Optical system design of fingerprint and finger veinimages compound acquisition

Due to the biological multi-mode identification technology, an optical system for compound acquisition of fingerprint and finger vein multiple images was designed and described.The optic camera for collecting fingerprint and finger vein images contains respectively 3 and 12 spherical lenses, which works at 650 nm and 850 nm wavelength with a 640×480 CCD and a 640×512 uncooled infrared(IR)detector as the imaging devices, respectively.With the aid of Zemax software, the optical system was designed and optimized to cause a good imaging quality. Image quality evaluation results show that the modulation transfer function(MTF)value of the fingerprint imaging lens is above 0.6 at 67 lp/mm, while the finger vein imaging lens is above 0.8 at 30 lp/mm.The view field spots'root-mean-square (RMS) radii of the 2 lenses are both much smaller than the detectors'pixel size, which are close to the diffraction limit, and the distortions are both less than 0.5%.Experiments prove that images acquired by this optical system have the merits of fine image quality and high resolution.