JP3903752B2 - Object detection apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an object detection apparatus and method, and more particularly, to an object detection apparatus and method that can detect an optical axis shift.
[0002]
[Prior art]
Conventionally, using the laser radar installed in the car, measure the distance between the car and the car that runs in front, and if this distance is less than the safe distance, the driver will be warned to take more distance, There is an object detection device that automatically controls the speed of the own vehicle to increase the distance from the preceding vehicle. The outline of this apparatus will be described with reference to FIG.
[0003]
In FIG. 1, the own vehicle 1 in which the object detection device 2 is installed in front of the vehicle is traveling from left to right in the figure. A preceding vehicle 5 is traveling in the same direction as the own vehicle 1 in front of the own vehicle 1. The laser radar 3 of the object detection device 2 emits (projects) the laser light 4 toward the front of the host vehicle. The laser light 4 is reflected at the rear part of the preceding vehicle 5, and the reflected light is received by the laser radar 3. The object detection device 2 measures the time from when the laser beam 4 is projected by the laser radar 3 until it is reflected by the preceding vehicle 5 and received by the laser radar 3, and from that time, the subject vehicle 1 And the inter-vehicle distance of the preceding vehicle 5 is calculated.
[0004]
Then, the object detection device 2 determines that the distance between the vehicle 1 and the preceding vehicle 5 calculated in this way is a preset safe distance (when the preceding vehicle 5 causes an accident or suddenly stops, If it is determined that the vehicle 1 is less than the distance at which the vehicle 1 can avoid danger), the driver of the vehicle 1 is warned to increase the distance between the vehicles, and the speed of the vehicle 1 is automatically controlled. To ensure a safe inter-vehicle distance.
[0005]
[Problems to be solved by the invention]
However, such an object detection device 2 has a problem that the distance from the preceding vehicle 5 cannot be accurately measured as shown in FIG. 2 when the optical axis of the laser light 4 projected by the laser radar 3 is shifted. It was.
[0006]
In FIG. 2, the laser light 4 projected by the laser radar 3 is shown in FIG. 1 due to, for example, distortion due to a light collision of the own vehicle 1 or loosening due to secular change of the fixing mechanism that fixes the laser radar 3. Compared with the normal light projecting direction of the laser light 4, the light projecting angle is inclined upward.
[0007]
In such a case, the laser radar 3 cannot receive the reflected light of the laser beam 4 until the preceding vehicle 5 approaches the position of the preceding vehicle 5 indicated by a broken line. For this reason, when the inter-vehicle distance between the subject vehicle 1 and the preceding vehicle 5 is longer than the position of the preceding vehicle 5 indicated by the broken line, the object detection device 2 cannot detect the presence of the preceding vehicle 5 as well as the inter-vehicle distance.
[0008]
Therefore, there is a problem that the preceding vehicle 5 cannot be detected until the vehicle approaches an abnormality, and the emergency situation cannot be dealt with.
[0009]
In order to solve this problem, for example, Japanese Patent Application Laid-Open No. 11-194169 discloses a vehicle object detection device including an inclination detection unit that detects an inclination of the device itself with respect to a road surface.
[0010]
The vehicle object detection device disclosed in this publication is different from the first laser radar that projects laser light in a direction parallel to the road surface in order to measure the inter-vehicle distance from the preceding vehicle. In order to measure the inclination with respect to the road surface, second and third laser radars that project laser light at a predetermined angle toward the road surface are provided.
[0011]
In this vehicle object detection device, the angle of the vehicle object detection device itself with respect to the road surface is calculated based on the measurement results of the distance from the road surface by the second and third laser radars. The angle of the optical axis of the laser light projected from the radar is calculated.
[0012]
However, in the invention of the above publication, it is necessary to install the second and third laser radars for measuring the inclination of the vehicle object detection device separately from the first laser radar for measuring the inter-vehicle distance. As a result, there is a problem that the apparatus becomes large and expensive.
[0013]
The present invention has been made in view of such a situation, and makes it possible to detect the deviation of the optical axis of the laser light 4 with a simple configuration.
