KR100845951B1 - Collision avoidance system for detecting the blind spot of vehicle - Google Patents

Abstract

An anti-collision system for detecting a dead zone of a vehicle is provided to reduce external noise and to detect road environment by using an infrared sensor having high efficiency. An anti-collision system for detecting a dead zone of a vehicle comprises a tail light detection unit(10), a CCD camera unit(20), a steering angle detection unit(30), an infrared sensor unit(40), an alarm unit(50) and a control unit(60). The tail light detection unit detects the on/off status of a tail light. The CCD camera unit photographs road environment and outputs data thereof. The infrared sensor unit detects obstacles provided in the dead zone of the vehicle. The control unit operates the alarm unit to raise an alarm when the obstacle is detected by the infrared sensor unit.

Description

COLLISION AVOIDANCE SYSTEM FOR DETECTING THE BLIND SPOT OF VEHICLE}

1 is a view showing the area that can be understood by the driver by the conventional side mirror and the blind spot area caused by the side mirror or the visual limitation of the driver.

2 is a configuration diagram of a blind spot detection system of a conventional vehicle.

Figure 3 is a flow chart illustrating a blind spot detection process of a conventional blind spot detection system.

Figure 4 is a block diagram of a collision avoidance system through the blind spot detection of the vehicle according to the present invention.

Figure 5 schematically shows a circuit of the infrared sensor means according to the present invention.

6 is a flowchart illustrating a blind spot detection process of the collision avoidance system through blind spot detection of a vehicle according to the present invention.

* Explanation of symbols on main parts of the drawings *

10. Direction indicator light detection means 20. CCD camera means

30. Steering angle detection means 40. Infrared sensor means

50. Alarm means 60. Control means

210. Receiver 220. Image sensor

230. A / D converter 240. Central processing unit

250.Memory 410.IR Sensor

412. Light emitting diode 412a. Registration lens

414. Light Transistor 420. Transmission Control Unit.

422. AVR 430. Receiving Control Unit

432. Preamplifier 434. Tone Decoder

510. Warning light 520. Speaker

610. Microprocessor

The present invention relates to a collision avoidance system by detecting a blind spot of a vehicle, and more particularly, to detect a blind spot and to inform the driver of a blind spot even when changing lanes without turning on a direction indicator. The present invention relates to a collision avoidance system through blind spot detection of a vehicle.

The most obvious evidence is the development of a good engine, which is the heart of the automobile industry. Of course, many factors, such as increased fuel economy and environmental pollution, are considered, but the most important concern is that a vehicle with a good engine is operated for a long time in various environments at high speed. The speed of the car is getting faster with the engine being developed, and at the same time, consumers are demanding a safer car.

Automobile safety devices have been developed through the utilization of assistive devices to protect people from collisions with structural factors such as mandatory installation of air bags, mandatory seat belts, and increased roof strength. In addition to safety devices directly related to collisions, a variety of safety devices were introduced, including rotating headlights, anti-glare reflectors at night, and night vision with infrared cameras.

One of the things drivers shouldn't neglect at all times while driving is to check blind spots. Generally, mirrors are used to identify nearby vehicles, but when you change lanes or make turns, you cannot see them. To prevent accidents caused by failing to check blind spots, an auxiliary mirror is installed or the head is turned to check, but it is not absolutely safe because the eyes are far from the driving direction. Even the most skilled driver may be in danger of not knowing the vehicles in the blind spot when driving in poor visibility conditions such as night driving, fog, rain and snow. In particular, recently produced vehicles are excellent in soundproofing facilities, and thus, the vehicles that are close to each other cannot be detected at the level of noise that is felt indoors.

According to the traffic accident statistics of the Korea Road Traffic Safety Authority, about 5.7% of all car accidents are caused by overruns and lane changes. This is because the fatality rate was the highest (6.8 / 100 cases) after the frontal collision (10.7 / 100 cases) in all accidents, and the risk of left and right rear blind spots was not recognized. View mirrors have been used as one of the most basic parts of automobiles for over 70 years in terms of securing the vehicle's rear and rear view.

FIG. 1 is a diagram illustrating an area that can be grasped by a driver by an existing side mirror and a blind spot that occurs due to a side mirror or a visual limitation of the driver.

