一种基于卷积核用于光刻模拟的计算稀疏空间点光强的方法

光学邻近校正(OPC)系统要求一种精确、快速的方法来预测掩模图形转移到硅圆片的成像结果.基于Gabor的"降解为主波"方法,一个部分相干成像系统可以用相干成像系统的叠加来近似,并用高斯过滤器来模拟光刻胶横向扩散和一些掩模工艺效应,由此提出了一种基于卷积核的精确、快速地用于光刻模拟的稀疏空间点光强计算方法.这种模型的简单性从本质上给计算和分析带来了好处.仿真结果说明这种方法是有效的.     

一种基于卷积核用于光刻模拟的计算稀疏空间点光强的方法

光学邻近校正 (OPC)系统要求一种精确、快速的方法来预测掩模图形转移到硅圆片的成像结果 .基于 Gabor的“降解为主波”方法 ,一个部分相干成像系统可以用相干成像系统的叠加来近似 ,并用高斯过滤器来模拟光刻胶横向扩散和一些掩模工艺效应 ,由此提出了一种基于卷积核的精确、快速地用于光刻模拟的稀疏空间点光强计算方法 .这种模型的简单性从本质上给计算和分析带来了好处 .仿真结果说明这种方法是有效的     

Quantitative evaluation of shape of image on photoresist of squareapertures

Simulation of images of two-dimensional structures in optical lithography is considered to have become quite important with the patterning of near-micrometer geometries in complex structures encountered in VLSI. Here, the results are presented of theoretical computations performed to calculate the aerial image of square apertures in a projection system using a partially coherent light source. The resist has been modeled by its sensitivity curve in order to compute the image profile on the resist after development. A figure of merit (FOM) has been proposed that quantifies the shape of the aerial as well as the resist image. Such an FOM has been proposed that can be used very effectively to optimize a lithographic process     

一种用于组合导航的SAR图像快速匹配算法

提出了基于合成孔径雷达(SAR)图像匹配技术的惯性导航系统(INS)/SAR组合导航方法。首先将计算机视觉领域的快速鲁棒性特征(SURF)算子用于对SAR图像的局部特征描述,然后对兴趣点建立快速索引,并用阈值为0.6的最近邻法则进行快速的初匹配,最后使用随机抽样一致(RSC)进一步去除错误的匹配点对。实验中,用2组真实的SAR数据对算法进行仿真并与尺度不变特征变换(SIFT)算子进行比较,结果显示,两者的鲁棒性相差很小,但在匹配时间上本文算法明显优于SIFT算子,本文算法更适用于组合导航的SAR图像匹配。     

一种快速的基于SIFT算法的无人机航拍序列图像自动拼接方法

无人驾驶飞机在短时间内具有相对稳定的航向、飞行速度、飞行高度等特点,这些特点决定了相同时间间隔的航拍序列图像的重合区域相对稳定,在此基础上,本文提出了航拍序列图像拼接方法的约束性条件,及一种快速的无人机航拍序列图像的自动拼接方法。该方法运用自回归模型,将历史相交区域中心点作为模型的输入数据,对当前用于拼接的重合区域进行预测,然后在预测区域内进行SIFT特征提取和特征提纯,并根据提纯后的特征进行快速的序列图像拼接。通过在无人驾驶飞机航拍序列图像上对该方法性能进行实验,结果显示本文的方法具有较好的拼接效果,在海量无人机航拍数据的情况下,能大大减少拼接时间。      

部分相干光通过多个硬边光阑ABCD光学系统传输的快速算法

部分相干光通过受光阑限制近轴ABCD光学系统传输是实际工作中一个十分有意义却是很困难的问题。虽然使用“Mathematia”编制的程序可对Collins公式作数值积分，但随着光阑数目的增加，计算变得非常繁琐和耗时。用有限个复高斯函数之和来逼近硬边光阑窗函数的方法，推导出了部分相干光通过多个硬边光阑ABCD光学系统传输的递推公式，提供了一种模拟部分相干光通过硬边光学系统传输的快速算法。计算示例表明，当离光阑不太近时，使用解析公式和直接对Collins公式作数值积分的结果符合甚好，并具有快速计算的主要优点，因此大为节约了机时。此外，由于将单光阑推广到多光阑的ABCD光学系统，并考虑了光束的部分空间相干性，因此所得结果更具一般性，且对多模部分相干激光是适用的。     

