JP6288205B1 - Vehicle speed limit detection device - Google Patents

Abstract

There is provided a vehicle speed limit detection device capable of detecting a speed limit more reliably by eliminating erroneous detection of the speed limit of the vehicle. A vehicle speed limit detecting device includes a camera, a speed limit detecting unit that detects information on a speed limit when the host vehicle is traveling from an image captured by the camera, and a lane that detects a lane width. The width detection unit 12, the first speed limit verification unit 20 that verifies whether the detected speed limit is correct based on the detected lane width, and the traveling speed of the surrounding vehicles existing around the host vehicle. A peripheral vehicle speed detection unit that detects information, a second speed limit verification unit 22 that verifies whether the detected speed limit is correct based on the detected traveling speed of the surrounding vehicle, and a first speed limit verification Display device 8 that displays information based on the speed limit verified by the unit 20 and / or the second speed limit verification unit 22. [Selection] Figure 1

Description

  The present invention relates to a vehicle speed limit detection device, and more particularly, to a vehicle speed limit detection device that recognizes a road sign of a speed limit existing in front of the host vehicle and verifies whether the detected speed limit is correct.

2. Description of the Related Art Conventionally, it has been proposed to capture the front of a vehicle with a camera and acquire information necessary for driving support or the like based on the captured image.
For example, Patent Document 1 discloses an in-vehicle device that extracts information such as a road sign from an image captured by an in-vehicle camera and displays the information on a display device such as a display. This in-vehicle device is applicable to roads corresponding to the image acquired by the imaging device even when the sign information corresponding to the vehicle position information acquired by GPS or the like is present in the road sign information stored in the information storage means for car navigation. If the sign can be extracted, the extracted road sign information is preferentially displayed on the display device.

JP 2007-183664 A

  However, in the on-vehicle apparatus as described above, the analysis accuracy of the image captured by the camera is not perfect at present. For this reason, for example, signs other than road signs and road signs may be misrecognized as road signs, and in particular, when an in-vehicle device displays a speed limit, an incorrect speed limit is displayed to the driver. It may be displayed.

  The present invention has been made in order to solve the above-described problems of the prior art, and is capable of detecting a speed limit more reliably by eliminating erroneous detection of the speed limit of the vehicle. An object is to provide a detection device.

  In order to achieve the above object, a speed limit detecting device for a vehicle according to the present invention includes a photographing unit configured to photograph the front of the host vehicle, and a limit when the host vehicle travels from an image photographed by the photographing unit. Speed limit detecting means configured to detect speed information, lane width detecting means configured to detect the lane width of the lane in which the host vehicle travels, and speed limit detected by the speed limit detecting means The first verification means configured to verify whether or not the vehicle is correct based on the lane width detected by the lane width detection means, and information related to the traveling speed of the surrounding vehicles existing around the host vehicle Whether or not the peripheral vehicle speed detection means and the speed limit detected by the speed limit detection means are correct is verified based on the information on the traveling speed of the peripheral vehicles detected by the peripheral vehicle speed detection means. And a second verification unit configured as described above, and a notification unit configured to notify information based on the speed limit verified by the first verification unit and / or the second verification unit. Yes.

According to the present invention configured as described above, the vehicle speed limit detection device captures an image in front of the host vehicle by the imaging unit, and detects information on the speed limit during travel of the host vehicle from the captured image. On the other hand, the lane width detection means detects the lane width of the lane in which the host vehicle is traveling. Here, the speed limit of the road is set according to the lane width, traffic conditions, roadside environment, etc. Therefore, in general, the speed limit is small on the road with a narrow lane width and the road with a wide lane width. Then, the speed limit is set large. Therefore, in the present invention, the first verification means verifies whether or not the speed limit detected from the image is correct based on the detected lane width.
The surrounding vehicle speed detection means detects information related to the traveling speed of the surrounding vehicles existing around the host vehicle. Here, the driver of the surrounding vehicle is traveling at a predetermined traveling speed in consideration of the speed limit of the traveling path and other traffic conditions, and therefore, between the speed limit and the traveling speed of the surrounding vehicle. Is considered to have a certain degree of correlation. Therefore, in the present invention, the second verification means verifies whether or not the speed limit detected from the image is correct based on the detected information on the traveling speed of the surrounding vehicle. Then, the notification means notifies information based on the speed limit verified by the first verification means and / or the second verification means.

  As described above, in the present invention, the first verification means verifies the correctness of the detected speed limit based on the lane width, and the second verification means relates the detected speed limit to the traveling speed of the surrounding vehicle. Since verification is performed based on the information, if the speed limit of the vehicle detected from the image captured by the imaging means is a false detection, it is possible to exclude the information from being used. Thus, it is possible to prevent erroneous display due to erroneous detection, and to detect the speed limit more reliably.

In the present invention, it is preferable that the notification means notifies the information based on the speed limit only when the first verification means determines that the speed limit is correct and the second verification means determines that the speed limit is correct. It is configured.
According to the present invention configured as described above, information based on the speed limit is notified only when the detected speed limit is verified to be correct by both the first verification means and the second verification means. An erroneous detection of the speed limit is more reliably prevented, and a more accurate speed limit is detected.

