System and method for reducing latency in display of computer-generated graphics

• US 20060044289A1
• Filed: 06/21/2004
• Published: 03/02/2006
• Est. Priority Date: 06/21/2004
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Yee, Dawson L.
• Granted Patent: US 7,259,758 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2370/04 Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor

Abstract

An interactive display system wherein a projector receives signals from a graphics source in a manner that reduces latency in images projected onto a display surface. The signals include a pixel clock signal, pixel attribute signals, and synchronization signals. The pixel clock signal is used to clock sample and hold registers at the projector to preserve the pixel attribute signals received from the graphics source. The preserved pixel attribute signals, along with position signals corresponding to the synchronization signals, are presented directly to the projector. Parameters of the projector are known, and all gain, gamma correction, and scaling are performed before the signals are provided by the graphics source. Thus, it is unnecessary to digitize, store, adjust, or otherwise process pixel attribute signals at the projector, which simplifies processing of the graphics signals and reduces latency in generating the image in response to an input on the display surface.

Claims

1. A system for reducing a processing delay of a graphics display that presents a graphics image in response to graphics image data received from a graphics source, comprising:

(a) a pixel clock signal input configured to receive a pixel clock signal from the graphics source, each of a series of pulses comprising the pixel clock signal indicating a transition to a next pixel in the graphics image data;

(b) a pixel input configured to receive a plurality of attribute signals from the graphics source, each of the attribute signals representing a desired visual attribute of a pixel;

(c) a synchronization input configured to receive a plurality of synchronization signals from the graphics source, each of the synchronization signals representing a transition to a next portion of the graphics image data;

(d) a capture buffer configured to receive the pixel clock signal from the pixel clock signal input and to receive the attribute signals from the pixel input, the capture buffer being further configured, upon receiving each pulse of the pixel clock signal, to preserve values of the attribute signals just currently being received, until receiving a next pulse of the pixel clock signal;

(e) a pixel clock output configured to receive the pixel clock signal from the pixel clock signal input and to communicate the pixel clock signal to the graphics display, to indicate a transition to a next pixel;

(f) a pixel output configured to receive the values of the attribute signals preserved by the capture buffer and to communicate the values of the attribute signals to the graphics display; and

(g) a synchronization output configured to receive the synchronization signals from the synchronization input and provide position signals to the graphics display, the position signals communicating a transition to a next pixel position on the graphics display corresponding to a next portion of the graphics image.

2. The system of claim 1, wherein the pixel clock signal received by the pixel clock signal input includes a graphics source pixel clock signal, the graphics source pixel clock signal being used at the graphics source, to cause the graphics source to generate the plurality of attribute signals from a next set of pixel attributes stored in a memory of the graphics source.

3. The system of claim 1, wherein the plurality of attribute signals received from the graphics source includes a plurality of color component signals, each of the color component signals indicating a level of a different color content for presenting the pixel in the graphics image on the graphics display.

4. The system of claim 3, wherein the plurality of color component signals includes a red component signal, a green component signal, and a blue component signal.

5. The system of claim 1, wherein the plurality of synchronization signals received from the graphics source include at least one of a horizontal synchronization signal, and a vertical synchronization signal, the horizontal synchronization signal being configured to signal a transition to a next line of the graphics image, the vertical synchronization signal being configured to signal a transition to a next frame of the graphics image data.

6. The system of claim 5, wherein the synchronization output includes at least one of an end of line signal and an end of frame signal, the end of line signal signifying a transition to a next line on the graphics display corresponding to the transition to the next line of the graphics image included in the horizontal synchronization signal, and the end of frame signal signifying a transition to an origination point on the graphics display corresponding to the transition to the next frame of the graphics image data.

7. The system of claim 1, wherein each of the plurality of attribute signals includes an analog signal, and wherein the capture buffer includes a sample and hold circuit.

8. The system of claim 1, wherein each of the plurality of attribute signals includes a digital signal, and wherein the capture buffer includes a latch, the latch being configured to preserve a maximum expected number of data bits provided in the digital signal.

9. The system of claim 1, wherein the values of the attribute signals preserved by the capture buffer and communicated to the graphics display maintain at least one of a same gain level and a same gamma level as the plurality of attribute signals received from the graphics source.

10. The system of claim 1, wherein the synchronization output includes at least one of an end of line signal and an end of frame signal.

