In this paper, steps of the physically-based modeling technique are revisited. Proposals for enhancing computational burden are implemented. Force derived from the distance between the model profile and the object pro...
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ISBN:
(纸本)0819423068;9780819423061
In this paper, steps of the physically-based modeling technique are revisited. Proposals for enhancing computational burden are implemented. Force derived from the distance between the model profile and the object profile has proven sufficient for shape recovery purposes while the speed of the fitting process is reduced dramatically. In order to give machines the ability to detect surface irregularities as well as their sizes, a threshold potential function force is applied to excite the surface nodal mesh with good time requirements. Implementation details as well as sample examples are introduced.
Based on the concept of object- and behavior-oriented stereo vision, a method is introduced which enables a robot manipulator to handle two distinct types of objects. It uses an uncalibrated stereo vision system and a...
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ISBN:
(纸本)0819423068;9780819423061
Based on the concept of object- and behavior-oriented stereo vision, a method is introduced which enables a robot manipulator to handle two distinct types of objects. It uses an uncalibrated stereo vision system and allows a direct transition from image coordinates to motion control commands of a robot. An object can be placed anywhere in the robot's 3D work space which is in the field of view of both cameras. The objects to be manipulated can either be of flat cylindrical or elongate shape. Results gained from real-world experiments are discussed.
Augmented reality is a term used to describe systems in which computer-generated information is superimposed on top of the real world; for example, through the use of a see-through head-mounted display. A human user o...
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ISBN:
(纸本)0819423068;9780819423061
Augmented reality is a term used to describe systems in which computer-generated information is superimposed on top of the real world; for example, through the use of a see-through head-mounted display. A human user of such a system could still see and interact with the real world, but have valuable additional information, such as descriptions of important features or instructions for performing physical tasks, superimposed on the world. For example, the computer could identify and overlay them with graphic outlines, labels, and schematics. The graphics are registered to the real-world objects and appear to be 'painted' onto those objects. Augmented reality systems can be used to make productivity aids for tasks such as inspection, manufacturing, and navigation. One of the most critical requirements for augmented reality is to recognize and locate real-world objects with respect to the person's head. Accurate registration is necessary in order to overlay graphics accurately on top of the real-world objects. At the Colorado School of Mines, we have developed a prototype augmented reality system that uses head-mounted cameras and computervisiontechniques to accurately register the head to the scene. The current system locates and tracks a set of pre-placed passive fiducial targets placed on the real-world objects. The system computes the pose of the objects and displays graphics overlays using a see-through head-mounted display. This paper describes the architecture of the system and outlines the computervisiontechniques used.
A camera system to be used in a tactile vision aid for blind persons has been built and tested. The camera is based on individual adaptive photoreceptors modelled after the biological example and realized in standard ...
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ISBN:
(纸本)0819423068;9780819423061
A camera system to be used in a tactile vision aid for blind persons has been built and tested. The camera is based on individual adaptive photoreceptors modelled after the biological example and realized in standard CMOS technology. The system exhibits a large dynamic range of approximately 7 orders of magnitude in incident light intensity and a pronounced capability to detect moving objects. It is planned to connect such a camera to a set of mechanical actuators which will transmit processed information about the image to the skin of a person. This paper describes simulations and measurements carried out with single adaptive pixels as well as results obtained with two complete prototype camera systems.
Our goal is to match primitives of a pair of images, thereby solving the correspondence problem, in order to estimate depths of 3D scene points from the relative distance between matched features. We propose a feature...
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ISBN:
(纸本)0819423068;9780819423061
Our goal is to match primitives of a pair of images, thereby solving the correspondence problem, in order to estimate depths of 3D scene points from the relative distance between matched features. We propose a feature-based approach to solve the correspondence problem by minimizing an appropriate energy function where constraints on radiometric similarity and projective geometric invariance of coplanar points are defined. The method can be seen as a correlation based approach which takes into account the projective invariance of coplanar points in computing the optimal matches.
The ability to assess the severity of dermatoses by measuring the area of involvement is important in both clinical practice and research, but it has been shown that physicians, nurses and other groups are unable to d...
