Abstract:
An electronic device for analyzing signal content derived from audible events, the device aiding the hearing impaired by annunciating events of interest including dangerous events. The device detects the presence of an event of interest by comparing characteristics of detected acoustic events with pre-determined reference characteristics, provides non-audible annunciators to indicate the presence of an event of interest, the type of event, and the direction from which the event is detected.

Description:
PRIORITY CLAIM AND INCORPORATION BY REFERENCE 
     This patent application claims the benefit of U.S. Prov. Pat. App. No. 61/014,013 filed Dec. 14, 2007. 
     U.S. Pat. Nos. 6,240,392, 6,219,643, 6,173,074, and 6,119,087 are incorporated herein by reference. U.S. Pat. App. No. 60/091,047 and U.S. Pat. Pub. No. 2006-0149552 A1 are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an electronic device utilizing one or more of signal analysis and signal filters for aiding the hearing impaired. 
     SUMMARY OF THE INVENTION 
     In the present invention an acoustically triggered non-audible annunciator for the hearing impaired comprises an intermediate block in signal communication with each of an acoustic to electric device and a non-audible annunciator. A first electrical signal is produced by the acoustic to electric device in response to an acoustic emission from an acoustic source. A second electrical signal is derived from the first electrical signal and the second electrical signal is indicative of at least a portion of the frequency content of the first signal. In various embodiments, in a plurality of reference bands, each reference frequency band is indicative of the nature of at least one acoustic source and there is a means for comparing the second electrical signal to each of the reference frequency bands. In some embodiments the intermediate block causes operation of the non-audible annunciator when a reference frequency band bears a pre-determined relationship to the frequency content of the first signal. 
     In an embodiment, a sound triangulator utilizes signals from a plurality of acoustic to electric devices to obtain an indication of a relative position of an acoustic source whose acoustic emission caused operation of a non-audible annunciator. 
     In an embodiment operation of a first annunciator alerts a hearing impaired person to assess the status of a second annunciator indicating the nature of the acoustic source and a third annunciator indication the direction of the acoustic source. 
     In an embodiment the assessor element includes a plurality of analog band-pass filters each band pass filter coupled to the electrical output of the acoustic to electric device. 
     In an embodiment the comparison element includes a plurality of analog comparators, each comparator coupled to a) an output of a respecitive band pass filter for receiving a signal in a pre-determined frequency band, b) a respective reference source for receiving a reference characteristic and c) a particular non-audible annunciator for operating the annunciator. 
     In an embodiment each of the band pass filters is tuned to a different frequency band and a respective reference characteristic is a pre-determined signal strength. 
     In an embodiment the assessor element and the comparison element include one or more digital signal processors coupled to a) the electrical output of the acoustic to electric device, b) a plurality of reference sources for receiving a plurality of reference characteristics, and c) a plurality of non-audible annunciators for operating one or more of the annunciators. 
     In an embodiment a signal from the output of the acoustic to electric device is transformed into the frequency domain to provide a derived acoustic signature of the acoustic source. 
     In an embodiment an annunciator is operated when the derived acoustic signature bears a pre-determined relationship with a reference acoustic signature. 
     In an embodiment a reference characteristic is a frequency band and frequency peaks in the derived acoustic signature falling within the reference frequency band cause operation of a particular non-audible annunciator. 
     And, in an embodiment a digital signal processor is used in deriving the acoustic signature from the output of the acoustic to electric device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is described with reference to the accompanying figures. These figures, incorporated herein and forming part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art to make and use the invention. 
         FIG. 1  is a block diagram of a device for the hearing impaired in accordance with the present invention. 
         FIG. 2  is block diagram of an intermediate block of the device for the hearing impaired of  FIG. 1 . 
         FIG. 3  is a diagram of a signal processed in a band pass filter of the device for the hearing impaired of  FIG. 1 . 
       FIGS.  4 A,B are diagrams indicative of an output signal of an acoustic to electric device of the device for the hearing impaired of  FIG. 1 . 
         FIG. 5  is a block diagram of a reference element of the device for the hearing impaired of  FIG. 1 . 
         FIG. 6  is a block diagram of a multiple acoustic to electric device version of the device for the hearing impaired of  FIG. 1 . 
         FIG. 7  is a block diagram of a multi-annunciator embodiment of the device for the hearing impaired of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a block diagram  100  in accordance with present invention. An intermediate block  104  receives signals from an acoustic to electric device  102  and an annunciator block  106  receives signals from the intermediate block. One or a plurality of signal paths  108  interconnect the acoustic to electric device and one or a plurality of signal paths interconnect the intermediate block and the annunciator block. As those of ordinary skill in the art will recognize, the described signal paths may be one or more of electric conductors, optical conductors or another medium capable of propagating a signal such as an atmosphere useful for propagating ultrasonic signals or radio waves. 
