The present invention relates to a method and a corresponding device for determining nominal mechanical data for an electronic device by means of automatic image processing of a digital image of a specimen of said electronic device. In the method an object in said digital image, which object corresponds to said specimen, is identified and appearance data for the appearance of the identified object are determined. Then, at least some of the determined appearance data are compared with a stored set of nominal appearance data, which nominal appearance data are based on a priori knowledge of appearances of electronic devices, and at least some nominal appearance data of the set of nominal appearance data are selected. Finally, the nominal mechanical data of the electronic device is determined in accordance with the selected nominal appearance data and at least some of the determined appearance data.