JP3441342B2 - Vehicle distance measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring device for a vehicle, and more particularly, it compares the image signals in a window of a pair of images formed on an image sensor by a pair of optical systems to compare the light of both images. The present invention relates to a vehicle distance measuring device that electrically detects a deviation amount from an axis and executes a calculation based on the principle of triangulation using the deviation amount to measure a distance to an object.

[0002]

2. Description of the Related Art Conventionally, such a distance measuring device is already known, for example, from Japanese Patent Application Laid-Open No. 5-296767, and in this device, the object of distance measurement changes, that is, the vehicle between the preceding vehicle and the vehicle. In order to cope with the interruption of, the image is tracked by determining the left-right symmetry of the image of the target window, and the movement of the front vehicle is estimated by adding the information of multiple windows. I am trying.

[0003]

However, in the above-mentioned conventional vehicle, when a vehicle interrupted between the preceding vehicle and the host vehicle slips beside the preceding vehicle while the preceding vehicle is stopped, the slipped vehicle May be tracked as an object and may continue to output the distance of the interrupting vehicle instead of the preceding vehicle existing ahead after the vehicle has slipped through.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a vehicle distance measuring device capable of reliably measuring the distance of a vehicle ahead when an interruption vehicle slips through. And

[0005]

To achieve the above object, the present invention compares the image signals in a window of a pair of images formed on an image sensor by a pair of optical systems and compares both images. In the vehicle distance measuring device that electrically detects the deviation amount from the optical axis and executes the calculation based on the principle of triangulation using the deviation amount to measure the distance to the object, the image determined by the window Lane change determination means for determining whether or not a lane change has occurred for a vehicle whose distance has been measured when there are a plurality of target vehicles in the area, and an object within the image area defined by the window When there are a plurality of vehicles, when the lane change is determined by the lane change determination means and an interrupt determination means that determines whether or not another vehicle interrupts between the vehicle that was the object of distance measurement and the own vehicle Distance measurement The subject with change in the vehicle other than the lane change the vehicle and a target switching means for changing the interrupt vehicle target distance measured when it is determined that the interrupt in the interrupt determining means, said target switching means, In front of my car
If the target object is a vehicle of a certain width or less, such as a motorcycle,
If the distance to the target is less than a certain value,
Decides not to track as a target for distance measurement, but that
When it is other than, it is determined that it will be tracked as a target of distance measurement.
The first feature is that the above-mentioned vehicle distance measuring device
In the image area defined by the window,
It was the target of distance measurement when there were multiple vehicles
Lane change to determine if the vehicle's lane change has occurred
The determination means and the object within the image area defined by the window
Is the target of distance measurement when there are multiple vehicles.
Determining whether interrupted by other vehicles in the vehicle and the own vehicle was
Lane change determination means and lane change determination means
When the judgment is made, the target of distance measurement is
When changing to a vehicle and interrupting with the interrupt determination means
Change the target of distance measurement to the interrupting vehicle when judged
And a target switching means for controlling the target switching means.
When the motorcycle is located relatively close to the front of the vehicle
Is not tracked as a target for distance measurement, but
If there is a motorcycle at a relatively distant position,
Vehicles such as passenger cars and trucks whose width exceeds a certain value in front of
If both are present, they can be tracked as targets for distance measurement.
And are the second characteristics.

