An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration Target
In this contribution, we present a simple and intuitive approach for estimating the exterior (geometrical) calibration of a Lidar instrument with respect to a camera as well as their synchronization shifting (temporal calibration) during data acquisition. For the geometrical calibration, the 3D rigi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-07-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/22/15/5576 |
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| author | Lazaros Grammatikopoulos Anastasios Papanagnou Antonios Venianakis Ilias Kalisperakis Christos Stentoumis |
| author_facet | Lazaros Grammatikopoulos Anastasios Papanagnou Antonios Venianakis Ilias Kalisperakis Christos Stentoumis |
| author_sort | Lazaros Grammatikopoulos |
| collection | DOAJ |
| description | In this contribution, we present a simple and intuitive approach for estimating the exterior (geometrical) calibration of a Lidar instrument with respect to a camera as well as their synchronization shifting (temporal calibration) during data acquisition. For the geometrical calibration, the 3D rigid transformation of the camera system was estimated with respect to the Lidar frame on the basis of the establishment of 2D to 3D point correspondences. The 2D points were automatically extracted on images by exploiting an AprilTag fiducial marker, while the detection of the corresponding Lidar points was carried out by estimating the center of a custom-made retroreflective target. Both AprilTag and Lidar reflective targets were attached to a planar board (calibration object) following an easy-to-implement set-up, which yielded high accuracy in the determination of the center of the calibration target. After the geometrical calibration procedure, the temporal calibration was carried out by matching the position of the AprilTag to the corresponding Lidar target (after being projected onto the image frame), during the recording of a steadily moving calibration target. Our calibration framework was given as an open-source software implemented in the ROS platform. We have applied our method to the calibration of a four-camera mobile mapping system (MMS) with respect to an integrated Velodyne Lidar sensor and evaluated it against a state-of-the-art chessboard-based method. Although our method was a single-camera-to-Lidar calibration approach, the consecutive calibration of all four cameras with respect to the Lidar sensor yielded highly accurate results, which were exploited in a multi-camera texturing scheme of city point clouds. |
| first_indexed | 2024-03-09T05:01:16Z |
| format | Article |
| id | doaj.art-92de754ff87c4178a6f48cf4369be7a0 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-09T05:01:16Z |
| publishDate | 2022-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj.art-92de754ff87c4178a6f48cf4369be7a02023-12-03T13:00:18ZengMDPI AGSensors1424-82202022-07-012215557610.3390/s22155576An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration TargetLazaros Grammatikopoulos0Anastasios Papanagnou1Antonios Venianakis2Ilias Kalisperakis3Christos Stentoumis4up2metric P.C., Engineering-Research-Software Development, Michail Mela 21, 11521 Athens, Greeceup2metric P.C., Engineering-Research-Software Development, Michail Mela 21, 11521 Athens, Greeceup2metric P.C., Engineering-Research-Software Development, Michail Mela 21, 11521 Athens, Greeceup2metric P.C., Engineering-Research-Software Development, Michail Mela 21, 11521 Athens, Greeceup2metric P.C., Engineering-Research-Software Development, Michail Mela 21, 11521 Athens, GreeceIn this contribution, we present a simple and intuitive approach for estimating the exterior (geometrical) calibration of a Lidar instrument with respect to a camera as well as their synchronization shifting (temporal calibration) during data acquisition. For the geometrical calibration, the 3D rigid transformation of the camera system was estimated with respect to the Lidar frame on the basis of the establishment of 2D to 3D point correspondences. The 2D points were automatically extracted on images by exploiting an AprilTag fiducial marker, while the detection of the corresponding Lidar points was carried out by estimating the center of a custom-made retroreflective target. Both AprilTag and Lidar reflective targets were attached to a planar board (calibration object) following an easy-to-implement set-up, which yielded high accuracy in the determination of the center of the calibration target. After the geometrical calibration procedure, the temporal calibration was carried out by matching the position of the AprilTag to the corresponding Lidar target (after being projected onto the image frame), during the recording of a steadily moving calibration target. Our calibration framework was given as an open-source software implemented in the ROS platform. We have applied our method to the calibration of a four-camera mobile mapping system (MMS) with respect to an integrated Velodyne Lidar sensor and evaluated it against a state-of-the-art chessboard-based method. Although our method was a single-camera-to-Lidar calibration approach, the consecutive calibration of all four cameras with respect to the Lidar sensor yielded highly accurate results, which were exploited in a multi-camera texturing scheme of city point clouds.https://www.mdpi.com/1424-8220/22/15/5576extrinsic calibrationLidarcameracalibration targettemporal calibration |
| spellingShingle | Lazaros Grammatikopoulos Anastasios Papanagnou Antonios Venianakis Ilias Kalisperakis Christos Stentoumis An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration Target Sensors extrinsic calibration Lidar camera calibration target temporal calibration |
| title | An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration Target |
| title_full | An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration Target |
| title_fullStr | An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration Target |
| title_full_unstemmed | An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration Target |
| title_short | An Effective Camera-to-Lidar Spatiotemporal Calibration Based on a Simple Calibration Target |
| title_sort | effective camera to lidar spatiotemporal calibration based on a simple calibration target |
| topic | extrinsic calibration Lidar camera calibration target temporal calibration |
| url | https://www.mdpi.com/1424-8220/22/15/5576 |
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