University of Coimbra
ISR, DEEC,
In vision based systems used in mobile robotics and virtual reality systems the perception of self-motion and the structure of the environment is essential. Inertial and earth field magnetic pose sensors can provide valuable data about... more
In vision based systems used in mobile robotics and virtual reality systems the perception of self-motion and the structure of the environment is essential. Inertial and earth field magnetic pose sensors can provide valuable data about camera ego-motion, as well as absolute references for structure feature orientations. In this article we present several techniques running on a biologically inspired artificial system which attempts to recreate the "hardware" of biological visuovestibular systems resorting to computer vision and inertial-magnetic devices. More specifically, we explore the fusion of optical flow and stereo techniques with data from the inertial and magnetic sensors, enabling the depth flow segmentation of a moving observer. A depth map registration and motion segmentation method is proposed, and experimental results of stereo depth flow segmentation obtained from a moving robotic/artificial observer are presented.
- by João Filipe Ferreira and +1
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- Computer Vision, Perception, MEMS, Vestibular System
Three-dimensional surface reconstruction using a handheld scanner is a process with great potential for use on different fields of research, commerce and industrial production. In this article we will describe the evolution of a project... more
Three-dimensional surface reconstruction using a handheld scanner is a process with great potential for use on different fields of research, commerce and industrial production. In this article we will describe the evolution of a project comprising the study and development of a system that implements the aforementioned process based on two-dimensional images. We will present our current work on the development of a fully portable, handheld system using cameras, projected structured light and attitude and positioning measuring sensors -the Tele-3D scanner.
In this text we present the real-time implementation of a Bayesian framework for robotic multisensory perception on a graphics processing unit (GPU) using the Compute Unified Device Architecture (CUDA). As an additional objective, we... more
In this text we present the real-time implementation of a Bayesian framework for robotic multisensory perception on a graphics processing unit (GPU) using the Compute Unified Device Architecture (CUDA). As an additional objective, we intend to show the benefits of parallel computing for similar problems (i.e. probabilistic grid-based frameworks), and the user-friendly nature of CUDA as a programming tool. Inspired by the study of biological systems, several Bayesian inference algorithms for artificial perception have been proposed. Their high computational cost has been a prohibitory factor for realtime implementations. However in some cases the bottleneck is in the large data structures involved, rather than the Bayesian inference per se. We will demonstrate that the SIMD (single-instruction, multiple-data) features of GPUs provide a means for taking a complicated framework of relatively simple and highly parallelisable algorithms operating on large data structures, which might take up to several minutes of execution with a regular CPU implementation, and arrive at an implementation that executes in the order of tenths of a second. The implemented multimodal perception module (including stereovision, binaural sensing and inertial sensing) builds an egocentric representation of occupancy and local motion, the Bayesian Volumetric Map (BVM), based on which gaze shift decisions are made to perform active exploration and reduce the entropy of the BVM. Experimental results show that the real-time implementation successfully drives the robotic system to explore areas of the environment mapped with high uncertainty.
In this text, we use a Bayesian framework for active multimodal perception of 3D structure and motion -which, while not strictly neuromimetic, finds its roots in the role of the dorsal perceptual pathway of the human brain -to implement a... more
In this text, we use a Bayesian framework for active multimodal perception of 3D structure and motion -which, while not strictly neuromimetic, finds its roots in the role of the dorsal perceptual pathway of the human brain -to implement a strategy of active exploration based on entropy. The computational models described in this text support a robotic implementation of multimodal active perception to be used in real-world applications, such as human-machine interaction or mobile robot navigation.
Robotic implementations of gaze control and image stabilization have been previously proposed, that rely on fusing inertial and visual sensing modalities. They are bioinspired in the sense that human and biological system also combine the... more
Robotic implementations of gaze control and image stabilization have been previously proposed, that rely on fusing inertial and visual sensing modalities. They are bioinspired in the sense that human and biological system also combine the two sensing modalities for the same goal. In this work we build upon these previous results and, with the contribution of psychophysical studies, attempt a more bio-mimetic approach to the robotic implementation. Since Bayesian models have been successfully used to explain psychophysical experimental findings, we propose a robotic implementation using Bayesian inference.