With such a configuration, when there are a plurality of vehicles as objects in the image area defined by the window, the lane change determining means determines the lane change and the interrupt determining means determines that the vehicle is interrupted. If it is determined that it is a lane change, a vehicle other than the lane change vehicle is selected as a target vehicle for distance measurement, and if it is determined that the vehicle interrupts, an interrupting vehicle is selected as a distance measurement target. When a vehicle interrupts between its own vehicle and the preceding vehicle, the distance of the interrupting vehicle can be measured, and the interrupting vehicle can slip past the side of another preceding vehicle that was in front of the interrupting vehicle due to a lane change. In this case, the vehicle whose distance is to be measured can be switched from the passing vehicle that has passed through to another preceding vehicle that exists in front of the vehicle. And, in particular, according to the first feature
In this case, the object in front of the vehicle is of a certain width, such as a motorcycle.
In the case of the following vehicles, and the distance to the object is below a certain value
If it is, it is determined that the object is not tracked as a target for distance measurement.
However, in other cases, as a target of distance measurement
It is determined to track. In addition, especially according to the second feature
For example, if the motorcycle is located relatively close to the front of your
If this is the case, add this motorcycle as a target for distance measurement.
Although not tailed, the motorcycle is located relatively far in front of the vehicle.
Vehicle or a truck ahead of you
If there is a vehicle whose vehicle width exceeds a certain value, such as
And track the vehicle as a target for distance measurement.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings.

1 to 7 show an embodiment of the present invention. FIG. 1 is a block diagram showing a configuration of a distance measuring device, and FIG. 2 is an arrangement of an object and a window on a screen of an image sensor. FIG. 3 is a flow chart showing a processing procedure by a microcomputer, FIG. 4 is a view for explaining a distance measuring principle, FIG. 5 is a view for explaining a correlation calculation, and FIG. 6 is for explaining an interrupt state. And FIG. 7 are diagrams for explaining the lane change state.

First, in FIG. 1, this vehicle distance measuring device is obtained by a pair of upper and lower image pickup means 1A and 1B arranged in the vehicle interior of a vehicle, for example, on the rear side of a windshield, and these image pickup means 1A and 1B. Object 4 such as the preceding vehicle
A / D converters 5A and 5B for converting the image signals of the above into digital signals respectively, image storage means 6A and 6B for respectively storing the image information converted into digital signals, and the images stored in the image storage means 6A and 6B. A microcomputer 8 for calculating the distance to the object 4 based on the signal and a memory 9 attached to the microcomputer 8 for storing the distance and the like are provided. Control device 1 for controlling the vehicle
0 is input to the vehicle travel control device 10, and the vehicle travel control device 10 executes control for causing the vehicle to travel, for example, following a preceding vehicle ahead of the vehicle.

Each of the image pickup means 1A and 1B is composed of an optical system 2A and 2B including a lens, and image sensors 3A and 3B arranged behind the optical systems 2A and 2B by a focal length f. And both optical systems 2A, 2B
Are arranged vertically above and below the baseline length BL.

According to such image pickup means 1A and 1B,
An object 4 such as a preceding vehicle existing in front of the own vehicle is an optical system 2
An image is formed on the image sensors 3A and 3B by A and 2B. The image sensors 3A and 3B are, for example, as shown in FIG. 2, a plurality of vertically extending line CCDs 7 and 7, for example. Are one-dimensional image sensors that are arranged laterally at intervals.

The microcomputer 8 displays a plurality of windows W on the screen defined by the image sensors 3A and 3B.
W (determined by the shaded area in FIG. 2) for determining a window, correlation calculation means for performing a correlation calculation for each combination of windows W, W, ... Corresponding to each other on the screen determined by both image sensors 3A, 3B, Distance calculation means for calculating the distance to the object 4 based on the calculation result of the correlation calculation means,
The object 4 is placed in the image area defined by the windows W, W ...
Lane change determining means for determining whether or not a lane change has been made for a vehicle whose distance has been measured when there are a plurality of vehicles, the object 4 is within the image area defined by the windows W, W ... When there is a plurality of certain vehicles, the vehicle that was the object of distance measurement and the interruption determining means that determines whether another vehicle interrupts between the vehicle and the lane change determining means when the lane change is determined. The object switching means functions to change the object of distance measurement to a vehicle other than the lane-changed vehicle and to change the object of distance measurement to an interrupt vehicle when the interrupt determination means determines that the vehicle is an interrupt.

