Patent Application
20230314608
The present application claims the priority of Japanese Patent Application No. 2020-133326 filed on Aug. 5, 2020, the disclosure of which is hereby incorporated by reference in its entirety.
The present disclosure relates to an electromagnetic-wave detection apparatus.
In recent years, an apparatus that acquires information relating to surroundings from detection results obtained by a plurality of detectors configured to detect electromagnetic waves has been developed. Such an apparatus may sometimes detect, for example, a distance to a subject by acquiring an image including the subject captured by an imaging device and detecting electromagnetic waves including a reflected wave reflected by the subject. Here, a reflected wave came from a distant place is weak, and consequently, a highly sensitive detector is required. In contrast, a reflected wave came from a nearby place is extremely strong, and consequently, it saturates a detector and becomes a cause of measurement errors. Accordingly, for example, the apparatus disclosed in Patent Literature 1 radiates two types of laser beams, which are strong and weak laser beams, and when a detector included in the apparatus becomes saturated, the apparatus performs distance measurement using reflection of light emitted from a low-power laser oscillator included in the apparatus.
According to an embodiment of the present disclosure, an electromagnetic-wave detection apparatus includes a radiation system, a first detection unit, a calculation unit, and a radiation control unit. The radiation system radiates an electromagnetic wave toward a space in which a target is present. The first detection unit detects a reflected wave that is the electromagnetic wave radiated by the radiation system and reflected by the target. The calculation unit calculates a distance to the target based on detection information that is obtained by the first detection unit and that relates to the reflected wave. The radiation control unit causes the radiation system to radiate the electromagnetic wave. The radiation control unit causes a first electromagnetic wave to be radiated and then causes a second electromagnetic wave with a greater output than the first electromagnetic wave to be radiated. The calculation unit calculates the distance to the target based on the reflected wave of the first electromagnetic wave when the first detection unit becomes saturated with the reflected wave of the second electromagnetic wave.
The radiation system 111 includes a radiation unit 12 and a deflection unit 13. The light reception system 110 includes an incident unit 15, a separation unit 16, a first detection unit 20, a second detection unit 17, a switching unit 18, and a first subsequent-stage optical system 19. The control unit 14 includes an image-information acquisition unit 141, a radiation control unit 143, and a calculation unit 145. Details of each functional block of the electromagnetic-wave detection apparatus 10 will be described later.
In the drawings, dashed lines connecting the functional blocks each indicate a flow of a control signal or a flow of information that is transmitted and received. Each of the communications indicated by the dashed lines may be wired communication or may be wireless communication. In the drawings, solid arrows each indicate an electromagnetic wave in the form of a beam, and an object ob is a subject of the electromagnetic-wave detection apparatus 10. The subject may include, for example, objects such as a road, a median strip, a sidewalk, a roadside tree, and a vehicle and may include a person. There may be one or more objects ob.
The electromagnetic-wave detection apparatus 10 acquires an image including the subject and is capable of identifying the subject by detecting a reflected wave reflected by the subject. The electromagnetic-wave detection apparatus 10 includes the calculation unit 145 that measures a distance to the object ob, and the electromagnetic-wave detection apparatus 10 functions as a distance-measurement apparatus as mentioned above.
(Radiation System)
The radiation system 111 radiates an electromagnetic wave into a space in which the object ob is present. In the present embodiment, the radiation system 111 radiates an electromagnetic wave radiated by the radiation unit 12 toward the space in which the object ob is present via the deflection unit 13. As another example, the radiation system 111 may have a configuration in which the radiation unit 12 directly radiates an electromagnetic wave toward the object ob.
