The 6 steps for MSS calibration are defined as follows 
STEP 1 : 
ACCUMULATE CAL WEDGE SAMPLES AND 
VIDEO HISTOGRAMS 
4 along track segments per scene 
STEP 2: 
PERFORM CAL WEDGE PROCESSING 
uses 6 samples from CAL wedge 
data to calculate radiometric 
transfer functions in the form 
of Radiometric Look Up Tables 
(RLUTS) 
STEP 3: 
PERFORM HISTOGRAM ADJUSTMENT 
- adjust RLUTS based on analysis 
of histograms 
STEP 4: 
BLEND SCENE SEGMENTS 
3 sub-segments per segment are 
used to smooth the transition 
STEP 5: 
GENERATE RADIOMETRIC CORRECTION 
LOOK-UP TABLES (RLUTS) 
data decompression and radio- 
metric correction are combined 
STEP 6: 
APPLY RLUTS TO DIGITAL IMAGERY AND 
GENERATE ARCHIVE TAPE 
CONCLUSIONS 
Landsat-4 continues the availability of Multispectral 
Scanner data to the user community with only relatively 
minor changes. Improvements in both flight and ground 
segments promise better geometric and radiometric per 
formance. The reliability and throughput capabilities 
designed into the ground segment will provide data to EDC 
in a timely fashion. The promise of the Thematic Mapper 
instrument is being evaluated as part of a NASA research 
and development program. 
ACKNOWLEDGEMENTS 
The author consulted with many specialists within both NASA 
and the General Electric Company during the preparation of 
this paper. Their advice and contributions are gratefully 
appreciated. 
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