Editing Motion estimation (section)

{{Short description|Process used in video coding/compression}}
[[Image:Elephantsdream_vectorstill06.png|thumb|350px|Motion vectors that result from a movement into the <math>z</math>-plane of the image, combined with a lateral movement to the lower-right. This is a visualization of the motion estimation performed in order to compress an MPEG movie.]]

In [[computer vision]] and [[image processing]], '''motion estimation''' is the process of determining ''motion vectors'' that describe the transformation from one 2D image to another; usually from adjacent [[video frame|frames]] in a video sequence. It is an [[well-posed problem|ill-posed problem]] as the [[motion]] happens in three dimensions (3D) but the images are a projection of the 3D scene onto a 2D plane. The motion vectors may relate to the whole image (''global motion estimation'') or specific parts, such as rectangular blocks, arbitrary shaped patches or even per [[pixel]]. The motion vectors may be represented by a translational model or many other models that can approximate the motion of a real video camera, such as rotation and translation in all three dimensions and zoom.