Restoration of a Poisson distributed image using a principle of extreme physical information

Suppose that an object which reflects or emits light is captured by a sensor. The image data are distorted in various ways. The aim is to restore the object. For this purpose, a new restoration method is devised. It uses the Fisher-information based principle of extreme physical information (EPI). This solves a variational problem I − J = extremum, expressing a flow of information J → I from source to output in the restoration problem. Here, the source of information is the Poissonian image data, and J is modeled as its Hartley information level. Also, I is the Fisher information in the output restored object. The approach dates from the 1980s. It has been already shown that many fundamental physical laws may be derived using EPI. In this paper, the EPI approach is applied to the restoration problem, wherein it regards the unknown restoration as another fundamental law. It models the source information J as obeying Poisson statistics, and assumes additional image distortions that are due to additive Gaussian noise and quantization of the image data. It is found that the quantization level determines the degree of smoothness (or sharpness) of the restored signal. An optimal level of image quantization can be accomplished by adjusting its cross entropy. Finally, the restoration method by EPI is validated by numerical simulations of the image forming and restoring system.     

8 mm收发组件信号分析

主要研究8mm波段,雷达FMCW信号的时域及频域特性,通过对理论值与实测值的比较、分析,验证了8mm收发模块的可行性,并为下级信号处理作了准备。     

激光打靶数字延时信号完整性的研究

针对高速数字电路设计中遇到的信号完整性问题,本文给出了激光打靶装置中高速数字电路延时分配原理.根据传输线理论,提出端接迹线最大匹配长度值限定法,结合PCB设计,可避免端接失配反射.由电学理论,建模串扰的产生及消除串扰的端接方式.通过对噪声电流I和瞬态负载电流IL复合干扰分析,采取了相应的抑制方法.打靶实验表明,对保证延时信号的完整性是有效的.     

恢复蛋白Recoverin正则模式分析的理论研究

采用旋转平移块方法对Ca2+/豆蔻酰基开关进行了正则模式分析(NMA). 研究结果表明, 恢复蛋白(Recoverin)的T态的N-末端与C-末端易于发生刚体逆向旋转, 一旦结合Ca2+, 很容易发生构象变化, 形成具有双向构象转变特征的I态. I态是一个中间结构, 既可以发生构象回转到T态, 又可以继续相对旋转到R态, 使豆蔻酰基完全暴露, 从而行使其信号传导生物功能. 从低频振动模式分析可以看出, 恢复蛋白具有构象转变这一本质属性.     

Automata and logics over finitely varying functions

We extend some of the classical connections between automata and logic due to Büchi (1960) [5] and McNaughton and Papert (1971) [12] to languages of finitely varying functions or “signals”. In particular, we introduce a natural class of automata for generating finitely varying functions called ’s, and show that it coincides in terms of language definability with a natural monadic second-order logic interpreted over finitely varying functions Rabinovich (2002) [15]. We also identify a “counter-free” subclass of ’s which characterise the first-order definable languages of finitely varying functions. Our proofs mainly factor through the classical results for word languages. These results have applications in automata characterisations for continuously interpreted real-time logics like Metric Temporal Logic (MTL) Chevalier et al. (2006, 2007) [6] and [7].     

Intensification of the Emission Signals Using the Reflection Mirrors Mounted to the Sample Holder of a Fluorimeter

Effects of the reflection mirrors mounted to the sample holder of a fluorimeter have been investigated. Analytical expressions are given for the emission intensity measured as a function of the concentration or optical density of the sample, in case one or two reflection mirrors are attached beside the sample holder to intensify the emission signals. The emission intensity calculated as a function of the sample concentration agreed well with the experimental data. By mounting two reflection mirrors, the emission signal was intensified by a factor of near 3.5. However, the degree of intensification depended strongly on the sample concentration and the linearity between the sample concentration and the emission intensity deviated significantly with increasing the sample concentration.     

