2.52THz面阵透射成像系统改进及分辨率分析

Improvement of 2.52 THz Array Transmission Imaging System and Resolution Analysis

太赫兹(THz)面阵成像具有成像速度快和像素多等特点,因此具有广阔的应用前景。成像系统的光路设计对成像质量具有很大影响。利用PyrocamⅢ热像仪作为面阵探测器,利用相干公司SIFIR-50连续太赫兹激光器作为成像光源,搭建太赫兹面阵实时成像系统,并通过多个离轴抛面镜和聚乙烯透镜对原有成像系统进行改进,以人民币水印、镂空金属板和分辨率板为目标进行实时面阵成像,获得了较为清晰的图像,通过与原有成像结果对比,验证了成像质量的提高,并通过分析成像结果对该成像系统的分辨率进行估计,该成像系统分辨率可以达到0.6 mm。

THz Array imaging has wide application foreground because of the high imaging speed and large detection area. The design of optical path has great effect on image quality. The THz real imaging system is constructed by use of the SIFIR-50 THz laser as imaging illuminant and Pyrocam Ⅲ thermal imager as array detector. The system has been improved using a series of off-axis parabolic reflectors and polyethylene lens. Imaging experiments on the object of water mark, hollowed-out metal board and resolution board have been made and clear images are obtained. By comparing with original imaging results, it is validated that the imaging quality is well improved. By analyzing the imaging results, resolution of the imaging system can be evaluated and reaches up to 0.6 mm.