Detection device

Abstract

A detection device (1) is provided with: a light-emitting device (20) including a plurality of light-emitting elements (21) that emit identifiable specific light into a detection area (100); and a light-receiving device (30) that receives the specific light emitted from the light-emitting device (20). The light-receiving device (30) includes a light-receiving sensor (31). The light-receiving sensor (31) outputs, each time a change in brightness is detected for each pixel, an event signal including a detection time at which the change in brightness is detected and a pixel position at which the change in brightness is detected. The detection device (1) is further provided with a detection unit (11) that detects an object in the detection area (100) using the event signal if a change in brightness has occurred in a pixel corresponding to the specific light received by the light-receiving device (30).

Description

Detection device

[0001] The present invention relates to a detection device for detecting an object in a detection area.

[0002] There are known detection devices that detect objects that have entered a restricted area. For example, some detection devices use a beam switch, and the beam is known to be infrared or ultrasonic. There are also known detection devices that detect an intruding object by photographing the restricted area and processing the photographed image.

[0003] Patent Document 1 describes an intrusion monitoring device that detects objects by arranging a light-emitting device and a CCD camera opposite each other. More specifically, Patent Document 1 describes an intrusion monitoring device that detects the intrusion of an object by capturing an image including a light-emitting device with a CCD camera, narrowing the captured image to a window of a predetermined size that includes the light-emitting device, and comparing the brightness of the image within the window with an average value for each predetermined time period.

[0004] Japanese Patent Publication No. 10-234031

[0005] However, the above-mentioned conventional techniques have the following problems. For example, when using a beam switch, the optical axes of the beam switches must be aligned, which makes installation time-consuming. In particular, the greater the distance between the light emitter and the light receiver, the more difficult it becomes to align the optical axes.

[0006] Furthermore, when performing image processing such as that described in Patent Document 1, the processing load becomes heavy.

[0007] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to realize a detection device that is easy to install and has a light processing load.

[0008] In order to solve the above-mentioned problems, a detection device according to one aspect of the present invention is a detection device that detects an object in a detection area, and includes: a light emitter that includes a plurality of light emitting elements that emit identifiable specific light in the detection area; and a light receiver that receives the specific light emitted from the light emitter, wherein the light receiver includes an event-based sensor that outputs an event signal that includes the detection time at which a luminance change is detected for each pixel and the pixel position at which the luminance change is detected, and further includes a detection unit that detects an object in the detection area using the event signal when the luminance change occurs in the pixel corresponding to the specific light received by the light receiver.

[0009] According to one aspect of the present invention, an event-based sensor is used as the optical receiver, so that the optical receiver can receive the light emitted from the light-emitting element without aligning the axis of the light emitted from the light-emitting element with the optical receiver. When the specific light emitted from the light-emitting element is blocked by an object that has entered the detection area or is moving within the detection area, the event is detected by the event-based sensor, and the object in the detection area is detected by the detection unit. Therefore, a detection device that detects objects in the detection area can be realized without requiring time-consuming installation such as aligning the optical axis.

[0010] FIG. 1 is a functional block diagram showing the main configuration of a detection device according to an embodiment of the present invention. FIG. 2 is a diagram for explaining an example of detection by the detection device. FIG. 3 is a diagram showing an example of the arrangement of a light emitter and a light receiver included in the detection device. FIG. 4 is a diagram showing another example of the arrangement of a light emitter and a light receiver included in the detection device. FIG. 5 is a diagram showing yet another example of the arrangement of a light emitter and a light receiver included in the detection device. FIG. 6 is a diagram showing another example of a light receiver included in the detection device. FIG. 7 is a diagram showing a light emitting / receiving device including a light emitter and a light receiver. FIG. 8 is a diagram showing an example of the arrangement of the light emitting / receiving device. FIG. 9 is a diagram for explaining an example of a modulation pattern of a light emitting element. FIG. 10 is a diagram showing an example where a light emitter and a light receiver are arranged facing each other on the sea. FIG. 11 is a diagram showing an example where a lighting device, which is a light emitting device other than a light emitter, is present within the light receiving range of the light receiver.