Magnetic resonance diffractive imaging

Magnetic resonance (MR) diffractive imaging is proposed as a new approach to MR angiography. The expression of the nuclear MR signal is similar to the equation for the Fresnel diffraction of a three-dimensional (3-D) object in light or sound waves. The proposed technique offers the possibility of fast angiographic imaging and the on-line reconstruction of 3-D volumetric images using the holographic technique. Static imaging experiments using an ultra-low-field MRI system are performed to verify the feasibility of the technique. It is shown that the images focused on an arbitrary plane can be reconstructed from data scanned in two dimensions, even though blurred image data is superimposed on the image. Moreover, the 3-D image can be observed in a coherent optical imaging system. This study demonstrates the possibility of the proposed method as a fast imaging technique for MR angiography.     

Alternatives for on-board digital multicarrier demodulation

In this paper alternatives for digital multicarrier demodulators (MCD) suitable for advanced digital satellite communications systems are presented. The MCD permits the direct on-board interfacing of FDMA and TDM communication links by digital signal processing techniques. Two main functions are implemented by a MCD: demultiplexing (DEMUX) and demodulation (DEMOD). We focus here only on a digital implementation of the MCD, looking at its advantages, flexibility, better performance and VLSI integrability. The DEMUX may be implemented in a number of ways: the analytic signal method, fast Fourier transform with polyphase network technique, or multistage methods. For all the implementation methods considered it is shown that a certain degree of integration of DEMUX and DEMOD functions is possible. To this end, in the proposed MCD schemes the receiver pulse-shaping filter has been integrated in the DEMUX structure, reducing the overall implementation complexity. It is shown that, for the per-channel structure based on the analytic signal method, a highly modular and flexible implementation can also be achieved. Coherent demodulation is used to reduce the signal-to-noise ratio required to achieve a specified bit error rate. The coherent demodulation is carried out by using the maximum likelihood (ML) estimation method. Two different approaches to receiver synchronization have been studied. For the first, the carrier phase and symbol timing estimates are independently derived by suitable techniques. The second approach makes use of the maximum a posteriori probability method to estimate both the carrier phase and symbol timing of the receivied signal. In particular, for this technique it is shown that, by a suitable choice of the architecture of the digital coherent receiver, the ML demodulator can be integrated in the joint carrier and clock recovery circuit, with no increase in the overall system complexity. The digital architecture of the proposed MCD can be adapted to different digital modulation techniques. However, here we consider only the application for QPSK signals, as this modulation scheme is the most promising for digital satellite communications. A theoretical analysis and computer simulation have been used to evaluate the performance degradation of the proposed MCD, including finite-arithmetic implementation effects.     

一种新的无人机航拍序列图像快速拼接方法

 无人驾驶飞机航拍序列图像的邻近帧间含有大量的相交区域,这些相交区域是进行基于特征的图像拼接的基础,但是也成为了降低拼接效率的冗余信息.因此,本文提出一种既稳定又具有较小时间开销的无人机航拍序列图像的自动拼接方法.利用图像拼接过程中查找到的匹配特征点,自适应提取出适于航拍序列图像快速拼接的关键帧;在分析了序列图像的拼接时的相交区域的运动模型的基础上,建立了无人机航拍序列图像配准过程中的特征搜索区域预测的卡尔曼滤波器,减少了特征搜索和配准的时间;然后给出了详细无人机航拍序列图像的快速拼接方法,实验结果显示,本文的方法具有较好的拼接效果和拼接效率.     

S-parameter-measurement-based high-speed signal transientcharacterization of VLSI interconnects on SiO2-Si substrate

A new S-parameter-based signal transient characterization method for very large scale integrated (VLSI) interconnects is presented. The technique can provide very accurate signal integrity verification of an integrated circuit (IC) interconnect line since its S-parameters are composed of all the frequency-variant transmission line characteristics over a broad frequency band. In order to demonstrate the technique, test patterns are designed and fabricated by using a 0.35 μm complementary metal-oxide-semiconductor (CMOS) process. The time-domain signal transient characteristics for the test patterns are then examined by using the S-parameters over a 50 MHz to 20 GHz frequency range. The signal delay and the waveform distortion presented in the interconnect lines based on the proposed method are compared with the existing interconnect models. Using the experimental characterizations of the test patterns, it is shown that the silicon substrate effect and frequency-variant transmission line characteristics of IC interconnects can be very crucial     

