Three-dimensional optical tomographic imaging of breast in a humansubject

We present for the first time a full three-dimensional (3-D) reconstruction of absorption images of breast from continuous-wave (cw) measurements performed on a premenopausal woman. Our 3-D optical images clearly reveal a large primary tumor as well as a small secondary tumor in a separate location of the breast. The multiple tumors identified by our 3-D optical imaging have been confirmed by the subsequent biopsy examination of the breast. Quantitative information of the optical images obtained is provided in terms of the location, size, and absorption coefficient of the tumors.     

W波段三维近场安检成像系统

本文介绍了一套基于频率步进体制的W波段三维近场安检成像系统以及相应的成像算法。W波段信号可以穿透普通衣物,对人员携带的藏匿物品进行成像。成像算法通过在频率波数域进行插值处理可以完全补偿近场的波前曲面。文中阐述了频率波数域的插值过程以及实验数据的预处理过程。成像系统通过发射宽带信号得到高分辨距离像,通过提高工作频率得到高分辨方位像,方位向分辨率优于5mm。成像实验结果表明该系统性能优于现有的Ka波段成像系统。     

网络考试系统中数据库的设计及架构

介绍了网络考试系统在高校教学中的必要性,对网上考试系统进行研究,其目的是为教学资源的共享提供一种途径,提高教师的工作效率,保证考试的公平性与公正性。而作为网络考试系统来说,如何构架数据库是整个网络考试系统的核心,文章通过对网络考试试题库的分析来搭建数据库设计,从而解决网络考试系统的核心模块。     

电阻抗成像压控电流源的参数匹配设计

电压控制电流源的性能对电阻抗成像的效果影响很大,分析了由3个ICL7650S运算放大器构成的电压控制电流源电路,通过设置电路中匹配电阻的数值,使该压控电流源满足电阻抗成像系统的设计要求。仿真结果表明,该电压电流源的频率和幅值可调,在频率为10 k Hz~1 MHz范围内输出波形失真小,在信号频率为50 k Hz时输出阻抗可高达1.3 MΩ,信号频率小于150 k Hz时输出阻抗不小于100 kΩ,满足电阻抗成像系统要求。     

网络安全检测与监控系统总体设计

网络的安全对社会、政治、经济、军事、科技教育以及人们的生活和工作方式产生了巨大的影响。目标主机的TCP连接状态进行监控的方法，如果在某一时刻，发现从同一地点或从不同地点所发动的针对目标主机同一服务端口的连接请求数目超过正常阈值，并且大部分TCP连接的状态均处于SYN—RCVD，则表明很有可能是攻击行为，这时可以采取措施通知防火墙修改访问控制策略，中断连接请求，拆除已经建立的连接，或向网络管理员提示报警，关闭这一网络服务。     

Robust linearized image reconstruction for multifrequency EIT of the breast

Electrical impedance tomography (EIT) is a developing imaging modality that is beginning to show promise for detecting and characterizing tumors in the breast. At Rensselaer Polytechnic Institute, we have developed a combined EIT-tomosynthesis system that allows for the coregistered and simultaneous analysis of the breast using EIT and X-ray imaging. A significant challenge in EIT is the design of computationally efficient image reconstruction algorithms which are robust to various forms of model mismatch. Specifically, we have implemented a scaling procedure that is robust to the presence of a thin highly-resistive layer of skin at the boundary of the breast and we have developed an algorithm to detect and exclude from the image reconstruction electrodes that are in poor contact with the breast. In our initial clinical studies, it has been difficult to ensure that all electrodes make adequate contact with the breast, and thus procedures for the use of data sets containing poorly contacting electrodes are particularly important. We also present a novel, efficient method to compute the Jacobian matrix for our linearized image reconstruction algorithm by reducing the computation of the sensitivity for each voxel to a quadratic form. Initial clinical results are presented, showing the potential of our algorithms to detect and localize breast tumors.      