Referring to FIG. 1, the conventional side mirror has a blind spot A having a predetermined area due to limitations of the size and angle of the mirror. In general, the blind spot (A) is from the extension line of the mirror housing to the side lane to the side, from the housing extension line to the rear of 8m. A blind spot (A) is a place that cannot be seen through a side mirror or a rear mirror that is fixed to a vehicle. The blind spot (A) is generally a region adjacent to the front and rear of the vehicle and the weak side, and the larger the body, the wider the blind spot. As large vehicles increase, traffic accidents due to incomplete vision are on the rise. In order to solve this problem, the blind spot monitoring technology that can prevent accidents by securing the driver's view to the maximum possible has been developed in recent years.

For example, a mirror-based technology that combines an auxiliary mirror, such as a convex mirror, with a side mirror of a vehicle, and installs it in a required position. By using the display technology (CCTV), which reduces the blind spots in the rear view caused by a car change by adjusting the screen division of the monitor, and generating an alert sound when approaching a person or an obstacle using an ultrasonic and laser distance sensor. Technology to illuminate the light.

In addition, car makers are increasing interest in blind spot detection systems (BSD) to prevent the accidents caused by blind spots during lane changes. U.S., November 1993 Pat. No. 5418359 proposed a method to determine the presence of obstacles by a triangulation method using one emitter and two detectors, PD + (positive detector) and PD- (negative detector), and U.S. Pat. No.5112796 is a LED driver design circuit for driving the emitter of the blind spot sensor. U.S., July 1995 Pat. No.5675326, U.S. in May 1994. Pat. No.5463384 (Auto-Sense Ltd) is an infrared array configuration method for detecting blind spots consisting of multiple sensors, optical design method of each emitter and detector, and vehicle detection using them. One experimental method and results were described. U.S. in May 2003. Pat. No.0178892 (TRICO) has proposed a system that detects blind spot vehicles by installing multiple infrared sensors in the mirror housing and installs an alarm icon in front of the mirror in the side mirror.

2 is a configuration diagram of a blind spot detection system of a conventional vehicle, Figure 3 is a flow chart illustrating a blind spot detection process of the conventional blind spot detection system.

As shown in Figures 2 and 3, the conventional blind spot detection system includes a direction indicator detecting means (1) for detecting the operation of the direction indicator, and infrared sensor means (2) for detecting obstacles in the blind spot of the vehicle. And, an alarm means (3) provided to alert the driver whether the obstacle and the vehicle collide with each other, and determining whether the direction indicator light is in operation, and automatically detecting the obstacle when an obstacle is detected in the blind spot on the side where the direction indicator light is turned on. And control means 4 for driving (3).

In the conventional blind spot monitoring device having the above-described configuration, the infrared sensor means 2 in the target direction is activated (S102) by the lighting of the direction indicator (S101) to control the presence or absence of obstacles in the blind spot to the control means (4). In step S103, the object is recognized in step S104, and the result is provided to the driver by the alarm means 3, and the information is provided by the visual and audio alarm in step S105.

However, the operation mechanism as described above does not operate even in a situation where the side collision warning is to be performed because the alarm means 3 does not operate even if the driver changes lanes without the direction indicator.

Therefore, even if an obstacle is detected in a blind spot that the driver cannot check when changing lanes, there is no way to inform the driver of the accident, and the prevention function of the accident is reduced. .

Accordingly, an object of the present invention is to provide a collision avoidance system by detecting a blind spot of a vehicle that detects an obstacle in a blind spot and notifies the driver even when the driver does not operate a direction indicator when the lane is changed.

In addition, another technical problem to be achieved by the present invention is a collision avoidance system through the detection of blind spots of vehicles that provide information to the driver by removing the influence of external noise and detecting the road environment at a distance using a high efficiency infrared sensor. To provide.

According to the collision avoidance system through the blind spot detection of the vehicle according to an embodiment of the present invention in order to achieve the above object, the direction indicator detection means for detecting the presence or absence of lighting of the direction indicator of the vehicle; CCD camera means for taking a picture of the road environment and outputting it as road environment data to determine whether the current road environment is a curved road; Steering angle detection means for detecting a steering angle of the vehicle and outputting the steering angle signal; Infrared sensor means for transmitting and receiving infrared rays to and from an obstacle in a blind spot of the vehicle according to the steering angle signal of the steering angle detecting means and outputting a detection signal; Alarm means arranged to warn the driver of collision between the obstacle and the vehicle; And the infrared sensor means by determining that the direction indicator light is activated by the direction indicator light detecting means or changing a lane by receiving road environment data and a steering angle signal measured by the steering angle detection means by the CCD camera means. It is characterized in that it comprises a; control means for automatically driving the alarm means when the blind spot detection signal is applied from the blind spot.