In the present invention, it is preferable that the second verification unit is configured not to perform verification based on information on the traveling speed of the surrounding vehicle when the number of detected surrounding vehicles is equal to or less than a predetermined number.
According to the present invention configured as above, the second verification means does not verify the speed limit when the number of detected surrounding vehicles is equal to or less than a predetermined number. When the number of surrounding vehicles existing around the host vehicle is small, there is a possibility that information relating to the traveling speed appropriate for verification of the speed limit may not be obtained. Therefore, in the present invention, when the number of detected surrounding vehicles is equal to or less than the predetermined number, the verification based on the information on the traveling speed of the surrounding vehicles is not performed, thereby preventing the inaccurate verification of the speed limit, It becomes possible to detect the speed limit.

In the present invention, it is preferable that the notifying unit limits the speed limit based on the result of the other verification of the first verification unit and the second verification unit when one of the first verification unit and the second verification unit does not perform verification. It is comprised so that the information based on may be alert | reported.
According to the present invention configured as described above, when one of the first verification unit and the second verification unit does not perform verification, information based on the speed limit is notified based on the other verification result. Therefore, even when either one of the first verification means and the second verification means cannot properly verify the speed limit, the speed limit is verified by the other verification means. By preventing erroneous display due to erroneous detection of speed, it becomes possible to detect the speed limit more reliably.

In the present invention, preferably, the verification means is configured to perform verification by the first verification means and / or the second verification means when the detected speed limit is different from the speed limit immediately before being verified as correct. Has been.
According to the present invention configured as described above, when a speed limit different from the speed limit immediately before being verified as correct is detected, there is a possibility that the detected speed limit is a false detection. Therefore, in the present invention, when the detected speed limit is different from the speed limit immediately before being verified as correct, verification based on the first verification means and / or the second verification means is performed. Therefore, since the verification is performed when the possibility of erroneous detection is relatively high, the verification is performed more efficiently.

In the present invention, preferably, the notification means is a display means for displaying the speed limit to the passenger of the host vehicle, and when the first verification means and / or the second verification means determines that the speed limit is incorrect, The display means is configured to continuously display the information on the displayed speed limit.
According to the present invention configured as described above, when the detected speed limit is not correct as a result of the verification by the first verification means and / or the second verification means, the detected speed limit is not displayed and the display means is displayed. Continues to display the speed limit currently displayed. Accordingly, an erroneous display that displays an incorrect speed limit is prevented, and frequent display changes of the display means are prevented, and a sense of discomfort that the passenger may feel is suppressed.

  According to the vehicle speed limit detection device of the present invention, it is possible to eliminate the erroneous detection of the vehicle speed limit and to detect the speed limit more reliably.

1 is a configuration block diagram of a vehicle speed limit detection device according to a first embodiment of the present invention. It is a figure which shows the allowable speed limit range with respect to the lane width of the speed limit detecting device for vehicles by 1st embodiment of this invention. It is a figure which shows the allowable running speed of the vehicle with respect to the speed limit of the speed limit detecting device for vehicles by 1st embodiment of this invention. It is a flowchart of the speed limit detection process of the speed limit detection apparatus for vehicles by 1st embodiment of this invention. It is a flowchart of the speed limit detection process of the speed limit detection apparatus for vehicles by 2nd embodiment of this invention. It is a flowchart of the speed limit detection process of the speed limit detection apparatus for vehicles by 2nd embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the second and subsequent embodiments, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof will be simplified or omitted.

[First Embodiment]

A vehicle speed limit detection device according to a first embodiment of the present invention will be described.
FIG. 1 is a block diagram showing a configuration of a speed limit detecting device 1 for a vehicle according to a first embodiment of the present invention. As shown in FIG. 1, the speed limit detection device 1 according to the present embodiment is a camera 2 that captures the front of the host vehicle, and a surrounding vehicle measuring unit that measures the running conditions of surrounding vehicles existing around the host vehicle. Radar 4, ECU 6 (Electronic Control Unit) to which image data taken by the camera 2 and information on the running conditions of surrounding vehicles measured by the radar 4 are input, and a display device 8 for displaying various information output from the ECU 6. And have.

  The camera 2 is installed in the host vehicle toward the front of the host vehicle on which the speed limit detection device 1 is mounted, and outputs captured image data to the ECU 6. As this camera 2, for example, a camera using a CMOS image sensor or a CCD image sensor as an image sensor is used.

  The radar 4 is a measuring device that measures the position and speed of an object, and is provided on both sides in the vehicle width direction before and after the host vehicle. The radar 4 transmits radio waves (transmission waves) toward the front, rear, left and right of the host vehicle, and receives reflected waves generated by reflection of the transmission waves by the object. In the present embodiment, the radar 4 determines the position between the own vehicle and the surrounding vehicle (for example, the inter-vehicle distance, the angular position with respect to the vehicle, etc.) and the relative speed of the surrounding vehicle with respect to the own vehicle based on the transmitted wave and the received wave. The measurement results are output to the ECU 6.

