KR20110002288A - Lane departure warning apparatus using laser - Google Patents

Abstract

PURPOSE: A lane derailing warning apparatus using laser is provided to accurately detect the lane by irradiating the laser on the road with different radiation angle using a reflection mirror. CONSTITUTION: A lane derailing warning apparatus using laser comprises a laser irradiation unit(110), a reflective mirror part(120), a laser receiver, and a lane determining unit. The laser irradiation unit irradiates the laser. The reflective mirror part changes the radiation angel of the laser irradiated to the road by reflecting the laser with different angle.

Description

Lane departure warning apparatus using laser

The present invention relates to an apparatus for recognizing a lane of a road surface using a laser. More specifically, the present invention relates to a laser signal that is irradiated to a road surface at different irradiation angles through a reflecting mirror and is reflected back from the road surface. The lane departure warning device for determining the content of the identifier of the road surface, such as the distance between the lane and the vehicle or the lane based on the change in the intensity of the.

In recent years, studies are being actively conducted to prevent accidents by warning the driver by predicting potential accidents while driving away from post-safety measures such as seat belts or airbags that minimize the driver's damage from various accidents occurring while driving the vehicle. Is going on.

In general, ASV (Advanced Safety Vehicle) is an advanced vehicle that applies advanced electronic and control technology to improve the safety of the vehicle. It reduces traffic accidents, increases traffic volume, saves energy, and facilitates driver's convenience. The Lane Departure Warning System (LDWS) is an ASV that detects lanes that are currently running, and alerts you if a driver attempts to leave the lane due to inattention or drowsy driving. Device.

1 schematically depicts a typical reciprocating four lane road.

Referring to FIG. 1, the lanes are largely marked in white and yellow. The two yellow solid lines in the middle of the road surface represent the center line, and the left two lanes are the up line and the right two lanes are the down line among the four round-trip roads based on the center line. The two lanes of the up line and the down line are marked with a white dashed driving line, and the vehicles of the up line or the down line can travel by changing the driving line with each other. On the other hand, the road surface is a crosswalk that pedestrians can cross the lane, and the crossing line representing the crossing is indicated by a solid white line. The lanes marked on the road are composed of the center line, the traveling line, the crossing, and the width of the lanes differs depending on the type of lane.

The lane departure warning system, which is applied or developed to a vehicle traveling on a road surface in which various types of lanes are shown, is mainly using optical instruments such as a CCD camera. This system is focused on the fact that the shape and color of the center line and the driving line is different from the shape and color of the road surface.The system analyzes the image data captured by the CCD camera to determine the centrality or lane, and then invades the center line or stops the lane. In case of departure, the driver will be alerted. Furthermore, intelligently developed vehicles have also been proposed to identify lanes and to drive themselves while maintaining lanes.

The configuration of the conventional LDWS (hereinafter referred to as 'prior art 1') is, as shown in Figure 1, the image sensor unit for receiving the forward and backward driving image, the image processing unit for performing image processing for lane recognition, and the recognized lane It is composed of a departure determination unit for determining whether the vehicle is separated based on the, an interface input unit for receiving a vehicle interface (Interface) signal, and an interface output unit for indicating the lane departure warning and the situation. At this time, the vehicle interface is composed of various variables such as lane width, lane curvature radius, lane crossing time. Here, the image sensor unit recognizes the lane on the road by using a plurality of cameras installed in the front and rear center, and detects the difference between the detected lane center and the camera optical axis to generate a lane departure warning.

On the other hand, the lane departure warning system disclosed in Korean Patent Laid-Open No. 10-2008-0088675 (hereinafter referred to as 'Prior Art 2') uses a lane from a left and right image input by a plurality of cameras installed in both side mirrors. 3D mapping of the extracted left and right lanes to obtain the actual coordinates of the lanes, and calculating the left and right direction angles at the intersection points of the straight lines and the direction lines of the vehicle bodies. The left and right side distances are calculated from a straight line consisting of real coordinates, the lane departure distance is calculated by the geometric analysis of the direction angle and the side distance, and the departure time is calculated from the vehicle speed detected by the vehicle speed sensor and the departure time from the lane departure distance. When the reference value is less than this threshold, an alarm is generated to prevent a vehicle accident due to lane departure.

