Beam based calibration for optical imaging device

Well calibrated optical imaging devices are needed in 3DTV. An optical imaging device, for example camera and projector, maps beams in object space into 2D points in image space. The mapping function, or lens distortion, must be calibrated in order to build the correct object-image relation. Current calibration methods try to model the distortion by analytical functions. This will easily fail when the distortion is irregular, especially near the edge of the view field. In this paper, we propose a new flexible technique to easily and accurately calibrate single or combined optical imaging devices. We directly calculate the beam's vector in a device-based coordinate system for each sensor pixel element without analytically modeling the lens distortion. A TFT monitor, which displays fringe patterns, is used as calibration object. The imaging device is mounted on a computer controlled shift/rotation setup and observes the monitor at few (>2) different positions. The calibration for a fringe projection system has been implemented and the results will be demonstrated and compared to classical techniques to show the improvement of the new technique.