Computer graphics processing and selective visual display system – Computer graphics processing – Adjusting level of detail
Reexamination Certificate
1998-03-31
2002-09-24
Zimmerman, Mark (Department: 2772)
Computer graphics processing and selective visual display system
Computer graphics processing
Adjusting level of detail
C345S215000
Reexamination Certificate
active
06456288
ABSTRACT:
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
FIELD OF THE INVENTION
The present invention relates generally to the field of computer graphics and specifically to the field of creating a database with improved performance and resolution for large areas rendered in real time. The present invention presents a method and apparatus for creating a database that enhances the resolution of a scene and renders more efficiently in real time.
BACKGROUND OF THE INVENTION
Typical graphics rendering systems utilize a geotypical texture database, wherein geotypical textures are stored in memory and utilized to fill in textures for every occurrence of a particular texture, for example a cornfield. The geotypical cornfield texture is held in memory and used repeatedly on every polygon that represents a small section of the cornfield. Typically, there are many corn field texture polygons requiring the geotypical cornfield texture to be used thousands of times in a scene containing cornfields. Thus, such a geotypical database would use a large number of polygons to represent the surface of the earth.
Real time rendering requires that each polygon undergo a mathematical transformation, a matrix multiplication within each display frame to map each polygon from world coordinates to display coordinates. Typical graphics rendering systems have limited processing power to render a large number of polygons in real time, thus the presence of the polygons slows down system performance during real time rendering. Thus, there is a need for a method and apparatus that reduces the number of polygons that must be processed in real time rendering.
Current rendering systems can display large geospecific images, however, resolution of those graphics rendering systems is limited to the resolution of the source imagery. Thus, there is a need for a method and apparatus that enables enhancement of rendered imagery beyond the resolution of the source imagery.
There is also a shortage of high-resolution imagery data coverage worldwide. In many cases only low-resolution imagery is available and in some cases no imagery is available. Thus, there is a need for a method and apparatus that enables the creation of real time scenery in areas where there is no source imagery available.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus for building a database off-line that can be used to efficiently render a scene in real time. The present invention enables creation of a database comprised of high-resolution models incorporated into lower-resolution source imagery. The present invention renders and captures an orthographic projection of a scene and stores it as a pixel representation of the rendered imagery and the models. The pixel representation is stored in a database for rendering in real time. The resulting database can be rendered more efficiently in real time than databases built using previously known techniques.
The database provides improved resolution and improved rendering performance. Scene resolution is enhanced by substituting images of high-resolution geotypical textures and models in place of lower-resolution source imagery. The present invention builds a database generated from an orthographic rendering of a enhanced scene wherein images of high-resolution models (SPLOT models) have been inserted into lower-resolution source imagery. The rendered representation of the scene is stored in a database for rendering in real time.
The present invention builds a database containing high-resolution pixel representations and lower-resolution polygonal representations, thereby enabling switching between the pixel representation for two-dimensional rendering and the polygonal representation of a feature for three dimensional rendering in a scene. The present invention generates a database that enables efficient rendering in real time.
The present invention removes excess polygons from culture to speed up the real time rendering process. A visual database generally includes polygons that represent the undulating surface of the terrain, plus additional polygons that represent cultural features on the terrain. The present invention reduces the polygons that represent cultural features by replacing them with textures derived from said polygons. For example, a database may contain polygons with a geotypical cornfield texture, said polygons coplanar with the polygons representing the terrain surface; and other polygons with a geotypical runway texture, said polygons also coplanar with the terrain surface; and other polygons that represent paint markings on said runway, coplanar with the runway polygons; and polygons used to represent three-dimensional features (for example, buildings) on the terrain. All such cultural polygons may be replaced by a single large texture applied to the terrain surface polygons, said texture derived from the polygons representing the cornfields, the runways with its surface markings, and the buildings. Said texture may be considered as pseudo-geospecific. inasmuch as it appears very similar to high-resolution imagery, were such imagery available.
The present invention provides a method and apparatus that enables construction of a database having fewer polygons to enable higher performance rendering in real time. The present invention also enables creation of synthetic high-resolution imagery where no source imagery is available. The present invention also provides an apparatus and method for enhancing the resolution of a representation of source imagery.
The present invention renders a polygonal representation of a scene (geometry and texture) containing high-resolution models, as an orthographic projection and then captures a pixel representation of an orthographic projection of the scene. The orthographic pixel textures are combined into a composite texture. The resulting composite texture is then draped over the surface contour. The composite texture can be rendered rapidly because the bulk of the cultural features have been transformed from a polygonal representation to a texture representation. The initial underlying polygons, representing the culture which slow down real time rendering, are no longer a part of the scene. The present invention also removes two-dimensional coplanar polygons. Thus, the present invention enables rendering a scene with a fraction of the polygons utilized in typical graphical rendering systems. The present invention provides essentially the same scene content with an order of magnitude reduction in the number of polygons, an increase in resolution and additional coverage in areas where source imagery is unavailable.
Resolution is effectively increased in selected target areas. For example, in a five-meter resolution source image, the present invention enables an operator to mark, locate and digitize features such as roads buildings and fields that appear in the image. For example, a road in a five-meter resolution image may be visible but not as sharp as desired. The present invention provides a method and apparatus for sharpening the presentation of the road in the image. The present invention provides a method and apparatus for creating models comprised of polygons and high-resolution textures to replace or create the features in an image, thereby increasing the overall imagery resolution.
The present invention enables replacement of original features with sharper, higher-resolution models. The same process can be used to create and add features such as parking lots, buildings and fields that may or may not appear in the source imagery. The resulting intermediate image comprises a combination of the five-meter resolution source imagery and the higher-resolution models. The combination yields an image with higher resolution th
Brockway Dan E
McDonald Richard M.
Walters Charles B.
Weiblen Michael E
Computer Associates Think Inc.
Padmanabhan Mano
Zimmerman Mark
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