Adaptive postfiltering of transform coefficients for the reduction of blocking artifacts

Chen, T.; Wu, Hong Ren; Qiu, Bin

doi:10.1109/76.920189

Cited by 146 publications

(112 citation statements)

References 23 publications

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“…This can be achieved by imposing the constraint such that if (6) Where σ represents the spread parameter of the input and controls the strength of the fuzzy filter. Note that the contribution of the input x[m,n] to the output is always highest compared to the contribution of other samples (7) For the same | …”

Section: Fuzzy Filtermentioning

confidence: 99%

Adaptive Fuzzy Filtering for Artifact Reduction in Compressed images and videos

Rao¹,

Addai²,

Ramakrishna³

et al. 2011

IJCSIT

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Section: Fuzzy Filtermentioning

confidence: 99%

Adaptive Fuzzy Filtering for Artifact Reduction in Compressed images and videos

Rao¹,

Addai²,

Ramakrishna³

et al. 2011

IJCSIT

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“…An adaptive finite impulse response (FIR) filter to effectively remove the blocky effect is also proposed. Chen et al [14] introduced a DCTdomain post filtering approach to reduce blocking artifacts, where the post-filter made use of the DCT coefficients of shifted blocks in order to obtain a close correlation between the DCT coefficients at the same frequency. The filtering adapts according to the local activity of each block to achieve simultaneous artifact reduction and detail preservation.…”

Section: Proposed Algorithm For Detection and Removal Of Corner Outliersmentioning

confidence: 99%

A post-processing algorithm for Detection & Removal of Corner Outlier

Gandam¹,

Sidhu²

2010

IJCA

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The reconstructed images from JPEG compression produce noticeable image degradation near the block boundaries, in case of highly compressed images, because each block is transformed and quantized independently. The blocking effects are classified into three types of noises: staircase noise, grid noise and corner outlier out of which major thrust is laid on corner outlier in this paper. A post-processing algorithm is proposed to reduce the blocking artifacts of JPEG decompressed images. The proposed postprocessing algorithm, which consists of three stages, reduces the blocking artifacts efficiently. A comparative study between the proposed algorithm and other post-processing algorithms based on various performance indices is made. General TermsJPEG Compression, Corner outlier et.al.

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“…We first obtain the unconstrained minimizer for by setting the partial derivative of the cost function with respect to to zero. Then, we clip the unconstrained minimizer to the quantization range which must fall in, and update by (13), shown at the bottom of the page, where is the clipping operator which clips the first argument to the range . Because the cost function is independent of the AC coefficients, the AC coefficients remain unchanged.…”

Section: A Optimization For Decoding the Luminance Background Blocksmentioning

confidence: 99%

“…The decoded image is then formed by computing the maximum a posteriori (MAP) estimate of the original image given the JPEG compressed image. Adaptive postfiltering techniques are suggested in [13]- [15] to reduce blocking and/or ringing artifacts in the decoded image. Filter kernels are chosen based on the amount of detail in the neighborhood of the targeted pixel to suppress JPEG artifacts without over-blurring details.…”

mentioning

confidence: 99%

A Document Image Model and Estimation Algorithm for Optimized JPEG Decompression

Wong

Bouman

Pollak

et al. 2009

IEEE Trans. on Image Process.

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Abstract-The JPEG standard is one of the most prevalent image compression schemes in use today. While JPEG was designed for use with natural images, it is also widely used for the encoding of raster documents. Unfortunately, JPEG's characteristic blocking and ringing artifacts can severely degrade the quality of text and graphics in complex documents. We propose a JPEG decompression algorithm which is designed to produce substantially higher quality images from the same standard JPEG encodings. The method works by incorporating a document image model into the decoding process which accounts for the wide variety of content in modern complex color documents. The method works by first segmenting the JPEG encoded document into regions corresponding to background, text, and picture content. The regions corresponding to text and background are then decoded using maximum a posteriori (MAP) estimation. Most importantly, the MAP reconstruction of the text regions uses a model which accounts for the spatial characteristics of text and graphics. Our experimental comparisons to the baseline JPEG decoding as well as to three other decoding schemes, demonstrate that our method substantially improves the quality of decoded images, both visually and as measured by PSNR.

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Adaptive postfiltering of transform coefficients for the reduction of blocking artifacts

Cited by 146 publications

References 23 publications

Adaptive Fuzzy Filtering for Artifact Reduction in Compressed images and videos

Adaptive Fuzzy Filtering for Artifact Reduction in Compressed images and videos

A post-processing algorithm for Detection & Removal of Corner Outlier

A Document Image Model and Estimation Algorithm for Optimized JPEG Decompression

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