The radiation unit 12 radiates at least one of an infrared ray, a visible light ray, an ultraviolet ray, and a radio wave. In the present embodiment, the radiation unit 12 radiates an infrared ray. In addition, in the present embodiment, the radiation unit 12 radiates an electromagnetic wave in the form of a narrow beam of, for example, 0.5 degrees. The radiation unit 12 radiates the electromagnetic wave in pulses. The radiation unit 12 may include, for example, a light emitting diode (LED) as an electromagnetic-wave radiation element. Alternatively, the radiation unit 12 may include, for example, a laser diode (LD) as an electromagnetic-wave radiation element. The radiation unit 12 is switched to perform radiation of an electromagnetic wave and to stop radiation of the electromagnetic wave under control of the control unit 14. Here, the radiation unit 12 may form an LED array or an LD array that includes multiple electromagnetic-wave radiation elements arranged in an array and may radiate multiple beams simultaneously.
The deflection unit 13 causes the electromagnetic wave radiated by the radiation unit 12 to be output in different directions so as to change a position to be irradiated with the electromagnetic wave, which is radiated into the space in which the object ob is present. The deflection unit 13 may cause the electromagnetic wave to be output in different directions by reflecting the electromagnetic wave from the radiation unit 12 while changing the orientation of the deflection unit 13. For example, the deflection unit 13 causes the electromagnetic wave radiated by the radiation unit 12 to scan the object ob in a one-dimensional direction or a two-dimensional direction. Here, if the radiation unit 12 is configured as, for example, an LD array, the deflection unit 13 may reflect all the multiple beams that are output by the LD array so as to cause them to be output in the same direction. In other words, the radiation system 111 may include the single deflection unit 13 for the radiation unit 12 that includes one or more electromagnetic-wave radiation elements.
The deflection unit 13 is configured such that at least a portion of an irradiation region that is a space to which an electromagnetic wave is output is included in an electromagnetic-wave detection range of the light reception system 110. Thus, at least part of an electromagnetic wave that is radiated into the space in which the object ob is present via the deflection unit 13 is reflected by at least a portion of the object ob and may be detected by the light reception system 110. Here, an electromagnetic wave that is a radiation wave reflected by at least a portion of the object ob will hereinafter be referred to as a reflected wave. The radiation wave is an electromagnetic wave that is radiated from the radiation system 111 in multiple directions in the space in which the object ob is present.
The deflection unit 13 includes, for example, a micro-electromechanical systems (MEMS) mirror, a polygon mirror, and a galvanometer mirror. In the present embodiment, the deflection unit 13 includes a MEMS mirror.
The deflection unit 13 changes a direction in which the deflection unit 13 reflects an electromagnetic wave under control of the control unit 14. The deflection unit 13 may include an angle sensor such as, for example, an encoder and may notify the control unit 14 of an angle that is detected by the angle sensor as direction information regarding a direction in which the electromagnetic wave is reflected. In such a configuration, the control unit 14 may calculate an irradiation position of an electromagnetic wave on the basis of the direction information received from the deflection unit 13. The control unit 14 may also calculate the irradiation position on the basis of a drive signal that is input in order to cause the deflection unit 13 to change the direction in which the deflection unit 13 reflects the electromagnetic wave.
(Light Reception System)
In the following description, the phrase “electromagnetic waves including a reflected wave” refers to electromagnetic waves that include a reflected wave reflected by the object ob and that are incident on the light reception system 110. In other words, electromagnetic waves that are incident on the light reception system 110 may sometimes be referred to as “electromagnetic waves including a reflected wave” in order to distinguish them from the radiation wave. The electromagnetic waves including a reflected wave include not only the reflected wave, which is the electromagnetic wave that is radiated by the radiation system 111 and reflected by the object ob, but also outside light, such as sunlight, and light that is outside light reflected by the object ob.
The incident unit 15 is an optical system including at least one optical element and forms an image of the object ob, which is the subject. The optical element includes, for example, at least one selected from the group consisting of a lens, a mirror, a diaphragm, an optical filter, and the like.
The separation unit 16 is disposed between the incident unit 15 and a first image-forming position that is a position where the incident unit 15 forms an image of the object ob. The separation unit 16 separates the electromagnetic waves including a reflected wave in accordance with their wavelengths in such a manner that each wave travels in a first direction d1 or a second direction d2. The separation unit 16 may separate the electromagnetic waves including a reflected wave into the reflected wave and the other electromagnetic waves. The other electromagnetic waves may include, for example, light such as visible light.
