JP5841498B2 - Object detection device - Google Patents

Description

  The present invention relates to an object detection device, and more particularly to an object detection device that emits mixed light having a plurality of wavelengths to a detection object.

  2. Description of the Related Art Conventionally, an apparatus that optically detects an object and determines attributes such as a material and a state thereof is known. For example, in Patent Document 1 below, a plurality of different short-wavelength infrared lights are irradiated toward the measurement space, and a normalized index is calculated from the reflectance of reflected light or the transmittance of transmitted light of each wavelength observed. Thus, there is disclosed an object identification device capable of detecting the type of an object existing in the measurement space based on the normalization index and a preset identification condition.

  Further, in an apparatus for optically detecting an object, it is extremely important that light of different wavelengths emitted from a plurality of light sources is uniformly irradiated onto the object. Non-Patent Document 1 below discloses a synthesis method using multi-core bifurcated fibers as a method of synthesizing illumination light having a plurality of wavelengths. According to this synthesis method, in a sensor system that detects human skin by irradiating LED light, LED light with different wavelengths is emitted using a plurality of fibers, and the light is synthesized by bundling these fibers. Mixed.

JP 2010-217149 A

APPLIED OPTICS / Vol.51, No.12 / 20 April 2012

  However, in the object identification device disclosed in Patent Document 1, in order to irradiate light with no unevenness between irradiation wavelengths with respect to an object existing in the distance, the irradiation angles of a plurality of illumination systems are accurately controlled. It is necessary to perform advanced irradiation adjustment techniques such as high-intensity light irradiation in order to reach far away. In particular, when tracking a moving object, it is necessary to instantaneously adjust the field axis of the sensor, the optical axes of a plurality of illumination lights, and the like, making it difficult to identify with high accuracy.

  Further, in the sensor system disclosed in Non-Patent Document 1, a plurality of fibers that emit LED light of different wavelengths are bundled, so that the axis of the observation system and the axis of the LED light are different, and are close to each other. Although it is possible to detect a certain object, it is not suitable for detecting a distant object. In order to detect a distant object, it is necessary to irradiate a powerful and uniformly mixed light. However, in the method of bundling this optical fiber, the intensity of incident light is made uniform and a large number of fibers are separated. It is difficult to detect distant objects because advanced adjustment work such as aggregation at equal density is required.

  Therefore, an object of the present invention is to provide an object detection apparatus that can uniformly irradiate a distant object with a plurality of illumination lights having different wavelengths.

  In order to solve the above-described problem, an object detection device of the present invention is provided with a plurality of light sources having different wavelengths, a scattering plate that reflects light emitted from the light source, and opposed to the scattering plate, A concave reflecting mirror for condensing the light emitted from the light source on the scattering plate, and light in the space formed by the scattering plate and the concave reflecting mirror is incident and radiates from the output end to the outside at a wide angle. A compound parabolic concentrator, a parabolic mirror that reflects light emitted from the output end as substantially parallel light, and coaxial with the axis of the substantially parallel light reflected by the parabolic mirror. And an observation sensor for observing light in which the parallel light is reflected by the object.

  In the object detection device of the present invention, it is preferable that an input end of the composite paraboloidal collector is disposed in a space formed by the scattering plate and the concave reflecting mirror.

  In the object detection device of the present invention, it is preferable that the light source is disposed on the concave reflecting mirror.

  In the object detection apparatus of the present invention, the light source is disposed on the scattering plate, and an auxiliary reflecting plate that guides light emitted from the light source to the scattering plate is formed by the scattering plate and the concave reflecting mirror. It is preferable that it is disposed in the formed space and at the periphery of the composite parabolic concentrator.

  In the object detection device of the present invention, it is preferable that the parabolic mirror and the observation sensor are arranged on the same axis.

  Further, the object detection apparatus of the present invention is a conical reflection that reflects light in a narrow angle direction emitted from the output end portion in a wide angle direction on the axis of the output end portion of the compound parabolic concentrator. It is preferable to further comprise a mirror.

  In the object detection device of the present invention, it is preferable that the light source, the scattering plate, and the concave reflecting mirror are arranged at positions that do not block substantially parallel light reflected from the parabolic mirror.

  In the object detection device of the present invention, the compound parabolic concentrator is inserted into an opening formed in the parabolic mirror, and the focal position of the parabolic mirror and the compound paraboloid A convex mirror is further disposed between the surface-type concentrators and facing the compound parabolic concentrator that reflects the light emitted from the output end to the parabolic mirror. Is preferred.

  According to the object detection device of the present invention, it is possible to efficiently irradiate an object existing on the same axis as the observation sensor in a state where a plurality of lights having different wavelengths are uniformly mixed, and the object is present at a distance. The target to be detected can be detected with high accuracy.

