Depth from Defocus via Active Quasi-random Point Projections

Depth sensing has many practical applications in vision-relatedtasks. While many different depth measurement techniques existand depth camera technologies are constantly being advanced, activedepth sensing still rely on specialized hardware that are highlycomplex and costly. Motivated by this, we present a novel techniquefor inferring depth measurements via depth from defocus usingactive quasi-random point projection patterns. A quasi-randompoint projection pattern is projected onto the scene of interest, andeach projection point in the image captured by a camera is analysedusing a calibration model to estimate the depth at that point.The proposed method has a relatively simple setup, consisting of acamera and a projector, and enables depth inference from a singlecapture. Furthermore, the use of a quasi-random projection patterncan allow us to leverage compressive sensing theory to producefull depth maps in future applications. Experimental resultsshow the proposed system has strong potential for enabling activedepth sensing in a simple, efficient manner

Depth from Defocus via Active Multispectral Quasi-random Point Projections using Deep Learning

A novel approach for inferring depth measurements via multispectralactive depth from defocus and deep learning has been designed,implemented, and successfully tested. The scene is activelyilluminated with a multispectral quasi-random point pattern,and a conventional RGB camera is used to acquire images of theprojected pattern. The projection points in the captured image ofthe projected pattern are analyzed using an ensemble of deep neuralnetworks to estimate the depth at each projection point. A finaldepth map is then reconstructed algorithmically based on the pointdepth estimates. Experiments using different test scenes with differentstructural characteristics show that the proposed approachcan produced improved depth maps compared to prior deep learningapproaches using monospectral projection patterns

Chemical transport across the ITCZ in the central Pacific during an El Niño-Southern Oscillation cold phase event in March-April 1999

We examine interhemispheric transport processes that occurred over the central Pacific during the PEM-Tropics B mission (PTB) in March-April 1999 by correlating the observed distribution of chemical tracers with the prevailing and anomalous windfields. The Intertropical Convergence Zone (ITCZ) had a double structure during PTB, and interhemispheric mixing occurred in the equatorial region between ITCZ branches. The anomalously strong tropical easterly surface wind had a large northerly component across the equator in the central Pacific, causing transport of aged, polluted air into the Southern Hemisphere (SH) at altitudes below 4 km. Elevated concentrations of chemical tracers from the Northern Hemisphere (NH) measured south of the equator in the central Pacific during PTB may represent an upper limit because the coincidence of seasonal and cold phase ENSO conditions are optimum for this transport. Stronger and more consistent surface convergence between the northeasterly and southeasterly trade winds in the Southern Hemisphere (SH) resulted in more total convective activity in the SH branch of the ITCZ, at about 6° S. The middle troposphere between 4-7 km was a complex shear zone between prevailing northeasterly winds at low altitudes and southwesterly winds at higher altitudes. Persistent anomalous streamline patterns and the chemical tracer distribution show that during PTB most transport in the central Pacific was from SH to NH across the equator in the upper troposphere. Seasonal differences in source strength caused larger interhemispheric gradients of chemical tracers during PTB than during the complementary PEM-Tropics A mission in September-October 1996. Copyright 2001 by the American Geophysical Union

Understanding the robustness difference between stochastic gradient descent and adaptive gradient methods

Stochastic gradient descent (SGD) and adaptive gradient methods, such as Adam and RMSProp, have been widely used in training deep neural networks. We empirically show that while the difference between the standard generalization performance of models trained using these methods is small, those trained using SGD exhibit far greater robustness under input perturbations. Notably, our investigation demonstrates the presence of irrelevant frequencies in natural datasets, where alterations do not affect models' generalization performance. However, models trained with adaptive methods show sensitivity to these changes, suggesting that their use of irrelevant frequencies can lead to solutions sensitive to perturbations. To better understand this difference, we study the learning dynamics of gradient descent (GD) and sign gradient descent (signGD) on a synthetic dataset that mirrors natural signals. With a three-dimensional input space, the models optimized with GD and signGD have standard risks close to zero but vary in their adversarial risks. Our result shows that linear models' robustness to $\ell_2$-norm bounded changes is inversely proportional to the model parameters' weight norm: a smaller weight norm implies better robustness. In the context of deep learning, our experiments show that SGD-trained neural networks show smaller Lipschitz constants, explaining the better robustness to input perturbations than those trained with adaptive gradient methods

Homelessness & Adverse Childhood Experiences: The Health and Behavioral Health Consequences of Childhood Trauma