     The intermediate block  104  signals the annunciator block to operate one or more annunciators when the acoustic to electric device is excited by one or more particular acoustic sources  112 . For example,  FIG. 2  shows a block diagram  200  of an intermediate block. Included in this intermediate block are assessor  202 , comparison  204  and reference  206  elements. 
     The assessor element  202  is operable to assess one or more characteristics of the electrical output of the acoustic to electric device (the “S 1  signal”). In an embodiment, the assessor element assesses one or more characteristics of the electrical output of the acoustic to electric device in a particular frequency band, such as a pre-determined frequency band. 
     In an embodiment, the assessor element  202  incorporates an analog filter such as a band pass filter for isolating particular content S 2  of the signal S 1 . As shown in  FIG. 3 , the band pass filter attenuates the input signal outside a pass-band centered on a selected center frequency “C.” In some embodiments, the assessor element incorporates multiple band-pass filters, each centered on a different frequency for assessing characteristics in a one of a plurality of frequency bands. 
     Capable of isolating multiple frequency peaks present in a signal, digital signal analyzers and/or filters may be used by the assessor element  202  to assess characteristics of signal S 1 . In an embodiment, the assessor element  202  incorporates spectral analysis such as Fourier Transform analysis for determining the particular frequency content S 2  of the signal S 1 . The assessor element assesses characteristics in one or a plurality of frequency bands. In an embodiment, the assessor element  202  incorporates a digital filter such as a filter implementing a Fourier Transform. 
     As shown in  FIG. 4   a , a time-domain signal plot  400   a , the signal S 1  may be a complex signal including many different frequency components. When this signal is processed by a Fourier Transform filter, the output appears as shown in the frequency-domain plot  400   b  of  FIG. 4   b ; here, there are one or more peaks representing the frequencies at which the strongest signals occur. The signal peaks, such as voltage peaks, indicate the predominant frequencies present in the signal S 1 . 
     Still other devices may be used to enable the assessor element  202  to evaluate characteristics of the signal S 1 . For example,  FIG. 7  shows an embodiment  700  of the present invention wherein a digital signal processor  704  receives signals from one or a plurality of acoustic to electric devices  102   a - c  via respective optional filter/amplifiers  702   a - c . In this configuration, the DSP is used to evaluate characteristics of the signal S 1 . Digital signal processors useful for this purpose include general purpose DSP&#39;s and in particular, Texas Instrument&#39;s TMS320VC5507-200. 
     In an embodiment, the pre-determined frequency band is the frequency band audible to humans, including frequencies from about 20 Hz to 20,000 Hz. In other embodiments, the pre-determined frequency band is a smaller portion of this audible frequency band, such as a 450 Hz to 550 Hz band centered on a commonly used 500 Hz siren frequency. 
       FIG. 5  shows a block diagram of a reference element  500 . Here, a reference element  206  includes one or more reference sources  302  for providing respective reference characteristics  304 , each reference characteristic being indicative of an audible event calling for an immediate action, such as an immediate human action. Reference characteristics include acoustic signatures for comparison with acoustic signatures isolated from signals received from acoustic to electric device(s)  102 . 
     The reference element may be implemented in analog form, such as resistors of given values used to produce given voltages or currents as reference values, or in digital form such as in digital memory accessible to a digital processor. As shown in the embodiment of  FIG. 7 , a digital signal processor  704  receives the signal S 1  to assess a particular characteristic of the signal. In an embodiment, the DSP is in communication with a digital memory device  707  in which one or a plurality reference values are stored. 
     Comparison of an output of the assessor element  202  with a respective reference characteristic  504  occurs in the comparison element  204 . The comparison element is operable to cause operation of a particular one or combination of non-audible annunciators  106   a - c  when in the pre-determined frequency band at least one characteristic of the signal S 1  bears a pre-determined relationship with a reference characteristic. 
     In an embodiment, the comparison element  204  compares the strength of an audio signal in the electric output of the acoustic to electric device with a reference signal strength. When the audio signal strength bears a pre-determined relationship with the reference signal strength, an element of the intermediate block such as the comparison element causes operation of a particular non-audible annunciator. In some embodiments, it is the audio signal in a particular frequency band that is compared with a reference signal strength. For example, in an embodiment the presence of a particular frequency component in the signal S 1  causes operation of a particular annunciator when the energy at that frequency as indicated by voltage, amplitude or other indicia known to those of ordinary skill in the art exceeds a reference value. In other embodiments, one or more specific frequencies and/or amplitudes are compared with reference frequencies and/or amplitudes. 
