Methods, apparatus and systems using motion of various input devices for controlling consumer devices
Method, apparatus, and systems for roll angle estimation for an input/gesture device (IGD) are disclosed. The method includes estimating a first axis vector of the input/gesture device (IGD) relative to the surface of the mobile device (MD), as a first frame of reference, using readings from a first type of sensor; and estimating the first axis vector of the IDG relative to a different, second frame of reference using a gyroscope integration of readings from the 3-axis gyroscope. The method further includes aligning the first axis vector of the IDG in the first frame of reference with the first axis vector of the IDG in the second frame of reference; minimizing a change in the alignment of the first axis vectors between the first frame of reference and the second frame of reference; and determining the roll angle of the IDG relative to the surface of the MD.
1. A method of roll angle estimation for an input/gesture device having a 3-axis gyroscope, as a first type of motion sensor, and a 3-axis accelerometer, as a second type of motion sensor, the input/gesture device being in communication with a mobile device having a surface, the method comprising:
measuring 3D linear motion or obtaining measurements of the 3D linear motion of the input/gesture device based on reading from the 3-axis accelerometer and the 3-axis gyroscope of the input/gesture device;
measuring 2D planar linear motion or obtaining measurements of the 2D planar linear motion of the input/gesture device based on reading from a third type of sensor;
correlating the 3D linear motion with the 2D planar linear motion; and
determining the roll angle of the input/gesture device relative to the surface of the mobile device by solving for frame alignment between an inertial frame and a mobile device frame using a result of the correlating step,
wherein the step of determining the roll angle further comprises:
applying a rigid body formula to estimate an acceleration of the tip of input/gesture device, rather than a location of the 3-axis accelerometer;
representing the 2D planar linear motion coordinates of the tip in 3D;
applying a DC-blocking filter on both a 3D pointer trajectory from the surface and double integrated 3-axis accelerometer data to generate two signals; and
determining a frame alignment that aligns the two signals.
2. The method of claim 1 , wherein the input/gesture device is a pen or stylus and wherein the mobile device is a tablet.
3. The method of claim 1 further comprising:
using the determined roll angle of the input/gesture device to modify an input from the input/gesture device to the mobile device.
4. The method of claim 1 , wherein the third type of sensor is an electromagnetic (EM) sensor.
5. An input/gesture device comprising:
a sensor;
a 3-axis gyroscope;
a 3-axis accelerometer; and
a processor configured to:
measure 3D linear motion or obtaining measurements of the 3D linear motion of the input/gesture device based on reading from the 3-axis accelerometer and the 3-axis gyroscope of the input/gesture device;
measure 2D planar linear motion or obtaining measurements of the 2D planar linear motion of the input/gesture device based on reading from a third type of sensor;
correlate the 3D linear motion with the 2D planar linear motion; and
determine the roll angle of the input/gesture device relative to the surface of the mobile device by solving for frame alignment between an inertial frame and a mobile device frame using a result of the correlate step,
wherein the processor is further configured to perform the determine step by:
applying a rigid body formula to estimate an acceleration of the tip of input/gesture device, rather than a location of the 3-axis accelerometer;
representing the 2D planar linear motion coordinates of the tip in 3D;
if a size of the surface is known, applying scaling to convert from pixels to distance;
applying a DC-blocking filter on both a 3D pointer trajectory from the surface and double integrated 3-axis accelerometer data to generate two signals; and
determining a frame alignment that aligns the two signals.
6. The input/gesture device of claim 5 , wherein the input/gesture device is a pen or stylus.
7. The input/gesture device of claim 5 wherein the processor is further configured to use the determined roll angle of the input/gesture device to modify an input from the input/gesture device to the mobile device.
8. The input/gesture device of claim 5 , wherein the third type of sensor is an electromagnetic (EM) sensor.