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This document presents a set of classes to enable operations on itkPointSet objects. In particular, itkTransformPointSetFilter allows a transformation to be applied to a set of points. We propose these classes as addition to the Insight Toolkit ITK.

The current ITK release (2.8) already contains a filter that enables permuting coordinate axes of an image: PermuteAxesImageFilter. PermuteAxesTransform provides similar functionality in form if ITK transform. It enables permuting axes as a part of image [...]

Polar transform is a geometric transform, that transforms points form cartesian coordinates to so-called polar coordinates. In case of 2D space, a point in polar coordinate system is addressed by radius and angle. In image processing, polar transform is [...]

The computation speed for distance transforms becomes important in a wide variety of image processing applications. Current ITK library filters do not see any benefit from a multithreading environment. We introduce a three-dimensional signed parallel [...]

Fast computation of distance transforms find direct application
in various computer vision problems. Currently there exists
two image filters in the ITK library which can be used to generate
distance maps. Unfortunately, these
filters produce only [...]

We have implemented an Order K Distance Transform filter. The Order K distance transform computes the distances to the k nearest foreground pixels. Additionally the Order K Voronoi diagram can be computed.
This work was supported in part by R21 MH67054, NSF [...]

It is often useful to be able to compute the component of image gradient in a direction defined by a shape of some form, rather than relative to the image axis. This article introduces a simple method for doing this based on distance transforms that is [...]

A Generalized Squared Euclidean Distance Transform with Voronoi Maps

Published in The Insight Journal

Published in The Insight Journal

This document describes the implementation of an algorithm that computes a generalization of the distance transform with the squared euclidean metric.
The generalization allows for interesting image operators, e.g. a morphologic dilation with euclidean ball [...]

This report discusses various definitions and implementations of the watershed transform as well as providing an introduction to some well known techniques for applying the watershed transform to practical problems. The discussion will be focused on new and [...]

Although phase data can take on any value, it is generally only possible to measure phase as a principle value, i.e., wrapped within the range (-pi,pi]. Determining the unwrapped phase from its principle value is a topic of considerable interest in magnetic [...]

This document describes a module that extends the Insight Toolkit, ITK, which reads DICOM Spatial Rogistration Object files in itk::Transform's. Currently, DICOM files are read by applying the DCMTK library as a backend. An itk::DCMTKTransformIO class can be [...]

N-Dimensional Computation of Strain Tensor Images in the Insight Toolkit

Published in The Insight Journal

Published in The Insight Journal

Strain quantifies local deformation of a solid body. In medical imaging, strain reflects how tissue deforms
under load. Or, it can quantify growth or atrophy of tissue, such as the growth of a tumor. Additionally,
strain from the transformation that results [...]

Phase Correlation Method (PCM or SPOMF - Symmetric Phase-Only Matched Filter) is a well known image registration method, that exploits Fourier Shift Theorem property of Fourier Transform. Even though it is limited to estimate only shifts between two images, [...]

This work describes the implementation of computational geometry algorithms developed within the Insight Toolkit (ITK): Distance Transform (DT), Voronoi diagrams, k Nearest Neighbor (kNN) transform, and finally a K Nearest Neighbor classifier for multichannel [...]

The graph windowed Fourier transform: a tool to quantify the gyrification of the cerebral cortex

Published in The MIDAS Journal

Published in The MIDAS Journal

The Gyrification Index (GI) quantifies the amount of folding of a cortical surface. In this paper, we show the efficiency of spectral analysis to perform such a task, and in particular we explain how the graph windowed Fourier transform can be used as a tool [...]

An Intelligent cluster-based segmentation using Wavelet Features:Application to Medical Images

Published in The MIDAS Journal

Published in The MIDAS Journal

Segmentation forms the onset for image analysis especially for medical images, making any abnormalities in tissues distinctly visible. Possible application includes the detection of tumor boundary in SPECT, MRI or electron MRI (EMRI). Nevertheless, tumors [...]

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