scholarly journals Night sky quality monitoring in existing and planned dark sky parks by digital cameras

2017 ◽  
Vol 19 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Zoltán Kolláth ◽  
Anita Dömény
Keyword(s):  
Objective Measurement ◽  
Quality Monitoring ◽  
Wide Angle ◽  
Digital Cameras ◽  
Night Time ◽  
Mosaic Image ◽  
Wide Angle Lens ◽  
Night Sky ◽  
Crucial Part

A crucial part of the qualification of international dark sky places (IDSPs) is the objective measurement of night time sky luminance or radiance. Modern digital cameras provide an alternative way to perform all sky imaging either by a fisheye lens or by a mosaic image taken by a wide angle lens. Here we present a method for processing raw camera images to obtain calibrated measurements of sky quality. The comparison of the night sky quality of different European locations is also presented to demonstrate the use of our technique.

scholarly journals EVALUATION OF THE QUALITY OF ACTION CAMERAS WITH WIDE-ANGLE LENSES IN UAV PHOTOGRAMMETRY

2016 ◽  
Vol XLI-B1 ◽  
pp. 851-859 ◽  
Author(s):  
H. Hastedt ◽  
T. Ekkel ◽  
T. Luhmann
Keyword(s):  
Eye Lens ◽  
Experimental Setup ◽  
Light Weight ◽  
Wide Angle ◽  
Control Points ◽  
Wide Angle Lens ◽  
Standard Calibration ◽  
Normal Lens ◽  
Fish Eye

The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens) offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

scholarly journals EVALUATION OF THE QUALITY OF ACTION CAMERAS WITH WIDE-ANGLE LENSES IN UAV PHOTOGRAMMETRY

2016 ◽  
Vol XLI-B1 ◽  
pp. 851-859 ◽  
Author(s):  
H. Hastedt ◽  
T. Ekkel ◽  
T. Luhmann
Keyword(s):  
Eye Lens ◽  
Experimental Setup ◽  
Light Weight ◽  
Wide Angle ◽  
Control Points ◽  
Wide Angle Lens ◽  
Standard Calibration ◽  
Normal Lens ◽  
Fish Eye

The application of light-weight cameras in UAV photogrammetry is required due to restrictions in payload. In general, consumer cameras with normal lens type are applied to a UAV system. The availability of action cameras, like the GoPro Hero4 Black, including a wide-angle lens (fish-eye lens) offers new perspectives in UAV projects. With these investigations, different calibration procedures for fish-eye lenses are evaluated in order to quantify their accuracy potential in UAV photogrammetry. Herewith the GoPro Hero4 is evaluated using different acquisition modes. It is investigated to which extent the standard calibration approaches in OpenCV or Agisoft PhotoScan/Lens can be applied to the evaluation processes in UAV photogrammetry. Therefore different calibration setups and processing procedures are assessed and discussed. Additionally a pre-correction of the initial distortion by GoPro Studio and its application to the photogrammetric purposes will be evaluated. An experimental setup with a set of control points and a prospective flight scenario is chosen to evaluate the processing results using Agisoft PhotoScan. Herewith it is analysed to which extent a pre-calibration and pre-correction of a GoPro Hero4 will reinforce the reliability and accuracy of a flight scenario.

Developmental Risk Through a Wide-Angle Lens

1987 ◽  
Vol 32 (1) ◽  
pp. 54-55
Author(s):  
Jack P. Shonkoff
Keyword(s):  
Wide Angle ◽  
Developmental Risk ◽  
Wide Angle Lens

Automatic buffer capacity based sensor for effluent quality monitoring

1996 ◽  
Vol 33 (1) ◽  
pp. 81-87
Author(s):  
L. Van Vooren ◽  
P. Willems ◽  
J. P. Ottoy ◽  
G. C. Vansteenkiste ◽  
W. Verstraete
Keyword(s):  
Wastewater Treatment ◽  
Buffer Capacity ◽  
Wastewater Treatment Plants ◽  
Data Interpretation ◽  
Full Scale ◽  
Quality Monitoring ◽  
Effluent Quality ◽  
Capacity Curves ◽  
On Line

The use of an automatic on-line titration unit for monitoring the effluent quality of wastewater plants is presented. Buffer capacity curves of different effluent types were studied and validation results are presented for both domestic and industrial full-scale wastewater treatment plants. Ammonium and ortho-phosphate monitoring of the effluent were established by using a simple titration device, connected to a data-interpretation unit. The use of this sensor as the activator of an effluent quality proportional sampler is discussed.

scholarly journals Occlusion Culling for Wide-Angle Computer-Generated Holograms Using Phase Added Stereogram Technique

