JPH1137752A - Distance detection device - Google Patents

Abstract

(57) [Summary] (With correction) [Problem] To provide an inexpensive distance detecting device capable of recognizing not only the distance between vehicles but also the position of a white line on a road. The device has a lens, and separator lenses for forming an image of an object to be measured formed by the lens on the CCDs.
The difference (l ₀ −l) between the imaging interval l ₀ in the focused state on 25b and the imaging interval l of the object to be measured is electrically detected,
The measurement distance L is calculated from the difference (l ₀ −l), and the CCDs 25a and 25b, the separator lens 24a,
A plurality of 24b are arranged in a direction orthogonal to the scanning direction to enable distance detection of a large number of locations by one scanning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance detecting means for measuring an inter-vehicle distance of a running vehicle.

[0002]

2. Description of the Related Art The near future ITS (intilligen)
ttransportationsystem). A
HS (automatic highway system)
Based on em), the necessity of a sensor for detecting the surroundings of a vehicle has been increased, and various sensors have been proposed. Automakers and component manufacturers are studying for practical use. To show an example, a. Infrared laser radar, b.
Millimeter wave radar, c. Image recognition, d. A distance measuring device using an ultrasonic sensor or the like has been proposed.

[0003]

However, as shown in Table 1, the fact is that each of them has advantages and disadvantages and there is no decisive sensor.

[0004]

【table 1】

That is, a. b. Is suitable for distance measurement, but cannot recognize lanes. Further, a. Cannot be used in rainy fog. c. Can recognize the lane and receive the entire surroundings, but it is difficult to judge the car or obstacle ahead and to detect the distance, and the price is considered to be considerably high. d. Is excellent in the range of several tens cm to several meters, but cannot be used in the range of several meters to several tens of meters required during traveling.

[0006] In view of the above, a method of compensating for a defect by combining a plurality of sensors has been studied. However, there are problems such as a complicated system and an increase in cost.

The present invention has been proposed in view of the above problems, and has as its object to provide an inexpensive, effective detection distance, and a vehicle distance detection device capable of lane recognition. I have.

[0008]

The above objects are achieved by the present invention described below.

(1) A distance detecting device mounted on a vehicle, wherein a plurality of sets of lenses for imaging an object to be measured and a plurality of sets are arranged in a direction orthogonal to an optical axis of the lenses. An imaging lens for re-imaging each, an inter-imaging distance detecting means provided for each of the plurality of pairs of imaging lenses, for detecting an interval of imaging by the imaging lenses, And a distance calculating means for calculating a distance from the lens to the object to be measured based on the obtained inter-image distance.

(2) The inter-image distance detecting means has a photoelectric conversion element for converting an image forming position of the image forming lens into an electric signal, and an interval calculating means for calculating an inter-image distance from the image forming position. The distance detection device according to the above (1).

(3) The image forming apparatus according to the above (1), further comprising: a single body in which the imaging lens and the photoelectric conversion element are integrated, and a scanning drive unit that scans the single body in a direction orthogonal to the arrangement direction of the imaging lens. The distance detection device according to 2).

(4) The distance calculating means has a color detecting means for detecting a difference in color of the image, specifies an object to be measured based on the detected color difference, and The distance detecting device according to any one of (1) to (3), wherein a distance from the lens to the object to be measured is calculated based on an inter-image distance of an image of the object.

(5) The distance detection according to the above (4), wherein the color detection means and the inter-image distance detection means are determined based on an image formed through the same imaging lens. apparatus.

(6) The distance detecting device according to the above (4) or (5), wherein the color detecting means judges a white line or a yellow color of the road based on a difference in color of an image.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a side sectional view showing a main part of an optical system of a distance measuring device mounted on a vehicle, which is a distance detecting device 1 according to the present invention. The optical system includes a lens barrel 10, a lens 11 fitted and supported on one end face of the lens barrel 10, and a sensor module 2 housed in the lens barrel 10 as a single unit. The sensor module 2 includes, in order from the lens 11 side, a film equivalent surface 21,
Field mask 22, condenser lens 23, aperture mask 2
6. A pair of separator lenses 24 as imaging lenses
a, 24b, CCD (Charg) as photoelectric conversion element
e Coupled Device) 25 is the lens 1
They are arranged on one optical axis.

