JP3324859B2 - Inter-vehicle distance control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance control device for automatically maintaining a constant inter-vehicle distance with a preceding vehicle during a traffic jam or the like.

[0002]

2. Description of the Related Art In general, when driving a vehicle such as an automobile, if the distance between the vehicle and a preceding vehicle becomes short due to traffic congestion or the like, the driver frequently operates an accelerator pedal or a brake to start / stop the vehicle. You have to repeat. If such a situation lasts for a long time, a heavy burden is imposed on the driver, and mental and physical fatigue occurs, which is not preferable in terms of safety.

[0003] For this reason, recently, a vehicle, a camera, an ultrasonic sensor or the like is mounted on a vehicle to detect a preceding vehicle, and an automatic control mechanism attached to a throttle valve or a brake of an engine is used to control a driver in a traffic jam or the like. There has been proposed a device that attempts to reduce the burden on the driver by partially automating it.

For example, Japanese Unexamined Patent Publication No. 2-95931 discloses that if a driver does not depress a brake during traffic congestion or the like, a predetermined vehicle speed is set by a computer unit regardless of the amount of depression of an accelerator pedal. A device is disclosed in which a throttle valve driving device is driven to control a throttle valve, and when a person or a vehicle approaches forward, a brake is automatically activated to stop the vehicle.

[0005]

However, in the conventional device, the brakes are automatically operated only in an emergency when there is a danger of a collision with a preceding vehicle. Only automatically
Since the operation of the brake must be performed by the driver, the burden on the driver cannot be sufficiently reduced.

Further, under actual traffic jam conditions, the traveling speed of the entire flow is constantly changing, and in the conventional device for controlling the throttle opening of the engine so that the vehicle speed becomes a predetermined value. It is either too fast or too slow for the preceding vehicle, making it difficult to respond.

The present invention has been made in view of the above circumstances, and releases a driver from frequent operations of an accelerator or a brake, and automatically reduces a burden on the driver by maintaining a constant inter-vehicle distance with a preceding vehicle. It is another object of the present invention to provide an inter-vehicle distance control device capable of improving safety.

[0008]

SUMMARY OF THE INVENTION The present invention detects a preceding vehicle existing in the traveling direction of a subject vehicle and calculates a distance between the preceding vehicle and the subject vehicle and a relative speed of the preceding vehicle with respect to the subject vehicle. Release means and throttle valve of the engine.
First control for speed control by driving with a tutor
Drive the device and the parking brake with an actuator
A second control device that performs deceleration control and stop control by
A target inter-vehicle distance is set based on the speed of the own vehicle, and any of the first and second control devices is determined based on the inter-vehicle distance and the relative speed calculated by the preceding vehicle detecting means.
Select the distance between the vehicle and the preceding vehicle
While maintaining the following distance control and keeping the speed below the desired speed.
When the throttle of the first control device is fully closed.
Deceleration control or stop control is deemed necessary
When performing control using the second control device.
It is characterized by.

[0009]

[0010]

[0011]

[0012]

According to the present invention, the throttle valve of the engine is opened.
The first control that controls the speed by driving with a actuator
Control device and parking brake driven by actuator
Control device that performs deceleration control and stop control by performing
The distance between the preceding vehicle and the own vehicle is determined by the speed of the own vehicle.
Distance control to keep at the target distance set based on the vehicle
Is calculated based on the following distance and the relative speed between the preceding vehicle and the own vehicle.
And any one of the second control device is selected and performed.
When below the desired speed, the throttle of the first control device
When fully closed, deceleration control or stop control
When it is determined necessary, control is performed using the second control device.
I do.

[0013]

[0014]

[0015]

[0016]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 40 relate to a first embodiment of the present invention, FIG. 1 is an overall configuration diagram of an inter-vehicle distance control device, FIG. 2 is a circuit block diagram of the inter-vehicle distance control device, and FIG. 3 is a configuration around a parking brake actuator. FIG. 4 is an explanatory diagram showing a screen of a display, FIG. 5 is an explanatory diagram showing an appearance of another display unit, FIG. 6 is a front view of a vehicle, and FIG. 7 is an explanatory diagram showing a relationship between a camera and a subject. 8, FIG. 8 is a detailed circuit diagram of the image processor, FIG. 9 is an explanatory diagram of a city block distance calculating circuit, FIG. 10 is a block diagram of a minimum value detecting circuit, and FIG. 11 is an example of an image captured by a vehicle-mounted CCD camera. FIG. 12 is an explanatory view showing an example of a distance image.
3 is a top view of the vehicle, FIG. 14 is a side view of the vehicle, FIG. 15 is a functional block diagram of an image processing / inter-vehicle distance control computer, FIG. 16 is an explanatory diagram showing an example of a road model, and FIG.
FIG. 18 is an explanatory diagram showing the shape of a two-dimensional window, FIG. 19 is an explanatory diagram showing a deviation between a linear element and data, and FIG. 20 is an explanatory diagram showing the relationship between the deviation and a weighting factor. FIG. 21 is an explanatory diagram showing an example of the detected road shape, FIG. 22 is an explanatory diagram showing a method of dividing the image, and FIG.
3 is an explanatory diagram showing the relationship between the detected object and the histogram, FIG.
4 is an explanatory diagram showing an example of a detection result and a detection distance of a region where an object exists, FIG. 25 is an explanatory diagram showing a shape of a three-dimensional window for object detection, and FIG. 26 is a diagram showing a shape of a two-dimensional window for object detection. FIG. 27 is an explanatory view showing an example of data constituting an outline of an object, FIG. 28 is an explanatory view showing an example of an outline image of an object and detected outer diameter dimensions, and FIG. 29 is a concept of determining a throttle opening. FIG. 30 is a flowchart showing the operation of the image processor, FIG. 31 is an explanatory diagram showing the storage order in the shift register, FIG. 32 is a timing chart showing the operation of the city block distance calculation circuit, and FIG. FIG. 34 is a timing chart showing the operation of the unit.
Is a timing chart showing the operation of the image processor, FIGS. 35 and 36 are flowcharts of road detection processing, FIGS. 37 and 38 are flowcharts of object detection processing, FIG. 39 is a flowchart of throttle control processing, and FIG. 40 is parking brake control processing. It is a flowchart of FIG.

In FIG. 1, reference numeral 1 denotes a vehicle such as an automobile, and an inter-vehicle distance control device 300 mounted on the vehicle 1
A stereo optical system that realizes a function as a preceding vehicle detecting unit that detects a preceding vehicle existing in the traveling direction of the own vehicle and calculates a distance between the preceding vehicle and the own vehicle and a relative speed of the preceding vehicle to the own vehicle. A system 10 and an image processing unit 100 are provided .
Speed is controlled by driving the throttle valve with an actuator.
Control device for performing degree control, and parking brake
Deceleration control and stop by driving key with actuator
Inter-vehicle distance control that realizes the function of a second control device that performs control
The control unit 200 is connected. This inter-vehicle distance control
The unit 200 sets a target inter-vehicle distance based on the speed of the own vehicle, and selects one of the first and second control devices from the inter-vehicle distance and the relative speed calculated by the preceding vehicle detecting means.
The distance between vehicles that keeps the distance to the preceding vehicle at the target distance
While performing distance control, when the speed is equal to or less than a desired speed, the first
When the throttle of the control unit is fully closed, decelerate
When it is determined that control or stop control is necessary,
Is controlled by using the control device.

The stereo optical system 10 includes a pair of left and right cameras as an image pickup system for picking up an object outside the vehicle. In the image processing unit 100 to which the pair of right and left cameras is connected, the stereo optical system 10 is used. 10 is processed to calculate a three-dimensional distance distribution over the entire image by processing a pair of left and right stereo images captured by 10. From the distance distribution information,
A road shape and three-dimensional positions of a plurality of three-dimensional objects are detected at high speed. Then, the preceding vehicle is identified by comparing the detected road shape with the position of each three-dimensional object, and the inter-vehicle distance and relative speed with respect to the preceding vehicle are determined based on a signal from the vehicle speed sensor 8. Output to

The inter-vehicle distance control unit 200 is connected in parallel with a throttle actuator 3 for controlling the opening of a throttle valve 2 of an engine (not shown) and a parking brake handle (hand brake) 4. A parking brake actuator 6 for activating the parking brake 5 in response to a signal from the inter-vehicle distance control unit 200, and a changeover switch 7 provided in the vehicle compartment for the driver to activate and deactivate the device.
When the vehicle speed sensor 8, a display 9 which is installed in front of the driver in order to notify the control state of the host vehicle to the driver are connected, the active drive assist to perform advanced assist control to the driver One function of the (ADA) system is to automatically maintain a constant inter-vehicle distance with a preceding vehicle during traffic congestion, etc., thereby reducing the burden on the driver and ensuring safety.

Note that, when the vehicle speed of the own vehicle 1 is equal to or higher than a set value (for example, 20 km / h), the present device does not operate even if the driver turns on the changeover switch 7. Also, when the driver operates the main brake pedal or the accelerator pedal while the present device is operating, the operation of the present device is released.

The inter-vehicle distance control unit 200 sets an appropriate inter-vehicle distance target value based on the traveling speed of the own vehicle obtained from the vehicle speed sensor 8, and the image processing unit 10
The start, acceleration, deceleration, stop, etc. of the own vehicle 1 are determined from the inter-vehicle distance and the relative speed with respect to the preceding vehicle calculated at 0, and corresponding signals are output to the throttle actuator 3 and the parking brake actuator 6.

As a result, the throttle actuator 3, which is operated by a servo motor or air pressure, is driven to control the opening of the throttle valve 2, and the engine output is adjusted to control the starting and speed. Further, the parking brake actuator 6 is driven, and the parking brake 5 is controlled via a wire coupler 13 that connects the parking brake handle 4 and the parking brake actuator 6 in parallel.

The parking brake actuator 6
As shown in FIG. 3, for example, an electric motor 14 and a worm gear 15 rotated by the electric motor 14
One end of an arm 16 is attached to the center of the worm wheel of the worm gear 15, and a wire cable 6a is attached to the other end of the arm 16. Two limit switches 17a and 17 are provided on the outer periphery of the worm wheel of the worm gear 15 to detect the rotational position of the arm 16 and regulate the rotation range.
b is installed facing.

A wire cable 6a attached to the arm 16 and a wire cable 4a extending from the parking brake handle 4 are provided on one side of the wire coupler 13 with long holes 13a, 1a, respectively.
3b and the wire coupler 1
3, a wire cable 5a connected to the parking brake 5 is locked. When the wire cable 5a is indexed from either the parking brake handle 4 or the parking brake actuator 6, the wire coupler 13 is disconnected. The wire cable 5a is indexed through
The parking brake 5 is operated.

In this case, the parking brake actuator 6 performs an ON / OFF operation. When the parking brake actuator 6 is turned on, the electric motor 14 rotates, and the arm 16 connected to the worm gear 15 rotates to move the wire. Pull the cable 6a. When the arm 16 reaches the position of the limit switch 17a, the limit switch 17a is turned on, and the electric motor 1
4 stops, the wire cable 6a is kept pulled, and the parking brake 5 is maintained in the operating state.

When the parking brake actuator 6 is turned off, the electric motor 14
Is rotated until the position of (1) reaches the position of the limit switch 17b, and the parking brake 5 is released with no tension on the wire cable 6a.

