ASSESSMENT OF SMARTPHONE-BASED TECHNOLOGY FOR REMOTE ENVIRONMENTAL MONITORING AND ITS DEVELOPMENT

Abstract

Many countries are increasing their research on monitoring technology to identify and systematically manage various domestic changes. In particular, the need for remote monitoring is increasing in response to climatic disasters, such as flooding, storms, and rising tides caused by global warming. We developed a smartphone-based environmental monitoring system that enables remote monitoring in any place and at any time. The overall system is composed of a 24-hour smartphone-based imaging system, a monitoring information management system to receive the monitoring information, and stereo image rectification software that provides lens distortion correction, geometric correction, and stereo matching of the monitoring images. The system was developed using the Samsung Galaxy S with the Android OS, as well as open source–based software and other hardware. It is easy to install, control remotely, and monitor the status of imaging devices. We assessed the accuracy of the micro-electro-mechanical system (MEMS) sensors of the smartphone to evaluate the applicability of our environmental monitoring system. The assessment was conducted via survey using metric cameras, a global positioning system receiver, a three-dimensional laser scanner and total station, geometric correction, and digital elevation models generated with camera internal elements, external elements, and ground control points. We demonstrated the effectiveness of the system, and showed that the accuracy of the MEMS sensor and camera calibration have a significant effect on image analysis.

Keywords:

• automated camera system
• environmental monitoring
• remote monitoring system
• smartphone

ACKNOWLEDGMENTS

This research was a part of the project (No. D10503311H4100001E0) titled Yeongnam Seagrant funded by the Ministry of Land, Transport and Maritime Affairs, Korea. Also, this work was partially researched by the supporting project to educate GIS.

Notes

^a Accuracy according to the manufacturer's technical specifications.

^b Accuracy calculated from the field experiment.

^a Settings for saving or not saving.

^b Settings for receiving or not receiving SMS remote-control information.

^c Settings for sending or not sending.

^d Settings for running or not running the app after the Android OS has booted up.

^a Available when connected to separate equipment.

^b Available for free under a two-year subscription contract in Korea.

^c Because the size of the monitoring equipment is small, it can be installed in a narrow space.

^d There is no need for a separate power supply and operating space for the monitoring equipment.

^e Space rental required to operate the monitoring system.

^f Megapixels.

^g How to set the image-capture information (image-capture interval and other items) for the monitoring equipment.

^h A storage can be selected free by a user.

^a Rollei d7 digital camera manufactured by Rollei, Germany.

^b Rollei d30 digital camera manufactured by Rollei, Germany.

^c Samsung Galaxy S manufactured by Samsung Electronics, Korea.

^a Difference between the exterior orientation information calculated directly by the app.

^a Deviation of the exterior orientation information for S _Left and S _Right calculated directly by the app and by LPS.

^a When only the exterior orientation parameters of the cameras were considered, while the interior orientation information was neglected.

^b When both the smartphone interior orientation parameters and exterior orientation parameters were considered.

^c When only the GCPs were considered in SIR, and the interior orientation parameters of the smartphone cameras were neglected.

^d When both the interior orientation parameters of the smartphones and the GCP data were considered in SIR.

^e When only the GCPs were considered, and the interior orientation parameters of the metric cameras were neglected.

^f When both the interior orientation parameters of the metric cameras and the GCP data were considered.

^a When only the exterior orientation parameters of the cameras were considered, while the interior orientation information was neglected.

^b When both the smartphone interior orientation parameters and exterior orientation parameters were considered.

^c When only the GCPs were considered in SIR, and the interior orientation parameters of the smartphone cameras were neglected.

^d When both the interior orientation parameters of the smartphones and the GCP data were considered in SIR.

^e When only the GCPs were considered, and the interior orientation parameters of the metric cameras were neglected.

^f When both the interior orientation parameters of the metric cameras and the GCP data were considered.

^g Differences between the DEMs generated from images geometrically corrected by each procedure and the TLS DEM.