Patent ID: 7131733

Claim:
A method for creating brightness filters: said brightness filters being adapted in use for an image projection system which projects divided images on a curved screen respectively from a plurality of projectors with adjacent ones of said divided images partially overlapped to reproduce a combined image, said filter being designed to adjust brightness of said divided images for harmonizing the brightness of the overlapping areas with the brightness of non-overlapping areas to make said combined image seamless, said method comprising the steps of: (a) producing a screen model reflecting a shape of said curved screen; (b) setting projection points respectively for projecting therefrom said divided images on said screen model, said projection points being different from each other in conformity with said projectors, respectively; (c) allocating one of said divided images to a reference image and allocating each of the adjacent divided images to a peripheral image; (d) setting a view point that is coincident with the projection point of said reference image; (e) obtaining a 2-dimensional reference area of said reference image that is rendered on said screen model and is viewed from said view point; (f) obtaining a 2-dimensional peripheral area of said peripheral image that is rendered on said screen model and is viewed from said view point; (g) extracting an overlapping area of said 2-dimensional reference area that overlaps with the 2-dimensional peripheral area; (h) making a brightness correction for either said overlapping area or said non-overlapping area with regard to said 2-dimensional reference area; (i) providing a brightness filter for said reference image that realizes said brightness correction; (j) allocating another divided image to said reference image and repeating the steps of (d) to (i) for providing said brightness filter for each of said divided images.