JP3789757B2 - Object detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an object detection apparatus and method for detecting whether or not a predetermined object (including a person) is present in a predetermined monitoring area.
[0002]
[Prior art]
In various applications, it is required to detect whether a predetermined object exists within a predetermined monitoring area. For example, when a visually handicapped person enters the monitoring area, it is required to detect whether the visually handicapped person exists in a predetermined area in order to issue an alarm or guide the current position. .
[0003]
Conventionally, based on such a demand, for example, an object detection device disclosed in Japanese Patent Laid-Open No. 9-80165 has been provided. The object detection apparatus includes: an irradiation unit that collectively irradiates light of a predetermined wavelength region over the entire predetermined monitoring region; a CCD camera that captures an image of the monitoring region using light of the predetermined wavelength region; and a CCD camera. Based on the obtained image signal, it is determined whether or not a retroreflective material that is provided in advance on an object to be detected and retroreflects light in the predetermined wavelength region is present in the monitoring region. A determination unit for determining.
[0004]
According to this object detection apparatus, the retroreflective material has a characteristic of reflecting (retroreflecting) high-intensity light only in the substantially same direction as the direction of the irradiation light, so the image of the retroreflective material captured by the CCD camera The brightness of is high. For this reason, the image of the retroreflective material can be easily extracted from the background due to the luminance difference. Therefore, there is no need for an advanced image processing circuit or the like, and an object can be detected with high accuracy with a relatively simple configuration.
[0005]
[Problems to be solved by the invention]
However, although the conventional object detection apparatus does not require an advanced image processing circuit or the like, an imaging means such as a CCD camera is necessary, and thus the cost increase cannot be avoided.
[0006]
Therefore, it is conceivable to use a light receiving element such as a photodiode instead of a CCD camera or the like. However, in this case, if the entire monitoring area is irradiated with irradiation light as in the conventional object detection device, not only the reflected light (signal light) reflected from the retroreflective material but also the monitoring area Reflected light from most regions where no retroreflecting material exists (reflected light from the ground, wall surface, or other reflecting material, that is, noise light) is simultaneously received by the light receiving element. Therefore, the S / N is greatly reduced, and the detection accuracy is greatly reduced.
[0007]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an object detection apparatus that can reduce the cost without using an imaging unit and has high detection accuracy.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, an object detection apparatus according to a first aspect of the present invention includes an irradiation unit that irradiates a plurality of individual regions within a predetermined monitoring region, and an object to be detected. A light receiving means for receiving reflected light from a retroreflective material provided in advance for retroreflecting the beam, and the retroreflective material within the monitoring area based on a signal from the light receiving means. Determination means for determining whether or not it exists, the irradiation means, two or more of the plurality of beams at different timings, as different modulation lights, or Irradiation is performed at different timings and as different modulated lights.
[0009]
According to the first aspect, since the light receiving means is used instead of the imaging means, the cost can be greatly reduced as compared with the conventional object detection apparatus.
[0010]
In this first aspect, in use, a retroreflecting material that retroreflects light in a predetermined wavelength region irradiated by the irradiation means is provided in advance on the object to be detected. As described above, the retroreflective material has a characteristic of reflecting (retroreflecting) high-intensity light only in substantially the same direction as the direction of irradiation light.
[0011]
Accordingly, since the irradiation unit irradiates a plurality of individual beams in each of the individual areas in the monitoring region, if the retroreflective material exists in the monitoring region, the light receiving unit is provided with high brightness from the retroreflective material. The reflected light is received.
[0012]
And in the said 1st aspect, unlike the said conventional object detection apparatus, an irradiation means does not irradiate the same light to the whole monitoring area | region collectively, but irradiates a some individual area | region with several beams, respectively. Then, two or more of the plurality of beams are irradiated at different timings, as different modulation lights, or as different modulation lights at different timings. Therefore, in the first aspect, a region irradiated with the same modulated light or non-modulated light at the same timing is limited to a part of the monitoring region. Therefore, according to the first aspect, the noise light (ground, wall surface, etc.) received indistinguishably from the signal light together with the reflected light (signal light) reflected from the retroreflecting material by the light receiving means. The reflected light from the reflector is reduced. As a result, S / N is improved and detection accuracy is increased.
