Abstract:
The present invention provides an electronic helmet for cancelling noises, which comprises a helmet including a plurality of microphones, a plurality of speakers and a first communication unit; and a mobile device including a second communication unit and a control unit. When the first communication unit in the helmet connects to the second communication unit in the mobile device, the control unit generates a plurality of control signals according to at least one sound or noise detected by the plurality of microphones. The mobile device uses the plurality of control signals to control the plurality of speakers outputting the at least one sound or anti-noise cancelling the noise. By the above electronic helmet, the present invention also provides a method integrating active noise control, hands-free communication, music listening, and voice navigation so as to achieve the proposes of cancelling the noises and improving the riding quality.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an electronic helmet, particularly relates to an electronic helmet and a method for noise cancellation. 
     BACKGROUND OF THE INVENTION 
     Convenience of daily life is improved along with science and technology progress. However, environment noise from transportation and industry causes damages on the sense of hearing. Presently, methods for noise cancellation are classified into passive noise control (PNC) and active noise control (ANC). Passive noise control is sound reduction by noise-isolating material such as sound-absorbing cotton. However, passive noise control neither truly eliminates noise nor totally overcomes low-frequency noise even using thick and weighty sound-absorbing cotton. Therefore, passive noise control neither resolves environment noise issue nor is convenient to be portable. Active noise control is a method for reducing unwanted sound by the addition of anti-noise. The anti-noise, whose phase is opposite to noise but amplitude is same as the ones of noise, is generated by a speaker according to a result of environment noise detection by a microphone. The environment noise cancellation can be achieved with the anti-noise to destroy strength of noise by forming destructive interference. 
     Presently, a helmet with active noise control combines an active noise control system into the helmet, which may provide a rider&#39;s head protection and environment noise cancellation. However, high cost results in little utilization frequency for such the helmet, except in aircraft industry, people working at aircraft stations protect themselves with such the helmets against noises from engines of aircraft. 
     US patent application of publication No. 20050117754 discloses a helmet of active noise cancellation, a vehicle system thereof and a method therefor. A rider may use an adaptive active noise control to cancel noise from wind, other vehicles and environment for improvement of riding quality. However, this helmet does not have noise cancellation combined with music preservation function and the peripheral circuit cost therefor is still too expensive. 
     Accordingly, the present invention provides an electronic helmet, and especially, an electronic helmet and cancellation method to integrate active noise control, hands-free communication, music listening, and voice navigation for noise cancellation. 
     SUMMARY OF THE INVENTION 
     One of objectives of the present invention provides an electronic helmet by using a mobile device as a platform of signal calculation/processing to replace a digital signal processor in a traditional active noise control. The mobile device may execute active noise control and generate control signals for controlling a speaker to output anti-noise that can cancel out the noise detected by a microphone. The noise cancellation, reduction of product cost and weight, readily portable convenience, and improvement of riding quality can be achieved. 
     Generally, it is necessary for a rider to wear a helmet when hitting a road. Wearing an earphone makes the helmet feel inconvenient, and making music out makes others feel bad. Accordingly, one of objectives of the present invention provides an electronic helmet of music-listening function that integrates a mobile device to execute a dual-channel and audio-integrating active noise control program and utilize a speaker to output sound of music and anti-noise. Thus, such an electronic helmet can cancel environment noise and preserve sound of music. 
     One of objectives of the present invention provides an electronic helmet of hands-free communication function for the rider&#39;s and others&#39; safeties when the rider would like to answer a call in riding. A mobile device executes an adaptive acoustic echo cancellation program and outputs the answer&#39;s voice and anti-noise with a speaker to cancel echo interference in communication and ensure answering important calls for the rider in using hands-free communication. 
     One of objectives of the present invention provides an electronic helmet of voice navigation function. Wireless positioning provides the rider a route and a direction in a voice way and ensures the rider safety when he or she checks transportation signs. 
     Accordingly, an electronic helmet of noise cancellation includes: an electronic helmet having a plurality of microphones, a plurality of speakers, and a first communication unit, wherein the microphones are respectively electrically coupled to the first communication unit and configured to at least detect an sound or a noise, and the speakers are respectively electrically coupled to the first communication unit and configured to at least output the sound or an anti-noise; and a mobile device having a second communication unit and a control unit, wherein the control unit is electrically coupled to the second communication unit; and wherein after the first communication unit of the electronic helmet are linked with the second communication unit of the mobile device, the control unit of the mobile device generates a plurality of control signals in the light of the sound or the noise detected by the microphones of the electronic helmet, and the speakers of the electronic helmet are controlled by the mobile device with the control signals to output the sound or the anti-noise that cancels out the noise. Thus, noise cancellation and riding quality improvement are achieved. 
