JP2000028374A - Onboard navigation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the degradation of an image quality and to use a plurality of video sources without increasing a cable and a connector in an on-vehicle navigation system in which a display device and a navigation apparatus body are provided. SOLUTION: In a display device 2, a digital interface control part 21 which interfaces image data to he sent from a navigation apparatus body 1 is provided, a frame buffer 22 which displays the image data received by the digital interface control part 21 is provided, and a control processing part 25 is provided. In the navigation apparatus body 1, a frame buffer 14 which stores plotted data is provided, and a digital interface control part 17 which reads out the plotted data so as to be transferred to the display device 2 is provided. The digital interface control part 21 and the digital interface control part 17 are connected by a digital line 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle navigation system for detecting position information of a vehicle and displaying a road map and various screens as the vehicle travels.

[0002]

2. Description of the Related Art Conventional in-vehicle navigation systems include:
It has a navigation device body that has an input / output unit and a position detection unit of a storage medium, generates a map image and outputs it as a video signal (NTSC signal or RGB signal), and a display device that displays a screen based on the video signal. ing.

In this conventional vehicle-mounted navigation system, the navigation apparatus body also has an input section for a video signal from a TV tuner or a camera, and can switch between a map screen and a TV or camera screen.

[0004] The display device and the navigation device main body are
Connected by video signal.

[0005]

The navigation apparatus body stores display data in the form of digital signals. This is converted into an analog signal by DA conversion, and then output through a video analog switch or the like for switching between a television signal and a camera signal.

Therefore, the quality of an image is deteriorated as compared with the original digital signal due to conversion and switching.

In the case of an analog video interface, it is not possible to multiplex signals from a plurality of sources on a cable. Therefore, in order to enable the input of a plurality of sources, the number of cables and connectors corresponding to the number of sources is required, so that the time and effort required for connection are increased, and the device configuration is complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an in-vehicle navigation system which includes a display device and a navigation device main body, does not deteriorate image quality, and can use a plurality of video sources without increasing the number of cables and connectors. I do.

[0009]

Means for Solving the Problems and Effects of the Invention (1) An in-vehicle navigation system according to the present invention includes a display device and a navigation device main body, and the display device transmits image data transmitted from the navigation device main body. A first digital interface control unit for digitally interfacing with the first digital interface, a first frame buffer for expanding image data received by the first digital interface control unit, and a first frame buffer for the first digital interface and the first frame buffer. A central processing unit for executing control, wherein the navigation device main body includes a second frame buffer for storing drawing data, and a second digital interface control for reading out the drawn data and transferring the data to a display device. And the first digital interface. A scan control unit, between the second digital interface control unit is connected to a digital line (claim 1).

According to the above configuration, the display device can receive image data that can be displayed on the display from the navigation device body in digital form. Therefore, it is possible to prevent image deterioration due to transfer.

(2) The navigation device main body includes a second
The second digital interface control unit has an external input port connected to the digital interface control unit of
A digital video signal may be multiplexed and sent to a digital line (claim 2).

As described above, since the image data of a plurality of devices can be superimposed on the digital line, even if the number of external video devices increases, they can be connected in a cascade with the same interface, and the navigation device itself can be connected. It is not necessary to increase the number of input ports of the display device.

(3) The central processing unit of the display device may selectively request image transmission from a navigation device main body or a video device connected to an external input port. ).

[0014] According to this, since the image data is not sent from the navigation device main body and the video equipment connected to the external input port at the same time, the saturation of the digital interface can be prevented. Therefore,
This is effective when the capacity of the digital interface is limited.

(4) The image transferred from the navigation device main body and the video equipment connected to the external input port may correspond to a multi-window divided into screens.

With this configuration, when it is desired to split and display images from a plurality of sources, simultaneous transfer can be realized while suppressing an increase in the bandwidth of the interface. Therefore, the bandwidth of the digital interface can be used effectively.

(5) The display device includes a circuit for converting a digital audio signal into an analog audio signal and a speaker, and the navigation device body superimposes digital audio data on a digital interface. (Claim 5).

With this configuration, audio information (warning sound, music, etc.) to be notified from the navigation device main body can be played from a speaker placed on the display device side. Further, the video and audio lines conventionally wired in separate systems can be reduced to one.

