121993192
Recognition by Functional Parts
Abstract We present an approach to function-based object recognition that reasons about the functionality of an object's intuitive parts. We extend the popular "recognition by parts" shape recognition framework to support "recognition by functional parts," by combining a set of functional primitives and their relations with a set of abstract volumetric shape primitives and their relations. Previous approaches have relied on more global object features, often ignoring the problem of object segmentation and thereby restricting themselves to range images of unoccluded scenes. We show how these shape primitives and relations can be easily recovered from superquadric ellipsoids which, in turn, can be recovered from either range or intensity images of occluded scenes, Furthermore, the proposed framework supports both unexpected (bottom-up) object recognition and expected (top-down) object recognition, We demonstrate the approach on a simple domain by recognizing a restricted class of hand-tools from 2-D images.
203665251
Understanding Object Motion of Tools and Vehicles.
29950481
Graphbots: Mobility in Discrete Spaces
Most previous theoretical work on motion planning has addressed the problem of path planning for geometrically simple robots in geometrically simple regions of Euclidean space (e.g., a planar region containing polygonal obstacles). In this paper we define a natural version of the motion planning problem in a graph theoretic setting. We establish conditions under which a “robot” or team of robots having a particular graph structure can move from any start location to any goal destination in a graph-structured space.
14801189
Understanding object motion
Many types of common objects, such as tools and vehicles, usually move in simple ways when they are wielded or driven: the natural axes of the object tend to remain aligned with the local trihedron defined by the object's trajectory. Based on this observation we use a model called Frenet-Serret motion which corresponds to the motion of a moving trihedron along a space curve. Knowing how the Frenet-Serret frame is changing relative to the observer gives us essential information for understanding the object's motion. This is illustrated here for four examples, involving tools (a wrench and a saw) and vehicles (an accelerating van, a turning taxi).
40896374
Qualitative description of camera motion from histograms of normal flow
If we histogram the normal flow vectors in images of a scene viewed by a moving observer, we can use the time-varying histogram to derive qualitative information about the observer's motion-for example, whether it is (primarily) translational or rotational, and whether the direction of translation or axis of rotation is (roughly) parallel or perpendicular to the camera axis. This is illustrated using flow histogram obtained from a variety of real image sequences.
20372308
Navigational Functionalities
206614039
Array Grammars
This tutorial briefly introduces array grammars, in which rewriting rules involve replacement of subarrays by subarrays. Strings can be regarded as one-dimensional arrays; but as we shall see, in higher dimensions special problems arise. In this tutorial we consider only the twodimensional case, but the extension to arbitrary dimensions is straightforward. A more detailed review of array grammars of various types, as well as the corresponding types of array acceptors, can be found in [1]. Array grammars (like string grammars) can be regarded as a class of graph grammars, but it seems more natural to regard them as rewriting systems of a special type.
189885505
Digital geometry
1884675
Fuzzy end nodes in fuzzy graphs
We define a fuzzy end node in a fuzzy graph, and show that no node can be both a cut node and a fuzzy end node. In a fuzzy tree, every node is either a cut node or a fuzzy end node, but the converse is not true. We also show that any nontrivial fuzzy tree has at least two fuzzy end nodes, and we characterize fuzzy cycles that have no cut nodes or no fuzzy end nodes.
16184629
Digital straightness
A digital arc is called ‘straight’ if it is the digitization of a straight line segment. Since the concept of digital straightness was introduced in the mid-1970’s, dozens of papers on the subject have appeared; many characterizations of digital straight lines have been formulated, and many algorithms for determining whether a digital arc is straight have been defined. This paper reviews the literature on digital straightness and discusses its relationship to other concepts of geometry, the theory of words, and number theory.
46687960
Web Grammars