[0013]
Thus, according to the first aspect, the cost can be reduced without using the imaging means, and the detection accuracy can be increased.
[0014]
The object detection apparatus according to a second aspect of the present invention is the object detection apparatus according to the first aspect, wherein the predetermined monitoring region is a band-shaped region, and the irradiation unit includes the individual regions irradiated with the plurality of beams, respectively. The plurality of beams are radiated so as to be partially overlapped or aligned without overlapping substantially along the extending direction of the band-shaped region.
[0015]
According to the second aspect, since the monitoring area is a band-shaped area, it is possible to detect an object that has attempted to pass through the band-shaped area and to reduce the number of beams irradiated by the irradiation unit. The irradiation means can be configured at a lower cost. In addition, since the plurality of beams are irradiated so that the individual regions irradiated with the plurality of beams are arranged substantially without any gap along the direction in which the band-shaped region extends, it is possible to prevent omission of detection of an object. be able to.
[0016]
But in the said 1st aspect, the monitoring area | region is not limited to a strip | belt-shaped area | region, For example, it is good also as areas, such as a square, as needed.
[0017]
In the second aspect, for example, the monitoring region may extend linearly, in a V shape, in an L shape, in an arc shape, or in a circular shape within a horizontal plane having a predetermined height. This is a specific example of the monitoring area, but in the second aspect, the shape of the monitoring area is not limited to these examples, and can be appropriately determined according to the purpose.
[0018]
In the object detection apparatus according to the third aspect of the present invention, in the first or second aspect, the size of the individual area irradiated by each beam is just large enough to cover the retroreflective material. It is what is.
[0019]
If the size of the individual area is determined as in the third mode, the number of beams irradiated by the irradiation unit can be further reduced while further improving the S / N, which is preferable.
[0020]
In the object detection device according to a fourth aspect of the present invention, in any one of the first to third aspects, the irradiation unit irradiates the plurality of beams obliquely with respect to the vertical direction from above. is there.
[0021]
When the beam is irradiated obliquely with respect to the vertical direction from above as in the fourth aspect, for example, to give a warning to a visually handicapped person or guide guidance at a traffic light or a station platform In addition, when the object to be detected is a cane for a visually impaired person, the tip of the cane is inserted obliquely downward in the direction in which the visually impaired person advances, so that the cane only when it advances in a predetermined direction. Can also be detected. But in the said 1st thru | or 3rd aspect, you may irradiate the said several beam to the substantially perpendicular direction from upper direction.
[0022]
In the fourth aspect, for example, an inclination angle of the principal rays of the plurality of beams with respect to a vertical direction may be 20 ° or more and 40 ° or less. When the tilt angle is set in this way, for example, when the object to be detected is a cane for a visually impaired person, the retroreflective material provided on the cane can be made difficult to hide in the shadow of another person. It is more preferable to detect the staff only when traveling in a predetermined direction. The tilt angle is more preferably 25 ° or more and 35 ° or less.
[0023]
The object detection apparatus according to a fifth aspect of the present invention is the object detection device according to any one of the first to fourth aspects, wherein the irradiation unit is a plurality of light emitting elements each serving as a light source of the plurality of beams. A plurality of light emitting elements divided into groups, and a plurality of lens portions provided corresponding to the plurality of groups, respectively, and beams emitted from the light emitting elements of each group are the same lens corresponding to the group Each of the individual areas is irradiated after passing through the section.
[0024]
According to the fifth aspect, since the number of lens portions can be reduced, the configuration can be simplified and the cost can be further reduced, and the arrangement of a plurality of beams as in the second aspect is easy. Can be realized.
[0025]
The object detection device according to a sixth aspect of the present invention is the object detection device according to any one of the first to fifth aspects, wherein the light receiving means includes a single light receiving element and a lens unit disposed in front of the light receiving element. It consists of
[0026]
According to the fifth aspect, the configuration of the light receiving means is simplified, and the cost can be further reduced.
