机器视觉关键技术与应用实例分析

本文简要介绍了有关机器视觉概念、系统的组成,并介绍了与机器视觉相关的关键技术,如照明光源、镜头、摄像机、图像采集卡、图像处理卡、集成式视觉组件等,最后扼要介绍了在工业检测、农产品分选、机器人导航等多个领域的应用实例.     

An In-Camera Data Stream Processing System for Defect Detection in Web Inspection Tasks

One of the aims of industrial machine vision is to develop computer and electronic systems to replace human vision in quality control of industrial production. Traditionally these systems consist of a line scan camera, host computer, frame grabber and one or more dedicated processing boards. In this paper we discuss the development of a new integrated design environment, developed for real-time defect detection, that eliminates the need for an external frame grabber and other associated host computer peripheral systems. The processing board contains a reconfigurable field programmable gate array FPGA inside a DALSA CCD camera. The FPGA is directly connected to the video data-stream and outputs data to a low bandwidth output bus. The system is targeted for web inspection but has the potential for broader application areas. We describe and show test results of the in-camera prototype system board and discuss some of the algorithms currently simulated and implemented for web inspection applications.     

种子自动数粒仪

本文介绍一种利用机器视觉技术研究开发的种子自动数粒仪 ,该系统基于美国NI公司的软件开发平台LabView 7.1和图像处理软件包IMAQVISION及IMAQPCI -14 11图像采集卡进行软硬件的开发。系统在硬件结构上主要包括电磁震动工作台、摄像机及灯光、图像采集卡、PC机 ;在软件上主要包括图像采集模块、图象处理模块、图像分析模块。试验结果表明 ,该系统操作简单 ,效率高 ,并解决了其他数种仪器对种子大小有要求的弊端。     

基于CCD图像传感器的火焰温度场测量的研究

研究了比色测温法的原理,推出了计算高温物体温度场的计算公式,并运用图像处理技术得到了高温物体表面的温度分布。同时以酒精灯火焰作为研究对象,通过彩色CCD工业相机和图像采集卡设置图像的各种参数,将火焰的数字图像采集到计算机,在对图像进行预处理后计算出火焰图像的温度场,最终生成了相应的等温线。     

高帧频面阵CCD实时显示系统设计

为了能够在特殊环境下拍摄到最优的图像,需要实时地调整相机参数,这要求实时显示拍摄的图像。使用FPGA配合通用Camera Link采集卡,设计了一套通用性很强的高帧频面阵CCD实时显示系统,使用Verilog HDL语言编写CCD驱动程序,能够通过USB实时调整相机的工作参数,使相机工作在最佳状态,使用KAI340D CCD在205.6fps的帧频下测试,系统工作良好,满足了实验需求。     

机器视觉中的图像采集技术

文章介绍了图像采集系统的构成以及在机器视觉中的重要性，阐述了图像采集系统中关于摄像机、镜头、图像采集卡和光源等方面的诸多实用技术，论述了设计图像采集系统时要注意的问题和原则。     

基于LabVIEW的SMT焊点质量信息视觉检测系统

根据SMT焊点质量信息检测的焊点形态理论,通过对SMT焊点图像处理分析,设计并实现了由LabVIEW工作平台、CCD摄像头、图像采集、系统标定、图像处理、三维重建及PC机等组成的SMT片式元器件焊点质量信息计算机视觉检测系统,有效地完成对SMT片式元器件焊点质量信息的检测任务,具有较强的扩展性。     

Fusing force and vision feedback for manipulating deformable objects

This article describes a framework that fuses vision and force feedback for the control of highly deformable objects. Deformable active contours, or snakes, are used to visually observe changes in object shape over time. Finite‐element models of object deformations are used with force feedback to predict expected visually observed deformations. Our approach improves the performance of large, complex deformable contour tracking over traditional computer vision tracking techniques. This same approach of combining deformable active contours with finite‐element material models is modified so that a vision sensor, i.e., a charge‐coupled device (CCD) camera, can be used as a force sensor. By visually tracking changes in contours on the object, material deflections can be transformed into applied stress estimates through finite element modeling. Therefore, internal object stresses due to object manipulation can be visually observed and controlled, thus creating a framework for deformable object manipulation. A pinhole camera model is used to accomplish vision and force sensor feedback assimilation from these two sensing modalities during manipulation. © 2001 John Wiley & Sons, Inc.     

