US 2008/0165849 A1Published application

Image encoder and image decoder, image encoding method and image decoding method, image encoding program and image decoding program, and computer readable recording medium recorded with image encoding program and computer readable recording medium recorded with image decoding program

AssigneeMitsubishi Electric Corporation

InventorsYoshimi Moriya, Shunichi Sekiguchi, Kazuo Sugimoto, Yoshihisa Yamada, Koutarou Asai, Tokumichi Murakami, Yuichi Idehara

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Abstract

An image encoder including: a predicted-image generating unit that generates a predicted image in accordance with a plurality of prediction modes indicating predicted-image generating methods; a prediction-mode judging unit that evaluates prediction efficiency of a predicted image outputted from the predicted-image generating unit to judge a predetermined prediction mode; and an encoding unit that subjects an output of the prediction-mode judging unit to variable-length encoding. The prediction-mode judging unit judges, on the basis of a predetermined control signal, which one of a common prediction mode and a separate prediction mode is used for respective color components forming the input image signal, and multiplexes information on the control signal on a bit stream, multiplexes, when the common prediction mode is used, common prediction mode information on the bit stream, and multiplexes, when the common prediction mode is not used, prediction mode information for each of the color components on the bit stream.

Claims8

Dependent claims

An image decoder that decodes a color image signal based on an input of a bit stream generated by compression-encoding a color image which is formed of a plurality of color components, the color image being compression-encoded in units of regions obtained by dividing the color image into predetermined regions, the image decoder comprising:

a header analyzing unit that extracts color sampling format indication information and common encoding/independent encoding identification information from the bit stream;
a decoding unit that decodes, for each of the regions, a first intra-prediction mode used for a luminance component and a second intra-prediction mode used for the other color components, the first intra-prediction mode and the second intra-prediction mode being included in the bit stream, in a case where the color sampling format indication information indicates one of a 4:2:0 format and a 4:2:2 format, decodes the first intra-prediction mode corresponding to respective color components on the basis of the common encoding/independent encoding identification information, in a case where the color sampling format indication information indicates a 4:4:4 format, and decodes a prediction error signal for each of the regions;
a first predicted-image generating unit that generates a predicted image on the basis of the decoded first intra-prediction mode;
a second predicted-image generating unit that generates a predicted image on the basis of the decoded second intra-prediction mode;
and
an adding unit that generates a decoded image by adding the decoded prediction error signal and the predicted image, wherein the decoding unit decodes the first intra-prediction mode commonly used for all the color components, in a case where the common encoding/independent encoding identification information indicates that the regions serving as the units of encoding are encoded by a common prediction method for respective color components, and decodes the first intra-prediction mode in units of the regions for respective color components, in a case where the common encoding/independent encoding identification information indicates that the regions serving as the units of encoding are respectively encoded by a separate prediction method for respective color components, and inputs, to the adding unit, a predicted image generated by one of the first predicted-image generating unit and the second predicted-image generating unit on the basis of the color sampling format indication information.

3 more elements

An image encoder, comprising:

a predicted-image generating unit that generates a predicted image in accordance with a plurality of prediction modes indicating predicted-image generating methods, a plurality of reference image identification numbers, and a plurality of motion vectors;
a prediction-mode judging unit that evaluates prediction efficiency of a predicted image outputted from the predicted-image generating unit to judge a predetermined prediction mode, a predetermined reference image identification number, and predetermined motion vector;
and
an encoding unit that subjects an output of the prediction-mode judging unit to variable-length encoding, wherein
the prediction-mode judging unit judges, on the basis of a predetermined control signal, whether a common prediction mode, a common reference image identification number, and a common motion vector are used for respective color components forming an input image signal or a separate prediction mode, a separate reference image identification number, and a separate motion vector are used for each of the color components are used for the respective color components, multiplexes information on the control signal on the bit stream, multiplexes, when the common prediction mode, the common reference image identification number, and the common motion vector are used, common prediction mode information, the common reference image identification number, and the common motion vector on the bit stream, and multiplexes, when the common prediction mode, the common reference image identification number, and the common motion vector are not used, prediction mode information, the reference image identification number, and the motion vector for each of the color components on the bit stream.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/931,756Filed 31 Oct 2007
Priority: JP 2005 21260122 Jul 2005
Published: 10 Jul 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

H04N 19/157
Characterised by the element, parameter or criterion affecting or controlling the adaptive coding: assigned coding mode, i.e. the coding mode…
H04N 19/109
Selection of coding mode or of prediction mode: among a plurality of temporal predictive coding modes
H04N 19/11
Selection of coding mode or of prediction mode: among a plurality of spatial predictive coding modes
H04N 19/147
Data rate or code amount at the encoder output: according to rate distortion criteria