Patent ID: 7609228

Claim:
A keystone correction system, comprising: an interface to select a maximally distorted corner on a projected image; and a keystone controller to distort image data responsive to moving the maximally distorted corner and responsive to an identification of a tilt and a rotation of the system, the keystone controller comprising: a plurality of vertical offset registers comprising a column even register (YE), a column odd register (YO), and a column increment (1 st order term) register (YI); a plurality of vertical registers comprising a line position register (VDN), an increment per line (1 st order term) register (VDNI), and an increment per column register (VDNPI); a vertical enable register; a vertical scalar to vertically scale image data responsive to at least the vertical offset registers, the vertical registers, and the vertical enable register; a plurality of horizontal offset registers comprising a row even register (XE), a row odd register (XO), and a row increment (1 st order term) register (XI); a plurality of horizontal registers comprising a row position register (HDN), an increment per line (1 st order term) register (HDNI), an increment per line (2 nd order term) register (HDNII), an increment per column (1 st order term) register (HDNPI), and an increment per column (2 nd order term) register (HDNPII); a horizontal enable register; and a horizontal scalar to horizontally scale the vertically scaled image data responsive to at least the horizontal offset registers, the horizontal registers, and the horizontal enable register.