Image restoration of skin scattering and optical blurring for finger vein recognition

Finger vein recognition has been adopted due to its high recognition rate and the invisibility of vein in visible light. However, because a finger vein pattern is not distinctive due to light scattering in the skin layer, the localization of a finger vein pattern region using an image processing algorithm is a difficult procedure. Also, optical blurring increases these difficulties. We propose a new finger vein image restoration method to deal with skin scattering and optical blurring. Our research is novel in three ways compared to previous studies. Firstly, the amount of optical blurring of a finger vein image is measured based on the average gradient of the orthogonal profile of a finger edge. Secondly, the accurate point spread function (PSF) of optical blurring is adaptively determined based on the orthogonal profile of a finger edge. Thirdly, using a constrained least square (CLS) filter and optimized parameters in terms of the lowest error of finger vein recognition, the restoration of a skin scattered and optically blurred finger vein pattern was performed. Experimental results show that the equal error rate (EER) of finger vein recognition with restoration was reduced by as much as 3.14% (5.05–1.91%) compared to the EER without restoration.

► Proposing a new finger-vein image restoration method to overcome skin scattering and optical blur. ► Measuring the amount of optical blur in a finger-vein image on the basis of the average gradient of the orthogonal finger-edge profile. ► Determining adaptively the accurate point spread function (PSF) for optical blur on the basis of this orthogonal finger-edge profile. ► Performing restoration of a skin-scattering and optically blurred finger-vein pattern using a constrained least squares (CLS) filter and parameters optimized for the lowest error in finger-vein recognition.