Optical device and moving device

Abstract

Provided are: an optical device in which the accuracy of detecting an object can be maintained or improved while avoiding a rise in the temperature of a light emitting part; and a moving device on which the optical device is mounted. An optical device 1 includes: a light-emitting part 10 having a plurality of light-emitting elements L for emitting light onto an object OBJ; a light-receiving part 20 having a plurality of light-receiving elements S that receive light reflected by the object OBJ and output light reception signals; and a control device 100 for acquiring distance information about the object OBJ on the basis of the respective light reception signals of the plurality of light-receiving elements S. The light emission intensity of each of the light-emitting elements L is controlled on the basis of the distance information about the object OBJ so that the light-receiving intensity of each of the light-receiving elements S is equal to or higher than a reference light-receiving intensity.

Description

Optical and moving devices

[0001] The present invention relates to optical devices such as LiDAR (Light Detection and Ranging) systems.

[0002] Optical devices that constitute a LiDAR system mounted on a vehicle are known and detect targets (objects) in front of the vehicle, such as pedestrians, preceding vehicles, and / or oncoming vehicles. In these optical devices, light emitted from a light-emitting unit is irradiated onto the object, and the light reflected by the object is received by a light-receiving unit, and the object is detected based on the light-receiving result. When the temperature of the light-emitting unit increases due to heat generated during light emission, the light-emitting output of the light-emitting unit decreases, which in turn reduces the intensity of the light received by the light-receiving unit and reduces the accuracy of target detection. Therefore, a technology has been proposed that narrows the area illuminated by the light-emitting unit when the temperature of the light-emitting unit reaches a temperature that reduces the light-emitting output, thereby avoiding a decrease in the intensity of the light received by the light-receiving unit (see, for example, Patent Document 1).

[0003] International Publication WO2023 / 074902A1

[0004] However, an object that would have been illuminated by light in the original illumination area falls outside the narrowed illumination area, and the object cannot be detected.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical device or the like that can maintain or improve the detection accuracy of an object while avoiding a temperature rise in the light-emitting section.

[0006] The optical device of the present invention is an optical device comprising: a light-emitting unit having a plurality of light-emitting elements that emit light to be irradiated onto an object; a light-receiving unit having a plurality of light-receiving elements that receive the light reflected by the object and output a light-receiving signal; and a control device that acquires distance information of the object based on the light-receiving signals of each of the plurality of light-receiving elements, wherein the control device controls the light-emitting intensity of each of the plurality of light-emitting elements based on the distance information of the object so that the light-receiving intensity of each of the plurality of light-receiving elements is equal to or greater than a reference light-receiving intensity.

[0007] According to the optical device having this configuration, it is possible to maintain or improve the detection accuracy of the object while avoiding a temperature rise in the light-emitting section.

[0008] 1 is a diagram illustrating the configuration of an optical device according to one embodiment of the present invention; 2 is a diagram illustrating the configuration of a group of light-emitting elements; 3 is a diagram illustrating the configuration of a group of light-receiving elements; 4 is a diagram illustrating the configuration of a vehicle (mobile device) according to one embodiment of the present invention; 5 is a flowchart illustrating the function of an optical device according to one embodiment of the present invention; 6 is a diagram illustrating the correlation between distance information and target light-emitting intensity; 7 is a diagram illustrating the correlation between received light intensity according to light-emitting intensity and distance information; 8 is an exemplary diagram illustrating the control mode of the light-emitting intensity of each light-emitting element; 9 is a diagram illustrating the configuration of an optical device according to another embodiment of the present invention;

[0009] 1 as a first embodiment of the present invention is used as a detection device / image capture device that detects and captures an object OBJ by receiving light reflected from the object OBJ, as well as a distance measuring device that acquires distance information to the object OBJ. The optical device 1 employs a technology called LiDAR (Light Detection and Ranging), which calculates the distance to the object OBJ based on the time it takes to receive reflected light from the object OBJ and the phase of the reflected light.

