The image processing program presented was 
DIBIAS. Two systems were operational: one with 
raw data and the other with computer compatible 
tape. Emphasis had been on identifying changing 
phenomena. At the time, about 100 image pro- 
cessing programs (modular) were in use. 
The general discussion was opened by Mr. N. 
Donker (Netherlands) who asked what kind of 
colour display had been used and how hard 
copies were made. Dr. Kritikos described the 
printers used, all normal output devices. 
Mr. A. Jones (Australia) asked what sort of ac- 
curacies had been achieved with automated 
classification. Dr. Kritikos said he had rather 
limited experience and that the results depend 
on the type of object. He gave 80% as an average 
estimate. 
Author: Mr. W. Kreiling (F.R.G.) 
Title: Automatic Evaluation of Stereo- 
photographs by Digital Correlation 
PP 111/131 
Mr. Kreiling described an automatic digital 
restitution system for production of orthophoto- 
maps with contour lines. Equipment required 
consists of an image-scanner/printer and digital 
computer. Results show a height accuracy of 
0.4°%o of flying height for wellstructured areas. 
Authors: Dr. T. Keating (U.S.A.) 
Dr. P. Wolf (U.S.A.) 
Title: Analytical Photogrammetry from 
Digitized Image Densities PP ////30 
Dr. Keating described a digital analytical photo- 
grammetric system which can be used to develop 
a framework for land-oriented resource informa- 
tion systems. The framework consists of three- 
dimensional terrain coordinates, generated en- 
tirely within, and therefore compatible directly 
with, a general-purpose digital computer. 
Dr. O. Hofmann (F.R.G.) asked whether the same 
accuracy is obtained with a two-dimensional 
raster as with scanning in epipolar lines, the way 
Mr. U. Helava (U.S.A.) does it. Dr. Keating an- 
swered that Mr. Helava's method is certainly 
good, but costly. He added that his own system 
makes use of the same information as Mr. 
Helava's system, so the accuracy obtained is the 
same. Data processing requires much computing 
time, but the instruments are not too complicated. 
Mr. W. Kreiling (F.R.G.) said some kind of a com- 
promise should be reached between scanning in 
rasters and in epipolar lines. 
Dr. E. Mikhail (U.S.A.) asked how long it takes to 
scan a photograph with a 25 um resolution, and 
when an on-line laser scanner is used. He also 
said that one should not believe that a digital 
image could completely replace a photograph. 
Dr. Keating answered that the scanning of one 
photograph with a resolution of 100 um takes 
30 minutes, and consequently 16 times more 
time is required with a 25 um resolution. He 
said a laser scanner would reduce the time 
required to 1/10 or 1/20. He added that with a 
25 um resolution part of the information is lost, 
but this accuracy is sufficient for relative orien- 
tation. He said the costs were US $200 per pho- 
tograph. 
104 
Author: Dr. S. Wu (U.S.A.) 
Title: Stereomapping with the Viking 
Lander Camera Imagery PP 111/63 
Finally, a brief review of stereomapping with the 
Viking Lander imagery was presented. This 
presentation was timely in view of the subsequent 
landing of Viking Lander on Mars the next day, 
July 20, 1976. 
Dr. Wu presented the Viking Lander facsimile 
camera system and described the stereomapping 
of imagery produced by it. Photogrammetric 
problems arise from the fact that the imagery 
produced actually represents a portion of a 
spherical surface. 
Tuesday, July 20, 1976, from 10.45 to 12.15 
Session 7 of Commission lll 
Topic: Remote Sensing (1) Geometric 
Transformations of Scanner Imagery 
Chairman: Dr. K. Rinner (Austria) 
The following Presented Paper dealing with the 
topic of the session had been handed in, but 
there was not enough time for its full presenta- 
tion. 
Author: Dr. W. Schuhr (F.R.G.) 
Title: Digital Rectification of Multispectral 
Imagery PP 111/53 
Computer programs for digital rectification of 
multispectral scanner imagery for both methods, 
the direct and indirect type, have been developed. 
The changing of the exterior orientation elements 
with the time was expressed with first and second 
order polynomials and with spline functions. 
The first paper of the day was presented by 
Dr. G. Konecny (F.R.G.). 
Working Group Paper 
Author: Dr. G. Konecny (F.R.G.) 
Title: Report on Activities of Working 
Group "Geometry of Remote Sens- 
ing" WGR 111/102 
This report was a very comprehensive treatment 
of the working group activities and results ob- 
tained by participants using satellite and aircraft 
supported scanner imagery and radar imagery. 
In the general discussion Dr. O. Hofmann (F.R.G.) 
referred to opto-electronic scanners being de- 
veloped that are based on linear semi-conductive 
photosensors and that facilitate the analysis of 
remote sensing data. If, in addition to this, sta- 
bilized platforms are used — as was going to 
be done in the Spacelab — images with no 
distortion are obtained. 
Dr. Konecny said that the system presented by 
Dr. Hofmann simplifies the geometrical problems 
encountered in remote sensing. He added that 
accuracy could be improved by registering 
orientation parameters. 
Dr. F. Leber! (U.S.A.) said that photogrammetrists 
in general are not interested in stabilized plat- 
forms. He mentioned that plans had been made 
in the U.S.A. to send off Stereosat with two 
unstabilized scanners that are in a convergent 
angle of 60°. Dr. Konecny answered that stereo- 
satellites are interesting, but that they are not 
accurate enough for the mapping of the earth.