A novel adaptive vein image contrast enhancement method based on fuzzy and retinex theory

A novel enhancement method for vein images is presented. This method combines the fuzzy and retinex theory and is suitable for enhancing the near-infrared vein images which have the bad conditions of low contrast, narrow dynamic range and asymmetrical intensity distribution. The optimal fuzzy transformation is used to enhance the global contrast. And for the purpose of compensating the shortage of the optimal fuzzy transformation in the enhancement of image detail information. Since in the process of map an image from spacial domain to fuzzy domain one-parameter optimization membership functions cannot have the optimal results, a two-parameter optimization of membership function is proposed, an adaptive approach is given to select the parameters of the two-parameter optimization of membership function. The experimental results show that this method can enhance the contrast between the vein patterns and its surrounding areas greatly.