  The display device 8 is provided in the driver's field of view at the front of the passenger compartment of the host vehicle. As the display device 8, for example, a liquid crystal display or a head-up display is used.

  The ECU 6 recognizes a road sign of the speed limit when the host vehicle travels on the road from the image taken by the camera 2 and detects information on the speed limit Va, and the vehicle travels. A lane width detection unit 12 that detects a lane width W of a lane that is present, an allowable speed limit range acquisition unit 14 that acquires an allowable speed limit range set according to the lane width W, and an image and radar imaged by the camera 2 4 is set in advance according to the surrounding vehicle speed detection unit 16 that calculates the traveling speed Vc of the surrounding vehicle based on the measurement result of the traveling state of the surrounding vehicle input from 4, and the speed limit Va detected by the speed limit detection unit 10. Based on the lane width W, the allowable travel speed range acquisition unit 18 that acquires the allowable travel speed range of the travel speed Vc of the surrounding vehicles and the speed limit Va detected by the speed limit detection unit 10 are correct. A first speed limit verification unit 20 that verifies the speed limit, and a second speed limit verification unit 22 that verifies whether the speed limit Va detected by the speed limit detection unit 8 is correct based on the traveling speed Vc of the surrounding vehicle, Have

  These elements included in the ECU 6 include a CPU, various programs that are interpreted and executed on the CPU (including basic control programs such as an OS and application programs that are activated on the OS to realize specific functions), programs, and various types It is comprised by the computer provided with internal memory like ROM and RAM for memorize | storing these data.

  The speed limit detection unit 10 is configured to recognize a road sign of the speed limit Va from an image captured by the camera 2. Specifically, for example, a road sign of the speed limit Va is normally displayed with a number of the speed limit Va in a red circular mark, so the speed limit detection unit 10 combines the circular mark and the internal number. The image is configured to be recognized from images taken by the camera 2. Further, the speed limit detecting unit 10 is configured to detect information on the speed limit Va from the recognized road sign of the speed limit Va, that is, information on the number of the speed limit Va.

The lane width detection unit 12 recognizes two white lines on both sides of the travel path on which the vehicle travels from the image taken by the camera 2 and detects the distance between these two white lines as the lane width W. It is configured as follows. For example, when there is no white line on one side or both sides, the lane width detection unit 12 cannot detect the distance between the white lines, and therefore, it is determined that the lane width W is “not detected”.
Note that the lane width detection unit 10 may be configured to detect the lane width based on other information such as a guard rail, a median strip, and a road shoulder in addition to the white line.

The permissible speed limit range acquiring unit 14 is configured to acquire a permissible speed limit range set in advance according to the lane width W detected by the lane width detecting unit 12.
FIG. 2 is a diagram showing an allowable speed limit range with respect to the lane width W of the vehicle speed limit detecting device 1 according to the present embodiment. Here, the speed limit is determined in consideration of conditions such as the lane width, road structure, traffic conditions, roadside environment, etc. Generally, when the lane width is narrow, the speed limit is set small, and when the lane width is wide Is set large. Thus, the speed limit has a degree of correlation with the lane width. Therefore, in the present embodiment, referring to the relationship between the lane width and the speed limit, a range of the speed limit Va allowed for the detected lane width W is set in a table as shown in FIG. ing.

For example, if there is no white line on one side of the road or no white line on both sides of the road, the lane width detection unit 12 may not detect the lane width W and may determine “not detected”. . In such a case, the allowable speed limit range is set to the same range as the case where the lane width W is 2.75 to 2.99 m in the table of the present embodiment. In addition, when the detected lane width W is 2.49 m or less, it is assumed that the travel speed is not set so that the speed limit is set. Therefore, the allowable speed limit range is set in the table of this embodiment. It has not been.
As described above, the allowable speed limit range acquisition unit 14 is configured to acquire the allowable speed limit range corresponding to the detected lane width W from the table set as described above.

The surrounding vehicle speed detection unit 16 recognizes a surrounding vehicle traveling around the host vehicle from the image taken by the camera 2, and obtains information on the position and relative speed of the surrounding vehicle with respect to the host vehicle and information on the probability of image recognition. Configured to detect. Therefore, in this embodiment, the camera 2 also functions as a surrounding vehicle measurement unit. And the surrounding vehicle speed detection part 16 is comprised so that the traveling speed of a surrounding vehicle may be calculated from the relative speed of the surrounding vehicle with respect to the own vehicle, and the traveling speed of the own vehicle.
In addition, the surrounding vehicle speed detection unit 16 determines the position of the vehicle from the position between the own vehicle and the surrounding vehicle measured by the radar 4 (for example, the distance between the vehicles, the angular position with respect to the vehicle, etc.) The position and relative speed of the surrounding vehicle with respect to the vehicle, and information on the probability of the measurement result calculated from the intensity of the reflected wave of the radar 4, for example, are calculated.

