Trajectory estimation apparatus, method, and medium for estimating two-dimensional trajectory of gesture

• US 20070171202A1
• Filed: 01/10/2007
• Published: 07/26/2007
• Est. Priority Date: 01/24/2006
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yang, Jing, Bang, Won-chul, Kim, Dong-yoon
• Application Number:
  US11/651,531
• Publication Number:
  US 20070171202A1
• Time in Patent Office: Days
• US Class Current: 345/158
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors

Abstract

A trajectory estimation apparatus, method, and medium using a triaxial accelerometer are provided. The trajectory estimation apparatus includes a motion sensing module which measures an acceleration component for each of three axes from the input 3D gesture using a triaxial accelerometer, a gravitational component removal module which calculates a gravitational acceleration component and removes the gravitational acceleration component from the acceleration component, a gesture determination module which identifies gesture type represented by an acceleration component obtained as the result of the removal performed by the gravitational component removal module, and a compensation module which compensates for the acceleration component obtained as the result of the removal performed by the gravitational component removal module by using different compensation methods for different gesture types.

Claims

1. A trajectory estimation apparatus for reproducing an input three-dimensional (3D) gesture into a two-dimensional (2D) signal, the trajectory estimation apparatus comprising:

a motion sensing module which measures an acceleration component from the input 3D gesture using a triaxial accelerometer;

a gravitational component removal module which calculates a gravitational acceleration component and removes the gravitational acceleration component from the acceleration component;

a gesture determination module which identifies gesture type represented by an acceleration component obtained as the result of the removal performed by the gravitational component removal module; and

a compensation module which compensates for the acceleration component obtained as the result of the removal performed by the gravitational component removal module based on gesture types.

2. The trajectory estimation apparatus of claim 1, wherein the gesture types comprise a closed gesture type and an open gesture type.

3. The trajectory estimation apparatus of claim 2, wherein the gesture determination module determines whether a difference between a gravity directional component of a start point of the input 3D gesture and a gravity directional component of an end point of the input 3D gesture is within a predetermined threshold range.

4. The trajectory estimation apparatus of claim 3, wherein the gesture determination module measures a first pitch at the start point of the input 3D gesture and a second pitch at the end point of the input 3D gesture, calculates a difference between the first pitch and the second pitch, determines the input 3D gesture to be a closed gesture if the difference between the first pitch and the second pitch is within the predetermined threshold range, and determines the input 3D gesture to be an open gesture if the difference between the first pitch and the second pitch is outside the predetermined threshold range.

5. The trajectory estimation apparatus of claim 1, wherein the gravitational component removal module calculates the gravitational acceleration component based on gravitational acceleration linearly changing between an acceleration level slightly before the performing of a gesture and an acceleration level slightly after the performing of the gesture.

6. The trajectory estimation apparatus of claim 1, wherein the compensation module comprises:

a zero velocity compensator which performs zero velocity compensation (ZVC) on the acceleration component obtained as the result of the removal performed by the gravitational component removal module if the input gesture is a closed gesture; and

an estimated end position compensator which performs end position compensation (EPC) on the acceleration component obtained as the result of the removal performed by the gravitational component removal module if the input gesture is an open gesture.

7. The trajectory estimation apparatus of claim 6, wherein the end position compensator performs ZVC on an x component of the acceleration component obtained as the result of the removal performed by the gravitational component removal module, calculates a 2D trajectory by integrating the result of the ZVC, and determines whether a difference between an x component of one end point of the 2D trajectory and an x component of the other end point of the 2D trajectory divided by a difference between a maximum x value and a minimum x value of the 2D trajectory is smaller than a predetermined threshold.

8. The trajectory estimation apparatus of claim 7, wherein, if the difference between the x component of one end point of the 2D trajectory and the x component of the other end point of the 2D trajectory divided by the difference between the maximum x value and the minimum x value of the 2D trajectory is determined to be smaller than the predetermined threshold, the end position compensator sets an x coordinate of an estimated end position to 0, and if the difference between the x component of one end point of the 2D trajectory and the x component of the other end point of the 2D trajectory divided by the difference between the maximum x value and the minimum x value of the 2D trajectory is determined not to be smaller than the predetermined threshold, the end position compensator sets the x coordinate of the estimated end position to be the same as that of an actual end point of the input 3D gesture.

9. The trajectory estimation apparatus of claim 8, wherein the end position compensator performs EPC on the acceleration component obtained as the result of the removal performed by the gravitational component removal module using the x coordinate of the estimated end position and a y coordinate of the estimated end position, wherein the y coordinate of the estimated end position is determined as the square of a difference between a rotation radius and the difference between the first pitch and the second pitch.

10. The trajectory estimation apparatus of claim 9, wherein the end position compensator calculates an x coordinate of an uncompensated end position by integrating the acceleration component obtained as the result of the removal performed by the gravitational component removal module, models an acceleration difference component using the x coordinate of the uncompensated end position and the x coordinate of the estimated end position, and divides the acceleration difference component by the acceleration component obtained as the result of the removal performed by the gravitational component removal module.

11. The trajectory estimation apparatus of claim 10, wherein the end position compensator calculates a y coordinate of an uncompensated end position by integrating the acceleration component obtained as the result of the removal performed by the gravitational component removal module, models an acceleration difference component using the y coordinate of the uncompensated end position and the y coordinate of the estimated end position, and divides the acceleration difference component by the acceleration component obtained as the result of the removal performed by the gravitational component removal module.

12. The trajectory estimation apparatus of claim 10, wherein the acceleration difference component is modeled as a constant or is linearly modeled.

