基于激光点云的苹果果实定位与体积测量方法

A Method for Localization and Volume Measurement of Apple Fruit Based on Laser Point Cloud

快速、准确地监测果实生长状况对于果园管理及果实产量的预测至关重要。相较于传统的技术,激光雷达作为一种主动监测技术,为果实的无损化高精度测量与定位提供了一种多样化的手段。基于激光点云对室内盆栽果树进行建模试验,寻找一种适合于苹果果树果实的三维空间定位以及尺寸检测方法,为苹果生长监测提供重要的科学指导意义。研究建立了一种基于地基激光点云数据的苹果果实空间定位及尺寸检测方法。通过地基激光扫描仪Faro Fcous对苹果树进行数据获取,对点云进行基于RANSAC法的分割,对分割后的点云数据进行二次球面重建并设定阈值进行分类,从而识别出果实部分的点云,并获取果实的空间坐标及果实半径。结果表明,与真实值对比,苹果中心水平距离、角度、高度、苹果体积的均方根误差(RMSE)分别为17.31 mm、12.62°、13.66 mm和3 512 mm^(3),平均绝对百分比误差(MAPE)分别为22.94%、13.63%、5.19%和9.33%,决定系数R2均在0.90以上。该方法可以有效地对苹果果实进行空间快速定位并获取果实体积,同时还可以运用于其他圆形果实的数据提取。

Rapid and precise monitoring of fruit development is essential for orchard management and fruit output forecasting.Compared to conventional technology,liDAR as an active monitoring technology offers a greater variety of nondestructive,high-precision measuring,and positioning options for fruits.On the basis of laser-point-cloud modeling tests on indoor potted apple trees,a three-dimensional spatial positioning and size detection approach suited for apple fruit trees was discovered,which gives vital scientific direction for monitoring apple growth.In this work,a technique for the spatial localization and identification of apple fruit size was developed using laser point cloud data collected from the ground.This article acquires data on apple trees using the Faro Fcous terrestrial laser scanner.The point cloud using the RANSAC approach is segmented,the segmented point cloud data is reconstructed,a threshold to classify is established,the fruit point cloud is identified,and the fruit's spatial coordinates and radius are extracted.In comparison to the actual data,the root mean square errors of the horizontal distance,angle,height,and volume of the apple are 17.31 mm,12.62°,13.66 mm,and 3512 mm',the average absolute percentage errors are 22.94%,13.63%,5.19%,and 9.33%,and the coefficient of determination R²is more than 0.90.This approach is applicable to the extraction of data for various round fruits and can rapidly and accurately find apple fruits and determine their volume.