[0027]
In the object detection device according to a seventh aspect of the present invention, in any one of the first to fourth aspects, the light receiving unit includes a light receiving element and a lens unit disposed in front of the light receiving element. The irradiating means is disposed at a plurality of light emitting elements respectively disposed on both sides of the light receiving element, a front part of the light emitting element disposed on one side, and a front part of the light emitting element disposed on the other side. A plurality of light emitting elements disposed on one side of the light receiving element and irradiated with a plurality of individual regions, and a plurality of light emitting elements disposed on the other side of the light receiving element. The individual regions irradiated with a plurality of beams emitted from the light emitting elements are alternately arranged.
[0028]
According to the seventh aspect, the number of lens portions can be further reduced, and the cost can be further reduced, and the arrangement of a plurality of beams as in the second aspect can be easily realized. Can do.
[0029]
The object detection apparatus according to an eighth aspect of the present invention is the object detection device according to any one of the first to seventh aspects, wherein the irradiation unit irradiates each beam in a pulse shape a plurality of times during each beam generation period. The means determines the determination based on whether or not the number of pulses in which the level of the signal from the light receiving means corresponding to the pulse of the beam is equal to or higher than a predetermined level in each beam generation period is equal to or higher than a predetermined number. Is to do.
[0030]
According to the eighth aspect, the detection accuracy can be further increased.
[0031]
In any one of the first to eighth aspects, the plurality of beams may be light in a near-infrared wavelength region, for example. When light in the near-infrared wavelength region is used in this way, it becomes possible to distinguish from visible light or the like, so that the detection accuracy can be further increased.
[0032]
In any one of the first to eighth aspects, the plurality of beams may be modulated light, for example. When modulated light is used in this way, it becomes possible to distinguish from sunlight or the like, so that the detection accuracy can be further increased even outdoors.
[0033]
An object detection apparatus according to a ninth aspect of the present invention is the object detection apparatus according to any one of the first to eighth aspects, wherein the object is a cane for a visually impaired person.
[0034]
The ninth aspect is an example of a preferable detection target, but the first to eighth aspects may be used for detecting other various objects.
[0035]
In the object detection method according to the tenth aspect of the present invention, a predetermined monitoring area is divided into a plurality of individual areas, each of the plurality of individual areas is irradiated with a plurality of beams, and the object to be detected is provided in advance. The reflected light from the retroreflective material that retroreflects the beam is received by the light receiving means, and the retroreflective material exists in the monitoring area based on the signal from the light receiving means. An object detection method for determining whether or not two or more of the plurality of beams are different from each other at different timings, as different modulation lights, or at different timings. Irradiated as modulated light.
[0036]
According to the tenth aspect, the same advantages as in the first aspect can be obtained.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an object detection apparatus and method according to the present invention will be described with reference to the drawings.
[0038]
FIG. 1 is a schematic configuration diagram showing an object detection device 21 according to an embodiment of the present invention. FIG. 2 is a schematic longitudinal sectional view schematically showing an arrangement example of the object detection device 21 shown in FIG. FIG. 3 is a view taken along arrows AB in FIG. 2 showing only the first group of LEDs 1 to 6 and the first lens 31 corresponding thereto. FIG. 4 is a view taken along arrows AB in FIG. 2 showing only the second group of LEDs 7 to 12 and the second lens 32 corresponding to them. FIG. 5 is a view taken along arrows AB in FIG. 2 showing the LEDs 1 to 12 and the lenses 31 and 32. 6 is a view taken along the line CD in FIG. FIG. 7 is a view taken along the line EF in FIG.
[0039]
As shown in FIGS. 1 to 7, the object detection device 21 according to the present embodiment includes a first group of LEDs 1 to 6 and a second group of light emitting elements serving as light sources of a plurality of beams B1 to B12, respectively. LEDs 7 to 12 in the first group, first lenses 31 provided in front of them corresponding to the LEDs 1 to 6 in the first group, and fronts thereof corresponding to the LEDs 7 to 12 in the second group A single light-receiving element that receives the reflected light retroreflected by the retroreflective material 42 provided in advance on the second lens 32 provided in the lens and the visually-impaired cane 41 as the object to be detected. PIN photodiode 13, third lens 33 disposed in front of PIN photodiode 13, control unit 22, drive circuit 23, amplifier circuit 24, bandpass filter 25, and determination unit 26. , And a. In the present invention, the number of LEDs in each group, the type of light emitting element, the type of light receiving element, and the like are not particularly limited.
