JPS59197816A - Inter-vehicle distance detecting device - Google Patents

Abstract

PURPOSE:To make only a vehicle an object, and to detect an inter-vehicle distance to it by discriminating plural vehicle feature data stored in advance and the present video signal, and detecting a distance to a vehicle existing in a prescribed direction of the utside of the vehicle. CONSTITUTION:An electric operation processor 2 inputs a video signal from two TV cameras 3a, 3b adjusted so that optical axes become parallel, operates an inter-vehicle distance to a preceding vehicle 6, displays a result on a display 4, and controls a driving system from a relation to its own car speed by a signal from a speed sensor 5. The car speed sensor 5 is constituted of a multipole magnet 51 rotated by a wheel driving shaft and a reed switch 52 which is turned on and off by a rotation of this magnet 51. Also, on and off of this reed switch 52 are converted to on and off pulses by a waveform shaping circuit 28, and provided to a CPU26. In the CPU26, its pulse interval is measured, and a car speed is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inter-vehicle distance detection device that detects the distance to a vehicle in a predetermined direction outside the vehicle, for example, to a vehicle in front.

Conventionally, in this shield device, waves such as electromagnetic waves and ultrasonic waves are emitted into the space in front of the vehicle to detect the distance to the vehicle in front of the vehicle.

However, this method has a problem in that if a vehicle equipped with a device of the same type is nearby, interference may occur due to the influence of waves from other vehicles, resulting in erroneous detection.

The present invention was made in response to the above problem, and its purpose is to avoid emitting waves like the above ones,
To provide an inter-vehicle distance detection device which passively detects light to detect an inter-vehicle distance and does not cause false detection even if a vehicle equipped with the same type of device is nearby.

Therefore, as shown in FIG. 1, the present invention provides a first camera which is spaced apart and which photographs a predetermined direction outside the vehicle. a second optical-to-electrical conversion means A, B; A first storage unit C that stores the video signals obtained by the second optical-to-electrical conversion units A and H, and a storage unit ff12 that stores a plurality of vehicle characteristic data corresponding to a plurality of types of vehicles in advance. The video signal stored in the first storage means C is inputted, the video signal is converted according to predetermined characteristic parameters, and the converted data and the second record tt are input.
a determining means E that compares a plurality of vehicle characteristic data stored in the means and determines whether or not No. 12 indicating a vehicle image is included in the video signal;
When it is determined that a signal representing a vehicle image is included, it is determined by how much the determined signal representing a vehicle image differs between the two video signals stored in the first storage means C. The present invention is characterized by comprising a calculation means F for calculating whether the vehicle is present and thereby detecting the distance to the vehicle existing in a predetermined direction outside the vehicle.

However, since the present invention is configured as described above, erroneous detection may occur due to the presence of other devices of the same type.
The present invention has an excellent effect in that it is possible to detect the inter-vehicle distance of only the vehicle without erroneously detecting the inter-vehicle distance to objects such as guardrails other than the vehicle.

The present invention will be described below with reference to embodiments shown in the drawings. Second
The figure is a schematic overall configuration diagram of one embodiment. This second
In the vehicle 1 shown in the figure, 3a.

Reference numeral 3b denotes two TV cameras that are mounted vertically apart and adjusted so that their optical axes are parallel, and the electrical processing unit 2 receives video signals from the TV cameras 3a and 3b. , calculates the inter-vehicle distance to the preceding vehicle 6, displays the result on the display 4, and displays the result on the speed sensor 5.
The drive system (not shown in FIG. 2) is controlled based on the relationship between the speed of the vehicle and the speed of the vehicle. In addition, 7
shows the field of view of the two TV cameras 3a and 3b.

The drive system control mechanism includes a throttle opening adjustment mechanism as shown in Fig. 3 and a brake pressure 1 as shown in Fig. 1n4.
It is equipped with an 11fi machine ellipse. In figure ff13, 31
is an actuator that uses engine intake pipe negative pressure as its operating force, and the pressure is adjusted by a VSV (vacuum switching valve) 32 to control the throttle opening. In this embodiment, the throttle opening is automatically controlled. 11
11, the link system is configured such that the opening can be controlled by the accelerator pedal 33. f
In FIG. 4 m magnetic valves 44-47
adjusts the discharge pressure from the hydraulic pump 43 to fully operate the control cylinder 42. When the brake operation is not automatically controlled, the brake pedal 48 and the mask cylinder 49 constitute a mask cylinder hydraulic circuit such that the brake operation nJl is performed.

