Mapped variable smoothing evolution method and device

• US 10,120,461 B2
• Filed: 04/30/2014
• Issued: 11/06/2018
• Est. Priority Date: 05/01/2013
• Status: Active Grant

• Current Assignee: InterDigital Madison Patent Holdings SAS (InterDigital, Inc.)
• Original Assignee: IDHL Holdings, Inc. (InterDigital, Inc.)
• Inventors: Cook, Bryan A., Li, Yun
• Primary Examiner(s): Nguyen, Jennifer
• Application Number:
  US14/888,255
• Publication Number:
  US 20160077609A1
• Time in Patent Office: 1,651 Days
• Field of Search: 345156-157, 345169
• 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
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry

Abstract

The present inventions generally relate to methods and dedicated apparatuses outputting a variable mapped on a device orientation in a non-inertial reference system, with the device orientation being estimated using measurements of motion sensors (such as 3D accelerometers and gyroscopes) and a magnetometer or other similar sensors including cameras. A variable mapped on an orientation of a device is smoothed to have a gradual evolution by adjusting the estimated orientation of the device obtained via sensor fusion or other sensor processing to take into consideration a current measured angular velocity.

Claims

1. A method for smoothing evolution of a variable depending on an orientation of a device, the method comprising:

determining an adjusted angular velocity (Ω

_s,n) based on a measured angular velocity (ω

_n) and an estimated angular velocity (Ω

_f,n), such that to satisfy one or more predefined constraints, including at least one constraint for masking of any of a correction and an artifact;

determining a current value (x) of the variable according to an adjusted estimate of the current orientation (q_s,n) of the device obtained using the adjusted angular velocity (Ω

_s,n); and

outputting the current value (x) of the variable.

2. The method of claim 1, wherein the variable defines any of a position of a cursor on a screen and an image displayed to a video-game user.

3. The method of claim 1, wherein the adjusted estimate of the current orientation of the device, and the measured, estimated and adjusted angular velocities are expressed in a reference system defined relative to gravity direction and Earth magnetic field direction.

4. The method of claim 1, further comprising:

calculating the estimated angular velocity (Ω

_f,n) using an estimate of a current orientation (q_f,n) of the device and an adjusted estimate of a previous orientation (q_s,n-1) of the device.

5. The method of claim 4, wherein the estimate of the current orientation (q_f,n) of the device is obtained using a sensor fusion method, wherein the sensor fusion method uses measurements of any of a magnetometer and an accelerometer, and wherein the measured angular velocity is obtained using a gyroscope.

6. The method of claim 5, wherein the estimate of the current orientation (q_f,n) and the adjusted estimate of a previous orientation (q_s,n-1) are expressed as quaternions.

7. The method of claim 1, wherein the one of more predetermined constraints include the adjusted angular velocity (Ω

_s,n) being substantially equal to zero when the measured angular velocity (ω

_n) is substantially equal to zero.

8. The method of claim 1, wherein the determining of the adjusted angular velocity (Ω

_s,n) includes projecting the estimated angular velocity (Ω

_f,n) along a direction of the measured angular velocity (ω

_n),

calculating a scaling factor (α

) as a ratio of the result of the projecting and a magnitude of the measured angular velocity (ω

_n); and

if the scaling factor exceeds a predetermined first value (MaxScaling) or is below a predetermined second value (MinScaling), setting the scaling factor (α

) equal to the predetermined first value or to the predetermined second value, respectively,

wherein a magnitude of the adjusted angular velocity (Ω

_s,n) is equal to the magnitude of the measured angular velocity (ω

_n) multiplied with the scaling factor.

9. The method of claim 1, wherein the determining of the adjusted angular velocity (Ω

_s,n) includes;

determining an auxiliary unit vector (v₂) based on a first unit vector (v₀) along the measured angular velocity (ω

_n), a second unit vector (v₁) along the estimated angular velocity (Ω

_f,n) and an angle (θ

) there-between; and

determining a unit vector (v) along the adjusted angular velocity (Ω

_s,n) using the first, second and auxiliary unit vectors.

10. The method of claim 9, wherein the unit vector (v) is the second unit vector (v₁) if the angle (θ

) between the measured angular velocity (ω

_n) and the estimated angular velocity (Ω

_f,n) is less than or equal to a maximum angle (θ

_max).

11. The method of claim 10, wherein if the angle (θ

) is larger than the maximum angle (θ

_max), then the unit vector (v) is at the maximum angle from the measured angular velocity (ω

_n), between and in a same plane as the measured angular velocity (ω

_n) and the estimated angular velocity (Ω

_f,n).

12. The method of claim 11, wherein the determining of the adjusted angular velocity (Ω

_s,n) includes projecting the estimated angular velocity (Ω

_f,n) along a direction of the measured angular velocity (ω

_n),

calculating a scaling factor (α

) as a ratio of the result of the projecting and a magnitude of the measured angular velocity (ω

_n); and

if the scaling factor (α

) exceeds a predetermined first value (MaxScaling) or is below a predetermined second value (MinScaling), setting the scaling factor (α

) equal to the predetermined first value or to the predetermined second value, respectively,

wherein a magnitude of the adjusted angular velocity (Ω

_s,n) is equal to the magnitude of the measured angular velocity (ω

_n) multiplied with the scaling factor (α

).

13. The method of claim 12, further comprising:

adjusting at least one of the predetermined first value (MaxScaling), the predetermined second value (MinScaling) and the maximum angle (θ

_max).

