- home
- Search
Filters
Clear AllYear range
-chevron_right GOField of Science
Country
Research community
- Rural Digital Europe
- Applied Optics
- Rural Digital Europe
- Applied Optics
Loading
description Publicationkeyboard_double_arrow_right Article 2017Publisher:The Optical Society Authors: Shuowen, Hu; Geoffrey H, Goldman; Christoph C, Borel-Donohue;Shuowen, Hu; Geoffrey H, Goldman; Christoph C, Borel-Donohue;doi: 10.1364/ao.56.00b214
pmid: 28157904
Unmanned aerial vehicles (UAVs) flown by adversaries are an emerging asymmetric threat to homeland security and the military. To help address this threat, we developed and tested a computationally efficient UAV detection algorithm consisting of horizon finding, motion feature extraction, blob analysis, and coherence analysis. We compare the performance of this algorithm against two variants, one using the difference image intensity as the motion features and another using higher-order moments. The proposed algorithm and its variants are tested using field test data of a group 3 UAV acquired with a panoramic video camera in the visible spectrum. The performance of the algorithms was evaluated using receiver operating characteristic curves. The results show that the proposed approach had the best performance compared to the two algorithmic variants.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.56.00b214&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 33 citations 33 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.56.00b214&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2004Publisher:Optica Publishing Group Authors: Hai-Wen, Chen; Surachai, Sutha; Teresa, Olson;Hai-Wen, Chen; Surachai, Sutha; Teresa, Olson;doi: 10.1364/ao.43.000403
pmid: 14735959
We developed spatiotemporal fusion techniques for improving target detection and automatic target recognition. We also investigated real IR (infrared) sensor clutter noise. The sensor noise was collected by an IR (256 x 256) sensor looking at various scenes (trees, grass, roads, buildings, etc.). More than 95% of the sensor pixels showed near-stationary sensor clutter noise that was uncorrelated between pixels as well as across time frames. However, in a few pixels (covering the grass near the road) the sensor noise showed nonstationary properties (with increasing or decreasing mean across time frames). The natural noise extracted from the IR sensor, as well as the computer-generated noise with Gaussian and Rayleigh distributions, was used to test and compare different spatiotemporal fusion strategies. Finally, we proposed two advanced detection schemes: the double-thresholding the reverse-thresholding techniques. These techniques may be applied to complicated clutter situations (e.g., very-high clutter or nonstationary clutter situations) where the traditional constant-false-alarm-ratio technique may fail.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.43.000403&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 6 citations 6 popularity Average influence Top 10% impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.43.000403&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1983Publisher:Optica Publishing Group Authors: D K, Killinger; N, Menyuk; W E, DeFeo;D K, Killinger; N, Menyuk; W E, DeFeo;doi: 10.1364/ao.22.000682
pmid: 18195856
A pulsed dual-wavelength dual-CO2-laser differential-absorption lidar (DIAL) system has been developed which permits simultaneous heterodyne and direct detection of the same lidar returns. This system has been used to make an experimental comparison of the SNRs and statistical and temporal characteristics of the DIAL returns from several topographic targets. These results were found to be in general agreement with theory and were used to quantify the relative merits of the two detection techniques. The measured parameter values were applied to an analytical treatment to predict system trade-offs for the remote sensing of atmospheric species, with application to both path-averaged and range-resolved measurements.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.22.000682&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 37 citations 37 popularity Average influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.22.000682&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2007Publisher:Optica Publishing Group Karine, Caillault; Sandrine, Fauqueux; Christophe, Bourlier; Pierre, Simoneau; Luc, Labarre;doi: 10.1364/ao.46.005471
pmid: 17676164
An analytical model of sea optical properties has been developed in order to generate sea surface images, as seen by an infrared sensor. This model is based on a statistical approach and integrates the spatial variability of a wind-roughened sea surface whose variability ranges from a 1-m to a kilometer scale. It also takes into account submetric variability. A two-scale approach has been applied by superimposing small scale variability (smaller than the pixel footprint) to larger ones. Introducing multiresolution in the sensor field of view allows the requirement of any observational configuration, including nadir as well as grazing view geometry. The physical background of the methods has been tested against theoretical considerations. We also obtained a good agreement with dataset collections at our disposal and taken from the literature, such that a bias shows up at grazing angles, mainly explained by not taking into account multiple reflections. Applied to the generation of synthetic sea surface radiance images, our model leads to good quality ocean scenes, whatever the contextual conditions.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.46.005471&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 23 citations 23 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.46.005471&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1998Publisher:Optica Publishing Group A F, Bais; S, Kazadzis; D, Balis; C S, Zerefos; M, Blumthaler;doi: 10.1364/ao.37.006339
