JPH0862335A - Object detecting device - Google Patents

Abstract

PURPOSE: To ensure a stable detecting precision to the change of emitting condition of natural light in an object detecting device for vehicle for detecting the reflector of a forward vehicle. CONSTITUTION: A beam of a prescribed wavelength range is intermittently emitted from a LED array. The reflected light from the reflector of a forward vehicle is received by a camera having a filter for transmitting the beam on the light receiving surface. The light receipt signal before beam emission, the light emission signal at beam emission, and the light receipt signal after beam emission are taken as fn -1 , fn , and fn+1 , respectively. The two-stage difference of the light receipt signal g. is calculated by 2fn -fn -1 -fn+1 =gn . The area where gn is a prescribed value t1 or more and the area where it is less than t1 are grasped as a reflector area of preceding vehicle and a reflecting area of natural light, respectively, and only the reflector area is extracted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object detecting device,
In particular, the present invention relates to an object detection device suitable for detecting a reflector of a vehicle ahead as an object detection device for a vehicle.

[0002]

2. Description of the Related Art Conventionally, as an object detecting device for a vehicle, for example, as disclosed in Japanese Patent Laid-Open No. 3-5256, infrared light is pulsed and a preceding vehicle is detected based on the reflected light. The device is known.

That is, a reflector for reflecting the received light in the incident direction is usually arranged on the rear surface of the vehicle. Therefore, if infrared light is emitted from the following vehicle toward the preceding vehicle, the light is reflected from the reflector of the preceding vehicle toward the following vehicle. Therefore, by detecting the reflected light using a filter that transmits only infrared light, it is possible to determine the presence or absence of a preceding vehicle.

By the way, infrared light is also included in natural light such as sunlight. For this reason, when the vehicle is traveling under natural light, it is not necessary to emit infrared light from the following vehicle to the front, and the parts other than the reflector of the preceding vehicle, that is, the vehicle body of the preceding vehicle and the road installation Infrared light may be emitted toward the vehicle from an object or the like. Therefore, under such a situation, the presence or absence of the preceding vehicle cannot be determined only from the light reception signal received when the infrared light is emitted.

In the device described in the above publication, the infrared light is emitted in a pulsed light in view of this point.
That is, the reflected light caused by the above-described natural light or the like is light that is normally continuously generated. On the other hand, the reflected light that travels from the reflector of the preceding vehicle toward the following vehicle is light that is generated only when infrared light is emitted from the following vehicle.

Therefore, if the reflected light received when the infrared light is not emitted is subtracted from the reflected light received when the infrared light is emitted forward from the following vehicle, it is continuous. It is possible to remove the reflected light generated in the vehicle, and as a result, it is possible to detect only the reflected light from the reflector of the preceding vehicle.

Therefore, in the device described in the above publication,
Infrared light is emitted toward the front of the vehicle by pulsed light emission, and the first-order difference of the received light signal before and after the infrared light emission is taken to improve the detection accuracy of the preceding vehicle.

[0008]

However, the above-mentioned conventional object detecting device is based on the premise that the reflected light caused by natural light or the like is continuous light. On the other hand, under actual driving conditions, changes in the vehicle attitude of the preceding vehicle,
Reflected light such as natural light may suddenly disappear or may suddenly occur due to a change in the relative position between the vehicle and an on-road installation, the presence of a sunshade such as a tunnel, and the like.

In this case, if the disappearance timing or the occurrence timing coincides with the timing at which the infrared light is emitted forward from the following vehicle, the result of taking the first-order difference of the received light signal before and after the infrared light emission is obtained. , It becomes impossible to correspond to the reflected light emitted from the reflector of the preceding vehicle,
A situation may occur in which the presence or absence of a preceding vehicle is erroneously detected.

In this sense, the above-mentioned conventional object detecting device is
There is a problem that the presence / absence of a preceding vehicle may be erroneously determined when the generation state of reflected light changes.

