实时声学造影改善左室心内膜缘显示的实验研究

采用实时声学造影技术对健康杂种犬7只行造影检查,评价八氟丙烷声学造影剂改善犬左室心内膜缘显影的可行性和安全性.结果表明八氟丙烷声学造影剂可以明显改善心内膜缘显像,各剂量八氟丙烷声学造影剂均未对实验动物血流动力学及心电活动产生影响.     

实时三维超声心动图评价风湿性二尖瓣狭窄瓣口面积的初步研究

为探讨实时三维超声心动图定量评价风湿性二尖瓣狭窄瓣口面积的可行性及准确性。分别应用二维法（2D法）、多普勒压力减半时间法（PHT法）及实时三维容积法（RT3DE法）检测42例风湿性二尖瓣狭窄患者二尖瓣瓣口面积（MVA）。结果除1例患者因二尖瓣瓣叶严重粘连钙化,未获得清晰的二尖瓣口三维图像外。其余41例风湿性二尖瓣狭窄患者均获得满意的二尖瓣瓣口实时三维图像：另外．RT3DE法与2D法及PHT法测量所得MVA差异无显著性意义（P〉0．05）．且相关性好（r分别为0．945、0．809）。可见实时三维超声心动图评价风湿性二尖瓣狭窄瓣口面积具有可行性和准确性．为临床风湿性二尖瓣狭窄瓣口面积的评价提供了一种新的测量方法。     

Magnetic scan head for high-frequency recording

A stationary magnetic head scans the width of a record magnetically, enabling successive lines of video information to be recorded on a slowly moving tape. The head contains a large number of laminations. All except one of these are blocked from transducing action with the tape by currents through sweep windings. As the sweep currents are changed, every lamination becomes active in succession. For playback, such a head operates on a magnetic-modulator principle which is sensitive to flux rather than to its rate-of-change.     

机器人辅助无框架定位脑外科手术系统

研制了机器人辅助无框架定位脑外科手术系统,该系统可以在CT和MRI图像上实施病灶以及头颅的半自动分割,并将分割结果重构为三维模型,此模型可以进一步应用于虚拟手术规划及手术实施。它提供的三维组织模型清晰准确,手术路径精确稳定,从而提高了手术的效率和质量,降低了手术的费用。该系统在多例临床手术中获得了良好的效果。     

An error correction technique for scan conversion-based transientdigitizers

A statistical technique for the error correction of scan conversion-based transient digitizers is presented. The technique is based on the identification of the error model and on the assessment of the related correction feasibility. The identification of the error model is carried out for the charge distribution on each column of the target diode matrix of the scan digitizer through a suitable experimental procedure. The feasibility of the error correction is assessed on the basis of the statistical significance of the model identification by means of a decision-making procedure. A suitable index is utilized to verify the likelihood of carrying out a significant correction. Furthermore, for scan digitizers having a reference offset generator, a self-calibrating function based on the proposed technique is suggested. Finally, experimental results of the technique application to an actual scan conversion-based transient digitizer showing a significant error reduction are discussed     

扇形超声扫描仪数字扫描变换器的研制

本文介绍一种用于Ｂ型扇扫超声成像的数字扫描变换器。它采用一种针对有效像素点变换的技术，有效地降低了对电路速度的要求，从而提高了数字扫描变换器的性能，有利于高级图像处理技术的实现。     

A nanowire-based shift register for display scan drivers

The development of display scan drivers is an essential step in the effort to develop transparent and flexible display devices based on nanowire transistors. Here we report a transparent nanowire-based shift register that functions as the standard logic circuit of a display scan driver. To form the shift register circuits using only n-type nanowire transistors, a novel circuit structure was introduced to avoid the output voltage drop typical of purely n-type circuits. A circuit simulation based on the measured nanowire transistor characteristics was developed in the planning phase to verify the circuit operation of the shift register. The shift register successfully produced an output of 0-3 V without an output voltage drop while applying an input of 3 V peak to peak. In addition, the shift register was designed to have multiple channels with a randomly oriented nanowire placement method to enhance the operation yield.     

