A statistical approach for shadow detection using spatio-temporal contexts

Background subtraction is an important step used to segment moving regions in surveillance videos. However, cast shadows are often falsely labeled as foreground objects, which may severely degrade the accuracy of object localization and detection. Effective shadow detection is necessary for accurate foreground segmentation, especially for outdoor scenes. Based on the characteristics of shadows, such as luminance reduction, chromaticity consistency and texture consistency, we introduce a nonparametric framework for modeling surface behavior under cast shadows. To each pixel, we assign a potential shadow value with a confidence weight, indicating the probability that the pixel location is an actual shadow point. Given an observed RGB value for a pixel in a new frame, we use its recent spatio-temporal context to compute an expected shadow RGB value. The similarity between the observed and the expected shadow RGB values determines whether a pixel position is a true shadow. Experimental results show the performance of the proposed method on a suite of standard indoor and outdoor video sequences

Assessment of different methods for shadow detection in high-resolution optical imagery and evaluation of shadow impact on calculation of NDVI, and evapotranspiration

Significant efforts have been made recently in the application of high-resolution remote sensing imagery (i.e., sub-meter) captured by unmanned aerial vehicles (UAVs) for precision agricultural applications for high-value crops such as wine grapes. However, at such high resolution, shadows will appear in the optical imagery effectively reducing the reflectance and emission signal received by imaging sensors. To date, research that evaluates procedures to identify the occurrence of shadows in imagery produced by UAVs is limited. In this study, the performance of four different shadow detection methods used in satellite imagery was evaluated for high-resolution UAV imagery collected over a California vineyard during the Grape Remote sensing Atmospheric Profile and Evapotranspiration eXperiment (GRAPEX) field campaigns. The performance of the shadow detection methods was compared and impacts of shadowed areas on the normalized difference vegetation index (NDVI) and estimated evapotranspiration (ET) using the Two-Source Energy Balance (TSEB) model are presented. The results indicated that two of the shadow detection methods, the supervised classification and index-based methods, had better performance than two other methods. Furthermore, assessment of shadowed pixels in the vine canopy led to significant differences in the calculated NDVI and ET in areas affected by shadows in the high-resolution imagery. Shadows are shown to have the greatest impact on modeled soil heat flux, while net radiation and sensible heat flux are less affected. Shadows also have an impact on the modeled Bowen ratio (ratio of sensible to latent heat) which can be used as an indicator of vine stress level.info:eu-repo/semantics/acceptedVersio

Global Warming Scenarios for Ireland and their Implications for Environmental Management.

Regional climate forecasts cannot yet be derived with confidence from general circulation models of the atmosphere, particularly in terms of projecting precipitation changes at middle latitude locations such as Ireland. This paper employs several large datasets relating to Irish precipitation and synoptic circulation types to examine past and present precipitation-circulation relationships. These relationships are then used to make preliminary inferences concerning likely changes in seasonal parameters in a greenhouse-warmed Irish climate. It is concluded that increases of 5-15% in winter precipitation will be accompanied by significant reductions in summer values, especially in eastern Ireland. These projections, allied to the global predictions concerning sea level rise are then used in an examination of some implications, particularly in civil engineering aspects of environmental management

Global Warming Scenarios for Ireland and their Implications for Environmental Management.

Regional climate forecasts cannot yet be derived with confidence from general circulation models of the atmosphere, particularly in terms of projecting precipitation changes at middle latitude locations such as Ireland. This paper employs several large datasets relating to Irish precipitation and synoptic circulation types to examine past and present precipitation-circulation relationships. These relationships are then used to make preliminary inferences concerning likely changes in seasonal parameters in a greenhouse-warmed Irish climate. It is concluded that increases of 5-15% in winter precipitation will be accompanied by significant reductions in summer values, especially in eastern Ireland. These projections, allied to the global predictions concerning sea level rise are then used in an examination of some implications, particularly in civil engineering aspects of environmental management

How restricting carbon dioxide and methane emissions would affect the Indian economy

