Clock-based time synchronization for an event-based camera dataset acquisition platform

Osadčuks, Vitālijs; Pudžs, Mihails; Zujevs, Andrejs; Pecka, A.; Ardavs, Arturs

doi:10.1109/icra40945.2020.9197303

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…The sunlight interferes with the light emitted by the sensor thus changing the output values. Hall effect sensor had shown minimum deviation from actual value because sensors based on nonoptical principle are very less affected by changing environment [18,19]. Sreenivasulu and Raghavendra [14] found similar results for Hall effect sensor that can work in robust conditions for rotational speed measurement.…”

Section: Resultsmentioning

confidence: 75%

Development and Performance Assessment of Real-time Rotational Speed Measurement System for Agricultural Application

Mahore

Kumar²,

Kushwaha³

et al. 2023

IJPSS

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Rotational speed is one of the most important parameters in the performance of any system. It becomes more vital when the rotational speed measurement is required on real-time basis. Measurement of rotational speed has a crucial role in automation of agricultural machineries for various purposes. The existing real-time speed measurement systems are susceptible to the varying working environment. Therefore, it was necessary to study the performance of available sensor. In this study four different sensors (inductive proximity, Infrared (IR), Hall effect and optical proximity sensors) were tested in three different working environments (indoor, outdoor and outdoor dusty condition) for two different spacings (2 and 5 mm) between sensors and target. A laboratory setup was developed to test the performance of the sensors in terms of percentage deviation in rotational speeds measurement compared to actual values. The values were recorded in Secure Digital (SD) card and analysed using full factorial design. The means of the different levels were compared using Tukey’s (b) method. There was significant difference in sensor response for different conditions. The percentage of deviation in speed for Hall effect, inductive proximity, IR and optical proximity sensors varied from 0.55 to 1.03, 1.20 to 32.29, 21.37 to 100.00 and 35.18 to 99.98%, respectively. The study concluded that the Hall effect sensor was more suitable for rotational speed measurement than the other sensors without being affected by working environment.

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Section: Resultsmentioning

confidence: 75%

Development and Performance Assessment of Real-time Rotational Speed Measurement System for Agricultural Application

Mahore

Kumar²,

Kushwaha³

et al. 2023

IJPSS

View full text Add to dashboard Cite

show abstract

“…Robotic systems often time stamp sensors on different clocks and then translate the stamp from one clock to the other by estimating the clock offset and skew. The time offset estimation can either be based on comparing the same time stamps on two clocks (Eidson et al, 2002;Sommer et al, 2017;Osadcuks et al, 2020) or based on the correlation of sensor motions, such as a camera and IMU movement (Furgale et al, 2012;Li and Mourikis, 2014;Kelly and Sukhatme, 2014;Qin and Shen, 2018). More specifically, (Skog and Handel, 2011) propose a GNSS-inertial fusion algorithm that self-calibrates the timing offset.…”

Section: Related Workmentioning

confidence: 99%

Under the Sand: Navigation and Localization of a Micro Aerial Vehicle for Landmine Detection with Ground-Penetrating Synthetic Aperture Radar

Bähnemann¹,

Lawrance²,

Streichenberg³

et al. 2022

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Ground-penetrating radar mounted on a micro aerial vehicle (MAV) is a promising tool to assist humanitarian landmine clearance. However, the quality of synthetic aperture radar images depends on accurate and precise motion estimation of the radar antennas as well as generating informative viewpoints with the MAV. This paper presents a complete and automatic airborne ground-penetrating synthetic aperture radar (GPSAR) system. The system consists of a spatially calibrated and temporally synchronized industrial grade sensor suite that enables navigation above ground level, radar imaging, and optical imaging. A custom mission planning framework allows generation and automatic execution of stripmap and circular GPSAR trajectories controlled above ground level as well as aerial imaging survey flights. A factor graph based state estimator fuses measurements from dual receiver real-time kinematic (RTK) global navigation satellite system (GNSS) and an inertial measurement unit (IMU) to obtain precise, high-rate platform positions and orientations. Ground truth experiments showed sensor timing as accurate as 0.8 µs and as precise as 0.1 µs with localization rates of 1 kHz. The dual position factor formulation improves online localization accuracy up to 40 % and batch localization accuracy up to 59 % compared to a single position factor with uncertain heading initialization. Our field trials validated a localization accuracy and precision that enables coherent radar measurement addition and detection of radar targets buried in sand. This validates the potential as an aerial landmine detection system.

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“…Robotic systems often time stamp sensors on different clocks and then translate the stamp from one clock to the other by estimating the clock offset and skew. The time offset estimation can either be based on comparing the same time stamps on two clocks (Eidson et al, 2002;Sommer et al, 2017;Osadcuks et al, 2020) or based on the correlation of sensor motions, such as camera and IMU movement (Furgale et al, 2012;Qin and Shen, 2018). More specific, (Skog and Handel, 2011) identify time delay between IMU and GNSS as a significant error source in motion estimation and propose a fusion algorithm that corrects the timing offset.…”

Section: Related Workmentioning

confidence: 99%

Under the Sand: Navigation and Localization of a Micro Aerial Vehicle for Landmine Detection with Ground Penetrating Synthetic Aperture Radar

Bähnemann,

Lawrance,

Streichenberg

et al. 2021

Preprint

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Ground penetrating radar mounted on a small unmanned aerial vehicle (UAV) is a promising tool to assist humanitarian landmine clearance. However, the quality of synthetic aperture radar images depends on accurate and precise motion estimation of the radar antennas as well as generating informative viewpoints with the UAV. This paper presents a complete and automatic airborne ground-penetrating synthetic aperture radar (GPSAR) system. The system consists of a spatially calibrated and temporally synchronized industrial grade sensor suite that enables navigation above ground level, radar imaging, and optical imaging. A custom mission planning framework allows generation and automatic execution of stripmap and circular GPSAR trajectories controlled above ground level as well as aerial imaging survey flights. A factor graph based state estimator fuses measurements from dual receiver real-time kinematic (RTK) global navigation satellite system (GNSS) and an inertial measurement unit (IMU) to obtain precise, high rate platform positions and orientations. Ground truth experiments showed sensor timing as accurate as 0.8 µs and as precise as 0.1 µs with localization rates of 1 kHz. The dual position factor formulation improves online localization accuracy up to 40 % and batch localization accuracy up to 59 % compared to a single position factor with uncertain heading initialization. Our field trials validated a localization accuracy and precision that enables coherent radar measurement addition and detection of radar targets buried in sand. This validates the potential as an aerial landmine detection system.

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Clock-based time synchronization for an event-based camera dataset acquisition platform

Cited by 7 publications

References 14 publications

Development and Performance Assessment of Real-time Rotational Speed Measurement System for Agricultural Application

Development and Performance Assessment of Real-time Rotational Speed Measurement System for Agricultural Application

Under the Sand: Navigation and Localization of a Micro Aerial Vehicle for Landmine Detection with Ground-Penetrating Synthetic Aperture Radar

Under the Sand: Navigation and Localization of a Micro Aerial Vehicle for Landmine Detection with Ground Penetrating Synthetic Aperture Radar

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