(6) Preferably, the display device has a circuit for expanding a compressed digital audio signal, and the navigation device body has a circuit for compressing digital audio data. .

With this configuration, an increase in the bandwidth of the digital interface can be suppressed.

(7) It is preferable that a remote control unit is connected to the display device, and control information is exchanged by the remote control unit through a digital interface.

When operating the remote controller of the in-vehicle navigation system, the remote controller unit can be placed close to the driver together with the display device, so that the connection is simplified and the driver can operate easily. Further, since the signal of the remote control unit can be relayed into the navigation device main body by sharing the interface with the interface, the wiring becomes simpler than when the signal is directly input to the navigation device main body.

(8) It is preferable that the navigation apparatus main body prepares one or more images expected after the switching and prepares and transfers the images in advance before a command to switch the image is issued by operating the remote control unit. (Claim 8).

In the display in the on-vehicle navigation system, there are limited displays such as menu selection and map scrolling that require a quick response to the operation of the remote control unit. The switches on the unit are about three or four,
The transition screen to be prepared is limited.

In such a case, by preparing the selected image in advance, the response to the operation of the remote control unit can be accelerated. In addition, since the next operation is rarely performed immediately after the screen is switched, the next image can be prepared during that time.

(9) An in-vehicle navigation system according to the present invention includes a display device and a navigation device main body, wherein the display device has a first frame buffer for storing image data to be displayed on a display, and a signal from an external device. A first digital interface control unit that receives the command, and a drawing unit that develops a frame buffer in accordance with a drawing command sent from the navigation device body,
The navigation device body includes a second central processing unit,
A second digital interface control unit for transferring a drawing command from the second central processing unit to the display device, wherein the first digital interface control unit and the second digital interface control unit The sections are connected by a digital line (claim 9).

According to this system configuration, the frame buffer is eliminated from the navigation device body of the first aspect,
The drawing command is directly transferred from the navigation device body to the display device. In the display device, drawing is performed, so a drawing unit is required. For this reason, it is possible to eliminate the overlap of the frame buffer between the navigation device main body and the display device, and to reduce the overall cost. Further, since the data size of the drawing command is smaller than that of the image data, the bandwidth of the digital interface can be reduced as compared with the case of transmitting the image data.

(10) Preferably, the display device has a circuit for expanding a compressed digital audio signal, and the navigation device main body has a circuit for compressing digital audio data. .

With this configuration, an increase in the bandwidth of the digital interface can be suppressed.

[0030]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a functional block diagram of software of an on-vehicle navigation system. The on-vehicle navigation system includes a navigation device body 1, a display device 2, a digital bus 3 for connecting the navigation device body 1 and the display device 2, and Consists of

The display device 2 includes a CPU 25 for overall control such as pixel format and data transfer, a memory 24 for storing programs, a DIF (digital interface) control unit 21, a frame buffer 22 (sharing a chip with the memory 24). And a control circuit board 26 constituted by a video control unit 23 and a liquid crystal display 27.
And

The frame buffer 22 includes a DIF control unit 2
The pixel information corresponding to each pixel of the liquid crystal display 27, which is taken in through 1 is stored. Video control unit 23
Reads out the pixel information of the frame buffer 22 periodically at intervals of, for example, every 1/60 second and transfers it to the liquid crystal display 27. When the liquid crystal display 27 receives this information, the liquid crystal display 27 displays it in the color of the corresponding pixel. . Thus, a moving image is represented.

Depending on the specifications of the driver IC for driving the liquid crystal, there are a type having an analog input and a type having a multi-bit digital input. Video control unit 23
Generates an analog or digital video signal according to the specifications of the liquid crystal display 27,
7 is output.

As for the image information to be written into the frame buffer 22, when local setting (for example, setting of brightness and color) of the display device 2 is performed, the CPU is used.
25 generates data and writes it to the frame buffer 22.

In this embodiment, IEEE1394 is adopted as the digital interface. IEEE1394
According to the above, data can be transferred at a maximum transmission speed of 400 Mbps, so that when displaying about 640 × 480 pixels, when transferring 8 bits or 16 bits of data per pixel, transferring 60 images per second. And moving images can be transferred. Even when one pixel is composed of 16 bits or more of color, moving images can be transferred by reducing the image transfer speed to 30 sheets per second or the like.

