Limited-memory scaled gradient projection methods for real-time image deconvolution in microscopy

•We propose an acceleration strategy for a scaled gradient projection method.•A recent idea, based on Ritz values, is generalized to the constrained optimization framework.•The method is applied to solve image deconvolution problems in microscopy.•The new approach is able to exploit a clever limited-memory implementation, very effective for large-scale problems.•Numerical results show lower computational time compared to state-of-the-art Barzilai–Borwein-based approaches.