基于视触觉感知的番茄尺寸和姿态解析方法

Analytical Method and Evaluation of Tomato Size and PostureBased on Visual and Tactile Perception

针对传统农业机器人抓取过程中视觉识别番茄果实尺寸和姿态存在枝叶遮挡的问题,提出了一种基于视触觉感知的番茄尺寸和姿态解析方法。在果实抓取过程中通过视触觉传感器得到果实外轮廓接触局部点云信息,然后通过相机参数标定以及各手指关节变换矩阵,将不同传感器坐标系下的点云信息变换到同一基坐标系下,进而通过点云改进PCA算法和ICP算法解析抓取果实的尺寸和姿态信息。为了评估所提出解析方法的性能,在实验室环境下进行了番茄尺寸和姿态检测试验。通过游标卡尺测量和深度相机扫描分别获得番茄果实尺寸和姿态的真实值,并与本文方法解析结果进行对比。检测试验结果表明,本文方法获得的番茄横向尺寸和纵向尺寸平均相对误差分别为8.66%和11.08%,番茄果轴与视场投影面的水平夹角和垂直偏转角平均相对误差分别为10.03%和14.02%。本文方法解析的番茄果实尺寸与姿态信息,可应用于番茄果实抓取过程中的姿态调控,从而提高番茄果实抓取采摘的可靠性。

In order to solve the problem that the branches and leaves were obscured in the visual recognition of tomato fruit size and posture during the grasping process of traditional agricultural robots,a method of tomato size and posture analysis based on visual and tactile perception was proposed.In the process of fruit grasping,the local point cloud information of fruit contour contact was obtained by visual and tactile sensors,and then the point cloud information under different sensor coordinate systems was transformed to the same base coordinate system by camera parameter calibration and finger joint transformation matrix,and then the size and posture information of fruit was analyzed by point cloud improved PCA algorithm and ICP algorithm.In order to evaluate the performance of the proposed analytical method,tomato size and posture tests were performed in the laboratory environment.The real values of tomato fruit size and posture were obtained by vernier caliper measurement and depth camera scanning,and compared with the presented analytical results.The test results showed that the average errors of transverse and longitudinal dimensions of tomato obtained by this method were 8.66%and 11.08%,and the average errors of horizontal angle and vertical deflection angle of tomato fruit axis and projection plane were 10.03%and 14.02%.The size and posture information of tomato fruit analyzed by the proposed method can be applied to the posture regulation of tomato fruit grasping process,so as to improve the reliability of tomato fruit grasping and picking.