Communicating road noise control system, in-vehicle road noise controller, and server

Road noise is reduced without locally storing noise spectrum patterns for determination or without detecting the present position of a vehicle from the device. An in-vehicle hands-free device causes a cellular phone to detect the present position of the vehicle and transmit the position to a server. The server determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running. The noise spectrum pattern is based on the present position of the vehicle received from the in-vehicle hands-free device and road information. The server transmits the noise spectrum pattern to the in-vehicle hands-free device whereupon a noise canceling signal is superimposed on a received signal. The noise canceling signal is based on an inverted noise spectrum pattern that is obtained by inverting the phase of the noise spectrum pattern. The resulting composite signal is output from a speaker.

CROSS REFERENCE TO RELATED APPLICATIONS

The present invention is based on and claims priority to Unpublished Japanese Patent Application No. 2007-027959 filed on Feb. 7, 2007 and Unpublished Japanese Patent Application No. 2007-305898 filed on Nov. 27, 2007, the contents of both of which are incorporated in their entirety herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to a road noise control system, and more specifically to an in-vehicle road noise controller and a server communicating through a communication network.

2. Description of Related Art

Various technologies have been developed to facilitate an environment for a hands-free telephone conversation carried out in a vehicle compartment. One technology involves determining a noise spectrum pattern corresponding to the road surface on which a vehicle is presently running based on the present position of the vehicle and road information. The determined noise spectrum pattern is selected from among multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces and is outputted. Road noise is reduced based on the outputted noise spectrum pattern as described, for example, in JP-A-2003-344083.

However, the apparatus described in JP-A-2003-344083 detects the present position of the vehicle. Therefore, the noise control in the apparatus cannot be implemented independently, that is, without detecting the present position of the vehicle. The apparatus stores multiple different noise spectrum patterns corresponding to multiple different road surfaces, and determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running from among the different noise spectrum patterns. Therefore, a very large memory is required to store noise spectrum patterns. Further, the amount of storable noise spectrum patterns is thereby limited to the available storage space and the size of the noise spectrum patterns.

The invention has been made in consideration of the foregoing. Therefore, it is an object of the invention to provide a communicating road noise control system, an in-vehicle road noise controller, and a server wherein road noise can be appropriately reduced even when a function of detecting the present position of a vehicle or a function of storing noise spectrum patterns for determination is not provided.

According to a first aspect, the communicating road noise control system is provided with an in-vehicle road noise controller. A present position detection and transmission instructing means causes an external device to detect the present position of the vehicle and transmit the present position to the server. In the server, a present position receiving means receives the present position from the external device. A noise spectrum pattern determining means (hereinafter “determining means”) determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running based on the received present position of the vehicle and road information stored in a map data storing means. A noise spectrum pattern outputting means selects the noise spectrum pattern determined by the determining means from among multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces and outputs the selected pattern. A noise spectrum pattern transmitting means transmits the outputted noise spectrum pattern to the in-vehicle road noise controller. In the in-vehicle road noise controller, a noise spectrum pattern receiving means receives the noise spectrum pattern from the server. A road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, the present position of the vehicle is detected by the external device, not by the in-vehicle road noise controller. The multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server, not in the in-vehicle road noise controller. Further, of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server, not by the in-vehicle road noise controller. Thus, road noise can be appropriately reduced even in an in-vehicle controller that does not detect the present position of the vehicle or that does not store noise spectrum patterns for determination. Since the multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server, a large storage capacity can be ensured for noise spectrum patterns. Further, updated noise spectrum patterns can be provided to the server, for example, from external sources, independently of the operation of the in-vehicle controller.

In accordance with a second aspect of the in-vehicle road noise controller, a present position detection and transmission instructing means causes an external device to detect the present position of the vehicle and causes the external device to transmit it to the server. When a noise spectrum pattern receiving means receives a noise spectrum pattern from the server, a road noise reducing means reduces road noise based on the received noise spectrum pattern.

When the in-vehicle road noise controller is used in the communicating road noise control system together with the server described in accordance with a sixth aspect, the same action and effect as described in the first aspect can be obtained. That is, road noise can be appropriately reduced even with an in-vehicle controller construction that does not have a function of detecting the present position of the vehicle or a function of storing noise spectrum patterns for determination.

According a third aspect of the communicating road noise control system, in the in-vehicle road noise controller, a present position detecting means detects the present position of the vehicle. A present position transmitting means transmits the detected present position of the vehicle to the server. In the server, a present position receiving means receives the present position of the vehicle from the in-vehicle road noise controller. The determining means then determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running based on the received present position of the vehicle and road information stored in a map data storing means. A noise spectrum pattern outputting means selects the noise spectrum pattern determined by the determining means from among the multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces and outputs the selected pattern. A noise spectrum pattern transmitting means transmits the outputted noise spectrum pattern to the in-vehicle road noise controller. In the in-vehicle road noise controller, a noise spectrum pattern receiving means receives the noise spectrum pattern from the server. Then, a road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, the multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server, not in the in-vehicle road noise controller. Further, of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server, not by the in-vehicle road noise controller. Thus, road noise can be appropriately reduced even with a construction that does not have a function of storing noise spectrum patterns for determination.

