Glacier Calving Front Segmentation Using Attention U-Net

• Main Authors: Holzmann, Michael, Davari, Amirabbas, Seehaus, Thorsten, Braun, Matthias, Maier, Andreas, Christlein, Vincent
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: arXiv 2021
• Subjects: Machine Learning cs.LG; Computer Vision and Pattern Recognition cs.CV; FOS Computer and information sciences; Tidewater
• Online Access: https://dx.doi.org/10.48550/arxiv.2101.03247; https://arxiv.org/abs/2101.03247

An essential climate variable to determine the tidewater glacier status is the location of the calving front position and the separation of seasonal variability from long-term trends. Previous studies have proposed deep learning-based methods to semi-automatically delineate the calving fronts of tidewater glaciers. They used U-Net to segment the ice and non-ice regions and extracted the calving fronts in a post-processing step. In this work, we show a method to segment the glacier calving fronts from SAR images in an end-to-end fashion using Attention U-Net. The main objective is to investigate the attention mechanism in this application. Adding attention modules to the state-of-the-art U-Net network lets us analyze the learning process by extracting its attention maps. We use these maps as a tool to search for proper hyperparameters and loss functions in order to generate higher qualitative results. Our proposed attention U-Net performs comparably to the standard U-Net while providing additional insight into those regions on which the network learned to focus more. In the best case, the attention U-Net achieves a 1.5% better Dice score compared to the canonical U-Net with a glacier front line prediction certainty of up to 237.12 meters.