In the braking of the vehicle 1 by the parking brake 5, there is a limit to the deceleration that can be generated.
When the preceding vehicle applies sudden braking, there is a possibility that the preceding vehicle abnormally approaches. Therefore, the inter-vehicle distance control unit 200 presumes such a situation and displays it on the display 9 to warn the driver, thereby urging the driver to operate a main brake (not shown).

As shown in FIG. 4, a monitor 9a for displaying the scenery ahead of the vehicle in a state of a distance image, which will be described later, is provided at the center of the screen of the display 9. On the side, each mode of ADA (for example,
A cruise mode that automatically and properly controls the distance to the preceding vehicle when driving at a constant speed on a highway, a guide mode that displays the left and right gaps between the object existing on the left and right ahead and the side of the vehicle, traffic jams A mode display section 9b for displaying a traffic jam mode for automatically appropriately controlling the inter-vehicle distance to a preceding vehicle, an assist mode for warning a danger of collision with an obstacle, etc.
When a prescribed signal is input from the changeover switch 7, when the vehicle speed is equal to or less than a set vehicle speed during traffic congestion or the like, a congestion mode for controlling an inter-vehicle distance with a preceding vehicle is selected, and the mode display portion 9b is displayed. The corresponding "traffic jam" display is turned on.

A data display section 9c and a position display section 9d representing the front, rear, left and right of the vehicle in a shape obtained by dividing an ellipse into four parts are provided above the monitor section 9a. A mode data display section 9e for displaying characters and numerical values in each mode of the ADA is provided. When the congestion mode is selected, the calculated numerical values are displayed below the characters of the following distance and the speed as shown in FIG. Then, the front and rear portions of the position display section 9d are turned on. This position display section 9d
Is normally illuminated in green, and is illuminated, for example, in red when there is a possibility of abnormally approaching the preceding vehicle. Thus, a warning is given to the driver to urge the driver to perform the brake operation.

For simplicity, the display 9 may be replaced with a display 18 having a changeover switch SW and lamps LP1 to LP5 disposed on the front face as shown in FIG. The display 18 turns on the lamp LP1 when no preceding vehicle is detected, and turns on the lamp LP2 when the throttle actuator 3 is operating. Further, when the throttle actuator 3 is in the fully-closed throttle operation and the parking brake actuator 6 is OFF, the lamp LP3 is turned on,
The lamp LP4 is turned on while the parking brake actuator 6 is operating. Further, there is a possibility that the vehicle may abnormally approach the preceding vehicle, and the lamp LP5 is turned on in a state where an alarm is generated. Instead of distinguishing the contents displayed by the plurality of lamps LP1 to LP5 in this manner, a lamp capable of displaying a plurality of colors may be attached, and the displayed contents may be distinguished by the colors of the lamps. Instead, a warning by a sound such as a buzzer or a warning by sound may be used.

As described above, according to the present apparatus, the driver can be released from the repetition of the complicated brake and accelerator operations in the sloppy driving during traffic jams and the like, and the burden on the driver can be greatly reduced. Is always displayed on the display 9 and the possibility of abnormal approach to the preceding vehicle is estimated in advance and an alarm is issued. Therefore, it is possible to give a sufficient time margin to the driver's driving operation to enhance safety. it can. Also, even in the event of a trouble, the driver can easily grasp the situation and can perform a quick response operation.

Further, in this device, since the parking brake is used for stopping and decelerating the vehicle, it can be easily applied to an existing vehicle, the cost can be minimized, and high reliability can be secured. is there.

Next, the hardware configuration of the image processing unit 100 and the following distance control unit 200 will be described.

The stereo optical system 10 connected to the image processing unit 100 includes, for example, a charge-coupled device (CC)
D), and a pair of left and right CCD cameras 11a and 11b for a long distance and a pair of right and left CCD cameras for a short distance as described later. Cameras 12a and 12b are provided.

The image processing unit 100 and the inter-vehicle distance control unit 200 specifically process an image captured by the stereo optical system 10 and output distance distribution data (distance image) in the form of an image. And an image processing / inter-vehicle distance control computer 110 for performing processing for detecting a preceding vehicle from the distance image from the image processor 20 and controlling the inter-vehicle distance to be constant.

The image processor 20 searches the two stereo image pairs picked up by the stereo optical system 10 for a portion where the same object is shown for each minute area,
A distance detection circuit 20a for calculating a distance to an object by obtaining a shift amount of a corresponding position; and the distance detection circuit 20a
The image processing / inter-vehicle distance control computer 110 comprises a distance image memory 20b for storing distance distribution data which is an output of the microcomputer. The microprocessor 110a mainly performs processing for detecting a road shape, and mainly detects individual three-dimensional objects. 110 that performs processing
b and a microprocessor 110c that mainly performs processing for controlling the inter-vehicle distance to the preceding vehicle
And a system configuration of a multi-microprocessor connected in parallel via the.

The system bus 111 has an interface circuit 112 connected to the distance image memory 20b and a ROM 113 for storing a control program.
And a RAM 1 for storing various parameters during calculation processing
14, an output memory 115 for storing processing result parameters, and a display controller (DISP.CON) for controlling the display (DISP) 9.
T. ) 116 and signals from sensor switches such as the changeover switch 7, the vehicle speed sensor 8, and a steering angle sensor 19 for detecting a steering angle of steering.
An input / output (I / O) interface circuit 117 for outputting control signals to actuators such as the throttle actuator 3 and the parking brake actuator 6.
And are connected.

In the image processing / inter-vehicle distance control computer 110, each microprocessor 110a,
The areas of the memory used by 110b and 110c are divided, and the microprocessors 110a and 110b execute a road shape detection process and a three-dimensional object detection process based on the distance information from the image processor 20, and detect the detected road shape. And data such as the position of each three-dimensional object, the inter-vehicle distance to the preceding vehicle, and the relative speed are output to the output memory 115.

The data stored in the output memory 115 is read by the microprocessor 110c,
The throttle actuator 3 and the parking brake actuator 6 are used to keep the distance between the vehicle and the preceding vehicle constant.
And a process of estimating in advance the possibility of abnormally approaching the preceding vehicle and issuing an alarm.

The functions of the image processor 20 and the image processing / inter-vehicle distance control computer 110 will be described below.

The left and right 1 constituting the stereo optical system 10
As shown in FIG. 6, the pair of cameras includes two CCD cameras 11a and 11b (which may be represented as CCD cameras 11) for long-distance left and right images, respectively. Are mounted at regular intervals, and two CCD cameras 12a and 12b for the left and right images at a short distance (which may be represented by the CCD camera 12 as a representative) are respectively CCD cameras 11a for a long distance. , 11b are attached at regular intervals.

When the stereo optical system 10 measures a distance from the nearest to a distance of, for example, 100 m, if the mounting positions of the CCD cameras 11 and 12 in the vehicle compartment are, for example, 2 m from the end of the hood of the vehicle 1, actually Should be able to measure the position from 2 m to 100 m in front.

Therefore, the short distance CCD camera 12a,
In 12b, the position from 2m to 20m in front is measured,
In the long distance CCD cameras 11a and 11b,
If you measure the position from m to 100m, it will be CC for short distance
D camera 12 and long distance camera 11 from 10m ahead 2
While ensuring reliability with an overlap between 0m,
All ranges can be measured.

In this embodiment, in order to detect a relatively short-distance preceding vehicle at a low speed such as in a traffic jam, a long-distance CC is used.
Data from the D camera 11 and the CCD camera 12 for short distance
Is appropriately selected and used.

Hereinafter, the calculation of the distance by the image processor 20 will be described using the long-distance CCD camera 11 as an example. The distance is also calculated for the short-distance CCD camera 12 by the same processing.

That is, as shown in FIG. 7, a point P at a distance D from the installation surface of the two cameras 11a and 11b is photographed, where r is an attachment interval between the two long distance CCD cameras 11a and 11b. The two cameras 11a and 11b
If both the focal lengths of the cameras are f, the image of the point P is projected on the projection plane separated by f from the focal position for each camera.

At this time, the distance from the position of the image on the right CCD camera 11b to the position of the image on the left CCD camera 11a is r + x, and if x is a shift amount, the distance D to the point P is shifted. It can be obtained from the quantity x by the following equation.

D = r × f / x (1) The shift amount x between the left and right images is obtained by extracting some feature such as an edge, a line segment, or a special shape, and finding a portion where the feature matches. Can be detected, but in order to avoid a decrease in the amount of information,
When finding the image of the same object in the left and right images, the image is divided into small regions, and the brightness or color pattern in each small region is compared with the left and right images to find the corresponding region, so that the distance for each small region Find the distribution over the entire screen.

The evaluation of the degree of coincidence of the left and right images, that is, stereo matching, is as follows. Assuming that the luminance (color may be used) of the i-th pixel of the right image and the left image is Ai and Bi, respectively, )), And when the minimum value of the city block distance H between the small areas of the left and right images satisfies a predetermined condition, it can be determined that the small areas correspond to each other.

H = Σ | Ai−Bi | (2) In the stereo matching based on the city block distance H, the information amount does not decrease due to the subtraction of the average value.
Although there is no multiplication, the calculation speed can be improved.However, if the size of the small area to be divided is too large, the possibility that a distant object and a nearby object are mixed in the area increases, and the detection is performed. The distance becomes ambiguous. Therefore, to obtain the distance distribution of the image, the smaller the area, the better. However, if the area is too small, the amount of information for checking the degree of coincidence will be insufficient. Therefore, for example, a vehicle with a width of 1.7 m 100 m ahead,
If the number of pixels divided into four is set to the maximum value of the area width so as not to be included in the same area as the vehicle in the adjacent lane, there are four pixels for the stereo optical system 10. As a result of trying the optimum number of pixels on an actual image based on this value, the number of pixels becomes 4 in both the vertical and horizontal directions.

In the following description, it is assumed that the image is divided into small areas of 4.times.4 pixels to check the degree of coincidence between the left and right images. The stereo optical system 10 includes a long-distance CCD camera 11a, 1
1b.

The details of the circuit of the image processor 20 are shown in FIG.
An image conversion unit 30 for converting an analog image captured by the stereo optical system 10 into a digital image, and a city block distance H for determining a shift amount x between left and right images with respect to the image data from the image conversion unit 30. Is calculated one after another while shifting the pixels one by one, a minimum / maximum value detector 50 for detecting the minimum value HMIN and the maximum value HMAX of the city block distance H,
It is checked whether or not the minimum value HMIN obtained by the maximum value detection unit 50 indicates the coincidence of the left and right small areas, and the deviation x
Is provided, and a shift amount determination unit 60 for determining
Dual port memory 90 as distance image memory 20b
Has been adopted.

In the image conversion section 30, C for left and right images
A / D converters 31a and 31b are provided corresponding to the CD cameras 11a and 11b, respectively.
Look-up tables (LUTs) 32a and 32b as data tables, and the CCD camera 1
Image memory 33 for storing images captured in 1a and 11b
a and 33b are connected respectively. The image memories 33a and 33b can be composed of relatively low-speed memories because the city block distance calculation unit 40 repeatedly extracts and processes a part of the image, as described later, thereby reducing costs. be able to.

Each of the A / D converters 31a and 31b has a resolution of, for example, 8 bits,
The analog image from a and 11b is converted into a digital image having a predetermined luminance gradation. That is, if binarization of an image is performed to speed up processing, information for calculating the degree of coincidence between the left and right images is significantly lost.
It is converted to a gray scale of gradation.

