JP2005337712A - Following distance detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a following distance detector which is free from constraints from car design and can be produced economically. <P>SOLUTION: Beside a rear view mirror 2 of a car 1, a light transmitter 3 is provided, and light receivers 6, 7 are provided in door mirrors 4, 5 projecting both the left and right of the car 1. The light projected by the light transmitter 3 is reflected at a rear bumper 8A of a preceding car 8 and received by the light receivers 6, 7. Thereby, the length L1 of the base line length between the light transmitter 3 and the light receivers 6, 7 is made longer than before. Consequently, the precision of measurement for measuring the following distance from the car 1 to the preceding car 8 measured by the method of triangular distance measurement is enhanced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inter-vehicle distance detection device for detecting a distance between, for example, a vehicle and a preceding vehicle traveling in front of the vehicle.

  Conventionally, an optical inter-vehicle distance detection device using an image sensor is disclosed in, for example, Patent Document 1. As shown in FIG. 7, the inter-vehicle distance detection device described in Patent Document 1 has two left and right optical systems, and the left and right optical systems are configured by lenses 100 and 200 arranged apart from each other by a base line length L. Has been. Separate image sensors 101 and 201 are provided at the focal lengths f of the lenses 100 and 200, and the signal processing device 300 electrically superimposes the image signals of the image sensors 101 and 201 while sequentially shifting them. Based on the principle of triangulation from the shift amount n when the image signals are best matched, the distance R to the object 700 is obtained by the formula R = f × L / n (hereinafter, this detection method is referred to as triangulation). This is called the distance method).

  Further, for example, Patent Document 2 discloses a method for measuring a distance between vehicles by infrared pulse irradiation. This inter-vehicle distance measurement method irradiates the object to be measured with near-infrared rays while changing in multiple directions, and determines the distance between the vehicle and the object to be measured from the time from when the near-infrared light is received to the reflected light from the object to be measured. It is what you want.

  Further, for example, Patent Literature 3 discloses a method for measuring a distance between vehicles by ultrasonic pulse irradiation. This inter-vehicle distance measurement method calculates the inter-vehicle distance based on the measurement result of the time from when a pulse signal such as a radio wave or a laser is sent to the front of the vehicle until the pulse signal reflected from the preceding vehicle is received. It is.

Furthermore, a method for measuring the distance between vehicles using a laser radar is disclosed in Patent Document 4, for example. According to this inter-vehicle distance measurement method, the laser radar generates laser pulse light from the laser diode on the transmission side, and emits the laser pulse light through the translucent lens. When there is an object such as an obstacle or a vehicle in the emission direction of the emitted pulsed light, the emitted pulsed light is reflected by the target and becomes reflected pulsed light. This reflected pulse light is detected by a photodiode through an optical filter on the receiving side. Then, the laser radar obtains a time difference between the reference signal and the light reception signal accompanying the emission of the laser pulse, and obtains the inter-vehicle distance based on this time difference.
JP-A-5-52561 (paragraphs 0002 and 0003, FIG. 1) JP-A-8-67223 (paragraph 0048, FIG. 6) JP-A-8-105973 (paragraph 0004, FIG. 13) Japanese Patent Laid-Open No. 9-243749 (paragraph 0002)

  By the way, the infrared pulse type, the ultrasonic pulse type, and the laser pulse type described in Patent Documents 2 to 4 can reduce the size of the apparatus. However, in these types, the entire apparatus becomes expensive, and as a result, the vehicle There is a problem that the overall price rises.

  On the other hand, in the inter-vehicle distance detection device described in Patent Document 1 that uses the triangulation method that has been used in low-price cameras and the like, if the device is made too small, the baseline length that affects the measurement accuracy is shortened and the detection is performed. There is a problem that accuracy decreases.

  In addition, in the triangulation system, the measurement accuracy on the short distance side is high, but the measurement accuracy on the long distance side tends to decrease, and this is because there is an inversely proportional relationship between the baseline length and the distance resolution. . Fortunately, the main purpose of detecting the distance between vehicles is a rear-end collision prevention device and its warning device, etc., and the detection accuracy at a short distance is required rather than the use at a long distance. Make the most of it. Therefore, although it is considered that this triangulation method is suitable as a low-cost inter-vehicle distance detection device, it is necessary to increase the base line length, which has a problem that this is an obstacle to the design of the vehicle. .