[0010] (Light Emitting Unit) The light emitting unit 10 includes a light source 11 and a light emitting optical system 12. The light source 11 is, for example, a vertical cavity surface emitting laser (VCSEL) and is composed of a first specified number N1 (N1 is plural) of light emitting elements L arranged two-dimensionally. For example, as shown in FIG. 2A , the light source 11 is composed of a first specified number N1 (N1 = n1 × m1) of light emitting elements L arranged in an n1 × m1 matrix in the u1 direction (left-right direction) and the v1 direction (up-down direction). Each light emitting element L emits light in a direction perpendicular to each of the u1 direction and the v1 direction.

[0011] Each of n1 and m1 may be changed to various numbers. One of n1 and m1 may be "1." The light-emitting element L is, for example, configured with a semiconductor laser. The semiconductor laser emits, for example, infrared light (e.g., illumination light having a wavelength of 905 nm, which is included in the near-infrared range) that has little effect on the human eye.

[0012] The light-emitting optical system 12 is an optical system for irradiating the light emitted from the light source 11 toward the object OBJ. The light source 11 is disposed at the focal plane of the light-emitting optical system 12. The light-emitting optical system 12 irradiates the object OBJ with light emitted or projected from the light-emitting element L of the light source 11 as collimated light. Each of the light-emitting optical systems 12 is composed of a lens group made up of multiple lenses (e.g., 5 to 7 lenses). The light-emitting optical system 12 may include an aperture (a light-blocking member with an opening) that limits the illumination light to adjust the beam diameter (beam width). The shape of the aperture opening may be designed to be elliptical, rectangular, or other shape to match the shape of the illumination light.

[0013] (Light Receiving Unit) The light receiving unit 20 includes a light receiving sensor 21 and a light receiving optical system 22. The light receiving sensor 21 is composed of a second specified number N of light receiving elements S arranged two-dimensionally. For example, as shown in FIG. 2B , the light receiving sensor 21 is composed of a second specified number N (N = n × m) of light receiving elements S arranged in an n × m matrix in the u direction (left-right direction) and v direction (up-down direction).

[0014] Each of n2 and m2 may be changed to various numbers. One of n2 and m2 may be "1". The light receiving element S is an element that receives reflected light from the object OBJ, performs photoelectric conversion, and outputs a signal. The light receiving element S is composed of a PD (Photo Diode), APD (Avalanche Photo Diode), SPAD (Single Photo Avalanche Diode), etc.

[0015] The light-receiving optical system 22 is an optical system for causing the light-receiving sensor 21 to receive light reflected from the object OBJ. The light-receiving sensor 21 is disposed on the focal plane of the light-receiving optical system 22. The light-receiving optical system 22 focuses the light reflected from the object OBJ onto the light-receiving element S of the light-receiving sensor 21. Similar to the light-emitting optical system 12, the light-receiving optical system 22 is configured with a lens group made up of multiple lenses (e.g., 5 to 7 lenses). The light-receiving optical system 22 may have an optical filter member (band-pass filter) that passes only desired light and blocks (absorbs) other unnecessary light.

[0016] (Control Device) The control device 100 is configured to control the operation of the onboard equipment of the vehicle V as well as the operation of the optical device 1. The control device 100 includes an arithmetic processing device (e.g., a CPU, a processor core, etc.) and a storage device (memory, etc.). The control device 100 is configured so that the arithmetic processing device (hardware) reads a program (software) and data from the storage device and performs arithmetic processing on the data in accordance with the program, thereby executing a designated task.

[0017] The control device 100 is configured to control the light emission intensity of each light-emitting element L. The control device 100 is configured to drive the light-emitting unit 10 or each light-emitting element L at a specified drive voltage and / or a specified drive frequency, and to control the output (light intensity of illumination light) of the light-emitting unit 10. The control device 100 may control the operation of the light-emitting unit 10 to make the illumination light pulse light or may perform intensity modulation of the illumination light to generate signal light.

