MOTION COMPONENT DOMINANCE FACTORS FOR MOTION LOCKING OF TOUCH SENSOR DATA

• US 20090174676A1
• Filed: 09/25/2008
• Published: 07/09/2009
• Est. Priority Date: 01/04/2008
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: WESTERMAN, Wayne Carl
• Application Number:
  US12/238,342
• Publication Number:
  US 20090174676A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text
• CPC Class Codes: G06T 7/337 involving reference images or patches
• CPC Class Codes: G06V 10/421 by analysing segments intersecting the pattern

Abstract

An image jaggedness filter is disclosed that can be used to detect the presence of ungrounded objects such as water droplets or coins, and delay periodic baseline adjustments until these objects are no longer present. To do otherwise could produce inaccurate normalized baseline sensor output values. The application of a global baseline offset is also disclosed to quickly modify the sensor offset values to account for conditions such as rapid temperature changes. Background pixels not part of any touch regions can be used to detect changes to no-touch sensor output values and globally modify the sensor offset values accordingly. The use of motion dominance ratios and axis domination confidence values is also disclosed to improve the accuracy of locking onto dominant motion components as part of gesture recognition.

Claims

1. A method for processing touch images using separable control, comprising:

computing a scale_dominance_ratio (SDR) value and a rotate_dominance_ratio (RDR) value as a function of identified contacts on a touch sensor panel, the SDR and RDR values representing dominance values of a scaling component and a rotational component, respectively, of motion associated with the contacts;

utilizing the SDR and RDR values to determine a motion component to lock onto when performing gesture identification.

2. The method of claim 1, further comprising computing the SDR and RDR values as a function of fingers and thumbs associated with the contacts.

3. The method of claim 1, further comprising:

capturing multiple images of touch;

extracting motion components from the captured images of touch;

computing a smooth translation speed, a smooth rotate speed, and a smooth scale speed from the motion components; and

utilizing the smooth translation speed, the smooth rotate speed, and the smooth scale speed along with the SDR and RDR values to determine the motion component to lock into when performing gesture identification.

4. The method of claim 3, the motion components comprising an x-direction velocity (Vx), a y-direction velocity (Vy), a rotational velocity (Vr), and a scaling velocity (Vs).

5. The method of claim 4, further comprising applying a mathematical low pass filter (LPF) to compute the smooth translation speed, the smooth rotate speed, and the smooth scale speed as:

Smooth_translation_speed = (LPF(Vx)² + LPF(Vy)²)^0.5;

Smooth_rotate_speed = LPF(Vr); and

Smooth_scale_speed = LPF(Vs).

6. The method of claim 2, further comprising setting the SDR and RDR values to 2.5 if a thumb is detected as one of the identified contacts.

7. The method of claim 2, further comprising setting the SDR and RDR values below 2.5 if two or more fingers but no thumbs are detected as the identified contacts.

8. The method of claim 7, further comprising setting the SDR to about 0.25 if a finger separation between at least two of the fingers is between 0 and about 3 cm, setting the SDR between about 0.25 and about 1.25 if the finger separation is between about 3 cm and about 6 cm, and setting the SDR to between about 1.25 and about 2.5 if the finger separation is greater than about 6 cm.

9. The method of claim 8, further comprising setting the SDR to 0.25 even if the finger separation is greater than about 3 cm if a downward translation is detected along with a scale contraction.

10. The method of claim 3, further comprising:

locking onto a translation component and clipping the scaling component of the motion associated with the contacts if the smooth translation speed is greater than the SDR multiplied by the smooth scale speed; and

locking onto the translation component and clipping the rotational component of the motion associated with the contacts if the smooth translation speed is greater than the RDR multiplied by the smooth rotate speed.

11. The method of claim 10, further comprising computing an axis domination confidence value as a representation of an unambiguousness of the motion component to lock onto as:

if the smooth translation speed is less than the smooth scale speed plus the smooth rotate speed, then

$\mathrm{axis\_domination}<br><br>\mathrm{\_confidence}=1-\frac{\mathrm{smooth}<br><br><br><br>\mathrm{translation}<br><br><br><br>\mathrm{speed}}{\left(\begin{array}{c}\mathrm{smooth\_scale}<br><br>\mathrm{\_speed}+\\ \mathrm{smooth\_rotate}<br><br>\mathrm{\_speed}\end{array}\right)},<br><br>\mathrm{otherwise},<br><br>\mathrm{axis\_domination}<br><br>\mathrm{\_confidence}=1-\frac{\left(\begin{array}{c}\mathrm{smooth\_scale}<br><br>\mathrm{\_speed}+\\ \mathrm{smooth\_rotate}<br><br>\mathrm{\_speed}\end{array}\right)}{\mathrm{smooth}<br><br><br><br>\mathrm{translation}<br><br><br><br>\mathrm{speed}}.$

12. The method of claim 11, further comprising delaying the locking onto the motion component by an amount proportional to the axis domination confidence value.

13. The method of claim 11, further comprising multiplying the axis domination confidence value by any non-clipped motion components to delay a locking decision.

14. A computer-readable storage medium storing program code for processing touch images using separable control, the program code for causing performance of a method comprising:

computing a scale_dominance_ratio (SDR) value and a rotate_dominance_ratio (RDR) value as a function of identified finger and thumb contacts on a touch sensor panel, the SDR and RDR values representing dominance values of a scaling component and a rotational component, respectively, of motion associated with the contacts;

utilizing the SDR and RDR values to determine a motion component to lock onto when performing gesture identification, the motion components including an x-direction velocity (Vx), a y-direction velocity (Vy), a rotational velocity (Vr), and a scaling velocity (Vs).