亚表面缺陷的实时成像检测

提出一种适合于金属亚表面缺陷的可视化无损检测方法——磁光/脉冲涡流成像方法。该方法以脉冲信号激励产生涡流,以激光对被检测物体的照射取代传统涡流检测的线圈探头,通过磁光传感元件将缺陷引起的磁场变化转换成相应的光强度的变化,由传统的显微镜、照明系统、偏振器和CCD图像传感器组成的光学系统将光强变化转换为“明”或“暗”图像,实现了对缺陷的实时成像检测。本文论述了磁光/脉冲涡流实时成像检测机理,给出了一种实验装置。通过对金属表面/亚表面缺陷实验,表明该检测方法快速、准确,可实现微/纳米级缺陷的成像检测。     

Real-time phase-front detector for heterodyne interferometers

We present a real-time differential phase-front detector sensitive to better than 3 mrad rms, which corresponds to a precision of approximately 500 pm. This detector performs a spatially resolving measurement of the phase front of a heterodyne interferometer, with heterodyne frequencies up to approximately 10 kHz. This instrument was developed as part of the research for the Laser Interferometer Space Antenna Technology Package interferometer and will assist in the manufacture of its flight model. Because of the advantages this instrument offers, it also has general applications in optical metrology.     

高温超导电缆实时监测系统及试验

介绍了用于10米长10．5kV／1．5kA三相交流高温超导电缆的实时监测系统。该系统采用NI分布式测量模块和数字电压表,通过计算机采集数据,能够在高温超导电缆的预冷和长时间通电运行时实时监测超导电缆中超导体的温度和循环冷却液氮的压力,能够监测超导电缆的通电电流和超导体上的电压,可以完成交流损耗试验。测量结果为研究高温超导电缆性能与相关参数变化的关系、研究高温超导电缆运行的最优条件奠定了一定的基础。     

Contrast echocardiography for pulmonary blood volume quantification

Pulmonary blood volume quantification is important both for diagnosis and for monitoring of the circulatory system. It requires employment of transpulmonary indicator dilution techniques, which are very invasive due to the need for double catheterization. This paper presents a new minimally invasive technique for blood volume quantification. An ultrasound contrast agent bolus is injected peripherally and detected by an ultrasound transducer in the central circulation. Several echocardiographic views permit simultaneous detection of contrast in different cardiac cavities and central vessels, and acoustic backscatter measurements produce multiple indicator dilution curves (IDCs). Contrast mean-transit-time differences are derived from the IDC analysis and multiplied times cardiac output for the assessment of blood volumes between different detection sites. For pulmonary blood volume estimates, the right ventricle and the left atrium IDCs are measured. The mean transit time of the IDC is estimated by specific modelling. The Local Density Random Walk and the First Passage Time models were tested for IDC interpolation and interpretation. The system was validated in vitro for a wide range of flows. The results show very accurate volume measurements. The volume estimate determination coefficient is greater than 0.999 for both model fits. A preliminary study in patients shows promising results.     

Optimal scan strategy for mega-pixel and kilo-gray-level OLED-on-silicon microdisplay

The digital pixel driving scheme makes the organic light-emitting diode (OLED) microdisplays more immune to the pixel luminance variations and simplifies the circuit architecture and design flow compared to the analog pixel driving scheme. Additionally, it is easily applied in full digital systems. However, the data bottleneck becomes a notable problem as the number of pixels and gray levels grow dramatically. This paper will discuss the digital driving ability to achieve kilogray-levels for megapixel displays. The optimal scan strategy is proposed for creating ultra high gray levels and increasing light efficiency and contrast ratio. Two correction schemes are discussed to improve the gray level linearity. A 1280×1024×3 OLED-on-silicon microdisplay, with 4096 gray levels, is designed based on the optimal scan strategy. The circuit driver is integrated in the silicon backplane chip in the 0.35 μm 3.3 V-6 V dual voltage one polysilicon layer, four metal layers (1P4M) complementary metal-oxide semiconductor (CMOS) process with custom top metal. The design aspects of the optimal scan controller are also discussed. The test results show the gray level linearity of the correction schemes for the optimal scan strategy is acceptable by the human eye.     