[0014]
[Means for Solving the Problems]
The first object detection apparatus of the present invention includes an emitting means for emitting a beam, a receiving means for receiving a reflected beam reflected by an object emitted by the emitting means, and a reflected beam received by the receiving means. Measurement means for measuring the distance to the object reflecting the beam, recognition means for recognizing an overhead sign on the road surface based on the reflected beam received by the reception means, and recognition of the overhead sign by the recognition means The deviation of the emission direction of the beam emitted by the emitting means is detected based on the specifying means for specifying the distance to the overhead sign and the distance to the overhead sign specified by the specifying means immediately before the point becomes impossible. And a detecting means.
[0015]
The emitting unit and the receiving unit are, for example, the laser radar 3 of FIG. 3, which emits a beam and receives a reflected beam reflected by a road surface and an object on the road surface. The measurement means is, for example, the object recognition / distance measurement unit 13 in FIG. 3, and calculates the distance to the object based on the reflected beam received by the reception means. The recognition means is, for example, the object recognition / distance measurement unit 13 in FIG. 3, and recognizes an overhead sign on the road surface based on the reflected beam received by the reception means.
[0016]
The specifying means is, for example, the object recognition / distance measuring unit 13 in FIG. 3, and between the start of recognition of the overhead sign by the recognition means and the disappearance of the recognition of the overhead sign between the object detection device and the overhead sign. When the overhead marker is no longer recognized by the recognition means, the distance to the overhead marker measured immediately before is determined.
[0017]
The detection means is, for example, the optical axis misalignment detection unit 14 in FIG. 3, and based on the distance to the overhead sign specified by the specifying means, the installation height of the overhead sign stored in advance and the object detection device The vertical displacement of the beam emitted from the laser radar 3 is calculated using the height of the vehicle installed on the vehicle.
[0018]
The first determination means for determining whether or not the deviation detected by the detection means is within a predetermined range, and the first determination means determines that the deviation is not within the predetermined range. In this case, it is possible to further include alarm means for issuing an alarm.
[0019]
The first determination means is, for example, the optical axis deviation detection unit 14 of FIG. 3, and whether or not the deviation of the beam emission direction detected by the detection means is within a predetermined range set in advance. Judging. The predetermined range is a measurement error that is considered to be practically acceptable when the object detection device calculates the distance to the object on the road surface if the deviation in the emission direction is within the range, It is the range where the distance can be calculated.
[0020]
The alarm means is, for example, the alarm presentation unit 16 in FIG. 3, and when the first determination means determines that the deviation is not within a predetermined range, a corresponding indicator is displayed or a sound is output. To inform the driver that the object detection device is not operating normally.
[0021]
By doing so, it is possible to notify the driver that the object detection device has not normally measured the distance to the object, and accidents caused by this can be prevented in advance.
[0022]
Based on the measuring means for measuring the speed of the vehicle in which the object detection device is installed and the speed of the vehicle measured by the measuring means, it is determined whether or not the vehicle is traveling at a stable speed. A determination unit, and the detection unit may detect the shift when the second determination unit determines that the vehicle is traveling at a stable speed.
[0023]
The measuring means is, for example, the vehicle speed measuring device 21 in FIG. 3, and the second determining means is, for example, the control unit 11 in FIG. The control unit 11 determines whether the vehicle is traveling at a stable speed based on information on the traveling speed of the vehicle supplied from the vehicle speed measuring device 21, and when the vehicle is traveling at a stable speed. Only the deviation of the beam emission direction is calculated.
[0024]
In this way, when the vehicle is tilted (that is, when the object detection device attached to the vehicle is tilted), the process of calculating the deviation of the beam emission direction can be prevented. . Therefore, it is possible to prevent erroneous calculation of the deviation in the beam emission direction.
[0025]
The first object detection method of the present invention includes an emission step of emitting a beam, a reception step of receiving a reflected beam reflected by an object emitted by the processing of the emission step, and a process of the reception step. A measurement step for measuring the distance to the object that reflected the beam based on the received reflected beam, a recognition step for recognizing an overhead sign on the road surface based on the reflected beam received by the processing of the reception step, and recognition Based on the identification step for identifying the distance to the overhead marker immediately before the recognition of the overhead marker by the processing of the step, and the distance to the overhead marker identified by the processing of the specific step, And a detection step of detecting a deviation in the emission direction of the emitted beam.
