JP4609209B2 - Car navigation system - Google Patents

Description

  The present invention relates to an in-vehicle navigation device capable of reproducing audio information such as a music CD and recording the audio information by compressing the audio information.

  Many current vehicle-mounted navigation devices are provided with an audio function capable of reproducing audio information such as a music CD in addition to the navigation function. Furthermore, some audio information reproduced as in Patent Document 1 can be recorded in a large-capacity storage device such as a hard disk provided in the in-vehicle navigation device. As a result, the stored audio information can be reproduced at any time during subsequent driving.

Further, in the in-vehicle navigation device described in Patent Document 1, when recording audio information in the in-vehicle navigation device, it can be compressed and recorded. As a result, a lot of audio information can be recorded.
JP 2001-143369 A

  By the way, normally, in order to compress and record audio information as in the above-mentioned Patent Document 1, hardware such as a DSP (Digital Signal Processor) is provided separately from the CPU that processes the navigation function, and this compression processing is performed. Yes. This is because the compression process is a heavy load, and the same CPU cannot perform this compression process simultaneously with the navigation function process and the audio information reproduction. Therefore, if a function for compressing and recording is added, the cost increases correspondingly, and there is a demerit in terms of mounting hardware such as a DSP that performs compression processing. In order to prevent this problem, it is conceivable to increase the CPU performance and perform compression processing with a single CPU. However, increasing the CPU performance will eventually increase the cost of the CPU itself, so the cost will be much better. There is no.

  The present invention has been made in view of the above-described problems, and an object thereof is to reduce the cost of an in-vehicle navigation device capable of reproducing audio information and compressing and recording the audio information. .

In order to achieve the above object, the in-vehicle navigation device according to claim 1 includes an acquisition unit that acquires audio information from the outside, an audio information storage unit that directly stores the audio information acquired by the acquisition unit, and the audio information storage unit. There is a compression means for compressing the audio information stored in the memory, a compressed audio information storage means for storing the compressed audio information compressed by the compression means, and an instruction to reproduce the compressed audio information stored in the compressed audio information storage means In this case, the expansion means for expanding the compressed audio information, the audio information expanded by the expansion means, or the reproduction means for directly reproducing the audio information acquired by the acquisition means, and the process of navigating the traveling of the vehicle. In an in-vehicle navigation device comprising a navigation control means,
The navigation control means, the compression means, and the reproduction means are realized by a common CPU, and the processing performed by the navigation control means and / or the reproduction means when the compression means compresses the audio information. A determination means for determining whether the current load status of the CPU is small or large with reference to whether or not the processing performed by
The compression means compresses the audio information only when the determination means determines that the current load status of the CPU is small, and the audio information storage means is independent of the load status of the CPU, and Without depending on the progress of the compression process in the compression means,
When audio information is acquired by the acquisition means, the audio information is continuously stored as it is.

  As described above, since the compression process is performed when the load state of the CPU is small, it is not necessary to separately provide hardware for the compression process and it is not necessary to improve the performance of the CPU. Thereby, cost can be held down.

Furthermore, even when the load on the navigation control means is large, the audio information can be stored as it is, and then the audio information can be compressed when the load on the navigation control means becomes small.

The in-vehicle navigation device according to claim 2 , wherein the compression unit stops the compression when the determination unit determines that the current load state of the CPU is large while the audio information is being compressed, and thereafter When it is determined that the current load state of the CPU is small, the compression is restarted from the point where the compression is stopped. Thereby, even if the load state of the CPU fluctuates during compression, all audio information can be finally compressed.

The in-vehicle navigation device according to claim 3 , wherein when the determination unit performs at least one of the specific process among the processes of reproducing the audio information and navigating the vehicle, the load state of the CPU is large. It is characterized by determining. For example, when a specific processing in the process of navigating the travel of the reproduction or the vehicle audio information by the performance of the CPU, becomes high load conditions, there is a possibility to occur a disadvantage for these processes when the compression processing at this time . Claim 3 assumes such a case.

The vehicle-mounted navigation device according to claim 4 , wherein the current load situation of the CPU is large when the determination unit performs a specific process among the processes of reproducing the audio information and navigating the traveling of the vehicle. It is characterized by determining.

