Image mapping system and process using panel shear transforms
AssigneeEvans & Sutherland Computer Corporation
InventorMichael A. Cosman
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Abstract
Images for non-planar display systems are generated using polygon definitions that are pre-distorted using panel shear transforms. Initially, panel shear transforms are generated based on the configuration and orientation of a screen, a projector and a viewer. Polygons defined in model space are mapped to a two-dimensional space and then transformed to a panel space using the panel shear transforms. This transformation technique enables the use of standard two-dimensional rendering processes to scan-convert the polygons.
Claims18
A computer graphics system for providing picture element (pixel) signals to a display for displaying a plurality of objects defined as irregularly shaped quadrilaterals in a model space, said pixel signals being generated from said objects and a plurality of panel transforms, said panel transforms being representative of a mapping of a plurality of panels between an image space, a curved surface and a two-dimensional space, said system comprising:
- an object memory for storing said objects;
- a panel transform generator for generating said panel transforms representative of said mapping of said panels between said image space, said curved surface and said two-dimensional space by mapping geometric parameters of the panels in the image space to corresponding geometric parameters in the two-dimensional space and substituting parallelograms for the irregularly shaped quadrilaterals;
- and
- a graphics processor for processing said objects using said panel transforms to provide said pixel signals.
A dome projection system including a tan-theta plane, comprising:
- a curved screen;
- an object memory for storing an object representative of an image having irregularly shaped quadrilaterals in the tan-theta plane to be displayed on said curved screen;
- a panel transform generator for generating a panel transform representative of a mapping from an image space to said screen and from said screen to a two-dimensional space, wherein said panel transforms are generated by mapping geometric parameters of the panels in the image space to corresponding geometric parameters in the two-dimensional space and substituting parallelograms for the irregularly shaped quadrilaterals;
- a graphics processor for processing said object and said panel transform to provide picture element data for display;
- and
- a display device for displaying said picture element data on said screen.
A computer graphics process for generating picture element data to display an image on a curved surface, comprising the steps of:
- defining an object representative of an image having irregularly shaped quadrilateral panels on a tan-theta plane to be displayed on said curved surface;
- defining a panel in an image space;
- generating a panel transform representative of a mapping of said panel to a two-dimensional space wherein parallelograms are substituted for the irregularly shaped quadrilaterals;
- and
- generating picture element data using said object and said panel transform, wherein two-dimensional arithmetic operations are used to generate the picture element data.
Dependencies are inferred from the claim text.