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Compression algorithm for low and high spatial frequency images.

Author(s)
Zeeshan Mustansar Chowdhry Karachi Institute of Information Technology, Karachi, Pakistan
Imdad Ali Ismaili Institute of Information Technology, University of Sindh, Jamshoro, Pakistan
Abdul Karim Baloch Department of Electronic, Telecommunication & Biomedical Engineering, Mehran University of Engineering & Technology, Jamshoro, Pakistan
Abstract
The intended research work is aimed at exploring image compression algorithm, techniques and data structures. The original image is taken through a series of steps each of which contributes to the overall compression of the image. Two types of algorithms are investigated for spatial low frequencies and for spatial high frequencies. Initially image pixels are grouped into blocks. DCT (Discrete Cosine Transform) is calculated for each element in the block, which represents isolated frequency components of colors and intensities. Quantization step is then applied to reduce bits for storage of DCT matrix. Run-length and Huffman encoding further reduce the image size. A modified form of LZW (LempelZiv-Welch) is built for GIF (Graphics Interchange Format), which provides a lossless or reversible compression method. This compression results in variable length codes, which are then reformatted into series of bytes for storage.
Publication Details
Page(s) 197-206
DOI DOI not available
Published Journal: Mehran University Research Journal of Engineering and Technology, Volume: 23, Issue: 2, Year: 2004

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