COORDINATE INPUT DEVICE

• US 20080142280A1
• Filed: 12/06/2007
• Published: 06/19/2008
• Est. Priority Date: 12/13/2006
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: YAMAMOTO, Sadao, Onoda, Naoto
• Granted Patent: US 8,587,527 B2
• Time in Patent Office: Days
• US Class Current: 178/18.02
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A coordinate input device is provided. The coordinate input device includes a first input device for detecting a position input and obtaining a first input value indicate of the position, a second input device for detecting the position input and obtaining a second input value indicative of the position, the second input value having a tendency to be a more accurate indication of the position than the first input value, a determining unit configured to determine whether the first input device and the second input device simultaneously obtain the first input value and the second input value, respectively, a storing unit configured to store a relationship between the first input value from the first input device and the second input value from the second input device as correction information, and a correcting unit configured to correct the first input value on the basis of the correction information.

Claims

1. A coordinate input device, comprising:

a first input device for detecting a position input and obtaining a first input value indicative of the position input;

a second input device for detecting the position input and obtaining a second input value, the second input value having a tendency to be a more accurate indication of the position than the first input value;

a determining unit configured to determine whether the first input device and the second input device simultaneously obtain the first input value and the second input value, respectively;

a storing unit configured to store a relationship between the first input value from the first input device and the second input value from the second input device as correction information; and

a correcting unit configured to correct the first input value on the basis of the correction information.

2. A coordinate input device according to claim 1, wherein the second input value comprises the correction information for the first input value.

3. A coordinate input device according to claim 1, wherein the correction information comprises a parameter value used to calculate the corrected first input value from a value obtained from the first input device.

4. A coordinate input device according to claim 1, wherein the correction information comprises a difference value between the first input value and the second input value.

5. A coordinate input device according to claim 1, further comprising:

a position indicator capable of simultaneous input on the first input device and the second input device;

a display operably associated with the first and second input devices, the display displaying the position detected by the first and second input devices,

wherein the display displays instructions to input the first input value and the second input value using the position indicator within a range corresponding to at least one predetermined area of the first input device and the second input device.

6. A coordinate input device according to claim 5, wherein the display device is laid on the first input device and the second input device, and the at least one predetermined area is displayed on the display device.

7. A coordinate input device according to claim 1, wherein the correction information is stored in a correction table for each coordinate of the first input value each time the first input value and the second input value are simultaneously obtained.

8. A coordinate input device according to claim 7, wherein the correction table includes a first correction table used for correcting the first input value and a second correction table for storing difference information between each coordinate of the first input value and each corresponding coordinate of the second input value, and the difference information stored in the second correction table is written into the first correction table at a predetermined time.

9. A coordinate input device according to claim 3, wherein the parameter value includes a first parameter value used for correcting the first input value and a second parameter value stored each time the first input device and the second input device simultaneously obtain the first input value and the second input value, respectively, and the first parameter value is set to the second parameter value at a predetermined time.

10. A coordinate input device according to claim 8, wherein the predetermined time is determined by determining whether a predetermined amount of time has elapsed since the first parameter value was last set to the second parameter value or determining whether an instruction of a user to set the parameter has been received or determining whether a system is in startup mode.

11. A coordinate input device according to claim 1, wherein the first input device comprises a pressure-sensitive sensor and the second input device comprises an electromagnetic-induction sensor.

12. A coordinate input device according to claim 11, wherein:

the first input value is detected by the pressure-sensitive sensor simultaneously with a detection of the second input value by the electromagnetic-induction sensor, and

an output of the electromagnetic-induction sensor is compared with an output of the pressure-sensitive sensor to obtain the correction information.

13. A coordinate input device according to claim 1, wherein said storing unit updates the correction information in real time to account for degradation in performance of the first input device that occurs with repeated use of the first input device.

