Narrow pulse formation using nonlinear LC ladder networks

Soliton propagation in a nonlinear lossy LC ladder network has been studied. We propose a quadratic polynomial expression to model the C-V characteristic of the nonlinear capacitor of the LC ladder network. This fits the experimental C-V data better over a wider range of the applied voltage, compared with the conventionally used formulae.

Using this C-V expression, the Korteweg-de Vries (KdV) equation with a loss term has been obtained. This nonlinear equation has been solved by employing a novel technique that is based on Fourier series analysis. We have investigated the effects of bias voltage on the soliton pulse width and peak voltage and found a good agreement between the theoretical and experimental results.     

数字图像处理技术用于等倾线条纹的处理

本文利用数字图像处理技术,对光弹性条纹进行处理,实现了等倾线与等差线的分离,提高了等倾线的测试精度。同时利用微机系统进行主应力迹线的绘制,提高了主应力迹线绘制的准确性.     

A Soft X-ray Streak Camera with Slit Length of 30 mm

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A new approach for realizing the optical morphological dilation of 1－D gray images

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Design Considerations of a Television Camera Detecting Oil Slicks on the Sea

This paper describes a television camera system that automatically captures exclusive images of an oil slick on the sea. The system includes two optical wavelength filters (WFs), two charge coupled devices (CCDs), and a differential image circuit that produces an absolute value of a difference signal between two output images from CCDs. The operating principle is based on the fact that, due to the multiple-beam interference in the oil slick, there is a marked difference of intensity between light reflected from the surface of the sea and that from the slick. The probabilities to sense slicks under various conditions were calculated using two types of WF, i.e., a space-invariant WF and a space-variant WF, and it was found that the latter was far superior to the former.     

三维机器视觉中图象匹配的几种摄象机几何模型和误差分析

三维视觉中的一个主要问题是从不同的角度来确定物体的几何位置,而物体的位置则可由两幅实体图象的视差来确定.本文重点讨论图象匹配中几种摄象机的几何模型和误差分析.     

脉冲式光电编码器信号的检测研究

介绍了用单片计算机对脉冲式光电编码器信号进行智能检测的方法。这方法不用专用辨向细分电路，只用一个计数器和一个二输入电平口完成计算机与编码器的连接。主要功能如速度判断、方向和变向判断、位移脉冲累加、细分、输出与通迅等依靠软件和单片机内部功能实现。并且通过单片机智能地克服了目前硬件辨向细分电路在变向、抖动和快速情况下不能保证四分之一周期分辨率的缺陷。     

温度对航天相机光学系统影响的研究

空间环境温度的变化对航天相机光学系统成像质量的影响很大。分析了几种不同的温度分布形式,即均匀温度变化、温度梯度变化、径向温度梯度变化、周向温度梯度变化、轴向温度梯度变化和主、次镜间轴向温差的变化对光学系统成像质量的影响,并给出了相应的分析方法。     

Digital holography particle image velocimetry for the measurement of 3Dt-3c flows

In this paper a digital in-line holographic recording and reconstruction system was set up and used in the particle image velocimetry for the 3Dt-3c (the three-component (3c), velocity vector field measurements in a three-dimensional (3D), space field with time history (t)) flow measurements that made up of the new full-flow field experimental technique—digital holographic particle image velocimetry (DHPIV). The traditional holographic film was replaced by a CCD chip that records instantaneously the interference fringes directly without the darkroom processing, and the virtual image slices in different positions were reconstructed by computation using Fresnel–Kirchhoff integral method from the digital holographic image. Also a complex field signal filter (analyzing image calculated by its intensity and phase from real and image parts in fast fourier transform (FFT)) was applied in image reconstruction to achieve the thin focus depth of image field that has a strong effect with the vertical velocity component resolution. Using the frame-straddle CCD device techniques, the 3c velocity vector was computed by 3D cross-correlation through space interrogation block matching through the reconstructed image slices with the digital complex field signal filter. Then the 3D-3c-velocity field (about 20 000 vectors), 3D-streamline and 3D-vorticiry fields, and the time evolution movies (30 field/s) for the 3Dt-3c flows were displayed by the experimental measurement using this DHPIV method and techniques.     

Time-Division Observation of Plastic Deformation Process Using Digital Speckle Pattern Interferometry

Time-division digital speckle pattern interferometry to observe temporal variation of in-plane deformation fields of a whole process of plastic deformation until fracture was proposed. Experiment of tensile test of an aluminum plate exhibited dynamic movements of successive fringe patterns which were very complicated. They suggest that plastic deformation propagates nonlinearly in the specimen by repetition of energy relaxation processes and concentration processes.Presented at 1996 International Workshop on Interferometry (IWI ‘96), August 27-29, Wako, Saitama, Japan.