Search results for " image processing."

Étude de la Dynamique des Ondes Spirales à l'Échelle Cellulaire par Modèles Expérimental et Numérique

2012

Among the death due to the cardiac problems, the arrhythmias play a major role, particularly the atrial disorders. This alarming situation attracts an intense research, but it is still limited by the availability of experimental models to reproduce the triggering mechanisms of arrhythmias at the cellular level and extensions of these anomalies. Whether they occur on a healthy or pathological heart, or they are benign or potentially dangerous (risk of sudden death), the arrhythmias constitute an important chapter of the cardiology. This thesis is interested in the studying and modeling of the arrhythmias at a cellular scale. Thus the problems of this thesis can be summarized briefly by the f…

Noise estimation from digital step-model signal

2013

International audience; This paper addresses the noise estimation in the digital domain and proposes a noise estimator based on the step signal model. It is efficient for any distribution of noise because it does not rely only on the smallest amplitudes in the signal or image. The proposed approach uses polarized/directional derivatives and a nonlinear combination of these derivatives to estimate the noise distribution (e.g., Gaussian, Poisson, speckle, etc.). The moments of this measured distribution can be computed and are also calculated theoretically on the basis of noise distribution models. The 1D performances are detailed, and as our work is mostly dedicated to image processing, a 2D…

Entire Reflective Object Surface Structure Understanding

2015

International audience

SiPM cryogenic operation down to 77 K

2013

International audience; Silicon PhotoMultiplier (SiPM) is composed of extremely sensitive photosensors based on the Geiger Mode Avalanche PhotoDiode (GM-APD), which operate as a digital pixel sensitive to single photons. SiPMs are being considered for applications in low temperature environments, such as noble-liquid detectors for dark matter searches or neutrino physics and GM-APD is promising technology for space Compton telescopes. While it is well known that the dark count rate, one of the main limitations of SiPM, is reduced at low temperature, a detailed study of the behavior of the device in cryogenic environment is necessary to assess its performances. In this paper, we present meas…

Procédé et dispositif de détermination de paramètres représentatifs d'une activité cardiovasculaire

2015

A century of warfare shoots holes in anti-Caulerpa campaign

2007

doi:10.1038 /npre.2007.1240.1; International audience; no abstract

Perceptual Spatial Uniformity Assessment of Projection Displays with a Calibrated Camera

2014

International audience; Spatial uniformity is one of the most important image quality attributes in visual experience of displays. In conventional researches, spatial uniformity was mostly measured with a radiometer and its quality was assessed with non-reference image quality metrics. Cameras are cheaper than radiometers and they can provide accurate relative measurements if they are carefully calibrated. In this paper, we propose and implement a work-flow to use a calibrated camera as a relative acquisition device of intensity to measure the spatial uniformity of projection displays. The camera intensity transfer functions for every projected pixels are recovered, so we can produce multip…

High Dynamic Range Real-time Vision System for Robotic Applications

2012

International audience; Robotics applications often requires vision systems capable of capturing a large amount of information related to a scene. With many camera sensors, the perception of information is limited in areas with strong contrasts. The High Dynamic Range (HDR) vision system can deal with these limitations. This paper describes the HDR-ARtiSt hardware platform (High Dynamic Range Advanced Real-time imaging System), a FPGA-based architecture that can produce a real- time high dynamic range video from successive image acquisition.

Automatic spatial and temporal organization of long range video sequences from low level motion features

2014

International audience; In this paper, we address the analysis of activities from long range video sequences. We present a method to automatically extract spatial and temporal structure from a video sequence from low level motion features. The scene layout is first extracted, with a set of regions that have homogeneous activities called Motion Patterns. These regions are then analyzed and the recurrent temporal motifs are extracted for each Motion Patterns. Preliminary results show that our method can accurately extract important temporal motifs from video surveillance sequences.

Spatial resolution improvement of MeRIS Images by Fusion with Thematic Mapper Images

2001

International audience; no abstract