The Research Of Key Technology On Three-dimension Reconstruction Of Specular Object

With the development of detection technology and the continuous improvement of industrial manufacturing precision,the detection of two-dimensional image information cannot meet the quality inspection requirements on some occasions.In many cases,the three-dimensional information of the object is required as a criterion for evaluating the manufacturing quality of the product.There are many kinds of specular objects in the real world,such as solar concentrator mirror,silicon wafers for solar cells,the painted shell of automotive,eyeglass lenses,glass panels of the display screen,reflective laptop casing,and optical reflectors.The three-dimensional information of reflective surfaces has a guiding role in product manufacturing and can help improve production processes and improve product quality.Therefore,it is of great significance to study the three-dimensional reconstruction technology of specular objects.Based on the above research significance,this paper mainly seeks for an efficient,precise and economical 3D reconstruction technology for specular objects,analyzes the three-dimensional reconstruction process of specular objects,and builds experimental equipment for specular object measurement.The main work of this dissertation is as follows:(1)This paper introduces and analyzes several common three-dimensional reconstruction techniques of objects,compares the advantages and disadvantages of several three-dimensional reconstruction methods,and points out that the fringe reflection method is a method suitable for three-dimensional reconstruction of specular objects.The principle of the fringe reflection method for measuring the reflection surface was studied in detail.The phase acquisition and gradient acquisition method were introduced.The gradient integral reconstruction algorithm was studied in detail.(2)The principle of Southwell integration algorithm is analyzed in detail.An improved Southwell algorithm is proposed.The reconstruction result of improved algorithm and Southwell algorithm and several other algorithms are compared using simulation data and experimental data.The improved algorithm is proved to be robust and has high reconstruction quality.(3)According to the principle of fringe reflection measurement,a specular surface profile measuring device has been set up.The 3D shape of concave spherical reflector has been successfully reconstructed,and its reconstruction error is less than 0.5% compared with standard parameter(measured by Taylor Hobson).The system error of the measuring device is analyzed,and several factors that may cause the measurement error are pointed out.(4)Based on traditional experimental methods,an improved experimental method for rotationally symmetric reflector is proposed,which significantly improves the accuracy of 3D reconstruction of rotationally symmetric surfaces.(5)Using the existing measuring device,we have detected the flaw in the glass panel of display screen and the reflective shell of laptop.We successfully detected small flaws in the reflective surface using the fringe modulation diagram,which overcomes the difficulty in the detection of reflective surfaces by ordinary illumination mode.