In this paper I will describe work in progress on a low cost vision-based robot designed to give primitive tours. The system is very simple, robust and efficient, and runs on a hardware platform which could be duplica...
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Most of the information regarding the shape of polyhedral objects is preserved in the edges and the vertices of these objects. Gray level images of scenes containing such objects are often processed to extract edge an...
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ISBN:
(纸本)0819413208
Most of the information regarding the shape of polyhedral objects is preserved in the edges and the vertices of these objects. Gray level images of scenes containing such objects are often processed to extract edge and vertex information to produce equivalent line sketches. An accurate line sketch of a scene serves as an effective input to high level vision systems concerned with scene understanding or object recognition. The performance of these systems is therefore greatly dependent on the accuracy of the line sketch. The work reported in this paper addresses the issues associated with generating accurate line sketches from gray level images. The methods described here have been implemented and tested with real and synthetic images and are compared to other vertex or corner detection techniques. The performance of the vertex detector is assessed using simulation runs on images with varied signal-to-noise ratios. The computational performance of this algorithm is evaluated and assessed by operating directly on the gray-scale image.
There has recently been growing interest in exploiting the concept of reasoning about function for object recognition. In a function-based approach to object recognition, recognition of an object means labeling it as ...
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ISBN:
(纸本)0819413208
There has recently been growing interest in exploiting the concept of reasoning about function for object recognition. In a function-based approach to object recognition, recognition of an object means labeling it as belonging to some category of objects according to the function that it could serve. The few function-based recognition systems which have so far been described in the literature have all assumed that the input to the problem is a pure static shape description. By `pure' shape we mean that the only object property that the systems have reasoned about is their abstract shape. By `static' shape we mean that the systems have reasoned about an object from only a single (assumed rigid) abstract shape instance. This paper discusses some of the issues which must be addressed in extending the function-based approach to handle non-shape properties (such as material properties) and dynamic shape descriptions.
This paper describes a fuzzy logic controller (FLC) designed and implemented to control the yaw angle of a 10 kW fixed speed teetered-rotor wind turbine presently being commissioned at the University of Texas at El Pa...
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ISBN:
(纸本)0819413208
This paper describes a fuzzy logic controller (FLC) designed and implemented to control the yaw angle of a 10 kW fixed speed teetered-rotor wind turbine presently being commissioned at the University of Texas at El Paso. The technical challenge of this project is that the wind turbine represents a highly stochastic nonlinear system. The problems associated with the wind turbine yaw control are of a similar nature as those experienced with position control of high inertia equipment like tracking antenna, gun turrets, and overhead cranes. Furthermore, the wind turbine yaw controller must be extremely cost-effective and highly reliable in order to be economically viable compared to the fossil fueled power generators.
We describe an implemented computer program that recognizes the occurrence of simple spatial motion events in simulated video input. The program receives an animated line-drawing as input and produces as output a sema...
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ISBN:
(纸本)0819413208
We describe an implemented computer program that recognizes the occurrence of simple spatial motion events in simulated video input. The program receives an animated line-drawing as input and produces as output a semantic representation of the events occurring in that movie. We suggest that the notions of support, contact, and attachment are crucial to specifying many simple spatial motion event types and present a logical notation for describing classes of events that incorporates such notions as primitives. We then suggest that the truth values of such primitives can be recovered from perceptual input by a process of counterfactual simulation, predicting the effect of hypothetical changes to the world on the immediate future. Finally, we suggest that such counterfactual simulation is performed using knowledge of naive physical constraints such as substantiality, continuity, gravity, and ground plane. We describe the algorithms that incorporate these ideas in the program and illustrate the operation of the program on sample input.
This paper describes a model based vision system that has been developed which is able to perform model based reasoning at real-time (or near real-time) rates and for which both the hardware and prototyping costs are ...
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ISBN:
(纸本)0819413208
This paper describes a model based vision system that has been developed which is able to perform model based reasoning at real-time (or near real-time) rates and for which both the hardware and prototyping costs are low. The basic approach taken is to extract a set of useful features from observed models using a library of feature primitive operators. Scale and orientation invariant combinations of these features are used as indices into a hardware lookup table to establish initial correspondence between similar combinations that will be encountered when examining unknown objects. When performing initial recognition of an unknown object, evidence for an object in a particular spatial pose is accumulated, giving rise to an initial set of hypotheses. The strongest hypotheses are then refined by iteratively hypothesizing new (previously uninstantiated) model/object feature matches and computing a confidence measure associated with the current instantiation set. If confidence increases the newly hypothesized instantiation is retained, otherwise it is discarded.
