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Orsay, France

Kulcsar C.,French National Center for Scientific Research | Fezzani R.,French National Center for Scientific Research | Fezzani R.,ONERA | Le Besnerais G.,ONERA | And 2 more authors.
2014 International Workshop on Computational Intelligence for Multimedia Understanding, IWCIM 2014 | Year: 2014

Recent retinal imaging systems, including those featuring adaptative optics (AO) correction, produce sequences of images having a very high spatial resolution, but possibly affected by a low Signal-to-Noise Ratio (SNR). A simple, fast and efficient way to improve SNR in many cases is to average images. However, image quality appears to be highly variable from one frame to another, and sequences feature large inter-frame global motions due to eye movements. We consider in this paper both global and local motion estimation to deliver enhanced images or to detect vessel activity. We tackle the problem of retinal vessels local motions due to bloodstream. If not accounted for, these motions lead to some blurring of the enhanced image, which in turn degrades image analysis, for instance the estimation of the thickness of the vessels wall or the wall-to-lumen ratio. Interframe local motions need thus to be estimated. We propose to compensate for local motions using a fast optical flow estimation called FOLKI developed at ONERA/DTIM, which combines very fast computational times with a good accuracy. The method is then applied to detect vessel activity. Improvements are demonstrated both in terms of final image quality and of local activity detection, on sequences recorded on Imagine Eyes' rtx1 system. © 2014 IEEE. Source

Imagine Eyes | Date: 2012-01-27

The invention relates to a high-resolution retinal imaging method and device notably comprising an emission source (LSr) for emitting a light beam for the illumination of the retina of an eye (

Imagine Eyes | Date: 2012-02-21

The invention relates, according to one aspect, to a retinal imaging device including at least one source (LS

Kulcsar C.,University Paris - Sud | Besnerais G.L.,ONERA | Odlund E.,Imagine Eyes | Levecq X.,Imagine Eyes
Optics InfoBase Conference Papers | Year: 2013

Retinal images sequences provided by adaptive optics instruments have to be processed before clinical exploitation. We present a robust procedure that accounts for non-translational motions and variable image quality to deliver improved reconstructed images. © OSA 2013. Source

Salas M.,Medical University of Vienna | Drexler W.,Medical University of Vienna | Levecq X.,Imagine Eyes | Lamory B.,Imagine Eyes | And 5 more authors.
Biomedical Optics Express | Year: 2016

We present a new compact multi-modal imaging prototype that combines an adaptive optics (AO) fundus camera with AO-optical coherence tomography (OCT) in a single instrument. The prototype allows acquiring AO fundus images with a field of view of 4°x4° and with a frame rate of 10fps. The exposure time of a single image is 10 ms. The short exposure time results in nearly motion artifact-free high resolution images of the retina. The AO-OCT mode allows acquiring volumetric data of the retina at 200kHz A-scan rate with a transverse resolution of ~4 μm and an axial resolution of ~5 μm. OCT imaging is acquired within a field of view of 2°x2° located at the central part of the AO fundus image. Recording of OCT volume data takes 0.8 seconds. The performance of the new system is tested in healthy volunteers and patients with retinal diseases. © 2016 Optical Society of America. Source

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