     Accordingly, a method for noise cancellation includes: starting an electronic helmet and a control unit in a mobile device; coupling a first communication unit in the electronic helmet with a second communication unit in the mobile device; at least detecting an sound or a noise by a plurality of microphones in the electronic helmet; generating a plurality of control signals by the control unit in the mobile device in the light of the sound or the noise detected by the microphones of the electronic helmet; and at least outputting the sound or an anti-noise by a plurality of speakers that are controlled by the mobile device with the control signals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic system block diagram illustrating an electronic helmet for noise cancellation according to the present invention. 
         FIG. 2  is a schematic diagram illustrating the structure of an electronic helmet according to the present invention. 
         FIG. 3  is a schematic flow diagram illustrating one embodiment of active noise control according to the present invention. 
         FIG. 4  is a schematic flow diagram illustrating another embodiment of dual-channel active noise control program integrated with sound according to the present invention. 
         FIG. 5  is a schematic flow diagram illustrating one embodiment of adaptive acoustic echo cancellation program according to the present invention. 
         FIG. 6  is a schematic flow diagram illustrating a method for noise cancellation according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The above objects, technical features and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings. The presently described embodiments will be understood by reference to the drawings, but the sizes or ratios of components shown in drawings are not intended to limit the scope of the disclosure. 
       FIG. 1  is a schematic system block diagram illustrating an electronic helmet for noise cancellation according to the present invention. Shown in  FIG. 1 , an electronic helmet for noise cancellation includes an electronic helmet  10  having some microphones  101 , some speakers  102 , and a first communication unit  103 , and a mobile device  20  having a second communication unit  201 , and a control unit  202 . These microphones  101  are electrically coupled to the first communication unit  103  and configured to detect sound to be wanted (such as music) and noise not to be wanted (such as noise from vehicles). The speakers  102  are electrically coupled to the first communication unit  103  and configured to output sound or anti-noise. The control unit  202  is electrically coupled to the second communication unit  201 . After the second communication unit  201  of the mobile device  20  is coupled to the first communication unit  103  of the electronic helmet  10 , the control unit  202  generates multitudes of control signals in the light of at least the sound or noise detected by the microphones  101 . The speakers  102  are controlled by the control signals of the mobile device  20  to at least output the sound or the anti-noise for noise cancellation. Thus, noise can be cancelled and riding quality can be improved. 
     In a preferred embodiment of electronic helmet, the electronic helmet  10  further includes a power supply device of battery power to provide power to the microphones  101 , the speakers  102 , and the first communication unit  103 . 
     In a preferred embodiment of electronic helmet, the mobile device  20  may be a smart phone, a tablet computer or a mobile telecommunication, but not limited to. 
     In a preferred embodiment of electronic helmet, the first communication unit  103  and the second communication unit  201  may be one of a wired telecommunication module and a wireless telecommunication module. 
     In a preferred embodiment of electronic helmet, the wireless telecommunication module may be a blue tooth module. 
       FIG. 2  is a schematic diagram illustrating the structure of an electronic helmet according to the present invention. Shown in  FIG. 2 , the electronic helmet  10  includes three microphones  101   a ,  101   b  and  101   c , and two speakers  102   a  and  102   b . The speakers  102   a  and  102   b  are electrically coupled to the first communication unit  103  (not shown in  FIG. 2 ) and respectively deposited at two sides of the electronic helmet  10  to close to the position corresponding to user&#39;s ears, and configured to output the sound or the anti-noise. The three microphones  101   a ,  101   b  and  101   c  are electrically coupled to the first communication unit  103 . The three microphones  101   a ,  101   b , and  101   c  are deposited within the electronic helmet  10 . Both of the microphones  101   a  and  101   b  are deposited at the right and left inner sides of the electronic helmet  10  and below the two speakers  102   a  and  102   b , the microphone  101   c  is deposited around user&#39;s mouse position. The three microphones  101   a ,  101   b , and  101   c  are configured to at least detect the sound or the noise. When the user wears the electronic helmet  10  on the user&#39;s head, the electronic helmet  10  may create two quiet zones at the sides of the user&#39;s ears to cancel noise. It is noted that the numbers and arrangement of the microphones  101   a ,  101   b  and  101   c  and the speakers  102   a  and  102   b  in the electronic helmet  10  are only one embodiment for function and effect illustration of the electronic helmet  10 , not to be limited in the present invention or limit the scope of the present invention. 
