Correction of distorted images

摘要

A system for correcting distortion in projected images comprises a projection TV system (200) and a distortion information extracting unit (201). A reference image generator (28) sends a reference image, such as a grid pattern, to the TV system. The reference image is projected via CRT (25) and an optical system (26) upon a screen (not shown). A camera (27) captures the projected reference image and sends it to a distortion information extractor (29). The distortion information extractor compares the projected reference image with the original reference image and judges whether the image has undergone keystone or pincushion distortion during projection. Distortion parameters are determined and stored in the distortion correcting memory (24-4) enabling the controller (24-2) to warp the image of the 1st frame memory (24-1) before it is output to the 2nd frame memory (24-3). The resultant 'prewarped' image is projected and should result in a corrected image. The process is repeated repeatedly to update the distortion parameters until the projected reference image is discerned to be undistorted when compared to the original reference image.