When there are a plurality of surrounding vehicles in the image, or when there are a plurality of pieces of information on the driving situation about the surrounding vehicles input from the radar 4, the surrounding vehicle speed detection unit 16 determines the own vehicle for each surrounding vehicle. The position and relative speed of the surrounding vehicle with respect to the vehicle and the information on the reliability of the image recognition or the information on the accuracy of the measurement result are calculated. In this case, the surrounding vehicle speed detection unit 16 may calculate the traveling speed information for the plurality of surrounding vehicles, and then may employ an average value of the traveling speeds of the surrounding vehicles. The traveling speed of the surrounding vehicles may be calculated by performing weighting based on the certainty of recognition and the certainty of the measurement result.
In addition, the surrounding vehicle speed detection unit 16 is configured to detect information about a surrounding vehicle that is traveling in the same direction as the host vehicle at a certain speed or more, for example, when the surrounding vehicle is stopped, If the surrounding vehicle is an oncoming vehicle and traveling in the opposite direction, etc., it is obviously not appropriate to recognize it as a surrounding vehicle in this embodiment, so that information about the surrounding vehicle is not adopted. It is configured.

The peripheral vehicle speed detection unit 16 is configured based on the information on the accuracy of image recognition of the image captured by the camera 2 and the information on the reliability of the driving situation of the surrounding vehicle and the measurement result input from the radar 4. 2 is configured so that one of the peripheral vehicle speed detected from the image captured in 2 and the peripheral vehicle speed detected from the travel condition of the peripheral vehicle measured by the radar 4 is selected as the travel speed Vc of the peripheral vehicle. Has been.
The surrounding vehicle speed detection unit 16 detects and calculates both the surrounding vehicle speed detected from the image taken by the camera 2 and the surrounding vehicle speed detected from the traveling state of the surrounding vehicle measured by the radar 4. Not only the method of selecting one of the above, but only one of the detection methods may be employed.

The allowable traveling speed range acquisition unit 18 is configured to acquire an allowable traveling speed range of the traveling speeds of the surrounding vehicles.
FIG. 3 is a diagram illustrating the allowable traveling speed of the vehicle with respect to the speed limit Va of the vehicle speed limit detecting device 1 according to the first embodiment. As shown in FIG. 3, in this embodiment, the allowable traveling speed range of the traveling speed of the surrounding vehicle is set in the table according to the limiting speed Va detected by the limiting speed detecting unit 10, and the allowable traveling speed range is set. The acquisition unit 18 is configured to acquire an allowable travel speed range corresponding to the detected speed limit Va based on this table.

The first speed limit verifying unit 20 determines whether or not the speed limit Va detected by the speed limit detecting unit 10 is within the allowable speed limit range acquired by the allowable speed limit range acquiring unit 14. It is configured to verify whether or not the detected speed limit Va is correct based on the lane width W.
The second speed limit verifying unit 22 determines whether or not the traveling speed Vc of the surrounding vehicle is within the allowable travel speed range acquired by the allowable travel speed range acquisition unit 18, thereby detecting the detected speed limit Va. It is configured to verify whether or not is correct based on the traveling speed Vc of the surrounding vehicle.

The ECU 6 verifies the speed limit by the first verification means 20 and the second verification means 22 when the speed limit Va detected by the speed limit detection unit 10 is different from the speed limit immediately before being verified as correct. It is configured.
The ECU 6 determines that the detected speed limit Va is correct only when the first verification means 20 determines that the speed limit Va is correct and the second verification means 22 determines that the speed limit Va is correct. Thus, the display device 8 is configured to perform display.

Next, speed limit detection / verification processing performed by the speed limit detection device 1 will be described.
FIG. 4 is a flowchart of the speed limit detecting process of the speed limit detecting device 1 according to the present embodiment. This speed limit detection process is started and executed repeatedly when the ignition of the vehicle is turned on and power is turned on to speed limit detection device 1.

As shown in FIG. 4, when the speed limit detection process is started, the camera 2 captures the front of the vehicle and outputs the captured image data to the ECU 6 (step S1).
Subsequently, the speed limit detection unit 10 recognizes the speed limit road sign included in the image data captured by the camera 2 and detects information on the speed limit Va. The ECU 6 determines whether or not the speed limit Va is detected (step S2), and if it is detected, proceeds to the next step. If it is determined in step S2 that the speed limit Va has not been detected, the process returns to step S1 and the camera 2 takes a picture in front of the vehicle.

When the speed limit Va is detected in step S2, the ECU 6 determines whether or not the detected speed limit Va is different from the speed limit immediately before it is determined to be correct. More specifically, in the present embodiment, the ECU 6 determines whether or not the detected speed limit Va is different from the speed limit Vb currently displayed on the display device 8 (step S3). When the speed limit Vb currently displayed on the display device 8 is different from the detected speed limit Va, the possibility that the speed limit Va is detected is relatively higher than when both are the same. Therefore, in the present embodiment, when both are different, the verification process of the speed limit Va by the first verification unit 20 and the second verification unit 22 is performed.
On the other hand, when both are the same, the verification process of the speed limit Va by the first verification unit 20 and the second verification unit 22 is not performed, and the process returns to step S1 and the front of the vehicle is captured by the camera 2. As a result, the speed limit Vb currently displayed on the display device 8 is continuously displayed as it is.