[0011] [Outline of the Detection Device] An embodiment of the present invention will be described in detail below. The detection device 1 according to this embodiment detects objects in a detection area 100. The objects in the detection area 100 include objects that have entered the detection area 100, objects that move within the detection area 100, and the like.

[0012] The detection device 1 is a detection device that uses a so-called beam switch. The detection device 1 uses an event-based sensor as a sensor for receiving light, eliminating the need for optical axis alignment between the light emitter and the light receiver, which was previously required. This allows for a detection device that is easy to install and does not impose a heavy load on the detection process.

[0013] [Details of the Detection Device] Fig. 1 is a functional block diagram showing the configuration of the main parts of the detection device 1. As shown in Fig. 1, the detection device 1 includes a control unit 10, a light emitter 20, and a light receiver 30. The control unit 10 includes a detection unit 11 and a light-emitting element setting unit 12.

[0014] The detection unit 11 detects the presence or absence of an object in the detection area 100. The detection method performed by the detection unit 11 will be described in detail later.

[0015] The light emitting element setting unit 12 sets a modulation pattern for the light emitted from the light emitting element 21 of the light emitter 20. The modulation pattern includes changes in amplitude (intensity), wavelength, phase, and emission pattern (on and off timing).

[0016] The light-emitting element setting unit 12 sets the modulation pattern of the light emitted from the light-emitting element 21, so that the detection unit 11 can recognize whether the light received by the light receiver 30 is emitted from the light-emitting element 21 or not.

[0017] The light-emitting element setting unit 12 may be included in the light-receiver 30. When the light-receiver 30 includes the light-emitting element setting unit 12, the light-receiver 30 may directly transmit the modulation pattern set by the light-emitting element setting unit 12 to the light-emitting element 20. This transmission may be wireless or wired.

[0018] Furthermore, the light-emitting element setting unit 12 may change the preset modulation pattern. This change may be made when light having the same or similar modulation pattern as the preset modulation pattern is received from a source other than the light-emitting device 20. This makes it possible to prevent the light that is not emitted from the light-emitting device 20 from being mistakenly determined to be emitted from the light-emitting device 20. This improves the reliability of detection by the detection device 1.

[0019] The light emitter 20 includes a plurality of light emitting elements 21. The light emitting elements 21 emit modulated light, which is light modulated according to the modulation pattern set by the light emitting element setting unit 12. The modulated light is light emitted from the light emitting elements 21, and therefore can be said to be specific light that can be identified.

[0020] The light receiver 30 is an imaging device that captures an image of an area including the light emitter 20 and the detection area 100 (see FIG. 2 ), and includes a light receiving sensor 31. The light receiving sensor 31 is an event-based sensor that detects a change in luminance of each pixel in the imaging device as an event, and outputs an event signal that includes the detection time when the event was detected, the pixel position where the event occurred, and the change in pixel value each time the event is detected.

[0021] Using an event-based sensor as the light-receiving sensor 31 provides the following advantages over conventional image sensors, such as a charge-coupled device (CCD) image sensor or a complementary metal-oxide-semiconductor (CMOS) image sensor. In this embodiment, modulated light is emitted from the light-emitting element 21. Capturing the modulated light using the conventional image sensor requires a high sampling rate, resulting in a heavy processing load. The light-receiving sensor 31 of this embodiment uses an event-based sensor, which does not require a high sampling rate and allows the detection device 1 to be realized with a low processing load. To detect objects moving at high speed within the detection area 100, it is desirable to use high-frequency modulated light, but capturing such light using conventional image sensors is difficult. The light-receiving sensor 31 of this embodiment uses an event-based sensor, which allows it to detect events even with high-frequency modulated light. Therefore, it is possible to detect objects moving at high speed within the detection area 100.

[0022] Therefore, it can be said that the light receiving sensor 31 outputs an event signal including the detection time when a luminance change was detected for each pixel and the pixel position where the luminance change was detected, every time a luminance change is detected.

[0023] By using an event-based sensor as the light-receiving sensor 31, the light emitted from the light emitter 20 can be received by the light receiver 30 without aligning the optical axes of the light emitter 20 and the light receiver 30, as long as the light emitter 20 is included in the imaging range of the light receiver 30. If the light receiver 30 can receive the light, it can detect changes in the luminance of the light emitted from the light emitter 20. Therefore, there is no need to align the optical axes of the light emitter 20 and the light receiver 30.