The field mask 22 includes two imaging lenses 24.
This is to prevent the light beams passing through a and 24b from interfering with each other. The condenser lens 23 projects the image of the aperture mask 26 on the pupil plane of the lens 11,
Only the luminous flux that has passed through a specific aperture is CCD 25a, 25b
It is for imaging up. The aperture mask 26 is
This regulates the luminous flux formed on the CCDs 25a and 25b. The separator lenses 24a and 24b divide the subject image on the film equivalent surface into two parts and form them on the reference part 25b and the reference part 25a on the CCD, respectively. In addition, the CCD 25 of the present embodiment has 128 CCDs.
A subject formed of pixels and formed on the CCDs 25a and 25b is photoelectrically converted into image information. Also, 12
The use of the eight pixels is divided into two areas for the reference portion 25b and the reference portion 25a.

In the distance detecting apparatus 1 of the present invention, the separator lenses 24a and 24b and the CCDs 25a and 25b
A plurality are arranged vertically. Thus, a vertical angle can be provided in the scanning direction, and it is not necessary to provide a driving device for rotating the entire apparatus 1 in the vertical direction.

FIG. 2 is a perspective view and a side view showing the positional relationship of the components of the optical system of the distance detecting device 1. As shown in FIG. As shown in FIG.
In this embodiment, four CCDs a and 24b and four CCDs 25a and 25b are arranged in the vertical direction (vertical direction) according to the vertical scanning angles β0, β1, β2, and β3.

Here, β indicates an angle with respect to the horizontal direction, β0 is an angle for scanning in the horizontal direction, β1 is an angle for scanning a road surface 20 m ahead of the vehicle, and β2 is an angle for scanning 10 m ahead of the vehicle. Angle when scanning the road surface, β3
Indicates the angle when scanning a road surface 5 m ahead of the vehicle, and in the present embodiment, these scanning angles β0, β
1, β2 and β3 are determined in advance. Therefore, CCD
At 0, the image of the object located in the horizontal direction is formed, and the CCD
1 forms an image of a road surface 20 m ahead of the vehicle (for example, the presence or absence of a white line), CCD2 forms an image of a road surface 10 m ahead of the vehicle, and CCD3 forms a road surface 5 m ahead of the vehicle. The state forms an image.

In the case of CCD1 to CCD3 for viewing the road surface,
Since the detection distance can be limited on the premise that the road surface is flat, a clear image can be formed on the CCD by setting the specifications such as the focal length and aberration correction of the separator lens corresponding to each distance, The recognition of the white line can be ensured. Also, as a practical problem, there is a slope on the road surface, manufacturing error and mounting error of the sensor, height and tilt of the mounted car also constantly fluctuate depending on running conditions, passengers, etc. Defocus can be minimized.

Hereinafter, a method for detecting the distance to the subject will be described with reference to FIG. Regarding the lens 11, (1 / L)
-(1 / b) = 1 / f: Equation 1 holds, and d =
(Fv / β) * (l ₀ −l): Equation 2 holds. Here, L is the distance to the subject S, b is the distance from the lens 11 to the imaging point 01, f is the focal length, d is the defocus amount, Fv is a predetermined variable, γ is the separator lens 24a,
The magnification of 24b, l ₀ is the imaging interval at the time of focusing, and l is d
This is only the imaging interval at the time of front focus.

FIG. 3 shows that d = c−b.
Is substituted, c−b = (Fv / γ) * (l ₀ −l): Expression 3. Also, by transforming Equation 1, 1 / b = (1 / L)
− (1 / f): Equation 4 is obtained, and from Equations 3 and 4, L = 1 /
(1 / f + 1 / (c− (Fv / γ) * (l ₀ −l)))
Next, the imaging interval l, the distance L from l ₀ to the subject is obtained.

On the other hand, as shown in FIG. 4, the distance detecting unit integrally formed in the lens barrel 10 is detected by the left-right scanning drive means 31 in the right-left direction with respect to the traveling direction of the vehicle. The scanning drive means 31 has a built-in sensor for detecting the scanning angle.

