Hello, I'm trying to make a radiometric correction of a Geoeye-1 image using ENVI 4.8 and FLAASH. Due to the lack of an automatic method to transform Digital Values to Radiance, I want to do it by myself applying the formula: Lλ = Gainλ *DNλ + Offsetλ where λ is Specific spectral band of image: Near-IR, Red, Green, Blue or Panchromatic.; Lλ is Spectral radiance for band λ at the sensor’s aperture (mW/cm2/μm/str); Gainλ is the Radiometric calibration gain (mW/cm2/μm/str/DN) for band λ from product metadata; DNλ is Digital number values for band λ of image product; and Offsetλ is Radiometric calibration offset (mW/cm2/μm/str) for band λ from product metadata. Is this equivalent to the usual formula Lλ = absCalFactor * Dnλ applied to other satellites/devices, i.e QuickBird? If it is so, do i still need to divide the result by the Effective Bandwith ?λ to reach the Top-of-Atmosphere Radiance which FLAASH demand as input? Thanks in advance