As shown in FIG. 5, the vehicle speed sensor 5 in FIG. Then, turning on this reed switch 52,
Waveform off! ! The signal is converted into an on/off pulse by a circuit 28 and applied to the CPU 26. And C.P.
U26 measures the nine corners of the pulse to detect the vehicle speed.

FIG. 6 is an electrical wiring diagram showing the electrical wiring part of this embodiment, in which the one-dimensional image value numbers from the TV cameras 3a and 3b are
D conversion! 1i8a, 8b rA/D conversion, memory (
-@ plane is stored as a two-dimensional array of digital values on RAM) 9a and 9b. In the electrical arithmetic device 2, 21.
24 is a ROM, which stores programs for the CPUs 23 and 26, respectively. 22.25 is RAM, CPU23
, 26 are temporarily stored.

23.26 is cpυ and the 9th v4. The arithmetic processing shown in FIG. 10 is executed. 27 is an A/D lock changer that converts an analog signal from the throttle opening sensor 11 into a digital signal. A waveform shaping circuit 28 shapes the waveform of the signal from the vehicle speed sensor 5.

A throttle opening sensor 11 detects the opening of the throttle valve using a potentiometer and generates an analog signal corresponding to the opening. Reference numeral 12 denotes a speed setting device, which is used to set a set speed using constant speed running control, and generates a digital signal according to the set value. Reference numeral 13 denotes an AUTO switch, which is of a closed-hold type and is closed when driving at a constant speed or following a vehicle in front.

Reference numerals 30 and 40 are a throttle opening adjustment mechanism and a brake pressure adjustment mechanism, the detailed construction of which is shown in FIGS. 3 and 4. 4
The display shows the actual distance to the vehicle in front and the safe distance based on the speed of your own troops. Reference numeral 10 is a buzzer, which makes a buzzer sound for a certain period of time in response to a buzzer-on command from the CPU 2G.

Figure 7 shows the storage method of M9a to R;
Storage areas are secured from a predetermined address by the number of tlRJR obtained by D conversion, and the areas are subdivided for each data in the vertical direction. The A/D conversion value of the corresponding video data is input to each storage unit, and serves as luminance information of each target point. In the figure, one square corresponds to one pixel.

That is, FIG. 7 shows that one screen data is stored as a two-dimensional array by digitally converting the brightness in each direction of the front space and inputting it into the corresponding storage unit. Furthermore, the video data from the other TV camera 3b is also stored in another data area in the RAM 9b as a two-dimensional array as shown in FIG.

The operation of the above configuration will be explained. Now, in a vehicle equipped with the various components shown in FIG. 6, when the vehicle key is turned in at the start of operation, each electrical system is activated by receiving power from the vehicle battery.

In this operating state, first, the detection of the inter-vehicle distance and the relative speed detection with respect to the preceding vehicle by the CPU 23 will be explained.

Figure 9 shows the flow of the third floor of the CI' U 23 process.

It is a diagram. In this FIG. 9, step 100 is CP
This is a step for initializing the registers, counters, etc. of [No. 23].

Next, the process proceeds to step 101, where it is determined whether or not the actual 11th hour has arrived, and the process is in a standby state until the execution time has arrived. An internal timer is used to count this execution time. By using this step of determining the execution time, it is possible to keep the calculation cycle from the steering knobs 102 to 116 constant.

If the determination in step 101 is YES, step 10
Proceed to step 2. In this step knob 102, the video data of M9a is manually input to the stored R as shown in FIG. Here, the input order is to input the vertical data sequentially from the data at address Δ+n-1 to the data at address Δ+n-1, and then input the vertical data again sequentially from the data at address -n. Similarly, step 10
3, the video data stored in the RAM 9b as shown in FIG. 8 is input sequentially to address B-i3+n-1it, address B+n-, and so on.

Next, in step 104, the video data input in steps 102 and 103 are processed to extract the contours, which are binary values.
Generate image data. Generally, there is a change in brightness (brightness) between objects that exist in the space in front of the vehicle and the background.
The contour of the object can be detected by differentiating the two-dimensional array of luminance data in a plane.

