JP2008262467A - Driving support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To clearly image both a traffic light which emits own light and a traffic sign which does not emit own light so as to be recognizable. <P>SOLUTION: When imaging a traffic light 19 or a traffic sign 20 by an external camera 13 at a timing determined based on map information containing a position of an intersection and the presence/absence of the traffic light 19 at the intersection and an own vehicle position of the map, a fixed exposure quantity is set when the imaging object is the traffic light 19 which emits light by itself. Therefore, the color of a light emitting part of the traffic light 19 can be surely recognized both in the night and in the daytime. When the imaging object is the traffic sign 20 which does not own light, a variable exposure quantity is set according to the brightness of the outside world. Therefore, the kind of the traffic sign 20 which does not emit light by itself can be surely recognized. According to this, recognition of the color of the light emitting part of the traffic light 19 or recognition of the shape or pattern of the traffic sign 20 can be prevented from being difficult due to excessively large exposure quantity or excessively small exposure quantity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a driving support device that recognizes a traffic light and a traffic sign based on an image captured by an imaging unit mounted on a vehicle.

Install a color camera on the vehicle to shoot traffic lights and traffic signs. If the color of the light-emitting part where the traffic light is lit is red, it will be judged as “stop”, if it is yellow, it will be “caution”, and if it is blue, it will be judged as “advance”. To the driver to assist driving, and to take a traffic sign with the color camera and compare the shape of the captured traffic sign with the shape described in the memory. It is known from Japanese Patent Application Laid-Open Publication No. 2003-259259 that a traffic sign indicating “no entry” if it is circular and notifying the driver of the information and providing driving assistance.
Japanese Patent Laid-Open No. 11-306498

  By the way, since the exposure time of the color camera is set uniformly in the one described in Patent Document 1, if the exposure time is set so that a traffic sign can be clearly captured in the daytime, the exposure time is insufficient at night. The type of traffic sign may not be recognized. In addition, if the exposure time is set to be long so that traffic signs can be clearly imaged at night, the color of the particularly important red signal may fly out and be mistakenly recognized as a yellow signal when recognizing the traffic light. It was.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to make it possible to clearly recognize and reliably recognize both a traffic light that emits light and a traffic sign that does not emit light.

  In order to achieve the above object, according to the first aspect of the present invention, in the driving assistance device for recognizing a traffic light and a traffic sign based on an image captured by an imaging means mounted on a vehicle, Map information storage means for storing map information including the presence or absence of traffic lights at intersections, vehicle position specifying means for specifying the vehicle position, map information stored in the map information storage means and specified by the vehicle position specifying means An imaging means for imaging the traffic light or the traffic sign at a timing determined based on the position of the subject vehicle, and an exposure amount of the imaging means is controlled according to whether the imaging target is the traffic light or the traffic sign And a driving support device characterized by comprising a control means.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the control unit sets a fixed exposure amount when the imaging target is the traffic light, and the imaging target is In the case of the traffic sign, a driving support device is proposed in which a variable exposure amount according to the environment is set.

  The navigation device 11 of the embodiment corresponds to the vehicle position specifying means of the present invention, the external camera 13 of the embodiment corresponds to the imaging means of the invention, and the exposure time setting unit M3 of the embodiment This corresponds to the control means of the invention.

  According to the configuration of the first aspect, the traffic signal or the traffic sign is imaged by the imaging means at a timing determined based on the map information including the position of the intersection and the presence / absence of the traffic signal at the intersection and the own vehicle position on the map. In this case, since the exposure amount of the imaging means is controlled depending on whether the imaging target is a traffic light that emits light or a traffic sign that does not emit light, the exposure amount is too large and the color of the light emitting part of the traffic light is recognized. It can be prevented that it becomes difficult or the amount of exposure is too small to make it difficult to recognize the shape and pattern of a traffic sign.