[0040]
In the present embodiment, infrared LEDs that emit light in the near-infrared wavelength region are used as the LEDs 1 to 12. Convex lenses are used as the lenses 31 to 33 and act as a condensing lens. In order to reduce the size of the apparatus, it is preferable to use a Fresnel lens as the lenses 31 to 33. For example, a lens array in which the lenses 31 to 33 are integrated can be used.
[0041]
As shown in FIG. 6, the first group of LEDs 1 to 6 are arranged in a straight line on one side of the PIN photodiode 13. The second group of LEDs 7 to 12 are arranged in a straight line on the other side of the PIN photodiode 13 in parallel with the columns of the first group of LEDs 1 to 6. By appropriately adjusting and setting the orientation of the individual LEDs 1 to 12, the focal length of the lenses 31 and 32, the positional relationship between the LEDs 1 to 6 and the lens 31, the positional relationship between the LEDs 7 to 12 and the lens 32, and the like. The beams B1 to B6 emitted from the LEDs 1 to 6 of the first group and passed through the lens 31 and the beams B7 to B12 emitted from the LEDs 7 to 12 of the second group and passed through the lens 32 are shown in FIGS. As shown in FIG. 5 and FIG.
[0042]
That is, as shown in FIG. 2, the beams B1 to B12 are irradiated obliquely with respect to the vertical direction from above. The inclination angle of the beams B1 to B12 with respect to the vertical direction is approximately 30 °. In FIG. 2, although the beams B1 to B12 are shown as parallel light beams, it goes without saying that the beams B1 to B12 may be diffused light beams. In addition, each irradiation region of the beams B1 to B12 in the horizontal plane P (see FIG. 2) having the same height as the height h of the retroreflective member 42 of the cane 41 is indicated by a circle on the right side in FIGS. At the same time, as shown by the circles in FIG. In FIG. 7, only the irradiation areas in the horizontal plane P are shown for the beams B1 to B12. The irradiation areas of the beams B1 to B6 in the horizontal plane P are arranged with a gap as shown in FIG. 3, and the irradiation areas of the beams B7 to B12 in the horizontal plane P are arranged with a gap as shown in FIG. As shown in FIG. 5 and FIG. 7, these irradiation regions are alternately arranged, so that they are partially overlapped without any gap in a straight line as a whole. However, the irradiation regions of the beams B1 to B12 in the horizontal plane P may be arranged without gaps and without overlapping, or may be arranged with some gaps.
[0043]
In the present embodiment, as described above, as shown in FIG. 6, the first group of LEDs 1 to 6 and the second group of LEDs 7 to 12 are arranged on both sides of the PIN photodiode 13. Therefore, the distance between each of the LEDs 1 to 12 and the PIN photodiode 13 is narrowed. For this reason, since the retroreflective member 42 has a characteristic of reflecting (retroreflecting) high-intensity light only in substantially the same direction as the direction of irradiation light, the PIN photodiode 13 is emitted from each of the LEDs 1 to 12. The reflected light retroreflected by the retroreflective material 42 can be received efficiently, which is preferable. Although not shown in the drawing, if an eccentric lens whose optical axis is decentered toward the PIN photodiode 13 is used as the lenses 31 and 32, the arrangement of the beams B1 to B12 as described above is realized and the LEDs 1 to 6 are arranged. The distance between the column and the PIN photodiode 13 and the distance between the column of the LEDs 7 to 12 and the PIN photodiode 13 can be further reduced, which is more preferable.
[0044]
In the present embodiment, the irradiation areas of the beams B1 to B12 in the horizontal plane P constitute a monitoring area as a whole. That is, in the present embodiment, the monitoring area is a linear belt-like area, and each irradiation area of the beams B1 to B12 in the horizontal plane P is an individual area in the monitoring area. In the present embodiment, each irradiation region of the beams B <b> 1 to B <b> 12 in the horizontal plane P has a size that just covers the retroreflective material 42. However, the size of each irradiation region is not limited to such a size.
