Rail inspection is a very important task in railway maintenance for traffic safety issues and in preventing dangerous situations. Monitoring railway infrastructure is an important aspect in which the periodical inspection of rail rolling... more
Rail inspection is a very important task in railway maintenance for traffic safety issues and in preventing dangerous situations. Monitoring railway infrastructure is an important aspect in which the periodical inspection of rail rolling plane is required. Up to the present days the inspection of the railroad is operated manually by trained personnel. A human operator walks along the rail
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... Sequences A.Branca, G.Cicirelli, E. Stella, A. Distante Istituto Elaboraxione Segnali ed Immagini - CNR 70126 BAR1 - Italy Abstract ... 28, No. 2,199 5. [20] D.Marr, T.Poggio, A computational theory of human stereo vision, Proc. of... more
... Sequences A.Branca, G.Cicirelli, E. Stella, A. Distante Istituto Elaboraxione Segnali ed Immagini - CNR 70126 BAR1 - Italy Abstract ... 28, No. 2,199 5. [20] D.Marr, T.Poggio, A computational theory of human stereo vision, Proc. of Royal Society of London B, Vo1.204. ...
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The goal of the work is to propose a method to solve with visual means the problem of underwater navigation of an autonomous vehicle moving in deep sea in order to perform inspection of a pipe positioned near the ocean floor. We refer to... more
The goal of the work is to propose a method to solve with visual means the problem of underwater navigation of an autonomous vehicle moving in deep sea in order to perform inspection of a pipe positioned near the ocean floor. We refer to the ability of an autonomous system to determine its motion with respect to the environment. It
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Self-location is the capability of a mobile robot to determine its position in the environment referring to absolute landmarks. The possibility to use natural visual landmarks for self-location augments the autonomy and the flexibility of... more
Self-location is the capability of a mobile robot to determine its position in the environment referring to absolute landmarks. The possibility to use natural visual landmarks for self-location augments the autonomy and the flexibility of mobile vehicles. In this paper the use of junctions, detected in real images, as landmarks is proposed. The use of visual cues means that problems
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Detecting unexpected obstacles and avoiding collisions is an important task for any autonomous mobile robot. In this paper we describe an approach using a sonar-based system that we have used in our indoor autonomous mobile system. The... more
Detecting unexpected obstacles and avoiding collisions is an important task for any autonomous mobile robot. In this paper we describe an approach using a sonar-based system that we have used in our indoor autonomous mobile system. The logical design of this system is shown, followed by a description of how it builds a knowledge of the environment. The information collected
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In this paper, an accurate range sensor for the three-dimensional reconstruction of environments is designed and developed. Following the principles of laser profilometry, the device exploits a set of optical transmitters able to project... more
In this paper, an accurate range sensor for the three-dimensional reconstruction of environments is designed and developed. Following the principles of laser profilometry, the device exploits a set of optical transmitters able to project a laser line on the environment. A high-resolution and high-frame-rate camera assisted by a telecentric lens collects the laser light reflected by a parabolic mirror, whose shape is designed ad hoc to achieve a maximum measurement error of 10 mm when the target is placed 3 m away from the laser source. Measurements are derived by means of an analytical model, whose parameters are estimated during a preliminary calibration phase. Geometrical parameters, analytical modeling and image processing steps are validated through several experiments, which indicate the capability of the proposed device to recover the shape of a target with high accuracy. Experimental measurements show Gaussian statistics, having standard deviation of 1.74 mm within the measur...
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Many of visual navigation strategies for an autonomous mobile robot are landmark based. A vehicle to determine its position needs to refer to absolute references in the environment, so landmarks are required to be invariant for rotation,... more
Many of visual navigation strategies for an autonomous mobile robot are landmark based. A vehicle to determine its position needs to refer to absolute references in the environment, so landmarks are required to be invariant for rotation, translation, scale and perspective. A straightforward alternative is to be able to characterize invariantly the context where landmarks are placed. In this paper, we show as a neural network appropriately trained, is able to recognize context where landmarks are located in the scene. The early results seem to be interesting.
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ABSTRACT
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ABSTRACT During last years, Computer Vision has developed algorithms for most of early vision processes. It is a common idea that each vision process seaparatly cannot supply a reliable descritpion of the scene. In fact, one of the keys... more
ABSTRACT During last years, Computer Vision has developed algorithms for most of early vision processes. It is a common idea that each vision process seaparatly cannot supply a reliable descritpion of the scene. In fact, one of the keys in reliability and robustness of biological systems is their ability to integrate information from different early processes. The base concept of our vision system is to integrate information from stereo and shading (Fig.1). The results obtained from this scheme in previous works are very interesting and suggest us to continue on this methodology. In the first work 1.2 the base approach to integration scheme was presented. The work deals on general concepts and main evolutions on shading analysis, in terms of analysis simplifications and improved accuracy. The scheme was tested on both synthetical and real scenes.
