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EXPERIENCES IN PROCESSING MOMS-02/D2 STEREO IMAGE DATA 
Dieter Fritsch, Michael Hahn, Franz Schneider, Dirk Stallmann, Michael Kiefner 
Institute of Photogrammetry 
Stuttgart University 
P.O.B. 106037 
70049 Stuttgart / Germany 
ISPRS Commission IV, Working Group 2 
KEY WORDS: Digital Terrain Model, GPS profile, accuracy analysis, three-line images, MOMS-02/D2, along- 
track stereo 
ABSTRACT 
The first experiences of the German MOMS research groups in processing MOMS-02/D2 stereo image data 
have been presented at a MOMS workshop in Cologne in 1995. Focus was on the evaluation of the photogram- 
metric processes of point transfer, line-image orientation, point determination, DTM acquisition, ortho-image 
generation and topographic mapping. The accuracy level for geometric 3-D reconstruction achieved in those 
work was of 6 to 10 meter for the horizontal coordinates and 7 to 15 meter for the height. 
This paper presents new experimental results of our ongoing work in automatic 3D point determination and 
DTM generation using MOMS three-line stereo images. Our interest is in the verification and exact assessment 
of precision and reliability of photogrammetric processes. Therefore, we focus the investigation on images 
taken over a testfield in Australia for which a GPS network of image identifiable control points and, additionally, 
a 3-D profile of about 16 km length is surveyed. This GPS profile is resolved with a 5 m spacing interval that 
delivers 3228 DTM check points. 
For the first time we have now been able to proof that DTM and 3-D point determination with MOMS data is 
possible at an accuracy level better than 5 m. Comparison with the dense ground truth profile shows that in 
our feature based DTM solution an accuracy of 7.6 m is obtained. A further improvement could be achieved 
with an area based least squares solution for MOMS three-line images, which increases the precision of the 
height, again verified along the GPS profile, to 4.3 m. 
1. INTRODUCTION with the three panchromatic CCD line images. In this 
case image data are taken with 4.5 m pixel size by 
the nadir looking channel and with 13.5 m pixel size 
by the forward and backward looking channels. An- 
other mode of interest for stereo restitution is mode 3 
in which a combination of two panchromatic and two 
multispectral channels is selected. The multispectral 
channels are all nadir looking thus two of them are 
used to substitute the panchromatic nadir channel. 
Together with the two off-nadir channels a similar ge- 
ometric configuration exists as in the mode 1 case. 
Following up the German Spacelab D2 Mission in 
April 1993, in which MOMS-02 imagery over parts of 
Africa, Asia, Middle East, South and Central Amer- 
ica, and Australia have been recorded, a consider- 
able number of investigations has been carried out 
with the multispectral and panchromatic image data. 
The primary interest of the photogrammetric commu- 
nity is in the potential of the high resolution three-line 
stereo images for generation of Digital Terrain Models 
and ortho-images as well as topographic data collec- 
tion. 
The MOMS-02 camera is designed with seven chan- 
nels which can be operated in different modes. For 
topographic applications mode 1 is most important 
267 
For several years the Institute of Photogrammetry of 
Stuttgart University is developing procedures for re- 
liable and precise point transfer, 3-D point measure- 
ment, DTM acquisition and ortho-image generation. 
Further tasks and the overall scientific objective of 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996