[0045]
As shown in FIG. 8, the control unit 22 in FIG. This reference pulse is used as a modulation signal of the beams B1 to B12. Based on the reference pulse, the control unit 22 generates lighting control signals for controlling the lighting of the LEDs 1 to 12 as shown in FIG. 8, and supplies these lighting control signals to the drive circuit 23 and the determination unit 26. To do. In the present embodiment, as shown in FIG. 8, the lighting control signals of the respective LEDs 1 to 12 are obtained by sequentially distributing eight reference pulses in a cyclic manner. The drive circuit 23 drives the LEDs 1 to 12 according to the lighting control signals for the LEDs 1 to 12 supplied from the control unit 22. Therefore, when each lighting control signal in FIG. 8 is “high”, the LED corresponding to the lighting control signal is turned on, and the beam corresponding to the LED is irradiated. For this reason, in the present embodiment, the period of 8 pulses of the reference pulse is each beam generation period, and each of the beams B1 to B12 is irradiated in a pulse shape 8 times during the beam generation period. Irradiated as modulated light modulated by Further, the beams B1 to B12 are sequentially irradiated one by one, and are irradiated at different timings. Thus, in this embodiment, all the beams B1 to B12 are irradiated as the same modulated light at different timings. However, in the present invention, two or more of the beams B1 to B12 are different from each other. What is necessary is just to irradiate as a modulated light which is different at a timing, mutually different modulated light, or at a mutually different timing and mutually different.
[0046]
As can be seen from the above description, in the present embodiment, the LEDs 1 to 12, the lenses 31 and 32, the control unit 22, and the drive circuit 23 each have a plurality of beams in a plurality of individual regions within a predetermined monitoring region. The irradiation means which irradiates B1-B12 at a mutually different timing is comprised. Further, in the present embodiment, the PIN photodiode 13 and the lens 33 are retroreflective materials 42 provided in advance on a cane 41 as an object to be detected, and retroreflective materials 42 that retroreflect the beams B1 to B12. The light receiving means for receiving the reflected light from is constructed.
[0047]
The amplifying circuit 24 in FIG. 1 amplifies the light reception signal from the PIN photodiode 13. The band pass filter 25 filters only the signal having the frequency of the reference pulse with respect to the light reception signal amplified by the amplifier circuit 24. Thereby, noise components, such as sunlight, are removed. The light reception signal filtered by the band pass filter 25 is supplied to the determination unit 26.
[0048]
The determination unit 26 retroreflects based on the light reception signal filtered by the band pass filter 25 and the lighting control signals for the LEDs 1 to 12 from the control unit 22 (that is, the light emission timing signals of the LEDs 1 to 12). It is determined whether or not the material 42 is present in the monitoring area, and if it is present, a sensing signal (detection signal) is output.
[0049]
FIG. 9 is a schematic flowchart illustrating an example of the operation of the determination unit 26. In this example, when the operation starts, the determination unit 26 captures the light reception signal filtered by the band-pass filter 25 for one pulse in FIG. 8 in synchronization with the lighting control signals for the respective LEDs 1 to 12 ( Step S1). Next, the determination unit 26 determines whether or not the level of the received light signal acquired in step S1 is equal to or higher than a predetermined level, and further acquires the latest in step S1 based on the level determination result for each pulse up to now. In the beam generation period (period of 8 pulses in the present embodiment) to which the pulse in FIG. 8 corresponding to the received light reception signal belongs, the number of level determination results indicating that it is above a predetermined level (the light reception signal is above a predetermined level) (Corresponding to the number of pulses) is greater than or equal to a predetermined number of times (for example, 5 times) (step S2). If not the predetermined number of times or more, the process returns to step S1. On the other hand, if the number of times is greater than or equal to the predetermined number, a sensing signal indicating that the retroreflective member 42, that is, the wand 41 is present in the monitoring area is output.
[0050]
If the determination unit 26 performs the operation as shown in FIG. 9, it is preferable because the detection accuracy is increased. However, in the present invention, for example, in the step S2, the determination unit 26 determines the level of the received light signal in step S1. It is determined whether or not the level is equal to or higher than a predetermined level. If the level is equal to or higher than the predetermined level, a sensing signal may be output immediately. In addition, when the determination unit 26 outputs a sensing signal, a signal indicating which of the LEDs 1 to 12 is sensed based on the light emission timing signal of each LED 1 to 12 from the control unit 26 (Corresponding to the location information of the retroreflective material 42) may also be output.
