1. A method of removing an artifact resulting from an in-line illumination device of an imaging system from an image of an object to be analyzed, the method comprising: obtaining a first image of an artifact resulting from an in-line illumination device of an imaging system using a first artifact illumination level; imaging an object to be analyzed using the imaging system wherein the in-line illumination device is using an object illumination level; and subtracting respective pixel values of an artifact image from respective values of the object image on a pixel address-by-pixel address basis.