The present invention has been made in view of the above points, and intermittently emits a beam in a predetermined wavelength region, and
An object detection apparatus that solves the above-mentioned problems by obtaining a second-order difference using a light reception signal before and after beam emission for a light reception signal at the time of beam emission, and determining the presence or absence of a preceding vehicle based on the result. The purpose is to provide.

[0012]

FIG. 1 is a block diagram showing the principle of an object detecting apparatus for solving the above problems. That is, the above-described object is, as shown by the solid line in FIG. 1, provided with an intermittent light emitting means M1 for intermittently emitting a beam in a predetermined wavelength range and a filter M2 for transmitting the beam emitted by the intermittent light emitting means M1 on the light receiving surface. In synchronization with the light emission timing of the means M3 and the intermittent light emission means M1, the light reception signal of the light reception means M3 before the beam emission is the first light reception signal, and the light reception signal of the light reception means M3 during the beam emission is the second light reception signal. A light receiving signal, a light receiving signal fetching means M4 for fetching the light receiving signal of the light receiving means M3 after the beam emission as a third light receiving signal, and the first and third light receiving signals before and after the second light receiving signal. This is achieved by an object detection device that includes a second-order difference calculation means M5 that calculates a second-order difference of a received light signal.

Further, as shown by a solid line and a broken line in FIG. 1, the above-mentioned object is, in the object detecting device according to claim 1, wherein the light receiving means M3 is constituted by a two-dimensional image sensor, and the second difference is As a result of the calculation by the calculating means M5, an area where the calculated value is less than the first judgment value, and the calculated value is equal to or larger than the first judgment value, and the calculated value is around the second judgment value.
It is also achieved by an object detection device including an unnecessary area removing unit M6 that removes an area having an area that is less than or equal to the determination value of 1.

[0014]

In the invention of claim 1, the intermittent light emitting means M1 intermittently emits a beam in a predetermined frequency band at a predetermined timing. Further, the filter M2 transmits light in the frequency band.

On the other hand, natural light such as sunlight contains light in the same frequency band as the beam. Therefore, when the intermittent light emitting means M1 emits light, the light receiving means M3 directs the traveling direction of the reflected light of the beam and the light in the same wavelength band as the beam included in the natural light toward the light receiving means M3. When the intermittent light emitting means M1 does not emit light, the light whose traveling direction is the light receiving means M3 among the light in the same wavelength band as the beam included in the natural light is received.

On the other hand, the received light receiving means M4
Synchronizes with the light emission timing of the intermittent light emission means M1 and takes in the light reception signals received by the light reception means M3 at each timing as the first to third light reception signals. In this case, if the light receiving signal due to natural light is continuously detected, the first and third light receiving signals become light receiving signals including only the signal due to natural light, and the second light receiving signal is The received light signal includes the signal caused by the beam.

Further, the second-order difference calculating means M5 calculates the second-order difference of the light receiving signal using the first and third light receiving signals before and after the second light receiving signal. In this case, assuming that the received light signal caused by natural light is continuously detected, if the second difference is obtained by subtracting the first and third received light signals from the result of doubling the second received light signal, Only the received light signal caused by the beam remains in the calculation result, and the received light signal caused by the natural light and the received light signal caused by the beam can be distinguished.

Further, when the received light signal due to natural light suddenly occurs at the emission start timing of the beam or suddenly disappears at the emission stop timing of the beam, the light receiving means M3 indicates the result of the second difference. A light reception signal equal to twice the light reception signal received due to the beam and a light reception signal which is apparently smaller than the light reception signal received by the light receiving means M3 due to natural light remain. As a result, it is possible to distinguish the received light signal caused by natural light from the received light signal caused by the beam.

Therefore, in the object detecting device according to the present invention, it is possible to detect the object that reflects the beam with stable accuracy even when the irradiation condition of the natural light changes during the object detection. Become.

In the invention of claim 2, the light receiving means M3 comprising a two-dimensional image sensor receives a light receiving signal caused by the reflected light of the beam and a light receiving signal caused by natural light as two-dimensional image information. . Therefore, in the present invention, the light reception signal capturing means M4 and the light reception signal capturing means M4
The processing of the floor difference calculation means M5 is also performed on the two-dimensional image information.

