Sohail A. Dianat

Control of Color Imaging Systems: Analysis and Design

Preface Acknowledgments An Overview of Digital Printing Systems Introduction Printing and Publishing System Digital Front End Digital Print Engine (Electrophotographic) Evolution of Controls Technology for Digital Printers-Color Controls View Prepress-Based Processing DFE-Based Processing Print Engine-Based Processing References Fundamentals of Digital Image Processing Introduction Digital Image Formation and Systems Optical and Modulation Transfer Functions Image Sampling and Quantization Image Transform Image Filtering Image Resizing Image Enhancement Image Restoration Image Halftoning Problems References Mathematical Foundations Introduction General Continuous-Time System Description Laplace Transform General Linear Discrete-Time Systems z-Transform Discrete-Time Fourier Transform Two-Dimensional z-Transform Two-Dimensional Discrete-Space Fourier Transform Eigenvalues and Eigenvectors Singular Value Decomposition Matrix Polynomials and Functions of Square Matrices Fundamentals of Matrix Calculus Problems References State-Variable Representation Introduction Concept of States State-Space Representation of Continuous-Time Systems State-Space Representation of General Continuous LTI Systems Solution of LTI Continuous-Time State Equations State-Space Representation of Discrete-Time Systems State-Space Representation of Discrete-Time LTI Systems Solution of LTI Discrete-Time State Equations Controllability of LTI Systems Observability of LTI Systems Problems References Closed-Loop System Analysis and Design Introduction State Feedback LQR Design State Estimators (Observers) Design Combined State Estimation and Control Problems References Interpolation of Multidimensional Functions Introduction Interpolation of Uniformly Spaced Lookup Tables Nonuniformly Spaced Lookup Tables Lookup Table Inverse Compression of Lookup Tables Smoothing Algorithm for Multidimensional Functions Problems References Three-Dimensional Control of Color Management Systems Introduction Image Path Architecture Profiling-A Complex System Problem Characterization of Color Systems GCR Selection and Inversion Gamut-Mapping Methods Evaluation of Profiles An Example Showing How to Build Multidimensional LUT Problems References One-Dimensional, Two-Dimensional, and Spot-Color Management and Control Methods Introduction Principles of Color Management One-Dimensional Gray-Balance Calibration Two-Dimensional Calibration One-Dimensional and Two-Dimensional Printer Calibration Using Printer Models One-Dimensional and Two-Dimensional Printer Calibration with State-Feedback Methods Spot-Color Control Problems References Internal Process Controls Introduction Process Control Models-A General Control View Time Hierarchical Process Control Loops Level 1 Electrostatic Control System State Space to Transfer Function Conversions Level 2 Developability Controller Steady-State Error Design of the Gain Matrix Level 3 Control Loops Dead Beat Response TC Control Loop Process Controls Under Limited Actuation Optimal Controls for Selective States Optimal Measurements Problems References Printing System Models Introduction Process Models Modulation Transfer Functions Tone Reproduction Curve Image Simulation with Fusing and Color Models Virtual Printer Color Gamut Virtual Printer Model Tuning to an Experimental Printer Problems References Appendices (A-C) Index

Optimized vector bilateral filter for multispectral image denoising

Vector bilateral filtering has been shown to provide several advantages in processing hyperspectral images such as good noise removal while minimizing edge degradation, and dynamic range enhancement of bands with impaired signal to noise ratios. This paper introduces an approach for selection of the parameters of a vector bilateral filter through an optimization procedure rather than by ad hoc means. The approach is based on posing the filtering problem as one of nonlinear estimation and minimizing the Steins unbiased risk estimate (SURE) of this nonlinear estimator. Experimental results show that the optimized vector bilateral filter provides improved denoising performance on multispectral images when compared to several other approaches.

Toward a control oriented model of xerographic marking engines

This paper presents some preliminary results from a research collaboration concerning the modeling and control of color xerography. In this first communication of our work, we describe our efforts to develop a model for a monochrome marking engine. We adopt the technique of principal component analysis for choice of output coordinates and demonstrate preliminary experimental evidence suggesting that this procedure yields accuracy in data reconstruction superior to present industry practice. Preliminary analysis of the experimental evidence suggests that the process has a nonlinear component that we seek to model using a mixture of physical and empirical insight.

Nonnegative matrix factorization with deterministic annealing for unsupervised unmixing of hyperspectral imagery

Non-negative matrix factorization (NMF) technique and its extensions were developed to find part based, linear representations of non-negative multivariate data. They have been shown to provide more interpretable results with realistic non-negative constrain in unsupervised learning applications such as hyperspectral imagery unmixing, image feature extraction, and data mining. This paper extends the NMF method by incorporating deterministic annealing optimization procedure, which will help solve the non-convexity problem in NMF and provide a better choice of sparseness constrain. The approach is based on replacing the difficult non-convex optimization problem of NMF with an easier one by adding an auxiliary convex entropy constrain term and solving this first. Experiment results with hyperspectral unmixing application show that the proposed technique provides improved unmixing performance compared to other state-of-the-art methods.

Semi-automatic 3-D segmentation of Computed Tomographic imagery by iterative gradient-driven volume growing

We propose a novel gradient driven methodology for three dimensional (3-D) segmentation of Computed Tomographic (CT) imagery. Our approach begins interactively where-in a user marks a set of voxels within the cross-section of a Sub-Volume Of Interest (SVOI), using a single slice of the CT volume. Subsequently, a 3-D gradient detection scheme is utilized to determine the radiodensity variations across the volume. The resultant gradient information is employed in an iterative volume growing procedure, which is initiated at voxels with small gradient magnitudes adjoining the user-selected voxels and culminates at voxels with large gradient magnitudes, to arrive at the final 3-D segmentation result of the SVOI. The aforementioned method was tested on multiple studies and the results show favorable performance against a state-of-the-art technique.

Code Division Multiple Access

An alternative to frequency division and time division multiple access schemes is provided by code division multiple access (CDMA), which permits multiple users to transmit simultaneously over a channel while occupying the same frequency band. This is effected by assigning a unique code or signature to each user. As we will see, CDMA offers several advantages. Various schemes have been devised to generate the codes; this chapter will introduce the fundamentals of direct-sequence spread spectrum CDMA (DS-CDMA).