In the microcomputer 8, the processing procedure as shown in FIG. 3 is set, and in step S1,
Image signals corresponding to the respective windows W, W ... Defined as shown in FIG. 2 are cut out from the image storage means 6A, 6B. The cutting out of the windows W, W ... Is for excluding the images of the road, the background, and other objects other than the image of the preceding vehicle, which is the object 4, from the distance calculation.
Then, the distance calculation of the image signal is executed for each combination of the windows W and W corresponding to each other.

In the distance calculation, the correlation calculation for each combination of the windows W and W corresponding to each other is first executed, and as shown in FIG.
It is possible to obtain the shift amount n at the point where the correlations of the brightness data obtained from both the image sensors 3A and 3B are the best. The correlation calculation is performed, for example, by fixing one of the brightness data of windows W corresponding to each other and shifting the other one by one to perform the subtraction. That is, as shown in FIG. 5A, the brightness data on the image sensor 3B side is fixed and the image sensor 3B is fixed.
By subtracting the brightness data on the A side from the brightness data on the image sensor 3B side while shifting the brightness data one by one up and down, a shift amount corresponding to the correlation value can be obtained as shown in FIG. 5B. The shift amount n when the correlation value is the smallest can be obtained as a value corresponding to the shift amount of the image signal from the optical axis. Thus, the shift amount n is the optical system 2 of the image signal obtained from the lower image sensor 3A.
The amount of deviation nA from the optical axis of A and the upper image sensor 3
It is the sum of the amount of deviation nB of the image signal obtained from B from the optical axis of the optical system 2B.

Based on the deviation amount n obtained for each combination of the windows W, W corresponding to each other, each window W,
The distance calculation based on the principle of triangulation is executed for each combination of W, and the distance D to the object 4 is calculated.
_W will be obtained for each combination of windows W and W based on D _W = (BL × f) / n.

In step S3 after obtaining the distance D _W for each combination of the windows W and W in step S2, it is determined whether or not the tracking flag F _P is "1". The tracking flag F _P is “1” when the object 4 existing in front of the vehicle is being tracked, and is “0” when the object 4 is not being tracked, and when F _P = 0. That is, when the non-tracking is being performed, the process proceeds from step S3 to step S4.

In step S4, the distance and direction of the preceding vehicle are determined based on the distance D _{W for} each combination of the windows W and W obtained in step S2, and the temporal continuity of the distance and direction of the preceding vehicle up to the previous time. judge. In the determination of the preceding vehicle, the distance D _W window W adjacent to the each other has a value in the constant and close range, adopting the combination of W, window W where the distance D _W is out of the range,
The combination of W and the combination of windows W and W in which the image has no contrast enough to detect the correlation are excluded. Regarding the temporal continuity, the distance change amount is a fixed value or less continuously for a fixed time. It is determined by. In addition, a condition may be added that the preceding vehicle cannot be determined when the distance to the preceding vehicle cannot be obtained with a certain number or more of the combinations of the windows W and W. It is possible to avoid distance measurement in the state where the vehicle in front of the vehicle is tilted, and it is possible to contribute to improvement of distance measurement performance in situations such as during an interrupt. Furthermore, the direction of the preceding vehicle may be determined based on the distribution of the window W on which the preceding vehicle distance has been obtained, and at this time, as shown in FIG. 2, each of the windows W, W ... If the shape is set to extend vertically, the detection accuracy of the horizontal position can be improved.

In step S5, the possibility of tracking is determined based on the distance of the preceding vehicle obtained in step S4 and the vehicle flag F _V. The vehicle flag F _V is set in step S described later.
It is obtained from the result of executing the vehicle determination in 14, and in the case of a vehicle having a certain width or less such as a motorcycle,
The vehicle flag F _V is "0", and as a result of determining in step S14 whether or not the object 4 in front of the vehicle is a vehicle, the vehicle flag F _V is "0". If the distance obtained in step S4 is equal to or less than a certain value, the tracking is determined not to be performed, but otherwise the tracking is determined to be performed. In other words, if the motorcycle exists at a position relatively close to the front of the vehicle, it does not track,
If the motorcycle exists in a position relatively far ahead of the host vehicle, and when the vehicle in the vehicle width of the passenger vehicles and trucks, etc. in front of the vehicle is more than a predetermined value exists, such a the tracking child < br /> Based on the determination result in step S5, in step S6, the flag F _P is set to “1” when it is determined that the tracking is performed, and the flag F _P is set to “0” when the tracking is not performed.