In this case, if the relative position between the object reflecting the natural light or the beam and the light receiving means M3 changes, the light receiving position on the light receiving means M3 changes following the change.

At this time, since the received light signal due to the beam is a signal contained only in the second received light signal, the calculation result of the second difference affects the above-mentioned change in relative position. I will not receive it.

On the other hand, the received light signal resulting from the natural light is
This is a signal that can be included in all of the first to third light reception signals, and the relative displacement described above occurs, and as a result, the light reception means M
When the light receiving position on No. 3 changes, by taking the second-order difference of the light receiving signal, it is not possible to erase the signals that are not received in duplicate among all of the first to third light receiving signals among the signals due to natural light. Cause

On the other hand, the unnecessary area removing means M6
Is a region where the calculated value is less than the first judgment value as a result of the calculation by the second-order difference calculation means M5, and the calculated value is equal to or larger than the first judgment value and the calculated values are present around it. A region including a region having a second determination value or less is removed as an unnecessary region.

In this case, when the unnecessary area is removed by the unnecessary area removing means M6, there is a signal contained only in the second light receiving signal, and the first and third light receiving signals are present around it. Only the region where the signal contained in 1 does not exist remains, and when the above-described relative displacement occurs, the received light signal due to natural light is appropriately removed as an unnecessary region.

[0026]

2 is a block diagram of an object detecting apparatus according to an embodiment of the present invention. The object detection device of this embodiment is a device arranged to detect a preceding vehicle in a vehicle.

In FIG. 1, the LED array 10 is provided so as to emit a beam in a predetermined wavelength band toward the front of the vehicle, and is given an appropriate directivity. A drive circuit 12 is connected to the LED array 10, and a light emission signal is intermittently supplied at predetermined intervals.

Here, in this embodiment, for one frame of 33 ms, the light emission period is one frame and the stop period is seven.
As a frame, intermittent light emission is performed with 8 frames as one cycle. In this case, the temperature rise of the LED array 10 can be appropriately suppressed, and the LED array 10 can emit light with a sufficiently large intensity as compared with the case of continuous light emission.

The camera 14 is the LED array 10 described above.
It is arranged in front of the vehicle so as to receive the reflected light of the beam emitted from, and the reflected signal can be received as a two-dimensional signal.

On the front surface of the light receiving surface of the camera 14, L
An optical filter 16 that transmits only light in the same frequency range as the beam emitted from the ED array 10 is provided. Therefore, of the reflected light of the beam emitted from the LED array 10 and the light contained in the natural light, the camera 14 receives only the light in the same frequency band as the beam.

By the way, the object detecting apparatus of the present embodiment is
A beam is emitted intermittently from the ED array 10, and as will be described later, a desired object is detected by considering a signal received by the camera 14 when the beam is emitted and a signal received by the camera 14 when the beam is stopped. It is a device to perform.

For this reason, it is necessary to control the light emission timing of the LED array 10 and the image pickup frame of the camera 14 in synchronism with each other. As shown in FIG. It will supply signals.

The camera 14 has an image processing device 18
Is connected. The image processing device 18 is a camera 1
4 has a function of taking in the light reception signal received in 4 for each image pickup frame. In this embodiment, the LED is used.
The nth light received when the beam is emitted from the array 10.
The image of the frame and the images of the (n-1) th frame and the (n + 1) th frame, which are the images before and after the frame, are taken in as the light reception signal.

An object position calculation device 20 is connected to the image processing device 18, and after the desired processing is performed in the image processing device 18, the object position calculation device 20 displays the result of the image processing. Based on this, the position calculation of the beam reflection target object is performed.

By the way, the object detecting apparatus of the present embodiment is an apparatus configured for the purpose of detecting the preceding vehicle as described above, and its existence is recognized particularly by using the reflector provided on the back surface of the preceding vehicle. Is what you are trying to do.

