User Manual - pancroma

Channel Level AdjustPANCROMA TM provides two types of channel adjustment. Modifying the colorbalance by adjusting the band files as described in the previous section affectsthe color of the input bands. A second set of channel adjustments is provided forbalancing the channels of the output bands after the reverse transformation.Since the fidelity of the transformation and reverse transformation is good, theseadjustments are equivalent for the most part. Post processing adjustments areexact but more computationally expensive while pre processing iscomputationally cheaper but may suffer a slight loss of fidelity due totransformation rounding errors. The adjustment can be made by checking the‘Enable Channel Level Adjust’ check box and adjusting the red, green and blueslider bars.Pan Channel LevelThis utility allows the panchromatic image to be adjusted by adding or subtractinga specified value from each of the pixels in the panchromatic image. The ‘EnablePan File Adjust’ check box activates a slider that allows the PAN file pixels to beadjusted up or down. This is sometimes useful to increase the ‘blueness’ ofwater coverage since the PAN sensor does not detect radiation reflected fromwater very well. Although increasing all panchromatic values will often make theocean bluer, it will unfortunately make forested areas too blue as well.Merge Intensity ArrayThis utility attempts to use the color information in the computed intensity arrayrather than to ignore or discard it. This color information in the computedintensity array is arithmetically combined with that in the panchromatic array toproduce a higher fidelity panchromatic image. The ‘Merge Intensity Array’feature replaces panchromatic file pixels with the corresponding pixels from theintensity array computed from the RGB bands. Since there are only ¼ as manyintensity pixels than panchromatic pixels, the result is a kind of gridded imagewhere 25% of the pixels are “true” color (as if from the RGB image) and theremaining 75% are uncorrected panchromatic pixels.PANCROMA TM provides a utility for interpolating between the intensity pixels andthe panchromatic pixels, and is accomplished by selecting the ‘InterpolateIntensity Array’ check box. (Note: if you intend to select this feature you must setthe number of interpolation iterations in the dialog box that is presentedimmediately after loading the band and panchromatic images. If you do not it willuse the default 10 iterations.This approach is only marginally beneficial. Interpolating color information workswell but interpolating image information works much less so as the latter diffuses164