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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
Mirrors
Both axes for laser range finder and amateur digital camera
are adjusted by two mirrors (mirror and half mirror).
Camera
OLYMPUS C-3040 (3.14 mega pixels)
* Laser profiler
Leica LDS-1 (accuracy is +3mm to 40m)
+ PC
Pentium Ill 850Hz
Laser range finder and amateur digital camera are
controlled by personal computer, and captured image data
and measured distance data are recorded on hard disk
(mounted on 10GB).
+ Monitor
6.4-inch display is used as a finder and PC monitor.
Figure 1. Appearance of the IBIM
3. CAMERA CALIBRATION
In order to perform camera calibration, at least 6 space
distances for the points, which show feature on object field
from the center of a camera, have to be measured by laser
profiler. These feature points are defined as temporal GCP in
this paper. Then, 36 unknown parameters such as exterior
orientation parameters for both camera {(Xo,, Yor, Zoi, €. Q1,
Kr), (Xog, Yon, Zor. @r, Or Kr)}, interior orientation parameters
(f (focal length), xy y, (principal points), a;, a», (scale factor),
k; (lens distortion)} and 3D coordinates for the 6 temporal
GCPs should be calculated. However, X or Y-axis and 2 points,
which have the same height value or height values for 2 points,
are required to prevent rotations. Therefore, origin point and the
point, which define the X-axis direction, are selected. 3D
coordinates for the origin point and the point are assumed (0, 0,
0) and (X,, 0, 0) respectively. As a result, 30 parameters
become unknowns, and these unknown parameters are
calculated by collinearity condition and space distances
simultaneously. Detail calibration procedures are as follows.
Figure 3. Concept of measurement by the IBIM
Dos Measurement ....., geeretee septies Control Part. eee ;
: Part i : ;
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: Laser Wf i ‘
: Range Finder |... » | HDD | | CPU | =
i i Distance | e
1 5
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y 4 :
1 =
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1
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pren eee ee frei i :
; Control ı Image :
E : [1 en = —————— - Data
; Lj] Digital
Camera | h.n Video
Half Image Capture Battery
Mirror Data. Device
sini vie Image Acquiring Part eee] HAMM 3
Figure 2. Configuration of the IBIM