That is, the reflector disposed on the rear surface of the vehicle is configured to emit reflected light in the same direction as the incident direction of the incident light, regardless of the positional relationship between the preceding vehicle and the following vehicle. The light emitted from the car is reflected as it is toward the following car.

Therefore, when the beam is emitted from the LED array 10 toward the preceding vehicle as described above, the reflected light is reflected toward the camera 14 as long as the preceding vehicle exists, which is relatively easy. It is possible to recognize its existence.

Furthermore, if only the reflector of the preceding vehicle can be detected as image information, the distance between the preceding vehicle and the preceding vehicle can be calculated by stereoscopically viewing the reflector with two cameras.

As described above, according to the structure in which the presence of the reflector of the preceding vehicle is used to detect its presence, it is possible to obtain high detection accuracy as the object detection device and further utilize the detection result of the reflector. Therefore, it is possible to realize a useful object detection device in a vehicle.

As described above, since the reflector installed in the vehicle has the characteristic of reflecting the light in the same direction as the incident light, in this embodiment, as shown in FIG.
The light receiving surface of the camera 14 is arranged in the center of the D array 10 to improve the light receiving efficiency of the reflected light of the beam emitted from the LED array 10.

By the way, the camera 14 receives the signal due to the reflected light from the reflector of the preceding vehicle and the natural light as described above. Therefore, when the preceding vehicle is present and the natural light that illuminates the camera 14 is not present, only the reflector 32 of the preceding vehicle 30 is imaged when the beam is emitted, as shown in FIG.

On the other hand, in the preceding vehicle 30, there are areas 34 and 36 that reflect natural light toward the camera 14, or in road installations such as guardrails, areas 38 that reflect natural light toward the camera 14. If it exists,
When the beam is emitted, as shown in FIG.
2, the natural light reflection areas 34, 36, and 38 are attached to the camera 1.
It is imaged by 4.

Therefore, in such a case, the reflector of the preceding vehicle cannot be directly detected from the imaged image when the beam is emitted. In this case, the imaged image when the beam is emitted is required to detect the reflector. And an image captured when the beam is not emitted, that is, an image in which only the received light signal caused by natural light is captured.

In considering them together, in the method of taking the first-order difference between the imaged image at the time of beam emission and the imaged image before or after beam emission,
For example, due to changes in the vehicle attitude of the preceding vehicle, changes in the installation conditions of guardrails, etc., the natural light reflection regions 34, 3
As described above, when 6, 38 suddenly occur or disappear, accurate detection becomes difficult.

Therefore, in the present embodiment, a captured image at the time of beam emission, that is, an image of the nth frame,
Images before and after that, that is, the n-1th frame and the n + th frame
By obtaining the second-order difference of the received light signal using the image of one frame, it is possible to realize object detection that is stable against changes in the irradiation conditions of natural light toward the camera 14.

The specific contents of the method for obtaining the second difference will be described below with reference to FIG. That is, FIG.
Is the (n-1) -th frame, the n-th frame, the image captured in the camera 14 in the (n + 1) th frame f _n-1,
f _n, expressed as f _{n + 1,} the _{2f n -f n-1 -f n} + 1 g
_It is expressed as _n . In this case, g _n is the second difference of the received light signal in this embodiment.

In this case, the reflector 32 of the preceding vehicle should be imaged only when the beam is emitted, and should be contained only in f _n , while if the natural light reflection region is generated as continuous light, It should be contained in any of f _n-1 , f _n , and f _{n + 1} .

Therefore, when the second-order difference g _n is obtained as described above, the signal emitted from the natural light reflection region is erased, and as a result, the signal generated by the beam being reflected by the reflector (the region shown by hatching in FIG. 6). ) Will remain.

Furthermore, the irradiation condition of natural light toward the camera 14 changes in synchronization with the emission timing of the beam, and as a result, one of f _n-1 or f _{n + 1} does not contain a signal caused by natural light. Even in such a case, the signal due to natural light is subtracted at least once in the process of obtaining the second difference.

