一种基于数字图像的空间测距算法及仪器研发
Instrument Development and Distance Measurement Algorithm Based on Digital Image
作者：樊庆文(四川大学 机械工程学院, 四川 成都 610065)；李海博(四川大学 机械工程学院, 四川 成都 610065)；裴宏亮(四川大学 机械工程学院, 四川 成都 610065)；王可(四川大学 机械工程学院, 四川 成都 610065)；蒋汶莙(四川大学 空天科学与工程学院, 四川 成都 610065)；赵志键(四川大学 机械工程学院, 四川 成都 610065)
Author：FAN Qingwen(School of Mechanical Eng., Sichuan Univ., Chengdu 610065, China)；LI Haibo(School of Mechanical Eng., Sichuan Univ., Chengdu 610065, China)；PEI Hongliang(School of Mechanical Eng., Sichuan Univ., Chengdu 610065, China)；WANG Ke(School of Mechanical Eng., Sichuan Univ., Chengdu 610065, China)；JIANG Wenjun(School of Aeronautics Sci. and Eng., Sichuan Univ., Chengdu 610065, China)；ZHAO Zhijian(School of Mechanical Eng., Sichuan Univ., Chengdu 610065, China)
收稿日期：2019-06-27 年卷（期）页码：2020,52(3):201-205
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：数字图像处理;机器视觉;空间测距;仪器设计
Key words：digital image processing;machine vision;distance measurement;instrument design
基金项目：四川省科技厅项目（19ZDYF1402）；四川大学火花库项目（2018SCUH0041）
中文摘要
基于数字图像的空间测距技术是非接触测量，其中汇聚式双目视觉系统具有测量视野大、对相机空间布局没有具体要求的特点，是目前基于数字图像的空间测距技术的研究热点之一。根据相机小孔成像原理，利用双目相机采集被测物在空间坐标系的平面图像信息（像素坐标），标定相机内外部参数以及相机外部参数旋转矩阵，平移向量，确定像素坐标系、图像坐标系、相机坐标系和世界坐标系之间的关系，构建测量对象平面图像像素坐标与世界坐标系中的坐标值之间的关系，建立基于数字图像的空间测距数学模型，通过平面图像上的像素坐标计算被测物两点之间的空间距离。按照便携式、低功耗、兼容性的原则，以RK3288为核心处理器，选用IMX–179作为图像传感器，基于Linux系统，研制基于数字图像的空间测距仪器，设计仪器的图像采集、数据传输、数据交换、数据处理模块，具有实时性好、测量效率高、系统结构简单、成本低等优点。实验证明，基于数字图像的空间测距仪器对10 cm的空间距离，在被测物位于相机前50～100 cm处的测量误差小于1% 。基于该算法的测量仪器在机器人视觉、非接触工程测量、智能制造等领域具有广泛的使用价值。
英文摘要
Distance measurement based on digital image is non-contact measurement. Among them, the convergent binocular vision system has a large measurement field and has no specific requirements for the camera’s spatial layout. It is one of the current research hotspots of distance measurement based on digital image technology. The mathematical model of distance measurement based on digital image is established according to the principles of camera pinhole imaging. A binocular camera is used to acquire planar image information (pixel coordinates) of a measured object in the space coordinate system, and these information are then used to calibrate the internal parameters and external parameters rotation matrix , translation vector . A methodology is presented to determine the relationship among the pixel coordinate system, the image coordinate system, the camera coordinate system and the world coordinate system as well as calculate the spatial distance between two points of a measured object by using their pixel coordinates on the planar image. A distance measurement instrument was developed based on digital images with the goal of optimized portability, power consumption and compatibility. the RK3288 is used as the core processor, and IMX-179 is selected as the image sensor, the Linux system is selected as developed system.This paper discusses the approaches to image acquisition, data transmission, data exchange, and data processing modules of the instrument. The instrument of distance measurement algorithm based on digital image has the advantages of good real-time performance, high measurement efficiency, simple system structure, and low cost. Experiments showed that the distance measurement instrument show digital images has a measurement error of less than 1% at a distance of 10 cm when the object is located at 50 cm to 100 cm in front of the camera. The measurement instrument based on this algorithm has a wide range of applications in robot vision, non-contact engineering measurement, intelligent manufacturing and other fields.
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