Have you looked at the background information on Fast Line-of-sight Atmospheric Analysis of Hypercubes (FLAASH) & QUick Atmospheric Correction (QUAC) product documentation webpages? The differences are quite clearly described there.
Have you looked at the background information on Fast Line-of-sight Atmospheric Analysis of Hypercubes (FLAASH) & QUick Atmospheric Correction (QUAC) product documentation webpages? The differences are quite clearly described there.