On the other hand, the lane departure warning system (hereinafter referred to as 'prior art 3') disclosed in Korean Utility Model No. 20-2000-0015809 does not use a CCD camera and judges the centerline invasion by a relatively simple and inexpensive configuration. An apparatus for generating an alarm, comprising: a laser beam transmitter mounted on a vehicle (preferably to the left of the vehicle front) and firing a laser beam at a predetermined angle toward the lower side of the vehicle; A laser beam receiver mounted on the right side of the beam transmitter and receiving a laser beam that is returned after the emitted laser beam is reflected on the road, a laser driver for driving the laser beam transmitter and the laser beam receiver, a center line, a lane and a road surface. Look-up table that stores the intensity data of the received laser beam according to the state, alarm and laser to alert the centerline of the vehicle The central control unit receives the intensity data of the received laser beam from the driver and inquires the intensity data of the received laser beam received from the look-up table to determine whether the current vehicle has invaded the center line and to generate an alarm when the center line is invaded. It is configured to include.

The above-described prior art 1 and the prior art 2 use the CCD camera disposed in the vehicle to photograph the road around the vehicle and process the image of the photographed road to recognize the lane, and use various variables calculated from the recognized lane. To determine whether the vehicle has left the lane. Therefore, expensive equipment for processing complex processes such as CCD camera, image processing unit, lane recognition unit, and lane departure determination unit using various variables is required.It is difficult to quickly calculate lane departure in real time in a fast moving vehicle. Has the problem.

On the other hand, the prior art 3 by detecting the lane by measuring the intensity of the laser signal reflected back from the road surface, it is possible to determine whether the lane departure of the vehicle with a relatively simple configuration and low cost. However, due to the presence of sunlight, the headlights of surrounding vehicles, or ambient lighting around the moving vehicle, the intensity of the background light received by the surrounding environment of the vehicle is different from each other, and thus the laser according to the lane stored in the lookup table is simply different. It is difficult to accurately determine the lane using only the strength of the signal. In addition, one of the most important factors in the lane departure warning system is the distance between the lane and the vehicle or the speed of change of the distance between the lane and the vehicle, and the prior art 3 configuration cannot measure the distance between the lane and the vehicle. I have a problem. Moreover, the prior art 3 distinguishes the type of lane using only the intensity of the reflected laser, but has a problem in that it is difficult to accurately classify the type of lane using only the laser intensity.

Accordingly, an object of the present invention is to provide a lane departure warning device that can be manufactured with a relatively simple configuration and low cost.

Another object of the present invention is to provide a lane departure warning device capable of not only detecting a lane but also measuring the type of the lane or the distance between the lane and the vehicle.

Another object of the present invention is to accurately detect the lane by irradiating the laser to the road surface at different irradiation angles through the reflection mirror, lane departure that can measure the type of lane or the distance between the lane and the vehicle To provide a warning device.

The lane departure warning apparatus according to the present invention includes a laser irradiation unit for irradiating a laser modulated at a high frequency and a reflection mirror unit for changing an irradiation angle of a laser irradiated to a road surface by reflecting the laser irradiated from the laser irradiation unit at different reflection angles. And a laser receiver for filtering and receiving only a high frequency laser signal from a signal reflected from the road surface and searching for a lane displayed on the road surface based on a change in intensity of the received laser signal, and a distance between the lane and the vehicle or It includes a lane determination unit for determining the type of the searched lane.

The reflecting mirror section includes a reflecting mirror which reflects the irradiated laser to the road surface and a driving unit which drives the reflecting mirror to change the irradiation angle of the laser irradiated to the road surface through the reflecting mirror.

