EuroSDR Projects - Host Ireland

Figure 9 shows one example of image processing inputs and result for part of a built-up area analysis.
The reference data set is displayed on the left, the participant’s interpretation in the middle, and the
result of image subtraction is shown on the right hand side. Different colours in the resulting image
are defined as followed:
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• Black: Correctly interpreted areas
• Orange: False positively interpreted areas
• Yellow: False negatively interpreted areas
Correctly interpreted areas are those parts which were located in the interpreter’s image as well as in
the reference image. The parts which are defined as false positively interpreted are those areas which
were located by the interpreter but do not appear in the reference map of the corresponding object
class. And finally, the false negatively interpreted areas were located in the reference map but not
detected by the interpreter. Each object class layer of all interpreters was compared with the corresponding
layer of the reference data in this way.
Reference
image
Interpreter’s
image
Image processing
result
Figure 10: Image processing procedure
Wald - SAR
To achieve comparable information for the results, the number of pixels of reference content of each
object layer was set to 100%. Thus the number of pixels of false negatively interpreted areas (yellow)
and correctly interpreted areas (grey) will add-up to 100% in the resulting image. Those areas which
were false positively classified (orange) by the interpreter were added as percentage values above
100% (Figure 10).
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Result
Int 1 Int 3 Int 5 Int 8 Int 10