The LUTs 32a and 32b are formed on a ROM. The LUTs 32a and 32b increase the contrast of the low-brightness portion of the image converted into digital amounts by the A / D converters 31a and 31b, and the left and right CCD cameras 11a and 11b. To correct the difference in characteristics. And the LUTs 32a and 32b
Are converted into image memories 33a and 33b once.
Is stored.

In the city block distance calculating section 40,
In the image memory 33a for the left image of the image conversion unit 30,
Two sets of input buffer memories 41 via a common bus 80
a and 41b are connected, and two sets of input buffer memories 42a and 42b are connected to the image memory 33b for the right image via the common bus 80.

Each input buffer memory 41 for the left image
Two sets of, for example, eight-stage shift registers 43a, 43b are connected to the input buffer memories 42a, 42b for the right image.
Shift registers 44a and 44b having a stage configuration are connected. Further, these four sets of shift registers 43a, 43
A city block distance calculation circuit 45 for calculating a city block distance is connected to b, 44a, and 44b.

The right image shift register 44
a and 44b include two sets of ones of the shift amount determination unit 60 described later.
The shift registers 64a and 64b having a zero-stage configuration are connected, and when the data transfer of the next small area starts, the old data for which the calculation of the city block distance H has been completed is sent to the shift registers 64a and 64b and shifted. Used in determining the quantity x.

The city block distance calculation circuit 45
9 combines a high-speed CMOS type arithmetic unit 46 which is made into one chip by connecting an input / output latch to an adder / subtracter.
As shown in detail in FIG. 2, a pipeline structure in which 16 arithmetic units 46 are connected in a pyramid shape is used, for example, to simultaneously input eight pixels and calculate. The first stage of the pyramid structure has an absolute value arithmetic unit, the second to fourth stages constitute a first adder, a second adder, and a third adder, respectively, and the last stage is a sum adder. . In FIG. 8, only half of the absolute value calculation and the first and second adders are shown.

Each of the input buffer memories 41a, 41a,
41b, 42a, and 42b are relatively small-capacity high-speed types corresponding to the speed of calculating the city block distance. The inputs and outputs are separated and generated by the # 1 address controller 86 in accordance with the clock supplied from the clock generation circuit 85. Address is given in common. The transfer to and from the four sets of shift registers 43a, 43b, 44a, 44b is controlled by a # 2 address controller 87.

The minimum / maximum value detecting section 50 includes a minimum value detecting circuit 51 for detecting the minimum value HMIN of the city block distance H and a maximum value detecting circuit 52 for detecting the maximum value HMAX of the city block distance H. In this configuration, two high-speed CMOS type arithmetic units similar to the city block distance calculation circuit 45 are used for detecting the minimum value and the maximum value, so that the output of the city block distance H is synchronized. ing.

As shown in FIG. 10, the minimum value detecting circuit 51
Specifically, the A register 46a and the B register 46
b and an arithmetic unit 46 comprising an arithmetic and logic operation unit (ALU) 46c connected to a C latch 53, a latch 54, and a D latch 55. The output from the city block distance calculation circuit 45 is supplied to an A register 46a. And C latch 5
3 and the ALU 46b.
The most significant bit (MSB) of the output of c is output to latch 54. The output of the latch 54 is output to the B register 46b and the D latch 55, and the value in the middle of the calculation of the minimum value in the arithmetic unit 46 is stored in the B register 46b. 55. In addition, regarding the maximum value detection circuit 52,
The configuration is the same as that of the minimum value detection circuit 51 except that the logic is reversed and the deviation amount δ is not preserved.

As described above, the city block distance H is
With respect to one right image small area, the calculation is sequentially performed while shifting the left image small area by one pixel. Therefore, each time the value of the city block distance H is output, the value is compared with the maximum value HMAX and the minimum value HMIN of the previous values, and updated.
Almost simultaneously with the output of the last city block distance H, the maximum value HMAX of the city block distance H in the small area,
The minimum value HMIN is determined.

The shift amount determining unit 60 is configured as a relatively small-scale RISC processor, and has two 16-bit data buses 62 a and 62
b, a latch 63a for holding a shift amount x, a latch 63b for holding a threshold value HA as a first specified value, a latch 63c for holding a threshold value HB as a second specified value, and a third specified value Latch 63 holding the threshold value HC as a threshold value
d, two sets of shift registers 64a and 64b that hold the luminance data of the right image, and the shift amount x
Or a switch circuit 65 for outputting "0", and an output buffer memory 66a for temporarily storing the output result.
66b, a 16-bit width ROM 67 in which a control program of the operation timing of the circuit and the function of the arithmetic unit 61 is written
Is provided.

The arithmetic unit 61 has an A register 71, a B register 72, an F register 7
3 and a selector 74, and the data bus 62
a (hereinafter referred to as A bus 62a), an A register 71 is connected, and the data bus 62b (hereinafter referred to as B bus 62b) is connected to a B register 72.
The switch circuit 65 is operated according to the calculation result of 70, and the shift amount x or "0" is stored in the output buffer memories 66a and 66.
6b.

Each of the threshold values HA,
Latches 63b, 63c, 63d for holding HB and HC and the maximum value detection circuit 52 are connected, and the minimum value detection circuit 51 is connected to the B bus 62b. Further, the shift registers 64a and 64b are connected to the A bus 62a and the B bus 62b.

The computing circuit 61 is connected to the switch circuit 65, and the minimum value detecting circuit 51 is connected to the switching circuit 65 via the latch 63a. The output to the output buffer memories 66a and 66b is switched according to the determination result.

The shift amount determining section 60 checks whether or not the obtained minimum value HMIN of the city block distance H really indicates the coincidence of the left and right small areas. 66a, 66b
Is output to the position of the pixel corresponding to.

That is, the displacement amount at which the city block distance H is the minimum is the displacement amount x to be obtained. If the following three check conditions are satisfied, the displacement amount x is output. Output "0" without using data.

(1) HMIN ≦ HA (The distance cannot be detected when HMIN> HA.) (2) HMAX−HMIN ≧ HB (It is clear that the obtained minimum value HMIN is clearly lower than the fluctuation due to noise. This is a condition for checking. By detecting not the difference from the value near the minimum value HMIN but the difference from the maximum value HMAX, the distance can be detected even for an object such as a curved surface whose brightness changes slowly. (3) Luminance difference between adjacent pixels in the horizontal direction in the small area of the right image> HC (When the threshold value HC is increased, edge detection is performed, but when the luminance changes slowly, The threshold value HC is much lower than the normal edge detection level, which is based on the basic principle that distance detection cannot be performed in a portion where there is no change in luminance. , For each pixel in a small area Therefore, only the pixels for which the distance is actually detected are used in the small area, and a natural result is obtained.) The distance distribution information which is the final result output from the shift amount determination unit 60 Is written to the dual port memory 90 as the distance image memory 20b via the common bus 80.

The distance distribution information output from the image processor 20 is in the form of an image (distance image), and an image captured by the CCD camera 11, for example, as shown in FIG. When the captured image (FIG. 11 shows an image captured by one camera) is processed by the image processor 20, an image as shown in FIG. 12 is obtained.

In the example of the distance image shown in FIG. 12, the image size is 400 pixels horizontally × 200 pixels vertically, and the portion having the distance data is a black dot portion, which is one of the pixels of the image shown in FIG. This is a portion where the change in brightness is large between pixels adjacent in the left-right direction. As shown in FIG. 12, the coordinate system on the image has an origin at the upper left corner and an i coordinate axis in the horizontal direction and j in the vertical direction.
The coordinate axis is used, and the unit is a pixel.

This distance image is read into the image processing / inter-vehicle distance control computer 110, and a plurality of objects such as other vehicles and obstacles present ahead are detected, and the position, size, and time change of the position are detected. , A relative speed with respect to the own vehicle is calculated, and a contour image of the detected object is extracted.

In this case, the image processing / inter-vehicle distance control computer 110 uses the three-dimensional position information of the object to distinguish between the road and the object based on the height from the road surface, and to distinguish between the object and the background. Is performed according to the value of the distance.
Therefore, the image processing / inter-vehicle distance control computer 110 first converts the coordinate system of the distance image from the image processor 20 into a coordinate system of a real space surrounding the own vehicle (vehicle 1), and detects the detected three-dimensional object. Then, the position and size are calculated.

That is, as shown in FIGS. 13 and 14, the coordinate system in the real space is a fixed coordinate system of the vehicle 1, the X axis is on the right side of the vehicle 1, the Y axis is above the vehicle 1, and the Z axis is Vehicle 1
In front of the camera, the origin is set to two CCD cameras 11a (12b),
Assuming that the road surface is just below the center of 11b (12b), XZ
When the road is flat, the plane (Y = 0) coincides with the road surface, and the three-dimensional position (X, Y, Z) of the subject is calculated from the distance information (i, j, Z) in the image. To do so, a kind of coordinate transformation is performed by the following equations (3) and (4).

Y = CH−Z × PW × (j−JV) (3) X = r / 2 + Z × PW × (i−IV) (4) where CH: CCD camera 11 (CCD camera 12) , PW: viewing angle per pixel, JV, IV: coordinates of an infinity point in front of the vehicle 1 on the image.

Also, the three-dimensional coordinates (X, Y, Z) of the real space
The equation for calculating the position (i, j) on the image from the above equation is also obtained by modifying the equations (3) and (4).

J = (CH−Y) / (Z × PW) + JV (5) i = (X−r / 2) / (Z × PW) + IV (6) The mounting position of the CCD camera 11 is In the XYZ coordinate system of the real space, for example, the right CCD camera 1
1b: X = 0.45m, Y = 1.24m, Z = 0.0
m (CCD camera 12b differs only in X, X = 0.20
m), and the left CCD camera 11a sets X = −0.
45m, Y = 1.24m, Z = 0.0m (X = -0.20m for the CCD camera 12a).

FIG. 15 shows a functional configuration of the image processing / inter-vehicle distance control computer 110. The road detector 1 mainly includes a microprocessor 110a.
30, an object recognition unit 140 by the microprocessor 110b, and an inter-vehicle distance control unit 160 by the microprocessor 110c. The processing results of the road detection unit 130 and the object recognition unit 140 The inter-vehicle distance control unit 1 is stored in the three-dimensional object parameter storage unit 150 and is controlled by the microprocessor 110c.
60 and other devices (not shown) for ADA.

Further, the function of the road detector 130 is as follows.
Road shape estimation unit 131, three-dimensional window generation unit 13
2. The function of the object recognition unit 140 is subdivided into a linear element detection unit 133 and a road shape determination unit 134.
41, a three-dimensional window generator 142 and an object contour image extractor 143. The inter-vehicle distance control unit 16
The function of 0 is subdivided into a throttle control unit 161 and a brake control unit 162 for realizing the function of the inter-vehicle distance control unit, and an alarm determination unit 163 for realizing the function of the alarm output unit.

The road detecting section 130 uses the three-dimensional position information based on the distance image stored in the distance image memory 20b to separate and extract only the white line on the actual road, and extracts the built-in road model. The road shape is recognized by modifying / changing the parameters to match the actual road shape.

In an actual image, a preceding vehicle or the like overlaps with a white line on the road. However, in many conventional devices that detect the white line of the road in the image by relying on two-dimensional features, a white line and a three-dimensional image are detected. In many cases, it is difficult to separate an object from the object by two-dimensional characteristics. However, this apparatus can reliably separate the three-dimensional object from the white line by using the three-dimensional position information of the white line. it can. That is, in the three-dimensional space, the white line is on the plane of the road, while a three-dimensional object such as a preceding vehicle is located higher than the road plane. Therefore, the white line and the three-dimensional object are distinguished by the height from the road surface.

