Wavelet-Based Image Compression System with Linear Distortion Control

In this paper, an optimized quantization of wavelet transform coefficients and low complex distortion control system for image compression is proposed. Distortion control is an important issue in maintaining the desired quality in the retrieved signal of compressed data. We construct a linear relationship between the distortion and quantization scale, which is crucial for efficient quality maintenance due to its simplicity and accuracy. This method can provide wavelet-based image data compression with a precise linear prediction model, resulting in high compression performance. A genetic algorithm (GA) is used to optimize the indices of distortion and compression ratio (CR). The optimization can induce linear relationships among multilevel quantization scales and enable the control of multi-level quantization scales with a single variable. Then a curve fitting technique is used to produce the quantization scales formula which is controlled by a single value. The experimental results showed that the proposed method can obtain better compression performance and distortion control exactly as predicted, with low complexity. Key-Words: distortion control, genetic algorithm, image coding