Encoding apparatus for hierarchically encoding image signal and decoding apparatus for decoding the image signal hierarchically encoded by the encoding apparatus
US5781561A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1996 |
| Grant date | Jul 14, 1998 |
| Priority date | — |
| Expiry date | Mar 15, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/30
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Important quantized coefficients having absolute values which are higher than a threshold value are extracted from each of quantized coefficient streams into which a digital image signal is transformed, and an important quantized coefficient stream composed of the important quantized coefficients and zero-valued quantized coefficients is produced on condition that the number of important quantized coefficients and zero-valued quantized coefficients is equal to that of quantized coefficients in each quantized coefficient stream and positions of the important quantized coefficients in the important quantized coefficient stream are the same as those in a corresponding quantized coefficient stream. Also, a lesser-important quantized coefficient stream is produced by subtracting the important quantized coefficient stream from the corresponding quantized coefficient stream. Stronger error correction codes are added to each important quantized coefficient stream and are transmitted to a decoding apparatus, and less-strong error correction codes are added to each lesser-important quantized coefficient stream and are transmitted to the decoding apparatus. Therefore, an image having a superi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.