11. The system of claim 1, wherein the graphics source includes a video graphics array adapter.

12. The system of claim 1, wherein the graphics display is configured to present the graphics image data on the graphics display at a same resolution as the graphics image data received from the graphics source.

13. The system of claim 1, wherein the graphics display includes a digital projector.

14. A system for reducing a processing delay of a graphics display that presents a graphics image in response to graphics image data received from a graphics source, comprising:

(a) a pixel clock signal input configured to receive a pixel clock signal from the graphics source, each of a series of pulses comprising the pixel clock signal indicating a transition to a next pixel in a line of the graphics image and causing the graphics source to generate a plurality of color component signals from a next set of pixel attributes stored in a memory of the graphics source;

(b) a pixel input configured to receive the plurality of color component signals, each of the plurality of color component signals representing a desired level of a different color in the pixel signals received from the graphics source;

(c) a synchronization input configured to receive a horizontal synchronization signal, the horizontal synchronization signal being configured to indicate a transition to a next line of the graphics image, and a vertical synchronization signal, the vertical synchronization signal being configured to indicate a transition to a next frame of the graphics image data;

(d) a capture buffer configured to receive the pixel clock signal from the pixel clock signal input and to receive the color component signals from the pixel input, the capture buffer being further configured, upon receiving each pulse of the pixel clock signal, to preserve values of the color component signals currently being received, until receiving a next pulse of the pixel clock signal;

(e) a pixel clock output configured to receive the pixel clock signal from the pixel clock signal input and to communicate the pixel clock signal to the graphics display to indicate a transition to a next pixel of the graphics image;

(f) a pixel output configured to receive the values of the color component signals preserved by the capture buffer and to communicate the values of the color component signals to the graphics display; and

(g) a synchronization output configured to receive the horizontal synchronization signal and to generate a corresponding end of line signal signifying a transition to a next line of the graphics image, and further configured to receive the vertical synchronization signal from the synchronization input and generate a corresponding end of frame signal signifying a transition to an origination point on the graphics display corresponding to the transition to the next frame of the graphics image data, the synchronization output being further configured to generate the end of line signal and the end of frame signal to preserve the scaling of the graphics image data received from the graphics source.

15. The system of claim 14, wherein the plurality of color component signals includes a red component signal, a green component signal, and a blue component signal.

16. The system of claim 14, wherein each of the plurality of attribute signals includes an analog signal, and wherein the capture buffer includes a sample and hold circuit.

17. The system of claim 14, wherein each of the plurality of attribute signals includes a digital signal, and wherein the capture buffer includes a latch, the latch being configured to preserve a maximum expected number of data bits provided in the digital signal.

18. The system of claim 14, wherein the values of the color component signals preserved by the capture buffer and communicated to the graphics display maintain at least one of a same gain level and a same gamma level as the plurality of color component signals received from the graphics source.

19. The system of claim 14, wherein the graphics source includes a video graphics array adapter.

20. The system of claim 14, wherein the graphics display includes a digital projector.

21. A system for generating a graphics image presented on a display in response to user interaction with the display, without causing an excessive latency in the response, comprising:

(a) an interactive display including;

(i) a projector;

(ii) a display surface that diffuses light and on which an image can be displayed by the projector, said display surface having a processing side and an interactive side, the processing side being opposite to the interactive side from which the image is viewed and adjacent to which physical objects can be placed;

(iii) a light source disposed on the processing side of the display surface, the light source emitting infrared light that is transmitted through the display surface to the interactive side; and

(iv) a light sensor disposed on the processing side of the display surface, the light sensor sensing infrared light reflected back from a physical object that is adjacent to the processing side of the display surface through the display surface;

(b) a processor in communication with the light sensor;

(c) a memory in communication with the processor, the memory storing data and machine instructions that cause the processor to carry out a plurality of functions;

(d) a graphics adapter in communication with the processor and configured to generate graphics image data the define lines of a graphics image to be projected by the projector onto the display surface; and

(e) a projector control system in communication with the graphics adaptor, for controlling the projector to display the graphics image data generated by the graphics adapter, the projector control system comprising;

(i) a pixel clock signal input configured to receive a pixel clock signal from the graphics adapter, each of a series of pulses of the pixel clock signal indicating a transition to a next pixel in a line of the graphics image;

