Four-quadrant spatial phase-shifting Fourier transform digital holography for recording of cosine transform coefficients

A new one-step four-quadrant spatial phase-shifting Fourier transform digital holography is presented for recording of cosine transform coefficients, because cosine transform is a real-even symmetric Fourier transform. This approach implements four quadrant spatial phase shifting at a time using a special phase mask, which is located in the reference arm, and the phase distributions of its four-quadrants are 0, π/2, π, and 3π/2 respectively. The theoretical analysis and computer simulation results show that cosine transform coefficients of real-valued image can be calculated by capturing single four-quadrant spatial phase-shifting Fourier transform digital hologram.     

双光子和多光子共焦显微镜的成像理论

对双光子和多光子共焦扫描显微镜的成像理论作了系统的理论分析,导出了双光子和多光子共焦显微镜成像系统的三维点扩散函数和三维光学传递函数,研究结果表明：双光子共焦显微镜比单光子共焦显微镜具有更高的横向分辨率和纵向分辨率,而多光子共焦扫描显微镜又比双光子共焦扫描显微镜具有更高的空间分辨率. 关键词：     

利用时域递归辅助变量法计算极光激发参数

本文阐述了极光系统混型激发过程的时域表示及其谱分析方法，着重探讨使用时域递归辅助变量法计算极光参数。与传统排递归谱估计方法相比较，本文介绍的方法显出它的优越性。经改进后，该算法适用于估算时变参数，因而可以对极光过程的变化进行跟踪研究，利用方法对测量所得的极光亮度数据进行处理，结果确定了激发参数变化的存在。并说明了它们随时间变化的过程。     

Double-image encryption based on joint transform correlation and phase-shifting interferometry

An image encryption method combining the joint transform correlator (JTC) architecture with phase- shifting interferometry to realize double random-phase encoding is proposed.The encrypted field and the decrypting key are registered as holograms by phase-shifting interferometry.This method can encrypt two images simultaneously to improve the encryption efficiency of the methods based on JTC architecture,and eliminate the system alignment constraint of the methods based on Mach-Zehnder interferometer (MZI) architecture.Its feasibility and validity are verified by computer simulations.Moreover,image encryption and decryption can be achieved at high speed optically or digitally.The encrypted data are suitable for Internet transmission.     

电容层析成象的数值模拟

描述了两相流成象电容层析系统的有限元模型和利用反投影法进行数值模拟的方法，对典型的层流状模型重建出流体成分分布图象。     

电容层析成像原理及其在工业中的应用

介绍了电容层析成像的基本原理及共在工业方向的应用情况，展望它的发展前景。     

自适应算法在极光系统参数估算中的应用

讨论带参数的自适应时域方法计算极光系统的参数,以一个有理形式函数模型来代表系统函数,采用可以在线实时应用的递推自适应算法来确定该模型的参数。利用这种方法处理测量所得的极光亮度数据,现用互谱方法计算的氧原子「ＯＩ３２」跃迁时Ｏ（＾１Ｓ）态的平均有效寿命符合得很好。     

基于联合变换相关和相移干涉的图像加密

提出了一种在联合变换相关器结构中引入三步相移干涉和二元置乱技术的图像加密方法.用纯相位空间光调制器同时调制原始图像和两个随机相位掩模,利用三步相移技术分别将图像信息和主密钥加密为全息图,并用CCD在输出面上接收,再利用二元置乱技术置乱图像信息的全息图.在获得置乱密钥和附加密钥的情况下,可以通过一定的算法快速、清晰的重建原始图像.用计算机仿真验证了它的可行性和有效性.