Therefore, even in such a situation, in g _n which is the result of the second-order difference, the signal due to the reflected light of the beam which is not subjected to any subtraction in the process of calculating the second-order difference and at least one subtraction are performed. Since the value is obviously different from the signal due to the natural light used for performing, the two can be easily distinguished by setting an appropriate determination value t ₁ .

In this sense, the method of the present embodiment, in which the second-order difference is calculated for the received light signal of the camera 14 and the presence of the reflector of the preceding vehicle is judged based on the calculation result, is applied to the change of the natural light irradiation condition. It is an extremely effective method for ensuring stable detection accuracy.

By the way, the camera 14 used in the object detecting apparatus of the present embodiment captures a two-dimensional image in front of the vehicle as described above. Therefore, if the relative positional relationship between the object to be imaged and the own vehicle changes, the same object will be imaged at different positions in the image in the (n−1) th frame, the nth frame, and the (n + 1) th frame.

In this case, the reflected light from the reflector is originally f
_{Since the} light is imaged only in _n , even if such a relative positional change occurs, it is not affected at all, but there is a problem with continuous light due to natural light.

That is, as shown in FIG. 7, the continuous light caused by the natural light is the (n-1) th frame, the nth frame, the nth frame.
Imaged at a slightly different position in +1 frame, g
_{At n} , it is not possible to eliminate all signals due to natural light. Thus, under such circumstances, it would cause problems that can not be extracted signal due to the reflected light directly reflector from the calculation results of g _n.

However, as shown in FIG. 7, when a signal due to natural light remains in g _n , a region where the calculated value is always negative is generated around it. Therefore, _if a region in which the calculated value is negative is detected in g _n and the peripheral region is captured as one unit and treated as an unnecessary region, it is possible to eliminate the signal caused by continuous light from within g _n. is there.

Therefore, in the present embodiment, in a region _where the calculation result of g _n is _equal to or larger than a predetermined judgment value t ₁ (> 0), the calculation value is surrounded by a predetermined judgment value −t ₂ (≦ It is decided to deal with the case where the natural light reflection area moves in the image by treating the area having the area of 0) or less as an unnecessary area.

FIG. 8 is a flowchart of an example of an object position output routine executed by the image processing device 18 and the object position calculation device 20 so as to realize the above-mentioned functions. Hereinafter, the operation of the object detection device according to the present embodiment will be described in detail with reference to FIG.

When the routine shown in FIG. 8 is started, first, at step 100, the camera 14 causes the image processing apparatus 1 to operate.
Image input to 8 is performed. In this step, as described above, the images at the (n-1) th frame, the nth frame, and the (n + 1) th frame are input with the image at the time of beam emission as the center.

FIG. 9 and FIG. 10 exemplify input images when the preceding vehicle existing in front of the camera 14 does not move in the captured image and when it moves. Incidentally, FIG.
10 and 10 show a state in which natural light reflection regions 34 and 36 are generated near the roof on the rear surface of the vehicle and in the center of the vehicle.

In step 102, the above-described second-order difference image is calculated based on the three input images. As a result, when the preceding vehicle is not moving in the captured image, an image in which only the reflector region 32 of the preceding vehicle remains is obtained as shown in FIG. 9, and when the preceding vehicle is moving in the captured image, As shown in FIG. 10, an image in which the reflector region 32 of the preceding vehicle and the natural light reflection regions 34 and 36 that carry the region where the calculated value is negative around them are left is obtained.

Next, at step 104, an area in which the calculated value is the judgment value t ₁ or more is detected from the obtained image.
This is for extracting a region in which a relatively high calculated value is obtained from the second-order difference image. Incidentally, as a result of such processing, FIG.
In FIG. 10, the reflector region 32 is detected in the second-order difference image, and in FIG. 10, the reflector region 32 and the natural light reflection regions 34, 36 are detected in the second-order difference image in which the high calculation value remains. Will be.