Further, a road model is built in the road detecting unit 130. This road model divides the own lane of the road up to the recognition target range into a plurality of sections according to the set distances. The left and right white lines are approximated by a three-dimensional linear expression described later and connected in a polygonal line shape, and the area surrounded by the left and right polygonal lines is determined as the traveling lane of the vehicle. Recognition of a road shape can be said to be a process of deriving parameters of a three-dimensional linear equation.

FIG. 16 shows an example of a road model.
The road up to 84 m ahead is defined as the 0th section R0, the 1st section R1,
It is divided into seven sections of a second section R2,..., And a sixth section R6, and the left curve is approximately expressed. In this road model, 7
By approximating the road in the number of sections, not only straight roads but also curves and S-shaped roads can be expressed with sufficient accuracy.
Since each section is represented by a straight line, calculation processing and handling are easy. Further, as will be described later, each section is represented by a straight line in the horizontal direction and the vertical direction, and can also represent the vertical shape of the road, such as up and down and unevenness of the road.

The value of the distance separating each section of the road model needs to be changed according to the curvature of the curve of the road on which the vehicle runs. On ordinary highways, the radius of the curve is designed to be at least 230 m, so in such a case,
The break distance of each section is 10m, 17m, 25m, 35
Good results are obtained with m, 48 m, 64 m and 84 m.

Next, the function of the road detector 130 will be described in detail. In the road shape estimating unit 131, the previous time (Δts
Based on the recognition result of the road shape (before ec), the movement of the vehicle 1 for Δt seconds is calculated using output signals from the vehicle speed sensor 8 and the steering angle sensor 19, and the movement of the vehicle 1 is viewed from the position of the vehicle 1 after Δt seconds. Estimate the road shape.

That is, the output signal of the vehicle speed sensor 8 is
(M / sec), assuming that the output signal (steering angle) of the steering angle sensor 19 attached to the steering column is η (rad), the advance amount ΔZ (m) and the rotation angle (yaw angle) Δθ of the vehicle 1 for Δt seconds. (Rad) can be generally estimated by the following equation.

ΔZ = V × Δt (7) Δθ = ΔZ × tan (η / rs) × 1 / wb (8) where, rs: the rotation ratio between the steering wheel and the front wheel, wb: the wheelbase of the vehicle. .

Accordingly, the road shape detected in the previous process is moved forward by ΔZ, and the road shape is rotated by Δθ in the direction opposite to the rotation of the vehicle 1, so that the approximate position of the road after Δt seconds is obtained. And the shape can be estimated.

The three-dimensional window generating unit 132 has a rectangular parallelepiped three-dimensional space area as shown in FIG. 17 around one linear element Ld of the left and right polygonal lines representing the estimated road shape RD, that is, a three-dimensional window. WD3A is set, and what the set three-dimensional window WD3A looks like on a two-dimensional image as shown in FIG. 18 is calculated, and the inside of the window outline (shaded portion in FIG. 18)
Is a two-dimensional window WD2A, and only the data in this is a detection target.

To obtain the two-dimensional window WD2A from the three-dimensional window WD3A, the 8
From the coordinates (Xn, Yn, Zn) of the vertices, the coordinates (in, jn) on the image are calculated using the above-described equations (5) and (6), and a polygon that envelopes these points is calculated. I do.

The three-dimensional window WD3A has a length corresponding to the section distance of each section (for example, 10
17m), while the height and width are changed according to the conditions such as the vehicle speed. However, when there is an error in estimating the road shape and a deviation from the actual position of the white line is expected,
Increase the height and width to widen the detection range. However, if the window is too large, curbs and vegetation around the road will also be detected, causing false recognition.
It is important to properly select the size of the window. When traveling on a general highway, the test result showed that the height was 0.1 mm.
It has been found that it is better to change the width in the range of 4 m to 0.8 m and the width of 0.4 to 1.6 m.

As described above, even when the white line of the road and the three-dimensional object overlap on the two-dimensional image, the three-dimensional window is set and only the data near the road surface is extracted, so that the white line can be regarded as the three-dimensional object. Can be detected separately. In addition, there are curbs and vegetation around the road. By setting a three-dimensional window and extracting only data near the position where the white line is presumed to be present, the white line on the road can be used to convert these curbs and vegetation. And can be detected separately. Furthermore, by setting a two-dimensional window, the area to be searched and the number of data can be reduced, and the processing time can be shortened.

The linear element detecting section 133 calculates the X-axis deviation amount X in the X direction and the Y-axis deviation amount ΔY of the three-dimensional position of the subject with respect to the linear element Ld of the road shape estimated previously, and calculates the deviation amount ΔX , ΔY are multiplied to each data, and a linear equation in the horizontal direction (XZ direction) and the vertical direction (YZ) direction is derived by the least square method to obtain parameters.

More specifically, first, the two-dimensional window WD2A
Are sequentially surveyed, and the three-dimensional position (X, Y, Z) of the subject is calculated for the pixels having the distance data using the above-described equations (3) and (4), and the distance Z is calculated. Is in the range of the length of the three-dimensional window WD3A (for example, the first
In the section R1, distance data outside Z = 10 to 17 m) is excluded from detection targets.

That is, the image of the object on the other side or the near side of the three-dimensional window WD3A is
The subject surveyed in the two-dimensional window WD2A is not necessarily included in the three-dimensional window WD3A because the subject is reflected in the D2A. Therefore, the three-dimensional position (X, Y, Z) of the subject of each pixel is calculated, and the three-dimensional window WD3A is calculated.
Is determined.

Subsequently, the three-dimensional position of the subject is compared with the straight-line element Ld of the road shape estimated previously, and the deviation amounts ΔXi, ΔYi in the X and Y directions of the data Di as shown in FIG.
Is calculated, and only data within the range of the width and height of the three-dimensional window WD3A is selected. Then, the weight coefficient of the data Di according to the shift amounts ΔXi and ΔYi in the X and Y directions is determined.

As shown in FIG. 20, the weight coefficient is, for example, a parabola having a center at 1.0 and a periphery at 0.0.
The product of the weight coefficient fx in the X direction and the weight coefficient fy in the Y direction is
The weight coefficient of the data Di is used. Further, the range in the X direction and the Y direction in which the weight coefficient is 0.0 or more is the same as the width and height of the three-dimensional window WD3A, or
Make them larger.

After multiplying each data Di by the weighting coefficient, the following equations (9) and (10) are obtained using the least squares method.
The horizontal and vertical linear equations shown in the equations are derived, and parameters a, b, c, and d are obtained.
d is a candidate.

Horizontal direction: X = a × Z + b (9) Vertical direction: Y = c × Z + d (10) At the same time, the weight coefficient is set to a set value (for example, 0.05 to 0.1).
The number of data and the range of the distance Z over which the data is distributed are examined. If the number of data is equal to or smaller than a set value (for example, about 10), or the range of the distance Z is three-dimensional window WD3A. (For example, Z = 10 m to 17 m in the first section R 1, length 7 m) or less, it is determined that an accurate candidate for the linear element Ld has not been obtained. The rejected straight line formula is rejected and there is no candidate.

The above processing is sequentially performed from the left and right and the near side to the far side section, and candidates for all the linear elements Ld constituting the road model are obtained. In this case, if the width of the three-dimensional window is set too large, a curb or a plant around the road may hang over the edge of the three-dimensional window. By reducing the weight of the periphery of the three-dimensional window by multiplying it, even if curbs or vegetation are applied, these effects can be reduced, and the linear equation of the white line can be derived stably. is there.

The road shape determination unit 134 determines the validity of each of the left and right straight line element Ld candidates from the horizontal and vertical parallelism for each section. As a result of the determination, if both are adopted as candidates for a new linear element Ld, if both are adopted as candidates for a new linear element Ld, and if it is determined that the candidate for one of the left and right linear elements Ld is not accurate, Perform substitution and completion. Then, the obtained parameters of each linear element Ld are output to the road / solid object parameter storage unit 150.

Specifically, first, a parameter aL of the equation (9) (hereinafter, L representing the left side and R representing the right side are added to each parameter) for the left side linear element Ld, and a right side linear element Ld From the difference between Ld and the parameter aR in the equation (9), the parallelism in the horizontal direction is checked. If the parallelism is equal to or larger than a set value (for example, about 5 °), it is determined that the right or left linear element Ld is incorrect judge. Similarly, the degree of parallelism in the vertical direction is checked from the difference between the parameters cR and cL, and if it is equal to or greater than a set value (for example, about 1 °), it is determined that any of the linear elements is incorrect.

As a result of this determination, if the parallelism in both the horizontal direction and the vertical direction satisfies the conditions, both are adopted as new linear elements.
If it is determined that d is incorrect, each of the left and right linear elements Ld
Is compared with the position of the road shape estimated previously, and the one with the smaller amount of deviation is adopted as a new linear element Ld, and the other is rejected to be no candidate.

Then, if either of the left and right straight line elements Ld is determined to be no candidate by the determination of the parallelism, or if the white line on the road is a broken line or hidden behind obstacles, data is insufficient. And either straight line element Ld
Is determined that there is no candidate, the linear element Ld on the detected side is moved in parallel by the width of the lane and substituted. Further, when both the left and right straight line elements Ld have no candidate, the straight line element Ld of the previously estimated road shape is substituted. As a result, even if partial linear element detection failure or erroneous detection occurs, a stable road shape can be obtained as a whole.

FIG. 21 is an explanatory diagram schematically showing the road shape detected by the road detecting section 130, in which linear elements are detected along left and right white lines. A portion that is hidden by a vehicle ahead and cannot be seen is satisfactorily estimated by complementing as described above. The horizontal line between the left and right linear elements is
This is the boundary of each section.

Next, the object detection unit 141, the three-dimensional window generation unit 142 in the object recognition unit 140, and
Each function of the object contour image extraction unit 143 will be described in detail.

In the object detection section 141, the distance images from the image processor 20 are arranged at predetermined intervals (for example,
(8 to 20 pixel intervals), and for each region, only data of a three-dimensional object that may be an obstacle to traveling is selected and its detection distance is calculated.

FIG. 22 is an explanatory diagram in which a grid-like area is set on a bright and dark image obtained by capturing a scene in front of the vehicle 1, and the distance image in FIG. 12 is actually divided in this way. In this embodiment, the area is divided into 33 small areas at intervals of 12 pixels. That is, a plurality of objects can be detected simultaneously by dividing an image into a large number of regions and searching for objects.

The subject in each area is determined from the coordinates (i, j) on the image and the distance data Z as described in (3) and (4) above.
The three-dimensional position (X, Y, Z) of the real space is calculated using the equation, and the height Yr of the road surface at the distance Z is calculated using the equation (10) of the road shape detected earlier. Is calculated.
The height H of the subject from the road surface can be calculated by the following equation (11).

H = Y−Yr (11) A subject having a height H of about 0.1 m or less is a white line, a dirt, a shadow, or the like on a road, and is not considered to be an obstacle to traveling. The data of this subject is rejected. In addition, subjects above the height of the vehicle 1 are also discarded because they are considered to be pedestrian bridges and signs, and only data of three-dimensional objects that become obstacles on the road are selected. Thus, even if an object overlaps a road or the like on a two-dimensional image, data can be distinguished based on the height from the road surface, and only the object can be detected.

