A novel curve segmentation algorithm for determining control points for deformable-model-based target tracking is proposed. The algorithm is parameterless enabling a fully-fledged automated tracking regardless of the ...
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A novel curve segmentation algorithm for determining control points for deformable-model-based target tracking is proposed. The algorithm is parameterless enabling a fully-fledged automated tracking regardless of the shape of the object being tracked. Compared with other curve segmentation algorithms, it selects a minimal number of control points that yet deliver a superior shape description. The algorithm is comparatively tested with other curve segmentation algorithms in a variety of characteristic target outlines.
A novel paradigm for the synthesis of convergent-axis stereo geometries is presented. This paradigm incorporates constraints that represent task-oriented properties that can be easily derived in many applications of s...
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A novel paradigm for the synthesis of convergent-axis stereo geometries is presented. This paradigm incorporates constraints that represent task-oriented properties that can be easily derived in many applications of stereo-ranging, particularly those involving manipulation. Given these properties, a solution that selects the set of optimal design parameters, in the sense of accuracy, under the given constraints is presented. Results of this algorithm are discussed and analyzed in terms of the optimality of the minimum-area technique used in the derivation.
Programmable vector fields can be used to control a variety of flexible planar parts feeders. When a part is placed on our devices, the programmed vector field induces a force and moment upon it. Over time, the part m...
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Programmable vector fields can be used to control a variety of flexible planar parts feeders. When a part is placed on our devices, the programmed vector field induces a force and moment upon it. Over time, the part may come to rest in a dynamic equilibrium state. We demonstrate lower bounds on what the devices cannot do, and results on a classification of control strategies. We suggest sufficient conditions for programmable fields to induce well-behaved equilibria on every part placed on our devices. We define composition operators to build complex strategies from simple ones, and show the resulting fields are also well-behaved. We discuss whether fields outside this class can be useful and free of pathology. Using these tools, we describe new manipulation algorithms, and improve existing planning algorithms by a quadratic factor, and the plan-length by a linear factor. We relax earlier dynamic and mechanical assumptions to obtain more robust and flexible strategies. Finally, we consider parts feeders that can only implement a very limited "vocabulary" of vector fields. We discuss the trade-off between mechanical complexity and planning complexity.
This paper proposes a method of 3-dimensional measurement of a planar surface by using two fixed light sources and a TV camera. A set of two images is recorded by the camera switching on each light alternately. The pe...
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This paper proposes a method of 3-dimensional measurement of a planar surface by using two fixed light sources and a TV camera. A set of two images is recorded by the camera switching on each light alternately. The peak of the luminance distribution in each image is detected, and the orientation and distance of the planar surface are calculated. The position of the peak of a luminance distribution can be estimated accurately by using an image processing. The light sources can be conventional apparatus with no particular structure. The method is simple and suitable for a vision system on an indoor mobile robot.
In the emerging paradigm of animate vision, the visual processes are not thought of as being independent of cognitive or motor processing, but as an integrated system within the context of visual behavior. Intimate co...
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In the emerging paradigm of animate vision, the visual processes are not thought of as being independent of cognitive or motor processing, but as an integrated system within the context of visual behavior. Intimate coupling of sensory and motor systems have found to improve significantly the performance of behavior based vision systems. In order to study active vision systems one requires sensory-motor systems. Designing, building, and operating such a test bed is a challenging task. In this paper we describe the status of on-going work in developing a sensory-motor robotic system, R2H, with ten degrees of freedoms (DOF) for research in active vision. To complement the R2H system a Graphical Simulation and Animation (GSA) environment is also developed. The objective of building the GSA system is to create a comprehensive design tool to design and study the behavior of active systems and their interactions with the environment. GSA system aids the researchers to develop high performance and reliable software and hardware in a most effective manner. The GSA environment integrates sensing and motor actions and features complete kinematic simulation of the R2H system, it's sensors and it's workspace. With the aid of the GSA environment a Depth from Focus (DFF), Depth from Vergence, and Depth from Stereo modules are implemented and tested. The power and usefulness of the GSA system as a research tool is demonstrated by acquiring and analyzing images in the real and virtual worlds using the same software implemented and tested in the virtual world.
