Spatial compression and decompression for video
US5675382A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 8, 1996 |
| Grant date | Oct 7, 1997 |
| Priority date | — |
| Expiry date | Apr 8, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A spatial compression and decompression system for color video data wherein a video stream is generated by a charge-coupled device with red, green and blue pixel elements. In a first compression stage, the 5-bit color data from each element is processed in turn. This step involves reading out from a lookup memory a 3-bit category (or compressed value) and 5-bit output value based on the 5-bit color data, a 5-bit previous value that represents same color data for a neighboring pixel and a 1-bit table select signal that determines in which of two similar tables the lookup is performed. The 3-bit category data for a pixel's three elements are combined and used as a 9-bit index into a Huffman table that performs the second stage of compression. Each Huffman table entry includes a variable-length Huffman code that represents more common categories with fewer bits, which provides additional compression over the first stage. The Huffman table reads out the code of the particular 9-bit category used for the lookup. This code is packed into an output buffer and transmitted to the decompressor that will unpack for display or store the resulting compressed data stream. In the first decompress…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.