Next, with respect to the data of the three-dimensional object extracted in this manner, the number of data included in the section of the preset distance Z is counted, and a histogram having the distance Z as a horizontal axis is created. FIG. 23 is a histogram with the preceding vehicle 500 as the detection object.

The length and the number of sections of the distance Z to be set need to be determined in consideration of the detection limit and accuracy of the distance Z, the shape of the object to be detected, and the like. In this case, the section length should be about 1.5 m 10 m ahead and about 15 m 100 m ahead.

In the above-mentioned histogram, since the distance data in the input distance image includes a value which is erroneously detected, some data appears at a position where no object actually exists. However, if there is an object of a certain size, the frequency at that position shows a large value, while if there is no object, the frequency generated only by incorrect distance data has a small value.

Therefore, if there is a section where the frequency of the created histogram is equal to or greater than a predetermined judgment value and has a maximum value, it is determined that an object exists in that section, and if the maximum value of the frequency is equal to or less than the judgment value, By judging that the object does not exist, the object can be detected while minimizing the influence of the noise even when the image data includes some noise.

When it is determined that an object exists, the average value of the distance Z between the detected section and the data of the three-dimensional object included in the preceding and succeeding sections is calculated, and this value is calculated as the distance to the object. Is considered.

After such a process of detecting the distance to the object has been performed for all the regions, the detection distance of the object in each region is checked. If the difference in the detection distance to the object in the adjacent region is equal to or smaller than the set value, the distance is the same. Are regarded as separate objects, while if the set value is exceeded, they are regarded as separate objects.

More specifically, first, the area AR1 at the left end is examined, and if an object is detected, it is detected as an object S1,
Let the distance be Z1. Next, the area AR2 on the right side is examined, and if no object is detected, the object S1 exists inside and near the area AR1, the distance is determined to be Z1, the object is detected, and the detection distance is determined. Is Z2, the distance Z1
And the difference between Z2.

If the difference between the distances Z1 and Z2 is equal to or larger than the set value, it is determined that the object detected in the area AR2 is different from the previously detected object S1.
And then check the area on the right.

On the other hand, if the difference between the distances Z1 and Z2 is equal to or smaller than the set value, the object detected in the area AR2 is determined to be the previously detected object S1, and the distance is the average of Z1 and Z2. Then, the area on the right side is sequentially examined, and if it is determined that the object S1 is continuously present, the distance and the existing area are updated.

Conventionally, it has been difficult to extract only the data of an object when a distant background is present around the object on a two-dimensional image. By performing data from the left end area AR1 to the right end area AR33 and distinguishing data according to the distance value, a plurality of objects, their distances, and existence areas can be detected separately from the background. Even in the case where a plurality of objects are photographed overlapping each other, the objects can be distinguished and detected depending on the difference in the distance between the objects.

The set value is about 4 m to 6 m when detecting an automobile, and 1 m to 6 m when detecting a pedestrian.
It has been experimentally obtained that the distance should be about 2 m.

FIG. 24 shows the existence area of the object detected by the above processing by a frame line. In this example, three objects are detected. In addition, the numerical value on the lower side of the figure is the detection distance of each object.

In the three-dimensional window generating section 142, each object detected by the object detecting section 141 is detected in a three-dimensional space as shown in FIG.
Cuboidal three-dimensional space region containing 500, ie, 3
Set a three-dimensional window WD3B, calculate how the three-dimensional window WD3B looks on a two-dimensional image, detect the data inside the two-dimensional window WD2B inside the window outline set to target.

The three-dimensional window WD3B for detecting the object
Is a range extended by one region to the left and right from the region where the object exists. This is because, if only a part of the left and right edges of an object is over a certain area, that object does not have a large value on the histogram and another object may be detected. In consideration of the above, the range of the window is expanded.

The length of the three-dimensional window WD3B in the distance Z direction is a range obtained by adding the section length of the histogram at the detection distance of the object before and after the detection distance. The lower end of the three-dimensional window WD3B is a position obtained by adding about 0.1 m to the height of the road surface, and the upper end is the upper end of each area divided for object detection.

The three-dimensional window WD3B for object detection
The processing for obtaining the two-dimensional window WD2B for object detection from the three-dimensional window generation unit 1 of the road detection unit 130 is first performed.
32.

FIG. 26 shows an example in which a two-dimensional window WD2B is set for one of the three detected objects shown in FIG.

The object contour image extracting section 143 performs a process of sequentially surveying each data in the two-dimensional window WD2B, selecting only data included in the three-dimensional window WD3B, and extracting a contour image of the detected object. Then, the position of the detected object, such as the position, speed, and acceleration, of the positional relationship with the own vehicle is detected, the preceding vehicle with respect to the own vehicle 1 is specified, and the inter-vehicle distance and the relative speed are calculated.

That is, first, each data in the two-dimensional window WD2B is surveyed sequentially for each object, and the three-dimensional position (X) of the pixel having the distance data is calculated by using the above-mentioned equations (3) and (4). , Y, Z), only data whose distance and height values are within the range of the three-dimensional window WD3B are extracted, and the others are rejected.

FIG. 27 shows the data extracted in this manner projected onto a two-dimensional image and displayed. Furthermore, by connecting the outlines of these data with line segments, FIG.
The contour image of the object as shown in FIG. 8 is obtained. The coordinates (i, j) of the left and right ends and the upper end of this contour image on the image are detected, and subsequently, using the detection distance Z of the object and the equations (3) and (4), the three-dimensional space is obtained. When the positions of the left and right ends and the upper end of the object are calculated, the lateral width of the object is obtained from the positions of the left and right ends, and the height of the object is obtained from the upper end position. In FIG. 28,
It can be determined that the object is 1.7 m in width and 1.3 m in height.

The center position (X, Z) of the left and right ends of the object
Is calculated, and from the time change of the distance Z, the own vehicle 1
The relative velocity in the front-back direction of the object viewed from is calculated, and
The relative speed in the left-right direction is calculated from the temporal change in the position X in the left-right direction. Further, when the relative speed of the object is added to the traveling speed of the vehicle input from the vehicle speed sensor 8, the traveling speed of the object with respect to the road surface is calculated, and the acceleration of each object is calculated from the time change of the traveling speed.

Subsequently, the position of each detected object is compared with the position of the previously detected lane of the road, and whether the object is on the own lane, on the left or right lane, or outside the road. Investigate and classify each. For example,
If multiple vehicles are traveling ahead and the road is curved, the position of each object is compared along the path, and the object located closest in the own lane is determined to be the preceding vehicle. , And the distance to the object is the inter-vehicle distance.

The parameters such as the position, shape, speed, and acceleration of each object obtained as described above, and the inter-vehicle distance to the preceding vehicle specified from these data are set on the road / road.
When stored in the three-dimensional object parameter storage unit 150, these data are read into the inter-vehicle distance control unit 160, and inter-vehicle distance control is performed.

The inter-vehicle distance control section 160 mutually executes the control processing of the throttle actuator 3 by the throttle control section 161 and the control processing of the parking brake actuator 6 by the brake control section 162 to determine the inter-vehicle distance with the preceding vehicle. At the same time, the alarm judging section 163 performs a process of predicting the possibility of abnormal approach to the preceding vehicle in parallel with these processes. If there is a possibility of abnormal approach, an alarm is issued by the display 9. Emit. Hereinafter, these processes will be described.

First, in the throttle control section 161,
The traveling speed Ve of the own vehicle 1 is input from the vehicle speed sensor 8 and the traveling speed VQ of the preceding vehicle is calculated from the relative speed Vr with respect to the preceding vehicle according to the following equation (12). Is obtained, for example, by the following equation (13).

VQ = Ve + Vr (12) Ds = DsQ−Ve ² /(2.0×Ae)+VQ ² /(2.0×AQ)+Dm (13) Here, the first expression of the expression (13) The term DsQ is a target inter-vehicle distance when the own vehicle and the preceding vehicle are stopped (for example, a value of about 4 m).
The second term (Ve ² /2.0×Ae) is the braking distance when the vehicle 1 brakes at the deceleration Ae from the speed Ve.
The deceleration Ae is set in consideration of the braking capacity of the parking brake 5, the ride comfort of the driver, and the like.
The value is about 0 m / s ² . Incidentally, the parking brake actuator 6 is provided with a deceleration A generated when the brake is operated.
In order for e to be such a value, wire cable 6
Adjust the length of a and the like.

The third term (Ve ² /2.0) in the equation (13)
× AQ) is an estimated braking distance when it is assumed that the preceding vehicle brakes at the deceleration AQ. Here, the value of AQ is, for example, assuming a state where the preceding vehicle has suddenly braked,
It is set to a value of about 6.0 m / s ² (constant value). Further, Dm in the fourth term is a margin of the inter-vehicle distance, and is set to, for example, about 2 m to 5 m.

Next, from the difference between the target inter-vehicle distance Ds set as described above and the current inter-vehicle distance Dr and the relative speed Vr, the state of the preceding vehicle corresponds to any of the speed control modes for controlling the speed of the own vehicle. Is determined, and the opening degree Ts of the throttle valve 2 is determined according to the corresponding speed control mode. The concept of speed control mode determination will be described with reference to FIG. 29 where the distance between vehicles is the vertical axis and the relative speed is the horizontal axis.

In FIG. 29, a boundary line S1 having both ends of the point where the relative speed Vr is positive and the inter-vehicle distance is 0 and the target inter-vehicle distance Ds is set by the following equation (14).
A boundary line S2 having both ends of the point where r is negative and located at the detection limit distance of the preceding vehicle and the target inter-vehicle distance Ds is as follows (15).
Set by expression.

Dr = Ds−Vr ² /(2.0×Aa) (14) Dr = Ds−Vr ² /(2.0×Ac) (15) Here, Aa in the equation (14) is This is an estimated value of acceleration generated when the vehicle 1 accelerates by opening the throttle valve 2, and is, for example, a value of about 0.2 m / s ² . Ac in the equation (15) is a deceleration that occurs when the vehicle 1 decelerates by the engine brake by fully closing the throttle valve 2 and, for example, −0.2.
The value is about m / s ² .

The lower left side of each of the boundary lines S1 and S2 is a region R3, the upper side of the boundary line S2 is a region R2, the upper side of the boundary line S1 is a region R1, and the detection limit distance which is determined to be no preceding vehicle is longer than the detection limit distance. The opening degree of the throttle valve 2 is determined in accordance with the region R4 and the region where the detected inter-vehicle distance Dr and the relative speed Vr to the preceding vehicle are located.

That is, when the preceding vehicle exists in the region R3, the throttle valve 2 is in the speed control mode in which the throttle valve 2 is fully closed to decelerate. When the preceding vehicle exists in the region R2, the throttle is opened. The degree Ts is a speed control mode that is proportional to the difference between the inter-vehicle distance Dr and the target value Ds, for example, as in the following equation (16).

Ts = K2 × (Dr−Ds) + Tv (16) Here, Tv in the equation (16) is a throttle opening required to maintain the current speed Ve, and depends on each vehicle characteristic. It is a determined value. Therefore, characteristics are measured in advance for each vehicle, and the relationship between the speed Ve and the throttle opening Tv is determined. K2 is a proportional constant, and an appropriate value is determined for each vehicle.

When the preceding vehicle exists in the region R1, the throttle opening Ts is in a speed control mode determined by the following equations (17) and (18), for example.

