Hello, If you used the Radiometric Calibration tool to create a radiance image for input into FLAASH, leave the default value of 1 for the Single Scale Factor field of the Radiance Scale Factors dialog. ENVI has already applied the correct scale factor needed to get the image into units of µW/(cm2 * sr * nm). You don't need to refer to a separate ASCII file. The Radiometric Calibration tool can calibrate the WV-2 image to top-of-atmosphere reflectance. However, to perform a true atmospheric correction (to surface reflectance), you'll need to use FLAASH or even QUAC. I would suggest that you try QUAC; however you will need to first mask out any ocean or background pixels.

You can try the QUAC atmospheric correction tool. It requires less parameter setting, and so is sometimes much easier to get to run without errors. It sounds like your WV2 image that comes out of the radiometric calibration has lost the wavelengths values associated with each band. This is a known issue in ENVI version 5.0. It was fixed with the second service pack to ENVI 5.0. So if you have the ability to upgrade to a more recent version of ENVI (the current version is 5.3), then this problem should go away. Otherwise, you will need to use the Edit ENVI Header file to add the center wavelength for each WV2 band back into the header before using the file as input to FLAASH. - Peg