  According to the second aspect of the present invention, when the object to be imaged is a traffic light that emits light by itself, a fixed exposure amount is set, so that the color of the light emitting portion of the traffic light is ensured even at night or in the daytime. Can be recognized. In addition, when the object to be imaged is a traffic sign, a variable exposure amount is set according to the environment, so a traffic sign that does not emit light by itself can be set by setting a small exposure amount during the day and a large exposure amount at night. Even so, the type can be reliably recognized.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 and 2 relate to an embodiment of the present invention. FIG. 1 is a block diagram of a driving support apparatus, and FIG. 2 is a flowchart of setting an exposure time of an external camera.

  As shown in FIG. 1, the driving support device mounted on the vehicle includes a known navigation device 11, map information storage means 12 for storing map information including the presence or absence of a traffic light 19 at an intersection, and an image of the front of the vehicle. An external camera 13 comprising a color camera to be imaged, shape data storage means 14 for storing the shape and color of the traffic sign 20, an illuminance sensor 15 for detecting the brightness of the external environment, vehicle speed, yaw rate, operation of the brake pedal, steering A vehicle state detector 16 comprising a plurality of sensors for detecting the vehicle state such as corners, a braking device 17 for automatically operating wheel brakes, and a warning to the driver with a buzzer, chime, voice, etc. And an alarm device 18, which are connected to the electronic control unit U.

  The electronic control unit U includes an intersection position determination unit M1, a traffic light presence / absence determination unit M2, an exposure time setting unit M3, a traffic light state determination unit M4, a traffic sign type determination unit M5, and a travel control unit M6. The navigation device 11 and the map information storage unit 12 are connected to the intersection position determination unit M1, the external camera 13 and the illuminance sensor 15 are connected to the exposure time setting unit M3, and the external camera 13 is connected to the traffic light state determination unit M4. Then, the external camera 13 and the shape data storage means 14 are connected to the traffic sign type determination unit M5, and the host vehicle state detection unit 16, the braking device 17 and the alarm device 18 are connected to the travel control unit M6.

  The intersection position determination unit M1 of the electronic control unit U determines that the own vehicle has approached the intersection from the own vehicle position obtained from the navigation device 11 and the position of the intersection obtained from the map information storage means 12. The traffic signal presence / absence determination unit M2 determines the presence / absence of the traffic signal 19 at the intersection approaching the host vehicle from the data stored in the map information storage unit 12. When the traffic light presence / absence determination unit M2 determines that the traffic light 19 is present, the exposure time setting unit M3 is independent of the brightness of the external environment detected by the illuminance sensor 15, that is, whether it is daytime or nighttime. The external camera 13 is operated with a constant exposure time.

  The reason is that, at the intersection where the traffic signal 19 exists, it is necessary to image the traffic signal 19 with priority over the traffic sign 20 even when the traffic sign 20 exists simultaneously. Since the traffic light 19 emits light by itself, it is possible to reliably recognize which color of the light emitting unit is lit by setting a constant exposure time regardless of the brightness of the outside world. Of the red, blue, and yellow light emitting portions of the traffic light 19, it is the red light emitting portion that needs to be recognized. However, if the exposure time is too long, the red color approaches white, and conversely the exposure time is too short. And red approaches black, both causing false detection.

  The exposure time setting unit M3 operates the external camera 13 with a predetermined exposure time determined according to the brightness of the external environment detected by the illuminance sensor 15 when the traffic signal presence / absence determination unit M2 determines that the traffic signal 19 does not exist. Let This exposure time is a map search using the illuminance detected by the illuminance sensor 15 as a parameter, and is set to a value that allows the traffic sign 20 to be clearly imaged even if the brightness of the outside world is different.

  The reason is that the traffic sign 20 reflects the light of the outside world without self-lighting with respect to the traffic light 19 that emits light. Therefore, when the outside is bright, the exposure time is shortened, and when the outside is dark. This is because the traffic sign 20 can be clearly imaged by increasing the exposure time.