Ts = K2 × (Dr′−Ds) + Tv (17) Dr ′ = Dr + Vr ² /(2.0×Aa) (18) Dr ′ in the equation (18) is the acceleration of the vehicle 1. This is an estimated value of the inter-vehicle distance when the relative speed Vr with respect to the preceding vehicle decreases when the vehicle accelerates at Aa and finally becomes zero.
Is replaced with Dr 'in the above equation (15) to obtain equation (17).

Further, in a region R4 where the preceding vehicle is longer than the detection limit distance, the own vehicle 1 moves at a predetermined speed (for example, 10 km).
/ H) is a speed control mode for controlling the throttle opening Ts so as to be constant at / h). In the case where the throttle opening Ts is controlled in the regions R1 and R2, a limit value (for example, 10 km / h) is provided for the speed so that the speed is not exceeded.

As described above, the throttle opening Ts is determined, and a signal is sent to the throttle actuator 3 which is operated by a servomotor or air pressure to control the opening of the throttle valve 2.

On the other hand, the brake control unit 162 determines the speed control mode for operating the parking brake 5 from measured values such as the following distance Dr, the speed VQ of the preceding vehicle, and the speed Ve of the own vehicle.

First, an inter-vehicle distance Dn required for controlling the parking brake 5 is calculated by the following equation (19). This equation (19) is obtained by removing the allowance Dm (fourth term) of the following distance from the above-mentioned equation (13).

Dn = DsQ−Ve ² /(2.0×Ae)+VQ ² /(2.0×AQ) (19) Next, it is determined whether or not the current inter-vehicle distance Dr is smaller than the required inter-vehicle distance Dn. If Dr <Dn, the parking brake actuator 6 is operated to decelerate or stop,
On the other hand, if Dr ≧ Dn, the parking brake actuator 6 is released.

In the throttle control in the throttle control section 161 and the brake control in the brake control section 162, the formula (13) for calculating the target inter-vehicle distance Ds for controlling the throttle and the necessity for controlling the brake are provided. As can be seen by comparing equation (19) for calculating the inter-vehicle distance Dn, the target inter-vehicle distance Ds is equal to the required inter-vehicle distance Dn.
It becomes a value larger by the margin Dm than that.

Therefore, when the inter-vehicle distance Dr with the preceding vehicle decreases to reach the required inter-vehicle distance Dn and the parking brake actuator 6 is actuated, the inter-vehicle distance Dr with the preceding vehicle is already smaller than the target inter-vehicle distance Ds. Has become.
At this time, the throttle valve 2 is controlled to be fully closed, and the throttle actuator 3 and the parking brake actuator 6 do not operate simultaneously.

However, from the viewpoint of fail-safe, the parking brake actuator operation signal from the brake control unit 162 is also input to the throttle control unit 161, and the throttle control unit 161 receives the parking brake actuator operation signal. , So that the throttle valve 2 is fully closed.

Further, the warning judging section 163 sets the estimated inter-vehicle distance after a lapse of a predetermined time when the own vehicle 1 is decelerated at the deceleration Ae as an alarm inter-vehicle distance Dw at which an alarm is issued by the following equation (20). After the calculation, if the current inter-vehicle distance Dr is smaller than the warning inter-vehicle distance Dw, a warning is issued to the driver.

Dw = Dsw−Ve ² /(2.0×Ae)+VQ ² /(2.0×AQ) (20) The first term Dsw in equation (20) is the first term Dsw in equation (19). This is a replacement of the first term DsQ, and is an inter-vehicle distance when the host vehicle and the preceding vehicle are stopped. For example, the first of equation (19)
While the term DsQ is set to about 4 m, the first term Dsw of the equation (20) is smaller than the first term DsQ of the equation (19), and 1
m.

That is, by estimating in advance the possibility of an abnormal approach to the preceding vehicle and issuing an alarm, a sufficient time margin can be given to the driver's brake operation, and safety can be further improved. You can.

Next, the operation of this embodiment will be described.

FIG. 30 is a flowchart showing the flow of the operation of the image processor 20. First, at step S1
When images captured by the left and right CCD cameras 11a and 11b are input in 01, in step S102, the input analog images are A / D converted into digital images having predetermined luminance gradations by the A / D converters 31a and 31b. , LUT
At 32a and 32b, the contrast of the low luminance portion is enhanced, the characteristics of the left and right CCD cameras 11a and 11b are compensated, and the like are stored in the image memories 33a and 33b.

The images stored in the image memories 33a and 33b are only the lines necessary for the subsequent processing among all the lines of the CCD elements of the CCD cameras 11a and 11b, for example, once every 0.1 second. Percentage (3 in TV image)
(One per sheet).

Next, when the flow advances to step S103, the input buffer memory 4 is transferred from the image memories 33a and 33b for the left and right images.
Left and right image data are read into, for example, four lines at 1a, 41b, 42a, and 42b via the common bus 80,
Matching of the read left and right images, that is, evaluation of the degree of coincidence is performed.

At this time, for each of the left and right images, the input buffer memories 41a, 41b are read from the image memories 33a, 33b.
1b, 42a, 42b, and write operations to the shift registers 43a, 43b, 44a, 44b are performed alternately. For example, in the case of the left image, while the image data is being read from the image memory 33a to one input buffer memory 41a, the image data read from the other input buffer memory 41b to the shift register 43b is written out, and the right image is read. In the process, while the image data is being read from the image memory 33b to the one input buffer memory 42a, the image data read from the other input buffer memory 42b to the shift register 44b is written.

As shown in FIG. 31, the shift registers 43a, 43b, 44a and 44b store image data (1, 1)... (4, 4) of a small area of right and left 4 × 4 pixels. One shift register 43a (44a) has 1,
Two lines of data are stored in the other shift register 43b.
In (44b), data of lines 3 and 4 are entered in order of odd lines and even lines for each pixel. Each of the shift registers 43a, 43b, 44a, and 44b has an independent transfer line, and data of 4 × 4 pixels is transferred at, for example, eight clocks.

The shift registers 43a, 43a
43b, 44a, and 44b simultaneously output the contents of the even-numbered stages among the eight stages to the city block distance calculation circuit 45,
When the calculation of the city block distance H starts, the data of the right image is held in the shift registers 44a and 44b, and the data of the odd lines and the even lines are output alternately every clock, while the data of the left image is shifted. Register 43
a, 43b, while the data of the odd-numbered lines and the even-numbered lines are alternately output, and are replaced by data shifted to the right by one pixel every two clocks. This operation is performed until, for example, 100 pixels are shifted (200 clocks).
repeat.

Thereafter, when the transfer to one small area is completed, the contents of the right image address counter (the head address of the next 4 × 4 pixel small area) are stored in the left image address counter in the # 2 address controller 87. Set,
Processing of the next small area starts.

In the city block distance calculation circuit 45, as shown in the timing chart of FIG. 32, first, data of 8 pixels is input to the absolute value calculator of the first stage of the pyramid structure, and the absolute value of the luminance difference between the left and right images is obtained. Is calculated. In other words, the luminance of the corresponding left pixel is subtracted from the luminance of the right pixel, and if the result is negative, the arithmetic instruction is changed so that the subtraction and the subtraction are performed in reverse, and the subtraction is performed again. Calculate the value. Therefore, the subtraction may be performed twice in the first stage.

Next, after passing through the first stage, 4
The first to third adders up to the second stage add and output two simultaneous input data. Then, the total sum adder at the final stage adds two consecutive data to calculate the sum, and outputs the required city block distance H for 16 pixels to the minimum / maximum value detection unit 50 every two clocks.

Next, the process proceeds to step S104, wherein
The maximum value HMAX of the city block distance H calculated in S103,
The minimum value HMIN is detected. As described above, the detection of the maximum value HMAX and the detection of the minimum value HMIN are exactly the same except that the logic is reversed and the deviation amount is not preserved. The detection of the value HMIN will be described.

First, the city block distance H (shift amount x = 0) output first is input to the B register 46b of the arithmetic unit 46 via the C latch 53 of the minimum value detection circuit 51 shown in FIG. Is done. The city block distance H (displacement amount δ = 1) output at the next clock is input to the C latch 53 and the A register 46a of the arithmetic unit 46, and the arithmetic unit 46 simultaneously compares it with the B register 46b. The operation starts.

As a result of the comparison operation by the arithmetic unit 46, if the content of the A register 46a is smaller than the content of the B register 46b, the content of the C latch 53 (ie, the content of the A register 46a) is obtained at the next clock. Is transferred to the B register 46b, and the shift amount δ at this time is stored in the D latch 55. Simultaneously with this clock, the next city block distance H (shift amount δ = 2) is input to the A register 46a and the C latch 53, and the comparison operation starts again.

In this way, the calculation is continued until the shift amount δ reaches 100 while the minimum value during the calculation is always stored in the B register 46b and the shift amount δ at that time is stored in the D latch 55. When the calculation is completed (one clock after the last city block distance H is output), the contents of the B register 46b and the D latch 55 are read into the shift amount determining unit 60.

In the meantime, the above-mentioned city block distance calculation circuit 45 reads the initial value of the next small area so that time is not wasted. To calculate one city block distance H, For example, although it takes four clocks, a new calculation result is obtained every two clocks because of the pipeline structure.

When the minimum value HMIN and the maximum value HMAX of the city block distance H are determined in step 104, in step S105, the above-described three conditions are checked by the shift amount determining unit 60, and the shift amount x is determined. It is determined.

That is, as shown in the timing chart of FIG. 33, the minimum value HMIN is latched by the B register 72 of the arithmetic unit 61 via the B bus 62b and is compared with the value of the B register 72. The value HA is latched in the A register 71 via the A bus 62a. The two are compared by the ALU 70, and if the minimum value HMIN is larger than the threshold value HA, the switch circuit 65 is reset, and 0 is always output regardless of the subsequent check.

Next, the maximum value HMAX is latched in the A register 71, and the maximum value H
The difference between MAX and the minimum value HMIN stored in the B register 72 is calculated, and the result is output to the F register 73. At the next clock, the threshold value HB is latched in the A register 71 and compared with the value of the F register 73. F register 7 is higher than threshold value HB latched in A register 71.
If the content of 3 is smaller, the switch circuit 65 is similarly reset.

The calculation of the luminance difference between adjacent pixels starts from the next clock. The two sets of shift registers 64a and 64b in which the luminance data are stored have a ten-stage configuration. The shift registers 44a for the first and second lines of the city block distance calculator 40 and the shift registers for the third and fourth lines are respectively provided. It is connected to the subsequent stage of 44b. The outputs of the shift registers 64a and 64b are taken from the last stage and the stage immediately before the last stage, and output to the A bus 62a and the B bus 62b, respectively.

When the calculation of the luminance difference starts, the luminance data of each location in the small area is held in each stage of the shift registers 64a and 64b.
The luminance data of the first row and the first column and the luminance data of the first row and the first column of the current small area are latched by the A register 71 and the B register 72 of the arithmetic unit 61.

Then, the absolute value of the difference between the contents of the A register 71 and the contents of the B register 72 is calculated, and the result is stored in the F register 73. At the next clock, the threshold value HC is latched in the A register 71 and is compared with the value of the F register 73.

As a result of the comparison in the arithmetic unit 61, if the content (absolute value of the luminance difference) of the F register 73 is larger than the content (threshold value HC) of the A register, the shift amount x or "0" is output and A
If the content of the F register 73 is smaller than the content of the register, "0" is output and the output buffer memory 66
a, 66b are written at the positions corresponding to the first row and first column of the corresponding small area.