(ii) a pixel input configured to receive a plurality of attribute signals from the graphics adapter, each of the attribute signals representing a desired visual attribute of a pixel;

(iii) a synchronization input configured to receive a plurality of synchronization signals from the graphics adapter, each of the synchronization signals representing a transition to a next portion of the graphics image data;

(iv) a capture buffer configured to receive the pixel clock signal from the pixel clock signal input and to receive the attribute signals from the pixel input, the capture buffer being further configured, upon receiving each pulse of the pixel clock signal, to preserve values of the attribute signals currently being received, until receiving a next pulse of the pixel clock signal;

(v) a pixel clock output configured to receive the pixel clock signal from the pixel clock signal input and to communicate the pixel clock signal to the projector;

(vi) a pixel output configured to receive the values of the attribute signals preserved by the capture buffer and to communicate the values of the attribute signals to the projector; and

(vii) a synchronization output configured to receive the synchronization signals from the synchronization input and to provide position signals to the projector, the position signals communicating a transition to a next position on the display surface corresponding to a next portion of the graphics image data.

22. The system of claim 21, wherein the pixel clock signal received by the pixel clock signal input includes a graphics adapter pixel clock signal, the graphics adapter pixel clock signal causing the graphics adapter to generate the plurality of attribute signals from a next set of pixel attributes stored in a memory of the graphics adapter.

23. The system of claim 21, wherein the plurality of attribute signals received from the graphics adapter includes a plurality of color component signals, each of the color component signals representing a desired level for a different color content of the pixel.

24. The system of claim 23, wherein the plurality of color component signals includes a red component signal, a green component signal, and a blue component signal.

25. The system of claim 21, wherein the plurality of synchronization signals received from the graphics adapter includes at least one of a horizontal synchronization signal, and a vertical synchronization signal, the horizontal synchronization signal being configured to signal a transition to a next line of the graphics image, and the vertical synchronization signal being configured to signal a transition to a next frame of the graphics image data.

26. The system of claim 21, wherein the synchronization output includes at least one of an end of line signal, and an end of frame signal, the end of line signal signifying a transition to a next line of the graphics image in the graphics image data and being included in the horizontal synchronization signal, and the end of frame signal signifying a transition to an origination point on the display surface corresponding to the transition to the next frame of the graphics image data.

27. The system of claim 21, wherein each of the plurality of attribute signals includes an analog signal, and wherein the capture buffer includes a sample and hold circuit.

28. The system of claim 21, wherein each of the plurality of attribute signals includes a digital signal, and wherein the capture buffer includes a latch, the latch being configured to preserve a maximum expected number of data bits provided in the digital signal.

29. The system of claim 21, wherein the values of the attribute signals preserved by the capture buffer and communicated to the projector maintain at least one of a same gain level and a same gamma level as the plurality of attribute signals received from the graphics source.

30. The system of claim 21, wherein the synchronization output includes at least one of an end of line signal and an end of frame signal.

31. The system of claim 21, wherein the graphics adapter comprises a video graphics array adapter.

32. The system of claim 21, wherein the projector is configured to present the graphics image on the display surface at a same resolution as the graphics image data received from the graphics adapter.

33. The system of claim 21, wherein the projector comprises one of a liquid crystal display device, a digital light processor device, and a liquid crystal on silicon device.

34. A method for reducing latency in presenting a graphics image on a graphics display, said graphics image corresponding to graphics image data received from a graphics source, comprising the steps of:

(a) receiving a pixel clock signal from the graphics source, each of a series of pulses of the pixel clock signal indicating a transition to a next pixel in a line of the graphics image;

(b) receiving a plurality of attribute signals from the graphics source, each of the attribute signals representing a desired visual attribute of a pixel;

(c) receiving a plurality of synchronization signals from the graphics source, each of the synchronization signals representing a transition to a next portion of the graphics image data;

(d) preserving values of the attribute signals currently being received upon receiving each pulse of the pixel clock signal, until receiving a next pulse of the pixel clock signal;

(e) communicating the pixel clock signal to the graphics display to indicate a transition to a next pixel in a line of the graphics image;

(f) communicating the values of the attribute signals to the graphics display; and

(g) generating a plurality of position signals conveyed to the graphics display, the position signals corresponding to the synchronization signals and communicating a transition to a next position of the graphics display corresponding to a next portion of the graphics image data.

