Efficient motion estimation for an arbitrarily-shaped object
US6483874B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1999 |
| Grant date | Nov 19, 2002 |
| Priority date | — |
| Expiry date | Jan 27, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/543
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An efficient motion estimation technique for an arbitrarily-shaped video object reduces the number of searches for motion estimation for shape coding and texture coding. The technique can be easily employed in an MPEG-4 encoder for coding Video Object Planes (VOPs). In a pixel loop, an m×m block traverses a reference video image with the video object, and the alpha plane value of each pixel is examined. If the alpha plane values in a block are not all the same, this indicates the block overlaps the object boundary. Accordingly, a shape coding mask value for the coordinate of a reference pixel in the block, such as the top, left pixel, is set to “1”. As the block traverses the reference video image, a shape coding mask that generally follows the shape of the object boundary is developed to define a shaped reference image search area. A texture coding mask is defined similarly when the blocks overlap or are inside the object. When the same search range is used for both shape and texture motion estimation, the texture coding mask can be defined by ORing the shape coding mask with any blocks inside the object but not already included in the shape coding mask.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.