David Doria, “A Conditional Mesh Front Iterator for VTK“. The VTK Journal, April 2010

Region growing is a technique that can be used to propagate information over a mesh. In a previous submission, “A Mesh Front Iterator for VTK”, we introduced an iterator that can be used with vtkPointSet subclasses to traverse …

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We present a system for filling holes in an image by copying patches from elsewhere in the image. These patches should be a good continuation of the hole boundary into the hole. There is typically no “right answer” as we are extrapolating image data into …

David Doria, “Reading a PTX file into an itkMesh“. The Insight Journal, September 2009

This document presents a set of classes to read a PTX file (a common file format produced by LiDAR scanners) into an itkMesh object. We propose these classes as addition to the Insight Toolkit.

This document presents an implementation of an algorithm to find a low edge-count approximation of a complex, discrete, 2D closed contour. This implementation is based on the algorithm described in “Using Aerial Lidar Data to Segment And Model Buildings” and “A Bayesian Approach to Building Footprint Extraction from Aerial LIDAR Data.”

The code is available …

This document presents an implementation of an algorithm to perform a morphological opening on a graph. The intent is to remove short branches in a graph while preserving the large scale structure. This implementation is based on the algorithm described in “Efficient Closed Contour Extraction from Range Image’s Edge Points”. We have used the data …

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Two very related problems in image processing are hole filling and compositing. This article explains an implementation of similar algorithms to solve both of these problems – poisson editing and poisson cloning; both …

David Doria, “Region Growing Using a Criterion on the Region Boundary“. The Insight Journal, August 2009

This document presents a set of classes which implement a region growing algorithm whose criterion for growth is different than existing ITK region growing algorithms. The region is grown into the query pixel based only on …

David Doria, “A Leica PTX Reader for VTK“. The VTK Journal, March 2010

Leica LiDAR scanners output points in the PTX file format. It is often useful to convert this format to a standard VTK point cloud or mesh format before processing. We propose a new class, vtkPTXReader, to provide this functionality.

David Doria, “A VTK Interface for the Hokuyo UTM 30LX Laser Range Finder“. The VTK Journal, October 2010

It is convenient to acquire data in a format which VTK can read directly. To enable this, we provide a wrapper of the Hokuyo UTM-30LX interface in a class vtkHokuyo.

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This document presents a GUI application to manually select corresponding points in two data sets. The data sets can each be either an image or a point cloud. If both data sets are images, the functionality is equivalent to Matlab’s ‘cpselect’ function. There are many uses of …

David Doria, “Expectation Maximization of Gausian Mixture Models in VTK“. The VTK Journal, September 2010

Expectation maximization (EM) is a common technique for estimating the parameters of a model after having collected observations of data generated by the model. We first explain the algorithm, then present our impelementation. We focus on estimation …

David Doria, “Point Set Surface Reconstruction for VTK“. The VTK Journal, March 2010

This document presents a set of classes (vtkPointSetSurfaceReconstruction, vtkVoxelizePolyData) to produce a surface from an oriented point set. These classes are implemented as VTK filters. A Paraview plugin interface is provided to allow extremely easy experimentation with the new …

David Doria, “A Mesh Front Iterator for VTK“. The VTK Journal, April 2010

Region growing is a technique that can be used to propagate information over a mesh. We provide an iterator that can be used with vtkPointSet subclasses to traverse a mesh in a reasonable fashion. A “front” is emanated from …

David Doria “Poisson Editing in ITK“. The Insight Journal, March 2011

This code provides an implementation of two techniques from “Poisson Image Editing” on ITK images. First, we fill a hole in an image given only the pixel values on the boundary. Second, we copy a patch of an image into …

David Doria, “Graph Cuts Based Super Pixel Segmentation for VTK“. The VTK Journal, March 2010

Segmenting images into “super pixels” is lately a very hot topic. One implementation of such a technique is by Felzenszwalb and Huttenlocher. We propose a new class, vtkSuperPixelSegmentation, which has wrapped Felzenszwalb’s code (with permission) to provide …

This document presents an implementation of two algorithms, Voronoi Neighbors and Binary Space Partition (BSP) Neighbors. These algorithms find neighbors of a point in a point set that are somehow “better” than a “K nearest neighbors” or a “all neighbors within a radius” query. This type of nearest neighbor query is more computationally expensive, but …

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This document presents a VTK implementation of the algorithm described in “A clustering method for efficient segmentation of 3D laser data” by Klasing, Klaas Wollherr, Dirk, and Buss, Martin.

The code is available here.

David Doria, “A Mean Shift Clustering Implementation for VTK“. The VTK Journal, September 2010

Mean shift clustering is an excellent technique for clustering points when the number of clusters is not known. We present a implementation (vtkMeanShiftClustering) of the simplest version of the algorithm written in a VTK context.

David Doria “Loopy Belief Propagation on MRFs in ITK “. The Insight Journal, March 2011

This code provides a base implementation of Loopy Belief Propagation on MRFs in ITK. We use binary image denoising as an example problem to demonstrate this code. This document is intended only to describe the implementation, not …

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This code provides an implementation of a simple technique to fill small holes in an image. We use a multi-pass method that fills pixels on the border of a hole with the average of its non-hole 8-connected neighbors. This process is repeated until all holes are filled.

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