IMAGE ENCODING DEVICE, IMAGE DECODING DEVICE, IMAGE ENCODING METHOD AND IMAGE DECODING METHOD

• US 20090003717A1
• Filed: 10/30/2007
• Published: 01/01/2009
• Est. Priority Date: 06/28/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yamada, Yoshihisa, Asai, Kohtaro, Sekiguchi, Shunichi, Murakami, Tokumichi, Idehara, Yuichi, Moriya, Yoshimi, Yamagishi, Shuichi
• Granted Patent: US 7,991,237 B2
• Time in Patent Office: Days
• US Class Current: 382/238
• CPC Class Codes: H04N 19/107 between spatial and temporal predictive coding, e.g. picture refresh
• CPC Class Codes: H04N 19/109 among a plurality of temporal predictive coding modes
• CPC Class Codes: H04N 19/11 among a plurality of spatial predictive coding modes
• CPC Class Codes: H04N 19/117 Filters, e.g. for pre-processing or post-processing sub-band filter banks H04N19/635
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/19 using optimisation based on Lagrange multipliers
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/517 by encoding
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

An encoding device includes a color component separating unit for separating an input bit stream for the respective color components, a block dividing unit for dividing an input color component signal into blocks to generate a signal of an encoding unit area, a predicted image generating unit for generating a predicted image for the signal, a determining unit for determining a prediction mode used for encoding according to a prediction efficiency of the predicted image, a prediction error encoding unit for encoding a difference between the predicted image corresponding to the prediction mode determined by the determining unit and the input color component signal, and an encoding unit for variable length-coding the prediction mode, an output from the prediction error encoding unit, and a color component identification flag indicating the color component to which the input bit stream belongs as a result of the color component separation.

Claims

1. An image encoding device for receiving a color moving image signal composed of a plurality of color components as an input, dividing the color moving image signal into predetermined encoding unit areas for each of the plurality of color components, and using motion compensation prediction encoding to digitally compress the color moving image signal, comprising:

a color component separating unit for separating an input bit stream for each of the plurality of color components;

a block dividing unit for dividing an input color component signal into predetermined blocks to generate a signal of each of the encoding unit areas;

a predicted image generating unit for generating a predicted image for the signal of each of the encoding unit areas according to at least one motion compensation prediction mode indicating a motion compensation prediction image generating method and a motion vector;

a determining unit for determining a motion compensation prediction mode used for encoding and a corresponding motion vector according to a prediction efficiency of the motion compensation prediction image output from the predicted image generating unit;

a prediction error encoding unit for encoding a difference between the predicted image corresponding to the motion compensation prediction mode determined by the determining unit and the input color component signal; and

an encoding unit for variable length-coding the motion compensation prediction mode, the motion vector, an output from the prediction error encoding unit, and a color component identification flag indicating the color component to which the input bit stream belongs as a result of the color component separation, wherein;

the predicted image generating unit generates the predicted image for each of the encoding unit areas at an accuracy up to a designated accuracy of a virtual pixel based on virtual pixel accuracy indication information indicating an upper accuracy limit of the virtual pixel used for generating the predicted image;

the determining unit obtains the motion compensation prediction mode and the motion vector for each of the encoding unit areas at the accuracy up to the designated accuracy of the virtual pixel based on the virtual pixel accuracy indication information; and

the encoding unit multiplexes the virtual pixel accuracy indication information in the bit stream and encodes the motion vector for each of the encoding unit areas based on the virtual pixel accuracy indication information to multiplex information obtained by encoding the motion compensation prediction mode and the prediction error in the bit stream.