Sentinel 1 and 2: Searching for Physical Image Content

Kurzfassung

ESA’s upcoming Sentinel-1 and Sentinel-2 missions open new perspectives for the application-oriented use of SAR and/or optical multispectral images. We expect short and regular revisit times as well as easily available and well documented products with attractive features such as cross-polarized SAR images and optical images delivered, for instance, as spectral reflectance data. Thus, users do not have to live any longer with simple digital units or detector counts; instead, the data provided as Sentinel products can be understood as samples of calibrated and validated physical quantities. As a consequence, users can concentrate immediately on the physics and quantitative details of the observable phenomena. This also affects content-based image retrieval, where a user searches for images containing phenomena being similar to given examples. While retrieval systems based on visible image data can only exploit characteristic shapes or patterns, the use of Sentinel data will address the determination of real physical relationships. In particular, this allows a physics-based analysis of image time series data, where one analyzes spatio-temporal phenomena. This physics-based approach will allow us to employ content-based image retrieval as an attractive tool for the analysis of SAR and optical images.