  In this way, the traffic light state determination unit M4 to which the image data of the intersection where the traffic light 19 imaged by the external camera 13 is input is input from the RGB (red, green, blue) color space to the HSV (hue, saturation, luminance). ) Conversion to the color system is performed, and binarization processing is performed on the converted image data in the HSV color system to extract pixels having a predetermined red color or a predetermined luminance or higher. If the extracted pixel having a predetermined red color or a luminance higher than the predetermined luminance is a circle corresponding to the light emitting part of the traffic light 19 and is in the height direction where the light emitting part of the traffic light 19 is installed, the red signal is turned on. It is determined that

  In addition, the traffic sign type determination unit M5 to which the image data of the intersection where there is no traffic light 19 captured by the external camera is input generates an edge image by edge extraction processing according to the brightness of the pixels constituting the image data, and the edge A pattern matching process is performed to compare the image with the shape of the traffic sign 20 stored in the shape data storage means 14, and by recognizing the color of the pixel inside the edge image, a white character "pause" "Or a traffic sign 20 of" entrance prohibited "with a white line on a red background with a circle.

  On the other hand, the traveling control unit M6 to which the vehicle speed, yaw rate, brake pedal operation, steering angle, and the like detected by the own vehicle state detection unit 16 are input is displayed when the traffic signal 19 at the intersection is a red signal or when the intersection is "pause ”Or“ no entry ”traffic sign 20, if it is determined that there is a possibility that the vehicle is in an overspeed condition and will not stop before the intersection, the alarm device 18 is activated to inform the driver. In addition to issuing an alarm for prompting braking, when the driver does not perform a braking operation in response to the alarm, the braking device 17 is operated to automatically operate the wheel brake, and the vehicle is stopped before the intersection.

  Next, the operation of the intersection position determination unit M1, the traffic light presence / absence determination unit M2, and the exposure time setting unit M3 of the electronic control unit U will be further described with reference to the flowchart of FIG.

  First, in step S1, the navigation device 11 determines where the vehicle is on the map. When an intersection is present in front of the vehicle in step S2, the traffic light 19 is present at the intersection in step S3. If not, the exposure time of the external camera 13 is set to a value suitable for imaging the traffic sign 20 (a variable value corresponding to the brightness of the external environment) in step S4, and if the traffic light 19 exists at the intersection in step S3. In step S5, the exposure time of the external camera 13 is set to a value suitable for imaging of the traffic light 19 (a fixed value unrelated to the brightness of the external environment). In step S6, the external camera 13 captures the image with the set exposure time. Execute.

  As described above, when the traffic light 19 exists at the intersection, the exposure time of the external camera 13 is set to a fixed value, so that the color of the light emitting part of the traffic light that emits light at night or in the daytime can be changed. Recognized with certainty. When the traffic sign 20 is imaged because there is no traffic light 19 at the intersection, the exposure time of the external camera 13 is set according to the brightness of the external environment, so that the exposure amount is set to be small during the day and the exposure is performed at night. By setting the amount large, even the traffic sign 20 that does not emit light by itself can be surely recognized.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, although the exposure amount of the external camera 13 is controlled by the exposure time in the embodiment, it may be controlled by the aperture value.

Block diagram of a driving assistance device Flow chart for setting exposure time of external camera

Explanation of symbols

11 Navigation device (vehicle position specifying means)
12 Map information storage means 13 External camera (imaging means)
19 traffic light 20 traffic sign M3 exposure time setting part (control means)

Claims (2)

In the driving support device for recognizing the traffic light (19) and the traffic sign (20) based on the image captured by the imaging means (13) mounted on the vehicle,
Map information storage means (12) storing map information including the position of the intersection and the presence or absence of a traffic light (19) at the intersection;
Own vehicle position specifying means (11) for specifying the own vehicle position;
The traffic light (19) or the traffic sign (19) present at the intersection at a timing determined based on the map information stored in the map information storage means (12) and the own vehicle position specified by the own vehicle position specifying means (11). Imaging means (13) for imaging 20);
Control means (M3) for controlling the exposure amount of the imaging means according to whether the object of imaging is the traffic light (19) or the traffic sign (20);
A driving support apparatus comprising:   The control means (M3) sets a fixed exposure amount when the imaging target is the traffic light (19), and is variable according to the environment when the imaging target is the traffic sign (20). The driving support device according to claim 1, wherein an exposure amount is set.

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