  This is considered to be due to the fact that the CPU load is increased to some extent when audio information is played back in a CPU generally used in current in-vehicle navigation devices. In addition to this, when a specific navigation process is being performed, it is considered that the CPU load is large as a whole. In this case, the compression process is not performed. This is because if the compression process is forcibly performed, basic navigation functions such as a delay in the generation timing of navigation guidance voice may not be performed normally.

  On the other hand, when only one of the specific processes is performed among the processes for reproducing audio information and navigating the vehicle, the load on the CPU is small, as viewed from the CPU generally used in the current in-vehicle navigation device. In this case, the audio information can be compressed.

An in-vehicle navigation device according to claim 5 is a setting means for setting a departure point and a destination, a map data storage means for storing map data, a position detection means for detecting the current location of the vehicle, a display unit, and the vehicle Vehicle speed detecting means for detecting the vehicle speed of the vehicle, wherein the navigation control means searches for an optimum route from the starting point to the destination set by the setting means using at least the map data, and the optimum route It performs a process of creating guidance data for guiding said vehicle along a processing for displaying the map data location near the vehicle on the display unit, and a processing for scrolling the screen of the display unit Among the processes for navigating the travel of the vehicle, the specific process includes a process for searching for the optimum route, a process for creating the guidance data, and the vehicle is faster than a reference speed. Processing for displaying the map data location near the vehicle on the display unit when moving at speed, characterized in that it contains in at least one of processing for scrolling the screen of the Display section. This is because these processes are generally considered to have a heavy load among the navigation processes.

The in-vehicle navigation device according to claim 6 is characterized in that the compression means starts compression of the audio information after a predetermined time has elapsed since the storage of the audio information was started in the audio information storage means .

The in-vehicle navigation apparatus according to claim 7, wherein the acquisition unit acquires the audio information from a music CD, and the compression unit stores data for one track of the music CD in the audio information storage unit. When this is done, compression of the audio information is started .

The in-vehicle navigation device according to claim 8, wherein the acquisition unit acquires the audio information from a music CD, and the compression unit stores data for all tracks of the music CD in the audio information storage unit. When this is done, compression of the audio information is started .

(First embodiment)
Hereinafter, a first embodiment of an in-vehicle navigation device according to the present invention will be described. In the in-vehicle navigation device of the present invention, navigation processing, reproduction of audio information such as a music CD, and compression recording are performed by one CPU, and at this time, audio information is compressed when the load on the CPU is small. It is said. In the first embodiment, whether or not the load on the CPU is small is determined by whether or not a predetermined process that is considered to be heavy is being performed.

  FIG. 1 is a block diagram showing the overall configuration of the in-vehicle navigation device 100 of the present embodiment. As shown in the figure, the in-vehicle navigation device 100 includes a position detector 1, a map data input device 6, an operation switch group 7, an external memory 9, a display device 10, an audio output device 11, a remote control sensor 12, a remote control 13, a CD drive. 14 and a control circuit 8 connected thereto. Each component will be described below.

  The position detector 1 includes a known geomagnetic sensor 2, a gyroscope 3, a distance sensor 4, and a GPS receiver 5 for GPS (Global Positioning System) that detects the position of the vehicle based on radio waves from a satellite. Have. Since these have errors of different properties, they are configured to be used while being complemented by a plurality of sensors. Depending on the accuracy of each sensor, the position detector 1 may be constituted by a part of the above-described parts, and a steering rotation sensor (not shown), a vehicle speed sensor for each rolling wheel, or the like may be used. The current position of the vehicle is detected by the position detector 1, and the control circuit 8 can recognize, for example, where the vehicle is traveling on the searched route when performing route guidance. Whether or not the vehicle is traveling along the route can be determined.

  The map data input device 6 displays road map data indicating the connection structure of roads, background data for displaying backgrounds related to topography and facilities, and place names when displaying road maps using the road map data. For this purpose, various types of map data such as character data are input to the control circuit 8. The map data input device 6 includes a storage medium for storing the above-described map data. As the storage medium, a DVD-ROM or a hard disk is generally used because of the amount of data, but other memory cards or the like are used. A storage medium may be used.