  In step S3, when the detected speed limit Va is different from the speed limit Vb currently displayed on the display device 8, the lane width detection unit 12 detects white lines existing on both sides of the vehicle from the image captured in step S1. Recognize and detect the distance between the two white lines as the lane width W (step S4). Next, the ECU 6 determines whether or not the detected lane width W is 2.49 m or less (step S5). In the present embodiment, when the lane width W is equal to or less than 2.49 m, the permitted speed limit range is not set, and thus the verification based on the lane width W is not performed, and the speed limit Va detected by the display device 6 Is not displayed, and the display of the speed limit Vb currently displayed on the display device 6 is erased (step S13).

  When the lane width W is larger than 2.49 m in step S5, the allowable speed limit range acquiring unit 14 acquires the allowable speed limit range corresponding to the lane width W detected from the preset table (step S6). Next, the first speed limit verifying unit 20 compares the speed limit Va detected by the speed limit detecting unit 10 with the allowable speed limit range acquired by the allowable speed limit range acquiring unit 14, and the speed limit Va. Is determined to be within the allowable speed limit range (step S7). If the speed limit Va is within the allowable speed limit range, the ECU 6 determines that the detected speed limit Va is correct and proceeds to step S8, where the second speed limit verification unit 22 determines the travel speed Vc of the surrounding vehicle. The verification process of the speed limit Va based on is started.

  On the other hand, if the speed limit Va is outside the allowable speed limit range in step S7, the ECU 6 determines that the detected speed limit Va is a false detection and does not output a display signal to the display device 8. As a result, the display device 8 does not display the speed limit Va (step S12), and the currently displayed speed limit is continuously displayed.

  In step S <b> 8, the surrounding vehicle speed detection unit 16 selects either the traveling speed of the surrounding vehicle detected from the image captured by the camera 2 captured in step S <b> 1 or the traveling speed of the surrounding vehicle detected from the information input from the radar 4. By selecting one of them, the traveling speed Vc of the surrounding vehicle is detected (step S8).

Next, the allowable travel speed range acquisition unit 18 acquires the allowable travel speed range of the vehicle corresponding to the speed limit Va detected from a preset table (step S9).
Then, the second speed limit verification unit 22 determines whether or not the detected travel speed Vc of the surrounding vehicle is within the allowable travel speed range acquired in step S9 (step S10).
When the detected traveling speed Vc of the surrounding vehicle is within the allowable traveling speed range (YES in step S10), the second speed limit verifying unit 22 determines that the detected speed limit Va is correct, and the ECU 6 displays A display signal of the speed limit Va is output to the device 8. The display device 8 updates / changes the information on the displayed speed limit, and displays the detected speed limit Va (step S11).

  On the other hand, if the detected travel speed Vc of the surrounding vehicle is not within the allowable travel speed range in step S10 (NO in step S10), the second speed limit verification unit 22 determines that the detected speed limit Va is not correct. To do. The ECU 6 does not output a display signal to the display device 8. As a result, the display device 8 does not display the detected speed limit Va and continues displaying the currently displayed speed limit (step S12).

According to the speed limit detection device 1 according to the present embodiment as described above, the following effects can be obtained.
The speed limit detection device 1 includes a speed limit detection unit 10, a lane width detection unit 12, an allowable speed limit range acquisition unit 14, and a first speed limit verification unit 20, and the speed limit detection unit 10 Information on the speed limit when the vehicle travels is detected from the image captured by the camera 2, and the first speed limit verification unit 20 detects the limit detected based on the lane width W detected by the lane width detection unit 12. Since it is verified whether or not the speed Va is correct, when the vehicle speed limit Va detected from the image taken by the camera 2 is erroneously detected, the information can be prevented from being displayed on the display device 8. . Therefore, it is possible to eliminate the erroneously detected information on the speed limit and perform a more reliable speed limit detection, and to display a more reliable speed limit on the display device 8.

  When the allowable speed limit range acquisition unit 14 acquires the allowable speed limit range according to the lane width W, and the first speed limit verification unit 20 detects that the detected speed limit Va is within the allowable speed limit range, the speed limit It is determined that Va is correct. Therefore, accurate speed limit detection can be performed with a simple verification method.

  The speed limit detection device 1 includes a speed limit detection unit 10, a surrounding vehicle speed detection unit 16, an allowable travel speed range acquisition unit 18, and a second speed limit verification unit 22. The information on the speed limit Va when the host vehicle is traveling is detected from the image taken by the camera 2, and the second speed limit verification unit 22 detects the travel speed Vc of the surrounding vehicle detected by the surrounding vehicle speed detection unit 16. Based on this, it is verified whether or not the detected speed limit Va is correct. Therefore, if the speed limit Va detected from the image taken by the camera 2 is erroneously detected, the information is displayed on the display device 8. You can hide it. Therefore, it is possible to eliminate the erroneously detected information on the speed limit Va and perform a more reliable speed limit detection, and to display a more reliable speed limit on the display device 8.

