U. Pavlovcic et al., "Handheld 3D Measuring System Based on DSLR Camera", in Proc. of 3rd Int. Conf. on 3D Body Scanning Technologies, Lugano, Switzerland, 2012, pp. 74-80, http://dx.doi.org/10.15221/12.074.
Handheld 3D Measuring System Based on DSLR Camera
Urban PAVLOVCIC, Matija JEZERSEK, Janez MOZINA
Faculty of Mechanical Engineering, University of Ljubljana, Ljubljana, Slovenia
A handheld color 3D measuring system is presented. It consists of a commercial DSLR camera body, a 50mm fixed focal length lens and a grating projection system with a built-in camera flash used as a light source. The grating mask is composed of up to 140 equally spaced stripes, with the stripes period of 48micron. The projector uses 25mm focal length lens. All parts with the exception of the grating projection optics and a ring-shaped connection arm are commercially available.
The 3D shape is reconstructed from a single image using the Fourier Transform Profilometry method. 3D reconstruction based on the triangulation principle is performed after the phase unwrapping. The measuring system is calibrated using the reference geometry method. The precision of the measuring system is 1.4mm for measuring range 700x520x400mm at the distance of 2000mm and 0.5mm for measuring range 300x260x200mm at the distance of 1000mm. The image acquisition time can be as short as 1/200s.
The measuring system is used in various medical research studies in cooperation with the Neurologic Clinic, Department of Dermatovenerology and Department of Traumatology from University Medical Center Ljubljana. In one of the applications the orientation of the human head with respect to the torso is measured to accurately diagnose and to evaluate the course of treatment of patients with torticollis disease. In a second application the skin erosion and wound shape before and after the treatment are monitored. The apparatus has proven to be a robust and easy to use, which is a precondition for efficient, fast and accurate measurements.
Three-dimensional measurement, surface digitalization, biometrics, profilometry, measurement systems, triangulation, image processing, machine vision
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