15. The computer-readable storage medium of claim 14, the program code further for causing performance of a method comprising:

capturing multiple images of touch;

extracting the motion components from the captured images of touch;

computing a smooth translation speed, a smooth rotate speed, and a smooth scale speed from the motion components; and

utilizing the smooth translation speed, the smooth rotate speed, and the smooth scale speed along with the SDR and RDR values to determine the motion component to lock into when performing gesture identification.

16. The computer-readable storage medium of claim 15, the program code further for causing performance of a method comprising applying a mathematical low pass filter (LPF) to compute the smooth translation speed, the smooth rotate speed, and the smooth scale speed as:

Smooth_translation_speed = (LPF(Vx)² + LPF(Vy)²)^0.5;

Smooth_rotate_speed = LPF(Vr); and

Smooth_scale_speed = LPF(Vs).

17. The computer-readable storage medium of claim 14, the program code further for causing performance of a method comprising setting the SDR and RDR values to 2.5 if a thumb is detected as one of the identified contacts.

18. The computer-readable storage medium of claim 14, the program code further for causing performance of a method comprising setting the SDR and RDR values below 2.5 if two or more fingers but no thumbs are detected as the identified contacts.

19. The computer-readable storage medium of claim 18, the program code further for causing performance of a method comprising setting the SDR to about 0.25 if a finger separation between at least two of the fingers is between 0 and about 3 cm, setting the SDR between about 0.25 and about 1.25 if the finger separation is between about 3 cm and about 6 cm, and setting the SDR to between about 1.25 and about 2.5 if the finger separation is greater than about 6 cm.

20. The computer-readable storage medium of claim 19, the program code further for causing performance of a method comprising setting the SDR to 0.25 even if the finger separation is greater than about 3 cm if a downward translation is detected along with a scale contraction.

21. The computer-readable storage medium of claim 15, the program code further for causing performance of a method comprising:

locking onto a translation component and clipping the scaling component of the motion associated with the contacts if the smooth translation speed is greater than the SDR multiplied by the smooth scale speed; and

locking onto the translation component and clipping the rotational component of the motion associated with the contacts if the smooth translation speed is greater than the RDR multiplied by the smooth rotate speed.

22. The computer-readable storage medium of claim 21, the program code further for causing performance of a method comprising computing an axis domination confidence value as a representation of an unambiguousness of the motion component to lock onto as:

if the smooth translation speed is less than the smooth scale speed plus the smooth rotate speed, then

$\mathrm{axis\_domination}<br><br>\mathrm{\_confidence}=1-\frac{\mathrm{smooth}<br><br><br><br>\mathrm{translation}<br><br><br><br>\mathrm{speed}}{\left(\begin{array}{c}\mathrm{smooth\_scale}<br><br>\mathrm{\_speed}+\\ \mathrm{smooth\_rotate}<br><br>\mathrm{\_speed}\end{array}\right)},<br><br>\mathrm{otherwise},<br><br>\mathrm{axis\_domination}<br><br>\mathrm{\_confidence}=1-\frac{\left(\begin{array}{c}\mathrm{smooth\_scale}<br><br>\mathrm{\_speed}+\\ \mathrm{smooth\_rotate}<br><br>\mathrm{\_speed}\end{array}\right)}{\mathrm{smooth}<br><br><br><br>\mathrm{translation}<br><br><br><br>\mathrm{speed}}.$

23. The computer-readable storage medium of claim 22, the program code further for causing performance of a method comprising delaying the locking onto the motion component by an amount proportional to the axis domination confidence value.

24. The computer-readable storage medium of claim 22, the program code further for causing performance of a method comprising multiplying the axis domination confidence value by any non-clipped motion components to delay a locking decision.

25. A mobile telephone including a computer-readable storage medium storing program code for processing touch images using separable control, the program code for causing performance of a method comprising:

computing a scale_dominance_ratio (SDR) value and a rotate_dominance_ratio (RDR) value as a function of identified contacts on a touch sensor panel, the SDR and RDR values representing dominance values of a scaling component and a rotational component, respectively, of motion associated with the contacts;

utilizing the SDR and RDR values to determine a motion component to lock onto when performing gesture identification.

26. A media player including a computer-readable storage medium storing program code for processing touch images using separable control, the program code for causing performance of a method comprising:

computing a scale_dominance_ratio (SDR) value and a rotate_dominance_ratio (RDR) value as a function of identified contacts on a touch sensor panel, the SDR and RDR values representing dominance values of a scaling component and a rotational component, respectively, of motion associated with the contacts;

utilizing the SDR and RDR values to determine a motion component to lock onto when performing gesture identification.

27. A personal computer including a computer-readable storage medium storing program code for processing touch images using separable control, the program code for causing performance of a method comprising:

computing a scale_dominance_ratio (SDR) value and a rotate_dominance_ratio (RDR) value as a function of identified contacts on a touch sensor panel, the SDR and RDR values representing dominance values of a scaling component and a rotational component, respectively, of motion associated with the contacts;

utilizing the SDR and RDR values to determine a motion component to lock onto when performing gesture identification.