[0024] [Details of Detection Process] Next, with reference to FIG. 2 , an example of detecting an object in a detection area 100 using the detection device 1 will be described. FIG. 2 is a diagram for explaining an example of detection by the detection device 1. In the example shown in FIG. 2 , the light emitter 20 and the light receiver 30 are arranged facing each other. Here, facing each other means that the light receiver 30 is arranged in the direction of light emission from the light emitter 20. The light emitter 20 includes five light emitting elements 21, light emitting elements 21A to 21E. The light emitting elements 21A to 21E are arranged in a straight line and all emit light in the same direction. In this case, the detection area 100 is the range through which light emitted from each of the five light emitting elements 21 and received by the light receiver 30 passes. Therefore, when a desired area is to be the detection area, the light emitter 20 and the light receiver 30 can be arranged so that light emitted from the light emitter 20 and passing through the area can be received by the light receiver 30.

[0025] In addition, in the light-emitting elements 21 arranged in a straight line, the modulation pattern of the light emitted from the light-emitting elements (21A, 21E) arranged at both ends may be different from the modulation pattern of the light emitted from the light-emitting elements (21B to 21D) arranged other than at both ends.

[0026] The light emitted from both ends of the light-emitting elements 21 arranged in a straight line indicates the edges of the detection area 100. Therefore, if the modulation pattern of the light emitted from the light-emitting elements (21A, 21E) at both ends is made different from that of the other light-emitting elements 21, the edges of the detection area 100 will emit light with a different modulation pattern from the others, making it easy to identify the edges of the detection area 100.

[0027] Furthermore, in the light-emitting elements 21 arranged in a line, the modulation pattern of the light emitted from the light-emitting element 21A arranged at one end, the modulation pattern of the light emitted from the light-emitting element 21E arranged at the other end, and the modulation pattern of the light emitted from the light-emitting elements (21B to 21D) arranged other than the two ends may be different, thereby making it easy to identify one end and the other end of the detection area 100.

[0028] When an object enters the detection area 100, the object blocks the light emitted from the light-emitting element 21. As a result, the light-receiving sensor 31 of the light receiver 30 detects a change in brightness at the pixel corresponding to the position of the object, and an event signal is output.

[0029] When the detection unit 11 receives an event signal, it detects an object in the detection area 100 using the change in brightness indicated by the event signal, the position of the pixel, and the modulation pattern of the light received by the pixel. More specifically, the detection unit 11 recognizes from the light modulation pattern and the position of the pixel that the light whose brightness has changed is emitted from a specific light-emitting element 21 of the light emitter 20, and when the light emitted from this specific light-emitting element 21 is blocked by an object or the like and the brightness changes, it detects the presence of an object in the detection area 100, i.e., that an object has entered the detection area 100. On the other hand, even if natural light different from the light emitted from the light emitter 20 is blocked by trees or the like and a brightness change is detected by the light receiver 30, the presence of an object in the detection area 100 will not be detected.

[0030] The change in brightness that occurs in the light-receiving sensor 31 used by the detection unit 11 to detect an object is not a change in brightness due to modulation of the modulated light, but a change in brightness that occurs when the modulated light is blocked by an object. Even if a change in brightness due to modulation of the modulated light occurs in the light-receiving sensor 31, the detection unit 11 will not detect the presence of an object in the detection area 100.

[0031] The detection unit 11 may detect whether an object has entered the detection area 100 by comparing the amount of change in brightness with a threshold value, or may detect whether an object has entered the detection area 100 based on whether the brightness has decreased, i.e., whether it has become darker.

[0032] As described above, the detection device 1 detects an object in the detection area 100. The detection device 1 includes, in the detection area 100, a light emitter 20 including a plurality of light emitting elements 21 that emit identifiable specific light, and a light receiver 30 that receives the specific light emitted by the light emitter 20. The light receiver 30 includes a light receiving sensor 31 that is an event-based sensor, and the light receiving sensor 31 outputs an event signal including the detection time when a luminance change is detected for each pixel and the pixel position where the luminance change is detected. The detection device 1 further includes a detection unit 11 that detects an object in the detection area 100 using the event signal when a luminance change occurs in a pixel corresponding to the specific light received by the light receiver 30.