  In order to solve the above problems, the present invention provides an inter-vehicle distance detection device that can set a long base line length, can improve the detection accuracy of inter-vehicle distance by a triangulation method, and can be manufactured at low cost. The task is to do.

  The present invention is configured to solve the above-mentioned problems, and the invention according to claim 1 is provided on the left and right door mirrors provided on the left and right sides of the vehicle, and on or near the room mirror of the vehicle. A light emitter that emits light toward a preceding vehicle that travels in front of the vehicle, and a left and right light receiver that is provided on each of the left and right door mirrors and that receives light from the light emitter reflected by the preceding vehicle, and An inter-vehicle distance detection device comprising: a signal processing device that measures a distance from the vehicle to the preceding vehicle based on a triangulation principle using optical signals from the left and right light receivers.

  According to the first aspect of the present invention, the light emitted from the light emitting device provided in the vehicle rearview mirror or the vicinity thereof is reflected by the preceding vehicle and reflected, and the reflected light is provided in the left and right door mirrors. Is received. Then, the distance from the vehicle to the preceding vehicle can be measured by the signal processing device by the principle of triangulation using the optical signal from the light receiver. Here, since the light receiver is configured to be provided on the door mirror protruding from both the left and right sides of the vehicle, the light receiver is disposed between the light emitter and the left light receiver as compared with the case where the light receiver is provided, for example, in a vehicle bumper. The base line length and the base line length between the light emitter and the right light receiver can be set longer, and the detection accuracy of the inter-vehicle distance measured by the principle of triangulation can be improved. In addition, since the distance measurement data can be obtained separately using two light receivers, the distance measurement accuracy can be further improved by calculating these two distance measurement data.

  The invention according to claim 2 is directed to a preceding vehicle that is provided on either side of the left and right door mirrors provided on the left and right sides of the vehicle and one of the left and right door mirrors and travels in front of the vehicle. A light emitting device that emits light, a light receiving device that is provided on the other door mirror side of the left and right door mirrors and that receives light from the light emitting device reflected by the preceding vehicle, and an optical signal from the light receiving device is used. And a signal processing device for measuring the distance from the vehicle to the preceding vehicle based on the principle of triangulation.

  According to the invention described in claim 2, the light emitted from the light emitter provided on one door mirror of the vehicle is reflected by the preceding vehicle and reflected, and the reflected light is received by the light receiver provided on the other door mirror. Is done. Then, the distance from the vehicle to the preceding vehicle can be measured by the signal processing device by the principle of triangulation using the optical signal from the light receiver. Here, since the light emitter and the light receiver are provided on door mirrors protruding from the left and right sides of the vehicle, the light emitter and the light receiver are compared with the case where the light emitter and the light receiver are provided, for example, on a bumper of the vehicle. Can be set longer, and the detection accuracy of the inter-vehicle distance measured by the principle of triangulation can be increased.

  According to a third aspect of the present invention, the left and right door mirrors provided on the left and right sides of the vehicle and the front grille center of the bonnet tip of the vehicle or in the vicinity thereof are directed toward a preceding vehicle traveling in front of the vehicle. Light emitters that emit light, left and right door mirrors that are provided on the left and right door mirrors, respectively, that receive light from the light emitters reflected by the preceding vehicle, and light signals from the left and right light receivers are used. And a signal processing device for measuring the distance from the vehicle to the preceding vehicle based on the principle of triangulation.

  According to the third aspect of the present invention, the light emitted from the light emitting device provided at or near the center of the front grille of the vehicle hits and reflects the preceding vehicle, and the reflected light is provided on the left and right door mirrors. Light is received by the receiver. Then, the distance from the vehicle to the preceding vehicle can be measured by the signal processing device by the principle of triangulation using the optical signal from the light receiver. Here, since the light receiver is configured to be provided on the door mirror protruding from both the left and right sides of the vehicle, the light receiver is disposed between the light emitter and the left light receiver as compared with the case where the light receiver is provided, for example, in a vehicle bumper. The base line length and the base line length between the light emitter and the right light receiver can be set longer, and the detection accuracy of the inter-vehicle distance measured by the principle of triangulation can be improved. In addition, since the distance measurement data can be obtained separately using two light receivers, the distance measurement accuracy can be further improved by calculating these two distance measurement data.

