JP2010107448A - Distance measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distance measuring device capable of detecting a distant object, and simultaneously detecting a near object with high resolution. <P>SOLUTION: This distance measuring device includes: a light emitting means including a first light wave application means for emitting a first light wave having a first wavelength band toward another object by being flashed at a first flashing period, and a second light wave application means for emitting a second light wave having a second wavelength band toward another object by being flashed at a second flashing period; a spectral transmission means including a first light filtering means for allowing transmission of only light having the first wavelength band, and a second light filtering means for allowing transmission of only light having the second wavelength band; a photosensitive means including a first light receiving means for receiving first transmission light reflected by an object and transmitted through the first light filtering means and outputting a first light reception signal corresponding to a reception amount of the first transmission light, and a second light receiving means for receiving second transmission light reflected by the object and transmitted through the second light filtering means and outputting a second light reception signal corresponding to a reception amount of the second transmission light; and a distance calculation means for calculating a distance to the object based on the first light reception signal and the second light reception signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a distance measuring device, and more particularly to a distance measuring device using light waves or sound waves.

  2. Description of the Related Art Conventionally, a distance measuring device has been developed that emits a wave such as a light wave or an ultrasonic wave toward a measurement target, receives a reflected wave that is reflected by the measurement target, and calculates a distance to the measurement target. In general, the distance measuring device calculates the distance to the measurement object based on the time required from the radiation of the wave to the reflected wave, that is, the round-trip time of the wave.

A distance measuring apparatus as described above is disclosed in, for example, Patent Document 1. The optical distance measuring device disclosed in Patent Document 1 includes a light emitting element and two storage elements. The storage elements each store charges corresponding to the amount of received light. The optical distance measuring device transmits a light wave signal by causing the light emitting element to emit light in synchronization with a pulse signal having a predetermined period. The optical distance measuring device receives the reflected wave of the light wave signal reflected by the measurement object at a predetermined timing, and accumulates charges in each of the two storage elements. The optical distance measuring device calculates a differential signal based on the difference between the charge signals stored in the respective storage elements, and calculates a distance to the measurement object based on the differential signal. Here, the differential signal is a signal from which noise such as background light has been removed by the process of calculating the difference between the charge signals. Therefore, the optical distance measuring device can calculate the round-trip time until the light wave is reflected back to the measurement object and returns, and therefore the distance to the measurement object can be calculated.
JP 2007-132848 A

  For example, when the vehicle has a distance measuring device as described above and measures the approach distance between the vehicle and an object around the vehicle, the distance measuring device includes an object such as another vehicle approaching the vehicle as much as possible. It is required to be able to detect from a distance and to detect the distance to the object with a relatively high distance resolution for an object such as a pedestrian or a bicycle moving in the vicinity of the vehicle.

  And in order to measure the distance to the object located farther by the distance measuring device, it is necessary to make the light wave signal reach farther, and therefore, it is necessary to increase the intensity of the light wave signal. . In order to increase the intensity of the light wave signal, it is generally necessary to increase the time during which the light wave is continuously emitted, that is, the pulse width of the pulse signal.

  However, in the distance measuring apparatus as described above, when the pulse width of the pulse signal is increased, for example, when measuring the distance to the measurement object present at a relatively close position, the distance resolution is lowered. The distance resolution of the distance measuring apparatus as described above is determined by the length of a continuous wave train of the light wave emitted in synchronization with the pulse width of the pulse signal (hereinafter referred to as a wave train length). This is because if the interval in the direction of travel of the light wave between two different measurement objects is 1/2 or less of the wave train length, the reflected waves from the two measurement objects cannot be distinguished from each other. This is because the distance to the two measurement objects cannot be distinguished and detected. Therefore, as described above, if the pulse width is increased in order to measure the distance to an object located further away, the wave train length of the light wave becomes longer, and the distance resolution decreases when measuring a short distance. It will end up.

  As described above, in the conventional distance measuring device, it is difficult to achieve both the maximum measurable distance and the high distance resolution. The present invention has been made in view of the above problems, and an object of the present invention is to provide a distance measuring device capable of detecting a distant object and simultaneously detecting a nearby object with high resolution. .

  In order to solve the above problems, the present application adopts the following configuration. That is, the first invention is a first light wave irradiating means that blinks at a predetermined first blinking period and emits a first light wave in the first wavelength band toward another object, and the first blinking period. A light emitting means including at least a second light wave irradiating means for emitting a second light wave of a second wavelength band different from the first wavelength band toward another object by blinking at a different second blinking period; A spectral filtering means including at least a first filtering means for transmitting only light in the band and a second filtering means for transmitting only light in the second wavelength band; and a first filtering means reflected by an object. A first light receiving means for receiving the transmitted first transmitted light and outputting a first received light signal corresponding to the amount of the first transmitted light; and a second transmitted light reflected by the object and transmitted through the second filtering means. And a second light receiving means for outputting a second light receiving signal corresponding to the amount of received light of the second transmitted light. A photosensitive means including, and a distance calculating means for calculating the distance to the object based on the first light receiving signal and the second light receiving signal, a distance measuring device.

  According to a second aspect, in the first aspect, the first blinking period is set longer than the second blinking period, and the area through which the first filtering means transmits the first transmitted light is the second filtering means is the first filtering period. 2 It is set larger than the area through which transmitted light is transmitted.

  In a third aspect based on the second aspect, the first light receiving means has a light receiving surface having a predetermined unit area corresponding to the number of areas in which the first filtering means transmits the first transmitted light. The second light receiving means is configured by arranging the light receiving elements in the number corresponding to the area through which the second filtering means transmits the second transmitted light.

  In a fourth aspect based on the first aspect, the first blinking period is set longer than the second blinking period, and the first light receiving means is set to a light receiving sensitivity higher than the light receiving sensitivity set in the second light receiving means. Is done.

  In a fifth aspect based on the first aspect, the first filtering means is a first plate member that transmits only light in the first wavelength band, and the second filtering means is light in the second wavelength band. It is the 2nd plate-shaped member which permeate | transmits only.

  In a sixth aspect based on the fifth aspect, the spectral transmission means arranges the first and second filtering means by arranging the first plate-like member and the second plate-like member in a lattice shape, respectively. The photosensitive means is a single camera provided with a plurality of light receiving elements. The light receiving element that receives light transmitted through the first plate-like member is the first light-receiving means, and the second plate-like member is The light receiving elements that receive the transmitted light are respectively configured as second light receiving means.

  In a seventh aspect based on the sixth aspect, the number of the first plate-like members arranged in a grid is larger than the number of the second plate-like members arranged.

  In an eighth aspect based on the fifth aspect, the photosensitive means uses the first camera that receives light transmitted through the first plate member as the first light receiving means, and receives light transmitted through the second plate member. The second camera is configured as each of the second light receiving means, and the spectral transmission means uses the first plate-like member attached to the first camera as the first filtering means, and the second plate-like attached to the second camera. Each member is configured as the second filtering means.

