Electronic speckle pattern interferometry based on spatial information using only two sheets of speckle patterns

Abstract

Speckle interferometry is an important deformation measurement method for an object with a rough surface. In this paper, a novel fringe analysis method is proposed that uses a new optical system, which uses a plane wave as the reference beam of the speckle interferometer. When the optical system is employed in fringe analysis, the deformation information and the bias components of the speckle patterns are clearly separated in the frequency domain. Therefore, the deformation information can be readily extracted using a Fourier transform, which gives a pair of real and imaginary components concerning the information. The specklegram is calculated using such a pair of components, and the phase map is obtained from the specklegram. Experimental results confirmed that the resolution power of this measurement method is higher than 1/261 of the wavelength of the light source of the optical system.     

基于快速散斑结构光三维重建的在线测量系统

在流水生产线中实现工件表面三维信息的快速获取及尺寸的快速测量是当前辊压成形等制造业智能化升级过程中的迫切需求。基于散斑投影的三维重建方法仅需利用单幅物体散斑图像即可重建出物体表面的三维数据,在流水线工件快速测量中具有一定优势。本文对散斑三维重建中较为耗时的对应点搜索算法进行了优化,并在此基础上研制出适用于辊压成形制造生产线的工件快速三维测量系统。实验结果显示,该系统具有较快的三维数据重建速度,测量误差在0.035 mm范围内,能够满足辊压成形工件三维结构尺寸的快速在线测量需求。     

利用超声回波跟踪技术测量血流速度的实验研究

文章主要介绍了利用超声回波跟踪技术进行血流速度测量的原理和方法,通过对运动弦线速度的测量实验,比较了这种方法和传统的超声多谱勒技术在血流速度测量上的性能差异。     

基于散斑检测的微型计算光谱仪研究进展

光谱分析技术具有快速、准确和绿色检测的特点,在科学研究、信息、生物医疗、食药检测、农业、环境和安防等领域有广泛而且重要的应用.然而现有光谱技术与检测设备通常较为庞大复杂,难以适合现场快检、轻载荷平台等便携式应用场景.近年来,微型光谱检测技术和设备受到广泛关注并得到迅速发展,具有尺寸、重量、功耗等方面的显著优势,尤其是基...     

水下加肋双层圆柱壳体振动传递特性分析

研究水下双层圆柱壳体振动传递特性具有重要的工程意义,尤其对于水下结构噪声快速预报和外壳表面速度场实时重构.以此为出发点,通过双层加肋圆柱壳体模型水下振动试验研究了不同激励条件下内外壳体振动特性;然后建立了水下双层圆柱壳体有限元模型,计算分析了壳体在流固耦条件下的振动路径及特性,找出了不同激励方向、流体耦合方式和内外壳体连接方式等典型因素下内、外壳体间振动传递规律,为速度场重构和水下噪声预报提供了一定的理论指导.     

Laser monitoring of the flow velocity in lymphatic microvessels based on a spatiotemporal correlation of the dynamic speckle fields

A method and the corresponding experimental setup for the in vivo laser monitoring of temporal variations in the velocity and direction of flow in lymphatic microvessels are described. Experimental results on the laser monitoring of flow in the mesenteric microvessels of rat are presented. The method is based on an analysis of the statistical properties of the dynamic speckle fields and provides for a high spatial resolution. The results of determination of the lymph flow velocity by the proposed method agree well with analogous data of functional transmission microscopy.     

基于单基元几何交汇法的被动目标测距测速研究

从理论上分析和推导了单传感器测距测速的几何交汇模型,该模型结合二维栅格搜索策略对具有稳定线谱的匀速直线运动目标进行距离和速度的估计。为满足交汇模型的测频精度要求,介绍了对短样本信号进行测频的谱估计法、过零法和Hilbert方法。把多组对应一定特征频率、正横距离、目标速度和信噪比的目标通过信号代入交汇模型进行计算机仿真,相应得出一系列测量误差曲线,分析结果表明,对于一定参数的通过信号该模型可以较精确的估计出目标的正横距离及速度。     

基于数字散斑的大型机翼弹性形变测量技术

飞机机翼在飞行过程中受气动力影响会发生弹性形变,导致机翼外载荷大小与分布变化,危及飞行安全.该文针对民用飞机在飞行过程中机翼弹性形变测量的需求,分析大型飞机的结构负荷,采用多组摄像机组合标定、机载摄像机位姿修正、大倾角散斑图像解算等视觉测量技术,开展多摄像机组合的大翼展数字散斑形变测量方法研究,设计适用于C919飞机飞...     

