Summary: IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 15, NO. 8, AUGUST 2006 2303
Gray-Level Grouping (GLG): An Automatic
Method for Optimized Image Contrast
Enhancement--Part II: The Variations
ZhiYu Chen, Senior Member, IEEE, Besma R. Abidi, Senior Member, IEEE, David L. Page, Member, IEEE, and
Mongi A. Abidi, Member, IEEE
Abstract--This is Part II of the paper, "Gray-Level Grouping
(GLG): an Automatic Method for Optimized Image Contrast
Enhancement". Part I of this paper introduced a new automatic
contrast enhancement technique: gray-level grouping (GLG).
GLG is a general and powerful technique, which can be conve-
niently applied to a broad variety of low-contrast images and
outperforms conventional contrast enhancement techniques.
However, the basic GLG method still has limitations and cannot
enhance certain classes of low-contrast images well, e.g., images
with a noisy background. The basic GLG also cannot fulfill certain
special application purposes, e.g., enhancing only part of an image
which corresponds to a certain segment of the image histogram.
In order to break through these limitations, this paper introduces
an extension of the basic GLG algorithm, selective gray-level