  In a ninth aspect based on the first aspect, the light emitting means is mounted in the vicinity of the headlamp of the vehicle, the first light wave irradiation means emits the first light wave toward the periphery of the vehicle, and the second light wave irradiation means is the vehicle. The second light wave is emitted toward the periphery of the vehicle, the photosensitive means is mounted on the front grille of the vehicle, and the distance calculating means calculates the distance to an object existing around the vehicle.

  In a tenth aspect based on the first aspect, the first blinking cycle is set longer than the second blinking cycle, and the light emitting means is a third blinking shorter than the first blinking cycle and longer than the second blinking cycle. The third filtered light further includes third light wave irradiating means that blinks periodically and emits the third light wave of the third wavelength band toward another object, and the spectral transmission means transmits only the light of the third wavelength band. And a photosensitive unit that receives the third transmitted light reflected by the object and transmitted through the third filtering unit, and outputs a third received light signal corresponding to the amount of received light of the third transmitted light. And a distance calculating unit that calculates a distance to the object based on the first light receiving signal, the second light receiving signal, and the third light receiving signal.

  In an eleventh aspect of the invention, there is provided a first sound wave radiating means for intermittently radiating a first sound wave in the first frequency band toward another object at a predetermined first generation period, and a second different from the first frequency band. A sound wave generating means including at least a second sound wave emitting means for intermittently emitting a second sound wave in a frequency band at a second generation period different from the first generation period, and the first sound wave and the second sound wave are reflected by the object The first receiving means for receiving only the reverberation sound in the first frequency band from the reverberation sound and outputting the first reception signal corresponding to the received amount, and only the reverberation sound in the second frequency band from the reverberation sound Sound receiving means including at least a second receiving means for receiving and outputting a second received signal corresponding to the received amount, and a first distance calculating means for calculating a distance to the object based on the first received signal And a second distance for calculating the distance to the object based on the second received signal And detecting means, and a distance calculating means comprising at least a distance measuring device.

  According to the first invention, for example, the distance to the object relatively close to the distance measuring device is calculated based on the light wave having a relatively short wavelength, and at the same time, the distance from the distance measuring device to the relatively distant object is calculated. The distance can be calculated based on a relatively long wavelength light wave. Therefore, it is possible to detect relatively distant objects and simultaneously detect nearby objects with high resolution.

  According to the second invention, it is possible to improve the sensitivity of reflected light that reaches a relatively far object and has a long propagation path. Since reflected light with a long propagation path is easily attenuated, the intensity of an output signal obtained by receiving the reflected light is likely to decrease. However, even if the reflected light is attenuated by improving the sensitivity of the reflected light, A large output signal intensity can be obtained. When the output signal strength is weak, for example, the signal may be excluded as noise and an accurate distance may not be measured. However, the distance measuring device according to the second invention has a large signal strength as described above. As a result, the distance can be measured accurately.

  According to the third aspect of the invention, the sensitivity can be changed easily only by changing the number of parts and at a reduced manufacturing cost.

  According to the fourth invention, it is possible to easily change the sensitivity of the receiving element without rearranging the components.

  According to the fifth aspect, only the reflected light having a specific wavelength can be easily dispersed.

  According to the sixth aspect of the invention, for example, when attaching the housing to the vehicle, the attachment work is easy.

  According to the seventh invention, the sensitivity of the light in the corresponding wavelength band can be easily changed by changing the ratio of the number of the first plate member and the second plate member arranged in a lattice shape. it can.

  According to the eighth aspect, since the first housing and the second housing can be attached to different positions, for example, when each housing is attached to the vehicle, the degree of freedom in the layout of the attachment space Increase.

  According to the ninth aspect, the position of a distant object approaching the periphery of the vehicle can be detected, and at the same time, an object near the vehicle can be detected with high resolution.

  According to the tenth aspect of the invention, for example, the distance to the object existing at a long distance relative to the distance measuring device is calculated based on the light wave of the first wavelength, and at the same time, the distance measuring device is set to the medium distance relatively. Calculating the distance to the existing object based on the light wave of the third wavelength, and simultaneously calculating the distance to the object existing relatively close to the distance measuring device based on the light wave of the second wavelength. it can. Therefore, an object can be detected with a resolution corresponding to the detection distance.

  According to the eleventh aspect, the same effect as in the first aspect can be obtained using sound waves. Further, it is possible to realize a distance measuring device with a wide viewing angle at low cost as compared with the case where laser light is used.

(First embodiment)
Hereinafter, the distance measuring device 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 9.

  First, the functional configuration of the distance measuring device 1 will be described with reference to FIG. FIG. 1 is a block diagram showing a functional configuration of the distance measuring apparatus 1. As shown in FIG. 1, the distance measuring device 1 includes a pulse signal generator 11, a light emitter 12, a light receiver 13, a filter member 14, and a distance calculator 15. The light emitter 12 includes a first light emitting element 121 and a second light emitting element 122 that emit light waves having different wavelength bands. Hereinafter, the first light emitting element 121 and the second light emitting element 122 are collectively referred to as a light emitting element. The light receiver 13 includes a plurality of first light receiving elements 131, second light receiving elements 132, third light receiving elements 133, and fourth light receiving elements 134. Hereinafter, the first light receiving element 131, the second light receiving element 132, the third light receiving element 133, and the fourth light receiving element 134 are collectively referred to as a light receiving element. In addition, said apparatus which comprises the said distance measurement apparatus 1 shall operate | move while the distance measurement apparatus 1 is supplied with a power supply.

  The pulse signal generator 11 is a pulse signal generator that outputs a plurality of pulse signals having different periods and phases. The pulse signal generator 11 is typically a microcomputer having a plurality of signal output terminals.

  The pulse signal generation unit 11 is electrically connected to each light emitting element included in the light emitter 12 and each light receiving element included in the light receiver 13, and outputs pulse signals having different periods and phases to each light emitting element and each light receiving element. Output. A signal output from the pulse signal generator 11 to the first light emitting element 121 is referred to as a first light emitting element light emission signal. A signal output from the pulse signal generator 11 to the second light emitting element 122 is referred to as a second light emitting element light emission signal. A signal output from the pulse signal generator 11 to the first light receiving element is referred to as a first light receiving element shutter opening signal. A signal output from the pulse signal generator 11 to the second light receiving element is referred to as a second light receiving element shutter opening signal. A signal output from the pulse signal generator 11 to the third light receiving element is referred to as a third light receiving element shutter release signal. A signal output from the pulse signal generator 11 to the fourth light receiving element is referred to as a fourth light receiving element shutter opening signal.

  In the present embodiment, an example in which the pulse signal generation unit 11 is configured by a microcomputer will be described. However, the pulse signal generation unit 11 may have other hardware as long as it can output a plurality of pulse signals having different periods and phases. You may comprise by. For example, the pulse signal generator 11 may be configured by a clock device that outputs a predetermined pulse signal, and a modulation circuit that divides and modulates the pulse signal output from the clock device.