  Since the light receiver is arranged on the door mirror, the base length can be set long, and the detection accuracy of the inter-vehicle distance by the triangulation method can be enhanced. Further, the design can be made without affecting the design around the front grille of the vehicle. Further, since the light receiver can be arranged away from the heat generating parts such as the engine and the headlamp, it is possible to simplify the heat countermeasure of the vehicle. Further, since the inter-vehicle distance measuring device using the triangulation method is employed, it can be manufactured at a lower cost than the inter-vehicle distance measuring device using the infrared pulse type, ultrasonic pulse type, or laser pulse type.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a plan view showing a vehicle on which the inter-vehicle distance detection device according to the present embodiment is mounted and a preceding vehicle traveling in front of the vehicle, and FIG. 2 is a perspective view showing the vehicle in FIG. FIG. 3 is a perspective view showing the door mirror of the vehicle in FIG. 1, and FIG. 4 is an explanatory view showing the relationship between the inter-vehicle distance and the distance measurement accuracy.

  As shown in FIG. 1, the inter-vehicle distance detection device used in the present embodiment includes a light emitter 3 (see FIG. 2) composed of an infrared LED (Light Emitting Diode) provided near a room mirror 2 of a vehicle 1. The left and right light receivers 6 and 7 comprising CCDs (Charge Coupled Devices) provided in the left and right door mirrors 4 and 5 of the vehicle 1 and the left and right light receivers 6 and 7 mounted on the vehicle 1 are connected. And a signal processing device (not shown). The light emitter 3 may be provided directly on the room mirror 2. Further, the light emitter 3 is preferably installed on the center line of the vehicle 1.

  Here, as shown in FIG. 1, the light emitter 3 emits light such as infrared rays toward the rear bumper 8 </ b> A of the preceding vehicle 8 that travels in front of the vehicle 1. Further, as shown in FIG. 3, the left light receiver 6 is incorporated in a box-shaped mirror housing 4 </ b> A for mounting a mirror (not shown) of the door mirror 4. The mirror housing 4A is provided with a through hole 4B so that the light from the light emitter 3 reflected by the rear bumper 8A of the preceding vehicle 8 passes through the through hole 4B and is received by the light receiver 6. Yes. Similarly to the left light receiver 6, the right light receiver 7 is incorporated in the mirror housing 5 </ b> A of the door mirror 5, and receives light from the light emitter 3 reflected by the rear bumper 8 </ b> A of the preceding vehicle 8. It has become. The through-hole 4B may be provided with a lens for guiding light to the CCD, or this lens may be integrally formed with a turn lamp lens to have the same design surface.

  Further, the signal processing device uses the optical signal from the light receiver 6 and the base line length L1 between the light emitter 3 and the light receiver 6 from the vehicle 1 according to the principle of triangulation disclosed in Patent Document 1. The distance to the preceding vehicle 8 is measured. Further, this signal processing device uses the optical signal from the light receiver 7 and the base line length L1 between the light emitter 3 and the light receiver 7 to determine the distance between the vehicle 1 and the preceding vehicle 8 according to the principle of triangulation. It measures distance.

  Next, the operation of the inter-vehicle distance detection device used in this embodiment configured as described above will be described with reference to FIG. In FIG. 4, reference numeral 400 denotes a conventional light receiver, reference numeral Y1 denotes a vehicle at a long distance from the light emitter 3, reference numeral Y2 denotes a vehicle at a short distance from the light emitter 3, and reference numeral d1 denotes the light emitter 3 and the light receiver 7. The base line length between them, the symbol d2, is the base line length between the light emitter 3 and the light receiver 400. Since the light receiver 7 used in the present embodiment provided on the door mirror is disposed at a position farther in the vehicle width direction from the light emitter 3 than the conventional light receiver 400 provided in a bumper or the like, the relationship of d1> d2 is established. It is in. Reference sign ΔY is the amount of change in the inter-vehicle distance, reference sign ΔX1 is the width dimension in the X direction of the light irradiated from the vehicles Y1, Y2 through the light receiver 7 onto the line sensor surface, and reference sign ΔX2 is the light receiver 400 from the vehicles Y1, Y2. The width dimension of the X direction of the light irradiated on a line sensor surface through is shown. Since the baseline length d1 is longer than the baseline length d2, there is a relationship of ΔX1> ΔX2.