Next, in step 105, the two binarized image data are compared element by element, and matching parts are removed. This process is to remove objects that are sufficiently far away from the video data, and between the two video data of the TV camera 3as3b whose optical axes are adjusted parallel and are spaced apart by a distance of 1111, The images of objects that are sufficiently far away compared to l take advantage of the fact that they overlap in position. FIG. 11 shows an example of a binary image data array subjected to # processing, and shows a case in which the data is retransmitted as an image.

This binary image containing only outlines includes various closed figures such as vehicles, guardrails, center lines, etc., and these closed figures are detected in step 106.

Then, in steps 107 and 108, the object that generated the closed figure is determined using feature parameters to be described later. This determination method is shown below. First, numbers i are individually assigned to various feature parameters, and the It difference function E (
Define i).

E (+) = l (X (i) −X (i))/X
(i) ) 2X(i): Measured value for feature parameter i X(i): Average value for feature parameter i Also, as the feature parameter, the following items are used.

i-1: Ratio of the sides of the rectangle circumscribing the closed figure.

(Ratio of lengths a and b shown in Figure 12) i-2: ratio of the area of the closed figure to the area of the circumscribing rectangle.

(If the area of the closed figure is Sn in Figure 13, then Sn/
(axl)). ) i = 3.4 + Relationship between the area center position of the closed figure and the sides of the circumscribed rectangle (a'/a and b'/b in Figure 12) l-
58 Ratio between the area of a closed figure and the area of a circle circumscribing the closed figure centered at the area center position.

(Sn/gr2 in Figure 13) i=6: ratio of area to perimeter of closed figure.

Note that the length of the sides, the area center position, etc. are defined by the number of pixels.

The electrical processing unit 2 stores average values for each feature parameter of various objects in the ROM 21. In this embodiment, the various objects are center lines and side lines drawn on the road.

Guardrail, vehicle type 1 (light vehicle), vehicle type 2 (normal passenger car), vehicle type 3 (large truck),
Vehicle type 4 (large bus), vehicle type 5 (two-wheeled vehicle), etc. are targeted, and average values for characteristic parameters are stored for each object. Further, in this embodiment, characteristic parameters are set mainly based on ratio information regarding images so that the object can be identified regardless of distance. The closed figure detected in FIG. 11 has its features measured for each feature parameter item i, and its error function E(
i) is calculated.

Next, in step 109, for each target object, the error function E
(i) is multiplied by the weighting function W (1), further added and averaged to calculate the error determination value ERRj. suffix j
distinguishes the target object. Then, in the next step 110, if the error determination value is less than a certain amount, it is assumed that the features match, and the image and object are associated.

Then, in step 111, it is determined whether a vehicle is included in the matched objects.

If a vehicle is included, the determination becomes YIES, and the process proceeds to step 112. In this step 112, for the image determined to be a vehicle, two television cameras 3a
, 3b is used to detect the distance. The fS14 diagram shows the principle, and two TVlyfi93m
, 3b were separated by 11 ml in the vertical direction, and the optical axes were adjusted to be parallel. The distance to the representative point of a pair of objects (for example, the center of area of a closed figure) is determined by the angles α and β between the line segment connecting the representative point and the center of the TV camera and the center axis of the TV camera, and the distance W11 between the two TV cameras. From this, it can be determined as LmJ/(tanβ-tanα). The angles α and β can be calculated from the representative point positions in the upper and lower image data.

Next, the process proceeds to step 113, where a preceding vehicle flag indicating detection of a preceding vehicle is set, and the process proceeds to step 115.On the other hand, when the determination in step 111 is NO, step 11
The preceding vehicle flag is reset in step 4, and then step 11
Proceed to step 5.

In this step 115, when the preceding vehicle flag is set, the vehicle distance ff1llll calculated in step 112 is
The relative speed to the preceding vehicle is calculated using L.

In this relative speed calculation, since inter-vehicle distance am detection is performed at a fixed period, the previous inter-vehicle distance Lo and the current vehicle same-level 1elL are calculated.
This is done using the difference between the distance and the amount of change in distance. After completing this relative speed calculation, the current inter-vehicle distance ML is stored as the previous inter-vehicle distance.

