Avoiding oscillation in interactive animation

• US 5,384,908 A
• Filed: 12/30/1991
• Issued: 01/24/1995
• Est. Priority Date: 12/30/1991
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Robertson, George G., Mackinlay, Jock D.
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Elmore, Stephen C.
• Application Number:
  US07/814,138
• Time in Patent Office: 1,121 Days
• Field of Search: 395/128, 395/152, 340/725, 345/121, 345/122
• US Class Current: 345/475
• CPC Class Codes: G06T 13/00 Animation
• CPC Class Codes: G06T 2210/36 Level of detail

Abstract

Interactive animation is performed in cycles, between which detail control data is communicated so that oscillation of detail can be avoided by maintaining detail. A cycle obtains data indicating the speed with which it renders an image and stores detail control data that depends on the rendering speed. The detail control data indicates a level of detail at which an image is presented in a following cycle. The level of detail can be used in rendering the image by producing data defining the image from data defining a scene. The data defining the scene can include level defining data indicating a rendering at each of a set of levels. The detail control data also includes maintenance information for use in determining whether to maintain detail. In one approach, the maintenance information indicates whether a level of detail is being maintained and a hold speed; the current rendering speed is compared with the hold speed and with a threshold speed in deciding whether to maintain detail. In another approach, the maintenance information also indicates a level of detail being maintained, so that if the current cycle has the same level of detail and rendering speed, the level and speed are continued. In this approach, the level of detail and rendering speed can be values on a detail/speed scale to permit direct comparison, and decisions about increasing and decreasing detail can be based on the relation between detail and speed, with the objective of providing a level of detail at which the designer'"'"'s preferred rendering speed can be achieved.

Claims

1. A method of operating a system that includes:

a display;

memory;

the memory storing scenes data defining a set of scenes; and

a processor connected for accessing the scenes data in the memory and also connected for controlling the display to present images;

the method comprising a sequence of rendering steps, each rendering step comprising substeps of;

using the scenes data to produce respective image defining data defining a respective image;

controlling the display to present the respective image as defined by the respective image defining data;

obtaining respective rendering speed data indicating a speed with which the substep of using the scenes data is performed; and

using the respective rendering speed data to obtain respective detail control data for use in controlling image detail to avoid oscillation of detail;

the substep of using the respective rendering speed data comparing the rendering speed with a threshold speed;

the threshold speed being a speed above which display features in an image are perceptible as continuations of display features in a next preceding image;

the method further comprising two or more communicating steps, each communicating step communicating data between a respective preceding one of the rendering steps and a respective following one of the rendering steps;

each communicating step comprising a substep of storing the respective detail control data of its preceding rendering step in the memory for access during its following rendering step;

each preceding rendering step'"'"'s detail control data including;

respective detail information indicating detail with which to present an image; and

respective maintenance information that the processor can use to determine whether to maintain presentation of images with the indicated detail to avoid oscillation of detail;

the respective following step'"'"'s substep of using the scenes data comprising a substep of using the preceding rendering step'"'"'s detail information in producing the respective image defining data;

the respective following step'"'"'s substep of using the respective rendering speed data comprising a substep of using the preceding rendering step'"'"'s maintenance information in obtaining the respective detail control data;

the sequence of rendering steps together presenting a sequence of images in which display features are perceptible as continuing from a first image of the sequence to a last image of the sequence;

the sequence of images including a subsequence of two or more images during which presentation of images with the same detail is maintained so that oscillation of detail does not occur during the subsequence.

2. The method of claim 1 in which the scenes data include, for each of the scenes, level defining data indicating, for each of a set of levels of detail, a respective rendering of the scene;

each communicating step'"'"'s detail information including respective level identifying data identifying one of the levels of detail.

3. The method of claim 2 in which the subsequence of rendering steps includes first and second consecutive rendering steps and the communicating steps include a first-to-second communicating step that communicates the first rendering step'"'"'s detail control data to the second rendering step;

the second rendering step'"'"'s substep of using the preceding rendering step'"'"'s maintenance information obtaining the second rendering step'"'"'s detail control data so that the first rendering step'"'"'s level identifying data are the same as the second rendering step'"'"'s level identifying data.

4. The method of claim 1 in which each preceding rendering step further comprises a substep of:

using the action data to determine whether the previous rendering step reduced detail;

using the rendering speed data to compare the rendering speed and the threshold speed to determine whether the rendering speed is slower than the threshold speed; and

when the the previous rendering step reduced detail and the rendering speed is not slower than the threshold speed, producing the respective detail control data so that its detail information indicates the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates the rendering speed.

