JP6642520B2 - Vehicle speed limit display device and method - Google Patents

Description

  The present invention relates to a speed limit display device and a method for displaying a speed limit specified by a road sign present in front of a host vehicle.

As this kind of vehicle speed limit display device, for example, a sign recognition display device has been proposed in Patent Document 1.
The sign recognition display device of Patent Literature 1 includes a sign recognition unit that recognizes a road sign included in an image captured by a camera, a speed limit information acquisition unit that acquires speed limit information by a navigation system, and repeatedly receives these. A display device for displaying information on the speed limit.

  The sign recognition display device disclosed in Patent Document 1, for example, displays a sign when the speed limit specified by the speed limit information acquisition unit from the navigation system is displaying, for example, 60 km / h on the display device. When the recognition unit recognizes a road sign designating a speed limit of 40 km / h, the display control unit gives priority to a speed limit of 40 km / h designated by the road sign and causes the display device to display the speed limit (Patent). Paragraph [0025] in Document 1).

  With this, even when the driver cannot recognize the road sign indicating the speed limit specified for the entered road when the vehicle enters the road where the speed limit is different from before, even if the driver cannot recognize the road sign, The driver can recognize the specified correct speed limit preferentially through the display device.

  However, Patent Literature 1 does not assume the timing at which the display control unit preferentially displays the speed limit specified by the road sign on the display device other than the timing when the vehicle passes the road sign. However, there is no technical idea that the display content of the display device is changed except for the timing.

  Then, if the speed limit becomes lower than the speed before passing when the vehicle has passed the road sign while the vehicle is traveling, the display on the display device will be limited to the time when the vehicle has passed the road sign. Since the display will be changed to a speed limit lower than the speed, it is possible that the driver may start deceleration only after passing the road sign so that the speed will be less than the speed limit specified for the road after the passage. become.

  That is, in Patent Literature 1, when the own vehicle passes a road sign while traveling, the timing at which deceleration is started so that the vehicle speed of the own vehicle becomes equal to or less than the speed limit may be delayed. There is a possibility that the start timing of the acceleration / deceleration of the vehicle cannot be guided to an appropriate timing, and there is room for improvement from the viewpoint of improving safety.

JP 2017-45194 A

  The present invention has been made in view of such a problem, and even when the own vehicle passes through a position where the speed limit changes halfway during traveling, the start timing of the acceleration and deceleration of the own vehicle by the driver is appropriately adjusted. It is an object of the present invention to provide a vehicle speed limit display device and a method thereof that can guide timing and improve safety.

The present invention is a speed limit display device that displays speed limit information on a speed limit specified by a road sign present in front of the host vehicle, and a speed limit information obtaining unit that repeatedly obtains speed limit information based on the road sign. and display means for displaying the acquired the speed limit information, new speed limit which is the speed limit information newly acquired and the previous speed limit specified by the last speed limit information is last acquired the speed limit information and a comparing means for comparing the magnitude of the new speed limit specified by the information, said display means displays on the SL new speed limit information in accordance with the difference between the previous speed limit and the new speed limit It is intended to change the timing of, further said display means, maintaining the display of the previous speed limit information before displaying at least the new speed limit information DOO In, the new speed limit is lower than the previous speed limit, characterized in that the new speed limit for displaying the new speed limit information at an earlier timing than in the case greater than the previous speed limit.

  According to the above configuration, even when the vehicle travels through a position where the speed limit changes halfway, the start timing of acceleration / deceleration of the vehicle by the driver can be guided to an appropriate timing, and the safety can be improved. Can be improved.

As an aspect of the present invention, when the new speed limit is lower than the previous speed limit, the display means displays the new speed limit information at an earlier timing as the difference between the previous speed limit and the new speed limit is larger. To display.

As an aspect of the present invention, when the new speed limit is lower than the previous speed limit , the display means displays the new speed limit information at the time when the comparison result by the comparing means comes out, while displaying the new speed limit. If the speed is higher than the previous speed limit, the new speed limit information is displayed when the vehicle reaches the position of the road sign .

  According to the above configuration, the point in time when the comparison result by the comparing means is obtained corresponds to the earliest timing among the timings at which the new speed limit information can be displayed. Therefore, when the new speed limit is lower than the previous speed limit, the new speed limit information is displayed at such an early timing as possible, so that the speed limit of the traveling road can pass through the road sign. Accordingly, the time (distance) for decelerating the vehicle in preparation for changing to the new speed limit lower than the previous speed limit (current speed limit) until the vehicle passes a road sign is set. Can be sufficiently secured.

According to the above configuration, when the new speed limit is higher than the previous speed limit, even if the own vehicle recognizes the presence of the road sign in front of the road sign, the display means may cause the own vehicle to reach the position of the road sign. Until the new speed limit is displayed, the new speed limit information is displayed for the first time when the vehicle reaches the vehicle. The start of the acceleration of the own vehicle can be prompted.

