1. A method for authenticating scanners, including fingerprint area scanners, said method comprising: using an electronic processing circuit configured to perform the following, (a) providing at least one enrolled image acquired by a scanner and at least one query image acquired by a scanner; (b) selecting a plurality of pixels of said at least one enrolled image as enrolled selected pixels and a plurality of pixels of said at least one query image as query selected pixels; (c) masking pixels of said enrolled selected pixels as enrolled useful pixels and pixels of said query selected pixels as query useful pixels, wherein said masking uses at least one predetermined criterion to determine said useful pixels; (d) computing a similarity score between the common pixels of said enrolled useful pixels and of said query useful pixels; and (e) comparing said similarity score with a threshold value to determine whether said at least one query image has been acquired by the same scanner that acquired said at least one enrolled image.