Intensity Constrained Flat Kernel Filter for Local Dark Feature Suppression. Application to Removal of Hair Artifacts in Dermatoscopic Images

摘要

The Intensity Constrained Flat Kernel Filtering (ICFK) scheme is a dual domain (spatial and intensity) nonlinear framework which has been shown to generate useful filters for image processing. This paper proposes a new filter developed within the ICFK framework. Although local in nature the filter is designed to suppress large scale spatial features within the image. As in every other filter derived within the scheme the suppressed features are defined by two parameters: size of the kernel and intensity range. The filter, a single-step procedure, is applied to removal of hair artifacts in skin lesion epiluminescence microscopy images, the task essential in assisting in automated segmentation of imaged area into lesion and surrounding skin. Results of the experiments on 400 dermatoscopic images of lesions with hair indicate suitability of the method as an aid in lesion segmentation by suppressing hair or vascular features near the lesion borders.