153 research outputs found

    Humanoid visual attention and gaze control

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    Towards adaptive and autonomous humanoid robots: from vision to actions

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    Although robotics research has seen advances over the last decades robots are still not in widespread use outside industrial applications. Yet a range of proposed scenarios have robots working together, helping and coexisting with humans in daily life. In all these a clear need to deal with a more unstructured, changing environment arises. I herein present a system that aims to overcome the limitations of highly complex robotic systems, in terms of autonomy and adaptation. The main focus of research is to investigate the use of visual feedback for improving reaching and grasping capabilities of complex robots. To facilitate this a combined integration of computer vision and machine learning techniques is employed. From a robot vision point of view the combination of domain knowledge from both imaging processing and machine learning techniques, can expand the capabilities of robots. I present a novel framework called Cartesian Genetic Programming for Image Processing (CGP-IP). CGP-IP can be trained to detect objects in the incoming camera streams and successfully demonstrated on many different problem domains. The approach requires only a few training images (it was tested with 5 to 10 images per experiment) is fast, scalable and robust yet requires very small training sets. Additionally, it can generate human readable programs that can be further customized and tuned. While CGP-IP is a supervised-learning technique, I show an integration on the iCub, that allows for the autonomous learning of object detection and identification. Finally this dissertation includes two proof-of-concepts that integrate the motion and action sides. First, reactive reaching and grasping is shown. It allows the robot to avoid obstacles detected in the visual stream, while reaching for the intended target object. Furthermore the integration enables us to use the robot in non-static environments, i.e. the reaching is adapted on-the- fly from the visual feedback received, e.g. when an obstacle is moved into the trajectory. The second integration highlights the capabilities of these frameworks, by improving the visual detection by performing object manipulation actions

    Fast and robust image feature matching methods for computer vision applications

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    Service robotic systems are designed to solve tasks such as recognizing and manipulating objects, understanding natural scenes, navigating in dynamic and populated environments. It's immediately evident that such tasks cannot be modeled in all necessary details as easy as it is with industrial robot tasks; therefore, service robotic system has to have the ability to sense and interact with the surrounding physical environment through a multitude of sensors and actuators. Environment sensing is one of the core problems that limit the deployment of mobile service robots since existing sensing systems are either too slow or too expensive. Visual sensing is the most promising way to provide a cost effective solution to the mobile robot sensing problem. It's usually achieved using one or several digital cameras placed on the robot or distributed in its environment. Digital cameras are information rich sensors and are relatively inexpensive and can be used to solve a number of key problems for robotics and other autonomous intelligent systems, such as visual servoing, robot navigation, object recognition, pose estimation, and much more. The key challenges to taking advantage of this powerful and inexpensive sensor is to come up with algorithms that can reliably and quickly extract and match the useful visual information necessary to automatically interpret the environment in real-time. Although considerable research has been conducted in recent years on the development of algorithms for computer and robot vision problems, there are still open research challenges in the context of the reliability, accuracy and processing time. Scale Invariant Feature Transform (SIFT) is one of the most widely used methods that has recently attracted much attention in the computer vision community due to the fact that SIFT features are highly distinctive, and invariant to scale, rotation and illumination changes. In addition, SIFT features are relatively easy to extract and to match against a large database of local features. Generally, there are two main drawbacks of SIFT algorithm, the first drawback is that the computational complexity of the algorithm increases rapidly with the number of key-points, especially at the matching step due to the high dimensionality of the SIFT feature descriptor. The other one is that the SIFT features are not robust to large viewpoint changes. These drawbacks limit the reasonable use of SIFT algorithm for robot vision applications since they require often real-time performance and dealing with large viewpoint changes. This dissertation proposes three new approaches to address the constraints faced when using SIFT features for robot vision applications, Speeded up SIFT feature matching, robust SIFT feature matching and the inclusion of the closed loop control structure into object recognition and pose estimation systems. The proposed methods are implemented and tested on the FRIEND II/III service robotic system. The achieved results are valuable to adapt SIFT algorithm to the robot vision applications

    Facial expression imitation for human robot interaction

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    Master'sMASTER OF ENGINEERIN

    Image Feature Information Extraction for Interest Point Detection: A Comprehensive Review

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    Interest point detection is one of the most fundamental and critical problems in computer vision and image processing. In this paper, we carry out a comprehensive review on image feature information (IFI) extraction techniques for interest point detection. To systematically introduce how the existing interest point detection methods extract IFI from an input image, we propose a taxonomy of the IFI extraction techniques for interest point detection. According to this taxonomy, we discuss different types of IFI extraction techniques for interest point detection. Furthermore, we identify the main unresolved issues related to the existing IFI extraction techniques for interest point detection and any interest point detection methods that have not been discussed before. The existing popular datasets and evaluation standards are provided and the performances for eighteen state-of-the-art approaches are evaluated and discussed. Moreover, future research directions on IFI extraction techniques for interest point detection are elaborated

    Development of a foveated vision system for the tracking of mobile targets in dynamic environments

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    Mestrado em Engenharia MecânicaEste trabalho descreve um sistema baseado em percepção activa e em visão foveada, projectado para identificar e seguir objectos móveis em ambientes dinâmicos. O sistema inclui uma unidade pan & tilt para facilitar o seguimento e manter o objecto no centro do campo visual das câmaras, cujas lentes grandeangular e tele-objectiva proporcionam uma visão periférica e foveada do mundo, respectivamente. O método Haar features é utilizado para efectuar o reconhecimento dos objectos. O algoritmo de seguimento baseado em template matching continua a perseguir o objecto mesmo quando este não mais está a ser reconhecido pelo módulo de identificação. Algumas técnicas utilizadas para melhorar o template matching são também apresentadas, nomeadamente o Filtro Gaussiano e a Computação Rápida de Filtro Gaussiano. São indicados resultados relativos ao seguimento, identificação e desempenho global do sistema. O sistema comporta-se muito bem, mantendo o processamento de, pelo menos, 15 fotogramas por segundo em imagens de 320x240, num computador portátil normal. São também abordados alguns aspectos para melhorar o desempenho do sistema. ABSTRACT: This work describes a system based on active perception and foveated vision, intended to identify and track moving targets in dynamic environments. The full system includes a pan and tilt unit to ease tracking and keep the interesting target in the two cameras’ view, whose wide / narrow field lenses provide both a peripheral and a foveal view of the world respectively. View-based Haar-like features are employed for object recognition. A template matching based tracking technique continues to track the object even when its view is not recognized by the object recognition module. Some of the techniques used to improve the template matching performance are also presented, namely Gaussian Filtering and Fast Gaussian computation. Results are presented for tracking, identification and global system’s operation. The system performs well up to 15 frames per second on a 320 x 240 image on an ordinary laptop computer. Several issues to improve the system’s performance are also addressed
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