Preferably, the reflecting mirror is a shape of a polygonal pillar having a plurality of reflecting surfaces laterally reflecting the irradiated laser to the road surface, and the driving unit is the irradiation of the laser is reflected on the reflecting surface and irradiated to the road surface by rotating the reflecting mirror It is characterized by changing the angle. More preferably, the reflecting mirror is characterized in that a plurality of reflecting surfaces are in the shape of regular polygonal pillars which are the same.

A lane determination unit that detects a lane, determines a distance between the lane and the vehicle, or determines a type of the detected lane detects a change in the intensity of the received laser and searches for a lane on the road surface based on the detected change in the intensity of the laser. A lane search unit for calculating the distance between the vehicle and the road surface laser irradiation point at the time when the intensity change of the receiving laser starts and the time when the intensity change of the receiving laser ends, respectively, and the calculated vehicle and road A lane width calculation unit for calculating the width of the searched lane based on the distance between the plane laser irradiation points and a lane type determination unit for determining the type of lane based on the calculated lane width.

Lane departure warning device according to the present invention has a variety of effects as follows compared to the conventional lane departure warning device.

First, the lane departure warning apparatus according to the present invention can accurately detect a lane by irradiating a laser onto a road surface at different irradiation angles using a reflection mirror.

Second, the lane departure warning apparatus according to the present invention uses a low-cost laser and recognizes the lane based on the change in the intensity of the laser beam reflected from the road surface, so that the lane departure warning can be easily confirmed at low cost.

Third, the lane departure warning apparatus according to the present invention can determine the type of the lane by measuring the width of the lane by irradiating the laser beam to a predetermined width of the road surface repeatedly by a predetermined period and detecting the increase or decrease of the intensity of the received laser beam. have.

Hereinafter, a lane departure warning apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

2 illustrates an example in which the lane departure warning apparatus according to the present invention is mounted on a vehicle.

Referring to FIG. 2, the lane departure warning device according to the present invention is installed at a position where the vehicle 10 can irradiate a laser to the road 40 of the currently running lane. Preferably, the lane departure warning device according to the present invention is installed on the left or right side of the vehicle so as to irradiate the laser to the lane 30 displayed on the road surface in the driving direction of the vehicle when the road driving, more preferably the vehicle Is installed on the left or right front of the. Lane departure warning system according to the present invention sikimyeo change the reflection angle of the laser (θ _r) in order, according to the changed reflection angle (θ _r) of the laser at different irradiation angles (θ _i) is irradiated with the road surface. As the irradiation angle θ _i is changed, the laser is irradiated at different distances d from the vehicle, and the laser which is irradiated on the road surface at different irradiation angles θ _i is reflected off the road surface and again leaves the lane. Received by the alerting device 20.

When the vehicle departure warning apparatus according to the present invention is largely divided into functional units, the unit 100 for irradiating a laser onto the road surface and the unit 200 for receiving a laser beam reflected from the road surface and determining whether the lane is separated have. FIG. 3 is a functional block diagram for explaining the laser irradiation unit 100 in more detail, and FIG. 4 is a functional block diagram for explaining the unit 200 that determines whether a lane is separated by receiving a laser.

First, the laser irradiation unit 100 will be described in more detail with reference to FIG. 3. The laser irradiation unit 100 reflects the laser irradiation unit 110 and the laser irradiated from the laser irradiation unit 110 at different reflection angles. It includes a reflecting mirror 120 for reflecting to and changing the irradiation angle of the laser irradiated to the road surface.

