The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008
Figure 6. External shutter device to control the stereo cameras
The cameras were setup at 200mm stereo base distance with
70% stereo overlapping area. The camera system was setup at
700mm object distance (distance between camera to subject).
Table 1 shows the full specifications of Sony DSC F828
professional digital camera.
Imaging Device
2/3 " 8.0 Megapixel Effective
Super HAD™ CCD
Recording Media
Memory Stick® Media, Memory
Stick PRO™ Media, Microdrive
and CompactFlash® Type I/II
Media
Zoom
7X Optical, 2X Digital, 0 -5X
Smart Zoom™ Feature 1, Up to
35X Total Zoom1
Filter Diameter
58mm
Focal Length
7.1mm - 51mm
35mm Equivalent
28mm - 200mm
Aperture
J2.0-2.8
Shutter Speed
Auto (1/8-1/3200 sec), Program
Auto (1-1/3200 sec) Shutter
Priority (30-1/2000), Manual
(30- 1/3200)
Manual Exposure
±2.0 EV, 1/3 EVStep
Color LCD
1.8" 134K Pixels Low
Temperature Polysilicon TFT
Eye-Level Finder
Hi-Speed TTL 0.44" 235K Pixels
Precision TFT LCD
Flash Modes
Auto/Forced On/Forced Off/Slow
Synchro
Flash Effective Range
19 3/4" - 14' 9 3/4" (0.5m - 4.5m)
White Balance
Auto, Daylight, Cloudy,
Fluorescent, Incandescent,
Flash, One-Push Manual
Picture Effects
Solarize, Sepia, Negative Art
Still Image Modes
JPEG (Fine/Standard), TIFF,
RAW, Burst, Auto Bracketing,
Email, Voice Memo
USB Terminal
Supports USB 2.02 High Speed
Battery Type/Capacity
InfoLithium® NP-FM50
1180mAH Rated
Dimensions
5 5/16"x 3 9/16"x 6 3/16"
(134.4 x 91.1 x 156.7mm)
Weight
2.12 lbs (955g) with accessories
Table 1. Sony Cybershot F828 full specifications
2.3 Three dimensional (3D) Laser Scanning System
The basis idea to involve the 3D laser scanning system in the
development of craniofacial spatial data is to capture the
craniofacial surface model in fast and high accuracy data
capturing mode. The 3D surface laser scanning system was
generally designed in two method of operations; time flight
method and triangulation method. For short distance scanning
case (like scanning human face), most of the 3D laser scanners
in the market was design and built using the triangulation
method. The triangulation method is based on triangle concept
that linked the laser device, charge couple device (CCD) camera
and the scanning object.
After the initial evaluation of a few laser scanning products, the
Minolta VI-910 3D laser scanner (as in Figure 7) was selected
and two of these scanners were used to scan the whole
craniofacial area. Each of these laser scanners emits an eye
safe Class I laser (FDA) with >.=690nm at 30mW with an object
to scanner distance of 600-2500mm. The scanner can be
operated in two types of scanning modes; fast mode and fine
mode. The fast mode scanning period is 0.3s while the fine
mode scanning period is 2.5s. Minolta VI-910 used charge
couple device (CCD) camera that can acquire 300,000 3D data
points (fine mode scan) and 78,000 3D data points (fast mode
scan). The scanner output data is the 3D surface of scanning
object with 640 x 480 pixel RGB texture data. The scanner
provide three types of CCD lenses with different focal length(f);
wide(f =8mm), middle (f =14mm) and tele(f =25mm). The
chose of the lens normally based on the size of the object to be
scan and the object distance. Both scanners were setup at
1200mm from the patient. Table 2 show full specifications of
VI-910 laser scanner.
Figure 7. The Minolta VI-910 3D laser scanning system
The Minolta VI-910 can operate the scanning job in two modes
of measurements either “on-line” mode or “off-line” mode.
The “on-line” mode allowed the user to control the scanners
from the computer via Polygon Editing Tool (PET) software
(software that purchased along with the scanner system). The
scanning data can be stored directly to hard disk. While the
offline scanning approach allowed the user to scan object by
using the built in scanning button designed at the back of the
scanner and the scanning data was be stored in the memory
compact flash card and can easily downloaded using digital card
reader that available in the market. For the purposed of
capturing craniofacial 3D spatial data, the on-line measurement
mode was used, look forward that the job was done in the
laboratory (Figure 8).
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