5,803 research outputs found
Efficient Human Pose Estimation with Image-dependent Interactions
Human pose estimation from 2D images is one of the most challenging
and computationally-demanding problems in computer vision. Standard
models such as Pictorial Structures consider interactions between
kinematically connected joints or limbs, leading to inference cost
that is quadratic in the number of pixels. As a result, researchers
and practitioners have restricted themselves to simple models which
only measure the quality of limb-pair possibilities by their 2D
geometric plausibility.
In this talk, we propose novel methods which allow for efficient
inference in richer models with data-dependent interactions. First, we
introduce structured prediction cascades, a structured analog of
binary cascaded classifiers, which learn to focus computational effort
where it is needed, filtering out many states cheaply while ensuring
the correct output is unfiltered. Second, we propose a way to
decompose models of human pose with cyclic dependencies into a
collection of tree models, and provide novel methods to impose model
agreement. Finally, we develop a local linear approach that learns
bases centered around modes in the training data, giving us
image-dependent local models which are fast and accurate.
These techniques allow for sparse and efficient inference on the order
of minutes or seconds per image. As a result, we can afford to model
pairwise interaction potentials much more richly with data-dependent
features such as contour continuity, segmentation alignment, color
consistency, optical flow and multiple modes. We show empirically that
these richer models are worthwhile, obtaining significantly more
accurate pose estimation on popular datasets
Projected Augmented Reality to Drive Osteotomy Surgery: Implementation and Comparison With Video See-Through Technology
In recent years, the spreading of visual augmented reality as an effective tool in image-guided surgery, has stimulated the research community to investigate the use of commercial augmented reality headsets a broad range of potential applications. This aroused enthusiasm among clinicians for the potential of augmented reality, but also revealed some technological and human-factor limitations that still hinder its routine adoption in the operating room. In this work, we propose an alternative to head-mounted displays, based on projected augmented reality. Projected augmented reality completely preserves the surgeon’s natural view of the operating field, because it requires no perspective conversion and/or optical mediation. We selected a cranio-maxillofacial surgery application as a benchmark to test the proposed system and compare its accuracy with the one obtained with a video see-through system. The augmented reality overlay accuracy was evaluated by measuring the distance between a virtual osteotomy line and its real counterpart. The experimental tests showed that the accuracy of the two augmented reality modes is similar, with a median error discrepancy of about 0.3 mm for the projected augmented reality mode. Results suggest that projected augmented reality can be a valuable alternative to standard see-through head-mounted displays to support in-situ visualization of medical imaging data as surgical guidance
Robust Head Mounted Wearable Eye Tracking System for Dynamical Calibration
In this work, a new head mounted eye tracking system is presented. Based on computer vision techniques, the system integrates eye images and head movement, in real time, performing a robust gaze point tracking. Nystagmus movements due to vestibulo-ocular reflex are monitored and integrated. The system proposed here is a strongly improved version of a previous platform called HATCAM, which was robust against changes of illumination conditions. The new version, called HAT-Move, is equipped with accurate inertial motion unit to detect the head movement enabling eye gaze even in dynamical conditions. HAT-Move performance is investigated in a group of healthy subjects in both static and dynamic conditions, i.e. when head is kept still or free to move. Evaluation was performed in terms of amplitude of the angular error between the real coordinates of the fixed points and those computed by the system in two experimental setups, specifically, in laboratory settings and in a 3D virtual reality (VR) scenario. The achieved results showed that HAT-Move is able to achieve eye gaze angular error of about 1 degree along both horizontal and vertical direction
Aeronautical Engineering: A special bibliography with indexes, supplement 62
This bibliography lists 306 reports, articles, and other documents introduced into the NASA scientific and technical information system in September 1975
Ciclogénesis explosivas en el sector Euro-Atlántico: estudio de su dinámica a gran escala y variabilidad
Tesis inĂ©dita de la Universidad Complutense de Madrid, Facultad de Ciencias FĂsicas, Departamento de FĂsica de la Tierra, AstronomĂa y AstrofĂsica I (GeofĂsica y MeteorologĂa) (AstronomĂa y Geodesia), leĂda el 27-11-2015.Depto. de FĂsica de la Tierra y AstrofĂsicaFac. de Ciencias FĂsicasTRUEunpu
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