Human/Machine Interface for Using the Geometric Degrees of Freedom of the Vocal Tract as an Input Signal
A human/machine (HM) interface that enables a human operator to control a corresponding machine using the geometric degrees of freedom of the operator's vocal tract, for example, using the tongue as a virtual joystick. In one embodiment, the HM interface has an acoustic sensor configured to monitor, in real time, the geometry of the operator's vocal tract using acoustic reflectometry. A signal processor analyzes the reflected acoustic signals detected by the acoustic sensor, e.g., using signal-feature selection and quantification, and translates these signals into commands and/or instructions for the machine. Both continuous changes in the machine's operating parameters and discrete changes in the machine's operating configuration and/or state can advantageously be implemented.
1 . An apparatus, comprising:
an acoustic sensor adapted to direct bursts of acoustic waves toward a vocal tract of an operator and detect echo signals corresponding to the bursts; and
a processor operatively coupled to the acoustic sensor and configured to generate a control signal that enables operational control of a machine based on the detected echo signals.
2 . The apparatus of claim 1 , wherein the processor is configured to:
characterize a geometric configuration of the vocal tract based on the detected echo signals; and
generate the control signal based on said characterization.
3 . The apparatus of claim 1 , wherein the processor is configured to:
process the detected echo signals to determine an impulse response of the vocal tract; and
generate the control signal based on the impulse response.
4 . The apparatus of claim 1 , wherein the processor is configured to:
quantify one or more features of a detected echo signal; and
generate the control signal based on said quantification.
5 . The apparatus of claim 4 , wherein the one or more features comprise one or more of (i) a delay between a burst of acoustic waves and a corresponding echo signal, (ii) an amplitude of an echo signal, (iii) a phase of an echo signal, and (iv) a frequency spectrum of an echo signal.
6 . The apparatus of claim 1 , wherein the processor is configured to generate the control signal in a manner that enables a continuous change of an operating parameter for the machine.
7 . The apparatus of claim 1 , wherein the processor is configured to generate the control signal in a manner that enables a discrete change in an operating configuration or state of the machine.
8 . The apparatus of claim 1 , wherein the processor is configured to generate the control signal that causes at least a part of the machine to move or change a direction or speed of motion.
9 . The apparatus of claim 1 , wherein the acoustic sensor comprises an array of microphones configured to concurrently detect a plurality of echo signals.
10 . The apparatus of claim 9 , wherein the processor is configured to:
quantify a differential echo signal corresponding to a pair of said microphones; and
generate the control signal based on said quantification.
11 . The apparatus of claim 1 , wherein the processor is configured to generate the control signal in a manner responsive to motion of the operator's tongue.
12 . The apparatus of claim 1 , wherein the apparatus is configured to provide a feedback signal that prompts the operator to change a geometric configuration of the vocal tract.
13 . The apparatus of claim 12 , wherein:
the feedback signal comprises at least one of an audio signal and a video signal; and
the apparatus further comprises at least one of an earpiece configured to play said audio signal and a display screen configured to display said video signal.
14 . The apparatus of claim 1 , further comprising said machine.
15 . The apparatus of claim 1 , further comprising a video camera, wherein the processor is configured to:
determine a position of the acoustic sensor with respect to the vocal tract based on an image captured by the video camera; and
process the detected echo signals to generate the control signal while taking into account the determined position.
16 . The apparatus of claim 1 , further comprising a pair of wireless transceivers, wherein the processor is operatively coupled to the acoustic sensor via a wireless communication link established between the wireless transmitters of said pair.
17 . A method of operating a machine using a human/machine interface, the method comprising:
directing bursts of acoustic waves toward a vocal tract of an operator of the human/machine interface;
detecting echo signals corresponding to the bursts; and
generating a control signal that enables operational control of the machine based on the detected echo signals.
18 . The method of claim 17 , wherein the step of generating comprises:
processing the detected echo signals to determine an impulse response of the vocal tract; and
generating the control signal based on the impulse response.
19 . The method of claim 17 , wherein the step of generating comprises:
quantifying one or more features of a detected echo signal; and
generating the control signal based on said quantification.
20 . The method of claim 17 , wherein the step of generating comprises generating the control signal in a manner responsive to motion of the operator's tongue.