[0018] 1, the control device 100 includes a distance information acquisition unit 110 and a contact determination unit 120. Each of the distance information acquisition unit 110 and the contact determination unit 120 is configured to execute a designated task by having an arithmetic processing device (hardware) read a program (software) and data from a storage device and perform arithmetic processing on the data in accordance with the program.

[0019] The distance information acquisition unit 110 is configured to acquire distance information of the object OBJ based on the time from when illumination light is emitted from the light-emitting unit 10 (light-emitting time) to when the light-receiving unit 20 receives the light reflected from the object OBJ (light-receiving time). The distance information acquisition unit 110 may acquire a signal from the light-receiving unit 20 at a specified frequency. In addition to or instead of the time until the light reflected from the object OBJ is received, the distance information acquisition unit 110 may acquire distance information based on the phase of the light reflected from the object OBJ. Specifically, the distance information acquisition unit 110 may acquire the difference (phase difference) between the phase of the signal from the light-emitting unit 10 and the phase of the signal output from the light-receiving unit 20 and multiply the phase difference by the speed of light to acquire the distance information of the object OBJ.

[0020] The contact determination unit 120 is configured to determine the likelihood of contact between the object OBJ and the vehicle V, based on distance information of the object OBJ, such as traffic participants such as other vehicles and pedestrians, as well as roadside structures, acquired by the distance information acquisition unit 110. When the contact determination unit 120 determines that there is a high likelihood of contact between the vehicle V and the object OBJ, the control device 100 may be configured to decelerate, stop, or change direction (steer) the vehicle V, or to output an alert to alert passengers of the vehicle V.

[0021] (Mobile Device) The optical device 1 having the above configuration is mounted on, for example, a vehicle V (four-wheeled automobile) which is a mobile device according to one embodiment of the present invention shown in Fig. 3. The mobile device may be a two-wheeled automobile or a robot with a mobile function (or an autonomous mobile function), in addition to the vehicle V. The vehicle V may be a vehicle driven by a person or an automatically driven vehicle.

[0022] The light-emitting unit 10 is housed inside the housing of the headlight HL of the vehicle V together with a headlight light source (a light source that irradiates the front with white visible light). The light-emitting unit 10 may be attached to a location on the vehicle body below the headlight HL. The light-receiving unit 20 is attached to the vehicle V or its body at a location below the headlight HL. The control device 100 is disposed in an appropriate location inside the vehicle V (such as the space below the floor of the cabin space).

[0023] First Embodiment A first embodiment of a method for controlling the light emission intensity of each light-emitting element L using the optical device 1 configured as described above, particularly the control device 100, will be described with reference to the flowchart shown in Fig. 4. In the first embodiment, a first designated number N1, which is the number of light-emitting elements L, is smaller than a second designated number N2, which is the number of light-receiving elements S (n1 < n2 and m1 < m2).

[0024] First, distance information of the object OBJ is acquired (FIG. 4 / STEP 10). Each of the first specified number N1 of light-emitting elements L is sequentially switched from a non-emission state to an emission state in a specified order and at a specified cycle. The switching of the i-th light-emitting element L (i=q mod N1 (q=1, 2, . . . N1)) from an emission state to an emission non-emission state and the switching of the i+1-th light-emitting element L subsequent to the i-th light-emitting element L from an emission non-emission state to an emission state are performed simultaneously or almost simultaneously.

[0025] The pulsed reflected light is received by each of the plurality of light receiving elements S constituting the i-th light receiving element group corresponding to the i-th light emitting element L in the light emitting state, and a signal corresponding to the reflected light is transmitted to the control device 100. Based on the signal, the control device 100 generates a distance image composed of a second specified number N2 of pixels corresponding to each of the second specified number N2 of light receiving elements S, with each pixel having the distance to the object OBJ as its pixel value.

