Geometric Analysis and Correction of Threefold Stereoscopio
Linescanner Images for MEOSS Project
A. Drescher, Poject Scientist
DFVLR, German Aerospace Establishment
institute for Optoelectronics
D-8031 Oberpfaffenhofen, FRG
Abstract
MEOSS, an experimental threefold stereoscopic CCD linescan
camera of DFVLR will be flown by ISRO on her SROSS-satel-
lite in 1987. :
The MEOSS camera will sequentially generate three image
stripes of the earth surface from the same orbit. Orbit and
attitude variations of the satellite generate correlated
geometric distortions in those image stripes.
To correct this distortions DEVLR will apply a distortion
model based on photogrammetric colinearity equations and a
parametric formulation of satellite dynamics.
Principles and procedures that will be applied for-geome-
tric analysis, correction and evaluation of the threefold
stereoscopic linescan images are presented. Special empha-
sis is given on deviations from standard procedures applied
in airborne photogrammetry,
Introduction
MEOSS will be the first 3fold stereoscopic linescanner in
Space. The basic principle was developed by earlier mission
proposals STEREOSAT [1], MAPSAT |2| and Stereo-MOMS I3] as
an optoelectronic alternative to photographic frame
cameras.
In the MEOSS camera the three image stripes are generated
by three parallel linear CCD arrays on the focal plane of a
single optics. The earth rotation effect is compensated by
an electronic shift of the active regions of the linear CCD
arrays and not by yaw control of the camera or the whole
satellite, Thus tilting of the scanlines with respect to
the orbital axis can be avoided fig. 4.
Apparently it is very demanding to ensure geometric fideli-
ty for stereoscopic linescan images by active attitude con-
trol of a satellite (STEREOSAT |4|, MAPSAT |5|). Following
a suggestion first formulated by Dr. O. Hofmann of MBB for
Stereo MOMS, ISRO and DFVLR will concentrate their efforts
not on the avoidance of geometric image distortions, but on
their proper analysis and correction.
200
|
Ss On SOT NTH Q o uou'ódcdcdcco—uncru
cr E 53 *yY cJ O (i).cCc c +43
LE 0C 3 n rho rn 'T