In many object recognition problems, the object to be identified is one of a fixed set (library) of objects. The problem of identifying which object is present then shares characteristics of the signal detection and p...
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ISBN:
(纸本)0819413208
In many object recognition problems, the object to be identified is one of a fixed set (library) of objects. The problem of identifying which object is present then shares characteristics of the signal detection and parameter estimation problem: which signal is present and what are its parameters? The Reciprocal Basis Set/Direction of Arrival (RBS/DOA) technique is a recently developed technique for object pose determination. It uses a single, comprehensive analytic object model representing a suite of views of an object. Object orientation can be directly established from single 2-D views of the object, without a costly search of the pose parameter space, and without need for the views to be related by a geometric image transformation. This paper describes how one can construct reciprocal basis sets to simultaneously determine object identity and pose from a single 2-D image. Results are presented which demonstrate this ability for a single unknown pose parameter using synthetic and camera-acquired images.
In this paper, a novel image analysis technique is proposed, which may be performed prior to coding in order to decide what is the most significant information to encode. In the proposed system, the image to be coded ...
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ISBN:
(纸本)0819413208
In this paper, a novel image analysis technique is proposed, which may be performed prior to coding in order to decide what is the most significant information to encode. In the proposed system, the image to be coded is first partitioned into a large number of sub-blocks of N*N pixels. The blocks can then be stored into two major classes according to the level of the visual activity present. The classification is based on analyzing the local histogram within each sub-block. In this paper, we initially analyze the image blocks to separate uniform blocks from those that can be classified as non-uniform blocks. Adjacent uniform blocks with the same statistics are merged to form large blocks. These blocks can then be coded by their mean values. It is also shown that the non-uniform blocks may also be classified into three categories with different levels of activity.
In this paper, a number of spatial/spatial-frequency image representations are reviewed. Wavelets have recently generated much interest, both in applied areas as well as in more theoretical ones. Wavelet transform rel...
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ISBN:
(纸本)0819413208
In this paper, a number of spatial/spatial-frequency image representations are reviewed. Wavelets have recently generated much interest, both in applied areas as well as in more theoretical ones. Wavelet transform relative to some basic wavelets provides a flexible time- frequency window which automatically narrows when observing high frequency phenomena and widens when studying low frequency environments. As a result, it is suitable for visual information representation. Applications in computervision such as image compression and image enhancement are examined. method is presented, in which, a N X N subimage is divided into a lot of N X 7 or N X 9 narrow image regions perpendicular to local fringe direction, and then each region is segmented by a corresponding threshold curve. Because the threshold curves can follow fringe's extremum changes, it can avoid the effect of the inhomogeneous grey level distribution caused by diffraction halo and accurate segmen space, a projection operator is used in the spatial-variant deconvolution. Nevertheless, experimental results show that this approximation mechanism can generate the depth map of different images successfully.
We have been exploring the hypothesis that vision is an explanatory process, in which causal and functional reasoning about potential motion plays an intimate role in mediating the activity of low-level visual process...
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ISBN:
(纸本)0819413208
We have been exploring the hypothesis that vision is an explanatory process, in which causal and functional reasoning about potential motion plays an intimate role in mediating the activity of low-level visual processes. In particular, we have explored two of the consequences of this view for the construction of purposeful vision systems: Causal and design knowledge can be used to (1) drive focus of attention, and (2) choose between ambiguous image interpretations. An important result of visual understanding is an explanation of the scene's causal structure: How action is originated, constrained, and prevented, and what will happen in the immediate future. In everyday visual experience, most action takes the form of motion, and most causal analysis takes the form of dynamical analysis. This is even true of static scenes, where much of a scene's interest lies in how possible motions are arrested. This paper describes our progress in developing domain theories and visual processes for the understanding of various kinds of structured scenes, including structures built out of children's constructive toys and simple mechanical devices.
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