In addition, the CCD camera means according to the invention, the light receiving unit for receiving an image of the obstacle; An image sensor operable to receive an image signal of an obstacle through the light receiver and generate an analog image signal of the obstacle; An A / D converter for converting an analog image signal of the image sensor into a digital image signal; And a central processing unit which receives the digital video signal of the A / D converter and transmits it to the control means.

In addition, the infrared sensor means according to the present invention, consisting of one or more infrared sensors, using a drive signal of each infrared sensor, a light emitting diode for outputting infrared rays for detecting the obstacle and the firing angle of the infrared rays output from the light emitting diode An IR sensor unit configured of a light receiving transistor positioned such that a reception angle of the receiver is fixed with respect to the beam; A transmission control unit controlling the IR sensor unit to output infrared rays using a pulse width modulation (PWM) controlled signal at a carrier frequency at a driving frequency of each sensor; And a reception control unit interlocked with the transmission control unit and controlling to read whether there is an obstacle by sensing each infrared ray. The IR sensor unit may further include a matching lens including a plurality of Plano ConveX Lenses that apply the principle of the composite lens to match the focal length of the light emitting diode.

In addition, the reception control unit according to the present invention includes a preamplifier for removing the driving frequency from the infrared rays flying from the transmission control unit in the allowed band pass filter; And a tone decoder configured to change the carrier frequency of the preamplifier into an electrical signal that can be determined by the control means.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. Like reference numerals denote like elements throughout the embodiments.

4 is a block diagram of a collision avoidance system by detecting a blind spot of a vehicle according to the present invention.

4, the collision avoidance system through the blind spot detection of the vehicle according to the present invention, the direction indicator light detection means 10, CCD camera means 20, steering angle detection means 30, infrared sensor means 40 , Alarm means 50 and control means 60.

First, the direction indicator light detecting means 10 according to the present invention will be described.

The direction indicator detecting means 10 detects whether the direction indicator of the vehicle is currently turned on, and detects the voltage applied to the direction indicator. In this state, when the direction indicator is turned on, the voltage drops due to the power consumption of the direction indicator. The difference between the rated voltage is obtained and the direction indicator detecting means 10 can detect the lighting state of the direction indicator satisfactorily.

Next, the CCD camera means 20 according to the present invention will be described.

The CCD camera means 20 is obtained by the image sensor 220, the image of the road environment entered through the light receiving unit 210, such as a lens. The image sensor 220 is an apparatus capable of electrically obtaining an image, such as a charge coupled device (CCD) or a charge injection device (CID). The output of the image sensor 220 is converted into digital data in real time through an A / D converter (Analog / Digital Converter) 230. The image information converted into digital data through the A / D converter 230 is temporarily stored in the memory 250 through the central processing unit 240. Image information stored in the memory 250 is transmitted to the control means 60 to be described later to output the image or to extract the information necessary for driving from the image. That is, the control means 60 extracts the slope of the road, the type of lane, the color, and the like from the road, and removes the influence of the changes in the roughness of the road and the noise. Afterwards, this information is categorized to complete detection of road environmental data that collectively depicts roads, obstacles, and obstacles.

Next, the steering angle detection means 30 according to the present invention will be described.

The steering angle detecting means 30 may be configured in various ways, of which the present invention will be described using a steering sensor and a gyro sensor generally known.

