Wireless user-interface arrangement and method

• US 6,677,987 B1
• Filed: 12/03/1997
• Issued: 01/13/2004
• Est. Priority Date: 12/03/1997
• Status: Expired due to Term

• Current Assignee: 8X8, Inc.
• Original Assignee: 8X8, Inc.
• Inventors: Girod, Bernd
• Primary Examiner(s): Lee, Young
• Assistant Examiner(s): VO, TUNG T
• Application Number:
  US08/984,602
• Time in Patent Office: 2,232 Days
• Field of Search: H04/N.5225, 348/2, 348/141, 348/3, 348/142, 348/5, 348/15, 348/169-173, 348/13, 348/136, 348/135, 348/137, 348/116, 345/158, 345/157, 345/172, 345/156, 345/169, 364/188, 341/22, 382/151, 382/103
• US Class Current: 348/171
• CPC Class Codes: G06F 3/0386 for light pen

Abstract

A wireless user-interface method and arrangement having a light source and a circuit arrangement that detects the presence and position of the light source. A light source emits modulated light having a first modulation frequency that is captured by a camera circuit arrangement. A circuit arrangement uses relative pixel luminances and differences in pixel luminances between frames to detect the presence of modulated light from the light source. The position of the light source is tracked from frame to frame and the position information is output for use by application software or circuitry to direct movement of a pointer in a computer display, for example. Modulated light having a second modulation frequency from the light source is detected by the circuit arrangement and interpreted as selection of a control function, which is provided as output to application software or circuitry. The application uses the position of the light source along with control signals to identify an operation to perform.

Claims

1. A method for tracking within frames of digital video data movement of a light source that emits light modulated different from a frequency of the frames of digital video data, comprising the steps of:

determining presence of the light as a function of relative luminances of portions of a frame of digital video data and difference luminances between the portions of the frame and corresponding portions of a previous frame;

storing coordinates and associated codes for selected portions of the frame, the codes indicative of relative luminances and difference luminances of the selected portions, and the selected portions having the greatest relative luminances and difference luminances; and

determining a position of the light within a frame as a function of the relative luminances, the difference luminances, and coordinates and associated codes of the selected portions of the frame relative to coordinates and associated codes of selected portions of the previous frame.

4. The method of claim 1, wherein determining the presence of light includes receiving the modulated light along with video images.

5. The method of claim 1, wherein determining the presence of light includes receiving the modulated light along with video images and further including, after receiving the modulated light, decoding the light using a digital video decoder.

6. The method of claim 5, wherein the digital video decoder uses a video processor programmed to compare successive frames of video images and discern between modulated light and light from other sources.

7. The method of claim 1, further including comparing successive frames of video images and discerning between modulated light and light from other sources.

8. The method of claim 7, wherein the modulated light is modulated at a pseudo-random frequency.

9. The method of claim 7, wherein the modulated light is modulated at a constant frequency.

2. An apparatus for tracking within frames of digital video data movement of a light source that emits light modulated different from a frequency of the frames of digital video data, comprising:

means for determining presence of the light as a function of relative luminances of portions of a frame of digital video data and difference luminances between the portions of the frame and corresponding portions of a previous frame;

means for storing coordinates and associated peak codes for selected portions of the frame, the peak codes indicative of relative luminances and difference luminances of the selected portions, and the selected portions having the greatest relative luminances and difference luminances; and

means for determining a position of the light within a frame as a function of the relative luminances, the difference luminances, and coordinates and associated peak codes of the selected portions of the frame relative to coordinates and associated peak codes of selected portions of the previous frame.

3. A user interface circuit arrangement comprising:

a camera configured and arranged to provide digital video images;

a first detection circuit coupled to the camera and configured and arranged to detect a presence of modulated light having a first modulation frequency represented in the digital video images and generate a first signal in response to the presence of the modulated light;

a tracking circuit coupled to the detection circuit and to the camera and configured and arranged to detect movement of the modulated light represented in the digital video images in response to the first signal from the detection circuit; and

a second detection circuit coupled to the first detection circuit and configured and arranged to detect modulated light having a second modulation frequency represented in the digital video images and generate a second signal in response to the presence of the modulated light having the second modulation frequency and the first signal.

10. The arrangement of claim 3, wherein at least one of the first detection circuit, the tracking circuit and the second detection circuit includes a digital video decoder.

11. The arrangement of claim 10, wherein the digital video decoder includes a computer programmed to compare successive frames of video images.

12. The arrangement of claim 11, wherein the modulated light is modulated at a pseudo-random frequency.

13. The arrangement of claim 11, wherein the modulated light is modulated at a constant frequency.

14. The arrangement of claim 11, wherein the computer is further programmed to discern between modulated light and light from other sources.

15. The arrangement of claim 10, wherein the digital video decoder is adapted to discern between modulated light and light from other sources.

16. A method for tracking within frames of digital video data movement of a light source that emits light modulated different from a frequency of the frames of digital video data, comprising the steps of:

determining presence of the modulated light as a function of relative luminances of portions of a frame of digital video data and difference luminances between the portions of the frame and corresponding portions of a previous frame; and

determining a position of the light within a frame as a function of the relative luminances and the difference luminances relative to coordinates of selected portions of the previous frame.

17. An apparatus for tracking within frames of digital video data movement of a light source that emits light modulated different from a frequency of the frames of digital video data, comprising:

means for determining presence of the modulated light as a function of relative luminances of portions of a frame of digital video data and difference luminances between the portions of the frame and corresponding portions of a previous frame; and

means for determining a position of the light within a frame as a function of the relative luminances and the difference luminances relative to coordinates of selected portions of the previous frame.