18 
INTRODUCTION It is 
fixed 
. . ... From c 
The images used for processing and analysis are b/w positive transparencies displa 
in the size 6 cm x 6 cm, delivered from the NASA. Other material and 
formats were not available, the use of CCT is not yet possible. The Detail 
quality of these pictures is not very good, so a preprocessing of the f or \ E 
pictures with the colour scanner was made. The pictures are enlarged to the inforn 
scale 1 : 1 Million, 1 : 400 000 and 1 : 200 000. The colour scanner The 
allows the enlargement up to 20 times with corrections of the density Q f 0 bj 
and gradation. The enlargement scale is adjusted slightly for the different are a ^ 
MSS channels, so they fit exactly for color compositions. 
The enlarged, corrected b/w positive tranparencies are used for further 
treatment, picture analysis and to compose colour transparencies. 
For machine processing a scale of 1 : 1 million suffices. The scanning 
resolution of the machine is 40 lines/mm. This gives a theoretical ground The sc 
resolution of 25 m . For visual evaluation some parts of the pictures densit 
are enlarged to a scale 1 : 100 000. dark t 
separa 
Aerial photographs are made with a Hasselblad camera on 70 mm colour ponds 
reversal and ir-colour film. These pictures are mainly used for a of the 
discrimination of agricultural vegetation and plant damages by a are de 
combination of spectral signature and spatial texture analysis. resolt 
high p 
outlie 
in the 
OPERATIONS values 
areas 
The procedures carried out for picture processing may be classified The sa 
in global, local and point operations. colour 
water 
Global operations change the whole picture, like rectification, enlarge 
ment, transformation. They are used here only for preprocessing the For gr 
b/w MSS images. can be 
water 
The local operations are related to the information of the picture down t 
element and a small area around it. These are mainly used for pattern 
and texture analysis. Investigations are made to modify the signal by For ve 
active electronic filters changing the modulation transfer function colour 
and analyzing the spatial frequency spectrum. This method is applied to Normal 
the classification of agricultural vegetation using aerial photographs, with g 
the application on ERTS imagery is planned. a two- 
For ve 
The most applicable operations for ERTS imagery are point operations shows 
for spectral signature analysis. There are different methods used for 
land use and vegetation mapping. The point operations are carried out Before 
by the electronic comparison of the three colour density signals in scanne 
the colour computer or the manipulation of the density signal from object 
one spectral band b/w picture. represi