pmid: 18286132
We present a methodology for correcting the global UV spectral measurements of a Brewer MKIII spectroradiometer for the error introduced by the deviation of the angular response of the instrument from the ideal response. This methodology is applicable also to other Brewer spectroradiometers that are currently in operation. The various stages of the methodology are described in detail, together with the uncertainties involved in each stage. Finally global spectral UV measurements with and without the application of the correction are compared with collocated measurements of another spectroradiometer and with model calculations, demonstrating the efficiency of the method. Depending on wavelength and on the aerosol loading, the cosine correction factors range from 2% to 7%. The uncertainties involved in the calculation of these correction factors were found to be relatively small, ranging from ~0.2% to ~2%.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.37.006339&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 78 citations 78 popularity Average influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.37.006339&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1991Publisher:Optica Publishing Group Authors: K, Stamnes; J, Slusser; M, Bowen;K, Stamnes; J, Slusser; M, Bowen;doi: 10.1364/ao.30.004418
pmid: 20717220
We describe a method to infer total ozone abundance and effective cloud transmission from global (diffuse plus direct) spectral irradiance measurements taken at the Earth's surface. The derivation of total ozone abundance relies on the comparison of measured irradiance ratios at two wavelengths in the UV part of the spectrum with a synthetic chart of this ratio computed for a variety of ozone abundances. One of these wavelengths should be appreciably absorbed by ozone (e.g., 305 nm) compared with the other one (e.g., 340 nm). This synthetic ratio (and therefore also the inferred total ozone abundance) is insensitive to the value of the surface albedo used in the model computations. Comparison with independent in situ and remote (from ground and space) determinations of total ozone abundance shows that measurements of global irradiances provide a reliable means of inferring the total column ozone amount for clear as well as cloudy sky conditions. Computer simulations are used to demonstrate that the ozone abundance inferred from global irradiance measurements is quite insensitive to cloud effects, whereas the use of the scattered irradiance only or the zenith sky intensity (measured routinely in the Dobson network on overcast days) requires substantial corrections for cloud effects. Effective cloud transmission is estimated from the data by comparing the measured irradiance at a wavelength where ozone absorption is minimal (e.g., 350 nm) to the clear-sky value. Irradiances generated by a plane-parallel radiation model as a function of cloud optical thickness are used to estimate an equivalent stratified cloud optical depth. These estimates of cloud transmission and optical depth are sensitive to ground reflection, implying that the accurate determination of cloud attenuation requires precise knowledge of the surface albedo.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.30.004418&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 102 citations 102 popularity Top 10% influence Top 1% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.30.004418&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1972Publisher:Optica Publishing Group Authors: J, Cooney;J, Cooney;doi: 10.1364/ao.11.002374
pmid: 20119339
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.11.002374&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 5 citations 5 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.11.002374&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2008Publisher:Optica Publishing Group Tamer F, Refaat; Syed, Ismail; M Nurul, Abedin; Scott M, Spuler; Shane D, Mayor; Upendra N, Singh;doi: 10.1364/ao.47.005281
pmid: 18846166
Backscatter lidar detection systems have been designed and integrated at NASA Langley Research Center using IR heterojunction phototransistors. The design focused on maximizing the system signal-to-noise ratio rather than noise minimization. The detection systems have been validated using the Raman-shifted eye-safe aerosol lidar (REAL) at the National Center for Atmospheric Research. Incorporating such devices introduces some systematic effects in the form of blurring to the backscattered signals. Characterization of the detection system transfer function aided in recovering such effects by deconvolution. The transfer function was obtained by measuring and fitting the system impulse response using single-pole approximation. An iterative deconvolution algorithm was implemented in order to recover the system resolution, while maintaining high signal-to-noise ratio. Results indicated a full recovery of the lidar signal, with resolution matching avalanche photodiodes. Application of such a technique to atmospheric boundary and cloud layers data restores the range resolution, up to 60 m, and overcomes the blurring effects.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.47.005281&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 8 citations 8 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.47.005281&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1975Publisher:Optica Publishing Group Authors: J J, Horan; D S, Schwartz; J D, Love;J J, Horan; D S, Schwartz; J D, Love;doi: 10.1364/ao.14.002053