  As an aspect of the present invention, the display means displays both the new speed limit information and the previous speed limit information until the vehicle reaches the position of the road sign.

  According to the above configuration, by displaying the new speed limit information until the vehicle reaches the position of the road sign, in the meantime, the speed limit is higher than before after the vehicle has passed the position of the road sign. In preparation for the vehicle being lowered, the driver can be prompted to decelerate the vehicle. Furthermore, the driver continues to display not only the new speed limit information but also the previous speed limit information (the speed limit of the road on which the vehicle is currently traveling) until the vehicle reaches the position of the road sign. While being able to accurately grasp the previous speed limit information, it is intuitive to the driver that the vehicle is currently traveling at a position immediately before the speed limit changes from the previous speed limit to the new speed limit. , Can be visually recognized.

As an aspect of the present invention, the display means displaces and superimposes the display of the previous speed limit so as to be located on the near side of the display of the new speed limit.

Also this invention, the previous speed limit is speed limit information obtaining means and said speed limit information before times acquired to acquire repeat speed limit information about the speed limit specified by road signs present in front of the vehicle comparing means for comparing the magnitude of the previous speed limit and newly acquired new speed limit to be new speed limit information to thus identify which is the speed limit information specified by the information, acquired the speed limit A display means for displaying information, and a display means for changing the timing of the display in accordance with the difference between the previous speed limit and the new speed limit, and a speed limit display method using a speed limit display device including: A speed limit information obtaining step of repeatedly obtaining the speed limit information based on the road sign by the speed information obtaining means; and the new speed limit information by the comparing means. And a display step of displaying the obtained speed limit information by the display means.At the display step, at least the new speed limit information is displayed. While the display of the previous speed limit information is maintained until it is displayed, the result of the comparison step is when the new speed limit is lower than the previous speed limit, and when the new speed limit is higher than the previous speed limit. The new speed limit information is displayed at an earlier timing .

  According to the present invention, even when the own vehicle passes through a position where the speed limit changes halfway while traveling, the start timing of the acceleration and deceleration of the own vehicle by the driver can be guided to an appropriate timing, and the safety can be improved. Can be improved.

FIG. 1 is a block diagram showing an electrical configuration of a vehicle speed limit display device according to an embodiment of the present invention. 5 is a flowchart of a speed limit display process in which the speed limit display device according to the embodiment of the present invention displays new speed limit information. FIG. 7 is a conceptual diagram illustrating timings of displaying a new speed limit and setting an upper limit speed according to a difference between a newly obtained speed limit and a previously obtained speed limit. FIG. 9 is a conceptual diagram illustrating a traveling state and a display state of a display device when the own vehicle passes a road sign when a new speed limit is lower than a previous speed limit. FIG. 4 is a conceptual diagram illustrating a traveling state and a display state of a display device when a host vehicle passes a road sign when a new speed limit is higher than a previous speed limit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the configuration of the vehicle speed limit display device according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an electrical configuration of a vehicle speed limit display device according to an embodiment of the present invention.

  In FIG. 1, reference numeral 1 indicates a vehicle speed limit display device according to an embodiment of the present invention. The vehicle speed limit display device 1 includes an ECU 2 (Electronic Control Unit), a camera 3, a display device 4, and a vehicle control device 5. The camera 3, the display device 4, and the vehicle control device 5 are electrically connected to the ECU 2.

  The camera 3 is installed toward the front of the host vehicle 10 (see the left column in FIGS. 4 and 5) on which the speed limit display device 1 is mounted, and captures image data of a road or the like in front of the host vehicle 10 taken. Output to the ECU 2 sequentially. As the camera 3, for example, a camera using a CMOS image sensor or a CCD image sensor as an image sensor is used. It should be noted that another in-vehicle camera such as an automatic sensing camera used for automatic braking, which is installed on the windshield of the vehicle 10, may be provided with the function of the camera 3 and also be used.

  The display device 4 is a device that displays various types of information output from the ECU 2. In this example, the display device 4 is visible as a combination meter in front of the driver's seat in the cabin of the host vehicle 10 so as to be visible by the driver. It is located near the speedometer.

The display device 4 of the present example includes three display screens 4a, 4b, and 4c (see the right columns in FIGS. 4 and 5), which are arranged side by side in the vehicle width direction. The display screen 4a on one side (left side) in the vehicle width direction is provided so as to be able to display at least a speed limit specified for the road on which the vehicle is currently traveling, and the display screen 4c on the other side (right side) in the vehicle width direction. Is provided so that the upper limit speed set by the upper limit speed setting unit 25 described later is displayed.
The display positions of the display screens 4a and 4b and the display screen 4c may be separated.

