Correcting luminance for obliquely-projected displays

Projection-based products are becoming a competitive alternative for HDTV display. It is often impractical to orient a projector perpendicularly to the screen. However, oblique projection geometry is a major factor in display luminance non-uniformity. Feedback from an arbitrarily-positioned camera is used to find homography transformations between projector and screen. From this we determine the ratio of pixel areas to flatten the illumination field.