Coordinate input apparatus and calibration method for the same

• US 5,471,226 A
• Filed: 10/07/1992
• Issued: 11/28/1995
• Est. Priority Date: 03/27/1989
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Suzuki, Noriyuki, Takeuchi, Shinsuke
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): Mengistu, Amare
• Application Number:
  US07/958,454
• Time in Patent Office: 1,147 Days
• Field of Search: 340/706, 340/709, 340/707, 178/18, 178/19, 178/20, 345/173, 345/178
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment

Abstract

A coordinate input apparatus includes a coordinate input member for inputting the coordinate value of an indicated position by pointing to a desired position with an indicating pen, a display device for displaying in dot form the indicated position of the indicating pen on the coordinate input member, an instruction device for instructing a calibration process for matching the coordinate systems of the coordinate input member and the display device, a correction parameter derivation device for deriving a correction parameter for matching coordinate systems on the basis of the indication by the indicating pen to a specific region of the coordinate input member when the instruction device has instructed, a coordinate value derivation device for deriving the coordinate value of the indicated position of the indicating pen to the specific region by using the correction parameter derived by the correction parameter derivation device, and a judgment device for judging the validity of the correction parameter according to whether or not the coordinate value derived by the coordinate value derivation device belongs to the specific region.

Claims

1. A coordinate input apparatus, comprising:

a coordinate input member having a first coordinate system for inputting a coordinate value of an indicated position thereon indicated at a desired position with an indicating pen;

display means having a second coordinate system for displaying in dot form the indicated position of said indicating pen on said coordinate input member;

instruction means for instructing a calibration process for matching the coordinate systems of said coordinate input member and said display means when a specific region on said coordinate input member has been indicated by said indicating pen;

display controlling means for displaying a pattern by said display means to be indicated by said indicating pen, which is necessary to derive a correction parameter for matching the coordinate systems when said instruction means has instructed;

correction parameter derivation means for deriving a correction parameter on the basis of a prescribed indication by said indicating pen at the position on said coordinate input member corresponding to said pattern;

prompting means for prompting an operator to indicate a specific region on said coordinate input member by said indicating pen again after a correction parameter is derived by said correction parameter derivation means;

judgment means for Judging whether the indicated position coordinate by the indicating pen belongs to said specific region on said coordinate input member on the basis of the indicated position coordinate value derived by using the correction parameter derived by said correction parameter derivation means; and

coordinate value derivation means for deriving the coordinate value of the indicated position by said indicating pen using the correction parameter derived by the correction parameter derivation means when said judgment means judges that the indicated position coordinate by the indication pen belongs to the specific region.

2. A coordinate input apparatus according to claim 1, wherein said coordinate input section is made of a transparent glass plate and said display means is a liquid crystal indicator positioned directly under the glass plate.

3. A coordinate input apparatus, comprising:

a coordinate input member including a glass plate having a first coordinate system for inputting a coordinate value of an indicated position indicated at a desired position with an indicating pen;

display means, including a screen, having a second coordinate system and positioned directly under the glass plate, for displaying in dot form the indicated position of said indicating pen on said coordinate input member;

instruction means for instructing a calibration process for matching the coordinate systems of said coordinate input member and said display means when an indication by said indicating pen has been effected in correspondence with a specific region of said display means;

display controlling means for displaying a pattern by said display means to be indicated by said indicating pen, which is necessary to derive a correction parameter for matching the coordinate systems when said instruction means has instructed a calibration process;

correction parameter derivation means for deriving a correction parameter an indication by said indicating pen at the position on said coordinate input member corresponding to said pattern;

prompting means for prompting an operator to indicate a specific region on said coordinate input member by said indicating pen again after a correction parameter is derived by said correction parameter derivation means;

judging means for judging whether the indicated position coordinate by the indicating pen belongs to said specific region on said coordinate input member on the basis of the indicated position coordinate value derived by using the correction parameter derived by said correction parameter derivation means; and

coordinate value derivation means for deriving the coordinate value of the indicated position by said indicating pen using the correction parameter derived by the correction parameter derivation means when said judging means judges that the indicated position coordinate by the indicating pen belongs to said specific region.

4. A coordinate input apparatus according to claim 3, wherein said display means is a liquid crystal indicator.