Flexible digital projector calibration method based on per-pixel distortion measurement and correction

- The projector distortion characteristic on each pixel can be measured independently.
- The non-perpendicularity between the optical axis and image plane is corrected.
- This high-accuracy method avoids residual caused by parametric distortion model.
- The projector calibration method can be implemented conveniently and flexibly.

When a digital projector is applied in high precision applications, the intrinsic parameters and distortion characteristics should be calibrated precisely. In this paper, a flexible full-field projector calibration method is proposed without any approximate distortion model. With planar homography theory and fringe projection technique, the projector distortion characteristic on each pixel can be measured independently and an initial distortion map is generated. The intrinsic parameters are calibrated afterwards. Then, the initial distortion map can be refined by correcting the non-perpendicularity between the optical axis and image plane. The original pattern to be projected is corrected with the refined distortion map. Thus, the calibrated projector can be regarded as an ideal projector conforming to the pinhole model. Experimental results show a nearly ideal residual map for the corrected projection pattern. In addition, the proposed calibration method is flexible without any sophisticated ancillary equipment or complicated procedure.