As shown in FIGS. 4 and 5, one-way traffic, entry prohibition, and the like are set for each road on the display screen 4 b at the center (between the display screens 4 a and 4 c) of the display device 4 of this example. When the traffic rule information is set, the traffic rule information is provided so as to be displayed.
In the right columns of FIGS. 4 and 5, the display screen 4b is omitted from illustration because the display content itself is out of the essence of the present invention. Further, if the display device 4 is provided within the field of view of the driver, other display means such as a head-up display (not shown) may be employed.

As shown in FIG. 1, the ECU 2 includes a sign recognition unit 21, a speed limit information acquisition unit 22, a speed limit comparison unit 23, a display control unit 24, and an upper limit speed setting unit 25.
These elements included in the ECU 2 include a CPU, various programs interpreted and executed on the CPU (including a basic control program such as an OS, and an application program activated on the OS to realize a specific function), and programs and various programs. And a computer having an internal memory such as a ROM or a RAM for storing the data.

  The sign recognition unit 21 specifies (displays) a speed limit specified for the road based on the contour, color, presence or absence of characters, etc. of the subject included in the image data in front of the vehicle 10 captured by the camera 3. The presence or absence of the sign 6 (hereinafter, referred to as “speed limit sign 6”) and the display content thereof are repeatedly recognized.

  In addition, as described above, the sign recognition unit 21 identifies a plurality of pieces of image data including the speed limit sign 6 by recognizing the speed limit sign 6 from a plurality of pieces of image data captured by the camera 3.

  Further, the ECU 2 (particularly, the display control unit 24 and the upper limit speed setting unit 25) restricts the vehicle 10 based on the position, size, and the like of the speed limit sign 6 for each of a plurality of image data including the speed limit sign 6. The point in time when the vehicle reaches the position of the speed marker 6 (see P1 in FIGS. 4 and 5) can be specified.

  Note that the ECU 2 is not limited to specifying the time point at which the host vehicle 10 has reached the position of the speed limit sign 6 based on the image data including the speed limit sign 6 as described above. The point at which the host vehicle 10 reaches the position of the speed limit sign 6 may be specified using another sensor such as a millimeter wave radar or an infrared laser (not shown) provided on the side.

  The speed limit information acquisition unit 22 performs a speed limit displayed on the speed limit display unit 6a of the speed limit sign 6 (see the left column in FIGS. 4 and 5), that is, the speed limit specified by the speed limit sign 6. The speed information is repeatedly acquired based on the area of the speed limit sign 6 recognized by the sign recognition unit 21 from the image data.

  The speed limit comparing unit 23 includes, among the speed limit information repeatedly acquired by the speed limit information acquiring unit 22, the speed limit specified by the previously acquired speed limit information (hereinafter, referred to as “previous speed limit”). A difference (large or small) from a speed limit (hereinafter, referred to as “new speed limit”) specified by the new speed limit information that is the newly obtained speed limit information is compared and determined, and the comparison result is displayed by the display control unit 24. And the upper limit speed setting unit 25.

  The display control unit 24 displays the speed limit information (speed limit) on the display device 4, and displays the speed limit information on the display screen 4 a based on the comparison result of the speed limit comparison unit 23. Control including timing. At the same time, in this example, the display control unit 24 controls the timing at which the upper limit speed set by the upper limit speed setting unit 25 is displayed on the display screen 4c.

  For example, when the display control unit 24 determines that it is necessary to change the display contents of the display screens 4a and 4c of the display device 4, the display control unit 24 displays the speed limit information to be changed in display on the display screens 4a and 4c of the display device 4. At a predetermined timing.

  The upper limit speed setting unit 25 sets the previous speed limit corresponding to the speed limit of the road on which the vehicle is currently traveling to the upper limit speed, and sets the comparison result of the speed limit comparison unit 23 (the difference between the previous speed limit and the new speed limit). Based on the setting of the new speed limit to the upper limit speed, control is performed including the timing of setting change.

  For example, when the speed limit comparing unit 23 determines that the own vehicle 10 needs to be decelerated, such as when the new speed limit is lower than the previous speed limit, the upper speed limit unit 25 sets at least the At a timing earlier than reaching the position of the speed sign 6, in other words, at least at a timing earlier than when the new speed limit is higher than the previous speed limit, a predetermined command to change the new speed limit to the upper speed limit is issued to the vehicle control. Output to the device 5.

  The vehicle control device 5 controls the output torque of the engine based on a command from the upper limit speed setting unit 25 so that the vehicle speed does not exceed the upper limit vehicle speed. For example, a vehicle speed sensor that detects the vehicle speed of the host vehicle 10, And a throttle actuator for controlling the throttle opening to adjust the amount of intake air to the engine.