And as you can see from Figure 4,
d1: d2≈ΔX1: ΔX2 (Formula 1)
The relationship holds. Therefore, as the baseline length increases from d2 to d1, the distance measurement accuracy decreases from ΔY / ΔX2 to ΔY / ΔX1, and high-accuracy measurement can be performed. Moreover, the incident angle of the light to the light receiver 7 can be made larger in the vicinity of the vehicle Y2 than in the vicinity of the vehicle Y1, and the accuracy on the short distance side of the vehicle Y2 can be improved.

  As described above, in the present embodiment, since the light receivers 6 and 7 are incorporated in the left and right door mirrors 4 and 5 protruding in the width direction from the left and right sides of the vehicle 1, conventional light reception provided in a bumper or the like of the vehicle 1 is performed. The base line length can be set to be longer than that of the machine 400, whereby the distance measurement accuracy of the inter-vehicle distance between the vehicle 1 and the preceding vehicle 8 can be improved. Therefore, the design can be made without affecting the design around the front grille of the vehicle 1. Further, since the light receivers 6 and 7 can be arranged away from the heat generating parts such as the engine and the headlamp, the heat countermeasure of the vehicle 1 can be simplified. Further, by arranging the light emitter 3 at the center of the vehicle 1 and the light receivers 6 and 7 at symmetrical positions, the distance measurement data from the two light receivers 6 and 7 use the same baseline length L. The distance measurement accuracy can be further improved by calculating two distance measurement data. Furthermore, since the inter-vehicle distance measuring device using the triangulation method is employed, the inter-vehicle distance measuring device using the infrared pulse method, the ultrasonic pulse method, or the laser pulse method can be manufactured at a lower cost. Even if an obstacle such as a motorcycle enters between the light receiver 6 and the preceding vehicle 8 among the light receivers 6 and 7 and the inter-vehicle distance cannot be detected, the inter-vehicle distance is detected using the other light receiver 7. Can be detected with high accuracy.

(Second Embodiment)
Next, FIG. 5 shows a second embodiment of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 5 is a plan view showing a vehicle on which the inter-vehicle distance detection device according to the present embodiment is mounted and a preceding vehicle that travels in front of the vehicle. As shown in FIG. 5, the inter-vehicle distance detection device used in the present embodiment includes a light emitter 24 provided in the left door mirror 22 of the left and right door mirrors 22, 23 of the vehicle 21, and a right door mirror 23. A light receiver 25 provided inside, and a signal processing device (not shown) mounted on the vehicle 21 and connected to the light receiver 25 are provided.

  Here, the light receiver 25 receives light from the light emitter 24 reflected by the rear bumper 8A of the preceding vehicle 8 and reflected. And the said signal processing apparatus is based on the principle of the triangulation disclosed by patent document 1 using the optical signal from the light receiver 25, and the base line length L2 between the light emitter 24 and the light receiver 25 from the vehicle 21. The inter-vehicle distance to the preceding vehicle 8 is measured.

  Next, the operation of the inter-vehicle distance detection device used in the present embodiment configured as described above will be described with reference to FIG. In FIG. 6, reference numeral 500 represents a conventional light emitter, reference numeral 600 represents a conventional light receiver, reference numeral Y1 represents a vehicle at a distance from the light emitter 24, reference numeral Y2 represents a vehicle at a short distance from the light emitter 24, and reference numeral d1 ' The base line length between the light emitter 24 and the light receiver 25, the symbol d <b> 2 ′, is the base line length between the light emitter 500 and the light receiver 600. The light emitter 24 and the light receiver 25 used in the present embodiment provided in the door mirrors 22 and 23 are arranged at positions farther in the vehicle width direction than the conventional light emitter 500 and the light receiver 600 provided in a bumper or the like. Therefore, the relationship is d1 ′> d2 ′. Reference sign ΔY is the amount of change in the inter-vehicle distance, reference sign ΔX1 ′ is the width dimension in the X direction of the light irradiated on the line sensor surface from the vehicles Y1 and Y2 through the light emitter 24 (light receiver 25), and reference sign ΔX2 ′ is the vehicle. The width dimension of the X direction of the light irradiated on the line sensor surface through the light-emitting device 500 (light-receiving device 600) from Y1, Y2 is shown. Since the base line length d1 ′ is longer than the base line length d2 ′, there is a relationship of ΔX1 ′> ΔX2 ′.