Note that when the preceding vehicle flag has been reset, the previous inter-vehicle distance 1alLo is set to 0. Then, when the previous inter-vehicle distance lit L o is 0, when this step 115 is reached after passing through steps 112 and 113 (when the leading vehicle flag is set), the current inter-vehicle distance ML is assumed to have arrived for the first time. is stored as the previous inter-vehicle distance jelLo.

In the next step 146, the calculated 1n information, that is, the setting and resetting of the preceding vehicle flag, and when the preceding vehicle flag is set, the inter-vehicle distance and relative speed are calculated by CP.
Transfer to U26.

The above-described process is repeatedly executed at regular intervals to detect the vehicle III distance and relative speed from the preceding vehicle.

In addition to the CPL 123, the electrical fraud processing unit w2 includes:
It is equipped with another CPU 26. This CI) U
2G inputs preceding vehicle information calculated by the CPU 23 and performs display, warning, and control of the drive system. The processing will be described below.

FIG. 10 is a calculation flowchart showing the calculation processing of the CPU 26. In this FIG. 1o, first, in step 200, C
PU26 register and counter.

After initializing latches and the like, the process proceeds to step 201, where the preceding vehicle information transferred from the CPU 23 (transferred at step 116 in FIG. 10) is manually processed.

After inputting the preceding vehicle information, the process proceeds to step 202 and calculates the speed of the own vehicle. This speed calculation is performed by measuring the interval at which pulses are generated from the waveform shaping circuit 28. Note that if no pulse is generated within a predetermined time, the vehicle speed is set to 0. Next, the process proceeds to step 203.
Based on information from the CPU 23, it is determined whether the preceding vehicle flag is set.

If the preceding vehicle flag is set, the determination becomes YES, and the process proceeds to step 204, where a safe inter-vehicle distance is calculated. This safe distance II! The distance is falsified by the own vehicle speed calculated in step 202 and the relative speed with respect to the preceding vehicle calculated by the CPU 23. In other words, the ROM 24 in the turtle trick processing device 2 stores in advance a characteristic map showing the jump N;
A safe inter-vehicle distance is determined based on the own vehicle speed calculated in , and this safe vehicle IJI distance M is corrected based on the relative speed with respect to the preceding vehicle Jli. This correction is applied when the relative speed to the preceding vehicle is positive.
In other words, when you are in a situation where you can avoid the vehicle in front, the safe vehicle distance is 1llll.
When the relative speed to the preceding vehicle is negative, that is, the vehicle is approaching the preceding vehicle, the safe inter-vehicle distance is shortened. Then, in step 205, a command is generated on the display 4 to display the safe inter-vehicle distance and the screen of the inter-vehicle distance with the preceding vehicle on the display 4.

Next, in step 206, it is determined whether the inter-vehicle distance to the preceding vehicle is equal to or greater than the safe inter-vehicle distance. Distance between the vehicle in front and the vehicle in front
If the li distance is shorter than the safe following distance, the ↑ setting is No.
become. At this time, the control proceeds to the steering knob 211 and generates a buzzer-on command to the buzzer 10 to issue a warning, and proceeds to step 212 to determine whether or not the AUTO switch 13 is turned on. , if the AUTO switch 13 is not turned on, the determination becomes No and the process returns to step 201. Therefore, as long as the distance to the preceding vehicle is shorter than the safe distance, the above process is repeated.
The inter-vehicle distance and safe inter-vehicle distance to the preceding vehicle are displayed on the display 4, and a buzzer is sounded for a certain period of time to issue a warning.

Further, when the inter-vehicle distance to the preceding vehicle is equal to or greater than the safe distance ll1a, the determination in step 206 becomes YES, and the process returns to step 201 via step 208.

Further, if there is no preceding vehicle and the preceding vehicle flag has been reset and the determination at step 203 is No, the process proceeds to step 207, where a command to erase the display 4 is issued to the display 4, and step 20B is executed. The process then returns to step 201.

On the other hand, when the AUTO switch 13 is engaged to drive at a constant speed and follow the vehicle in front, step 20
When step 208 is reached via step 6 or 207, the determination becomes YES. Then, the process proceeds to step 209, where the data of the set speed set on the speed setter No. 12 is input, and the process proceeds to step 210, where the throttle valve is opened so that the own speed approaches the set speed input in step 209. Control the degree. That is, step 202
The target throttle relation is determined according to the deviation between the own speed calculated in A control amount is determined, and a control electric signal having a duty ratio corresponding to the control amount is generated to the VSV 32 in FIG. Therefore, by executing the above process, the vehicle speed can be automatically maintained at the set speed.

