EFFECTS OF ANALOG-TO-DIGITAL CONVERSION ON REPRESENTATIVE PROPERTIES OF SPACE PHOTOGRAPHS

Two Russian remote sensing specialists examine the effects of analog-to-digital conversion of space photographs (i.e., the changes in information representation resulting from the digitization of photographic originals). One of the most important changes is a decrease in tone contrast relative to the original photoimages, which they assess using a modulation transfer function. They attempt to determine how much cartographic information is lost through such conversion, by revising a 1:25,000-scale topographic map on the basis of digitized space photographs.