初步利用美国生产的Pyrocam Ⅲ热像仪和SIFIR-50激光器构建了太赫兹(THz)面阵成像系统, 对20元人民币水印进行了2.52 THz激光成像实验, 探索了面阵成像机制和图像增强方法。针对5幅图像叠加后的太赫兹面阵图像, 研究了对比拉伸变换、直方图均衡化和中值滤波等图像增强方法的效果。实验结果表明, 利用此成像系统和后续的图像处理, 能够获得与成像物体较相似的图像; 对于比较暗的图像, 不能单靠对比拉伸变换。采用直方图均衡化方法效果较好, 在直方图均衡化后再运用中值滤波, 图像增强效果会更好。

THz array imaging system is constructed by utilizing the thermal imager of Pyrocam III made in USA and laser of SIFIR-50. Imaging experiments on 20 paper money with 2.52 THz laser are done in order to explore array imaging mechanism and method of imaging enhancement. The effects of the methods of contrast stretching transformation, histogram equalization, and median filter are studied according to the THz array image added by 5 images. The experimental results show that employing this imaging system and subsequent image processing, the images obtained are similar with the objects. For the low contrast images, the effects are not obvious only by contrast stretching transformation. Good effects are gained with the method of histogram equalization, and the effects of image enhancement are better when employing mean filtering after histogram equalization.