[0033] In this way, the detection device 1 uses the light receiving sensor 31, which is an event-based sensor, for the light receiver 30. Therefore, the light emitted from the light emitting element 21 can be received by the light receiver 30 without aligning the axis of the light emitted from the light emitting element 21 with the light receiver 30. When the specific light emitted from the light emitting element 21 is blocked by an object that has entered the detection area 100 or an object that is moving within the detection area 100, the light receiving sensor 31 detects the event, and the detection unit 11 detects the object in the detection area 100. This makes it possible to realize a detection device 1 that detects objects in the detection area 100 without requiring time-consuming installation such as aligning the optical axis.

[0034] [Example 1 of Arrangement of Light Emitter and Light Receiver] Next, an example of arrangement of the light emitter 20 and the light receiver 30 will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of arrangement of the light emitter 20 and the light receiver 30.

[0035] In the example shown in FIG. 3, the detection device 1 includes a light emitter 20A (first light emitter), a light emitter 20B (second light emitter), a light receiver 30A (first light receiver), and a light receiver 30B (second light receiver).

[0036] The light emitter 20A includes a plurality of light-emitting elements 21 arranged in a straight line, with the light receiver 30B located at one end of the line. The light emitter 20B also includes a plurality of light-emitting elements 21 arranged in a straight line, with the light receiver 30A located at one end of the line. The light emitter 20A and the light receiver 30B are arranged opposite the light emitter 20B and the light receiver 30A. That is, the light emitter 20A and the light receiver 30A are arranged opposite each other, and the light emitter 20B and the light receiver 30B are arranged opposite each other. In other words, the light receiver 30A is arranged at an oblique angle to the light receiver 30B.

[0037] The light receiver 30A receives the light emitted from the light emitter 20A, and the light receiver 30B receives the light emitted from the light emitter 20B. In other words, the light emission range of the light emitter 20A includes the light receiver 30A, and the light emission range of the light emitter 20B includes the light receiver 30B. Furthermore, the light receiver 30A includes the light emitter 20A, and the light receiver 30B includes the light emitter 20B.

[0038] As a result, the combined area of ​​detection area 100A, which is the area through which light emitted from light emitter 20A and received by light receiver 30A passes, and detection area 100B, which is the area through which light emitted from light emitter 20B and received by light receiver 30BA passes, can be used as detection area 100. Therefore, compared to when one light emitter 20 and one light receiver 30 are arranged opposite each other, detection area 100 can be made larger.

[0039] [Example 2 of Arrangement of Light Emitter and Light Receiver] Next, another example of arrangement of the light emitter 20 and the light receiver 30 will be described with reference to Fig. 4. Fig. 4 is a diagram showing another example of arrangement of the light emitter 20 and the light receiver 30.

[0040] In the example shown in Figure 4, the detection device 1 includes a light emitter 20C (first light emitter), a light emitter 20E (second light emitter), a light receiver 30C (first light receiver), a light receiver 30D (first light receiver), a light receiver 30E (second light receiver), and a light receiver 30F (second light receiver).

[0041] Light emitter 20C includes a plurality of light-emitting elements 21 arranged in a straight line, with light receiver 30E arranged at one end of the line and light receiver 30F arranged at the other end. Light emitter 20E also includes a plurality of light-emitting elements 21 arranged in a straight line, with light receiver 30C arranged at one end of the line and light receiver 30D arranged at the other end.

[0042] The light emitter 20C, the light receiver 30E, and the light receiver 30F are arranged opposite the light emitter 20E, the light receiver 30C, and the light receiver 30D. That is, the light emitter 20C and the light receiver 30C and the light receiver 30D are arranged opposite each other, and the light emitter 20E and the light receiver 30E and the light receiver 30F are arranged opposite each other.

[0043] Light receivers 30E and 30F receive light emitted from light emitter 20E, and light receivers 30C and 30D receive light emitted from light emitter 2CB. That is, the light emission range of light emitter 20E includes light receivers 30E and 30F, and the light emission range of light emitter 20C includes light receivers 30C and 30D. Furthermore, the light reception ranges of light receivers 30E and 30F include light emitter 20E, and the light reception ranges of light receivers 30C and 30D include light emitter 20C.