一种基于斜率的摄像机畸变校正方法

普通 CCD摄像机在成像时都存在畸变成像误差 ,在机器人视觉检测及自动装配中 ,有效地进行误差校正对准确确定物体的位置具有重要的意义 .本文采用带有一阶径向畸变的小孔摄像机模型 ,提出一种基于线段斜率的方法 ,对摄像机镜头的径向畸变进行校正 ,不必标定太多的摄像机的外参数 ,方法简洁 ,适合于视觉系统中对摄像机畸变的实时校正 ,或对摄像机捕获的图像进行几何校正 .实验表明 ,具有很强的鲁棒性和较高的校正精度     

基于计算机视觉的齿条测量方法研究

提出一种基于计算机视觉的齿条测量方法。建立一套计算机视觉的测量系统,系统把CCD摄像机安装于光栅反馈式精密导轨上,精密导轨带动CCD摄像头移动对齿条各处进行图像采集,通过对采集图像的处理,实现全齿的测量,获得齿条的基本参数如齿距p、齿厚s等数据。实验对指示表卡尺齿条进行测量,并与东京精密S1910DX3轮廓度仪的测量结果对比,结果表明,此方法的测量精度能满足该类齿条测量的要求。该测量方法简单实用,有效提高了卡尺齿条的测量效率,为卡尺齿条的在线检测提供技术保障。     

基于Delphi的V系列图像采集卡开发应用

分析了常见的图像采集系统,以微视V系列图像采集卡及CCD传感器为核心,构成了一种实用的图像采集系统.对图像采集卡所提供函数进行了详细分析,并在Delphi环境下对其进行了二次开发.给出了在可视化编程环境下进行图像采集卡二次开发的方法和相应的应用实例.     

基于单视频图像序列的人体三维姿态重建

提出了至少存在一个深度值已知点的约束条件下,基于单视频图像序列重建人体三维姿态的方法.利用已知间距的平面点阵来标定获得摄像机参数,在透视投影模型下,根据单视频图像序列中人体关节点的二维数据,重建其三维信息.并将人体运动序列按照运动突变点划分为若干子序列,有效消除了二义性的干扰,较为精确的实现了人体三维姿态的重建.给出了该方法的实验过程及计算结果,验证了该算法的可行性和精度.     

Navigation system including associative memory

A new adaptive linear robot control system for a robot work cell that can visually track and intercept stationary and moving objects undergoing arbitrary motion anywhere along its predicted trajectory within the robot's workspace is presented in this paper. The proposed system was designed by integrating a stationary monocular CCD camera with off-the-shelf frame grabber and an industrial robot operation into a single application on the MATLAB platform. A combination of the model based object recognition technique and a learning vector quantization network is used for classifying stationary objects without overlapping. The optical flow technique and the MADALINE network are used for determining the target trajectory and generating the predicted robot trajectory based on visual servoing, respectively. The necessity of determining a model of the robot, camera, all the stationary and moving objects, and environment is eliminated. The location and image features of these objects need not be preprogrammed, marked and known before, and any change in a task is possible without changing the robot program. After the learning process on the robot, it is shown that the KUKA robot is capable of tracking and intercepting both stationary and moving objects at an optimal rendezvous point on the conveyor accurately in real-time.     

Three-dimensional model acquisition for medical robotics-assisted burn debridement system

This paper discusses the principles for the acquisition of a three-dimensional (3-D) computational model of the treatment area of a burn victim for a vision-servo-guided robot which ablates the victim's burned skin tissue by delivering a high-energy laser light to the burned tissue. The medical robotics assistant system consists of: a robot whose end effector is equipped with a laser head, whence the laser beam emanates, and a vision system which is used to acquire the 3-D coordinates of some points on the body surface; 3-D surface modeling routines for generating the surface model of the treatment area; and control and interface hardware and software for control and integration of all the system components. Discussion of the vision and surface modeling component of the medical robotics assistant system is the focus of this paper. The robot-assisted treatment process has two phases: an initial survey phase during which a model of the treatment area on the skin is built and used to plan an appropriate trajectory for the robot in the subsequent phase—the treatment phase, during which the laser surgery is performed. During the survey phase, the vision system employs a camera to acquire points on the surface of the patient's body by using the camera to capture the contour traced by a plane of light generated by a low power laser, distinct from the treatment laser. The camera's image is then processed. Selected points on the camera's two-dimensional image frame are used as input to a process that generates 3-D body surface points as the intersection point of the plane of light and the line of sight between the camera's image point and the body surface point. The acquired body surface points are then used to generate a computational model of the treatment area using the non-uniform rational B-splines (NURBS) surface modeling technique. The constructed NURBS surface model is used to generate a treatment plan for the execution of the treatment phase. The robot plan for treatment is discussed in another paper. The prototype of the entire burn treatment system is at an advanced stage of development and tests of the engineering principles on inanimate objects, discussed herein, are being conducted.     

