1,721,005 research outputs found
Discovery and recognition of motion primitives in human activities
Full text linkWe present a novel framework for the automatic discovery and recognition of motion primitives in videos of human activities. Given the 3D pose of a human in a video, human motion primitives are discovered by optimizing the ‘motion flux’, a quantity which captures the motion variation of a group of skeletal joints. A normalization of the primitives is proposed in order to make them invariant with respect to a subject anatomical variations and data sampling rate. The discovered primitives are unknown and unlabeled and are unsupervisedly collected into classes via a hierarchical non-parametric Bayes mixture model. Once classes are determined and labeled they are further analyzed for establishing models for recognizing discovered primitives. Each primitive model is defined by a set of learned parameters. Given new video data and given the estimated pose of the subject appearing on the video, the motion is segmented into primitives, which are recognized with a probability given according to the parameters of the learned models. Using our framework we build a publicly available dataset of human motion primitives, using sequences taken from well-known motion capture datasets. We expect that our framework, by providing an objective way for discovering and categorizing human motion, will be a useful tool in numerous research fields including video analysis, human inspired motion generation, learning by demonstration, intuitive human-robot interaction, and human behavior analysis
3D multi-robot patrolling with a two-level coordination strategy
Full text linkTeams of UGVs patrolling harsh and complex 3D environments can experience interference and spatial conflicts with one another. Neglecting the occurrence of these events crucially hinders both soundness and reliability of a patrolling process. This work presents a distributed multi-robot patrolling technique, which uses a two-level coordination strategy to minimize and explicitly manage the occurrence of conflicts and interference. The first level guides the agents to single out exclusive target nodes on a topological map. This target selection relies on a shared idleness representation and a coordination mechanism preventing topological conflicts. The second level hosts coordination strategies based on a metric representation of space and is supported by a 3D SLAM system. Here, each robot path planner negotiates spatial conflicts by applying a multi-robot traversability function. Continuous interactions between these two levels ensure coordination and conflicts resolution. Both simulations and real-world experiments are presented to validate the performances of the proposed patrolling strategy in 3D environments. Results show this is a promising solution for managing spatial conflicts and preventing deadlocks
Visual search and recognition for robot task execution and monitoring
Full text linkVisual search of relevant targets in the environment is a crucial robot skill. We propose a preliminary framework for the execution monitor of a robot task, taking care of the robot attitude to visually searching the environment for targets involved in the task. Visual search is also relevant to recover from a failure. The framework exploits deep reinforcement learning to acquire a common sense scene structure and it takes advantage of a deep convolutional network to detect objects and relevant relations holding between them. The framework builds on these methods to introduce a vision-based execution monitoring, which uses classical planning as a backbone for task execution. Experiments show that with the proposed vision-based execution monitor the robot can complete simple tasks and can recover from failures in autonomy
Gabor 3D
No full textEducação Superior::Ciências Exatas e da Terra::MatemáticaUma Gabor 3D é o produto de uma gaussiana 3D com uma função 3D harmônica, onde o comprimento dos eixos é controlado pela gaussiana e a frequência é controlada pela função harmônica. Superfícies 3D de Gabor são usadas para análise do espaço-temporal de um sinal tridimensional, como uma sequência de vídeo, para extrair características da energia de moviment
Gabor 3D
No full textEducação Superior::Ciências Exatas e da Terra::MatemáticaUma Gabor 3D é o produto de uma gaussiana 3D com uma função 3D harmônica, onde o comprimento dos eixos é controlado pela gaussiana e a frequência é controlada pela função harmônica. Superfícies 3D de Gabor são usadas para análise do espaço-temporal de um sinal tridimensional, como uma sequência de vídeo, para extrair características da energia de moviment
Gabor 3D
No full textEducação Superior::Ciências Exatas e da Terra::MatemáticaUma Gabor 3D é o produto de uma gaussiana 3D com uma função 3D harmônica, onde o comprimento dos eixos é controlado pela gaussiana e a frequência é controlada pela função harmônica. Superfícies 3D de Gabor são usadas para análise do espaço-temporal de um sinal tridimensional, como uma sequência de vídeo, para extrair características da energia de moviment
Gabor 3D
No full textEducação Superior::Ciências Exatas e da Terra::MatemáticaUma Gabor 3D é o produto de uma gaussiana 3D com uma função 3D harmônica, onde o comprimento dos eixos é controlado pela gaussiana e a frequência é controlada pela função harmônica. Superfícies 3D de Gabor são usadas para análise do espaço-temporal de um sinal tridimensional, como uma sequência de vídeo, para extrair características da energia de moviment
Augmenting Situation Awareness via Model-Based Control in Rescue Robot
No full textAugmenting Situation Awareness via Model-Based Control in Rescue Robo
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