Optical tomography system based on charge-coupled device linear image sensors: Particle size measurement

This paper discussed an optical tomography system based on charge-coupled device (CCD) linear image sensors. The developed system consists of a lighting system, a measurement section and a data acquisition system. Four CCD linear image sensors are configured around a flow pipe with an octagonal-shaped measurement section, for a four projections system. The four CCD linear image sensors consisting of 2048 pixels with a pixel size of 14 μm by 14 μm are used to produce a high-resolution system. A simple optical model is mapped into the system's sensitivity matrix to relate the optical attenuation due to variations of optical density within the measurement section. A reconstructed tomographic image is produced based on the model using MATLAB software. The designed instrumentation system is calibrated and tested through different particle size measurements from different projections.     

一种基于B样条曲面的深度图像重抽样方法

银行深度图像处理中由于等角测距造成的几何失真,根据非等网格深度数据的数值特点,文中提出了一种基于B样条曲面的深度图像重抽样方法,并且与其它一些三维插值方法进行了精度比较。该文利用真实深度图像进行了重抽样实验,结果表明,基于B样条曲面的重抽样方法有效地克服了原始图像数据中存在的几何失真以及测量噪声,为后续的三维表面处理提供了更为精确的三维网格深度数据。     

Convolutional Sparse Coding for High Dynamic Range Imaging

Current HDR acquisition techniques are based on either (i) fusing multibracketed, low dynamic range (LDR) images, (ii) modifying existing hardware and capturing different exposures simultaneously with multiple sensors, or (iii) reconstructing a single image with spatially‐varying pixel exposures. In this paper, we propose a novel algorithm to recover high‐quality HDRI images from a single, coded exposure. The proposed reconstruction method builds on recently‐introduced ideas of convolutional sparse coding (CSC); this paper demonstrates how to make CSC practical for HDR imaging. We demonstrate that the proposed algorithm achieves higher‐quality reconstructions than alternative methods, we evaluate optical coding schemes, analyze algorithmic parameters, and build a prototype coded HDR camera that demonstrates the utility of convolutional sparse HDRI coding with a custom hardware platform.     

基于多传感器的光电监视系统设计

针对成像系统的传感器日益增多、成像过程越来越复杂,获取的图像数据急剧增加,其系统设计难度不断增加的问题,文中提出一种基于多传感器的数字成像系统。采用三个摄像机共用光路,实现无需图像配准即可得到同一视场的同一时刻图像;通过千兆网传输图像,解决了以往数字图像传输过程中连线过多问题;因为不同传感器的成像特点不同,应用一种改进的双边滤波技术对异源图像进行融合,融合图像质量优于各波段图像,进一步提高了光电监视水平。     

基于PCI Express总线的高帧频CMOS相机图像采集系统设计

基于PCI Express总线设计了一种高帧频CMOS相机图像采集系统。选用帧频250帧/s的LUPA-300作为高帧频图像传感器,通过FPGA实现对图像传感器的参数配置与图像数据处理,采用PCI Express总线作为图像数据传输总线,大大提高了传输速度。实验结果表明该系统结构简单、成像清晰稳定、拍摄速度快,可应用于高速目标的拍摄。     

Offner成像光谱仪的设计与航拍实验

介绍一种Offner结构高分辨率推扫式成像光谱仪的设计,包括光学结构设计、数据获取与存储系统配置、基于数据库的光谱图像拼接软件设计以及成像光谱仪波长标定和辐射标定方法.其次介绍成像光谱仪在青藏高原陆面敏感因子航空遥感实验中的使用情况,包括实验概况、成像光谱仪及其采集系统在机舱内的安装调试、光谱仪的航拍参数以及航带光谱图像的拼接处理,最终获取到高分辨率的高光谱图像立方体.仪器的首次航拍飞行实验取得预期成果.     

