Colored Image Compression Using Gradient Adjustment Prediction Based Wavelet | Science Publications

Journal of Computer Science

Muna F.H. Al-Sammraie¹ 

关键词: Image compression;    wavelet transform;    space-frequency;    gradient adjacent predication;   

DOI  :  10.3844/jcssp.2011.304.313

学科分类：计算机科学（综合）

来源: Science Publications

【 摘 要 】

Problem statement: Uncompressed graphics, audio and video data require considerablestorage capacity and transmission bandwidth. Despite rapid progress in mass-storage density,processor speeds and digital communication system performance, demand for data storage capacityand data transmission bandwidth continues to outstrip the capabilities of available technologies. Therecent growth of data intensive digital audio, image and video (multimedia) based web applications,have not only sustained the need for more efficient ways to encode signals and images but have madecompression of such signals central to signal-storage and digital communication technology.Approach: The objective includes developing and applying an efficient Space-FrequencySegmentation (SFS) as an image partitioning scheme, then using an appropriate entropy-codingalgorithm that can be used with the developed segmentation to improve compression performance,particularly in the case of still image compression. The proposed compression system focuses on aninnovative scheme for adaptive wavelet coding technique combined with spatial encoding.Result: Experiments conducted using the proposed system produced encouraging results. The entropyspatialcoders used in the proposed system produced better results than those obtained by using thebasic arithmetic coder. It provides more appropriate rate-distortion optimization for the spacefrequencysegmentation than the basic arithmetic coder does. The proposed compression systemimplies some control coding parameters; the effects of these parameters were investigated to determinethe suitable range for each one of them. Conclusion: We conclude that a comparison between theenergy of two partitioning types (space and frequency) shows that the energy of frequency partitioningis greater than the space partitioning from the point of view of quality of compressed image. And alsothe selection of parameter value used in SFS part (Ratio and Threshold) should be chosen correctly,because its value has a great effect on the compressed image quality. And the selection of thequantization step size and the quantization factor (weight) should be done carefully, becauseexperimental results show that these two factors have a great effect on the compression ratio and PSNRfactor. Finally experimental results indicate that the use of GAP predictor produces better PSNR thanother predictors.

【 授权许可】

Unknown