Machine Learning-Based Calibration of Low-Cost Air Temperature Sensors Using Environmental Data
1
PS Solutions Corp., 1-5-2 Higashi-Shimbashi, Minato-ku, Tokyo 105-7104, Japan
2
Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Midori-cho, Nishi-Tokyo, Tokyo 188-0002, Japan
*
Author to whom correspondence should be addressed.
Academic Editor: Vittorio M. N. Passaro
Sensors 2017, 17(6), 1290; https://doi.org/10.3390/s17061290
Received: 6 January 2017
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Revised: 27 May 2017
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Accepted: 31 May 2017
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Published: 5 June 2017
(This article belongs to the Section Sensor Networks)
The measurement of air temperature is strongly influenced by environmental factors such as solar radiation, humidity, wind speed and rainfall. This is problematic in low-cost air temperature sensors, which lack a radiation shield or a forced aspiration system, exposing them to direct sunlight and condensation. In this study, we developed a machine learning-based calibration method for air temperature measurement by a low-cost sensor. An artificial neural network (ANN) was used to balance the effect of multiple environmental factors on the measurements. Data were collected over 305 days, at three different locations in Japan, and used to evaluate the performance of the approach. Data collected at the same location and at different locations were used for training and testing, and the former was also used for k-fold cross-validation, demonstrating an average improvement in mean absolute error (MAE) from 1.62 to 0.67 by applying our method. Some calibration failures were noted, due to abrupt changes in environmental conditions such as solar radiation or rainfall. The MAE was shown to decrease even when the data collected in different nearby locations were used for training and testing. However, the results also showed that negative effects arose when data obtained from widely-separated locations were used, because of the significant environmental differences between them.
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Keywords:
sensor calibration; low-cost sensor; machine learning; artificial neural network; agriculture
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Doi: doi:10.5281/zenodo.571258
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MDPI and ACS Style
Yamamoto, K.; Togami, T.; Yamaguchi, N.; Ninomiya, S. Machine Learning-Based Calibration of Low-Cost Air Temperature Sensors Using Environmental Data. Sensors 2017, 17, 1290. https://doi.org/10.3390/s17061290
AMA Style
Yamamoto K, Togami T, Yamaguchi N, Ninomiya S. Machine Learning-Based Calibration of Low-Cost Air Temperature Sensors Using Environmental Data. Sensors. 2017; 17(6):1290. https://doi.org/10.3390/s17061290
Chicago/Turabian StyleYamamoto, Kyosuke, Takashi Togami, Norio Yamaguchi, and Seishi Ninomiya. 2017. "Machine Learning-Based Calibration of Low-Cost Air Temperature Sensors Using Environmental Data" Sensors 17, no. 6: 1290. https://doi.org/10.3390/s17061290
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