  Here, the map data stored in the storage medium of the map data input device 6 will be briefly described. First, the road map data includes node data regarding points where a plurality of roads intersect, merge and branch, and link data regarding roads connecting the points. The node data is composed of data such as node ID, node coordinates, node name, link ID of all links connected to the node, intersection type, etc. The The link data consists of data such as a link ID with a unique number for each road, link length, start and end coordinates, road type such as expressway and general road, road width, and link travel time. Yes.

  The background data is configured as data in which each facility or terrain on the map is associated with the corresponding coordinates on the map. Regarding the facility, data such as a telephone number and an address are also stored in association with the facility. The character data is used to display place names, facility names, road names, and the like on a map, and is stored in association with coordinate data corresponding to the positions to be displayed.

  Therefore, a map including roads can be displayed by combining background data and character data with this road map data. In addition to displaying a map, the road map data is used to give the shape of a road when performing map matching processing, and is used to search for a guide route to a destination.

  For example, a touch switch or a mechanical switch integrated with the display device 10 to be described later is used as the operation switch group 7. For example, a starting point and a destination when searching for a route are set, or the CD drive 14 is set. Is used to instruct the reproduction of the music CD inserted in the recording medium or the reproduction of the compressed audio information recorded in the external memory 9 described later.

  The external memory 9 includes a storage medium such as a memory card or a hard disk. The external memory 9 stores various data such as text data, image data, and audio data stored by the user. As will be described later, the audio information input from the CD drive 14 is temporarily stored together with the reproduction, and is also stored in the external memory 9 after being compressed.

  The display device 10 is configured by, for example, a liquid crystal display, and is usually generated on the screen of the display device 10 by the own vehicle position mark corresponding to the current position of the vehicle and the map data input from the map data input device 6. A road map around the subject vehicle is displayed. In addition, various screens such as a menu screen and a setting screen are displayed on the display device 10 by operating the operation switch group 7.

  The audio output device 11 includes a speaker, an audio amplifier, and the like, and is used when performing audio guidance or the like. Further, it is also used for reproducing audio information of a music CD recorded in the CD drive 14 to be described later and audio information recorded by compressing it.

  The in-vehicle navigation device 100 according to the present embodiment includes a remote control terminal (hereinafter referred to as a remote controller) 13 and a remote control sensor 12. It is possible to perform navigation operations.

  The CD drive 14 inputs audio information stored in the music CD to the control circuit. The audio information input here is played back or compressed and recorded. In addition to the CD drive 14, any device that can input audio information may be used. For example, a device that can also be used as a DVD drive or a device that can also input audio information stored in the MD may be used.

  The control circuit 8 is configured as a normal computer, and includes a well-known CPU, ROM, RAM, I / O, and a bus line for connecting these configurations. In the ROM, a program to be executed by the control circuit 8 is written, and according to this program, the CPU performs various arithmetic processes using the respective units. Specifically, for example, the optimum route from the starting point to the destination is searched. This calculates the passage cost indicating the ease of passage for each link and node constituting the road map data described above. This passing cost is calculated according to the characteristics of each link (link length, road type, road width, etc.) and the types of straight travel and right / left turn at each node. Then, for an arbitrary route from the departure point to the destination, a route that minimizes the added value of the passing cost of each link and each node constituting each route is searched using a route search method such as the Dijkstra method. To do. Thereafter, guidance data for guiding the vehicle along the searched route is created. Specifically, data in which a point to be guided is associated with guidance data (for example, “Please turn right at the next intersection”) is created.

  Further, the control circuit 8 determines the current location of the vehicle by performing map matching on the road with the estimated current location of the vehicle detected by the position detector 1 at regular time intervals. Then, map data around the current location is read from the map data input device 6, and the map data is displayed together with a mark indicating the current location so that the current location is at the center of the display device 10. That is, while the vehicle is traveling, the control device 8 displays a map centered on the current location. Furthermore, when there is an instruction to scroll the screen from the user, the scroll data is displayed while reading out the map data in the direction to be scrolled from the map data input device 6.

  Further, the control circuit 8 performs compression processing of uncompressed audio information stored in the external memory 9 when its own load state is small. An example of the compression method is MP3. Details of the processing at this time will be described later using a flowchart.

  Further, when there is an instruction to reproduce music from the user, the control circuit 8 directly reads out and reproduces audio information recorded on the music CD inserted in the CD drive 14 or stores it in the external memory 9. The compressed audio information is decompressed and played back. In the present embodiment, when a music CD is inserted into the CD drive 14, the music CD is automatically played back.