[0026] Next, a fitting process is performed (FIG. 4 / STEP 12). Specifically, distance information for each of the second specified number N2 of pixels in the distance image is extracted as distance information corresponding to each of the first specified number N1 of light-emitting elements L. For this extraction process, for example, a convolution process is performed. The convolution process uses a kernel f (which is a matrix of (n2-n1) x (m2-m1)), as expressed in relational expression (1).

[0027] (f*g)(c1,c2)=Σ a1,a2 f (a1, a2) g (c1 - a1, c2 - a2) c1 = n2 - a1, c2 = m2 - a2, a1 = 1 ~ n2 - n1, a2 = 1 ~ m2 - m1 (1).

[0028] The parameters of the kernel f are defined by, for example, relational expression (2) using the standard deviation σ of the parameters.

[0029] f(a1,a2)=1 / (2πσ 2 ) × exp(-(a1 2 + a2 2 ) / 2σ 2 ) ...(2).

[0030] Instead of the convolution process, the distance information of each of the second specified number N2 of pixels in the distance image may be extracted as distance information corresponding to each of the first specified number N1 of light-emitting elements L by performing a weighted sum of the distance information of each of multiple adjacent or nearby pixels in the distance image. The weighting coefficients are appropriately selected so that the result of the weighted sum is similar to the result of the convolution process.

[0031] Next, effective light-emitting elements and ineffective light-emitting elements are identified (FIG. 4 / STEP 14). "Ineffective light-emitting elements" refer to light-emitting elements L among the first specified number N1 of light-emitting elements L that correspond to distance information (distance) included in a specified distance range. The specified distance range is, for example, a range of distances longer than one specified distance (e.g., 100 m, 200 m, 500 m, 1 km, etc.). The specified distance range may also be a range of distances shorter than another specified distance (e.g., 0.10 m, 0.20 m, 0.50 m, etc.). "Effective light-emitting elements" refer to light-emitting elements L among the first specified number N1 of light-emitting elements L, excluding ineffective light-emitting elements.

[0032] Next, the target light emission intensity of each light emitting element L is set (FIG. 4 / STEP 16). The target light emission intensity of an ineffective light emitting element L is set to 0. The target light emission intensity of an effective light emitting element L is set based on the distance represented by the distance information corresponding to that effective light emitting element so that the light received intensity of the light receiving element S corresponding to that effective light emitting element is equal to or greater than the reference light received intensity.

[0033] Specifically, the target light emission intensity of an effective light emitting element is set based on the distance represented by the distance information corresponding to the effective light emitting element, in accordance with the correlation between distance information (distance) and the target light emission intensity. Figure 5 shows a curve representing this correlation. For example, if the distance information (distance) of a certain effective light emitting element is 10 m, the target light emission intensity of the effective light emitting element is set to approximately 100 W. Figure 6 illustrates an example of how the target light emission intensity of each light emitting element L is set. Each white rectangular area corresponds to an ineffective light emitting element whose target light emission intensity is set to 0. The other rectangular areas correspond to effective light emitting elements, and the lower the brightness, the higher the target light emission intensity.

[0034] The correlation between distance information (distance) and target light emission intensity as shown in FIG. 5 is set based on the correlation between the distance information (distance) corresponding to the light-emitting element L and the light-receiving intensity of the light-receiving element S, depending on the light-emitting intensity of the light-emitting element L. In FIG. 7 , curves representing the correlation when the light-emitting intensity of the light-emitting element L is 10 W, 25 W, 50 W, 75 W, and 100 W are shown by dotted lines, dashed lines, one-dot chain lines, two-dot chain lines, and solid lines, respectively. The correlation may be obtained in advance through experiments. As shown in FIG. 7 , as the distance to the object OBJ decreases, the light-receiving intensity (more precisely, the output signal intensity corresponding to the received light intensity) of the light-receiving element S corresponding to the light-emitting element L gradually increases. As the distance decreases, the saturated light-receiving intensity, which is approximately the maximum value, is reached, and the light-receiving intensity of the light-receiving element S hardly increases even when the distance decreases further. 7, when the light-emitting intensity of the light-emitting element L is 10 W, 25 W, 50 W, 75 W, and 100 W, the distances at which the saturated light-receiving intensity is reached are approximately 1 m, approximately 2 m, approximately 5 m, approximately 8 m, and approximately 10 m, respectively. That is, the higher the light-emitting intensity of the light-emitting element L, the longer the distance at which the saturated light-receiving intensity is reached.

