| Re: Help requested - Spectral Resampling Problem in ENVI [message #20358] |
Thu, 08 June 2000 00:00 |
cjengo
Messages: 28
Registered: June 1999
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Junior Member |
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If your custom classifier is written in IDL, you should use the
envi_select procedure which will let you do spectral (and spatial, plus
any masking) subsetting on the fly. Just keep track of the pos and
dims keywords, and use envi_file_query to put your wavelengths into an
array. If you'd rather set-up the files beforehand, do Utilities>File
Utilities>Resize Images(Spatial/Spectral) to extract the 10 bands from
the 48 in the image. You really don't need to resample the spectral
library, as it has the same wavelengths of the image. You could just
extract the 10 bands you want (spectral libraries are just 2D arrays,
where spectral samples are columns and materials are rows). Or just
use the Spectral Resampling you described above and use your newly
subsetted data file as the wavelength reference.
Hope this helps...
BTW, if you use ENVI's endmember selection tool (envi_collect_spectra),
it will take care of spectral library resampling for you based upon the
wavelengths of your input data.
Chris
_______________________________________
Chris Jengo - Senior Imaging Scientist
Earth Satellite Corp. - Rockville, MD
Sent via Deja.com http://www.deja.com/
Before you buy.
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