- by José Prado and +2
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- Robotics, Perception, Bayesian
In this text, we present a Bayesian framework for active multimodal perception of 3D structure and motion. The design of this framework finds its inspiration in the role of the dorsal perceptual pathway of the human brain. Its composing... more
In this text, we present a Bayesian framework for active multimodal perception of 3D structure and motion. The design of this framework finds its inspiration in the role of the dorsal perceptual pathway of the human brain. Its composing models build upon a common egocentric spatial configuration that is naturally fitting for the integration of readings from multiple sensors using a Bayesian approach. In the process, we will contribute with efficient and robust probabilistic solutions for cyclopean geometry-based stereovision and auditory perception based only on binaural cues, modelled using a consistent formalisation that allows their hierarchical use as building blocks for the multimodal sensor fusion framework. We will explicitly or implicitly address the most important challenges of sensor fusion using this framework, for vision, audition and vestibular sensing. Moreover, interaction and navigation requires maximal awareness of spatial surroundings, which in turn is obtained through active attentional and behavioural exploration of the environment. The computational models described in this text will support the construction of a simultaneously flexible and powerful robotic implementation of multimodal active perception to be used in real-world applications, such as human-machine interaction or mobile robot navigation.
In this text, we present a Bayesian framework for active multimodal perception of 3D structure and motion. The design of this framework finds its inspiration in the role of the dorsal perceptual pathway of the human brain. Its composing... more
In this text, we present a Bayesian framework for active multimodal perception of 3D structure and motion. The design of this framework finds its inspiration in the role of the dorsal perceptual pathway of the human brain. Its composing models build upon a common egocentric spatial configuration that is naturally fitting for the integration of readings from multiple sensors using a Bayesian approach. In the process, we will contribute with efficient and robust probabilistic solutions for cyclopean geometry-based stereovision and auditory perception based only on binaural cues, modelled using a consistent formalisation that allows their hierarchical use as building blocks for the multimodal sensor fusion framework. We will explicitly or implicitly address the most important challenges of sensor fusion using this framework, for vision, audition and vestibular sensing. Moreover, interaction and navigation requires maximal awareness of spatial surroundings, which in turn is obtained through active attentional and behavioural exploration of the environment. The computational models described in this text will support the construction of a simultaneously flexible and powerful robotic implementation of multimodal active perception to be used in real-world applications, such as human-machine interaction or mobile robot navigation.
In this text we will formalise a novel solution, the Bayesian Volumetric Map (BVM), as a framework for a metric, short-term, egocentric spatial memory for multimodal perception of 3D structure and motion. This solution will enable the... more
In this text we will formalise a novel solution, the Bayesian Volumetric Map (BVM), as a framework for a metric, short-term, egocentric spatial memory for multimodal perception of 3D structure and motion. This solution will enable the implementation of top-down mechanisms of attention guidance of perception towards areas of high entropy/uncertainty, so as to promote active exploration of the environment by the robotic perceptual system. In the process, we will to try address the inherent challenges of visual, auditory and vestibular sensor fusion through the BVM. In fact, it is our belief that perceptual systems are unable to yield truly useful descriptions of their environment without resorting to a temporal series of sensory fusion processed on a short-term memory such as the BVM.
