Coordinate input apparatus, control method therefor and computer-readable memory

• US 6,795,061 B2
• Filed: 08/01/2001
• Issued: 09/21/2004
• Est. Priority Date: 08/07/2000
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): FATAHI YAR, MAHMOUD
• Application Number:
  US09/918,461
• Publication Number:
  US 20020075386A1
• Time in Patent Office: 1,147 Days
• Field of Search: 345/157, 345/158, 345/175, 345/182, 353/122
• US Class Current: 345/175
• 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

The outputs from a coordinate detector obtained by irradiating a plurality of predetermined positions on a coordinate input screen are stored in correspondence with each position of the coordinate input screen for a projection display section. The position of the coordinate input screen is designated by a switch. On the basis of output information from the coordinate detector, which corresponds to the designated position, the coordinate values of a light spot on the coordinate input screen are calculated by a coordinate calculation section.

Claims

1. A coordinate input apparatus which detects light from a pointing device, with which a coordinate input screen is irradiated, by a coordinate detector, thereby generating a coordinate output signal corresponding to a position on the coordinate input screen, which is irradiated with the light, comprising:

storage means for storing a plurality of coordinate values corresponding to outputs from the coordinate detector which are obtained by irradiating a predetermined position on each of a plurality of coordinate input screens with the light, wherein each of the plurality of coordinate input screens is set at different set positions against a direction along an optical axis between the coordinate input screen and the coordinate detector;

selection means for selecting a predetermined coordinate input screen from said plurality of coordinate input screens and for selecting coordinate values from the plurality of coordinate values stored by said storage means, which correspond to said predetermined coordinate input screen selected from said plurality of coordinate input screens; and

arithmetic means for calculating the position on the predetermined coordinate input screen selected from said plurality of coordinate input screens, which is irradiated with the light, on the basis of the selected coordinate values.

2. The apparatus according to claim 1, wherein said arithmetic means determines an origin on the coordinate input screen on the basis of the outputs from the coordinate detector which are obtained by irradiating the predetermined position on each of the plurality of coordinate input screens with the light.

3. The apparatus according to claim 1, wherein said arithmetic means determines a magnification to be used to calculate the coordinate values on the coordinate input screen on the basis of the outputs from the coordinate detector which are obtained by irradiating the predetermined position on each of the plurality of coordinate input screens with the light.

4. The apparatus according to claim 1, wherein said arithmetic means determines a fixed input point on the coordinate input screen on the basis of the outputs from the coordinate detector which are obtained by irradiating the predetermined position on each of the plurality of coordinate input screens with the light.

5. A control method for a coordinate input apparatus which detects light from a pointing device, with which a coordinate input screen is irradiated, by a coordinate detector, thereby generating a coordinate output signal corresponding to a position on the coordinate input screen, which is irradiated with the light, comprising:

a storage step of storing a plurality of coordinate values corresponding to outputs from the coordinate detector which are obtained by irradiating a predetermined position on each of a plurality of coordinate input screens with the light, wherein each of the plurality of coordinate input screens is set at different set positions against a direction along an optical axis between the coordinate input screen and the coordinate detector;

a selection step of selecting a predetermined coordinate input screen from the plurality of coordinate input screens and for selecting coordinate values from the plurality of coordinate values stored in the storage step, which corresponds to the predetermined coordinate input screen selected from the plurality of coordinate input screens; and

an arithmetic step of calculating the position on the predetermined coordinate input screen selected from the plurality of coordinate input screens, which is irradiated with the light, on the basis of the coordinate values selected in the selection step.

6. The method according to claim 5, wherein in the arithmetic step, an origin on the coordinate input screen is determined on the basis of the outputs from the coordinate detector which are obtained by irradiating the predetermined position on each of the plurality of coordinate input screens with the light.

7. The method according to claim 5, wherein in the arithmetic step, a magnification to be used to calculate the coordinate values on the coordinate input screen is determined on the basis of the outputs from the coordinate detector which are obtained by irradiating the predetermined position on each of the plurality of coordinate input screens with the light.

8. The method according to claim 5, wherein in the arithmetic step, a fixed input point on the coordinate input screen is determined on the basis of the outputs from the coordinate detector which are obtained by irradiating the predetermined position on each of the plurality of coordinate input screens with the light.

9. A computer-readable memory which stores a program for causing a computer to control a coordinate input apparatus which detects light from a pointing device, with which a coordinate input screen is irradiated, by a coordinate detector, thereby generating a coordinate output signal corresponding to a position on the coordinate input screen, which is irradiated with the light,

said program comprising:

a program code for a storage step of storing a plurality of coordinate values corresponding to outputs from the coordinate detector which are obtained by irradiating a predetermined position on each of a plurality of coordinate input screens with the light, wherein each of the plurality of coordinate input screens is set at different set positions against a direction along an optical axis between the coordinate input screen and the coordinate detector;

a program code for a selection step of selecting a predetermined coordinate input screen from the plurality of coordinate input screens and for selecting coordinate values from the plurality of coordinate values stored in the storage step, which correspond to the predetermined coordinate input screen selected from the plurality of coordinate input screens; and

a program code for an arithmetic step of calculating the position on the predetermined coordinate input screen selected from the plurality of coordinate input screens, which is irradiated with the light, on the basis of the coordinate values selected in the selection step.