  Thereby, when the vehicle control device 5 changes the setting of the new speed limit lower than the previous speed limit (current speed limit) to the upper limit speed, the vehicle control device 5 responds to the upper limit speed based on a command from the upper limit speed setting unit 25. Even if the driver does not perform the operation of returning the accelerator by reducing the throttle opening, the vehicle speed is automatically reduced promptly.

  The vehicle control device 5 may include a brake actuator or the like that controls a brake pressure in addition to the control of the engine output. When the host vehicle 10 exceeds the upper limit vehicle speed, the vehicle control device 5 automatically controls the vehicle at a predetermined timing. You may apply the brakes.

  Although not shown, the operation (upper limit vehicle speed setting function) of the upper limit speed setting unit 25 is enabled (on) or disabled (accessible) at a location where the driver can reach the vehicle 10 such as an instrument panel or a center console. An upper limit vehicle speed setting switch for turning off the vehicle is provided, and the upper limit vehicle speed setting switch is electrically connected to the ECU 2.

Next, processing performed by the vehicle speed limit display device 1 will be described with reference to FIGS. 2 and 3 to 5.
FIG. 2 is a flowchart of a speed limit display process in which the speed limit display device according to the embodiment of the present invention displays speed limit information. FIG. FIG. 3B is a conceptual diagram illustrating the display timing of the new speed limit and the timing of setting the new speed limit to the upper limit speed when the new speed limit is lower than the previous speed limit. FIG. 4 is a conceptual diagram exemplifying a display timing of a new speed limit and a timing of setting the new speed limit to an upper limit speed. FIG. FIG. 5 is a conceptual diagram exemplifying a running situation (left column in the figure) and a display state of the display device (right column in the figure) for each scene. FIG. Is a conceptual diagram illustrating a driving situation (in the figure the left column) and the display state of the display device 4 for each scene (in the figure right column) when the own vehicle passes the speed limit sign.

  4 and 5 are scenes in which the vehicle 10 has not yet recognized the presence of the speed limit sign 6 in front of the host vehicle 10, and both (b) of FIG. Is a scene at the time when the presence of the speed limit sign 6 is recognized (see P2 in FIGS. 4 and 5), and each (c) of FIG. (See P1 in FIGS. 4 and 5), and each of (d) in the same figure is a scene after the vehicle 10 has passed the position of the speed limit sign 6.

The speed limit display process is started when the ignition switch of the vehicle 10 is turned on and the power is turned on to the speed limit display device 1, and is repeatedly executed.
In this example, it is assumed that the upper limit vehicle speed setting switch is turned on.

However, here, as shown in each left column of FIGS. 4A and 5A, the vehicle 10 travels on a straight road with a speed limit of 50 km / h at a constant vehicle speed of 40 km / h. The speed limit display process described above is performed based on the flowchart shown in FIG. 2 while assuming a situation in which the vehicle passes a position where the speed limit changes halfway from 50 km / h (the position P1 of the speed limit sign 6). Will be explained.

  In the running state of the host vehicle 10 shown in each of the left columns of FIGS. 4A and 5A, as shown in FIGS. As the speed limit information (current speed limit information), 50 km / h has already been obtained, and as shown in the right columns of FIGS. 3A, 3B, 4A, and 5A. In addition, both 50 Km / h are displayed on the display screen 4a and the display screen 4c based on the previous speed limit information, and as shown in FIGS. It is set at 50 km / h corresponding to the speed limit of the middle road.

  As shown in each left column of FIGS. 4A and 5A, while the host vehicle 10 is traveling, recognition of the speed limit sign 6 by the sign recognition unit 21 and restriction by the speed limit information acquisition unit 22 are performed. The acquisition of the speed information is repeatedly executed.

  As shown in FIG. 2, the sign recognizing unit 21 continues the sign recognizing process as to whether or not the speed limit sign 6 is included in the plurality of image data repeatedly photographed by the camera 3 in step 1, as shown in FIG. 2. (Step 1: No).

  When the sign recognition unit 21 recognizes the presence of the speed limit sign 6 (step 1: Yes), the speed limit information acquisition unit 22 in the next step 2 performs the speed limit based on the image data including the recognized speed limit sign 6. Execute acquisition processing.

  The speed limit obtaining process in step 2 is performed until the speed limit information obtaining unit 22 obtains speed limit information regarding the speed limit from the area of the speed limit display unit 6a of the speed limit indicator 6 included in the image data (step 2: No).

  For example, as shown in FIG. 4, when the speed limit specified by the speed limit sign 6 (that is, displayed on the speed limit display section 6a of the speed limit sign 6) is 30 Km / h, FIG. ), The new speed limit information 30 Km / h is obtained by the speed limit information obtaining unit 22, while the speed limit specified by the speed limit indicator 6 is 80 Km / h as shown in FIG. 5. In FIG. 3B, the new speed limit information 80 Km / h is obtained by the speed limit information obtaining unit 22 as shown in FIG.