- by Pierre Bessiere and +2
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- Perception, Bayesian, Spatial Memory, Multimodal Perception
This paper explores the combination of inertial sensor data with vision. Visual and inertial sensing are two sensory modalities that can be explored to give robust solutions on image segmentation and recovery of 3D structure from images,... more
This paper explores the combination of inertial sensor data with vision. Visual and inertial sensing are two sensory modalities that can be explored to give robust solutions on image segmentation and recovery of 3D structure from images, increasing the capabilities of autonomous robots and enlarging the application potential of vision systems. In biological systems, the information provided by the vestibular system is fused at a very early processing stage with vision, playing a key role on the execution of visual movements such as gaze holding and tracking, and the visual cues aid the spatial orientation and body equilibrium. In this paper, we set a framework for using inertial sensor data in vision systems, and describe some results obtained. The unit sphere projection camera model is used, providing a simple model for inertial data integration. Using the vertical reference provided by the inertial sensors, the image horizon line can be determined. Using just one vanishing point and the vertical, we can recover the camera's focal distance and provide an external bearing for the system's navigation frame of reference. Knowing the geometry of a stereo rig and its pose from the inertial sensors, the collineation of level planes can be recovered, providing enough restrictions to segment and reconstruct vertical features and leveled planar patches.
- by Jorge Lobo
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This paper describes a prototype of an inertial navigation system for use in mobile land vehicles, such as cars or mobile robots. The complete system is composed by sensors, their mechanical mount and cabling, these connect to a PC card... more
This paper describes a prototype of an inertial navigation system for use in mobile land vehicles, such as cars or mobile robots. The complete system is composed by sensors, their mechanical mount and cabling, these connect to a PC card with local processing and memory, based on a Intel 80C196KC microcontroller.
This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations. The rotation between the camera and the inertial sensor can be... more
This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations. The rotation between the camera and the inertial sensor can be estimated, when calibrating the camera, by having both sensors observe the vertical direction, using a vertical chessboard target and gravity. The translation between the two can be estimated using a simple passive turntable and static images, provided that the system can be adjusted to turn about the inertial sensor null point in several poses. Simulation and real data results are presented to show the validity and simple requirements of the proposed method.
This paper explores the combination of inertial sensor data with vision. Visual and inertial sensing are two sensory modalities that can be explored to give robust solutions on image segmentation and recovery of 3D structure from images,... more
This paper explores the combination of inertial sensor data with vision. Visual and inertial sensing are two sensory modalities that can be explored to give robust solutions on image segmentation and recovery of 3D structure from images, increasing the capabilities of autonomous robots and enlarging the application potential of vision systems. In biological systems, the information provided by the vestibular system is fused at a very early processing stage with vision, playing a key role on the execution of visual movements such as gaze holding and tracking, and the visual cues aid the spatial orientation and body equilibrium. In this paper, we set a framework for using inertial sensor data in vision systems, and describe some results obtained. The unit sphere projection camera model is used, providing a simple model for inertial data integration. Using the vertical reference provided by the inertial sensors, the image horizon line can be determined. Using just one vanishing point and the vertical, we can recover the camera's focal distance and provide an external bearing for the system's navigation frame of reference. Knowing the geometry of a stereo rig and its pose from the inertial sensors, the collineation of level planes can be recovered, providing enough restrictions to segment and reconstruct vertical features and leveled planar patches.
Mobile robots can be an invaluable aid to human first responders (FRs) in catastrophic incidents, as they are expendable and can be used to reduce human exposure to risk in search and rescue (SaR) missions, as well as attaining a more... more
Mobile robots can be an invaluable aid to human first responders (FRs) in catastrophic incidents, as they are expendable and can be used to reduce human exposure to risk in search and rescue (SaR) missions, as well as attaining a more effective response. Moreover, parallelism and robustness yielded by multi-robot systems (MRS) may be very useful in this kind of spatially distributed tasks, which are distributed in space, providing augmented situation awareness (SA). However, this requires adequate cooperative behaviors, both within MRS teams and between human and robotic teams. Collaborative context awareness between both teams is crucial to assess information utility, efficiently share information and build a common and consistent SA. This paper presents the foreseen research within the CHOPIN research project, which aims to address these scientific challenges and provide a proof of concept for the cooperation between human and robotic teams in SaR scenarios.