While the arithmetic unit 61 compares the luminance difference between adjacent pixels with the threshold value HC, the shift registers 64a and 64b shift one stage. And this time,
The calculation is started for the fourth row and second column of the previous small area and the luminance data of the first row and second column of the current small area. After the calculation is alternately performed on the first and second columns of the small area in this manner, the calculation is similarly performed on the third and fourth columns.

During the calculation, the shift registers 64a, 64b
And the first stage are connected to form a ring register. After calculating the entire small area, the shift clock becomes 2
When the register is added twice, the contents of the register return to the state before calculation,
When the transfer of the luminance data of the next small area is completed, the data of the fourth row of the current small area is retained in the last stage and the previous stage.

As described above, during the calculation for determining the shift amount, the next data is prepared on the A bus 62a and the B bus 62b and the result is written. Is processed. As a result, even if the minimum value HMIN and the maximum value HMAX are checked first, all calculations are completed at, for example, 43 clocks, and the minimum value HMI of the city block distance H is calculated for one small area.
N, the time required to find the maximum value HMAX has ample room, and it is possible to add more functions.

When the shift amount x is determined, the shift amount x is output as distance distribution information from the output buffer memories 66a and 66b to the dual port memory 90 in step S106, and the processing in the image processor 20 ends. .

The output buffer memories 66a and 66b
Are the input buffer memories 41a, 41b, 42 described above.
a, 42b, for example, has a capacity for four lines,
While writing to one of the sets, distance distribution information is sent from the other to the dual port memory 90.

From the distance distribution information written in the dual port memory 90, the three-dimensional position of the object corresponding to each pixel in the XYZ space can be determined from the mounting positions of the CCD cameras 11 and 12 and lens parameters such as the focal length. The distance to the object outside the vehicle can be accurately detected without a decrease in the amount of information.

Here, the overall timing of the image processor 20 will be described with reference to the timing chart shown in FIG.

First, the left and right CCs that are synchronized
The field signals from the D cameras 11a and 11b are
Every second (the ratio of one screen to three screens), the image memory 33a,
Write to 33b.

Next, upon receiving the capture end signal, block transfer for every four lines starts. In this transfer, three blocks are transferred in the order of the right image, the left image, and the resulting distance distribution image.

In the meantime, the deviation amount δ is calculated for one input / output buffer memory. Then, in consideration of the calculation time of the deviation amount δ, the transfer to the other input / output buffer memory is started after waiting for a predetermined time.

The calculation of the city block distance H for a small area of 4 × 4 pixels of one right image is performed by 10
It is performed 100 times to calculate while shifting by 0 pixel.
While the city block distance H of one area is being calculated, the shift amount δ of the previous area is output as a distance distribution through each check.

Assuming that the number of lines to be processed is 200, the processing for four lines is repeated 50 times, the processing time for four lines for transferring the first data at the start of the calculation, and the final result after the calculation is completed. , And a processing time for a total of eight lines is required.

The time from the start of the transfer of the first input image line to the end of the transfer of the last distance distribution is 0.076 seconds as a result of the actual circuit operation.

On the other hand, the flowcharts of FIGS. 35 and 36 show the road detection processing executed by the microprocessor 110a. First, in step S201, the previous (Δtsec
After reading the road shape parameter of the previous), the process proceeds to step S202, and the output signal V of the vehicle speed sensor 8 and the output signal η of the steering angle sensor 19 are read.

Next, in step S203, the position of the vehicle 1 for Δt seconds is calculated using the output signal of the vehicle speed sensor 8 and the output signal η of the steering angle sensor 19 read in step S202. , The road shape viewed from the position of the vehicle 1 after Δt seconds is estimated, and the road shape parameters are corrected.

When the above road shape estimation processing is completed, the processing shifts to a three-dimensional window generation processing. In step S205, the parameters (a, b, c, d) of the straight line element Ld on the left side of the first section R1 of the road model. Is read, in step S206,
Three-dimensional window WD3A centered on this linear element Ld
Set.

Thereafter, the flow advances to step S207 to set a two-dimensional window WD2A on a two-dimensional image from the three-dimensional window WD3A set in step S206, and then to the next step S208 and subsequent steps.

Steps S208 to S217 are linear element detection processing. In step S208, the two-dimensional window W
When the data in D2A is read, the three-dimensional position of each data is calculated in step S209, and in step S210, data whose distance Z is within the length of the three-dimensional window WD3A is selected.

Then, the flow advances to step S211 to compare the straight line element Ld of the road shape estimated previously with the three-dimensional position of the subject to calculate the displacement amounts ΔX and ΔY in the X and Y directions, and in step S212. , These deviation amounts ΔX, ΔY are 3
Only data within the range of the width and height of the dimension window WD3A are selected, and others are excluded.

Thereafter, the process proceeds to step S213, where the weighting factors of the data are determined in accordance with the deviation amounts ΔX and ΔY in the X and Y directions calculated in step S212, and
Weighting factors corresponding to the deviation amounts ΔX and ΔY are added.

Next, in step S214, the linear equations in the horizontal direction (XZ plane) and the vertical direction (YZ plane) are derived using the least squares method, and the parameters (a, b, c, d) are obtained.
Is obtained, and this is set as a candidate for a new linear element Ld.

At step S215, it is checked whether or not a candidate for the straight line element Ld of the right line of the road model has been obtained. If the result is NO, at step S216, the parameter of the right straight line element Ld is determined. And returns to step S206 described above. If the result is YES, step S2
Proceed to 17.

In step S217, it is checked whether or not the obtained candidate for the linear element Ld is on the right side of the last section. If not, in step S218, the linear element Ld on the left side of the next section is determined. After reading the parameters, the process returns to step S206, and the same process is repeated.

On the other hand, if it is determined in step S217 that the candidate for the linear element Ld obtained is the one on the right side of the final section, and all candidates for the linear element Ld constituting the road model have been obtained, the processing proceeds to step S217. Then, the process proceeds from step S219 to execute the road shape determination processing.

That is, in step S219, the first section R1
When the parameters of the linear element Ld are read, step S2
In step 20, the horizontal parallelism of the left and right linear elements Ld is checked to determine their validity. In step S221, the vertical parallelism of the left and right linear elements Ld is checked to determine their validity.

Thereafter, the process proceeds to step S222, and as a result of the determination in steps S220 and S221, when it is determined that either the right or left straight line element is not valid, or the white line on the road is a broken line or an obstacle. In the case where there is no data because there is no candidate for the right or left linear element because it is hidden behind and cannot be seen, the linear element on the detected side is lost by moving in parallel by the width of the lane and substituted. The linear element is complemented, and the process proceeds to step S223.

When there are no left and right straight line elements, the straight line elements of the road shape estimated earlier are substituted.

At step S223, it is checked whether or not it is the last section. If not, at step S224, the parameters of the left and right straight line elements Ld of the next section are read, and the process returns to step S220. If so, step
Proceeding from S223 to step S225, the parameters of each linear element Ld are written into the output memory 115, and the process ends.

Next, the object recognition processing by the microprocessor 110b will be described with reference to the flowcharts of FIGS. In this object recognition process, step
When the road shape parameters are read in S301, step S302
Then, the distance image from the image processor 20 is divided into grid-like areas, and in step S303, the data of the first area is read.

Next, the process proceeds to step S304, where the first data in the area is set. In step S305, the three-dimensional position (X, Y, Z) of the subject, that is, the distance and height are calculated. Then, the height of the road surface at the distance Z is calculated, and in step S307, data located above the road surface is selected.

The flow advances to step S308 to check whether or not the data is the last data. If the data is not the last data, the next data in the area is set in step S309.
Returning to step 05, the process is repeated, and in the case of the last data, the process proceeds from step S308 to step S310.

Steps S310 to S315 are object detection processing. When a histogram is created in step S310, in step S311, a section where the frequency of the histogram is equal to or greater than the determination value and has the maximum value is detected, and the histogram is determined. If a section in which the frequency is equal to or more than the determination value and has the maximum value is detected, in step S312, it is determined that an object exists in the section, and the distance to the object is detected.

Then, in step S313, it is checked whether or not it is the last area. If it is not the last area, the data of the next area is read in step S314, and the flow returns to step S304 to continue the same processing. If it is the last area, the process proceeds to step S315, where the detection of the distance and the existence area of each object ends, and the process proceeds to the three-dimensional window generation processing of steps S316 to S318.

In step S316, the parameters of the first object are set. Next, in step S317, the height and the distance range of the lower end of the three-dimensional window WD3B are set. In step S318, the three-dimensional window WD3B is used. The shape of the two-dimensional window WD2B is calculated, and the process proceeds to step S319.

The steps following step S319 are the object contour extraction processing. First, at step S319, the two-dimensional window WD2B
When the data in is read out, in step S320, the 3
The dimension position is calculated, and in step S321, data included in the three-dimensional window WD3B is selected and extracted.

Thereafter, the process proceeds to step S322, where the data extracted in step S321 is projected onto a two-dimensional image. In step S323, each data is connected by a line segment to create a contour image. Subsequently, in step S324, the shape, size, position, and speed of the object are calculated, and in step S325, the positional relationship between the lane of the road and the object is calculated.

At step S326, it is checked whether or not the object is the final object. If the object is not the final object, the parameters of the next object are set at step S327, and the process returns to step S317. Proceed to step S328,
The position, shape, speed, acceleration of each object including the preceding vehicle, parameters such as the inter-vehicle distance to the preceding vehicle and the relative speed specified from these data are written in the output memory 115,
The process ends.

By the above processing, the preceding vehicle existing ahead is detected, and the distance between the vehicle and the vehicle 1 and the relative speed with respect to the own vehicle 1 are calculated.
At 0, the program of the throttle control process of FIG. 39 and the program of the parking brake control process of FIG. 40 are executed in parallel at predetermined time intervals.

First, in the throttle control processing, step
In S401, the parking brake actuator 6 is turned off
It is checked whether or not the parking brake actuator 6 is ON and the parking brake is in the operating state.
Branches to 02 and fully closes the throttle opening Ts (Ts = 0.0)
To step S416.

On the other hand, in step S401, if the parking brake actuator 6 is OFF and the parking brake is released, the process proceeds from step S401 to step S403, where the state of the own vehicle 1 and the preceding vehicle, that is,
The detected values of the inter-vehicle distance Dr and the relative speed Vr from the preceding vehicle stored in the output memory 115, the detected value of the speed Ve of the vehicle 1 from the vehicle speed sensor 8, and the like are input.

Next, the process proceeds to step S404, where it is determined whether or not the preceding vehicle is not detected from the input data or if the speed Ve of the own vehicle 1 is higher than a limit value (for example, 10 km / h). If so, in step S405, the throttle opening Ts at which the speed Ve of the vehicle 1 becomes constant at the limit value (for example, 10 km / h) is calculated, and the process proceeds to step S416.
When the preceding vehicle is detected, in step S406, the traveling speed VQ of the preceding vehicle and the target inter-vehicle distance Ds are compared with the aforementioned (1).
The calculation is performed using the expressions 2) and (13), and the process proceeds to step S407.

In step S407, the relative speed Vr of the preceding vehicle
Is positive or negative. If Vr> 0.0, that is, if the preceding vehicle is moving away from the own vehicle 1, the process proceeds to step S408, and the current inter-vehicle distance Dr is set as described in (14) above.
29 is larger or smaller than the inter-vehicle distance on the boundary line S1 in FIG. 29 calculated by the equation, that is, is classified into the region R1 above the boundary line S1 in FIG. 29 or the region below the boundary line S1. It is determined whether it is classified as R3. If Ds−Vr2 / (2 × Aa) <Dr in step S408, it is determined in step S409 that the state of the preceding vehicle is classified into the region R1 according to the above equations (17) and (18). Calculate the throttle opening Ts and proceed to step S416, where Ds-V
If r2 / (2 × Aa) ≧ Dr, in step S410,
Since the state of the preceding vehicle is classified into the region R3, the throttle opening Ts is fully closed (Ts = 0.0), and the process proceeds to step S416.