[0026]
The emission step is, for example, step S1 in FIG. 4, the reception step is, for example, step S2 in FIG. 4, the measurement step is, for example, step S3 in FIG. 4, and the recognition step is, for example, This is step S4 of FIG. The specific step is, for example, step S6 in FIG. 4, and the detection step is, for example, step S7 in FIG.
[0027]
In the first object detection apparatus and method of the present invention, a beam is emitted, a reflected beam that is reflected when the emitted beam hits an object is received, and an object that reflects the beam based on the received reflected beam is received. The distance to the overhead sign immediately before the overhead sign on the road surface is recognized and recognition of the overhead sign becomes impossible is determined based on the received reflected beam. Based on the distance to the sign, a deviation in the emission direction of the emitted beam is detected.
[0029]
The emitting unit and the receiving unit are, for example, the laser radar 3 in FIG. 3, which emits a beam and receives a reflected beam reflected by a road surface and an object on the road surface. The measurement means is, for example, the object recognition / distance measurement unit 13 in FIG. 3, and calculates the distance to the object based on the reflected beam received by the reception means. The discriminating means is, for example, the object recognition / distance measuring unit 13 in FIG. 3, and judges whether or not the reflected beam received by the receiving means is a reflected beam from the road surface.
[0030]
The identification means is, for example, the object recognition / distance measurement unit 13 in FIG. 3, and when the determination means determines that the reflected beam is from the road surface, from the plurality of data measured by the measurement means to the road surface Identify data about distance.
[0031]
The detection means is, for example, the optical axis misalignment detection unit 14 in FIG. 3, and uses the installation height of the object detection device stored in advance in the vehicle based on the distance to the road surface specified by the specification means. Then, the deviation of the emission direction of the beam emitted from the laser radar 3 is calculated.
[0037]
The measuring means is, for example, the vehicle speed measuring device 21 in FIG. , The judging means is, for example, the control unit 11 in FIG. The control unit 11 determines whether the vehicle is traveling at a stable speed based on information on the traveling speed of the vehicle supplied from the vehicle speed measuring device 21, and when the vehicle is traveling at a stable speed. Only the deviation of the beam emission direction is calculated.
[0038]
In this way, when the vehicle is tilted (that is, when the object detection device attached to the vehicle is tilted), the process of calculating the deviation of the beam emission direction can be prevented. . Therefore, it is possible to prevent erroneous calculation of the deviation in the beam emission direction.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
The structural example of the target object detection apparatus 2 of this invention is demonstrated with reference to the block diagram of FIG.
[0042]
The control unit 11 of the object detection device 2 controls each part of the object detection device 2 based on a predetermined control program set in advance to determine the presence or absence of a preceding vehicle or to detect the preceding vehicle 5. In such a case, the inter-vehicle distance from the preceding vehicle 5 is measured to determine whether the inter-vehicle distance is a safe distance. If the inter-vehicle distance is not a safe distance, a series of processing for issuing a warning to the driver is executed. Further, when information indicating that the overhead sign (or road surface) has been confirmed is input from the object recognition / distance measurement unit 13, the control unit 11 receives the vehicle 1 supplied from the vehicle speed measurement device 21. Referring to the information on the traveling speed, it is determined whether the vehicle 1 is traveling at a stable speed (whether it is not accelerating or not) and is stable (running at a constant speed). If it is determined that there is an optical axis deviation, a predetermined process for detecting an optical axis shift described later is executed.
[0043]
The laser radar 3 outputs laser light 4 based on the control of the control unit 11, receives reflected light from an object such as an overhead sign or a preceding vehicle 5, and a reflector such as a road, and performs photoelectric conversion to obtain a signal. Input to the processing unit 12. The signal processing unit 12 performs predetermined signal processing on the laser light 4 output from the laser radar 3 and the signal corresponding to the reflected light, and supplies the signal processing to the object recognition / distance measurement unit 13.
