Patent ID: 9137539
Filing Date: 2015-09-15
Classification: H04N

Abstract:
1. An image coding apparatus which codes a target picture having a bit-depth higher than a predetermined bit-depth, the bit-depth indicating an information capacity per pixel, the image coding apparatus comprising: a down-converter which generates a base layer picture by performing down-conversion on the target picture to reduce the bit-depth of the target picture by a first value so that the bit-depth of the target picture equals the predetermined bit-depth; a first encoder which codes the base layer picture, and generates a reconstructed picture by decoding the coded base layer picture; a subtractor which includes a shift amount determining unit configured to determine a second value based on characteristics of the base layer picture, the target picture, or the reconstructed picture, wherein the subtractor performs shift amount adjustment on the reconstructed picture to increase a bit-depth of the reconstructed picture by the second value, and generates, based on the reconstructed picture on which the shift amount adjustment has been performed and the target picture, an enhancement layer picture which is a picture for enhancing a quality of the base layer picture and has a same bit-depth as a bit-depth of the base layer picture; a second encoder which codes the enhancement layer picture; and a generating unit which generates the coded base layer picture, the coded enhancement layer picture, and a value corresponding to the second value determined by the shift amount determining unit.