The laser irradiator 110 includes a modulation controller 111 for modulating the irradiated laser at high frequency and a laser generator 113 for generating and irradiating a laser of a predetermined high frequency under the control of the modulation controller 111. On the road surface on which the vehicle travels, there are various noise lights generated from sunlight, headlights of other vehicles driving around, lane changing lights, and the like. Solar light, headlights of other vehicles traveling around, lane changing lights, or lights located on roads are generally composed of direct current or low frequency components. Accordingly, the modulation controller 111 controls the laser generator 113 to generate a laser of a specific frequency in order to generate a laser signal that can be distinguished from various noise light existing on the road surface. Preferably, the modulation control unit 111 modulates the laser at a high frequency of several MHz or more in order to distinguish between the light existing around the vehicle and the laser irradiated by the laser irradiation unit 110.

The reflecting mirror unit 120 may reflect the laser irradiated from the laser irradiation unit 110 to the road surface, and the reflecting mirror 121 to change the reflection angle of the laser reflected through the reflecting mirror 121. And a driving unit 123 for driving the engine. The reflecting mirror 121 has one reflecting surface or a plurality of reflecting surfaces for reflecting the laser irradiated from the laser irradiator 110 onto the road surface. In one example of the reflective mirror 120, the driving unit 123 reciprocates the reflective mirror 121 at a predetermined rotation angle, and changes the reflection angle of the laser reflected from the reflective surface through the reciprocating rotation to the road surface. The irradiation angle of the irradiated laser is changed. In another example of the reflective mirror 120, the driving unit 123 rotates the reflective mirror 121 at a predetermined rotational speed, and changes the reflection angle of the laser reflected from the reflective surface through the rotational movement to be irradiated onto the road surface. Change the irradiation angle of the laser. By changing the irradiation angle of the laser irradiated to the road surface through the rotational movement of the reflective mirror 121, the laser sequentially irradiates a predetermined width of the road surface. As the angle of irradiation varies, the laser is irradiated at different separation distances from the vehicle, hereinafter the largest separation distance is referred to as the irradiation width. In addition, the number of irradiation times of the laser to the irradiation width for a unit time is referred to as the number of irradiation.

Referring to Figure 4 in more detail with respect to the unit 200 for determining the lane departure, the unit 200 for determining whether the lane departure is laser receiver 210 for receiving a laser signal reflected back from the road surface And a lane determination unit 220 for detecting a lane by detecting a change in the intensity of the received laser signal, determining a distance between the lane and the vehicle, or determining a type of the detected lane, and information on the lane type according to the lane width. A lane information storage unit 230 for storing the information; and a warning controller 240 to warn the user of lane departure or warn the centerline invasion based on the determined distance between the determined lane and the vehicle or the type of the detected lane. .

5 and 6, the laser receiver 210 is mixed with the laser receiver 211 and the received laser signal to receive the laser signal reflected from the road surface. AC coupling unit 213 for removing a DC component signal, filtering unit 215 for filtering only a specific frequency band from an AC coupled laser signal or removing a noise signal, and converting a laser signal of a filtered analog into a digital value An analog-to-digital converter 217 is provided. The laser irradiated to the road surface through the laser irradiator is a high frequency component, where the AC coupling unit 213 and the filtering unit 215 are a direct current (DC) component or a low frequency in the laser signal received to filter only a high frequency laser signal. The noise signal in the band is operated as a high frequency filter.

The first graph shown in FIG. 6 (a) shows the intensity of the received laser signal without the DC component mixed, and the second graph shown in FIG. 6 (a) shows the received laser signal with the sunlight mixed. FIG. 6 (a) shows the intensity of the received laser signal in which headlights of surrounding vehicles are mixed. The headlights of sunlight or surrounding vehicles act as DC components of constant size. Meanwhile, the first to third graphs shown in FIG. 6 (b) show the intensity of a laser signal AC-coupled by removing the DC component from the first to third graphs shown in FIG. 6 (a). Doing.

Referring to FIG. 4, the lane determination unit 220 detects the intensity change of the received laser and detects the intensity change of the received laser based on the detected intensity change of the road surface. A lane search unit 221 for searching for a lane of a distance, and a distance calculator 223 for calculating a distance between the vehicle and the lane at the time when the intensity change of the reception laser starts and the time when the intensity change of the reception laser ends. And calculating the width of the searched lane based on the distance difference between the vehicle and the lane calculated at the beginning of the change in intensity of the received laser and the distance between the vehicle and the lane calculated at the end of the change in the intensity of the received laser. A lane width calculation unit 225 and a lane type determination unit 227 for determining the type of lane based on the calculated lane width are provided.

