JPH08202998A - Lane deviation alarm device - Google Patents

Abstract

PURPOSE: To generate a stain detection alarm only when the detection performance of an image pickup sensor is lowered without requiring a new additive for stain detection by counting the number of times of loop in which a lane detection can not be performed within a prescribed time and energizing a different alarm means because a stain a sensor occurs when this number of times exceeds a threshold. CONSTITUTION: An image processor 4 detects the lane on a road by binarizing the image signal obtained from an image pickup sensor 1. When the lane detection can not be performed in the one loop in a program routine because this image processor 4 uses the processing program, a lane detection error is regarded to be generated and the number of times of this error is counted. When this number of times exceeds a threshold within a prescribed time, the stain of the image pickup sensor 1 is regarded to be generated and an alarm is generated by energizing the alarm means 6 which is different from the alarm means 5 of a lane deviation. Therefore, the lowering of the detection force due to the stain of a lens surface can be detected without an addition product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lane departure warning system, and more particularly to a lane (white line or yellow line) of a vehicle by monitoring the road surface condition in front of or behind the vehicle with an image sensor.
The present invention relates to a device that warns of deviation from.

[0002]

2. Description of the Related Art Conventionally, a convex portion is intermittently embedded in a lane on a road surface, and when a vehicle accidentally steps on the convex portion due to a sideways driving or a drowsiness driving, a driver is struck by vibration or muffled noise. Methods of warning lane departure are known.

However, such a method has the drawback that it must be installed on all roads, is inefficient, and that it has not been installed on highways leading to major accidents. Further, when the tire steps on the lane and notices danger due to vibration, the rearview mirror and the fender have already entered the adjacent lane and may come into contact with the adjacent vehicle.

Therefore, recently, there has been proposed a device which detects an lane by using an image sensor (line TV camera) for photographing the front or the rear of the vehicle and warns the deviation of the lane as soon as possible.

FIG. 4 shows an example of the structure of such a conventionally known lane departure warning device. In the figure, 1 is an image sensor, 2 is a winker, 3 is a vehicle speed sensor, and 4 is an image of these. The image processing device receives output signals from the sensor 1, the winker 2, and the vehicle speed sensor 3 and gives a control signal to the alarm means 5.

In the operation of such a lane departure warning device, first, the image processing device 4 is initialized, and then the image signal from the image sensor 1, the winker signal from the winker 2 and the vehicle speed from the vehicle speed sensor 3 are used. Input the signal.

Then, the image processing device 4 first binarizes the image signal obtained from the image sensor 1 to obtain the binary signal.
The lane on the road surface on which the vehicle is traveling is extracted based on the result of the binarization process, and the position of the vehicle with respect to this lane is calculated.

Then, the relative positional relationship between the lane and the vehicle calculated in this way is stored in advance or determined by various input setting data, and the vehicle is in a state of deviating from or likely to deviate from the lane. When the determination is made, the image processing device 4 activates the warning means 5 to give the lane departure warning when the direction instruction signal is not given from the winker 2 and the vehicle speed signal from the vehicle speed sensor 3 exceeds the threshold value. Emit.

The relative positional relationship between the lane and the vehicle described above is
As shown in the side view shown in FIG. 5A and the plan view shown in FIG. 5B, the mounting height H of the image sensor 1 mounted on the roof of the vehicle cab 10 and directly below the image sensor 1. From the vehicle to the predetermined detection position A on the road surface, the vehicle width VW, the lane width LW, and the horizontal angle of view θ of the image sensor 1. The lane departure can be detected even in the relative position.

[0010]

In such a conventional lane departure warning device, there is a problem that dirt on the lens surface due to rain or dust in the optical system of the image sensor leads to deterioration in detection performance.

On the other hand, the conventional method is disclosed in JP-A-60-149.
As disclosed in Japanese Patent Publication No. 984, there is devised a technique for irradiating a lens with a dirt detection laser or the like and determining the degree of dirt of the lens by the reflected light. In such a case, a dirt detection laser is used. However, in order to be able to detect dirt in the required range of the lens surface at the same time, it is necessary to secure a space such as a laser optical system for dirt detection. On the contrary,
In fact, there were also problems such as detecting dirt that had little effect.

