激光全息干涉条纹的计算机数字图像处理

本文就激光全息干涉条纹的背景噪音的消除、图像对比度增强的技术与方法 ,进行了研究与探讨 ,从而实现对全息干涉条纹进行细化 ,获得清晰的易于计算机辨读的细化条纹     

基于Ronchi光栅检测非球面镜系统中的杂光现象分析

为指导某600 mm口径的双曲面反射镜的加工,设计了Ronchi光栅检测系统。针对系统检测过程中存在的杂光现象,分析产生该现象的原因,并提出相应的解决方案。结果表明,在光线两次经过光栅的光路结构中,分光棱镜的剩余反射率大于5%时,像面处暗条纹的照度增大27倍,条纹明暗对比度下降,难以分辨;随着光栅剩余反射增加,条纹中心产生亮斑现象,条纹无法分辨。条纹面正对分光镜的亮斑区域的背景照度增加40多倍,玻璃面正对分光镜的亮斑区域的背景照度增加80多倍。通过优化系统结构,对分光镜与光栅进行替换与表面处理,有效解决了杂光问题,提高了像面条纹对比度。     

消除散斑杨氏条纹图中衍射晕影响的新方法

提出了杨氏条纹观察屏处放置衍射晕负片消除衍射晕影响的新方法。用该方法对实际双曝光散斑底片进行了处理。结果表明．对解决由于衍射晕强度变化引起的条纹极值漂移和条纹对比度下降问题行之有效。     

一种适合低信噪比投影栅的时空二维相移算法

提出了一种适合低信噪比投影栅的时空二维相移算法。首先设计四步相移正弦光栅条纹图,由DLP投影仪投影到待测物体表面,再由CCD相机采集受物体形貌调制的变形条纹图;然后对其中一幅变形条纹图进行傅里叶变换以确定抽样间隔,再对4幅相移条纹图用相移法求得条纹背景和调制幅度后,对每幅变形条纹图做归一化处理;对每幅相移条纹图在空间域进行下采样抽样和灰度插值,构建相移莫尔条纹图,得到多帧时空域相移条纹图;对多帧时空域相移条纹图按时空二维相移法处理求得莫尔相位,再将莫尔相位与抽样点相位叠加求和得到变形条纹图对应的相位数据;最后,以面膜作为样品进行了实验测量,结果表明,经典四步相移法重构的物体形貌出现明显失真,而本文方法能较好恢复物体的三维形貌。     

基于单频四步相移条纹投影的不连续物体三维形貌测量

提出了基于单频四步相移条纹投影的不连续物体三维形貌测量方法。由计算机产生相移步长为π/2的4幅正弦条纹图像,利用液晶投影仪投影到被测物体表面,由CCD相机同步采集获得含有形貌信息的畸变条纹图并保存在计算机中,通过四步相移算法获得条纹相位信息。对于表面形貌不连续的物体,通过4幅畸变条纹图灰度算术和运算并进行二值化处理定位阴影或暗背景,利用二值图像修正解调的相位从而得到正确相位。实验结果验证了本方法的有效性。     

蜂窝夹层结构粘接质量电子散斑检测研究

蜂窝夹层结构粘接质量电子散斑无损检测,是利用电子散斑干涉技术,采用实时干涉法获得被检蜂窝夹层结构受热或压力载荷后的形变场条纹分布．受检的蜂窝夹层结构件蒙皮与夹芯之间的粘接缺陷,在适当的载荷力作用下,其表面位移场发生畸变,所对应的干涉条纹因其形状、间距和取向不同于周围粘接完好的干涉条纹的特征条纹,作为粘接缺陷的判据． 电子散斑干涉技术适用于检查碳环氧复合材料蒙皮厚度不大于 １．２ ｍｍ、铝蜂窝芯格边长不小于 ３ ｍｍ的蜂窝夹层结构粘接缺陷,可检测最小脱粘尺寸不大于直径 １５ ｍｍ．也适用于检查铝蒙皮厚度…     

