视频判读系统分析

本文就光电测量提出了以CCD进行视频捕获,将获得的视频图象通过采集卡滤波、A/D转换为数字图象,存储在计算机内存中,根据具体要求选择相应的算法,由计算机对其进行分析处理.     

X射线三维图象显示

本文介绍的X射线三维图象显示装置是根据双目视差原理,借助于电子学及光学的方法,将不可视的X射线图象转变为可视的立体图象的装置。由两个栅控X射线管构成立体X射线源,采用高灵敏度低惰性的单氧化铅摄象机作为电视摄象系统,通过对电子图象的处理,成功地获得了立体感强、射线剂量低的三维图象。本文在论述立体成象的基本原理之后,着重叙述三维图象立体深度分析法及获得三维图象的处理方法。本装置对于物理、生物医学的研究具有重要的应用价值。 关键词：     

飞秒激光光斑灰度与几何特征的相关性分析

飞秒激光烧蚀单晶硅的加工过程中,CCD相机采集的光斑图像中有效灰度区域与背景难以区分。为了解决这一问题,提出一种主成分分析与限制对比度自适应直方图均衡化相结合的方法,对光斑图像进行增强处理,再提出去趋势互相关分析法对光斑序列图像的灰度特征与几何特征进行长程相关性分析。结果表明,光斑序列图像的灰度特征与光斑纹理对比度、光斑面积具有较强的长程相关性,与纹理同质性表现出较强的反相关关系,可根据这3项与灰度特征较强的相关关系对后续微槽加工过程中的灰度特征进行预测。     

Line-scan CCD camera calibration in 2D coordinate measurement

We present a line-scan camera calibration method in a plane not perpendicular to but parallel to the optical axis, without requiring the camera motion or a complex calibration pattern. A random 2D reference coordinate system in the calibration plane can be used, images of a rod perpendicular to the calibration plane at known coordinates are captured by the camera, the relation between the given coordinates and the rod image centroid position are analyzed based on a reduced pinhole model and image processing, and then the camera parameters and distortion factors are all estimated. These distortion factors build a sample relation only between the image position in theory and in practice, and they do not change with object position. Two wide-angle line-scan cameras that are used in a 2D-coordinate measurement system are calibrated by this method; the application results illustrate the effectiveness and convenience of this method.     

基于机器视觉的移动工件抓取和装配的研究

针对工业生产线上某产品上下盖自动装配的问题,运用运动控制理论与机器视觉相结合,搭建了一套模拟工业生产线产品装配系统。首先利用工业相机对进入视场的工件进行单帧图像采集,获取图像数据;然后利用OpenCV对数字图像进行处理,包括中值滤波、阈值分割、孔洞填充、边缘提取来获取数字图像的特征;之后通过质心法结合矩形拟合计算出工件的质心坐标和偏转角度;最后引导六轴机械臂抓取产品的时候能根据图像处理结果进行纠偏和补偿。该系统采用平面棋盘格标定板对工业相机进行了标定,并且在线进行了验证,实验结果表明,工件抓取和装配成功率为100%,满足工业现场的装配精度要求。     

结构光测量技术中的投影仪标定算法

详细介绍了投影机模型,并提出一种简单、高精度的投影仪参数标定算法,该算法将投影仪当作一个逆向的相机,使用一块带有圆形标志点的平面标定板对投影仪进行标定.标定过程中,使用两组不同方向的光栅图像建立投影仪图像和相机图像的对应关系,从而得到投影仪标定所需的图像数据,将投影仪标定转化为成熟的相机标定,然后使用相机标定算法对投影仪进行高精度标定.实验结果表明,所提议的投影仪标定算法操作过程简单,标定精度可达0.312 pixel.     

遥感相机自动检焦技术研究

将基于图像处理的自动检焦技术应用于线阵CCD推扫成像的空间遥感相机中。图像法检焦的关键在于对焦评价函数的选取。通常对焦评价函数是在摄影目标不变的情况下得出的,而推扫成像的线阵CCD相机在任意时刻所拍摄的景物都是不同的,这就给对焦评价函数的选取增加了难度。用功率谱的方法对任意景物在空间频域进行分析表明,功率谱对于自然景物具有一定的不变性。由此建立了基于功率谱的对焦评价函数,采用小波去噪与亮度归一化相结合的图像预处理技术有效地去除了图像噪声和亮度变化对对焦精度的影响。通过对功率谱评价函数进行加权处理,提高了对焦评价函数曲线的灵敏度。仿真实验表明了所构造的对焦评价函数是可行的。     

