李天华,吴增昊,廉宪坤,侯加林,施国英,王奇.基于定向摄像头的大拱棚运输车视觉导航研究[J].农业机械学报,2018,49(s1):8-13.
LI Tianhua,WU Zenghao,LIAN Xiankun,HOU Jialin,SHI Guoying,WANG Qi.Navigation Line Detection for Greenhouse Carrier Vehicle Based on Fixed Direction Camera[J].Transactions of the Chinese Society for Agricultural Machinery,2018,49(s1):8-13.
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基于定向摄像头的大拱棚运输车视觉导航研究   [下载全文]
Navigation Line Detection for Greenhouse Carrier Vehicle Based on Fixed Direction Camera   [Download Pdf][in English]
投稿时间:2018-07-02  
DOI:10.6041/j.issn.1000-1298.2018.S0.002
中文关键词:  视觉导航  色度法  路径检测  运动学仿真  摄像头云台
基金项目:国家特色蔬菜产业技术体系项目(CARS24D01)、山东省现代农业产业技术体系蔬菜创新团队项目(SDAIT0202211)和山东省农业重大应用技术创新项目(鲁财农指(2015)16号)
作者单位
李天华 山东农业大学 
吴增昊 山东农业大学 
廉宪坤 山东农业大学 
侯加林 山东农业大学 
施国英 山东农业大学 
王奇 山东农业大学 
中文摘要:针对大拱棚中运输车导航问题,提出了一种适用性更高的导航方法。为了规避叶间空隙对Hough直线变换精度造成的影响,使用道路尽头横向中心点作为导航信息标定点,搭建摄像头云台使得摄像头视轴始终与道路平行。使用色度法对作物与道路进行分割处理,通过面积筛选所得的轮廓点集,能够准确计算出道路尽头的横向中心点像素坐标,从而得到运输车的位姿信息。通过运动学建模对运输车进行了轨迹仿真,得到了运输车不同速度下对识别误差的动态响应。基于Raspberry Pi平台搭建了导航信息提取装置,在不同道路长度的拱棚中对比了本文方法与Hough变换法的识别精度,并使用不同类型摄像头进行了静态导航信息提取实验,同时在不同速度进行了运输车的直线行驶实验。静态实验表明,相比于传统Hough变换,该导航方法能够显著提高识别精度,使用长焦摄像头比普通摄像头识别精度平均提高了25.7%,导航线平均识别偏差为2.4cm,检测速率为240ms/f,具有较高的精度和实时性。行驶实验表明,该导航方法在不同速度下均能保证较小的稳态误差,能够满足生产要求。
LI Tianhua  WU Zenghao  LIAN Xiankun  HOU Jialin  SHI Guoying  WANG Qi
Shandong Agricultural University,Shandong Agricultural University,Shandong Agricultural University,Shandong Agricultural University,Shandong Agricultural University and Shandong Agricultural University
Key Words:vision navigation  hue  corridor detection  kinematic simulation  pan-tilt camera
Abstract:To solve the key prerequisite of greenhouse carrier vehicle navigation, a new navigation method was proposed based on fixed direction camera. A pan-tilt camera was constructed to collimate the vision line to corridor’s center line with geomagnetic sensor and digital servo. The angle error was detected by geomagnetic sensor and the error was compensated by servo. The drawback of Hough transform was avoided by using new method of picture processing. The vision system ran in Raspberry Pi based on OpenCV in Linux. It distinguished corridor and crop by value of hue instead of Excess—Green method and the end point of corridor was got by area of screening. By using the Ackerman principle, the vehicle’s position and attitude angle can be received. The dynamic response was got by modeling the equation of vehicle and simulating the movement of vehicle at different vehicle speeds. The experiment was done in real greenhouse which was divided into two parts, including the static experiment and dynamic experiment. The error of navigation information was obtained by processing the picture in fixed platform and a control experiment with Hough transform. The vehicle can drive automatically at different speeds in greenhouse. The results showed that the average time cost of this method was less than 240ms/f, the average detection error of the navigation line was 2.4cm, and the long-focus camera can reduce the error by 25.7%, which indicated that the method was available to get navigation line with appropriate accuracy and instantaneity.

Transactions of the Chinese Society for Agriculture Machinery (CSAM), in charged of China Association for Science and Technology (CAST), sponsored by CSAM and Chinese Academy of Agricultural Mechanization Science(CAAMS), started publication in 1957. It is the earliest interdisciplinary journal in Chinese which combines agricultural and engineering. It always closely grasps the development direction of agriculture engineering disciplines and the published papers represent the highest academic level of agriculture engineering in China. Currently, nearly 8,000 papers have been already published. There are around 3,000 papers contributed to the journal each year, but only around 600 of them will be accepted. Transactions of CSAM focuses on a wide range of agricultural machinery, irrigation, electronics, robotics, agro-products engineering, biological energy, agricultural structures and environment and more. Subjects in Transactions of the CSAM have been embodied by many internationally well-known index systems, such as: EI Compendex, CA, CSA, etc.

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