The present invention relates to a method for estimating an absolute size of an inspection object (32) based on image data of the inspection object (32), the inspection object (32) being a face of a subject or a part of a face. The method includes: receiving the image data of the inspection object (32) (S101)； determining the first model (30) of the inspection object (32) based on the received image data (S102) A first model (30) having an unknown scale； and aligning and scaling the first model (30) of the test object (32) with respect to the first average model, The average model includes an average of a plurality of first models of the reference object that is the face of the reference person or a part of the face, and the first average model of the reference object is the first model (30) of the inspection object (32). Same type There is a step having an unknown scale； and by determining the alignment between the test object (32) and the difference between the scaled first model and the first average model, the test object (32) and the reference object Determining a shape difference between the mean； (i) a determined shape difference； (ii) a statistical operator indicating a statistical correlation between the shape and size dimension of the reference object； Determining a second model (34) of the test object (32) having an estimated scale based on the two average model, wherein the second average model is an average of a plurality of second models of the reference object The second model of the reference object is of the same type as the second model of the inspection object and has a known scale； and the inspection object based on the second model (34) of the inspection object (32) ( 32) And determining the size dimensions.本発明は、検査対象（３２）の画像データに基づいて検査対象（３２）の絶対的なサイズ寸法を推定するための方法に関し、検査対象（３２）は被検者の顔又は顔の一部であり、当該方法は：検査対象（３２）の画像データを受け取るステップ（Ｓ１０１）と；受け取った画像データに基づいて検査対象（３２）の第１モデル（３０）を決定するステップ（Ｓ１０２）であって、第１モデル（３０）は未知のスケールを有するステップと；検査対象（３２）の第１モデル（３０）を第１平均モデルに対して位置合わせ及びスケーリングする
