User`s guide

Chapter 1:Introduction to Image Processing

4 - ScanShop User’s Guide

Gamma Tables

Gamma tables are useful for improving the appearance of scanned images or for

removing undesirable components of scanned originals. This effect is attained by

substituting values for pixels different from those read by the scanner’s image

sensor.

Monitors and output devices, being different kinds of devices, have different

physics associated with their display of images — monitors transmit light; paper

printouts absorb and reﬂect light. As a result, a scanned image displayed on a

monitor or printed on paper will look different from its original. The difference

between the original and a reproduction can be characterized by a gamma

function.

Gamma features are provided in most scanners and provide results with no

scanning-time penalty. ScanShop provides gamma table selections you can

control to get the processing that you desire.