Galaxy image deconvolution for weak gravitational lensing with unrolled plug-and-play ADMM

Removing optical and atmospheric blur from galaxy images significantly improves galaxy shape measurements for weak gravitational lensing and galaxy evolution studies. This ill-posed linear inverse problem is usually solved with deconvolution algorithms enhanced by regularisation priors or deep learning. We introduce a so-called ’physics-informed deep learning’ approach to the Point Spread Function (PSF) deconvolution problem in galaxy surveys. We apply algorithm unrolling and the Plug-and-Play technique to the Alternating Direction Method of Multipliers (ADMM), in which a neural network learns appropriate hyperparameters and denoising priors from simulated galaxy images. We characterize the time-performance trade-off of several methods for galaxies of differing brightness levels, as well as our method’s robustness to systematic PSF errors and network ablations. We show an improvement in reduced shear ellipticity error of 38.6 per cent (SNR=20)/45.0 per cent (SNR=200) compared to classic methods and 7.4 per cent (SNR=20)/33.2 per cent (SNR = 200) compared to modern methods (https://github.com/Lukeli0425/Galaxy-Deconv).