The Research Of Interactive Measurement For Wheat Geometry,Morphology Based On The Point Cloud

As the research focus of digital agriculture and virtual reality etc. interdisciplinary, virtual plant has broad application prospects in the field of agriculture, forestry, ecology, remote sensing, etc. As a foundation work of virtual plant modeling, getting the plant geometry morphology data accurately and conveniently is important significance. In the plant morphology modeling based process, traditional geometric measurements of morphology structure uses mechanical measuring instruments,for example vernier cliper, protractor etc. and the measurement data is low acuracy and it may destroy the plant. With the development of three-dimensional information collecting technology, making quick obtaining the plant surface precision of point cloud data as possible, and provide a new method for abtaining the geometry data of plants. Currently, measueing the plant geometry the morphology that using the 3D point cloud data is reconstructing the point cloud and uses the CAD software. Although this methon can obtain a variety of gemetric value of plants, but before the measurement, it needs to reconstruction the point cloud etc. complex processing. In this paper, using wheat 3D point cloud data as the research object, to accurate, interactive non-destructive measure the geometry morphology data of plant. Research carried out interactive measurements of wheat geometry morphology. The main results are as follows:1. Using the wheat plants point cloud data as the research object, we propose a method for mapping screen pixel to object surface coordinates point. This method consists three point cloud processing compoents and the compoents are exraction of point cloud of user sight near, computing valid point set of the point cloud near the sight, solving the intersection of the line of sight and the object’s surface. Throuth the mapping method, the window coodinate of the user’s mouse can be mapped to surface of the object that is rendered. The method also provides the basis algorithms for establishing interactive processing of the point cloud data.2. Based on the method that map the screen pexel to coordinates of object surface, interactive geometry value selected and geometry value calculations was designed and forming an interactive geometry measurement methonds using point cloud data. This method supports interactive selection and calculation of geometry value, for example, coordinate of a point, normal vector at a point, curvature at a point, the straight line equation, the length of a curve, the equation of a cuerve, a angle, a projected area etc. In the three-dimensional point cloud data as input, the method can acccurate and fast measure the complexgeo merry value of the object.3. Based on the interactive measurement method of geometry morphology using pointcloud that was proposed in this paper, an interactive measurement systems of geometry morphology was developed. With the wheat plants point cloud data as input, the system can quickly interactive measureing the complex geometry value of wheat spike length, vein curve, the curve of leves edge, such as the projected area of the plant. Compared with traditional methods of measurement, the method has many advantages of high speed, high precision and non-damage etc.