[0044]
Based on the signal supplied from the signal processing unit 12, the object recognition / distance measurement unit 13 identifies a reflector such as an overhead sign, the preceding vehicle 5, and a road, and measures and controls the distance to the reflector. To the unit 11, the optical axis deviation detection unit 14, and the safety distance determination unit 15.
[0045]
The optical axis deviation detection unit 14 performs a predetermined calculation based on the distance to the reflector input from the object recognition / distance measurement unit 13 and calculates a deviation of the optical axis of the laser beam 4 from the reference direction. When it is determined that the deviation of the optical axis is larger than a predetermined deviation angle set in advance, the alarm presentation unit 16 is instructed to issue an alarm. Here, the optical axis of the laser beam 4 will be described with reference to FIG.
[0046]
In FIG. 4, the laser beam 4 projected from the laser radar 3 has a predetermined width in the vertical direction, and its end (boundary of the range having available intensity) is respectively set at the upper end 31 of the laser beam. And the lower end 32 of the laser beam. When the angle formed by the laser beam upper end 31 and the laser beam lower end 32 is Θ, the bisector is the optical axis 33. The angle Θ is set in advance to a predetermined value.
[0047]
Returning to FIG. 3, based on the distance to the reflector input from the object recognition / distance measurement unit 13, the safe distance determination unit 15 determines whether the inter-vehicle distance from the preceding vehicle 5 is a safe distance. If it is determined that the distance is not safe, the alarm presentation unit 16 is instructed to issue an alarm.
[0048]
When an instruction from the optical axis deviation detection unit 14 or the safety distance determination unit 15 is input, the alarm presentation unit 16 issues a corresponding alarm.
[0049]
The vehicle speed measuring device 21 in FIG. 3 constantly measures the speed of the traveling vehicle 1 and supplies it to the control unit 11 of the object detection device 2.
[0050]
By the way, when the control unit 11 of the object detection device 2 determines that a predetermined time (for example, one day) has elapsed since the detection processing of the optical axis deviation was performed last time, a series of detection of the optical axis deviation. Start processing.
[0051]
Next, the optical axis deviation detection process will be described with reference to the flowchart of FIG.
[0052]
In step S <b> 1, the laser radar 3 projects laser light 4.
[0053]
In step S2, the laser radar 3 receives the reflected light reflected by the various objects (reflectors) on the road surface from the laser light 4 projected in step S1.
[0054]
In step S <b> 3, the laser radar 3 inputs a signal (reflection signal) corresponding to the reflected light received in step S <b> 2 to the signal processing unit 12. The object recognition / distance measurement unit 13 calculates the presence / absence of the object (reflector) and the distance to the object based on the reflected signal subjected to the predetermined signal processing in the signal processing unit 12.
[0055]
In step S <b> 4, the object recognition / distance measurement unit 13 determines whether or not the recognized object (reflector) is the overhead sign 41. The control unit 11 stands by until information indicating that the overhead marker 41 has been confirmed is input from the object recognition / distance measurement unit 13.
[0056]
FIG. 6A shows the relationship between the host vehicle 1 traveling from the left to the right and the overhead sign 41 in the figure. The laser radar 3 of the object detection device 2 installed in the own vehicle 1 projects laser light 4 in front of the own vehicle 1. As the host vehicle 1 travels, the overhead sign 41 (solid line in the figure) approaches from a distance and approaches the measurement range of the laser radar 3, the laser beam 4 is reflected by the overhead sign 41, and the laser radar 3 receives this reflected light. This signal is processed by the signal processing unit 12 and then input to the object recognition / distance measuring unit 13. The object recognition / distance measurement unit 13 recognizes that it is an overhead sign by comparing the input signal with a reference signal. The reference signal is measured and stored in advance by experiments or the like. When information indicating that the overhead marker 41 has been recognized is input from the object recognition / distance measurement unit 13 to the control unit 11, the process proceeds to step S5.
[0057]
In step S <b> 5, the control unit 11 acquires the traveling speed of the host vehicle 1 from the vehicle speed measuring device 21, and based on that, the host vehicle 1 is traveling at a stable speed (a constant speed). If the vehicle is not traveling at a stable speed, the process returns to step S4 and the above-described process is repeated.