[0035] In this embodiment, the target light emission intensity according to the distance represented by the distance information of the object OBJ is set to a light emission intensity corresponding to a value (γ×saturation received light intensity (γ=0.70 to 0.90)) that is lower than the saturated received light intensity according to the distance. This sets the correlation between the distance information (distance) and the target light emission intensity as shown in FIG. 5.

[0036] It is determined whether the sum ΣLI of the target light-emitting intensities of the light-emitting elements L is equal to or less than a threshold value LI0 (FIG. 4 / STEP 20). If the determination result is negative (FIG. 4 / STEP 20...NO), the target light-emitting intensities of the light-emitting elements L, particularly the effective light-emitting elements, are reset by, for example, lowering the value of γ (FIG. 4 / STEP 18). Note that if the determination result is negative (FIG. 4 / STEP 20...NO), the specified distance range may be expanded (the specified distance may be set shorter) to increase the number of ineffective light-emitting elements (FIG. 4 / STEP 16).

[0037] If the determination result is affirmative (FIG. 4 / STEP 20...YES), the light emission intensity of each light-emitting element L is controlled to the target light emission intensity (FIG. 4 / STEP 22). This ends the series of light emission control processes, but the light emission control processes are repeated until the search for the object OBJ is completed. Of the first specified number N1 of light-emitting elements L, a light-emitting element L or a group of light-emitting elements that has been identified as an ineffective light-emitting element for a first specified number of times may thereafter be fixed as an ineffective light-emitting element for a second specified number of times (or until the search for the object OBJ is completed). In the light emission control processes for the second specified number of times, the process of identifying effective and ineffective light-emitting elements (FIG. 4 / STEP 14) may be omitted.

[0038] Second Embodiment In a second embodiment, a first designated number N1, which is the number of light-emitting elements L, is greater than a second designated number N2, which is the number of light-receiving elements S (n2<n1 and m2<m1).

[0039] First, distance information of the object OBJ is acquired (FIG. 4 / STEP 10). A plurality of light-emitting elements L constituting each of the light-emitting element groups that are part of the first specified number N1 of light-emitting elements L are sequentially switched from a non-emission state to an emission state in a specified order and at a specified cycle. The switching of the i-th light-emitting element L (i=q mod N1 (q=1, 2, . . . N1)) from an emission state to an emission non-emission state and the switching of the i+1-th light-emitting element L subsequent to the i-th light-emitting element L from an emission non-emission state to an emission state are performed simultaneously or almost simultaneously.

[0040] When the jth light receiving element S corresponding to the jth light emitting element group including the i-th light emitting element L in an emitting state receives the pulsed reflected light, a signal corresponding to the reflected light is transmitted to the control device 100. Based on the signal, the control device 100 generates a distance image composed of a first specified number N1 of pixels corresponding to each of the first specified number N1 of light emitting elements L, with each pixel having the distance to the object OBJ as its pixel value.

[0041] In the second embodiment, unlike the first embodiment, the fitting process (FIG. 4 / STEP 12) is omitted and effective and ineffective light-emitting elements are identified (FIG. 4 / STEP 14). The processing content of the second embodiment thereafter is the same as that of the first embodiment, and therefore further explanation will be omitted.

[0042] Third Embodiment In a third embodiment, the first designated number N1, which is the number of light-emitting elements L, is equal to the second designated number N2, which is the number of light-receiving elements S (n1=n2 and m1=m2).

