在激光三维成像雷达中,双光楔扫描是一种常用的扫描方式,具有能耗小、精度高、抗震性好等优点,并可有效减小系统的体积。但其扫描轨迹复杂,扫描点存在较大的冗余。首先基于一级近似公式研究了扫描轨迹的规律,随后分析了扫描轨迹间距和扫描点间距的变化特征,最终确定了全视场覆盖时的双光楔扫描参数,并由轨迹分布特征给出了降低冗余的方案。结果表明,全视场覆盖时,反向旋转和同向旋转具有相同的最小冗余2π,除旋转方向外,其他扫描参数完全相同。有效扫描视场和分辨率一定时,特定转速对下,部分覆盖的反向旋转可减小1/4的冗余;半周期的同向旋转可减小1/2的冗余。冗余降低的同时提升了成像的帧频。

Herein, a new imaging-transformation method for acquiring a measurement matrix is proposed. A visible light camera is used to capture amplitude-modulated plate pattern information, then a coherent imaging algorithm is used to obtain the simulated light field, and finally the simulated light field is transformed into a ghost imaging measurement matrix. We validate the feasibility of this imaging-transformation method using an established tcrahcrtz ghost imaging system. Experimental results show that the measurement matrix obtained using the proposed method can enable tcrahcrtz ghost imaging to reach diffraction limit resolution. The resulting image quality is superior to that obtained using the classical scanning method. In addition, we experimentally study the influences of sampling frequency, pupil function, and matrix resolution on the final image quality.

A terahertz imaging system based on active ghost imaging method is proposed.The system can achieve high speed and high resolution imaging using one single-pixel detector, breaking through the resolution limit of terahertz devices.Reusable measurement matrix is obtained by the rotation of double random amplitude plates so that the imaging speed is greatly improved.The influence of imaging distance, size of random pattern, sampling number and the relativity of sampling matrix on imaging quality are numerically analyzed.The best parameters are used for experiment.And the motion strategy of double amplitude plates is optimized.Experimental results show that the imaging resolution is 4 mm when the wavelength of terahertz source is 3 mm, and imaging speed is determined by the motor of amplitude plates.The feasibility of terahertz active ghost imaging method is proved.