It is a schematic block diagram which shows 1st Embodiment of the target object detection apparatus which concerns on this invention. It is a functional block diagram of the target object identification apparatus provided with the target object detection apparatus of this invention. (A)-(d) is a figure which shows an example of the light emission pattern by a target object identification device, the light emission pattern in a photodiode, and the light reception pattern for every wavelength. (A)-(d) is a figure which shows an example of the waveform of the signal obtained by sample-holding the light reception signal extracted for every wavelength, and the waveform of the said signal after passing a band pass filter part. (A)-(d) is a figure which shows an example of the waveform of the reference signal used in order to perform a phase-synchronization detection with respect to the light reception signal for every wavelength, and the waveform of the light reception signal by which the phase-synchronization detection was carried out. It is a schematic block diagram which shows 2nd Embodiment of the target object detection apparatus which concerns on this invention. It is a schematic block diagram which shows 3rd Embodiment of the target object detection apparatus which concerns on this invention. It is a schematic block diagram which shows 4th Embodiment of the target object detection apparatus which concerns on this invention.

  Hereinafter, an example of an embodiment of an object detection device according to the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 shows a first embodiment of the object detection apparatus.
The object detection apparatus 10A according to the first embodiment includes LEDs 11a and 11b, which are examples of light sources, a scattering plate 12, a concave reflecting mirror 13, a compound parabolic concentrator 14, and a parabolic mirror. 15 and an observation sensor 16. The LEDs 11 a and 11 b, the scattering plate 12, the concave reflecting mirror 13, and the CPC 14 constitute a light emitting unit 23. In addition, the object detection apparatus 10A further includes a lighting control unit 18, a preamplifier 19, and the like, which will be described with reference to FIG.

  The LEDs 11a and 11b emit light having different wavelengths. In this embodiment, the LEDs 11a and 11b are arranged symmetrically about the same circumference of the concave reflecting mirror 13 (symmetric to the central axis L of the observation sensor 16 shown in the figure). For example, three LEDs 11a having a wavelength λ1 and three LEDs 11b having a wavelength λ2 are alternately arranged on the same circumference. Further, the LEDs 11 a and 11 b are arranged toward the closed space 17 formed by the scattering plate 12 and the concave reflecting mirror 13.

  The scattering plate 12 scatters and reflects the light emitted from the LEDs 11a and 11b and has a disk shape. The scattering plate 12 is preferably composed of a member having a sufficiently high reflectance with respect to the light of the LED. For example, the scattering plate 12 preferably has a Lambertian surface having the same reflection coefficient regardless of the observation angle of light. By performing Lambertian reflection by the scattering plate 12, the scattered light having different wavelengths λ1 and λ2 is uniformly mixed (synthesized) while maintaining the intensity balance between the wavelengths. The scattering plate 12 is preferably a white scattering plate that does not have a special absorption spectrum (no wavelength dependency).

  The concave reflecting mirror 13 mirror-reflects the light emitted from the LEDs 11a and 11b to the scattering plate 12. The concave reflecting mirror 13 is opposed to the scattering plate 12 and covers the scattering plate 12 in a dome shape. Yes. As a result, a closed space 17 is formed by the scattering plate 12 and the concave reflecting mirror 13. The light of λ1 and λ2 having different wavelengths emitted from the LEDs 11a and 11b is repeatedly reflected between the scattering plate 12 and the concave reflecting mirror 13 in the closed space 17, and the reflected light is scattered by the concave reflecting mirror 13. The light is gradually condensed in a region close to the central portion of 12 and mixed uniformly.

  A compound parabolic concentrator (hereinafter also referred to as CPC) 14 receives light (mixed light of wavelengths λ1 and λ2) reflected by the scattering plate 12 at its input end 14a (left end in the figure). ), And the condensed light is radiated at a wide angle from the output end portion 14b (right end portion in the figure). The CPC 14 is disposed on the central axis L of the object detection device 10A. The central axis L refers to the observation system optical axis of the object detection apparatus 10A. The CPC 14 has a wide allowable light receiving angle, and can receive light reflected by the scattering plate 12 at an allowable angle of ± 25 ° (θ1 = 25 ° in the drawing) with respect to the central axis L of the object detection device 10A. .

  The CPC 14 is attached to the concave reflecting mirror 12 facing the scattering plate 12, and in this embodiment, the input end portion 14 a is disposed in the closed space 17. The input end portion 14a of the CPC 14 projects into the scattering plate 12 so as to protrude in accordance with the condensing position of the concave reflecting mirror 13 on the scattering plate 12 so that the light reflected by the scattering plate 12 can be received efficiently. Closely arranged. That is, the position of the CPC 14 with respect to the scattering plate 12 is set so that the scattering plate 12 (portion where the central light is concentrated) is arranged in a range of ± 25 ° where the CPC 14 can receive light.

