CALIBRACIÓN DE TELÉFONOS INTELIGENTES PARA LA MEDICIÓN DE ILUMINACIÓN DE ESPACIOS INTERIORES

Abstract

The objective of this study is to propose calibration criteria in order to minimize illuminance measurement errors using mobile phones, upon a systematic comparison with a gold standard. Readings from of a professional luxmeter were compared with the illuminance readings of four Android applications for lighting measurement, installed on two mobile devices, at 17 illuminance levels, from 20 lx to 20 lx. 10,000 lx varying the distance to a single light source (LED 24W 6000K, CRI> 70). The direct reading error was calculated by device and by application, whose averages were between 28.36% and 41.77%. There was interdevice and inter-application variability, which was not statistically significant. Then, two novel calibration criteria were applied: The first one was based on a single correction factor, which was calculated from the mean value of the illuminance range in this study. With this criterion, we achieved a mean error of -0.45% (SD = 1.60). The second criterion used a power function to adjust the data from the mobile device to the gold standard, achieving an average error of -0.08% (SD = 0.21). Our results were better than those obtained through the minimum value criterion found in previous studies. We discussed the pros and cons of both calibration criteria, then we presented insights regarding the tolerable error for different practical situations. The goal is to achieve by means of a mobile device, an error comparable to the one obtained with a low-cost light meter.