In practice, the pixel size of a liquid crystal display is typically 400 × 240 or 320 × 240. The bit number of one pixel is 8 bits for a pseudo color, and 16 bits for an RGB expression or a YUV expression. In the case of an 8-bit pseudo color, it is converted into RGB information by a color palette at the exit of the DIF control unit 21 or the video control unit 23 of the display device 2. 1
Similarly, in the case of 6-bit YUV, RG is output from the DIF control unit 21 or video
It is converted to B information.

As the image data to be transferred, compressed image data may be used instead of image data having pixel information of 1 bit. For example, when the navigation device body 1 handles uncompressed image data, JP
The data is transferred to the display device 2 by performing compression using an image compression method such as EG. The function of this compression is CP
It may be realized by software of U or dedicated hardware may be prepared. If the navigation device main body 1 holds compressed data, the data may be transferred to the display device 2 as it is.

On the display device 2 side, if the image data sent from the digital interface is compressed, it is expanded and expanded on the frame buffer 22. This decompression function may be realized by software of the CPU, or dedicated hardware may be prepared.

On the other hand, the navigation device body 1 includes a locator 11 for detecting the position of the vehicle, a CPU 12, a map data storage device 13, a remote control input circuit 14, and a frame buffer for storing a map including the position of the vehicle from the vehicle position information and the map information. A drawing unit 15 for drawing on the frame 16, a frame buffer 16
Data (pixel data) of the digital bus 3
It has a DIF (digital interface) control unit 17 and a remote control unit 18 for converting into a format to be sent to the remote controller.

The locator 11 detects the position of the vehicle on the basis of output signals of sensors such as a wheel speed sensor, a direction sensor, and a GPS receiver. See, for example, JP-A-63-247612.

The CPU 12 reads the corresponding map information from the map data storage device 13 based on the position of the vehicle detected by the locator 11, and causes the drawing unit 15 to draw the map information on the frame buffer 16. Since a map is basically composed of straight lines, polygons, and characters, this drawing command includes drawing straight lines, filling polygons, transferring rectangles and small image data (such as landmarks), expanding character data, There are types such as scrolling.

The DIF control unit 17 causes the display device 2 to periodically read out the map image (pixel) information placed on the frame buffer 16 and convert it into a signal on a digital interface, ie, an IEEE1394 signal in this embodiment. The data is converted and sent to the digital bus 3. Information regarding display such as the format of image data and the number of pixels is adjusted by exchanging data between the navigation device main body 1 and the display device 2 or between other devices. At the time of this adjustment, information is exchanged on a common digital interface.

The DIF control unit 17 has two ports (input port and output port) as shown in FIG.
The output port is connected to the display device 2, and the input port is connected to an external video device such as a television tuner. The DIF control unit 17 mixes the digital image signal input from the input port and the digital image signal generated by the conversion by itself in the form of frequency multiplexing and sends the mixed signal to the output port. Specifically, subtract the transfer bandwidth (several tens of Mbps) used for external input from the transfer bandwidth of the digital interface (several hundred Mbps), and put your own output on the remaining bandwidth, It passes to the next device. In FIG. 1, the input port is provided on the navigation device main body 1, but may be provided on the display device 2.

FIG. 2 shows a connection state of the above-described on-vehicle navigation system. In this example, as an external video device, a TV tuner 4 having an IEEE1394 interface and a camera 5 are connected. The camera 5 has a DIF control unit similar to that described above, inputs the signal of the television tuner 4 to its input port, and multiplexes its own signal and the signal of the television tuner 4 to its output port to output. The signal output from the camera 5 enters the input port of the DIF control unit 17 of the navigation device main body 1, and all signals are multiplexed through the output port and supplied to the display device 2.

Since the signal lines can be connected in cascade in this manner, signals from a plurality of devices can be supplied to the display device 2 without increasing the number of connectors (if the TV tuner 4, the camera 5, the navigation device, etc.). When each signal of the main body 1 is collected on the display device 2, the display device 2 requires an input device having a plurality of ports, and the input device must increase the number of ports as the number of video devices increases. . Further, since no analog switch is interposed, images of any video equipment can be displayed without deterioration.

Further, the external video equipment such as the television tuner 4 and the camera 5 does not always transmit its own image data, but the video equipment is connected to the CPU 2 of the display device 2.
The image data is transferred only when the transfer of the display data is requested from 5. By doing so, it is possible to prevent a situation such as saturation of the digital interface, which occurs when all the video devices constantly send image data.