Step S7 after step S6 has passed
Then, the distance of the preceding vehicle obtained in step S4 is output.

When the flag F _P is "1" in step S3, that is, the motorcycle located at a relatively distant position in front of the host vehicle or the passenger vehicle or truck located in front of the host vehicle is being tracked. If so, the distance of the preceding vehicle is determined in step S8. In determining this distance, the distance D _{W for} each combination of windows W, W ...
The distance determination is executed on the basis of the distance and the direction obtained until then for the preceding vehicle being tracked, and the same process as step S4 described above is performed to determine the distance to the preceding vehicle being tracked.

In step S9, a short-distance object is present on the side closer to the own vehicle than the preceding vehicle by the distance D _W of the combination of the windows W and W other than the combination of the windows W and W that have obtained the distance to the preceding vehicle. It is determined whether to do. That is, the distance to the preceding vehicle is a value that is continuous to the distance obtained until then for the preceding vehicle that is being tracked, and when another object comes in between the vehicle and the preceding vehicle so as to hide the preceding vehicle, The short-distance object is determined by detecting a small distance that is a predetermined value or more from the distance to the preceding vehicle.

When it is confirmed in step S10 that it is determined in step S9 that there is no short-range object, the process proceeds from step S10 to step S7 to output the distance to the preceding vehicle, and in step S9, the short-range object exists. Then, when it is confirmed in step S10 that the determination is made,
The process proceeds from step S10 to step S11.

In step S11, the distance and direction of the short-distance object determined in step S9 are temporarily held, and then lane change is determined in step S12. In this lane change, the distance of the preceding vehicle and the distance of the short-distance object are compared, and both distances are substantially close to each other, and when the vehicle flag F _{V of the} preceding vehicle is “0”, the vehicle is currently being tracked. It is determined that the preceding vehicle has changed lane. This is because the vehicle that the preceding vehicle currently being tracked (current preceding vehicle) has interrupted before is a motorcycle or the like with a vehicle width that is less than a certain width, and the preceding vehicle that existed in front of the vehicle before the interruption. This is because the situation in which (the preceding vehicle) is located relatively close to the own vehicle is detected.

When it is confirmed in step S13 that it is determined that there is no lane change in step S12,
At 14, the vehicle determination is executed. This vehicle determination sets the vehicle flag F _V to “0” in the case of a vehicle having a certain width or less such as a motorcycle, but sets the vehicle flag F _V to “1” in the case of other vehicles. If the current preceding vehicle is a motorcycle or the like and F _V = 0 is confirmed in step S15, the process proceeds to step S7, and if F _V = 1 is confirmed in step S15, step S16 is performed. Proceed to.

In step S16, the interruption judgment is executed based on the distance and the direction of the short-distance object held in step S11. That is, the interruption to the front of the vehicle starts from either the left side or the right side.
Interrupt detection is executed by detecting that a short-distance object moves laterally with a continuous distance value from either the left or right end on the screen determined by A and 3B.

When it is confirmed in step S18 that the interruption has occurred in step S16, the process proceeds to step S18, and the distance of the short-distance object is output in step S18. That is, when it is determined that an interruption has occurred, instead of outputting the distance of the preceding vehicle until then, the distance of the interruption vehicle that is a short-distance object is output.

When it is confirmed in step S13 that a lane change has occurred, the tracking flag F _{P is set} to "0" in step S19, and the process proceeds to step S18. That is, when a lane change occurs, the tracking flag F _{P is set} to "0" in order to execute the processes of steps S3 to S7 again for the vehicle that appears in front of the own vehicle after the lane change (the vehicle that was tracking before the interruption). Set to.