According to the in-vehicle road noise controller described in a fourth aspect, a present position detecting means detects the present position of the vehicle. A present position transmitting means transmits the detected present position of the vehicle to the server. A noise spectrum pattern receiving means receives a noise spectrum pattern from the server. Then, a road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, when the in-vehicle road noise controller is used in the communicating road noise control system together with the server described in a seventh aspect, the same action and effect as described in the third aspect can be obtained. That is, road noise can be appropriately reduced even with a construction that does not have a function of storing noise spectrum patterns for determination.

According to the in-vehicle road noise controller described in a fifth aspect, a present position acquiring means acquires the present position of the vehicle from an external device. A noise spectrum pattern determining means (hereinafter “determining means”) determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running based on the acquired present position of the vehicle and road information stored in a map data storing means. A noise spectrum pattern outputting means selects the noise spectrum pattern determined by the determining means from among the multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces and outputs the selected pattern. A road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, the present position of the vehicle is acquired from the external device, not detected by the in-vehicle road noise controller. Therefore, road noise can be appropriately reduced even with a construction that does not have a function of detecting the present position of the vehicle.

According to the communicating road noise control system described in an eight aspect, in the in-vehicle road noise controller, a present position detection and transmission instructing means causes an external device to detect the present position of the vehicle and causes the external device to transmit it to the server. A noise spectrum pattern transmitting means transmits a noise spectrum pattern to the server. In the server, a present position receiving means receives the present position of the vehicle from the external device. A noise spectrum pattern receiving means receives a noise spectrum pattern from the in-vehicle road noise controller. Then, a noise spectrum pattern optimizing means analyzes the received noise spectrum pattern to cancel a non-stationary component with a stationary component left and thereby optimizes the noise spectrum pattern. A noise spectrum pattern determining means determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running. The above noted determination is carried out based on the present position of the vehicle received by the present position receiving means and road information stored in a map data storing means. A noise spectrum pattern outputting means stores multiple different noise spectrum patterns optimized by the noise spectrum pattern optimizing means in correspondence with multiple different road surfaces. Further, it selects the noise spectrum pattern determined by the determining means from among the multiple different noise spectrum patterns and outputs the selected pattern. A noise spectrum pattern transmitting means transmits the outputted noise spectrum pattern to the in-vehicle road noise controller. In the in-vehicle road noise controller, a noise spectrum pattern receiving means receives the noise spectrum pattern from the server. Then, a road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, the same action and effect as described in the first aspect can be obtained. The present position of the vehicle is detected by the external device, not by the in-vehicle road noise controller. The multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server, not in the in-vehicle road noise controller. Further, of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server, not by the in-vehicle road noise controller. Thus, road noise can be appropriately reduced even with a construction that does not have a function of detecting the present position of the vehicle or a function of storing noise spectrum patterns for determination. Since the multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server, a large storage capacity can be ensured for noise spectrum patterns. Since a noise spectrum pattern with a stationary component left and a non-stationary component canceled is transmitted to the in-vehicle road noise controller, it is possible to more appropriately reduce road noise and thus enhance accuracy.

According to the in-vehicle road noise controller described in a ninth aspect, a present position detection and transmission instructing means causes an external device to detect the present position of the vehicle and causes the external device to transmit it to the server. A noise spectrum pattern transmitting means transmits a noise spectrum pattern to the server. A noise spectrum pattern receiving means receives a noise spectrum pattern from the server. Then, a road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, when the in-vehicle road noise controller is used in the communicating road noise control system together with the server described in a twelfth aspect, the same action and effect as described in the first aspect can be obtained. That is, road noise can be appropriately reduced even with a construction that does not have a function of detecting the present position of the vehicle or a function of storing noise spectrum patterns for determination. Since a noise spectrum pattern with a stationary component left and a non-stationary component canceled is transmitted to the in-vehicle road noise controller, it is possible to more appropriately reduce road noise and thus enhance accuracy.

According to the communicating road noise control system described in a tenth aspect, in the in-vehicle road noise controller, a present position detecting means detects the present position of the vehicle. A present position transmitting means transmits the detected present position of the vehicle to the server. A noise spectrum pattern transmitting means transmits a noise spectrum pattern to the server. In the server, a present position receiving means receives the present position of the vehicle from the in-vehicle road noise controller and a noise spectrum pattern receiving means receives a noise spectrum pattern from the in-vehicle road noise controller. Then, a noise spectrum pattern optimizing means analyzes the received noise spectrum pattern to cancel a non-stationary component with a stationary component left and thereby optimizes the noise spectrum pattern. A noise spectrum pattern determining means (hereinafter “determining means”) determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running. The above described determination is carried out based on the present position of the vehicle received by the present position receiving means and road information stored in a map data storing means. A noise spectrum pattern outputting means stores multiple different noise spectrum patterns optimized by the noise spectrum pattern optimizing means in correspondence with multiple different road surfaces. Further, it selects the noise spectrum pattern determined by the determining means from among the multiple different noise spectrum patterns and outputs the selected pattern. A noise spectrum pattern transmitting means transmits the outputted noise spectrum pattern to the in-vehicle road noise controller. In the in-vehicle road noise controller, a noise spectrum pattern receiving means receives the noise spectrum pattern from the server. Then, a road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, the same action and effect as described in the third aspect can be obtained. The multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server, not in the in-vehicle road noise controller. Further, of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server, not by the in-vehicle road noise controller. Thus, road noise can be appropriately reduced even with a construction that does not have a function of storing noise spectrum patterns for determination. Since a noise spectrum pattern with a stationary component left and a non-stationary component canceled is transmitted to the in-vehicle road noise controller, it is possible to more appropriately reduce road noise and thus enhance accuracy.