  Further, the output end portion 14 b of the CPC 14 is disposed outside the closed space 17. The output end 14b of the CPC 14 has a narrowed shape and constitutes a substantially point light source. The CPC 14 condenses the light in the closed space 17 with high efficiency by the input end 14a, takes out the light flux with increased energy density as a substantially point light source from the output end 14b, and parabolases from the point light source to a wide angle. Light is emitted toward the surface mirror 15. The CPC 14 can emit light from the output end portion 14b to a wide angle (θ2 = 60 ° in the figure) of about ± 60 ° with respect to the central axis L. The CPC 14 is arranged so that the position of the output end portion 14 b thereof substantially coincides with the position of the focal point of the parabolic mirror 15.

  The light that is reflected by the scattering plate 12 and does not enter the input end portion 14a of the CPC 14 is reflected by the concave reflecting mirror 13 toward the scattering plate 12, and the reflection of the scattering plate 12 is repeated by repeating such reflection. The light is collected in an area close to the central portion. As a result, the illuminance near the center of the scattering plate 12 is increased, and the strong mixed light is incident on the CPC 14. In addition, since the allowable light receiving angle of the CPC 14 is ± 25 °, the scattering plate 12 having a high reflectivity disposed so as to face the CPC 14 is at least in a region corresponding to the region of ± 25 ° that is the light receiving angle of the CPC 14. You may make it arrange | position partially.

  The parabolic mirror 15 projects light emitted from the output end 14 b of the CPC 14 and is disposed on the central axis L of the observation sensor 16 in the same manner as the CPC 14. As described above, the output end 14 b of the CPC 14 is disposed at the focal point of the parabolic mirror 15. Therefore, the light radiated from the output end 14b of the CPC 14 is symmetric with respect to the central axis L, and all the light is radiated from a position coincident with the focal position of the parabolic mirror 15, so that the parabolic mirror 15 Is reflected toward the object existing far from the optical axis of the observation sensor 16 (in the direction of arrow P in the figure) as substantially parallel light of the central axis L.

  The observation sensor 16 is a telephoto sensor that observes light reflected from an object, has a light receiving element (photodiode) and a telephoto lens, and is coaxial with substantially parallel light reflected by the parabolic mirror 15. Is arranged.

FIG. 2 is a functional block diagram of the object identification device 1 including the object detection device 10A according to the first embodiment.
The object identification device 1 intermittently lights a plurality of light sources having different wavelengths in a predetermined light emission pattern, detects reflected light with respect to light irradiated on the object, measures the reflectance, and calculates from the reflectance. The apparatus is capable of determining whether or not the object is human skin based on the index value, and includes an object detection device 10A and a detection processing device 30.

  As shown in FIGS. 1 and 2, the object detection device 10A includes LEDs 11a and 11b, a scattering plate 12, a concave reflecting mirror 13, a CPC 14, a parabolic mirror 15, an observation sensor (photodiode: PD). ) 16 and a preamplifier 19. As shown in FIG. 2, the detection processing device 30 includes a clock signal output unit 31, a phase synchronous detection unit 32, a frequency division / delay circuit unit 33, and an object calculation determination unit 34.

  The LEDs 11a and 11b are light sources that emit light having different wavelengths (λ1, λ2) by applying a voltage of a predetermined magnitude, and both emit light in the near infrared region in this embodiment. Specifically, the emission wavelength λ1 of the LED 11a is 1070 nm, and the emission wavelength λ2 of the LED 11b is 1550 nm. The reason why the emission wavelengths of the LEDs 11a and 11b are set to the above two wavelengths is that the identification target of the object identification device 1 is human skin. That is, the light of the 1070 nm band has a particularly high reflectance to human skin than other bands, and the light of the 1550 nm band has a particularly low reflectance to human skin than other bands. LEDs 11a and 11b having these two wavelengths as emission wavelengths are used. In addition, when the identification object of the target object identification apparatus 1 differs, LED of an appropriate light emission wavelength is used according to the identification object.

  Further, as described in FIG. 1, the object detection device 10A is provided with the same number of LEDs 11a and 11b, so that the amount of light when the LED 11a is turned on is equal to the amount of light when the LED 11b is turned on. In the object detection device 10A that is set, the LEDs 11a and LEDs 11b are alternately arranged symmetrically on the concave reflecting mirror 13, and the light distribution when the LEDs 11a are turned on and the LEDs 11b are turned on There is no difference in the light distribution.

