User Manual - pancroma

23. Pan Sharpening Interpolation Methods________________________________________________________________Interpolation is a key part of the pan sharpening process. Regardless of themethod, at some point the row and column counts of the multispectral band files(or transformed multispectral band files) must be forced to match that of thepanchromatic band. This is typically done in a two-step process. In the firststep, the multispectral band files are resampled, i.e. expanded to create a sparseimage. In the case of Landsat, for example, the rows are expanded so that thereis an original band pixel at every other pixel location along the rows, with a ‘nodata’ (actually zero value) pixel in between. Moreover, these rows exist at onlyevery other row location. The result is a sparse data file containing 25% originalband file data and 75% missing data. The missing data is replaced with colorinformation interpolated from the original data in the second step.PANCROMA TM normally uses a proprietary bicubic/Laplacian non-iterativeinterpolation algorithm for pan sharpening as its default method. This method isspecially designed for data sets where the size of the panchromatic file is 2X thesize of the multispectral bands.PANCROMA TM offers alternative interpolation methods as well. Checking the‘Activate Image Processing Routines’ checkbox on the main menu will displaythe Image Processing Data Box during processing. The lower left had cornercontains the Interpolation Group.52