Files in this item

FilesDescriptionFormat

application/pdf

application/pdfnam_myra.pdf (13MB)
(no description provided)PDF

Description

Title:Data-driven Automatic Edge Sharpening
Author(s):Nam, Myra
Advisor(s):Ahuja, Narendra
Contributor(s):Ahuja, Narendra
Department / Program:Electrical & Computer Eng
Discipline:Electrical & Computer Engr
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):edge-sharpening
cumulative logistic regression
Image Enhancement
Perception
Abstract:Sharpening is a powerful image transformation because sharp edges can bring out image details. Sharpness is achieved by increasing local contrast and reducing edge widths. We present a method that enhances sharpness of images and thereby their perceptual quality. Most existing enhancement techniques require user input to improve the perception of the scene in a manner most pleasing to the particular user. Our goal of image enhancement is to improve the perception of sharpness in digital images for human viewers. We consider two parameters in order to exaggerate the differences between local intensities. The two parameters exploit local contrast and widths of edges. We start from the assumption that color, texture, or objects of focus such as faces affect the human perception of photographs. When human raters are presented with a collection of images with different sharpness and asked to rank them according to perceived sharpness, the results have shown that there is a statistical consensus among the raters. We introduce a ramp enhancement technique by modifying the optimal overshoot in the ramp for different region contrasts as well as the new ramp width. Optimal parameter values are searched to be applied to regions under the criteria mentioned above. In this way, we aim to enhance digital images automatically to create pleasing image output for common users.
Issue Date:2010-01-06
URI:http://hdl.handle.net/2142/14685
Rights Information:Copyright 2009 Myra Nam
Date Available in IDEALS:2010-01-06
Date Deposited:December 2


This item appears in the following Collection(s)

Item Statistics