  The lighting control unit 18 drives the LEDs 11 a and 11 b with a lighting / non-lighting pattern having a frequency corresponding to the clock signal input from the clock signal output unit 31 provided in the detection processing device 30. Specifically, the detection processing device 30 assumes that one clock width (unit period) of the clock signal input from the clock signal output unit 31 is a unit time width, as shown in FIG. The LEDs 11a and 11b are driven in a lighting / non-lighting pattern that is repeated at a period corresponding to 16 times the above.

  As shown in FIG. 3, in the lighting / non-lighting patterns numbered 1 to 32 for each unit time width, the repetition period is a time width from 1 to 16 and a time width from 17 to 32. . That is, in FIG. 3, the lighting / non-lighting pattern of the LEDs 11a and 11b is shown for two repetition periods (unit time width × 32). In the present embodiment, the frequency of the clock signal input from the clock signal output unit 31 is 16 kHz. Therefore, the unit time width is 62.5 μsec, and the repetition cycle of the lighting / non-lighting pattern of the LEDs 11a and 11b is 1000 μsec (repetition frequency is 1 kHz).

  The LED 11a is lit in the first, third, fourth, and sixth unit time widths in the time series order in the repetition cycle from No. 1 to No. 16 of the lighting / non-lighting pattern shown in FIG. , 7, 8, and 10th unit time width. That is, when either one of the LEDs 11a and 11b is lit, the other LED is lit in an exclusive pattern that is not lit. In addition, in the 2nd, 9th, and 11th-16th unit time width | variety in the repetition period to the 1st-16th of the lighting / non-lighting pattern shown to Fig.3 (a), neither LED11a, 11b lights.

  The observation sensor 16 outputs an electrical signal (light reception signal) having a magnitude corresponding to the light reception intensity of the incident light to the preamplifier 19. As shown in FIG. 3B, the signal received by the observation sensor 16 when the LEDs 11a and 11b are lit in the lighting / non-lighting pattern is a pattern (light receiving pattern) corresponding to the lighting / non-lighting pattern. ). The observation sensor 16 is an example of the observation sensor according to the present invention, and an appropriate type of photodiode or another type of light receiving element is used as the observation sensor according to the detection environment. The preamplifier 19 amplifies the signal level of the light reception signal from the observation sensor 16 and outputs the amplified light reception signal to the phase-synchronization detection unit 32 of the detection processing device 30.

  The phase-synchronous detection unit 32 includes extraction units 41 and 42, sample and hold units 43 and 44, bandpass filter units 45 and 46, and lock-in amplifier units 47 and 48. Among these, the extraction units 41 and 42, the sample and hold units 43 and 44, and the lock-in amplifier units 47 and 48 are driven based on the timing of the clock signal supplied from the clock signal output unit 31.

  The extraction units 41 and 42 are chopper circuits in the present embodiment, and sample the lighting / non-lighting pattern signals of the LEDs 11a and 11b from the light reception signals input from the observation sensor 16, and use the sampled signals. Output to the corresponding sample and hold units 43 and 44. For example, the extraction unit 41 extracts a light reception signal in the lighting period of the LED 11a from the light reception signals input from the observation sensor 16, and receives light in a period in which the phase is shifted by a half cycle with respect to the repetition period of the lighting period. The signal is extracted as a light reception signal in the non-lighting period.

  More specifically, the extraction unit 41 starts from the observation sensor 16 in the first, third, fourth, and sixth unit time widths when the LED 11a is lit in the time-series order in the repetition cycle of the lighting / non-lighting pattern. The output light reception signal is extracted as the light reception signal during the lighting period of the LED 11a, and the light reception output from the observation sensor 16 in the ninth, eleventh, twelfth, and fourteenth unit time widths when the LEDs 11a and 11b are not lit. The signal is extracted as a light reception signal in the non-lighting period (see FIG. 3C).

  Then, the extraction unit 41 uses the extracted light reception signal of each unit time width as a signal of a lighting / non-lighting pattern of the LED 11a (hereinafter, this signal is referred to as a “first extraction signal”). Output to. In this first extraction signal, as shown in FIG. 3C, the light reception signal when the LED 11a is turned on and the light reception signal when the LEDs 11a and 11b are not turned on have the same repetition period and have a phase corresponding to a half period. Contained as a different component.

  On the other hand, the extraction unit 42 extracts the light reception signal during the lighting period of the LED 11b from the light reception signals input from the observation sensor 16, and the phase is shifted by a half period with respect to the repetition period of the lighting period. The light reception signal in the period is extracted as the light reception signal in the non-lighting period. More specifically, the extraction unit 42 detects from the observation sensor 16 in the fifth, seventh, eighth, and tenth unit time widths when the LED 11b is lit in the time series order in the repetition cycle of the lighting / non-lighting pattern. The output light reception signal is extracted as the light reception signal during the lighting period of the LED 11b, and the light reception output from the observation sensor 16 in the second, thirteenth, fifteenth, and sixteenth unit time widths when neither of the LEDs 11a and 11b is lit. The signal is extracted as a light reception signal in the non-lighting period (see FIG. 3D).