  The permissible travel speed range acquisition unit 18 acquires the permissible travel speed range of the vehicle corresponding to the speed limit Va detected by the speed limit detection unit 10, and the second speed limit verification unit 22 determines that the travel speed Vc of the surrounding vehicle is Since it is verified whether or not the detected speed limit Va is correct by determining whether or not it is within the acquired allowable travel speed range, the speed limit Va can be verified by a simple verification method. .

  The display device 8 displays information based on the speed limit Va only when the first speed limit verification unit 20 determines that the speed limit Va is correct and the second speed limit verification unit 22 determines that the speed limit Va is correct. Therefore, by using both of the two types of verification methods, erroneous detection of the speed limit can be prevented more reliably, and the speed limit can be detected more accurately.

  When the detected speed limit Va is different from the speed limit displayed on the display device 8, the first speed limit verification unit 20 and the second speed limit verification unit 22 set the lane width W and the traveling speed Vc of the surrounding vehicle. Based on verification. In other words, the first speed limit verification unit 20 and the second speed limit verification unit 22 are different from the speed limit immediately before verified as correct by the first speed limit verification unit 20 and the second speed limit verification unit 22. Verification based on the width W and the traveling speed Vc of surrounding vehicles is performed. Here, when the detected speed limit Va is different from the speed limit displayed on the display device 8, it is conceivable that the detected speed limit Va is a false detection. In the present embodiment, since the first speed limit verification unit 20 and the second speed limit verification unit 22 perform verification when there is a possibility of erroneous detection, the verification can be performed more efficiently.

  The speed limit detection device 1 does not display the speed limit Va on the display device 8 when it is determined that the detected speed limit Va is not correct. As a result, the speed limit currently displayed is continuously displayed on the display device 8. Accordingly, it is possible to prevent an erroneous display that displays an incorrect speed limit, and to prevent frequent and unnecessary display changes of the display device 8, which may cause a sense of discomfort that may be felt by the occupant. Confusion can be suppressed.

[Second Embodiment]
Next, a vehicle speed limit detecting device according to a second embodiment of the present invention will be described.
In the vehicle speed limit detection device 1 according to the second embodiment of the present invention, unlike the first embodiment, when the lane width W is not detected by the lane width detection unit 12, the allowable speed limit range is not set. . The first speed limit verifying unit 20 is configured not to verify the speed limit Va based on the lane width W when the lane width W is not detected by the lane width detecting unit 12.

Further, the second speed limit verification unit 22 does not verify the speed limit Va based on the travel speed Vc of the surrounding vehicle when the number of the surrounding vehicles detected by the camera 2 and the radar is 1 or less. It is configured.
The ECU 6 displays the speed limit Va on the display device 8 when one of the first speed limit verification unit 20 and the second speed limit verification unit 22 determines that the detected speed limit Va is correct. Therefore, the display device 8 is configured to output a display signal.

5A and 5B are flowcharts of the speed limit detection process of the vehicle speed limit detecting device 1 according to the second embodiment of the present invention.
Steps S21 to S23 are the same as steps S1 to S3 in the flowchart in the first embodiment, and thus the description thereof is omitted.

  When the speed limit Va is detected and the speed limit Va is different from the speed limit currently displayed on the display device 8, the ECU 6 determines whether the lane width detection unit 12 has detected the lane width W (step). S24). When the lane width W is not detected, in this embodiment, the allowable speed limit range is not set, and the ECU 6 does not verify the speed limit Va by the first speed limit verification unit 20 and proceeds to step S28. .

On the other hand, when the lane width W is detected in step S24, the first speed limit verifying unit 20 determines whether the detected lane width W is 2.49 m or less, as in the first embodiment. It is determined whether or not (step S25). When the lane width W is 2.49 m or less, the allowable speed limit range is not set. Therefore, in the present embodiment, the first speed limit verifying unit 20 does not perform verification based on the lane width W, and step S28. Proceed to
If the detected lane width W is greater than 2.49 m, the allowable speed limit range acquiring unit 18 acquires an allowable speed limit range corresponding to the detected lane width W (step S26), and the first speed limit is determined. The verification unit 20 verifies the speed limit Va based on the lane width W by determining whether or not the detected speed limit Va is within the allowable speed limit range (step S27).

  In step S27, when the detected speed limit Va is within the allowable speed limit range, the ECU 6 determines that the detected speed limit Va is correct, and outputs a display signal to the display device 8. The display device 8 Then, the speed limit Va is displayed (step S32).

  If the detected speed limit Va is not within the allowable speed limit range (NO in step S27), the ECU 6 determines the number of surrounding vehicles detected from the image captured by the camera 2 and the number of surrounding vehicles detected by the radar 4. It is determined whether or not there is a plurality (step S28). In the present embodiment, when both the number of surrounding vehicles detected from the image captured by the camera 2 and the number of surrounding vehicles detected by the radar 4 are 1 or less, the ECU 6 performs the second speed limit verification. The unit 22 determines that the traveling speed of the surrounding vehicle sufficient to verify the speed limit Va cannot be obtained, and does not verify the speed limiting Va based on the traveling speed of the surrounding vehicle. Is not displayed (step S33).

