Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle Imageries

Recently, analysis and decision-making based on spatiotemporal unmanned aerial vehicle (UAV) high-resolution imagery are gaining significant attention in smart agriculture. Constructing a spatiotemporal dataset requires multiple UAV image mosaics taken at different times. Because the weather or a UA...

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Main Authors: Hyeonseok Lee, Semo Kim, Dohun Lim, Seoung-Hun Bae, Lae-Hyong Kang, Sungchan Kim
Format: Article
Language:English
Published: MDPI AG 2023-02-01
Series:Drones
Subjects:
Online Access:https://www.mdpi.com/2504-446X/7/2/131
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author Hyeonseok Lee
Semo Kim
Dohun Lim
Seoung-Hun Bae
Lae-Hyong Kang
Sungchan Kim
author_facet Hyeonseok Lee
Semo Kim
Dohun Lim
Seoung-Hun Bae
Lae-Hyong Kang
Sungchan Kim
author_sort Hyeonseok Lee
collection DOAJ
description Recently, analysis and decision-making based on spatiotemporal unmanned aerial vehicle (UAV) high-resolution imagery are gaining significant attention in smart agriculture. Constructing a spatiotemporal dataset requires multiple UAV image mosaics taken at different times. Because the weather or a UAV flight trajectory is subject to change when the images are taken, the mosaics are typically unaligned. This paper proposes a two-step approach, composed of global and local alignments, for spatiotemporal alignment of two wide-area UAV mosaics of high resolution. The first step, global alignment, finds a projection matrix that initially maps keypoints in the source mosaic onto matched counterparts in the target mosaic. The next step, local alignment, refines the result of the global alignment. The proposed method splits input mosaics into patches and applies individual transformations to each patch to enhance the remaining local misalignments at patch level. Such independent local alignments may result in new artifacts at patch boundaries. The proposed method uses a simple yet effective technique to suppress those artifacts without harming the benefit of the local alignment. Extensive experiments validate the proposed method by using several datasets for highland fields and plains in South Korea. Compared with a recent work, the proposed method improves the accuracy of alignment by up to 13.21% over the datasets.
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spelling doaj.art-481e58c2d3a245919474df763b9f684c2023-11-16T20:07:03ZengMDPI AGDrones2504-446X2023-02-017213110.3390/drones7020131Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle ImageriesHyeonseok Lee0Semo Kim1Dohun Lim2Seoung-Hun Bae3Lae-Hyong Kang4Sungchan Kim5Department of Computer Science and Artificial Intelligence, Jeonbuk National University, Jeonju 54896, Republic of KoreaDepartment of Mechatronics Engineering, Jeonbuk National University, Jeonju 54896, Republic of KoreaDepartment of Computer Science and Artificial Intelligence, Jeonbuk National University, Jeonju 54896, Republic of KoreaSpatial Information Research Institute, Korea Land and Geospatial Informatix Corporation, Jeonju 54870, Republic of KoreaDepartment of Mechatronics Engineering, Jeonbuk National University, Jeonju 54896, Republic of KoreaDepartment of Computer Science and Artificial Intelligence, Jeonbuk National University, Jeonju 54896, Republic of KoreaRecently, analysis and decision-making based on spatiotemporal unmanned aerial vehicle (UAV) high-resolution imagery are gaining significant attention in smart agriculture. Constructing a spatiotemporal dataset requires multiple UAV image mosaics taken at different times. Because the weather or a UAV flight trajectory is subject to change when the images are taken, the mosaics are typically unaligned. This paper proposes a two-step approach, composed of global and local alignments, for spatiotemporal alignment of two wide-area UAV mosaics of high resolution. The first step, global alignment, finds a projection matrix that initially maps keypoints in the source mosaic onto matched counterparts in the target mosaic. The next step, local alignment, refines the result of the global alignment. The proposed method splits input mosaics into patches and applies individual transformations to each patch to enhance the remaining local misalignments at patch level. Such independent local alignments may result in new artifacts at patch boundaries. The proposed method uses a simple yet effective technique to suppress those artifacts without harming the benefit of the local alignment. Extensive experiments validate the proposed method by using several datasets for highland fields and plains in South Korea. Compared with a recent work, the proposed method improves the accuracy of alignment by up to 13.21% over the datasets.https://www.mdpi.com/2504-446X/7/2/131unmanned aerial vehicle (UAV)spatiotemporal imageimage alignmentsmart agriculture
spellingShingle Hyeonseok Lee
Semo Kim
Dohun Lim
Seoung-Hun Bae
Lae-Hyong Kang
Sungchan Kim
Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle Imageries
Drones
unmanned aerial vehicle (UAV)
spatiotemporal image
image alignment
smart agriculture
title Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle Imageries
title_full Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle Imageries
title_fullStr Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle Imageries
title_full_unstemmed Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle Imageries
title_short Two-Step Approach toward Alignment of Spatiotemporal Wide-Area Unmanned Aerial Vehicle Imageries
title_sort two step approach toward alignment of spatiotemporal wide area unmanned aerial vehicle imageries
topic unmanned aerial vehicle (UAV)
spatiotemporal image
image alignment
smart agriculture
url https://www.mdpi.com/2504-446X/7/2/131
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