中文摘要：

文章介绍了工作在375GHz的太赫兹成像系统，成像系统由3个透镜、返波管源、倍频器、戈莱盒、金属线栅和示波器等部分构成。并用硬币做了太赫兹反射成像实验以验证成像系统效果。太赫兹信号照射到硬币上，逐点扫描硬币，检测经反射的太赫兹信号，提取出其信号幅度。实验结果表明成像效果良好，并采用非线性频谱外推算法对原始图像进行处理，提高了图像可视性。

英文摘要：

In the paper a THz imaging system is presented in detail by using three lenses as beam wave converter, a backward wave oscillator （BWO） and frequency multiplier as source, a Golay Cell box as detector, a polarizer as wave beam splitter, an oscilloscope as data acquisition device and image processing methods. The incident THz wave is reflected by coins and the amplitude of reflection wave is detected. The Chinese coins are scanned the plane perpendicular to the THz wave incident direction with the S＇ type step-step movement. The experiment of Chinese coins shows that THz reflection imaging photo is good. The photo quality can be enhanced with nonlinear extrapolation in the frequency space.