[0058]
In step S5, when the control unit 11 determines that the host vehicle 1 is traveling at a stable speed, the process proceeds to step S6, and the object recognition / distance measurement unit 13 determines whether the object recognition / distance measurement unit 13 is a laser. The distance between the laser radar 3 and the overhead sign 41 at the moment (immediately before) when the radar 3 cannot detect the overhead sign 41 is calculated. That is, in FIG. 6A, while the subject vehicle 1 travels in the right direction, the object recognition / distance measuring unit 13 continues to recognize the overhead sign 41, but the distance between the subject vehicle 1 and the overhead sign 41 is the overhead sign lost. When the distance is reached (when the overhead sign 41 is at the position indicated by the broken line (point indicated by ▲) in the figure), the overhead sign 41 comes out above the projection range of the laser beam 4, and the target object Thereafter, the recognition / distance measuring unit 13 cannot recognize the overhead marker 41 (this is referred to as lost). The object recognition / distance measuring unit 13 calculates the distance (the distance indicated by L1 in FIG. 6A) between the laser radar 3 and the overhead sign 41 immediately before the overhead sign 41 cannot be recognized, This is supplied to the shaft misalignment detector 14.
[0059]
In step S7, the optical axis deviation detection unit 14 calculates the optical axis deviation based on the distance L1 between the laser radar 3 and the overhead sign 41 calculated by the object recognition / distance measurement unit 13 in step S6. . Details of this processing will be described later.
[0060]
In step S8, the optical axis deviation detection unit 14 determines whether or not the deviation of the optical axis calculated in step S7 is within a predetermined range set in advance, and is within the predetermined range. The process is terminated.
[0061]
In step S8, when the optical axis deviation detecting unit 14 determines that the optical axis is greatly deviated from a predetermined range, the process proceeds to step S9, and the optical axis deviation detecting unit 14 notifies the warning presenting unit 16 to the driver. Command the alarm to be presented. In accordance with this command, the alarm presenting unit 16 displays an indicator indicating that the optical axis is shifted, or outputs a voice that indicates that the optical axis is shifted, for example. Informs that the axis is off.
[0062]
As described above, the object detection device 2 of the present invention performs a series of processes for detecting the deviation of the optical axis.
[0063]
For example, the installation position of the overhead sign 41 is recorded in advance on the recording medium of the car navigation system, and the optical axis deviation detection processing of the object detection device 2 is performed in conjunction with the car navigation system. Good. That is, when the car navigation system determines that there is an overhead sign 41 in front of the road on which the vehicle 1 is traveling, the information is supplied to the object detection device 2, and the optical axis is shifted to the object detection device 2. You may make it perform a series of processes which detect this. Also, information related to the installation height of the overhead sign 41 is recorded in advance on a recording medium of the car navigation system, and the installation height of the overhead sign 41 is calculated when the optical axis deviation detection unit 14 calculates the deviation of the optical axis. You may make it use the information regarding.
[0064]
Furthermore, a specific object on the road (for example, a signboard on the road other than the overhead sign 41 or the exit of the tunnel) is associated with the installation height and registered in the car navigation system in advance, thereby allowing the overhead sign. An object other than 41 may be used to detect an optical axis shift.
[0065]
In the above-described example, the laser beam is used as the beam for detection. However, the beam used by the object detection device 2 of the present invention is not limited to the laser beam.
[0066]
Next, the outline of the process of step S7 in FIG. 5, that is, the optical axis deviation detection process using the distance L1, will be described with reference to FIG.
[0067]
FIG. 7 shows the relationship between the own vehicle 1, the overhead sign 41, and the laser beam 4 at the moment when the laser radar 3 has lost the overhead sign 41. The distance L1 between the laser radar 3 and the overhead sign 41 is calculated by the process of step S6 of the object recognition / distance measurement unit 13. The installation height h of the laser radar 3 with respect to the road surface 64 has been measured in advance when the laser radar 3 is attached to the vehicle 1. As for the installation height H of the overhead sign 41, in Japan, the height of the lower end of the sign relative to the road surface 64 is set as a standard of 5 m (exception is 4.7 m to 6.0 m). The parallel line 51 is a convenience line drawn parallel to the road surface 64 at the installation height h of the laser radar 3.