Next, the operation of this embodiment will be described. As shown in FIG. 6, for example, when a motorcycle or the like interrupts between the own vehicle and the preceding vehicle which are stopped due to traffic jam or the like, the windows W, W are provided. A plurality of vehicles, which are the objects 4, are present in the image area defined by ... At this time, the function of the microcomputer 8 as the interrupt determination means (step S16 in FIG. 3) determines the vehicle interrupt, The distance of the interrupting vehicle is replaced by the microcomputer 8 instead of the distance of the preceding vehicle by the function (step S17 of FIG. 3) of the microcomputer 8 as the target switching means.
Is given to the vehicle travel control device 10.

As shown in FIG. 7, when an interrupting vehicle such as a motorcycle (current preceding vehicle) changes lanes, the microcomputer 8 has a function as lane change determining means (step S12 in FIG. 3). A change is determined, and a short-distance object on the side closer to the vehicle than the vehicle whose lane is changed by the function (step S13 in FIG. 3) of the microcomputer 8 as a target switching means, that is, in front of the vehicle before an interruption occurs The distance of the preceding vehicle that was present in the
Is given to the vehicle travel control device 10.

In this way, when the interruption vehicle slips through, the distance of the front vehicle existing in front of the own vehicle after the slipping through is surely measured and the microcomputer 8
Can be input to the vehicle travel control device 10, and the distance of the preceding vehicle that the driver is supposed to be aware of can be smoothly switched and measured according to the occurrence of an interrupt and the lane change of the interrupted vehicle.

In the above embodiment, it is difficult for a vehicle having a certain vehicle width or more to interrupt, but a vehicle with a narrow vehicle width such as a motorcycle can be interrupted by a distance between the vehicle and the preceding vehicle. Although the case where the traveling control of the vehicle following the preceding vehicle is performed is described, the vehicle having a certain width or more can be interrupted between the own vehicle and the preceding vehicle. It is not necessary to include the condition that the vehicle flag F _V is “0” in the lane change determination condition, and it is not essential that the vehicle flag F _V be “0” for the interrupt determination in step S16. The interrupt determination may be performed in parallel with the lane change determination.

In the above embodiment, the correlation calculation is executed by the microcomputer 8. However, the correlation calculation may be executed by a dedicated calculation circuit such as a gate array to speed up the calculation. The distance may be provided as an inter-vehicle distance warning device, or the dangerous inter-vehicle distance determination means and the alarm device may be added to the microcomputer 8 to use the measured distance as the inter-vehicle distance warning device.
Further, as the image sensors 3A and 3B, a two-dimensional image sensor in which a large number of pixels are dispersed and arranged on a plane may be used.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the claims. It is possible to do.

[0034]

As described above, according to the present invention, it is possible to measure the distance of the interrupting vehicle that is interrupted between the own vehicle and the preceding vehicle, and the interrupting vehicle exists in front of the interrupting vehicle due to the lane change. When passing through the side of another preceding vehicle, it is possible to switch the vehicle whose distance is to be measured from the passing interrupted vehicle to another preceding vehicle existing in front of the own vehicle, generating an interrupt and changing the lane of the interrupting vehicle. Accordingly, the distance of the preceding vehicle that the driver is supposed to be aware of can be smoothly switched and measured.

Further , according to the invention of claim 1, in particular,
An object in front of a vehicle with a certain width or less, such as a motorcycle,
And if the distance to the object is less than a certain value
Is determined not to track as a target of distance measurement,
In other cases, it is determined that the object will be tracked as a target for distance measurement.
Is determined.

Further , according to the invention of claim 2, in particular,
If the motorcycle is relatively close to the front,
Does not track this motorcycle as a target for distance measurement
However, there is a motorcycle at a relatively distant position in front of the vehicle.
The width of the passenger vehicle or truck, etc.
If there are vehicles whose
Track as an object of distance measurement.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a distance measuring device.

