1. A method of processing image data, comprising the steps of: measuring a haze value corresponding to each position on a wafer surface by using a wafer surface inspection device that irradiates a surface of a wafer with a laser light while the wafer is being rotated around a center of the wafer, and converts a light scattered on the wafer surface into an electric signal to implement detection; subjecting image data formed by the haze value corresponding to each position on the wafer surface to an image data filtering process in a X-Y direction to obtain first image data; subjecting image data formed by the haze value corresponding to each position on the wafer surface to an image data process along a direction in which the haze value is measured to remove a noise component to obtain second image data; and combining the first image data with the second image data to obtain third image data.