Hybrid inertial and touch sensing input device
A method and apparatus for tracking coarse and fine motions associated with an electronic input device is disclosed. The electronic input device can have both an inertial sensor and a touch sensor. The method includes receiving inputs from an inertial sensor and a touch sensor, and dynamically adjusting a velocity estimate of the electronic input device based on weighting or predetermined thresholds of the inputs to maximize a tracking range of the input device.
1. A method for using inertial inputs and touch inputs of an electronic input device, the method comprising:
receiving a motion input from a motion sensor, the motion sensor configured to sense movement of the electronic input device;
calculating a first estimated velocity (Va) based on the motion input, the first estimated velocity indicative of a velocity of the movement of the electronic input device;
receiving a touch input from a touch sensor, the touch sensor configured to sense a user interaction with a surface of the electronic input device;
calculating a second estimated velocity (Vt) based on the touch input, the second estimated velocity indicative of a velocity of the user interaction with the surface of the electronic input device;
determining a first weight (Wa) associated with the motion input and a second weight (Wt) associated with the touch input, determining the first weight (Wa) includes factoring in a selected crossover velocity (Vc), the crossover velocity (Vc) defines a threshold where the first weight (Wa) or the second weight (Wt) becomes more significant; and
calculating a motion output (V) based on the first (Wa) and the second (Wt) weights, according to the formula V=Wa*Va+Wt*Vt.
2. The method of claim 1 , wherein the first weight is calculated based on a root mean square value of the first estimated velocity (Va).
3. The method of claim 1 , wherein the second weight is calculated based on a root mean square value of the second estimated velocity (Vt).
4. The method of claim 1 , wherein the first weight is calculated based on the following relationship:
Wa
=
max
(
V
a
V
c
,
1
)
.
5. The method of claim 4 , wherein the second weight is calculated based on the following relationship:
Wt= 1− Wa.
6. An electronic input device, comprising:
a motion sensing element operable to measure a motion of the electronic input device to obtain a motion input;
a touch sensing element operable to measure a touch motion on the electronic input device to obtain a touch input, the touch sensing element configured to sense a user interaction with a surface of the electronic input device;
a processing element operable to:
calculate a first estimated velocity (Va) based on the motion input, the first estimated velocity indicative of a velocity of the movement of the electronic input device;
calculate a second estimated velocity (Vt) based on the touch input, the second estimated velocity indicative of a velocity of the user interaction with the surface of the electronic input device;
determine a first weight (Wa) associated with the motion input and a second weight (Wt) associated with the touch input, determining the first weight (Wa) includes factoring in a chosen velocity for crossover (Vc), the crossover velocity (Vc) defines a threshold where the first weight (Wa) or the second weight (Wt) becomes more significant; and
calculate an output (V) based on the first (Wa) and the second (Wt) weights, according to the formula V=Wa*Va+Wt*Vt; and
an interface operable to send the output to an external device.
7. The device of claim 6 , wherein the first weight is calculated based on a root mean square value of the first estimated velocity (Va).
8. The device of claim 6 , wherein the second weight is calculated based on a root mean square value of the second estimated velocity (Vt).
9. The device of claim 6 , wherein the first weight is calculated based on the following relationship:
Wa
=
max
(
V
a
V
c
,
1
)
.
10. The device of claim 9 , wherein the second weight is calculated based on the following relationship:
Wt= 1− Wa.
11. A tangible computer-readable storage device for an electronic input device, including program code for:
receiving a motion input from a motion sensor, the motion sensor configured to sense movement of the electronic input device;
calculating a first estimated velocity (Va) based on the motion input, the first estimated velocity indicative of a velocity of the movement of the electronic input device;
receiving a touch input from a touch sensor, the touch sensor configured to sense a user interaction with a surface of the electronic input device;
calculating a second estimated velocity (Vt) based on the touch input, the second estimated velocity indicative of a velocity of the user interaction with the surface of the electronic input device;
determining a first weight (Wa) associated with the motion input and a second weight (Wt) associated with the touch input, determining the first weight (Wa) includes factoring in a selected crossover velocity (Vc), the crossover velocity (Vc) defines a threshold where the first weight (Wa) or the second weight (Wt) becomes more significant; and
calculating a motion output (V) based on the first (Wa) and the second (Wt) weights, according to the formula V=Wa*Va+Wt*Vt.
12. The tangible computer-readable storage device of claim 11 , wherein the first weight is calculated based on the following relationship:
Wa
=
max
(
V
a
V
c
,
1
)
.
13. The tangible computer-readable storage device of claim 12 , wherein the second weight is calculated based on the following relationship:
Wt= 1− Wa,
where Wa is the first weight, and Wt is the second weight.
14. The tangible computer-readable storage device of claim 11 , wherein the first weight is calculated based on a root mean square value of the first estimated velocity (Va).
15. The tangible computer-readable storage device of claim 11 , wherein the second weight is calculated based on a root mean square value of the second estimated velocity (Vt).