India and China contain about 40 percent of the earth's people. They are at an early stage of economic development, and their increasingly massive energy requirements will depend heavily on coal, a potent source of carbon dioxide, a powerful and long-lasting greenhouse gas. India also has important sources and uses of hydroelectric and nuclear power, petroleum, and natural gas. Agriculture still produces about 30 percent of its gross domestic product, and about 72 percent of the population lives in rural areas - with their large animal populations and substantial forest acreage. India has vast cities and an industrial sector that is large in absolute terms, although it represents only 30 percent of the economy. The model developed to analyze the economic effects of constraints on greenhouse gas emissions is a multisectoral, intertemporal linear programming model, driven by the optimization of the welfare of a representative consumer. A comprehensive model was built not to project the future at a single stroke but to begin to answer questions of a"What if?"form. The results strongly suggest that the economic effects on India of such constraints would be profound. The implications of different forms of emissions restrictions - annual, cumulative, and radiative forcing - deserve more attention. Cumulative restrictions - or better still, restrictions on radiative forcing - are closely related to public policy on greenhouse effects. Such restrictions also provide significant additional degrees of freedom for the economic adjustments required. They do this, in part, by allowing the postponement of emissions restrictions, which is not permitted by annual constraints. Of course, the question arises whether a country, having benefited from postponing a required reduction in emissions, would then be willing to face the consequences in economic losses. Might there be a genuine preference - albeit an irrational one - for taking the losses annually? Would compliance with international agreements for emissions restrictions be more likely if they required annual, rather than cumulative, reductions? Monitoring requirements would be the same in either case; if effective monitoring were carried out, it would detect departures from cumulative or radiative forcing constraints just as easily as departures from annualconstraints.Environmental Economics&Policies,Carbon Policy and Trading,Montreal Protocol,Transport and Environment,Energy and Environment

A lunar base reference mission for the phased implementation of bioregenerative life support system components

Previous design efforts of a cost effective and reliable regenerative life support system (RLSS) provided the foundation for the characterization of organisms or 'biological processors' in engineering terms and a methodology was developed for their integration into an engineered ecological LSS in order to minimize the mass flow imbalances between consumers and producers. These techniques for the design and the evaluation of bioregenerative LSS have now been integrated into a lunar base reference mission, emphasizing the phased implementation of components of such a BLSS. In parallel, a designers handbook was compiled from knowledge and experience gained during past design projects to aid in the design and planning of future space missions requiring advanced RLSS technologies. The lunar base reference mission addresses in particular the phased implementation and integration of BLS parts and includes the resulting infrastructure burdens and needs such as mass, power, volume, and structural requirements of the LSS. Also, operational aspects such as manpower requirements and the possible need and application of 'robotics' were addressed

Deep Impact Mission to Tempel 1 Favours New Explosive Cosmogony of Comets

The assumption that short-period (SP) comets are fragments of massive icy envelopes of Ganymede-like bodies saturated by products of ice electrolysis that underwent global explosions provides a plausible explanation of all known manifestations of comets, including the jet character of outflows, the presence of ions in the vicinity of the nucleus, the bursts and splitting of cometary nuclei, etc., with solar radiation initiating burning of the products of electrolysis in the nucleus. As shown persuasively by numerical simulation carried out in hydrodynamic approximation, the shock wave initiated by the Deep Impact (DI) impactor in the cometary ice saturated originally by the electrolysis products 2H2 + O2 is capable of activating under certain conditions exothermal reactions (of the type O2 + H2 + organics = H2O + CO + HCN + other products of incomplete burning of organics including its light and heavy pyrolyzed compounds, soot, etc.), which will slow down shock wave damping (forced detonation) and increase many times the energy release. As a result, the measured energetics of ejections and outflows from the crater have to exceed the DI energetics. Analysis of different clusters of the DI experiment data confirms these conclusions and expectations and thus it favours the planetary origin of comets.Comment: 21 pages incluging 3 figure

Time Enough - Consequences of Human Microchip Implantation

Dr. Ramesh argues that microchip implantation is both possible and, for some purposes, desirable and suggests that now is the time to consider strategies for preventing potentially grievous intrusion into personal privacy

A 5-kW xenon ion thruster lifetest

The results of the first life test of a high power ring-cusp ion thruster are presented. A 30-cm laboratory model thruster was operated steady-state at a nominal beam power of 5 kW on xenon propellant for approximately 900 hours. This test was conducted to identify life-timing erosion modifications, and to demonstrate operation using simplified power processing. The results from this test are described including the conclusions derived from extensive post-test analyses of the thruster. Modifications to the thruster and ground support equipment, which were incorporated to solve problems identified by the lifetest, are also described