[0051]
In addition, the control part 22 and the determination part 26 which perform the operation | movement mentioned above can be comprised using PLD (Programmable Logic Device), a microcomputer, etc., for example.
[0052]
According to the present embodiment, since the light receiving means including the PIN photodiode 13 and the lens 33 is used instead of the imaging means, the cost can be greatly reduced as compared with the conventional object detection apparatus.
[0053]
According to the present embodiment, since a plurality of beams B1 to B12 are irradiated to each of the plurality of individual regions in the monitoring region, as shown in FIG. If the retroreflective material 42 is present in the monitoring region, the PIN photodiode 13 receives the high-intensity reflected light from the retroreflective material 42.
[0054]
And in this Embodiment, unlike the said conventional object detection apparatus, rather than irradiating the whole monitoring area | region with the same light collectively, several beams B1-B12 are mutually different to several separate area | regions, respectively. Irradiate at the timing. Therefore, in the present embodiment, the areas irradiated with the same modulated light at the same timing are limited to a very small part of the monitoring area. Therefore, according to the present embodiment, noise light (ground, ground) received by the PIN photodiode 13 together with the reflected light (signal light) reflected from the retroreflective member 42 indistinguishably from the signal light. Light reflected from the wall and other reflecting objects) is greatly reduced. As a result, S / N is improved and detection accuracy is increased.
[0055]
As described above, according to the present embodiment, it is possible to reduce the cost without using the imaging means, and it is possible to increase the detection accuracy.
[0056]
Further, according to the present embodiment, since the monitoring area is a band-shaped area as described above, it is possible to detect the cane 41 that has attempted to pass through the band-shaped area and to determine the number of beams B1 to B12 to be irradiated. Therefore, the irradiation means can be configured at a lower cost. Moreover, since the plurality of beams B1 to B12 are irradiated so that the individual regions irradiated with the plurality of beams B1 to B12 are arranged substantially without any gap along the extending direction of the band-shaped region, It is possible to prevent 41 detection omissions.
[0057]
Furthermore, according to the present embodiment, as described above, each irradiation region (each individual region) of the beams B1 to B12 in the horizontal plane P is just large enough to cover the retroreflective material 42. The number of irradiated beams B1 to B12 can be reduced while further improving the S / N.
[0058]
Furthermore, according to the present embodiment, since the beams B1 to B12 are irradiated obliquely with respect to the vertical direction from above, the tip of the cane is pushed obliquely downward in the direction in which the visually impaired person proceeds. The cane 41 can be detected only when traveling in the predetermined direction X1. Therefore, it is suitable when performing guidance according to the traveling direction.
[0059]
This point will be described with reference to FIG. FIG. 10A shows a situation in which the person holding the cane 41 proceeds from the state shown in FIG. 2 in the direction of the arrow X1 and reaches the monitoring area. In this case, the cross-sectional area of the light beam that irradiates the retroreflective material 42 out of the beams B1 to B12 becomes large from the relationship between the inclinations of the retroreflective material 42 and the beams B1 to B12, and is reflected by the retroreflective material 42 and reflected by the PIN photo. Since the amount of light received by the diode 13 increases, the retroreflective material 42 is detected. FIG. 10B shows a situation where the person holding the cane 41 has advanced in the reverse direction (arrow X2) and has reached the monitoring area. In this case, the cross-sectional area of the light beam that irradiates the retroreflective material 42 out of the beams B1 to B12 becomes small due to the inclination relationship between the retroreflective material 42 and the beams B1 to B12, and is reflected by the retroreflective material 42 and reflected by the PIN photo. Since the amount of light received by the diode 13 is small, the retroreflective material 42 is not detected.
[0060]
In particular, in the present embodiment, the inclination angle of the beams B1 to B12 with respect to the vertical direction is approximately 30 °, which is preferable for detecting the cane 41 only when traveling in the predetermined direction X1, The retroreflective material 42 can be made difficult to hide in the shadows of other people. This inclination angle may be 20 ° or more and 40 ° or less, but is more preferably 25 ° or more and 35 ° or less.
