Optimized color space for image compression based on DCT and Bat algorithm

• Published in: Multimedia tools and applications Vol. 80; no. 6; pp. 9547 - 9567
• Main Authors: Touil, Djamel Eddine, Terki, Nadjiba
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2021; Springer Nature B.V
• Subjects: Algorithms; Color imagery; Computer Communication Networks; Computer Science; Cost function; Data Structures and Information Theory; Design optimization; Digital imaging; Image compression; Medical imaging; Multimedia Information Systems; Signal to noise ratio; Special Purpose and Application-Based Systems; Thresholds; Compression; PSNR; bpp; DCT; Color base; BA
• ISSN: 1380-7501; 1573-7721
• DOI: 10.1007/s11042-020-09754-0

This paper develops an efficient color image compression method based on the DCT and a new color base. Digital color images are commonly represented in RGB space. Generally, it is noted that a strong correlation exists between the three planes R, G, and B of a color image. The reduction of this correlation certainly offers an advantage in the compression of RGB images. In this context, there is an infinite number of possible spaces to represent the RGB image. The main contributions of this paper are summarized in two main points. First, we design an optimized color space B 1 B 2 B 3 using the Bat algorithm (BA) to pass from the RGB space to space more appropriate for each image. This space is produced by maximizing the energy of the image in the plane B 1 more than in B 2 and B 3 . Second, we produce optimized thresholds appropriate to each plane of the converted image. The Bat algorithm optimizes the cost function to compute thresholds to partially reduce the number of the less significant DCT coefficients that correspond to the lower quantity of energy. The reported results against those of recent methods prove that the proposed method presents high performances in terms of peak signal to noise ratio (PSNR) on the commonly used test color images as well as the test medical images in literature.