Efficient nonlinear geometric distortion correction for scanned laser pico projectors

Scanned laser pico projectors utilising laser light sources and microelectromechanical systems mirror devices introduce geometric distortion to the displayed images because of nonlinear mirror driving methods. A pre-processing algorithm is proposed that corrects the nonlinear geometric distortion of scanned laser pico projectors. The distortion is modelled as blockwise homography transforms. The geometry of the images being displayed is pre-distorted using the pixel indices obtained by the backward blockwise homography transforms. The pre-distorted images are displayed by the pico projector whose geometrical distortion undoes the pre-distortion such that distortion-free images can be displayed. The proposed algorithm requires a small amount of information stored in the memory and three bilinear interpolations per pixel, thus providing an efficient way to correct nonlinear distortion without additional optical components, such as aspherical lenses.