A UNIFYING "ANYCENTRIC" PINHOLE CAMERA MODEL FOR CALIBRATING ENTO-, TELE- AND HYPERCENTRIC LENSES

Simon Hartel, Christian Faber

In photogrammetry, camera calibration is often based on the well-known pinhole camera model [1] to describe the camera’s object-sided chief rays. However, this model only applies to widely used entocentric lenses, whereas optical imaging and metrology systems often use telecentric or sometimes even more exotic hypercentric lenses. These lenses literally facilitate new perspectives for mastering otherwise complex tasks by differing fundamentally in their chief ray paths – which is why the pinhole model has to be modified or cannot be used at all, depending on the camera lens used. This contribution shows, how the pinhole model can be unified for all these three lens types using Geometric Algebra [2]. It contains a smooth transition between the perspectives and is thus capable of directly calibrating telecentricity errors for the important case of telecentric lenses.