  Then, the extraction unit 42 uses the extracted light reception signal of each unit time width as a signal of a lighting / non-lighting pattern of the LED 11b (hereinafter, this signal is referred to as a “second extraction signal”). Output to. In this second extraction signal, as shown in FIG. 3D, the light receiving signal when the LED 11b is turned on and the light receiving signal when the LEDs 11a and 11b are not turned on have the same repetition period and have a phase corresponding to a half period. Contained as a different component.

  The sample and hold units 43 and 44 are signals in which the first extracted signal and the second extracted signal input from the extracting units 41 and 42 are maintained at the previous signal level until the signal level for each unit time width changes. And output to the bandpass filter units 45 and 46. For example, the sample and hold unit 43 rises to the level of the light reception signal when the LED 11a is lit in the first unit time width in the repetition cycle of the first extraction signal (see FIG. 3C), and then the LED 11a The level is maintained until the ninth unit time width in which the light reception signal at the time of non-lighting exists, and from the ninth unit time width to the unit time width at which the light reception signal at the time of lighting of the LED 11a next exists. Maintains the level of the received light signal when lit.

  As a result, the sample and hold unit 43 converts the first extracted signal into a rectangular wave signal shown in FIG. 4A and outputs the signal to the bandpass filter unit 45. Similarly, the sample and hold unit 44 converts the second extracted signal into a rectangular wave signal shown in FIG. 4B and outputs it to the bandpass filter unit 46. Further, as shown in FIGS. 4A and 4B, the light receiving patterns that are the basis of the first extraction signal and the second extraction signal have the same repetition period and are each 1 / of the repetition period. It can be seen that the pattern has a phase difference corresponding to 4 (having orthogonal relation to each other).

  The bandpass filter units 45 and 46 turn on / off the LEDs 11a and 11b among the rectangular wave signals corresponding to the first and second extracted signals input from the sample and hold units 43 and 44, respectively. A frequency component corresponding to the frequency (repetition period) of the pattern is transmitted. That is, in the present embodiment, a component repeated at a period corresponding to 16 times the unit time width is transmitted, and the other components are blocked. As a result, the signals corresponding to the first extracted signal and the second extracted signal become signals having sine waveforms orthogonal to each other, as shown in FIGS. 4 (c) and 4 (d).

  These sine waves have a peak at the lighting timing of the LEDs 11a and 11b, and become the bottom at the sample timing when the LEDs 11a and 11b are not lit (when the background light is sampled). That is, the output signal from the bandpass filter unit 45 has a peak between the third and fourth unit time widths that are the lighting timing of the LED 11a, and the 11th and 12th sampling timings when the LED 11a is not lit. In the unit time width (see FIGS. 3C and 4C). Similarly, the output signal from the band-pass filter unit 46 has a peak between the seventh and eighth unit time widths that are the lighting timing of the LED 11b, and the 15th that is the sample timing when the LED 11b is not lit. And the 16th unit time width (see FIGS. 3D and 4D).

  The lock-in amplifiers 47 and 48 have the same frequency (repetition cycle) as the lighting / non-lighting patterns of the LEDs 11a and 11b with respect to the signals input from the bandpass filter units 45 and 46, and the LEDs 11a and 11b Phase synchronous detection is performed using a reference signal in which the lighting period and the peak phase are the same (or have a certain phase relationship). In this embodiment, the lock-in amplifiers 47 and 48 include a first reference signal obtained by dividing the clock signal output from the clock signal output unit 31 by 16 by the frequency division / delay circuit unit 33 (FIG. 5A). And a second reference signal obtained by dividing the clock signal by 16 by the frequency divider / delay circuit unit 33 and delaying it by 1/4 of the repetition cycle of the lighting / non-lighting pattern (see FIG. 5B). Are entered.

  The lock-in amplifier 47 performs phase-locked detection on the signal input from the band-pass filter 45 with the first reference signal. Further, the lock-in amplifier unit 48 performs phase-locked detection on the signal input from the bandpass filter unit 46 with the second reference signal. Here, as shown in FIGS. 3C and 3D, since the phases of the lighting timing of the LEDs 11a and 11b and the non-lighting sample timing (at the time of background light sampling) are different, the lock-in amplifier unit 47, By performing the phase-synchronized detection at 48, the background light components included in the signals from the bandpass filter units 45 and 46 are removed.