As shown in FIG. 4, the image forming interval 1 detected by the distance detecting unit alone is calculated by the interval calculating means 41.
In the calculation, the distance to the subject is detected based on the image forming interval. The color detecting means is constituted by CCDs 25a and 25b and an interval calculating means.

The means for detecting the distance between the imagings includes CCDs 25a,
5b and the interval calculation means 41. In addition, in the detection direction conversion means 42, the scanning angles are calculated based on the signal input from the sensor. For example, as shown in FIG. 6, these scanning angles α and the distance L to the detected subject are calculated. ', A distance L in a direction parallel to the traveling direction of the vehicle is obtained from L'cosα.

Such calculations are performed by the central processing unit 43. In the central processing unit 43, the detected vehicle interval L and scanning direction α are output to another vehicle system 5 by the output device 44 and used for other vehicle control and the like. For example, it is supplied to a system control such as an engine control device and a gear position control device, and a voice warning device for calling attention to an inter-vehicle distance.

The control operation of the central control unit 43 will now be described with reference to the flowchart shown in FIG.
This will be described with reference to the schematic diagram shown in FIG. First, in step S1, related data such as an initial value is read. Specifically, data unique to an individual sensor such as an adjustment value at the time of manufacturing or mounting the sensor is given.

In step S3, the sensor is scanned from left to right to obtain an output from the CCD 25. The scanning range (angle) varies depending on the vehicle speed, congestion status, and the like, but here, the description will be made assuming that αm = ± 20 °. By this one scan, outputs are obtained from the four CCDs 25 arranged vertically. From the CCD0, the distance between the vehicles in the horizontal direction, from the CCD1, the road surface condition 20 m ahead when scanned at the scan angle β1, from the CCD2, the road surface condition 10m ahead when scanned at the scan angle β2, CCD3
, CCD outputs representing the road surface state 5 m ahead when scanning at the scanning angle β3 are obtained.

Then, the outputs obtained for each of CCD0 to CCD3 are processed as follows, and finally output to the vehicle system (step S13). The case of processing the output of CCD0 scanned in the horizontal direction will be described.
Output is made as shown in FIG. 7 corresponding to the image forming position interval l appearing on the CCD 0 and the scanning direction α. L shown in FIG.
L ′ is obtained from a map indicating the relationship between L ′ and L ′, and as described above, L = L′ cosα, and the scanning direction α,
The relationship between the inter-vehicle distances L is obtained as shown in FIG. 9 (step S5). By this step S5, a function as a distance calculating means is exhibited.

Next, in step S7, the relative vehicle speed ΔV is obtained using the inter-vehicle distance L (t−Δt) before the time Δt. That is, the amount of change [L
(T) −L (t−Δt)] by Δt,
The relative vehicle speed ΔV is obtained as shown in FIG.

On the other hand, a color component is detected from the output of the CCD 0 (step S9). The detection value in step S9 includes not only the brightness of the light but also the detection of the color component.
For example, detection of a red component and detection of a white component are performed.
When determining the color component, a filter that allows light of a predetermined color to pass is mounted in front of the CCD. For example, a red filter is attached to determine red.

Next, an object to be detected is determined based on the relative speed obtained in step S7 and the color components obtained in step S9 (step S11). For example, if the relative speed is the same as the vehicle speed, it can be determined that the object is stationary, and if a white component is detected, it can be determined that the object is a guardrail. Alternatively, when the red component is detected, it can be determined that the vehicle is a tail lamp of a vehicle, and the detection target can be determined to be a vehicle. That is, the detection target can be specified according to various color components. Further, by taking into account the relative speed, it is possible to make a more accurate determination.

In addition to the above, a stopped car, a person, a bicycle,
Guardrails, debris, etc. can also be determined. Based on the above result, the obtained information is output to the vehicle system. (Step S13). In the vehicle system, for example, the following control can be performed based on this information (see FIGS. 6 and 10).