[0043] First, distance information of the object OBJ is acquired (FIG. 4 / STEP 10). A first specified number N1 of light-emitting elements L are sequentially switched from a non-emission state to an emission state in a specified order and at a specified cycle. The switching of the i-th light-emitting element L (i=q mod N1 (q=1, 2, . . . N1)) from an emission state to an emission non-emission state and the switching of the i+1-th light-emitting element L subsequent to the i-th light-emitting element L from an emission non-emission state to an emission state are performed simultaneously or almost simultaneously.

[0044] When one light receiving element S corresponding to one light emitting element L in an emitting state receives the pulsed reflected light, a signal corresponding to the reflected light is transmitted to the control device 100. Based on the signal, the control device 100 generates a distance image composed of a first specified number N1 of pixels corresponding to each of the first specified number N1 of light emitting elements L, with each pixel having the distance to the object OBJ as its pixel value.

[0045] In the third embodiment, as in the second embodiment, the filtering process (FIG. 4 / STEP 12) is omitted, and then effective and ineffective light-emitting elements are identified (FIG. 4 / STEP 14). The processing content of the third embodiment thereafter is the same as that of the first and second embodiments, and therefore further explanation is omitted.

[0046] In the above-described embodiment, the process of identifying effective and ineffective light-emitting elements (FIG. 4 / STEP 14) may be omitted. In the above-described embodiment, the process of calculating the sum ΣLI of the light-emitting intensities of the light-emitting elements L and, in turn, the process of comparing the sum ΣLI with a threshold value LI (FIG. 4 / STEP 18) may be omitted.

[0047] The magnitude relationship between the first specified number N1 and the second specified number N2 is determined, and depending on the determination result, any one of the light emission control processes of the first embodiment (N2<N1), the second embodiment (N1<N2), and the third embodiment (N1=N2) may be executed.

[0048] The control device 100 may identify the type of object OBJ and control the light-emitting intensity of the light-emitting elements L of the first specified number N1, particularly the light-emitting elements L among the effective light-emitting elements, that correspond to the object OBJ in different manners depending on the type of the object OBJ. For example, if the type of object OBJ is a traffic participant such as "another vehicle," "pedestrian," or "bicycle," the target light-emitting intensity may be set to be relatively higher (for example, by increasing γ) than if the type of object OBJ is a non-traffic participant such as a "road sign" or "building."

[0049] The type of the object OBJ can be identified based on the size and shape of a pixel area corresponding to the object OBJ that occupies the distance image. The optical device 1 may include an imaging device (not shown), and the type of the object OBJ may be identified by subjecting an image of the object OBJ acquired through the imaging device to image processing, pattern matching processing, etc.

[0050] 8 shows an optical device 1 according to another embodiment of the present invention, which includes a scanning unit 40. The other components of the optical device 1 are the same as those in the above embodiment, and therefore the same reference numerals are used to designate the same components, and detailed descriptions thereof will be omitted.

[0051] The scanning unit 40 has a function of scanning the light emitted from the light-emitting unit 10 by changing the irradiation angle of the light. Various scanning methods may be adopted, such as photonic crystals and liquid crystals. For example, the scanning unit 40 may include a rotating or moving mirror, such as a galvanometer scanner and / or a MEMS mirror, and may reflect the light on the mirror to scan the light. The mirror may be a flat mirror or a polyhedral mirror. The scanning unit 40 may include a driving device such as a motor, and may scan the light by displacing the light-emitting optical system 12 in the u1 direction and / or the v1 direction (see FIG. 2A ).

[0052] As in the third embodiment, the first designated number N1, which is the number of light-emitting elements L, is equal to the second designated number N2, which is the number of light-receiving elements S (n1=n2 and m1=m2).

