1. An inspection apparatus to inspect a plurality of read images each of which are read from a plurality of printed images output from an image forming apparatus, the inspection apparatus comprising: a memory 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 master image generated from image data of the previously printed image; and a processor 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 master image based on the image data of the currently printed image; correct pixel positions of one of the currently read image or the master image using the correction parameter for the previously read image to generate a corrected image, the corrected image including a reference point previously set; extract a reference point in the other one of the master image or the currently read image that is not corrected, which corresponds to the reference point set in the corrected image; calculate a correction parameter for the currently read image, which is capable of correcting a positional shift in the currently read image with respect to the master image, based on difference between the reference point in the corrected image and the reference point in the other one of the master image or the currently read image that is not corrected; inspect the currently read image based on 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; and update the correction parameter for the previously read image that is stored in the memory, with the correction parameter for the currently read image.