pmid: 20154960
Sun calibration data from Landsat-2 are presented and compared with those from Landsat-1 (ERTS-1). The data support the hypothesis that organic contamination caused the poor performance of the Landsat-1 sun calibration mirror, since extra cleanliness precautions were taken with the Landsat-2 mirror. These precautions are described; of particular importance was the aluminum foil covering kept close to the reflective surfaces of the second mirror during the prelaunch period.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.14.002053&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 2 citations 2 popularity Average influence Top 10% impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.14.002053&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2016Publisher:The Optical Society Authors: Monique, Walker; Demetrius, Venable; David N, Whiteman; Tetsu, Sakai;Monique, Walker; Demetrius, Venable; David N, Whiteman; Tetsu, Sakai;doi: 10.1364/ao.55.002551
pmid: 27139656
Traditionally, the lidar water vapor mixing ratio (WVMR) is corrected for overlap using data from another instrument, such as a radiosonde. Here we introduce a new experimental method to determine the overlap function using the lamp mapping technique (LMT), which relies on the lidar optics and detection system. The LMT discussed here involves a standard halogen lamp being scanned over the aperture of a Raman lidar telescope in synchronization with the lidar detection system [Appl. Opt.50, 4622 (2011)APOPAI0003-693510.1364/AO.50.004622, Appl. Opt.53, 8538 (2014)APOPAI0003-693510.1364/AO.53.008535]. In this paper, we show results for a LMT-determined overlap function for individual channels, as well as a WVMR overlap function. We found that the LMT-determined WVMR overlap functions deviate within 5% of the traditional radiosonde-determined overlap.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.55.002551&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.55.002551&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu
Loading
description Publicationkeyboard_double_arrow_right Article 2017Publisher:The Optical Society Authors: Shuowen, Hu; Geoffrey H, Goldman; Christoph C, Borel-Donohue;Shuowen, Hu; Geoffrey H, Goldman; Christoph C, Borel-Donohue;doi: 10.1364/ao.56.00b214
pmid: 28157904
Unmanned aerial vehicles (UAVs) flown by adversaries are an emerging asymmetric threat to homeland security and the military. To help address this threat, we developed and tested a computationally efficient UAV detection algorithm consisting of horizon finding, motion feature extraction, blob analysis, and coherence analysis. We compare the performance of this algorithm against two variants, one using the difference image intensity as the motion features and another using higher-order moments. The proposed algorithm and its variants are tested using field test data of a group 3 UAV acquired with a panoramic video camera in the visible spectrum. The performance of the algorithms was evaluated using receiver operating characteristic curves. The results show that the proposed approach had the best performance compared to the two algorithmic variants.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.56.00b214&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 33 citations 33 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.56.00b214&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2004Publisher:Optica Publishing Group Authors: Hai-Wen, Chen; Surachai, Sutha; Teresa, Olson;Hai-Wen, Chen; Surachai, Sutha; Teresa, Olson;doi: 10.1364/ao.43.000403
pmid: 14735959
We developed spatiotemporal fusion techniques for improving target detection and automatic target recognition. We also investigated real IR (infrared) sensor clutter noise. The sensor noise was collected by an IR (256 x 256) sensor looking at various scenes (trees, grass, roads, buildings, etc.). More than 95% of the sensor pixels showed near-stationary sensor clutter noise that was uncorrelated between pixels as well as across time frames. However, in a few pixels (covering the grass near the road) the sensor noise showed nonstationary properties (with increasing or decreasing mean across time frames). The natural noise extracted from the IR sensor, as well as the computer-generated noise with Gaussian and Rayleigh distributions, was used to test and compare different spatiotemporal fusion strategies. Finally, we proposed two advanced detection schemes: the double-thresholding the reverse-thresholding techniques. These techniques may be applied to complicated clutter situations (e.g., very-high clutter or nonstationary clutter situations) where the traditional constant-false-alarm-ratio technique may fail.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.43.000403&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 6 citations 6 popularity Average influence Top 10% impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.43.000403&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1983Publisher:Optica Publishing Group Authors: D K, Killinger; N, Menyuk; W E, DeFeo;D K, Killinger; N, Menyuk; W E, DeFeo;doi: 10.1364/ao.22.000682
