The Auk can be configured to calculate a vegetation index for each image as the image is acquired. The kind of index (or indices; there can be more than one) is specified in the indices.txt file. It can take a several seconds to complete the processing for each image at full resolution: The lens is corrected for vignette effects, the false color RGB is calculated, and after that the band ratio calculations are performed. To speed things up, the user can specify reduced size output images. The scaling is done in powers of two; 1/2, 1/4, 1/8, etc.

0 = Extractions disabled
1 = Perform Full Res Extractions
2 = Perform half size Extractions
3 = Perform qtr size Extractions
4 = Perform eigth size Extractions
5 = Perform 1/16 size Extractions
6 = Perform 1/32 size Extractions
7 = Perform 1/64 size Extractions
8 = Perform 1/128 size Extractions