大尺度三维几何尺寸立体视觉测量系统实现

基于立体视觉的大尺度三维几何尺寸测量技术是对外形不规则的大型物体进行几何量测量的有效方法。与传统的视觉测量技术不同,大尺度视觉测量的精度随测量距离的增加而迅速下降,同时大尺度空间下照明条件难以控制,也使得测量变得不稳定。因此如何在大测量尺度的前提下提高测量精度成为这一领域的研究难点。从立体视觉测量系统的原理出发,分析了影响系统精度的各种因素,将相位一致性变换与极线约束条件引入结构光光条中心提取之中,显著提高了图像分析的精度。研制了测量系统的样机并给出了实验结果,现场测试表明该系统可以有效地保证大尺度条件下的测量精度。     

闪光辐射照相及光学高速摄影图象的增强处理

本文介绍图象增强处理技术在闪光辐射照相图象及光学高速摄影图象中的应用.针对闪光图象及高速摄影图象的特点,研究了一些有效的图象增强方法,取得了很好的应用效果. 文中给出了部分应用实例.     

Turbulence microscale variation due to interaction with shock wave

A speckle photographic technique is used for visualizing the planar distribution of the refractive deflection angles of light transmitted through a compressible turbulent flow. Double exposure speckle photography is applied for the statistical analysis of such flows. Quantitative visualization of the planar distribution of the refractive deflection angles of the light transmitted through the compressible turbulent flow is performed. Turbulent structures are visible in the patterns of the deflection angles isolines. The 2-D correlation functions of these deflection angles are constructed and analyzed. A mathematical procedure for solving Erbeck-Merzkirch integral transformation is described and the 3-D density correlation functions are evaluated using 2-D correlation functions of deflection angles of the light passed through the turbulence. Received 14 November 1999 / Accepted 3 June 2000     

数码摄影中的化学

数码摄影已成为人们日常生活的一部分。在阐明数码摄影原理的基础上,着重介绍了数码相片冲印过程中一些重要的化学反应,以凸显化学在数码摄影中的作用。     

基于感知的右视点质量可分级编码算法

为了减少立体视频传输如此庞大的数据量,根据人眼的立体掩蔽效应,提出了基于感知的右视点质量可分级编码算法．该算法将宏块分为3类：平坦块、纹理块和边缘块,通过不同的量化步长使得右视点图像块的质量可分级．实验证明根据左视点的图像质量,右视点在人眼感知范围内码率减少25％～37％．该算法能在人眼主观察觉范围内很好地提高码率,进一步消除人眼立体视觉冗余．     

Use of a joint transform correlator architecture for study of speckle displacements

The optical speckle–displacement correlation technique (OSDCT) is proposed for study of in-plane speckle displacements. The joint transform correlator architecture is used to evaluate the displacements of speckle subimages of strained surfaces. The procedure of the correlation response producing as a result of cross-correlation of strainless and strained surfaces in a conventional joint transform correlator (JTC) is considered. The convenient techniques for a joint power spectrum transformation are selected. The systematic and random errors of a mean speckle pattern displacement of a rigid body motion calculated by using the OSDCT and the digital speckle–displacement measurement technique are compared. The robustness of some JTC versions (a conventional JTC, a JTC with median thresholding, a JTC with subset median thresholding, and a fringe adjusted filter JTC) to input noise of speckle patterns and output noise of a correlation response is studied.     

制作具有预期位相调制度的卤化银乳胶位相型薄全息光栅的研究

提出了一种制作具有预期位相调制度的卤化银乳胶位型薄全息光栅的方法。它通过分析所拍摄的第一张全息光栅的数据来获得最佳曝光参量，从而使继后的拍摄，在同样的实验条件下能获得所预期的位相调制度。文中给出了这方法的理论分析和某些应用。     

The application of high speed photography and white light speckle to the study of dynamic fracture

A white light speckle technique is combined with high speed photography to study the dynamic fracture of a sample of PMMA. A series of single exposure speckle patterns are photographically recorded at the rate of 2 × 10⁵ frames s^-1 during fracture of the sample. The displacement field around the tip of the propagating crack may then be determined by superimposing pairs of individual frames to form a ‘double-exposure’ speckle pattern. It is shown that the method gives values for the stress intensity factor K which are consistent with those obtained from other techniques.     

自动跟踪式同步机在高速摄影中的应用

自动跟踪式同步机是一种新型的多功能计时、延时仪器。它可以μs精度测量和显示被测时间间隔,并根据测量值自动跟踪被测对象,以±0.2μs的精度输出多路延时讯号,解决各种高速摄影中的同步问题。它具有极强的抗干扰能力,可以在放电电压1mv,放电电流10kA,空间电磁场5kV/m的强电磁干扰的恶劣条件下正常工作。本文详细介绍了自动跟踪式同步机在脉冲X光摄影、可见光高速摄影、动光弹摄影中的应用及其结果。     

双曲柄式160摄影机在战略靶场中的应用

文章叙述了靶场经纬仪中使用摄影机的类型与特点;指出更新的双曲柄式160摄影机具有技术性能高,操作方便,可靠性好等特点。经受了多种工作考验,为多种试验提供了高精度测量数据,最后给出了几种摄影机应用情况对照表。