On the other hand, in step S407, Vr ≦ 0.
0, that is, when the own vehicle 1 approaches the preceding vehicle, the process branches from step S407 to step S411, and the current inter-vehicle distance Dr is calculated by the aforementioned equation (15). It is determined whether or not the distance is larger than the upper inter-vehicle distance, that is, whether the area is classified into the area R2 above the boundary line S2 in FIG. 29 or the area R3 below the boundary line S2.

As a result, in step S411, Ds-Vr
If 2 / (2 × Ac) <Dr, in step S412, it is determined that the state of the preceding vehicle is classified into the region R2, and the aforementioned (1) is determined.
The throttle opening Ts is calculated by the equation 6), and step S41 is performed.
Proceed to 6 and if Ds−Vr2 / (2 × Ac) ≧ Dr,
In step S413, the state of the preceding vehicle is classified into the region R3, the throttle opening Ts is fully closed (Ts = 0.0), and the process proceeds to step S416.

Then, the above steps S402, S405, S409, S
Step S416 from any of steps 410, S412, S413
When the process proceeds to step (3), the throttle opening Ts calculated in the corresponding step is output to the throttle actuator 3, and the program exits. Thereby, the throttle valve 2 is controlled to a predetermined opening.

On the other hand, with respect to the above throttle control processing,
When the program of the parking brake control process of FIG. 40 is executed in parallel, the parking brake actuator 6 is controlled, and the possibility of an abnormal approach of the inter-vehicle distance to the preceding vehicle is detected in advance, and there is a possibility of abnormal approach. Is alerted.

In this parking brake control process, in step S501, the detected values of the inter-vehicle distance Dr and the relative speed Vr from the preceding vehicle stored in the output memory 115 and the speed Ve of the vehicle 1 from the vehicle speed sensor 8 are calculated. Own vehicle 1 such as detection value
Then, in step S502, the traveling speed VQ, the required inter-vehicle distance Dn, and the warning inter-vehicle distance Dw of the preceding vehicle are input from the input data in step S502, respectively.
When calculated by the equations (19) and (20), step S503 is performed.
Then, it is checked whether or not the current inter-vehicle distance Dr is smaller than the required inter-vehicle distance Dn.

If Dr <Dn in step S503, the parking brake actuator 6 is turned on to activate the parking brake 5 in step S504.
The vehicle 1 is decelerated or stopped. If Dr ≧ Dn, the parking brake actuator 6 is turned off to release the parking brake 5 in step S505.

Then, the process proceeds from step S504 or step S505 to step S506, where the current inter-vehicle distance D
r is compared with the warning inter-vehicle distance Dw. If Dr ≧ Dw, and there is no possibility that the own vehicle 1 will abnormally approach the preceding vehicle, the program exits and Dr <Dw. If there is a possibility of approaching the car abnormally,
Proceeding to S507, an alarm is generated and output to the display 9, and as described above, for example, the position display section 9d of the display 9 is lit in red to warn the driver and urge the operation of the main brake.

[0229]

[0230]

[0231]

[0232] Figure 4 1 to 4 5 relates to a second embodiment of the present invention, FIG 4 1 general block diagram of a distance control device, FIG 2
A circuit block diagram of a distance control device, FIG. 4 3 is an explanatory view showing a method of scanning a laser beam from the side, illustrating 4 4 showing a scanning method of laser beam from the top, 4 5 Laser radar ranging It is explanatory drawing which shows the two-dimensional distribution of the three-dimensional object measured by a unit.

[0233] inter-vehicle distance control device 300B mounted on a vehicle 600 of this embodiment, as shown in FIG. 4 1, with respect to the first embodiment described above, instead of the stereoscopic optical system 10 and the image processing unit 100, A laser projection unit 601 and a laser radar ranging unit 610 are employed as preceding vehicle detection means, and the other configuration is the same as that of the first embodiment.

The laser radar ranging unit 610
Is a device that projects a laser beam, receives light reflected by the laser beam hitting an object, and measures the distance from the required time to the object.A known device can be applied,・ Radar ranging unit 61
The position information of the two-dimensional distribution of the three-dimensional object obtained by 0 can be processed in the same manner as in the first embodiment to control the inter-vehicle distance.

[0235] That is, in this embodiment, the laser projection unit 601 having a scanning function of the projection-receiving a laser beam in the lateral direction is mounted to the front of the vehicle 600, as shown in FIG. 4 2, The laser / radar ranging unit 610 calculates the distance to the object from the time required for projecting and receiving the laser beam, and calculates the two-dimensional position of the object from the direction in which the laser beam is scanned.
0a, the image processing / inter-vehicle distance control computer 110 of the first embodiment is connected to a distance measuring circuit 620 comprising a two-dimensional distribution memory 620b for writing a two-dimensional position of a detected object. The preceding vehicle is detected from the two-dimensional distribution information written in the distribution memory 620b, and the inter-vehicle distance and the relative speed are calculated.

[0236] As shown in FIG. 4 3, wherein the laser beam is projected horizontally from the laser projection unit 601, only the three-dimensional object on the higher road surface position is detected. Further, as shown in FIG. 4 4, the laser beam is scanned in the lateral direction, the operation of the laser beam to detect the distance are the light projecting and receiving every predetermined intervals in a predetermined scanning range is repeated,
A two-dimensional distribution of the three-dimensional object is measured.

For example, when the situation where another vehicle is ahead is measured by the laser radar ranging unit 610, FIG.
The data of the two-dimensional distribution of the three-dimensional object as shown in FIG. 5 is obtained. Therefore, the preceding vehicle can be detected by performing the same object detection processing as in the first embodiment on these data, and the inter-vehicle distance and the relative speed can be calculated.

[0238] In this embodiment, similarly to the first actual施例described above, clumsy brake in a traffic jam during running or the like, it is possible to reduce greatly the opening to the driver burden driver from repeated accelerator operation it can.

[0239]

As described above, according to the present invention, the driver is released from the frequent operation of the accelerator or the brake during a traffic jam or the like, and the inter-vehicle distance with the preceding vehicle is automatically fixed. , The burden on the driver can be reduced , and safety can be improved .

[0240]

[0241]

[Brief description of the drawings]

FIGS. 1 to 40 relate to a first embodiment of the present invention, and FIG. 1 is an overall configuration diagram of an inter-vehicle distance control device.

FIG. 2 is a circuit block diagram of an inter-vehicle distance control device;

FIG. 3 is an explanatory diagram showing a configuration around a parking brake actuator.

FIG. 4 is an explanatory diagram showing a screen of a display.

FIG. 5 is an explanatory view showing the appearance of another display unit.

FIG. 6 is a front view of the vehicle.

FIG. 7 is an explanatory diagram showing a relationship between a camera and a subject.

FIG. 8 is a detailed circuit diagram of the image processor.

FIG. 9 is an explanatory diagram of a city block distance calculation circuit.

FIG. 10 is a block diagram of a minimum value detection circuit.

FIG. 11 is an explanatory diagram showing an example of an image captured by a vehicle-mounted CCD camera;

FIG. 12 is an explanatory diagram showing an example of a distance image.

FIG. 13 is a top view of the vehicle.

FIG. 14 is a side view of the vehicle.

FIG. 15 is a functional block diagram of a computer for image processing and inter-vehicle distance control.

FIG. 16 is an explanatory diagram showing an example of a road model.

FIG. 17 is an explanatory diagram showing the shape of a three-dimensional window.

FIG. 18 is an explanatory diagram showing the shape of a two-dimensional window.

FIG. 19 is an explanatory diagram showing a deviation amount between a linear element and data.

FIG. 20 is an explanatory diagram showing a relationship between a shift amount and a weight coefficient.

FIG. 21 is an explanatory diagram showing an example of a detected road shape.

FIG. 22 is an explanatory diagram showing a method of dividing an image.

FIG. 23 is an explanatory diagram showing a relationship between a detected object and a histogram.

FIG. 24 is an explanatory diagram showing an example of a detection result and a detection distance of an existing area of an object;

FIG. 25 is an explanatory diagram showing the shape of a three-dimensional window for object detection.

FIG. 26 is an explanatory diagram showing the shape of a two-dimensional window for object detection.

FIG. 27 is an explanatory diagram showing an example of data constituting an outline of an object;

FIG. 28 is an explanatory diagram showing an example of a contour image of an object and detected outer diameter dimensions.

FIG. 29 is an explanatory diagram showing the concept of throttle opening determination.

FIG. 30 is a flowchart showing the operation of the image processor.

FIG. 31 is an explanatory diagram showing a storage order in a shift register.

FIG. 32 is a timing chart showing the operation of the city block distance calculation circuit.

FIG. 33 is a timing chart showing the operation of a shift amount determination unit.

FIG. 34 is a timing chart showing the operation of the image processor.

FIG. 35 is a flowchart of a road detection process.

FIG. 36 is a flowchart of a road detection process (continued).

FIG. 37 is a flowchart of an object detection process.

FIG. 38 is a flowchart of an object detection process (continued).

FIG. 39 is a flowchart of a throttle control process.

FIG. 40 is a flowchart of a parking brake control process.

[41] Figure 4 1 to 4 5 relates to a second embodiment of the present invention, the overall configuration diagram in FIG. 4. 1 inter-vehicle distance control device

FIG. 42 is a circuit block diagram of an inter-vehicle distance control device.

FIG. 43 is an explanatory view showing a laser beam scanning method from the side.

FIG. 44 is an explanatory diagram showing a laser beam scanning method from above.

FIG. 45 is an explanatory diagram showing a two-dimensional distribution of a three-dimensional object measured by a laser radar ranging unit.

[Explanation of symbols]

 Reference Signs List 10 stereo optical system (preceding vehicle detecting means) 100 image processing unit (preceding vehicle detecting means) 200 inter-vehicle distance control unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-11523 (JP, A) JP-A-5-225498 (JP, A) JP-A-63-180531 (JP, A) JP-A-5-215 262164 (JP, A) JP-A-5-274036 (JP, A) JP-A-2-95931 (JP, A) JP-A-6-305340 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G08G 1/00-1/16 B60K 31/00 G05D 1/02 B60R 21/00 610

Claims (1)

(57) [Claims] A preceding vehicle detecting means for detecting a preceding vehicle existing in the traveling direction of the own vehicle and calculating a distance between the preceding vehicle and the own vehicle and a relative speed of the preceding vehicle to the own vehicle, and an engine.
By driving the throttle valve of the
A first control device for performing speed control, and a parking brake
The actuator is driven by an actuator to control deceleration and stop.
In vehicle and a second control device for performing control to set the target inter-vehicle distance based on the speed of the own vehicle, the inter-vehicle distance and the relative speed calculated by the preceding vehicle detection means
Select one of the first and second control devices, and
Inter-vehicle distance control to keep the inter-vehicle distance at the target inter-vehicle distance
And when the speed is below the desired speed, the slot of the first control device
Deceleration control or stop control when the
When it is determined that control is necessary, the second control device is used.
And an inter-vehicle distance control device for performing control.