arXiv:2601.08666astro-ph.IMcs.CV2026-01

U-Net无需先验信息,可端到端完成天文图像盲反卷积。

Blind Deconvolution in Astronomy: How Does a Standalone U-Net Perform?

  • 用U-Net直接学习无先验的天文图像反卷积,通过MSE损失训练。
  • 训练数据超5000张后性能饱和,40,000张时优于经典Tikhonov方法。
  • 模型对未知观测条件泛化良好,且学习到几何自适应谐波基底。

本研究探讨了U-Net架构在无任何点扩散函数(PSF)或噪声特性先验的情况下,是否能实现天文图像的端到端盲反卷积。利用GalSim工具包模拟真实天文观测,包含随机变换、PSF卷积(光学与大气效应)及高斯白噪声。在大小为48×48的COSMOS真实星系数据集上,使用均方误差(MSE)损失训练不同规模的U-Net模型,最多达40,000张图像。通过峰值信噪比(PSNR)、结构相似性(SSIM)和余弦相似度评估性能,后者用于双模型框架分析解的稳定性。结果表明,随着训练样本增加,模型性能持续提升,在超过5,000张图像后趋于饱和。余弦相似度分析显示独立训练模型收敛,解稳定。尤其在低PSNR/中等SSIM的挑战条件下,其表现优于近似理想化的Tikhonov方法。模型对未见的视宁度和噪声条件具有良好泛化能力,但最优性能需在训练参数中包含验证条件。合成$C^α$图像实验进一步支持:U-Net学习到一种几何自适应谐波基底,类似去噪任务中的稀疏表示。这些结果与近期关于其自适应学习能力的数学分析一致。

原文摘要 · Abstract (English)

Aims: This study investigates whether a U-Net architecture can perform standalone end-to-end blind deconvolution of astronomical images without any prior knowledge of the Point Spread Function (PSF) or noise characteristics. Our goal is to evaluate its performance against the number of training images, classical Tikhonov deconvolution and to assess its generalization capability under varying seeing conditions and noise levels. Methods: Realistic astronomical observations are simulated using the GalSim toolkit, incorporating random transformations, PSF convolution (accounting for both optical and atmospheric effects), and Gaussian white noise. A U-Net model is trained using a Mean Square Error (MSE) loss function on datasets of varying sizes, up to 40,000 images of size 48x48 from the COSMOS Real Galaxy Dataset. Performance is evaluated using PSNR, SSIM, and cosine similarity metrics, with the latter employed in a two-model framework to assess solution stability. Results: The U-Net model demonstrates effectiveness in blind deconvolution, with performance improving consistently as the training dataset size increases, saturating beyond 5,000 images. Cosine similarity analysis reveals convergence between independently trained models, indicating stable solutions. Remarkably, the U-Net outperforms the oracle-like Tikhonov method in challenging conditions (low PSNR/medium SSIM). The model also generalizes well to unseen seeing and noise conditions, although optimal performance is achieved when training parameters include validation conditions. Experiments on synthetic $C^α$ images further support the hypothesis that the U-Net learns a geometry-adaptive harmonic basis, akin to sparse representations observed in denoising tasks. These results align with recent mathematical insights into its adaptive learning capabilities.

盲反卷积U-Net天文图像深度学习

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