SMSPEC may be used to smooth an ATRLUT-generated surface reflectance data set in the along-band dimension to reduce the effect of spectral line curvature (spikes near absorption feature wavelengths). This is a faster alternative to using GENCLUT, a CLUT with ATRLUT, and SLCCOR, but it is generally not as effective.
In addition to suppressing artifacts in the surface reflectance data set, smoothing with SMSPEC may also suppress important material diagnostic features in the band spectra. The more prominent the noise features and the greater the amount of smoothing specified, the greater this undesirable effect.
Even when spectral line curvature is detected and corrected using a CLUT, some artifacts may appear in the surface reflectance data set. These artifacts are usually small enough to be effectively suppressed with a small degree of smoothing that does not introduce a significant amount of distortion.
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