  Next, processing for executing or stopping audio information compression processing according to the processing status of the CPU of the control circuit 8, which is a feature of the present invention, will be described with reference to the flowchart of FIG.

  The process starts when a music CD is inserted into the CD drive 14. First, in step S101, CD data (audio information) stored in the music CD is read. In step S102, the CD data is reproduced and output to the audio output device 11 as audio. In accordance with this reproduction process, the CD data reproduced in step S103 is stored in the external memory 9 as it is.

  On the other hand, in step S110, it is determined whether the processing status of its own CPU is small or large. When it is determined that the load status is small, the audio information stored in the external memory 9 is read out in step S108, the compression process is executed, and the audio information is stored in the external memory 9 again. On the other hand, when it is determined that the load condition is large, the compression process is stopped in step S109. When the compression is stopped in the middle of the compression, the portion of the stopped data is stored, and when the compression process is executed again, the compression is resumed from the stopped position. Thus, compression can be performed efficiently.

  Here, it is determined in steps S104 to S107 whether the load state of the CPU of the control circuit 8 is small or large. The processes described in steps S104 to S107 are considered to have a heavy CPU load, and when one of these processes is being performed, it is determined that the CPU load condition is large. Conversely, when none of these processes is performed, it is determined that the load status of the CPU is small.

  Specifically, it is determined in step S104 whether the vehicle speed is equal to or higher than a reference value. If the vehicle speed is high, the degree of change of the current location becomes large. Accordingly, the map data is frequently read from the map data input device 6 to change the map displayed on the display device 10. Therefore, when the vehicle speed is equal to or higher than the reference value, it is considered that the load state of the CPU is large.

  In step S105, it is determined whether the map is being scrolled. When the map is scroll-displayed, the speed of reading the map data from the map data input device 6 becomes faster than usual, and the processing for displaying it on the display device 10 must also be accelerated. Therefore, when the map is being scrolled, it is considered that the load on the CPU is large.

  In step S106, it is determined whether a route search is in progress. As described above, when the user sets the departure point and the destination, the optimum route from the departure point to the destination is searched. For this search, a cost is assigned to each link and node constituting the road map data, and a minimum cost route is searched for a plurality of routes from the starting point to the destination by a method such as the Dijkstra method. There is a need to. Therefore, when the route is being searched, the load state of the CPU is considered to be large.

  In step S107, it is determined whether guidance data is being created. As described above, in order to create guidance data, it is necessary to determine where guidance is required on the searched route, and to determine what guidance is to be provided when it is determined that guidance is necessary. Therefore, when the guide data is being created, it is considered that the load status of the CPU is large.

  In step S111, it is determined whether or not the compression of all tracks of the music CD has been completed. If it has not been completed, the process returns to step S101 again and the above-described processing is repeated. On the other hand, when all the tracks have been compressed, the process is terminated.

  As described above, the in-vehicle navigation device 100 according to the present embodiment temporarily stores the audio information as it is along with the reproduction of the music CD. This audio information is compressed and stored again only when the CPU does not perform processing (steps S104 to S107) that is considered to be heavy. That is, a single CPU can be used for navigation processing, audio information reproduction processing, and audio information compression recording processing. As a result, no hardware such as a DSP is used to perform the compression process, so that the cost can be reduced.

  In this embodiment, when the music CD is played back in step S103, the data is stored as it is, and when step S110 is satisfied, the compression process is performed immediately. However, the present invention is not limited to this. For example, the processing after step S104 is performed after a lapse of a certain time after starting the storage in step S103, or the data for one track of the music CD is stored in step S103. You may perform the process below S104 later. Alternatively, the data for all tracks of the music CD may be stored as is, and then the compression process may be performed in step S104 and thereafter.

  In addition to the processing (steps S104 to S107) that is considered to have a high CPU load shown in the present embodiment, if there is a process that is considered to have a high CPU load, the compression processing is executed in consideration of the processing. You may make it switch a stop.