  When the new speed limit information is obtained in this way (Step 2: Yes), the speed limit comparison unit 23 performs the speed limit comparison process based on the new speed limit information and the previously obtained previous speed limit information in subsequent Steps 3 and 7. Is executed.

  In the speed limit comparison processes in steps 3 and 7, the speed limit comparison unit 23 uses the previous speed limit information and the new speed limit information among the speed limit information repeatedly acquired based on the speed limit indicator 6 as described above. The difference (large or small) of the specified speed limit is compared and determined.

  Then, when the comparison result indicates that the new speed limit (“current value” in FIGS. 2 and 3) is lower than the previous speed limit (“previous value” in FIGS. 2 and 3) (Step 3: Yes) At the time when the comparison result is output (see P2 in FIG. 4) (that is, immediately after the time when the comparison result is output), the display control unit 24 displays the new speed limit on the display screen 4a of the display device 4. At the same time (step 4), the new speed limit is displayed on the display screen 4c as the upper limit speed (step 5).

  For example, when the new speed limit is 30 km / h and the previous speed limit is 50 km / h, when the comparison judgment result of the speed limit comparing section 23 comes out, the speed limit shown in FIGS. As shown in the right column, the display control unit 24 displays the new speed limit 30 Km / h on the display screen 4a (step 4), and displays the new speed limit 30Km / h as the upper limit speed on the display screen 4c (step 4). 5).

Further, the upper limit speed setting unit 25 sets a new limit speed of 30 Km / h as the upper limit speed when the comparison determination result of the speed limit comparing unit 23 comes out (step 6).
That is, the upper limit speed setting unit 25 controls the vehicle control device 5 to automatically control the vehicle 10 so that the vehicle speed gradually reaches the new speed limit 30 Km / h toward the speed limit sign 6 without depressing the accelerator. Slow down.

  However, as shown in the right column of FIG. 4B, the speed limit display screen 4a of the display device 4 displays the speed limit display screen 4a until the vehicle 10 passes the position of the speed limit sign 6 (see FIG. (C), the previous speed limit of 50 km / h and the new speed limit of 30 km / h are tentatively displayed side by side without erasing the display of the previous speed limit of 50 km / h.

  Specifically, as shown in the figure, in order to make it easier for the driver to visually recognize the previous speed limit of 50 km / h, which is the speed limit of the road on which the vehicle is currently traveling, than the new speed limit of 30 km / h. By arranging the previous speed limit display 4a1 so as to be slightly shifted from each other so as to be located on the front side (front side) of the new speed limit display 4a2, the driver can display both speed limit displays 4a1 and 4a2. The previous speed limit is preferentially displayed while allowing visual confirmation.

  Here, in this example, when the camera 3 captures an image including the speed limit sign 6 and the sign recognition unit 21 recognizes the speed limit sign 6 for the first time from the image data, the host vehicle 10 moves approximately from the speed limit sign 6 This corresponds to a point in time when the vehicle travels at a distance of 30 m (see L = 30 m in FIGS. 4B and 5B). Therefore, the timing at which the comparison result by the speed limit comparing unit 23 is obtained is also the time when the host vehicle 10 travels at a position about 30 m before the speed limit sign 6.

  That is, the timing at which the comparison result by the speed limit comparing unit 23 is obtained depends on, for example, the resolution of the camera 3 and the recognition performance of the speed limit marker 6 by the sign recognition unit 21. Before reaching, the display control unit 24 can display the new speed limit on the display device 4 and the upper limit speed setting unit 25 can set the new speed limit to the upper limit speed.

  In this example, as described above, the timing at which the new speed limit is displayed or set as the upper limit speed is set to the time when the comparison result by the speed limit comparing unit 23 is obtained, so that the host vehicle 10 reaches the speed limit sign 6. Among the timings before the start, the earliest timing at which the new speed limit can be displayed or the upper limit speed can be set can be set.

  On the other hand, when the comparison result indicates that the new speed limit is higher than the previous speed limit (step 7: Yes), when the host vehicle 10 reaches the position of the speed limit sign 6 in the traveling direction (step 8: Yes). The display control unit 24 displays the new speed limit on the speed limit display screen 4a of the display device 4 (step 9), and displays the new speed limit on the display screen 4c as the upper limit speed (step 10).

  For example, when the new speed limit is 80 km / h and the previous speed limit is 50 km / h, as shown in the right columns of FIGS. 3B and 5B, the display control unit 24 sets the speed limit. Even if the comparison result of the comparison unit 23 is output, the new speed limit information 80 Km / h is not displayed on the speed limit display screen 4 a until the vehicle 10 reaches the position of the speed limit sign 6. The display is maintained (Step 8: No).

  Incidentally, the ECU 2 (the display control unit 24 and the upper limit speed setting unit 25) can specify the point in time when the vehicle 10 reaches the position of the speed limit sign 6 based on the captured image data of the camera 3.

