240 research outputs found
Photon counting compressive depth mapping
We demonstrate a compressed sensing, photon counting lidar system based on
the single-pixel camera. Our technique recovers both depth and intensity maps
from a single under-sampled set of incoherent, linear projections of a scene of
interest at ultra-low light levels around 0.5 picowatts. Only two-dimensional
reconstructions are required to image a three-dimensional scene. We demonstrate
intensity imaging and depth mapping at 256 x 256 pixel transverse resolution
with acquisition times as short as 3 seconds. We also show novelty filtering,
reconstructing only the difference between two instances of a scene. Finally,
we acquire 32 x 32 pixel real-time video for three-dimensional object tracking
at 14 frames-per-second.Comment: 16 pages, 8 figure
Photon Counting Compressive Depth Mapping
We demonstrate a compressed sensing, photon counting lidar system based on the single-pixel camera. Our technique recovers both depth and intensity maps from a single under-sampled set of incoherent, linear projections of a scene of interest at ultra-low light levels around 0.5 picowatts. Only two-dimensional reconstructions are required to image a three-dimensional scene. We demonstrate intensity imaging and depth mapping at 256 Ă— 256 pixel transverse resolution with acquisition times as short as 3 seconds. We also show novelty filtering, reconstructing only the difference between two instances of a scene. Finally, we acquire 32 Ă— 32 pixel real-time video for three-dimensional object tracking at 14 frames-per-second
Electronic Chart of the Future: The Hampton Roads Project
ECDIS is evolving from a two-dimensional static display of chart-related data to a decision support system capable of providing real-time or forecast information. While there may not be consensus on how this will occur, it is clear that to do this, ENC data and the shipboard display environment must incorporate both depth and time in an intuitively understandable way. Currently, we have the ability to conduct high-density hydrographic surveys capable of producing ENCs with decimeter contour intervals or depth areas. Yet, our existing systems and specifications do not provide for a full utilization of this capability. Ideally, a mariner should be able to benefit from detailed hydrographic data, coupled with both forecast and real-time water levels, and presented in a variety of perspectives. With this information mariners will be able to plan and carry out transits with the benefit of precisely determined and easily perceived underkeel, overhead, and lateral clearances. This paper describes a Hampton Roads Demonstration Project to investigate the challenges and opportunities of developing the “Electronic Chart of the Future.” In particular, a three-phase demonstration project is being planned: 1. Compile test datasets from existing and new hydrographic surveys using advanced data processing and compilation procedures developed at the University of New Hampshire’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center (CCOM/JHC); 2. Investigate innovative approaches being developed at the CCOM/JHC to produce an interactive time- and tide-aware navigation display, and to evaluate such a display on commercial and/or government vessels; 3. Integrate real-time/forecast water depth information and port information services transmitted via an AIS communications broadcast
Genetic Evaluation of Cardiomyopathy - a Heart Failure Society of America Practice Guideline
This guideline describes the approach and expertise needed for the genetic evaluation of cardiomyopathy. First published in 2009 by the Heart Failure Society of America (HFSA), this guidance has now been updated in collaboration with the American College of Medical Genetics and Genomics (ACMG). The writing group, composed of cardiologists and genetics professionals with expertise in adult and pediatric cardiomyopathy, reflects the emergence and increased clinical activity devoted to cardiovascular genetic medicine. The genetic evaluation of cardiomyopathy is a rapidly emerging key clinical priority, as high throughput sequencing is now feasible for clinical testing, and conventional interventions can improve survival, reduce morbidity, and enhance quality of life. Moreover, specific interventions may be guided by genetic analysis. A systematic approach is recommended: always a comprehensive family history; an expert phenotypic evaluation of the proband and at-risk family members to confirm a diagnosis and guide genetic test selection and interpretation; referral to expert centers as needed; genetic testing, with pre- and post-test genetic counseling; and specific guidance as indicated for drug and device therapies. The evaluation of infants and children demands special expertise. The approach to manage secondary and incidental sequence findings as recommended by the ACMG is provided
Enhanced ultrafast X-ray diffraction by transient resonances
Diffraction-before-destruction imaging with single ultrashort X-ray pulses
has the potential to visualise non-equilibrium processes, such as chemical
reactions, at the nanoscale with sub-femtosecond resolution in the native
environment without the need of crystallization. Here, a nanospecimen partially
diffracts a single X-ray flash before sample damage occurs. The structural
information of the sample can be reconstructed from the coherent X-ray
interference image. State-of-art spatial resolution of such snapshots from
individual heavy element nanoparticles is limited to a few nanometers. Further
improvement of spatial resolution requires higher image brightness which is
ultimately limited by bleaching effects of the sample. We compared snapshots
from individual 100 nm Xe nanoparticles as a function of the X-ray pulse
duration and incoming X-ray intensity in the vicinity of the Xe M-shell
resonance. Surprisingly, images recorded with few femtosecond and
sub-femtosecond pulses are up to 10 times brighter than the static linear model
predicts. Our Monte-Carlo simulation and statistical analysis of the entire
data set confirms these findings and attributes the effect to transient
resonances. Our simulation suggests that ultrafast form factor changes during
the exposure can increase the brightness of X-ray images by several orders of
magnitude. Our study guides the way towards imaging with unprecedented
combination of spatial and temporal resolution at the nanoscale
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