中文摘要：

针对掌部静脉红外影像信噪比低、对比度不高、难以实现准确特征提取的情况,提出一种基于多尺度镜像曲波变换的掌部静脉影像增强新方法.基于多尺度曲波系数表达能力的剖析,该方法完全抑制了噪声高、特征信息少的高频子带系数,在去噪的同时非线性增强了细节特征丰富的中频子带系数,拉伸了反映影像整体对比度的低频子带系数.实验表明,该方法主观视觉评价和客观评价指数都显著提高,有效增强了低对比度掌部静脉红外影像特征,提高了影像信噪比和信息熵,其对静脉边缘特征的表达能力更优于双正交小波增强和直方图均衡化方法.

英文摘要：

A novel low contrast IR image enhancement method based on multi-scale mirror-extended curvelet transform was proposed to solve the problems of the palm vein IR images,such as low SNR（Signal/Noise） and low grayscale contrast as the results of incorrect feature extraction of palm vein.Based on the analysis of the strong relationship between multi-scale curvelet coefficients and different scales of detailed vein features,coefficients of high frequency subbands,where most of the noises and few features located,were set zero.The coefficients of middle frequency subbands,where most of the features concentrated,were nonlinearly enhanced during the denoising process.The coefficients of low frequency subbands who determined the global grayscale contrast were stretched.Experimental results show that the proposed method can efficiently enhance the features of low contrast palm vein IR images with increased evaluation indexes such as SNR and Entropy.By this method the features of vein edges are better preserved and more smoothly emphasized than enhancement methods of biorthogonal wavelet and histogram equalization.