Improving AVHRR resolution through data cumulation for mapping polar ice sheets

Data cumulation ir a digital image processing technique in which several scenes of the same area, taken under similar viewing-conditions; are ca combined into a single image of enhanced spatial and radiometric resolution, This is effected by the reduction of aliasing in the along-scan and along-track sampling of scenes, and by the reduction of noise content in the combined scene, The technique hinges on two key steps: accurate image coregistration to a precision significantly better than I pixel; and cumulation of multiple image data grids (derived from the individual images) into a single image. We report here on the development and initial results of the application of data cumulation using Advanced Very High Resolution Radiometer (AVHRR) satellite images of the polar ice sheets. The process can improve the real spatial resolution of AVHRR data in the along-scan direction from 1000 m to 650 m,and in the along-track direction from 1400 m to 700 m, justifying a decrease in pixel size to about 500 nz. The technique is demonstrated in art image of a portion of the Ross Ice Shelf in Antarctica. (C) Elsevier Science Inc.