  Then, as shown in the left column of FIG. 5C, the display control unit 24 only starts when the host vehicle 10 reaches the position of the speed limit sign 6 (Step 8: Yes), As shown in the right column of FIG. 5C, a new speed limit of 80 km / h is displayed on the display screen 4a (step 9), and the new speed limit of 80 km / h is displayed on the display screen 4c as an upper limit speed (step 9). 10).

Further, the upper limit speed setting unit 25 sets the new limit speed of 80 Km / h as the upper limit speed when the comparison result of the speed limit comparing unit 23 is obtained (step 11).
Thereby, the upper limit speed setting unit 25 accelerates the own vehicle 10 to the new limit speed of 80 km / h when the vehicle 10 travels at a position before reaching the position of the speed limit sign 6 (Step 8: No). Can be forcibly prevented.

  If the new speed limit is a comparison result indicating that the previous speed limit is the same as the previous speed limit (Step 3: No and Step 7: No), the speed limit comparing unit 23 sends the determination result to that effect to the ECU 2 (display control unit 24). And the upper limit speed setting unit 25), and the display control unit 24 maintains the display of the previous speed limit of 50 Km / h on each of the speed limit display screen 4a and the display screen 4c. The setting for setting the upper limit speed to the speed limit of 50 km / h is maintained (step 13).

  The processes in steps 1 to 13 described above are continued until the ignition switch is turned off. When the ignition switch is turned off, the speed limit display process ends.

  The speed limit display device 1 according to the present embodiment is a speed limit display device that displays speed limit information regarding a speed limit specified by a speed limit sign 6 present in front of the vehicle 10. A speed limit information acquisition unit 22 (speed limit information acquisition unit) that repeatedly acquires speed limit information based on the speed limit information, a speed limit comparison unit 23 (speed limit comparison unit) that compares the difference between the previous speed limit and the new speed limit, A display control unit 24 (display means) for displaying the acquired speed limit information on the display device 4, and an upper limit speed setting unit for setting a previous speed limit or a new speed limit corresponding to the speed limit of the road on which the vehicle is currently traveling to the upper limit speed. 25 (upper limit speed setting means) (see FIG. 1), the display controller 24 displays the previous speed limit information which is the previously obtained speed limit information, and the vehicle 10 travels. When passing through a position where the speed limit changes halfway, that is, when passing the speed limit sign 6, the display device 4 displays the new speed limit information, which is the speed limit information newly acquired from the previous speed limit information. The display contents of the screen 4a are changed (see steps 4 and 9 in FIG. 2, and FIGS. 3 (a) and 3 (b), and FIGS. 4 and 5), and are specified by the previous speed limit information and the new speed limit information, respectively. According to the difference between the speed limits (the new speed limit and the previous speed limit), the timing for displaying the new speed limit and setting the new speed limit to the upper limit speed is changed (FIG. 2). Steps 3-6, 7-11, and FIGS. 3 (a), 3 (b), 4 (b), 5 (c)).

  According to the above configuration, even when the vehicle 10 travels through a position where the speed limit changes halfway, the start timing of acceleration / deceleration of the vehicle 10 by the driver can be guided to an appropriate timing. Safety can be improved.

  As an aspect of the present invention, the timing at which the new speed limit information is displayed is set according to the relative position of the vehicle 10 before passing through the speed limit marker 6 with respect to the position of the speed limit marker 6. (See steps 3, 4, 7-9 in FIG. 2, FIGS. 3 (a), 3 (b), 4 (b), 5 (c)).

  According to the above configuration, for example, when the host vehicle 10 reaches the speed limit sign 6 or at a predetermined distance from the position of the speed limit sign 6 (see L in FIGS. 4B and 5B). By displaying the new speed limit information at the time when the vehicle is traveling only in front of the vehicle, the start timing of acceleration / deceleration of the vehicle 10 by the driver can be changed to a timing more suitable for driving under the new speed limit. I can guide you.

  As an embodiment of the present invention, a speed limit comparing unit 23 (speed limit comparing means) for comparing the new speed limit with the previous speed limit is provided, and the display control unit 24 determines whether the new speed limit (current value) is the previous speed limit. When the speed is lower than the previous speed (see step 3 in FIG. 2), the new speed limit (current value) is higher than the previous speed limit (previous value) (see step 7 in FIG. 2). The new speed limit information is displayed on the display screen 4a at an early timing (steps 3, 4, 7 to 9 in FIG. 2, FIGS. 3A, 3B, 4B, and 5C). )reference).

  As described above, when the new speed limit is lower than the previous speed limit, the speed limit specified by the new speed limit information is displayed at an earlier timing than when the new speed limit is higher than the previous speed limit. The driver can be prompted to start decelerating the vehicle 10 before the vehicle 10 reaches the position of the speed limit sign 6, and the new speed limit specified by the speed limit sign 6 immediately after passing the speed limit sign 6. It can run safely at the speed within.

