1. An image processing apparatus comprising: a memory configured to store instructions; and a processor connected to the memory and configured to execute the instructions to: acquire a blurred image; acquire a blur estimation area corresponding to at least a part of the blurred image; generate an estimated blur based on the acquired blur estimation area by performing iterative calculation processing that repeats correction processing and estimation processing, the correction processing correcting a blur included in information relating to a signal in the blur estimation area to generate information relating to a correction signal, and the estimation processing estimating a blur based on the information relating to the signal and the information relating to the correction signal; generate, as the information relating to the correction signal, information relating to a plurality of correction signals using a plurality of calculation expressions different from each other in at least one correction processing during the iterative calculation processing; and correct at least a part of the blurred image based on the estimated blur.