  The light emitter 12 is a light emitting device that emits two light waves of different wavelength bands. As described above, the light emitter 12 includes the first light emitting element 121 and the second light emitting element 122. The first light emitting element 121 and the second light emitting element 122 are typically light emitting elements such as laser diodes and LEDs (Light Emitting Diodes). The first light emitting element 121 radiates the light wave signal L1 in the wavelength band λ1 to the outside, and the second light emitting element 122 radiates the light wave signal L2 in the wavelength band λ2 to the outside. The first light emitting element 121 emits the light wave signal L1 at a timing according to the first light emitting element light emission signal output from the pulse signal generation unit 11. Further, the second light emitting element 122 emits the light wave signal L2 at a timing according to the second light emitting element light emission signal output from the pulse signal generation unit 11.

  The light receiver 13 is a light receiving device that receives a light wave signal emitted from the light emitter 12 and reflected by an object. As described above, the light receiver 13 includes the first light receiving element 131, the second light receiving element 132, the third light receiving element 133, and the fourth light receiving element 134. Each light receiving element is typically an element such as a photodiode having an electronic shutter function. Each light receiving element is arranged in a single casing 135 in a lattice shape with the light receiving surfaces facing in the same direction so as to constitute the receiving surface F of the light receiver 13 (see FIG. 2). In addition, if the image sensor of a digital camera is used for each pixel as the light receiving element, the light receiver 13 can be configured with one digital camera.

  Each light receiving element accumulates electric charge according to the amount of received light while the electronic shutter is open. Each light receiving element outputs a signal corresponding to the accumulated charge amount to the distance calculation unit 15 when the electronic shutter changes from the open state to the closed state, and does not accumulate charges while the electronic shutter is in the closed state. . Each light receiving element is electrically connected to the pulse signal generator 11 and switches the open / close state of the electronic shutter at different timings according to a signal input from the pulse signal generator 11. Specifically, the first light receiving element 131 switches the open / close state of the electronic shutter in accordance with the first light receiving element shutter opening signal. The second light receiving element 132 switches the open / close state of the electronic shutter according to the second light receiving element shutter opening signal. The third light receiving element 133 switches the open / close state of the electronic shutter according to the third light receiving element shutter opening signal. The fourth light receiving element 134 switches the open / close state of the electronic shutter according to the fourth light receiving element shutter opening signal.

  The filter member 14 is a plate-like member. Hereinafter, the filter member 14 will be described with reference to FIG. FIG. 2 is an example of a diagram illustrating how the filter member 14 is attached to the light receiver 13. The filter member 14 is attached so as to cover the receiving surface F of the light receiver 13 as shown in FIG. The filter member 14 is divided into grid-like sections so as to overlap with the light-receiving surfaces of the respective light-receiving elements arranged in a grid in the light receiver 13. Each section includes a first wavelength plate 141 (shaded portion in FIG. 2) that transmits a light wave in the wavelength band λ1 or a second wavelength plate 142 that transmits a light wave in the wavelength band λ2. Hereinafter, the first wave plate 141 and the second wave plate 142 are collectively referred to as a wave plate. FIG. 2 shows an example in which the first wave plate 141 and the second wave plate 142 are alternately arranged in a lattice shape. With the above configuration, the filter member 14 transmits only the light wave of the wavelength band λ1 or the light wave of the wavelength band λ2 for each of the sections.

  Here, on the receiving surface F, the first light receiving element 131 and the second light receiving element 132 are arranged in a region F1 (filled portion in FIG. 2) overlapping the first wave plate 141. With such a configuration, the first light receiving element 131 and the second light receiving element 132 receive only the light wave of the wavelength band λ1 that passes through the first wave plate 141. Here, the first light receiving element 131 and the second light receiving element 132 are elements having the same light receiving sensitivity characteristic. In addition, it is assumed that the number of the first light receiving elements 131 and the second light receiving elements 132 arranged in the region F1 is the same. On the other hand, the third light receiving element 133 and the fourth light receiving element 134 are disposed on the receiving surface F in a region F <b> 2 that overlaps with the second wavelength plate 142. With such a configuration, the third light receiving element 133 and the fourth light receiving element 134 receive only light waves in the wavelength band λ <b> 2 that pass through the second wave plate 142. Here, the third light receiving element 133 and the fourth light receiving element 134 are elements having the same light receiving sensitivity characteristic. In addition, the number of the third light receiving elements 133 and the fourth light receiving elements 134 arranged in the region F2 is the same.

  Returning to the description of FIG. 1, the distance calculation unit 15 is typically a microcomputer including a processing device such as a CPU, a storage device such as a memory, and an interface circuit. The distance calculation unit 15 calculates the distance to the detected object based on the signal output from each photosensitive element, and outputs the measurement result.

  Next, referring to FIG. 3, how each light emitting element and each light receiving element operate in accordance with a signal output from the pulse signal generator 11 will be described. FIG. 3 is an example of a timing chart showing the operation of each of the light emitting element and the light receiving element.

  The (A) first light emitting element light emission signal in FIG. 3 indicates the first light emitting element light emission signal output from the pulse signal generator 11. As shown in (A) First light emitting element light emission signal in FIG. 3, the first light emitting element light emission signal is a signal in which a pulse having a pulse width Wa is repeated with a period of 2 Wa. The first light emitting element 121 emits the light wave signal L1 while receiving the pulse in synchronization with the pulse of the first light emitting element light emission signal.

  Here, it is assumed that the detected object 51 (see FIG. 1) that has radiated the light wave signal L1 reflects the light wave signal L1, and the reflected light Lr1 enters the light receiver 13. In FIG. 3, (B) the reflected light Lr1 in the wavelength band λ1 is a diagram showing the reflected light Lr1 in the wavelength band λ1 reaching the light receiver 13. In the following, as shown in (B) reflected light Lr1 in the wavelength band λ1 in FIG. 3, the delay time τa from the time when the emission of the light wave signal L1 is started (that is, when the pulse of the first light emitting element light emission signal rises). An example in which the reflected light Lr1 reaches the light receiver 13 after elapses will be described. Note that the value of the delay time τa is smaller than the pulse width Wa.

  As shown in (C) first light receiving element shutter opening signal in FIG. 3, the first light receiving element shutter opening signal output from the pulse signal generator 11 is the same as (A) first light emitting element light emitting signal in FIG. It is a pulse signal of phase. The first light receiving element 131 is synchronized with the pulse of the first light receiving element shutter opening signal, and accumulates charges corresponding to the amount of received light by opening the electronic shutter while receiving the pulse. On the other hand, when the reception of the pulse is interrupted, the first light receiving element 131 closes the electronic shutter and outputs a signal indicating the amount of charge E1 accumulated in the immediately preceding electronic shutter opened state. When the first light receiving element 131 outputs a signal indicating the accumulated charge amount E1, it discharges all accumulated charges. The first light receiving element 131 does not accumulate charges while the electronic shutter is closed.