计算机实时莫尔图象分析

莫尔形貌法由于能够获得关于物体表面形状的等高轮廊图,因此它的应用已引起人们的广泛注意。莫尔条纹的提取是莫尔技术中很重要的一项工作。实时测量由于受各种条件限制,所获莫尔图象往往含有背景条纹,     

基于模糊局部信息C均值的太赫兹图像目标检测

为了克服返波管太赫兹连续波成像系统所获取图像存在的对比度低、干涉条纹强等缺陷,较好地区分出目标和背景,避开不规则干涉条纹的干扰,采用基于模糊局部信息C均值的聚类算法用于目标检测,并针对太赫兹图像性质,对其中的隶属度函数进行了改进。结果表明,新的聚类分割算法适用于具有不规则条纹干扰下的太赫兹连续波图像,能较好地提取出图像中的目标,较经典图像聚类算法具有更好的目标检测精度。     

用于液晶盒表面面形检测的短相干载频干涉方法

液晶盒表面面形的质量会影响空间光调制器的性能。为了精确测量液晶盒表面面形,提出了短相干载频干涉方法。利用短相干扩展光源进行照明,产生的参考光和测试光之间形成定域干涉,通过控制参考面和液晶盒表面之间的倾角,引入合适的载频,得到待测载频干涉条纹;同时空液晶盒空气层上下表面干涉,形成背景干扰条纹,从而在CCD相机中采集到混叠有一组干扰条纹的单幅载频干涉图。通过空间傅里叶变换方法滤除背景和干扰条纹的频率信息,提取并恢复待测条纹包含的面形数据。实验检测了两块玻璃基片错位粘合制成的液晶盒表面面形,解算出波面峰谷值PV为8.286λ,波面均方根值RMS为1.782λ。使用该方法和ZYGO干涉仪进行的对比实验中PV值和RMS值分别相差0.023λ和0.004λ,两种测量方法得到的结果一致。该方法能够克服多表面干涉的问题,实现液晶盒表面面形的精确测量。     

全光纤VISAR系统中条纹常数的分析

全光纤VISAR系统具有大的测速范围，其测速的动态范围和条纹常数有关。从干涉光路的实现原理出发，推导出速度与条纹常数的关系式，并分析了FVISAR系统不同速度分档下的条纹常数确定。在保证1．5％精度及假设光源相干长度为1mm的前提下，给出了具体的速度分档情况。     

一种气(Ga)-固(Al掺杂氧化物)-固(Si)掺杂新工艺

针对制造高压晶闸管p型杂质扩散工艺的不足,进行了开管式受主双质掺杂技术的研究.通过大量试验和工艺论证,研制成一种气(Ga) -固(Al掺杂氧化物) -固(Si)掺杂新工艺.经应用证明,该掺杂技术能明显提高器件的电参数一致性、综合性能和成品率,为电力半导体器件研究和生产开辟了一条可行的受主双质掺杂新工艺     

Switched-voltage: an adaptation of switched-currents forvoltage-mode design

A novel sampled data signal processing technique is proposed, termed switched-voltage (SV). The technique is a dual approach to the recent switched-current technique. As with switched-current, the switched-voltage technique overcomes the incompatibility of the classical switched-capacitor technique to standard digital CMOS processes. The technique also relaxes the need for linear voltage-to-current and current-to-voltage converters in switched-currents for interfacing to the application environment     

A power efficient gain enhancing technique for current mirror operational transconductance amplifiers

In this paper, a power efficient voltage gain enhancing technique is described. This technique is suitable for the amplifiers which use current starving method for gain enhancement (explained in the text). The proposed technique makes use of the current which conventionally goes to ground, through a parallel path. In this paper, the new technique is demonstrated for current mirror type of operational transconductance amplifier (OTA). Simulation results show that gain improves by a factor ~2, while consuming the same power as conventional OTA. The added advantage of this technique is that it does not affect the voltage swing while increasing the gain. Compared to the conventional current starving technique, the proposed technique also improves the noise performance and settling speed of the amplifier. The results are compared with the conventional technique, in terms of gain, settling and noise performance. A comparison of FoM (MHz.pF/mA), with other amplifiers, is given at the end as well.     