pmid: 18195856
A pulsed dual-wavelength dual-CO2-laser differential-absorption lidar (DIAL) system has been developed which permits simultaneous heterodyne and direct detection of the same lidar returns. This system has been used to make an experimental comparison of the SNRs and statistical and temporal characteristics of the DIAL returns from several topographic targets. These results were found to be in general agreement with theory and were used to quantify the relative merits of the two detection techniques. The measured parameter values were applied to an analytical treatment to predict system trade-offs for the remote sensing of atmospheric species, with application to both path-averaged and range-resolved measurements.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.22.000682&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 37 citations 37 popularity Average influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.22.000682&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2007Publisher:Optica Publishing Group Karine, Caillault; Sandrine, Fauqueux; Christophe, Bourlier; Pierre, Simoneau; Luc, Labarre;doi: 10.1364/ao.46.005471
pmid: 17676164
An analytical model of sea optical properties has been developed in order to generate sea surface images, as seen by an infrared sensor. This model is based on a statistical approach and integrates the spatial variability of a wind-roughened sea surface whose variability ranges from a 1-m to a kilometer scale. It also takes into account submetric variability. A two-scale approach has been applied by superimposing small scale variability (smaller than the pixel footprint) to larger ones. Introducing multiresolution in the sensor field of view allows the requirement of any observational configuration, including nadir as well as grazing view geometry. The physical background of the methods has been tested against theoretical considerations. We also obtained a good agreement with dataset collections at our disposal and taken from the literature, such that a bias shows up at grazing angles, mainly explained by not taking into account multiple reflections. Applied to the generation of synthetic sea surface radiance images, our model leads to good quality ocean scenes, whatever the contextual conditions.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.46.005471&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 23 citations 23 popularity Top 10% influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.46.005471&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1998Publisher:Optica Publishing Group A F, Bais; S, Kazadzis; D, Balis; C S, Zerefos; M, Blumthaler;doi: 10.1364/ao.37.006339
pmid: 18286132
We present a methodology for correcting the global UV spectral measurements of a Brewer MKIII spectroradiometer for the error introduced by the deviation of the angular response of the instrument from the ideal response. This methodology is applicable also to other Brewer spectroradiometers that are currently in operation. The various stages of the methodology are described in detail, together with the uncertainties involved in each stage. Finally global spectral UV measurements with and without the application of the correction are compared with collocated measurements of another spectroradiometer and with model calculations, demonstrating the efficiency of the method. Depending on wavelength and on the aerosol loading, the cosine correction factors range from 2% to 7%. The uncertainties involved in the calculation of these correction factors were found to be relatively small, ranging from ~0.2% to ~2%.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.37.006339&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 78 citations 78 popularity Average influence Top 10% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.37.006339&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1991Publisher:Optica Publishing Group Authors: K, Stamnes; J, Slusser; M, Bowen;K, Stamnes; J, Slusser; M, Bowen;doi: 10.1364/ao.30.004418
pmid: 20717220
We describe a method to infer total ozone abundance and effective cloud transmission from global (diffuse plus direct) spectral irradiance measurements taken at the Earth's surface. The derivation of total ozone abundance relies on the comparison of measured irradiance ratios at two wavelengths in the UV part of the spectrum with a synthetic chart of this ratio computed for a variety of ozone abundances. One of these wavelengths should be appreciably absorbed by ozone (e.g., 305 nm) compared with the other one (e.g., 340 nm). This synthetic ratio (and therefore also the inferred total ozone abundance) is insensitive to the value of the surface albedo used in the model computations. Comparison with independent in situ and remote (from ground and space) determinations of total ozone abundance shows that measurements of global irradiances provide a reliable means of inferring the total column ozone amount for clear as well as cloudy sky conditions. Computer simulations are used to demonstrate that the ozone abundance inferred from global irradiance measurements is quite insensitive to cloud effects, whereas the use of the scattered irradiance only or the zenith sky intensity (measured routinely in the Dobson network on overcast days) requires substantial corrections for cloud effects. Effective cloud transmission is estimated from the data by comparing the measured irradiance at a wavelength where ozone absorption is minimal (e.g., 350 nm) to the clear-sky value. Irradiances generated by a plane-parallel radiation model as a function of cloud optical thickness are used to estimate an equivalent stratified cloud optical depth. These estimates of cloud transmission and optical depth are sensitive to ground reflection, implying that the accurate determination of cloud attenuation requires precise knowledge of the surface albedo.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.30.004418&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 102 citations 102 popularity Top 10% influence Top 1% impulse Top 10% Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.30.004418&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1972Publisher:Optica Publishing Group Authors: J, Cooney;J, Cooney;doi: 10.1364/ao.11.002374
