Document Type: Original Article
School of Surveying and Geospatial Engineering, College of Engineering, University of Tehran
Three-dimensional measurement of coordinates in different optical metrology techniques involves the measurement of image coordinates and/or phase values as observations as well as system parameters. These system parameters are usually determined through a calibration process. Self-calibration of digital fringe projection systems takes advantage of the fringe projection technique in a photogrammetric mathematical model. Many pieces of research have shown the capability of this technique which is called phasogrammetry, to achieve high accuracy and reliability. However, the difference between projection lenses and imaging lenses has not been investigated yet. In this paper, a set of experiments is performed to analyze the behavior of systematic errors in digital projectors as the basic component of this method. The results indicate that the well-known physical model of camera in close range photogrammetry might be used for digital projectors. The best results if the 3D measurement of the test object achieved where the first term of radial distortion K1 and the first in-plane distortion parameter B1 are involved in the self-calibration of the digital fringe projection system.