Coordinate input device and method having first and second sampling devices which sample input data at staggered intervals

• US 6,278,445 B1
• Filed: 08/27/1996
• Issued: 08/21/2001
• Est. Priority Date: 08/31/1995
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tanaka, Atsushi, Tatsumi, Eisaku, Mori, Shigeki, Nagasaki, Katsuhiko
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US08/697,278
• Time in Patent Office: 1,820 Days
• Field of Search: 345/173, 345/174, 345/177, 345/178, 345/179, 178/18.01, 178/18.03, 178/18.05, 178/18.06, 178/19.01, 178/19.03
• US Class Current: 345/178
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

A coordinate input device interpolates sampling data, using less input data and simpler computing. The input data (coordinate information indicative of an input trace) are sampled both with a predetermined cycle (Tn), and at the end of a predetermined time interval after the sampling of the cycle Tn is complete. As a result of the two different samplings, not only the coordinate point determined by the sampling of cycle Tn, but also information indicative of a tangent vector at each coordinate point on the input trace are obtained. The coordinate point and the associated tangent vector information are thus output, so that a trace more faithful to the input trace is obtained using fewer coordinate points.

Claims

1. A coordinate input device comprising:

first sampling means for sampling coordinate data with a predetermined cycle to provide first sample data;

second sampling means for sampling the coordinate data at least at one moment staggered by a predetermined period from the time when said first sampling means sampled the coordinate data to provide second sample data;

generating means for generating additional data based on predetermined relationship between the first sample data and the second sample data; and

output means for providing output data based on the first sample data and the additional data,

wherein the additional data includes information of a change of the coordinate data.

2. The device according to claim 1, wherein said second sampling means samples the coordinate data at the end of a predetermined time interval after said first sampling means sampled said coordinate data.

3. The device according to claim 1, wherein aid second sampling means samples the coordinate data at predetermined timing before and after said first sampling means sampled said coordinate data.

4. The device according to claim 1 wherein the additional data is data indicative of a difference between the first sample data and the second sample data.

5. The device according to claim 1, wherein each data sampled by said first and second sampling means represents a position of each coordinate point plotting a coordinate trace, and the additional data represents a tangent vector at each input point sampled by said first sampling means.

6. The device according to claim 1 further comprising determination means for obtaining a changed amount between a last output data previously provided by said output means and current data which may be output this time, and determining whether the current data should be provided, wherein said output means provides the current output data based on a result of determination by said determination means.

7. A coordinate input method comprising:

a first sampling step of sampling coordinate data with a predetermined cycle to provide first sample data;

a second sampling step of sampling the coordinate data at least at one moment staggered by a predetermined period from the time when said coordinate data was sampled at said first sampling step to provide second sample data;

a generating step of generating additional data based on a predetermined relationship between the first sample data and the second sample data; and

an output step of providing output data based on the first sample data and the additional data,

wherein the additional data includes information of a change of the coordinate data.

8. The method according to claim 7, wherein the additional data is data indicative of a difference between two sampling data from said first and second sampling steps.

9. The method according to claim 7, wherein each data sampled by said first and second sampling steps represents a position of each coordinate point plotting a coordinate trace, and said additional data represents a tangent vector at each coordinate point sampled by said first sampling step.

10. The method according to claim 7 further comprising a determination step of obtaining a changed amount between a last output data previously provided by said output step and current data which may be output at this time, and determining whether the current data should be provided, wherein said output step provides the current output data based on a result of determination by said determination step.

11. A coordinate input device comprising:

first sampling means for sampling coordinate data with a predetermined cycle, the coordinate data representing a position of each coordinate point on a coordinate trace;

second sampling means for sampling said coordinate data at least at one moment staggered by a predetermined period from the time when said first sampling means sampled said coordinate data;

generating means for generating additional data for each sampling data obtained by said first sampling means based on sampling data obtained by said first and second sampling means; and

formation means for forming an output trace based on input points sampled by said first sampling means and the additional data generated by said generating means,

wherein the additional data includes information of a change of coordinate data.

12. A computer readable medium having recorded thereon codes for implementing a computer implementable coordinate input method comprising:

a first sampling step of sampling coordinate data with a predetermined cycle to provide first sample data;

a second sampling step of sampling the coordinate data at least at one moment staggered by a predetermined period from the time when said coordinate data was sampled at said first sampling step to provide second sample data;

a generating step of generating additional data based on a predetermined relationship between the first sample data and the second sample data; and

an output step of providing output data based on the first sample data and the additional data,

wherein the additional data includes information of a change of the coordinate data.

13. The medium according to claim 12, wherein said additional data is data indicative of a difference between two sampling data from said first and second sampling steps.

14. The medium according to claim 12, wherein each data sampled by said first and second sampling steps represents a position of each coordinate point plotting a coordinate trace, and said additional data represents a tangent vector at each coordinate point sampled by said first sampling step.

15. The medium according to claim 12 further comprising a determination step of obtaining a changed amount between a last output data previously supplied by said output step and current data which may be output at this time, and determining whether the current data should be provided, wherein said output step provides the current output data based on a result of determination by said determination step.