[0061]
In addition, according to the present embodiment, one lens 31 is provided in common for the first group of LEDs 1 to 6, and one lens 32 is provided in common for the second group of LEDs 7 to 12. Therefore, the number of lenses can be reduced and the cost can be further reduced.
[0062]
Furthermore, according to the present embodiment, since the light receiving means is constituted by the single PIN photodiode 13 and the lens 33 arranged in front thereof, the structure of the light receiving means is simplified and the cost is further reduced. be able to.
[0063]
In the embodiment described above, the monitoring area is an example of a linear belt-shaped area. However, in the present invention, the monitoring area is, for example, a V-shaped, L-shaped, arc-shaped or circular belt-shaped area. It can be. The shape of the monitoring area can be appropriately determined according to the application.
[0064]
FIG. 11 shows an example in which the monitoring area is a circular belt-like area, and FIG. 12 shows an example in which the monitoring area is a V-shaped belt-like area. 11 and 12 are schematic plan views seen from above corresponding to FIG. 7 described above. Among the plurality of circles forming a circular or V-shaped row in FIGS. 11 and 12, the hatched circle is a beam irradiated from each LED of the first group through the first lens 31. Each of the irradiation areas (individual areas) in the horizontal plane P is indicated by an unhatched circle, and each of the beams irradiated from the LEDs of the second group through the second lens 32 is irradiated in the horizontal plane P. Each area (individual area) is shown.
[0065]
Referring to FIG. 6, in the case of FIG. 11, for example, in the object detection device 21, a plurality of LEDs of the first group are arranged in a circle and a plurality of LEDs of the second group are arranged in a circle. And the direction of these LEDs may be set as appropriate. In the case of FIG. 11, even if the person holding the cane 41 proceeds from any direction to the inside of the monitoring area, it can be detected.
[0066]
In the case of FIG. 12, for example, in the object detection device 21, a plurality of LEDs of the first group are arranged in a V shape, and a plurality of LEDs of the second group are arranged in a V shape. What is necessary is just to set the direction of these LED suitably.
[0067]
As mentioned above, although embodiment of this invention and its modification were demonstrated, this invention is not limited to these embodiment or modification.
[0068]
【The invention's effect】
As described above, according to the present invention, it is possible to reduce the cost without using the imaging means, and to provide an object detection device with high detection accuracy.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an object detection apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic longitudinal sectional view schematically showing an arrangement example of the object detection device shown in FIG.
FIG. 3 is a view taken along the line AB in FIG. 2 showing only the first group of LEDs and the first lens corresponding to them.
FIG. 4 is a view taken along the line AB in FIG. 2 showing only the second group of LEDs and the second lens corresponding to them.
FIG. 5 is a view taken along the line AB in FIG. 2 showing the first and second LEDs and the first and second lenses.
6 is a view taken along arrow CD in FIG. 2. FIG.
7 is a view taken along the line EF in FIG. 2;
FIG. 8 is a timing chart showing a reference pulse and a lighting control signal.
FIG. 9 is a schematic flowchart illustrating an example of an operation of a determination unit.
FIG. 10 is an explanatory diagram showing the presence or absence of detection due to a difference in traveling direction.
FIG. 11 is a schematic plan view seen from above showing an example in which the monitoring area is a circular belt-like area.