Therefore, an object of the present invention is to provide a lane departure warning device which does not require a new additional object for detecting dirt and can issue a dirt detection warning only when the detection performance of the image sensor is deteriorated. And

[0013]

In order to achieve the above object, a lane departure warning system according to the present invention includes an image sensor mounted on a vehicle roof, a means for generating a vehicle directional signal, and a warning means. If the lane on the road surface is detected by binarizing the image signal obtained from the image sensor, and the deviation of the vehicle from the lane is detected, the warning signal is generated if the directional signal is not generated. An image processing device for activating the means is further provided, and the image processing device counts the number of loops in which the lane cannot be detected in the processing program routine within a predetermined time, and the number of times exceeds the threshold value. Sometimes, it is characterized in that another alarm means is energized on the assumption that the sensor is soiled.

Further, according to the present invention, a vehicle speed sensor is further provided, and the image processing apparatus detects the lane departure only when the vehicle speed detected by the vehicle speed sensor continues to exceed the threshold value for the predetermined time. Good.

[0015]

In the present invention, the image processing apparatus detects the lane on the road surface by binarizing the image signal obtained from the image sensor. Since this image processing apparatus uses a processing program, 1 in the program routine
When the lane cannot be detected in the loop, a lane detection error is counted and the number of errors is counted. When this number exceeds a threshold within a predetermined time, the image sensor is contaminated and a lane departure warning is issued. The alarm is generated by activating an alarm means other than the means.

In this case, a vehicle speed sensor may be provided to measure the above predetermined time, and the time during which the vehicle speed detected by this vehicle speed sensor exceeds the threshold value may be set as the predetermined time. It is possible to activate the above-mentioned other warning means when the lane cannot be detected for a predetermined time in the vehicle traveling on the road surface where is clearly drawn.

[0017]

1 shows the configuration of a lane departure warning system according to the present invention, which is different from the conventional configuration example shown in FIG. 4 in that a warning means 6 is newly provided. There is.

FIG. 2 shows an overall processing flow chart of the image processing apparatus 4 in the lane departure warning system having the configuration shown in FIG. 1. Hereinafter, the lane departure warning system according to the present invention will be described with reference to this flow chart. The operation of this embodiment will be described.

First, the image processing apparatus 4 performs initialization (step S1), and then inputs the image signal from the image sensor 1, the winker signal from the winker 2 and the vehicle speed signal from the vehicle speed sensor 3 (step S2). ).

Then, the image signal obtained from the image sensor 1 is binarized (step S3), and it is determined whether or not the lane on the road surface on which the vehicle is traveling can be detected based on the binarization processing result. The determination is made in the same manner as the conventional one (step S4).

If the lane cannot be detected in step S4, the lane detection error plug LEF is set up (step S5), and the process proceeds to step S8.

When the lane can be detected in step S4, the lane detection error plug LEF is lowered (step S6), and the lane coordinates and the lane-vehicle distance are obtained (step S7).

In step S8, it is determined based on the output of the vehicle speed sensor 3 whether or not the current vehicle speed is equal to or higher than a set value. When it is determined that the vehicle speed is equal to or lower than the set value, the vehicle speed flag SPF is lowered (step S9). ).

Whether or not the vehicle speed exceeds the set value is determined because, when the vehicle speed is equal to or lower than the set value, the vehicle is often traveling on a low speed road where the lane is not clear. This is to exclude the case.

When it is found in step S8 that the vehicle speed exceeds the set value, the vehicle speed flag SPF is set (step S10).

Then, it is determined whether or not the lane-vehicle distance obtained in step S7 has become 0 or less (step S1).
1) If it is determined that the turn signal is 0 or less, it is determined from the output of the turn signal 2 input in step S2 whether or not the turn signal is operated (step S12). If the turn signal is not operated, the vehicle is unconscious. The lane departure warning is generated by activating the warning means 5 as if the vehicle is deviating from the lane (step S13).

If the lane-to-vehicle distance is greater than 0 in step S11, or if it is determined in step S12 that the turn signal has been operated, or if an alarm is issued in step S13, the process goes to step S2. Returning to that, the dirt detection subroutine (step S20), which is a feature of the present invention, is executed on the way.

FIG. 3 is a flow chart specifically showing this dirt detection subroutine S20.
First, it is determined whether or not the vehicle speed flag SPF is set (step S21).

As a result, if it is determined that the vehicle speed flag SPF is not set, the process proceeds to step S29, but if the vehicle speed flag SPF is set, the loop counter LC is set.
Is incremented (step S22).

