Accurate fringe analysis in a 3D range sensor for the fast measurement of shapes G. Sansoni, F. Docchio, E. Redaelli Laboratory of Optoelectronics University of Brescia, Italy

2 Context of the work National Italian Project: Low-cost 3D imaging and modeling automatic system (LIMA3D) BRESCIA MILANO GENOVA VERONA FIRENZE PALERMO 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 300X400mm 2 Depth range: up to 100mm Measurement uncertainty: 0.3mm

3 What the system is not Optical active triangulation Time-space coding of the meas. volume Fringe projector Video camera Assembly system OPL-3D

4 Winged Victory Sestertius Ferrari 250 MM

5 What the system is Use of low-cost projection device Slide projectorVideo beam Optical active triangulation Projection of a single pattern of light Time space coding of the scene

6 j i U p FW FH Projector Video camera S(i S,j S ) Z g X g Y g O g c c c c O X Y Z p p X O Z Y p p Projection Label: L S dL S S(i S, j S, L S ) LSLS T LTLT T(i S, j S, L T ) S(X S, Y S, Z S ) T(X T,Y T, Z T ) Map of labels j i Phase mapping Camera-projector Calibration Measurement principle

7 Input G C (i,j) Normalization Phase mapping G C,n (i,j) G C,b (i,j) Binarization g f (i,j) g r (i,j) Edge detector g r,f (i,j)g f,f (i,j) Low-pass filtering g r,n (i,j)g f,n (i,j) Amplitude normalization W (i,j) % ATAN2

8 The phase unwrapping Pure spatial approach Spatio-temporal approach (optional)

9 Camera-Projector calibration

10 Sanyo PROxtraX LCD Hitachi KP-D50 Color The prototype

11 Experimental results (1)

12 Exprimental results (2)

13 Metrological characterization

14

15 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