scholarly journals Characterization of linear light sources with the smartphone’s ambient light sensor

2018 ◽  
Vol 56 (8) ◽  
pp. 562-563 ◽  
Author(s):  
Isabel Salinas ◽  
Marcos H. Giménez ◽  
Juan A. Monsoriu ◽  
Juan C. Castro-Palacio
2021 ◽  
Vol 11 (16) ◽  
pp. 7566
Author(s):  
Rosa María Salmerón-Campillo ◽  
Arthur Bradley ◽  
Mateusz Jaskulski ◽  
Norberto López-Gil

Introduction: To uncover a relationship between light exposure and myopia is complicated because of the challenging nature of measuring visually relevant illumination experienced by children. Objective: To find a methodology to measure face illuminance using a mobile device. Methods: Accuracy and precision of the mobile device’s built-in ambient light sensor were tested under three different lighting conditions: full-field, a single small light, and one mimicking typical office illumination. Face illuminance was computed in six faces with different skin reflectances using pixel values in face images captured by the device camera placed at 30 cm in front of the face. The results were compared with those obtained with a commercial light meter situated at the face. Results: The illuminance measured by the device’s ambient light sensor showed high linearity (R2 > 0.99) slightly under-estimating or conversely over-estimating face illuminance with full-field or single light sources but accurate for office lighting. Face illuminance measured by the devices’ camera under indoor conditions using the new methodology showed a mean relative error of 27% and a high linearity (R2 > 0.94). Conclusions: Introduction of an app can be used to assess the association between visually relevant environmental light levels and myopia progression.


2018 ◽  
Vol 197 ◽  
pp. 02003 ◽  
Author(s):  
Ea Cahya Septia Mahen ◽  
Seni Susanti ◽  
Bebeh Wahid Nuryadin ◽  
Ade Yeti Nuryantini

This paper reports on the result of a preliminary study of utilization of a smartphone ambient light sensor for get the average speeds of motion along a straight line based on experiments. We attach a smartphone to a dynamics train that travels across multiple light sources where the distance is already set. The main source of this experiment is obtained from the luminosity curve obtained from free android applications. From the curve, we can get position information against time. So from the data we can get the value of average speed. Then the use of the smartphone light sensor in physics experiments can be done easily and fun.


2010 ◽  
Vol E93-C (11) ◽  
pp. 1583-1589
Author(s):  
Fumirou MATSUKI ◽  
Kazuyuki HASHIMOTO ◽  
Keiichi SANO ◽  
Fu-Yuan HSUEH ◽  
Ramesh KAKKAD ◽  
...  

2019 ◽  
Vol E102.C (7) ◽  
pp. 558-564
Author(s):  
Takashi NAKAMURA ◽  
Masahiro TADA ◽  
Hiroyuki KIMURA

2019 ◽  
Author(s):  
Jeremy E. Solbrig ◽  
Steven D. Miller ◽  
Jianglong Zhang ◽  
Lewis Grasso ◽  
Anton Kliewer

Abstract. Detection and characterization of aerosols is inherently limited at night due to a lack of sensitivity—information typically provided by visible spectrum observations. The VIIRS Day/Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible/near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for retrieval of atmospheric properties including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Timeseries are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially-resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation


2021 ◽  
Author(s):  
Kojiro Abe ◽  
Takuto Sato ◽  
Hiroki Watanabe ◽  
Hiromichi Hashizume ◽  
Masanori Sugimoto

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