= 695 - 
THE MULTISPECTRAL SCANNER AS A RESEARCH TOOL FOR SIGNATURE 
MEASUREMENTS 
By 
P.G. Reichert 
Abteilung Luftbildmessung und Luftbildinterpretation der 
Universität Freiburg, Federal Republic of Germany 
ABSTRACT: The identification of objects in multispectral remotely 
sensed data presupposes an understanding of the spectral behaviour 
of the surfaces of these objects. The determination of reflexion 
properties in situ requires a high amount of technical install- 
ments, and, because of the limited mobility of the instruments 
involved, allows for the measurement of only a few objects per 
suitable day of measurement. In the following paper, the multi- 
spectral scanner will be presented as an instrument which 
supplies a large number of measurements of different surface 
types within a very short time, thereby making possible the 
systematic investigation of various objects under various eco- 
logical but constant atmospheric conditions. Finally, some represen- 
tative examples gained from MSS signature graphs will be given. 
1. Introduction: Remote Sensing Techniques, working in the visible 
and near infrared parts of the electromagnetic spectrum, use for 
the identification of objects their characteristic spectral 
reflection behaviour. But it should be pointed out that the 
spectral signatures of different vegetation types are not only 
dependent on the vegetation species themselves but also on 
changes due to the phenological stage, vigor conditions, a large 
number of ecological and man-induced factors, as well as 
irridiation and observation angles. In order to analyse and 
quantify - and possibly correct - the influence of the above mentioned 
factors we need a very large number of measurements of different 
vegetation types under different conditions and from different 
observation angles. 
In the past, mostly laboratory measurements of flatlying plant 
leaves have been done (1), thus neglecting the influence of the 
canopy structure, site, vigor and weather conditions etc., which 
can only be measured in the field. Field measurements of the 
spectral signatures of vegetation covers, which have been performed 
during the last years by different European institutions, have led 
so far to relatively few measurements because of the unfavourable 
weather conditions in middle Europe and the limited mobility of 
the field measurement installments. 
Therefore it was necessary to find an instrument which allows 
the acquéition of a high rate of measurement within a short 
period. The Multispectral Scanner Bendix M^S has proved to be 
an excellent instrument for such measurements, delivering more 
than 2 million signature curves per minute of operation.