关键词: 掌纹图象, 定位点, 轮廓线, 形态学, 感兴趣区域

Abstract: This paper focuses on the region of interest (ROI) extraction of online palmprint images which involve transition and rotation. Firstly, a threshold is used to make the palmprint image become a BW image. Then the contour line of the BW image is smoothed by morphology algorithmic rule. We extract Freeman chain code from the BW image and translate it into a function of angle. The key points are extracted by comparing the angle changes of the contour line of every neighborhood point. Finally the palmprint images are aligned according to the key points, and thus the region of interest of the palmprint image can be extracted easily. This method provides a necessary preprocessing for further feature extraction and matching. The experimental results on two palmprint image databases demonstrate the effectiveness of the proposed method.

Key words: palmprint image, key point, contour line, morphology, region of interest (ROI)