Patent US 8,322,863

An apparatus and a method are disclosed for automated projection image adjustments for a portable projection device. In one embodiment of the invention, the apparatus periodically polls a tilt sensor inside the portable projection device and uses the tilt sensor reading as a key to a lookup table which stores pre-computed visual distortion adjustment values. Furthermore, the apparatus can also poll a distance measurement sensor to measure a distance between a projector lens and a presumed projection surface periodically. The measured distance value can also be used as an additional parameter to the key for the lookup table to retrieve appropriate visual distortion adjustment values which are pre-computed and stored in the lookup table. The fast pre-computed adjustment value retrieval without real-time computation of graphical transformations to correct the visual distortions minimizes processor load, energy consumption, and processing delays for projection image corrections.