International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004 
The hardware configuration is shown in Figure 4. The ASCOT 
sends a trigger pulse through the Camera Controller (a 3-GHz 
computer with 500 MB of RAM and two 68-GB removable 
hard-drives) to the DFC. The DFC triggers a picture and sends a 
signal to the ASCOT and the POS, simultaneously, using 
precise time to relate each photo with the position and 
orientation of the acquisition platform at the time of exposure. 
All data is stored on the Camera Controller where the OPPP 
resides. The OPPP processing is conducted on the Camera 
Controller and output products are stored on one of the 
removable hard drives. 
Ascot 
    
10 Carl COM! 
Digital 
Frame 
Camera 
   
  
Digital 
Interface 
A 
  
  
ETIP, 
INO 
COMI 
f: OPPTP Output 
  
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Camera Controller 
Figure 4. Hardware integration of the OPPP with the DFC, 
POS, and ASCOT. 
Figure 5 is the integrated RTPMS as designed for installation in 
a B-200 fixed-wing aircraft. The figure shows the 4k x 4k 
digital camera mounted together with an Initial Measurement 
Unit (IMU) on a PAV-20 mount for the RC-30 camera base. 
The electronics rack holds the camera and the POS controllers. 
  
Figure 5 Integrated RTPMS consisting of a DFC, POS, PAV-20 
mount and a computer with the OPPP software. 
64 
  
Test Results of OPPP Software 
The newly developed OPPP has been successfully tested with 
both scanned aerial photography from an RC-30 film camera 
and DID from a DFC. Using scanned DID from RC-30 
photographs, a single strip of five images (4 models) and a 
block of three strips of 15 images (12 models) were tested. 
Together with orientation data from the POS, and without 
ground control or operator intervention, the OPPP produced a 
mosaicked DEM, ortho-image map, and contour map. Figure 6 
shows the contour map generated for the three-strip block. On a 
laptop computer, processing of the single strip of four models 
took 12 minutes and the processing of the block of three strips 
of 12 models completed in 42 minutes. 
  
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zure 6. Contour map generated from a block of three strips 
with 15 images. Contour interval is 1 meter. 
Aerial photographs were taken at a calibration range by an RC- 
30 camera (6-inch lens) with a POS device at a flight height of 
3,000 feet above ground level. The ground-targeted control 
points within the calibration range have a 2-cm relative 
precision and a 25-cm accuracy relative to the WGS-84 
Geodetic reference system. The POS has a precision of 20 arc 
seconds for the roll and pitch, and 30 arc seconds for the yaw. 
A total of 13 ground-control points of the calibration range 
were within the area encompassed by the single strip test. 
Results from the 13 ground control points are given in Table 1. 
  
  
Ground Coordinates (in cm) X Y Height 
Arithmetic Mean Error -&6  -17.7 -6.0 
Absolute Mean Error 10.2 17.7 12.2 
RMS Error 9.8 9.6 16.1 
  
Table 1. Comparison of processed data from a single strip with 
13 target points on the calibration range. 
For the three-strip test, 36 ground-control points measured on 
the OPPP-generated DEM were compared with the 
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