Assessment and Improvement of Distance Measurement Accuracy for Time-of-Flight Cameras


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Date

2022

Publication Type

Journal Article

ETH Bibliography

yes

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Data

Abstract

Time-of-flight depth cameras are interesting sensors for contact-less 3-D metrology because they combine mechanical robustness with independence of ambient lighting conditions. Their actual performance depends on many factors and is hard to predict from data sheets. In this study, we investigate the deviations of the distance measurements of a high-end phase-based depth camera. We focus on the impact of: 1) self-warming and external temperature; 2) on range noise as a function of distance and acquisition time; and 3) on distance-dependent biases. We present the dedicated experimental setups comprising a climate chamber, a calibration bench with a reference interferometer, and a laser tracker that provides controlled conditions and ground-truth data. These setups allow investigating the absolute accuracy and mitigating repeatable distance biases by adapting the measurement model based on experimental data. For demonstration, we apply the investigation to two state-of- the-art industrial depth cameras of the same brand and type (Helios Lucid), showing significantly different response to external temperature but similar distance-dependent biases. We adapt the measurement model of one of the cameras for distance-dependent inter-pixel biases and demonstrate that the resulting parameters reduce also the distance biases of the other camera by about 80% to less than 1 mm at ranges of up to 1 m. This indicates the potential for batch error compensation. This article contributes to better understanding distance deviations of depth cameras and to improving the accuracy of such cameras.

Publication status

published

Editor

Book title

Volume

71

Pages / Article No.

1003511

Publisher

IEEE

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Accuracy assessment; depth camera; distance errors; error compensation; metrology; time-of-flight (ToF)

Organisational unit

03964 - Wieser, Andreas / Wieser, Andreas check_circle
02284 - NFS Digitale Fabrikation / NCCR Digital Fabrication

Notes

Funding

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