In plain words: A network learns to tell that two altered copies of one galaxy photo match, picking up useful features without labels, then is tuned to estimate a galaxy's distance from its image. It matched a fully labeled system's accuracy with 2 to 4 times fewer labels.
Abstract · Estimating Galactic Distances From Images Using Self-supervised Representation Learning
We use a contrastive self-supervised learning framework to estimate distances to galaxies from their photometric images. We incorporate data augmentations from computer vision as well as an application-specific augmentation accounting for galactic dust. We find that the resulting visual representations of galaxy images are semantically useful and allow for fast similarity searches, and can be successfully fine-tuned for the task of redshift estimation. We show that (1) pretraining on a large corpus of unlabeled data followed by fine-tuning on some labels can attain the accuracy of a fully-supervised model which requires 2-4x more labeled data, and (2) that by fine-tuning our self-supervised representations using all available data labels in the Main Galaxy Sample of the Sloan Digital Sky Survey (SDSS), we outperform the state-of-the-art supervised learning method.
Md Abul Hayat, Peter Harrington, George Stein, Zarija Lukić, Mustafa Mustafa
arXiv:2101.04293 · astro-ph.IM, astro-ph.CO, cs.AI · submitted Jan 12, 2021
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