The road surface is paved with asphalt, cement, etc., and various kinds of white or yellow lanes are marked on the paved road surface. When the laser is irradiated to the road surface, the laser is reflected at a stronger intensity on the road surface where the lane is displayed than on the road surface where the lane is not displayed. The lane searching unit 221 searches for lanes on the road surface by changing the relative intensity of the received laser.

The lane type determination unit 227 recognizes the lane type using information on the calculated lane width and the lane width stored in the lane information storage unit 230. Preferably, the lane information storage unit 230 divides the lane width into a predetermined unit interval according to the lane type, and the lane type determination unit 227 may determine a predetermined unit interval if the calculated lane width belongs to the predetermined unit interval. Recognize it as a mapped lane. For example, the width of the white driving lane is divided into 10 to 15 cm and the width of the yellow central lane to 15 to 20 cm in the lane information storage unit 230, and the lane type determination unit 227 calculates the width of the lane to 11 cm. In the case of, the detected lane is recognized as a white driving lane.

The warning control unit 240 outputs a warning signal to the user based on the distance between the vehicle and the lane determined by the lane searching unit 221, the distance calculating unit 223, and the lane type determining unit 227. Outputs a warning signal to the user based on this.

Looking at an example of the reflective mirror with reference to Figure 7 (a), the reflective mirror 121 is the shape of an octagonal pillar having a plurality of reflecting surfaces 151 reflecting the laser irradiated from the laser irradiation unit to the road surface. . Reflection angle θ _r of the laser reflected from the reflecting surface 151 as the reflecting mirror 121 rotates clockwise about a driving shaft 153 extending from the center of the reflecting mirror 121 having an octagonal pillar shape ) Changes. The irradiation width of the road surface is irradiated once through one reflective surface 151, and the reflective mirror of the octagonal pillar composed of eight reflective surfaces irradiates eight times the irradiation width of the road surface as one rotation. FIG. 8 shows the reflection angle of the laser that is reflected to the reflecting surface when the reflecting mirror shown in FIG. 7 (a) is rotated.

In FIGS. 7A and 8, an octagonal reflective mirror is described as an example, but as the number increases, the number of inquiries per unit time increases at the same rotational speed. Therefore, the present invention controls the rotational speed of the reflection mirror or adjusts the shape of the rotation mirror according to whether it is necessary to determine whether the vehicle departs more precisely and quickly or according to the processing capability of the unit 200 that determines whether the vehicle departs. It can select and manufacture according to the required objective of this invention. Preferably, the reflecting mirror is characterized in that the plurality of reflecting surfaces are regular polygonal columns equal to each other.

Referring to another example of the reflective mirror with reference to FIG. 7B, the reflective mirror 121 has a rectangular plate shape having, as one surface, a reflective surface 161 for reflecting the laser beam irradiated from the laser irradiator on the road surface. Reflection mirror 121 is driven to a reciprocating rotary movement in a predetermined angle (θ _t), the reflection mirror 121, the reflection of the laser reflected by the reflecting surface 161 as a reciprocating rotational motion in a predetermined angle (θ _t) The angle θ _r changes. When the reflective mirror 121 performs one reciprocating rotational motion at the set angle θ _t , the irradiation width of the road surface is irradiated twice. FIG. 9 shows the reflection angle of the laser reflected to the reflecting surface during the reciprocating rotation drive at the set angle of the reflecting mirror shown in FIG. 7 (b).

10 illustrates an example of an irradiation laser signal and a reception laser signal. Referring to FIG. 10, a method of calculating a distance between a vehicle and a lane in a distance calculator and a method of calculating a lane width in a lane width calculator are described with reference to FIG. 10. Take a look.