遗失目标的实时检测算法

针对视频安全监控问题,提出一种实时的遗失目标检测算法.首先,帧间差分用于获取像素级运动特性,并构造双重背景用于检测双重前景.而后,将像素级特性及双重前景综合以维持双重背景的更新.最后,通过累加证据图像来处理实际应用中的虚警和遮挡问题并证实遗失目标.在不同视频序列下的实验表明该算法能够有效地从嘈杂的场景中检测出遗失目标.此外,对于352x288的序列而言,该算法的运行速度达到约54帧/s,能够满足实时的监控任务需求.     

大型平行光管像质实时监测的可行性论证

针对目前大型平行光管成像质量监测的现状,本文提出了一种对平行光管进行实时监测的新方法,验证了这种监测方法的可行性.该方法根据光管自准检测原理,采用小平面镜对光管像质进行实时监测,计算了在一个焦深范围内小平面镜转角误差大小.实验结果证明在一个焦深范围内用精度0.02"的自准直仪,可将小平面镜转角误差控制在0.2"以内,对大型平行光管起到了进行实时监测的作用.大型平行光管在空间遥感设备中运用广泛,此检测光管像质的方法在工程上将起到积极的作用.     

光电经纬仪实时可视化仿真系统

经纬仪实时可视化仿真系统可用于操作手训练和经纬仪测试,构建了经纬仪仿真系统总体功能结构,主要完成经纬仪场景仿真和跟踪状态解算.论述了场景仿真中 CCD 虚拟相机成像模拟、目标轨迹仿真、目标脱靶量求取、背景云图模拟和实时图像效果添加等关键技术.建立了经纬仪跟踪控制系统 simulink 模型,通过 Real-time Workshop (RTW)生成了模型代码,并进行相应改写建立了跟踪状态解算模块.采用 VC++,Vega,OpenGL 和OpenGL 着色语言(GLSL)开发了仿真系统,实际应用表明,实时性良好,不需接入实际经纬仪系统,进一步降低了训练的成本,并能帮助实际系统进行测试、分析与设计.     

投影机镜头的MTF实时检测系统

目前还没有标准的方法来检测投影机镜头的MTF,为此我们提出了一种基于图像分析的投影机镜头MTF实时测试系统.本系统使用CCD作为成像接收器,采用基于图像分析的方法,通过分析单个像素成像同时获得投影镜头子午和弧矢两个方向上的调制传递函数(MTF).阐述了整个测试系统的构造及理论框架,着重分析了系统参数标定的重要性以及如何正确地进行系统参数标定;全面分析了影响测试结果的因素以及如何正确快速地修正噪声的影响.检测了质量合格与质量不合格的投影机镜头,并将结果同设计值的进行比较,实验结果表明了本系统及其处理方法的有效性.     

一种用于数码视频相机的实时自动聚焦算法

本文针对数码视频相机的噪声大,主体位置不确定性及实时性要求高等特点,详细讨论了传统自动对焦算法的缺陷并提出了一种新的自动对焦算法.该算法采用一种新的可有效抑制高频噪声的对焦量函数--高斯一阶导数(FDOG)来正确评价图像对焦趋势;支持最近主体优先的感兴趣区域自动选择,使得系统可以自动找到主体所在位置进行对焦;结合爬山法,二叉搜索和插值拟合进行对焦搜索,相比传统的两段爬山法,搜索效率提高了40%;通过对聚焦后的图像进行监视,支持视频模式下的动态自动对焦.该算法在一个数码视频相机平台上实现,实验结果验证了算法的优点,适用于高性能数码视频相机.