     In electronic helmet of the present invention, the mobile device  20  further includes an active noise control program, a dual-channel audio-integrating active noise control program, and an adaptive acoustic echo cancellation program. A mobile phone application program is preferred ones for these programs aforementioned. Once user starts the mobile phone application program of the mobile device  20 , the second communication unit  201  in the mobile device  20  and the first communication unit  103  in the electronic helmet  10  are linked with each other, and the control unit  202  in the mobile device  20  executes the functions of the mobile phone application program. 
     The operation of the programs will be described as follows. 
       FIG. 3  is a schematic flow diagram illustrating one embodiment signal of active noise control program according to the present invention. Please refer to  FIG. 2  to  FIG. 3 , the active noise control program utilizes the three microphones  101   a ,  101   b  and  101   c  and the two speakers  102   a  and  102   b  deposited in the electronic helmet  10  as a signal input or output device. It is noted that S 1 (z) in  FIG. 3  is a secondary path frequency response from the speaker  102   a  to the microphone  101   a , S 2 (z) is the one from the speaker  102   b  to the microphone  101   b . Two estimated secondary path frequency responses Ŝ 1 (z), and Ŝ 2 (z), which are respectively corresponding to the secondary path frequency responses S 1 (z) and S 2 (z), are determined by selecting some suitable testing signals (such as white noises) to be outputted by the speakers  102   a  and  102   b  and detected by the microphones  101   a  and  101   b . Once the first communication unit  103  in the electronic helmet  10  and the second communication unit  201  in the mobile device  20  are linked, the electronic helmet  10  and the mobile device  20  start off receiving and transmitting signal. The three microphones  101   a ,  101   b  and  101   c  respectively detect the noises d 1 (n), d 2 (n) and x(n). Next, the control unit  202  of the mobile device  20  starts off executing the active noise control program after receiving the noises d 1 (n), d 2 (n) and x(n). Two adaptive wave filters W 1 (z) and W 2 (z) in program forms respectively generate two control signals y 1 (n) and y 2 (n) after receiving the noise x(n). Next, after the two control signals y 1 (n) and y 2 (n) are processed with the secondary path frequency responses S 1 (z) and S 2 (z) and outputted by the speakers  102   a  and  102   b , two anti-noises b 1 (n) and b 2 (n) are respectively generated and received by the microphones  101   a  and  101   b . Signal e 1 (n) may be generated by processing the anti-noises b 1 (n) and the noise d 1 (n) that is detected by the microphone  101   a  at same time. Meanwhile, signal e 2 (n) is generated by processing the anti-noises b 2 (n) and the noise d 2 (n) that is detected by the microphone  101   b . Next, both the two signals e 1 (n) and e 2 (n) together with the next noise x(n) may be inputted into a filtering algorithm A after they are processed with the secondary path frequency responses Ŝ 1 (z) and Ŝ 2 (z). The filtering algorithm A can adjust the two adaptive wave filters W 1 (z) and W 2 (z). The aforementioned process can be executed again after the next noises d 1 (n) and d 2 (n) are respectively detected by the two adjusted adaptive wave filters W 1 (z) and W 2 (z) together with the two microphones  101   a  and  101   b . In the embodiment, the filtering algorithm A may be Filtered-X Least Mean Square algorithm, but not limited to. The active noise control program of the embodiment is implemented by the control unit  202  of the mobile device  20  and generates the control signals y 1 (n) and y 2 (n) in the light of the noises d 1 (n), d 2 (n) and x(n) detected by the microphones  101   a ,  101   b  and  101   c  of the electronic helmet  10 . The two speakers  102   a  and  102   b  in the electronic helmet  10  output the anti-noises b 1 (n) and b 2 (n) to cancel noises d 1 (n), d 2 (n) and x(n). 
