Subtle contrasts and low radiances observed by the ERTS multispectral scanner over the ocean require computer enhancement for adequate analysis. Experiments designed to evaluate contrast stretching, ratioing, differencing, smoothing, filtering, and false-color enhancing, indicate that the best information can be extracted by simple contrast stretching. Spectral analysis of the data shows that a low-pass, two-dimensional filter kernel, designed to be 6 db down at 10 scanspots, effectively eliminates the six-line banding caused by the multispectral scanner design. Automatic contouring techniques require careful scrutiny because data fields are created which can lead to false interpretations. Joint histograms of oceanic radiances did not prove to be useful due to the low range of energy in the several spectral intervals. Comparisons of satellite data with surface ship observations confirm theoretical predictions of the difficulty in interpreting scenes of the coastal zone.
Computer enhancement of ERTS-1 images for ocean radiances
Vergroesserung von ERTS-1 Bildern durch Rechner fuer Meeresstrahlen
Remote Sensing of Environment ; 3 , 4 ; 237-253
1974
, 12 Quellen
Article (Journal)
English
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