Distance transform

About: Distance transform is a research topic. Over the lifetime, 2886 publications have been published within this topic receiving 59481 citations.

Robust Skeletonization through Exact Euclidean Distance Transform and its Application to Neuromorphometry

Abstract: This paper presents how robust 1-pixel-wide and 8-connected skeletons can be obtained simultaneously with exact distance transform calculation. The proposed approach is based on the new concept of exact dilation. Two alternative algorithms for exact Euclidean distance transform calculation allowing exact dilation are described: a simpler approach based on the SEDR (sorted exact distance representation) data structure, which allows exact distance transform calculation; and a more effective strategy based on border propagation. In both techniques the distances are assigned strictly according to sequences of increasing exact distances in the orthogonal lattice. Because of the high accuracy allowed by such procedures, progressive dilations, high quality and accurate 1-pixel-wide and 8-connected skeletons can be obtained corresponding to the frontiers between previously labelled distinct connected objects. Although this method can be useful for determining generalized Dirichlet tessellations, which is also illustrated in this article, its full potential is harnessed by previously segmenting the contours of connected objects by removing their points corresponding to curvature peaks, which are obtained by using an effective multi-scale curvature estimation technique. In such a way, not only high-quality 1-pixel-wide and 8-connected skeletons are obtained for any shape, but also the whole approach becomes considerably robust to small distortions in the object contours, thus avoiding one of the great shortcomings in traditional skeletonization methods. The application of such methods to an important problem in computational neuroscience and neuromorphometry, namely the automated extraction of tapered dendrograms, is described and illustrated. Considerations regarding distances in orthogonal lattices, typical problems in skeletonization, and the practical implementation of the proposed techniques are also included.

Contour-Based Surface Reconstruction using Implicit Curve Fitting, and Distance Field Filtering and Interpolation

Abstract: This paper presents a volumetric approach to reconstructing a smooth surface from a sparse set of parallel binary contours, e.g. those produced via histologic imaging. It creates a volume dataset by interpolating 2D filtered distance fields. The zero isosurface embedded in the computed volume provides the desired result. MPU implicit functions are fit to the input contours, defined as binary images, to produce smooth curves with controllable error bounds. Full 2D Euclidean distance fields are then calculated from the implicit curves. A distance-dependent Gaussian filter is applied to the distance fields to smooth their medial axis discontinuities. Monotonicity-constraining cubic splines are used to construct smooth, blending slices between the input slices. A mesh that approximates the zero isosurface is then extracted from the resulting volume. The effectiveness of the approach is demonstrated on a number of complex, multi-component contour datasets.

Method and apparatus for rendering cell-based distance fields using texture mapping

Abstract: A method and apparatus render a region of a distance field representing an object. The distance field is partitioned into a set of cells, where each cell includes a set of distance samples and a method for reconstructing the distance field within the cell using the distance samples. A set of source cells is selected from the set of cells of the distance field to enable the rendering of the region. Each source cell is represented as a geometric element in a world coordinate system. Each geometric element is associated with a texture map, where the texture map includes distance samples of the corresponding source cell of the geometric element. Each geometric element is transformed from the world coordinate system to a pixel coordinate system and texture mapped, using the distance samples, to determine a distance for each component of each pixel associated with the geometric element. The distance of each component of each pixel is mapped to an antialiased intensity of the component of the pixel.

Image processor for area around vehicle and recording medium

Abstract: PROBLEM TO BE SOLVED: To provide an image processor used for the area around a vehicle and capable of displaying a conspicuous image by converting a birds-eye view image to an image similar to that photographed with a camera or the like and a recording medium. SOLUTION: Step 140 moves a first birds-eye view image stored in an image memory B based on the degree of the movement of a vehicle to obtain the birds-eye view image obtained after moving the vehicle. Step 160 composites the birds-eye view image obtained after moving the vehicle and a second birds- eye view image to prepare a composite birds-eye view image. Step 180 applies reverse birds-eye view conversion to the composite birds-eye view image to prepare a projected image. Step 190 stores the projected image in an image memory C. Step 200 adds an image displaying the vehicle to display the projected image stored in the image memory C on a monitor 3. COPYRIGHT: (C)2003,JPO