光纤几何参数的自动检测仪

叙述了光纤几何参数的自动测试方法,光纤断面通过显微光学系统成像,由CCD摄像头接收,并通过图像采集系统传输到计算机中,供进一步处理,介绍了测量原理及数学模型,采用了图像增强,图像分割等处理技术,消除图像噪声,从光纤断面图像中提取有效信息,采用不同的算法,精确计算了光纤几何参数,编制了实用化软件,提供了实测结果及二三维图示,根据上述原理与技术研制的仪器,操作简便,测量精度高。     

基于ARM的视觉导航AGV图像处理方法研究

为了实现更加简单高效的标识线图像的检测与处理,提出了一种优化的基于ARM的视觉导航AGV标识线图像处理方法。首先对采集到的图像进行灰度化处理并使用Otsu算法对图像进行阈值分割;然后采用优化的中值滤波算法进行图像滤波并使用高效的边缘提取策略获取路径边缘特征;最后采用角度判断的方法剔除错误点并使用最小二乘法拟合成路径的中心线。实验结果表明,该方法有较高的准确率和较好的实时性,可以满足工业生产中的实际需求,适用于基于嵌入式系统开发的视觉导航AGV。     

船载摄像系统的一种电子稳像算法

提出了一种新的船载摄像系统的电子稳像算法———水天线稳像算法。算法的模型是基于船载摄像机运动和视频图像运动关系建立的。介绍了水天线的特点以及水天线稳像算法的实现,并利用水天线稳像算法对船载摄像系统获取的视频图像序列进行了稳像处理。实验结果表明,该算法具有稳像精度高、实时处理能力强的优点,实际应用效果较好。     

Phase-coded aperture for optical imaging

For the optical spectrum region, we describe a novel phase-coded aperture imaging system that can be used in a computational imaging camera. The optical design includes a phase-only screen followed by a detector array. A specific diffraction pattern forms at the detector array when the wavefront from a point source object passes through the phase screen. Since diffraction effects cannot be ignored in the optical regime, an iterative phase retrieval method is used to calculate the phase coded screen. Correlation type processing can be applied for the image recovery. Computer simulation results are presented to illustrate the excellent imaging performance of this camera.     

A new method to accelerate depth extraction for aperture-coded camera

Depth extraction, or the retrieval of three-dimensional information of the captured scene from camera, is an important problem in computer vision and image processing. The aperture-coded camera has certain advantages in depth extraction. However, such calculation will cost huge time as it contains weighted iterative deconvolution. In order to solve the problem, this paper proposes an improved algorithm in which the image is firstly segmented and then the small image regions are sampled for deconvolution and depth judgment. Experimental results prove that the proposed method can greatly reduce time consumption and save computer memory. On this basis, by using the characteristics of aperture-coded camera obtaining image and depth, we propose a framework to handle the application of stitching the images of occluded scene, and then carry out experiments.     

The use of a consumer grade photo camera in optical-digital correlator for pattern recognition and input scene restoration

In this work an optical-digital correlator for pattern recognition and input scene restoration is described. Main features of the described correlator are portability and ability of multi-element input scenes processing. The correlator consists of a consumer grade digital photo camera with a diffractive optical element (DOE) inserted as a correlation filter. Correlation of an input scene with a reference image recorded on the DOE are provided optically and registered by the digital photo camera for further processing. Using obtained correlation signals and DOE’s point spread function (PSF), one can restore the image of the input scene from the image of correlation signals by digital deconvolution algorithms.The construction of the correlator based on the consumer grade digital photo camera is presented. The software procedure that is necessary for images linearization of correlation signals is described. Experimental results on optical correlation are compared with numerical simulation. The results of images restoration from conventionally and specially processed correlation signals are reported. Quantitative estimations of accuracy of correlation signals as well as restored images of the input scene are presented.     

An eye behavior measuring device for VR system

This work presents an eye-tracking and pupil size-measuring device that interfaces with a computer for applications useful in psychometry, ophthalmology, physiology and virtual reality (VR) systems. This system utilizes a change-coupled device (CCD) camera, appropriate lenses, PC with frame grabber and a DSP unit with various types of VR equipment, i.e., HMD, simulator or LCD projection device. The digital signal processing unit is used to calculate the average brightness and contrast of the VR video image. A CCD camera with various attachments can be mounted on various VR systems to capture the human eye image for testing. An image capture card and a personal computer are used to analyze the test image. From the eye digital image, the computer obtains data on the pupil size and a trace of the tested eye. A pattern recognition computer program and five measurement parameters are used to distinguish the position of the pupil, calculate the pupil location coordinate and analyze the physical conditions of the user. These data can be plotted against the average brightness and contrast of the VR video image in real time. This information is shown on the screen of a personal computer and used for cross-link analysis. This eye-tracking interface can determine the position of a subject's pupil and map that position into a display point on a computer screen. The pupil size and location data versus the average brightness and contrast of a VR video image are computed in real time.     

