1. An inspection system comprising: a first inspection tool comprising: a first camera for obtaining first images of a wafer; a first inspection light source for illuminating the wafer; and a first controller coupled to the first camera and the first inspection light source, the first controller configured for performing light source flat field correction, optical image warping correction, and optical image scale correction of the first images; a second inspection tool separate from the first inspection tool and of a same type as the first inspection tool, the second inspection tool comprising: a second camera for obtaining second images of the wafer: a second inspection light source for illuminating the wafer: and a second controller coupled to the second camera and the second inspection light source, the second controller configured for performing light source flat field correction, optical image warping correction, and optical image scale correction of the second images; wherein the first inspection tool and the second inspection tool are configured for product setup sharing such that the first images substantially match the second images, and wherein the first controller is configured to perform flat field correction by: illuminating a target with the first inspection light source; determining an average gray value of a sensor array of the first camera focused on the target; determining a normalizing factor at each pixel location of the sensor array by dividing the average gray value of the sensor array by the gray value at that pixel; and multiplying the normalizing factor for each pixel location to corresponding pixels of an inspection image.