Estimation of the Dead-Time Period and Parameters of a Semi-Synchronous Double-Stochastic Stream of Events

The problem of estimating the parameters of a semi-synchronous double-stochastic stream of events is considered in the form of a mathematical model of streams of elementary particles (photons, electrons, etc.) arriving at a recording apparatus. The results are presented of a statistical experiment implemented using a simulation model and showing quite good agreement with the estimates obtained.     

自由体积理论下液体声速、声速系数及非线性声参量B/A的研究

用液体自由体积理论研究了有机液体的声速、声速系数及非线性声参量与分子结构和分子势能的关系。结果表明分子间的作用力是影响声速、声速系数及非线性声参量的主要原因。同时非线性声参量Ｂ／Ａ也体现了液体分子结构方面的信息。本文有助于对自由体积理论下液体状态方程的进一步研究。为揭示声速及其相关特性与微观机制的关系并为其定量计算作了有益的探索。     

自由体积理论下液体声速、声速系数及非线性声参量B/A的研究

用液体自由体积理论研究了有机液体的声速，声速系数及非线性声参量与分子结构和分子势能的关系。结果表明分子间的作用力是影响声速，声速系数及非线性声参量的主要原因。同时非线性声参量Ｂ／Ａ也体现了液体分子结构方面的信息。     

Theoretical design of vascular imaging based on hall effect

The conceptual technique of vascular imaging and blood flow functional imaging based on Hall Effect is presented in this article. With this non‐invasive approach, both 3D anatomical imaging of the vasculature and functional imaging of blood flow in the deep structure of the human body can be obtained without radiation risk. The technique is based on the fact that the induced charges can be generated when the blood flows through the magnetic field. The induced electric field strength is measured by two groups of detector arrays, which captures not only the position of vasculature in each section, but also the velocity of blood flow and vessel size. The captured images can also be used for 3D reconstruction of the anatomical models. The designed system architecture including both hardware and software is described. © 2013 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 23, 85–96, 2013     

利用射频信号解卷积估计组织和血流运动速度

基于射频信号解卷积,提出了一种无需MTI（Moving Target Indicator）滤波重建血流及组织运动速度的方法。对射频回波的采样序列进行快速傅里叶变换,在频域对相邻两次射频回波的频谱作解卷积处理,通过分析解卷后的数值序列得到组织和血流各自的运动速度。仿真实验对两组典型的时延参数的超声回波信号进行了血流和组织速度的估算,并与给定值比较,证明了方法的有效。该方法有助提高超声血流成像系统对低速血流的测量精度。     

一种声速-位置联合估计的水声导航定位方法

长基线水声导航定位方法利用各信标到水下航行器的信号传播时间和等效声速来估计水下航行器的位置,但各信标到水下航行器的等效声速估计存在误差,导致定位误差较大,且随着导航距离的增加,定位误差呈增长趋势。针对这一问题,提出了一种基于粒子滤波的水声导航定位方法,将等效声速和水下航行器的位置作为估计状态参量,通过测量信标信号到水下航行器的传播时间,建立粒子滤波模型对其位置进行估计,准确地估计并跟踪等效声速变化,从而提高定位精度,减小估计误差。仿真结果表明,在水下航行器初始位置未知的情况下,与常规方法相比,文中所提方法的定位精度提高了4倍左右。     

基于数字散斑相关技术的老化沥青砂浆自愈合特性

沥青砂浆作为沥青混合料结构体系的分散相,其老化后的自愈合特性是影响沥青混合料路用性能的重要部分,结合沥青路面服务环境的实际情况,将老化程度及愈合时间作为条件,采用数字散斑技术进行沥青砂浆的损伤愈合实验,分析并观测其损伤愈合过程。结果表明,利用数字散斑相关技术可以很好地观测沥青砂浆损伤愈合过程;经过短期老化后的沥青砂浆在损伤愈合过程中预切口位移最大;长期老化后两种沥青砂浆的愈合值都有所提升,并且基质沥青砂浆比SBS沥青砂浆具有更好的愈合效果;沥青砂浆在愈合过程中分为二个阶段,第一阶段愈合速率较高,愈合值较大,第二阶段愈合率下降,愈合需要更长的时间。     

Reliability analysis of the dynamic system for the Chen model through sequential order statistics

Recently, the two-parameter Chen distribution has widely been used for reliability studies in various engineering fields. In this article, we have developed various statistical inferences on the composite dynamic system, assuming Chen distribution as a baseline model. In this dynamic system, failure of a component induces a higher load on the surviving components and thus increases component hazard rate through a power-trend process. The classical and Bayesian point estimates of the unknown parameters of the composite system are obtained by the method of maximum likelihood and Markov chain Monte Carlo techniques, respectively. In the Bayesian framework, we have used gamma priors to obtain Bayes estimates of unknown parameters under the squared error and generalized entropy loss functions. The interval estimates of the baseline reliability function are obtained by using the Fisher information matrix and Bayesian method. A parametric hypothesis test is presented to test whether the failed components change the hazard rate function. A compact simulation study is carried out to examine the behavior of the proposed estimation methods. Finally, one real data analysis is performed for illustrative purposes.     

