Image encoding apparatus sensitive to tone variations
US5414527A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 1992 |
| Grant date | May 9, 1995 |
| Priority date | — |
| Expiry date | Aug 13, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/91
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An encoding system which prevents deterioration of a picture quality and provides a high encoding efficiency even when the size of a block is increased to enhance an encoding efficiency. An input image which is divided into blocks by a blocking unit, is supplied to a plurality of encoders which perform encoding in different numbers of tone levels respectively. Respective pieces of encoded image information from the respective encoders are supplied in common to a selector. A block classification unit determines the degree of the tone gradient of an input block and then outputs the classification result to the selector. The selector, in accordance with the block classification result, selects one of the respective pieces of the encoded image information and outputs the selected one as selected encoded image information. For example, when the tone varies greatly, there is selected the encoder which has a small number of tone levels and a high resolution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.