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ABSTRACT In the last few decades, virtual reconstruction of objects has grown interest in the field of quality control. As known, smart manufactures need automatic systems for the real-time investigation of production yields, i.e.... more
ABSTRACT In the last few decades, virtual reconstruction of objects has grown interest in the field of quality control. As known, smart manufactures need automatic systems for the real-time investigation of production yields, i.e. techniques, methods and technologies devoted to the analysis of quality. In particular, high-resolution systems are required for the measurement of surface profiles aimed to the detection and characterization of small defects, with sizes reaching the limit of few microns. This book Chapter describes the procedure for the design of high-resolution and high-accuracy laser scanning probes based on triangulation techniques for the exhaustive reconstruction of objects. Drawbacks and limitations will be discussed, with particular focus on occlusion problems due to possible undercut surfaces within the testing objects. A complete description of novel techniques will be thus provided together with a demonstration of a resulting optical probe. Challenging metal objects, namely drilling tools, will be then investigated, proving measurement resolutions close to the physical diffraction limit.
This paper describes a technique for detection of unknown obstacles using a stereo pair of TV cameras, for mobile robot navigational purpose. Three-dimensional information is recovered by matching segments. Moreover a feature grouping... more
This paper describes a technique for detection of unknown obstacles using a stereo pair of TV cameras, for mobile robot navigational purpose. Three-dimensional information is recovered by matching segments. Moreover a feature grouping technique is used to produce a coarse obstacle reconstruction, but enough for detecting the free space (without obstacles) in the environment. The advantage is to use a such reconstructed obstacle map is twofold: higher resolution than map obtained by active sensors such as ultrasonics and, moreover, the obstacles are detected from far than active sensors. Results on experimental stereo images, acquired in our laboratory, are presented in order to illustrate the reliability of the technique.
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... Texture Analysis for Shadow Removing in Video-surveill~ance Systems" Alessandro Leone Cosimo Distante Nicola Ancona Ettore Stella Pietro Siciliano IMM IMM ISSIA ISSIA IMM CNR CNR CNR CNR CNR Lecce, Italy... more
... Texture Analysis for Shadow Removing in Video-surveill~ance Systems" Alessandro Leone Cosimo Distante Nicola Ancona Ettore Stella Pietro Siciliano IMM IMM ISSIA ISSIA IMM CNR CNR CNR CNR CNR Lecce, Italy Lecce, Italy Ban, Italy Ban, Italy Lecce, Italy ...
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... 317, 1985 Page 5. [2] D. Marr, T. Poggio, A Theory of human stereo vision , (3) TO Binford, Inferring surface from images , Art. Zntell., ... 17, p. 205, 1981 [5] MT Chiaradia, A. Distante, R. Mugnuolo, E. Stella, Sur-face... more
... 317, 1985 Page 5. [2] D. Marr, T. Poggio, A Theory of human stereo vision , (3) TO Binford, Inferring surface from images , Art. Zntell., ... 17, p. 205, 1981 [5] MT Chiaradia, A. Distante, R. Mugnuolo, E. Stella, Sur-face recovering by local shading analysis , Proc. 5th Int. Conf. ...
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a 2-D Hopfield neural network has been used to perform the shortest path task for optimal routing in a packet switched network. The optimum routing problem requires finding the shortest path in a graph as a sub-task. This optimization... more
a 2-D Hopfield neural network has been used to perform the shortest path task for optimal routing in a packet switched network. The optimum routing problem requires finding the shortest path in a graph as a sub-task. This optimization problem can be solved using the Hopfield neural model (an interesting alternative to classical optimization techniques), strongly sensitive to the tuning
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ABSTRACT Considers the problems of finding the location and orientation of a mobile robot using an image taken by a CCD camera carried by the robot. The naturally occurring landmarks used are the corners of the room extracted from the... more
ABSTRACT Considers the problems of finding the location and orientation of a mobile robot using an image taken by a CCD camera carried by the robot. The naturally occurring landmarks used are the corners of the room extracted from the line image of the 3D indoor scene. The location and orientation of the vehicle is calculated by perspective information of the landmarks in the scene of the room where the robot moves. This system and some experiments to demonstrate the performance of its components are described
ABSTRACT In this paper we are going to describe an ongoing research project intended to integrate a full vision system in a flexible robot programming environment. The use of the vision system sensors, allows the robot to derive a... more
ABSTRACT In this paper we are going to describe an ongoing research project intended to integrate a full vision system in a flexible robot programming environment. The use of the vision system sensors, allows the robot to derive a description of the work cell. This description is used for the collision avoidance problem of robot manipulators. The work cell in assembly context can include moving objects. Without any previous knowledge of the work space, the vision system thus immediately determines the work cell map in its entirely. Successively this map is used as input for the path planner process to find the collision-free path. During the assembly robot operation, the vision system is activated to reflect any changes in the robot environment. In this way the path planner works recursively, updating the collision free path until the goal is reached.
