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We study the impact of catastrophic errors occurring in the photometric redshifts of galaxies on cosmological parameter estimates with cosmic shear tomography. We consider a fiducial survey with 9-filter set and perform photo-z measurement…

Astrophysics · Physics 2014-11-18 L. Sun , Z. -H. Fan , C. Tao , J. -P. Kneib , S. Jouvel , A. Tilquin

In this paper, we introduce a novel data augmentation technique that combines the advantages of style augmentation and random erasing by selectively replacing image subregions with style-transferred patches. Our approach first applies a…

Computer Vision and Pattern Recognition · Computer Science 2025-09-29 Qikai Yang , Cheng Ji , Huaiying Luo , Panfeng Li , Zhicheng Ding

Spectroscopic redshift surveys are key tools to trace the large-scale structure (LSS) of the Universe and test the $\Lambda$CDM model. However, using redshifts as distance proxies introduces distortions in the 3D galaxy distribution. If…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-09 Edoardo Maragliano , Punyakoti Ganeshaiah Veena , Giulia Degni , Enzo Franco Branchini

In the next years, several cosmological surveys will rely on imaging data to estimate the redshift of galaxies, using traditional filter systems with 4-5 optical broad bands; narrower filters improve the spectral resolution, but strongly…

Medical image segmentation models are often trained on curated datasets, leading to performance degradation when deployed in real-world clinical settings due to mismatches between training and test distributions. While data augmentation…

Computer Vision and Pattern Recognition · Computer Science 2025-05-16 Puru Vaish , Felix Meister , Tobias Heimann , Christoph Brune , Jelmer M. Wolterink

Photometric redshift estimation is a key requirement for modern large-area surveys, where spectroscopic measurements are observationally prohibitive. Seyfert II galaxies provide a particularly challenging test case due to the combined…

Astrophysics of Galaxies · Physics 2026-04-23 Uzay Aydin

We present a catalogue of photometric redshifts for galaxies from DESI Legacy Imaging Surveys, which includes $\sim0.18$ billion sources covering 14,000 ${\rm deg}^2$. The photometric redshifts, along with their uncertainties, are estimated…

Astrophysics of Galaxies · Physics 2025-02-25 Xingchen Zhou , Nan Li , Hu Zou , Yan Gong , Furen Deng , Xuelei Chen , Qian Yu , Zizhao He , Boyi Ding

Currently, style augmentation is capturing attention due to convolutional neural networks (CNN) being strongly biased toward recognizing textures rather than shapes. Most existing styling methods either perform a low-fidelity style transfer…

Computer Vision and Pattern Recognition · Computer Science 2023-08-30 Felipe Moreno-Vera , Edgar Medina , Jorge Poco

Large sets of objects with spectroscopic redshift measurements will be needed for imaging dark energy experiments to achieve their full potential, serving two goals:_training_, i.e., the use of objects with known redshift to develop and…

Noisy distance estimates associated with photometric rather than spectroscopic redshifts lead to a mis-estimate of the luminosities, and produce a correlated mis-estimate of the sizes. We consider a sample of early-type galaxies from the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Graziano Rossi , Ravi K. Sheth , Changbom Park

We measure the influence of image augmentations and training dataset size when training a deep neural network to classify galaxy morphology. Data augmentation is an integral step when training machine learning models and often astronomers…

Instrumentation and Methods for Astrophysics · Physics 2026-04-29 Leon H. Butterworth , Ashley Spindler

We describe the construction of a template set of spectral energy distributions (SEDs) for the estimation of photometric redshifts of luminous red galaxies (LRGs) with a Bayesian template fitting method. By examining the color properties of…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-24 Natascha Greisel , Stella Seitz , Niv Drory , Ralf Bender , Roberto Saglia , Jan Snigula

The Next Generation Space Telescope (NGST) will gather unprecedented spectro-photometric data on galaxies out to the highest redshifts. It is therefore crucial to identify the spectro-photometric diagnostics within reach of NGST, which will…

Astrophysics · Physics 2009-09-25 S. Charlot

Spatial Transformer Networks (STNs) estimate image transformations that can improve downstream tasks by `zooming in' on relevant regions in an image. However, STNs are hard to train and sensitive to mis-predictions of transformations. To…

Machine Learning · Computer Science 2022-06-16 Pola Schwöbel , Frederik Warburg , Martin Jørgensen , Kristoffer H. Madsen , Søren Hauberg

WL measurements have well-known shear estimation biases, which can be partially corrected for with the use of image simulations. We present an analysis of simulated images that mimic HST/ACS observations of high-redshift galaxy clusters,…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-26 B. Hernandez-Martin , T. Schrabback , H. Hoekstra , N. Martinet , J. Hlavacek-Larrondo , L. E. Bleem , M. D. Gladders , B. Stalder , A. A. Stark , M. Bayliss

Data augmentation is often used to enlarge datasets with synthetic samples generated in accordance with the underlying data distribution. To enable a wider range of augmentations, we explore negative data augmentation strategies (NDA)that…

Computer Vision and Pattern Recognition · Computer Science 2021-02-11 Abhishek Sinha , Kumar Ayush , Jiaming Song , Burak Uzkent , Hongxia Jin , Stefano Ermon

Data augmentation is a powerful technique to improve performance in applications such as image and text classification tasks. Yet, there is little rigorous understanding of why and how various augmentations work. In this work, we consider a…

Machine Learning · Computer Science 2023-07-28 Sen Wu , Hongyang R. Zhang , Gregory Valiant , Christopher Ré

Large-scale astronomical surveys can capture numerous images of celestial objects, including galaxies and nebulae. Analysing and processing these images can reveal intricate internal structures of these objects, allowing researchers to…

Instrumentation and Methods for Astrophysics · Physics 2023-11-02 Peng Jia , Jiameng Lv , Runyu Ning , Yu Song , Nan Li , Kaifan Ji , Chenzhou Cui , Shanshan Li

Determining the redshift distribution $n(z)$ of galaxy samples is essential for several cosmological probes including weak lensing. For imaging surveys, this is usually done using photometric redshifts estimated on an object-by-object…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-31 Jörg Herbel , Tomasz Kacprzak , Adam Amara , Alexandre Refregier , Claudio Bruderer , Andrina Nicola

Data-augmentation is key to the training of neural networks for image classification. This paper first shows that existing augmentations induce a significant discrepancy between the typical size of the objects seen by the classifier at…

Computer Vision and Pattern Recognition · Computer Science 2022-01-21 Hugo Touvron , Andrea Vedaldi , Matthijs Douze , Hervé Jégou
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