用强度系列成象法获取或显示高动态范围图象

提出一种适合于高动态范围图象的获取和显示的强度系列成象法。改变输入图象的强度，微机控制的图象采集系统进行记录得到一组磁盘文件，形成强度图象系列。基于记录的系列图象，可以进行信息提取、变换和显示等操作。基于获得的图象系列，提出一种剪贴操作进行快速的非线性图象变换。给出对光学功率谱处理的一个实例，它相当于进行锯齿形的非线性变换。     

图像采集系统的面阵CCD驱动电路设计

详细介绍了基于面阵CCD器件的图像采集系统的构成,通过对CCD图像传感器ICX424AQ的驱动时序及数模转换芯片AD9943转换时序的分析,设计了用于图像采集的CCD驱动电路,并采用FPGA进行了实现。采用双线性插值算法,从表面覆盖Bayer彩色滤波阵列的CCD图像传感器获得全彩图像,图像数据以DVI格式实时发送到LCD屏上显示。     

Robot vision: An evaluation of imaging sensors

Robot vision, robotics vision, and computer vision are terms that have evolved over the past few years to include two separate but related functions that provide visual sensing for computerdriven robots. These two functions are “electro-optical imaging” and “image processing.” The purpose of electro-optical imaging is to convert optical radiation to an appropriate electronic signal for input to the robot's computer; whereas, the purpose of image processing is to extract useful information from the electronic image provided by the sensor. This article deals with the electro-optical sensing part of robot vision. It describes the operation and properties of electro-optical imaging sensors. The fundamental concepts of optical radiation, optical radiation quantities and units, and photon energies are defined. The fundamental principles for detecting optical radiation and definitions for the primary performance measures for optical detectors are given. A relatively comprehensive overview of the parameters used to describe imaging sensors is presented. Factors affecting these parameters and obtainable sensor performance are compared. Example design analyses are presented to show the interaction of various performance measures.     

计算成像前沿进展

计算成像是融合光学硬件、图像传感器和算法软件于一体的新一代成像技术,突破了传统成像技术信息获取深度(高动态范围、低照度)、广度(光谱、光场、3维)的瓶颈。本文以计算成像的新设计方法、新算法和应用场景为主线,通过综合国内外文献和相关报道来梳理该领域的主要进展。从端到端光学算法联合设计、高动态范围成像、光场成像、光谱成像、无透镜成像、低照度成像、3维成像和计算摄影等研究方向,重点论述计算成像领域的发展现状、前沿动态、热点问题和趋势。端到端光学算法联合设计包括了可微的衍射光学模型、折射光学模型以及基于可微光线追踪的复杂透镜的模型。高动态范围光学成像从原理到光学调制、多次曝光、多传感器融合以及算法等层面阐述不同方法的优点与缺点以及产业应用。光场成像阐述了基于光场的3维重建技术在超分辨、深度估计和3维尺寸测量等方面国内外的研究进展和产业应用,以及光场在粒子测速及3维火焰重构领域的研究进展。光谱成像阐述了当前多通道滤光片,基于深度学习和波长响应曲线求逆问题,以及衍射光栅、多路复用和超表面等优化实现高光谱的获取。无透镜成像包括平面光学元件的设计和优化,以及图像的高质量重建算法。低照度成像包括低照度情...     

一种新的光学遥感器优化设计方法

针对高分辨率空间光学遥感器,既要实现轻小型化,又要获得高品质遥感图像的要求,本文提出一种基于成像链路仿真的遥感器优化设计方法。文章以MTF和噪声模型为基础分析成像链路中的各个环节对成像质量的影响,同时考虑末端图像复原处理,构建成像链路仿真模型,通过遥感器指标评价和仿真图像质量评价来优化遥感器的总体指标,从而在保证成像质量的同时降低遥感器研制难度。实验验证了优化设计方法的可行性和优势。     

无方向数据采集的相控阵结构健康监测研究

超声相控阵结构健康监测过程中由于按角度扫描的数据采集持续时间长,结构损伤前后采集的数据易受环境和结构变化的影响,针对这一问题,提出无方向数据采集的相控阵结构健康监测成像定位方法。基于相控阵方法,对采集后数据根据发射和接收过程进行时间延迟的计算,然后将监测结果进行二维成像。该方法在玻璃纤维复合材料板结构上的实验研究证明,采用无方向数据采集的相控阵结构健康监测方法能够精确监测结构中损伤并对损伤进行清晰成像;并且该方法可以大大缩短监测时间,从而使监测过程不受环境条件变化的影响,为超声相控阵监测方法的工程化奠定基础。     