       FIG. 4  is a schematic flow diagram illustrating another embodiment of dual-channel and audio-integrating active noise control program according to the present invention. Please refer to  FIG. 2  and  FIG. 4 , the embodiment of dual-channel and audio-integrating active noise control program utilizes the three microphones  101   a ,  101   b  and  101   c  in the electronic helmet  10  and the two speakers  102   a  and  102   b  as signal input or output devices. It is noted that S 11 (z) in  FIG. 4  is a secondary path frequency response from the speaker  102   a  to the microphone  101   a , S 21 (z) is the one from the speaker  102   b  to the microphone  101   a , S 12 (z) is the one from the speaker  102   a  to the microphone  101   b , and S 22 (z) is the one from the speaker  102   b  to the microphones  101   b . Four estimated secondary path frequency responses Ŝ 11 (z), Ŝ 12 (z), Ŝ 21 (z) and Ŝ 22 (z) are determined by selecting a little suitable testing signals (such as white noise) to be outputted by the two speakers  102   a  and  102   b  and detected by the microphones  101   a  and  101   b . Once the first communication unit  103  in the electronic helmet  10  and the second communication unit  201  in the mobile device  20  are linked with each other, the electronic helmet  10  and the mobile device  20  start off receiving and transmitting signal. The dual-channel and audio-integrating active noise control program can start off executing after the three microphones  101   a ,  101   b  and  101   c  respectively detect the noises d 1 (n), d 2 (n) and x(n). The noise x(n) together with the signals e 1 (n) and e 2 (n) will be respectively inputted into the filtering algorithm A, after the noise x(n) is processed with the secondary path frequency responses Ŝ 11 (z) and Ŝ 22 (z). The filtering algorithm A1 can adjust the two wave filters W 1 (z) and W 2 (z) in the program forms. Two adaptive wave filters W 1 (z) and W 2 (z) in the program forms respectively generate two control signals u 1 (n) and u 2 (n) after receiving the noise x(n). The control signals y 1 (n) and y 2 (n), which are generated by combining the signals u 1 (n) and u 2 (n) and sound of music, control the speakers  102   a  and  102   b  to output the anti-noises a 11 (n) and a 22 (n) that are received by the microphones  101   a  and  101   b . Besides, the control signals y 1 (n) outputted by the speaker  102   a  may be transmitted to the microphone  101   b  (this frequency response shown as S 21 (z)) to generate sound a 21 (n). The control signals y 2 (n) outputted by the speaker  102   b  may be transmitted to the microphone  101   a  (this frequency response shown as S 12 (z)) to generate sound a 12 (n). Thus, signal q 1 (n) received by the microphone  101   a  includes the anti-noise a 11 (n), the sound a 12 (n) and the noise d 1 (n). In the meantime, signal q 2 (n) received by the microphone  101   b  includes the anti-noise a 22 (n), the sound a 21 (n) and the noise d 2 (n). After receiving the sound of music v(n), the estimated secondary path frequency responses Ŝ 11 (z), Ŝ 12 (z), Ŝ 21 (z) and Ŝ 22 (z) respectively output signals b 11 (n), b 12 (n), b 21 (n) and b 22 (n). Signal e 3 (n) will be generated by processing the signals q 1 (n) and b 11 (n). Similarly, signal e 4 (n) will be generated by processing the signals q 2 (n) and b 22 (n); signal e 2 (n) will be generated by processing the signals e 3 (n) and b 12 (n); and signal e 1 (n) will be generated by processing the signals e 4 (n) and b 21 (n). Next, the signals e 1 (n), e 2 (n), e 3 (n) and e 4 (n) are respectively inputted into inverter (K 1 , K 2 , K 3  and K 4 ), and then the inverter (K 1 , K 2 , K 3  and K 4 ) respectively output signals c 1 (n), c 2 (n), c 3 (n) and c 4 (n). Next, the signal c 1 (n) and the sound of music v(n) may be inputted into the filtering algorithm A 21 , the filtering algorithm A 21  will adjust the estimated frequency responses of secondary path Ŝ 21 (n). In the meantime, the signal c 2 (n) and the sound of music v(n) may be inputted into the filtering algorithm A 12 , the filtering algorithm A 12  will adjust the estimated frequency responses of secondary path Ŝ 12 (n); the signal c 3 (n) and the sound of music v(n) may be inputted into the filtering algorithm A 11 , the filtering algorithm A 11  will adjust the estimated frequency responses of secondary path Ŝ 11 (n); and the signal c 4 (n) and the sound of music v(n) may be inputted into the filtering algorithm A 22 , the filtering algorithm A 22  will adjust the estimated frequency responses of secondary path Ŝ 22 (n). The aforementioned process can be executed again after the next noises d 1 (n), d 2 (n) and x(n) are respectively detected by the four adjusted adaptive wave filters Ŝ 11 (n), Ŝ 12 (n), Ŝ 21 (n) and Ŝ 22 (n) together with the three microphones  101   a ,  101   b  and  101   c . In the embodiment, the filtering algorithm A 1  may be Filtered-X Least Mean Square algorithm, and the four filtering algorithms A 11 , A 12 , A 21  and A 22  may be Least Mean Square algorithm, but not limited to. The dual-channel and audio-integrating active noise control program of the embodiment is implemented by the control unit  202  in the mobile device  20  and generates the control signals y 1 (n), and y 2 (n) by combining the signals u 1 (n) and u 2 (n) with the sound of music v(n), in the light of the sound of music v(n) and the noises d 1 (n), d 2 (n) and x(n) detected by the microphones  101   a ,  101   b  and  101   c  of the electronic helmet  10 . The speakers  102   a  and  102   b  of the electronic helmet  10  are controlled by the mobile device  20  with the control signals y 1 (n) and y 2 (n), output the anti-noises a 11 (n) and a 22 (n) that may cancel the noises d 1 (n), d 2 (n) and x(n), and retain the sound of music v(n). 