And as you can see from Figure 6,
d1 ′: d2′≈ΔX1 ′: ΔX2 ′ (Expression 2)
The relationship holds. Therefore, as the baseline length increases from d2 ′ to d1 ′, the distance measurement accuracy decreases from ΔY / ΔX2 ′ to ΔY / ΔX1 ′, and high-accuracy measurement can be performed. Moreover, the incident angle of the light to the light receiver 25 can be larger in the vicinity of the vehicle Y2 than in the vicinity of the vehicle Y1, and the accuracy on the short distance side of the vehicle Y2 can be increased.

  Also in this embodiment configured as described above, since the light emitter 24 and the light receiver 25 are provided on the door mirrors 22 and 23 protruding from the vehicle 21 on the left and right sides, respectively, the space between the light emitter 24 and the light receiver 25 is provided. The base line length L2 can be set longer than the conventional one, the distance measurement accuracy of the inter-vehicle distance can be improved, and substantially the same effect as in the first embodiment can be obtained.

  In the first embodiment, the case where the light emitter 24 is arranged on the side of the door mirror 22 has been described as an example. However, the present invention is not limited to this, for example, as shown in FIG. The light emitter 24 ′ may be arranged near the center of the front grill of the vehicle 1.

In the second embodiment, the case where the light emitter 24 is provided in the left door mirror 22 and the light receiver 25 is provided in the right door mirror 23 has been described as an example. However, the present invention is not limited thereto. For example, the light receiving device 25 may be provided on the left door mirror 22 and the light emitting device 24 may be provided on the right door mirror 23.
Further, the door mirrors 4, 5, 22, and 23 of the first and second embodiments may be installed at positions protruding from the left and right sides of the vehicle body, for example, a fender mirror installed on a hood. But you can.

It is a top view which shows the vehicle by which the inter-vehicle distance detection apparatus which concerns on 1st Embodiment is mounted, and the preceding vehicle which drive | works before it. It is a perspective view which shows the vehicle in FIG. It is a perspective view which shows the door mirror of the vehicle in FIG. It is explanatory drawing which shows the relationship between the inter-vehicle distance which concerns on 1st Embodiment, and ranging accuracy. It is a top view which shows the vehicle by which the inter-vehicle distance detection apparatus which concerns on 2nd Embodiment is mounted, and the preceding vehicle which drive | works before it. It is explanatory drawing which shows the relationship between the inter-vehicle distance which concerns on 2nd Embodiment, and ranging accuracy. It is a schematic diagram which shows the inter-vehicle distance detection apparatus by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Room mirror 3, 24, 24 'Light emitter 4, 5, 22, 23 Door mirror 6, 7, 25 Light receiver 8 Leading vehicle L1, L2 Baseline length

Claims (3)

Left and right door mirrors on the left and right sides of the vehicle,
A light emitting device that is provided in or near the vehicle rearview mirror and emits light toward a preceding vehicle that travels in front of the vehicle;
Left and right light receivers that are respectively provided on the left and right door mirrors and receive light from the light emitters that have been reflected by the preceding vehicle, and
An inter-vehicle distance detection device comprising: a signal processing device that measures a distance from the vehicle to the preceding vehicle by using a triangulation principle using optical signals from the left and right light receivers. Left and right door mirrors on the left and right sides of the vehicle,
A light emitting device that is provided on one of the left and right door mirrors and emits light toward a preceding vehicle that travels in front of the vehicle;
A light receiver that is provided on the other door mirror side of the left and right door mirrors and that receives light from the light emitter reflected by the preceding vehicle;
An inter-vehicle distance detection device comprising: a signal processing device that measures a distance from the vehicle to the preceding vehicle based on a principle of triangulation using an optical signal from the light receiver. Left and right door mirrors on the left and right sides of the vehicle,
A light emitting device that is provided at or near the front grill center of the bonnet tip of the vehicle and emits light toward a preceding vehicle that travels in front of the vehicle;
Left and right light receivers that are respectively provided on the left and right door mirrors and receive light from the light emitters that have been reflected by the preceding vehicle, and
An inter-vehicle distance detection device comprising: a signal processing device that measures a distance from the vehicle to the preceding vehicle by using a triangulation principle using optical signals from the left and right light receivers.

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