钟形口流量管入口段速度型面研究

航空发动机试验中通常使用钟形口流量管对进气流量进行试验。在测量过程中,针对测点布置不准确造成测量结果不准确及测量成本增加的问题,开展了管内入口段测量截面上的速度分布情况研究。本文分析了钟形口流量管的测量原理以及湍流状态下管内气流的流动状态,研究了测量截面沿直径方向上速度的变化,建立了管内径向速度分布的数学模型,最终通过试验与仿真的方法对速度分布模型进行了分析与验证,为准确得到管内空气流量提供了一种基于速度分布模型的新方法,即通过试验测得流量管测量截面上少数点的数据信息得到管内速度分布模型,从而得到更准确的管内空气流量值。研究结果对进气流量的测量以及发动机性能的评定试验有重要意义。     

Hybrid method combining orthogonal projection Fourier transform profilometry and laser speckle imaging for 3D visualization of flow profile

This paper reports a straightforward technique for three-dimensional (3D) visualization of a flow profile by a hybrid algorithm combining Fourier transform orthogonal fringe projection and laser speckle imaging techniques. The use of orthogonal projection aims to suppress the zero order allowing surface reconstruction with high spatial resolution and accuracy while analyzing the intensity fluctuations of diffuse backscattered laser light providing 2D flow information. Once both are achieved, 3D flow visualization can be displayed. The method is experimentally validated first with a plastic tube filled with scattering liquid (milk) running at various controlled flow rates and then with the tube embedded under scattering layers (chicken breast) of varying thickness. The system includes a single, common camera, a commercial projector (profilometry channel), a laser light source (flow channel), and a computer station. In addition, orthogonal projection processing was combined with Hilbert transform, increasing the visualization and resolution of the measured flow profile.     

基于数字散斑相关法的聚合物改性沥青混合料抗裂性能

为分析冻融循环对苯乙烯-丁二烯-苯乙烯（SBS）和橡胶粉（CR）改性沥青混合料抗裂性能的影响,首先,分别对盐溶液冻融循环和水溶液冻融循环改性沥青混合料进行了半圆试件弯拉试验,同时采用数字散斑相关法（DSCT）对加载过程试件表面的散斑图像进行处理,提取试件表面随着载荷变化的位移场和应变场信息;然后,通过分析变形场信息确定沥青混合料的抗裂性能,并与断裂韧性试验结果进行对比。结果表明:水平应变较适合用于对沥青混合料的抗裂性能开展特性研究;由水平应变-时间曲线可知,冻融循环后SBS和CR改性沥青混合料的抗裂性能均有所劣化,且盐溶液冻融循环对沥青混合料抗裂性能的影响要大于水溶液冻融循环的;与SBS改性沥青混合料相比,CR改性沥青混合料的抗裂性能较好。所得结论表明DSCT的分析结果与断裂韧性试验的分析结果一致,采用DSCT评价沥青混合料的抗裂性能是可行的。      

Image speckle noise denoising by a multi-layer fusion enhancement method based on block matching and 3D filtering

In order to improve speckle noise denoising of block matching and 3D filtering (BM3D) method, an image frequency-domain multi-layer fusion enhancement method (MLFE-BM3D) based on nonsubsampled contourlet transform (NSCT) has been proposed. The method designs an NSCT hard threshold denoising enhancement to preprocess the image, then uses fusion enhancement in NSCT domain to fuse the preliminary estimation results of images before and after the NSCT hard threshold denoising, finally, BM3D denoising is carried out with the fused image to obtain the final denoising result. Experiments on natural images and medical ultrasound images show that MLFE-BM3D method can achieve better visual effects than BM3D method, the peak signal to noise ratio (PSNR) of the denoised image is increased by 0.5?dB. The MLFE-BM3D method can improve the denoising effect of speckle noise in the texture region, and still maintain a good denoising effect in the smooth region of the image.