Essential matrix
In computer vision, the essential matrix is a 3 × 3 {\displaystyle 3\times 3} matrix, E {\displaystyle \mathbf {E} } that relates corresponding points in stereo images assuming that the cameras satisfy the pinhole camera model. == Function == More specifically, if y {\displaystyle \mathbf {y} } and y ′ {\displaystyle \mathbf {y} '} are homogeneous normalized image coordinates in image 1 and 2, respectively, then ( y ′ ) ⊤ E y = 0 {\displaystyle (\mathbf {y} ')^{\top }\,\mathbf {E} \,\mathbf {y} =0} if y {\displaystyle \mathbf {y} } and y ′ {\displaystyle \mathbf {y} '} correspond to the same 3D point in the scene (not an "if and only if" due to the fact that points that lie on the same epipolar line in the first image will get mapped to the same epipolar line in the second image).