Stripe Image Processing In 3-D Profilometry Measurement Using Grating Projection

Grating projection is a method that captures the 3-D surface profilometry of an object with high speed without any contact. Because of the change of the 3-D surface, the distortion stripes appear when the common rectangular grating or sine grating is projected onto the object surface, which includes information about the 3-D surface profilometry. The images of distortion stripes are taken by CCD camera. The 2-D stripes information is gotten after processing these images. On the basis of mathematic reconstruction model and algorithm, the 3-D surface profilometry data are obtainedThe subject of this paper is about spatial code of stripe images, including its purpose, sorts, processes and criterions of judgment. In chapter 1, the survey of the 3-D shape measurements and the key points in this area are simply introduced. In chapter 2, the characters of the stripe images and systemic error are described. Then the ways of image pretreatment are discussed in chapter 3, where the important parts are about the image filtering and image threshold. Chapter 4 deals with the spatial code. Gray code and border code are analyzed and compared. Then a new method is proposed to improve the effect of the border code. In the end of this chapter, the standard of selecting spatial code is presented. Chapter 5 studies how to use the method of subpixel measurement techniques to improve the precision of the spatial code. In the end, we conclude in the chapter 6.