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ISBN:
(纸本)0819423068
The ability to assess the severity of dermatoses by measuring the area of involvement is important in both clinical practice and research, but it has been shown that physicians, nurses and other groups are unable to do this accurately. A common practice in current use is the 'rule of nine' method, but wide variations have been found between observers' estimates. The purpose of this work was to test and demonstrate the feasibility of a computervision technique for measuring the area of involvement in skin diseases by developing a system for psoriasis area assessment from slides which can be operated in an image processing environment. The exact percentage of the slide area involved varied from 1% to 59%, thus providing realistic material for the system. The system proved sufficiently accurate, and the techniques evidently have a potential for inclusion as parts of a more accurate and rapid method for area measurement in the case of skin diseases.
A special case of civilian active vision has been investigated here, namely, a vision system by car anti-fog headlamps. A method to estimate the light-engineering criteria for headlamp performances and simulate the op...
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ISBN:
(纸本)0819423068;9780819423061
A special case of civilian active vision has been investigated here, namely, a vision system by car anti-fog headlamps. A method to estimate the light-engineering criteria for headlamp performances and simulate the operation of the system through a turbid medium, such as fog, is developed on the base of the analytical procedures of the radiative transfer theory. This method features in include the spaced light source and receiver of a driver's active vision system, the complicated azimuth-nonsymmetrical emissive pattern of the headlamps, and the fine angular dependence of the fog phase function near the backscattering direction. The final formulas are derived in an analytical form providing additional convenience and simplicity for the computations. The image contrast of a road object with arbitrary orientation, dimensions, and shape and its limiting visibility range are studied as a function of meteorological visibility range in fog as well as of various emissive pattern, mounting, and adjustment parameters of the headlamps. Optimization both light-engineering and geometrical characteristics of the headlamps is shown to be possible to enable the opportunity to enhance the visibility range and, hence, traffic safety.
We discuss the uniqueness of 3-D shape recovery of a polyhedron from a single shading image, and propose an approach to uniquely determine the concave shape solution by using interreflections as a constraint. We show ...
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ISBN:
(纸本)0819423068
We discuss the uniqueness of 3-D shape recovery of a polyhedron from a single shading image, and propose an approach to uniquely determine the concave shape solution by using interreflections as a constraint. We show that if interreflection distribution is not considered, multiple convex (or concave) shape solutions usually exist for a pyramid with three or more visible facets. However, if interreflection distribution is used as a constraint to limit the shape of polyhedron (for a concave polyhedron), polyhedral shape can be uniquely determined. Interreflections, which were considered to be deleterious in conventional approaches, are an important constraint for shape-from-shading.
Oue goal is to mar ch primitives of a pair of images, thereby solving the correspondence problem, in order to estimate depths of 3D scene points from the relative distance (disparity) between matched features. We prop...
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ISBN:
(纸本)0819423068
Oue goal is to mar ch primitives of a pair of images, thereby solving the correspondence problem, in order to estimate depths of 3D scene points from the relative distance (disparity) between matched features. We propose a feature-based approach to solve the correspondence problem by minimizing an appropriate energy function where constraints on radiometric similarity and projective geometric invariance of coplanar points are defined. The method can be seen as a correlation based approach which take into account the projective invariance of coplanar points in computing the optimal matches.
This paper proposes a new localization method for indoor mobile robots. Using two cameras and one laser range finder on board a TRC mobile robot, the initial position and pose of the robot can be obtained by multisens...
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ISBN:
(纸本)0819423068;9780819423061
This paper proposes a new localization method for indoor mobile robots. Using two cameras and one laser range finder on board a TRC mobile robot, the initial position and pose of the robot can be obtained by multisensor fusion and scene matching based on geometric hashing. No correspondence calculation and special pattern recognition are needed during the scene matching. This localization method can be implemented in five stages: 1) Model the indoor environment. Some selected indoor environment features are firstly modeled off-line into hashing tables. 2) Perform system calibration and information fusion from two cameras and the range finder. 3) Extract the vertical edge points corresponding to the horizontal scanning plane of the 2D laser range finder from the scene images and transform them into geometric invariants. 4) Perform scene matching and matching verification by geometric hashing and model back-projection method respectively. 5) Perform position and pose estimation by a least square fit method. Experimental results show that the accuracy and reliability of this localization method are quite high.
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