Monitoring Earth activity using data collected from multiple satellite imaging platforms in a unified way is a significant challenge, especially with large variability in image resolution, spectral bands, and revisit rates. Further, the availability of sensor data varies across time as new platforms are launched. In this work, we introduce an adaptable framework and network architecture capable of predicting on subsets of the available platforms, bands, or temporal ranges it was trained on. Our system, called WATCH, is highly general and can be applied to a variety of geospatial tasks. In this work, we analyze the performance of WATCH using the recent IARPA SMART public dataset and metrics. We focus primarily on the problem of broad area search for heavy construction sites. Experiments validate the robustness of WATCH during inference to limited sensor availability, as well the the ability to alter inference-time spatial or temporal sampling. WATCH is open source and available for use on this or other remote sensing problems. Code and model weights are available at: https://gitlab.kitware.com/computer-vision/geowatch

Self-supervised learning aims to learn image feature representations without the usage of manually annotated lbabels. It is often used as a precursor step to obtain useful initial network weights which contribute to faster convergence and superior performance of downstream tasks. While self-supervision allows one to reduce the domain gap between supervised and unsupervised learning without the usage of labels, the self-supervised objective still requires a strong inductive bias to downstream tasks for effective transfer learning. In this work, we present our material and texture based self-supervision method named MATTER (MATerial and TExture Representation Learning), which is inspired by classical material and texture methods. Material and texture can effectively describe any surface, including its tactile properties, color, and specularity. By extension, effective representation of material and texture can describe other semantic classes strongly associated with said material and texture. MATTER leverages multitemporal, spatially aligned remote sensing imagery over unchanged regions to learn invariance to illumination and viewing angle as a mechanism to achieve consistency of material and texture representation. We show that our self-supervision pre-training method allows for up to 24.22% and 6.33% performance increase in unsupervised and finetuned setups, and up to 76% faster convergence on change detection, land cover classification, and semantic segmentation tasks. Code and dataset: https://github.com/periakiva/MATTER.

This paper describes an open-source dataset framework de-signed for machine learning remote sensing datasets called Finch after the finches Charles Darwin studied while devel-oping the theory of evolution. The Finch Framework enables datasets to be created from annotations-to-images and to ef-ficiently modify an existing dataset. Commonly, datasets are released once and never updated to become more challenging or to correct mistakes. Our proposed framework encourages datasets to evolve over time and provides a version control system for consistent comparisons between experiments. We utilize other open-source tools and unique attributes of re-mote sensing data to characterize entire datasets with a few lightweight configuration files. Generated datasets are ac-companied with a dataset manifest file, providing a consistent and powerful format for referencing all data. The standard dataset representation reduces the time required to integrate datasets into machine learning pipelines.

The sky exhibits a unique spatial polarization pattern by scattering the unpolarized sun light. Just like insects use this unique angular pattern to navigate, we use it to map pixels to directions on the sky. That is, we show that the unique polarization pattern encoded in the polarimetric appearance of an object captured under the sky can be decoded to reveal the surface normal at each pixel. We derive a polarimetric reflection model of a diffuse plus mirror surface lit by the sun and a clear sky. This model is used to recover the per-pixel surface normal of an object from a single polarimetric image or from multiple polarimetric images captured under the sky at different times of the day. We experimentally evaluate the accuracy of our shape-from-sky method on a number of real objects of different surface compositions. The results clearly show that this passive approach to fine-geometry recovery that fully leverages the unique illumination made by nature is a viable option for 3D sensing. With the advent of quad-Bayer polarization chips, we believe the implications of our method span a wide range of domains.

Accurate flood detection in near real time via high resolution, high latency satellite imagery is essential to prevent loss of lives by providing quick and actionable information. Instruments and sensors useful for flood detection are only available in low resolution, low latency satellites with region re-visit periods of up to 16 days, making flood alerting systems that use such satellites unreliable. This work presents H2O-Network, a self-supervised deep learning method to segment floods from satellites and aerial imagery by bridging domain gap between low and high latency satellite and coarse-to-fine label refinement. H2O-Net learns to synthesize signals highly correlative with water presence as a domain adaptation step for semantic segmentation in high resolution satellite imagery. Our work also proposes a self-supervision mechanism, which does not require any hand annotation, used during training to generate high quality ground truth data. We demonstrate that H2O-Net outperforms the state-of-the-art semantic segmentation methods on satellite imagery by 10% and 12% pixel accuracy and mIoU respectively for the task of flood segmentation. We emphasize the generalizability of our model by transferring model weights trained on satellite imagery to drone imagery, a highly different sensor and domain.

Moving cameras provide multiple intensity measurements per pixel, yet often semantic segmentation, material recognition, and object recognition do not utilize this information. With basic alignment over several frames of a moving camera sequence, a distribution of intensities over multiple angles is obtained. It is well known from prior work that luminance histograms and the statistics of natural images provide a strong material recognition cue. We utilize per-pixel angular luminance distributions as a key feature in discriminating the material of the surface. The angle-space sampling in a multiview satellite image sequence is an unstructured sampling of the underlying reflectance function of the material. For real-world materials there is significant intra-class variation that can be managed by building a angular luminance network (AngLNet). This network combines angular reflectance cues from multiple images with spatial cues as input to fully convolutional networks for material segmentation. We demonstrate the increased performance of AngLNet over prior state-of-the-art in material segmentation from satellite imagery.