Method and device for estimating obsolute size dimensions of test object

A method for estimating the absolute size dimensions of a test object based on image data of the test object, namely a face or part of a person. The method includes receiving image data of the test object, determining a first model of the test object based on the received image data, and aligning and scaling the first model to a first average model that includes an average of a plurality of first models of reference objects being faces or parts of faces of reference persons. The first models of the reference objects are of a same type as the first model of the test object. The method further includes determining a shape difference between the test object and an average of the reference objects, determining a second model of the test object with an estimated scale based on (i) the determined shape difference, (ii) a statistical operator that is indicative of a statistical correlation between shape and size dimensions of the reference objects, and (iii) a second average model, and determining the size dimensions of the test object based on the second model of the test object.