Modified degree-based transition region extraction and thresholding

Existing degree-based method uses node degree as descriptor to extract image transition region, and achieves image thresholding via transitional pixels´ gray levels. The method is sensitive to salt & pepper noise. To solve this problem, a modified version is presented in this paper. The proposed method utilizes orientation information and characteristics of salt & pepper noise to distinguish transitional pixel and noise, improving accuracy of transition region extraction. In addition, we suggest a scheme for ruling out this type of noise in image thresholding result, further enhancing its noise immunity for salt & pepper noise. The modified version was compared with original degree-based method and famous local entropy-based one on a variety of images, and experimental results show its effectiveness and noise immunity for salt & pepper noise.