According to the in-vehicle road noise controller described in an eleventh aspect, a present position detecting means detects the present position of the vehicle. A present position transmitting means transmits the detected present position of the vehicle to the server. A noise spectrum pattern transmitting means transmits a noise spectrum pattern to the server. A noise spectrum pattern receiving means receives a noise spectrum pattern from the server. Then, a road noise reducing means reduces road noise based on the received noise spectrum pattern.

Thus, when the in-vehicle road noise controller is used in the communicating road noise control system together with the server described in a thirteenth aspect, the same action and effect as described in the third aspect can be obtained. That is, road noise can be appropriately reduced even with a construction that does not have a function of storing noise spectrum patterns for determination. Since a noise spectrum pattern with a stationary component left and a non-stationary component canceled is transmitted to the in-vehicle road noise controller, it is possible to more appropriately reduce road noise and thus enhance accuracy.

According to the communicating road noise control system described in a fourteenth aspect, in the in-vehicle road noise controller, an additional information acquiring means acquires additional information that can have influence on noise spectrum patterns. A noise spectrum pattern transmitting means transmits a noise spectrum pattern affixed with the additional information acquired by the additional information acquiring means to the server. Thus, a noise spectrum pattern affixed with additional information that can have influence on noise spectrum patterns is transmitted to the server and the server considers the additional information received from the in-vehicle road noise controller. Thus, it is possible to select the noise spectrum pattern most suitable for reducing road noise and thus enhance accuracy.

According to the in-vehicle road noise controller described in a fifteenth aspect, an additional information acquiring means acquires additional information that can have influence on noise spectrum patterns. A noise spectrum pattern transmitting means transmits a noise spectrum pattern affixed with the additional information acquired by the additional information acquiring means to the server. Thus, a noise spectrum pattern affixed with additional information that can have influence on noise spectrum patterns is transmitted to the server and the server considers the additional information received from the in-vehicle road noise controller. Thus, it is possible to select the noise spectrum pattern most suitable for reducing road noise and thereby enhance accuracy.

According to the in-vehicle road noise controller described in a nineteenth aspect or a twenty-third aspect, a noise canceling means superimposes a noise canceling signal on a transmit signal to cancel a road noise component from the transmit signal. The above described noise canceling signal is based on an inverted noise spectrum pattern obtained by inverting the phase of a noise spectrum pattern received by a noise spectrum pattern receiving means. Therefore, a high-quality transmit signal with a road noise component canceled can be transmitted to the other party of telephone conversation.

According to the in-vehicle road noise controller described in a twenty-seventh aspect, a noise canceling means superimposes a noise canceling signal on a transmit signal to cancel a road noise component from the transmit signal. The above described noise canceling signal is based on an inverted noise spectrum pattern obtained by inverting the phase of a noise spectrum pattern outputted by a noise spectrum pattern outputting means. Therefore, a high-quality transmit signal with a road noise component canceled can be transmitted to the other party of telephone conversation.

According to the in-vehicle road noise controller described in a twenty-eighth aspect, a phonetic recognition means phonetically recognizes a transmit signal with a road noise component canceled by a noise canceling means. Therefore, it is possible to phonetically recognize a high-quality transmit signal and enhance a phonetic recognition rate.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

First Embodiment

Hereafter, description will be given to a first embodiment of the invention with reference toFIG. 1andFIG. 2.FIG. 1illustrates the overall configuration of a communicating road noise control system in the form of functional block diagram. In accordance with the communicating road noise control system1, an in-vehicle hands-free device2and a cellular phone3can communicate with each other via, for example, a Bluetooth® or similar short range or proximity-based protocol; and the cellular phone3and the server4can communicate with each other in a wide area via a wide area network. It should be noted that the in-vehicle hands-free device can refer to and include the in-vehicle road noise controller and the cellular phone can refer to telephone means and external device in accordance with the invention as described herein.

The in-vehicle hands-free device2can include a control unit5for carrying out for example, present position detection and acting as the transmission instructing means as described herein, a Bluetooth® communication unit6, which can act as the noise spectrum pattern receiving means as described herein, a microphone7, which can act as the voice inputting means as described herein, and a speaker8, which can act as the voice outputting means as described herein. The control unit5includes a microcomputer, such as a general, purpose computer, special purpose computer, application specific integrated circuit (ASIC), logic array, processor, controller, or the like, which has CPU, ROM, RAM, I/O, interconnected with a bus line. The microphone7is placed in proximity to the driver in the vehicle compartment, and is disposed in, for example, the headrest of the seat, the steering wheel, the sun visor, or the like. The speaker8is disposed in, for example, the instrument panel in the vehicle compartment, the ceiling of the vehicle interior, the front seat door, or the like.

The control unit5includes a first A-D conversion unit9and a first D-A conversion unit10in a transmitter system and a second A-D conversion unit11and a second D-A conversion unit12in a receiver system. In the present embodiment, the first A-D conversion unit9, first D-A conversion unit10, second A-D conversion unit11, and second D-A conversion unit12construct a voice relaying means13. Further, the control unit5includes an active noise control unit14, which can act as the road noise reducing means and active noise controlling means as described herein, a noise cancellation unit15, which can act as the noise canceling means as described herein, an echo cancellation unit16; and a phonetic recognition unit17, which can act as the phonetic recognition means as described herein. It will be appreciated that by voice signal herein, for example in the context of the microphone7, reference can be made to a voice frequency signal that may contain a voice signal and may also contain other components within the frequency range of the microphone such as road noise or other noise falling within the voice frequency spectrum of the microphone.

The active noise control unit14includes a noise spectrum pattern phase inversion unit18(hereinafter “phase inversion unit18”) and a third D-A conversion unit19. When the phase inversion unit18receives a noise spectrum pattern from the server4by the Bluetooth® communication unit6via the cellular phone3, the phase of the received noise spectrum pattern is advanced or delayed by 180 degrees. An inverted noise spectrum pattern is thereby generated by inverting the phase of the noise spectrum pattern and outputting the inverted pattern to the third D-A conversion unit19. When an inverted noise spectrum pattern is inputted from the phase inversion unit18, the third D-A conversion unit19converts the inputted inverted noise spectrum pattern from digital signal to analog signal to generate a noise canceling signal. The generated noise canceling signal is output to the speaker8. That is, the active noise control unit14superimposes on the received voice signal, a noise canceling signal having a phase opposite that of a road noise component present in the vehicle compartment. The active noise control unit outputs the composite signal, that is, the noise canceling signal plus road noise, to the speaker8to produce the active noise control effect.

The noise cancellation unit15includes a noise spectrum pattern phase inversion unit20(hereinafter “phase inversion unit20”) and a first adder21. The phase inversion unit20operates similarly with the above-mentioned phase inversion unit18in that, when a noise spectrum pattern is received from the server4by the Bluetooth® communication unit6via the cellular phone3, the phase inversion unit20advances or delays the phase of the received noise spectrum pattern by 180 degrees thereby generating an inverted noise spectrum pattern. The inverted pattern is then output to the first adder21. That is, the noise cancellation unit15superimposes on the transmit signal, a noise canceling signal having a phase opposite that of a road noise component present in the vehicle compartment. The noise cancellation unit thereby cancels the road noise component inputted from the microphone7.

The echo cancellation unit16includes an echo filter22and a second adder23, and cancels an acoustic echo component inputted from the microphone7. The phonetic recognition unit17phonetically recognizes a transmit signal with a road noise component canceled by the noise cancellation unit15and an acoustic echo component canceled by the echo cancellation unit16.

The cellular phone3includes a control unit24, a Bluetooth® communication unit25, an operating unit26, a display unit27, a telephone communication unit28, a microphone29, a speaker30, and a position detection unit31. The position detection unit31includes, for example, a global positioning system (GPS) receiver that computes GPS signals to detect the present position. By operation of the control unit24, when a present position detection and transmission request is inputted from the in-vehicle hands-free device2, the position detection unit31detects the present position and the telephone communication unit28transmits the detected present position as the present position of the vehicle to the server4. When a noise spectrum pattern is received by the control unit24from the server4by the telephone communication unit28, the Bluetooth® communication unit25is directed to transmit the received noise spectrum pattern to the in-vehicle hands-free device2.

The server4includes a noise spectrum pattern unit32, a telephone communication unit33, which can act as for example, a present position receiving means and noise spectrum pattern transmitting means in accordance with the invention, and a map data storage unit34map data storing means in the invention. The noise spectrum pattern unit32includes a noise spectrum pattern determination unit35, which can act as noise spectrum pattern determining means in accordance with the invention and a noise spectrum pattern output unit36, which can act as noise spectrum pattern outputting means in accordance with the invention.

The map data storage unit34stores road information. When the noise spectrum pattern determination unit35receives the present position of the vehicle from the cellular phone3by the telephone communication unit33, a noise spectrum corresponding to the road surface on which the vehicle is presently running is determined. The above described determination is carried out based on the received present position of the vehicle and road information stored in the map data storage unit34. The noise spectrum pattern output unit36stores multiple different noise spectrum patterns in correspondence with multiple different road surfaces. It selects the noise spectrum pattern determined by the noise spectrum pattern determination unit35from among the multiple different noise spectrum patterns and outputs the selected pattern to the telephone communication unit33. When the noise spectrum pattern is inputted from the noise spectrum pattern output unit36, the telephone communication unit33transmits the inputted noise spectrum pattern to the cellular phone3.

Description will be given to the action of the above construction with reference toFIG. 2. When the user starts phonetic recognition or a hands-free telephone call, for example, the in-vehicle hands-free device2receives a noise spectrum pattern from the server4via the cellular phone3and generates a noise canceling signal as will be described in detail herein after.

The in-vehicle hands-free device2transmits a present position detection and transmission request to the cellular phone3. When the cellular phone3receives the present position detection and transmission request from the in-vehicle hands-free device2, the present position of the vehicle is detected at S1. Then, the detected present position of the vehicle is transmitted to the server4.

When the server4receives the present position of the vehicle from the cellular phone3, a noise spectrum corresponding to the road surface on which the vehicle is presently running is determined at S2. The above described determination is carried out based on the received present position of the vehicle and road information stored in the map data storage unit34. The server then selects the determined noise spectrum pattern from among multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces and outputs the selected pattern at S3. The outputted noise spectrum pattern is then transmitted to the cellular phone3.

When the cellular phone3receives the noise spectrum pattern from the server4, the received noise spectrum pattern is transmitted to the in-vehicle hands-free device2whereupon the received noise spectrum pattern is input to the active noise control unit14and the noise cancellation unit15. The in-vehicle hands-free device2inverts the phase of the noise spectrum pattern at the active noise control unit14and the noise cancellation unit15to generate the above mentioned inverted noise spectrum pattern at S4. The in-vehicle hands-free device generates a noise canceling signal based on the generated inverted noise spectrum pattern at S5.

When a transmitted voice signal, a road noise component, and an acoustic echo component are inputted as a transmit signal from the microphone7, the following operations can take place in the in-vehicle hands-free device2. The control unit5converts the inputted transmit signal from analog signal to digital signal at the first A-D conversion unit9, and superimposes a noise canceling signal generated by the noise cancellation unit15on the transmit signal in order to cancel the road noise component. The control unit5then cancels the acoustic echo component at the echo cancellation unit16, and converts the digital signal into an analog signal at the first D-A conversion unit10. The control unit5then causes the Bluetooth® communication unit6to transmit a transmit signal approximated to the transmitted voice to the other party of telephone conversation via the cellular phone3.

When the control unit5receives a signal from the other party of telephone conversation by the Bluetooth® communication unit6via the cellular phone3, the received signal is converted from analog signal to digital signal at the second A-D conversion unit11, converts the digital signal into an analog signal at the second D-A conversion unit12, and outputs the analog signal as a received voice signal to the speaker8. In the above described case, the control unit5superimposes a noise canceling signal generated by the active noise control unit14on the received voice and outputs the composite signal to the speaker8.

Thus, with respect to received voice, a noise canceling signal generated by the active noise control unit14is superimposed on the received voice and it is outputted to the speaker8. Thus, a road noise component present in the vehicle compartment can be canceled. With respect to a transmitted voice signal, a noise canceling signal generated by the noise cancellation unit15is superimposed on the transmit signal. Thus, a road noise component input into the microphone7can be canceled making it possible to produce the active noise control effect and stabilize hands-free telephone conversation.

When there are multiple types of road surfaces between the present position of the vehicle and a destination, multiple noise spectrum patterns corresponding to the multiple types of road surfaces are transmitted beforehand from the server4to the in-vehicle hands-free device2, and stored in the in-vehicle hands-free device2. Thus, when the road surface on which the vehicle runs changes, a noise canceling signal can be outputted without delay, and the active noise control effect can be produced without interruption. As a result, hands-free telephone conversation can be continuously stabilized.

Further, the noise spectrum pattern determination unit35is adapted to the vehicle speed detected by a vehicle speed sensor (not shown). Multiple noise spectrum patterns are stored in the noise spectrum pattern output unit36in correspondence with multiple different vehicle speeds making it possible to simultaneously cancel such a noise component as wind noise produced because the vehicle speed differs even though the vehicle is running on road surfaces of a kind. More specific description will be given. When a vehicle running on an asphalt-paved open road enters an asphalt-paved highway, for example, the vehicle speed is significantly increased. The above construction makes it possible to cancel a noise component, such as wind noise, produced in such a vehicle and to further stabilize hands-free telephone conversation.

The method for road noise reduction described above is such that a noise spectrum pattern is actively controlled by the active noise control unit14to reduce road noise. Instead, road noise may be reduced by subjecting a noise spectrum pattern to spectrum subtraction or using an acoustic model for a noise spectrum pattern.

According to the first embodiment, the in-vehicle hands-free device2causes the cellular phone3to detect the present position of the vehicle and causes the cellular phone3to transmit it to the server4. The server4determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running. The above described determination is carried out based on the present position of the vehicle received from the cellular phone3and road information stored in the map data storage unit34. The server selects the determined noise spectrum pattern from among multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces, and transmits the selected pattern to the in-vehicle hands-free device2via the cellular phone3. The in-vehicle hands-free device2superimposes a noise canceling signal on the received voice and outputs the composite signal to the speaker8. The above described noise canceling signal is based on an inverted noise spectrum pattern obtained by inverting the phase of the noise spectrum pattern received from the server4via the cellular phone3.

