Enhancing Galaxy Classification with U-Net Variational Autoencoders for Image Denoising

TL;DR

This paper introduces a novel galaxy classification enhancement method using U-Net Variational Autoencoders for image denoising, significantly improving classification accuracy under noisy observational conditions.

Contribution

The study develops a U-Net VAE-based denoising approach that improves galaxy classification performance in noisy astronomical images, demonstrating its effectiveness across multiple models.

Findings

Denoised images have higher PSNR and SSIM scores.

Models trained on denoised images outperform those trained on noisy images.

The approach is adaptable to other astronomical datasets.

Abstract

AI-enhanced approaches are becoming common in astronomical data analysis, including in the galaxy morphological classification. In this study we develop an approach that enhances galaxy classification by incorporating an image denoising pre-processing step, utilizing the U-Net Variational Autoencoder (VAE) architecture and effectively mitigating noise in galaxy images and leading to improved classification performance. Our methodology involves training U-Net VAEs on the EFIGI dataset. To simulate realistic observational conditions, we introduce artifacts such as projected stars, satellite trails, and diffraction patterns into clean galaxy images. The denoised images generated are evaluated using Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM), to quantify the quality improvements. We utilize the denoised images for galaxy classification tasks using models such as DenseNet-201, ResNet50, VGG16 and GCNN. Simulations do reveal that, the models trained on denoised images consistently outperform those trained on noisy images, thus demonstrating the efficiency of the used denoising procedure. The developed approach can be used for other astronomical datasets, via refining the VAE architecture and integrating additional pre-processing strategies, e.g. in revealing of gravitational lenses, cosmic web structures.