新型胶片影像判读仪的应用研究

针对狭缝摄影胶片参数测量和处理的自动化低,人为因素多,提出一种新型胶片影像判读仪。通过将光源照射到待扫描的材料上完成图像的获取,光源照射到CCD上实现光电转换。对胶片图像进行数字化处理,利用软件进行图像处理。结果表明,应用该判读仪实现了大幅面（830 mm190 mm）彩色胶片图像输入。平面结构和精密的传动系统保证了测量要求的全幅面小于0.1 mm的精度,提高了胶片判读的自动化程度和数据的精确测量及处理。     

应用时域相位解包方法的三维形貌测量系统

设计一套基于时域相位解包方法的三维形貌测量系统 ,克服了传统解包方法中的误差传播效应 ,可以应用于复杂物体表面及复杂环境下的三维形貌测量。由计算机生成光栅并通过液晶投影仪投射到待测物体表面 ,用CCD摄像机采集图像并通过图像采集卡存贮到计算机中进行处理 ,实现了测量的自动化 ,完成一次高精度的测量仅需几秒钟时间。用两个特殊的人头像完成的实验证明了系统的优越性     

基于三线结构光的大型圆柱工件直径测量系统

针对工业上一些无法正对待测端面安装相机的直径测量场景,设计了一种由3个激光投线器、1个成像透镜及1个面阵CMOS相机组成的圆柱工件直径测量系统,放置于地面上倾斜投影并成像。搭建了测量系统,从图像中获得亚像素端点坐标,代入标定方程解算世界坐标,并通过几何模型计算待测直径。实验结果表明,该系统能在设计待测值附近准确测量工件的端面直径,测量精度在±0.1 mm以内,满足工业测量高精度要求。     

基于蓝光扫描仪的高光面小圆角结构测量方法

对于高光表面及小圆角结构工件，传统的光学测量方法以及设备难以满足工程要求，基于蓝光扫描仪，提出一种球心偏置测量方法。在待测工件表面附着经220目砂粒喷砂处理的钢球，利用蓝光扫描仪对钢球进行快速扫描并拟合出扫描点云的球心点，沿待测工件表面法矢方向偏置钢球半径可得到工件表面实测点。利用该方法对标准圆棒进行测量，拟合直径差值为0.000 2 mm，测量精度在0.03 mm以内，验证了该方法原理的可行性。以进排气边圆角R < 0.1 mm的抛光叶片某条截面线为例，测量精度在0.03 mm以内。该方法不受待测工件表面材质影响，对于高反光表面以及具有微小结构特征工件的测量具有重要意义。     

THE MEASUREING AND PROCESSING OF STREAK CAMERA

狭缝摄影胶片图象运动参量测量和处理采用了胶片扫描仪对狭缝摄影胶片图象进行数字化,利用软件进行图象处理.文章介绍了对胶片扫描仪进行检验和标定方法;对由于狭缝摄影机的胶片速度和目标的实际影象速度不一致产生的畸变进行了分析和修正,实现了数据的精确测量和处理.     

狭缝摄影胶片图象运动参量测量和处理

狭缝摄影胶片图象运动参量测量和处理采用了胶片扫描仪对狭缝摄影胶片图象进行数字化,利用软件进行图象处理.文章介绍了对胶片扫描仪进行检验和标定方法;对由于狭缝摄影机的胶片速度和目标的实际影象速度不一致产生的畸变进行了分析和修正,实现了数据的精确测量和处理.     

大视场多CCD拼接相机标定方法研究

介绍了一种多CCD拼接弹道相机的标定方法和步骤,以及标定系统的原理及组成。对相机的光学畸变和大视场拼接物像几何投影关系进行了分析,建立了相机数学模型,并采用最小二乘多元回归分析方法,通过测量相机的内方位元素计算畸变系数,确定了最佳条件下相机数学模型中的各个参数。实验表明利用该方法标定出相机精度方位角测角误差小于10″,高低角测角误差小于15″。     

