System and method for matching blocks in a sequence of images
US5974192A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | May 6, 1996 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | May 6, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/10016
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Blocks in frames of a video are matched to similar blocks across frames using qualitative characteristics of the pixels in the block. Pixels in a frame are categorized into two or more categories. In one embodiment, three pixel categories are: 1) quasi-constant (QC) pixels having intensity values that vary slowly (e.g., pictorial portions), 2) textured pixels characterized by many small edges and thin-line signals (e.g., texture portions), and 3) dominant-edge (DE) pixels characterized by few sharp and dominant edges (e.g., edge portions). Blocks in different frames are matched by minimizing a cost function that measures the mismatch between a block in a first frame and a plurality of candidate blocks in a second frame. In one embodiment, a cost function comprises a contrast component and a brightness component. The brightness component is determined as a function of the pixel categories. Block matching in sequential frames of a video enables a calculation of displacement or motion estimation in the video. Motion estimation is used, for example, in video compression to encode a reference frame and subsequent displacements of blocks in the frame. The present block-matching invention…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.