An Ontology for Spatio-Temporal Media Management and an Interactive Application

Sone, Takuro; Shin, Kato; Atarashi, Ray; Nakazato, Jin; Tsukada, Manabu; Esaki, Hiroshi

doi:10.3390/fi15070225

Cited by 3 publications

(1 citation statement)

References 41 publications

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“…In Section 1, we discussed the lack of a standard mechanism for recording highly accurate location and time information in combination with media data. SDM Ontology [14] is the result of work done by another research team, including the first author, to address this issue. SDM Ontology is a spatio-temporal media ontology for comprehensively recording various metadata and media data.…”

Section: Related Workmentioning

confidence: 99%

A mobile recording system featuring high-precision time synchronization

Sone,

Maeda,

Kitani

2023

The Evolving Scholar - BMD 2023, 5th Edition

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In order to accurately integrate data measured and recorded by combining multiple data loggers and video/audio recording devices in a mobile environment and extract valid information, the location and time information at which data was recorded must be recorded with sufficient accuracy. In recent years, it has become relatively easy to obtain location information with accuracy on the order of cm by using high-precision satellite positioning such as RTK-GNSS. On the other hand, in many cases, a time accuracy of approximately 1 ms or less is required to integrate data recorded while the recording device or recording target is moving and to determine the position with cm-order accuracy. In data recording by simple data loggers, commercially available video cameras, smartphones, etc., it is not easy to achieve a time accuracy of 1 ms due to various limitations such as the accuracy of the built-in clock generator and the effects of communication delays related to synchronization. For example, built-in clock generators in consumer electronics can have errors on the order of 100 ppm due to various factors. This means that even a recording of only 10 seconds cannot guarantee 1 ms time accuracy, an error that cannot be ignored. The problem is further complicated by the addition of error factors based on software architecture and equipment operation. To cope with such problems, professional equipment uses a synchronization signal input to guarantee time accuracy, but this is not a common practice in consumer equipment. Several methods and system architectures proposed in this paper aim to achieve time synchronization between independent data loggers, motion sensors, and different media such as video and audio with errors within 1 ms. In order to record the sampling timing of the system clock and sensors related to the software with an accuracy of less than 1 ms, we explain a method that takes advantage of the fact that the 1-second timing pulse (1-PPS signal) output by the GNSS receiver has an accuracy of about 50 nanoseconds. Furthermore, we propose a method to precisely identify the time of image capture using an optical beacon (called GNSS Clock Beacon (GCB) in this paper) with multiple LEDs driven by the 1-PPS signal. Using this method, we show that it is possible to determine the time of capture from a single image with an accuracy equivalent to the exposure time or less than half of the exposure time.

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Section: Related Workmentioning

confidence: 99%

A mobile recording system featuring high-precision time synchronization

Sone,

Maeda,

Kitani

2023

The Evolving Scholar - BMD 2023, 5th Edition

Self Cite

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Design of Digital Twin Architecture for 3D Audio Representation in AR

Takada,

Nakazato,

Orsholits

et al. 2024

2024 IEEE International Conference on Metaverse Computing, Networking, and Applications (MetaCom)

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A mobile recording system featuring high-precision time synchronization

Sone,

Maeda,

Kitani

2024

The Evolving Scholar - BMD 2023, 5th Edition

View full text Add to dashboard Cite

In mobile environments where recording devices and subjects are in motion, integrating data collected from multiple devices requires precise location and time information. Given that high-precision satellite positioning technology provides centimeter-level accuracy and that movement speeds in mobile environments are around several 10 m/s, the required time accuracy is under 1 millisecond. However, achieving this time accuracy with commonly used devices is not typically feasible. This paper describes a basic architecture to realize time synchronization with less than one millisecond error with an independent recorder using high-precision timing pulses (1-PPS signal) output by a GNSS receiver. Next, we propose a method to precisely identify the image capture time using an optical beacon combining multiple point light sources called GNSS Clock Beacon (GCB). The time of image capture can be determined from GCB images with an accuracy less than or equal to the exposure duration. Finally, we describe an example implementation of a mobile recording system that can be mounted on a motorcycle, which can record time-synchronized data and video with high accuracy using multiple data loggers and video equipment.

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An Ontology for Spatio-Temporal Media Management and an Interactive Application

Cited by 3 publications

References 41 publications

A mobile recording system featuring high-precision time synchronization

A mobile recording system featuring high-precision time synchronization

Design of Digital Twin Architecture for 3D Audio Representation in AR

A mobile recording system featuring high-precision time synchronization

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