  In FIG. 3, (D) the charge amount E1 of the first light receiving element indicates an increase or decrease in the charge amount E1 accumulated in the first light receiving element 131. As described above, the first light receiving element 131 receives only the reflected light Lr1 because the first wavelength plate 141 that transmits only the light wave of the wavelength band λ1 is disposed on the light receiving surface. Therefore, as shown in (B) reflected light Lr1 in the wavelength band λ1 in FIG. 3, (C) first light receiving element shutter opening signal in FIG. 3, and (D) charge amount E1 of the first light receiving element in FIG. The amount of charge E1 accumulated in the first light receiving element 131 increases while the reflected light Lr1 reaches the first light receiving element 131 and the electronic shutter of the first light receiving element 131 is in the open state. Note that, in (D) the charge amount E1 of the first light receiving element in FIG. 3, the charge amount E1 accumulated in the first light receiving element 131 increases in proportion to the time represented by Wa−τa.

  As shown in (E) the second light receiving element shutter opening signal in FIG. 3, the second light receiving element shutter opening signal output from the pulse signal generator 11 is the same as (C) the first light receiving element shutter opening signal in FIG. This is a pulse signal with an antiphase. The second light receiving element 132 operates in response to the second light receiving element shutter opening signal in the same manner as the operation in response to the first light receiving element shutter opening signal of the first light receiving element 131. Therefore, while the electronic shutter of the first light receiving element 131 is in the open state, the electronic shutter of the second light receiving element 132 is in the closed state, and while the electronic shutter of the first light receiving element 131 is in the closed state, the second light receiving element. The electronic shutter 132 is opened.

  In FIG. 3, (F) the charge amount E2 of the second light receiving element indicates an increase or decrease in the charge amount E2 accumulated in the second light receiving element 132. As described above, the second light receiving element 132 receives only the reflected light Lr1 because the first wave plate 141 that transmits only the light wave of the wavelength band λ1 is disposed on the light receiving surface. Therefore, as shown in (B) reflected light Lr1 in wavelength band λ1 in FIG. 3, (E) second light receiving element shutter opening signal in FIG. 3, and (F) charge amount E2 of the second light receiving element in FIG. The amount of charge E2 accumulated in the second light receiving element 132 increases while the reflected light Lr1 reaches the second light receiving element 132 and the electronic shutter of the second light receiving element 132 is open. Note that, in (F) the charge amount E2 of the second light receiving element in FIG. 3, the charge amount E2 accumulated in the second light receiving element 132 increases in proportion to the time represented by τa.

  As described above, the first light receiving element 131 receives and stores the reflected light Lr1 for the time represented by Wa−τa while the electronic shutter is opened. The second light receiving element 132 receives and stores the reflected light Lr1 only during the delay time τa while the electronic shutter is opened. Accordingly, the charge amount E1 stored in the first light receiving element 131 and the charge amount E2 stored in the second light receiving element 132 are both values corresponding to the delay time τa.

  As shown in (G) second light emitting element light emission signal in FIG. 3, the second light emitting element light emission signal output from the pulse signal generator 11 is a signal that repeats a pulse having a pulse width Wb with a period of 2 Wb. The value of the pulse width Wb is larger than the pulse width Wa. The second light emitting element 122 radiates the light wave signal L2 while receiving the pulse in synchronization with the pulse of the second light emitting element light emission signal. Here, it is assumed that reflected light Lr2, which is reflected light of the light wave signal L2, is generated from the detection object 52 (see FIG. 1) that has emitted the light wave signal L2. It is assumed that the detected object 52 is located farther than the detected object 51 with respect to the light receiver 13. In the following, as shown in (H) reflected wave Lr2 of wavelength λ2 in FIG. 3, the reflected light Lr2 reaches the light receiver 13 after a delay time τb has elapsed from the time when the lightwave signal L1 was emitted. explain. Note that the value of the delay time τb is smaller than the pulse width Wb.

  As shown in (I) first light-receiving element shutter opening signal in FIG. 3, the first light-receiving element shutter opening signal output from the pulse signal generator 11 is the same as the (G) second light-emitting element light emission signal in FIG. It is a pulse signal of phase. The third light receiving element 133 operates in response to the third light receiving element shutter open signal in the same manner as the operation of the first light receiving element 131 in response to the first light receiving element shutter open signal.

  In FIG. 3, (J) the charge amount E3 of the third light receiving element indicates an increase or decrease in the charge amount E3 accumulated in the third light receiving element 133. As described above, the third light receiving element 133 receives only the reflected light Lr2 because the second wavelength plate 142 that transmits only the light wave of the wavelength band λ2 is disposed on the light receiving surface. Therefore, as shown in (H) reflected wave Lr2 of wavelength λ2 in FIG. 3, (I) first light receiving element shutter opening signal in FIG. 3, and (J) charge amount E3 of the third light receiving element in FIG. The amount of charge E3 accumulated in the third light receiving element 133 increases while the reflected light Lr2 reaches the third light receiving element 133 and the electronic shutter of the third light receiving element 133 is in the open state. Note that in FIG. 3 (J) the charge amount E3 of the third light receiving element, the charge amount E3 accumulated in the third light receiving element 133 increases in proportion to the time represented by Wb−τb.

  As shown in (K) the fourth light receiving element shutter opening signal in FIG. 3, the fourth light receiving element shutter opening signal output from the pulse signal generator 11 is the same as (I) the third light receiving element shutter opening signal in FIG. This is a pulse signal with an antiphase. The fourth light receiving element 134 operates in response to the fourth light receiving element shutter opening signal in the same manner as the first light receiving element 131 operates in response to the first light receiving element shutter opening signal. From the above, while the electronic shutter of the third light receiving element 133 is in the open state, the electronic shutter of the fourth light receiving element 134 is in the closed state, while the electronic shutter of the third light receiving element 133 is in the closed state. The electronic shutter of the element 134 is opened.

  In FIG. 3, (L) the charge amount E4 of the fourth light receiving element indicates an increase or decrease in the charge amount E4 accumulated in the fourth light receiving element 134. As described above, the fourth light receiving element 134 receives only the reflected light Lr2 because the second wavelength plate 142 that transmits only the light wave in the wavelength band λ2 is disposed on the light receiving surface. Therefore, as shown in (H) reflected wave Lr2 of wavelength λ2 in FIG. 3, (K) fourth light receiving element shutter release signal in FIG. 3, and (L) charge amount E4 of the fourth light receiving element in FIG. The amount of charge E4 accumulated in the fourth light receiving element 134 increases while the reflected light Lr2 reaches the fourth light receiving element 134 and the electronic shutter of the fourth light receiving element 134 is in the open state. Note that, in (L) the charge amount E4 of the fourth light receiving element in FIG. 3, the charge amount E4 accumulated in the fourth light receiving element 134 increases in proportion to the time represented by τb.

  As described above, the third light receiving element 133 receives and stores the reflected light Lr2 for the time represented by Wb−τb while the electronic shutter is opened. The fourth light receiving element 134 receives and stores the reflected light Lr2 for the time represented by τb while the electronic shutter is opened. Therefore, the charge amount E3 stored in the third light receiving element 133 and the charge amount E4 stored in the fourth light receiving element 134 are values corresponding to the delay time τb.