In the present embodiment, the separation unit 16 reflects part of the electromagnetic waves including a reflected wave in the first direction d1 and enables another part of them to pass therethrough in the second direction d2. In the present embodiment, the separation unit 16 reflects, in the first direction d1, visible light that is environmental light, such as sunlight, reflected by the object ob. The separation unit 16 enables an infrared ray radiated by the radiation unit 12 and reflected by the object ob to pass therethrough in the second direction d2. As another example, the separation unit 16 may enable part of the electromagnetic waves including a reflected wave to pass therethrough in the first direction d1 and may reflect another part of the electromagnetic waves including a reflected wave in the second direction d2. The separation unit 16 may refract part of the electromagnetic waves including a reflected wave in the first direction d1 and may refract another part of the electromagnetic waves including a reflected wave in the second direction d2. Examples of the separation unit 16 include a half mirror, a beam splitter, a dichroic mirror, a cold mirror, a hot mirror, a metasurface, a deflection element, and a prism.
The second detection unit 17 is disposed on a path of an electromagnetic wave that travels in the first direction d1 from the separation unit 16. The second detection unit 17 is disposed at an image-forming position in the first direction d1 where an image of the object ob is formed or is disposed in the vicinity of this image-forming position. The second detection unit 17 detects an electromagnetic wave that has travelled in the first direction d1 from the separation unit 16.
The second detection unit 17 may be disposed with respect to the separation unit 16 in such a manner that a first travelling axis of the electromagnetic wave that travels in the first direction d1 from the separation unit 16 is parallel to a first detection axis of the second detection unit 17. The first travelling axis is the central axis of an electromagnetic wave that travels in the first direction d1 from the separation unit 16 and that propagates while spreading radially. In the present embodiment, the first travelling axis is an axis that is obtained by extending an optical axis of the incident unit 15 to the separation unit 16 and bending the optical axis at the separation unit 16 to make it parallel to the first direction d1. The first detection axis is an axis that passes through the center of a detection surface of the second detection unit 17 and that is perpendicular to the detection surface.
The second detection unit 17 may be disposed in such a manner that the gap between the first travelling axis and the first detection axis is equal to or less than a first gap threshold. Alternatively, the second detection unit 17 may be disposed in such a manner that the first travelling axis and the first detection axis coincide with each other. In the present embodiment, the second detection unit 17 is disposed in such a manner that the first travelling axis and the first detection axis coincide with each other.
The second detection unit 17 may be disposed with respect to the separation unit 16 such that a first angle formed by the first travelling axis and the detection surface of the second detection unit 17 is equal to or less than a first-angle threshold or such that the first angle is the same as a predetermined angle. In the present embodiment, the second detection unit 17 is disposed in such a manner that the first angle is 90 degrees.
In the present embodiment, the second detection unit 17 is a passive sensor. Specifically, in the present embodiment, the second detection unit 17 includes an element array. For example, the second detection unit 17 includes an imaging device such as an image sensor or an imaging array and captures an image formed by an electromagnetic wave focused at the detection surface so as to generate image information of a space including the captured object ob.
In the present embodiment, the second detection unit 17 is configured to detect light from a space, and more specifically, the second detection unit 17 captures a visible-light image. The second detection unit 17 outputs generated image information of the space as a signal to the control unit 14. The second detection unit 17 may capture images, such as an infrared-ray image, an ultraviolet-ray image, and a radio-wave image, other than a visible-light image.
The switching unit 18 is disposed on a path of an electromagnetic wave that travels in the second direction d2 from the separation unit 16. The switching unit 18 is disposed at a first image-forming position in the second direction d2 where an image of the object ob is formed or is disposed in the vicinity of this first image-forming position.
In the present embodiment, the switching unit 18 is disposed at the first image-forming position. The switching unit 18 has an action surface as on which an electromagnetic wave that has passed through the incident unit 15 and the separation unit 16 is incident. The action surface as is formed of multiple switching elements se arranged two-dimensionally. The action surface as is a surface that produces actions such as, for example, reflection and transmission of an electromagnetic wave, in at least one of a first state and a second state, which will be described below.
