Abstract: A method for calibrating an image acquisition device, including determining the distance between the image acquisition device and a reference plane. The method including: acquiring at least two images of a calibration pattern located, for each image, at different distances from the image acquisition device and a constant distance from the reference plane, and having a plurality of characteristic points, preferably aligned, at different distances from the reference plane; and for each characteristic point, determining the difference between the positions of the same characteristic point from one image to another; and selecting certain characteristic points according to a predetermined condition; and estimating the distance from the acquisition device to the reference plane on the basis of the respective differences at the selected characteristic points.