Numerical reduction techniques for large-dimension (10,000 x 10,000-pixel) astronomical images obtained by microdensitometer scanning of photographic plates are described and demonstrated. Consideration is given to the calibration procedure, smoothing algorithms and other noise-reduction methods, image stacking, search algorithms for object detection, photometric analysis, and star-galaxy
... [Show full abstract] separation. The catalogs produced by the reduction include positions with accuracy about 0.3 arcsec, classification and morphological data, magnitudes within a number of apertures, and multiple listings when data from different wavelength bands or at different epochs are analyzed. Diagrams, graphs, and sample contour maps are provided.