The switching unit 18 can switch the state of each of the switching elements se between the first state in which the switching element se causes an electromagnetic wave that is incident on the action surface as to travel in a third direction d3 and the second state in which the switching element se causes the electromagnetic wave to travel in a fourth direction d4. In the present embodiment, the first state is a first reflective state in which an electromagnetic wave that is incident on the action surface as is reflected in the third direction d3. The second state is a second reflective state in which the electromagnetic wave, which is incident on the action surface as, is reflected in the fourth direction d4.
More specifically, in the present embodiment, each of the switching elements se of the switching unit 18 has a reflective surface at which an electromagnetic wave is reflected. The switching unit 18 switches the state of each of the switching elements se between the first reflective state and the second reflective state by arbitrarily changing the orientation of the reflective surface of the switching element se.
In the present embodiment, the switching unit 18 includes, for example, a digital micro-mirror device (DMD). The DMD can switch the state of the reflective surface of each of the switching elements se between a state in which the reflective surface is inclined at +12 degrees with respect to the action surface as and a state in which the reflective surface is inclined at −12 degrees with respect to the action surface as by driving a micro-reflective surface included in the action surface as. The action surface as is parallel to a plate surface of a substrate of the DMD on which the micro-reflective surface is placed.
The switching unit 18 switches the state of each of the switching elements se between the first state and the second state under control of the control unit 14. As illustrated in
As illustrated in
The first detection unit 20 is disposed at a position at which the first detection unit 20 can detect an electromagnetic wave that is caused by the switching unit 18 to travel in the third direction d3 and then to further travel by passing through the first subsequent-stage optical system 19. The first detection unit 20 detects an electromagnetic wave that has passed through the first subsequent-stage optical system 19, that is, an electromagnetic wave that has travelled in the third direction d3, and outputs a detection signal.
The first detection unit 20 may be arranged with respect to the separation unit 16 such that a second travelling axis of an electromagnetic wave that travels in the second direction d2 from the separation unit 16 and that is caused to travel in the third direction d3 by the switching unit 18 is parallel to a second detection axis of the first detection unit 20. The second travelling axis is the central axis of an electromagnetic wave that travels in the third direction d3 from the switching unit 18 and that propagates while spreading radially. In the present embodiment, the second travelling axis is an axis that is obtained by extending the optical axis of the incident unit 15 to the switching unit 18 and bending the optical axis at the switching unit 18 to make it parallel to the third direction d3. The second detection axis is an axis that passes through the center of a detection surface of the first detection unit 20 and that is perpendicular to the detection surface.
The first detection unit 20 may be arranged in such a manner that the gap between the second travelling axis and the second detection axis is equal to or less than a second gap threshold. The second gap threshold may be the same as or different from the first gap threshold. Alternatively, the first detection unit 20 may be disposed in such a manner that the second travelling axis and the second detection axis coincide with each other. In the present embodiment, the first detection unit 20 is disposed in such a manner that the second travelling axis and the second detection axis coincide with each other.
The first detection unit 20 may be arranged with respect to the separation unit 16 such that a second angle formed by the second travelling axis and the detection surface of the first detection unit 20 is equal to or less than a second-angle threshold or such that the second angle is the same as a predetermined angle. The second-angle threshold may be the same as or different from the first-angle threshold. In the present embodiment, the first detection unit 20 is disposed in such a manner that the second angle is 90 degrees.
In the present embodiment, the first detection unit 20 is an active sensor that detects a reflected wave of an electromagnetic wave radiated from the radiation unit 12 toward the object ob. For example, the first detection unit 20 includes a single element, examples of which include an avalanche photodiode (APD), a photodiode (PD), and a distance-measurement image sensor. The first detection unit 20 may include an element array, examples of which include an APD array, a PD array, a distance-measurement imaging array, and a distance-measurement image sensor.
