基于CCD的空间光束投影夹角测量

针对空间光束定位的特殊性,常需要进行非接触光学测量,设计了一种基于电荷耦合器件（CCD）的空间光束投影夹角测量方法,采用多圆拟合算法进行光斑中心定位。通过测定两交叉光束在2个分别与CCD成像面保持水平及竖直垂直的投影面上的夹角,实现对空间光束的准确定位。实验测量结果表明,该测量系统具有较高的测量精度。     

会聚式相机获取的视差图像的梯形失真校正

为了消除会聚式相机所拍摄的视差图像中由于梯形失真引入的垂直视差,基于立体成像时同一深度的物点应具有同一水平视差且不存在垂直视差的原理,提出了在相机拍摄场景中的某一深度放置标定板并以中相机所拍摄的标定板图像作为参考视筹图像来校正其他待校正视筹图像的方法.以标定板特征点在待校正视差图像及参考视差图像中的坐标值建立待校正视差图像在校止前后的坐标映射关系,并通过图像采样得到校正后视差图像.实验结果表明,该方法有效地减小甚至消除了视差图像中的垂直视差,具有可行性,对提高立体显示效果具有指导意义.     

结构光双目测量系统标定方法

为了解决双目结构光测量系统参数不容易准确获取的问题,依据传统摄像机标定方法,结合结构光双目测量系统的特点,提出了CCD摄像机标定方法.通过对左右CCD摄像机采集得到的两幅标定模块的图像数据分析,按照"两步"标定法的思路,先得到平移向量R和旋转矩阵R等外部参数,再利用已知的空间距离求解到摄像机的成像模型需要标定的其他参数.实验数据表明,该方法可简便、准确地标定出CCD摄像机参数,方便了三维视觉测量工作,是一种有实用性的标定方法.     

基于光轴约束的机械臂运动学标定方法

为了提高机械臂的绝对定位精度,本文提出一种基于光轴虚拟约束的运动学参数标定方法。建立基于虚拟直线约束的运动学误差模型;本文在相机光轴的约束下,使用基于图像的视觉控制方法,使机械臂末端标定板的固定特征点依次到达光轴的多个位置;根据运动学模型计算特征点的对齐位置差,并使用迭代最小二乘法求解运动学参数误差。设计了Reinovo六自由度工业机械臂的运动学参数标定实验,对于随机产生的测试点,标定前的平均对齐误差为1. 50 mm,标定后降至0. 72 mm,机械臂末端的定位精度提高了52%,实验结果验证了该方法的有效性。     

椭圆拟合的圆环模板摄像机标定

结合平面模板和一维标定物摄像机标定方法的优点,提出了一种新的基于椭圆拟合的圆环模板摄像机标定方法．该方法设计了一种新的圆环模板,只需要3副模板图像即可标定摄像机; 通过引入椭圆拟合精确定位圆环模板特征点,利用非线性优化进一步提高了摄像机的标定精度．仿真实验结果表明,该方法精确度高、鲁棒性强,通过在真实图像上的实验,验证了该算法的性能．     

用于摄像机标定的图像特征点提取算法

如何快速准确地提取标定板图像的特征点坐标是摄像机标定中的关键问题之一.该文针对摄像机以特定的空间角度成像的标定问题,提出了一种用于摄像机标定的图像特征点提取算法.此算法对图像进行区域选取,并对区域图像进行大津阈值分割,击中击不中细化,象素统计等处理,得到特征点的坐标值.实验结果表明该方法可以快速有效地获取特征点的坐标,...     

数码相机标定模型研究

首先依据图像几何学,建立投影成像模型,找到标靶圆心在像平面的坐标.通过像坐标与标靶坐标的比较,论证了所建立模型的稳定性.其次建立双目定位模型,通过空间几何和矩阵变换得到两个数码相机相对位置的求解方法.     

柱面透视投影模型下的全景环形透镜畸变校正

根据全景环形透镜的成像机理特点,提出了用柱面透视投影模型来对图像畸变进行校正.在柱面投影模型中,空间直线的投影不再是直线,而是一个短轴不变的椭圆.首先建立含有畸变参数的全景环形透镜柱面校正模型,将空间直线点映射为柱面的椭圆上的点,然后使用投影长度和为零的条件,将环形像面上的点拟合为柱面上的最佳椭圆,求出变形校正参数,进而校正全景环形像.仿真和真实图像实验表明,环形图像的切向和径向畸变得到了校正,误差达到了亚像素级.     

机器视觉中空间圆透视投影特性研究

分析了三维圆与透视投影图像之间的几何关系,根据相似三角形比例原则和解析几何方法,描述了三维圆图像的数学特征,推导出了圆的图像椭圆曲线方程,确立了图像二次曲线中心偏移计算公式,图像曲线方程的几何意义清楚。     

光电法测试激光束散角研究

介绍了一种宽光谱高能脉冲激光束散角的测试方法.脉冲激光经过成像光学系统聚焦,在CCD像面上形成光斑图像,利用MATLAB图像处理软件对该光斑图像行分析处理,得到光斑直径值,从而计算求出激光束散角的值.给出了实验装置和工作原理以及在计算机中进行数据处理的方法.实验结果表明,采用该方法可以较为精确测量出微小角度高能脉冲激光束散角的值.     

