Using unbalanced operators to reduce loss of information during image enhancement
L.G. Allred, Gary E. Kelly · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1992
Image processing operations involve replacing the color hue at a given pixel by computations involving the color values of surrounding pixels. Traditional image enhancement computations employ a 3 by 3 matrix manipulation involving a pixel and its eight neighboring pixels. Although some information loss results from any image processing technique, the use of a 3 by 3 operator typically results in a 50% loss of detail. This paper investigates unbalanced operators which do not seem to possess this deficiency. In particular, 2 by 2 operators can eliminate as much noise as 3 by 3 operators with less loss of detail. The enhanced image can be interpreted as a `balanced' operation with a 1/2 pixel shift of the original image for each operation performed. In four successive operations, a border 2 pixel band is lost on 2 edges of the image. In our applications, the loss of a few borer raster lines is insignificant when compared to a 50% loss of detail.