  On the other hand, if any one of the number of surrounding vehicles detected from the image captured by the camera 2 and the number of surrounding vehicles detected by the radar 4 is plural (more than 1) (YES in step S28), the ECU 6 Determines that the information on the traveling speed of the surrounding vehicle necessary for verification of the speed limit Va based on the traveling speed of the surrounding vehicle is obtained, and the speed limit Va based on the traveling speed of the surrounding vehicle by the second speed limiting unit 22 is determined. Start verification.

  The surrounding vehicle speed detection unit 16 uses information on the information detected by a plurality of surrounding vehicles among the information on the surrounding vehicles detected from the image captured by the camera 2 and the information on the surrounding vehicles detected by the radar 4. The average value of the travel speeds is calculated as the travel speed Vc of the surrounding vehicles (step S29). When the number of surrounding vehicles detected from the image captured by the camera 2 and the number of surrounding vehicles detected by the radar 4 are both plural, as in the first embodiment, One of the traveling speeds is selected based on the information of the certainty.

  The allowable travel speed range acquisition unit 18 acquires an allowable travel speed range corresponding to the travel speed Vc of the surrounding vehicle from a preset table (step S30). The second speed limit verification unit 22 determines whether or not the travel speed Vc of the surrounding vehicle is within the allowable travel speed range (step S31), and if it is within the allowable travel speed range, the ECU 6 detects the detected speed limit. It is determined that Va is correct, a display signal is output to the display device 8, and the display device 8 displays the speed limit Va (step S32). If the traveling speed Vc of the surrounding vehicle is not within the allowable traveling speed range (NO in step S31), the ECU 6 determines that the detected speed limit Va is not correct and does not output a display signal to the display device 8. As a result, the detected speed limit Va is not displayed on the display device 8, and the currently displayed speed limit is continuously displayed (step S33).

According to the second embodiment as described above, the following effects can be obtained in addition to the same effects as the first embodiment.
When the lane width detection unit 12 does not detect the lane width W, the first speed limit verification unit 20 does not verify the speed limit Va based on the lane width W, and the second speed limit verification unit 22 Verification is performed based on the speed, and the ECU 6 determines whether to display the speed limit Va on the display device 8 based on the result. In the present embodiment, the speed limit detection device 1 includes both the first speed limit verification unit 20 and the second speed limit verification unit 22, and thus the first speed limit verification unit 20 does not perform verification properly. If there is a possibility, the second speed limit verifying unit 22 can verify the speed limit while avoiding inappropriate verification, thereby preventing erroneous display due to erroneous detection of the speed limit. Thus, the speed limit can be detected more reliably.

  When the number of detected surrounding vehicles is 1 or less, the second speed limit verifying unit 22 does not perform verification based on the traveling speed of the surrounding vehicles. When the number of surrounding vehicles existing around the host vehicle is small, there is a possibility that data of a traveling speed appropriate for verification of the speed limit cannot be obtained. Therefore, in the present embodiment, when the number of detected surrounding vehicles is 1 or less, the verification based on the traveling speed of the surrounding vehicles is not performed, thereby avoiding inaccurate verification of the speed limit, The speed limit can be detected.

  The present invention is not limited to the embodiment described above, and may be, for example, as follows.

In the above-described embodiment, the second speed limit verification unit 22 determines whether or not the travel speed Vc of the surrounding vehicle is within the allowable travel speed range set according to the detected speed limit Va. Although the speed limit Va has been verified, the second speed limit verification unit 22 is not limited to this. For example, the difference between the speed limit Va detected by the speed limit detection unit 10 and the surrounding vehicle speed Vc is predetermined. It may be configured to verify whether or not the detected speed limit Va is correct by determining whether or not it is within the range. In this case, the second speed limit verification unit 22 detects the detected speed limit when the absolute value of the difference between the detected speed limit Va and the surrounding vehicle speed Vc is equal to or less than a predetermined value (for example, 20 km / h). It may be configured to determine that the speed va is correct.
Further, the second speed limit verification unit 22 detects the limit detected by determining whether or not the difference between the speed limit Va detected by the speed limit detection unit 10 and the surrounding vehicle speed Vc is within a predetermined range. When it is configured to verify whether or not the speed Va is correct, the predetermined range may be configured to change according to the detected speed limit Va. For example, the predetermined range may be set wider as the detected speed limit Va is larger.

  In the above-described embodiment, the surrounding vehicle speed detection unit 16 detects the traveling speed Vc of the surrounding vehicle, and the second speed limit verifying unit 22 verifies the speed limit Va based on the traveling speed Vc of the surrounding vehicle. For example, the surrounding vehicle speed detection unit 16 detects the relative speed between the surrounding vehicle and the host vehicle, and the second speed limit verification unit 22 also verifies the speed limit Va based on the relative speed. May be. In short, in the present invention, the peripheral vehicle speed detecting means may be any means as long as it detects information related to the traveling speed of the surrounding vehicle, including the relative speed of the surrounding vehicle, and the second verification means is the relative vehicle relative speed. What is necessary is just to verify the speed limit based on the information about the traveling speed including the speed.