5. The method of claim 4 in which the action data further indicates whether the previous rendering step maintained detail;

each preceding rendering step further comprising a substep of;

obtaining hold speed data indicating a hold speed;

the substep of using the respective rendering speed data further comprising;

when the previous rendering step did not reduce detail or the rendering speed is slower than the threshold speed, using the action data, the hold speed data, and the rendering speed data to determine whether the previous rendering step maintained detail and whether the rendering speed is approximately equal to the hold speed; and

when the previous rendering step maintained detail and the rendering speed is approximately equal to the hold speed, producing the respective detail control data so that its detail information indicates the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates the rendering speed.

6. The method of claim 5 in which the substep of using the respective rendering speed data further comprises:

when the previous rendering step did not reduce detail or the rendering speed is slower than the threshold speed and the previous rendering step did not maintain detail or the rendering speed is not approximately equal to the hold speed, using the rendering speed data to determine whether the rendering speed is slower than the threshold speed; and

when the rendering speed is slower than the threshold speed, producing the respective detail control data so that its detail information indicates less detail than the detail with which the preceding rendering step'"'"'s image is presented;

when the rendering speed is not slower than the threshold speed, producing the respective detail control data so that its detail information indicates more detail than the detail with which the preceding rendering step'"'"'s image is presented.

7. The method of claim 1 in which each preceding rendering step further comprises substeps of:

obtaining detail data indicating detail with which the preceding rendering step'"'"'s image is presented; and

obtaining first hold data indicating detail with which a first previous image was presented and a first previous rendering speed at which the scenes data were used to produce data defining the first previous image;

the substep of using the respective rendering speed data comprising;

using the detail data, the first hold data, and the rendering speed data to determine whether the detail with which the preceding rendering step'"'"'s image is presented is the same as the detail with which the first previous image was presented and whether the first previous rendering speed is approximately the same as the rendering speed; and

when the detail is the same and the speeds are approximately the same, producing the respective detail control data so that its detail information indicates the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates that the detail is maintained.

8. The method of claim 7 in which the rendering speed data and the detail data indicate the rendering speed and the detail with which the preceding rendering step'"'"'s image is presented on a detail/speed scale;

the substep of using the respective rendering speed data further comprising, when the detail is not the same or the speeds are not approximately the same;

using the rendering speed data and the detail data to determine the relation between the rendering speed and the detail with which the preceding rendering step'"'"'s image is presented along the detail/speed scale.

9. The method of claim 8 in which the substep of using the respective rendering speed data further comprises, when the rendering speed is slower than the detail with which the preceding rendering step'"'"'s image is presented along the detail/speed scale:

producing the respective detail control data so that its detail information indicates more detail than the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates that the detail is increased.

10. The method of claim 8 in which the substep of using the respective rendering speed data further comprises, when the rendering speed is faster than the detail with which the preceding rendering step'"'"'s image is presented along the detail/speed scale:

producing the respective detail control data so that its detail information indicates less detail than the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates that the detail is decreased.

11. The method of claim 10 in which the substep of using the respective rendering speed data further comprises, when the rendering speed is faster than the detail with which the preceding rendering step'"'"'s image is presented along the detail/speed scale:

obtaining previous action data indicating whether detail was increased in a second previous image; and

when the previous action data indicates detail was increased, obtaining second hold data indicating detail with which the second previous image was presented and a second previous rendering speed at which the scenes data was used to produce data defining the second previous image.

12. The method of claim 8 in which the substep of using the respective rendering speed data further comprises, when the rendering speed is equal to the detail with which the preceding rendering step'"'"'s image is presented along the detail/speed scale:

producing the respective detail control data so that its detail information indicates the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates that the detail is equal.

13. The method of claim 12 in which the substep of using the respective rendering speed data further comprises, when the rendering speed is equal to the detail with which the preceding rendering step'"'"'s image is presented along the detail/speed scale:

producing second hold data indicating detail with which the preceding rendering step'"'"'s image is presented and the rendering speed.

14. A machine comprising:

a display;

memory;

the memory storing scenes data defining a set of scenes, instruction data indicating instructions, and detail control data for use in controlling image detail to avoid oscillation of detail;

the detail control data including detail information indicating detail with which to present an image on the display and maintenance information for use in determining whether to maintain presentation of images with the indicated detail to avoid oscillation of detail; and

a processor connected for accessing the scenes data, the instruction data, and the detail control data in the memory and also connected for controlling the display to present images;

the instruction data comprising;

rendering instruction data indicating rendering instructions that the processor executes;

the processor, in executing the rendering instructions, performing operations;

that use the scenes data to produce image defining data defining an image;

that control the display to present the image as defined by the image defining data;

that obtain rendering speed data indicating a speed with which the image defining data is produced; and

that compare the rendering speed with a threshold speed above which display features in an image are perceptible as continuations of display features in a next preceding image; and

detail control instruction data indicating detail control instructions that the processor executes;

the processor, in executing the detail control instructions, performing operations that access the detail control data;

to obtain detail data indicating detail with which to present an image;

to obtain maintenance data indicating whether to maintain presentation of images with the indicated detail to avoid oscillation of detail; and

to use the rendering speed data to update the detail control data so that the detail information indicates detail with which to present a subsequent image and the maintenance information can be used in determining whether to maintain presentation of images with the detail indicated after the subsequent image to avoid oscillation of detail;

the processor, in executing the rendering instructions and the detail control instructions, presenting a sequence of images in which display features are perceptible as continuing from a first image of the sequence to a last image of the sequence;

the sequence of images including a subsequence of two or more images during which the processor maintains presentation of images with the same detail so that oscillation of detail does not occur during the subsequence.

