基于激光视觉的农作物株高测量系统

Crop Height Measurement System Based on Laser Vision

针对目前视觉测量农作物株高技术中存在农作物顶点和底点难以识别的问题,设计了一种基于激光视觉的农作物株高测量系统。该系统针对农作物株高测量特点,改进了三角测量模型,改进后的三角测量模型参数包括相机参数、光平面方程和相机安装参数;依据系统测量模型,该系统标定过程中通过至少一次将棋盘格标定板置于农作物底端点对应水平面的平行平面上,建立农作物底点平面对应的地面坐标系,通过将激光器发出的激光线投射到农作物上,识别农作物顶点。在株高为558.00~1 843.30 mm的农作物上的测试结果表明,测量绝对误差最大值28.30 mm,相对误差最大值为2.17%。该系统标定完成后可实现自动化与实时测量,且测量精度高,具有良好的实用价值。

In order to solve the problem that vertex and bottom points of the crop are difficult to be identified in height measurement of crop by using the visual method,a crop height measurement system based on laser vision was designed. The improved triangulation model,which was designed according to the character of crop height measurement,was used to describe the mathematical model of the system.The model parameters of the crop height measurement system included three parts,which were the parameters of camera, the equation of light plane and camera installation parameter. The model parameters were calibrated by a novel checkerboard method. In the process of the system parameters calibration,the checkerboard must be placed on the parallel plane of the corresponding horizontal plane where the bottom point of the crop was on at least once,to establish the ground coordinate system.Furthermore,the system identified the crop apex by projecting the laser onto the crop. The results of measurement in crop plant height of 558. 00 ~ 1 843. 30 mm showed that the absolute error was no more than 28. 30 mm and the relative error was no more than 2. 17%. Furthermore,the restrictive conditions of the system and suggestions for engineering implementation were given. This system can achieve real-time measurement automatically with a high precision and it had good practical value.