[0053] The first specified number N1 of light-emitting elements L are sequentially switched from a non-emission state to an emission state in a specified order and at a specified cycle by the control device 100. The switching of the i-th light-emitting element L (i=q mod N1 (q=1, 2, . . . N1)) from the emission state to the emission non-emission state and the switching of the (i+1)-th light-emitting element L subsequent to the i-th light-emitting element L from the emission non-emission state to the emission state are executed simultaneously or almost simultaneously.

[0054] Furthermore, each time the light-emitting element L in the light-emitting state is switched, the operation of the scanning unit 40 is controlled and the direction of the scanning light is changed. For example, light is sequentially irradiated onto p (e.g., p = 4) different positions on the object OBJ, each corresponding to one light-receiving element S. Pulsed reflected light is received by each of the i light-receiving elements S corresponding to the i-th light-emitting element L in the light-emitting state, and a signal corresponding to the reflected light is transmitted to the control device 100. Based on the signal, the control device 100 generates a distance image having four times the number of light-emitting elements L (= first designated number N1) (= 4 × N1) of pixels, each pixel having the distance to the object OBJ as a pixel value. The subsequent light-emission control process is the same as in the second embodiment, and therefore will not be described again.

[0055] 1. Optical system 10. Light emitting unit 11. Light source 12. Light emitting optical system 20. Light receiving unit 21. Light receiving sensor 22. Light receiving optical system 100. Control device 110. Distance information acquisition unit 120. Contact determination unit L. Light emitting element S. Light receiving element V. Vehicle (moving device) HL. Headlight OBJ. Object.

Claims

1. An optical device comprising: a light-emitting unit having a plurality of light-emitting elements that emit light to be irradiated onto an object; a light-receiving unit having a plurality of light-receiving elements that receive the light reflected by the object and output a light-receiving signal; and a control device that acquires distance information about the object based on the light-receiving signals of each of the plurality of light-receiving elements, wherein the control device controls the light-emitting intensity of each of the plurality of light-emitting elements based on the distance information about the object so that the light-receiving intensity of each of the plurality of light-receiving elements is equal to or greater than a reference light-receiving intensity.

2. An optical device according to claim 1, wherein the control device controls the light emission intensity of each of the plurality of light-emitting elements based on distance information of the object so that the light reception intensity of each of the plurality of light-receiving elements is equal to or greater than a reference light reception intensity, and so that the sum of the light emission intensities of each of the plurality of light-emitting elements is equal to or less than a threshold value.

3. An optical device according to claim 1 or 2, wherein the control device controls the light emission intensity of some of the plurality of light-emitting elements corresponding to light-receiving elements having distance information where the distance to the object represented by the distance information is within a specified distance range, so as to be relatively lower than the light emission intensity of the other light-emitting elements.

4. An optical device according to claim 3, wherein the control device sets a range longer than a designated distance as the designated distance range and controls the light emission intensity of the part of the light-emitting elements to be relatively lower than the light emission intensity of the other light-emitting elements.

5. An optical device according to claim 1 or 2, wherein the control device identifies the type of the object and controls the light emission intensity of the light emitting element corresponding to the object among the plurality of light emitting elements in different manners depending on the type of the object.

6. An optical device according to claim 1, wherein the control device controls the light emission intensity of each of the plurality of light-emitting elements based on distance information about the object so that the light reception intensity of each of the plurality of light-receiving elements is equal to or greater than the reference light reception intensity, which is lower than the saturated light reception intensity.

7. An optical device according to claim 1, wherein the control device extracts distance information for each of the plurality of light-emitting elements from distance information corresponding to each of the plurality of light-receiving elements, the number of which is greater than the number of light-emitting elements, and controls the light-emitting intensity of each of the plurality of light-emitting elements based on the distance information for each of the plurality of light-emitting elements so that the light-receiving intensity of each of the plurality of light-receiving elements is equal to or greater than a reference light-receiving intensity.

8. An optical device according to claim 1 or 2, wherein the control device is configured to determine the possibility of contact between a mobile device on which the optical device is mounted and the object based on distance information about the object.

9. A moving device equipped with the optical device according to claim 8.

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