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 298
Author(s):  
Juan Martinez-Carranza ◽  
Tomasz Kozacki ◽  
Rafał Kukołowicz ◽  
Maksymilian Chlipala ◽  
Moncy Sajeev Idicula
Keyword(s):  
Point Sources ◽  
Wide Angle ◽  
Computer Generated Holograms ◽  
Propagation Methods ◽  
Propagation Technique ◽  
3D Scene ◽  
Occlusion Culling ◽  
Fourier Type ◽  
Cloud Of Points

A computer-generated hologram (CGH) allows synthetizing view of 3D scene of real or virtual objects. Additionally, CGH with wide-angle view offers the possibility of having a 3D experience for large objects. An important feature to consider in the calculation of CGHs is occlusion between surfaces because it provides correct perception of encoded 3D scenes. Although there is a vast family of occlusion culling algorithms, none of these, at the best of our knowledge, consider occlusion when calculating CGHs with wide-angle view. For that reason, in this work we propose an occlusion culling algorithm for wide-angle CGHs that uses the Fourier-type phase added stereogram (PAS). It is shown that segmentation properties of the PAS can be used for setting efficient conditions for occlusion culling of hidden areas. The method is efficient because it enables processing of dense cloud of points. The investigated case has 24 million of point sources. Moreover, quality of the occluded wide-angle CGHs is tested by two propagation methods. The first propagation technique quantifies quality of point reproduction of calculated CGH, while the second method enables the quality assessment of the occlusion culling operation over an object of complex shape. Finally, the applicability of proposed occlusion PAS algorithm is tested by synthetizing wide-angle CGHs that are numerically and optically reconstructed.

scholarly journals Prevalence of nocturia among community-dwelling adults: a population-based study in Malaysia

BMC Urology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hui-Yin Yow ◽  
John Jeh Lung Tiong ◽  
Chun-Wai Mai ◽  
Esther van der Werf ◽  
Zulkifli Md Zainuddin ◽  
...  
Keyword(s):  
Medical Condition ◽  
Population Based ◽  
Community Dwelling ◽  
Medical Attention ◽  
Night Time ◽  
Cross Sectional ◽  
Population Based Study ◽  
Waking Up ◽  
The Impact

Abstract Background Nocturia is widely prevalent condition with detrimental effects on quality of life and general health. In Malaysia, there is a lack of up-to-date prevalence study on nocturia. This study aimed to investigate the prevalence of nocturia and awareness pertaining to nocturia among Malaysian adults. Methods A cross-sectional population-based study was conducted among Malaysian adults aged ≥ 18 years old. The data was collected by mixed mode self-administered questionnaire from May 2019 to September 2019. Nocturia was defined as one or more voids at night. Results There were a total of 4616 respondents with 74.5% of response rate. The overall prevalence of nocturia among Malaysian adults was found to be 57.3%. In multivariate analysis, respondents aged 31–40 (1.91 [1.52–2.40]) or > 60 years old (2.03 [1.48–2.71]), and those who presented with hypertension (2.84 [2.28–3.53]), diabetes mellitus (1.78 [1.42–2.25]), renal disease (3.58 [1.93–6.63]) or overactive bladder (1.61 [1.10–2.35]) were associated with higher prevalence of nocturia. A significantly lower disease prevalence (p < 0.05) was noted among those aged 41–50 (0.73 [0.59–0.91]), male (0.78 [0.69–0.88]) and Chinese (0.47 [0.30–0.74]) or Indian (0.34 [0.21–0.54]) ethnicities. A total of 37.3% of respondents with nocturia reported that they faced sleeping difficulty about half the time or more after waking up in the middle of night. Those who had ≥ 2 voids per night experienced significantly higher mean bother score than those who had 1 void per night (p < 0.001). Approximately half (56.7%) of all respondents were not aware that night time urination is a medical condition. Only 25.2% of respondents with nocturia had sought medical attention for their nocturia. Conclusions The prevalence of nocturia among Malaysian adults is high and strongly influenced by age, sex, race and comorbidities. However, the general awareness pertaining to nocturia being a health issue remains low among Malaysians. The findings also highlighted the impact of nocturia on sleep and the need for nocturia education to better address this disease.

Quality Monitoring System for Seismic While Drilling

2013 ◽  
Vol 318 ◽  
pp. 572-575
Author(s):  
Li Li Yu ◽  
Yu Hong Li ◽  
Ai Feng Wang
Keyword(s):  
Data Acquisition ◽  
Monitoring System ◽  
Signal Analysis ◽  
Quality Evaluation ◽  
Quality Monitoring ◽  
Quality Of Data ◽  
Whole Process ◽  
Engineering Parameters ◽  
Network Status

In this paper a quality monitoring system for seismic while drilling (SWD) that integrates the whole process of data acquisition was developed. The acquisition equipment, network status and signals of accelerometer and geophone were monitored real-time. With fast signal analysis and quality evaluation, the acquisition parameters and drilling engineering parameters can be adjusted timely. The application of the system can improve the quality of data acquisition and provide subsequent processing and interpretation with high qualified reliable data.

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