Collaborative pointing devices

• US 20040239653A1
• Filed: 05/27/2003
• Published: 12/02/2004
• Est. Priority Date: 05/27/2003
• Status: Active Grant

• Current Assignee: York University
• Original Assignee: York University
• Inventors: Stuerzlinger, Wolfgang
• Granted Patent: US 7,193,608 B2
• Time in Patent Office: Days
• US Class Current: 345/183
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06F 3/0386 for light pen

Abstract

A method and system for determining a position of laser spots in an initial image due to a plurality of laser pointer, the method having the steps of acquiring a sequence of images from a camera directed at the initial image to produce acquired images thereof, each said acquired image comprising image elements forming a frame; assigning each of said laser pointers a unique transmission pattern; registering said code of each of said laser pointers during frame i with a processor; determining said laser spots in said frame i; registering the appearance of the laser spots of each of the laser pointers during frame i with a processor; assigning positional coordinates to each said located laser spots so as to produce a sequence of positional coordinates (x_i,y_i) corresponding to sequential positions of the laser spot in the initial image; whereby said laser spots appear in the captured images in a pattern corresponding to said unique transmission pattern and each of said laser pointers is uniquely identifiable and tracked.

Claims

1. A system for collaborating between a plurality of users, each user having a laser input device for interacting with an initial image, said system having:

a controller for controlling operation of said laser input devices and registering interactions by said users via said laser input devices;

an initial image provider for providing said initial image on said display;

a camera for capturing successive images to form a sequence of captured images thereof;

for processing and mapping said captured image to said initial image;

said captured image having a plurality of picture elements;

each of said laser input devices caused by said controller to transmit a modulated laser beam of a distinct pattern, said laser beam producing a laser spot on said initial image;

a processor for analyzing said captured sequence of images to determine the presence of said laser spots, said laser spots appearing in said sequence of captured images in accordance with said distinct pattern;

whereby said processor determines a relationship between each pixel in said captured images and the corresponding pixel on said initial images and determines interactions on said display associated with each of said laser input devices, such that laser spots of each of said laser input devices are uniquely identified by recognition of said distinct pattern, said processor examining successive images and identifying respective laser input devices from recognition of said distinct patterns in said images.

2. The system of claim 1 wherein said processor is a computer having a computer-readable medium including an application program to provide instructions to said initial image provider, display and controller, and for processing said captured images.

3. The system of claim 2 wherein said processor assigns positional coordinates to each said laser spots so as to produce a sequence of positional coordinates (x_i,y_i) corresponding to sequential positions of said laser spot in said initial image.

4. The system of claim 3 wherein said each captured image is analyzed to predict a position of said laser spots when said laser spot due to a particular laser input device is missing.

5. The system of claim 1 wherein said laser input devices are coupled to said controller via wireless means.

6. The system of claim 1 wherein said laser spot includes picture elements having a brightness exceeding a predetermined threshold in said captured image.

7. The system of claim 1 wherein said distinct pattern includes pulsed power of predetermined frequency.

8. The system of claim 7 wherein said distinct pattern includes a binary or Gray code pattern.

9. The system of claim 1 wherein said laser input devices include an actuator to initiate said transmission of said laser beam as a means of said interaction.

10. The system of claim 1 wherein said laser beam is eye-safe.

11. The system of claim 10 wherein said laser beam is a Class IIIA laser.

12. The system of claim 10 wherein said controller causes said laser beam to be emitted for less than 0.25 seconds.

13. The system of claim 7 wherein if said laser spot is not detected in a predetermined number of successive captured images said laser beam is turned off by said controller thereby preventing eye damage by said laser beam.

14. The system of claim 13 wherein said predetermined number of successive captured images is nine when said predetermined frequency is 60 Hz.

15. A method determining a position of a laser spot on an initial image due to a plurality of laser pointers, the method having the steps of:

acquiring a sequence of images from a camera directed at the initial image to produce captured images thereof, each of said captured images comprising image elements forming a frame;

assigning each of said laser pointers a unique transmission pattern;

registering said appearance of said laser spots of each of said laser pointers during frame i with a processor;

registering said appearance of said laser spots of each of said laser pointers during frame i+1 with said processor;

assigning positional coordinates to each of said located laser spots so as to produce a sequence of positional coordinates (x_i,y_i) corresponding to sequential positions of the laser spot in the initial presentation image;

predicting a location of said laser spot in said frame i based on positional coordinates (x_i,y_i) of lasers spots located in preceding frame i−

1;

determining which of said laser input devices was transmitting during said frame i by designating a laser spot closest to a predicted location as current position or using predicted location as current position; and

reporting said location of said laser spot in frame i,

whereby said laser spots appear in said captured images in a pattern corresponding to said unique transmission pattern and each of said laser pointers is uniquely identifiable and tracked.

16. The method of claim 15 wherein said laser pointers are caused to transmit for less than 0.25 seconds, thus making the laser pointers eye-safe.

17. The method of claim 15 wherein if said laser spot is not detected in a predetermined number of successive captured images, the laser beam is turned off thereby preventing eye damage.

18. The system of claim 17 wherein said predetermined number of successive captured images is nine frames when said unique transmission pattern has a frequency of 60 Hz.