Title :
Compression of color images using mixed transform techniques
Author :
Singh, I. ; Agathoklis, P. ; Antoniou, A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Victoria Univ., BC, Canada
Abstract :
A new technique for lossy compression of color images is presented. This technique is based on both the discrete wavelet transform and the discrete cosine transform. The wavelet coefficients are calculated using the cascade algorithm and coded using vector quantization and arithmetic coding. The coarsest scale wavelet coefficients containing the low frequency information are transformed using block DCT followed by scalar quantization. The proposed technique was tested using 256×256 aerial images. Compression ratios exceeding 60:1 have been obtained at a peak signal-to-noise ratio of above 30 dB without any perceivable degradation in image quality. The results obtained indicate that the proposed technique performs better than the JPEG standard
Keywords :
arithmetic codes; discrete cosine transforms; image coding; image colour analysis; transform coding; vector quantisation; wavelet transforms; 256 pixel; 67840 pixel; JPEG standard; aerial images; arithmetic coding; block DCT; cascade algorithm; color image compression; compression ratios; discrete cosine transform; discrete wavelet transform; image quality; lossy compression; low frequency information; mixed transform techniques; peak signal-to-noise ratio; scalar quantization; vector quantization; wavelet coefficients; Arithmetic; Color; Discrete cosine transforms; Discrete transforms; Discrete wavelet transforms; Frequency; Image coding; Testing; Vector quantization; Wavelet coefficients;
Conference_Titel :
Communications, Computers and Signal Processing, 1997. 10 Years PACRIM 1987-1997 - Networking the Pacific Rim. 1997 IEEE Pacific Rim Conference on
Conference_Location :
Victoria, BC
Print_ISBN :
0-7803-3905-3
DOI :
10.1109/PACRIM.1997.619967