Image bandwidth compression by pre‐compensative interpolation
Kazuhisa Yanaka, Norio Saeki, Tadao Saito, Hiroshi Inose · Electronics and Communications in Japan (Part I Communications) · 1981
Abstract In the interpolative coding method, the pixels constituting the image are divided into “transmitted points” and “interpolated points,” and the former only are transmitted to the receiving end from the sending end. The latter are reconstructed by interpolation at the receiving end. Commonly, the original image values have been used for the transmitted point values as they are, or, the original image values have been properly lowpass filtered for the transmitted point values. However, judging from the entire image transmission system, the problem of how to determine the transmission point values at the sending end is closely related to the interpolation method at the receiving end. In this paper, we propose a pre‐compensative interpolation coding method such that given the interpolation method at the receiving end, the transmission point values at the sending end are determined so that the sum of the squared error between the transmitted points and interpolated points is minimized. We introduce two kinds of pre‐compensative interpolation coding methods for the case where the interpolation at the receiving end is linear, that is, a locally pre‐compensative interpolation coding method and a globally pre‐compensative interpolation coding method. According to a simulation using a standard image, the following effects have been recognized: the improvement of the SN ratio in comparison with existing simple linear interpolation which uses the original image values as the transmitted point values, and the decrease of the image quality degradation which seems to be caused by noise.