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Author Burggraaff, O., Schmidt, N., Zamorano, J., Pauly, K., Pascual, S., Tapia, C., Spyrakos, E., & Snik, F. url  openurl
  Title Standardized spectral and radiometric calibration of consumer cameras Type Journal Article
  Year 2019 Publication Optical Express Abbreviated Journal  
  Volume 27 Issue 14 Pages 19075-19101  
  Keywords Instrumentation  
  Abstract Consumer cameras, particularly onboard smartphones and UAVs, are now commonly used as scientific instruments. However, their data processing pipelines are not optimized for quantitative radiometry and their calibration is more complex than that of scientific cameras. The lack of a standardized calibration methodology limits the interoperability between devices and, in the ever-changing market, ultimately the lifespan of projects using them. We present a standardized methodology and database (SPECTACLE) for spectral and radiometric calibrations of consumer cameras, including linearity, bias variations, read-out noise, dark current, ISO speed and gain, flat-field, and RGB spectral response. This includes golden standard ground-truth methods and do-it-yourself methods suitable for non-experts. Applying this methodology to seven popular cameras, we found high linearity in RAW but not JPEG data, inter-pixel gain variations >400% correlated with large-scale bias and read-out noise patterns, non-trivial ISO speed normalization functions, flat-field correction factors varying by up to 2.79 over the field of view, and both similarities and differences in spectral response. Moreover, these results differed wildly between camera models, highlighting the importance of standardization and a centralized database.  
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  Notes Approved no  
  Call Number IDA @ intern @ Serial 2652  
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Author Gu, Y., Uprety, S., Blonski, S., Zhang, B., & Cao, C. url  doi
openurl 
  Title Improved algorithm for determining the Visible Infrared Imaging Radiometer Suite Day/Night Band high-gain stage dark offset free from light contamination Type Journal Article
  Year 2019 Publication Applied Optics Abbreviated Journal  
  Volume 58 Issue 6 Pages 1400-1407  
  Keywords Remote Sensing; Instrumentation  
  Abstract Dark offset is one of the key parameters for Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) high-gain stage (HGS) radiometric calibration, whose accuracy strongly impacts applications of DNB low-light detection for Earth observation at nighttime. Currently, DNB observation of the VIIRS onboard calibrator blackbody (OBCBB) view, together with its observation of deep space during the spacecraft pitch maneuver performed early in the mission, has been used to compute the HGS dark offset continuously. However, the relationship between the DNB OBCBB data and the Earth view (EV) data is unclear due to electronic timing differences between these two views. It is questionable whether the DNB OBCBB data can monitor the EV HGS dark offset change. Through comprehensive analysis of the DNB OBCBB data and EV data acquired from the monthly special acquisitions known as the VIIRS recommended operating procedures (VROPs), we have shown that the OBCBB data can only track the dark current component of the DNB HGS EV dark offset, instead of the total dark offset. The DNB observation of deep space during the spacecraft pitch maneuver was also contaminated by starlight. With such background, in this paper we propose an improved algorithm for determining the DNB HGS dark offset. By combined use of the DNB OBCBB data and the DNB VROP data, the generated DNB HGS dark offset is both free from light contamination and capable of tracking continuous drift. The improved algorithm could potentially improve the DNB radiometric performance at low radiance level. Our results provide a solid theoretical basis for dark offset calibration of the VIIRS DNB onboard Suomi National Polar-Orbiting Partnership satellite and the following Joint Polar Satellite System satellites.  
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  Notes Approved no  
  Call Number IDA @ intern @ Serial 2358  
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Author Tauc, M.J.; Fristrup, K.M.; Repasky, K.S.; Shaw, J.A. url  doi
openurl 
  Title Field demonstration of a wing-beat modulation lidar for the 3D mapping of flying insects Type Journal Article
  Year 2019 Publication OSA Continuum Abbreviated Journal OSA Continuum  
  Volume 2 Issue 2 Pages 332  
  Keywords Instrumentation; Animals  
  Abstract We describe a wing-beat modulation lidar system designed for the 3D mapping of flying insects in ecological or entomological studies. To better understand the signals from this instrument, we analyzed simulated signals to identify how they were affected by various imperfections, such as variations in the spacing and amplitude of each individual wing-beat reflection. In addition, a radiometric model was used to estimate signal-to-noise ratio to gain insight into the relationships between the optical system design and insect parameters (e.g., wing size, reflectivity, or diffusivity).  
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  Series Volume Series Issue Edition  
  ISSN 2578-7519 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2209  
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Author Yao, Q.; Wang, H.; Dai, Q.; Shi, F. url  doi
openurl 
  Title Quantification assessment of light pollution of façade lighting display in Shenzhen, China Type Journal Article
  Year 2020 Publication Optics Express Abbreviated Journal Opt. Express  
  Volume 28 Issue 9 Pages 14100  
  Keywords Lighting; Instrumentation  
  Abstract In this work, we investigated 39 façade lighting displays, all of which consisted of tri-chromatic light sources, namely blue-, green-, and red- light units, in Shenzhen, China. We extracted the spectral characteristics of the mean peak wavelength/full-width at half-maximum,and proposed universal spectral models. We further established the ‘chromaticity-performance’ relation to quantitatively assess the impact of light pollution on typical species based on corresponding action spectra. The findings provide a low-cost, fast and precise approach to assess light pollution of complicated light environment, and may help reduce energy waste and adverse environmental consequences associated with light pollution.  
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  ISSN 1094-4087 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2893  
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Author Babadi, S.; Ramirez-Inguiez, R.; Boutaleb, T.; Mallick, T. url  doi
openurl 
  Title Producing uniform illumination within a rectangular area by using a nonimaging optic Type Journal Article
  Year 2018 Publication Applied Optics Abbreviated Journal Appl. Opt.  
  Volume 57 Issue 31 Pages 9357  
  Keywords Lighting  
  Abstract This paper proposes a new design method to create a novel optical element to generate uniform illumination within a rectangular area. Based on this model, an illuminated area is irradiated by two sets of rays; the first one irradiates the target plane after refraction from the top section of the lens, and the second one irradiates from the reflection at the side profile of the lens and then from refraction at the top part of the lens. The results show that a uniformity of over 90% can be achieved.  
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  Series Volume Series Issue Edition  
  ISSN 1559-128X ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2046  
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