Minimizing unwanted responses in haptic systems
Disclosed are methods to manipulate a given parametrized haptic curve in order to yield a smooth phase function for each acoustic transducer which minimizes unwanted parametric audio. Further, the impulse response of a haptic system describes the behavior of the system over time and can be convolved with a given input to simulate a response to that input. To produce a specific response, a deconvolution with the impulse response is necessary to generate an input.
1. A method comprising:
creating haptic feedback using ultrasound comprising the steps of:
producing an acoustic field from a transducer array having known relative positions and orientations;
defining a focus point having a known spatial relationship relative to the transducer array defining a path having a known spatial relationship relative to the transducer array in which the focus point will translate;
moving the focus point near the path so as to produce little audible sound.
2. The method as in claim 1 , further comprising:
moving the focus point near the path in a method selected to produce a smooth phase function for a transducer.
3. The method as in claim 1 wherein the focus point moves near the path to produce a phase function with reduced high-frequency content for a transducer.
4. The method as in claim 1 , wherein the focus point moves near the path so as to produce a smooth radius versus time from a transducer.
5. The method as in claim 1 , wherein the focus point moves so that it spends more time near locations in the curve with tight curvature or end points.
6. The method as in claim, 1 wherein the path is subdivided into multiple focal points.
7. The method as in claim 6 , wherein the multiple focal points are distributed along the path to produce a smooth phase function for a transducer.
8. The method as in claim 6 , wherein the multiple focal points are distributed along the path to produce a phase function with reduced high-frequency content for a transducer.
9. The method as in claim 6 , wherein the multiple focal points are distributed along the path so as to produce a smooth radius versus time from a transducer.
10. The method as in claim 6 , wherein the multiple focal points are distributed along the path such that the multiple focal points are more closely distributed at locations with tight curvature or end points.
11. The method as in claim 6 , wherein spatial locations of the multiple focal points are filtered to remove high-frequency content.
12. The method as in claim 1 , wherein the path also has a third path dimension, and wherein the approximation function individually filters in the first path dimension, in the second path dimension, and in the third path dimension.
13. The method as in claim 1 , wherein the approximation function uses an infinite impulse response filter.
14. The method as in claim 1 , wherein the approximation function uses an finite impulse response filter.