| 摘要 |
PCT No. PCT/GB93/01352 Sec. 371 Date Jan. 17, 1995 Sec. 102(e) Date Jan. 17, 1995 PCT Filed Jun. 29, 1993 PCT Pub. No. WO94/00951 PCT Pub. Date Jan. 6, 1994Video signals are coded at a first relatively low frame rate. One or more portions of the image area, for example, the mouth of a person speaker: recognised by feature extractor, are coded at a higher frame rate. Preferably the second coding operates by resolving the pixel values of the image portion-considered as a vector-relative to a set or orthogonal reference vectors to produce coefficients which are then transmitted. Preferably, the feature extractor normalises the image portion as regards scaling, position and rotation and sends data on these parameters as side information. |