Speech enhancement using linearly constrained adaptive constant directivity beam-formers

This paper aims to extend previous work on constant directivity beam-formers (CDBs), for the case of multiple desired speech sources, by designing a linearly constrained adaptive CDB (LCA-CDB) which preserves the beam-pattern in multiple look directions. Also, the proposed LCA-CDB, adaptively, minimizes the transient noise power in the output of the beam-former, and furthermore, produces some controlled nulls (controlled in both amplitude and angle) on the beam-pattern. This strengthens the system in removing permanent directional noises and producing a frequency-invariant beam-pattern with multiple main-lobes and controlled nulls in arbitrary frequency bands. Through simulating the system and the acoustical situations, the authors have tried to demonstrate the capability of the proposed method in enhancement of broadband and telephony speech in the presence of various noise sources (transient noise, permanent noise and uncorrelated white Gaussian noise). The simulation results obtained in this study confirm the efficiency of the proposed method in suppression of environmental noises.     

基于连续光谱分析的在线水质检测信号处理研究

在线光谱水质检测仪器是现代水资源环境监测技术的重要发展方向之一,具有多参数监测和准确度高、重复性好的技术优势,然在线被测水样的光谱信号处理是其关键核心技术,为此,基于连续光谱分析,建立了在线被测水样光谱测量信号的数学模型,提出了基于双波长光强比值不变性的光谱测量信号系统误差处理方法,并结合小波多分辨率滤波噪声处理技术,系统研究了基于在线被测水质参数光谱特征的背景干扰处理方法。以上信号处理方法应用于自主研制的多参数光谱水质监测仪器,在线检测标准环境水样及实际环境水样中的化学需氧量、六价铬和阴离子表面活性剂等水质参数,并与国家标准分析方法展开了现场对比测试,仪器的关键参数重复性(相对标准偏差RSD≤10%)与准确度(实际水样比对试验相对误差A≤10%)均达到并优于国家环境保护技术标准要求,表明该信号处理方法能够有效消除在线水质检测光谱测量信号的系统误差及噪声与背景干扰,对于提升光谱水质监测仪器的技术性能具有重要的作用。     

太阳光谱辐射计的信号传递与性能表征模型研究

太阳光谱辐射计作为一种专用光谱辐射测量仪器,对于其宽谱段和大动态范围的测量特点,准确完整地表征分光性能是十分重要的。研究内容旨在为太阳光谱辐射计的研制与验证提供明确的理论依据和测试方法,给出清晰而准确的机理模型和指标模型对光谱仪器系统的设计和评估提供指导。因此,重点阐述了光谱仪器系统的信号传递模型到性能指标模型的推导和建立过程。线谱扩展函数这种串联卷积模型能够综合反映仪器的各个元件对系统的影响,而且很容易通过窄带线谱光源测试而得到,并且线谱扩展函数矩阵能够清晰完整地给出光谱仪器的分光性能细节特性。而在线谱扩展函数的基础上再进一步提取关键几何特征,通过简单的算法定义即可得到半高全宽(FWHM),带外抑制和带外辐射这三项示性函数指标,可以很好地对分光系统的性能进行定量表征,是十分有效的光谱仪器系统性能评估的指标模型。     

某型飞机驾驶杆线性位移差分变压器传感器信号调理校正

飞机驾驶杆LVDT(线性位移差分变压器)传感器信号测试校正在航空测控研究领域具有十分重要的意义,提出了一种针对某型飞机驾驶杆LVDT传感器信号精确调理校正方法;介绍了飞机驾驶杆LVDT传感器原理,分析了AD598 LVDT调理芯片的使用局限,利用最小二乘法设计了精确调理校正方法;基于VC++2010开发环境,利用高精度的模拟校正源产生模拟激励校正信号,设计了驾驶杆LVDT多通道软件自校正方法,它可以有效提高解调电路的线性度和对称性,克服了AD598常规调理电路的使用局限,从而实现驾驶杆LVDT信号精确检测;理论分析与数值试验验证了所提方法的正确性和有效性。