标准光伏电池在拉萨自然阳光下的一级标定

为解决光伏电池和光伏组件在测量中的量值溯源问题,在拉萨地区采用室外直接辐照度标定方法建立了标准光伏电池一级标定试验平台,能够同时测量入射光直接辐照度、大气光谱辐照度分布、电池短路电流及温度,并提出了一级标定试验所需的实验条件及实验方法。实验表明:光伏电池一级标定试验平台性能准确可靠,可获得较为理想的标定不确定度结果。     

基于MATLAB的光纤光谱仪校准的测试方法

采用光谱辐照度标准灯进行量值传递和MATLAB数据处理技术等来实现对光纤光谱仪的计量。简述了这种计量方法的工作原理以及数据处理过程。从理论分析和初步的实验结果证明了这一方法的有效性和可行性。     

氙灯紫外区光谱特征的研究

在不同的参数和工作条件下,测量了氙灯(150W)的紫外绝对光谱辐照度(200～380nm)。对其在此波段呈现的光谱特性进行了分析。得出计算氙灯光谱辐照度的经验公式。分析结果表明,氙灯具有成为高强度紫外光谱辐照度标准传递光源的良好光谱特性。     

光伏标准电池室外一级标定的不确定度分析

利用拉萨地区较好的阳光辐射条件,采用室外直接辐照度标定方法建立了标准光伏电池一级标定试验平台,提出了一级标定试验的实验条件及方法。对一级标定试验入射光辐照度、光谱失配修正、电池短路电流及温度等参数进行了不确定度分析及评定,标定结果具有较高的参考价值。室外一级标定采用绝对辐射计溯源至世界辐射基准,测量结果准确可靠,且具有较好的复现性。     

一种基于多传感器信息融合的火灾探测系统

根据火灾的特征与燃烧产物,设计了一种基于多传感器信息融合的火灾探测系统.该系统以DSP TMS320LF2407A为处理器,包括一氧化碳传感器模块、温度传感器模块和紫外火焰传感器模块.紫外火焰传感器可以很好地区分闪燃火和阴燃火,一氧化碳传感器和温度传感器能够对闪燃火和阴燃火产生不同的反应,因此系统采用两种不同的算法来探测闪燃火和阴燃火.该火灾探测系统在燃烧室中通过了实验验证.实验表明,该火灾探测系统比通用的感烟型探测器具有更快的探测速度和准确度,且不会在常见干扰源的干扰下产生误报警.     

发散光照射方法标定空间紫外遥感仪器光谱辐照度响应度

以辐射度学为理论基础,推导出了发散光和平行光两种照射方法标定的空间紫外遥感仪器光谱辐照度响应度的结果表达式,分析了影响两种照射方法定标结果的因素。通过相关的测试实验,数值估算了采用发散光照射方法为仪器进行辐照度定标时所引入的定标方法误差。计算结果表明,在假设平行光辐照度值均匀及发散光源为朗伯光源的情况下,采用发散光照射方法定标时所引入的定标方法误差小于1．2％。数值估算结果对于采用发散光照射方法为空间紫外遥感仪器进行光谱辐照度定标具有一定的指导意义。     

标准太阳电池标定值计量方法研究

基于差分光谱响应度法搭建了标准太阳电池标定值校准装置,分析了标准太阳电池绝对光谱响应度随电池温度和偏置光辐照度的变化关系,通过数值拟合得到太阳电池短路电流与偏置电流的关系,实现太阳电池标定值测量不确定度1.2%(k=2)。搭建了标准太阳电池标定值户外计量装置,实现测量不确定度2.38%(k=2)。差分光谱响应度法与户外总辐射法测量结果比对的比率值为0.95,表明2种方法测量结果在不确定范围内量值等效。     

上海市科学技术进步一等奖——定点辐射系统(金属凝固点黑体系列)介绍

在国际温标中,温度固定点的精确测量是其最基本的技术要素,在精确测量固定点热力学温度的诸方法中,辐射法即定点辐射系统是一个准确度很高,复现性非常好的辐射温度,热辐射功率及光辐照度的高水平标定和校准系统,在对标准光电高温计的校验和标定、传递温度量值,光辐照度的高水平传递以及黑体发射率的精确测定等方面已获广泛应用。因而,近几十年来已成为该领域研究的前沿和热点之一,在国际温标界受到越来越大的重视。 定点辐射系统的核心科学问题是金属固     

