Synthetic Point Profile
®c—np0<< 0Q
Real Point Profile
g
r
e
y
v
a
|
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Figure 1b: Synthetic and real point profiles
While IMAGE1 to IMAGE3 show
very realistic features, IMAGE4 ition
and IMAGE5 demonstrate the
effect of occlusions, point
disturbances and varying
backgrounds as they may occur
only in very few practical cases.
3.2 Testfield Images
In cooperation with Rollei Fototechnic, Germany, a set of
8 digital images showing a photogrammetric test field with
approx. 45 object points has been taken. For this purpose
a fully-digital high-resolution CCD camera Rollei 6008 /
ChipPack has been used.
By default this testfield is used for standard camera
calibrations in the factory. It is prepared with 55 retro-
reflective targets on a plane black surface, and additional
3 points in spatial positions. The object has been imaged
from eight different locations according to the standards
of testfield calibration network design (Wester-
Ebbinghaus 1986). This configuration allows for the
Image5
Image4
size rotation noise
Table 1: Description of synthetic images
VARIATIONS
occlusion
+ +
+ +
+ + + +
+ + + +
complete determination of all parameters of interior
orientation without knowledge of control points.
The ChipPack camera consists of a 2K x 2K CCD frame
transfer imaging device. Image signals are digitized
directly within the camera electronics in order to avoid
analog video transfer and processing. The CCD sensor
produces greylevels of 10 bit resolution which are later
transformed to 8 bit (256 greylevels). Camera control and
image transfer is performed by a SCSI interface. The
camera is equipped with a ring flash device which gives a
shadow-free illumination onto the retro-targets (Godding
& Woytowicz 1995).
Image3
Figure 2: Synthetic images with artificial test patterns
326
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996
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