1. An inspection imaging system configured to use magnification correction from multiple focus planes, said system comprising: an imager comprising an image acquisition device and a lens in optical communication with said image acquisition device; a controller comprising: a user interface; one or more memory devices; and one or more processors communicatively coupled to said user interface and said one or more memory devices, said one or more processors programmed to: acquire a plurality of images of a target, each image of the plurality of images acquired in a different focus plane of the multiple focus planes with respect to the target using the same optical parameters of the imager for each image; determine a distance between said lens used in acquiring the plurality of images and the target; determine a magnification of each acquired image; determine a magnification correction with respect to a reference target of known dimensions; determine a change in a size of the target; and output the determined change in the size of the target to a maintenance planning computer system communicatively coupled to the inspection imaging system.