epipolar geometry

The geometric relationship between two camera views that constrains a matching point to lie on a single line.

Epipolar geometry describes the rigid relationship between two camera views of the same scene: for a point $\mathbf{x}$ in one image, its true match in the other image is constrained to lie on a single epipolar line, computed from the fundamental or essential matrix -- collapsing a stereo correspondence search from an entire image down to one line. See the epipolar constraint.

Examples

Once the fundamental matrix is known, searching for a match to a point in image A collapses from scanning all of image B down to scanning a single line in it.