In the second embodiment described above, after the verification based on the lane width W by the first speed limit verification unit 20, the verification based on the traveling speed Vc of the surrounding vehicle by the second speed limit verification unit 22 is performed. Instead, for example, the verification may be performed in the reverse order, that is, the verification based on the traveling speed Vc of the surrounding vehicle is performed first, and then the verification based on the lane width W may be performed.
In this case, the ECU 6 determines whether or not the number of surrounding vehicles detected is plural, and if the number of surrounding vehicles is 1 or less, the second speed limit verification unit 22 determines the traveling speed Vc of the surrounding vehicles. The first speed limit verification unit 20 may be configured to start verification based on the lane width W without performing verification based on.
Further, in the above case, if the detected speed limit is not determined to be correct as a result of the verification based on the traveling speed Vc of the surrounding vehicle, the verification based on the lane width W is performed. When the lane width W is 2.49 or less, the permitted speed limit range is not set, so that the detected speed limit is not displayed on the display device 8 and the currently displayed speed limit is erased. You may control.

  In the second embodiment described above, when the number of detected surrounding vehicles is 1 or less, the limit speed Va based on the traveling speed Vc of the surrounding vehicle is not verified. Is not limited to the case where the number of detected surrounding vehicles is 1 or less. For example, when the number of detected surrounding vehicles is equal to or less than a predetermined number, such as 2 or less, 3 or less, The speed limit based may not be verified.

  In the above-described embodiment, the notification means is a display means (display device 8) that displays the speed limit of the traveling path on a display or the like. However, the display means is not limited to this, and the display means displays information other than the speed limit. For example, the traveling speed of the host vehicle is monitored based on the detected and verified speed limit, and when the traveling speed of the host vehicle exceeds the speed limit, the display indicates that the speed limit is exceeded. May be displayed. Further, the notification means is not limited to displaying the right side on the display or the like, but any means for notifying the occupant based on the speed limit detected and verified, such as a means for emitting a warning sound or a voice, is used. Can do.

  In the above-described embodiment, the camera 2 is used as the photographing unit. However, the present invention is not limited thereto, and the photographing unit may be, for example, a video camera that photographs a moving image. In that case, it is only necessary to continuously shoot moving images with a video camera and extract necessary images from the image data.

1 Speed limit detection device 2 Camera (photographing means)
4 Radar 6 ECU
8 Display device (notification means, display means)
10 Speed limit detection unit (Speed limit detection means)
12 Lane width detection unit (lane width detection means)
14 Permitted speed limit range acquisition unit 16 Peripheral vehicle speed detection unit (peripheral vehicle speed detection means)
18 Allowable travel speed range acquisition unit 20 First speed limit verification unit (first verification means)
22 Second speed limit verification unit (second verification means)

Claims (6)

Photographing means configured to photograph the front of the host vehicle;
Speed limit detection means configured to detect information on speed limit during travel of the host vehicle from an image captured by the image capturing means;
Lane width detection means configured to detect the lane width of the lane in which the host vehicle travels;
First verification means configured to verify whether the speed limit detected by the speed limit detection means is correct based on the lane width detected by the lane width detection means;
Surrounding vehicle speed detection means for detecting information related to the traveling speed of surrounding vehicles existing around the host vehicle;
A second unit configured to verify whether or not the speed limit detected by the speed limit detecting unit is correct based on information on the traveling speed of the surrounding vehicle detected by the surrounding vehicle speed detecting unit. Verification means;
A notification means configured to notify information based on the speed limit verified by the first verification means and / or the second verification means,
A vehicle speed limit detecting device. The notification means is configured to notify information based on the speed limit only when the first verification means determines that the speed limit is correct and the second verification means determines that the speed limit is correct. Being
The vehicle speed limit detecting device according to claim 1. The second verification means is configured not to perform verification based on information on the traveling speed of the surrounding vehicle when the number of the detected surrounding vehicles is equal to or less than a predetermined number.
The vehicle speed limit detecting device according to claim 1 or 2. When one of the first verification unit and the second verification unit does not perform verification, the notification unit sets the speed limit based on the other verification result of the first verification unit and the second verification unit. Configured to broadcast information based on,
The vehicle speed limit detecting device according to any one of claims 1 to 3. The verification means is configured to perform verification by the first verification means and / or the second verification means when the detected speed limit is different from the speed limit immediately before being verified as correct. ,
The vehicle speed limit detection device according to any one of claims 1 to 4. The informing means is a display means for displaying a speed limit to an occupant of the host vehicle,
When the first verification unit and / or the second verification unit determines that the speed limit is not correct, the display unit is configured to continuously display information on the displayed speed limit. ing,
The vehicle speed limit detecting device according to any one of claims 1 to 5.

Images