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Figure 1: Presto learns from structurally-masked remote sensing pixel-timeseries . We construct a
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multi-sensor remote sensing pixel-timeseries, and randomly select one of the four masking strategies
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described in Section 3.3. The encoder-decoder model is trained to reconstruct the original timeseries.
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At fine-tuning time, we discard the decoder and only use the encoder’s output. The downstream task
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may have incomplete inputs (missing timesteps or sensors) since the encoder is specifically trained on
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such inputs. Presto receives both static-in-time and dynamic-in-time inputs and the location metadata
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of each pixel timeseries.
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many remote sensing datasets, which are points or irregularly shaped polygons (Rao et al., 2020;
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Batjes et al., 2017), requiring additional methods to handle these labels (Wang et al., 2020a).
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We introduce the Pretrained Remote Sensing Transf ormer (Presto), a lightweight model designed to
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ingest pixel-timeseries inputs from a variety of Earth observation sensors and data products. Presto
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operates on individual pixels, using the temporal and multimodal structure of the data instead of the
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image structure. To learn powerful representations of remote sensing data that can be adapted to a
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wide range of tasks, Presto leverages a self-supervised masked autoencoding approach, reconstructing
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unobserved timepoints and sensory modalities. This allows Presto to be robust to missing data and to
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flexibly accommodate diverse input formats. We find Presto excels even in image-based tasks where
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the temporal dimension is completely absent.
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Presto addresses the following requirements, which are critical to the useful deployment of pre-trained
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models in the remote sensing context:
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•Computational efficiency : When deployed, models built for remote sensing data are typically used
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to make contiguous geospatial predictions over millions (or billions) of samples to form a predicted
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map. The computational performance of models is therefore one of the primary considerations at
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deployment time. Van Tricht (2021), Hengl et al. (2017) and Robinson et al. (2019) are all global-
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or large- scale map making efforts that prioritized efficiency over accuracy when deploying remote
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sensing models at scale. Presto is competitive with ViT or ResNet based models, despite having up
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to1000×fewer trainable parameters and requiring orders of magnitude fewer FLOPs at inference
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time.
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•Ability to process inputs of varying shapes : Different downstream tasks may require very
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different remote sensing inputs. For example, for crop mapping and yield estimation, Sainte
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Fare Garnot et al. (2020) and You et al. (2017) discarded all spatial information in the inputs in
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favor of emphasizing temporal patterns. We test Presto on a wide range of downstream inputs (for
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example, with spatial information present or absent, and with single or multiple timesteps of data),
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and find it is competitive with models designed specifically for those inputs.
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•Ability to process a range of remote sensing datasets : For fuel moisture estimation, Rao et al.
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(2020) found that the inclusion of derived products in addition to raw inputs significantly improved
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performance. Presto can ingest a range of static-in-time and dynamic-in-time raw input data as well
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as derived product inputs widely used in Earth observation (such as NDVI (Rouse et al., 1974)).
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•Ability to handle missing data : The coverage of remote sensing products is often spatially and
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temporally incomplete. For example, certain regions experience very high ( >90%) cloud coverage,
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reducing the utility of optical measurements such as Sentinel-2 imagery (Sudmanns et al., 2019).
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Because Presto ingests a variety of remote sensing inputs, it can leverage alternative data sources if
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2
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one is missing (for instance, relying on Sentinel-1, which sees through clouds, if Sentinel-2 images
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are cloudy).
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Our results support the surprising conclusion that a pixel-based approach can in some cases match or
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outperform sophisticated computer vision-based approaches. We hypothesize that this is possible
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because (i) Presto learns from many semantically dense data sources, allowing it to extract informative
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patterns from pixel-timeseries, and (ii) many remote sensing tasks require significantly smaller
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receptive fields than those provided by computer vision-based models. Brown et al. (2022) leveraged
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such properties to train a model 100×smaller than standard models while achieving state-of-the-art
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land-cover segmentation results.
