Geometric Data Calculation of Plants Using Three-Dimensional Scan with Depth Sensor

Abstract

The author has developed a system to evaluate plant growth of quantitative geometrical data, such as stem height, leaf area and fruit volume of the plant by three-dimensional scan using depth sensor. In the prototype system of this paper, the function to automatically perform three-dimensional scanning by the depth sensor by rotating the plant to be measured using an electric turntable was implemented. In addition, functions to calculate stem height and leaf area were implemented. Specifically, first, a polygon model was generated from the point cloud obtained from the three-dimensional scan, and next, the soil region was specified from the direction of the normal vector of each polygon. From the coordinates of the vertices forming the soil region, the equation of the approximate plane was determined by the least squares approximation. The stem height was calculated from the distance between the highest vertex coordinates and the approximate plane. In the polygon model, a region in which normal vectors continuously change between adjacent polygons was determined as a leaf region. The leaf area is calculated by calculating the sum of the areas of polygons constituting the leaf region. As a result of the measurement by the prototype system, the validity of the calculation by the proposed method was suggested.