In the present embodiment, the first detection unit 20 transmits, as a signal, detection information indicating that a reflected wave has been detected to the control unit 14. More specifically, the first detection unit 20 detects an electromagnetic wave in the infrared band.
In the present embodiment, the first detection unit 20 is used as a detection element for measuring a distance to the object ob. In other words, the first detection unit 20 is an element included in a distance-measurement sensor, and an image is not necessarily formed at the detection surface of the first detection unit 20 as long as the first detection unit 20 can detect an electromagnetic wave. Thus, the first detection unit 20 does not need to be disposed at a second image-forming position that is a position at which an image is formed by the first subsequent-stage optical system 19. That is to say, in this configuration, the first detection unit 20 may be disposed at any position on a path of an electromagnetic wave that travels by passing through the first subsequent-stage optical system 19 after being caused by the switching unit 18 to travel in the third direction d3 as long as the first detection unit 20 is disposed at a position where an electromagnetic wave can be incident on the detection surface thereof from all angles of view.
With a configuration such as that described above, the electromagnetic-wave detection apparatus 10 matches a predetermined position in a space in image information with the optical axis of a reflected wave for measuring a distance to the predetermined position.
In the case illustrated in
(Control Unit)
The image-information acquisition unit 141 acquires image information of the space in which the object ob is present from the second detection unit 17, which detects an electromagnetic wave from the space. The image-information acquisition unit 141 may generate a captured image (see
The radiation control unit 143 controls the radiation system 111. For example, the radiation control unit 143 causes the radiation system 111 to radiate an electromagnetic wave and to stop radiation of the electromagnetic wave. For example, the radiation control unit 143 causes the deflection unit 13 to change a direction in which the deflection unit 13 reflects an electromagnetic wave. The radiation control unit 143 may acquire image information or a captured image from the image-information acquisition unit 141 and use it for controlling the radiation system 111.
The calculation unit 145 calculates a distance to the object ob on the basis of detection information acquired by the first detection unit 20. The calculation unit 145 can calculate a distance by, for example, the time-of-flight (ToF) method on the basis of acquired detection information.
As illustrated in
The calculation unit 145 acquires information regarding the above-mentioned signal including detection information. The calculation unit 145 includes, for example, a time-measurement large scale integrated circuit (LSI) and measures the period of time ΔT. The calculation unit 145 calculates a distance to the irradiation position by multiplying the period of time ΔT by the speed of light and dividing it by two.
Here, the control unit 14 may include one or more processors. The one or more processors may load a program from an accessible memory and operate as the image-information acquisition unit 141, the radiation control unit 143, and the calculation unit 145. The one or more processors may include at least one of a general-purpose processor that executes a specific function by loading a specific program and a dedicated processor for specific processing. The dedicated processor may include an application specific integrated circuit (ASIC). The one or more processors may include a programmable logic device (PLD). The PLD may include a field-programmable gate array (FPGA). The control unit 14 may include at least one of a system-on-a-chip (SoC) in which one or more processors cooperate with each other and a system-in-a-package (SiP).
