Abstract: In palm vein imaging system，in order to investigate the relation between light source wavelength and image quality，scattering and absorption characteristics of epidermis，dermis and fat in palm skin under near infrared light are analyzed and mathematical model is established.Then on this basis，it qualitative analyzes image quality under four single wavelengths including 760 nm，850 nm，890 nm and 960 nm.Finally，under the above mentioned four single wavelengths and six mixed wavelengths，it evaluates palm vein image quality by use of image contrast and two thousand and five hundred images are preprocessed and quantitative compared.Experimental results and theoretical analysis show that the image quality of palm vein is best under the light of 760 nm+960 nm wavelengths.

Key words: palm vein, Near Infrared, biological tissue, optical model, absorption characteristics, scattering characteristics, image contrast, image contrast

摘要： 在手掌静脉成像系统中，为对光源波长和成像质量之间的关系进行研究，对手掌皮肤中的表皮层、真皮层和脂肪层在近红外光下的吸收、散射光学特性建立数学模型，并对在760 nm、850 nm、890 nm和960 nm四种单波长近红外光下图像质量的影响因素进行分析。在上述四种单波长及其六种混合波长下，利用图像对比度作为图像质量评价标准，对2 500张掌脉图像进行了预处理和图像质量对比分析。实验结果和理论分析表明，在混合波长760 nm+960 nm下，最大程度保留了静脉信息。

关键词: 手掌静脉, 近红外光, 生物组织, 光学模型, 吸收特性, 散射特性, 图像对比度, 图像质量,