First, the judgment of the situation is as follows.
B = 0) The vehicle is traveling ahead with the inter-vehicle distance LB, and although there is room for the dangerous inter-vehicle distance Ls, the car A (own vehicle) is approaching at the relative vehicle speed−ΔVB (= VB−VA). Attention is needed. Car C is in the overtaking lane with the following distance LC, relative vehicle speed △ V
C (VC-VA) is moving away and it is safe first.
Vehicle D is at relative vehicle speed △ VD (= VD-VA) =-VA, that is, it is stopped at the shoulder of the road, and the distance is short by LD.

On the vehicle side, based on the above judgment, the driver is alerted by auditory information (sound, voice) and visual display (lamp lighting, blinking, language display, etc.) from the above information, and emits a warning or warning sound when approached further. .

Alternatively, in addition to or instead of the above-described notification operation, in the automatic transmission, downshifting may be performed to apply engine braking to assist in deceleration. In the notification operation, the engine brake may be applied by downshifting after notifying that deceleration by the engine brake is performed.

Further, not only the engine brake by downshifting but also an automatic brake for automatically applying a foot brake may be operated. Furthermore, automatic steering may be operated to automatically operate the steering. Furthermore, in addition to the above-described embodiment, various methods are conceivable depending on situations or systems.

Next, the case of processing the outputs of the CCD1 to CCD3 will be described. First, a case where processing is performed based on the output of the CCD 1 will be described as a representative example. Other CCD2
Processes based on the output of the CCD 3 are the same as those in the case of the CCD 1, and thus the description thereof is omitted.

The position of the white line is detected (step S15-).
1). The white line recognition method is a method in which a white line is defined as a bright portion in a road area by image processing, and a determination is made based on a gray level. In the embodiment, the determination is made based on the edge reference.

FIG. 11 shows a case where two white lines 6 are scanned. The edge is a part of the image where the change in shading is sufficiently large, that is, outlines 61 and 62, and has an advantage that even if the absolute amount of shading changes due to a shadow or dirt, the effect is small. There are two types of edges, positive and negative, depending on the gradient of the shading change. In FIG. 11, the case where the β1 direction is scanned from left to right will be described.
When scanning is performed, the dark portion of the asphalt changes from a dark portion to a bright portion of a white line, so that the positive edge 63 can be detected. Subsequently, at the right end of the white line, since the light portion changes from a bright portion to a dark portion, a negative edge 64 is detected.

In this manner, the position of the white line can be detected in the β1 direction corresponding to the left and right α directions. Further, if scanning is performed to the right side, detection can be performed in accordance with the position of the white line on the right side and the angle α. When a white line is detected (step S
15-1: Y), the process proceeds to the determination in step S17-1, and if no white line is detected (step S15-
1: N) is returned.

Next, the direction and the distance of the detected white line are calculated (step S17-1). The distance measurement is performed in the same manner as in step S5, using the received light intensity by the white line as a guide. The above processing is performed for CCs corresponding to the scan angles β1 to β3.
This is performed for each output of D1 to CCD3. For example, referring to the schematic diagram shown in FIG.
The output of D3 is an intersection P ₁₁ to P ₁₄ of the scanning lines R ₁ to R ₄ in the lateral direction of the scan angle _{α1~α4, P 21 ~P 22, P} 31
For to P _32, it is outputted as shown in FIG. 13 (B) ~ (D) .

From the output, the position of the own vehicle and the positional relationship between the white line and the preceding vehicle B are detected (step S19). Specifically, a positional relationship as shown in FIG. 14 is assumed. The preceding vehicle has a distance LB in the direction of αB, and P ₃₂ −P
₂₂ -P ₁₃ points curvature in each direction and white line 6b can be estimated from the distance, and P ₃₁ -P ₂₁ can be determined similarly to the other one of white lines 6a state from point -P _12. From these two situations, the position of the own vehicle with respect to the traveling lane and the direction with respect to the lane are also known. Further, it is possible to determine whether the preceding vehicle B is traveling on the same lane as the own vehicle or on another lane.

Then, the positional relationship and the direction are supplied to another vehicle system (step S13). In the vehicle system, for example, the following control can be performed. It is determined whether there is a possibility that the vehicle deviates from the driving lane, and if it is predicted that the vehicle is likely to deviate, the driver can be warned. In the case of an autonomous vehicle in which braking, steering, and the like are automated, the vehicle can automatically return to the lane.

