns:
         The depth value per point with shape :math:`(*, 1)`.
      """
      X_tmp = R @ X.transpose(-2, -1)
      X_out = X_tmp[..., 2, :] + t[..., 2, :]
      return X_out
  
file_path: kornia/kornia/geometry/epipolar/projection.py
imports: from typing import Tuple, Union
  import torch
  from torch.linalg import qr
  from kornia.core import Tensor, concatenate, ones_like, pad, stack, zeros_like
  from kornia.utils import eye_like, vec_like
  from kornia.utils.helpers import _torch_svd_cast
  from .numeric import cross_product_matrix
label_desc: Use image node_id 6 for calling a global function with example usage: depth_from_point(R, t, X) and returns: X_out