  As an aspect of the present invention, when the new speed limit (current value) is lower than the previous speed limit (previous value) (see step 3 in FIG. 2), the display control unit 24 determines that the comparison result by the speed limit comparing unit 23 is The new speed limit information is displayed on the display screen 4a when the vehicle comes out (see steps 3 and 4 in FIG. 2, and FIGS. 3 (a) and 4 (b)).

  According to the above configuration, the time point at which the comparison result by the speed limit comparing unit 23 is obtained corresponds to the earliest timing at which the new speed limit information can be displayed. Therefore, if the new speed limit is lower than the previous speed limit, the new speed limit information is displayed immediately after the comparison result indicating that the speed limit is low, so that the speed limit of the traveling road is reduced. The time (distance) for decelerating the vehicle 10 in preparation for changing to the new speed limit lower than the previous speed limit (current speed limit) as the vehicle passes the speed limit sign 6 is set to It is possible to sufficiently secure the time until the vehicle 10 passes the speed limit sign 6.

  As an aspect of the present invention, the display control unit 24 displays both the new speed limit information and the previous speed limit information on the display screen 4a until the host vehicle 10 reaches the position of the speed limit sign 6 ( 3 (a) and 4 (b), and FIG. 4 (c).

  According to the above configuration, the display control unit 24 displays the new speed limit information on the display screen 4a until the vehicle 10 reaches the position of the speed limit sign 6 (4a2 in the right column of FIG. 4B). In the meantime, in preparation for the vehicle 10 to pass through the speed limit sign 6 and the speed limit to become lower than before, the driver must wait until the vehicle 10 reaches the position of the speed limit sign 6. , The deceleration of the vehicle 10 can be prompted. Further, the display control unit 24 displays the display screen 4a not only of the new speed limit information but also the previous speed limit information (speed limit of the road on which the vehicle is currently traveling) until the vehicle 10 reaches the position of the speed limit sign 6. (Refer to 4a1 in the right column of FIG. 4B), the driver can accurately grasp the previous speed limit information, and the speed limit changes from the previous speed limit to the new speed limit. The driver can intuitively and visually recognize that the host vehicle 10 is currently traveling at the position immediately before the vehicle is running.

  As an embodiment of the present invention, a speed limit comparing unit 23 for comparing the magnitude of the new speed limit with the previous speed limit is provided, and the display control unit 24 determines that the new speed limit (current value) is higher than the previous speed limit (previous value). If the vehicle speed is high (see step 7 in FIG. 2), the new speed limit information is displayed on the display screen 4a when the vehicle 10 reaches the position of the speed limit sign 6 (steps 8 and 9 in FIG. 2). 3 (b) and 5 (c)).

  According to the above configuration, when the new speed limit is higher than the previous speed limit, even if the host vehicle 10 recognizes the presence before the speed limit sign 6, the display control unit 24 determines that the host vehicle 10 has the speed limit sign. The new speed limit information is not displayed until the vehicle reaches the position No. 6, and the new speed limit information is displayed on the display screen 4a only when the vehicle reaches the position. Only when the new speed limit is changed, the start of acceleration of the vehicle 10 can be prompted.

  As an aspect of the present invention, a camera 3 (photographing means) for photographing the front of the vehicle 10 and a sign for recognizing the speed limit sign 6 from image data including the speed limit sign 6 photographed by the camera 3 And a recognition unit 21 (a sign recognition unit) (see FIG. 1).

  According to the above configuration, the speed limit information acquisition unit 22 can acquire speed limit information from image data captured by the camera 3 based on the speed limit sign 6 recognized by the sign recognition unit 21 (FIG. 2 steps 1 and 2). Thereby, the speed limit information obtaining unit 22 can obtain the speed limit information based on the speed limit specified by the speed limit sign 6 provided on the road on which the vehicle actually travels, and is changed by traffic volume, construction, and the like. Corresponding to the speed limit specified for a certain road, the speed limit information based on the current road sign information of the road on which the host vehicle 10 actually travels can be acquired more accurately.

The present invention is not limited to the configuration of the above-described embodiment, but can be formed in various embodiments.
For example, in the present invention, when the new speed limit information is lower than the previous speed limit information, the display change timing of the new speed limit information is as shown in steps 3 and 4 of the above-described speed limit display process (the flowchart of FIG. 2). The timing is not limited to the time when the comparison result by the speed limit comparing unit 22 is obtained, but may be any timing that is at least earlier than the time when the host vehicle reaches the position of the road sign.