FIG. 10A illustrates an example of a laser signal irradiated onto a road surface through a reflection mirror. As shown in Fig. 10A, the laser signal irradiated onto the road surface is pulse width modulated at a high frequency. On the other hand, Figure 10 (b) shows an example of the laser signal received by reflected from the road surface after being irradiated to the road surface.

Although the laser signal reflected from the actual road surface is mixed with a noise signal of DC or low frequency components, the noise signal of DC and low frequency components is removed by AC coupling and filtering to obtain a laser signal as shown in FIG. 10 (b). Create As shown in FIG. 10 (b), the laser signal received from the first point in time t2 is a laser signal reflected at the position where the lane of the road surface starts, and thus, the laser signal received before the first point in time t2. It is relatively large compared to its strength. Since the intensity of the laser signal received from the second time point t4 is a laser signal reflected at a position where the lane of the road surface ends, the intensity of the laser signal received before the first time point t2 is returned. That is, the first time point t2 is a start point of the change in intensity of the received laser, and the second time point t4 is a time point at which the change in intensity of the received laser is finished. The distance calculator calculates the distance between the vehicle and the lane, that is, the distance between the vehicle and the laser beam, at the first and second time points, respectively, based on the difference between the irradiation time of the laser and the reception time of the laser.

Meanwhile, the lane width calculation unit is configured based on a difference between the distance between the lane and the vehicle calculated at the start of the received laser intensity change and the distance between the lane and the vehicle calculated at the end of the received laser intensity change. Calculate lane width That is, the difference between the distance calculated between the lane and the vehicle calculated when the intensity change of the received laser starts and the distance calculated between the lane and the vehicle calculated when the intensity change of the received laser signal ends is the width of the detected lane.

FIG. 11 is a flowchart illustrating an example of outputting a warning signal to a driver based on a distance between a vehicle and a lane or a type of a lane determined by the warning controller. Referring to FIG. 11, the lane is searched for in detail. The distance between the lane and the vehicle is calculated (S1), and the type of the searched lane is determined (S3). It is determined whether the type of the searched lane is the center lane (S5). When it is determined as the center lane, it is determined whether the distance between the center lane and the vehicle is equal to or less than the first threshold value TH1 (S7). When the distance between the center lane and the vehicle is less than or equal to the first threshold value, the controller 100 outputs a warning signal to the user (S9). The warning signal is output as a warning sound to the driver through the speaker installed in the vehicle or as a warning message to the driver through the display installed in the vehicle.

FIG. 12 is a flowchart illustrating another example of outputting a warning signal to a driver based on a distance between a vehicle and a lane or a determined lane by the warning controller. Referring to FIG. 12, the lane is searched for in detail. The distance between the lane and the vehicle is periodically calculated (S11), and the distance change speed between the vehicle and the lane is calculated based on the calculated distance between the lane and the vehicle (S13). If it is determined whether the calculated distance change speed between the lane and the vehicle is greater than or equal to the second threshold value TH2 (S15), and the determined distance change speed between the calculated lane and the vehicle is determined to be greater than or equal to the second threshold value TH2. Control to output a warning signal to the user (S17). The warning signal is output as a warning sound to the driver through the speaker installed in the vehicle or as a warning message to the driver through the display installed in the vehicle.

What has been described above is merely an exemplary embodiment of the lane departure warning apparatus according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, it departs from the gist of the present invention. Without this, anyone skilled in the art to which the present invention pertains will have the technical spirit of the present invention to the extent that various modifications can be made.

1 schematically depicts a typical reciprocating four lane road.

2 illustrates an example in which the lane departure warning apparatus according to the present invention is mounted on a vehicle.

3 is a functional block diagram for explaining the unit 100 for irradiating a laser in more detail.

4 is a functional block diagram for explaining in more detail the unit 200 for receiving a laser to determine whether the lane departure.

