So far, only signature curves based on the means of the 
reflectance factors have been shown. However, a variation of 
the reflectance of even the same object which can be caused by 
a large number of factors can be expected (11). This variance 
seems to be very high in the near IR (figure 10) but this should be 
proved by comparing the coefficients of variation. 
It becomes clear, however, in figure 11 that the coefficients 
are not considerably higher in the near IR compared with those 
in the visible part of the spectrum. Nevertheless, a drastic 
change of the coefficients can be observed for a mature beech 
stand. This is due to the fact that the crown size of these 
beeches could not be integrated by the instantaneous field of 
view, which is to say, the light and shadow-patterns of the 2 
individual crowns cannot be integrated by the IFOV of 2 x 2 m*. 
In addition, the shadow patterns of the crowns are not brightened 
by the scattering light as it is the case in the visible part of 
the spectrum. 
High variances of the reflectance factors make it difficult to 
recognize objects because of their reflection behaviour. As shown 
in figure 12 this variance can be largely reduced by selecting 
a suitable ground resolution which can be obtained either by 
smocthing the pixels of the imagery considered or by using a 
higher flight level. 
Since it is not possible to compare several hundred signatures 
standardized as described in this paper but each of them obtained 
under different conditions we need a data management system which 
enables us to work with a large quantity of data. Such a data 
bank management system is going to be established at the computer 
center of the University of Freiburg. 
Literatur Cited 
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/2/ Modular Multispectral Scanner (vas) Folder I Technical Proposals, Ann- 
Arbor, Michigan, April 1974 
/3/ H.J. Boehnel: Bestimmung spektraler Signaturen von bewachsenen Oberflächen 
durch radiometrische Bodenmessungen (Realisierung und Probleme) *) 
/4/ Fischer W.: Zur Signifikanz von spektralen Signaturen bewachsener Ober- 
flüchen im Bereich 4oo - 1100 Nanameter +) 
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während der Vegetationsperiode *) 
/6/ Reichert P.G.: Der Multispektralscanner als Instrument der Signaturforschung +) 
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raturen (nicht veróffentlich) 
/8/ Schrüder, M.: Ziele und Aufgaben des FlugzeugmeBprogrammes +) 
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/1o/ StátterR.: Einflu8 radiometrischer Parameter auf Fernerkundungsaufnahmen *) 
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und forstwirtschaftliche Inventuren. * 
*) Forschungsbericht W 78-04 des BM für Forschung und Technologie, 1978