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Distance transform

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


Papers
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Journal ArticleDOI
TL;DR: A new approach to shape representation called a composite adaptively sampled distance field (composite ADF) is described and its application to NC milling simulation and an implementation of 3 and 5-axis milling Simulation is described.
Abstract: We describe a new approach to shape representation called a composite adaptively sampled distance field (composite ADF) and describe its application to NC milling simulation. In a composite ADF each shape is represented by an analytic or procedural signed Euclidean distance field and the milled workpiece is given as the Boolean difference between distance fields representing the original workpiece volume and distance fields representing the volumes of the milling tool swept along the prescribed milling path. The computation of distance field of the swept volume of a milling tool is handled by an inverted trajectory approach where the problem is solved in tool coordinate frame instead of a world coordinate frame. An octree bounding volume hierarchy is used to sample the distance functions and provides spatial localization of geometric operations thereby dramatically increasing the speed of the system. The new method enables very fast simulation, especially of free-form surfaces, with accuracy better than 1 micron, and low memory requirements. We describe an implementation of 3 and 5-axis milling simulation.

56 citations

Patent
31 May 2000
TL;DR: In this article, a method and system for determining pupillary distance and multi-focal element height for prescription eyeglasses via images received through a computer network is presented, where a reference object of a known real-world size located approximately the same distance from the camera as the face is determined, such as by measuring the number of pixels across the reference object.
Abstract: A method and system is presented for determining pupillary distance and multi-focal element height for prescription eyeglasses via images received through a computer network. The received image has a reference object of a known real-world size located approximately the same distance from the camera as the face. The size of the reference object on the image is determined, such as by measuring the number of pixels across the reference object. A scale for the image is determined by dividing the real world width of the reference object by the image size of the reference object. An image value for the pupillary distance and multi-focal element height is then determined. The scale value is applied to the image value to determine the real-world pupillary distance and multi-focal element height for the patient. The reference object can be a generally available object such as a monetary coin, or a facial element that has a relatively fixed size from face to face, such as the size of the iris. Image sizes can be determined by presenting the image to an individual, or through image recognition technology.

56 citations

Journal ArticleDOI
TL;DR: An algorithm to generate a cell‐and‐portal decomposition of general indoor scenes, an adaptation of the 3D watershed transform, computed on a distance‐to‐geometry sampled field and able to deal with classical architectural models, as well as cave‐like environments and large mixed indoor/outdoor scenes.
Abstract: We present an algorithm to generate a cell-and-portal decomposition of general indoor scenes. The method is an adaptation of the 3D watershed transform, computed on a distance-to-geometry sampled field. The watershed is processed using a flooding analogy in the distance field space. Flooding originates from local minima, each minimum producing a region. Portals are built as needed to avoid the merging of regions during their growth. As a result, the cell-and-portal decomposition is closely linked to the structure of the models. In a building, the algorithm finds all the rooms, doors and windows. To restrict the memory load, a hierarchical implementation of the algorithm is presented. We also explain how to handle possible model degeneracies -such as cracks, holes and interpenetrating geometries- using a pre-voxelisation step. The hierarchical algorithm, preceded when necessary by the pre-voxelisation, was tested on a large range of models. We show that it is able to deal with classical architectural models, as well as cave-like environments and large mixed indoor/outdoor scenes. Thanks to the intermediate distance field representation, the algorithm can be used regardless of the way the model is represented: it deals with parametric curves, implicit surfaces, volumetric data and polygon soups in a unified way.

56 citations

Proceedings ArticleDOI
05 Oct 1999
TL;DR: The main idea is to employ discrete distance fields enhanced with correspondence information that allows us not only to connect vertices from successive slices in a reasonable way but also to solve the branching problem by creating intermediate contours where adjacent contours differ too much.
Abstract: In this paper we consider the problem of reconstructing triangular surfaces from given contours. An algorithm solving this problem has to decide which contours of two successive slices should be connected by the surface (branching problem), and, given that, which vertices of the assigned contours should be connected for the triangular mesh (correspondence problem). We present a new approach that solves both tasks in an elegant way. The main idea is to employ discrete distance fields enhanced with correspondence information. This allows us not only to connect vertices from successive slices in a reasonable way but also to solve the branching problem by creating intermediate contours where adjacent contours differ too much. Last but not least we show how the 2D-distance fields used in the reconstruction step can be converted to a 3D-distance field that can be advantageously exploited for distance calculations during a subsequent simplification step.

55 citations

Journal ArticleDOI
TL;DR: This paper proposes a kernel approach to improve the retrieval performance of CBIR systems by learning a distance metric based on pairwise constraints between images as supervisory information and defines the transformation in the kernel-induced feature space which is nonlinearly related to the image space.

55 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20235
202217
202161
202099
2019112
201881