     As persons of ordinary skill in the art will understand, an acoustic to electric device  102  having a digital output  108  may be used in the present invention. In this case, a digital interface of the intermediate block  104  will receive the signal, such as a digital interface of the assessor element  202 . 
     In some embodiments, multiple acoustic to electric devices may be used to enable an indication of the position of an acoustic source  112  relative to one or more of the acoustic electric devices. For example,  FIG. 6  shows an embodiment of the present invention having three acoustic to electric devices. Here, the acoustic to electric devices  102   a - c  are spaced apart and respective output signals S 1   a - c  are responses to an acoustic emission  112 . A plurality of audio signals, in this case three, provides information about the location of the audio source relative to the acoustic to electric devices. Using three spaced apart acoustic to electric devices allows the direction and/or location of the acoustic emission relative to the acoustic electric devices to be approximated based on an estimated value of the speed of sound used in the following three equations: t 1 =d 1 /v, t 2 =d 2 /v and t 3 =d 3 /v. In each equation, the distance (d 1 , d 2 , d 3 ) can be determined since the respective times (t 1 , t 2 , t 3 ) and velocity are known. Assuming the acoustic to electric devices and the acoustic source lie in the same plane, there is a single point can be identified where circles of diameters d 1 , d 2  and d 3  with centers at the locations of the respective acoustic to electric devices have a common intersecting point. Moreover, even if multiple planes are involved, so long as the separation between the planes is small compared to the distance between the acoustic to electric devices and the acoustic source, a good approximation of the direction and distance is nevertheless obtained. 
     In various embodiments, the triangulation methods disclosed in one or more of U.S. Pat. Nos. 7,054,228 and 7,277,116 may be used alone or in conjunction with the methods described above. In an embodiment, a fourth acoustic to electric device such as a microphone (not shown) is used to enable identification of an acoustic source location in three dimensions. Here, one of the triangulation methods described above may be extended for this purpose or another methodology known in the art such as that of the Appendix to this application may be used for this purpose. 
     Referring again to  FIGS. 1 and 6 , an annunciator block  106  receives signals S 2  from the intermediate block  104 . In an embodiment, one of a plurality of non-audible annunciators  106   a - c  is operated by the intermediate block in response to an audible event calling for an immediate action, such as an immediate human action. 
     Referring again to  FIG. 7 , this embodiment shows a plurality of intermediate block drivers  710 ,  712 ,  714  for causing operation of respective annunciators  708 ,  716 ,  718  within an annunciator block  106  in response to signals from a digital signal processor  704 . A driver such as an alert driver  714  operates a tactile exciter such as a vibrator or a vibrating alert device  708 . In an embodiment, a tactile exciter serves to get a person&#39;s attention, causing the person to examine other information made available by the present invention. A driver such as a radial display driver  712  operates a direction indicating display such as a radial display  718 . In some embodiments, the radial display includes an alphanumeric display. As was discussed above, some embodiments include direction and distance sensing features which is displayed in various embodiments on a radial display and/or a conventional alphanumeric display. 
     A driver such as a significance display driver  710  operates a selected one or more of a plurality of illuminating devices such as lamps or light emitting diodes  716 . As was discussed above, various characteristics of a signal S 1  can be obtained by analyzing the signal and a subsequent comparison of the signal characteristic with a reference value used for operating an annunciator indicating for example the occurrence of a particular event or the proximity of a particular acoustic source such as traffic, train, horn, voice, tire squeal, alarm, siren, panic noise and the like. Exemplary luminary annunciators include annunciators for police, ambulance, fire, tire screech, train, automobile horn, cry, scream, name, phone and door or door bell. For example, a signal S 1  containing a peak at 500 Hz in the frequency domain may be indicative of a police siren and if so, would in an embodiment cause the operation of the police luminary annunciator of the annuniciator  716 . 
     In operation, one or a plurality of characteristics are searched for in the signal S 1 . For example, multiple band pass filters may be used or a Fourier Transform may be implemented in a digital filter of the intermediate block  104 . In an embodiment, a broad spectrum filter or no filter (the alert filter) is used merely to sense the occurrence of a loud noise. In addition, in a similar manner and/or as described above, characteristics of the signal such as signal component amplitudes at frequencies of interest are determined. In some embodiments multiple acoustic to electric devices  102   a - c  are used to provide a relative direction and distance to the acoustic source. 
     When the signal from the alert filter exceeds a respective reference value  304 , the tactile exciter is operated to get the attention of a person using the present invention. The attending person then looks at one or more of a radial display and a panel of luminary annunciators  716  to determine the relative location and the nature of the of the acoustic emission. In this manner, users of the present invention are provided with notice and/or warning of proximate acoustic events. 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to those skilled in the art that various changes in the form and details can be made without departing from the spirit and scope of the invention. As such, the breadth and scope of the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and equivalents thereof.