Comparison and Evaluation of Noise on Reconstructed Image
香苗 谷口 · Institutional Repositories DataBase (IRDB) · 2011
[Abstract] There are block distortion and mosquito noise as an especial distortion on a reconstructed image through compression data of a color still image by DCT method. I quantify these distortions each basis of four type of DCT and computed block distortion and mosquito noise for each type occured around block boundary. In the results of a comparative for the amount of these distortions, block distortions of Type-I and III showed the least distortion, and mosquito noise of Type-IV has the least and it of Type-III was next one. The amount distortion as added in two distortion was also thesame results in the case of mosquito noise. By the way, WDCT method is an improvement method for degradation image with super high compression ratio of a defect of DCT method. I computed theoretically PSNR, evaluation indicator for objective image quality, for the amount distortion by DCT method and WDCT method. The best PSNR was WDCT method with k＝8 (transform length kN and inverse transform length N) which of an internal resolution conversion, and worst one was usual DCT method.