In this state, if there is a preceding vehicle and the inter-vehicle distance to the preceding vehicle becomes shorter than the safe inter-vehicle distance, the process proceeds from step 206 to step 213 via steps 211 and 212, and the throttle opening sensor 11 performs A/D conversion. Vessel 27
It is determined whether the throttle valve is fully closed or not from the value of the throttle opening via the throttle opening. Then, when the throttle valve is not fully closed, the determination becomes NO and step 2
a control electrical signal proceeding to step 14 to close the throttle valve;
That is, a signal for opening the VSV 32 to the atmosphere in FIG. 3 is generated in the VSV 32, and then the process returns to step 201.

Therefore, when the AUTO switch 13 is turned on, the car 'B1Ir! When the distance between the chicks becomes shorter than the safe following distance, the above process is executed, a warning is given by the buzzer, and the throttle valve is gradually closed.

After that, even if the throttle valve is fully closed, if the distance between the vehicle and the preceding vehicle does not become 1IIJ2J above the safe distance, the process proceeds from step 213 to step 215, where a control electric signal (predetermined duty ratio) is applied to apply a predetermined brake pressure to the wheels. on,
OFF signal) is generated to the solenoid valves 44 to 47 in FIG. 4, and then the process returns to step 201. Therefore, it is possible to forcibly apply the brakes to make the distance between the vehicle and the preceding vehicle greater than or equal to the safe distance.

If the distance between the vehicle and the preceding vehicle is equal to or greater than the safe distance, steps 206 to 208 are performed, and step 209 is reached.
．． The arithmetic processing of step 210 is executed, and constant speed running control is performed so that the speed of the own army approaches the set speed.

Therefore, by executing the above process, if there is no preceding vehicle, the vehicle can travel at a constant speed, and if there is a preceding vehicle, the vehicle can follow the preceding vehicle while maintaining a safe inter-vehicle distance.

In the above embodiment, two TV cameras are installed above and below, but they are installed on the left and right, and the image scanning direction is not vertical but horizontal to detect the distance between the vehicle and the vehicle ahead. It's okay.

In addition, we have shown a device that detects the distance between the vehicle in front and the vehicle in front.
The distance between the vehicle and the following vehicle may also be determined.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the structure of the present invention, Fig. 2 is a schematic overall block diagram of an embodiment of the present invention, Fig. 3 is a detailed block diagram of the throttle opening adjustment mechanism, and Fig. ff14 is a brake pressure FIG. 5 is a detailed configuration diagram of the adjustment mechanism, FIG. 5 is a detailed configuration diagram of the vehicle speed sensor, FIG. 6 is an electrical connection diagram showing the electrical connection part of this embodiment, and FIG.
FIG. 8 is an explanatory diagram showing the storage system of RAMs 9a and 9b, and FIG. FIG. 1θ is a computation flowchart showing the computation processing of the CPU 23, 26, and FIGS. 11 to ff114 are explanatory diagrams for explaining the operation. 2... Electrical processing unit, 3a, 3b... TV camera, 4... Display. Representative Patent Attorney Takashi Okabe Fig. 1 A Fig. 3 Fig. 4 Fig. 11 Fig. 14 Section

Claims (1)

[Claims] A first and a second camera are arranged apart from each other and photograph a predetermined direction outside the vehicle.
)shi-1 Ki! & l! ! ! 3J' stage and this 1st stage.
a first storage means for storing the video signal obtained by the second optical-to-electrical conversion means; a second storage means for storing in advance a plurality of vehicle characteristic data corresponding to a plurality of types of vehicles; The video signal stored in the first storage means is input, the video signal is converted according to predetermined characteristic parameters, and the converted data and the plurality of data recorded in the second storage means are input. The image is compared with the vehicle characteristic data of When it is determined that the signal representing the image of the vehicle is included, it is calculated how much the signal representing the image of the vehicle determined is different among the two video signals stored in the first storage means, and based on this, An inter-vehicle distance detection device comprising: a calculation means for detecting a distance in front of a vehicle existing in a predetermined direction outside the vehicle.