Two-band lossless subband coding using nonseparable filter

✍ Scribed by Shinji Fukuma; Masahiro Iwahashi; Noriyoshi Kambayashi

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 823 KB
• Volume: 83
• Category: Article
• ISSN: 1042-0967
• DOI: 10.1002/(sici)1520-6440(200004)83:4<103::aid-ecjc11>3.0.co;2-e

✦ Synopsis

A lossless coding method that can restore digital images without any distortion is needed in areas that rely on high-quality images such as medical and broadcast applications. Lossless subband coding can obtain a high compression performance and enables progressive image transmission, and hence is known to be an effective lossless coding method. In the conventional two-band lossless subband coder, there are restrictions in the filter tap length, filter coefficients, and type of filter bank such as separable or nonseparable. Therefore, it is difficult to design the subband coder flexibly in response to special needs such as to increase the compression efficiency for a specific image, or to reduce the distortion in the progressive image transmission. In this paper, a two-band lossless subband coder is proposed that has several degrees of freedom in selection of the filter tap length, filter coefficients, and type of filter bank. These degrees of freedom are used for improvement of compression efficiency for a specific image. The filter coefficients are determined by the nonlinear programming. The proposed method is a general form containing the conventional method. For several test images, a compression efficiency higher than that in the conventional twoband lossless subband coder is confirmed.