Abstract
In this paper, we describe a structure and an algorithm of a newly developed 3-D deformation measurement system, and show some results of its application to a dental prosthodontical investigation of a human oral soft tissue under various impression pressures.
This system is composed of a fixed TV camera and vertically scanning projectors. The projectors generate a moving 3-D illumination distribution in front of an object. A height difference and a reflectance ratio between two objects are coded in a time difference and an amplitude ratio respectively between two sequences of images of them. Using gradient-based least squares algorithms, we decode these quantities precisely and efficiently. The remarkable advantages of this system are 1) it can be free from occlusion because of its vertical scanning and imaging geometry, 2) it doesn't need any precise geometry except for the reproducibility of the vertical scanning stage, 3) it can measure a height difference between unequal reflectance objects as well as unknownly textured surfaces, and 4) it completes one aerial measurement including computation within only 10 seconds while keeping the 5μm precision and 1mm range-ability.
Using this system, we investigate the influence of the various impression procedures on the magnitude of soft tissue displacement. The principle of this measurement system and the results of this application are presented.