基于K阶簇分析的乳腺组织拉曼光谱成像研究

采用共焦拉曼光谱仪,测量了正常乳腺组织和浸润性导管癌组织的阵列显微拉曼谱3 000多个,利用自编软件对谱数据进行K阶簇分析(K-means cluster analysis),得到各簇的平均谱以及各谱的簇类别。各簇平均谱与商售的甘油三酸脂、胶原和肌动蛋白等纯生化物质的拉曼谱具有很高的相关性,说明K阶簇分析能够区分细胞质、细胞间质及脂肪等不同组织形态的拉曼谱;依据各谱的簇类别构建阵列拉曼谱的簇分析成像能够显现乳腺上皮组织的生化成分分布及乳腺管结构,与乳腺组织形态模型成像结果相互印证。本文研究预示簇分析是研究乳腺组织拉曼谱及提取诊断信息的有效手段,优势在于不需要知道组织样品的生化信息。     

Three-dimensional integral imaging display system based on negative lens array

An integral imaging display system based on negative lens array in real mode is proposed in this letter. Compared with the conventional integral imaging system with positive lens array, the negative one has a huge advantage on viewing angle. The minimum viewing angle of the imaging display system based on negative lens array is the maximum viewing angle of the positive one with the same parameters. And the imaging display system based on negative lens array can enhance the viewing angle to 180° with special parameters. Other parameters, such as resolution and depth-of-field, are the same in both systems. Another advantage is that the proposed imaging display system based on negative lens array can fill the image area gap between 0 and 2f. The feasibility of our proposed method is experimentally proved. This work has been supported by the National Natural Science Foundation of China (No.11474169) and the Hebei Provincial Science Foundation for Youths (No.F2016402115). E-mail:XXJiao@hebeu.edu.cn      

乳腺癌检测的三维时域微波断层成像方法

应用泛函分析和变分法,改进拉格朗日(Lagrange)乘子算法为一种三维时域微波断层成像方法,用于检测早期乳腺癌。该方法首先以最小二乘准则构造目标函数,将反演问题表示为约束最小化问题;接着应用罚函数法转化为无约束最小化问题;然后基于变分计算导出闭式的拉格朗日函数关于相对介电常数和电导率的Fréchet导数;最后借助梯度算法和时域有限差分(FDTD)法迭代求解。为了对抗噪声污染和逆问题的病态特性,采用了一阶的吉洪诺夫(Tikhonov)正则化方法。利用FDTD和PRP共轭梯度(CG)法,对三维半球乳房模型进行了仿真计算,仿真结果显示了方法的可行性。     

智能测量热成像系统MRTD的应用方法分析

针对已提出的基于神经网络智能测量热成像系统最小可分辨温差（MRTD）的方法,简要阐述其实现方法、理论根据、神经网络算法模型以及测试结果分析.MRTD智能测量是建立在大量主观训练数据的基础上,影响主观MRTD测试的各因素也同样影响最终智能测量的准确性.综合考虑算法模型等因素,分析了影响智能MRTD测试精度的各因素以及尽量减小其影响应采取的措施.同时,讨论了智能MRTD测量的实际意义以及将其应用到实际测量中还需进一步研究与解决的问题.     

基于LXI技术的网络化卫星测试系统设计

LXI总线技术应用于卫星测试系统,可以很好地解决分布式测试、远程测试和异构测试系统融合等问题.首先介绍了LXI总线技术的特点以及相对其他总线的优势,然后提出新一代基于LXI总线技术的卫星测试系统体系结构,从通用、互换、兼容等方面考虑进行了整个卫星测试系统的方案设计.     

集成成像系统实现三维物体旋转不变分类识别

提出一种基于集成成像系统和综合判别函数(SDF)实现三维物体旋转不变分类识别的新方法。方法利用集成成像系统获取旋转三维物体的单元像阵列图像,应用图像中各个单元像记录的三维物体信息之间的高关联特性,结合SDF,实现了三维物体的旋转不变分类识别。与已有方法相比,本文方法减小了识别过程的数据量,降低运算复杂度,提高了识别效率,且不受物体旋转角度的限制。针对多类旋转三维物体,利用本文方法实现了旋转不变分类识别,验证了方法的有效性。     

航空发动机叶片图像光学采集系统的设计

文章提出了将叶片置于光切显微镜工作台上,通过CCD将被测量的图像传到计算机中的图像光学采集系统设计方案,实现了多参数同时测量,具有测量精度高、效率高、测量范围广和方法简便的优点.     

