POST-FILTERING OF LOSSY COMPRESSED NOISY IMAGES AND ITS EFFICIENCY PREDICTION

The object of the study is the process of lossy compression of noisy images and their post-filtering. The subject of the study is the approach to efficient two-stage processing (compression and post-filtering) for better portable graphics (BPG) coder and prediction of its efficiency. The goal of the study is to analyze performance characteristics of the considered two-stage approach and to propose an approach to their prediction. Methods used: numerical simulation, regression, statistical analysis. Results obtained: 1) the considered approach advantage is that it is able to provide improvement of quality of compressed noisy image under condition that an image is compressed with compression ratio smaller than that one corresponding to optimal operation point; 2) the approach efficiency depends on several factors including noise intensity, image complexity, and filter type and parameters; 3) the main characteristics of the two-step procedure can be quite accurately predicted in advance and this allows offering useful information for decision undertaking on what value of the coder parameter to apply; 4) this leads to either improving the compressed and processed image quality compared to its original version or, at least, to avoiding quality degradation. Conclusions: based on the results of the study, it is worth 1) predicting performance characteristics for the two-stage processing; 2) adapting the processing to image complexity and noise intensity.