相控阵三维声呐信号采集与处理系统

高精度三维成像声呐的实现需要完成大规模信号同步采集和海量数据并行计算,为此,提出基于现场可编程逻辑门阵列的并行计算系统。在使用同源时钟的前提下,利用Spartan-3对平面阵2304路换能器信号进行同步采样,通过离散傅里叶变换降采样以减小采样数据规模,采用Virtex-5重新计算换能器权重以降低运算量,使用分步的波束形成算法以减小系统所消耗的存储器规模,同时在PC上实现三维图像实时显示。实验结果证明了该系统的可行性。     

遥感图像恢复与遥感器MTF 在轨检测技术

遥感成像过程受到大气和成像系统中的光学、探测器和电子学子系统等的影响, 引起成像退化作用, 造成图像模糊, 降低了图像中信息的提取能力。图像恢复技术可以改善图像的质量, 提高图像信息提取能力。依据图像恢复技术的要求, 高精度成像系统调制传递函数(MTF) 是高质量图像恢复的基本条件。针对不同遥感器之间、同一遥感器不同时期存在的成像性能变化, 所引起成像系统MTF 变化的实际情况, 介绍了成像过程中系统MTF 在轨运检测方法。着重于介绍刃边法, 对刃边法的原理、刃边法检测对地物景观的要求等进行了详细分析, 对这一方法中有关图像景物的行扫描采样、扫描行的配准以及对所获得的边扩散函数的拟合等关键技术进行了详细介绍, 这些技术是保证较高精度获取遥感图像MTF 的基础。文章在介绍基于成像系统MTF 图像恢复技术后, 通过实验检验了方法的可行性, 结果表明以MTF 在轨检测为基础的图像恢复技术, 可以明显地提高遥感图像质量。     

黑河综合遥感联合试验中机载WiDAS数据的预处理方法

机载红外广角双模式成像仪(Wide-angle Infrared Dual-mode line/area Array Scanner\|WiDAS)是黑河综合遥感联合试验中的主要机载传感器之一,它通过可见光到热红外波段的广角成像,获取地表二向反射和热辐射方向性信息,介绍了WiDAS数据的预处理关键算法及关键参数。WiDAS传感器的可见近红外波段与中红外、热红外波段在探测器性能、空间分辨率和目标辐射特性方面都有显著差异,因此它们的预处理具有不同的算法。可见近红外波段的CCD相机用积分球定标,用简单的多项式形变函数进行波段间配准,用6S模型和实测气溶胶光学厚度进行大气校正。中红外、热红外波段的红外相机则用面元黑体定标,波段配准中采用了复合的形变函数和较为复杂的配准算法,大气校正采用MODTRAN模型和实测大气廓线。还介绍了从WiDAS标准预处理产品中提取目标的多角度观测的方法,这些信息为使用WiDAS数据产品开展定量遥感研究和应用提供参考。     

Generalized Mosaicing: High Dynamic Range in a Wide Field of View

We present an approach that significantly enhances the capabilities of traditional image mosaicking. The key observation is that as a camera moves, it senses each scene point multiple times. We rigidly attach to the camera an optical filter with spatially varying properties, so that multiple measurements are obtained for each scene point under different optical settings. Fusing the data captured in the multiple images yields an image mosaic that includes additional information about the scene. We refer to this approach as generalized mosaicing. In this paper we show that this approach can significantly extend the optical dynamic range of any given imaging system by exploiting vignetting effects. We derive the optimal vignetting configuration and implement it using an external filter with spatially varying transmittance. We also derive efficient scene sampling conditions as well as ways to self calibrate the vignetting effects. Maximum likelihood is used for image registration and fusion. In an experiment we mounted such a filter on a standard 8-bit video camera, to obtain an image panorama with dynamic range comparable to imaging with a 16-bit camera.     

