User Manual - pancroma

Note that the ASTER TIR bands are I16 format with a 14 bit dynamic range.PANCROMA TM uses the full available dynamic range in converting the DNs todegrees Kelvin. As with Landsat surface temperate computations, you can alsosave your color and grayscale image files, and also save the computedtemperatures in GeoTiff or flat binary format.WorldView 2 Top of Atmosphere ReflectancePANCROMA TM can compute WorldView2 TOA reflectances. Digital Globe callsthis procedure ‘calibration’.The calibration procedure is described in the Digital Globe publication entitledRadiometric Use of WorldView-2 Imagery available at the Digital Globe website.Quoting from this publication: "WorldView-2 products are delivered to thecustomer as radiometrically corrected image pixels. Their values are a function ofhow much spectral radiance enters the telescope aperture and the instrumentconversion of that radiation into a digital signal. That signal depends on thespectral transmission of the telescope and MS filters, the throughput of thetelescope, the spectral quantum efficiency of the detectors, and the analog todigital conversion. Therefore, image pixel data are unique to WorldView-2 andshould not be directly compared to imagery from other sensors in aradiometric/spectral sense. Instead, image pixels should be converted to top-ofatmospherespectral radiance at a minimum."195