Core Concepts
A generalized few-shot segmentation-based framework, named SegLand, is proposed to efficiently update novel land cover classes in high-resolution remote sensing imagery with limited labeled data.
Abstract
The paper presents a framework called SegLand to address the challenge of discovering novel land cover classes in high-resolution remote sensing imagery. The framework consists of three main components:
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Data Pre-processing:
- Analyzes and augments the base training set and few-shot support sets of novel classes to address class imbalance and enhance the representation of novel classes.
- Introduces a novel "NovelCutMix" augmentation strategy to generate new training samples that exclusively represent novel classes.
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Hybrid Segmentation Structure:
- Trains multiple base learner models (e.g., HRNet, ResNeXt, EfficientNet, UNetFormer) on the base training set to achieve high accuracy on recognizing base land cover classes.
- Adopts a modified Projection onto Orthogonal Prototypes (POP) network to simultaneously learn representations for both base and novel classes, ensuring non-interference between the two stages.
- Explores different backbone and decoder architectures (e.g., Swin Transformer, UperNetPlus) to optimize the feature extractor for the POP network.
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Ultimate Fusion:
- Combines the semantic segmentation results of the base learners and the POP network to produce the final land cover map.
- Uses the stable base class results from the base learners to constrain and optimize the POP network's predictions on the base classes.
The proposed SegLand framework demonstrates superior performance in the OpenEarthMap Land Cover Mapping Few-Shot Challenge, outperforming other competing methods. It showcases the potential of generalized few-shot segmentation techniques to facilitate efficient updates of high-resolution land cover maps with limited labeled data.
Stats
The base training set contains 258 tiles of 512x512 pixels.
The few-shot support set in phase 1 contains 20 tiles with 4 novel classes, each with 5 shots.
The few-shot support set in phase 2 contains 4 novel classes, each with 5 shots.
Quotes
"With higher spatial resolution, richer land objects that were previously unseen can now be observed. However, discovering novel classes in HR land-cover mapping is still a non-trivial task hindered by the various scales of land objects and also the scarcity of training labels over a wide-span geographic area."
"To address these challenges, we propose a GFSS-based land-cover mapping framework, named SegLand, to discover the novel land-cover classes that appear on the base land-cover maps."