The steering sensor includes a slit disk installed on a steering shaft of a vehicle, a light interrupting diode (LED) and a phototransistor, and a photo interrupt installed on a steering column. The outer circumferential surface of the slit disk is disposed between the light emitting diode and the phototransistor. To be prepared. Therefore, when the steering shaft rotates, the photointerrupter can check the steering angle by generating an on / off pulse wave at a predetermined angle according to the transmission and blocking of light generated from the light emitting diode by the slit disk. . In addition, the gyro sensor is applied to the principle of Coriolis. For example, the gyro sensor is composed of a prism of an equilateral triangle, which is a vibrator. One side includes a piezoelectric ceramic element for feeding back a detected voltage, and the other two sides A piezoelectric ceramic element that is a detector is configured. When an AC voltage is applied to the vibrator, the motor vibrates at a constant frequency.In this state, when the car turns at a constant angular velocity, the piezoelectric ceramic detector of the sensor is inclined at right angles to the excitation direction by the Coriolis force and the AC voltage is output. . By synchronously detecting the excitation waveform of the AC waveform generated by the detector, it is possible to satisfactorily detect the turning direction and its magnitude. Such a gyro sensor can be easily installed anywhere in the vehicle, so it is easy to measure the steering angle by installing in a vehicle without a steering sensor.

Next, an infrared sensor means (IR-DETECTOR) 40 according to the present invention will be described.

5 is a view schematically showing a circuit of the infrared sensor means according to the present invention. As shown in FIG. 5, the infrared sensor unit 40 is equipped with an IR sensor unit 410, a transmission control unit 420 for transmitting infrared rays, and a reception control unit 430 for receiving reflected infrared rays, to the obstacle. The presence or absence of an obstacle can be determined according to the amount of reflected light reflected by the presence or absence.

The IR sensor unit 410 is a light emitting diode 412 for outputting infrared rays for sequentially detecting obstacles using the drive signal of each infrared sensor with respect to one or more infrared sensors, and is output from the light emitting diode 412 A light receiving transistor 414 is positioned so that the reception angle is at a constant angle with respect to the firing angle of the infrared rays. The structure of the sensor is, for example, the light emitting diode 412 and the light receiving transistor 414 are installed side by side facing each other, but the distance between the light emitting diode and the light receiving transistor is very much changed depending on the characteristics of the obstacle. It is desirable to give a slight angle. The distance between the obstacles can be changed depending on the angle and the distance between the two sensors.For example, when the angle is 5 ° and the distance is 9mm, there is a slight difference depending on the material of the reflector. Signals the driver for obstacles within 8 meters and 3.5 meters side. Sensing radius and other specifications can be adjusted to suit the local environment and legislation. The detection area of the IR sensor unit 410 detects vehicles in blind spots approaching the front side and the rear side which cannot be detected by the side mirror and the rearview mirror, and the IR sensor unit 410 is the front left and right sides of the vehicle. And preferably mounted in three rear positions. At this time, one or more infrared sensors of the IR sensor unit 410 means a sensor irrespective of the counting order.

In addition, the IR sensor unit 410 has a problem in that a large number of sensors must be mounted around the vehicle when the IR sensor unit 410 is mounted in a vehicle because the operating region is very narrow. Accordingly, in order to solve the problem that a large number of oscillators, drivers, amplifiers, and filters are required for the transmission / reception circuit of the IR sensor unit 410 and excessive cost is required, the IR sensor unit 410 according to the present invention is IR. The angle at which the infrared rays radiate from the sensor spread is called a half angle, which is composed of an optical system that collects the infrared rays emitted by the reflected angle. That is, the IR sensor unit 410 of the IR sensor unit 410 is provided with a matching lens 412a including a plurality of flat convex lenses (PCX; Plano ConveX Lens) applying the principle of the composite lens to match the focal length of the light emitting diode 412. The diameter of the infrared rays emitted from the light emitting diode 412 is set to 10 mm to enable recognition of obstacles to a long distance.

On the other hand, the transmission control unit 420 and the reception control unit 430 is driven by the control means 60 to be described later to exclude the influence from the external noise having a wavelength range similar to the LEDs used, such as the headlight or sunlight of the vehicle Carrying the carrier frequency on the frequency to drive the IR sensor unit 410 to prevent malfunction by sunlight or automotive headlights.

As shown in FIG. 5, the transmission control unit 420 drives the pulse width modulation signal of the LED using an AVR (Automatic Voltage Regulator) 422 so that the n infrared sensors output the respective channels. The frequency 57600 Hz and the carrier frequency are different from each other by 100 Hz to 1800 to 2600 Hz. The carrier frequency used here may propagate at a relatively long distance of 8m or more, excluding the influence of external noise affecting each reception control unit 430, i.e., mid-infrared rays present in the vehicle lighting and daytime sunlight. To play a role.

