I have an 8 band WorldView-3 multispectral image. I am trying to process it to surface reflectance using ENVI. The trouble is I keep getting strong negative values of the reflectance, with no data areas rendered in bright blue, probably due to colour stretching.

My procedure is:

1. Import WV3 .TIL file. This imports metadata such as FWHM, gains and offsets.
2. Resize (clip) the raster to remove no data values around the edge of the image.
3. Use the radiometric calibration tool with the "Apply FLAASH settings" button to convert to TOA radiance. This turns (0,0,0) values into (No Data, No Data, No Data) values.
4. Use the FLAASH tool to apply FLAASH. Aerosol retrieval is turned off, due to there being no appropriate band for the upper KT channel in the 8 band WV3 data. Also, water retrieval is automatically turned off when the radiance file is imported to the FLAASH tool.

The FLAASH tool produces many strongly negative reflectance values. I think this may be due to the way No Data values are handled in the toolchain. The original (clipped, DNs) image has no (0,0,0) or No Data values. The radiometric correction tool produces many No Data values on rivers and lakes (as per image), resulting from conversion of low (but not zero) DNs. FLAASH then converts these values to (0,0,0) and pushes other image data strongly negative.

My guess is that I need to get these No Data values handled correctly, but I don't know how to do it. I have tried editing the image metadata to set a Data Ignore value to 0, or -9999, or just removed the Data Ignore metadata value entirely, every combination I could think of, but nothing works. Does anyone work with WV3 in ENVI and have a solution?