Abstract:
A communication apparatus comprising an audio input device adapted to capture a first audio sample, where the first audio sample comprises a noise component. The apparatus further comprises signal processing logic coupled to the audio input device. If the intensity of the noise component is equal to or greater than the intensity of a voice component of a second audio sample received from a different communication apparatus, the signal processing logic amplifies the voice component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a non-provisional application claiming priority to EP Application Serial No. 06290181.4 filed on Jan. 27, 2006, entitled “Voice Amplification Apparatus,” which is hereby incorporated by reference.  
       BACKGROUND  
       [0002]     The Lombard Effect is the tendency for a person to increase vocal intensity in response to background noise such that the person&#39;s voice can be heard over the background noise, For example, the Lombard Effect is often observed in people participating in face-to-face conversations that occur in noisy environments. Use of the Lombard Effect by a person generally depends on the person&#39;s recognition that in order to be heard, he or she must increase his or her vocal intensity above that of the background noise.  
         [0003]     In some situations, however, the person is unable to appreciate the need for increased vocal intensity. For example, during a telephone conversation, person “A” may speak with person “B,” where persons A and B are in different environments. Person A may be in a quiet environment, such as an office, whereas person B may be in a noisy environment, such as a busy street. Because Person A is in a quiet environment, he or she may not appreciate the need to speak with increased vocal intensity so that his or her voice can be heard by Person B. Thus, Person B may have difficulty hearing Person A.  
       BRIEF SUMMARY  
       [0004]     Disclosed herein is a device and method by which voice signals are selectively amplified to make the voice signals audible over noise signals An illustrative embodiment includes a communication apparatus comprising an audio input device adapted to capture a first audio sample, where the first audio sample comprises a noise component. The apparatus further comprises signal processing logic coupled to the audio input device. If the intensity of the noise component is equal to or greater than the intensity of a voice component of a second audio sample received from a different communication apparatus, the signal processing logic amplifies the voice component.  
         [0005]     Yet another illustrative embodiment includes an apparatus comprising a processor adapted to receive a first audio signal having a noise component and a second audio signal having a voice component. The apparatus also comprises an amplifier coupled to the processor. The processor determines the difference in intensity between the noise and voice components If the difference is within a predetermined range, the amplifier amplifies the voice component.  
         [0006]     Yet another illustrative embodiment includes a method which comprises receiving a first audio sample having a voice component and a second audio sample having a noise component. The method also comprises determining the difference in intensity between the voice and noise components and, if the difference is below a predetermined threshold, amplifying the voice component until the difference meets or exceeds the predetermined threshold. The first and second audio samples are received from different communication devices.  
       Notation and Nomenclature  
       [0007]     Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, various companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections The term “intensity,” in at least some embodiments, refers to the decibel rating of a signal. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     For a more detailed description of the preferred embodiments of the present invention, reference will now be made to the accompanying drawings, wherein:  
         [0009]      FIG. 1  shows a pair of mobile devices communicating with each other in accordance with preferred embodiments of the invention;  
         [0010]      FIG. 2  shows another pair of mobile devices communicating with each other in accordance with embodiments of the invention;  
         [0011]      FIG. 3  shows a block diagram of signal processing circuitry contained in a mobile device of  FIG. 1 , in accordance with preferred embodiments of the invention; and  
         [0012]      FIG. 4  shows a flow diagram of a method used in accordance with embodiments of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]     The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims, unless otherwise specified. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.  
         [0014]     Disclosed herein is a device which receives a speech signal from another device and which determines whether the local background noise intensity (e.g., decibel rating) is greater than the intensity of the received signal. If the background noise intensity is greater than the speech intensity, the device amplifies (ie., applies the Lombard Effect to) the speech such that the speech intensity is greater than the background noise intensity. In this way, the speech is audible over the background noise. The device may be implemented, for instance, in mobile communication devices such as cellular telephones, combination cell phones/personal digital assistants (PDAs), land-line telephones, walkie-talkies, radios, and other suitable communication devices.  
         [0015]      FIG. 1  shows a communication device  100  in communication with a communication device  150 . The device  100  comprises a microphone  102 , a speaker  104 , an antenna  106 , a transceiver  107  and signal processing circuitry  108 . The device&#39;s signal processing circuitry  108  may comprise circuitry (shown in  FIG. 3 ) which enables the device  100  to communicate with the device  150 , For example, such circuitry may comprise a processor, memory and a power supply. Likewise, the device  150  comprises circuitry (e.g., antenna, transceiver) which enables the device  150  to communicate with the device  100 .  
