|One Idea on a Three Dimensional Measuring System Using Light Intensity Modulation
Ikumatsu Fujimoto, In-Ho Cho, Jeong-Hyeon Pak, and Young-Sik Pyoun
International Journal of Control, Automation, and Systems, vol. 3, no. 1, pp.130-136, 2005
Abstract : A new optical digitizing system for determining the position of a cursor in three dimensions(3D) and an experimental device for its measurement are presented. A semi-passive system using light intensity modulation, a technology that is well known in radar ranging, is employed in order to overcome precision limitations imposed by background light. This system consists of a charge-coupled device camera placed before a rotating mirror and a light-emitting diode whose intensity is modulated. Using a Fresnel pattern for light modulation, it is verified that a substantial improvement of the signal to noise ratio is realized for the background noise and that a resolution of less than a single pixel can be achieved. This opens the doorway to the realization of high precision 3D digitized measurement. We further propose that a 3D position measurement with a monocular optical system can be realized by a numerical experiment if a linear-period modulated waveform is adopted as the light-modulating one.
Keyword : 3D position measurement, rotating scanning mechanism, Fresnel diffraction pattern, light intensity modulation, linear-period modulation.