[0044] As a result, the combined area of ​​detection area 100C, detection area 100D, detection area 100E, and detection area 100F can be defined as detection area 100. Therefore, the area between light emitter 20C and light emitter 20D can be defined as detection area 100 without any omissions. In other words, the reliability of detection can be improved.

[0045] Here, detection area 100C is a passage area for light emitted from light emitter 20C and received by light receiver 30C. Detection area 100D is a passage area for light emitted from light emitter 20C and received by light receiver 30D. Detection area 100E is a passage area for light emitted from light emitter 20E and received by light receiver 30E. Detection area 100F is a passage area for light emitted from light emitter 20E and received by light receiver 30F.

[0046] [Example 3 of Arrangement of Light Emitter and Light Receiver] Next, still another example of arrangement of the light emitter 20 and the light receiver 30 will be described with reference to Fig. 5. Fig. 5 is a diagram showing still another example of arrangement of the light emitter 20 and the light receiver 30.

[0047] 5, the light emitter 20 and the light receiver 30 are disposed adjacent to each other. A reflector 40 is disposed to reflect the light emitted from the light emitter 20. In other words, the reflector 40 is disposed at a position that is included in the light emission range of the light emitter 20 and the light reception range of the light receiver 30.

[0048] As a result, the light emitted from the light emitter 20 is reflected by the reflector 40 and received by the light receiver 30. Therefore, the area through which the light emitted from the light emitter 20 passes before being reflected by the reflector 40, and the area through which the light reflected by the reflector 40 passes before being received by the light receiver 30, form the detection area 100.

[0049] According to the above configuration, the light emitter 20 and the light receiver 30 can be disposed in approximately the same position, which makes it easier to wire the power supply and other necessary components for the light emitter 20 and the light receiver 30.

[0050] [Another Example of Light Receiver] Next, another example of the light receiver 30 will be described with reference to Fig. 6. Fig. 6 is a diagram showing another example of the light receiver 30. The light receiver 30X shown in Fig. 6 can receive light not from one direction but from all directions of 360 degrees. In the example shown in Fig. 6, a structure is shown in which light coming from all directions of 360 degrees is reflected by a mirror 32 and reaches the light receiving sensor 31.

[0051] By using the light receiver 30X, the position of the light emitter 20 can be placed without being limited. For example, as shown in Fig. 6, light emitted from the light emitter 20X and the light emitter 20Y, which are placed in opposite directions by 180 degrees as viewed from the light receiver 30X, can be received by a single light receiver 30X. In other words, the light-emitting range of the light emitter 20X and the light emitter 20Y include the light receiver 30X. Furthermore, the light emitter 20X and the light emitter 20Y are included in the light-receiving range of the light receiver 30X.

[0052] In this case, the area through which light emitted from light emitter 20X and received by light receiver 30X passes is detection area 100X, and the area through which light emitted from light emitter 20Y and received by light receiver 30X passes is detection area 100Y.

[0053] [Example 4 of Arrangement of Light Emitter and Light Receiver] Next, with reference to Figures 7 and 8, an example of arrangement when using a light emitter with a light emission range of 360 degrees and a light receiver with a light reception range of 360 degrees will be described. Figure 7 shows a light emitting / receiving device 50 including a light emitter 20Z and light receivers (30X, 30Y). Light emitter 20Z is a light emitter with a light emission range of 360 degrees, and light receivers 30X and 30Y are light receivers with light reception ranges of 360 degrees.

[0054] 7 includes a light emitter 20Z including a plurality of light emitting elements 21Z arranged in a straight line and having a light emitting range of 360 degrees, a light receiver 30X arranged at one end of the straight line, and a light receiver 30Y arranged at the other end. Here, the straight line along which the plurality of light emitting elements 21Z are arranged is defined as the Z direction, and directions perpendicular to each other on a plane perpendicular to the Z direction are defined as the X direction and the Y direction.

[0055] Although Figure 7 shows a configuration in which light receivers (30X, 30Y) are arranged at both ends of the light emitting element 21Z arranged in a straight line, the light receiver 30 may be arranged at only one end.

