Projector and camera arrangement with shared optics and optical marker for use with whiteboard systems

• US 20050162409A1
• Filed: 03/15/2005
• Published: 07/28/2005
• Est. Priority Date: 08/18/2000
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shae, Zon-Yin, Wang, Xiping, Tseng, Belle L., Hendriks, Ferdinand
• Granted Patent: US 7,355,584 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/03542 Light pens for emitting or receiving light
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386

Abstract

Projector and camera arrangements are provided for use in electronic whiteboard systems. Specifically, the present invention provides projector and camera arrangements wherein the projector and camera share the same imaging optics. By sharing the same projection and camera optics, the distortions that affect the projection system are the same as those of the camera system. Thus, the calibration step required in conventional whiteboard systems where the projector and camera are separate, i.e., each having their own distinct optics and settings, is no longer needed. Further, the arrangements provided in accordance with the invention are self-aligning, even when lens distortions are large and even in the presence of strong perspective effects. The shared optics projector and camera arrangements of the invention also provide for dynamic zooming. In addition, various active and passive optical marker or lightpen designs are provided for use in electronic whiteboard systems.

Claims

1. A passive optical marker system for use in accordance with an electronic whiteboard system, the electronic whiteboard system including a data entry surface, an image capture device and an image projection device, the passive optical marker system comprising:

an infrared-emitting light source for illuminating the data entry surface; and

an infrared light reflector having a low-friction glide and a non-isotropic surface, the reflector being worn by a user such that the low-friction glide comes into contact with the surface when the user enters data and, in accordance with such data entry, infrared light emitted by the source is reflected from the reflector to the image capture device, such that the image capture device can capture the reflected infrared light and track a position of the reflector, and such that the image projection device can project an image which is viewable on the surface, in proximity of the position of the reflector, and representative of the data entered in accordance with the reflector on the surface.

2. The system of claim 1, wherein the non-isotropic surface of the reflector is unique as compared to other reflectors.

3. The system of claim 1, wherein the infrared light reflector is worn over a tip of an index finger of a user.

4. The system of claim 1, wherein the infrared light reflector reflects the infrared light diffusely such that an orientation of the infrared light reflector does not significantly affect a reflected signal strength.

5. The system of claim 1, wherein the data entry surface is not reflective.