1,256 research outputs found

    Reconstructing the 3-D Trajectories of CMEs in the Inner Heliosphere

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    A method for the full three-dimensional (3-D) reconstruction of the trajectories of coronal mass ejections (CMEs) using Solar TErrestrial RElations Observatory (STEREO) data is presented. Four CMEs that were simultaneously observed by the inner and outer coronagraphs (COR1 and 2) of the Ahead and Behind STEREO satellites were analysed. These observations were used to derive CME trajectories in 3-D out to ~15Rsun. The reconstructions using COR1/2 data support a radial propagation model. Assuming pseudo-radial propagation at large distances from the Sun (15-240Rsun), the CME positions were extrapolated into the Heliospheric Imager (HI) field-of-view. We estimated the CME velocities in the different fields-of-view. It was found that CMEs slower than the solar wind were accelerated, while CMEs faster than the solar wind were decelerated, with both tending to the solar wind velocity.Comment: 17 pages, 10 figures, 1 appendi

    The Solar Orbiter mission and its prospects for helioseismology

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    Solar Orbiter is intended to become ESA's next solar mission in heritage of the successful SOHO project. The scientific objectives of the mission, its design, and its scientific payload are reviewed. Specific emphasis is given to the perspectives of Solar Orbiter with respect to helioseismology.Comment: 6 pages, 4 figure

    Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

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    One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

    The SMART-I²: A new approach for the design of immersive audio-visual environments

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    International audienceThe SMART-I² aims at creating a precise and coherent virtual environment by providing users with both audio and visual accurate localization cues. Wave field synthesis, for audio rendering, and tracked passive stereoscopy, for visual rendering, individually permit high quality spatial immersion within an extended space. The proposed system combines these two rendering approaches through the use of large multi-actuator panels used as both loudspeaker arrays and as projection screens, providing a more perceptually consistent rendering

    Analysis of RGB-D camera technologies for supporting different facial usage scenarios

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    Recently a wide variety of applications has been developed integrating 3D functionalities. Advantages given by the possibility of relying on depth information allows the developers to design new algorithms and to improve the existing ones. In particular, for what concerns face morphology, 3D has led to the possibility to obtain face depth maps highly close to reality and consequently an improvement of the starting point for further analysis such as Face Detection, Face Authentication, Face Identification and Face Expression Recognition. The development of the aforementioned applications would have been impossible without the progress of sensor technologies for obtaining 3D information. Several solutions have been adopted over time. In this paper, emphasis is put on passive stereoscopy, structured light, time-of-flight (ToF) and active stereoscopy, namely the most used technologies for the cameras design and fulfilment according to the literature. The aim of this article is to investigate facial applications and to examine 3D camera technologies to suggest some guidelines for addressing the correct choice of a 3D sensor according to the application that has to be developed

    Analysis of RGB-D camera technologies for supporting different facial usage scenarios

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    AbstractRecently a wide variety of applications has been developed integrating 3D functionalities. Advantages given by the possibility of relying on depth information allows the developers to design new algorithms and to improve the existing ones. In particular, for what concerns face morphology, 3D has led to the possibility to obtain face depth maps highly close to reality and consequently an improvement of the starting point for further analysis such as Face Detection, Face Authentication, Face Identification and Face Expression Recognition. The development of the aforementioned applications would have been impossible without the progress of sensor technologies for obtaining 3D information. Several solutions have been adopted over time. In this paper, emphasis is put on passive stereoscopy, structured light, time-of-flight (ToF) and active stereoscopy, namely the most used technologies for the cameras design and fulfilment according to the literature. The aim of this article is to investigate facial applications and to examine 3D camera technologies to suggest some guidelines for addressing the correct choice of a 3D sensor according to the application that has to be developed

    Methods for producing stereoscopic imagery

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    This paper describes methodologies for creating computer graphics stereoscopic imagery. This thesis details the positive and negative aspects for producing and post-producing stereoscopic imagery using different stereoscopic tools provided by Autodesk Maya and The Foundry Nuke. Also, in order to increase efficiency and decrease production time, Python tools were developed both for Maya and Nuke. Finally, the methodology proposed in this paper is fully functional and can be adopted by any production
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