Attentional mechanisms for socially interactive robots – a survey

This review intends to provide an overview of the state of the art in the modeling and implementation of automatic attentional mechanisms for socially interactive robots. Humans assess and exhibit intentionality by resorting to multisensory processes that are deeply rooted within low-level automatic attention-related mechanisms of the brain. For robots to engage with humans properly, they should also be equipped with similar capabilities. Joint attention, the precursor of many fundamental types of social interactions, has been an important focus of research in the past decade and a half, therefore providing the perfect backdrop for assessing the current status of state-of-the-art automatic attentional-based solutions. Consequently, we propose to review the influence of these mechanisms in the context of social interaction in cutting-edge research work on joint attention. This will be achieved by summarizing the contributions already made in these matters in robotic cognitive systems research, by identifying the main scientific issues to be addressed by these contributions and analyzing how successful they have been in this respect, and by consequently drawing conclusions that may suggest a roadmap for future successful research efforts

Computational and Robotic Models of Early Language Development: A Review

We review computational and robotics models of early language learning and development. We first explain why and how these models are used to understand better how children learn language. We argue that they provide concrete theories of language learning as a complex dynamic system, complementing traditional methods in psychology and linguistics. We review different modeling formalisms, grounded in techniques from machine learning and artificial intelligence such as Bayesian and neural network approaches. We then discuss their role in understanding several key mechanisms of language development: cross-situational statistical learning, embodiment, situated social interaction, intrinsically motivated learning, and cultural evolution. We conclude by discussing future challenges for research, including modeling of large-scale empirical data about language acquisition in real-world environments. Keywords: Early language learning, Computational and robotic models, machine learning, development, embodiment, social interaction, intrinsic motivation, self-organization, dynamical systems, complexity.Comment: to appear in International Handbook on Language Development, ed. J. Horst and J. von Koss Torkildsen, Routledg

Visual Attention for Robotic Cognition: A Biologically Inspired Probabilistic Architecture

The human being, the most magnificent autonomous entity in the universe, frequently takes the decision of `what to look at' in their day-to-day life without even realizing the complexities of the underlying process. When it comes to the design of such an attention system for autonomous robots, all of a sudden this apparently simple task appears to be an extremely complex one with highly dynamic interaction among motor skills, knowledge and experience developed throughout the life-time, highly connected circuitry of the visual cortex, and super-fast timing. The most fascinating thing about visual attention system of the primates is that the underlying mechanism is not precisely known yet. Different influential theories and hypothesis regarding this mechanism, however, are being proposed in psychology and neuroscience. These theories and hypothesis have encouraged the research on synthetic modeling of visual attention in computer vision, computational neuroscience and, very recently, in AI robotics. The major motivation behind the computational modeling of visual attention is two-fold: understanding the mechanism underlying the cognition of the primates' and using the principle of focused attention in different real-world applications, e.g. in computer vision, surveillance, and robotics. Accordingly, we observe the rise of two different trends in the computational modeling of visual attention. The first one is mostly focused on developing mathematical models which mimic, as much as possible, the details of the primates' attention system: the structure, the connectivity among visual neurons and different regions of the visual cortex, the flow of information etc. Such models provide a way to test the theories of the primates' visual attention with minimal involvement from the live subjects. This is a magnificent way to use technological advancement for the understanding of human cognition. The second trend in computational modeling, on the other hand, uses the methodological sophistication of the biological processes (like visual attention) to advance the technology. These models are mostly concerned with developing a technical system of visual attention which can be used in real-world applications where the principle of focused attention might play a significant role for redundant information management. This thesis is focused on developing a computational model of visual attention for robotic cognition and, therefore, belongs to the second trend. The design of a visual attention model for robotic systems as a component of their cognition comes with a number of challenges which, generally, do not appear in the traditional computer vision applications of visual attention. The robotic models of visual attention, although heavily inspired by the rich literature of visual attention in computer vision, adopt different measures to cope with these challenges. This thesis proposes a Bayesian model of visual attention designed specifically for robotic systems and, therefore, tackles the challenges involved with robotic visual attention. The operation of the proposed model is guided by the theory of biased competition, a popular theory from cognitive neuroscience describing the mechanism of primates' visual attention. The proposed Bayesian attention model offers a robot-centric approach of visual attention where the head-pose of a robot in the 3D world is estimated recursively such that the robot can focus on the most behaviorally relevant stimuli in its environment. The behavioral relevance of an object determined based on two criteria which are inspired by the postulates of the biased competitive hypothesis of visual attention in the primates. Accordingly, the proposed model encourages a robot to focus on novel stimuli or stimuli that have similarity with a `sought for' object depending on the context. In order to address a number of robot-specific issues of visual attention, the proposed model is further extended to the multi-modal case where speech commands from the human are used to modulate the visual attention behavior of the robot. The Bayes model of visual attention, inherited from the Bayesian sensor fusion characteristic, naturally accommodates multi-modal information during attention selection. This enables the proposed model to be the core component of an attention oriented speech-based human-robot interaction framework. Extensive experiments are performed in the real-world to investigate different aspects of the proposed Bayesian visual attention model