  As a result, only the signal component having the peak received light intensity remains at the lighting timing of the LEDs 11a and 11b (see FIGS. 5C and 5D). Then, the phase-locked signal is converted into a DC component signal using a low-pass filter or a sample-and-hold circuit (not shown) and output to the object calculation determination unit 34. That is, the lock-in amplifier units 47 and 48 output a signal indicating the intensity level of the reflected light with respect to the irradiation light of each of the LEDs 11 a and 11 b to the object calculation determination unit 34.

  The object calculation determination unit 34 includes an index calculation unit 51 and an attribute determination unit 52. Based on the signals input from the lock-in amplifiers 47 and 48, the index calculation unit 51 reflects the reflectance (in the object) of the irradiation light (1070 nm band) from the LED 11a and the irradiation light (1550 nm band) from the LED 11b. Is calculated. In the present embodiment, a clock signal is input from the clock signal output unit 31 to the index calculation unit 51, and the index calculation unit 51 is input from the lock-in amplifier units 47 and 48 for each cycle of the clock signal. Based on the synchronous component in the signal, the reflectance of each light is calculated.

  Then, the index calculation unit 51 calculates a normalized index (Normalized Difference Human Index: NDHI) represented by the following formula based on the calculated reflectance of each light, and outputs it to the attribute determination unit 52.

NDHI = (R1070−R1550) / (R1070 + R1550)
R1070: Reflectance of the irradiation light (1070 nm band) from the LED 11a R1550: Reflectance of the irradiation light (1550 nm band) from the LED 11b

  Based on the normalized index calculated by the index calculation unit 51 and preset determination conditions, the attribute determination unit 52 has human skin in the region irradiated with the light of the two wavelengths from the object detection device 10A. It is determined whether or not. In the present embodiment, the attribute determination unit 52 determines that human skin is present in the irradiation region when the normalization index exceeds 0.7, for example, and if it is 0.5 or less, there is no human skin. Judge that it is. The determination conditions are not limited to the present embodiment, and are preferably set to optimum conditions according to the detection environment.

  In this way, the object identification device 1 irradiates light with an infrared wavelength that is effective for human skin identification, and calculates the normalization index from the reflectance so that the human skin is within the irradiation region. It can be easily determined whether or not it exists. Further, when detecting the reflected light, the object identification device 1 receives the light detected in the lighting period and the non-lighting period of the light source in different phases and applies phase-synchronized detection to detect the background from the reflected light. Light can be removed accurately and simply.

  According to the object detection apparatus 10A having the above-described configuration, the light emitted from the plurality of LEDs 11a and 11b having different wavelengths is irradiated onto the scattering plate 12 facing the concave reflecting mirror 13, and the light is concave. By reflecting between the reflecting mirror 13 and the scattering plate 12 and reciprocating a number of times, it is possible to uniformly mix and converge light of a plurality of wavelengths on the scattering plate 12. Then, the mixed light emitted from the scattering plate 12 is applied to the CPC 14 disposed close to the scattering plate 12 so as to face the scattering plate 12, and a light beam with an increased energy density can be emitted from the output end portion 14b of the CPC 14 at a wide angle. Further, the radiated light is converted into parallel light coaxial with the observation sensor 16 by the parabolic mirror 15, irradiated to the object as inspection light, and the reflected light from the object is observed by the observation sensor 16. Can do. In this way, it is possible to irradiate the object existing far away with uniform inspection light while matching the inspection light and the range of observation, and to detect the object existing far away with high accuracy. .

  Further, since the input end portion 14 of the CPC 14 is disposed in the closed space 17 formed by the scattering plate 12 and the concave reflecting mirror 13, the mixed light reflected by the scattering plate 12 can be efficiently collected.

  Further, by arranging the parabolic mirror 15 and the observation sensor 16 on the same axis, the object detection device 10A can be reduced in size.

  Further, since the LEDs 11a and 11b are arranged at intervals on the same circumference of the concave reflecting mirror 13, it is possible to suppress a temperature rise and use a high output intensity. It is possible to detect a distant object with high accuracy.

  Further, by adjusting the diameter of the parabolic mirror 15 by, for example, increasing the diameter of the parabolic mirror 15, the irradiation distance, irradiation range, irradiation intensity, etc. of the inspection light applied to the object can be easily adjusted. it can.