Parallel Image Reconstruction in Real-Time Ultrasound Process Tomography for Two-phased Flow Measurements

This paper investigates different parallel-processing architectures as a means of achieving real-time ultrasound tomographic imaging capability. The real-time numerical image reconstruction is implemented by a parallel processor network and DSP controlled data acquisition electronics. The parallel imaging technique developed for the present work has been shown to be capable of achieving the necessary real-time image generation rate (100 frames per second on a 100 × 100 image array for software image reconstruction) and an average update frequency of 30 frames per second when acquiring data from the hardware. The parallel image processing algorithm which combines geometric and algorithmic parallelism aiming at optimizing the parallel efficiency of the processors of the array has been implemented and verified. The experimental imaging results generated by the parallel imaging system are presented and the dynamic performance of the parallel system are discussed.     

Range map superresolution-inpainting,and reconstruction from sparse data

Range images often suffer from issues such as low resolution (LR) (for low-cost scanners) and presence of missing regions due to poor reflectivity, and occlusions. Another common problem (with high quality scanners) is that of long acquisition times. In this work, we propose two approaches to counter these shortcomings. Our first proposal which addresses the issues of low resolution as well as missing regions, is an integrated super-resolution (SR) and inpainting approach. We use multiple relatively-shifted LR range images, where the motion between the LR images serves as a cue for super-resolution. Our imaging model also accounts for missing regions to enable inpainting. Our framework models the high resolution (HR) range as a Markov random field (MRF), and uses inhomogeneous MRF priors to constrain the solution differently for inpainting and super-resolution. Our super-resolved and inpainted outputs show significant improvements over their LR/interpolated counterparts. Our second proposal addresses the issue of long acquisition times by facilitating reconstruction of range data from very sparse measurements. Our technique exploits a cue from segmentation of an optical image of the same scene, which constrains pixels in the same color segment to have similar range values. Our approach is able to reconstruct range images with as little as 10% data. We also study the performance of both the proposed approaches in a noisy scenario as well as in the presence of alignment errors.     

一种嵌入式多业务农情信息无线获取节点开发

精细农业应用领域中的农情信息获取设备种类繁多,输入输出接口多样,但是功能相对单一,可扩展性有待提高.为此,设计一种基于Android操作系统的多业务农情信息获取节点,以展讯SC7731G为主控芯片,结合ADC接口、麦克风、图像传感器以及WiFi和3G无线通信模块等,实现基于文本、音频、图像/视频等多业务农情信息的一体化快速采集和无线传输.为了验证节点的农情信息采集功能和无线传输性能,在室内外环境中进行了基于土壤湿度、音频、图像及视频的数据采集试验,通过3G移动网络传输音频数据,平均速率达到21 kbyte/s;通过WiFi局域网传输图像和视频数据,平均速率可达到2.63 Mbyte/s.试验结果表明,节点能够通过ADC接口外接文本数据传感器,具备良好的音频、图像及视频采集功能,能够满足精细农业对多业务农情信息的快速获取和无线传输需要.     

Multiscale Fusion of Visible and Thermal IR Images for Illumination-Invariant Face Recognition

This paper describes a new software-based registration and fusion of visible and thermal infrared (IR) image data for face recognition in challenging operating environments that involve illumination variations. The combined use of visible and thermal IR imaging sensors offers a viable means for improving the performance of face recognition techniques based on a single imaging modality. Despite successes in indoor access control applications, imaging in the visible spectrum demonstrates difficulties in recognizing the faces in varying illumination conditions. Thermal IR sensors measure energy radiations from the object, which is less sensitive to illumination changes, and are even operable in darkness. However, thermal images do not provide high-resolution data. Data fusion of visible and thermal images can produce face images robust to illumination variations. However, thermal face images with eyeglasses may fail to provide useful information around the eyes since glass blocks a large portion of thermal energy. In this paper, eyeglass regions are detected using an ellipse fitting method, and replaced with eye template patterns to preserve the details useful for face recognition in the fused image. Software registration of images replaces a special-purpose imaging sensor assembly and produces co-registered image pairs at a reasonable cost for large-scale deployment. Face recognition techniques using visible, thermal IR, and data-fused visible-thermal images are compared using a commercial face recognition software (FaceIt^®) and two visible-thermal face image databases (the NIST/Equinox and the UTK-IRIS databases). The proposed multiscale data-fusion technique improved the recognition accuracy under a wide range of illumination changes. Experimental results showed that the eyeglass replacement increased the number of correct first match subjects by 85% (NIST/Equinox) and 67% (UTK-IRIS).