ABSTRACT Accurate extraction of large-area urban built-up areas is of significant importance for urban development and map updating. Traditional methods relying on remote sensing imagery and deep learning exhibit low data utilization during the model training phase and significant discrepancies between extraction accuracy in application scenarios and during training, posing challenges in practical applications. In response to these issues, this paper proposes an urban built-up area extraction method based on deep learning semantic segmentation technology and large-size remote sensing imagery. This method, grounded in the sliding window theory, introduces the Overlapping Cutting and Joining (OCJ) approach. Within the OCJ method, this paper develops the Overlapping Cutting (OC) module to increase the quantity and richness of training samples. In application scenarios, the OC and Overlapping Joining (OJ) modules are utilized to circumvent large-size cross-sampling, thereby preserving original image information and enhancing segmentation accuracy. Additionally, to eliminate stitching seams and optimize detailed segmentation effects, this paper proposes the HCBM-DenseCRF method, which employs DenseCRF to eliminate stitching seams while utilizing the Hard Constraint Buffer Mechanism (HCBM) to protect complex built-up area foreground extraction results from destruction, achieving high-precision urban built-up area extraction. This paper takes the Xception-PSPNet deep learning semantic segmentation model as the base model instance and compares it with four widely used models and three ablation models, including the initial Xception-PSPNet model. OCJ-HCBM-DenseCRF achieved superior results compared to other methods across smaller, medium, and larger remote sensing image instances, particularly leading other models by 1.1%-47.3% on larger-size imagery, with a precision decrement of only 1%-2% across the three sizes. This indicates the high application value of the proposed method in the extraction of large-size imagery.
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