FIG. 3 is a diagram showing another embodiment of the invention for executing screen division. In this embodiment, each video device transfers image data corresponding to each area. For example, the television tuner 4 sends the image data of the portion A (FIG.
(See (a)), the camera 5 sends the image data of part B (see FIG. 3 (b)), and the navigation device body 1 sends the image data of part C (see FIG. 3 (c)). Display device 2
Creates an image of the entire display screen by combining the image data as shown in FIG. 3 (d) and displays it on the liquid crystal display.

FIG. 4 is a functional block diagram showing another embodiment of the display device 2. In this figure, an audio circuit 27 for D / A conversion of digital audio data, an amplifier 29 for amplifying an analog audio signal, and a speaker 30 are added.

When music or a warning sound is played from the navigation device main body 1 or when the TV tuner 4 plays TV sound, a digital audio signal is played on the digital interface on the source side. The display device 2 can receive audio data separately from the image data and sound the speaker. The digital interface shares the image data with the transferred image data, and performs the transfer using the remaining bandwidth.

The audio data may be compressed data. When data that has been compressed in advance, such as ADPCM data, is stored in the navigation device main body 1 or the like, the data can be directly transmitted to the digital interface. The display device 2 decompresses the compressed data using a decompression function and supplies the decompressed data to the audio circuit 28. The decompression function may be realized by software using a CPU, or may have dedicated hardware.

FIG. 5 is a view showing another embodiment in which the display device 2 is provided with a remote control unit 32 having switches for control. A remote control input circuit 31 corresponding to the remote control unit 32 is provided on the display device 2 side. The connection between the remote control unit 32 and the remote control input circuit 31 may be either wired or wireless.

In the case of wireless communication, a light receiving unit or a receiving unit is provided in the display device 2, and the connection of wires is only required for the display device 2 and the navigation device main body 1.

The content of the remote control input may be a local setting of the display device 2 (adjustment of hue or brightness, etc.) or an operation of the TV tuner 4, the camera 5, or the navigation device body 1.

In the embodiment in which the remote control unit 32 is provided, some expected images are transferred from the navigation device main body 1 to the display device 2 before switching the images in accordance with the operation of the remote control unit 32. The procedure will be described.

The navigation apparatus body 1 prepares in advance image data to be selected in response to an input from the remote control unit 32, and transfers this image data to the display apparatus 2 using the surplus bandwidth of the digital interface. . On the display device 2 side, if an image corresponding to the state of the operation of the remote control unit 32 is prepared beforehand, the display screen can be immediately switched to a new screen.

For example, when the menu screen is displayed, there are several options as follows. Since the contents of the options are determined, the number of images corresponding to the options is prepared to operate the remote control unit 32. A quick (less than 100 msec) reaction can be realized. Also,
Since the next operation is rarely performed immediately after switching the display (it takes time for humans to read the new screen)
The navigation device main body 1 that has received the operation input of the remote control unit 32 can prepare a new image in the meantime.

In the case of map scrolling, the procedure is as shown in FIG. During scrolling, the CPU 25 of the display device 2 acquires the next image of the scroll destination from the navigation device body 1 and stores it in the frame buffer 22 (step S1). As long as the scroll direction is the same, the procedure of displaying the image stored in the frame buffer 22 (steps S2 and S3), acquiring the next image, and storing it in the frame buffer 22 is repeated.

When the scroll direction changes, step S3
To S4 to display the currently displayed image (that is, the image stops for two frames). Then, the next image in the changed direction is acquired (Step S)
5). Hereinafter, the same procedure is performed. According to such an image preparation method, the display device 2 can cope with it only by preparing two screens of the currently displayed screen and the screen one scroll ahead.

In this system, the navigation device body 1
Not only the video equipment connected to the digital interface such as the TV tuner 4 and the camera 5,
As long as the method of preparing the image is supported, it can be supported.

FIG. 7 shows a functional block diagram of a car navigation system according to still another embodiment.

This on-vehicle navigation system is shown in FIG.
Compared to the in-vehicle navigation system of FIG.
The drawing command from the PU 12 is directly transferred to the display device 2. In the display device 2, a drawing unit 35 corresponding to the frame buffer 22 is provided.
Executes drawing in response to a drawing command sent from the digital interface.