35. The method of claim 34, wherein the pixel clock signal received from the graphics source includes the graphics source pixel clock signal, the graphics source pixel clock signal causing the graphics source to generate the plurality of attribute signals from a next set of pixel attributes stored in a memory of the graphics source.

36. The method of claim 34, wherein the plurality of attribute signals received from the graphics source includes a plurality of color component signals, each of the color component signals representing a desired level for a different color content of the pixel.

37. The method of claim 36, wherein the plurality of color component signals includes a red component signal, a green component signal, and a blue component signal.

38. The method of claim 34, wherein the plurality of synchronization signals received from the graphics source include at least one of a horizontal synchronization signal, the horizontal synchronization signal being configured to signal a transition to a next line of the graphics image data, and a vertical synchronization signal, the vertical synchronization signal being configured to signal a transition to a next frame of the graphics image data.

39. The method of claim 34, wherein the synchronization output includes at least one of an end of line signal, and an end of frame signal, the end of line signal signifying a transition to a next line of the graphics image corresponding to the transition to the next line of the graphics image data included in the horizontal synchronization signal, the end of frame signal signifying a transition to an origination point on the graphics display corresponding to the transition to the next frame of the graphics image data.

40. The method of claim 34, wherein each of the plurality of attribute signals includes an analog signal, and wherein the capture buffer includes a sample and hold circuit.

41. The method of claim 34, wherein each of the plurality of attribute signals includes a digital signal, and wherein the capture buffer includes a latch, the latch being configured to preserve a maximum expected number of data bits provided in the digital signal.

42. The method of claim 34, wherein the values of the attribute signals preserved by the capture buffer and communicated to the graphics display maintain at least one of a same gain level and a same gamma level, as the plurality of attribute signals received from the graphics source.

43. The method of claim 34, wherein the synchronization output includes at least one of an end of line signal and an end of frame signal.

44. The method of claim 34, wherein the graphics source includes a video graphics array adapter.

45. The method of claim 34, wherein the graphics display is configured to present the graphics image data at a same resolution as the graphics image data received from the graphics source.

46. The method of claim 34, wherein the graphics display comprises a projector.

47. A method for directing a graphics display to present graphics images corresponding to graphics image data received from a graphics source, so as to reduce a processing delay in presenting the graphics images on the graphics display, comprising the steps of:

(a) receiving a pixel clock signal from the graphics source, each of a series of pulses of the pixel clock signal indicating a transition to a next pixel in a line of the graphics image and causing the graphics source to generate a plurality of color component signals from a next set of pixel attributes stored in a memory of the graphics source;

(b) receiving the plurality of color component signals, each of the color component signals representing a desired constituent color content of the pixel signals from the graphics source;

(c) receiving a horizontal synchronization signal, the horizontal synchronization signal being configured to signal a transition to a next line of the graphics image;

(d) receiving a vertical synchronization signal, the vertical synchronization signal being configured to signal a transition to a next frame of the graphics image data;

(e) preserving values of the color component signals currently being received upon receiving each pulse of the pixel clock signal, until receiving a next pulse of the pixel clock signal;

(f) communicating the pixel clock signal to the graphics display;

(g) communicating the values of the color component signals to the graphics display;

(h) generating an end of line signal corresponding to the horizontal synchronization signal, the end of line signal signifying a transition to a next line of the graphics image;

(i) generating an end of frame signal corresponding to the vertical synchronization signal, the end of frame signal signifying a transition to an origination point on the graphics display; and

(j) presenting the graphics image on the graphics display, wherein a resolution of the graphics display is the same as that of the graphics image data received from the graphics source.

48. The method of claim 47, wherein the plurality of color component signals includes a red component signal, a green component signal, and a blue component signal.

49. The method of claim 47, wherein each of the plurality of attribute signals includes an analog signal, and wherein the capture buffer includes a sample and hold circuit.

50. The method of claim 47, wherein each of the plurality of attribute signals includes a digital signal, and wherein the capture buffer includes a latch, the latch being configured to preserve a maximum expected number of data bits provided in the digital signal.

51. The method of claim 47, wherein the values of the color component signals preserved by the capture buffer and communicated to the graphics display maintain at least one of a same gain level and a same gamma level as the plurality of color component signals received from the graphics source.

52. The method of claim 47, wherein the graphics source includes a video graphics array adapter.

53. The method of claim 47, wherein the graphics display comprises an image projector.