[0056] Fig. 8 shows an example of the arrangement of the light-emitting and receiving devices 50. Reference numeral 801 in Fig. 8 shows the arrangement of the light-emitting and receiving devices 50 as viewed from above in the vertical direction, in other words, from the +Z direction. That is, it shows the state in which the light-emitting and receiving devices 50 are viewed from the light receiver 30X side. Reference numeral 801 in Fig. 8 shows the state in which four light-emitting and receiving devices 50 are arranged at the four corners of a rectangle as viewed from above in the vertical direction.

[0057] If a plurality of light-emitting and light-receiving devices 50 are configured so that light emitted from one light-emitting and light-receiving device 50 is received by another light-emitting and light-receiving device 50, the area between the light-emitting and light-receiving devices 50 can be used as a detection area 100.

[0058] Therefore, when four light-emitting and light-receiving devices 50 are arranged at the four corners of a rectangle as shown in 801 in Figure 8, the area between the light-emitting and light-receiving devices 50, i.e., the area corresponding to the sides of the rectangle, can be used as the detection area 100.

[0059] 8 , by arranging the light emitting and receiving devices 50 at the four corners of the rectangular area 101, the areas corresponding to the sides of the rectangular area 101, i.e., the area formed by the sides of the rectangular area 101 and the height of the light emitting and receiving devices 50, can be used as the detection area 100. Therefore, an object entering the rectangular area 101 can be detected at the sides of the rectangular area 101.

[0060] Furthermore, in a detection device using a conventional beam switch, when the light emitter and light receiver are arranged as shown in 801 in Fig. 8, it is necessary to arrange a set of light emitter and light receiver for each side of the rectangular area 101, which is time-consuming. By using the light-emitting / light-receiving device 50, this time-consuming process can be eliminated.

[0061] Furthermore, when it is desired to detect an area at a distance, this can be achieved by arranging the light-emitting and light-receiving devices 50 in a straight line, as shown in 802 in Fig. 8. In this case, simply by arranging the light-emitting and light-receiving devices 50 in a straight line, the space between the light-emitting and light-receiving devices 50 can be made into the detection area 100.

[0062] In a detection device using a conventional beam switch, when the light emitter and light receiver are arranged as shown in 802 in Fig. 8, it is necessary to arrange a set of light emitter and light receiver for each detection area, which is time-consuming. By using the light-emitting / light-receiving device 50, this time-consuming process can be eliminated.

[0063] [Example of modulation pattern of light-emitting element] Next, an example of a modulation pattern of the light-emitting element 21 will be described with reference to Fig. 9. Fig. 9 is a diagram for explaining an example of a modulation pattern of the light-emitting element 21. Fig. 9 shows an example in which the light emitter 20 includes 15 light-emitting elements 21. Here, these elements are designated as light-emitting elements 21X1 to 21X5, light-emitting elements 21Y1 to 21Y5, and light-emitting elements 21Z1 to 21Z5, respectively.

[0064] As an example, the light-emitting elements 21 may be divided into a plurality of groups, and each group may emit light with a different modulation pattern. For example, 15 light-emitting elements 21 may be divided into three groups, light-emitting elements 21X, light-emitting elements 21Y, and light-emitting elements 21Z, and light-emitting elements 21X, light-emitting elements 21Y, and light-emitting elements 21Z may emit light with different modulation patterns. Note that light-emitting elements 21X include light-emitting elements 21X1 to 21X5. Light-emitting element 21Y includes light-emitting elements 21Y1 to 21Y5. Light-emitting element 21Z includes light-emitting elements 21Z1 to 21Z5.

[0065] If light-emitting element 21X emits light of modulation pattern A, light-emitting element 21Y emits light of modulation pattern B, and light-emitting element 21Z emits light of modulation pattern C, then when light-receiver 30 receives light of modulation pattern A, it can recognize that the light is emitted from light-emitting element 21X. Also, when light of modulation pattern B is received, it can recognize that the light is emitted from light-emitting element 21Y. Furthermore, when light of modulation pattern C is received, it can recognize that the light is emitted from light-emitting element 21Z.

[0066] As another example, light-emitting elements 21X1, 21Y1, and 21Z1 may be grouped together, light-emitting elements 21X2, 21Y2, and 21Z2 may be grouped together, light-emitting elements 21X3, 21Y3, and 21Z3 may be grouped together, light-emitting elements 21X4, 21Y4, and 21Z4 may be grouped together, and light-emitting elements 21X5, 21Y5, and 21Z5 may be grouped together, and each group may emit light using a different modulation pattern.

