单通道三波段彩色夜视系统设计及实验研究

针对目前微观夜视仪器产生单色图像的缺陷,提出了一种单通道三波段的彩色夜视方案。简要介绍了单通道三波段彩色夜视系统的工作原理,重点论述了该系统的设计方法,并对滤光片的光谱透过率、色轮的窗口数量、荧光屏与CCD光电阴极的耦合方式等问题进行了计算和分析。在单通道三波段彩色夜视系统装置研制基础上,开展了彩色夜视实验,成功得到色彩较为真实的夜视图像。     

CCD彩色滤光片的制备与集成技术研究

介绍了彩色CCD的器件结构和成像原理,采用彩色光刻胶光刻法实现了彩色滤光片的制备,并通过分析彩色滤光片缓冲层、滤光片厚度和固化工艺等对滤光片性能的影响,获得了彩色滤光片的片上集成技术,并将其集成在512×512帧转移CCD器件上,完成了性能评价与成像验证.测试结果表明:制备的彩色滤光片主线透过率大于80％,光谱串扰小于15％,色纯度大于75％,集成该滤光片的彩色CCD成像色彩空间与sRGB相当,能够满足大多数CCD相机彩色成像的要求.     

由光谱响应选择红外探测器滤光片

通过对SPR制冷型InSb红外光伏探测器相对光谱相应的测试及滤光片透过率谱的测试,发现了场镜、滤光片、红外探测器组合件的光谱响应同滤光片技术条件的关系和差别.     

太阳模拟器AM0型滤光片及其稳定性研究

太阳模拟器作为航天科技卫星空间环境模拟和太阳能电池检测与标定的必要模拟设备,越来越受到人们的关注。太阳模拟器滤光片作为模拟器的核心部件,通过对模拟器光源滤光,可以得到不同的太阳光谱辐照度。文中研究的AM0滤光片通过对氙灯光源滤光,可以得到大气层表面的太阳光谱辐照度分布。根据标准AM0光谱辐照度曲线和标准氙灯辐照度曲线,得到AM0滤光片透过率曲线。在此基础上对滤光片进行膜系设计和镀制,得到了满足国标A类标准的AM0滤光片。对滤光片进行了紫外辐照实验和高温烘烤实验,研究了其光学稳定性,所镀制的滤光片光学稳定性优于目前使用的滤光片。     

三波段真彩色夜视光谱匹配技术

为了得到夜晚目标的真实色彩信息,设计了三波段真彩色夜视系统,并阐述了其工作原理。根据满月条件下月光的光谱特性,结合典型目标的光谱反射特性和S25+光电阴极的光谱响应特性,采用对比度反转最大原则,综合考虑人眼的光谱光视效率特性,提出了三波段真彩色夜视技术的光谱分割方法。依据光谱匹配的理论计算结果制备了滤光片,并对滤光片的光谱透过率进行了测量。利用制备的滤光片进行了实验并提出了一种三波段夜视图像彩色融合方法,实验表明:提出的光谱分割方法能够较好地还原目标的真实色彩。     

1～3毫微米半宽的衬度介质窄带干涉滤光片光学性能的研究

研究了用硫化锌和冰晶石制的17～41层衬度介质窄带干涉滤光片光谱透过曲线的特点。文中指出,峰值透过率T_(max)的降低,是由于组成这种滤光片的各单元滤光片透过峰值波长λ_(max)位置的不匹配造成。研究了干燥和未干燥的空气、氮、氧及氦对这种滤光片光学特性的影响。结果表明,短时间与氦接触对滤光片参数有良好影响,而湿气则引起滤光片的λ_(max)位移、T_(max)变化及透过带变形等。隔绝滤光片不与湿气相接触可使光谱曲线的位置和形状达到稳定。     

基于CIEDE2000的透明品红色塑料小色差检测研究

采用分光光度计对透明有色塑料在各个波长的透射率进行测定,选取D65照明体与CIE1964补充标准观察者光谱三刺激值,在此基础上分别采用CIE1976LAB与CIEDE2000色差计算公式,把各自的计算结果与人眼实际视觉效果进行比较。实验结果证明,CIEDE2000色差公式更加能够反映出产品的实际色差指标,更加符合人眼的视觉特征。     

