Calibration of telecentric cameras with an improved projection model

Telecentric lenses have been used for high-precision visual measurement systems because of their unique imaging properties, whereas the principal point is usually not considered in the projection model for calibration. Here, we propose an improved model containing the principal point for calibrating telecentric cameras. Detailed mathematical derivation from the pinhole model is performed. Then, an experimental setup is established. Two different telecentric cameras are used for verification. The results prove that calibrating telecentric cameras based on the improved model considering the principal point can achieve up to 55.37% higher accuracy and better stability than the common projection model without the principal point.