         [0016]     Continuing with the example above, assume person A uses the device  150  in a quiet environment (e.g., an office) and person B uses the device  100  in a noisy environment (e.g., on a busy street). Person A speaks into the device  150 . The device  150  captures Person A&#39;s speech and converts the speech into digital signals which are subsequently modulated and broadcast to the antenna  106  of device  100 . In at least some embodiments, the wireless signals are encoded not only with the speech of Person A, but also with the background noise present in Person A&#39;s environment.  
         [0017]     The wireless signals transmitted by device  150  are received by device  100  via antenna  106 . The wireless signals received from device  150  are represented by arrows marked “A,” since device  150  is used by Person A. The signals represented by arrows “A” represent a continuous feed of data transmitted from device  150  to device  100  for a finite length of time. For instance, arrows A may represent a 15-minute continuous stream of audio data for a 15-minute telephone conversation between Persons A and B. The signals represented by arrows A comprise a series of audio samples. The audio samples may be of the same length or, in some embodiments, of different lengths. In at least some embodiments, the audio samples are on the order of several milliseconds. The signal processing circuitry  108  preferably processes one audio sample from signals A at a time.  
         [0018]     The signal processing circuitry  108  receives the audio samples via the antenna  106  and transceiver  107  (which demodulates the samples) and converts the digital signals to analog signals. As described in detail below, the circuitry  108  analyzes the audio samples to distinguish between Person A&#39;s voice and the background noise of Person A&#39;s environment. Having distinguished the portions of the audio samples which correspond to Person A&#39;s voice, the circuitry  108  determines whether any portion of the signals corresponding to Person A&#39;s voice should be amplified (ie., whether the Lombard Effect should be applied). Specifically, the circuitry  108  compares the intensity of Person A&#39;s voice to the intensity of the background noise of Person B&#39;s environment. As previously described, if the intensity of the background noise of Person B&#39;s environment is more intense than Person A&#39;s voice, Person B will be unable to hear Person A.  
         [0019]     Several milliseconds may elapse between the time an audio sample is transmitted from device  150  and the time at which the same audio sample reaches device  100 . The background noise of Person B&#39;s environment may change (e.g., become more intense) during this time period. For this reason, the above-mentioned comparison preferably is performed using the most current background noise data available. Specifically, the comparison preferably takes place between background noise encoded on audio samples captured by microphone  102  (indicated by arrows marked “B”) at or about the time that audio samples from device  150  are received by the circuitry  108 . In this way, the circuitry  108  is able to adjust the intensity of Person A&#39;s received voice samples based on the most current background noise intensity captured by microphone  102 . Conversely, although not preferred, it is possible to compare audio samples captured by microphone  102  at the same time that audio samples are captured by device  50 . Although within the scope of this disclosure, this technique is not preferred because by the time the audio samples from device  150  are received by the circuitry  108 , the background noise intensity data captured by microphone  102  may be outdated.  
         [0020]     If, while comparing audio samples from signals A and B, the circuitry  108  determines that a portion of signal B is encoded with background noise more intense than voice encoded on a corresponding portion of signal A, the circuitry  108  preferably amplifies Person A&#39;s received voice data such that the voice encoded on that portion of signals A is more intense (i.e., has a greater decibel rating) than the corresponding background noise encoded on signals B. In some embodiments, the circuitry  108  may amplify Person A&#39;s voice data until the intensity of the voice data exceeds a predetermined threshold, or until the intensity of the voice data falls within a desired, predetermined range of intensities, or until the intensity of the voice data falls outside of an undesired, predetermined range of intensities.  
         [0021]     The threshold and/or predetermined range(s) may be programmed into software stored in the circuitry  108 , and may be adjustable by a user. For instance, in some embodiments, a user may adjust the threshold and/or predetermined range(s) using software provided on the device  100 . In other embodiments, a wheel, button or other hardware feature (not specifically shown) may be used to adjust the threshold and/or predetermined range(s). In at least some embodiments, such a hardware feature may be dedicated solely to adjusting the threshold and/or predetermined range(s). The adjustment capability may be enabled or disabled as desired, possibly through software running on the device  100  or through a hardware feature provided on the device  100 . The signals output by the circuitry  108  to the speaker  104  (i.e., to a user of the device  100 ), regardless of whether the signals are amplified, are marked by arrow “A′.” The circuitry  108  may forward signals B from the microphone  102  to the antenna  106  for transmission.  