低损耗1064 nm带通滤光片多层膜的散射特性研究

1064 nm Nd∶YAG激光器在医疗领域应用广泛,而1064 nm带通滤光片作为激光器的关键器件对低损耗薄膜提出了更高要求。本文在相同粗糙度的K9基底上,采用TiO_2与SiO_2两种材料以相同氧分压和不同氧分压的方式借助离子辅助制备了1064 nm带通滤光片薄膜。使用分光光度计对薄膜的透过光谱进行表征,光谱特性显示,采用相同氧分压制备的薄膜的透过率较好。利用轮廓仪与扫描电镜分别对薄膜粗糙度以及切面形貌进行表征,结果表明,采用相同氧分压制备的薄膜具有光滑的表面和较规整的膜层。通过软件拟合分析得到了透过率的降低来源于散射的结论。当两种材料的氧分压不同时,镀膜过程中真空度交替切换会导致考夫曼离子源离子束流不稳定,进而导致层间粗糙度增加,从而引起了散射。基于标量散射理论,推导了相关和非相关散射情况下多层膜透过率的计算公式,并利用此公式对两种不同工艺制备的薄膜的透过率进行拟合,结果发现理论计算曲线与实际测试光谱曲线基本一致。     

激光束强度的均匀化

一般TEM_(OO)模振荡的激光束断面强度呈高斯分布,因此不能得到均匀的照明光。为了得到强度一样的照明光,有人提出用透过率为反高斯分布(中央的透过率低)的滤光片。资料〔3〕用中性密度玻璃制成平凸透镜,进行了使准直透镜具有这种滤光片性能的试验,得到了5％以内的均匀光束。但是,用此方法在满足滤光片特性的同时又要满足准直透镜的特性,这样由于设计上受到玻璃材料特性的限制,而且中性密度玻璃的最佳浓度的调节以及透镜的研磨等都不是很容易做到的。     

红外微型多谱段集成滤光片产品质量考核方法

作为空间红外相机上的关键部件,微型集成滤光片得到越来越广泛的应用。由于制作工艺复杂,加上探测器内部工作条件极为苛刻,滤光片在使用中经常出现诸多问题。为了在地面阶段全面暴露滤光片质量缺陷并针对性解决这些问题,减少相机在轨工作风险,文章提出一套适用于空间红外相机的多谱段集成滤光片产品质量考核方法,涵盖产品外观检查、结构尺寸测试、面形检测、光谱性能测试、膜层质量检查,环境试验考核、力学试验考核等方面,旨在滤光片研制过程中能够全面、准确地考核集成滤光片产品质量,减少产品使用中的潜在风险。     

准积分法构建视觉可感知三维色域的研究

为了更全面地评价显示器的色重显性能,用准积分法构建了人类视觉可感知三维色域.该算法用CIE标准色度观察者观察、混配等能单色辐射测得的CIE 1931 XYZ色度系统光谱三刺激值,按某一波长间隔求累加和,来近似实现未知函数表达式的多重积分运算.构建的色域囊括了人眼能识别的全部颜色,是宽色域、高动态范围显示设备的目标色域.还用三棱锥体积求和算法计算出该色域体积,验证了算法的可行性.进而由实测的LCD电视显示器数据,用同样方法计算其三维色域,并与视觉可感知三维色域进行定量比较.这些工作表明,本算法可为定量评价显示器的三维色域提供理论依据和可行算法,用这种方法给出的显示设备三维色域覆盖率可克服通常在二维色度图计算色域覆盖率的局限性.     

A subspace matching color filter design methodology for a multispectral imaging system.

In this paper, we present a methodology to design filters for an imaging system to improve the accuracy of the spectral measurements for families of reflective surfaces. We derive the necessary and sufficient conditions that the sensor space of the system must obey in order to measure the spectral reflectance of the surfaces accurately. Through simulations, we show how these conditions can be applied to design filters using a set of sample spectral data acquired from extracted teeth. For this set of data, we also compare our results to those of Wolski's method, a conventional filter design method which produces filters that recover tristimulus values of surfaces accurately under several illuminants. We show that our method produces filters that capture the spectral reflectance better given the same number of measurements. The errors in predicting the color of the sample data are much lower under every test illuminant when the filters designed with our method are used.     

Spatio-spectral color filter array design for optimal image recovery

In digital imaging applications, data are typically obtained via a spatial subsampling procedure implemented as a color filter array-a physical construction whereby only a single color value is measured at each pixel location. Owing to the growing ubiquity of color imaging and display devices, much recent work has focused on the implications of such arrays for subsequent digital processing, including in particular the canonical demosaicking task of reconstructing a full color image from spatially subsampled and incomplete color data acquired under a particular choice of array pattern. In contrast to the majority of the demosaicking literature, we consider here the problem of color filter array design and its implications for spatial reconstruction quality. We pose this problem formally as one of simultaneously maximizing the spectral radii of luminance and chrominance channels subject to perfect reconstruction, and-after proving sub-optimality of a wide class of existing array patterns-provide a constructive method for its solution that yields robust, new panchromatic designs implementable as subtractive colors. Empirical evaluations on multiple color image test sets support our theoretical results, and indicate the potential of these patterns to increase spatial resolution for fixed sensor size, and to contribute to improved reconstruction fidelity as well as significantly reduced hardware complexity.     

