code: def essential_from_Rt(
      R1: torch.Tensor,
      t1: torch.Tensor,
      R2: torch.Tensor,
      t2: torch.Tensor,
  ) -> torch.Tensor:
      r"""Get the Essential matrix from Camera motion (Rs and ts).
  
      Reference: Hartley/Zisserman 9.6 pag 257 (formula 9.12)
  
      Args:
          R1: The first camera rotation matrix with shape :math:`(*, 3, 3)`.
          t1: The first camera translation vector with shape :math:`(*, 3, 1)`.
          R2: The second camera rotation matrix with shape :math:`(*, 3, 3)`.
          t2: The second camera translation vector with shape :math:`(*, 3, 1)`.
  
      Returns:
          The Essential matrix with the shape :math:`(*, 3, 3)`.
      """
      if not (len(R1.shape) >= 2 and R1.shape[-2:] == (3, 3)):
          raise AssertionError(R1.shape)
      if not (len(t1.shape) >= 2 and t1.shape[-2:] == (3, 1)):
          raise AssertionError(t1.shape)
      if not (len(R2.shape) >= 2 and R2.shape[-2:] == (3, 3)):
          raise AssertionError(R2.shape)
      if not (len(t2.shape) >= 2 and t2.shape[-2:] == (3, 1)):
          raise AssertionError(t2.shape)
  
      # first compute the camera relative motion
      R, t = relative_camera_motion(R1, t1, R2, t2)
  
      # get the cross product from relative translation vector
      Tx = cross_product_matrix(t[..., 0])
  
      return Tx @ R
  
file_path: kornia/kornia/geometry/epipolar/essential.py
imports: from typing import Optional, Tuple
  import torch
  import kornia.geometry.epipolar
  from kornia.core import eye, ones_like, stack, where, zeros
  from kornia.core.check import KORNIA_CHECK, KORNIA_CHECK_SAME_SHAPE, KORNIA_CHECK_SHAPE
  from kornia.geometry import solvers
  from kornia.utils import eye_like, vec_like
  from kornia.utils.helpers import _torch_svd_cast
  from .numeric import cross_product_matrix
  from .projection import depth_from_point, projection_from_KRt
  from .triangulation import triangulate_points
label_desc: Use image node_id 4 for calling a global function with example usage: essential_from_Rt(R1, t1, R2, t2) and returns: unknown