[0068]
Here, when the projection port of the laser beam 4 of the laser radar 3 is a, the lower end of the overhead sign 41 is b, and the point where the perpendicular line and the parallel line 51 intersect from the lower end b to the road surface is c, the triangle abc is acb is a right triangle. The length of the side ab is L1, and the length of the side bc can be calculated by Hh.
[0069]
Therefore, when ∠bac is θ, the angle θ can be obtained by the following equation.
sinθ = (H−h) / L1
[0070]
Incidentally, as shown in FIG. 4, the optical axis 33 is a bisector of the angle Θ formed by the laser beam upper end 31 and the laser beam lower end 32.
[0071]
From the above, the angle formed by the optical axis 33 and the parallel line 51 can be obtained by θ−Θ / 2.
[0072]
An appropriate angle of the optical axis 33 with respect to the parallel line 51 when the object detection device 2 is installed in the host vehicle 1 is specified in advance within a predetermined range, and a value θ−Θ / 2 is specified in advance. By comparing with the appropriate angle, the vertical deviation of the optical axis 33 can be obtained.
[0073]
Next, FIG. 6B shows an example in which the optical axis is tilted upward from a predetermined range set in advance. Also in FIG. 6B, as in FIG. 6A, the host vehicle 1 travels from the left to the right in the figure. The laser radar 3 continues to recognize the approaching overhead sign 41. When the overhead recognition lost distance is reached (when the overhead marker 41 is in the position indicated by the broken line), the overhead marker 41 goes out of the field of view of the laser beam 4. At this time, the distance between the laser radar 3 and the overhead sign 41 is L2.
[0074]
As shown in the figure, the laser radar 3 when the optical axis shown in FIG. 6B is tilted upward as compared to the distance L1 between the laser radar 3 and the overhead sign 41 when the optical axis of FIG. 6A is normal. The distance L2 between the head mark 41 and the overhead sign 41 is short. By calculating the principle described above based on the distance L2, the deviation of the optical axis 33 is obtained. As a result, the magnitude of the deviation exceeds the range in which the object detection device 2 can operate normally. It is judged and a warning is displayed to the driver.
[0075]
Based on the principle as described above, the object detection device 2 of the present invention can detect the deviation of the optical axis 33.
[0076]
Next, a second example of the optical axis deviation detection method by the object detection apparatus 2 of the present invention will be described with reference to FIG. The principle of the optical axis deviation detection method is the same as that of the detection method using the overhead marker 41 shown in FIG. 7, and therefore detailed description will be omitted as appropriate in the following description.
[0077]
In the second example of the optical axis deviation detection method, the object detection device 2 uses the reflected light from the road surface 64 instead of using the reflected light from the overhead sign 41. As shown in FIG. 8, the laser beam 4 at the lower end 62 of the laser beam is reflected on the road surface 64 at a point e, and the reflected light is received by the laser radar 3. Based on the reflected light, the object recognition / distance measuring unit 13 identifies whether the light is reflected from the road surface 64, and the intersection of the projection port d, the laser light lower end 62, and the road surface 64 of the laser radar 3. A distance L3 between e is calculated. The object recognition / distance measuring unit 13 supplies the calculated distance L3 to the optical axis deviation detecting unit 14.
[0078]
Based on the distance L3 supplied from the object recognition / distance measuring unit 13 and the installation height h of the laser radar 3, the optical axis deviation detecting unit 14 calculates θ by the following equation.
[0079]
sinθ = h / L3
[0080]
Then, the optical axis deviation detection unit 14 calculates the angle of the optical axis 63 with respect to the parallel line 51 from the value obtained by subtracting Θ / 2 from θ (θ−Θ / 2).
[0081]
As described above, the object detection device 2 can also detect the deviation of the optical axis using the road surface 64. The above-described optical axis deviation detection method using the road surface 64 can detect a downward optical axis shift, and can also detect an upward optical axis shift up to a predetermined angle. is there.