清洗后硅片表面的电子结构

介绍了一种含表面活性剂和螯合剂的新型半导体清洗剂和清洗工艺。利用红外吸收谱、X射线光电子谱和原子力显微镜等 ,把它和标准 RCA清洗工艺的清洗效果做了比较。测试结果表明 ,经清洗过的硅片表面主要是由硅、氧和碳三种元素组成 ,它们分别以 Si-O键、C-O键和 Si-C键的形式存在。两种清洗技术都在硅片表面产生氧化硅层 ,在硅片表面都存在有机碳污染 ,但新型半导体清洗工艺产生的有机碳污染少于标准 RCA清洗。在对硅片表面的粗糙化影响方面 ,新型半导体清洗技术清洗明显优于标准 RCA清洗技术     

An Iterative Algorithm for Hardware-Software Partitioning, Hardware Design Space Exploration and Scheduling

The paper proposes a novel heuristic technique for integrated hardware-software partitioning, hardware design space exploration and scheduling. The technique maps an application specified as a task graph on a heterogeneous architecture with an objective to minimize the latency of the task graph subject to the area constraint on the hardware coprocessor. The technique uses an iterative approach where the partitioner decides the processor mapping and HW design points of some tasks. The scheduler then simultaneously decides the processor mapping, HW design point and schedule time of the remaining tasks. There exists a tight coupling between the two design stages allowing them to produce superior quality designs in fewer iterations. The technique accounts for the time overheads due to inter-processor /intra-processor communication and shared memory access conflicts. It can therefore be used for both communication intensive and computation intensive applications. The technique also considers dynamic reconfiguration capability of the hardware coprocessor. The technique performs tradeoff analysis and maps hardware tasks to mutually exclusive temporal segments if this results in lower latency. The effectiveness of the technique is demonstrated by a case study of the JPEG image compression algorithm, comparison with an optimal ILP based approach and experimentation with synthetic graphs.     

HFC接入网中的S-CDMA技术的研究

研究了基于电缆调制解调器(Cable Modem)技术的HFC接入网中的传输信道多址接入技术,分析了同步码分多址(S-CDMA)技术与其它多址接入技术相比所具有的特点和优势,设计了采用S-CDMA技术的HFC传输系统方案;并对此系统进行了性能分析.分析结果表明,S-CDMA技术是一种能有效实用于HFC系统的多址接入技术.     

VGT turbocharger controlled by an adaptive technique

This paper provides an adaptive technique for the control of the variable geometry turbine in a turbocharged compression ignition engine. The adaptive control is based on a one-step-ahead (OSA) technique and a least-square parameter estimator algorithm. In order to test the performance of the proposed control technique, a numerical model of the engine has been developed, which employs a thermodynamic (zero-dimensional) approach. The paper will show that the OSA technique is able to improve dramatically the control performance with respect to that provided by a commonly applied proportional integral derivative control technique.     

一种对抗组网雷达的新型组网干扰技术

针对组网雷达技术的不断发展,提出了一种新式的针对组网雷达的干扰技术,详细介绍了这种新干扰技术的干扰原理,并对这种新干扰技术的布站模式和RCS的计算进行了阐述,最后从有效干扰功率密度的角度分析了该方法的干扰效果。通过理论分析和计算证明该技术具有很多优势和发展潜力。     

Optimal scheduling techniques for cluster tools with process-module and transport-module residency constraints

This paper discusses two scheduling techniques for dual-arm cluster tools that address both process-module and transport-module residency constraints and throughput requirements. The first technique is the extension of our previous work that only addressed process-module residency constraints. For cases with long process times, this technique can take a long time to find the solution and is not practical. Hence, we use this algorithm mainly as a benchmark for comparison. The second technique that uses a linear programming technique with use of several heuristics can find the optimal solution very efficiently. Analytical and experimental analysis of this technique shows the correctness, completeness and efficiency of this technique.     

BUCK变换器的一种多环控制研究

文中研究了一种具有快速动态响应的多环控制方法,介绍了多环控制方法的工作原理,并建立了器件模型,利用Matlab的Power System Blockset对该模型的特性进行了时域仿真,并将仿真结果与传统的电压型。电流型控制方法进行比较,对分析结果进行了验证。