Filter considerations in color correction

The quality of color correction is dependent on the filters used to scan the image. This paper introduces a method of selecting the color filters using a priori information about the viewing illuminants. Color correction results using the derived filters are compared with color correction results using filters that are optimal for individual viewing and recording illuminants. The comparison is performed using the CIE PEL (L*a*b*) perceptual color difference measure. Applications of this work are found in the design of scanners, copiers, and television systems.     

多角度光谱测量法制备短波通滤光膜技术

详细论述了短波通滤光膜的理论设计与实际制备结果,光谱曲线偏离的原因及修正方法。首先选择高、低折射率膜料设计短波通滤光膜系,然后进行实际膜系制备。由于镀膜机存在控制误差,使得实际膜层制备厚度偏离理论厚度,导致实际制备光谱曲线超差。通过利用多角度光谱测量法对制备结果进行测量,依据多次测量结果的曲线偏离量,判断产生膜层厚度误差的膜料、膜层厚度误差的偏差大小及方向。在修正膜层厚度误差后,制备了光谱曲线平坦变化的短波通滤光膜。这种光谱性能更好的短波通滤光膜可以避免光学系统的偏色效应,此项技术为短波通滤光膜的设计与加工提供了新的理论依据与制备方案。     

基于光谱重建技术的壁画颜色复原与评价

为了在给定的照明和观察条件下，用相机响应信号重建物体表面光谱反射率，实现颜色的高精度复原，采用了多光谱成像技术采集物体表面的多光谱图像，使用主成分分析、 R 矩阵和正则化 R 矩阵方法进行了光谱反射率重建的理论研究，并对壁画色块颜色复原进行了实验验证，取得了壁画色块的重建光谱和颜色复原数据，同时对基于正则化 R 矩阵方法的壁画色块颜色复原结果进行了评价。结果表明，正则化 R 矩阵方法进行光谱重建的光谱精度和色度精度更高，与主成分分析和 R 矩阵方法相比，色差降低了0.0732，适应度系数提高了1.10%，均方根误差降低了0.0035，光谱匹配偏指数降低了0.0225。该方法能够满足高精度颜色再现的需要，适用于文物艺术品数字化存档、文物艺术品修复等领域。     

Inversion of ocean color observations using particle swarm optimization

Inversion of ocean color reflectance measurements can be cast as an optimization problem, where particular parameters of a forward model are optimized in order to make the forward-modeled spectral reflectance match the spectral reflectance of a given in situ sample. Here, a simulated ocean color dataset is used to test the capability of a recently introduced global optimization process, particle swarm optimization (PSO), in the retrieval of optical properties from ocean color. The performance of the PSO method was compared with the more common genetic algorithms (GA) in terms of model accuracy and computation time. The PSO method has been shown to outperform the GA in terms of model error. Of particular importance to ocean color remote sensing is the speed advantage that PSO affords over GA.     

Optimization of sensor response functions for colorimetry ofreflective and emissive objects

This paper describes the design of color filters for a surface color measurement device. The function of the device is to return the XYZ tristimulus vector characterizing the color of the surface. The device is designed to measure emissive as well as reflective surfaces. It uses an internal set of LEDs to illuminate reflective surfaces while characterizing their color under assumed standard illuminants. In the design of the filters, we formulate a nonlinear optimization problem with the goal of minimizing error in the uniform color space CIE L*a*b*. Our optimization criteria employs a technique to retain a linear structure while approximating the true L*a*b* error. In addition, our solution is regularized to account for system noise, filter roughness, and filter implementation errors. Experimental results indicate average and worst-case device accuracy of 0.27 L*a*b* DeltaE units and 1.56 L*a*b* DeltaE units for a "system tolerance" of 0.0005.     

A multiscale representation including opponent color features fortexture recognition

We introduce a representation for color texture using unichrome and opponent features computed from Gabor filter outputs. The unichrome features are computed from the spectral bands independently while the opponent features combine information across different spectral bands at different scales. Opponent features are motivated by color opponent mechanisms in human vision. We present a method for efficiently implementing these filters, which is of particular interest for processing the additional information present in color images. Using a data base of 2560 image regions, we show that the multiscale approach using opponent features provides better recognition accuracy than other approaches.     

基于CIE1931的颜色识别方法研究

在国际照明委员会(CIE)的标准协议规定下,通过色彩与波长的对应关系,通过计算斜率,使用线性插值方法计算了颜色所对应的主波长及其饱和度,实现了颜色的辨别,并使用Matlab仿真再现了光谱三刺激值曲线、等能光谱色亮度曲线、舌形色度图。