  Based on the charge amount E1, the charge amount E2, the charge amount E3, and the charge amount E4 output by the operation of each light receiving element described above, the distance calculation unit 15 calculates the distance to the detected object. Specifically, the distance calculation unit 15 calculates the distance Ra to the detected object 51 based on the charge amount E1 output from the first light receiving element 131 and the charge amount E2 output from the second light receiving element 132. . The distance calculation unit 15 calculates the distance Rb to the detected object 52 based on the charge amount E3 output from the third light receiving element 133 and the charge amount E4 output from the fourth light receiving element 134. Hereinafter, with reference to FIG. 4, a process in which the distance calculation unit 15 calculates the distance Ra and the distance Rb will be described. FIG. 4 is an example of a flowchart illustrating processing executed by the distance calculation unit 15. The distance calculation unit 15 starts the process of the flowchart shown in FIG. 4 when power is supplied.

  In step S1, the distance calculation unit 15 executes a subroutine process of the distance calculation process A. The distance calculation process A is a process of calculating the distance Ra to the detected object 51 based on the charge amount E1 output from the first light receiving element 131 and the charge amount E2 output from the second light receiving element 132. Hereinafter, the distance calculation process A will be described with reference to FIG. FIG. 5 is an example of a flowchart showing details of the distance calculation processing A.

  In step S10, the distance calculation unit 15 determines whether or not a signal indicating the charge amount E1 has been received. Specifically, it is determined whether or not a signal indicating the charge amount E1 output from the first light receiving element has been received. If the distance calculation unit 15 determines that a signal indicating the charge amount E1 has been received, the process proceeds to step S11. On the other hand, if the distance calculation unit 15 determines that the signal indicating the charge amount E1 has not been received, the process proceeds to step S12.

  In step S11, the distance calculation unit 15 stores the value of the charge amount E1. Specifically, the distance calculation unit 15 stores the signal in the storage device based on a signal indicating the charge amount E1 output from the first light receiving element 131. When the value of the charge amount E1 previously stored in the storage device is already stored, the distance calculation unit 15 overwrites and updates the value of the charge amount E1 stored in the storage device with the latest value. When the process of step S11 is completed, the distance calculation unit 15 advances the process to step S12.

  In step S12, the distance calculation unit 15 determines whether or not a signal indicating the charge amount E2 has been received. Specifically, it is determined whether or not a signal indicating the charge amount E2 output from the first light receiving element has been received. If the distance calculation unit 15 determines that a signal indicating the charge amount E2 has been received, the process proceeds to step S13. On the other hand, if it is determined that the signal indicating the charge amount E2 has not been received, the distance calculation unit 15 ends the subroutine processing of the distance calculation processing A, and proceeds to step S2 shown in FIG.

  In step S13, the distance calculation unit 15 stores the value of the charge amount E2. Specifically, the distance calculation unit 15 stores the signal in the storage device based on the signal indicating the charge amount E2 output from the second light receiving element 132. When the value of the charge amount E2 previously stored in the storage device is already stored, the distance calculation unit 15 overwrites and updates the value of the charge amount E2 stored in the storage device with the latest value. When the process of step S13 is completed, the distance calculation unit 15 advances the process to step S14.

In step S14, the distance calculation unit 15 calculates the delay time τa. Specifically, the distance calculation unit 15 reads the values of the pulse width Wa, the charge amount E1, and the charge amount E2 stored in advance in the storage device, and calculates the delay time τa based on the following equation (2).
τa = Wa × E2 / (E1 + E2) (2)
The distance calculation unit 15 stores the calculated value of the delay time τa in the storage device. The delay time τa can be accurately calculated by calculating the delay time τa based on the charge amount E1 and the charge amount E2 accumulated at the opposite phase timing as in the above equation (2). When the distance calculation unit 15 completes the process of step S14, the process proceeds to step S15.

In step S15, the distance calculation unit 15 calculates the detection distance Da. Specifically, the distance calculation unit 15 reads the delay time τa calculated in step S14 and the value of the light velocity c stored in advance in the storage device, and calculates the detection distance Da based on the following equation (3). To do.
Da = c × τa (3)
When the process of step S15 is completed, the distance calculation unit 15 ends the subroutine process of the distance calculation process A and advances the process to step S2 shown in FIG.

  Returning to the description of FIG. 4, when the subroutine process of the distance calculation process A in step S1 is completed, the distance calculation unit 15 executes the subroutine process of the distance calculation process B in step S2. The distance calculation process B is a process of calculating the distance Rb to the detected object 52 based on the charge amount E3 output from the third light receiving element 133 and the charge amount E4 output from the fourth light receiving element 134. FIG. 6 is an example of a flowchart showing details of the distance calculation process B. The distance calculation process B shown in FIG. 6 includes the first light receiving element 131 as the third light receiving element 133, the charge amount E1 as the charge amount E3, and the second light reception as the distance calculation process A shown in FIG. The element 132 is replaced with the fourth light receiving element 134, the charge amount E1 is replaced with the charge amount E3, the charge amount E2 is replaced with the charge amount E4, the delay time τa is replaced with the delay time τb, and the detection distance Da is replaced with the detection distance Db. It is processing of. Therefore, detailed description of the distance calculation process B is omitted. When the distance calculation unit 15 completes the subroutine of the distance calculation process B in step S2, the process proceeds to step S3.

  In step S3, the distance calculation unit 15 determines whether or not the detection distance Rb is equal to or less than the threshold value Rth. The threshold value Rth is a threshold value of the detection distance Ra previously stored in the storage device by the distance calculation unit 15. The distance calculation unit 15 reads the values of the detection distance Rb and the threshold value Rth stored in the storage device, and compares the magnitudes of the values. If the distance calculation unit 15 determines that the detection distance Rb is equal to or less than the threshold value Rth, the process proceeds to step S4. On the other hand, if the distance calculation unit 15 determines that the detected distance Rb is greater than the threshold value Rth, the process proceeds to step S5.

  In step S4, the distance calculation unit 15 outputs the detection distance Ra. Specifically, the distance calculation unit 15 employs the value of the detection distance Ra stored in the storage device as a result of distance measurement, and outputs the value of the detection distance Ra as a measurement result. When completing the process of step S4, the distance calculator 15 advances the process to step S6.

  In step S5, the distance calculation unit 15 outputs the detection distance Rb. Specifically, the distance calculation unit 15 employs the value of the detection distance Rb stored in the storage device as a result of the distance measurement, and outputs the value of the detection distance Rb as the measurement result. When the distance calculation unit 15 completes the process of step S5, the process proceeds to step S6.

  According to the processing from step S3 to step S5, when the distance to the detected object is closer than the threshold value Rth, the value of the detection distance Ra measured with a relatively high resolution is adopted as the measurement result. Further, when the distance to the detected object is farther than the threshold value Rth, the value of the detection distance Rb is adopted as the measurement result.

  In step S6, the distance calculation unit 15 determines whether an end process has been executed. Specifically, the distance calculation unit 15 determines whether or not an operation for ending the operation of the distance measuring device 1 has been performed by the user, for example, turning off the power of the distance measuring device 1. When it is determined that the end process has been executed by the user, the distance calculation unit 15 ends the process of the flowchart of FIG. On the other hand, when it is determined that the end process has not been executed by the user, the distance calculation unit 15 returns the process to step S1 and repeats the process from step S1 to step S2.