(Second embodiment)
Next, a second embodiment of the in-vehicle navigation device according to the present invention will be described. In the first embodiment, a process in which the CPU load of the control circuit 8 is considered to be large is assumed in advance, and whether the load state of the CPU is small or large is determined depending on whether or not the process is being performed. In the second embodiment, priorities are assigned in advance to the processes performed by the CPU, and the CPU preferentially performs processes (tasks) with high priority. Here, as a method of assigning priorities, the priority of tasks requiring real-time properties is increased. Therefore, for example, when considering navigation processing such as displaying a map around the current location of the vehicle, audio information reproduction processing, and audio information compression processing, depending on the type of navigation processing, audio information reproduction processing and navigation processing The priority is set from large to small in the order of audio information compression processing. This is because the real-time property is considered to decrease in these order. Therefore, when the CPU is frequently used in audio information reproduction processing and navigation processing, the audio information compression processing task is not easily reached. On the other hand, when the CPU is being used much in audio information reproduction processing and navigation processing, the number of times the audio information compression processing task having a lower priority is reached increases.

  Therefore, in this second embodiment, the time interval for the audio information compression processing task is monitored to determine whether the CPU load status is small or large based on the time interval. If it is determined that the load status of the CPU is large, the CPU does not perform the compression process even when the task of the audio information compression process is reached. This is because once a task is executed, a certain amount of time is spent on the task, which may hinder audio information reproduction processing and navigation processing. Hereinafter, details of the present embodiment will be described with a focus on differences from the first embodiment.

  As the vehicle-mounted navigation device of the present embodiment, the vehicle-mounted navigation device 100 having the configuration shown in FIG. 1 is used as in the first embodiment. The operation of each part shown in the figure is basically the same as that of the first embodiment, and thus the description thereof is omitted. However, as described above, there is a method for determining whether the load state of the CPU of the control circuit 8 is small or large. Different. Hereinafter, this determination process will be described with reference to the flowcharts of FIGS. 3 and 4 correspond to steps S110 (steps S104 to S107) and steps S108 and S109 in FIG. Therefore, other processes (steps S101 to S103, S111) are the same as those in the first embodiment. That is, first, the CD data inserted in the CD drive 14 is read in step S101, and is reproduced in step S102. At the same time, in step S103, the CD data is sequentially stored in an uncompressed state. Thereafter, compression processing of uncompressed audio information is performed in accordance with the processing of FIGS.

  First, when the audio information reproduction process and the navigation process are vacant, the CPU of the control circuit 8 tries to perform a compression process task. Here, first, in step S201, a monitor task described later is called. Here, the monitor task is a task for monitoring the time interval spent by the CPU on the compression processing task, and is specifically performed according to the flowchart of FIG.

  In step S301, it is determined whether the monitoring timer is longer than a predetermined time Tms. The monitoring timer is a timer that measures the time from when the CPU performed the task of the previous compression process. If the monitoring timer is smaller than the predetermined time Tms, the process proceeds to step S303. If the monitoring timer is smaller than the predetermined time Tms, it means that the CPU can spend the compression processing task relatively frequently, that is, the load state is small. In this case, in step S303, a stop flag for determining whether or not to execute the compression processing task is reset (= 0). On the other hand, when the monitoring timer is larger than the predetermined time Tms, the process proceeds to step S302. Here, the fact that the monitoring timer is larger than the predetermined time Tms means that the CPU spends a long time for processing other than the compression processing, that is, the load state is large. In this case, the stop flag is set (= 1) in step S304. Thereafter, the monitoring timer is reset in step S304, and the monitoring task process is terminated.

  Returning to the process shown in FIG. 3 again, it is determined in step S202 whether or not the stop flag is set (= 1) by the monitoring task described above. If it is not set here, it is determined that the load on the CPU is small, and the compression process is executed in step S203. On the other hand, when the stop flag is set, it is determined that the load state of the CPU is large, and this task is terminated without executing the compression process. This is because even if processing with high priority is given priority, once compression processing is executed, a certain amount of time is consumed, which may hinder processing with high priority.

  The above processing is performed until compression for all tracks of the music CD is completed (step S111 in FIG. 2).

  As described above, in the present embodiment, it is determined whether the load state of the CPU is small or large by monitoring the time interval that the CPU spends on the task of compression processing. The audio information compression process is executed when the load on the CPU is small. Thereby, the compression processing of audio information can be performed in combination with other processing by one CPU. That is, it is not necessary to use another hardware such as a DSP for the compression processing of the audio information, so that the cost can be reduced.