This fact sheet was developed by the National Health Care for the Homeless Council and the National Network to End Family Homelessness, an initiative of The Bassuk Center on Homelessness and Vulnerable Children and Youth. The purpose is to ensure clinicians working with people experiencing homelessness understand the role of Adverse Childhood Experiences (ACEs) in health outcomes as well as the options for responding

Chemical characteristics of air from different source regions during the second Pacific Exploratory Mission in the Tropics (PEM-Tropics B)

Ten-day backward trajectories are used to determine the origins of air parcels arriving at locations of airborne DC-8 chemical measurements during NASA's second Pacific Exploratory Mission in the Tropics B that was conducted during February-April 1999. Chemical data at sites where the trajectories had a common geographical origin and transport history are grouped together, and statistical measures of chemical characteristics are computed. Temporal changes in potential temperature are used to determine whether trajectories experienced a significant convective influence during the 10-day period. Trajectories describing the aged marine Southern Hemispheric category remain over the South Pacific Ocean during the 10-day period, and their corresponding chemical signature indicates very clean air. The category aged marine air in the Northern Hemisphere is found to be somewhat dirtier. Subdividing its trajectories based on the direction from which the air had traveled is found to be important in explaining the various chemical signatures. Similarly, long-range northern hemispheric trajectories passing over Asia are subdivided depending on whether they had followed a mostly zonal path, had originated near the Indian Ocean, or had originated near Central or South America and subsequently experienced a stratospheric influence. Results show that the chemical signatures of these subcategories are different from each other. The chemical signature of the southern hemispheric long-range transport category apparently exhibits the effects of pollution from Australia, southern Africa, and South America. Parcels originating over Central and northern South America are found to contain the strongest pollution signature of all categories, due to biomass burning and other sources. The convective category exhibits enhanced values of nitrogen species, probably due to emissions from lightning associated with the convection. Values of various species, including peroxides and acids, confirm that parcels were influenced by the removal of soluble gas and particle species due to precipitation. Finally, current results are compared with those from the first PEM-Tropics mission that was conducted in the same region during the southern hemispheric dry season (August-October 1996) when extensive biomass burning occurred. Results show that air samples during PEM-Tropics B are considerably cleaner than those of its dry season counterpart. Copyright 2001 by the American Geophysical Union

Motion Detection in High Resolution Enhancement

Shifted Superposition (SSPOS) is a resolution enhancement methodwhere apparent high-resolution content is displayed using a lowresolutionprojection system with an opto-mechanical shifter. WhileSSPOS-enhanced projectors have been showing promising resultsin still images, they still suffer from motion artifacts in video contents.Motivated by this, we present a novel approach to apparentprojector resolution enhancement for videos via motion-basedblurring module. We propose the use of a motion detection moduleand a blurring module to compensate for both SSPOS-resulted andnatural motion artifacts in the video content. To accomplish this,we combine both local and global motion estimation algorithms togenerate accurate dense flow fields. The detected motion regionsare enhanced using directional Gaussian filters. Preliminary resultsshow that the proposed method can produce accurate densemotion vectors and significantly reduce the artifacts in videos

Influence of regional-scale anthropogenic emissions on CO2 distributions over the western North Pacific

We report here airborne measurements of atmospheric CO2 over the western North Pacific during the March-April 2001 Transport and Chemical Evolution over the Pacific (TRACE-P) mission. The CO2 spatial distributions were notably influenced by cyclogenesis-triggered transport of regionally polluted continental air masses. Examination of the CO2 to C2H2/CO ratio indicated rapid outflow of combustion-related emissions in the free troposphere below 8 km. Although the highest CO2 mixing ratios were measured within the Pacific Rim region, enhancements were also observed further east over the open ocean at locations far removed from surface sources. Near the Asian continent, discrete plumes encountered within the planetary boundary layer contained up to 393 ppmv of CO2. Coincident enhancements in the mixing ratios of C2Cl4, C2H2, and C2H4 measured concurrently revealed combustion and industrial sources. To elucidate the source distributions of CO2, an emissions database for Asia was examined in conjunction with the chemistry and 5-day backward trajectories that revealed the WNW/W sector of northeast Asia was a major contributor to these pollution events. Comparisons of NOAA/CMDL and JMA surface data with measurements obtained aloft showed a strong latitudinal gradient that peaked between 35° and 40°N. We estimated a net CO2 flux from the Asian continent of approximately 13.93 Tg C day-1 for late winter/early spring with the majority of the export (79%) occurring in the lower free troposphere (2-8 km). The apportionment of the flux between anthropogenic and biospheric sources was estimated at 6.37 Tg C day-1 and 7.56 Tg C day-1, respectively