Method for filtering an image

Abstract

The present invention relates to a method for recovering a compressed image for an image processing technique and an apparatus therefor. In the present invention, a cost function is defined in consideration with a directional characteristic of the pixels which will be recovered and a plurality of pixels of the recovering pixels. In addition, a regularization parameter variable having a certain weight is obtained from the cost function, and the regularization parameter variable is approximated using the compressed pixel for thereby obtaining a recovering pixel. The regularization parameter variable has a weight of a reliability with respect to the original image and a weight of a smoothing degree of the original image.In the methods and apparatuses for filtering, a filtering method is selected from filtering methods having different filtering strengths based on whether a pixel being filleted is in an intra-coded portion of an image.

Description

DIVISIONAL REISSUE APPLICATIONS[0001]Notice: More than one reissue application has been filed for the reissue of U.S. Pat. No. 6,535,643. The reissue applications are application Ser. Nos. 11 / 081,073; 11 / 081,075; and 11 / 338,905 (the subject application).BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an image processing technique, and in particular to a method for recovering a compressed video signal and an apparatus therefor.[0004]2. Description of the Prior Art[0005]The image compression technique of MPEG, MPEG2, H261, H263, etc. is implemented by a Hybrid MC DCT (Motion Compensation Discrete Cosine Transform) technique. This hybrid MC DCT is classified into an encoding process and decoding processes. In the encoding process, the original image is divided into a plurality of blocks for compressing the information of a spacious region, and a two-dimensional DCT is performed with respect to each block, and a redundancy is decreased in...

AI Technical Summary

Benefits of technology

This approach effectively reduces block artifacts and ring effects in decoded video signals by adaptively filtering based on pixel differences and quantization parameters, enhancing image quality while maintaining computational efficiency.

Problems solved by technology

While the video signal is being coded, the information may be lost during the quantizing process.

Therefore, the video signals reconstructed by the decoder may cause blocking artifacts and ring effects.

The block artifacts occur when quantizing a low frequency DCT coefficient, and the ring effects occur due to the information loss of the original video in the quantizing process for a high frequency DCT coefficient.

Therefore, the number of bits which will be processed is decreased, so that a distortion occurs in the reconstructed original image.

However, since the computed values have a matrix form, it is impossible to implement a real time computation due to athe large amount of computation.

Therefore, it is hard to say whether it is well adaptiveadapted well to the system.

Namely, the low pass filter technique hasrequires less computation amount compared to the regularization recovering technique and has, but has a small capacity for adaptively processing the images, so that the information is lost at an edge portion.

The regularization recovering method has an excellent performance and, but requires a large amount of computation when computing regularization parameters.

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