14. The method of claim 1, further comprising:

outputting a stabilized current orientation which is equal to a stabilized previous orientation (q′

_s,n-1) if a difference between the adjusted estimate of the current orientation (q_s,n) and the stabilized previous orientation (q′

_s,n-1) is less than a predetermined threshold (m).

15. The method of claim 14, wherein if a difference between the adjusted estimate of the current orientation (q_s,n) and the stabilized previous orientation (q′

_s,n-1) exceeds the predetermined threshold (m), then the stabilized current orientation (q′

_s,n) is equal to the adjusted estimate of the current orientation (q_s,n) after being shifted with the predetermined threshold, towards the stabilized previous orientation (q′

_s,n-1).

16. The method of claim 1, wherein the adjusted estimate of the current orientation (q_s,n) of the device is obtained by adding to a previous orientation (q_s,n-1) of the device, a change thereof obtained by integrating the adjusted angular velocity (Ω

_s,n) over a time interval.

17. A gaming system configured to display an image to a user according to an orientation of a device, the system comprising:

sensors mounted on the device and configured to acquire information leading to a measured angular velocity (ω

_n) and an estimate of a current orientation (q_f,n) of the device; and

a data processing unit configured to determine;

an adjusted angular velocity (Ω

_s,n) based on the measured angular velocity (ω

_n) and the estimated angular velocity (Ω

_f,n), such that to satisfy one or more predefined constraints, including at least one constraint for masking of any of a correction and an artifact;

an adjusted estimate of the current orientation (q_s,n) of the device obtained using the adjusted angular velocity (Ω

_s,n); and

the image to be displayed to the user according to the adjusted estimate of the current orientation.

18. An information system controlled by orientation of a device, the system comprising:

sensors mounted on the device and configured to acquire information leading to a measured angular velocity (ω

_n) and an estimate of a current orientation (q_f,n) of the device; and

a data processing unit configured to determine;

an adjusted angular velocity (Ω

_s,n) based on the measured angular velocity (ω

_n) and the estimated angular velocity (Ω

_f,n), such that to satisfy one or more predefined constraints, including at least one constraint for masking of any of a correction and an artifact;

an adjusted estimate of the current orientation (q_s,n) of the device obtained using the adjusted angular velocity (Ω

_s,n); and

a position of a cursor on a screen based on the current orientation (q_s,n) of the device.

19. An apparatus directed to smoothing evolution of a variable depending on an orientation of a device, the apparatus comprising circuitry, including a processor and memory, configured to:

determine an adjusted angular velocity (Ω

_s,n) based on a measured angular velocity (ω

_n) and an estimated angular velocity (Ω

_f,n), such that to satisfy one or more predefined constraints, including at least one constraint for masking of any of a correction and an artifact; and

determine a current value (x) of the variable according to an adjusted estimate of the current orientation (q_s,n) of the device obtained using the adjusted angular velocity (Ω

_s,n); and

output the current value (x) of the variable.

20. The apparatus of claim 19, wherein the circuitry is configured to determine the adjusted angular velocity (Ω

_s,n) by, at least in part;

projecting the estimated angular velocity (Ω

_f,n) along a direction of the measured angular velocity (ω

_n),

calculating a scaling factor (α

) as a ratio of the result of the projecting and a magnitude of the measured angular velocity (ω

_n); and

if the scaling factor exceeds a predetermined first value (MaxScaling) or is below a predetermined second value (MinScaling), setting the scaling factor (α

) equal to the predetermined first value or to the predetermined second value, respectively,

wherein a magnitude of the adjusted angular velocity (Ω

_s,n) is equal to the magnitude of the measured angular velocity (ω

_n) multiplied with the scaling factor.

21. The apparatus of claim 19, wherein the circuitry is configured to determine the adjusted angular velocity (Ω

_s,n) by, at least in part;

determining an auxiliary unit vector (v₂) based on a first unit vector (v₀) along the measured angular velocity (ω

_n), a second unit vector (v₁) along the estimated angular velocity (Ω

_f,n) and an angle (θ

) there-between; and

determining a unit vector (v) along the adjusted angular velocity (Ω

_s,n) using the first, second and auxiliary unit vectors.

22. The apparatus of claim 21, wherein the unit vector (v) is the second unit vector (v₁) if the angle (θ

) between the measured angular velocity (ω

_n) and the estimated angular velocity (Ω

_f,n) is less than or equal to a maximum angle (θ

_max).

23. The apparatus of claim 22, wherein if the angle (θ

) is larger than the maximum angle (θ

_max), then the unit vector (v) is at the maximum angle from the measured angular velocity (ω

_n), between and in a same plane as the measured angular velocity (ω

_n) and the estimated angular velocity (Ω

_f,n).

24. The apparatus of claim 19, wherein the circuitry is configured to:

output a stabilized current orientation which is equal to a stabilized previous orientation (q′

_s,n-1) if a difference between the adjusted estimate of the current orientation (q_s,n) and the stabilized previous orientation (q′

_s,n-1) is less than a predetermined threshold (m).

25. The apparatus of claim 24, wherein if a difference between the adjusted estimate of the current orientation (q_s,n) and the stabilized previous orientation (q′

_s,n-1) exceeds the predetermined threshold (m), then the stabilized current orientation (q′

_s,n) is equal to the adjusted estimate of the current orientation (q_s,n) after being shifted with the predetermined threshold, towards the stabilized previous orientation (q′

_s,n-1).

26. The apparatus of claim 19, wherein the adjusted estimate of the current orientation (q_s,n) of the device is obtained by adding to a previous orientation (q_s,n-1) of the device, a change thereof obtained by integrating the adjusted angular velocity (Ω

_s,n) over a time interval.