Research On On-line Monitoring System Of Grain Impurity And Broken Rate Of Rice And Wheat Based On Mask R-CNN

The rate of impurity and broken of grain are important performance indicator of the combine harvester when harvesting rice and wheat.Monitoring the impurity rate and broken rate of rice and wheat seeds during combine harvester field operation can help operators understand the working condition of the machine,quickly adjust the state of the combine harvester,and reduce the trash and breakage of rice and wheat produced by the combine harvester during operation.In response to the problems of slow sampling and high failure rate of the existing rice and wheat seed impurity rate and broken rate monitoring devices developed by the group,this paper developed a Mask R-CNN-based online monitoring system for rice and wheat seed impurity rate and broken rate.The system was deployed on a combine harvester to monitor the impurity rate and broken rate of grain when the combine harvester is harvesting,and the monitoring results are displayed for the driver’s reference,so that the driver can adjust the combine harvester operating parameters in time to reduce the trash and breakage in the harvested grain.The main research work of this paper is as follows.(1)The existing model for calculating the impurity rate and broken rate is improved to address the calculation errors.It is proposed to extract the number of intact grain kernels,the pixel area of brokengrain kernels and impurities from the images,and then establish the correspondence between these parameters and weight to calculate the impurity rate and broken rate,which has significantly improved the accuracy than the existing calculation methods.(2)The rice and wheat image acquisition device was designed for the problem of difficult grain image sampling and harsh sampling environment of combine harvester.The image acquisition device mainly consists of grain infusion device,industrial camera,white light source,etc.The hardware was selected according to the research purpose and power requirements,etc.,it can collect high-quality grain images in complex situations.The online monitoring system for impurity rate and broken rate of rice and wheat was built.(3)For the characteristics of the grain images captured by the image acquisition device,a study was conducted on the rice and wheat image processing method based on the instance segmentation algorithm Mask R-CNN,with the addition of the branching algorithm for edge detection.The improved Mask R-CNN network algorithm has 98.43% recognition accuracy for intact wheat seeds,95.21% and94.03% segmentation accuracy for broken wheat seeds and wheat impurities;97.62%recognition accuracy for intact rice seeds,93.67% and 94.88% segmentation accuracy for broken rice seeds and rice impurities.(4)The software of on-line monitoring system for impurity-broken rate of rice and wheat grains was designed.The software of the monitoring system mainly includes image acquisition program,image processing program,impurity rate and broken rate calculation program,image display program and communication program.(5)In order to verify the feasibility and stability of the monitoring system,an online monitoring system based on Mask R-CNN for rice and wheat seed impurity-crushing rate was tested.The average relative errors of monitoring rice seed trash content and crushing rate were 5.77% and 6.34%,respectively;the average relative errors of monitoring wheat seed trash content and crushing rate were 6.18%and 7.28%,respectively.The online monitoring device was installed on the combine harvester for the rice and wheat field harvesting test,and the average relative errors of monitoring the seed trash rate and broken rate in the wheat field harvesting test were7.51% and 8.18%,respectively;the average relative errors of monitoring the seed trash rate and broken rate in the rice field harvesting test were 7.36% and 7.96%,respectively.The developed on-line monitoring system of impurity and broken rate of rice and wheat grains can help the driver obtain the impurity and broken of harvested rice and wheat grains in time,help the driver quickly adjust the operation parameters of the combine harvester,reduce the rice and wheat impurity and damage in the harvest process,and improve the harvest performance and quality of harvested rice and wheat of the combine harvester.