Sovremennye problemy distantsionnogo zondirovaniya Zemli iz kosmosa, 2010, Vol. 7, No. 2, pp. 14-25
Estimation of Efficiency of Algorithms for Synthesizing the Aperture
of Scanning Radiometer
V.I. Gornyy
1, M.I. Kislitskij
2, I.Sh. Latypov
11 Scientific Research Center for Ecological Safety, Russian Academy of Sciences, 18, Korpusnaya Str., Saint-Petersburg, 197110, Russia
2 FSUE Arsenal Design Bureau named after M. V. Frunze
FEDERAL SPACE AGENCY, 1-3, Komsomola Str., Saint-Petersburg, 195009, Russia
More and more rigorous requirements concerning the spatial resolution and repeatedness of survey are imposed on
remote sensing (RS) of the Earth from space by passive scanning radiometers (scanners). The high spatial resolution
is achieved by using expensive long-focus objectives with a wide aperture, although the angle of view decreases in
this case. Therefore, the necessary repeatedness of observations is provided by an increase in the number of satellites
or by targeting surveys with the help of rotatable mirrors and platforms, resulting in a high cost of space RS
systems. Thus, the simultaneous requirement of high spatial resolution and a wide view strip is contradictory.
A similar problem existed during the development of side-looking airborne radars. Antennas with linear sizes exceeding
those of planes were needed to obtain high spatial resolution with a wide view strip. The problem was
solved by the creation of synthetic aperture radars (SAR) [2].
The improving resolution for the optical-electronic RS systems is based on the ill-posed problem of image deconvolution
with help of point spread function of device.
With the aim to estimate the solution stability for the geometry of scanning distortion due to the satellite evolution
we have investigated the effectiveness of different algorithms of aperture sintesizing: - deconvolution by solving the
system of inequalities; - van Cittert algorithm; - algorithm.
In the framework of digital experiment we have shown that algorithm of van Cittert and Gold do not depend practically
on distortion of scanning geometry. But, opposite to algorithm of deconvolution by solving the system of inequalities,
algorithms of van Cittert and Gold do not restore the necessary resolution.
Keywords: digital image processing, subpixel scanning, space images
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