Block-matching algorithm: Difference between revisions

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Revision as of 06:03, 2 December 2016

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Aa '''Block Matching Algorithm''' is a way of locating matching [[macroblock]]s in a sequence of [[digital video]] frames for the purposes of [[motion estimation]]. The underlying supposition behind motion estimation is that the patterns corresponding to objects and background in a frame of video sequence move within the frame to form corresponding objects on the subsequent frame. This can be used to discover temporal redundancy in the video sequence, increasing the effectiveness of inter-frame [[video compression]] by defining the contents of a macroblock by reference to the contents of a known macroblock which is minimally different.

[[File:Block-matching algorithm.png|thumb|405x405px]]

A block matching algorithm involves dividing the current [[Film frame|frame]] of a video into macroblocks and comparing each of the macroblocks with a corresponding block and its adjacent neighbors in a nearby frame of the video (sometimes just the previous one). A [[vector (mathematics and physics)|vector]] is created that models the movement of a macroblock from one ___location to another. This movement, calculated for all the macroblocks comprising a frame, constitutes the motion estimated in a frame.