13. The trajectory estimation apparatus of claim 1 further comprising a velocity and position calculation module which calculates a 2D trajectory by integrating the compensated acceleration component.

14. The trajectory estimation apparatus of claim 13 further comprising a tail removal module, which removes a tail of the 2D trajectory.

15. A trajectory estimation method of reproducing an input three-dimensional (3D) gesture into a two-dimensional (2D) signal, the trajectory estimation method comprising:

(a) measuring an acceleration component for each of three axes from the input 3D gesture using a triaxial accelerometer;

(b) calculating a gravitational acceleration component and removing the gravitational acceleration component from the acceleration component;

(c) identifying gesture type represented by an acceleration component obtained as the result of the removal performed in (b); and

(d) compensating for the acceleration component obtained as the result of the removal performed in (b) based on gesture types.

16. The trajectory estimation method of claim 15, wherein the gesture types comprise a closed gesture type and an open gesture type.

17. The trajectory estimation method of claim 16, wherein (c) comprises determining whether a difference between a gravity directional component of a start point of the input 3D gesture and a gravity directional component of an end point of the input 3D gesture is within a predetermined threshold range.

18. The trajectory estimation method of claim 17, wherein (c) comprises:

measuring a first pitch at the start point of the input 3D gesture and a second pitch at the end point of the input 3D gesture; and

calculating a difference between the first pitch and the second pitch, determining the input 3D gesture to be a closed gesture if the difference between the first pitch and the second pitch is within the predetermined threshold range, and determining the input 3D gesture to be an open gesture if the difference between the first pitch and the second pitch is outside the predetermined threshold range.

19. The trajectory estimation method of claim 15, wherein (b) comprises calculating the gravitational acceleration component based on gravitational acceleration linearly changing between an acceleration level slightly before the performing of a gesture and an acceleration level slightly after the performing of the gesture.

20. The trajectory estimation method of claim 15, wherein (d) comprises:

(d1) performing zero velocity compensation (ZVC) on the acceleration component obtained as the result of the removal performed in (b); and

(d2) performing end position compensation (EPC) on the acceleration component obtained as the result of the removal performed in (b) if the input gesture is an open gesture.

21. The trajectory estimation method of claim 20, wherein (d2) comprises:

performing ZVC on an x component of the acceleration component obtained as the result of the removal performed in (b);

calculating 2D trajectory by integrating the result of the ZVC; and

determining whether a difference between an x component of one end point of the 2D trajectory and an x component of the other end point of the 2D trajectory divided by a difference between a maximum x value and a minimum x value of the 2D trajectory is smaller than a predetermined threshold.

22. The trajectory estimation method of claim 21, wherein, if the difference between the x component of one end point of the 2D trajectory and the x component of the other end point of the 2D trajectory divided by the difference between the maximum x value and the minimum x value of the 2D trajectory is determined to be smaller than the predetermined threshold, (d2) comprises setting an x coordinate of an estimated end position to zero, and if the difference between the x component of one end point of the 2D trajectory and the x component of the other end point of the 2D trajectory divided by the difference between the maximum x value and the minimum x value of the 2D trajectory is determined not to be smaller than the predetermined threshold, (d2) comprises setting the x coordinate of the estimated end position to be the same as that of an actual end point of the input 3D gesture.

23. The trajectory estimation method of claim 22, wherein (d2) comprises performing EPC on the acceleration component obtained as the result of the removal performed in (b) using the x coordinate of the estimated end position and a y coordinate of the estimated end position, wherein the y coordinate of the estimated end position is determined as the square of a difference between a rotation radius and the difference between the first pitch and the second pitch.

24. The trajectory estimation method of claim 23, wherein (d2) comprises:

calculating an x coordinate of an uncompensated end position by integrating the acceleration component obtained as the result of the removal performed in (b);

modeling an acceleration difference component using the x coordinate of the uncompensated end position and the x coordinate of the estimated end position; and

dividing the acceleration difference component by the acceleration component obtained as the result of the removal performed in (b).

25. The trajectory estimation method of claim 23, wherein (d2) comprises:

calculating a y coordinate of an uncompensated end position by integrating the acceleration component obtained as the result of the removal performed in (b);

modeling an acceleration difference component using the y coordinate of the uncompensated end position and the y coordinate of the estimated end position; and

dividing the acceleration difference component by the acceleration component obtained as the result of the removal performed in (b)

26. The trajectory estimation method of claim 24, wherein the acceleration difference component is modeled as a constant or is linearly modeled.

27. The trajectory estimation method of claim 15 further comprising calculating a 2D trajectory by integrating the compensated acceleration component.

28. The trajectory estimation method of claim 27 further comprising removing a tail of the 2D trajectory.

29. At least one computer readable medium storing instructions that control at least one processor to perform a trajectory estimation method of reproducing an input three-dimensional (3D) gesture into a two-dimensional (2D) signal, the trajectory estimation method comprising:

(a) measuring an acceleration component for each of three axes from the input 3D gesture using a triaxial accelerometer;

(b) calculating a gravitational acceleration component and removing the gravitational acceleration component from the acceleration component;

(c) identifying gesture type represented by an acceleration component obtained as the result of the removal performed in (b); and

(d) compensating for the acceleration component obtained as the result of the removal performed in (b) based on gesture types.

30. At least one computer readable medium as recited in claim 29, wherein the gesture types comprise a closed gesture type and an open gesture type.

31. At least one computer readable medium as recited in claim 29, wherein (d) comprises:

(d1) performing zero velocity compensation (ZVC) on the acceleration component obtained as the result of the removal performed in (b); and

(d2) performing end position compensation (EPC) on the acceleration component obtained as the result of the removal performed in (b) if the input gesture is an open gesture.