Static and dynamic 3D contouring by using structured light

Non-destructive optical techniques for 3D shape measuring are fundamental in science, engineering, medicine, and industry. Such 3D data offer advantages over 2D data: shape data are invariant against alteration of the illumination and object motion. One of the major and easy methods to obtain 3D shape is from its contours. There exist several optical techniques for contouring, but the easiest to put into operation is by using linear structured light projection. The present work focuses on the implementation of linear structured light projection techniques for static and dynamic 3D contouring at macro- and micro-levels. Linear structured light as a fringe pattern is projected on the surface to be contoured. White light and laser-illuminating Talbot image are used in order to project the fringe pattern. Projected fringe pattern is captured by a conventional or high-speed CCD camera for image digitalizing and further analysis. Fourier transform method is employed as a tool to obtain a contour-wrap optical phase map. The simple experimental arrangement is adapted for static or dynamic conditions of the surface to contour. Samples that are under harmonic vibration conditions, for example, their vibrating frequency is tuned with that of the capture CCD camera to obtain the mode shape. In the static case one can obtain the topographical comparison before and after the surface subject to a static load or simply its topography. Examples, at micro and macro levels, of static and dynamics surface conditions are shown.