Impulse noise removal by using one-dimensional switching median filter applied along space-filling curve reflecting structural context of image

Abstract

A switching median filter (SMF) is effective for impulse noise removal while still preserving edges in an input image. This filter firstly detects pixels corrupted by impulse noise and then filters only the noise-corrupted pixels. However the noise detection process does not always work perfectly. Particularly, pixels constituting thin lines in an input image tend to be incorrectly detected as noise-corrupted pixels, and such pixels are filtered despite the needlessness of the filtering. As the result of the filtering, the image might be over-smoothed and be deteriorated throughout the entire image. To cope with this problem, we propose a new impulse noise removal method based on a one-dimensional SMF and a space-filling curve which reflects structural contexts of an input image. The effectiveness of the proposed method is verified by some experiments.