(Second Embodiment)
FIG. 6 shows a second embodiment of the object detection apparatus.
The object detection device 10B according to the second embodiment has the point that the LEDs 11a and 11b are installed on the scattering plate 12, the point that the auxiliary reflecting plate 21 is provided in the closed space 17, and the output end of the CPC 14. Unlike the object detection apparatus 10A according to the first embodiment in that the conical reflecting mirror 22 is provided on the central axis L of 14b, the LEDs 11a and 11b, the scattering plate 12, the concave reflecting mirror 13, and the CPC 14 The auxiliary reflector 21 constitutes a light emitting part 23a. Hereinafter, although the second embodiment will be described, the same or similar parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

  In the object detection device 10B, the scattering plate 12 on which the LEDs 11a and 11b are installed is configured by using a metal plate having a disk shape as a base member and providing a scattering plate on one surface of the central portion of the metal disk. Yes. The scattering plate may be provided in a region that has a sufficiently high reflectance with respect to the light of the LED and can correspond to at least the allowable light receiving angle of the CPC 14.

  The LEDs 11a and 11b are alternately arranged in a plurality of positions with axial symmetry (center axis L shown in the figure) at positions avoiding the area of the scattering plate on the metal disk. The LEDs 11a and 11b are arranged toward the closed space 17 through through holes formed in a metal disk. Since the metal disk also serves as a heat radiating member, a large LED can be installed, and the intensity of the output light can be increased to detect a distant object with high accuracy.

  The LEDs 11a and 11b may be disposed in the closed space 17 through a through hole formed in the disc-shaped scattering plate 12. With this configuration, light of a plurality of wavelengths can be uniformly mixed and converged in the closed space 17 more efficiently.

  The auxiliary reflecting plate 21 is a reflecting plate for effectively guiding the projection light to the scattering plate 12, and has an annular shape having a hole through which the CPC 14 penetrates at the center thereof. The auxiliary reflecting plate 21 is provided in the closed space 17, that is, on the concave surface side of the concave reflecting mirror 13, and is disposed so as to face the scattering plate 12 and cover the periphery of the CPC 14. By arranging the auxiliary reflector 21 in the peripheral part of the CPC 14 in this way, the light emitted from the LEDs 11a and 11b and not incident on the CPC 14 is effectively guided to the scattering plate 12 and efficiently targeted without loss. It can be used as inspection light for objects.

  The conical reflecting mirror 22 is a reflecting mirror for changing the direction of light emitted from the output end portion 14b of the CPC 14, and is coaxial with the central axis L where the CPC 14 is disposed and is the output end portion 14b of the CPC 14. Is provided. The conical reflecting mirror 22 has a conical shape, and is arranged in a state where the conical portion is directed to the output end portion 14 b of the CPC 14.

  When the conical reflecting mirror 22 is not disposed, the light near the center (near the central axis L) among the light emitted from the CPC 14 and reflected by the parabolic mirror 15 is blocked by the observation sensor 16 or the concave reflecting mirror 13. Therefore, it cannot be effectively used as inspection light for the object. Therefore, by arranging the conical reflecting mirror 22, the light emitted from the output end portion 14b of the CPC 14 in the direction with a small opening angle (the narrow angle direction) is reflected by the conical reflecting mirror 22, and the peripheral portion of the parabolic mirror 15 is reflected. Guide to (wide angle direction). Thereby, it is possible to prevent the occurrence of energy loss due to blocking of the observation sensor 16 with respect to the light reflected by the parabolic mirror 15, and efficiently irradiate the object with the light emitted from the CPC 14 as the inspection light. be able to. Note that the conical reflecting mirror 22 has the same function and effect when used in the object detection apparatus 10A according to the first embodiment described above.

(Third embodiment)
FIG. 7 shows a third embodiment of the object detection apparatus.
In the object detection device 10C according to the third embodiment, the parabolic mirror that reflects the light emitted from the CPC 14 and irradiates the object toward the object is not arranged coaxially with the central axis L of the observation sensor 16. The object detection device 10A according to the first embodiment is different from the object detection device 10A according to the first embodiment in that it is replaced with an axial parabolic mirror 15. Hereinafter, the third embodiment will be described. The same or similar parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

  By disposing the non-axial parabolic mirror 15 at a position shifted from the central axis L, the light emitting portion 23b composed of the LEDs 11a and 11b, the scattering plate 12, the concave reflecting mirror 13, and the CPC 14 is shown in the figure. As shown, it can be arranged at a position separated from the central axis L.

  In this case, the light radiated from the CPC 14 is reflected by the non-axial parabolic mirror 15 and is substantially parallel to the observation sensor 16 arranged on the central axis L in the coaxial direction (the direction of the arrow P in the figure). Irradiated. Therefore, the light reflected by the non-axis parabolic mirror 15 (substantially parallel light) is not blocked by the light emitting part 23b and no energy loss occurs. For this reason, the light radiated | emitted from CPC14 is efficiently irradiated also to a far object.

