4.1.4 PHIDIAS 
In addition to the . standard hardware as 
described in chapter one, the PHIDIAS system 
[BENNING, EFFKEMANN 1990] consists of a 
scanner, and the personal computer needs 2MB 
RAM and a 150 MB hard disk. It uses digitized 
images. The analogous images are scanned with a 
300 dpi flat-bed-scanner. Software for the 
calculation of the réseau correction to 
compensate image deformation is available. The 
orientation parameters and coordinates are 
calculated with the bundle adjustment. Two 
photos are used for the  monoscopic image 
evaluation, and the coordinates of the measured 
points are calculated with spatial 
intersection. If the user is working with plane 
areas a single image solution is possible. The 
measurements are displayed on the screen by 
superimpositioning of vectors. 
4.1.5 PhotoCAD 
PhotoCAD allows the compensation of image 
deformation by calculating the réseau 
correction. The system offers a two image 
solution, which means that no bundle adjustment 
is computed. Therefore the used camera has to 
be calibrated in advance. After the numerical 
orientation process the evaluation of the 
object is done with two images. It is supported 
by graphical functions and can be viewed on the 
monitor. À single image evaluation is possible 
as well. 
4.1.6 Comparision of Systems with 
Monoscopic Image Measurement 
One of the main characteristic of the systems 
described above is the use of photos which are 
not limited to the normal case of stereo 
photogrammetry. MR2, PHIDIAS, and Elcovision 
use the bundle  adjustement method for a 
simultaneous calculation of the orientation 
parameters, and Foto 3D computes all parameters 
using the projective approach, requiring three 
dimensional control points. Only  MR2 and 
PHIDIAS allow simultaneous self calibration of 
the camera. Due to the simultaneous calculation 
of all parameters the overall accuracy of the 
     
final evaluation is significantly increased. 
All systems work with standard personal 
computer hardware, but PHIDIAS needs 2 MB RAM, 
a 150 MB hard disk, and a 16 inch or larger 
monitor. In table 4.1.1 the above mentioned 
systems are listed in alphabetical order with 
some important characteristics. The prices are 
software prices. All additional hardware is of 
extra cost. 
4.2 Systems with Stereoscopic Image 
Measurement 
4.2.1 Alpha 2000 
The Alpha 2000 belongs to the categorie of 
object-space-plotters and works in connection 
with two IBM compatible 386/25 personal 
computers. The first is used as a system unit 
with the control, calibration, and orientation 
software. The second, which needs 8 MB RAM and 
a 210 MB hard disk, works as application 
computer. An optional superimposition module 
provides the capability to overlay digitzed 
data on the visual photographic stereo model. 
Furthermore there are some software options for 
application and data compilation tasks 
available. 
4.2.2 ASP 2000 
The ASP 2000 is considered to be portable. The 
systems provides a method of measuring lens 
distortion and calculating radial and 
tangential parameters. The exterior orientation 
is calculated using a bundle adjustment from up 
to 12 points. During the digitizing process the 
collected data is displayed on a colour 
monitor. 
4.2.3 DVP 
The 
CAGNON, AGNARD 1992] uses digitized 
images instead of film it. The 
done with conventional desktop 
scanners (resolution: up to 600 dpi). 
stereo images are displayed on the screen. 
(Digital 
Video 
  
  
  
  
  
  
  
  
  
  
  
  
Price Resol. addit. Interf. Simult. 
[1000 of meas. observ. to CAD camera 
US $] system in Obj. Systems calibr. 
[um] Space possible 
Elcovision 10-15 25 yes yes no 
Foto 3D 5-10 25 no yes - 
MR2 10-15 25 yes yes yes 
PHIDIAS 15-20 25 yes yes yes 
PhotoCAD 5-10 20 yes yes no 
  
Table 4.1.1 Systems with monoscopic 
image measurement 
Plotter)