1. An inspection apparatus configured to inspect a plurality of read images each of which are subsequently read from a plurality of printed images output from an image forming apparatus, the inspection apparatus comprising: a memory configured to store a correction parameter for a previously read image read from a previously printed image, the correction parameter being calculated to correct a positional shift in the previously read image with respect to a first master image generated from image data of the previously printed image; and a processor configured to, obtain a currently read image that is read from a currently printed image output from the image forming apparatus; obtain image data of the currently printed image, which is used by the image forming apparatus to form the currently printed image; generate a second master image based on the image data of the currently printed image; correct pixel positions of one of the currently read image or the second master image using the correction parameter for the previously read image to generate a corrected image, the corrected image including a first reference point previously set; extract a second reference point in the other one of the second master image or the currently read image that is not corrected, which corresponds to the first reference point set in the corrected image; calculate a correction parameter for the currently read image for correcting a positional shift in the currently read image with respect to the second master image, based on a difference between the first reference point and the second reference point; inspect the currently read image based on a difference between the corrected image and the other one of the master image or the currently read image that is not corrected to generate an inspection result indicating whether the currently printed image sufficiently reproduces the image data of the currently printed image; calculate an average correction value based on one or more of the correction parameter for the currently read image and correction parameters each obtained for each one of a number of previously read images; and update the correction parameter for the previously read image that is stored in the memory, with the calculated average correction value, wherein the updated correction parameter is to be used for an image to be read subsequent to the currently read image.