Scanning by means of a co 1 our-scanner 
Filling of reference areas at an image 
processing system. 
Extraction of a certain object quality; 
the result is a binary matrix of a certain 
pattern in which you can start a contour 
following algorithm. 
Calculation of axis coordinates by means 
of the extracted contours of a certain 
object (vector data processing) or extrac 
tion of axis coordinates after a topolo 
gical skeleton process (raster data 
processing). 
Figure 1 : 
Steps of process on the recognition of area 
contours, area qualities and axis coordinates 
A fast check of the boundary lines of the areas as to gaps 
is advisable in case the system does not eliminate such 
gaps automatically. An interactive correction with the aid 
of an image processing system is very time-consuming, so 
author prefer a proposal of the printing industry which 
has many experiences in the applications of co 1our-scanners 
and digital image processing systems for the reproduction 
of coloured graphics. We put the film original on an over 
head-projector and make a projection of it on the screen. 
In the projection we controll the graphic to undesired gaps 
and close them with ink on the original manually. That's a 
very fast and cheep manual process. 
In an experiment made with a sheet of the German Basic Map 
at the scale 1:5,000 (format 50 cm x 50 cm) of average 
representation density the manual colour encoding and the 
closing or elimination of gaps in lines took about 45 
minutes.