The timing at which the new speed limit information is displayed is not limited to the difference (low or high) between the previous speed limit and the new speed limit, and may be changed according to the degree of these differences.
For example, it is presumed that the lower the new speed limit is than the previous speed limit (the larger the difference), the more often the distance required for the vehicle to decelerate before reaching the position of the road sign is required. Therefore, the new speed limit information may be displayed from the near side with respect to the road sign in accordance with the low degree (the magnitude of the difference).

  In the above-described speed limit display process (the flowchart of FIG. 2), the speed limit information acquiring unit 22 performs the speed limit based on the speed limit sign 6 recognized by the sign recognition unit 21 from the image data captured by the camera 3. The speed information is acquired (steps 1 and 2), and the speed limit comparing unit 23 performs the comparison processing of steps 3 and 7 based on the speed limit information acquired by the speed limit information acquiring unit 22, but the present invention is not limited to this. Not limited to the above, the sign recognition means may use a navigation system (a system that specifies the current position of the own vehicle using a GPS (Global Positioning System) or the like and provides various information related to the current position) on the road. A configuration for acquiring prescribed speed limit information may be adopted.

  In this case, the navigation system provides the ECU with various kinds of speed limit information for specifying the previous speed limit at the current position of the vehicle and the new speed limit obtained thereafter.

  In the present invention, the upper limit setting unit 25, the process of setting the new speed limit to the upper limit speed of the vehicle 10 by the upper limit setting unit 25 (the processes of steps 6 and 11 in FIG. 2), the display screen 4c, and the display The process of displaying the upper limit speed set on the screen 4c (the processes of steps 5 and 10 in FIG. 2) is not essential, and these configurations may be omitted.

  It should be noted that the road sign of the present invention is not limited to a road sign such as a pillar or a gate, which is installed so as to straddle a road side or a road.

1 ... Limited vehicle speed display 3 ... Camera (photographing means)
6. Speed limit sign (road sign)
10: own vehicle 21: sign recognition unit (sign recognition means)
22 ... speed limit information acquisition unit (speed limit information acquisition means)
23: Speed limit comparison section (comparison means)
24 display control unit (display means)
S2: Speed limit information acquisition process S4, S8: Display process

Claims (6)

A speed limit display device that displays speed limit information on a speed limit specified by a road sign present in front of the vehicle,
Speed limit information obtaining means for repeatedly obtaining speed limit information based on a road sign;
Display means for displaying the acquired the speed limit information,
Compare the magnitude of the previous speed limit specified by the previous speed limit information that is the previously obtained speed limit information with the new speed limit specified by the new speed limit information that is the newly obtained speed limit information Comparing means ,
The display means is adapted to change the timing for displaying on SL new speed limit information in accordance with the difference between the previous speed limit and the new speed limit,
Further, the display means maintains the display of the previous speed limit information at least until the new speed limit information is displayed, and when the new speed limit is lower than the previous speed limit, the new speed limit is set to the previous speed limit. The vehicle speed limit display device displays the new speed limit information at an earlier timing than when the speed is higher than the speed . When the new speed limit is lower than the previous speed limit, the display means displays the new speed limit information at an earlier timing as the difference between the previous speed limit and the new speed limit is larger.
The vehicle speed limit display device according to claim 1. When the new speed limit is lower than the previous speed limit, the display means displays the new speed limit information at the time when the comparison result by the comparing means comes out, while the new speed limit is the last time speed limit. The vehicle speed limit display device according to claim 1 or 2 , wherein the new speed limit information is displayed when the own vehicle reaches the position of the road sign when the vehicle speed is higher than the speed limit. 4. The vehicle speed limit display device according to claim 3 , wherein the display means displays both the new speed limit information and the previous speed limit information until the vehicle reaches the position of the road sign. The display means is arranged so as to be shifted from each other so that the display of the previous speed limit is located closer to the front side than the display of the new speed limit.
The vehicle speed limit display device according to claim 4. Identified by previous speed limit information and speed limit information obtaining means for obtaining repeat speed limit information about the speed limit is specified, a pre-time acquired in the speed limit information by road signs present in front of the vehicle comparing means for comparing the magnitude of the previous speed limit and newly acquired new speed limit thus identified in the new speed limit information which is the speed limit information, and displays the acquired the speed limit information A display means for changing the timing of the display in accordance with the difference between the previous speed limit and the new speed limit, and a speed limit display method performed using a speed limit display device including:
A speed limit information obtaining step of repeatedly obtaining the speed limit information based on the road sign by the speed information obtaining means;
A comparing step of comparing the magnitude of the new speed limit with the previous speed limit by the comparing means;
A display step of displaying the obtained speed limit information by the display means,
In the displaying step, the display of the previous speed limit information is maintained at least until the new speed limit information is displayed, and if the result of the comparing step is that the new speed limit is lower than the previous speed limit, the new speed limit is displayed. A vehicle speed limit display method, wherein the new speed limit information is displayed at an earlier timing than when the speed limit is higher than the previous speed limit.

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