FIG. 12 is a schematic plan view seen from above showing an example in which the monitoring region is a V-shaped strip region;
[Explanation of symbols]
1-6 LED of the first group
7-12 Second group of LEDs
13 PIN photodiode
21 Object detection device
22 Control unit
23 Drive circuit
24 Amplifier circuit
25 Bandpass filter
26 judgment part
31, 32, 33 lenses
41 Cane
42 Retroreflective material

Claims (11)

Irradiating means for irradiating each of a plurality of individual regions within a predetermined monitoring region with a plurality of beams;
A light receiving means for receiving reflected light from a retroreflective material that is retroreflective material provided in advance on an object to be detected and retroreflects the beam;
Determination means for determining whether or not the retroreflective material is present in the monitoring region based on a signal from the light receiving means;
With
The irradiation means irradiates two or more of the plurality of beams at different timings, as different modulation lights, or as different modulation lights at different timings ,
The irradiation means includes a plurality of light emitting elements each serving as a light source of the plurality of beams, and a plurality of light emitting elements divided into a plurality of groups, and a plurality of lenses provided corresponding to the plurality of groups, respectively. A beam emitted from each group of light emitting elements irradiates the individual regions after passing through the same lens unit corresponding to the group . 2. The object detection apparatus according to claim 1, wherein the light receiving means includes a single light receiving element and a lens unit disposed in front of the light receiving element. Irradiating means for irradiating each of a plurality of individual regions within a predetermined monitoring region with a plurality of beams;
Light receiving means for receiving reflected light from a retroreflective material that is retroreflective material provided in advance on the object to be detected and retroreflects the beam;
Determining means for determining whether or not the retroreflective material is present in the monitoring region based on a signal from the light receiving means;
With
The irradiation means irradiates two or more of the plurality of beams at different timings, as different modulation lights, or as different modulation lights at different timings,
The light receiving means includes a light receiving element and a lens unit disposed in front of the light receiving element,
The irradiation means includes a plurality of light emitting elements disposed on both sides of the light receiving element, a front portion of the plurality of light emitting elements disposed on one side, and a front portion of the plurality of light emitting elements disposed on the other side, respectively. Two lens parts arranged,
The individual region irradiated with a plurality of beams emitted from a plurality of light emitting elements arranged on one side of the light receiving element, and a plurality of beams emitted from a plurality of light emitting elements arranged on the other side of the light receiving element The object detection apparatus, wherein the individual areas irradiated by the are arranged alternately. The irradiating means irradiates each beam in a plurality of times in each beam generation period, and the determination means has a signal level from the light receiving means corresponding to the pulse of the beam in each beam generation period. 4. The object detection apparatus according to claim 1, wherein the determination is performed based on whether or not the number of pulses equal to or higher than a predetermined level is equal to or higher than a predetermined number. Irradiating means for irradiating each of a plurality of individual regions within a predetermined monitoring region with a plurality of beams;
Light receiving means for receiving reflected light from a retroreflective material that is retroreflective material provided in advance on the object to be detected and retroreflects the beam;
Determining means for determining whether or not the retroreflective material is present in the monitoring region based on a signal from the light receiving means;
With
The irradiation means irradiates two or more of the plurality of beams at different timings, as different modulation lights, or as different modulation lights at different timings,
The irradiating means irradiates each beam in a plurality of times in each beam generation period, and the determination means has a signal level from the light receiving means corresponding to the pulse of the beam in each beam generation period. An object detection apparatus that performs the determination based on whether or not the number of pulses that are equal to or higher than a predetermined level is equal to or higher than a predetermined number. 6. The object detection apparatus according to claim 5, wherein the light receiving means includes a single light receiving element and a lens unit disposed in front of the light receiving element. The predetermined monitoring area is a band-shaped area, and the irradiation unit is configured such that the individual areas irradiated with the plurality of beams are partly without a gap along a direction in which the band-shaped area extends. The object detection apparatus according to claim 1, wherein the plurality of beams are irradiated so as to be arranged without overlapping or partially overlapping. The object detection apparatus according to any one of claims 1 to 7, wherein the size of the individual area irradiated by each beam is just large enough to cover the retroreflective material. The object detection apparatus according to claim 1, wherein the irradiation unit irradiates the plurality of beams obliquely with respect to a vertical direction from above. The object detection apparatus according to claim 1, wherein the object is a walking stick for a visually impaired person. Irradiating means for irradiating each of a plurality of individual regions within a predetermined monitoring region with a plurality of beams;
Light receiving means for receiving reflected light from a retroreflective material that is retroreflective material provided in advance on the object to be detected and retroreflects the beam;
Determining means for determining whether or not the retroreflective material is present in the monitoring region based on a signal from the light receiving means;
With
The object is a cane for the visually impaired,
The irradiation means irradiates two or more of the plurality of beams at different timings, as different modulation lights, or as different modulation lights at different timings,
The irradiating means divides the plurality of beams obliquely from above in the vertical direction so that the amount of light reflected by the retroreflecting material and received by the light receiving means changes according to the direction of the retroreflecting material. Irradiated,
The determination unit determines whether or not the retroreflective material is present in the monitoring region in a state of facing a predetermined direction.

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