  According to the operation of the pulse signal generator 11 and the processing of the distance calculator 15 described above, the distance to the detected object is calculated based on the light wave signal L1 and the light wave signal L2 having different pulse widths and wavelength bands. Processing can be performed in parallel. Here, since the value of the pulse width Wb of the light wave signal L2 is larger than the pulse width Wa of the light wave signal L1, the distance measuring device 1 measures the distance to the detected object based on the reflected light Lr2 of the light wave signal L2. Rather than measuring the distance based on the reflected light Lr1 of the lightwave signal L1, it is possible to measure a distance farther away. On the other hand, since the pulse width Wa of the lightwave signal L1 is smaller than the pulse width Wb of the lightwave signal L2, the distance measuring device 1 measures the distance to the detected object based on the reflected light Lr1 of the lightwave signal L1. The distance can be measured with a relatively higher resolution than when the distance is measured based on the reflected light of the signal L2. From the above characteristics, when the distance measuring device 1 is used, for example, a distance image having a large maximum detection distance and a high resolution in a short-distance region can be taken at a relatively high frame rate.

  Further, in the distance measuring device 1 according to the first embodiment described above, since each light receiving element is arranged in a single housing 135, when the distance measuring device 1 is attached to a vehicle, for example. Installation work is easy.

  In the first embodiment, the example in which the respective light receiving elements are arranged in a grid on the single casing 135 has been described. However, each light receiving element includes the pulse signal generation unit 11 and the distance calculation unit 15. As long as they are electrically connected, they may be arranged separately in a plurality of different housings. For example, two digital cameras are prepared, the image sensor of one digital camera is operated as the first light receiving element 131 and the second light receiving element 132, and the image sensor of the other digital camera is operated as the third light receiving element 133 and the fourth light receiving element. A structure that operates as the element 134 may be used. In such a configuration, when the first wave plate 141 is attached to the one digital camera and the second wave plate is attached to the other digital camera, the first wave plate 141 and the first wave plate as in the filter member 14 are obtained. There is no need to prepare a member in which the two-wavelength plate 142 is alternately arranged so as to correspond to each light receiving element. Further, if the light receiving elements are divided into a plurality of housings as in the above configuration, the degree of freedom in layout of the mounting space of the housings is increased. Also, four digital cameras are prepared, and the light receiving elements provided in each digital camera are operated as the first light receiving element 131, the second light receiving element 132, the third light receiving element 133, and the fourth light receiving element 134, respectively. The same effect as above can be obtained.

  In the first embodiment, an example in which the first wave plate 141 and the second wave plate 142 are alternately arranged has been described. However, the arrangement method of the first wave plate 141 and the second wave plate 142 is described above. Not exclusively. For example, as shown in FIG. 7, among the sections constituting the filter member 14, the number of sections configured by the second wavelength plate 142 is relatively larger than the number of sections configured by the first wavelength plate 141. The first wave plate 141 and the second wave plate 142 may be arranged so as to be. FIG. 7 is an example of a diagram illustrating how the filter member 14 is attached to the light receiver 13. The first wave plate 141 and the second wave plate 142 are arranged as shown in FIG. 7, and the light receiving elements are arranged so as to correspond to the respective wave plates, thereby arranging the wave plates and the light receiving elements as shown in FIG. Compared to the case, the light receiving area of the reflected light Lr2 can be increased. When the light receiving area of the reflected light Lr2 is increased, the amount of the reflected light Lr2 received per unit time is increased, so that the sensitivity of the reflected light Lr2 can be improved. As described above, the distance calculation unit 15 can calculate the distance to an object located far away based on the charge amount E3 and the charge amount E4 accumulated based on the reflected light Lr2. However, the longer the distance to the detected object, the longer the propagation distance of the reflected light Lr2. When the propagation distance becomes longer, the intensity of the reflected light Lr2 is likely to be attenuated, and it may be difficult to sufficiently accumulate the charge amount E3 and the charge amount E4 necessary for accurate distance calculation. Therefore, when detecting a distant object, it is preferable to arrange the wave plate and the light receiving element as shown in FIG. 7 to improve the sensitivity of the reflected light Lr2.

  In FIG. 7, among the sections constituting the filter member 14, the number of sections configured by the second wavelength plate 142 is relatively larger than the number of sections configured by the first wavelength plate 141. Although an example in which the sensitivity of the reflected light Lr2 is improved by arranging the first wavelength plate 141 and the second wavelength plate 142 is shown, the method of improving the sensitivity of the reflected light Lr2 is not limited to the above. For example, the area of the section constituted by the second wave plate 142 in the filter member 14 is increased, and the photosensitive surface of the corresponding light receiving element is increased in accordance with the area of the section, so that the reflected light Lr2 per unit time is increased. The amount of received light may be increased to improve the sensitivity.

  Further, the method of improving the sensitivity of the reflected light Lr2 is not limited to the method of increasing the light receiving area of the reflected light Lr2 as shown in FIG. 7, and for example, the light received by the third light receiving element 133 and the fourth light receiving element 134. The sensitivity of the reflected light Lr2 may be improved by setting the gain value for determining the sensitivity to a value relatively larger than the gain values of the first light receiving element 131 and the second light receiving element 132, for example.

  In the first embodiment, the example in which the light wave signal L1 in the wavelength band λ1 is emitted from the first light emitting element 121 and the light wave signal L2 in the wavelength band λ2 is emitted from the second light emitting element 122 has been described. The wavelength band λ1 and the wavelength band λ2 may be any wavelength band as long as the wavelength bands do not overlap and can be selected by the filter member 14. However, the distance measuring device 1 is used in an environment where humans and animals exist, for example, when the vehicle is provided with the distance measuring device 1 for the purpose of detecting obstacles around the vehicle. In this case, it is desirable that both the wavelength band λ1 and the wavelength band λ2 are outside the visible region. Waves such as light waves and sound waves are more likely to be attenuated as the propagation distance is longer, but are more difficult to attenuate as the wavelength of the wave is larger. Therefore, the wavelength band of the light wave used for detection of relatively distant objects (see above implementation). In the embodiment, it is preferable to set λ2) relatively long. Further, it is desirable that the light wave signal L1 and the light wave signal L2 have a constant wavelength and have high directivity, and the light wave signal L1 and the light wave signal L2 are preferably signals made of laser light.

  The distance measuring device 1 may be configured to be mounted on a vehicle. For example, the light emitter 12 may be mounted near the headlamp, the light receiver 13 may be provided on the front grill of the vehicle, and the distance to the object around the vehicle may be calculated by the distance calculation unit 15. In this case, the first light-emitting element 121 and the second light-emitting element each transmit a light wave to the surroundings of the vehicle, and the reflected light from the objects around the vehicle is received by the light receiver 13, whereby the distance to the objects around the vehicle Can be measured. When the distance measuring device 1 is mounted on a vehicle as described above, the headlamp provided on the left front side of the vehicle is the first light emitting element, and the headlamp provided on the right front side of the vehicle is the second light emission. A monitoring camera mounted on the vehicle in advance to capture the situation around the vehicle as an element may be configured as the light receiver 13.

