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

• US 20020075386A1
• Filed: 08/01/2001
• Published: 06/20/2002
• Est. Priority Date: 08/07/2000
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi
• Granted Patent: US 6,795,061 B2
• Time in Patent Office: Days
• US Class Current: 348/141
• 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 plurality of predetermined positions on the coordinate input screen with the light;

selection means for selecting a coordinate values from the plurality of coordinate values stored by said storage means; and

arithmetic means for calculating the position on the coordinate input screen, 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 plurality of predetermined positions on the coordinate input screen 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 plurality of predetermined positions on the coordinate input screen 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 plurality of predetermined positions on the coordinate input screen 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:

the storage step of storing a plurality of coordinate values corresponding to outputs from the coordinate detector which are obtained by irradiating a plurality of predetermined positions on the coordinate input screen with the light;

the selection step of selecting a coordinate values from the plurality of coordinate values stored in the storage step; and

the arithmetic step of calculating the position on the coordinate input screen, 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 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 plurality of predetermined positions on the coordinate input screen with the light.

7. The method according to claim 5, wherein 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 plurality of predetermined positions on the coordinate input screen with the light.

8. The method according to claim 5, wherein 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 plurality of predetermined positions on the coordinate input screen 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 of the storage step of storing a plurality of coordinate values corresponding to outputs from the coordinate detector which are obtained by irradiating a plurality of predetermined positions on the coordinate input screen with the light;

a program code of the selection step of selecting predetermined coordinate values from the plurality of coordinate values stored in the storage step; and

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