The challenging task of automated handling of variable objects necessitates a combination of innovative engineering and advanced information technology. This paper describes the application of a recently developed con...
详细信息
ISBN:
(纸本)0819423068;9780819423061
The challenging task of automated handling of variable objects necessitates a combination of innovative engineering and advanced information technology. This paper describes the application of a recently developed control strategy applied to overcome some limitations of robot handling, particularly when dealing with variable objects. The paper focuses on a novel approach to accommodate the need for sensing and actuation in controlling the pickup procedure. An experimental robot-based system for the handling of soft parts, ranging from artificial components to natural objects such as fruit and meat pieces was developed. The configuration comprises a modular gripper subsystem, and an industrial robot as part of a distributed control system. The gripper subsystem features manually configurable fingers with integrated sensing capabilities. The control architecture is based on a concept of decentralized control differentiating between positioning and gripping procedures. In this way, the robot and gripper systems are treated as individual handling operations. THis concept allows very short set-up times for future changes involving one or more sub-systems.
The term 'active vision' was first used by Bajcsy at a NATO workshop in 1982 to describe an emerging field of robot vision which departed sharply from traditional paradigms of image understanding and machine v...
详细信息
ISBN:
(纸本)0819423068;9780819423061
The term 'active vision' was first used by Bajcsy at a NATO workshop in 1982 to describe an emerging field of robot vision which departed sharply from traditional paradigms of image understanding and machine vision. The new approach embeds a moving camera platform as an in-the-loop component of robotic navigation or hand-eye coordination. Visually served steering of the focus of attention supersedes the traditional functions of recognition and gaging. Custom active vision platforms soon proliferated in research laboratories in Europe and North America. In 1990 the National Science Foundation funded the design of a common platform to promote cooperation and reduce cost in active vision research. This paper describes the resulting platform. The design was driven by payload requirements for binocular motorized C-mount lenses on a platform whose performance and articulation emulate those of the human eye-head system. The result was a 4-DOF mechanisms driven by servo controlled DC brush motors. A crossbeam supports two independent worm-gear driven camera vergence mounts at speeds up to 1,000 degrees per second over a range of ± 90 degrees from dead ahead. This crossbeam is supported by a pan-tilt mount whose horizontal axis intersects the vergence axes for translation-free camera rotation about these axes at speeds up to 500 degrees per second.
This paper focuses on simulating a model of 3D-color vision system based on synthetic nonlinear modulation. The model is set up to recover 3D and color properties from a colored object through evaluating several rf-in...
详细信息
ISBN:
(纸本)0819423068;9780819423061
This paper focuses on simulating a model of 3D-color vision system based on synthetic nonlinear modulation. The model is set up to recover 3D and color properties from a colored object through evaluating several rf-interferograms sampled by a black-white CCD camera. Colorizing a black-white CCD camera in a 3D-vision system implies high resolution. The synthetic nonlinear modulation is different from other 3D-color vision systems. Different colored lights are synchronously modulated with characterizing rf-frequencies to detect a 3D object. Recovering colors is equally treated as recovering 3D information. Optical filters are not used. Instead, a suitable algorithm is adopted for recovering color and 3D information. Since a modulated optical rf-signal is used as a detecting probe rather than an unmodulated optical wave, higher orders of harmonic signals may be caused by electrical or optical components. Although linear matching techniques are adapted to prevent the problem, it is necessary to simulate the vision system for predicting its performances. An 8-bit black-white CCD camera with different signal to noise ratios is taken as an example in the simulation. 3D color properties are evaluated for the system in the case of nonlinearity and noise. An optimized result is obtained for realizing this vision system.
Biologically plausible model of the system with an adaptive behavior in a priori environment and resistant to impairment has been developed. The system consists of input, learning, and output subsystems. The first sub...
