1. A method for acquiring biometric data of an object comprising: acquiring a first digital two-dimensional image of a first set of points on a surface of the object from a first taking direction using a first optical scanning sensor; acquiring a second digital two-dimensional image of the first set of points from a second taking direction using a second optical scanner at least approximately simultaneously with the acquiring of the first image; calculating a three-dimensional model of the object using the first and second digital two-dimensional images, wherein the calculating is performed using a geometric basic model of the object, the geometric basic model being simplified in comparison to the object, and wherein height deviations between the geometric basic model and the object are determined, the height deviations being orthogonal to a local surface of the geometric basic model; acquiring a first calibration image of a set of defined points on a surface of a calibration object from the first taking direction using the first optical scanning sensor; and acquiring a second calibration image of the set of defined points from the second taking direction using the second optical scanning sensor at least approximately simultaneously with the acquiring of the first image.