数码相机综合评测系统

由于光电传感器、数字图像处理、电子元器件等各领域技术的发展,数码相机的成像质量在过去的十年里有了长足的发展。加工成本的下降使光电成像系统在众多领域得到广泛使用,成像镜头和成像系统的成像性能测试和评价也受到广泛的关注。数码相机可以方便地输出计算机识别的数字图像,而数字图像可以用计算机在无人干预的条件下自动处理,这使得数码相机成像质量的客观评测成为可能。在相关标准基础上,研究了数码相机多个参数的客观评测方法与计算方法。在单个参数评测的基础上,用基于属性模型评价的方法综合多个参数,对所评测的数码相机做出一个综合的等级评价和评分。     

可见/近红外实时成像光谱仪控制系统设计

针对高光谱成像需求,设计了一套可见/近红外实时成像光谱仪.光谱仪基于声光可调谐滤波器(Acousto-Optic Tunable Filter,AOTF)分光器件进行设计,光谱带宽为1.3μm,其中可见光相机工作在400～1000 nm波段,近红外相机工作在1000～1700 nm波段.光谱仪控制系统以现场可编程门阵列...     

Compact vision using circular dynamic stereoscopy with a beam splitter

Circular dynamic stereoscopy (CDS) has special advantages for 3-D measurement as it uses a single CCD camera without cumbersome settings. In CDS, annular streaks are recorded, with their size inversely proportional to the depth/distance of the measuring point from the CCD camera. Therefore three-dimensional information can be measured automatically by image processing techniques. When the measuring points are relatively dense, streaks on the image plane overlap, making automatic processing difficult. To cope with this problem, one of the coupled mirrors is replaced by a beam splitter. The annular streaks and their corresponding center positions are then recorded on the same image as the displacement. The recording of the center positions helps in resolving the overlapping annular streaks.     

Influence of Non-Linear Image Processing on Spatial Frequency Response of Digital Still Cameras

The spatial frequency response (SFR) for a digital still camera is affected by non-linear image processing. We analyze the influence of image enhancement processing and gamma correction on SFR characteristics by varying the edge chart contrast. SFR expressions depending on the chart image contrast are proposed, as is a measurement method of resolving power based on the slanted edge.     

A two-dimensional vision system with optical ranging capability

This paper describes an optical three-dimensional (3D) camera developed by combining a two-dimensional intensity image and non-contact time of flight (TOP) range image. The camera system consists of an amplitude modulated light source, an image dissector tube, a phase measuring circuit, and a host PC for system control. A semiconductor diode laser light source or a white light source and Kerr cell is used to generate continuously high frequency modulated light for bulk illumination of the scene to be viewed. A compact, 25 mm diameter image dissector camera (Hamamatsu N2730 or R4193) is used as a receiver to detect the modulated light and generate both a two-dimensional intensity image and a range image. The range is obtained by measuring the phase between the received signal and the transmitted signal. With the large detection area and the random access property of the image dissector camera, it is easy to scan systematically and electronically the illuminated area, within the frame, to identify the required object. Three different modulated frequencies (between 10 MHz and 45 MHz) have been used to obtain a range accuracy of 4 mm, over a distance of 10 m, within a time period of 10 ms per pixel. A demonstration of the three-dimensional vision system has been given, having an update time of 1 s during which a high resolution intensity image (300 × 300 pixels) is produced together with a limited number (100) of range measurements obtained for important features.     

一种成像测量图像径向几何畸变的校正方法

通过对具有径向畸变的摄像机模型的分析,设计了一套求解图像径向几何畸变中心和畸变多项式系数的方案。首先,依据校正样板曲线的弯曲程度应用一元线性回归法和逐次逼近法求取光学图像的几何畸变中心,然后应用递推最小二乘法求解径向几何畸变的多项式系数,最后根据所得到的畸变中心和畸变多项式系数对图像进行校正得到满足要求的图像。仿真试验证明:该方法可以通过一次采集单幅图像对成像系统进行高精度标定,能够对成像测量系统的径向几何畸变进行一定精度的校正。实践证明:该方法通过图像处理的方法提高成像测量系统的精度,降低了系统的设计成本,可以作为成像测量系统中单独标定摄像机畸变参数的一种简单有效的方法。