Texture is an important cue in region-based segmentation of images. In this paper, we provide insight into the development of a new set of distortion-invariant texture operators. These ''circular-Mellin'&#...
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Texture is an important cue in region-based segmentation of images. In this paper, we provide insight into the development of a new set of distortion-invariant texture operators. These ''circular-Mellin'' operators are invariant to both scale and orientation of the target and represent the spectral decomposition of the image scene in the polar-log coordinate system. Coupled with the unique shift invariance property of the correlator architecture, we show that these circular-Mellin operators can be used for rotation-and scale-invariant feature extraction. We note that while these feature extractors have a functional form that is similar to the Gabor operators, they have distortion-invariant characteristics unlike the Gabor functions that make them more suitable for texture segmentation. A detailed analytical description of these operators and segmentation results to highlight their salient properties are presented.
A necessary goal in the calibration of any instrument is an indication of how well the particular device performs. In the specific case where a camera system is used in the process of three-dimensional reconstruction ...
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A necessary goal in the calibration of any instrument is an indication of how well the particular device performs. In the specific case where a camera system is used in the process of three-dimensional reconstruction or stereopsis, geometric measures of the accuracy, precision, and repeatability of 3-D point measurements give a quantitative evaluation of the success of that algorithm. This paper presents an experimental performance analysis of a traditional calibration algorithm as applied to the problem of three-dimensional vision. The study begins with an analysis of the algorithm in a single camera or monocular system. Monocular analysis concludes with a derivation of error boundaries under different. geometric constraints. Showing how this residual error propagates from the component monocular systems into a three-dimensional reconstruction, a binocular analysis derives the desired performance monitors. The paper concludes with a geometric interpretation of the results.
The authors wish to organize furniture in a room with a team of robots that can push objects. The authors show how coordinated pushing by robots can change the pose (position and orientation) of objects and then they ...
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The authors wish to organize furniture in a room with a team of robots that can push objects. The authors show how coordinated pushing by robots can change the pose (position and orientation) of objects and then they ask whether planning, global control, and explicit communication are necessary for cooperatively changing the pose of objects. The authors answer in the negative and present, as witnesses, four cooperative manipulation protocols that use different amounts of state, sensing, and communication. The authors analyze these protocols in the information invariant framework. The authors formalize the notion of resource tradeoffs for robot protocols and give the tradeoffs for the specific protocols discussed here.
This paper shows that categorical color developed in Yue Du (1994) is a good representation of color space for some robot vision tasks. The authors use SCARF as a test case to compare 'equivalent' RGB, categor...
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This paper shows that categorical color developed in Yue Du (1994) is a good representation of color space for some robot vision tasks. The authors use SCARF as a test case to compare 'equivalent' RGB, categorical color, and intensity robot vision algorithms on a difficult robot road following task. SCARF uses a full three-dimensional representation of color space to formulate road and off-road colors. Performing categorical color or intensity projection, the authors can model the road and off-road colors as single dimensional probability density functions. This greatly reduces the time to process the color image. Moreover, the authors show that categorical color is a good representation in that it outperforms an equivalent intensity algorithm on the robot tasks. Categorical color, while it cannot outperform the original RGB algorithm, performs well enough to be used in this particular robot application. Its effectiveness is verified by many experiments on difficult road image sequences.
The system proposed in this paper uses active deformable models to track pedestrians moving in dynamic real-world scenes. First, figure pixels are separated from a fixed or slowly evolving ground image. Then, an initi...
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The system proposed in this paper uses active deformable models to track pedestrians moving in dynamic real-world scenes. First, figure pixels are separated from a fixed or slowly evolving ground image. Then, an initial segmentation process identifies interesting pixel blobs for tracking. The output of the segmentation process is used to choose the starting position of the control points of the active deformable model. Once tracking has begun, the control points are updated at frame rates by minimizing an energy function involving the relative position of model points, image data, and the characteristics of figure pixels.
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