Contextual aerial image categorization using codebook

Effective categorization of the millions of aerial images from unmanned planes is a useful technique with several important applications. Previous methods on this task usually encountered such problems: (1) it is hard to represent the aerial images’ topologies efficiently, which are the key feature to distinguish the arial images rather than conventional appearance, and (2) the computational load is usually too high to build a realtime image categorization system. Addressing these problems, this paper proposes an efficient and effective aerial image categorization method based on a contextual topological codebook. The codebook of aerial images is learned with a multitask learning framework. The topology of each aerial image is represented with the region adjacency graph (RAG). Furthermore, a codebook containing topologies is learned by jointly modeling the contextual information, based on the extracted discriminative graphlets. These graphlets are integrated into a Bag-of-Words (BoW) representation for predicting aerial image categories. Contextual relation among local patches are taken into account in categorization to yield high categorization performance. Experimental results show that our approach is both effective and efficient.     

Mask design for optical microlithography--an inverse imaging problem.

In all imaging systems, the forward process introduces undesirable effects that cause the output signal to be a distorted version of the input. A typical example is of course the blur introduced by the aperture. When the input to such systems can be controlled, prewarping techniques can be employed which consist of systematically modifying the input such that it (at least approximately) cancels out (or compensates for) the process losses. In this paper, we focus on the optical proximity correction mask design problem for "optical microlithography," a process similar to photographic printing used for transferring binary circuit patterns onto silicon wafers. We consider the idealized case of an incoherent imaging system and solve an inverse problem which is an approximation of the real-world optical lithography problem. Our algorithm is based on pixel-based mask representation and uses a continuous function formulation. We also employ the regularization framework to control the tone and complexity of the synthesized masks. Finally, we discuss the extension of our framework to coherent and (the more practical) partially coherent imaging systems.     

On-board selection of relevant images: an application to linearfeature recognition

We propose an on-board selection scheme for aerial and space images, based on linear feature detection in a feature hyperspace. The detection task is performed by means of the Radon transform (RT) and the wavelet transform; a fast algorithm for the RT computation is described, and counteractions against the discretization errors are proposed. A new, wavelet-based algorithm is introduced, which performs a fine analysis of the waveforms of the RT peaks, yielding a possibly error-free detection in images corrupted by a high level of noise. A technique, based on the feature hyperspace, is proposed, able to significantly exploit all the available pieces of information on these peaks. Results of the tests on synthetic and real images are reported, which show that this method achieves satisfactory results, making the detection task highly reliable in the presence of both noise and clutter.     

航拍图像中玻璃绝缘子自爆缺陷的检测及定位

在分析输电线路无人机巡检系统航拍图像中绝缘子及其自爆缺陷特征的基础上,提出一种玻璃绝缘子自爆缺陷的检测及定位方法。该方法首先在色调、色饱和度、亮度(HSI)颜色空间分别对 H(Hue)和 S(Saturation)分量运用最大类间方差法(OTSU)分割图像,获取绝缘子前景连通域;之后,运用直方图方法对检测到的前景轮廓的倾角和面积分布进行统计,准确识别绝缘子轮廓;最后,设计了一种特征检测算法,检测并标记自爆绝缘子位置。实验证明该方法能从自然背景中准确检测并定位绝缘子自爆缺陷,具有较好的工程应用价值。     

Mask Design for Optical Microlithography—An Inverse Imaging Problem

In all imaging systems, the forward process introduces undesirable effects that cause the output signal to be a distorted version of the input. A typical example is of course the blur introduced by the aperture. When the input to such systems can be controlled, prewarping techniques can be employed which consist of systematically modifying the input such that it (at least approximately) cancels out (or compensates for) the process losses. In this paper, we focus on the optical proximity correction mask design problem for "optical microlithography," a process similar to photographic printing used for transferring binary circuit patterns onto silicon wafers. We consider the idealized case of an incoherent imaging system and solve an inverse problem which is an approximation of the real-world optical lithography problem. Our algorithm is based on pixel-based mask representation and uses a continuous function formulation. We also employ the regularization framework to control the tone and complexity of the synthesized masks. Finally, we discuss the extension of our framework to coherent and (the more practical) partially coherent imaging systems     

