Two-Dimensional Logical Transforms
Cellular array transforms were first employed many years ago to perform “noise cleaning” operations on the input images of character recognition machines (Chapter 1). These transforms operated upon the bilevel or “binary” input generated by the character image digitizer and were designed to remove “salt and pepper” noise in the image of the character being read by the machine. By so doing the transforms utilized were in actuality executing two-dimensional, low-pass spatial filtering. Only in recent years, however, have researchers, such as Nakagawa and Rosenfeld (1978), Goetcherian (1980), and Preston (1982), performed the analysis required to fully explain the characteristics of such filters. It is the purpose of this chapter to both summarize and expand the analysis with emphasis on the effects of the array tessellation, the neighborhood configuration, and other important computational parameters.
KeywordsProbability Density Function Boundary Displacement Filter Operation Major Direction Logical Image
Unable to display preview. Download preview PDF.