Filtering Specialized Change in a Few-Shot Setting

Abstract

The aim of change detection in remote sensing usually is not to find all differences between the observations, but rather only specific types of change, such as urban development, deforestation, or even more specialized categories like roadwork. However, often there are no large public datasets available for very fine-grained tasks, and to collect the amount of training data needed for most supervised learning methods is very costly and often prohibitive. For this reason, we formulate the problem of few-shot filtering, where we are provided with a relatively large change detection dataset and, at test time, a few instances of one particular change type that we try to "filter out" of the learned changes. For example, we might train on data of general urban change, and, given some samples of building construction, aim to only predict instances of these on the test set, all without any explicit labels for buildings in the training data. We further investigate a fine-tuning approach to this problem and assess its performance on a public dataset that we adapt to be used in this novel setting. Code will be available at https://gitlab.lrz.de/ai4eo/cd/-/blob/main/fewShotFilteringCd.

A national-scale assessment of land subsidence in China’s major cities

“…In coastal regions, land subsidence can amplify the risk of inundation caused by rising sea levels (47). We therefore also projected the proportion of coastal lands that will have a relative elevation lower than sea level under the combined effect of sea-level rise and land subsidence by 2120 (22).…”