         [0022]      FIG. 1  illustrates the capability of the circuitry  108  to selectively amplify signals received from communication device  150 . However, in at least some embodiments, the device  150  may selectively amplify signals A before they are transmitted to the device  100 .  FIG. 2  shows the communication devices  100  and  150  of  FIG. 1 . The device  150  comprises a microphone  152 , a speaker  154 , an antenna  156 , a transceiver  157  and signal processing circuitry  158 . Signals B are transmitted from device  100  to the antenna  156  of device  150  and further to signal processing circuitry  158 . Like the circuitry  108 , the circuitry  158  first de-modulates the audio samples received via the antenna  156  (using transceiver  157 ) and converts the digital signals to analog signals. The circuitry  158  analyzes the audio samples to distinguish between Person B&#39;s voice and the background noise of Person B&#39;s environment. Having identified the portions of the audio samples which correspond to Person B&#39;s voice, the circuitry  158  determines whether any portion of the signals corresponding to Person A&#39;s voice should be amplified (i.e., whether the Lombard Effect should be applied) and acts accordingly.  
         [0023]     The circuitry  158  determines whether any portion of signals A should be amplified by comparing signals A and B as described above. In particular, the circuitry  158  compares the background noise encoded in signals B to the speech encoded in signals A. If the background noise in signals B is more intense than the speech encoded in signals A, the circuitry  158  may amplify one or more portions of signals A. Specifically, the circuitry  158  may amplify one or more portions of signals A until the speech encoded in signals A is audible over the corresponding background noise encoded in signals B. In the Figure, the signals transferred from circuitry  158  to transceiver  157  are marked as “A′” and comprise both adjusted (i.e., amplified) and non-adjusted signals. The signals A′ are transferred from the transceiver  157  to the antenna  156  for transmission to device  100 . In this way, the circuitry  158  selectively amplifies Person A&#39;s speech prior to transmission to device  100 . The circuitry  158  also may transfer signals B to the speaker  154 . The contents of the signal processing circuitry  108  and  158  are now described in detail.  
         [0024]      FIG. 3  shows a detailed view of the signal processing circuitry  108 . The components shown in  FIG. 3  also may be included in the circuitry  158 , since circuitry  108  and  158  are substantially similar to each othen. The circuitry  108  comprises a digital signal processor (DSP)  200 , which is a processor used to efficiently and rapidly perform signal processing calculations on digitized signals (e.g., voice signals). The circuitry  108  further comprises a memory  202  coupled to the DSP  200 . In at least some embodiments, the memory  202  comprises a read-only memory (ROM), and in other embodiments, the memory  202  comprises a combination of ROM and random-access memory (RAM). Although not specifically shown, the circuitry  108  may comprise various firewalls, security controllers, direct memory access (DMA) controllers, and/or other components which regulate access to the memory  202 . Various software applications may be stored on the memory  202  while being executed by the DSP  200 . The circuitry  108  may comprise an amplifier  218  used to amplify audio signals and a digital-to-analog (D/A) converter  216  to convert digital signals to analog signals. The circuitry  158  may further comprise various other devices, including a display  204 , an input keypad  206 , a vibrating device  208 , a battery  210  and/or a charge-couple device (CCD)/complementary metal oxide semiconductor (CMOS) camera. The DSP  200  may receive signals from and send signals to the antenna  106  via the transceiver  157 . The DSP  200  also may receive audio samples captured by microphone  102  and may output audio samples to speaker  104 . In at least some embodiments, some or all of the components shown in  FIG. 3  may be incorporated onto a single chip, known as a system-on-chip (“SoC”).  
