 |
Color Look-up Tables
Substituting a palette of colors for the brightness values of a monochrome image produces a false-color or pseudo-color result that in some cases makes it easier to see small changes in brightness, or to compare the brightness of features. Because most people can see color, and can distinguish hundreds of colors, vs. only tens of gray scale brightness levels, this seems like an appealing idea and is very widely used.
If the color look-up table (CLUT) has colors that change gradually, for instance through a rainbow or heat scale, the overall impression of the image is retained but small changes are not easily detected. If, on the other hand, the colors oscillate wildly or randomly, small changes become visible but the gestalt of the image is lost. Finding a color table that suits the needs of a particular image and situation is difficult at best. This interactive tutorial illustrates the substitution of colors from a table for the grayscale brightness values of the original pixels.
The tutorial initializes with a randomly selected specimen appearing in the Specimen Image window. The Choose A Specimen pull-down menu provides a selection of specimen images, in addition to the initial randomly chosen one. The Choose A LUT pull-down menu provides a selection of several Look-up Tables (which are displayed) which produce the resulting Output Image shown on the right.
Contributing Authors
John C. Russ - Materials Science and Engineering Dept., North Carolina State University, Raleigh, North Carolina, 27695.
Matthew Parry-Hill, and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.
BACK TO INTRODUCTION TO DIGITAL IMAGE PROCESSING AND ANALYSIS
BACK TO MICROSCOPY PRIMER HOME
Questions or comments? Send us an email.
© 1998-2009 by Michael W. Davidson, John Russ, Olympus America Inc., and The Florida State University. All Rights Reserved. No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Tuesday, Sep 11, 2018 at 01:58 PM
Access Count Since July 20, 2006: 10361
For more information on microscope manufacturers,
use the buttons below to navigate to their websites:
