Abstract:
A disclosed vehicle navigation apparatus enables the issuance of an accurate and quick guidance. Voice uttered by an occupant of a vehicle is collected by a voice collecting unit and transmitted to an external facility by a voice transmitting unit. The external facility generates destination information based on the received voice, and transmits the destination information back to a destination information receiving unit of the apparatus. Based on the received destination information, the apparatus issues a guidance. The apparatus further includes a destination extracting unit by which the voice collected by the voice collecting unit is subjected to voice recognition in order to extract a destination from the collected voice. A tentative guidance is then issued based on the extracted destination until the destination information is received by the destination information receiving unit from the external facility.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a vehicle navigation apparatus that receives destination information generated outside a vehicle via wireless communications and provides guidance instructions based on the received information. 
         [0003]    2. Description of the Related Art 
         [0004]    A navigation system for automobiles is known whereby an occupant of a vehicle communicates with an operator at a remote communication center, notifying the operator with a destination so that the operator can search a database for information about the destination and transmit the destination information back to the vehicle. In the vehicle, guidance instructions are provided based on the received destination information (see Japanese Laid-Open Patent Application No. 10-253377, for example). 
         [0005]    This system is advantageous compared with another system that provides guidance based solely on map information stored in a vehicle-mounted recording medium because the map information stored outside the vehicle enables the installation of a large-scale database, which in turn makes it possible to provide more precise guidance instructions. In other words, while the vehicle-mounted recording medium is subject to a number of size and cost limitations, a recording medium installed in an external facility suffers from less such limitations. Furthermore, by connecting the external facility to a content provider, for example, it also becomes possible to update the maps, names of locations and buildings, or other information such as coordinates in the external database quickly. As a result, guidance that is based on the most up-to-date information can be provided. 
         [0006]    However, because the communication between the vehicle and the external facility requires some time (including the time for the occupant, such as a driver, to convey a destination and the time for the vehicle to receive destination information in the form of an electric signal), a problem arises that the start of guidance is delayed compared with the guidance based solely on the map information stored in a vehicle-mounted recording medium. This problem may actually lead to a situation where the vehicle has moved in a direction opposite to the destination by the time the guidance is provided. 
       SUMMARY OF THE INVENTION 
       [0007]    It is therefore a general object of the present invention to overcome the aforementioned problem. A more specific object is to provide a vehicle navigation apparatus capable of providing an accurate and quick guidance. 
         [0008]    In one embodiment, the invention provides a vehicle navigation apparatus comprising a voice collecting unit configured to collect voice uttered by an occupant of a vehicle; a voice transmitting unit configured to transmit the voice collected by the voice collecting unit to a facility outside the vehicle; and a destination information receiving unit configured to receive destination information from the external facility. The destination information is created at the external facility based on the voice transmitted by the voice transmitting unit. The apparatus issues a guidance based on the destination information received by the destination information receiving unit. The apparatus further comprises a destination extracting unit configured to extract a destination from the voice collected by the voice collecting unit by subjecting the voice to voice recognition. A guidance based on the destination extracted by the destination extracting unit is provided until the destination information is received by the destination information receiving unit from the external facility. 
         [0009]    In a preferred embodiment, the guidance based on the destination extracted by the destination extracting unit may be provided until the guidance based on the destination information received by the destination information receiving unit is initiated, or until a recommended route based on the destination information received by the destination information receiving unit is generated. 
         [0010]    In accordance with these embodiments, an accurate and the most up-to-date route guidance can be provided because the guidance is based on the destination information generated at the external facility, where there are not so many constraints regarding the size or cost of a recording medium in which map information is stored as in the vehicle-mounted recording medium, allowing the storage of large volumes of data and making it possible to update the stored information quickly. While the communication between the vehicle and the external facility requires some time, resulting in the blank period before the start of guidance, voice uttered by the user is analyzed by voice recognition technology to extract information indicating a destination, and a tentative route guidance is provided based on the extracted destination. Thus, problems associated with delayed guidance can be overcome. 
         [0011]    In a preferred embodiment, the destination extracting unit is configured to convert the voice collected by the voice collecting unit into a text and configured to extract text information located before or after a specific keyword in the text as a specific destination. 
         [0012]    Thus, an accurate and fast guidance can be provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    These and other objects, features and advantages of the invention will be apparent to those skilled in the art from the following detailed description of the invention, when read in conjunction with the accompanying drawings in which: 
           [0014]      FIG. 1  shows an example of an overall configuration of a vehicle navigation apparatus according to an embodiment of the invention; and 
           [0015]      FIG. 2  shows a flowchart of typical steps performed by a navigation computer of the vehicle navigation apparatus of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]    In the following, the present invention is described by way of embodiments with reference made to the attached drawings. 
         [0017]      FIG. 1  shows an overall configuration of a vehicle navigation apparatus  1  according to an embodiment of the invention. The vehicle navigation apparatus  1  comprises a wireless communications device  10 ; a hands-free communication system  20 ; a GPS receiver  30 ; a memory  40 ; a human-machine interface (HMI)  50 ; and a navigation computer  60 . The arrows in the drawings indicate the main flows of information communication within a vehicle on which the apparatus is mounted. The communication may be carried out via multiplex communication lines and in accordance with an appropriate communication protocol, such as Controller Area Network (CAN), Body Electronics Area Network (BEAN), Audio Visual Communication-Local Area Network (AVC-LAN), or FlexRay. 
         [0018]    The wireless communications device  10  is configured to transmit and receive information to and from an information center  100  via a wireless base station  70  and a network  80 . Between the wireless communications device  10  and the wireless base station  70 , wireless communications may be performed using various technologies, such as a cellular phone network, a Personal Handy-phone System (PHS) network, a wireless local area network (LAN), Worldwide Interoperability for Microwave Access (WiMAX), satellite telephone technologies, and a beacon. The network  80  by which the wireless base station  70  and the information center  100  are connected is a wired network, such as a public switched telephone network (PSTN), a digital communication network (such as the Integrated Services Digital Network, or “ISDN”), or an optical fiber (However, the communications between the wireless base station  70  and the information center  100  may be based on a wireless technology). The wireless communications device  10  may be equipped with mechanisms that are equivalent to those of a cellular phone. Alternatively, a commercially available cellular phone may be communicatively connected with the vehicle via a mechanical connection, a wired connection, or a short-distance wireless transmission system such as a Bluetooth system, to provide the function of the wireless communication device  10 . The cellular phone is merely an example of the communication device and other devices may be used. In accordance with the present embodiment, the wireless communications device  10  is controlled by the navigation computer  60 . 
         [0019]    The information center  100  herein refers to a facility that provides various information services to the vehicle of a user (which may or may not be the driver) based upon a contract. The information center  100  includes a database  110  and a center-side communication unit  120 . The information center  100  may be operated by an automobile manufacturer and staffed with operators who perform various operations on the database  110  or the center-side communication unit  120 , as well as interacting with users over the phone. 
         [0020]    The hands-free communication system  20  may include a voice recognition microphone, a speaker, a telephone switch, and cellular phone cables mounted on the ceiling of the passenger compartment. By connecting a cellular phone to the system, a driver, for example, can communicate with the outside of the vehicle without holding the cellular phone in his hand. Alternatively, instead of connecting the cellular phone via cables, part of the mechanisms of the wireless communications device  10  may be shared for external communication purposes. Any other mechanism may be employed as long as it allows communication between the vehicle and an operator in the information center  100 . In accordance with the present embodiment, the hands-free communication system  20  is controlled by the navigation computer  60  and uses the HMI  50  for user interface. 
         [0021]    The GPS receiver  30  receives electromagnetic wave signals from a GPS satellite conveying data concerning time and the orbit of the satellite, and outputs such data to the navigation computer  60 . 
         [0022]    The memory  40  may be a recording medium such as a hard disc drive (HDD), a digital video (or versatile) disk (DVD), or a Compact Disc read-only memory (CD-ROM) in which map information is stored. The map information may specify road configurations in terms of nodes indicating intersections or the like and links connecting the individual nodes. The map information may include names of major buildings and places that can be a destination, and coordinates (latitudes and longitudes) of various facilities. 
         [0023]    The HMI  50  consists of a group of devices for providing an input/output interface between a user and the vehicle navigation apparatus. The devices may include a touch-panel display unit configured to enable a user to enter various data as well as presenting an image display; a microphone for voice input and output; a speaker; and a buzzer. The output content of the HMI  50  is determined by the navigation computer  60 , to which input operations made via the HMI  50  are provided. 
         [0024]    The navigation computer  60  may be a computer unit including a CPU to which a read-only memory (ROM) and a random access memory (RAM) are connected via buses. The navigation computer  60  may further include a recording medium such as a HDD or a DVD, an I/O port, a timer, and a counter. In the ROM, programs or data executed by the CPU may be stored. The navigation computer  60  includes a current position identifying unit  62 , a recommended route generating unit  64 , a route guidance unit  66 , and a destination extracting unit  68  as major functional blocks, which may be activated upon loading of the programs stored in the ROM by the CPU on the RAM where they are executed. 
         [0025]    The current position identifying unit  62  identifies the current position (latitude, longitude, and altitude) of the vehicle on which it is mounted by performing calculations based on time difference of electromagnetic wave signals received by the GPS receiver  30 . The current position of the vehicle may be corrected based on various information, such as the outputs of various sensors including a vehicle speed sensor and a gyro sensor, and various other information received via a beacon receiver and an FM multiplex broadcast receiver, for example. 
         [0026]    The recommended route generating unit  64  may generate a recommended route to a destination by the Dijkstra method. The route guidance unit  66  presents a navigation display or provide voice guidance via the HMI  50  in order to guide the vehicle along the recommended route. 
         [0027]    The function of the destination extracting unit  68  is described later. 
       Sending a Destination Search Request to Information Center  100   
       [0028]    In accordance with the present embodiment, a destination may be set by a user performing a touch operation via the HMI  50 , or by the user asking an operator at the information center  100  to conduct a destination search, using the hands-free communication system  20 . 
         [0029]    Thus, more accurate and more up-to-date route guidance can be provided based on accurate and the latest information available at the information center  100  than when a guidance is based solely on the map information stored in the memory  40 . This is due to the fact that, while the vehicle-mounted memory  40  is subject to many limitations in size and cost, the database  110  installed at the information center  100  is subject to less such limitations and can be larger in size or volume. Furthermore, by connecting the information center  100  with a content provider, for example, information about the road configurations, place names or building names as destination candidates, and their coordinates can be quickly updated, whereby guidance based on the latest information can be provided. Furthermore, because a destination is designated through communication, even a user not used to mechanical operations can operate the apparatus with confidence. 
         [0030]    In the following, a basic procedure for sending a request to the information center  100  to conduct a destination search is described. As a user performs a predetermined operation or enters a voice input via the HMI  50  for connection with the center, the navigation computer  60  instructs the wireless communications device  10  or the hands-free communication system  20  to call a pre-registered destination search request number or the like of the information center  100 . 
         [0031]    Upon establishing a connection with the information center  100 , the user designates a desired destination to the operator in the information center  100 , and asks him to perform a search and transmit relevant destination information back to the vehicle. 
         [0032]    The operator in the information center  100  searches the database  110  for the destination designated by the user, and sends back a search result (destination information, including coordinates) to the vehicle in the form of an electric signal. 
         [0033]    After the destination information is received on the vehicle, the recommended route generating unit  64  generates a recommended route from the current position identified by the current position identifying unit  62  to the coordinates of the destination received from the information center  100 . The route guidance unit  66  then presents a navigation display or issues a voice guidance via the HMI  50  in order to guide the vehicle along the recommended route. 
       Problem 
       [0034]    However, there is the aforementioned problem that, in the case of requesting the information center  100  to conduct a destination search, it takes longer before the start of actual route guidance due to the time required for the communications conducted between the vehicle and the information center  100  and other procedures. As a result, it is possible that the vehicle has traveled in a direction opposite to a desired destination when the guidance is issued. 
         [0035]    The problem is overcome by the present invention providing a tentative route guidance at the vehicle end in the blank time between the procedure to request a destination search by the information center  100  and the start of actual route guidance (or the reception of destination information from the information center  100 ). 
         [0036]    It is, however, troublesome if the user has to perform a touch operation or the like via the HMI  50  to set a destination solely for such a tentative route guidance during the blank time. 
       Tentative Route Guidance by Voice Recognition 
       [0037]    Thus, in the vehicle navigation apparatus  1  of the present embodiment, after the user has performed a predetermined operation or voice input for center connection, the content of speech (voice data) made with the hands-free communication system  20  or the like is fed to the navigation computer  60 . The entered speech content (voice data) is subjected to voice recognition by the destination extracting unit  68 , whereby a destination contained in the entered speech content is extracted. Based on the extracted destination, the recommended route generating unit  64  generates a temporarily recommended route based on which a tentative route guidance is provided. 
         [0038]    Various voice recognition technologies are known for converting voice data into a text, so that the description of the details of such a process is herein omitted. 
         [0039]    From the text-converted voice data, a destination may be extracted by the following method: 
         [0040]    A number of specific keyword phrases typically associated with a request concerning a destination are prepared. Examples of such keyword phrases are: “I wish to go to ***,” “To ***,” “The destination is ***,” “I&#39;m going to ***,” and “*** is my destination.” Then, the words in the portion (with asterisks) following (or preceding, in the case of the last example) the keyword phrases are extracted as a destination. 
         [0041]    Alternatively, the user may be required to perform some switching or touch operation at the beginning and end of a destination. In this way, the destination portion of voice data can be more accurately identified. 
       Control Flow 
       [0042]      FIG. 2  shows a flowchart of a typical process performed by the navigation computer  60 , which is initiated upon entry by a user of a predetermined operation or voice input for connection with the center. 
         [0043]    The navigation computer  60  instructs the wireless communications device  10  or the hands-free communication system  20  to establish a connection with the information center  100  (S 200 ). 
         [0044]    Upon establishing a connection with the information center  100 , the user starts communicating with an operator at the information center  100 . The voice data (user&#39;s voice) entered on the hands-free communication system  20  is transmitted to the information center  100  on a real-time basis (S 210 ) and is also fed to the navigation computer  60  (S 220 ). 
         [0045]    Following the entry of the voice data, the destination extracting unit  68  extracts a destination from the voice data as described above (S 230 ). Before destination information is received from the information center  100 , a tentative route to the destination extracted by the destination extracting unit  68  is generated and a tentative route guidance is issued based on the tentative route (S 240 , S 250 , and S 260 ). During this interval, the wireless communications device  10  is in a standby mode, waiting for destination information from the information center  100 . 
         [0046]    After a search process is performed in the information center  100  as described above and destination information is received from the information center  100 , a recommended route to the destination is generated based on the information received from the information center  100 , and a route guidance is issued. The guidance, which is based on the external information, continues until either the destination is reached or a procedure to set another destination (including the process of connecting with the center and the initial operation to set a destination via the HMI  50 ) is started (S 270 , S 280 , S 290 ). 
         [0047]    In accordance with the vehicle navigation apparatus  1  of the present embodiment, the problem of the extended blank time before the start of route guidance due to the time required for communications can be thus overcome, while the procedure of asking the information center  100  to conduct a destination search is still taken advantage of. 
         [0048]    Namely, by requesting the information center  100  to conduct a destination search, route guidance based on accurate and the latest information can be obtained. Because such a request is made through a verbal communication, a user not used to mechanical operations can make such a request with ease. During the blank time before route guidance starts, a destination contained in the speech content is extracted by voice recognition, and a tentative route guidance is provided based on the extracted destination. Thus, the problem of the vehicle traveling in an opposite direction to the destination during the blank time can be prevented. 
         [0049]    Thus, in accordance with the invention, an accurate and quick guidance can be issued. 
         [0050]    In another embodiment, the tentative route guidance based on voice recognition may be performed not until destination information is received from the information center  100  but until a recommended route is generated on the vehicle based on the destination information. In another embodiment, the tentative route guidance may be performed until route guidance based on destination information is actually started. 
         [0051]    Destination information is not limited to the coordinates of a designated destination. For example, a recommended route may be generated at the information center  100  based on the current position of the vehicle to a destination, and the recommended route thus generated outside the vehicle may be transmitted back to the vehicle. In this case, when initially establishing a connection between the vehicle and the information center  100 , and continually as the vehicle travels, a current position identified by the current position identifying unit  62  is transmitted to the information center  100 . 
         [0052]    In yet another embodiment, the search process within the information center  100  may involve a computer, rather than a human operator, performing voice recognition to extract a destination. 
         [0053]    The present invention may be utilized by automobile manufacturing industries or automotive component manufacturing industries. 
         [0054]    While the present invention has been described with reference to specific embodiments, the invention is not limited by such embodiments, and various changes or modifications may occur to those skilled in the art without departing from the scope of the invention. 
         [0055]    The present application is based on the Japanese Priority Application No. 2007-101934 filed Apr. 9, 2007, the entire contents of which are hereby incorporated by reference.