基于DM6446齿轮尺寸参数图像测量算法设计

该文采用机器视觉方式实现齿轮尺寸参数的非接触式测量.算法首先采用摄像机标定算法,对采集的图像进行畸变矫正.并对该图像进行一系列图像处理,提取齿轮的轴心圆所对应的前景象素点作为样本点,并利用二维灰度矩边缘定位法,对样本点进行亚象素定位.利用最小二乘法拟合出齿轮的轴心圆、齿根圆及齿顶圆.最后,求出齿轮的尺寸参数.该文在TI公司推出的Davinci系列DSP处理器TMS320DM6446上实现提出的齿轮的尺寸参数测量算法.     

Study on the relative radiometric correction of CBERS satellite CCD image

China-Brazial Earth Resources Satellite (CBERS)-01 is the first remote sensing re- source satellite of data transfer type manufactured by China and Brazil, which is full of the wisdom and sweat from both countries’ aerospace communities and is regarded as a model of the cooperation between developing countries in high-tech area. CBERS-01 was launched in October of 1999 and went into normal operation after on-orbit test inMarch of 2000. This brought an end to the history that China coul…     

一种基于图像处理的余药检测处理方法

介绍了一种基于计算机数字图像处理的雷管自动生产线装药系统余药检测处理方法,将CCD摄像机拍摄的装药系统彩色图片通过HSV颜色模式转化并进行模式分类后,直接转化为二值图像,结合特定区域分析处理方法,经过腐蚀膨胀运算,以最小二乘原理拟圆的方法提取有效参数,计算余药量,以实现准确快捷实时检测余药药量的目的.     

Study on the relative radiometric correction of CBERS satellite CCD image

The main payload on CBERS-01/02 of China-Brazil Earth Resources Satellite (CBERS) is a push-broom CCD camera with moderate spatial and radiant resolution. Because at lab the data for calibration at satellite assembly stage were unable to be collected, and also because the onboard calibrator after launch was in a different state from imaging, the calibration of CCD image got a series of difficulties involved. In practice, two methods are used in the processing on the ground station: One is extracting calibration data by statistics from the image itself, and the other is the method of histogram match. It was proved that the latter can calibrate the image much better, because it can remove the effect of unstable response of the camera largely and also can overcome the nonlinearity of the camera basically by using Look-Up Table (LUT) calculated from histogram statistics of different temporal images. Considering the problems of CBERS-01, a lot of calibration tests were done before the launch of CBERS-02, in which a set of lab coefficients for relative calibration was formulated after the data collection by using integration-hemisphere in the stage of satellite assembly test. During the on-orbit test, it was found that the calibration result from such coefficients was not satisfying, especially there being response difference between 3 detector arrays, which was attributed to the unstable dark currents of the CCD camera. This paper comes up with a statistic method to remove such response difference. In this method the middle detector array was used as reference to find the response differences of adjacent similar features between these arrays and it was proved to have a broad adaptability.     

Water target based cross-calibration of CBERS-02 CCD camera with MODIS data

In order to make quantitative watercolor sensing with China-Brazil Earth Resources Satellite (CBERS-02) CCD camera, the MODIS data with higher accuracy is used to cross-calibrate the CCD camera over water targets. In homogeneous clear water area, two pairs of images obtained over the same area on the same day by the two sensors are selected. The top-of-atmosphere (TOA) radiances of the multispectral bands of CCD are calculated with the water and aerosol parameters from MODIS based on a water-atmosphere radiative transfer algorithm. The stripes in CCD image that caused by unequal response of the CCD array detectors are firstly removed before making the cross-calibration. The same part of CCD detectors is selected for the calibrations in the two images to eliminate the residual error of destriping and uniformity correction for the focus plane irradiance. It is shown that the calibration results from two different images are consistent. The error of this method is about 5%.     

Water target based cross-calibration of CBERS-02 CCD camera with MODIS data

The CBERS-02, the second satellite of China Brazil Earth Resources Satellite series, was launched on Oct. 21, 2002. Onboard the satellite, there are three major sensors, a CCD camera, a wide field imager and an infrared multispectral scanner (http://www. cresda.com). The purpose of this paper is to calibrate the CCD camera with a methodol- ogy of cross-calibration. The spatial resolution of the multispectal bands of CCD camera is 19.5 m, the swath is about 115 km. It is capable of side…     

CCD相机靶面倾斜误差修正应用研究

分析了光电经纬仪CCD相机靶面倾斜所带来的测量误差,解析了靶面倾斜时目标相对于光电经纬仪视轴的真实脱靶量和CCD靶面所读出的脱靶量之间的数学关系,给出了倾斜检测的方法及误差消除的数学公式,实践证明,本方法能较好地修正对CCD相机靶面倾斜对装备测量带来的影响,提高了测量精度.     

Non-Metric CCD Camera Calibration Algorithm in a Digital Photogrammetry System

Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.     

机器视觉中彩色伪随机编码投影系统及标定

为了研究基于三维场景单幅二维图像的不标定欧式重构理论,需要构造一个编码投影系统,并预标定出其相关参数,依据伪随机彩色编码的原理,代数射影几何中的交比不变性质,以及被视为逆向照相机投影系统的标定数学模型,提出了投影系统的标定步骤和方法．将一幅伪随机编码图案与投影系统相结合,构造了一种新的视觉投影系统．标定实验表明,由此系统将伪随机彩色编码图案投射到靶标空间,利用CCD照相机拍摄其图像,进行图像的特征点提取和数据处理后得到了投影系统的参数。     

光栅型结构光测量系统中CCD摄像机的标定

建立了CCD摄像机的畸变模型和实际成像模型,提出了一种利用计量块规标定CCD摄像机的新方法,并给出了详细的标定步骤。