Thus, the present position of the vehicle is detected by the cellular phone3, not by the in-vehicle hands-free device2. The multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server4, not in the in-vehicle hands-free device2. Of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server4, not by the in-vehicle hands-free device2. Thus, the present position of the vehicle or a function of storing noise spectrum patterns for determination for achieving the active noise control effect can be determined and achieved and road noise can be appropriately reduced in an in-vehicle device independent of detecting the position.

Since the multiple different noise spectrum patterns are stored in the server4in correspondence with multiple different road surfaces, a large storage capacity can be ensured for noise spectrum patterns. Since a noise canceling signal is superimposed on a transmit signal to cancel a road noise component from the transmit signal, a high-quality transmit signal with a road noise component canceled can be transmitted to the other party of telephone conversation. Further, since a transmit signal with a road noise component canceled is phonetically recognized, a high-quality transmit signal can be phonetically recognized and thus a phonetic recognition rate can be enhanced.

Second Embodiment

Description will now be given to a second embodiment of the invention with reference toFIG. 3. It should be noted that description of the same members as in the first embodiment will be omitted for simplicity, and the description will be focused on the differences.

As described herein above, in accordance with the first embodiment, the present position of the vehicle is detected by the cellular phone3, multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server4, and of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server4. Meanwhile, in accordance with the second embodiment, the in-vehicle hands-free device detects the present position of the vehicle and transmits it to the server4.

In a communicating road noise control system41, an in-vehicle hands-free device42and a cellular phone43can communicate with each other via, for example, a Bluetooth® protocol or other short range or proximity-based protocol, and the cellular phone43and the server4can communicate with each other in a wide area via a wide area network. The in-vehicle hands-free device42includes a position detection unit45having the same functions as those of the position detection unit31of the cellular phone3described in relation to the first embodiment. It should be noted that the position detection unit45can correspond to the present position detecting means in accordance with the invention. A control unit44outputs a present position detection request to the position detection unit45causing the position detection unit45to detect the present position of the vehicle. The control unit44causes a Bluetooth® communication unit46, which can act as the present position transmitting means in accordance with the invention, to transmit the detected present position of the vehicle to the cellular phone43and causes the cellular phone43to transmit the present position of the vehicle to the server4.

When the server4receives the present position of the vehicle detected by the in-vehicle hands-free device42from the cellular phone43, the server4can perform the same operation as described in relation to a first embodiment. That is, the server determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running. The determination is carried out based on the received present position of the vehicle and road information stored in the map data storage unit34. The server4selects the determined noise spectrum pattern from among the multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces and transmits the selected pattern to the cellular phone43. Then, the server4causes the cellular phone43to transmit the selected pattern to the in-vehicle hands-free device42.

According to the second embodiment, the in-vehicle hands-free device42detects the present position of the vehicle and causes the cellular phone43to transmit the detected position to the server4. The server4determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running. The above described determination is carried out based on the present position of the vehicle received from the cellular phone43and road information stored in the map data storage unit34. The server4selects the determined noise spectrum pattern from among the multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces, and transmits the selected pattern to the in-vehicle hands-free device42via the cellular phone43. The in-vehicle hands-free device42superimposes a noise canceling signal on the received voice signal and outputs the composite signal to the speaker8. The noise canceling signal is based on an inverted noise spectrum pattern obtained by inverting the phase of the noise spectrum pattern received from the server4via the cellular phone43.

Thus, the multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server4, not in the in-vehicle hands-free device42. Further, of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server4, not by the in-vehicle hands-free device42. Thus, the active noise control effect can be appropriately produced and road noise can be appropriately reduced even when noise spectrum patterns for determination are not locally stored.

Third Embodiment

Description will now be given to a third embodiment of the invention with reference toFIG. 4. The description of the same members as in the first embodiment will be omitted, and description will be focused on the differences. In accordance with a third embodiment, the in-vehicle hands-free device acquires the present position of the vehicle from the cellular phone and determines a noise spectrum pattern.

In a communicating road noise control system51, an in-vehicle hands-free device52and the cellular phone3can communicate with each other via, for example, a Bluetooth® protocol or other short range or proximity-based protocol. The in-vehicle hands-free device52includes a noise spectrum pattern unit54, a noise spectrum pattern determination unit55, a noise spectrum pattern output unit56, and a map data storage unit57having the same functions as those of the noise spectrum pattern unit32, noise spectrum pattern determination unit35, noise spectrum pattern output unit36, and map data storage unit34of the server4described in relation to a first embodiment. A control unit53, which can act as present position acquiring means in accordance with the invention, outputs a present position detection request from the Bluetooth® communication unit46to the cellular phone3, causes the position detection unit31of the cellular phone3to detect the present position of the vehicle, receives the detected present position of the vehicle by the Bluetooth® communication unit46, and thereby acquires the present position of the vehicle from the cellular phone3.

