Skip to main content
Top

2011 | Book

Statistical Image Processing and Multidimensional Modeling

insite
SEARCH

About this book

Images are all around us! The proliferation of low-cost, high-quality imaging devices has led to an explosion in acquired images. When these images are acquired from a microscope, telescope, satellite, or medical imaging device, there is a statistical image processing task: the inference of something—an artery, a road, a DNA marker, an oil spill—from imagery, possibly noisy, blurry, or incomplete. A great many textbooks have been written on image processing. However this book does not so much focus on images, per se, but rather on spatial data sets, with one or more measurements taken over a two or higher dimensional space, and to which standard image-processing algorithms may not apply. There are many important data analysis methods developed in this text for such statistical image problems. Examples abound throughout remote sensing (satellite data mapping, data assimilation, climate-change studies, land use), medical imaging (organ segmentation, anomaly detection), computer vision (image classification, segmentation), and other 2D/3D problems (biological imaging, porous media). The goal, then, of this text is to address methods for solving multidimensional statistical problems. The text strikes a balance between mathematics and theory on the one hand, versus applications and algorithms on the other, by deliberately developing the basic theory (Part I), the mathematical modeling (Part II), and the algorithmic and numerical methods (Part III) of solving a given problem. The particular emphases of the book include inverse problems, multidimensional modeling, random fields, and hierarchical methods.

Table of Contents

Frontmatter
1. Introduction
Abstract
Images are all around us! Inexpensive digital cameras, video cameras, computerwebcams, satellite imagery, and images off the Internet give us access to spatial imagery of all sorts. The vast majority of these images will be of scenes at human scales – pictures of animals / houses / people / faces and so on – relatively complex images which are not well described statistically or mathematically. Many algorithms have been developed to process / denoise / compress / segment such images, described in innumerable textbooks on image processing [36, 54, 143, 174, 210], and briefly reviewed in Appendix C.
Paul Fieguth

Inverse Problems and Estimation

Frontmatter
2. Inverse Problems
Abstract
An understanding of forward and inverse problems [12, 301] lies at the heart of any large estimation problem. Abstractly, most physical systems can be defined or parametrized in terms of a set of attributes, or unknowns, from which other attributes, or measurements, can be inferred. In other words, the quantities \(\underline{m}\) which we measure are some mathematical function
$$\underline{m} = f(\underline{Z})$$
(2.1)
of other, more basic, underlying quantities \(\underline{z},\) where f may be deterministic or stochastic. In the special case when f is linear, a case of considerable interest to us, then (2.1) may be expressed as
$$\underline{m} = C\underline{Z} \quad {\rm or} \quad \underline{m} = C\underline{Z} + \underline{v}$$
(2.2)
for the deterministic or stochastic cases, respectively. Normally \(\underline{z},\) is an ideal, complete representation of the system: detailed, noise-free, and regularly structured (e.g.,pixellated), whereas the measurements \(\underline{m},\) are incomplete and approximate: possibly noise-corrupted, irregularly structured, limited in number, or somehow limited by the physics of the measuring device.
Paul Fieguth
3. Static Estimation and Sampling
Abstract
This chapter derives the two fundamental linear estimators: Section 3.1: The non-Bayesian linear least-squares estimator Section 3.2: The Bayesian linear least-squares estimator Throughout this chapter we concern ourselves with the derivation of algebraic estimators \(\underline{\hat{z}}\) for some random vector \(\underline{z}\), but ignoring the issues of what \(\underline{z}\) represents, or any concerns regarding its size, both of which are extremely important and are examined closely beginning with Chapter 5.
Paul Fieguth
4. Dynamic Estimation and Sampling
Abstract
Chapter 3 developed estimators for static problems — those in which \(\underline{z}\) has no time dependence.Given measurements, we compute a corresponding set of estimates, and the solution is complete.
Paul Fieguth

