Method and system for detecting touch events based on redundant validation

• US 20090009488A1
• Filed: 07/02/2007
• Published: 01/08/2009
• Est. Priority Date: 07/02/2007
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Elo Touch Solutions, Inc.
• Inventors: D'Souza, Henry M., Kent, Joel C., Aroyan, James L.
• Granted Patent: US 8,730,213 B2
• Time in Patent Office: Days
• US Class Current: 345/177
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

A method of detecting a touch event on an acoustic fingerprint based touch system comprises digitizing at least two signals to form first and second sets of digitized signals. The at least two signals are received from at least two sensors on a touch panel. A frequency transform is performed upon the first and second sets of digitized signals to form first and second frequency transform data sets of frequency components. At least first and second live fingerprints are constructed wherein at least one of the first and second live fingerprints is based on the first and second frequency transform data sets. A touch location is identified based on the at least first and second live fingerprints.

Claims

1. A method of detecting a touch event on an acoustic fingerprint based touch system, comprising:

digitizing at least two signals to form first and second sets of digitized signals, wherein the at least two signals are received from at least two sensors associated with a touch panel;

performing a frequency transform upon the first and second sets of digitized signals to form first and second frequency transform data sets of frequency components;

constructing at least first and second live fingerprints wherein at least one of the first and second live fingerprints is based on the first and second frequency transform data sets; and

identifying a touch location based on the at least first and second live fingerprints.

2. The method of claim 1, further comprising:

calculating amplitude magnitudes associated with the first and second frequency transform data sets; and

determining a magnitude ratio between the amplitude magnitudes, wherein at least one of the first and second live fingerprints is constructed based on the magnitude ratio.

3. The method of claim 1, further comprising:

calculating phase information associated with the first and second frequency transform data sets; and

determining a phase difference based on the phase information, wherein at least one of the first and second live fingerprints is constructed based on the phase difference.

4. The method of claim 1, further comprising:

comparing each of the at least first and second live fingerprints to a plurality of template fingerprints wherein each of the template fingerprints is associated with coordinates on the touch panel; and

identifying a best matching template fingerprint associated with each of the at least first and second live fingerprints based on the comparison, the touch location being further identified based on the best matching template fingerprints.

5. The method of claim 1, further comprising:

identifying at least first and second best matching template fingerprints associated with the at least first and second live fingerprints wherein the template fingerprints are each associated with coordinates on the touch panel;

determining a distance between the coordinates associated with the at least first and second best matching template fingerprints; and

identifying the touch location based on the coordinates associated with the at least first and second best matching template fingerprints when the distance is less than a predetermined threshold.

6. The method of claim 1, further comprising:

identifying at least first and second best matching template fingerprints associated with the at least first and second live fingerprints wherein the template fingerprints are each associated with coordinates on the touchscreen;

determining a distance between the coordinates associated with the at least first and second best matching template fingerprints; and

discarding the at least first and second live fingerprints when the distance is greater than a predetermined threshold.

7. The method of claim 1, further comprising:

calculating amplitude magnitudes and phase information associated with the first and second frequency transform data sets;

determining a magnitude ratio between the amplitude magnitudes; and

determining a phase difference based on the phase information, wherein the first live fingerprint is constructed based on the magnitude ratio and the second live fingerprint is constructed based on the phase difference.

8. An acoustic fingerprint based touch system, comprising:

a touch panel;

at least two sensors interconnected with the touch panel, the at least two sensors obtaining at least two signals associated with the touch panel; and

a processor module to perform frequency transforms based on the at least two signals, the processor module producing frequency transform signals, the processor module constructing at least two live fingerprints based on the frequency transform signals, the processor module determining coordinates associated with a touch event on the touch panel based on the at least two live fingerprints.

9. The touch system of claim 8, wherein the frequency transform signals further comprise at least two first and second frequency transform data sets, and wherein the processor module constructs at least one of the at least two live fingerprints based on at least two of the at least two first and second frequency transform data sets.

10. The touch system of claim 8, further comprising a memory storing at least one calibration file having a plurality of template fingerprints associated with known coordinates on the touch panel, the processor module comparing the at least two live fingerprints to the plurality of template fingerprints to determine differences there-between, the processor module further determining the coordinates associated with the touch event based on the differences.