By providing a drawing function on the side of the display device 2, it is possible to use not only the navigation device body 1 but also devices such as a TV tuner, a video camera, an air conditioner, and an audio device that do not have a display screen. Become. For example, functions such as display of the state of an air conditioner, substitution of an operation panel of an audio device, display of a television channel, and switching of settings can be realized.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of software of an in-vehicle navigation system.

FIG. 2 is a connection state diagram of the vehicle-mounted navigation system.

FIG. 3 is a diagram showing another embodiment of the invention for performing screen division.

FIG. 4 is a functional block diagram showing another embodiment of the display device.

FIG. 5 is a functional block diagram in which a display device is provided with a remote control unit having switches for control.

FIG. 6 is a flowchart showing a procedure for transferring some expected images from the navigation device main body to the display device in advance before switching images according to the operation of the remote control unit.

FIG. 7 is a functional block diagram of an in-vehicle navigation system according to still another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Navigation device main body 2 Display device 3 Digital bus 11 Locator 12 CPU 13 Map data storage device 14 Remote control input circuit 15 Drawing unit 16 Frame buffer 17 DIF (digital interface) control unit 18 Remote control unit 21 DIF (digital interface) control unit 22 frames Buffer 23 video controller 24 memory 25 CPU 26 control circuit board 27 liquid crystal display

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // G06F 13/38 350 G06F 13/38 350 F term (Reference) 2F029 AA02 AC12 AC16 5B069 AA12 BA04 BB14 BC02 HA19 LA02 LA08 5B077 AA23 BA01 NN02 5C082 AA21 AA27 AA31 AA37 BA14 BB01 BB15 CA62 CA64 CA72 CA76 MM02 MM05 MM10 5H180 AA01 BB06 FF22 FF25 FF27

Claims (10)

[Claims] 1. A display device comprising: a display device; and a navigation device main body, wherein the display device has a first digital interface control section for taking a digital interface with image data sent from the navigation device main body;
A first frame buffer that expands image data received by the digital interface control unit; and a central processing unit that controls the first digital interface and the first frame buffer. A second frame buffer for storing drawing data, and a second digital interface control unit for reading out the drawn data and transferring the data to a display device, wherein the first digital interface control unit; 2
And a digital interface control unit connected by a digital line. 2. The navigation device body has an external input port connected to a second digital interface control unit. The second digital interface control unit multiplexes a digital video signal according to the rules of the digital interface, and 2. The in-vehicle navigation system according to claim 1, wherein the information is sent to a line. 3. The in-vehicle navigation system according to claim 2, wherein the central processing unit of the display device selectively requests the transfer of an image to a navigation device main body or a video device connected to an external input port. . 4. The in-vehicle navigation system according to claim 2, wherein an image transferred from the navigation device body and a video device connected to the external input port corresponds to a multi-window divided into screens. 5. The display device includes a circuit for converting a digital audio signal into an analog audio signal and a speaker, and the navigation device body superimposes digital audio data on a digital interface. Item 4. An in-vehicle navigation system according to item 1. 6. The in-vehicle navigation system according to claim 5, wherein the display device has a circuit for expanding a compressed digital audio signal, and the navigation device body has a circuit for compressing digital audio data. 7. The in-vehicle navigation system according to claim 1, wherein a remote control unit is connected to the display device, and the remote control unit exchanges control information through a digital interface. 8. The navigation apparatus according to claim 1, wherein one or a plurality of images expected after the switching are prepared and transferred in advance before a command to switch the image is issued by operating the remote control unit. The in-vehicle navigation system according to claim 7, wherein 9. A display device, comprising: a navigation device main body; wherein the display device has a first frame buffer for storing image data to be displayed on a display, and a first digital interface control unit for receiving a signal from an external device. And a drawing unit that develops in a frame buffer in accordance with a drawing command sent from the navigation device body, wherein the navigation device body has a second central processing unit;
A second digital interface control unit for transferring a drawing command from the second central processing unit to a display device, the first digital interface control unit;
And a digital interface control unit connected by a digital line. 10. The in-vehicle navigation system according to claim 9, wherein said display device has a circuit for expanding a compressed digital audio signal, and said navigation device body has a circuit for compressing digital audio data.