We describe a simple and fast method to correct ellipticity measurements of galaxies from the distortion by the instrumental and atmospheric point spread function ( PSF ) , in view of weak lensing shear measurements .
The method performs a classification of galaxies and associated PSFs according to measured shape parameters , and corrects the measured galaxy ellipticites by querying a large lookup table ( LUT ) , built by supervised learning .
We have applied this new method to the GREAT10 image analysis challenge , and present in this paper a refined solution that obtains the competitive quality factor of Q = 104 , without any shear power spectrum denoising or training .
Of particular interest is the efficiency of the method , with a processing time below 3 ms per galaxy on an ordinary CPU .