In particular, in the distance detecting apparatus 1 of the present invention, the above-described determination can be made based on the result of one scan, so that the vehicle control sensitive to the change of the traveling environment can be performed. Even during traveling, a quick control operation can be ensured.

[0046]

According to the distance detecting apparatus of the present invention described above, it is possible to detect both the distance to the subject such as the inter-vehicle distance and the position of the vehicle with respect to the traveling lane by using an inexpensive apparatus. . In particular, since the inter-image distance detecting means for detecting the inter-image distance of the image is arranged at a position corresponding to the scanning position in the front-rear direction of the road surface, without providing a configuration for driving the entire apparatus up and down, The whole structure can be simplified, and downsizing and cost reduction can be achieved.

Further, since a single scanning can scan the scanning positions located in the front-back direction at the same time, it is possible to control the vehicle sensitively to the change of the traveling environment. Further, by adopting a configuration in which the content of the measured object is determined according to the color intensity of the measured object, more accurate vehicle control can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an optical system according to the present invention.

FIG. 2 is a perspective view and a side view showing a configuration of an optical system according to the present invention.

FIG. 3 is an explanatory diagram showing a main part of the optical system of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a control system according to the present invention.

FIG. 5 is a flowchart.

FIG. 6 is a schematic diagram showing an inter-vehicle distance for explaining a scanning method of the apparatus of the present invention.

FIG. 7 is an explanatory diagram showing an imaging distance detected by a CCD.

FIG. 8 is a graph showing a relationship between an imaging distance and a subject distance.

FIG. 9 is an explanatory diagram showing an inter-vehicle distance obtained based on an imaging distance.

FIG. 10 is an explanatory diagram showing a calculated relative speed.

FIG. 11 is an explanatory diagram showing a state in which a white line is recognized.

FIG. 12 illustrates a scanning method of the apparatus of the present invention.
It is a schematic diagram which shows the distance between vehicles.

FIG. 13 is a reference diagram showing an output state of each CCD.

FIG. 14 is a schematic diagram showing a positional relationship between a host vehicle and a preceding vehicle obtained as a result of scanning.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Distance detection device 10 Lens tube 2 Sensor module 23 Condenser lens 24 Separator lens (imaging lens) 25 CCD 43 Central processing unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Keiichi Kimura Inventor Equos Research Co., Ltd. 2--19-12 Sotokanda, Chiyoda-ku, Tokyo (72) Inventor Tomoaki Ikeyama 2--19 Sotokanda, Chiyoda-ku, Tokyo 12 Equos Research Co., Ltd.

Claims (6)

[Claims] 1. A distance detecting device mounted on a vehicle, comprising: a lens for imaging an object to be measured; and a plurality of sets arranged in a direction orthogonal to an optical axis of the lens. An image forming lens for each re-imaging, and a plurality of image forming lenses,
A distance detecting device comprising: an inter-image distance detecting means for detecting an interval between images formed by the imaging lens; and a distance calculating means for calculating a distance from the lens to the object to be measured based on the detected inter-image distance. . 2. An image forming apparatus according to claim 1, wherein said inter-image distance detecting means includes a photoelectric conversion element for converting an image forming position of the image forming lens into an electric signal, and an interval calculating means for calculating an inter-image distance from the image forming position. Item 2. The distance detecting device according to Item 1. 3. The image forming apparatus according to claim 2, further comprising: a single unit in which the imaging lens and the photoelectric conversion element are integrated, and a scan driving unit that scans the single unit in a direction orthogonal to the arrangement direction of the imaging lens. 3. The distance detecting device according to 1. 4. The distance calculating means has a color detecting means for detecting a difference in color of the image, and specifies an object to be measured based on the detected color difference. The distance detecting apparatus according to claim 1, wherein a distance from the lens to the object to be measured is calculated based on an inter-image distance of the imaging. 5. The distance detecting apparatus according to claim 4, wherein said color detecting means and said inter-image distance detecting means are determined based on an image formed through the same image forming lens. 6. The distance detecting apparatus according to claim 4, wherein said color detecting means determines a white line or a yellow color of the road based on a difference in image color.