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Type of Document Master's Thesis
Author Cois, C. Aaron
URN etd-05162006-155257
Title Shells and Spheres: A Novel Framework for Variable Scale Statistical Image Analysis
Degree Master of Science
Program Computer Science
School School of Arts and Sciences
Advisory Committee
Advisor Name Title
Dr. George Stetten Committee Co-Chair
Dr. Milos Hauskrecht Committee Co-Chair
Dr. C. C. Li Committee Member
Keywords
  • medical imaging
  • medical image analysis
  • image processing
  • computer vision
  • image segmentation
Date of Defense 2006-05-09
Availability unrestricted
Abstract
A framework for analyzing images, called emph{Shells and Spheres},

has been developed based on a set of spheres with adjustable radii,

with exactly one sphere centered at each image pixel. This set of

spheres, known as a emph{sphere map}, is considered optimized when

each sphere reaches, but does not cross, the nearest boundary.

Calculations denoted as emph{Variable-Scale Statistics} (VSS) are

performed on populations of pixels within spheres, as well as

populations of adjacent and overlapping spheres, in order to deduce

the proper radius of each sphere. Spheres grow or shrink by adding

or deleting an outer shell one pixel thick . Unlike conventional

fixed-scale kernels, our spherical operators consider as many pixels

as possible to differentiate between objects and accurately

delineate boundaries. The term ``sphere" is used for brevity, though

the approach is not limited to 3D and is valid in $n$-dimensions.

The approach is illustrated using both real images and noiseless

synthetic images containing objects with uniform intensity, and more

closely examined and validated using various synthetic images with

added white noise and multiple contrast enhanced CT scans of the

aortic arch. A particular algorithm using Shells and Spheres is

described and demonstrated on segmentation of the aortic arch in a

contrast-enhanced CT scan, both in 2D and 3D.

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