Horn Input to In-Vehicle Devices and Systems
The present application provides a system, method and non-transitory computer readable medium that provides a means of using a vehicle horn as an inexpensive user input interface to serve the function of a simple push button switch for an in-vehicle device or system. The use of the vehicle horn as a user input interface to an in-vehicle device or system is novel. The description of example embodiments illustrates application details that take advantage of the properties of the vehicle horn sound to allow efficient processing that can be implemented on a low cost processor.
1 . A method comprising:
recording a sound signal in memory, the sound signal responsive to generating a prompt;
computing a power spectral density of the sound signal;
determining a sound start-up point and a sound drop-off point of the sound signal based on signal power identified from the computed power spectral density;
utilizing a plurality of components of the power spectral density of the sound signal between the sound start-up point and the sound drop-off point to create a set of sound calibration parameters; and
processing subsequent sound signals with the sound calibration parameters to determine if they are comparable to the sound signal.
2 . The method of claim 1 , wherein the power spectral density is computed by using a fast Fourier transform (FFT) performed on the sound signal.
3 . The method of claim 1 , wherein the sound signal is a motor vehicle horn sound that is recorded for a predetermined amount of time.
4 . The method of claim 1 , further comprising:
identifying a frequency and an amplitude of M largest tones of the sound signal, the M largest tones identified as being a predefined number of sound signal components above a predetermined fundamental low frequency; and
designating the M largest tones as horn identification calibration parameters.
5 . The method of claim 4 , further comprising measuring the frequency and the amplitude of the M largest tones of the sound signal for a predetermined number of times per second over a predefined time frame.
6 . The method of claim 5 , wherein the predetermined number of times per second is two times per second and the predefined time frame is four seconds.
7 . The method of claim 2 , further comprising:
comparing a sequence of detection statistics to a predetermined detection threshold; and
determining whether the motor vehicle horn sound is on or off based on the comparison.
8 . An apparatus comprising:
a memory configured to record a sound signal, the sound signal responsive to a prompt being generated;
a processor configured to
compute a power spectral density of the sound signal,
determine a sound start-up point and a sound drop-off point of the sound signal based on signal power identified from the computed power spectral density,
utilize a plurality of components of the power spectral density of the sound signal between the sound start-up points and sound drop-off point to create a set of sound calibration parameters, and
process subsequent sound signals with the sound calibration parameters to determine if they are comparable to the sound signal.
9 . The apparatus of claim 8 , wherein the power spectral density is computed by using a fast Fourier transform (FFT) performed on the sound signal.
10 . The apparatus of claim 8 , wherein the sound signal is a motor vehicle horn sound that is recorded for a predetermined amount of time.
11 . The apparatus of claim 8 , wherein the processor is further configured to identify a frequency and an amplitude of M largest tones of the sound signal, the M largest tones identified as being a predefined number of sound signal components above a predetermined fundamental low frequency, and designate the M largest tones as horn identification calibration parameters.
12 . The apparatus of claim 11 , wherein the processor is further configured to measure the frequency and the amplitude of the M largest tones of the sound signal for a predetermined number of times per second over a predefined time frame.
13 . The apparatus of claim 12 , wherein the predetermined number of times per second is two times per second and the predefined time frame is four seconds.
14 . The apparatus of claim 9 , wherein the processor is further configured to compare a sequence of detection statistics to a predetermined detection threshold, and determine whether the motor vehicle horn sound is on or off based on the comparison.
15 . A non-transitory computer readable storage medium configured to store instructions that when executed cause a processor to perform:
recording a sound signal in memory, the sound signal responsive to generating a prompt;
computing a power spectral density of the sound signal;
determining a sound start-up point and a sound drop-off point of the sound signal based on signal power identified from the computed power spectral density;
utilizing a plurality of components of the power spectral density of the sound signal between the sound start-up point and the sound drop-off point to create a set of sound calibration parameters; and
process subsequent sound signals with the sound calibration parameters to determine if they are comparable to the sound signal.
16 . The non-transitory computer readable storage medium of claim 15 , wherein the power spectral density is computed by using a fast Fourier transform (FFT) performed on the sound signal.
17 . The non-transitory computer readable storage medium of claim 15 , wherein the sound signal is a motor vehicle horn sound that is recorded for a predetermined amount of time.
18 . The non-transitory computer readable storage medium of claim 15 , wherein the processor is further configured to perform:
identifying a frequency and an amplitude of M largest tones of the sound signal, the M largest tones identified as being a predefined number of sound signal components above a predetermined fundamental low frequency; and
designating the M largest tones as horn identification calibration parameters.
19 . The non-transitory computer readable storage medium of claim 18 , wherein the processor is further configured to perform measuring the frequency and the amplitude of the M largest tones of the sound signal for a predetermined number of times per second over a predefined time frame.
20 . The non-transitory computer readable storage medium of claim 19 , wherein the predetermined number of times per second is two times per second and the predefined time frame is four seconds.