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2 Related Work
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Architectures for Remote Sensing When processing remote sensing timeseries, transformers have
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been extensively investigated either as unmodified architectures (Rußwurm and Körner, 2020) or
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as architectures designed for specific tasks (Sainte Fare Garnot et al., 2020; Tarasiou et al., 2023).
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Recurrent networks have also been investigated (Kerner et al., 2020; Rußwurm and Körner, 2020).
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When treating remote sensing data as single or few (up to 3) timestep images, architectures from
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computer vision are commonly used, ranging from ResNets (Manas et al., 2021; Ayush et al., 2021;
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Rußwurm et al., 2020) to Vision Transformers (Cong et al., 2022; Reed et al., 2022; Fuller et al.,
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2023).
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Self-supervised learning for Remote Sensing While contrastive learning has been investigated for
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remote sensing (Manas et al., 2021), recent self-supervised learning research has focused on masked
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autoencoders (Yuan et al., 2022; Cong et al., 2022; Reed et al., 2022; Fuller et al., 2023). However,
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these approaches (i) focus on learning from raw satellite data products (ignoring derived products such
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as elevation) and typically only ingest data from a single sensor (the exception being the CROMA
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model of Fuller et al. (2023), which ingests both Sentinel-1 and Sentinel-2 data), (ii) ingest very
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few or no timesteps (Reed et al. (2022) and Fuller et al. (2023) ingest only one timestep while Cong
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et al. (2022) ingest up to three timesteps), (iii) expect data in a certain size (for instance, ViT based
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models require spatial dimensions to be present), so that missing data is not handled natively, and (iv)
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generally yield larger models ranging from 2.5 million parameters (Yuan and Lin, 2020) to over 300
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million parameters for ViT-based methods, making their deployment in compute-constrained settings
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challenging.
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3 Method
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We aim to learn a model, f, which can learn useful representations in a self-supervised manner given
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unlabelled remote sensing pixel-timeseries data while meeting the usability requirements outlined
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in Section 1. This model can then be applied to a wide variety of downstream remote sensing tasks.
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These downstream tasks may contain input data from a range of sensors with differing numbers of
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timesteps.
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Our approach is based on the masked autoencoding framework (He et al., 2022), in which the network
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architecture includes both an encoder ( f) and a decoder ( g). During pre-training, part of the input is
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masked out and the encoder embeds the remaining (non-masked) part of the input. The decoder aims
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to reconstruct the masked-out part of the input, given the encoder’s output. At fine-tuning time, we
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discard gand only use f(either as a feature extractor or a fine-tuneable model) for downstream tasks.
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In the sections below, we discuss how Presto customizes this general framework for multi-sensor
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remote sensing timeseries data. An overview of the Presto pre-training methodology is shown in
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Figure 1, and full pre-training details are in Section A.1.
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3.1 Pre-training Data
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Self-supervised models for remote sensing must generalize to a wide range of geographies and
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tasks (Lacoste et al., 2023). We therefore aimed to collect a globally representative pre-training
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dataset. We followed the sampling strategy of Brown et al. (2022) to construct a dataset of 21.5M
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pixel samples, each with a resolution of 10m per pixel. Appendix A.1.1 describes the pre-training
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dataset construction process in detail. Presto was trained on pixel-timeseries of 12-month contiguous
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3
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Figure 2: Presto learns to reconstruct channels that are completely masked in a spatially
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cohesive manner . In this experiment, we masked only the Sentinel-2 RGB channels; Presto was able
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to reconstruct these channels even when they were absent from the input. The reconstructions are
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spatially consistent even though Presto only receives single pixel inputs.
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intervals, sampled from a 2-year period from the beginning of 2020 until the end of 2021, with
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each month represented by one timestep (similar to the approach adopted by Tseng et al. (2021)).
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Derived data products that result from the analysis of lower level data (e.g., Parkinson et al. (2006))
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