Gyro mouse de-drift and hand jitter reduction

• US 8,786,549 B2
• Filed: 03/11/2011
• Issued: 07/22/2014
• Est. Priority Date: 03/11/2011
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Fu, Guoyi
• Primary Examiner(s): Awad, Amr
• Assistant Examiner(s): MATTHEWS, ANDRE L
• Application Number:
  US13/046,217
• Publication Number:
  US 20120229385A1
• Time in Patent Office: 1,229 Days
• Field of Search: None
• US Class Current: 345/161
• 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 3/03543 Mice or pucks G06F3/03541 takes precedence
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors

Abstract

A gyroscope-based device uses a probability model to assign probability of the device being in an intended static state to each received sample of gyroscope data. A new drift error compensation offset and new hand jitter factor are computed for each sample of gyroscope data based on the assigned probability. In this manner, the magnitude of the hand jitter factor varies with the probability of the device being in an intended static state.

Claims

1. A gyroscope-based device comprising:

an input for receiving angle velocity data obtained from digitized gyroscope sensor data;

a first summation node for reducing said angle velocity data by a drift error compensation offset;

a first multiplication node for multiplying the result of said first summation node by a variable hand jitter compensation factor to produce a new angle velocity; and

an output node for outputting said new angle velocity;

wherein;

the value of said variable hand jitter compensation factor is dependent upon a computation of involuntary movement currently experienced by said gyroscope-based device as determined from a currently received angle velocity datum;

said computation of involuntary movement is a computation of probability of said gyroscope-based device being in a static state;

each current sample n of said digitized gyroscope sensor data defines a current cycle;

said currently received angle velocity datum is identified as G_Corr(n) and is obtained from current sample n of said digitized gyroscope sensor data;

the new angle velocity obtained from the current sample n of said digitized gyroscope sensor data is denoted as G_New(n); and

said gyroscope-based device further comprising;

a) a probability processing unit receiving said intermediate angle velocity and determining a probability p(n) value for the current sample n, said probability p(n) being said computation of probability of said gyroscope-based device being in a static state within the current cycle defined by current sample n; and

wherein the value of said variable hand jitter compensation factor for the current sample n is denoted as k(n) and is defined as k(n)=1·

p(n).

2. The gyroscope-based device of claim 1, wherein said computation of involuntary movement is a determination of the amount of hand jitter being currently experienced by said gyroscope-based device, and said value of said variable hand jitter compensation factor is directly proportional to the determined amount of hand jitter being currently experienced by said gyroscope-based device.

3. The gyroscope-based device of claim 2, further having a predefined number of fixed hand jitter compensation values and the same predefined number of hand jitter value ranges in a one-to-one correspondence;

and

said gyroscope-based device identifies the hand jitter value range within which the determined amount of hand jitter being currently experienced resides, and assigns the fixed hand jitter compensation value corresponding to the identified hand jitter value range to said variable hand jitter compensation factor.

4. The gyroscope-based device of claim 3, wherein:

said predefined number of fixed hand jitter compensation values is set to three corresponding to three hand jitter value ranges, said three hand jitter value ranges defining a “

small hand jitter user style”

range for the lowest hand jitter range, a “

normal hand jitter user style”

range for the intermediate hand jitter range, and a “

big hand jitter user style”

range for the highest hand jitter range, and

the hand jitter style range of the gyroscope-based device is continuously monitored, and a determination of whether the gyroscope-based device is being operated in the “

small hand jitter user style”

, the “

normal hand jitter user style”

, or “

big hand jitter user style”

is continuously updated; and

the fixed hand jitter compensation value corresponding to said “

big hand jitter user style”

is greater than the fixed hand jitter compensation value corresponding to said “

normal hand jitter user style”

, which in turn is greater than the fixed hand jitter compensation value corresponding to said “

small hand jitter user style”

.

5. The gyroscope-based device of claim 3, wherein the determined amount of hand jitter being currently experienced is determined by comparing the gyroscope-based device'"'"'s current movements along a given axis with similar movements in its immediate past along the same axis.

6. The gyroscope-based device of claim 1, wherein said probability processing unit implements a static-condition model defined as:

7. The gyroscope-based device of claim 6, wherein said immediate history period is fixed and set to the immediate 500 samples of said digitized gyroscope sensor data.

8. The gyroscope-based device of claim 6, wherein probability parameters σ

_v, σ

_m and σ

<sub>ω

′</sub>

, have values of 1 dps, 0.3 dps, and 3 dps, respectively.

9. The gyroscope-based device of claim 6, wherein variance v(n) and mean m(n) are determined for a period T defined by 30 samples of said digitized gyroscope sensor data.

10. The gyroscope-based device of claim 9, wherein variance v(n) is defined as:

11. The gyroscope-based device of claim 10, wherein samples n of said digitized gyroscope sensor data are provided at a rate of 100 Hz, and period T 300 milliseconds.

12. The gyroscope-based device of claim 1, further comprising a first memory for storing a history of past G_New(n) values determined from previous samples of said digitized gyroscope sensor data, said first memory being coupled to said probability processing unit.

13. The gyroscope-based device of claim 6, wherein said current compensation offset for the current sample n of said digitized gyroscope sensor data is denoted as b(n), and is defined as:

b(n)=(k(n)×

ω

′

(n)×

p(n))+(b_—

p(n)×

(1−

p(n)))

where b_p(n) is a prediction value based on a moving average over a fixed period defined by a fixed number of a number of samplings M in an immediate history of past b(n) values, b_p(n) being defined as;

14. The gyroscope-based device of claim 13, wherein said estimated compensation b′

is defined as b′

=b(n−

1).

15. The gyroscope-based device of claim 13, further comprising a second memory for storing a history of past b(n) values determined from previous samples of said digitized gyroscope sensor data, said second memory being coupled to said first summation node.

16. The gyroscope-based device of claim 14, wherein said first summation node receives b′

and G_Corr(n).

17. The gyroscope-based device of claim 14, wherein said first summation node received b(n) and G_Corr(n).

18. The gyroscope-based device of claim 6, wherein a current compensation offset b is determined for each current sample n of said digitized gyroscope sensor data, and estimated compensation offset b′

is set to the compensation offset b determined in the immediately previous cycle.