Analog circuit for motion detection using a CCD camera based on a biological vision system and its application to mobile robots

We have proposed an analog motion detection circuit based on a biological vision system. A charge coupled device (CCD) camera was used as the input in order to obtain an input image. By using the CCD camera, it is possible to detect the movement of an object as a high-resolution image. Because the unit motion detection circuit is constructed with eight metal oxide semiconductor (MOS) transistors and one capacitor, the structure of the unit circuit is simple. The test circuit was constructed on a circuit board using discrete MOS transistors. The results from the test circuit showed that it can detect the direction of motion. The test circuit was connected to a microcomputer in a mobile robot. It was clear from the results that the motion detection circuit can control a mobile robot.     

基于数字CCD相机的高速图像采集系统

介绍了一种基于线阵CCD相机的高速数据采集的方法和系统,该系统采用双CCD相机进行布站并对过靶物体进行拍摄,通过图像采集卡实现计算机对CCD相机的控制,并且完成数据的采集和存储,能够成功运用到高速运动物体的空间位置和速度检测方面,经试验,其实时性和高精度性能使其很好地应用到靶场的立靶精度试验中,极大地提高了靶场试验效果。     

Hovering control of model helicopter by vision

In this paper, we introduce an autonomous flying model helicopter with a vision control system. A feature of the helicopter is that autonomous hovering is realized by a vision control system. Owing to this vision control system, the model helicopter is able to take off, land, and hover without any human assistance. The vision control sstem is composed of a CCD camera mounted on the helicopter and an image processor on the ground. We first introduce the configuration of the helicopter system, which has a vision sensor, a clinometer, and an azimuth sensor. To determine the 3-D position and posture of helicopter, a technique of image recognition using a monocular image is used. Finally, we give an experiment result which we obtained in a hovering test with the vision control system. This result shows the effectiveness of the vision control system in the model helicopter.     

基于LabVIEW的偏心桶口自动灌装系统开发

开发了基于LabVIEW及机器视觉技术的三坐标工作台灌装系统。系统使用CCD摄像机和图像采集卡采集图像。经图像标定、中值滤波、快速图像匹配等处理算法，获得偏心加注口的圆心坐标位置信息。以此控制三坐标工作台步进电机的运动。步进电机带动加注枪．实现偏心桶口的自动定位。实验证明，该系统运行可靠，算法高效、稳定，有较高的实用价值。     

一种步进电机控制面阵CCD摄像机获取大视域目标图像的方法

文章提出了一种利用步进电机控制面阵CCD摄像机获取大视域目标图像的方法，该方法采用上下位机串行通信进行同步，下位单片机控制步进电机移动机械装置，上位PC机控制装置上的面阵CCD进行单帧图像连续采集。整个大视域目标的图像像素数据由每帧图像正中间数行的像素数据逐步填充而成，实现了大视域目标图像的自然无缝获取。实践证明，该方法获取的图像效果非常好，具有较强的实用性和推广价值。     

Visual Servoing Based on Structure From Controlled Motion or on Robust Statistics

This paper focuses on the way to achieve accurate visual servoing tasks when the shape of the object being observed as well as the desired image are unknown. More precisely, we want to control the camera orientation with respect to the tangent plane at a certain object point corresponding to the center of a region of interest. We also want to observe this point at the principal point to fulfil a fixation task. A 3-D reconstruction phase must, therefore, be performed during the camera motion. Our approach is then close to the structure-from-motion problem. The reconstruction phase is based on the measurement of the 2-D motion in a region of interest and on the measurement of the camera velocity. Since the 2-D motion depends on the shape of the objects being observed, we introduce a unified motion model to cope both with planar and nonplanar objects. However, since this model is only an approximation, we propose two approaches to enlarge its domain of validity. The first is based on active vision, coupled with a 3-D reconstruction based on a continuous approach, and the second is based on statistical techniques of robust estimation, coupled with a 3-D reconstruction based on a discrete approach. Theoretical and experimental results compare both approaches.