Albertsenkearney3074

We proposed a method for extracting the optical flow suitable for visualization, pseudo-flow (P-flow), from a natural movie [Exp. Brain Res.237, 3321 (2019)EXBRAP0014-481910.1007/s00221-019-05674-0]. The P-flow algorithm comprises two stages (1) extraction of a local motion vector field from two successive frames and (2) tracking of vectors between two successive frame pairs. In this study, we show that while P-flow takes a feature (vector) tracking approach, it is also classified as a gradient-based approach that satisfies the brightness constancy constraint. We also incorporate interpolation and a corner detector to address the shortcomings associated with the two approaches.Monitoring strain is important in precision engineering applications that require maintaining the precise alignments of structures over time, such as those found in machine tools and metrology frames. We present a fiber-optic strain measurement technique based upon broadband interferometry that is variously configurable in terms of gauge length and sensitivity. This is achieved by the use of an unbalanced interrogation interferometer configuration that alleviates the cavity length limit imposed by the temporal coherence of the system. We also demonstrate that dispersion in fiber sensors based on intrinsic Fabry-Perot interferometers must be considered to optimize performance. The possibility of multisensor interrogation using the same optical system is also reported.We use Mellin-transform techniques to derive generalized expressions for the piston-removed and piston-and-tilt-removed anisoplanatic error in non-Kolmogorov turbulence with a finite outer scale. We use these expressions to investigate the behavior of the anisoplanatic error when imaging over long horizontal paths where the angular extent of the scene is often many times the isoplanatic angle. By evaluating these expressions, we first find that in many cases, the anisoplanatic error saturates to a value less than 1rad2. Next, as power law increases, the contributions due to piston and tilt dominate the anisoplanatic error expression. Last, the size of the outer scale contributes primarily to the piston and tilt terms. Together, these behaviors imply that when piston and tilt are removed, anisoplanatism is reduced by as much as 60%.A visual experiment using a beam-splitter-based optical see-through augmented reality (OST-AR) setup tested the effect of the size and alignment of AR overlays with a brightness-matching task using physical cubes. Results indicate that more luminance is required when AR overlays are oversized with respect to the cubes, showing that observers discount the AR overlay to a greater extent when it is more obviously a transparent layer. This is not explained by conventional color appearance modeling but supports an AR-specific model based on foreground-background discounting. The findings and model will help determine parameters for creating convincing AR manipulation of real-world objects.We present a novel acquisition scheme based on a dual-disperser architecture, which can reconstruct a hyperspectral datacube using many times fewer acquisitions than spectral bands. The reconstruction algorithm follows a quadratic regularization approach, based on the assumption that adjacent pixels in the scene share similar spectra, and, if they do not, this corresponds to an edge that is detectable on the panchromatic image. A digital micro-mirror device applies reconfigurable spectral-spatial filtering to the scene for each acquisition, and the filtering code is optimized considering the physical properties of the system. The algorithm is tested on simple multi-spectral scenes with 110 wavelength bands and is able to accurately reconstruct the hyperspectral datacube using only 10 acquisitions.The traditional Born series (TBS) and convergent Born series (CBS) methods to numerically solve the time-independent inhomogeneous photoacoustic (PA) wave equation are discussed. The performance of these algorithms is examined for a circular PA source (a disk of radius, a=5µm) in two dimensions. The speed of sound within the source region was gradually decreased from vs=1950 to 1200 m/s, but the same quantity for the ambient medium was fixed to vf=1500m/s. The PA fields were calculated over a large frequency band from f=7.3 to 2000 MHz. Accordingly, the wave number (kf=2πf/vf) varied from kf=0.03 to 8.38µm-1. The TBS method does not offer converging solutions when kfa≥25 for vs=1950m/s and kfa≥9 for vs=1200m/s. These have been observed in both the near and far fields. Selleck Peficitinib However, the solutions for the CBS technique converge in all cases. Both methods facilitate accurate solutions if the computational domain contains a collection of monodisperse/polydisperse disks considered in this study. Our numerical results suggest that the CBS protocol can provide accurate solutions under various test conditions.This publisher's note corrects the Fig. 6 caption in J. Opt. Soc. Am. A37, C1 (2020)JOAOD60740-323210.1364/JOSAA.385913.This publisher's note corrects the contents of references in J. Opt. Soc. Am. A37, 1043 (2020)JOAOD60740-323210.1364/JOSAA.393027.A frequency dependent differential photoacoustic cross-section (DPACS) over a large frequency band (100-1000 MHz) was computed, and subsequently, morphological parameters of a photoacoustic (PA) source were quantified. The Green's function approach was utilized for calculating the DPACS for spheroidal droplets with varying aspect ratios, Chebyshev particles with different waviness and deformation parameters, and normal red blood cells and cells affected by hereditary disorders (e.g., spherocytosis, elliptocytosis, and stomatocytosis). The theoretical framework considers that PA waves propagate through an acoustically dispersive and absorbing medium and are detected by a planar detector of finite size. The frequency dependent DPACS profile was fitted with tri-axial ellipsoid, finite cylinder, and toroid form factor models to obtain size and shape information of the PA source. The tri-axial ellipsoid form factor model was found to provide better estimates of the shape parameters compared to other models for a variety of sources.