5 is a functional block diagram illustrating the laser receiver in more detail.

6 illustrates a laser signal received through a laser receiver.

7 shows an example of a reflecting mirror according to the present invention.

8 and 9 show examples of driving according to the reflecting mirror.

10 shows an example of an irradiation laser signal and a reception laser signal.

FIG. 11 is a flowchart illustrating an example of outputting a warning signal to a driver based on a distance between a vehicle and a lane or a type of a determined lane by the warning controller.

12 is a flowchart illustrating another example of outputting a warning signal to a driver based on the distance between the vehicle and the lane or the type of the determined lane by the warning controller.

Description of the main parts of the drawing

10: vehicle 20: lane departure warning device

30: road surface 40: lane

110: laser irradiation unit 120: reflective mirror unit

151: reflective surface 153: drive shaft

161: reflective surface 163: drive shaft

210: laser receiver 220: lane determination unit

221: lane search unit 223: distance calculation unit

225: lane width calculation unit 227: lane type determination unit

230: lane information storage unit 240: warning control unit

Claims (10)

A laser irradiation unit for irradiating a laser; A reflection mirror unit for changing the irradiation angle of the laser irradiated onto the road surface by reflecting the laser irradiated from the laser irradiation unit at different reflection angles; A laser receiver for receiving a laser beam reflected from the road surface; And And a lane determination unit configured to search for a lane displayed on the road surface based on the received intensity change of the laser, and determine a distance between the lane and the vehicle or the type of the searched lane. The method of claim 1, wherein the reflective mirror portion A reflection mirror reflecting the irradiated laser to a road surface; And And a driving unit for driving the reflective mirror to change the irradiation angle of the laser emitted to the road surface through the reflective mirror. The method of claim 2, The reflecting mirror is in the shape of a polygonal pillar having a plurality of reflecting surfaces laterally reflecting the irradiated laser to the road surface, And the driving unit rotates the reflective mirror based on one axis of the reflective mirror to change the irradiation angle of the laser reflected to the reflective surface and irradiated onto the road surface. The method of claim 3, wherein The reflective mirror is a lane departure warning device, characterized in that the plurality of reflecting surfaces of the same polygonal polygonal shape. The method of claim 4, wherein the lane determination unit A lane searching unit for detecting a change in intensity of the received laser and searching for a lane of a road surface based on the detected change in intensity of the laser; A distance calculator configured to calculate a distance between the vehicle and the lane at the time when the change in the intensity of the receiving laser starts and when the change in the intensity of the receiving laser ends; The width of the searched lane is calculated based on the distance between the vehicle and the lane calculated at the start of the intensity change of the receiving laser and the distance difference between the vehicle and the lane calculated at the end of the intensity change of the receiving laser. A lane width calculation unit for calculating; And And a lane type determination unit configured to determine the type of the lane based on the calculated lane width. The method of claim 5, wherein the lane departure warning device Further comprising a lane information storage unit for storing information on the lane width according to the lane type, And the lane type determining unit determines the type of the searched lane using the calculated lane width and the lane width information stored in the lane information storage unit. The method of claim 5, wherein the lane determination unit And a warning controller configured to generate a warning sound to the user based on the calculated distance between the vehicle and the lane, or generate a warning sound to the user based on the type of the determined lane. The method of claim 7, wherein the warning control unit And a warning signal is output to the user when the distance between the vehicle and the lane is less than or equal to a first threshold based on the determined type of the lane and the determined distance between the vehicle and the lane. The method of claim 7, wherein the warning control unit A lane departure warning device outputting a warning signal to a user when a distance change speed between the vehicle and the lane exceeds a second threshold based on the determined type of the lane and the determined distance between the vehicle and the lane; . The method of claim 5, wherein the laser irradiation unit A modulation control unit for high frequency modulation of the laser signal irradiated onto the road surface so as to be distinguished from the ambient light; And And a laser generator for generating a laser signal modulated according to the control of the modulator.

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