In addition, the reception control unit 430 is composed of a preamplifier (IR pre-amp) 432 and a tone decoder (434) to receive a minute signal to be determined by the control means (60).

When the emitted infrared rays hit an obstacle and are reflected by the reception controller 430, the signal is transmitted to the infrared preamplifier 432. The driving frequency (56700 Hz) used in the preamplifier 432 is removed, and only the respective carrier frequencies 1800, 1900 and 2000 kHz are output. The output carrier frequency is input to the control means 60 by the tone decoder 434 as a TTL level output, and the control means 60 determines the presence or absence of an obstacle and generates a visual and audio alarm by the alarm means 50. To the driver.

As such, the infrared sensor means 40 has a function of identifying an obstacle, such as a fire hydrant, existing on a distance from the vehicle, and may identify a vehicle approaching from an opposite side in a two-lane road.

Next, the alarm means 50 according to the present invention will be described.

The alarm means 50 is equipped with a warning light 510 or a speaker 520 to notify by the alarm sound according to the alarm signal, the mounting position of the warning light 510 is the vehicle inner surface of the left and right side mirrors and one side of the rearview mirror Approaching vehicle alerts, which can be mounted on one or more of these locations, in particular a small icon installed in the rear mirror, has the advantage that the driver can look at vehicles at a distance and in blind spots while keeping their eyes fixed on the mirror. In addition to visual alarms, the alarm may appear in the alarm sound or on the dashboard, depending on the vehicle manufacturer's preference.

Next, the control means 60 according to the present invention will be described. The control means 60 receives the signals of the above-mentioned direction indicator light detecting means 10, the CCD camera means 20, and the steering angle detecting means 30, and inputs them to the microprocessor 610.

The microprocessor 610 is determined to change lanes based on the information by turning on the indicator light or comparing the road environment data of the CCD camera means 20 with the steering angle signal of the steering angle detection means 30. Only the driving of the infrared sensor means 40 is started. The control means 60 determines the presence or absence of other vehicles or obstacles in the blind spot by the driven infrared sensor means 40, and transmits a detection signal to the alarm means 60 when there are vehicles or obstacles in the blind spot. You can print it out.

FIG. 6 is a flowchart illustrating a blind spot detection process of a collision avoidance system through blind spot detection of a vehicle according to an exemplary embodiment of the present invention.

In the present invention, in the state in which the infrared sensor means 40 is determined to change the lane through the direction indicator light (ON) (S201) or the comparison between the CCD camera operation (S202) and the steering angle signal detection (S203) (S204) It starts to work.

First, when the direction indicator is turned on (S201), the infrared sensor means 40 provided to have a transmission range in the blind spot of the vehicle transmits an infrared signal to the blind spot of the vehicle (S205) and receives an infrared signal reflected from an obstacle. It transmits the received signal to the control means 60. The control means 60 receiving the signal from above receives the signal sent from the infrared sensor means 40 and determines whether an obstacle is detected (S206). If it is determined that the obstacle is not detected, the control unit 60 transmits and receives an infrared signal again and repeats the above process. And, if it is determined that the obstacle is detected (S207) by turning on the warning light 510 of the alarm means 50 or by emitting a warning sound to the speaker 520 alerts the driver that there is an obstacle in the blind spot. (S208). Herein, when the obstacle is detected according to the driver's selection, the control means 60 operates the alarm means 50 to turn on the warning light 510 or the speaker 520 to output the warning sound, or both to operate in combination. You can also Such a selection may be provided by a driver by a separate selection switch (not shown). Alternatively, the driver may unconditionally display a warning signal and warn that an obstacle is detected by voice.

On the other hand, a case of changing lanes without turning on the turn indicators will be described.

If the lighting state of the direction indicator is not detected from the direction indicator detecting means 10, the CCD camera means 20 continuously monitors whether an obstacle is detected in the blind spot (S202). If the steering angle signal of the steering angle detection means 30 is detected (S203), if the steering angle signal is larger or smaller than the preprogrammed steering angle appearing when driving in a general curved road, it is determined that the lane is changed (S204) and the infrared rays of the infrared sensor means 40 are determined. Radiating (S205), and determines whether the obstacle is detected in the blind spot through the control unit 60 (S206). When the obstacle is detected in the blind spot (S207), the control means 60 transmits the possibility of collision with the obstacle through the warning means 50 to the driver through the warning light 510 or the speaker 520 (visually or acoustically). S208).