Modelling of Random Fields

Frontmatter
5. Multidimensional Modelling
Abstract
In principle, the extension to multidimensional \(\underline{z}\) of the concepts of regularization from Chapter 2 and the static and dynamic estimators of Chapters 3 and 4 is perfectly straightforward. The only inherent limitation in the developed estimators is that the unknowns \(\underline{x}\) and measurements \(\underline{m}\) are required to be column vectors. Attempting to substitute matrices (e.g., a measured image) for \(\underline{m}\) will yield meaningless results.
Paul Fieguth
6. Markov Random Fields
Abstract
Based on the modelling discussions of Chapter 5, the issues of computational and storage complexity for large problems have motivated an interest in sparse representations, and also in those models which allow some sort of decoupling, or domain decomposition, to allow a hierarchical approach. As we shall see, both sparsity and domain decomposition are at the heart of all Markov processes, thus the topic of Markovianity is central to the modelling and processing on large domains.
Paul Fieguth
7. Hidden Markov Models
Abstract
Working with nonstationary and heterogeneous random fields presents an interesting challenge. In principle, the modelling methods of Chapter 5 do allow us to construct a nonstationary model, under the assumption that the model boundaries are known.
Paul Fieguth
8. Changes of Basis
Abstract
The previous chapters have focused on the definition of a model, and corresponding estimator or sampler, for some random vector \(\underline{Z}\). Explicit throughout the preceding chapters has been the assumption that \(\underline{Z}\) contains a set of spatial elements or image pixels; that is, that \(\underline{Z}\) represents the raw, underlying random field of interest.
Paul Fieguth

Methods and Algorithms

Frontmatter
9. Linear Systems Estimation
Abstract
One of the most fundamental equations in this book is the solution to the Bayesian linear least-squares estimator of (3.114):
$$\underline{\hat{z}}(\underline{m})= {\underline{\mu}} = \left(P^{-1}+ C^{T}R^{-1}C\right)^{-1} C^{T} R^{-1}(\underline{\mu}- C_{\underline{m}})$$
(9.1)
$$\tilde{P} = cov(\underline{\tilde{z}}) = (P^{-1} = C^{T} R^{-1} C)^{-1}$$
(9.2)
Paul Fieguth
10. Kalman Filtering and Domain Decomposition
Abstract
In this chapter we examine the solution of large dynamic estimation problems, problems which may stem from one of two sources: 1. Problems which are inherently spatio-temporal, such as the processing of video (spatial two-dimensional images over time) or remote sensing (the earth’s surface or an atmospheric/oceanic volume sampled over time); 2. Multidimensional static problems, which have been converted to dynamic form, as discussed below.
Paul Fieguth
11. Sampling and Monte Carlo Methods
Abstract
The matter of statistical sampling was discussed in Chapter 2: Prior Samplingin Section 2.5.2, and Posterior Sampling in Section 2.5.4. Given a random variable \(\underline{z}\) obeying some prior probability density function \(p(\underline{z})\), sampling from the prior distribution means generating independent random samples \(\ \underline{z}_1,\underline{z}_2,\ldots {\rm from}\ p(\underline{z}): \)
$${\underline{z}_i}\sim p(\underline{z}),$$
(11.1)
and similarly posterior sampling from a distribution conditioned on measurements:
$$({\underline{z}_i}|\underline{m})\sim p(\underline{z}|\underline{m}).$$
(11.2)
Paul Fieguth

Appendices

Frontmatter
A. Algebra
Paul Fieguth
B. Statistics
Abstract
This appendix provides a brief summary of univariate and multivariate statistics, covariances, and simple transformations of random variables. For a more detailed review the reader is referred to [37, 76, 99, 248,284].
Paul Fieguth
C. Image Processing
Abstract
Although this text is not about image processing per se, some familiarity with common concepts in image processing, such as convolution or denoising, is very helpful. This appendix is only a brief list of concepts, and is in no way a comprehensive tutorial on image processing, for which the interested reader is referred to any one of many excellent textbooks [36, 54, 143, 174, 210].
Paul Fieguth
Backmatter
Metadata
Title
Statistical Image Processing and Multidimensional Modeling
Author
Paul Fieguth
Copyright Year
2011
Publisher
Springer New York
Electronic ISBN
978-1-4419-7294-1
Print ISBN
978-1-4419-7293-4
DOI
https://doi.org/10.1007/978-1-4419-7294-1

Premium Partner