基于机器视觉的玉米种粒定向定位摆放装置研制

为实现玉米定向、定位播种,基于图像处理技术研制了一种玉米种粒定向定位摆放装置。在介绍装置的组成和工作原理的基础上,设计了关键部件的结构,通过试验分析和理论计算,确定了关键部件的尺寸参数和安装方位,测试了导向定位管的定位精度,分析了凹型定位槽连续有效作业的条件,并结合作业精度要求,设计了控制方式并设置了控制参数。同时结合金博士郑单958种粒样本的特点,改进了合格种粒胚芽正反面和尖端朝向的图像检测算法。试验结果表明,胚芽正反面检测准确率为98%,尖端朝向检测偏差小于8°,凹槽定位准确率为97%,定位吸取准确率为94%,定位摆放准确率为99%,摆放后角度偏差不大于10°,满足设计要求。该研究可为实现种粒的定向包装以及后续的定向播种提供参考。

Development of corn seed directional positioning machine based on machine vision

Abstract: Directional seeding of corn seed can improve the light energy utilization of corn plants and the ventilated effect of field, which is of great significance to increase the corn yield per unit area. In order to realize directional seeding of corn seed, this study developed a kind of corn seed directional positioning machine based on image processing technology, and its main components included seed-metering device, conveying device, image acquisition and processing unit and directional positioning device. First, the compulsory clamp-type precision seed-metering device was chosen to complete seed feeding, and combined with the process of feeding seed when duckbilled seeding mouth was opened by roller, a guide-localization method was proposed for positioning process of seed onto conveyer belt. Based on this method, a kind of guide-localization tube was designed, and its structural dimension and installation position were determined through empirical analysis and theoretical calculation. And then the actual position distribution of corn seeds fed onto conveyer belt was acquired by the experiment. Also, locating notch of concave shape was designed to position seed by a mechanical way, and through speed and displacement analysis of each phase of seed positioning process, the conditions that seed could be positioned by locating notch effectively and continuously were obtained. At the same time, on the basis of previous studies, the image detection algorithm toward seed germ surface orientation and seed tip orientation of qualified seed was improved. In the end, the directional positioning device, the most important component of this machine, was developed with motors as rotary power. Location of seed was found according to image detection information as well as photoelectric positioning signal. After that, seed was grabbed by the way of suction to complete the following directional positioning work: On one hand, according to the image detection information about seed tip orientation, a specified motor drove a specified rotating mechanism of the machine to adjust seed tip orientation, which made seed towards the target direction; on the other hand, based on the image detection information about seed germ surface orientation, i.e. the front or the back, another specified motor drove another specified rotating mechanism of the machine to put seeds in 2 different positions located on each side of the machine. In addition, the required precision of revolving position was analyzed, and accordingly the positioning control mode was discussed and the corresponding operation parameters were set up. In the experiment, the results showed that the detection accuracy of germ surface orientation was 98%, the detection deviation of seed tip orientation was not more than 8°, the locating accuracy of concave notch was 97%, the locating and sucking accuracy of rotating arm was 94%, the locating accuracy of seed placing was 99%, and the angular deviation of seed placing was not more than 10°, which met the design requirements. If one viscous seed band is placed on each side of this machine, which is used to load seeds whose positioning and directing are completed and to make seeds stick on the seed bands evenly and orderly, it will provide condition and foundation for the subsequent directional packaging and seeding.