15. The machine of claim 14, further comprising a user input device for obtaining user input data indicating signals from a user;

the processor being connected for receiving the user input data;

the instruction data further comprising input receiving instruction data indicating input receiving instructions that the processor executes to perform operations that use the user input data.

16. The machine of claim 14 in which the scenes data comprise level defining data indicating, for a scene, a respective rendering at each of a set of levels of detail;

the detail information including a level data item for indicating one of the set of levels of detail.

17. A method of operating a system that includes:

a display;

memory;

the memory storing scenes data defining a set of scenes; and

a processor connected for accessing the scenes data in the memory and also connected for controlling the display to present images;

the method comprising a sequence of rendering steps, each rendering step comprising substeps of;

using the scenes data to produce respective image defining data defining a respective image;

controlling the display to present the respective image as defined by the respective image defining data;

obtaining respective rendering speed data indicating a speed with which the substep of using the scenes data is performed; and

using the respective rendering speed data to obtain respective detail control data for use in controlling image detail to avoid oscillation of detail;

the method further comprising two or more communicating steps, each communicating step communicating data between a respective preceding one of the rendering steps and a respective following one of the rendering steps;

each communicating step comprising a substep of storing the respective detail control data of its preceding rendering step in the memory for access during its following rendering step;

each preceding rendering step'"'"'s detail control data including respective detail information indicating detail with which to present an image and respective maintenance information that the processor can use to determine whether to maintain presentation of images with the indicated detail to avoid oscillation of detail;

the respective following step'"'"'s substep of using the scenes data comprising a substep of using the preceding rendering step'"'"'s detail information in producing the respective image defining data;

the respective following step'"'"'s substep of using the respective rendering speed data comprising a substep of using the preceding rendering step'"'"'s maintenance information in obtaining the respective detail control data;

each preceding rendering step further comprising a substep of;

obtaining action data indicating whether a previous rendering step reduced detail;

the substep of using the respective rendering speed data comprising;

using the action data and the rendering speed data to determine whether the previous rendering step reduced detail and whether the rendering speed is slower than a threshold speed; and

when the previous rendering step reduced detail and the rendering speed is not slower than the threshold speed, producing the respective detail control data so that its detail information indicates the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates the rendering speed.

18. A method of operating a system that includes:

a display;

memory;

the memory storing scenes data defining a set of scenes; and

a processor connected for accessing the scenes data in the memory and also connected for controlling the display to present images;

the method comprising a sequence of rendering steps, each rendering step comprising substeps of;

using the scenes data to produce respective image defining data defining a respective image;

controlling the display to present the respective image as defined by the respective image defining data;

obtaining respective rendering speed data indicating a speed with which the substep of using the scenes data is performed; and

using the respective rendering speed data to obtain respective detail control data for use in controlling image detail to avoid oscillation of detail;

the method further comprising two or more communicating steps, each communicating step communicating data between a respective preceding one of the rendering steps and a respective following one of the rendering steps;

each communicating step comprising a substep of storing the respective detail control data of its preceding rendering step in the memory for access during its following rendering step;

each preceding rendering step'"'"'s detail control data including;

respective detail information indicating detail with which to present an image; and

respective maintenance information that the processor can use to determine whether to maintain presentation of images with the indicated detail to avoid oscillation of detail;

the respective following step'"'"'s substep of using the scenes data comprising a substep of using the preceding rendering step'"'"'s detail information in producing the respective image defining data;

the respective following step'"'"'s substep of using the respective rendering speed data comprising a substep of using the preceding rendering step'"'"'s maintenance information in obtaining the respective detail control data;

each preceding rendering step further comprising substeps of;

obtaining detail data indicating detail with which the preceding rendering step'"'"'s image is presented; and

obtaining first hold data indicating detail with which a first previous image was presented and a first previous rendering speed at which the scenes data were used to produce data defining the first previous image;

the substep of using the respective rendering speed data comprising;

using the detail data, the first hold data, and the rendering speed data to determine whether the detail with which the preceding rendering step'"'"'s image is presented is the same as the detail with which the first previous image was presented and whether the first previous rendering speed is approximately the same as the rendering speed; and

when the detail is the same and the speeds are approximately the same, producing the respective detail control data so that its detail information indicates the detail with which the preceding rendering step'"'"'s image is presented and so that its maintenance information indicates that the detail is maintained to avoid oscillation of detail.