After acquiring the present position of the vehicle from the cellular phone3, the control unit53determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running based on the acquired present position of the vehicle and road information stored in the map data storage unit57. The control unit53selects the determined noise spectrum pattern from among the multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces and outputs the selected pattern.

According to a third embodiment, the in-vehicle hands-free device52acquires the present position of the vehicle from the cellular phone3and determines a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running based on the acquired present position of the vehicle and road information stored in the map data storage unit57. The in-vehicle hands-free device superimposes a noise canceling signal on received voice and outputs the composite signal to the speaker8. The above described noise canceling signal is based on an inverted noise spectrum pattern obtained by inverting the phase of the determined noise spectrum pattern among the multiple different noise spectrum patterns stored in correspondence with multiple different road surfaces.

Thus, the present position of the vehicle is detected by the cellular phone3, not by the in-vehicle hands-free device52. As a result, it is possible, even with a construction that does not detect the present position of the vehicle, to appropriately produce the active noise control effect and appropriately reduce road noise by taking the same measure as described in the first aspect.

Fourth Embodiment

Description will be given to a fourth embodiment of the invention with reference toFIG. 5toFIG. 7. The description of the same members as in the telephone communication unit65. A non-stationary component can be canceled leaving a stationary component and thereby optimizing the noise spectrum pattern as will be described in greater detail. The noise spectrum pattern unit66analyzes, for example, by gathering statistic about multiple noise spectrum patterns received from the in-vehicle hands-free device62at a common point by the telephone communication unit65. A stationary component, such as road noise, is left and non-stationary components, such as conversation sound from occupants, operating noise from wiper or air conditioner, engine sound and exhaust sound from other vehicles, are canceled thereby optimizing the noise spectrum pattern. It should be noted that during the analysis, the averages of the noise spectrum patterns are taken. The noise spectrum pattern unit66receives various information from various servers, such as a weather information delivery server for delivering weather information, a traffic information delivery server for delivering traffic information, and the like, via a communication network.

Description will now be given to the action of the above-mentioned construction with reference toFIG. 6andFIG. 7. It will be assumed that the server63receives weather information transmitted from a weather information delivery server.

In the above described case, the server63optimizes a noise spectrum pattern as described below. The in-vehicle hands-free device62transmits a present position detection and transmission request to the cellular phone3, and then computes a noise spectrum pattern at S11. Whereupon the computed noise spectrum pattern is transmitted to the cellular phone3. When the cellular phone3receives the present position detection and transmission request from the in-vehicle hands-free device2, the present position of the first embodiment will be omitted for simplicity, and description will be focused on the differences. In accordance with the first to third embodiments, the in-vehicle hands-free device does not transmit a noise spectrum pattern to the server. Meanwhile, in accordance with the fourth embodiment, the in-vehicle hands-free device does transmit a noise spectrum pattern to the server.

In a communicating road noise control system61, an in-vehicle hands-free device62and the cellular phone3can communicate with each other and the cellular phone3and a server63can communicate with each other in a wide area via a wide area network. In the in-vehicle hands-free device62, a Bluetooth® communication unit64, which can act as noise spectrum pattern transmitting means and additional information acquiring means in accordance with the invention, communicates with various electronic control units (ECUs) such as a wiper ECU, an air conditioner ECU, a vehicle-to-vehicle communication ECU and the like via a Bluetooth® protocol or other proximity based protocol. By communicating with the ECUs, the Bluetooth® communication unit64acquires varied additional information such as an on/off state of wiper operation, on/off state of air conditioner operation, engine sound and exhaust sound from other vehicles running around the vehicle, and the like, and transmits a noise spectrum affixed with the acquired additional information to the server63.

In the server63, a telephone communication unit65, which can act as noise spectrum pattern receiving means in accordance with the invention, receives the noise spectrum pattern transmitted from the in-vehicle hands-free device62. A noise spectrum pattern unit66, which can act as noise spectrum pattern optimizing means in accordance with the invention, analyzes the noise spectrum pattern received from the in-vehicle hands-free device62by the vehicle can be detected, for example, by the cellular phone3, at S1. The detected present position of the vehicle is transmitted to the server4. Upon receipt of the noise spectrum pattern from the in-vehicle hands-free device2, the cellular phone3transmits the received noise spectrum pattern to the server63.

When the server63receives the present position of the vehicle and the noise spectrum pattern from the cellular phone3, a weather information transmission request is transmitted to the weather information delivery server. When the weather information delivery server receives the weather information transmission request from the server63, weather information is acquired at S12corresponding to the present position of the cellular phone3that transmitted the weather information transmission request. Then, the acquired weather information is transmitted to the server63.

When the server63receives the weather information from the weather information delivery server, the present position of the vehicle, the noise spectrum pattern received from the cellular phone3, and the weather information received from the weather information delivery server can be stored in association with one another at S13. The server63analyzes the data by the present position of the vehicle, noise spectrum pattern, and weather information. A stationary component, such as road noise, is left and non-stationary components, such as conversation sound from occupants, operating noise from wiper or air conditioner, engine sound and exhaust sound from other vehicles is canceled. An average noise spectrum pattern is generated. By removing non-stationary noise components, the noise spectrum patterns are thereby optimized. The present position of the vehicle, average noise spectrum pattern, and weather information are stored in correspondence with one another at S14.

