We present a novel kernel regression framework for smoothing scalar surface data using the Laplace-Beltrami eigenfunctions. Starting with the heat kernel constructed from the eigenfunctions, we formulate a new bivariate kernel regression framework as a weighted eigenfunction expansion with the heat kernel as the weights. The new kernel method is mathematically equivalent to isotropic heat diffu...

BACKGROUND AND PURPOSE CT is a ubiquitous, efficient, and cost-effective method to evaluate pediatric ventricular size, particularly in patients with CSF shunt diversion who often need emergent imaging. We therefore sought to determine the minimum dose output or CT dose index required to produce clinically acceptable examinations. MATERIALS AND METHODS Using a validated noise insertion method...

Ambiguity in the solution of inverse problems arises when data are insufficient to define a unique solution (i.e., the problem is ill-posed). Data fusion has the potential to reduce this ambiguity by using other sensory data that complement the original data. This paper examines the application of data fusion to limited-angle computed tomography (CT) to resolve ambiguity. While CT in its conven...

OBJECTIVE To develop an algorithm to measure the dimensions of an airway oriented obliquely on a volumetric CT, as well as assess the effect of the imaging parameters on the correct measurement of the airway dimension. MATERIALS AND METHODS An airway phantom with 11 poly-acryl tubes of various lumen diameters and wall thicknesses was scanned using a 16-MDCT (multidetector CT) at various tilt ...

This work addresses the problem of detecting clusters in a weighted, undirected, graph by using kernel-based clustering methods, directly partitioning the graph according to a welldefined similarity measure between the nodes (a kernel on a graph). The proposed algorithms are based on a two-step procedure. First, a kernel or similarity matrix, providing a meaningful similarity measure between an...

The occam programming language, based on the CSP formal algebra and tied to a specific hardware platform (transputers), offered a structured way to organize concurrency. The CT library [1], developed at University of Twente, inspired by occam is a kernel library implementing occam primitives in modern programming languages and for general purpose microprocessors. In this paper, a practical impl...

Introduction: Polymer gel dosimeters contain chemical materials sensitive to the radiation which are polymerized by the radiation as a function of absorbed dose. So information of spatial dose distribution can be extracted by imaging from irradiated gel. Among imaging techniques, computed tomography (CT) poses as an attractive method because of practical advantages such as acce...

In infant CT scans, it is important to minimize radiation exposure without lowering the quality of the diagnosis. Therefore, appropriate parameters for infant CT scan should be considered at each institute. In order to determine parameters for infant body CT, we measured the physical characteristics of our current CT machine and evaluated scan parameters as S.D. below 10 on the basis of literat...