Computer vision based behavior analysis

Ankara : The Department of Electrical and Electronics Engineering and the Institute of Engineering and Science of Bilkent University, 2009.Thesis (Ph. D.) -- Bilkent University, 2009.Includes bibliographical references leaves 111-124.In this thesis, recognition and understanding of behavior based on visual inputs and automated decision schemes are investigated. Behavior analysis is carried out on a wide scope ranging from animal behavior to human behavior. Due to this extensive coverage, we present our work in two main parts. Part I of the thesis investigates locomotor behavior of lab animals with particular focus on drug screening experiments, and Part II investigates analysis of behavior in humans, with specific focus on visual attention. The animal behavior analysis method presented in Part I, is composed of motion tracking based on background subtraction, determination of discriminative behavioral characteristics from the extracted path and speed information, summarization of these characteristics in terms of feature vectors and classification of feature vectors. The experiments presented in Part I indicate that the proposed animal behavior analysis system proves very useful in behavioral and neuropharmacological studies as well as in drug screening and toxicology studies. This is due to the superior capability of the proposed method in detecting discriminative behavioral alterations in response to pharmacological manipulations. The human behavior analysis scheme presented in Part II proposes an efficient method to resolve attention fixation points in unconstrained settings adopting a developmental psychology point of view. The head of the experimenter is modeled as an elliptic cylinder. The head model is tracked using Lucas-Kanade optical flow method and the pose values are estimated accordingly. The resolved poses are then transformed into the gaze direction and the depth of the attended object through two Gaussian regressors. The regression outputs are superposed to find the initial estimates for object center locations. These estimates are pooled to mimic human saccades realistically and saliency is computed in the prospective region to determine the final estimates for attention fixation points. Verifying the extensive generalization capabilities of the human behavior analysis method given in Part II, we propose that rapid gaze estimation can be achieved for establishing joint attention in interaction-driven robot communication as well.Yücel, ZeynepPh.D

A Bayesian hierarchy for robust gaze estimation in human–robot interaction

In this text, we present a probabilistic solution for robust gaze estimation in the context of human–robot interaction. Gaze estimation, in the sense of continuously assessing gaze direction of an interlocutor so as to determine his/her focus of visual attention, is important in several important computer vision applications, such as the development of non-intrusive gaze-tracking equipment for psychophysical experiments in neuroscience, specialised telecommunication devices, video surveillance, human–computer interfaces (HCI) and artificial cognitive systems for human–robot interaction (HRI), our application of interest. We have developed a robust solution based on a probabilistic approach that inherently deals with the uncertainty of sensor models, but also and in particular with uncertainty arising from distance, incomplete data and scene dynamics. This solution comprises a hierarchical formulation in the form of a mixture model that loosely follows how geometrical cues provided by facial features are believed to be used by the human perceptual system for gaze estimation. A quantitative analysis of the proposed framework's performance was undertaken through a thorough set of experimental sessions. Results show that the framework performs according to the difficult requirements of HRI applications, namely by exhibiting correctness, robustness and adaptiveness

The Future of Humanoid Robots

This book provides state of the art scientific and engineering research findings and developments in the field of humanoid robotics and its applications. It is expected that humanoids will change the way we interact with machines, and will have the ability to blend perfectly into an environment already designed for humans. The book contains chapters that aim to discover the future abilities of humanoid robots by presenting a variety of integrated research in various scientific and engineering fields, such as locomotion, perception, adaptive behavior, human-robot interaction, neuroscience and machine learning. The book is designed to be accessible and practical, with an emphasis on useful information to those working in the fields of robotics, cognitive science, artificial intelligence, computational methods and other fields of science directly or indirectly related to the development and usage of future humanoid robots. The editor of the book has extensive R&D experience, patents, and publications in the area of humanoid robotics, and his experience is reflected in editing the content of the book

A reinforcement-learning model of top-down attention based on a potential-action map.

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