Development of an automated 12-8 bit conversion algorithm for displaying and archiving scanned radiographs

The lossless capture of the entire range of optical densities encountered i n a radiograph can require up to 4000 individual shades of gray. Most inexp ensive computer displays, and most grayscale image formats contain only 256 gray shades. To use these systems, a look up table must be generated to di splay the scanned image, which maps the approximately 4000 gray shades in t he digitized radiograph to the 256 gray shades on the monitor. However, if this conversion is inappropriately performed, much of the information conta ined in the original image could be lost, This study was undertaken to deve lop an histogram equalization algorithm that would automatically convert th e 4000 gray shade digitized radiograph into a 256 gray shade image file, wi thout perceptable loss of diagnostic information or image quality.