14. A digitizer tablet having a pointing device, the digitizer tablet comprising:

a first input device for sensing a first type of position input used to calculate a first input value;

a second input device operably associated with the pointing device, said second input device interacting with the pointing device for sensing a second type of position input used to calculate a second input value;

a correction processing unit for correcting the first input value based on a comparison between previous first and second input values received for the same position input by the first and second input devices, respectively; and

an output selecting unit for selecting the second input value to be output whenever the second type of position input is sensed and for selecting the corrected first input value to be output whenever the second type of position input is not sensed.

15. A digitizer tablet according to claim 14, wherein said first input device comprises a touch panel, and the first type of position input comprises a touch position input.

16. A digitizer tablet according to claim 15, wherein said correction processing unit corrects the first input value to compensate for inaccuracies in the first input value.

17. A digitizer tablet according to claim 14, further comprising:

a correction table for storing correction information for adjusting various first input values to be closer to corresponding second input values for the same position input, said correction table being accessible by said correction processing unit.

18. A digitizer tablet according to claim 14, further comprising:

a correction table for storing correction information for adjusting various first input values to be closer to corresponding second input values for the same position input, said correction table being accessible by said correction processing unit;

a difference detecting unit for determining a difference between the first and second input values whenever the first and second input devices simultaneously detect the pointing device; and

a difference table for storing recent difference values between the first and second input values and for updating the correction information of said correction table whenever a predetermined event occurs.

19. A digitizer tablet according to claim 18, wherein the predetermined event comprises one of an expiration of a time period, receipt of an update instruction from a user, and a comparison between the first and second input values as being outside a predetermined range defined by the difference value stored in said difference table in association with a current first input value.

20. A digitizer tablet according to claim 14, wherein said second input device comprises an electromagnetic induction type sensor having a plurality of inductive coils for electromagnetic interaction with a resonant circuit in the pointing device.

21. A coordinate input device comprising:

first input means for detecting a position input and obtaining a first input value indicative of the position input;

second input means for detecting the position input and obtaining a second input value indicative of the position input, the second input value having a tendency to be a more accurate indication of the position than the first input value;

means for determining whether the first input device and the second input device simultaneously obtain the first input value and the second input value, respectively;

means for storing a relationship between the first input value from the first input device and the second input value from the second input device as correction information; and

means for correcting the first input value on the basis of the correction information.

22. A method of detecting a coordinate input on a digitizer tablet having first and second input devices of differing degrees of accuracy, the method comprising the steps of:

detecting a position input using the first input device and obtaining a first input value indicative of the position input;

detecting the position input using the second input device and obtaining a second input value, the second input value having a tendency to be a more accurate indication of the position than the first input value;

determining whether the first input device and the second input device simultaneously obtain the first input value and the second input value, respectively;

storing a relationship between the first input value from the first input device and the second input value from the second input device as correction information when it is determined that the first and second input devices simultaneously receive the first and second input values, respectively; and

correcting the first input value on the basis of the correction information when it is determined that only the first input device receives the first input value.

23. The method according to claim 22, wherein the storing of the relationship between the first input value and the second input value comprises:

determining a difference between the first and second input values;

storing recent difference values between the first and second input values for a simultaneous detection of the position input; and

updating the stored correction information with the recent difference values in real time whenever a predetermined event occurs.

24. The method according to claim 23, wherein the updating of the correction information whenever the predetermined event occurs comprises updating the correction information whenever an expiration of a time period occurs, an update instruction is received from a user, or a comparison between the first and second input values is determined to be outside a predetermined range defined by a current difference value stored in association with the obtained first input value.

25. A computer readable medium containing executable code for controlling a digitizer tablet having a pointing device and first and second input devices, the medium comprising:

executable code for calculating a first input value from a first type of position input sensed by the first input device;

executable code for calculating a second input value from a second type of position input sensed by the second input device through interaction with the pointing device;

executable code for correcting the first input value based on a comparison between previous first and second input values received for the same position input by the first and second input devices, respectively; and

executable code for selecting the second input value to be output whenever the second type of position input is sensed and for selecting the corrected first input value to be output whenever the second type of position input is not sensed.