In step 106, the above step 104
In the region where the calculated value is greater than or equal to the determination value t ₁ , the region carrying a portion where the calculated value is less than or equal to the determination value −t ₂ within the radius r is removed. Figure 10
Natural light reflection regions 34, 3 in the second-order difference image shown in FIG.
This is to remove a region in which a high calculated value remains due to the movement of the reflection target object in the image, as shown in FIG.

As a result, even in the situation shown in FIG.
As in the case of FIG. 9, only the reflector region 32 of the preceding vehicle remains in the obtained image, and in any case, the reflector of the preceding vehicle can be detected appropriately.

After that, the object position calculating device 20 performs the processing from step 108 onward. Here, step 108 is a step of labeling each area remaining in the image obtained as a result of the above-mentioned processing as one unit.

Further, step 110 is a step of calculating the barycentric position with respect to the area labeled with a single label, and step 112 is a step of outputting the calculated barycentric position as the position of the object. As a result, in this embodiment, the position of the reflector of the preceding vehicle is output as long as the preceding vehicle is present in front of the object detection device.

As described above, according to the object detecting apparatus of this embodiment, the reflector is stable with respect to the natural light irradiation condition and is not affected by the change in the relative positional relationship between the preceding vehicle and the own vehicle. It is possible to detect the position of the vehicle with high accuracy and is highly useful as an object detection device for detecting the presence or absence of a preceding vehicle in the vehicle.

In the present embodiment, the LED array 1
0 and the drive circuit 12 to the intermittent light emitting means M1 described above, the camera 14 to the light receiving means M3 described above, the image processing device 18
Corresponds to the above-mentioned second-order difference calculation means M5 and unnecessary area removal means M6, respectively.

Further, in this embodiment, the received light signals f _n-1 , f _n , and f _{n + 1} in the (n-1) th frame, the nth frame, and the (n + 1) th frame are respectively described above. The determination values t ₁ and −t ₂ described above correspond to the above-described first determination value and second determination value, respectively.

By the way, in the above-mentioned embodiment, the light receiving means M is used.
Although the camera 14 capable of picking up a two-dimensional image is used as 3, the present invention is not limited to this, and in the case of merely detecting the presence or absence of a preceding vehicle, a phototransistor or the like is used as the light receiving means M3. It is also possible to use a light receiving element.

On the other hand, in the above-mentioned embodiment, only one camera 14 is used as the light receiving means M3. However, two cameras are used and the preceding vehicle is stereo driven as shown in FIGS. 11 (A) and 11 (B). If viewed, it is also possible to calculate the inter-vehicle distance to the preceding vehicle based on the parallax in those images.

Note that FIG. 11 shows an upper image obtained by the camera disposed above in the vehicle in FIG. 11A and obtained by a camera disposed below in the vehicle in FIG. 11B. The images below are shown respectively.

FIG. 12 is a flow chart of an example of a routine that realizes such a function when two cameras are connected to the image processing device 18. In the figure, steps that execute the same processing as the steps shown in FIG. 8 are given the same reference numerals and explanations thereof are omitted.

That is, when the routine shown in FIG. 12 is started, first, similarly to the routine shown in FIG. 8, a process for creating an image in which only the reflector region of the preceding vehicle remains is performed in steps 100 to 106.

Here, in this embodiment, in order to accurately perform the subsequent processing, as shown in FIG. 11, a window having a predetermined width is set for the image obtained as described above. In order to measure the distance to the preceding vehicle from the stereoscopic results of the two cameras, it is necessary to properly correspond the objects captured in each image. This is because each image should be compared.

Therefore, in this routine, if desired images are obtained for the upper image and the lower image by executing the steps 100 to 106, in step 200, each window is set for each image. Then, the labeling process similar to step 108 in FIG. 8 is performed for each window.

When the labeling process is completed, the process proceeds to step 202, and the barycentric position is calculated for each image with respect to the area labeled the same for each window.