压电式阻抗头的标定

通过分析压电式阻抗头的结构及工作原理,同时利用实验室现有的中频振动标准装置,设计了此类传感器动态指标(参考灵敏度、频率响应、幅值线性度)的标定方法,并举例进行了标定方法的验证,保证了该类传感器量值传递的准确性。     

光谱失配对标定太阳电池产生的影响分析

标准太阳电池的短路电流可用来确定太阳模拟器的总辐照度强度。选取单晶硅、多晶硅、非晶硅薄膜和染料敏化4种常见类型的太阳电池,分别进行光谱响应度测量。对光谱匹配分别为A、B、C级的太阳模拟器进行光谱辐照度分布测量。利用光谱失配计算公式,并结合标准AM1.5G太阳光谱辐照度分布数据,理论计算出由于光源间光谱不匹配以及电池间光谱响应度不匹配所产生的光谱失配因子,并对标定太阳电池产生的影响进行了分析。     

基于误差反馈的LED阵列近场光强检测

发光二极管(LED)在机场、铁路等领域作为信号光源,通常采用多个LED组成阵列的方式.传统方法为拆卸后送入实验室中进行检测,此时无法获得光源在工作现场的状态且使得整个检测周期较长,针对上述问题提出一种基于照度误差的方法.在现场的近场区域内移动照度探头采集照度数据;再对各LED预设光强分布,计算此光强分布下在各测量点形成...     

A CMOS Time-of-Flight Range Image Sensor With Gates-on-Field-Oxide Structure

This paper presents a new type of CMOS time-of-flight (TOF) range image sensor using single-layer gates on field oxide structure for photo conversion and charge transfer. This simple structure allows the realization of a dense TOF range imaging array with 1515 mum² pixels in a standard CMOS process. Only an additional process step to create an n-type buried layer which is necessary for high-speed charge transfer is added to the fabrication process. The sensor operates based on time-delay dependent modulation of photocharge induced by back reflected infrared light pulses from an active illumination light source. To reduce the influence of background light, a small duty cycle light pulse is used and charge draining structures are included in the pixel. The TOF sensor chip fabricated measures a range resolution of 2.35 cm at 30 frames per second and an improvement to 0.74 cm at three frames per second with a pulsewidth of 100 ns.     

智能包装检测系统中光源波长研究

目的通过优化智能包装检测系统中的光源条件,提高多层包装中缺陷内衬纸智能检测的识别率和包装的良品率。方法在智能包装检测系统中,通过改变光源的波长来检测不同颜色的缺陷内衬纸,并对缺陷内衬纸面积检测的像素数量进行分析,来确定合适的光源波长。结果色相性导致红光、绿光及蓝光等可见单色光不能使相同颜色的内衬纸在智能包装检测系统中成像,但在白光、红外光和紫外光照射下可以检测出所有的缺陷内衬纸。进一步分析得知,智能包装检测系统在红外光照射下缺陷内衬纸的成像效果最好;在白光、红外光和紫外光照射下的识别率分别为90.5%, 99.5%, 96.5%,红外光照射下的识别率最高。结论在实际包装车间生产中,为使智能包装检测系统的准确率最高,可根据色相性选择光源或者直接选择红外光光源。     

Analyzing spatial coherence using a single mobile field sensor

According to the Van Cittert-Zernike theorem, the intensity distribution of a spatially incoherent source and the mutual coherence function of the light impinging on two wave sensors are related. It is the comparable relationship using a single mobile sensor moving at a certain velocity relative to the source that is calculated in this paper. The auto-corelation function of the electric field at the sensor contains information about the intensity distribution. This expression could be employed in aperture synthesis.     

彩色目标高维检测与空间分集检测技术

提出一种彩色目标高维检测和空间分集检测技术,它利用 RGB 颜色的均值趋同性校正色偏,减少光照强度和光源颜色对目标检测的影响;采用检测门限自适应变化的彩色目标高维检测算法检测出疑似目标,进一步避免了传统方法受环境光照影响大的缺点;使用基于区域关联性的彩色信号自适应空间分集检测技术,提高目标检测效果。试验证明,检测并降噪以后,97.5%以上的图像的提取结果可以达到 30db 以上的信噪比。     