  In the third embodiment, the auxiliary reflector 21 may be provided in the closed space 17 as in the second embodiment. In the third embodiment, the LEDs 11a and 11b may be provided on the concave reflecting mirror 13 as in the first embodiment.

(Fourth embodiment)
FIG. 8 shows a fourth embodiment of the object detection apparatus.
The object detection device 10D according to the fourth embodiment includes an LED 11a, 11b, a scattering plate 12, a concave reflecting mirror 13, and a light emitting unit 23 including a CPC 14 outside the parabolic mirror 15 (back side). Is different from the object detection apparatus 10A according to the first embodiment in that the convex reflecting mirror 24 is disposed in front of the parabolic mirror 15 on the optical axis. Hereinafter, the fourth embodiment will be described. The same or similar parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

  In the object detection device 10D, the convex reflecting mirror 24 is opposed to the front on the central axis L of the observation sensor 16, and the light of the CPC 14 is emitted from the opening formed in the center of the parabolic mirror 15 (on the central axis L). A so-called Cassegrain method is used in which the light is reflected by the convex reflecting mirror 24 and the reflected light is irradiated onto the parabolic mirror 15.

  More specifically, the light emitting unit 23 is disposed on the back side (right side in the drawing) of the parabolic mirror 15, and the light emitting unit is formed in an opening formed in the central portion (on the central axis L) of the parabolic mirror 15. The output end portion 14b of the 23 CPCs 14 is inserted in the central axis L direction. A convex reflecting mirror 24 having a convex shape toward the CPC 14 is disposed between the position of the focal point F of the parabolic mirror 15 and the output end portion 14b of the CPC 14. The light emitted from the CPC 14 is reflected by the convex reflecting mirror 24 and then irradiated to the parabolic mirror 15. The irradiated light is reflected by the parabolic mirror 15 and irradiated as substantially parallel light in the direction coaxial with the observation sensor 16 arranged on the central axis L (in the direction of arrow P in the figure).

  With this configuration, the light emitting unit 23 is not disposed on the optical axis of the substantially parallel light reflected by the parabolic mirror 15, so that no energy loss occurs due to the blocking of the light emitting unit 23. For this reason, the light radiated from the CPC 14 is efficiently reflected and reaches a distant object, thereby enabling highly accurate detection.

  L: central axis, 10A, 10B, 10C, 10D: object detection device, 11a, 11b: LED (an example of a light source), 12: scattering plate, 13: concave reflector, 14: compound parabolic concentrator (CPC), 15: parabolic mirror, 16: observation sensor, 17: closed space, 21: auxiliary reflector, 22: conical reflector, 23, 23a, 23b: light emitting part, 24: convex reflector

Claims (8)

A plurality of light sources having different wavelengths;
A scattering plate that reflects light emitted from the light source;
A concave reflecting mirror disposed opposite to the scattering plate and condensing the light emitted from the light source on the scattering plate;
A compound parabolic concentrator that receives light in a space formed by the scattering plate and the concave reflecting mirror and emits a wide angle from the output end to the outside of the space;
A parabolic mirror that reflects light emitted from the output end as substantially parallel light;
An observation sensor that is arranged coaxially with an axis of substantially parallel light reflected by the parabolic mirror, and that observes the light reflected by the object;
An object detection apparatus comprising:   2. The object detection device according to claim 1, wherein an input end of the composite parabolic concentrator is disposed in a space formed by the scattering plate and the concave reflecting mirror.   The object detection apparatus according to claim 1, wherein the light source is disposed on the concave reflecting mirror. The light source is disposed on the scattering plate;
An auxiliary reflector that guides light emitted from the light source to the scattering plate is in a space formed by the scattering plate and the concave reflecting mirror, and is disposed in the periphery of the composite parabolic concentrator The object detection device according to claim 1, wherein the object detection device is an object detection device.   5. The object detection device according to claim 1, wherein the parabolic mirror and the observation sensor are arranged on the same axis. 6.   The conical reflector for reflecting narrow-angle light emitted from the output end in the wide-angle direction is further provided on the axis of the output end of the compound parabolic concentrator. The target object detection apparatus as described in any one of 1 to 5.   The said light source, a scattering plate, and a concave reflective mirror are arrange | positioned in the position which does not interrupt | block the substantially parallel light reflected from the said parabolic mirror, It is any one of Claim 1 to 4 characterized by the above-mentioned. Object detection device. The composite parabolic concentrator is inserted through an opening formed in the parabolic mirror,
The composite paraboloidal collector is disposed between the focal point of the parabolic mirror and the composite parabolic concentrator, and reflects light emitted from the output end to the parabolic mirror. The object detection apparatus according to claim 7, further comprising a reflecting mirror convex toward the optical device.

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