详细信息
ISBN:
(纸本)0819423068;9780819423061
Biologically plausible model of the system with an adaptive behavior in a priori environment and resistant to impairment has been developed. The system consists of input, learning, and output subsystems. The first subsystems classifies input patterns presented as n-dimensional vectors in accordance with some associative rule. The second one being a neural network determines adaptive responses of the system to input patterns. Arranged neural groups coding possible input patterns and appropriate output responses are formed during learning by means of negative reinforcement. Output subsystem maps a neural network activity into the system behavior in the environment. The system developed has been studied by computer simulation imitating a collision-free motion of a mobile robot. After some learning period the system 'moves' along a road without collisions. It is shown that in spite of impairment of some neural network elements the system functions reliably after relearning. Foveal visual preprocessor model developed earlier has been tested to form a kind of visual input to the system.
A new feature space trajectory (FST) description of 3D distorted views of an object is advanced for active vision applications. In an FST, different distorted object views are vertices in feature space. A new eigen-fe...
详细信息
ISBN:
(纸本)0819423068;9780819423061
A new feature space trajectory (FST) description of 3D distorted views of an object is advanced for active vision applications. In an FST, different distorted object views are vertices in feature space. A new eigen-feature space and Fourier transform features are used. Vertices for different adjacent distorted views are connected by straight lines so that an FST is created as the viewpoint changes. Each different object is represented by a distinct FST. An object to be recognized is represented as a point in feature space; the closest FST denotes the class of the object, and the closest line segment on the FST indicates its pose. A new neural network is used to efficiently calculate distances. We discuss its uses in active vision. Apart from an initial estimate of object class and pose, the FST processor can specify where to move the sensor to: confirm class and pose, to grasp the object, or to focus on a specific object part for assembly or inspection. We advance initial remarks on the number of aspect views needed and which aspect views are needed to represent an object. We note the superiority of our eigenspace for discrimination, how it can provide shift invariance, and how the FST overcomes problems associated with other classifiers.
Active vision is identified by a closed loop linking sensing with acting. Thus, an active vision system's behavior is directly determined by what it senses. To date however, the responses produced by active vision...
详细信息
ISBN:
(纸本)0819423068;9780819423061
Active vision is identified by a closed loop linking sensing with acting. Thus, an active vision system's behavior is directly determined by what it senses. To date however, the responses produced by active vision systems have tended to be relatively low-level, generally designed to facilitate improved sensing, by enhancing the duration or speed of object tracking, for example, or optimizing the focused application of more intensive image processing. This is probably adequate if the active vision system is designed as a front end to other processes or to specialized application systems, or if it is a demonstration in support of a theoretical vision model. However, this leaves unanswered the problems of i) how to select an appropriate action when many different alternatives are available, and ii) how best to modify the behavioral repertoire of the system. These problems are especially important in two situations: firstly, when an autonomous system faces a novel situation and must respond adaptively without the benefit of a priori knowledge, and secondly, when systems attempt higher levels of perception and response, and links between the absolute properties of the incoming image data and the actual objects of perception become increasingly attenuated. This paper discusses methods for linking learning with active vision so that the behavior of the system is optimized over time for the achievement of goals. We argue the necessity of system goals in learning vision systems, and discuss methods for propagating goals through all levels of loose hierarchies. In the last section we outline an architecture in which high and low level perception operate interactively and in parallel.
Three-dimensional (3D) reconstruction of highly textured surfaces on unvegetated (rock-like) terrain is of major interest for stereo vision based mapping applications. We describe a prototype system for automatic mode...
详细信息
ISBN:
(纸本)0819423068
Three-dimensional (3D) reconstruction of highly textured surfaces on unvegetated (rock-like) terrain is of major interest for stereo vision based mapping applications. We describe a prototype system for automatic modeling of such scenes. It is based on two frame CCD cameras, which are tightly attached to each other ensuring constant relative orientation. One camera is used to acquire known reference points to get the exterior orientation of the system, the other records the surface images. The system is portable to keep image acquisition as short as possible. Automatic calibration using the images acquired by the calibration camera permits the computation of exterior orientation parameters of the surface camera via a transformation matrix. A robust matching method providing dense disparities together with a flexible reconstruction algorithm renders an accurate grid of 3D points on arbitrarily shaped surfaces. The results of several stereo reconstructions are merged. Projection onto the global shape allows easy evaluation of volumes, and thematic mapping with respect to the desired surface geometry in construction processes. We report on accuracy and emphasize on the practical usage. It is shown that the prototype system is able to generate a proper data set of surface descriptions that is accurate and dense enough to serve as documentation, planning and accounting basis.
