Application of Digital Photogrammetry to Measure Distribution of Tree Postions

The application of digital photogrammetry to measure distribution of tree positions with stereo image couple is introduced in detail, and the procedure of stereo vision applied in forestry environment is explored. Nonlinear error in measure model is adopted in the camera calibration; the interactive correlation matching is used under constraint of epipolar line and edge of tree detected by Canny operator. Results prove that application of digital photogrammetry technology to measure distribution of tree positions can meet demand of precision in experimental conditions.

Measurement of Coordinate Parameter by Multi-baseline Digital Close-range Photogrammetry System and Data Analysis for Jujube

[Objective] The aim was to explore the measurement of coordinate parameter by multi-baseline digital close-range photogrammetry system.[Method] The 3-dimensional coordinate of 8-year-old Jujube was measured by using Lensphoto multi-baseline digital close-range photogrammetry system,and through comparing with measured data of Total Station,the error and accuracy of photogrammetry data were analyzed.[Result] The absolute error of X,Y and Z coordinate was 0-0.014,0-0.018 and 0-0.004 m respectively,and the relative error of X,Y and Z coordinate was less than 0.145%.The significance test of pairs for the photogrammetry data and measured data of Total Station indicated that the space coordinate data of stumpage were accurately measured by using the multi-baseline digital close-range photogrammetry method,and the photogrammetry data meet the need of space coordinate measurement for virtual plant growth simulation.[Conclusion] This study had provided theoretical basis for the growth measurement of virtual plant growth simulation.

Digital 3D Modeling of Whole Garment Based on Structure Illumination

With the coming of information age and the development of computer science, digitalization of whole garment is becoming more and more important. The surface of whole garment is sequent and glossy so that it is lack of the texture characteristic which is the key of digital 3D modeling. According to this reason, the structure illumination is steered into a method of this paper. The paper proposes the method by which 3D model of whole garment is created from 2D image sequences directly but not by the common techniques using general CAD model. In the paper the structure illumination is generated by the slide projector and the modeling of whole garment is based on the strict theory of the digital photogrammetry, computer vision and image processing pattern recognition. Because whole garment is lack of the applicable texture for matching, the characteristic texture generated by the structure illumination is added onto the surface of whole garment. After the characteristic texture is extracted from images and is matched well, 3D coordinates of the characteristic texture can be calculated out by the space forward intersection. Then the whole garment model is acquired by connecting all neighhour space points in the TIN and rendering the real texture of whole garment automatically. The 3D modeling method is untouched so that it is nondestructive which is just suitable for the messaline and the clothing. The method of whole garment 3D modeling proposed in the paper is flexible, effective and practical, which is confirmed by the results of the reconstructing experiments.

A TECHNIQUE OF DIGITAL SURFACE MODEL GENERATION

It is usually a time-consuming process to real-time set up 3D digital surface model(DSM) of an object with complex surface.On the basis of the architectural survey project of"Chilin Nunnery Reconstruction",this paper investigates an easy and feasible way,that is,on project site,applying digital close range photogrammetry and CAD technique to establish the DSM for simulating ancient architectures with complex surface.The method has been proved very effective in practice.

Spatiotemporal evolution rule of rocks fracture surrounding gob-side roadway with model experiments

A series of plane-strain physical model experiments are carried out to study the spatiotemporal evolution rule of rocks fracture surrounding gob-side roadway, which is subjected to the pressure induced by the mining process. The digital photogrammetry technology and large deformation analysis method are applied to measure the deformation and fracture of surrounding rocks. The experimental results indicate that the deformation and fracture of coal pillars are the cause to the instability and failure of the surrounding rocks. The spatiotemporal evolution rule of the rock deformation and fracture surrounding gob-side roadway is obtained. The coal pillar and the roof near coal pillar should be strengthened in support design. The engineering application results also can provide a useful guide that the combined support with wire meshes, beam, anchor bolt and cable is an effective method.

Rapid Texture Mapping from Image Sequences for Building Geometry Model

An effective approach, mapping the texture for building model based on the digital photogrammetric theory, is proposed. The easily-acquired image sequences from digital video camera on helicopter are used as texture resource, and the correspondence between the space edge in building geometry model and its line feature in image sequences is determined semi-automatically. The experimental results in production of three-dimensional data for car navigation show us an attractive future both in efficiency and effect.

Integrated Computer Aided Shoe-Making System

Shoemaking is one of the areas where CAD/CAM application is rapidly increasing.This paper introduces an integrated computer aided shoemaking system including human foot measuring,last (wooden model)measuring,last CAD/CAM and pattern CAD/CAM.The project was supported by the 7th national economical 5 year plan.High technologies,suh as digital image processing,pattern rcognition,advanced geometrical modeling and a series of sophisticated equipments and devices are ap- plied in this integrated system.Parts of the system have become commercial products.

Advanced stability analysis method for the tunnel face in jointed rock mass based on DFN-DEM

An advanced stability analysis of surrounding rock can assure safe construction in tunnels.However,in traditional analysis methods,geometric information on the rock mass discontinuities is obtained by a geological compass and treated as an infinitely expanded plane in a numerical simulation,which is inaccurate in both geometric and numerical models.To solve this problem,this paper studied a control network and an image stitch method to assess the accuracy of a geometric model and proposed a more accurate method to obtain the geometric information of rock mass discontinuities based on digital photogrammetry.Based on discrete fracture network and discrete element method(DFN-DEM),this paper treated the rock mass discontinuities obtained by digital photogrammetry as finite disk planes and simulated the excavation process of the Qianyu tunnel.According to the simulation results,this paper determined the specific location of the collapse disaster on the tunnel face,which is of great significance to tunnel support design.Comparing the deformation of the surrounding rock mass on the tunnel face in the simulation results with the actual situation,this paper verified the feasible accuracy of this method in analysing the stability of the surrounding rock mass on a tunnel face in advance.