Thereafter, in step 204, the parallax between the upper and lower images is calculated from the position of the center of gravity for each label in each window, then in step 206, the distance from the preceding vehicle is calculated from the parallax, and in step 208, The position of the detected object and the distance to the preceding vehicle are output, and the routine of this time is ended.

In this case, not only the presence or absence of the preceding vehicle but also the inter-vehicle distance to the preceding vehicle can be accurately detected. In this routine, since the windows are set for the upper image and the lower image as described above, when a plurality of preceding vehicles are captured in the image of the camera as shown in FIG. Can accurately detect the inter-vehicle distance from each preceding vehicle.

[0079]

As described above, according to the invention described in claim 1, for the signal received by the light receiving means, the second-order difference before and after the light receiving signal when the beam is emitted by the intermittent light emitting means is obtained. That eliminates the effect of natural light.

Therefore, even when the natural light irradiation condition changes in synchronization with the light emission timing of the intermittent light emitting means, its influence can be accurately eliminated, and only the reflected light of the beam can be properly detected. .

Therefore, according to the object detecting apparatus of the present invention, compared to the case where the object detection is performed based on the first-order difference of the received light signal, the detection accuracy is stable against variations in the natural light irradiation conditions. Objects that reflect the beam can be detected.

According to the second aspect of the invention, even when the relative position between the object to be reflected by the beam and natural light and the light receiving means is changed, the light receiving signal caused by the natural light can be appropriately removed. .

Therefore, the present invention enables stable object detection with respect to changes in natural light irradiation conditions as in the case of the first aspect of the present invention, and also provides stable accuracy for objects whose relative position changes. It has the feature that it can realize an object detection device that can detect it.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of an object detection device according to the present invention.

FIG. 2 is a block configuration diagram of an object detection device according to an embodiment of the present invention.

FIG. 3 is a diagram showing an arrangement of an LED array and a camera in this embodiment.

FIG. 4 is an example of a captured image in this embodiment.

FIG. 5 is another example of a captured image in the present embodiment.

FIG. 6 is a diagram for explaining a method of obtaining a second-order difference image in the present embodiment.

FIG. 7 is a diagram illustrating a method of obtaining an image in which an unnecessary area is removed in the present embodiment.

FIG. 8 is a flowchart of an example of a routine executed in this embodiment.

FIG. 9 is a diagram (No. 1) for explaining the content of image processing in the object detection device of the present embodiment.

FIG. 10 is a diagram (No. 2) for explaining the contents of image processing in the object detection device of the present embodiment.

FIG. 11 is an example of an image obtained when stereoscopic viewing is performed using two cameras.

FIG. 12 is a flowchart of another example of a routine executed in the object detection device of this embodiment.

[Explanation of symbols]

 M1 intermittent light emitting means M2, 16 filter M3 light receiving means M4 light receiving signal capturing means M5 second difference calculating means M6 unnecessary area removing means 10 LED array 12 drive circuit 14 camera 18 image processing device 20 object position calculating means 32 reflector area 34, 36 , 38 Natural light reflection area

Claims (2)

[Claims] 1. An intermittent light emitting means for intermittently emitting a beam in a predetermined wavelength range, a light receiving means having a light receiving surface with a filter for transmitting a beam emitted by the intermittent light emitting means, and a light emitting timing of the intermittent light emitting means. A light receiving signal of the light receiving means before the beam emission, a second light receiving signal of the light receiving means during the beam emission, and a third light receiving signal of the light receiving means after the beam emission. Light receiving signal capturing means for respectively capturing as a signal, and second-order difference calculating means for calculating a second-order difference of the light receiving signal using the first and third light receiving signals before and after the second light receiving signal. Object detection device. 2. The object detecting device according to claim 1, wherein the light receiving unit is configured by a two-dimensional image sensor, and a calculation value obtained by the second-order difference calculating unit has a first calculated value.
And the region where the calculated value is equal to or larger than the first judgment value and the region around which the calculated value is equal to or smaller than the second judgment value exists as unnecessary regions. An object detection device comprising: an unnecessary area removing unit for removing the unnecessary area.