Subpixel Automatic Detection of GCP Coordinates in Time-Lapse Images Using a Deep Learning Keypoint Network

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

Abstract

In this study, we present an approach to exploit the keypoint R-CNN network structure for automated detection of ground control points (GCPs) in images acquired by optical sensors. Our deep learning methodology employs fine-tuning on three distinct datasets, thereby enabling the specific addressing of inherent variations in GCP types, including shape, size, and colour. Our approach uses an end-to-end artificial intelligence (AI)-based approach that does not require any post-processing of the data or the use of specific GCPs. Performance metrics are evaluated to compare the AI results with manually labelled data, coordinates obtained by an ellipse fitting algorithm for circular targets, and a semi-automatic optical flow algorithm for arbitrary targets (e.g. crosses). The study highlights the importance of a dataset-specific fine-tuning and data augmentation strategy to enhance the model's accuracy in locating GCPs. The results demonstrate the effectiveness of the R-CNN keypoint approach in successfully identifying GCPs with sub-pixel accuracy compared to manual labelling in all datasets. Our AI-based approach outperformed semi-automatic methods based on computer vision algorithms, identifying GCPs in images taken under adverse conditions and in cases where GCPs were partially obscured. Furthermore, the results demonstrate robust performance in a transferability test, i.e., identifying GCPs in different images obtained at different locations and with different cameras than those used for training.

Details

Original languageEnglish
Article number5601714
Number of pages14
JournalIEEE Transactions on Geoscience and Remote Sensing
Volume63
Early online date11 Dec 2024
Publication statusPublished - 2025
Peer-reviewedYes

External IDs

ORCID /0000-0003-2169-8762/work/180881679
Mendeley c03b792b-42ff-3359-9f4f-4c9764ba13be

Keywords

Keywords

  • automatic detection, ground control point, mask R-CNN keypoint, photogrammetry, ResNet50, mask R-convolutional neural network (CNN) keypoint, ground control point (GCP), Automatic detection