       FIG. 5  is a schematic flow diagram illustrating one embodiment of adaptive acoustic echo cancellation program according to the present invention. Please refer to  FIG. 2  and  FIG. 5 , one microphone  101   c  in the electronic helmet  10  near user&#39;s mouse and the speaker  102   a  in the electronic helmet  10  near user&#39;s ear are utilized as signal input or output devices for the adaptive acoustic echo cancellation program. The sound v 1 (n) of an answer is outputted by the speaker  102   a , influenced by acoustic media and converted into the noise x(n) in echo form. The sound v 1 (n) is combined with user&#39;s sound v 2 (n) to generate signal q(n), and then the signal q(n) is detected by the microphone  101   c  near the user&#39;s mouse. Moreover, the sound v 1 (n) is inputted into the adaptive filter W 3 (z) in program form, and then the adaptive filter W 3 (z) can generate signal y(n). Next, the sound e(n) without echo interference is generated after signals q(n) and y(n) are processed, and then transferred into the answer&#39;s ear. The sound e(n) and the answer&#39;s sound v 1 (n) are inputted into a filtering algorithm A 3  for adjusting the adaptive filter W 3 (z). The aforementioned process can be executed again after the microphone  101   c  continuously detects user&#39;s next sound v 2 (n) and the noise x(n) that results from echo. In the embodiment, the filtering algorithm A3 may be a Least Mean Square algorithm, but not limited to. The adaptive acoustic echo cancellation program of the embodiment is implemented by the control unit  202  in the mobile device  20  and generates the control signal y(n) in the light of the sound v 2 (n) and the noise x(n) that are detected by the microphone  101   c  in the electronic helmet  10  and the voice signal v 1 (n) of a remote answer outputted by the speaker  102   a . Then the sound e(n) without echo interference can be generated and transmitted to the remote answer through the mobile device  20 . 
     Accordingly, the electronic helmet of the present invention includes the control unit  202  to have functions as follows: (1) the active noise control program used to cancel snore and noise; (2) the dual-channel and audio-integrating active noise control program used to cancel snore and noise but retain sound such as music; and (3) adaptive acoustic echo cancellation program used to cancel echo resulted from telecommunication. 
     Next, the electronic helmet of the present invention includes the control unit  202  to have voice navigation function. User speaks out a destination with his or her sound that is detected by the microphone  101   c  near the user&#39;s mouse. The control unit  202  of the mobile device  20  fixes the user&#39;s location and make a route plan to be outputted by the speakers  102   a  and  102   b  near the user&#39;s ears. 
     The method for noise cancellation is illustrated as follows. 
       FIG. 6  is a schematic flow diagram illustrating a method of snore and noise cancellation according to the present invention. Shown in  FIG. 6 , step  301 : user launches the electronic helmet  10  and the control unit  202  in the mobile device  20 , and the second communication unit  201  in the mobile device  20  may be automatically launched by the control unit  202 ; step  302 : the second communication unit  201  in the mobile device  20  is connected with the first communication unit  103  in the electronic helmet  10 ; step  303 : multitudes of the microphones  101  in the electronic helmet  10  at least detect the sound or the noise; step  304 : the control unit  202  in the mobile device  20  generates multitudes of control signals in the light of at least the sound or the noise detected by the microphones  101  in the electronic helmet  10 ; and step  305 : with the control signals, the mobile device  20  controls multitudes of the speakers  102  in the electronic helmet  10  to at least output the sound or anti-noise. 
     Accordingly, an electronic helmet of snore and noise cancellation is provided, which includes: the electronic helmet  10  having multitudes of the microphones  101 , multitudes of the speakers  102  and the first communication unit  103 ; and the mobile device  20  having the second communication unit  201  and the control unit  202 . If the first communication unit  103  of the electronic helmet  10  and the second communication unit  201  of the mobile device  20  are connected, the control unit  202  generates multitudes of control signals in the light of the sound or noise detected by the microphones  101 , and the mobile device  20  controls the speakers  102  with the control signal to output the sound or/and anti-noise that may cancel out the noise. With the electronic helmet, a method of integrating active noise control, hand-free communication, music listening, and voice navigation is also provided for the purposes for noise cancellation and improvement on riding quality. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.