How to convert ASTER VNIR Radiance to Reflectance

ENVI automatically applies the proper calibration coefficients to convert the integer digital numbers to floating-point radiance values when opening a Level 1B or 1T dataset.  You can easily convert these values to Top-Of-Atmosphere Reflectance in ENVI.  From the Toolbox select Radiometric Correction | Radiometric Calibration and select the three-band VNIR file.  Change the Calibration Type to Reflectance, enter a new filename, and click OK.