Simultaneous Data Acquisition for Outside and Inside of the Relics using Multi-sensor
Hiroshi Yokoyama, Hirofumi Chikatsu
Department of Civil Engineering, Tokyo Denki University
Hatoyama, Saitama, 350-0394?JAPAN
Tel: +81-492-96-2911, FAX: +81-492-96-6501
E-Mail: VYI04050@nifty.ne.jp, chikatsu@g.dendai.ac.jp
Hiroshi Yokoyama, Hirofumi Chikatsu
Department of Civil Engineering, Tokyo Denki University
Hatoyama, Saitama, 350-0394?JAPAN
Tel: +81-492-96-2911, FAX: +81-492-96-6501
E-Mail: VYI04050@nifty.ne.jp, chikatsu@g.dendai.ac.jp
Abstract
Many archeological sites are being excavated every year in Japan, and abundant relics recovered from these sites have to be drawn by archeologists for archival records taking a great deal of time, labor and skill.
For saving labor and time, automatic drawing and modeling system for relics was developed by the authors. However, these systems can't films the inside-image of relics.
For a solution of the inside measurement, a small CCD camera was added to the measurement system using turntable. This CCD camera sets around the turn center of turntable and another CCD camera sets in front of the relic. These CCD cameras continue film the inside of relic till the turntable does the 1 circumference. After the film, the system can get the inside and an outside 3 D shape at same time.
1. Introduction
Large quantities of remains are discovered currently in all parts of Japan. Relics excavated from these remains are enormous number (In 1996, Excavated number is over 10,000.). In Japan, all relics need to record. A record is left unfinished with ortho-projection images and edged images. Shortening of investigation period is pursued in this record work from enormous labor being spent.
In these days, there is a demand to want to leave 3D shape record of relics with technical development of CG technology at same time. For these demands and in order to reduce work of human power, we investigated ortho-projection and drawing system and the pattern extraction technology that used CCD cameras from 1994. In the ortho-projection system, shape data of relics lacked partially. The part which illumination does not hit is a cause (occlusion). We developed a measurement system to film using a turntable and source of light from two directions (3D measurement system using line laser-beams). Fig.1 shows measurement result of the turntable system that developed for occlusion problem in ortho projection system. But this system measure only outside three-dimension shape.
Fig 1. 3D Image of outside
We examined the measurement method of simultaneous data acquisition for outside and inside of the relics.
2. Measurement System
Figure2 shows the developed measurement system and Table 1 shows experiment components.
Fig 2. Measurement System
Table 1 Experiment Components
This measurement system consists of turn table and line lasers, CCD cameras, PC for image processing. CCD cameras film the target lighted up in being linear with line lasers. Each CCD camera films outside image and inside image at same time. CCD cameras continue film till the turntable does the 1 circumference.
The system grasps three dimensions of outside and inside shape target using line-images and angles of rotation degree of these times. Figure 3 shows position relation of line lasers and CCD camera. Line lasers for outside are installed so that respect of light intersects at the center of the turntable. As for the respects of these lasers, right and left course each includes 45 deg. of leaning for the line that connected the turn center with CCD camera. This situation of the line lasers for outside is made for the target with complicated form. If a line laser illuminates the target from a direction, the omission of images may happen from shape of target. In this method, the CCD camera for out side can film line images lighting up the target from positions named objection simultaneously. As the result, this system can get three-dimension shape without lack of data that caused by occlusion.
Fig 3. Position Relation of Line Lasers and CCD cameraa
A line laser for inside is installed so that respect of light surface lights up the center of turntable and CCD camera for outside. At this system, the line laser for inside lights up the target on turntable from the table upper part and lights up inside of the target by a mirror.
In this investigation, line lasers for outside light up the part that a line laser did not light up with traditional method (1 course type) by lighting it up from 2 directions and line laser for inside lights up inside of the target. CCD camera of the front films two lines appearing on the relic surface lighted up with line lasers and CCD camera of the inside films a line appearing on the relic surface of inside lighted up with line laser at same time.
This system demand distance from the turn center, height from table base, color information (brightness) of each point about part of relics represented with lines. As a result, simultaneous data acquisition for outside and inside of the relics using multi-sensor and adding angle of rotation degree of turntable become possible. Explains the details of measurement method at later.