- by Paulo Menezes and +4
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In this text we present the real-time implementation of a Bayesian framework for robotic multisensory perception on a graphics processing unit (GPU) using the Compute Unified Device Architecture (CUDA). As an additional objective, we... more
In this text we present the real-time implementation of a Bayesian framework for robotic multisensory perception on a graphics processing unit (GPU) using the Compute Unified Device Architecture (CUDA). As an additional objective, we intend to show the benefits of parallel computing for similar problems (i.e. probabilistic grid-based frameworks), and the user-friendly nature of CUDA as a programming tool. Inspired by the study of biological systems, several Bayesian inference algorithms for artificial perception have been proposed. Their high computational cost has been a prohibitory factor for realtime implementations. However in some cases the bottleneck is in the large data structures involved, rather than the Bayesian inference per se. We will demonstrate that the SIMD (single-instruction, multiple-data) features of GPUs provide a means for taking a complicated framework of relatively simple and highly parallelisable algorithms operating on large data structures, which might take up to several minutes of execution with a regular CPU implementation, and arrive at an implementation that executes in the order of tenths of a second. The implemented multimodal perception module (including stereovision, binaural sensing and inertial sensing) builds an egocentric representation of occupancy and local motion, the Bayesian Volumetric Map (BVM), based on which gaze shift decisions are made to perform active exploration and reduce the entropy of the BVM. Experimental results show that the real-time implementation successfully drives the robotic system to explore areas of the environment mapped with high uncertainty.
Robotic implementations of gaze control and image stabilization have been previously proposed, that rely on fusing inertial and visual sensing modalities. They are bioinspired in the sense that human and biological system also combine the... more
Robotic implementations of gaze control and image stabilization have been previously proposed, that rely on fusing inertial and visual sensing modalities. They are bioinspired in the sense that human and biological system also combine the two sensing modalities for the same goal. In this work we build upon these previous results and, with the contribution of psychophysical studies, attempt a more biomimetic approach to the robotic implementation. Since Bayesian models have been successfully used to explain psychophysical experimental findings, we propose a robotic implementation using Bayesian inference.
Three-dimensional surface reconstruction using a handheld scanner is a process with great potential for use on different fields of research, commerce and industrial production. In this article we will describe the evolution of a project... more
Three-dimensional surface reconstruction using a handheld scanner is a process with great potential for use on different fields of research, commerce and industrial production. In this article we will describe the evolution of a project comprising the study and development of a system that implements the aforementioned process based on two-dimensional images. We will present our current work on the development of a fully portable, handheld system using cameras, projected structured light and attitude and positioning measuring sensors -the Tele-3D scanner.
a b s t r a c t Humans excel in manipulation tasks, a basic skill for our survival and a key feature in our manmade world of artefacts and devices. In this work, we study how humans manipulate simple daily objects, and construct a... more
a b s t r a c t Humans excel in manipulation tasks, a basic skill for our survival and a key feature in our manmade world of artefacts and devices. In this work, we study how humans manipulate simple daily objects, and construct a probabilistic representation model for the tasks and objects useful for autonomous grasping and manipulation by
In vision based systems used in mobile robotics and virtual reality systems the perception of self-motion and the structure of the environment is essential. Inertial and earth field magnetic pose sensors can provide valuable data about... more
In vision based systems used in mobile robotics and virtual reality systems the perception of self-motion and the structure of the environment is essential. Inertial and earth field magnetic pose sensors can provide valuable data about camera ego-motion, as well as absolute references for structure feature orientations. In this article we present several techniques running on a biologically inspired artificial system which attempts to recreate the “hardware” of biological visuovestibular systems resorting to computer vision and inertial- ...
- by Jorge Dias and +1
- •
- Optical Flow, Mobile Robot, Motion Segmentation, Depth Map
This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations. The rotation between the camera and the inertial sensor can be... more
This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations. The rotation between the camera and the inertial sensor can be estimated, when calibrating the camera, by having both sensors observe the vertical direction, using a vertical chessboard target and gravity. The translation between the two can be estimated using a simple passive turntable and static images, provided that the system can be adjusted to turn about the inertial sensor null point in several poses. Simulation and real data results are presented to show the validity and simple requirements of the proposed method.
- by Jorge Dias and +1
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- Mechanical Engineering, Robotics, Computer Vision, Robotic