红外成像测量系统稳定跟踪设计

为实现对快速飞行目标的稳定跟踪,必须提高红外测量系统的实时信号处理速度和伺服系统闭环控制跟踪精度.因此,在新型红外成像测量系统设计中,提出了采用了DSP高速图像处理,双边缘跟踪等方法,提高系统成像跟踪处理器快速性和系统带宽等性能.提出伺服系统采用速度滞后和加速度滞后补偿,构成等效复合控制的方法,解决了红外跟踪器图像传输的滞后时延对系统跟踪精度的影响.实际应用表明,红外成像测量系统稳定跟踪能力大大提高.     

Electrical impedance spectroscopy of the breast: clinical imaging results in 26 subjects

Electrical impedance spectroscopy (EIS) is a potential, noninvasive technique to image women for breast cancer. Studies have shown characteristic frequency dispersions in the electrical conductivity and permittivity of malignant versus normal tissue. Using a multifrequency EIS system, we imaged the breasts of 26 women. All patients had mammograms ranked using the American College of Radiology (ACR) BIRADS system. Of the 51 individual breasts imaged, 38 were ACR 1 negative, six had ACR 4-5 suspicious lesions, and seven had ACR 2 benign findings such as fibroadenomas or calcifications. A radially translatable circular array of 16 Ag/AgCl electrodes was placed around the breast while the patient lay prone. We applied trigonometric voltage patterns at ten frequencies between 10 and 950 kHz. Anatomically coronal images were reconstructed from this data using nonlinear partial differential equation methods. Typically, ACR 1-rated breasts were interrogated in a single central plane whereas ACR 2-5-rated breasts were imaged in multiple planes covering the region of suspicion. In general, a characteristic homogeneous image emerged for mammographically normal cases while focal inhomogeneities were observed in images from women with malignancies. Using a specific visual criterion, EIS images identified 83% of the ACR 4-5 lesions while 67% were detected using a numerical criterion. Overall, multifrequency electrical impedance imaging appears promising for detecting breast malignancies, but improvements must be made before the method reaches its full potential.     

数字阵列模块自动测试系统的研究与设计

数字阵列模块是数字阵列雷达的核心组成部分,利用高集成技术将数字收发模块和模拟收发模块封装成一个组件。由于数字阵列模块数量多、通道数目多、测试指标多,对其进行自动测试变得尤为重要。针对数字阵列模块的自动测试给出了系统设计,包括硬件和软件设计。通过应用VC与Lab VIEW动态数据交换技术、VC++多线程技术、UDP数据传输及数据后处理技术,较好地解决了数字阵列模块测试数据量大、难处理的问题。通过对某型雷达数字阵列模块的测试,表明该测试系统达到了很高的测试精度。     

EPON ONU芯片的硬件验证与测试平台设计

介绍了SHU 2006 ONU芯片的硬件验证与测试平台系统,利用该验证平台实现了SHU 2006 ONU芯片的功能以及TBI高速接口的时序测试.在该验证平台上,100M以太网的FTP数据传输速率可以达到8Mb/s.     

Three-dimensional half-plane diffraction: Exact solution and testing of uniform theories

The exact solution of the diffraction problem for a plane electromagnetic wave at oblique incidence on a perfectly conducting half-plane was obtained more than 30 years ago. Recent advances in the high-frequency diffraction theory enable us to present the final solution in much simpler and suggestive forms. This solution is next used to test two uniform theories of edge diffraction. We find that uniform asymptotic theory (UAT) developed by Ahluwalia et al. recovers the exact solution, whereas uniform geometrical theory of diffraction (UTD) developed by Kouyoumjian and Pathak does not. The error of UTD is discussed.     

双波段共口径成像系统光机设计与分析

为了克服机载光电有效载荷(可见光摄像机和红外热像仪)各自独立、焦距过短的缺点,着重对可见光/红外共口径系统关键技术进行了研究。采用可见光、中波红外双波段共用主次镜的光学结构,可见光和红外焦距分别为1 500 mm和750 mm。选用合适的光学材料、合理的支撑方式,对系统反射镜支撑组件进行了静力学、动力学建模,优化了结构形式。采用光机热集成分析方法,指导、评价和优化光机系统设计过程,提高结构固有频率,增强系统热稳定性适应范围。系统结构设计基频大于200 Hz,在5 ℃均匀温变工况和重力作用下,反射镜面形PV值小于/10,RMS值小于/40,光学系统传递函数(MTF)达到0.38。结果表明,采用该方法设计的光机结构固有频率高,重力及热耦合变形、抗振性能等方面均能满足要求,系统具有良好的成像质量。