(Radiation Control)
Although
First, in the case of acquiring range information at one point, the radiation control unit 143 causes the radiation system 111 to radiate multiple electromagnetic waves such that the magnitudes of the outputs of the multiple electromagnetic waves gradually increase. In other words, as illustrated in
The radiation control unit 143 may sometimes adjust the time interval between radiation of the first electromagnetic wave L1 and radiation of the second electromagnetic wave L2 on the basis of detection results that are obtained by the first detection unit 20 and that relate to the first reflected wave P1 and the second reflected wave P2. In particular, in the case where the first electromagnetic wave L1 and the second electromagnetic wave L2 are radiated from the radiation unit 12, if the first detection unit 20 detects a single reflected wave reflected by the object ob, and the width of the reflected wave is wide, the radiation control unit 143 increases the time interval between radiation of the first electromagnetic wave L1 and radiation of the second electromagnetic wave L2. Here, the phrase “the width of the reflected wave is wide” refers to the case in which the waveform of a detection signal that is obtained by the first detection unit 20 and that relates to the reflected wave has a width wider than that of a detection signal that relates to a single reflected wave, which is usually detected. Unlike the case illustrated in
Here, by identifying, on the basis of image information, the object ob irradiated with an electromagnetic wave, it can be determined whether there is a possibility that the reflected wave P3, which is formed of the overlapped first and second reflected waves P1 and P2, will be generated. Accordingly, the radiation control unit 143 may adjust the time interval between radiation of the first electromagnetic wave L1 and radiation of the second electromagnetic wave L2 on the basis of image information received from the image-information acquisition unit 141. The radiation control unit 143 may increase the time interval between radiation of the first electromagnetic wave L1 and radiation of the second electromagnetic wave L2 on the basis of the image information in the case where the electromagnetic wave is radiated onto one of the objects ob that is recognized as the object ob (e.g., a road, a guardrail, or the like) inclined with respect to the optical axis. In the image information illustrated in
In addition, the radiation control unit 143 may adjust the first electromagnetic wave L1 and the second electromagnetic wave L2 on the basis of the range information that has already been acquired. For example, when the radiation unit 12 radiates an electromagnetic wave to multiple objects present in a space, and the ratio or the difference between the distance to one of the objects and the distance to another one of the objects is large, the radiation control unit 143 may increase the ratio of magnitude of output between the first electromagnetic wave L1 and the second electromagnetic wave L2 (the ratio between r1 and r2 in
(Light-Source Driving Device)
In order to generate multiple electromagnetic waves such that the magnitudes of the outputs of these electromagnetic waves gradually increase, the radiation unit 12 may include a light-source driving device, which will be described below.
In the light-source driving device, power is supplied to the capacitor C1 by an alternating-current power supply through a resistor R5, and as a result, an electric charge accumulates in the capacitor C1. Upon receiving the first control signal, the first transistor Q2 causes the capacitor C1 to discharge part of the electric charge so as to cause the laser diode DDD to emit light so that the first electromagnetic wave L1 is radiated. Upon receiving the second control signal, the second transistor Q3 causes the capacitor C1 to discharge the rest of the electric charge so as to cause the laser diode DDD to emit light so that the second electromagnetic wave L2 is radiated. Here, a capacitor C2 illustrated in
As described above, according to the present embodiment, the electromagnetic-wave detection apparatus 10 can perform, with the above-described configuration, accurate electromagnetic-wave detection without being affected by saturation or the like. Therefore, the electromagnetic-wave detection apparatus 10 functioning as a distance-measurement apparatus can detect a distance to a subject accurately.
(Variations)
Although the present disclosure has been described with reference to the drawings and on the basis of the embodiment, it is to be noted that variations and various corrections can be easily made by those skilled in the art on the basis of the present disclosure. Therefore, it is to be noted that such variations and corrections are included in the scope of the present disclosure.
In the above-described embodiment, the electromagnetic-wave detection apparatus 10 is configured to generate range information by the Direct ToF method for directly measuring the period of time from when a laser beam is radiated until the laser beam returns. However, the electromagnetic-wave detection apparatus 10 is not limited to having such a configuration. For example, the electromagnetic-wave detection apparatus 10 may generate range information by the Flash ToF method, in which an electromagnetic wave is radiated at regular intervals and in which the period of time from when the electromagnetic wave is radiated until the electromagnetic wave returns is indirectly measured by using the phase difference between the radiated electromagnetic wave and the returned electromagnetic wave.
Alternatively, the electromagnetic-wave detection apparatus 10 may employ another ToF method such as, for example, the phased ToF method and generate range information.
In the above-described embodiment, although the switching unit 18 can switch the travelling direction of an electromagnetic wave that is incident on the action surface as between two directions, the switching unit 18 may switch the travelling direction of the electromagnetic wave between three or more directions instead of two directions.
In the above-described embodiment, in the switching unit 18, the first state is the first reflection state in which an electromagnetic wave that is incident on the action surface as is reflected in the third direction d3, and the second state is the second reflection state in which an electromagnetic wave that is incident on the action surface as is reflected in the fourth direction d4. However, each of these states may be another state.