pmid: 20119339
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.11.002374&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 5 citations 5 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.11.002374&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2008Publisher:Optica Publishing Group Tamer F, Refaat; Syed, Ismail; M Nurul, Abedin; Scott M, Spuler; Shane D, Mayor; Upendra N, Singh;doi: 10.1364/ao.47.005281
pmid: 18846166
Backscatter lidar detection systems have been designed and integrated at NASA Langley Research Center using IR heterojunction phototransistors. The design focused on maximizing the system signal-to-noise ratio rather than noise minimization. The detection systems have been validated using the Raman-shifted eye-safe aerosol lidar (REAL) at the National Center for Atmospheric Research. Incorporating such devices introduces some systematic effects in the form of blurring to the backscattered signals. Characterization of the detection system transfer function aided in recovering such effects by deconvolution. The transfer function was obtained by measuring and fitting the system impulse response using single-pole approximation. An iterative deconvolution algorithm was implemented in order to recover the system resolution, while maintaining high signal-to-noise ratio. Results indicated a full recovery of the lidar signal, with resolution matching avalanche photodiodes. Application of such a technique to atmospheric boundary and cloud layers data restores the range resolution, up to 60 m, and overcomes the blurring effects.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.47.005281&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 8 citations 8 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.47.005281&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 1975Publisher:Optica Publishing Group Authors: J J, Horan; D S, Schwartz; J D, Love;J J, Horan; D S, Schwartz; J D, Love;doi: 10.1364/ao.14.002053
pmid: 20154960
Sun calibration data from Landsat-2 are presented and compared with those from Landsat-1 (ERTS-1). The data support the hypothesis that organic contamination caused the poor performance of the Landsat-1 sun calibration mirror, since extra cleanliness precautions were taken with the Landsat-2 mirror. These precautions are described; of particular importance was the aluminum foil covering kept close to the reflective surfaces of the second mirror during the prelaunch period.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.14.002053&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 2 citations 2 popularity Average influence Top 10% impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.14.002053&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eudescription Publicationkeyboard_double_arrow_right Article 2016Publisher:The Optical Society Authors: Monique, Walker; Demetrius, Venable; David N, Whiteman; Tetsu, Sakai;Monique, Walker; Demetrius, Venable; David N, Whiteman; Tetsu, Sakai;doi: 10.1364/ao.55.002551
pmid: 27139656
Traditionally, the lidar water vapor mixing ratio (WVMR) is corrected for overlap using data from another instrument, such as a radiosonde. Here we introduce a new experimental method to determine the overlap function using the lamp mapping technique (LMT), which relies on the lidar optics and detection system. The LMT discussed here involves a standard halogen lamp being scanned over the aperture of a Raman lidar telescope in synchronization with the lidar detection system [Appl. Opt.50, 4622 (2011)APOPAI0003-693510.1364/AO.50.004622, Appl. Opt.53, 8538 (2014)APOPAI0003-693510.1364/AO.53.008535]. In this paper, we show results for a LMT-determined overlap function for individual channels, as well as a WVMR overlap function. We found that the LMT-determined WVMR overlap functions deviate within 5% of the traditional radiosonde-determined overlap.
add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.55.002551&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.euAccess Routesbronze 2 citations 2 popularity Average influence Average impulse Average Powered by BIP!more_vert add ClaimPlease grant OpenAIRE to access and update your ORCID works.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.This Research product is the result of merged Research products in OpenAIRE.
You have already added works in your ORCID record related to the merged Research product.All Research productsarrow_drop_down <script type="text/javascript"> <!-- document.write('<div id="oa_widget"></div>'); document.write('<script type="text/javascript" src="https://www.openaire.eu/index.php?option=com_openaire&view=widget&format=raw&projectId=10.1364/ao.55.002551&type=result"></script>'); --> </script>
For further information contact us at helpdesk@openaire.eu