On the other hand, by checking the detected steering angle signal (S203), if it is almost equal to the preprogrammed steering angle appearing when driving in a general curved road, it is determined that the lane is not changed and the steering angle detecting means 30 continuously checks the steering angle (S204). This is for suppressing excessive warning by the alarm means 50 except for the steering angle detected for a short time or the magnitude of the angle is several degrees (°) or less, that is, the steering angle which appears during normal driving.

Thus, even if the driver does not operate the direction indicator at the time of lane change, the control means 60 compares the CCD camera means 20 and the steering angle detection means 30 to determine whether the lane is changed or not. ) Is an improved useful invention of the actuation mechanism so that it can be operated.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments thereof are possible. The true technical protection scope of the invention should be defined only by the appended claims.

 The present invention by the configuration as described above enables the operation of the blind spot detection device even when the direction indicator is not in operation to alert the driver to the presence or absence of the vehicle in the blind spot of the vehicle, to prevent accidents that may occur during the lane change process Many beginners and female drivers can play a major role in eliminating the difficulty of changing lanes.

In addition, according to the present invention has the effect of preventing the influence of external noise of the blind spot detection sensor.

Claims (5)

Direction indicator light detecting means (10) for detecting the presence or absence of lighting of the direction indicator of the vehicle; CCD camera means 20 for taking a picture of the road environment and outputting it as road environment data to determine whether the current road environment is a curved road; Steering angle detection means (30) for detecting a steering angle of the vehicle and outputting the steering angle signal; Infrared sensor means (40) for transmitting and receiving infrared rays to and from an obstacle in a blind spot of the vehicle according to the steering angle signal of the steering angle detection means (30) and outputting a detection signal; Alarm means (50) provided to alert the driver whether the collision between the obstacle and the vehicle; And It is determined that the direction indicator is activated by the direction indicator detection means 10 or the state of changing lanes by receiving road environment data and steering angle signals measured by the steering angle detection means by the CCD camera means 20. The blind spot detection of the vehicle, characterized in that it comprises a; control means 60 for automatically driving the alarm means 50 when the obstacle detection signal of the blind spot is applied from the infrared sensor means 40 Collision Avoidance System. The method of claim 1, wherein the CCD camera means 20, A light receiving unit 210 for receiving an image of an obstacle; An image sensor 220 which receives an image signal of an obstacle through the light receiving unit 210 and generates an analog image signal of the obstacle; An A / D converter 230 for converting an analog image signal of the image sensor 220 into a digital image signal; And Central processing unit 240 for receiving the digital image signal of the A / D converter 230 and transmits it to the control means 60; collision avoidance system by detecting the blind spot of the vehicle, characterized in that it comprises a . The method of claim 1, wherein the infrared sensor means 40, Comprising one or more sensors, using a drive signal of each sensor, the light emitting diode 412 for outputting infrared rays for detecting the obstacle and the angle of reception with respect to the firing angle of the infrared rays output from the light emitting diode 412 An IR sensor unit 410 composed of a light receiving transistor 414 positioned to have; A transmission control unit 420 for controlling the IR sensor unit 410 to output infrared rays by using a pulse width modulation (PWM) controlled signal at a carrier frequency at a driving frequency of each sensor; And And a reception control unit 430 interlocked with the transmission control unit 420 so as to detect each infrared ray to read whether there is an obstacle, and avoiding blind spots of the vehicle. The method of claim 3, wherein the IR sensor unit 410, Matching lens 412a consisting of a plurality of Plano ConveX Lens applying the principle of the compound lens to match the focal length of the light emitting diode 412; blind spot of the vehicle further characterized Collision avoidance system through detection. The method of claim 3 or 4, wherein the reception control unit 430, A preamplifier 432 for removing the driving frequency from the infrared rays emitted from the transmission control section 420 in the allowed band pass filter; And And a tone decoder 434 for changing the carrier frequency of the preamplifier 432 into an electric signal that can be determined by the control means 60. The collision avoidance system by detecting blind spots of the vehicle further comprises a tone decoder 434. .

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