A study on improving image quality of highly compressed moving pictures
Tomio Goto, Tatsuya Yamazaki, Masaru Sakurai · 2008
Recently, the opportunity to treat images has increased. Most of the images are large, so they are usually compressed with JPEG and MPEG, which is a major compression standard. JPEG and MPEG use DCT (Discrete Cosine Transform) for transform. The DCT causes more and more blocky noise as the compression rate is set higher and higher. The images taken in the past are usually strongly compressed. We propose a method of improving image quality using inverse wavelet transform. The proposed method transforms DCT coefficients into wavelet coefficients, decodes the coefficients by using inverse wavelet transform that selects the basis filters. The edge is protected by setting the threshold and controlling process, and improving image quality is aimed at.