单目标极小值优化法的多波长真温反演研究

在多波长温度测量系统中,光谱发射率假设为波长或温度模型来实现真温的求解。由于模型假设存在一定的不确定性,光谱发射率模型与实际光谱发射率的变化规律可能不符,会造成较大的真温反演误差。另外,光谱发射率与波长或温度之间的函数关系通用性较差,尤其是待测辐射体发生改变时,这种关系自然也就不复存在了。为了获得正确的真温,首次将优化思想引入到方法中,建立了单目标极小值优化法（Single Objective Minimization Optimization Method,SMO）完成真温反演。新方法无需建立光谱发射率和波长或温度之间的模型,降低了真温求解方法的复杂性和技术难度。与原有的光谱发射率与温度之间的模型（也称二次测量法,Second Measurement Method,SMM法）相比,在相同的初始条件下,新方法与二次测量法相比,反演速度提高了95%以上。     

一种测量固体火箭发动机羽焰温度的数据处理方法研究

针对连续测量固体火箭发动机羽焰温度的特点 ,提出了一种新的发射率假设模型 ,并在此基础上提出了一种新的多波长高温计的数据处理方法 ,即通过处理两个不同时刻多波长高温计的测量数据 ,由计算可同时获知两个时刻的真温及光谱发射率 .实验结果表明 ,其真温计算值与火箭发动机设计者提供的理论值之差在± 2 0K以内 ,说明该方法是解决固体火箭发动机羽焰温度测量的可行性方法     

基于模式搜索的光谱消光粒径分布反演算法的研究

发展快速有效的反演算法用于粒径分布的重建是颗粒测量领域重要的研究课题之一。在光谱消光法粒径测量中,提出将模式搜索算法用于独立模式下粒径分布的重建,同时引入Tikhonov平滑泛函构建算法的目标函数,为保证搜索过程的快速性和准确性,设计了关于初始点的优选策略。利用该算法测量国家标准颗粒体积平均直径的相对误差为3.14%,不超过国家标准物质局给出的±8%的范围,且粒径分布宽度合理,没有明显展宽和伪峰现象。与Phillips-Twomey方法和遗传算法的对比结果表明,在综合考虑反演精度和反演时间条件下,该算法具有明显优势,更适合于快速准确的现场测量,具有较好的应用前景。     

红外热像系统性能测试研究

分析了热像仪参数测试仪的基本结构,介绍了热像仪参数测试仪的发展现况,并对热像仪最小可分辨温差、系统调制传递函数和噪声等效温差等参数的测量方法进行了调研,给出了具体的测试方法。     

Calculation method for particle mean diameter and particle size distribution function under dependent model algorithm

In total light scattering particle sizing technique, the relationship among Sauter mean diameter D32, mean extinction efficiency Q, and particle size distribution function is studied in order to inverse the mean diameter and particle size distribution simply. We propose a method which utilizes the mean extinction efficiency ratio at only two selected wavelengths to solve D32 and then to inverse the particle size distri-bution associated with Q and D32. Numerical simulation results show that the particle size distribution is inversed accurately with this method, and the number of wavelengths used is reduced to the greatest extent in the measurement range. The calculation method has the advantages of simplicity and rapidness.     

反常衍射近似在测量圆柱形粒子粒径分布中的应用

在光全散射法颗粒粒径测量中,基于米氏(Mie)理论的计算方法只能求出均匀球形粒子的消光系数,而且计算复杂。通过反常衍射近似(ADA)代替米消光系数,可以简化粒径分布的反演过程。对使用反常衍射近似方法计算圆柱形粒子消光系数的可行性以及限制条件进行深入的研究,并在非独立模式算法下,采用遗传算法反演粒径分布。仿真结果表明,当粒子的相对折射率在一定范围内时,利用反常衍射近似反演圆柱形粒子的粒径分布是完全可行的,反演结果稳定、可靠。对消光值测量结果加入3％相对误差时,反演误差为5．7％。该方法具有简单、直观、计算速度快等优点,适合颗粒粒径的在线测量。     

中兴ZXMVC会议电视系统唯一通过联通入网测试

日前,中兴通讯ZXMVC会议电视系统成功通过信息产业部传输所依据联通入网技术规范主持的入网测试,中兴通讯是此次选型中唯一通过测试入围的民族通讯厂商。 经过对系统功能、接口、可靠性和兼容性等项目进行全面测试,专家组认为中兴ZXMVC会议电视系统不但符合各项相关标     

中国多媒体产业发展现状分析

一、国内多媒体产业发展的现状。“非典”给人类带来灾难的同时，也促进了国内视讯市场的繁荣。正如“911事件”不但促进了美国视讯市场的繁荣，更重要的是从此改变了美国国家的战略。同样，“非典”不但促进了国内视讯市场的繁荣，也将受消费习惯制约的、一直不能发展的电子商务、电子政务等模式真正推动起来了，从而使整个通讯产业发生了变革。     

An improved algorithm for cloud multiple scattering

Clouds' radiation characteristics are very important in clouds scene simulation, weather forecasting, pattern recognition, and other fields. Radiation of a cloud mainly comes from its multiple scattering. A new algorithm to calculate multiple scattering, called build-up factor algorithm, is proposed in this paper. In this algorithm, a modified gamma distribution is assumed to describe droplets distribution inside a cloud, then the radiation transport equation is calculated to get the solution of single scattering, and finally, a build-up factor is defined to estimate the multiple scattering contributions. This algorithm considers both single scattered radiance and multiple scattered radiance and needs shorter computing time. It can be used in real time simulations.     

Determining polymer film thickness during manufacturing with broadband transmission

A novel broadband transmission method to determine polymer film thickness during manufacturing is proposed, and a measurement system is developed based on this method. The relationship between broadband optical power and film thickness is deduced according to the Lambert-Beer law. The system is composed of a halogen light and an optical power meter. Results show that the measurement error of this method is approximately 1 μm, and the resolution of the system is below 0.4 μm for polymer films with less than 100-μm thickness.