Alonso-Caneiro D, Sampson DM, Chew AL, Collins MJ, Chen FK. Use of focus measure operators for characterization of flood illumination adaptive optics ophthalmoscopy image quality. Biomed Opt Express. 2018 Jan 18;9(2):679-693. doi: 10.1364/BOE.9.000679. eCollection 2018 Feb 1. PMID: 29552404