单目显微视觉测头动态测量技术的研究

为了解决现有坐标测量机中的单目显微视觉测头视场小和景深小的缺点,提出了显微视觉测头的动态测量方法。建立了运动模糊图像的复原模型以及序列图像的全景组合模型,并提出了测量系统的自标定方法,标定重复性精度优于0.5nm。实验证明:该系统在以6mm/s的速度扫描测量时,测量重复性精度可达到5μm。     

基于机器视觉的高精度测量与装配系统设计

在对某些精密产品实现自动化生产过程中,存在难以对装配该产品所需的多种装配小零件进行高精度自动测量与装配的问题。针对该问题,搭建了基于机器视觉技术的自动化测量与装配系统。基于Halcon图像处理软件平台,对零件图像进行了中值滤波、图像增强等预处理;采用了Canny算法对零件求取像素精度的边缘,并运用椭圆曲线拟合法获取了亚像素精度边缘;建立了两种相机镜头畸变模型,采用径向排列约束(RAC)标定法与张正友标定法对相机进行了标定,并对标定精度进行了对比;实验结果表明：本系统的装配同轴度精度能达到0.05mm,零件尺寸测量标准差低于3.8μm,满足工业需求,可以解决工业实际问题。     

像增强器的荧光屏亮度均匀性测试的校正法研究

像增强器荧光屏亮度均匀性参数是判断其性能好坏的一个重要技术指标。设计了一种测试系统来测试它的亮度均匀性参数。该系统利用标定过的具有均匀亮度的荧光屏(裸屏),以标准像增强器的图像作为标准来校正面源电子枪。由于校正后的面源电子枪仍然存在误差,所以具有均匀亮度的荧光屏(裸屏)的图像不可能是完全均匀的,呈现边缘暗中间亮。分析其图像的亮度曲线,建立校正函数,改变校正函数中的调节系数,直到计算机上显示出图像均匀为止,这时可得出系数确定的校正函数。首先利用校正后的电子枪轰击待测荧光屏,采集其图像,以确定的校正函数对其进行修正,然后观察由计算机显示出的图像是否均匀,从而判断待测荧光屏的均匀性。     

Innovative calibration technique for fringe projection based 3D scanner

A new approach to 3D scanners calibration, based on Fourier Transform Profilometry method, is proposed and verified by experiments. Commonly used calibration techniques require that a calibration plane is placed in different and known positions in the scanner measuring volume; an optimization procedure iteratively change the value of some calibration parameters in order to minimize the discrepancy between the height distributions of the measured planes and the reference ones. The main limit of this type of calibration techniques is the necessity to guarantee a high accuracy in the placement of the planes used as calibration references. The innovation of the method proposed in this paper is the complete removal of any device for the accurate plane placement by assigning the task of the plane positions estimation to the camera, which is part of the scanner. The well known camera calibration algorithm proposed by Zhang permits at the same time to calibrate the camera and to estimate the positions and orientations of the plane used for the calibration itself. The knowledge of the plane position allows to use them as a reference of the scanner calibration. The obtained results show that this method provides accuracy values for the scanner parameters estimation comparable with other calibration techniques, but the advantage is that no particular device is needed.     

Accurate calibration for a camera–projector measurement system based on structured light projection

The accurate calibration for a camera–projector measurement system based on structured light projection is important to the system measurement accuracy. This study proposes an improved systematic calibration method focusing on three key factors: calibration model, calibration artifact and calibration procedures. The calibration model better describes the camera and projector imaging process by considering higher to fourth order radial and tangential lens distortion. The calibration artifact provides a sufficient number of accurate 3D reference points uniformly distributed in a common world coordinate system. And the calibration procedures calibrate the camera and projector simultaneously based on the same reference points to eliminate the influences of the camera calibration error on the projector calibration. The experiments demonstrate that our calibration method can improve the measurement accuracy by 47%.     

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.     