  In the distance measuring apparatus 1 according to the first embodiment, two light wave signals, ie, the light wave signal L1 in the wavelength band λ1 and the light wave signal L2 in the wavelength band λ2, are transmitted and received, and the distance is determined based on each light wave signal. However, the distance measurement device 1 is not limited to two lightwave signals. For example, the distance measuring device may transmit and receive three lightwave signals having different wavelengths and different pulse periods, and measure the distance based on each lightwave signal.

  When configured to transmit and receive three lightwave signals as described above, the light emitter 12 includes a third light emitting element (not shown) that emits the lightwave signal L3 in the wavelength band λ3 different from the wavelength band λ1 and the wavelength band λ2. Further prepare. The third light emitting element emits the light wave signal L3 by blinking at a cycle 2Wc longer than the cycle 2Wa and shorter than the cycle 2Wb. The light receiver further includes a fifth light receiving element and a sixth light receiving element (not shown) that receive light waves in the wavelength band λ3, and is configured as a light receiver 33 shown in FIG. 8, for example. Each of the fifth light receiving element and the sixth light receiving element is disposed on the receiving surface F3 (a portion hatched with a wavy line in FIG. 8), and outputs a signal corresponding to the amount of received light. FIG. 8 is an example of a diagram illustrating how the filter member 34 is attached to the light receiver 33. The filter member further includes a third wavelength plate 143 (indicated by a dot pattern in FIG. 8) that transmits only light waves in the wavelength band λ3, and is configured as a filter member 34 shown in FIG. 8, for example.

  In addition to the process described with reference to FIG. 4, the distance calculation unit 15 performs a process of calculating the detection distance Rc based on signals output from the fifth light receiving element and the sixth light receiving element. Furthermore, when the value of the detection distance Rb is a relatively long distance, the distance calculation unit 15 adopts the value of the detection distance Rb as a measurement result, and when the value of the detection distance Rb is a relatively medium distance, When the value of the detection distance Rc is adopted as the measurement result and the value of the detection distance Rb is relatively close, a process of adopting the value of the detection distance Ra as the measurement result is performed.

  When the configuration is such that three lightwave signals are transmitted and received as described above, an object can be detected with three levels of resolution according to the detection distance.

  In addition, as shown in FIG. 8, it is preferable that the filter member 34 is configured such that the number of wave plates corresponding to the light wave signal is relatively increased as the period of the light wave signal is relatively large. By configuring the filter member 34 in this way, it is possible to improve the reception sensitivity of the lightwave signal used when measuring a relatively long distance.

  Further, the number of lightwave signals to be transmitted / received is not limited to three as described above, and four or more lightwave signals having different wavelengths and different pulse periods may be transmitted / received, and the distance may be measured based on each lightwave signal.

(Second Embodiment)
In the first embodiment, the distance measuring device 1 transmits an optical wave of a different wavelength band from the light emitter 12 and receives the optical wave by the light receiver 13 to measure the distance to the detected object. The waves transmitted and received by the distance measuring device are not limited to light waves. For example, the distance measuring device 2 according to the second embodiment may measure the distance to the detected object by transmitting and receiving ultrasonic waves having different wavelengths. Hereinafter, the distance measuring device 2 according to the second embodiment will be described.

  The functional configuration of the distance measuring device 2 will be described with reference to FIG. FIG. 9 is a block diagram showing a functional configuration of the distance measuring device 2. As shown in FIG. 9, the distance measuring device 2 includes an ultrasonic oscillator 22 instead of the light emitter 12 and a receiver 23 instead of the light receiver 13 in the distance measuring device 1 according to the first embodiment. . The distance measuring device 2 does not include the filter member 14. The configuration other than the above, that is, the pulse signal generation unit 11 and the distance calculation unit 15 are the same components as those described in the first embodiment, and perform the same operations and processes as those in the first embodiment. The description is omitted.

  The ultrasonic oscillator 22 is an oscillation device that oscillates ultrasonic waves having different frequencies. In the ultrasonic oscillator 22, the first light emitting element 121 included in the light emitter 12 according to the first embodiment is replaced with the first oscillation element 221, and the second light emitting element 122 is replaced with the second oscillation element 222. Is. Hereinafter, the first oscillation element 221 and the second oscillation element 222 are collectively referred to as an oscillation element. The first oscillating element 221 oscillates an ultrasonic signal U1 having a frequency f1, and the second oscillating element 222 oscillates an ultrasonic signal U2 having a frequency f2 different from the frequency f1. The first oscillating element 221 and the second oscillating element 222 are in accordance with signals output from the pulse signal generator 11 in the same manner as the first light emitting element 121 and the second light emitting element 122 described in the first embodiment. Each oscillates an ultrasonic signal.

  The receiver 23 is a receiving device that receives an ultrasonic signal emitted from the ultrasonic oscillator 22 and reflected by an object. The ultrasonic oscillator 22 includes the first light receiving element 131 provided in the light receiver 13 according to the first embodiment as the first receiving element 231, the second light receiving element 132 as the second receiving element 232, and the third light receiving element. The element 133 is replaced with the third receiving element 233, and the fourth light receiving element 134 is replaced with the fourth receiving element 234. Hereinafter, the first receiving element 231, the second receiving element 232, the third receiving element 233, and the fourth receiving element 234 are collectively referred to as a receiving element. Note that the receiver 23 is configured as an array antenna in which each receiving element is arranged in a lattice in a single casing in the same manner as the light receiving element in the first embodiment.

  The first receiving element 231 and the second receiving element 232 are vibrators having vibration characteristics for receiving only the ultrasonic wave having the frequency f1. Further, the third receiving element 233 and the fourth receiving element 234 are vibrators having vibration characteristics for receiving only the ultrasonic wave having the frequency f2. Thus, since each element can selectively receive an ultrasonic wave of a specific frequency, in the distance measuring device 2 according to the second embodiment, there is no need to include a member such as the filter member 14, Hardware configuration can be simplified. Each receiving element switches the reception state at different timings according to the signal output from the pulse signal generator 11, similarly to each light receiving element described in the first embodiment. Specifically, each receiving element is in a receiving state while receiving a pulse signal from the pulse signal generating unit 11, and accumulates electric charges according to the received ultrasonic signal. Each receiving element outputs an output signal corresponding to the accumulated charge amount to the distance calculation unit 15 when the pulse signal from the pulse signal generation unit 11 is interrupted. Each receiving element does not accumulate charges while it is not receiving a pulse signal. The distance calculation unit 15 calculates the distance to the detected object reflecting the ultrasonic signal based on the output signal output from each receiving element.

  According to the above configuration, the distance measuring device 2 transmits ultrasonic waves from the ultrasonic oscillator 22 and receives the reverberation sound reflected from the detected object by each receiving element provided in the receiver 23. The distance to the detection object that reflects the ultrasonic wave can be measured. Since ultrasonic waves are less susceptible to the influence of weather such as rain during propagation than light waves, the distance measuring device 2 can accurately measure the distance to a detected object even under bad weather conditions.

