Method and apparatus for spherical panning

• US 4,734,690 A
• Filed: 04/06/1987
• Issued: 03/29/1988
• Est. Priority Date: 07/20/1984
• Status: Expired due to Term

• Current Assignee: American Video Graphics LP
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Waller, William G.
• Primary Examiner(s): Brigance, Gerald L.
• Assistant Examiner(s): Brier, Jeffery A.
• Application Number:
  US07/033,851
• Time in Patent Office: 358 Days
• Field of Search: 340/723, 340/724, 340/727, 340/729, 340/731, 364/521, 364/522
• US Class Current: 345/427
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour
• CPC Class Codes: G06T 15/20 Perspective computation

Abstract

A graphics display terminal performs a pan operation with respect to a view motion center to effectuate spherical panning, thereby providing perspective and non-perspective views. Three dimensional instructions stored in terminal memory are re-transformed in accordance with a panned direction. Also a zoom feature is provided so that displayed images may be magnified as desired.

Claims

1. A three-dimensional panning method comprising the steps of:

storing applied graphic information representing a three-dimensional object in a first three-dimensional coordinate modeling space;

defining a second three-dimensional coordinate space as a viewing space from which the object may be viewed, the viewing space being movable at a selected radial distance around a selected reference point in the modeling space;

inputting and storing further information including panning information specifying a position from which to view the object;

moving the viewing space to the specified position in response to the panning information, effecting a transform of the coordinates of the object to the viewing space and to a two-dimensional coordinate screen space; and

displaying a two-dimensional image of the transformed coordinates, providing a view of the object from the panned-to-position.

2. The method of claim 1 where the step of moving the viewing space includes the step of orienting said viewing space with respect to the object, by varying at least one of pitch, yaw, and roll attitudes of said viewing space.

3. The method of claim 1 where the step of inputting further information includes the step of identifying a center of projection relative to the specified view position.

4. The method of claim 1 where the step of inputting further information includes the step of specifying a radial distance at which the object may be viewed.

5. The method of claim 1 where the step of inputting further information includes the step of specifying viewing window size as a degree of magnification of the displayed image.

6. The method of claim 1 where the step of inputting further information includes the step of specifying one of parallel and perspective transforms.

7. Apparatus for performing a three-dimensional panning operation, comprising:

memory means for storing entered information including applied graphic and panning information and a control program, the graphic information representing a three-dimensional object in a first three-dimensional coodinate modeling space;

input means for entering information including panning information for panning to a selected position from which to view the object;

processing means coupled to the input and memory means, and responsive to the panning information and execution of the program, for defining a second three-dimensional coordinate space as a viewing space from which the object may be observed, and for moving the viewing space, a selected radial distance around a selected reference point in the modeling space, to the selected position, effecting a transform of the coordinates of the object to the viewing space and to a two-dimensional coordinate screen space; and

means for displaying a two-dimensional image of the transformed coordinates, providing a view of the object from the panned-to position.

8. The apparatus of claim 7 wherein the processing means includes a means for orienting the viewing space with respect to the object, by varying at least one of pitch, yaw, and roll attitudes of said viewing space.

9. The apparatus of claim 7 wherein the input means includes a means for identifying a center of projection relative to the selected view position.

10. The apparatus of claim 7 wherein the input mean includes a means for specifying a radial distance at which the object may be viewed.

11. The apparatus of claim 7 wherein the input means includes a means for specifying a view window size as a degree of magnification of the displayed image.

12. The apparatus of claim 7 wherein the input means includes a means for specifying one of parallel and perspective transforms.