低伸弹道狭缝联动摄影系统标定技术的研究

在低伸弹道测量中，为了对弹丸的飞行资态，章动角，章动周期，弹丸飞行速度和旋转速度等进行精确，可靠的测量，需要对所采用的狭逢联动摄影系统进行精密的标定。本文在比较以往所用方法的基础上，提出了一种新的标定方法，实现了系统的精密，快速标定。     

A fast and accurate calibration method for the structured light system based on trapezoidal phase-shifting pattern

Calibration plays an important part in the structured light system. It used to be regarded as time-consuming, expensive and hard to implement. In this paper, we introduce a novel and fast method to calibrate the structured light system by using the camera to control the projector to “capture” images. Firstly, we projected just six trapezoidal grayscale pattern to establish the corresponding pixel between the camera and the projector, then we converted the camera image to its corresponding projector image. Thus the structured light system can be easy controlled by the camera calibration. Experiments showed that the present calibration method is fast, easy and accurate.     

面向大视场视觉测量的摄像机标定技术

提出了一种面向大视场高精度视觉测量的摄像机标定新方法,该方法采用亮度自适应的单个红外发光二极管(IR-LED)作为目标靶点,将该靶点固定在三坐标测量机的测头上,并依次精确移动至预先设定的空间位置,每次靶点到达设定的空间位置时,摄像机对靶点进行图像采集。利用三坐标测量机的精确位移,在三维空间构成一个虚拟立体靶标。针对虚拟立体靶标在大视场摄像机标定中只能覆盖一小部分标定空间的问题,通过自由移动摄像机在多个方位对虚拟立体靶标进行拍摄,使得多个虚拟立体靶标分布于整个标定空间。摄像机在每个方位对虚拟立体靶标的拍摄都标定出一组摄像机的内、外参数,然后以摄像机内参数和摄像机在各个方位下拍摄的虚拟立体靶标在摄像机坐标系下的位置及姿态参数为优化变量,建立以所有三维靶点位置重投影误差平方和为最小的目标函数,采用非线性优化方法求解摄像机标定参数的最优解。该方法较好地解决了大视场视觉测量中大尺寸靶标加工困难、摄像机标定精度难以保证的问题。仿真和实际标定实验均证明此方法可以有效提高大视场摄像机的标定精度。     

Flexible sheet with radiophotoluminescence glass beads for remotely monitoring high beta-surface-contamination

A flexible sheet was made with radiophotoluminescence (RPL) glass beads on an experimental basis for visualization of high beta-surface-contamination. A simple RPL observation system for remote contamination monitoring was constructed with a homemade UV floodlight and a commercially available digital camera with supplementary optical lenses and filters. In preliminary experiments, RPL images were well observed with the digital camera of the present system. Their precise RPL intensity was determined after the correction of nonlinear response of the camera. It was expected from experiments that RPL images of beta-surface-contamination could be quantitatively evaluated through calibration, i.e., the conversion of camera images to dose data on the sheet-type glass dosimeter.     

放疗3D剂量验证系统中光场相机点扩散函数获取

基于闪烁光场成像的放疗新型3D剂量测量中,需利用点扩散函数将每一个二维平面的真实闪烁光数据从重叠图像中提取出来。利用刀口法,结合光场数字重聚焦以及聚焦测距法,实验获取光场相机不同重聚焦位置处的点扩散函数,并给出棋盘格标定板在参数α=0.6时的重聚焦面聚焦在α=0.7位置处的高斯离焦点扩散函数表达式,研究光场相机点扩散函数的规律,通过测量几个必要值便可由函数拟合得到所有点扩散函数,减少光学分层成像中因分层数量增加引起的标定工作量。将结果引入图像处理,通过反卷积运算可获得每一个二维重聚焦面的真实闪烁光数据,有助于3D剂量的实时精确测量。     

采用广角数码相机测量图像显示系统的几何畸变

准确地测量含有广角耦合物镜的图像显示系统的几何畸变是实现图像显示系统几何畸变数字校正的前提和关键。提出了一种以非量测广角数码相机为测量设备的几何畸变的测量方法，首先给出了广角数码相机镜头畸变的标定方法，确定了数码相机镜头畸变系数，然后讨论了基于广角数码相机和Photoshop软件进行图像显示系统几何畸变测量的测量方法，分析了影响测量精度的因素。最后，将本文的测量结果与基于点物成像原理，采用单轴转台和普通数码相机进行测量的测量结果进行了对比，二者吻合得较好。从测量结果看，本文给出的测量方法，其测量精度可以满足工程要求，简单、易行。