FIG. 2 is a diagram showing an arrangement of an object and a window on a screen of an image sensor.

FIG. 3 is a flowchart showing a processing procedure by a microcomputer.

FIG. 4 is a diagram for explaining the principle of distance measurement.

FIG. 5 is a diagram for explaining a correlation calculation.

FIG. 6 is a diagram for explaining an interrupt state.

FIG. 7 is a diagram for explaining a lane change state.

[Explanation of symbols]

2A, 2B ... Optical systems 3A, 3B ... Image sensor 4 ... Object 8 ... Microcomputer W having functions of lane change determination means, interrupt determination means, and target switching means ...

Continuation of front page (51) Int.Cl. ⁷ Identification code FI H04N 7/18 H04N 7/18 J (72) Inventor Kazuto Chisaka 1-4-1 Chuo, Wako-shi, Saitama, Ltd. 56) References JP-A-6-265351 (JP, A) JP-A-6-249652 (JP, A) JP-A-6-249653 (JP, A) JP-A-5-106475 (JP, A) JP Flat 4-269617 (JP, A) JP-A-6-255391 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60R 21/00 G01C 3/06 G08G 1/16 H04N 7 / 18

Claims (2)

(57) [Claims] 1. Comparing image signals in a window (W) of a pair of images formed on an image sensor (3A, 3B) by a pair of optical systems (2A, 2B) and comparing them from the optical axis of both images. In the vehicle distance measuring device for electrically detecting the deviation amount of the object and performing a calculation based on the principle of triangulation using the deviation amount to measure the distance to the object (4). Object in the image area defined by (4)
Lane change determining means (8) for determining whether or not a lane change of the vehicle that has been the object of distance measurement occurs when there are a plurality of vehicles, and an object within the image area defined by the window (W). Thing (4)
When there are a plurality of vehicles, the interrupt determination means (8) for determining whether or not another vehicle has interrupted between the vehicle that was the object of distance measurement and the own vehicle, and the lane change determination means (8). When it is determined that the change is made, the distance measurement target is changed to a vehicle other than the lane-changed vehicle, and when the interrupt determination means (8) is determined to be an interruption, the distance measurement target is changed to the interrupted vehicle. (8) and a, the subject switching means (8), the object in front of the vehicle
If (4) is a vehicle of a certain width or less, such as a motorcycle, and
When the distance to the target object (4) is less than a certain value,
Although it is determined that tracking is not performed as a target for distance measurement,
A vehicle distance measuring device, characterized in that it is determined to be tracked as an object of distance measurement when outside . 2. Imaged by a pair of optical systems (2A, 2B)
A pair of images formed on the image sensor (3A, 3B)
Optical signals of both images by comparing the image signals in the window (W)
Based on the principle of triangulation.
To the object (4) by executing the calculation using the deviation amount
In a vehicle distance measuring device that measures the distance of The object (4) within the image area defined by the window (W)
Is the target of distance measurement when there are multiple vehicles.
To determine whether the lane of the vehicle has changed Lane change
Further judging means (8), The object (4) within the image area defined by the window (W)
Is the target of distance measurement when there are multiple vehicles.
Judging whether or not another vehicle has interrupted between the vehicle and its own vehicle
Interrupt determination means (8) for When the lane change determination means (8) determines that the lane has changed
If the target of distance measurement is changed to a vehicle other than the lane changing vehicle
Both were judged to be interrupts by the interrupt judgment means (8).
Sometimes switching the target of distance measurement to an interrupted vehicle
And means (8), The target switching means (8) is located relatively close to the front of the vehicle.
If there is a motorcycle in the
Although not tracked, the motorcycle is located relatively far in front of the vehicle.
If a car is present, or in front of you,
If there is a vehicle whose width exceeds a certain value, such as
Vehicle distance, characterized by tracking as an object of measurement
Distance measuring device.