3.Measurement Method
This system turn front course into the standard and do each camera calibration. We calculate a position of CCD camera with each respect as the front (XY plane, Base plane). Then, we calculate the existing turn center to the image.
We demand a plane coordinate (distance from the turn center and height from the table base) afterwards. We calculate three dimensions of shape using this plane coordinate and angles of rotation degree of the table.
But, in this system, we must unify coordinate systems. Because, we light it up from 3 directions at inside and outside, and these light surface (line lasers) have original coordinate systems.
Based on the fact of light surfaces concentrate on the turn center, we spin each coordinate system in turn center and adjust coordinate systems. By this work, coordinate systems at each surface are standardized.
Table 2 shows the numerical formula that we used to demand shape data (three-dimension data). This expression is generally used for three dimensions of coordinate transformation.
Axis\
Coordinate |
Y-axis |
X-axis |
Z-axis |
| X |
X'=X*cos·+Z*sin· |
X'=X |
X'=X*cos·-Y*sin· |
| Y |
Y'=Y |
Y'=Y*cos·-Z*sin· |
Y'=X*sin·+Y*cos· |
| Z |
Z'=-X*sin·+Z*cos· |
Z'=Y*sin·+Z*cos· |
Z'=Z |
Table 2 Turn Conversion Expressions
Here,
(X,Y,Z)= Coordinate Before Conversion
(X',Y',Z')= Coordinate After Conversion
·=Rotation Angle
We use only the expression of Y-axis circumference when we pursue three dimensions of coordinates from plane coordinate and angle of rotation degree. By these expressions, we standardize coordinate systems in one. Because, three coordinate systems exist. Crossing angle of two base planes at outside are 45 degrees to base plane of inside. So, we turn the light plane of inside into standard. We just store three dimensions of information at inside plane. As for three dimensions of information of outside plane, ±45 degree turns to Y-axis circumference. We record the result that turned. Three coordinate systems are unified hereby.
4. Measerment Result
Figure4 shows measurement result by this system. This system needs about 10 minutes by measurement of once, now. This image is made by whole three dimensions shape data of outside shape and part three dimensions shape data of inside. Because view of inside camera is small, there is not a total measurement.
This system can acquire development image at same time. Figure 8 shows the development image of inside. In Figure5, only part of inside data is represented. It was caused by limited view of inside CCD camera. To this solution, we think about move a camera and grasp move volume (use the volume at camera calibration). By this work, we will measure the whole inside shape data.
By this system, simultaneous data acquisitions for outside and inside are realized. So, quality of measurement result improves.
 |
(a) Target |
(b) 3D shape data |
Fig.4 Measurement Result
Fig.5 Development Image of inside
5. Summary
This system cans simultaneous data acquisition for outside and inside of the relics using multi-sensor.
The following things are nominated for future subject.
·Into Color
·High picture element correspondence
Reference
- H.YOKOYAMA, K.HATANO, H.CHIKATSU, 1996, Ortho Projection and Drawing for Archeological Artifacts of Complicated Form, International Archives of Photogrammetry and Remote Sensing, Vienna, Vol.XXXI, PartB5, pp.95-100
- Devid MARR, 1982, VISION, W.H.Freemen and Company
- H.YOKOYAMA, H.CHIKATSU, 2000, 3D Measurement System Using Line Laser for Archeological Artifacts, International Archives of Photogrametry and Remote Sensing, Amsterdam, Vol.XIX, PartB5
