蒋郁,崔宏伟,区颖刚,马旭,齐龙,郑文汉.基于茎基部分区边缘拟合的稻株定位方法[J].农业机械学报,2017,48(6):23-31,49.
JIANG Yu,CUI Hongwei,OU Yinggang,MA Xu,QI Long,ZHENG Wenhan.Positioning Method of Rice Seedlings Based on Edge Fitting in Separated Region of Stem Base[J].Transactions of the Chinese Society for Agricultural Machinery,2017,48(6):23-31,49.
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基于茎基部分区边缘拟合的稻株定位方法   [下载全文]
Positioning Method of Rice Seedlings Based on Edge Fitting in Separated Region of Stem Base   [Download Pdf][in English]
投稿时间:2017-01-10  
DOI:10.6041/j.issn.1000-1298.2017.06.003
中文关键词:  水稻  机械除草  株间除草  定位  茎基部
基金项目:国家自然科学基金项目(51575195)、广东省自然科学基金项目(2015A030313402)、广东省科技计划重点项目(2014B020207003)、现代农业产业技术体系建设专项资金项目(CARS-01-33)、广东省科技计划项目(2014A020208112)和广州市珠江科技新星专项(2014J2200041)
作者单位
蒋郁 华南农业大学工程学院
华南农业大学现代教育技术中心 
崔宏伟 华南农业大学工程学院 
区颖刚 华南农业大学工程学院 
马旭 华南农业大学工程学院
南方粮油作物协同创新中心 
齐龙 华南农业大学工程学院
南方粮油作物协同创新中心 
郑文汉 华南农业大学工程学院 
中文摘要:准确地定位稻株是水稻株间除草机械作业的前提,提出了侧位俯拍的图像采集方式获取稻株茎基部图像,采用茎基部分区边缘拟合的方法定位稻株,解决了除草期内水稻冠层接连引起的定位不准确问题。首先分析稻株生长形态,探究侧位俯拍稻株茎基部的相机安装参数设定,以及影响成像质量的相关因素,提出了遮光条件下采集图像的方法,构建了具有遮光功能的图像采集系统;其次采用2G-R-B彩色图像灰度化、自动阈值、形态学操作等方法处理并分割稻株图像,检测茎基部边缘并分析其形态特征,并提出了分区边缘拟合定位方法:划分拟合区间为3个子区间,在子区间内进行边缘拟合,以拟合边缘线段中点坐标均值作为子区间茎基部中点,根据中点拟合茎基部中线,以中线中点作为定位的茎基部中心。最后进行了基于茎基部与冠层的稻株定位精度田间对比试验,结果显示:插秧后10~20d内,基于茎基部的稻株定位误差均在7.0mm以下,其中10d、15d、20d时的定位误差分别为6.9mm/6.8mm、5.9mm/5.8mm、6.3mm/6.5mm(有水条件/无水条件);基于冠层的稻株定位误差在8.0mm以上,其中插秧20d后,定位误差超过15mm以上。试验结果表明,所提出的基于茎基部分区边缘拟合的稻株定位方法,定位精度高,除草适用期长,可满足株间机械除草过程中对稻株精准定位的技术要求。
JIANG Yu  CUI Hongwei  OU Yinggang  MA Xu  QI Long  ZHENG Wenhan
College of Engineering, South China Agricultural University;Modern Educational Technology Center, South China Agricultural University,College of Engineering, South China Agricultural University,College of Engineering, South China Agricultural University,College of Engineering, South China Agricultural University;Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China,College of Engineering, South China Agricultural University;Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China and College of Engineering, South China Agricultural University
Key Words:rice seedlings  mechanical weeding  intra row weeding  positioning  stem base
Abstract:Positioning of rice seedlings is an important step of mechanical intra row weeding. Aiming to minimize the positioning errors based on canopy of rice, a system that could capture RGB images of rice stem base on the side view was built to position the rice seedlings according to edge fitting in separated region of the stem base. Firstly, relevant factors, including the morphology of rice seedlings, the installation parameters of camera on the side view and affecting image quality were analyzed, and a method of grabbing image under shading conditions was proposed, contributing to a system with shading device. The original RGB images were distinguished from soil by analyzing the excessive green (2G-R-B) rice seedlings index images. The Otsu algorithm method was employed to transform a gray image to a binary image, and then the binary images were smoothed by morphological operation to remove noise for subsequent analysis. After that the edges of stem base were extracted by the Canny operator, and the fitting region of edges was set up. A method was presented in fitting region based on edge fitting in non separated region of the stem base. However, the results showed that this positioning method was not accurate because of effect of unsmooth and unilateral sloping edges of stem base. Therefore, the fitting region was separated into three subintervals where the edges of stem base were fitted by the Hough transform. The center of rice seedlings was gained by the center coordinates of the mid line fitted by the mean of midpoint coordinates of fitting edges. The positioning experiments of rice seedlings in terms of stem base and the canopy were carried out respectively. The results of positioning based on stem base showed that the positioning errors were less than 7.0mm, and the positioning errors were 6.9mm, 5.9mm and 6.3mm under the condition of including water and 6.8mm, 5.8mm and 6.5mm under the anhydrous condition on the 10th, 15th and 20th day after transplanting, respectively. The results of positioning based on canopy showed that the positioning errors were above 8.0mm, and the positioning errors were 8.2mm, 11.3mm and 15.4mm under the condition of including water and 9.0mm, 10.7mm and 16.1mm under the anhydrous condition on the 10th, 15th and 20th day after transplanting, respectively. The results suggested that the innovative positioning method that based on edge fitting in separated region of the stem base of rice seedlings met the technical requirement of mechanical weeding in terms of high precision and long applicable period.

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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