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This research focuses on the development and characterization of a low-cost optical digitizer for fast and accurate shape measurement using fringe analysis. The system utilizes a single grating projection and time-space coding to achieve high-quality results. Results from metrological characterization and experimentation with high-resolution and 3CCD color cameras are presented.
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G. Sansoni, F. Docchio, E. RedaelliLaboratory of OptoelectronicsUniversity of Brescia, Italy Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes
BRESCIA MILANO FIRENZE VERONA GENOVA PALERMO Context of the work National Italian Project: Low-cost 3D imaging and modeling automatic system (LIMA3D) • BRESCIA • Laboratory of Optoelectronics • Design, development and metrological characterization of a low-cost optical digitizer based on the projection of a single grating of non-coherent light • Field of View (FOV): up to 300X400mm2 • Depth range: up to 100mm • Measurement uncertainty: 0.3mm
What the system is not • Optical active triangulation • Time-space coding of the meas. volume Fringe projector Video camera Assembly system OPL-3D
Winged Victory Sestertius Ferrari 250 MM
What the system is • Use of low-cost projection device Slide projector Video beam • Optical active triangulation • Projection of a single pattern of light • Time space coding of the scene
Map of labels LT LS t Y X l p p T Z p O S p d L Z j j c i i O X X c c g Y c Z g O Y g S’(i , j ) g S S Measurement principle FW Phase mapping Projection Label: LS Projector U p S(iS, jS, LS) T(iS, jS, LT) FH S(XS, YS, ZS) Video camera T(XT,YT, ZT) Camera-projector Calibration
Input GC(i,j) Normalization GC,n(i,j) Binarization GC,b(i,j) Edge detector gr(i,j) gf(i,j) Low-pass filtering gr,f(i,j) gf,f(i,j) Amplitude normalization gr,n(i,j) gf,n(i,j) % FW(i,j) ATAN2 Phase mapping
The phase unwrapping • Pure spatial approach • Spatio-temporal approach (optional)
Sanyo PROxtraX LCD Hitachi KP-D50 Color The prototype
Conclusions • Low-cost 3D system based on phase measurement • Characterization of the measurement performance • Experimentation with high resolution cameras • Experimentation with a 3CCD color camera