  In the second embodiment, the receiver 23 is configured as an array antenna in which each receiving element is arranged in a grid in a single housing. However, each receiving element is a pulse signal generator 11. And if it is electrically connected with the distance calculating part 15, the structure of the receiver 23 is not restricted above. For example, the receiver 23 may be configured as four individual microphone devices each including a first receiving element 231, a second receiving element 232, a third receiving element 233, and a fourth receiving element 234. According to such a configuration, it is not necessary to arrange each receiving element in a complicated manner, and wiring of each receiving element is easy. On the other hand, the configuration in which the receiver 23 as described above is an array antenna arranged in a grid in a single housing is suitable for generating a distance image based on the distance calculated by the distance calculation unit 15. It is.

  In the second embodiment, the example in which the distance measuring device 2 transmits and receives ultrasonic waves and measures the distance to the detected object has been described. However, the sound waves transmitted and received by the distance measuring device 2 are not limited to ultrasonic waves. The distance to the detected object may be calculated by transmitting and receiving sound waves having a frequency outside the ultrasonic range.

  The distance measuring device according to the present invention is useful as a distance measuring device that can detect a distant object and simultaneously detect a nearby object with high resolution.

Block diagram showing the functional configuration of the distance measuring device 1 An example of a diagram showing how the filter member 14 is attached to the light receiver 13 Example of timing chart showing operation of light emitting element and light receiving element An example of a flowchart showing processing executed by the distance calculation unit 15 Example of flowchart showing details of distance calculation processing A Example of flowchart showing details of distance calculation process B An example of a diagram showing how the filter member 14 is attached to the light receiver 13 An example of a diagram showing how the filter member 34 is attached to the light receiver 33 Block diagram showing the functional configuration of the distance measuring device 2

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Distance measuring device 11 Pulse signal generation part 12 Light emitter 13, 33 Light receiver 14, 34 Filter member 15 Distance calculating part 22 Ultrasonic oscillator 23 Receiver 51, 52 Detection object 121 1st light emitting element 122 2nd light emission Element 131 First light receiving element 132 Second light receiving element 133 Third light receiving element 134 Fourth light receiving element 135 Housing 141 First wave plate 142 Second wave plate 143 Third wave plate 221 First oscillation element 222 Second oscillation element 231 First receiving element 232 Second receiving element 233 Third receiving element 234 Fourth receiving element

Claims (11)

First light wave irradiation means for flashing at a predetermined first flashing period and emitting a first light wave in the first wavelength band toward another object, and flashing at a second flashing period different from the first flashing period. A light emitting means including at least a second light wave irradiation means for emitting a second light wave of a second wavelength band different from the first wavelength band toward another object;
Spectral transmission means including at least first filtering means for transmitting only light in the first wavelength band and second filtering means for transmitting only light in the second wavelength band;
A first light receiving means for receiving the first transmitted light reflected by the object and transmitted through the first filtering means, and outputting a first received light signal corresponding to the amount of the first transmitted light; and reflected by the object And at least a second light receiving means for receiving the second transmitted light that has passed through the second filtering means and outputting a second light receiving signal corresponding to the amount of the second transmitted light received,
A distance measuring device comprising distance calculating means for calculating a distance to the object based on the first light receiving signal and the second light receiving signal. The first blinking cycle is set longer than the second blinking cycle,
2. The distance measuring device according to claim 1, wherein an area through which the first filtering unit transmits the first transmitted light is set larger than an area through which the second filtering unit transmits the second transmitted light. The first light receiving means is configured by arranging light receiving elements having a light receiving surface of a predetermined unit area in a number corresponding to an area through which the first filtering means transmits the first transmitted light.
The distance measuring device according to claim 2, wherein the second light receiving unit is configured by arranging the light receiving elements in a number corresponding to an area through which the second filtering unit transmits the second transmitted light. The first blinking cycle is set longer than the second blinking cycle,
The distance measuring device according to claim 1, wherein the first light receiving unit is set to a light receiving sensitivity higher than a light receiving sensitivity set to the second light receiving unit. The first filtering means is a first plate-like member that transmits only light in the first wavelength band,
The distance measuring device according to claim 1, wherein the second filtering means is a second plate-like member that transmits only light in the second wavelength band. The spectral transmission means configures the first filtering means and the second filtering means by arranging the first plate-like member and the second plate-like member in a grid pattern,
The photosensitive means is a single camera provided with a plurality of light receiving elements. The light receiving element that receives light transmitted through the first plate-like member is used as the first light-receiving means, and the second plate-like member is used. The distance measuring device according to claim 5, wherein each of the light receiving elements that receive light passing through the light receiving element is configured as the second light receiving unit.   The distance measuring device according to claim 6, wherein the number of the first plate-like members arranged in a grid is larger than the number of the second plate-like members arranged. The photosensitive means uses the first camera that receives light transmitted through the first plate member as the first light receiving means, and the second camera that receives light transmitted through the second plate member as the second light reception. Each configured as a means,
The spectral transmission means uses the first plate-like member attached to the first camera as the first filtering means, and the second plate-like member attached to the second camera as the second filtering means. The distance measuring device according to claim 5, each of which is configured. The light emitting means is mounted in the vicinity of a vehicle headlamp,
The first light wave irradiation means emits the first light wave toward the periphery of the vehicle,
The second light wave irradiation means emits the second light wave toward the periphery of the vehicle,
The photosensitive means is mounted on a front grill of the vehicle,
The distance measuring device according to claim 1, wherein the distance calculating unit calculates a distance to an object existing around the vehicle. The first blinking cycle is set longer than the second blinking cycle,
The light emitting means blinks in a third blinking period shorter than the first blinking period and longer than the second blinking period, and has a third wavelength band different from the first wavelength band and the second wavelength band. A third light wave irradiation means for emitting three light waves toward another object;
The spectral transmission means further includes third filtering means for transmitting only light in the third wavelength band,
The photosensitive means receives third transmitted light reflected by the object and transmitted through the third filtering means, and outputs third received light signals according to the amount of received light of the third transmitted light. In addition,
The distance measuring device according to claim 1, wherein the distance calculating unit calculates a distance to the object based on the first light receiving signal, the second light receiving signal, and the third light receiving signal. A first sound wave emitting means for intermittently emitting a first sound wave in the first frequency band toward another object at a predetermined first generation period; and a second sound wave in a second frequency band different from the first frequency band. A sound wave generating means including at least a second sound wave emitting means for intermittently radiating the light at a second generation period different from the first generation period;
First receiving means for receiving only the reverberant sound of the first frequency band from the reverberant sound reflected from the object by the first sound wave and the second sound wave, and outputting a first received signal corresponding to the received amount; Receiving from the reverberant sound only reverberant sound in the second frequency band and outputting a second received signal in accordance with the received amount;
At least first distance calculating means for calculating a distance to the object based on the first received signal; and second distance calculating means for calculating a distance to the object based on the second received signal. A distance measuring device comprising distance calculating means.

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