Search results for "Signal and Image processing"
showing 10 items of 454 documents
Contribution of vibrational modalities for navigation in virtual environments
2016
The virtual environment navigation may induces the simulator sickness depending on conditions and user’s profile. The potential virtual reality multimodality may provide solutions to these problems while improving the sense of presence. In this context, the objective of this research is to determine what is the impact of vibrational modalities for navigation in virtual environments on the simulation.A taxonomy of navigation methods is proposed. It results in 4 types, specific egocentric, specific exocentric, abstract egocentric and abstract exocentric. First we simulate rumble strip vibrations during a driving simulation. The experimentation exposed that these vibrations make driver more aw…
Extraction of Airways from CT (EXACT'09)
2012
Contains fulltext : 107854.pdf (Publisher’s version ) (Open Access) This paper describes a framework for establishing a reference airway tree segmentation, which was used to quantitatively evaluate fifteen different airway tree extraction algorithms in a standardized manner. Because of the sheer difficulty involved in manually constructing a complete reference standard from scratch, we propose to construct the reference using results from all algorithms that are to be evaluated. We start by subdividing each segmented airway tree into its individual branch segments. Each branch segment is then visually scored by trained observers to determine whether or not it is a correctly segmented part o…
Registration of arbitrary multi-view 3D acquisitions
2013
International audience; To register 3D meshes representing smooth surfaces we track the 3D digitization system using photogrammetric techniques and calibrations. We present an example by digitizing a 800 mm x 600 mm portion of a car door. To increase the tracking accuracy the 3D scanner is placed in a cubic frame of side 0.5 m covered with 78 targets. The target frame moves in a volume that is approximately 1100 mm x 850 mm x 900 mm, to digitize the area of interest. Using four cameras this target frame is tracked with of an accuracy of 0.03 mm spatially and 0.180 mrad angularly. A registration accuracy between 0.1 mm and 2 mm is reached. This method can be used for the registration of mesh…
Night Thermal Unmixing for the Study of Microscale Surface Urban Heat Islands with TRISHNA-Like Data
2019
International audience; Urban Heat Islands (UHIs) at the surface and canopy levels are major issues in urban planification and development. For this reason, the comprehension and quantification of the influence that the different land-uses/land-covers have on UHIs is of particular importance. In order to perform a detailed thermal characterisation of the city, measures covering the whole scenario (city and surroundings) and with a recurrent revisit are needed. In addition, a resolution of tens of meters is needed to characterise the urban heterogeneities. Spaceborne remote sensing meets the first and the second requirements but the Land Surface Temperature (LST) resolutions remain too rough…
Representation of thermal building simulation in virtual reality for sustainable building
2014
The importance of energy efficiency as well as integration of advances in sustainable buildingdesign and VR technology have lead this research to focus on thermal simulation results visualized in avirtual environment (VE). The emphasis is on the representation of thermal building simulation (TBS)results and on the perception of thermal data simulated in a VE. The current application of the designprocess through energy efficiency in VR systems is limited mostly to building performance predictionsand design review, as the issue of the data formats and the workflow used for 3D modeling, thermalcalculation and VR visualization.Different applications and tools involved to represent TBS in VE are…
The Usage of Quadtree in Deep Neural Networks to Represent Data For Navigation From a Monocular Camera
2022
Depth acquisition represents a key element for navigation tasks. It is, therefore, one of the major research topics in computer vision. Many approaches have been developed to address this problem by constructing the depth from series of images. However, there is a minimal case proposing a prediction from a single image, made possible with the emergence of deep learning approaches. The latter makes it possible to consider a reduction in both hardware and computing time costs, which is beneficial for embedded systems. However, network architecture remains a heavy process requiring a lot of GPU memory. Few approaches have proposed addressing this problem by developing lightweight architectures…
Analysis and recognition of vibratory signals : contribution to the treatment and analysis of cardiac signals for telemedecine
2014
The heart is a muscle. Its mechanical operation is like a pump charged for distributing and retrieving the blood in the lungs and cardiovascular system. Its electrical operation is regulated by the sinus node, a pacemaker or electric regulator responsible for triggering the natural heart beats that punctuate the functioning of the body.Doctors monitor the electromechanical functioning of the heart by recording an electrical signal called an electrocardiogram (ECG) or an audible signal : the phonocardiogram (PCG). The analysis and processing of these two signals are essential for diagnosis, to help detect anomalies and cardiac pathologies.The objective of this thesis is to develop signal pro…
Nouvelle approche pour l'estimation du rythme respiratoire basée sur la photopléthysmographie sans contact
2021
Respiratory rhythm is important information in medical context.Its assessment allows to predict some medical complications that could lead to death.However, it is often neglected by the medical staff due to a bad comprehension of its importance, or a lack of time.Automated measurement methods allow to improve this by continuously giving respiratory rate.Most of these methods needs a contact with the patient to efficiently measure the breathing rate.Unfortunately it leads to some issues which could forbid measurement or make it unconfortable for continuous monitoring.The continuous, every-day monitoring especially needs to be as discrete as possible to be forgotten by the patient.To deal wit…
Electrocardiogram Signal Analysing
2016
In this paper, we develop a new approach based on nonlinear filtering scheme (NLFS) on cardiac signal to evaluate a robust single-lead electrocardiogram (ECG) delineation system and waves localization method based on nonlinear filtering approach. This system is built in two phases, in the first phase, we proposed a mathematical model for detecting ECG features like QRS complex peak, P and T-waves onsets and ends fromnoise free of synthetic ECG signal. Later, we develop a theoretical model to obtain real approach for detecting these features from real noisy ECG signals. Our method has been evaluated on electrocardiogram signals of QT-MIT standard database, the QRS peak achieve sensitivity (S…
Progressive transmission of secured images with authentication using decompositions into monovariate functions
2014
International audience; We propose a progressive transmission approach of an image authenticated using an overlapping subimage that can be removed to restore the original image. Our approach is different from most visible water- marking approaches that allow one to later remove the watermark, because the mark is not directly introduced in the two-dimensional image space. Instead, it is rather applied to an equivalent monovariate representation of the image. Precisely, the approach is based on our progressive transmission approach that relies on a modified Kolmogorov spline network, and therefore inherits its advantages: resilience to packet losses during transmis- sion and support of hetero…