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.
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.
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
Many archeological sites are being excavated every year in Japan, and abundant relics recovered from these sites have to be drawn by archeologists for archival records taking a great deal of time, labor and skill.
For saving labor and time, automatic drawing and modeling system for relics was developed by the authors. However, these systems can't films the inside-image of relics.
For a solution of the inside measurement, a small CCD camera was added to the measurement system using turntable. This CCD camera sets around the turn center of turntable and another CCD camera sets in front of the relic. These CCD cameras continue film the inside of relic till the turntable does the 1 circumference. After the film, the system can get the inside and an outside 3 D shape at same time.
1. Introduction
Large quantities of remains are discovered currently in all parts of Japan. Relics excavated from these remains are enormous number (In 1996, Excavated number is over 10,000.). In Japan, all relics need to record. A record is left unfinished with ortho-projection images and edged images. Shortening of investigation period is pursued in this record work from enormous labor being spent.
In these days, there is a demand to want to leave 3D shape record of relics with technical development of CG technology at same time. For these demands and in order to reduce work of human power, we investigated ortho-projection and drawing system and the pattern extraction technology that used CCD cameras from 1994. In the ortho-projection system, shape data of relics lacked partially. The part which illumination does not hit is a cause (occlusion). We developed a measurement system to film using a turntable and source of light from two directions (3D measurement system using line laser-beams). Fig.1 shows measurement result of the turntable system that developed for occlusion problem in ortho projection system. But this system measure only outside three-dimension shape.
Fig 1. 3D Image of outside
We examined the measurement method of simultaneous data acquisition for outside and inside of the relics.
2. Measurement System
Figure2 shows the developed measurement system and Table 1 shows experiment components.
Fig 2. Measurement System
| CCD Camera | For out side: XC-75 (SONY) CCD: 768pixel(w)*494pixel(h) For in side: WAT-660D (WATEC) CCD: 510pixel(w)*492pixel(h) |
| Line Laser | SMF-501L-670 (M)-10-30 (MORITEX Wave Length: 670nm |
| Turntable (Motor) | UDX-5114 (ORIENTAL MOTOR) Minimum angle of rotation: 0.36deg |
| PC | CPU: Pentium 133MHz, Memory: 64MB |
| Image Processing Board | MTAT-CL (Micro Technica) (Use ISA BUS), Image: 512dot*512dot |
Table 1 Experiment Components
This measurement system consists of turn table and line lasers, CCD cameras, PC for image processing. CCD cameras film the target lighted up in being linear with line lasers. Each CCD camera films outside image and inside image at same time. CCD cameras continue film till the turntable does the 1 circumference.
The system grasps three dimensions of outside and inside shape target using line-images and angles of rotation degree of these times. Figure 3 shows position relation of line lasers and CCD camera. Line lasers for outside are installed so that respect of light intersects at the center of the turntable. As for the respects of these lasers, right and left course each includes 45 deg. of leaning for the line that connected the turn center with CCD camera. This situation of the line lasers for outside is made for the target with complicated form. If a line laser illuminates the target from a direction, the omission of images may happen from shape of target. In this method, the CCD camera for out side can film line images lighting up the target from positions named objection simultaneously. As the result, this system can get three-dimension shape without lack of data that caused by occlusion.
Fig 3. Position Relation of Line Lasers and CCD cameraa
A line laser for inside is installed so that respect of light surface lights up the center of turntable and CCD camera for outside. At this system, the line laser for inside lights up the target on turntable from the table upper part and lights up inside of the target by a mirror.
In this investigation, line lasers for outside light up the part that a line laser did not light up with traditional method (1 course type) by lighting it up from 2 directions and line laser for inside lights up inside of the target. CCD camera of the front films two lines appearing on the relic surface lighted up with line lasers and CCD camera of the inside films a line appearing on the relic surface of inside lighted up with line laser at same time.
This system demand distance from the turn center, height from table base, color information (brightness) of each point about part of relics represented with lines. As a result, simultaneous data acquisition for outside and inside of the relics using multi-sensor and adding angle of rotation degree of turntable become possible. Explains the details of measurement method at later.
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