For example, the first state may be a transmission state in which an electromagnetic wave that is incident on the action surface as is allowed to pass through the action surface as and travel in the third direction d3. More specifically, switching elements included in a switching unit 181 that is an alternative to the above-described switching unit 18 and that has a configuration different from that of the switching unit 18 may each include a shutter having a reflective surface at which an electromagnetic wave is reflected in the fourth direction d4. In the switching unit 181 having such a configuration, the state of each of the switching elements may be switched between the transmission state, which is the first state, and the reflection state, which is the second state, by opening and closing the shutter of the switching element.
An example of the switching unit 181 having such a configuration may be a switching unit that includes a MEMS shutter in which multiple shutters that are openable and closable are arranged in an array. Another example of the switching unit 181 may be a switching unit that includes a liquid-crystal shutter whose state can be switched, in accordance with the alignment of liquid-crystal molecules, between a reflection state in which an electromagnetic wave is reflected and a transmission state in which an electromagnetic wave is allowed to pass therethrough. In the switching unit 181 having such a configuration, the state of each of the switching elements may be switched between the transmission state, which is the first state, and the reflection state, which is the second state, by switching the alignment of liquid-crystal molecules of the switching element.
In the electromagnetic-wave detection apparatus 10, the light reception system 110 may further include a second subsequent-stage optical system and a third detection unit. The second subsequent-stage optical system is disposed in the fourth direction d4 from the switching unit 18 and forms an image of the object ob. The third detection unit is disposed on a path of an electromagnetic wave that is caused to travel in the fourth direction d4 by the switching unit 18 and that further travels by passing through the second subsequent-stage optical system, and the third detection unit detects an electromagnetic wave that has travelled in the fourth direction d4.
In the above-described embodiment, the electromagnetic-wave detection apparatus 10 has a configuration in which the second detection unit 17 is a passive sensor and in which the first detection unit 20 is an active sensor. However, the electromagnetic-wave detection apparatus 10 is not limited to having such a configuration. For example, in the electromagnetic-wave detection apparatus 10, advantageous effects the same as, and/or similar to, those of the above-described embodiment can be obtained both in the case where the second detection unit 17 and the first detection unit 20 are active sensors and in the case where the second detection unit 17 and the first detection unit 20 are passive sensors.
In the present embodiment, the calculation unit 145 measures a distance to the object ob, and the electromagnetic-wave detection apparatus 10 has a function of serving as a distance-measurement apparatus. Here, the electromagnetic-wave detection apparatus 10 is not limited to being configured to measure a distance. For example, the electromagnetic-wave detection apparatus 10 may be a driver-assistance apparatus that detects the presence of the object ob, which is an obstacle on a road, and gives a warning. In this case, the control unit 14 does not need to include the calculation unit 145. As another example, the electromagnetic-wave detection apparatus 10 may be a surveillance apparatus that detects the presence of the object ob, which is a suspicious object in the surroundings.
Among the image-information acquisition unit 141, the radiation control unit 143, and the calculation unit 145, some of them may be provided separately from the control unit 14 instead of being included in the control unit 14. For example, the calculation unit 145 may be provided as a control device that is independent of the control unit 14.
Although a representative example has been described in the above embodiment, it is obvious to those skilled in the art that many changes and substitutions can be made within the gist and the scope of the present disclosure. Thus, the present disclosure shall not be considered to be limited to the above-described embodiment, and variations and various changes can be made without departing from the scope of the claims. For example, some of the configuration blocks illustrated in the configuration diagrams of the embodiment can be combined into a single configuration block, or one of the configuration blocks may be divided into multiple configuration blocks.
Although a solution of the present disclosure is described in the form of an apparatus, the present disclosure can also be realized in forms including the apparatus and furthermore can be realized as a method, a program, or a storage medium recording a program that is substantially equivalent to the apparatus, and it shall be understood that the scope of the present disclosure includes these forms as well.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-133326 | Aug 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/028977 | 8/4/2021 | WO |
