Graphic input apparatus

• US 4,561,017 A
• Filed: 08/19/1983
• Issued: 12/24/1985
• Est. Priority Date: 08/19/1983
• Status: Expired due to Term

• Current Assignee: Richard Greene
• Original Assignee: Richard Greene
• Inventors: Greene, Richard
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US06/524,534
• Time in Patent Office: 858 Days
• Field of Search: 358/93, 358/217, 358/215, 358/226, 358/242, 358/250, 358/81
• US Class Current: 348/707
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• 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
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour

Abstract

A computer graphic input device is disclosed for imaging the points of contact between objects and a surface. The input device is defined by a transparent material with one surface thereof defining a drawing surface. The index of refraction of the material is greater than the index of refraction of the medium on the upper side of the drawing surface. In the preferred embodiment, the transparent material is prism shaped in configuration. A camera is mounted on the lower side of the drawing surface in a manner to only capture light rays which have been totally internally reflected from the drawing surface. By this arrangement, objects located on the upper side of the drawing surface will be imaged by the camera only when and where the object is in direct contact with the drawing surface. The size and shape of the input pattern is digitized, processed and displayed on a monitor. The subject apparatus can be used to produce graphic effects achieved by various natural drawing implements, such as a brush.

Claims

1. A graphical input device comprising:

a transparent material with one surface thereof defining a drawing surface, with the index of refraction of the material being greater than the index of refraction of the medium on one side of the drawing surface;

light absorbing means located on the other side of said drawing surface;

camera means located on said other side of said drawing surface and in a manner to only capture light rays which originate from said light absorbing means and which have been totally internally reflected from said drawing surface whereby lighted objects placed on said drawing surface will be imaged by said cameral means only when said objects are in direct contact with said one side of said drawing surface, with the remaining field being dark due to said light absorbing means.

2. A graphical input device as recited in claim 1 further including a liquid layer covering said drawing surface, said liquid having an index of refraction greater than the surrounding medium such that said liquid layer functions to define an effective drawing surface to facilitate the imaging of objects.

3. A graphical input device as recited in claim 1 wherein said transparent material has at least three faced, with a first face defining the drawing surface, and wherein a darkened second face defines said light absorbing means and wherein said camera means is located to receive light through a third face.

4. A graphical input device as recited in claim 3 further including a means for illuminating objects to be imaged, said illumination means being directed into the transparent material through a face other than said third face.

5. A graphical input device as recited in claim 1 further including a means for correcting horizontal distortion created by said camera means.

6. A graphical input device as recited in claim 5 wherein said correcting means is defined by a means for modulating the horizontal deflection of the scanning beam of said camera means in proportion to the degree of vertical deflection.

7. A graphical input device comprising:

a transparent material having at least four faces and a prismatic configuration, with a first face defining a drawing surface and a second face being parallel to the first, with the index of refraction of the material being greater than the index of refraction of the medium on one side of the drawing surface;

camera means located in a manner to only capture light rays which have been totally internally reflected from said drawing surface such that an object will be imaged only when said object is in contact with said one side of the drawing surface; and

a video monitor for displaying images captured by said camera means, said monitor being located adjacent said second surface to permit the viewing of objects imaged by said camera means and displayed by said video monitor through the drawing surface.

8. A graphical input device as recited in claim 7 further including a liquid layer covering said drawing surface, said liquid having an index of refraction greater than the surrounding medium such that said liquid layer functions to define an effective drawing surface to facilitate the imaging of objects.

9. A graphical input device as recited in claim 7 wherein said video monitor displays imaged objects in white on a dark background.

10. A graphical input device as recited in claim 7 wherein said video monitor displays imaged objects in black on a light background.

11. A graphical input device as recited in claim 7 further including a means for correcting horizontal distortion created by said camera means.

12. A graphical input device as recited in claim 11 wherein said correcting means is defined by a means for modulating the horizontal deflection of the scanning beam of said camera means in proportion to the degree of vertical deflection.