[0082]
Whether or not the light is reflected from the road surface 64 can be determined by previously obtaining a feature value of a reflected signal based on the reflected light from the road surface 64 by experiment and comparing it with the feature value.
[0083]
In the present invention, by using the method as described above, it is possible to realize an object detection device having an optical axis deviation detection function without increasing the size of the device and without increasing the cost of the device. it can.
[0084]
In the above description, a laser beam is used. However, it is also possible to use a radio wave beam that can ensure a sufficiently sharp directivity such as a millimeter wave.
【The invention's effect】
As described above, according to the first object detection apparatus and method of the present invention, the distance to the overhead marker immediately before the overhead marker becomes unrecognizable is identified, and the distance to the identified overhead marker is determined. Since the deviation in the emission direction of the emitted beam is detected based on the above, it is possible to detect the deviation of the optical axis with high accuracy by a device having a simple configuration.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a method of detecting an object by a conventional object detection apparatus.
FIG. 2 is a diagram for explaining a deviation of an optical axis by a conventional object detection device.
FIG. 3 is a block diagram illustrating a configuration example of an object detection device of the present invention.
4 is a diagram for explaining an optical axis of laser light projected by the object detection device of FIG. 3; FIG.
FIG. 5 is a flowchart for explaining the operation of the object detection device of FIG. 3;
6 is a diagram for explaining an optical axis misalignment detection method of the object detection device of FIG. 3. FIG.
7 is another diagram for explaining an optical axis misalignment detection method of the object detection device of FIG. 3. FIG.
8 is a diagram for explaining another optical axis misalignment detection method of the object detection device of FIG. 3. FIG.
[Explanation of symbols]
1 Vehicle
2 Object detection device
3 Laser radar
4 Laser light
5 preceding car
11 Control unit
12 Signal processor
13 Object Recognition / Distance Measurement Unit
14 Optical axis deviation detector
15 Safety distance judgment part
16 Alarm presentation part
21 Vehicle speed measuring device
31 Upper end of laser beam
32 Lower end of laser beam
33 Optical axis
41 Overhead sign
51 parallel lines
61 Upper end of laser beam
62 Lower end of laser beam
63 Optical axis
64 road surface

Claims (4)

In an object detection device for detecting an object on a road surface,
Emitting means for emitting a beam;
Receiving means for receiving a reflected beam reflected by the beam emitted by the emitting means and hitting an object; and
Measuring means for measuring the distance to the object that reflected the beam based on the reflected beam received by the receiving means;
Recognizing means for recognizing an overhead sign on the road surface based on the reflected beam received by the receiving means;
Specifying means for specifying a distance to the overhead sign immediately before the recognition means becomes unable to recognize the overhead sign;
An object detection apparatus comprising: a detection unit configured to detect a deviation in an emission direction of the beam emitted by the emission unit based on a distance to the overhead marker identified by the identification unit. First determination means for determining whether or not the deviation detected by the detection means is within a predetermined range;
The object detection apparatus according to claim 1, further comprising: an alarm unit that issues an alarm when the first determination unit determines that the deviation is not within the predetermined range. Measuring means for measuring the speed of the vehicle in which the object detection device is installed;
A second determination means for determining whether or not the vehicle is traveling at a stable speed based on the speed of the vehicle measured by the measurement means; and
3. The object detection according to claim 1, wherein the detection unit detects the shift when the second determination unit determines that the vehicle is traveling at a stable speed. 4. apparatus. In an object detection method of an object detection device for detecting an object on a road surface,
An exit step for emitting the beam;
A receiving step of receiving a reflected beam reflected by the beam emitted by the processing of the emitting step and hitting an object;
A measurement step of measuring a distance to the object that reflected the beam based on the reflected beam received by the processing of the reception step;
A recognition step of recognizing an overhead sign on the road surface based on the reflected beam received by the processing of the reception step;
A specifying step for specifying a distance to the overhead sign immediately before the recognition of the overhead sign becomes impossible by the processing of the recognition step;
And a detection step of detecting a deviation in the emission direction of the beam emitted by the process of the emission step based on the distance to the overhead marker identified by the process of the identification step. Detection method.

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