ABSTRACT Low-level navigation for autonomous vehicles can be accomplished efficiently by a behavioral-based approach that involves the simultaneous execution of independent sub-tasks seen as primitive behaviors. Each behavior maps sensory... more
ABSTRACT Low-level navigation for autonomous vehicles can be accomplished efficiently by a behavioral-based approach that involves the simultaneous execution of independent sub-tasks seen as primitive behaviors. Each behavior maps sensory data into control commands in a reactive way, with no need of internal representations. A useful tool for realizing such a direct mapping is fuzzy logic, that allows the production of control rules by either manual programming or automatic learning. In prospect of implementing an articulated control system including all the low-level behaviors of navigation, this paper focuses on the problem of obtaining an efficient and robust fuzzy controller performing a single behavior and presents a method for minimizing the number of rules of a fuzzy controller developed for driving a TRC Labmate based vehicle along the wall on its right-hand side. Fuzzy rules, that map ultrasonic sensor readings onto steering velocity values, are learned automatically from training data collected during operator-driven runs of the vehicle. In addition, we address the problem of defining an appropriate performance function, that may be useful for evaluating the influence of the rule base reduction on the overall behavior of the vehicle during navigation, but also for estimating the quality of a control rule, in order to adapt rules on- line. Results of an experimental comparison between the original fuzzy wall-follower and its optimized version are reported.
ABSTRACT 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... more
ABSTRACT 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.
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ABSTRACT Navigation in dynamic indoor environments requires a mobile vehicle to follow the planned path while avoiding unexpected obstacles eventually met along it. In this paper an attempt of designing a path planar using a computational... more
ABSTRACT Navigation in dynamic indoor environments requires a mobile vehicle to follow the planned path while avoiding unexpected obstacles eventually met along it. In this paper an attempt of designing a path planar using a computational model suitable for fast implementation on special purpose hardware is presented, in which the automatic modeling of the scene and its continuous updating are accomplished by means of a recursive ultrasonic-based obstacle avoidance system. From this model a graph representing all the possible paths for the robot in the free-space is built using well known methodologies (configuration space, generalized cones). The task of searching for the shortest path in this graph is solved by means of a neural network based on the Hopfield model, that represents an interesting alternative to classical techniques as A*. A major advantage of this neural approach is the parallel nature of the resulting network that allows a rapid convergence to a solution when implemented in hardware. Simulation results are shown to illustrate the performance of the Hopfield path planner.
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Mobile robot navigation seen as trail following is the most industrial exploited implementation of autonomous vehicles. Normally, expensive magnetic trail are used. In this paper a cheaper odour trail is proposed. In fact, a vehicle... more
Mobile robot navigation seen as trail following is the most industrial exploited implementation of autonomous vehicles. Normally, expensive magnetic trail are used. In this paper a cheaper odour trail is proposed. In fact, a vehicle equipped with two odour sensors is able to follow a felt ribbon soaked with odour marker. The advantage of use of this technology is the
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... 28 ,No. 2,1995. [5] D.Marr,T.Poggio, A computational theory of hu-man stereo uision, Proc. of Royal Society of Lon-don B, Vo1.204. ... BMVC95. [9] A-Branca, E.Stella, G.Attolico, AT)istante, Fea-ture matching by optimization using... more
... 28 ,No. 2,1995. [5] D.Marr,T.Poggio, A computational theory of hu-man stereo uision, Proc. of Royal Society of Lon-don B, Vo1.204. ... BMVC95. [9] A-Branca, E.Stella, G.Attolico, AT)istante, Fea-ture matching by optimization using cnuii*onmental conatraints Proc. 5th Int. Work. ...