基于机器视觉的内层包装缺陷检测光源的优化

目的 针对食品内层包装纸的缺陷特征,对机器视觉识别系统的照明光源进行优化,以提高内层包装缺陷的识别率,减少缺陷包装量。方法 基于计算机视觉识别技术,通过斑点检测不同光源下内层包装纸的常见缺陷特征,分别采用Matlab的三维绘图、相关性分析的方法,依次确定照明光源类型、形状和角度,并进行应用验证。结果 红外光源为纸铝复合内层包装纸缺陷特征识别的最适光源类型;条形光源与内层包装纸呈极显著相关,缺陷识别率达96.95%;60°的高角度照明位置与内层包装纸呈显著相关,缺陷识别率达96.96%。红外条形光源高角度照明,缺陷识别率达99%。结论 将红外条形光源高角度照明应用于纸铝复合内层包装纸的在线检测,与LED环形光源相比,其缺陷特征视觉识别率提高了0.51个百分点。     

Enhance Egocentric Grasp Recognition Based Flex Sensor Under Low Illumination

Egocentric recognition is exciting computer vision research by acquiring images and video from the first-person overview. However, an image becomes noisy and dark under low illumination conditions, making subsequent hand detection tasks difficult. Thus, image enhancement is necessary to make buried detail more visible. This article addresses the challenge of egocentric hand grasp recognition in low light conditions by utilizing the flex sensor and image enhancement algorithm based on adaptive gamma correction with weighting distribution. Initially, a flex sensor is installed to the thumb for object manipulation. The thumb placement that holds in a different position on the object of each grasp affects the voltage changing of the flex sensor circuit. The average voltages are used to configure the weighting parameter to improve images in the image enhancement stage. Moreover, the contrast and gamma function are used to adjust varies the low light condition. These grasp images are then separated to be training and testing with pre-trained deep neural networks as the feature extractor in YOLOv2 detection network for the grasp recognition system. The proposed of using a flex sensor significantly improves the grasp recognition rate in low light conditions.     

Microcrystalline silicon thin films for optical applications

Microcrystalline hydrogenated silicon thin films, deposited by the cyclic CVD method, were used for the production of bidimensional detectors. The optical detectors use a standard TCO/μc-p-i-n Si:H configuration as active device and two lateral ohmic contacts. Based on the lateral photovoltaic effect developed in the p-i-n structure under local illumination, we propose to develop a new sensing method for the recognition of a light pattern projected onto a p-i-n optical sensor. It was used strong spatially fixed light spots to simulate an image and a weak chopped light scanning-beam to make its recognition. The induced ac component of the lateral photovoltage was found to be dependent on the image position and intensity. A small signal circuit analysis and simulation is presented. Applications for image detection are discussed.     

Geometrical analysis of an optical fiber bundle displacement sensor

The performance of a multifiber optical lever was geometrically analyzed by extending the Cook and Hamm model [Appl. Opt. 34, 5854-5860 (1995)] for a basic seven-fiber optical lever. The generalized relationships between sensitivity and the displacement detection limit to the fiber core radius, illumination irradiance, and coupling angle were obtained by analyses of three various types of light source, i.e., a parallel beam light source, an infinite plane light source, and a point light source. The analysis of the point light source was confirmed by a measurement that used the light source of a light-emitting diode. The sensitivity of the fiber-optic lever is inversely proportional to the fiber core radius, whereas the receiving light power is proportional to the number of illuminating and receiving fibers. Thus, the bundling of the finer fiber with the larger number of illuminating and receiving fibers is more effective for improving sensitivity and the displacement detection limit.     

Sensitive Chemical Optic Sensor Using Birefringent Porous Glass for the Detection of Volatile Organic Compounds

A simple design involving a birefringent porous glass oriented between two crossed polarizers serves as the foundation for an optically based sensitive broad-spectrum chemical sensor. Volatile organic compounds (VOCs) such as acetonitrile vapors can be readily detected at concentrations of as low as 50 ppm. Changes are observed in polarized light transmitted by the anisotropic porous material constituting the sensor, upon exposure to VOC-bearing air, as intensity changes at a defined wavelength or as changes in spectral content (color) detectable by the eye. The optical effects resulting from exposure to various vapors are reversible and may result from adsorption of solvent vapors with attendant reduction of anisotropy. The microporous structure as well as the surface chemistry of the sensor may be controlled for tuning the response to VOCs for industrial applications. Miniaturization of the sensor using low-cost materials such as plastic or glass optical fibers, Polaroid films, and birefringent porous glass is demonstrated. The sensor described in this paper could use ambient light as source and the eye as detector (color change) or electronically controlled light emission and detection for better sensitivity and real time monitoring of VOCs. Such intrinsic explosion proof sensors could be used to safely monitor VOC levels in remote environments.