Quality Analysis of Multispectral Sensor Array Scanner Data 
B.~S. Schulz 
A Report from the Institute for Applied Geodesy, Frankfurt aM. 
Introduction 
The frequently unsatisfactory discrimination of land cover types obtained 
through procedures of classification of their multispectral characteris- 
tics, the problems likely to occur with transferring the class parameters 
defined for one area to a neighboring area, the question of data homoge- 
neity within homogenous land-cover areas and the resulting permissible 
expansion of the area to be classified - which may happen to be dependent 
upon predefinable measures of precision - give rise to a search for cri- 
teria and methods for the assessment of data set accuracy. 
Especially with sensor array scanners it must be taken into account that 
the sensors contributing to the aggregate recording show various determi- 
nistic and stochastic properties so that the requirement for homogeneity 
- provided that the sensor properties are stable - is only satisfied for 
the data subset associated with individual sensors, and not for the aggre- 
gate recording over all sensors. 
As a method of verification of the data inhomogenity caused by the indivi- 
dual sensors of a sensor array, the comparison of test values suggests 
itself. These have to be computed for each sensor-specific data subset 
derived from the given test areas. Sensor-dependent variations of the test 
values can eventually serve as a measure of accuracy for the functions to 
be derived. 
1. Data Selection 
In order to keep the number of sensor-specific subsets suitably small, the 
test values sufficiently accurate, even with smaller given test areas, and 
to permit comparison of sensor-specific test values from smaller adjacent 
test areas, the number of individual sensors defining a sensor array must 
be restricted to only a few. Under this aspect, the multispectral record- 
ings of LANDSAT, with 6 sensors per array (special band), seem appropriate 
for the following investigations. 
Conditioned by the LANDSAT-typical scan (simultaneous recording, at right 
angles to the satellite motion, of 6 sensor-assigned Scan lines per spectral 
band) the data subsets S. relating to the individual sensor i are produced 
channelwise as follows: 'S, results from lines 1, 7, 13, «S4, from lines 
2, 8, 14, ...»ete. , S, flom lines 6, 12, 18, ... of the original scan. 
The data sets 3: thus created 
- refer to a common area 
- contain an equal number of pixels 
- are staggered one scan line to each other, and 
- are therefore expected to differ only randomly, provided the number of 
lines and the area size for the scanned land cover types are sufficiently 
large [4]. 
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