Active vision is identified by a closed loop linking sensing with acting. Thus, an active vision system's behaviour is directly determined by what it senses. To date however, the responses produced by active visio...
详细信息
ISBN:
(纸本)0819423068
Active vision is identified by a closed loop linking sensing with acting. Thus, an active vision system's behaviour is directly determined by what it senses. To date however, the responses produced by active vision systems have tended to be relatively low-level, generally designed to facilitate improved sensing, by enhancing the duration or speed of object tracking, for example, or optimising the focussed application of more intensive image processing. This is probably adequate if the active vision system is designed as a front end to other processes or to specialised application systems, or if it is a demonstration in support of a theoretical vision model. However, this leaves unanswered the problems of i) how to select an appropriate action when many different alternatives are available, and ii) how best to modify the behavioural repertoire of the system. These problems are especially important in two situations: firstly, when an autonomous system faces a novel situation and must respond adaptively without the benefit of a priori knowledge, and secondly, when systems attempt higher levels of perception and response, and links between the absolute properties of the incoming image data and the actual objects of perception become increasingly attenuated. This paper discusses methods for linking learning with active vision so that the behaviour of the system is optimised over time for the achievement of goals. We argue the necessity of system goals in learning vision systems, and discuss methods for propagating goals through all levels of loose hierarchies. In the last section we outline an architecture in which high and low level perception operate interactively and in parallel.
Feature point tracking from an image sequence is an important step in many methods of image understanding including shape from motion and mobile robot navigation. Assuming an affine camera model, this paper proposed a...
详细信息
ISBN:
(纸本)0819423068;9780819423061
Feature point tracking from an image sequence is an important step in many methods of image understanding including shape from motion and mobile robot navigation. Assuming an affine camera model, this paper proposed a new tracking method using affine invariance. Any 3D feature point can have unique coordinates with reference to an affine basis and the affine coordinates are invariant to affine transformation: camera rotations and translations. The images of a set of 4 control points defining an affine basis are tracked in an image sequence using a conventional method. Under this assumption, given a feature point in any image, its locus in the first image is a straight line. The straight lines of the corresponding features from the image sequence will intersect at a point, the corresponding feature point, in the first image. A Hough transform technique is designed to detect this intersection point and track the corresponding feature points in the image sequence. This technique is suitable for tracking a large number of feature points. Its performance is practically unaffected by missing features in some images and large motion steps. Accurate and reliable results had been obtained in real experiments using the method.
Automated unmanned guided vehicles have many potential applications in manufacturing, medicine, space and defense. A mobile robot has been designed for the 1996 Automated Unmanned Vehicle Society competition which was...
详细信息
ISBN:
(纸本)0819423068;9780819423061
Automated unmanned guided vehicles have many potential applications in manufacturing, medicine, space and defense. A mobile robot has been designed for the 1996 Automated Unmanned Vehicle Society competition which was held in Orlando, Florida on July 15, 1996. The competition required the vehicle to follow solid and dashed lines around an approximately 800 ft. path while avoiding obstacles, overcoming terrain changes such as inclines and sand traps, and attempting to maximize speed. The purpose of this paper is to describe the algorithm developed for the line following. The line following algorithm images two windows and locates their centroid and with the knowledge that the points are on the ground plane, a mathematical and geometrical relationship between the image coordinates of the points and their corresponding ground coordinates are established. The angle of the line and minimum distance from the robot centroid are then calculated and used in the steering control. Two cameras are mounted on the robot with a camera on each side. One camera guides the robot and when it loses track of the line on its side, the robot control system automatically switches to the other camera. The test bed system has provided an educational experience for all involved and permits understanding and extending the state of the art in autonomous vehicle design.
暂无评论