A new manufacturable filter design approach for spectral reflectance estimation

Selection of the best possible filter set among a set of available filters is the obvious method of increasing dimension of camera signals for spectral reflectance reconstruction. There are also methods that are focusing on the filter design regardless of noticing to the constructability of the designed filters. This study shows that direct optimization of physical variables of filter manufacturing technique is more reliable than indirect approach of designing and then physical manufacturing of the designed filters. Direct optimization of the transmission‐controlling primaries in filter manufacturing process would guarantee having the designed filters in reality. Combination of some solvent dyes was used as the spectral transmission matching system for filter manufacturing. As a conventional technique, filters were designed and best possible dye concentrations that match the desired filters were calculated. As an alternative approach, filters were also designed using direct optimization of dyes concentrations. The results showed that direct optimization of dye concentrations exhibits better performance in comparison with the conventional technique. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 316–326, 2017     

基于非下采样三通道不可分对称小波的多光谱图像融合

针对IHS变换融合方法不能保持好的光谱信息,张量积小波变换融合方法生成的融合结果图像空间分辨率偏低、且易产生方块效应等不足.提出了一种基于三通道不可分对称小波的多光谱图像融合方法.利用矩阵扩充的方法,给出了三通道不可分对称小波滤波器组的构造方法,用所构造的不可分小波滤波器组分别对多光谱图像的亮度分量和全色图像作非下采样...     

带对准光路的激光细胞穿孔显微物镜设计

针对近红外光谱可对活体组织进行无损伤穿孔,并解决在穿孔中需要重新对焦的问题,通过Zemax软件对7片式前置光阑显微物镜结构在0.48~1.48?m波长范围内进行了宽光谱消色差的优化设计。设计实现了像距为无限远的多光谱共焦成像,其放大倍率为40,数值孔径0.5,最大焦面漂移量仅为27?m,可见光波段在空间频率为350 lp/mm时,0.7视场的MTF>0.5,具有较高的分辨力。并且在波长1480 nm处,MTF值接近衍射极限,具有较高的能量,满足细胞穿孔的要求。文中还给出了实验结果,并预测其应用前景。     

低成本便携式多光谱成像系统的研发及优化

目的 针对现有多光谱成像系统存在成本高、结构复杂、操作难度大和响应速度慢等问题。因此，本文提出了一种基于脉冲调制的低成本便携式多光谱成像系统，并采用客观图像质量评估（image quality assessment，IQA）的方法对其系统参数进行优化。方法 该系统主要由光源模块、控制模块、图像采集模块和图像分析模块4部分组成。光源模块采用9个波长的LED （light emitting diode）阵列，其中心波长为365 nm、390 nm、460 nm、515 nm、585 nm、620 nm、650 nm、730 nm和840 nm；控制模块主要包括LED驱动电路和USB （universal serial bus）电源，可以通过发送一定时间间隔的脉冲波来分时点亮LED，并通过一定阻抗匹配使LED发光强度达到最大值；图像采集模块主要使用去除红外截止滤波片的高清红外工业相机，该相机的最佳光谱感应范围包含所选的9个LED灯珠的中心波长；图像分析模块主要执行客观图像质量评估算法。系统执行时，STC89C51单片机发射周期为T的脉冲波来驱动9种不同波长的LED分时点亮。然后，计算机平台调用高清红外相机模组，以相匹配的间隔捕获多光谱图像。在系统拍摄参数优化实验中，本文采用模糊度和清晰度评价指标对所获得的多光谱图像从相机拍摄时间间隔、相机拍摄距离和光照强度3个角度进行质量评估，进而获得较优的系统成像参数。结果 通过改变系统拍摄参数，对3个场景下的不同拍摄条件所获取的多光谱图像质量进行评估，结果显示：对于本文所搭建的多光谱成像系统，相机拍摄时间间隔与LED灯珠频闪周期同步，拍摄距离为25 mm，光照强度为45 Lux下成像质量相对较好。结论 本文设计并搭建的基于脉冲调制的低成本便携式多光谱成像系统成本低、操作难度小、结构简单、成像质量较好、成像速度较快，可以满足多光谱成像系统大规模推广使用的要求。此外，本文的系统设计方法、设计思路和实验方案等可以为后续研究提供借鉴。     

基于交叉累计剩余熵的多谱磁共振图像配准

针对传统互信息(MI)图像配准容易产生局部极值的问题,提出一种基于交叉累计剩余熵(CCRE)的多谱磁共振图像配准方法.首先,将参考和浮动图像压缩至5位和7位灰度级;然后,采用哈宁窗Sinc插值计算5位灰度图像的CCRE,并用Brent算法搜索CCRE得到预配准的变换参数;最后,从该变换参数出发,采用部分体积(PV)插值计算7位灰度图像的CCRE,用Powell算法进行优化,得到最终的变换参数.实验结果表明,该方法的鲁棒性相比直接采用PV插值的CCRE配准得到提高;配准时间比直接采用哈宁窗Sinc插值的CCRE配准节省了90%左右,且配准精度有所提高.该方法兼顾了鲁棒性、效率和精度,适合用于多谱图像配准.     

基于多光谱成像技术的宣纸形态学特征分析

国画艺术品的科技取证与鉴别受到各领域的关注。宣纸作为国画的重要载体,其特征提取和分析方法有较高的研究意义。本文使用多光谱成像技术对宣纸进行形态学特征分析。实验采用多光谱成像系统获取宣纸在不同波长通道下的光谱图片,继而采用纹理参数统计对光谱图像进行测量,获得宣纸特征的敏感波段;采用数学形态学和灰度统计原理建立宣纸形态学特征分析模型,得到一维特征向量。为了评价特征向量的准确度,实验将特征向量输入到支持向量机（SVM）分类器进行检测分类。结果表明,宣纸的差异化特征在550nrn波段下最为明显;由模型输出的特征向量分类正确率为96％。本文提出的宣纸分析模型能够将大部分种类的宣纸特征准确提取,并具有一定的高效性。     

Recovering spectral data from natural scenes with an RGB digital camera and colored filters

Many spectral‐recovery methods using RGB digital cameras assume the underlying smoothness of illuminant and reflectance spectra, and apply low‐dimensional linear models. The aim of the present work was to test whether a direct‐mapping method could be used instead of a linear‐models approach to recover spectral radiances and reflectances from natural scenes with an RGB digital camera and colored filters. In computer simulations, a conventional RGB digital camera with up to three colored filters was used to image scenes drawn from a hyperspectral image database. Three measures were used to evaluate recovery with the direct‐mapping method: goodness‐of‐fit, root‐mean‐square error, and a color‐difference metric. It was found that with two and three filters both spectral radiances and reflectances could be recovered sufficiently accurately for many practical applications. With little increase in computational complexity, an RGB camera and a few colored filters can provide significantly better recovery of natural scenes than an RGB camera alone. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 352–360, 2007     

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     

Research on Gaussian distribution preprocess method of infrared multispectral image background clutter

This paper introduces a sliding-window mean removal high pass filter by which background clutter of infrared multispectral image is obtained. The method of selecting the optimum size of the sliding-window is based on the skewness-kurtosis test. In the end, a multivariate Gaussian distribution mathematical expression of background clutter image is given.