         [0025]     In operation, the DSP  200  receives audio samples from the antenna  106  and the microphone  102 . Samples from the antenna  106  correspond to the voice and background noise of Person A and Person A&#39;s environment, respectively, and samples from the microphone  102  correspond to the voice and background noise of Person B and Person B&#39;s environment, respectively. Audio samples may vary in length (e.g., on the order of nanoseconds or milliseconds), The DSP  200  processes audio samples using signal processing software stored on the memory  202 . In particular, when executed, the software causes the DSP  200  to convert the digital signals A to analog form using D/A  216  and to conduct a spectral analysis of the audio samples so as to distinguish voice data from noise data encoded on the audio samples, Noise data generally is erratic in pattern and is high-energy in comparison to voice data. Any of a variety of algorithms may be used by the software to distinguish the voice data from the noise data. One such algorithm is the voice activity detector (VAD) algorithm described in U.S. Pat. No. 6,810,273, entitled “Noise Suppression,” and incorporated herein by reference.  
         [0026]     The background noise captured by microphone  102  is representative of the background noise of Person B&#39;s environment. If the intensity of this background noise is greater than the intensity of Person A&#39;s voice, Person A&#39;s voice will be inaudible to Person B. Accordingly, the DSP  200  compares the intensity of Person A&#39;s voice to that of the background noise of Person B&#39;s environment. If it is determined that the background noise is more intense than Person A&#39;s voice, the DSP  200  may use amplifier  218  to amplify one or more portions of Person A&#39;s voice such that it is audible over the background noise. The DSP  200  preferably amplifies only those portions of Person A&#39;s voice that are less intense than, or equal in intensity to, the background noise. However, in some embodiments, the DSP  200  may amplify an entire audio sample In other embodiments, the DSP  200  may amplify only a portion of an audio sample. In yet other embodiments, the DSP  200  may amplify multiple audio samples. The DSP&#39;s amplification protocol is determined by the signal processing software stored on memory  202  and may be adjusted by editing the software.  
         [0027]     After the appropriate portion(s) of Person A&#39;s voice data has been amplified, audio samples (i.e., both amplified and non-amplified audio samples) received from device  150  are forwarded to the speaker  104  in the order they are received by the device  100 . In this way, the DSP  200  reacts to increases in background noise by intensifying portions of Person A&#39;s voice that would otherwise be inaudible to Person B. Although not explicitly described herein, the DSP  200  may perform additional processing steps on signals received from the antenna  106  and/or the microphone  102 . For example, the DSP  200  may compress signals, decompress signals, transfer audio samples captured by microphone  102  to the antenna  106 , etc.  
         [0028]      FIG. 4  shows a flow diagram of a method  300  used to implement the techniques described above. The method  300  begins with receiving audio samples from microphone  102  and from device  100  via antenna  106  (block  302 ). The method  300  further comprises performing a spectral analysis on the audio samples to distinguish voice data from noise data (block  304 ). As previously mentioned, noise data typically is more erratic and has higher energy levels than voice data. Any suitable algorithm may be used to distinguish between voice and noise data, such as the VAD algorithm. The method  300  also comprises comparing the background noise captured by microphone  102  to the voice data received via antenna  106  (block  306 ). If it is determined that one or more portions of the voice data is less than or equal to the noise data in intensity (block  308 ), the method  300  comprises amplifying these one or more portions of the voice data (block  310 ). For example, the method  300  may comprise determining the difference in intensity between the noise and voice data and determining whether that intensity falls within some adjustable, predetermined range. Alternatively, the method  300  may comprise determining whether the difference in intensity falls below an adjustable, predetermined threshold.  
         [0029]     Amplifying a portion of voice data may include amplifying a portion of an audio sample, an entire audio sample, and/or a series of audio samples. In at least some embodiments, the method  300  comprises amplifying the voice data until it is more intense than the noise data. Furthermore, in some embodiments, the method  300  comprises amplifying the voice data until the difference in intensity between the noise and voice data falls outside the aforementioned predetermined range, or until the difference meets or exceeds the aforementioned threshold. The method  300  comprises transferring the audio samples (both amplified and non-amplified audio samples) to the speaker  104  (block  312 ) in the order they are received from the device  150 .  
         [0030]     Although the steps described in  FIG. 4  are shown in a preferred order, the steps may be performed in any suitable order. Moreover, although the method of  FIG. 4  is described in the context of device  100  (e.g., the embodiments of  FIG. 1 ), the method also may be adapted for implementation in device  150  (e.g., the embodiments of  FIG. 2 ). Further still, although the above embodiments describe the use of a single microphone  102  on device  100 , in some embodiments, multiple microphones may be used to capture audio data. Likewise, additional microphones may be used on device  150  in conjunction with microphone  152 .  
         [0031]     The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.