A method is used to generate a distortion model for a structured illumination microscopy (SIM) optical system. A sliding window is moved in relation to a plurality of images to define a plurality of sub-tiles. Each sub-tile represents a portion of the corresponding image. Parameters are estimated for each sub-tiles. The parameters include two or more parameters selected from the group consisting of modulation, angle, spacing, phase offset, and phase deviation. A full width at half maximum (FWHM) value associated with each sub-tile is estimated. A distortion model is estimated, based at least in part on a combination of the estimated parameters and FWHM values stored in the predetermined format and an estimated center window parameter. A two-dimensional image may be generated, based at least in part on the estimated distortion model. The two-dimensional image may include representations indicating where distortions occur in the optical system.