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A novel psychovisual threshold on large DCT for image compression.

Abu NA, Ernawan F - ScientificWorldJournal (2015)

Bottom Line: The psychovisual threshold on the large image block provides significant improvement in the quality of output images.The experimental results on large quantization tables from psychovisual threshold produce largely free artifacts in the visual output image.Besides, the experimental results show that the concept of psychovisual threshold produces better quality image at the higher compression rate than JPEG image compression.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Information and Communication Technology, Universiti Teknikal Malaysia Melaka, 76100 Melaka, Malaysia.

ABSTRACT
A psychovisual experiment prescribes the quantization values in image compression. The quantization process is used as a threshold of the human visual system tolerance to reduce the amount of encoded transform coefficients. It is very challenging to generate an optimal quantization value based on the contribution of the transform coefficient at each frequency order. The psychovisual threshold represents the sensitivity of the human visual perception at each frequency order to the image reconstruction. An ideal contribution of the transform at each frequency order will be the primitive of the psychovisual threshold in image compression. This research study proposes a psychovisual threshold on the large discrete cosine transform (DCT) image block which will be used to automatically generate the much needed quantization tables. The proposed psychovisual threshold will be used to prescribe the quantization values at each frequency order. The psychovisual threshold on the large image block provides significant improvement in the quality of output images. The experimental results on large quantization tables from psychovisual threshold produce largely free artifacts in the visual output image. Besides, the experimental results show that the concept of psychovisual threshold produces better quality image at the higher compression rate than JPEG image compression.

No MeSH data available.


Zigzag order of 256 × 256 image block.
© Copyright Policy - open-access
Related In: Results  -  Collection


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fig8: Zigzag order of 256 × 256 image block.

Mentions: An average Huffman code is calculated from the quantized transform coefficients. After the transformation and quantization of 256 × 256 image block are over, the direct current (DC) coefficient is separated from the AC coefficients. The AC coefficients are listed as a traversing array in zigzag pattern as shown in Figure 8.


A novel psychovisual threshold on large DCT for image compression.

Abu NA, Ernawan F - ScientificWorldJournal (2015)

Zigzag order of 256 × 256 image block.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4385660&req=5

fig8: Zigzag order of 256 × 256 image block.
Mentions: An average Huffman code is calculated from the quantized transform coefficients. After the transformation and quantization of 256 × 256 image block are over, the direct current (DC) coefficient is separated from the AC coefficients. The AC coefficients are listed as a traversing array in zigzag pattern as shown in Figure 8.

Bottom Line: The psychovisual threshold on the large image block provides significant improvement in the quality of output images.The experimental results on large quantization tables from psychovisual threshold produce largely free artifacts in the visual output image.Besides, the experimental results show that the concept of psychovisual threshold produces better quality image at the higher compression rate than JPEG image compression.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Information and Communication Technology, Universiti Teknikal Malaysia Melaka, 76100 Melaka, Malaysia.

ABSTRACT
A psychovisual experiment prescribes the quantization values in image compression. The quantization process is used as a threshold of the human visual system tolerance to reduce the amount of encoded transform coefficients. It is very challenging to generate an optimal quantization value based on the contribution of the transform coefficient at each frequency order. The psychovisual threshold represents the sensitivity of the human visual perception at each frequency order to the image reconstruction. An ideal contribution of the transform at each frequency order will be the primitive of the psychovisual threshold in image compression. This research study proposes a psychovisual threshold on the large discrete cosine transform (DCT) image block which will be used to automatically generate the much needed quantization tables. The proposed psychovisual threshold will be used to prescribe the quantization values at each frequency order. The psychovisual threshold on the large image block provides significant improvement in the quality of output images. The experimental results on large quantization tables from psychovisual threshold produce largely free artifacts in the visual output image. Besides, the experimental results show that the concept of psychovisual threshold produces better quality image at the higher compression rate than JPEG image compression.

No MeSH data available.