Further, the above steps S5 and S6.
It is determined whether or not the lane detection error flag LEF processed in step S23 is raised (step S23). If the lane detection error flag LEF is lowered, the process proceeds to step S25, but if it is set, the lane detection error counter EC is reached. Is incremented (step S24).

Then, it is judged whether or not the loop counter LC incremented in the above step S22 exceeds a constant A (step S25).

In this case, the constant A is a constant for determining the unit of the dirt detection sampling time during which the alarm device is operating.

In step S25, the loop counter L
When the value of C does not exceed the constant A, the process returns to the flowchart of FIG. 2, but when it is found that the value of the constant A exceeds the constant A, it is determined whether the error counter EC incremented in step S24 exceeds the constant B. The determination is made (step S26).

This constant B is a constant for determining at what rate the white line detection error has occurred during the sampling time.

As a result, when it is determined that the counter EC does not exceed the constant B, the process proceeds to S29, but when it is determined that the counter B exceeds the constant B, a dirt detection flag is set (step S27) and the alarm means 6 is activated. By urging, a dirt alarm is generated (step S28) and the dirt detection flag is lowered.

Then, in step S29, the counters LC and EC are cleared and the process returns to the flowchart of FIG.

Therefore, since the loop counter LC is cleared when the vehicle speed flag SPF is lowered in step S21, the loop counter LC is cleared while the vehicle speed flag SPF is raised.
It is necessary that C ≧ A.

For example, when one loop processing time of the main program routine of the image processing apparatus 4 is 100 msec,
Sampling time is 100msec if constant A = 450
× 450 = 45 seconds, and when traveling at 80 km / h, the traveling distance is equivalent to 1 km, so this distance is 80 or more.
When traveling at Km / h, that is, at a predetermined sampling time of 45 seconds, it is determined in step S26 whether EC ≧ B.

If the dirt detection flag is set when the lane detection error exceeds 70% for this distance of 1 km (45 seconds), the constant B = 450 × 70% = 315. Such constants A and B can be obtained by a running test.

Although the dirt detection flag is held once in step S27, it can be set or reset depending on the determination in step S26.

In the above embodiment, when counting the number of times the lane detection error occurs for each loop, this counting time is processed together with the time when the vehicle speed exceeds the set value. In the present invention, since it is not an essential element that the vehicle speed exceeds the set value, the predetermined time can be set by counting the fixed time with another counter regardless of whether the vehicle speed exceeds the set value. May be specified.

[0042]

As described above, according to the lane departure warning apparatus of the present invention, the image processing apparatus counts the number of loops in which the lane cannot be detected in the processing program routine within the predetermined time, and this number is the threshold value. When it exceeds the limit, it is configured to issue an alarm as if the sensor is contaminated, so it is possible to detect a decrease in the detection power due to contamination of the lens surface of the image sensor without any add-on, saving space. The cost can be reduced and the lens cleaning can be performed at the minimum necessary time.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a lane departure warning device according to the present invention.

FIG. 2 is a flowchart (overall view) of a processing program executed by the lane departure warning apparatus according to the present invention.

FIG. 3 is a flowchart showing a stain detection subroutine of the present invention included in the flowchart of FIG.

FIG. 4 is a block diagram showing a configuration of a conventional lane departure warning device.

FIG. 5 is a schematic image view of a vehicle equipped with an image sensor used for a lane departure warning device as viewed from a side surface and a plane surface.

[Explanation of symbols]

 1 image sensor (line TV camera) 2 winker 3 vehicle speed sensor 4 image processing device 5, 6 alarm means 10 vehicle cab 11, 12 lane

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Claims (2)

[Claims] 1. A lane on a road surface by binarizing an image sensor mounted on a vehicle roof, a means for generating a vehicle direction indicating signal, an alarm means, and an image signal obtained from the image sensor. And an image processing device for activating the warning means if the directional signal is not generated when the departure of the vehicle from the lane is detected, the image processing The device counts the number of loops in which the lane cannot be detected in the processing program routine within a predetermined time, and when the number exceeds the threshold value, another alarm means is activated as the sensor is contaminated. Lane departure warning device characterized by: 2. A vehicle speed sensor is further provided, and the image processing apparatus performs lane departure detection only when the vehicle speed detected by the vehicle speed sensor continues to exceed a threshold value for the predetermined time. The lane departure warning device according to Item 1.