Compressed image noise removal device and reproduction device

1. An image data processing device, comprising:

a decoder device configured to effect:

a Variable Length Decoding (VLD) unit for decoding a digital-image-compressed stream into image data and sub information;

an inverse quantization unit for inversely quantizing said image data decoded by said VLD unit;

an inverse frequency transform unit for inversely frequency-transforming said inversely-quantized image data; and

a motion compensation unit for executing a motion compensation based on said sub information decoded by said VLD unit;

an information holding unit for holding said sub information by the amount of a plurality of blocks, said sub information being decoded by said VLD unit;

a noise judgment unit for making a judgment on whether noise removal is to be executed or not, for each block of a decoded image generated by said decoder device, and said information holding unit;

a noise removal unit for executing said noise removal of a block whose noise removal has been judged to be executed by said noise judgment unit, using said image data outputted from said inverse quantization unit, motion compensation data outputted from said motion compensation unit, and said sub information held in said information holding unit; and

a display-image holding unit for holding, as a display image, a decoded image after noise has been removed by said noise removal unit if said noise removal has been judged to be executed by said noise judgment unit, or said decoded image outputted from said decoder device if said noise removal has been judged not to be executed thereby, wherein

said noise removal by the noise removal unit being executed by correcting a coefficient for the decoded image outputted from the decoder device; and

said correction being executed within a range where coefficient value for the corrected decoded image becomes a coefficient value of the decoded image outputted from the decoder device when inverse-quantized using a quantization width included in said sub information.

2. The image data processing device according to claim 1 , wherein

a judgment as to whether or not to execute said noise removal is determined based on edge information and quantization values of said block whose noise removal has been judged to be executed.

3. The image data processing device according to claim 1 , wherein

correction values for said inversely-quantized coefficient values when said noise removal is executed are calculated using image data on an adjacent block, and

said adjacent block being adjacent to said block whose noise removal has been judged to be executed, and quantization values of said adjacent block being small.

4. The image data processing device according to claim 1 , wherein

said decoder device is a Motion Picture Experts Group 2 (MPEG2) decoder, where MPEG2 is an image-compression-dedicated international standard scheme.

5. The image data processing device according to claim 1 , wherein

said decoder device is an H.264 decoder, where H.264 is an image-compression-dedicated international standard scheme.