Metal defect localization of GaAs or Si based ICs by dynamic emission microscopy

Metal defect has become one of the major failure mechanisms of integrated circuit, whose localization might need skillful techniques in failure analysis, especially within function issues. Popular failure analysis method has been suggested for about two decades, such as PEM and laser stimulation microscopy. Most of the reported works are based on CMOS silicon substrate ICs, and mostly for frontside analysis by dynamic method. Since Gallium Arsenide (GaAs) based integrated circuit is developing very fast, the failures are also bringing challenges. Conventional dynamic method should be implemented in accordance with GaAs features.Emission characteristics of GaAs based pseudomorphic HEMT (PHEMT) and silicon based ICs were discussed in this paper corresponding to some possible consequences caused by metal defect. We proposed a dynamic emission microscopy method to solve the GaAs based high speed digital circuit open failure consist of DCFL inverters and performed a backside analysis on silicon based flipchip IC with metal bridge defect.     

多高斯模型特征空间覆盖学习的海洋航摄图像分割

本文提出了一种新的基于多高斯特征空间覆盖学习的航摄海洋图像分割方法.通过分析,发现在RGB三维色空间中,海水背景像素点的分布尽管在不同成像条件下具有不同的分布特性,但其具有的共同特性是具有集聚性,可以被一个或多个椭球所覆盖.因此,本文在色空间中基于贝叶斯最大后验概率和3δ准则对海水背景进行多高斯分布模型覆盖建模,自学习得到其高斯分布个数并建立相对应的多高斯分布模型.最后,根据上述学习结果,从航拍海洋的图像中分离出海水背景,实现航拍海洋图像中背景和目标的分割.实验证明,该方法具有良好的背景学习性能,能够准确有效地得到海水背景多高斯分布覆盖模型.基于该背景学习模型的海洋图像分割,具有较高的正确率和较低的误差,且算法花费的时间较少,具有较好的稳定性和实时性.     

Integrated ZVT auxiliary commutation circuit for input stage of double-conversion UPSs

This paper proposes an integrated zero voltage transition (ZVT) auxiliary commutation circuit applied to a universal input ac/dc system with a bidirectional converter for dc bus and battery bank interface. With the bidirectional converter it is possible to reduce the cost of the battery bank and virtually eliminate both low and high frequency current ripple in the batteries. An integrated ZVT auxiliary commutation circuit has been included to the system to achieve ZVT commutation at the main switches in all operation modes. In addition, this auxiliary commutation circuit controls the di/dt of the resonant process, allowing the utilization of slow diodes [intrinsic diodes of metal oxide semiconductor field effect transistors (MOSFETs)] in the bidirectional converter and, therefore, reducing the overall system cost. Integrated commutation circuit is based on a new concept in which the energy involved in one or more commutation processes is utilized to assist another commutation processes. Moreover, a control system has been developed and analyzed for the correct operation of the proposed system. Experimental results based on a 580-W prototype are presented to demonstrate the good performance of the proposed system.     

On-Chip Transient Detection Circuit for System-Level ESD Protection in CMOS Integrated Circuits to Meet Electromagnetic Compatibility Regulation

A new on-chip transient detection circuit for system-level electrostatic discharge (ESD) protection is proposed. The circuit performance to detect different positive and negative fast electrical transients has been investigated by the HSPICE simulator and verified in a silicon chip. The experimental results in a 0.13-m CMOS integrated circuit (IC) have confirmed that the proposed on-chip transient detection circuit can be used to detect fast electrical transients during the system-level ESD events. The proposed transient detection circuit can be further combined with the power-on reset circuit to improve the immunity of the CMOS IC products against system-level ESD stress.     

A Novel Discrete Dimming Ballast for Linear Fluorescent Lamps

A novel discrete dimming ballast for linear fluorescent lamps is proposed in this paper. A proposed dimming control circuit is combined with a ballast module for multiple lamps to realize control of three discrete lighting levels. Compared with conventional step dimming or on– off control methods, the proposed discrete dimming method has the following advantages: 1) digital signal is generated by the dimming control circuit to control the lamps' turn- on and -off, which makes the system more reliable and integrated; 2) the proposed discrete dimming system replaces relays, which are necessary in conventional lamp on–off control, and therefore decreases the system cost; 3) the proposed dimming ballast can be installed by keeping the original wiring system. This makes the upgrading of a lighting system more effective and efficient; 4) the dimming control circuit also provides a good isolation for operating the low-voltage wall switches by hand safely. Both theoretical, simulation, and experimental results are in good agreement.