1 is a block diagram showing an overall configuration of an in-vehicle navigation device 100 according to a first embodiment and a second embodiment. 5 is a flowchart showing processing for executing or canceling audio information compression processing according to the processing status of the CPU of the control circuit 8 performed by the in-vehicle navigation device 100 of the first embodiment. 10 is a flowchart showing audio information compression processing tasks performed by the CPU of the control circuit 8 according to the second embodiment. It is a flowchart which shows the task which the CPU of the control circuit 8 of 2nd Embodiment monitors the time interval which self spent for the task of the compression process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Car-mounted navigation apparatus 1 Position detector 2 Geomagnetic sensor 3 Gyroscope 4 Distance sensor 5 GPS receiver 6 Map data input device 7 Operation switch group 8 Control circuit 9 External memory 10 Display apparatus 11 Voice output device 12 Remote control 13 Remote control sensor 14 CD drive

Claims (8)

Acquisition means for acquiring audio information from outside;
Audio information storage means for directly storing the audio information acquired by the acquisition means;
Compression means for compressing audio information stored in the audio information storage means ;
Compressed audio information storage means for storing compressed audio information compressed by the compression means;
Decompression means for decompressing the compressed audio information when there is an instruction to reproduce the compressed audio information stored in the compressed audio information storage means;
Reproduction means for reproducing the audio information expanded by the expansion means or the audio information directly acquired by the acquisition means;
In a vehicle-mounted navigation device comprising a navigation control means for performing a process of navigating the traveling of a vehicle,
The navigation control means, the compression means and the reproduction means are realized by a common CPU,
When the compression unit compresses the audio information, the current load status of the CPU is determined based on whether the process performed by the navigation control unit and / or the process performed by the reproduction unit is normally performed. Is provided with a determination means for determining whether the value is small or large,
The compression means compresses the audio information only when the determination means determines that the current load status of the CPU is small, and the audio information storage means is independent of the load status of the CPU, and An on-vehicle navigation device characterized in that, when audio information is acquired by the acquisition unit, the audio information is continuously stored as it is without depending on the progress of compression processing in the compression unit. The compression unit stops the compression when the determination unit determines that the current load state of the CPU is large while the audio information is being compressed, and then the current load state of the CPU is The in-vehicle navigation device according to claim 1 , wherein when it is determined that the compression is small, the compression is restarted from the point where the compression is stopped. The determination means according to the running of reproduction and the vehicle of the audio information when performing at least one of the identification processing of the processing to navigate, and judging a load condition of said CPU is large Item 3. The vehicle-mounted navigation device according to Item 1 or 2 . It said determination means, wherein the time to, and judging the current load status of the CPU is large the reproduction of the audio information, and has a travel of the vehicle by performing a specific process among the processes navigating Item 4. The in-vehicle navigation device according to item 3 . A setting means for setting a starting point and a destination,
Map data storage means for storing map data;
Position detecting means for detecting the current location of the vehicle;
A display unit;
Vehicle speed detecting means for detecting the vehicle speed of the vehicle,
The navigation control means uses at least the map data to search for an optimum route from the starting point to the destination set by the setting means, and for guiding the vehicle along the optimum route performs a process of creating the data, a process of displaying the map data location near the vehicle on the display unit, and a processing for scrolling the screen of the display unit,
Among the processes for navigating the travel of the vehicle, the specific process includes a process for searching for the optimum route, a process for creating the guidance data, and the vehicle when the vehicle moves at a speed faster than a reference speed. the process of displaying on the display unit a map data around the current position, vehicle according to claim 3 or 4, characterized in that it contains in at least one of processing for scrolling the screen of the display unit Navigation device. The in- vehicle apparatus according to claim 1, wherein the compression unit starts compression of the audio information after a predetermined time has elapsed since the audio information storage unit started storing the audio information. Navigation device. The acquisition means is for acquiring the audio information from a music CD,
6. The compression unit starts compression of the audio information when data for one track of the music CD is stored in the audio information storage unit. In- vehicle navigation device. The acquisition means is for acquiring the audio information from a music CD,
6. The compression means starts compression of the audio information when data for all tracks of the music CD is stored in the audio information storage means. In- vehicle navigation device.

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