Automatic Projector Calibration for Curved Surfaces Using an Omnidirectional Camera

Abstract: This master’s thesis presents one approach to remove distortions generated by projecting onto non flat surfaces. By using an omnidirectional camera a full 360 dome could be calibrated and the corresponding angles between multiple projections could be calculated. The camera was modelled with the Unified Projection Model allowing any omnidirectional camera system to be used. Surface geometry was captured by using Gray code patterns, the optimal image centre was calculated as an quadratic optimisation problem and in the end a Spline surface countering the distortions was generated by using the FAST-LTS regression algorithm. The developed system used a RICOH THETA S camera calibrated by the omnidir module in openCV. A desirable result was achieved and during use of overlapping projectors a maximum error of 0.5° was measured. Testing indicates part of the error could have been introduced in the evaluation measurements. The resulting application is seen as a success and will be used by ÅF Technology AB during calibration of flight simulators.