Research On Plant 3D Reconstruction And Leaf Segmentation Based On Fringe Projection

With the rapid development of imaging systems and the great improvement of computer computing performance,the three-dimensional morphological restoration of plant leaves has received widespread attention.Plant leaf segmentation,as an important task of highthroughput phenotypes,is particularly important in the field of agriculture and is the focus of biological research.Therefore,it is of great significance to study how to implement the high precision,high efficiency and low cost three-dimensional morphology measurement of crop leaves.Plant phenotypes refer to complex traits in different tissues from plant organs to canopies,including the structure and composition of plant growth and associated with production.Plant leaves,which account for the largest proportion of most plant organs,are the main components of active substances used in photosynthesis in plants.The changes in leaf shape,texture or color represent whether it is subjected to biological stress(pests and diseases)or antibiotic stress(drought).Therefore,the development of computer intelligence is applied to agriculture to realize the interactive segmentation,recognition and classification of leaves.The results obtained can play a role in rapid early warning,which is helpful to improve the yield of crops and the quality of agricultural products.Through investigation,the present situation of the application of intelligent agriculture at home and abroad and the 2D and 3D research in computer vision in the plant leaf phenotype,combined with more complex and plant growth and phenotype of blade,3 d reconstruction based on structured light technology to plant and leaf phenotypic parameters research,realize the visual description of plant morphological structure and plant phenotypic analysis,It is helpful for the research of genetic breeding,irrigation and fergation.In this study,a three-dimensional morphology measurement platform for plant leaves was built based on fringe grating projection.Based on the understanding of the imaging principle of structured light,a projector with small module volume and considerable field of view and a camera with high imaging quality were specified as the main components of the system for the requirements of plant three-dimensional reconstruction and leaf segmentation.At the same time,the 3D reconstruction code is encapsulated,and a set of GUI operation interface of the plant leaf 3D measurement system based on MATLAB software is designed,which provides tools for subsequent image extraction,measurement and analysis.The phase coding algorithm and dual-frequency phase unwrapping algorithm in fringe projection are studied in order to obtain the no-difference measurement of 3D phenotype,and the unwrapping error in phase unwrapping is analyzed.Aiming at the fringe order detection errors caused by random noise,camera and projector defocus in the traditional phase unwrapping algorithm to solve the absolute phase,two different improved methods were proposed based on the two time phase unwrapping methods and combining with the truncation phase properties,and the simulation experiments and experimental verification were carried out.By comparing the results of the traditional method with the improved algorithm,it is proved that the proposed method can solve the problem of phase unwrapping error to some extent,and provide a solution for the high-precision three-dimensional measurement of blades.Finally,the experiment of plant 3D reconstruction and leaf segmentation based on fringe projection technology was carried out.The principle of phase unwrapping of multifrequency algorithm and phase coding algorithm is analyzed,and the 3D morphology of multi-blade and single blade is extracted respectively.On this basis,combining with phase shift invariance,change projection fringe order to calculate the wrapped phase of different groups,and according to the calculating of wrapped phase on the existence of two kinds of singular feature points,using the method of calculating the jump points of the gradient operator,to obtain the result of intersection operation,again carries on the connected domain marked segmentation,to obtain a single leaf division.On the basis of the successful segmentation of a single blade,the area of a single blade is calculated,and the linear relationship between the area obtained by the mesh method and the corrected blade area in this paper is established.Focusing on optical measurement technology,this paper carried out research on the three-dimensional reconstruction of plants and leaf segmentation by fringe projection technology.The system design,phase unfurling error,three-dimensional morphology recovery of leaves and phenotypic parameter calculation of plants were experimentally analyzed.The effectiveness of the proposed method was verified through simulation and real experiments.It provides technical support for the realization of high-precision,highefficiency and low-cost three-dimensional morphology measurement of crop leaves under non-contact measurement.