An efficient psychovisual threshold technique in image compression
Nowadays, psychovisual model plays a critical role in an image compression system. The psychovisual threshold gives visual tolerance to the human visual system by reducing the amount of frequency image signals. The sensitivity of the human eye can be fully explored and exploited in the qualitativ...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English English |
| Published: |
2014
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| Subjects: | |
| Online Access: | http://eprints.utem.edu.my/id/eprint/14899/1/AN%20EFFICIENT%20PSYCHOVISUAL%20THRESHOLD%20TECHNIQUE%2024pages.pdf http://eprints.utem.edu.my/id/eprint/14899/2/An%20efficient%20psychovisual%20threshold%20technique%20in%20image%20compression.pdf http://eprints.utem.edu.my/id/eprint/14899/ https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=92062 |
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| Institution: | Universiti Teknikal Malaysia Melaka |
| Language: | English English |
| Summary: | Nowadays, psychovisual model plays a critical role in an image compression system. The
psychovisual threshold gives visual tolerance to the human visual system by reducing the
amount of frequency image signals. The sensitivity of the human eye can be fully explored
and exploited in the qualitative experiment by describing what has been seen or by image
quality judgment. However, the result of the psychovisual threshold through qualitative
experiment depends on the test condition of the human visual systems and through
repetitive viewing sessions. In a modern image compression, there is a need to provide
some flexibility to obtain quality levels of the image output based on user preferences. The
concept of psychovisual threshold is designed to determine quality levels of the image
output. The psychovisual threshold represents an optimal amount of frequency image
signals in image compression. This research proposes the psychovisual threshold through a
quantitative experiment that can automatically predict an optimal balance between image
quality and compression rate in image compression. The contribution of its frequency
image signals to the image reconstruction will be the primitive of psychovisual threshold in
image compression. It is very challenging to develop a psychovisual threshold from the
contribution of the frequency image signals for each frequency order. In this research, the
psychovisual threshold prescribes the quantization values and bit allocation for image
compression. The psychovisual threshold is the basic primitive prior to generating
quantization tables in image compression. The psychovisual threshold allows a developer
to design adaptively customized quantization values according to his or her target image
quality. The psychovisual threshold is also elementary and primitive for generating a set of
bit allocation for frequency image signals. A set of bit allocation based on psychovisual
threshold assigns the amount of bits for frequency image signals. A set of bit allocation
refers to the psychovisual threshold instead of the quantization process in image
compression. This research investigates the basic understanding of the psychovisual
threshold in image compression. The experimental results provide significant improvement
in the image compression. The psychovisual threshold which is presented as quantization
tables, customized quantization tables and as a set of bit allocation gives a significant
improvement on both of the quality of the image reconstruction and the average bit length
of Huffman code. This research shows that psychovisual threshold is practically the best
measure for optimal frequency image signals on image compression. |
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