Noise removal and deformation elimination
Olli P. Yli-Harja, Heikki J. Huttunen, Sami Laakkonen · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2001
In addition to suppressing noise, smoothers also cause an unwanted deformation of the image. In this paper we show how such deformation can be compensated. We consider the spectral behavior of noise removal by standard median filters. Observing the power spectrum, we notice that the deformation caused by median filter obeys the general form of the corresponding moving average filter, at least for i.i.d. input. We show that it is possible to cancel this deformation by using an approximation of the linear inverse filter, which can be easily implemented for images as well as 1D data.