The server63transmits the optimized noise spectrum pattern to the in-vehicle hands-free device62as described below. The in-vehicle hands-free device62transmits a present position detection and transmission request to the cellular phone3. When the request is received, the cellular phone3detects the present position of the vehicle at S1and the detected present position of the vehicle is transmitted to the server63.

When the server63receives the present position of the vehicle, a weather information transmission request is transmitted to the weather information delivery server. When the request is received, the weather information delivery server acquires weather information corresponding to the present position of the cellular phone3that transmitted the weather information transmission request at S21. The acquired weather information is then transmitted to the server63.

When the weather information is received by the server63, the average noise spectrum pattern, which is stored in correspondence with the present position of the vehicle received from the cellular phone3and the weather information received from the weather information delivery server, is selected at S22. The selected average noise spectrum pattern is transmitted to the cellular phone3. When received by the cellular phone3the received average noise spectrum pattern is transmitted to the in-vehicle hands-free device2. When received by the in-vehicle hands-free device2the received average noise spectrum pattern are input to the active noise control unit14and the noise cancellation unit15. Then, at S4, an inverted noise spectrum pattern is generated at the active noise control unit14and at the noise cancellation unit15at S4. A noise canceling signal is generated at S5based on the generated inverted noise spectrum pattern.

In the in-vehicle hands-free device62, when a transmitted voice signal, a road noise component, and an acoustic echo component are inputted as a transmit signal from the microphone7, the control unit5converts the inputted transmit signal from analog signal to digital signal at the first A-D conversion unit9and superimposes a noise canceling signal generated by the noise cancellation unit15on the transmit signal to cancel the road noise component. The control unit5then cancels the acoustic echo component at the echo cancellation unit16and converts the digital signal into an analog signal at the first D-A conversion unit10. The control unit then causes the Bluetooth® communication unit65to transmit a transmit signal that approximates the above described transmitted voice signal to the other party of telephone conversation via the cellular phone3.

It should be noted that the above construction may be modified such that, at the server63, the present position of the vehicle is received from the in-vehicle hands-free device62. In response to the reception of a noise spectrum pattern, the noise spectrum pattern received from the in-vehicle hands-free device62is optimized. The average noise spectrum pattern corresponding to the present position of the vehicle is then transmitted to the in-vehicle hands-free device62. The foregoing is a description of a construction that at the server63, weather information is acquired from the weather information delivery server and an average noise spectrum pattern is computed and stored with respect to each piece of acquired weather information such as fine weather, rainy weather, and the like. Instead, in accordance with the invention traffic information is acquired from a traffic information delivery server and an average noise spectrum pattern is computed and stored with respect to each piece of the acquired traffic information, such as a degree of traffic, a traffic jam, information about road work in a given section, and the like.

According to the fourth embodiment, the same operation as in the first embodiment is carried out. That is, the multiple different noise spectrum patterns corresponding to multiple different road surfaces are stored in the server63, not in the in-vehicle hands-free device62. Further, of the multiple different noise spectrum patterns, a noise spectrum pattern corresponding to the road surface on which the vehicle is presently running is determined by the server63, not by the in-vehicle hands-free device62. Therefore, the active noise control effect can be appropriately produced and road noise can be appropriately reduced even when noise spectrum patterns for determination are not stored locally. Since an average noise spectrum pattern with a stationary component left and a non-stationary component canceled is transmitted to the in-vehicle road noise controller62, it is possible to more appropriately reduce road noise and thus enhance accuracy.

As mentioned above, the present embodiment is constructed based on the first embodiment, that is, the present position of the vehicle is detected by the cellular phone3. Alternatively, the present embodiment may be constructed based on the second embodiment, that is, the present position of the vehicle is detected by the in-vehicle hands-free device42. Accordingly, the same action and effect can be obtained by causing the in-vehicle hands-free device42to transmit a noise spectrum pattern to the server4.

Other Embodiments

It will be appreciated that the invention is not limited to the above described embodiments, and can be modified or expanded, for example, as described herein below.

The external device need not be a cellular phone having a position detection function, and may be any other device, such as a personal digital assistant or an automobile navigation system, having a position detection function. Alternatively, the external device may be an automobile navigation system mounted in any other vehicle running in the vicinity of the vehicle. In such a case, the automobile navigation system mounted in the other vehicle can be caused to detect the present position of the vehicle by carrying out vehicle-to-vehicle communication between the automobile navigation system in the vehicle and that in the other vehicle. When the external device is an automobile navigation system, the position detection unit may be so constructed that it uses a GPS receiver, a geomagnetic sensor, a gyroscope, a distance sensor, or the like together. Further, the invention may be so constructed that the in-vehicle hands-free device and an external device or various ECUs are wirelessly connected together in accordance with any other wireless or wired communication standard or combination of standards.