14,406 research outputs found
CompenNet++: End-to-end Full Projector Compensation
Full projector compensation aims to modify a projector input image such that
it can compensate for both geometric and photometric disturbance of the
projection surface. Traditional methods usually solve the two parts separately,
although they are known to correlate with each other. In this paper, we propose
the first end-to-end solution, named CompenNet++, to solve the two problems
jointly. Our work non-trivially extends CompenNet, which was recently proposed
for photometric compensation with promising performance. First, we propose a
novel geometric correction subnet, which is designed with a cascaded
coarse-to-fine structure to learn the sampling grid directly from photometric
sampling images. Second, by concatenating the geometric correction subset with
CompenNet, CompenNet++ accomplishes full projector compensation and is
end-to-end trainable. Third, after training, we significantly simplify both
geometric and photometric compensation parts, and hence largely improves the
running time efficiency. Moreover, we construct the first setup-independent
full compensation benchmark to facilitate the study on this topic. In our
thorough experiments, our method shows clear advantages over previous arts with
promising compensation quality and meanwhile being practically convenient.Comment: To appear in ICCV 2019. High-res supplementary material:
https://www3.cs.stonybrook.edu/~hling/publication/CompenNet++_sup-high-res.pdf.
Code: https://github.com/BingyaoHuang/CompenNet-plusplu
Micro Fourier Transform Profilometry (FTP): 3D shape measurement at 10,000 frames per second
Recent advances in imaging sensors and digital light projection technology
have facilitated a rapid progress in 3D optical sensing, enabling 3D surfaces
of complex-shaped objects to be captured with improved resolution and accuracy.
However, due to the large number of projection patterns required for phase
recovery and disambiguation, the maximum fame rates of current 3D shape
measurement techniques are still limited to the range of hundreds of frames per
second (fps). Here, we demonstrate a new 3D dynamic imaging technique, Micro
Fourier Transform Profilometry (FTP), which can capture 3D surfaces of
transient events at up to 10,000 fps based on our newly developed high-speed
fringe projection system. Compared with existing techniques, FTP has the
prominent advantage of recovering an accurate, unambiguous, and dense 3D point
cloud with only two projected patterns. Furthermore, the phase information is
encoded within a single high-frequency fringe image, thereby allowing
motion-artifact-free reconstruction of transient events with temporal
resolution of 50 microseconds. To show FTP's broad utility, we use it to
reconstruct 3D videos of 4 transient scenes: vibrating cantilevers, rotating
fan blades, bullet fired from a toy gun, and balloon's explosion triggered by a
flying dart, which were previously difficult or even unable to be captured with
conventional approaches.Comment: This manuscript was originally submitted on 30th January 1
A comparison of results from two simulators used for studies of astronaut maneuvering units
A comparison of the results from a fixed-base, six-degree-of -freedom simulator and a moving-base, three-degree-of-freedom simulator was made for a close-in, EVA-type maneuvering task in which visual cues of a target spacecraft were used for guidance. The maneuvering unit (the foot-controlled maneuvering unit of Skylab Experiment T020) employed an on-off acceleration command control system operated entirely by the feet. Maneuvers by two test subjects were made for the fixed-base simulator in six and three degrees of freedom and for the moving-base simulator in uncontrolled and controlled, EVA-type visual cue conditions. Comparisons of pilot ratings and 13 different quantitative parameters from the two simulators are made. Different results were obtained from the two simulators, and the effects of limited degrees of freedom and uncontrolled visual cues are discussed
Overview of Advanced LIGO Adaptive Optics
This is an overview of the adaptive optics used in Advanced LIGO (aLIGO),
known as the thermal compensation system (TCS). The thermal compensation system
was designed to minimize thermally-induced spatial distortions in the
interferometer optical modes and to provide some correction for static
curvature errors in the core optics of aLIGO. The TCS is comprised of ring
heater actuators, spatially tunable CO laser projectors and Hartmann
wavefront sensors. The system meets the requirements of correcting for nominal
distortion in Advanced LIGO to a maximum residual error of 5.4nm, weighted
across the laser beam, for up to 125W of laser input power into the
interferometer
An affordable surround-screen virtual reality display
Building a projection-based virtual reality display is a time, cost, and resource intensive enterprise andmany details contribute to the final display quality. This is especially true for surround-screen displays wheremost of them are one-of-a-kind systems or custom-made installations with specialized projectors, framing, andprojection screens. In general, the costs of acquiring these types of systems have been in the hundreds and evenmillions of dollars, specifically for those supporting synchronized stereoscopic projection across multiple screens.Furthermore, the maintenance of such systems adds an additional recurrent cost, which makes them hard to affordfor a general introduction in a wider range of industry, academic, and research communities.We present a low-cost, easy to maintain surround-screen design based on off-the-shelf affordable componentsfor the projection screens, framing, and display system. The resulting system quality is comparable to significantlymore expensive commercially available solutions. Additionally, users with average knowledge can implement ourdesign and it has the added advantage that single components can be individually upgraded based on necessity aswell as available funds
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