11. The touch system of claim 8, further comprising a memory storing at least one calibration file having a plurality of template fingerprints associated with known coordinates on the touch panel, the processor module comparing the at least two live fingerprints to the plurality of template fingerprints to determine differences there-between, the processor module rejecting a live fingerprint when the associated difference is greater than a predetermined threshold based on spatial distance.

12. The touch system of claim 8, further comprising a memory storing at least one calibration file having a plurality of template fingerprints associated with known coordinates on the touch panel, the processor module identifying at least first and second best matching template fingerprints associated with the at least first and second live fingerprints, the processor module determining the coordinates associated with the touch event based on sufficient agreement between the at least first and second live fingerprints.

13. The touch system of claim 8, further comprising a memory storing at least one calibration file having a plurality of template fingerprints associated with known coordinates on the touch panel, the processor module identifying at least first and second best matching template fingerprints associated with the at least first and second live fingerprints, the processor module determining the coordinate location associated with the touch event based on an average coordinate, wherein the average coordinate is based on the coordinates associated with the at least first and second best matching template fingerprints.

14. The touch system of claim 8, wherein the processor module calculates amplitude magnitudes and phase information associated with the frequency transform signals, the processor module determining a magnitude ratio between the amplitude magnitudes and a phase difference based on the phase information, the processor module constructing a first live fingerprint based on the magnitude ratio and a second live fingerprint based on the phase difference.

15. The touch system of claim 8, wherein the at least two live fingerprints comprise P live fingerprints where P is an integer greater than two, the system further comprising a memory storing at least one calibration file having a plurality of template fingerprints associated with known coordinates on the touch panel, the processor module identifying P best matching template fingerprints associated with the P live fingerprints, the processor module determining the coordinates associated with the touch event based on majority logic.

16. A computer readable medium for use in an acoustic fingerprint based touch system, comprising:

instructions to digitize signals from at least two sensors on a touch panel to form first and second sets of digitized signals;

instructions to perform a frequency transform upon the first and second sets of digitized signals to form first and second frequency transform data sets of frequency components;

instructions to construct at least two live fingerprints based on the first and second frequency transform data sets; and

instructions to determine coordinates on the touch panel associated with a touch event based on the at least two live fingerprints.

17. The computer readable medium of claim 16, further comprising:

instructions to calculate amplitude magnitudes and phase information associated with the first and second frequency transform data sets;

instructions to determine a magnitude ratio between the amplitude magnitudes and a phase difference based on the phase information; and

instructions to construct a first live fingerprint based on the magnitude ratio and a second live fingerprint based on the phase difference.

18. The computer readable medium of claim 16, wherein the at least two live fingerprints comprise P live fingerprints where P is an integer greater than two, the method further comprising:

instructions to compare the P live fingerprints to a plurality of template fingerprints associated with known coordinates on the touch panel;

instructions to identify P best matching template fingerprints associated with the P live fingerprints based on the comparison; and

instructions to determine the coordinates associated with the touch event based on the P best matching template fingerprints and majority logic.

19. The computer readable medium of claim 16, further comprising:

instructions to compare the at least two live fingerprints to a plurality of template fingerprints associated with known coordinates on the touch panel;

instructions to identify best matching template fingerprints associated with the at least two live fingerprints;

instructions to determine a distance between the coordinates associated with the best matching template fingerprints; and

instructions to identify the touch location based on the coordinates associated with the at least first and second best matching template fingerprints when the distance is less than a predetermined threshold.

20. The computer readable medium of claim 16, wherein the at least two live fingerprints comprise at least a first and second live fingerprints, the computer readable medium further comprising instructions to compare the first and second live fingerprints to first and second calibration files, respectively, wherein each of the calibration files comprises a plurality of template fingerprints associated with known coordinates on the touch panel, wherein the plurality of template fingerprints within the first calibration file are constructed based on a first processing method and the plurality of template fingerprints within the second calibration file are constructed based on a second processing method that is different with respect to the first processing method.