[0067] If the resolution of the light receiving sensor 31 of the light receiver 30 is not sufficient to distinguish all of the light emitting elements 21 of the light emitter 20 due to the distance between the light emitter 20 and the light receiver 30 being large, the light receiver 30 will not be able to grasp the exact position of each light emitting element 21.

[0068] Even in such a case, if light with a different modulation pattern is emitted for each group, it is possible to distinguish between the modulation patterns, and therefore it is possible to distinguish between the groups of light-emitting elements 21. Therefore, even if the resolution of the light-receiving sensor 31 is not sufficient to distinguish between all of the light-emitting elements 21, it is possible for the light-receiver 30 to distinguish between the light-emitting elements 21.

[0069] Furthermore, the light may be emitted at different light emission timings for each group. As with the case where the modulation patterns are different, even when the light-emitting sensor 31 does not have a sufficient resolution to distinguish all of the light-emitting elements 21, the light-receiving device 30 can still distinguish the light-emitting elements 21 when the light-emitting timings are different for each group.

[0070] [Example of Detection Area] The detection device 1 according to this embodiment can function even on coastal or offshore facilities, etc. For example, if the light emitter 20 and the light receiver 30 are arranged facing each other on the sea as shown in Fig. 10 , the area through which the light emitted from the light emitter 20 passes and is received by the light receiver 30 becomes the detection area 100, as described above.

[0071] When the light emitter 20 and the light receiver 30 are placed on the sea, the relative positions of the light emitter 20 and the light receiver 30 change over time due to the influence of waves. However, as long as the light emitter 20 is within the light receiving range of the light receiver 30, the light receiver 30 can detect changes in the brightness of the light emitted from the light emitter 20. Therefore, detection is possible even if the location where the light emitter 20 and the light receiver 30 are installed, such as on the sea or on the coast, is unstable.

[0072] Furthermore, the configuration may be such that an object detected within the detection area 100 can be tracked. The detected object can be tracked by tracking the position of the pixel of the light receiving sensor 31 where the event occurred.

[0073] Furthermore, by arranging the light emitting elements 21 of the light emitter 20 in a matrix rather than in a straight line, a wider area can be made the detection area 100 .

[0074] [Modification] Furthermore, the detection device 1 may also use the detection area 100 as an area through which light from a light-emitting device other than the light emitter 20 passes when the light receiver 30 receives the light.

[0075] Naturally, the light receiver 30 also receives light emitted from sources other than the light emitter 20, as long as the light is present within the light receiving range. Therefore, any change in the luminance of the light can be detected. Therefore, for example, as shown in Fig. 11, if lighting devices 121 and 122, which are light-emitting devices other than the light emitter 20, are present within the light receiving range 110 of the light receiver 30, the change in luminance of the light emitted from the lighting devices 121 and 122 can be detected.

[0076] This enables the detection device 1 to detect abnormalities such as failures of the lighting devices 121 and 122, and to detect light blocking by some object between the lighting devices 121 and 122 and the light receiver 30, etc.

[0077] [Example of implementation using software] The functions of the detection device 1 (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device (particularly each part included in the control unit 10).

[0078] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using the control device and storage device.

[0079] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0080] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0081] Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0082] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0083] [Summary] A detection device according to aspect 1 of the present invention is a detection device that detects an object in a detection area, and includes: a light emitter including a plurality of light emitting elements that emit identifiable specific light in the detection area; and a light receiver that receives the specific light emitted from the light emitter, wherein the light receiver includes an event-based sensor that outputs an event signal including a detection time when a luminance change is detected for each pixel and a pixel position at which the luminance change is detected, and further includes a detection unit that detects an object in the detection area using the event signal when the luminance change occurs in the pixel corresponding to the specific light received by the light receiver.

[0084] According to the above configuration, since an event-based sensor is used for the light receiver, the light emitted from the light-emitting element can be received by the light receiver without aligning the axis of the light emitted from the light-emitting element with the light receiver. When the specific light emitted from the light-emitting element is blocked by an object that has entered the detection area or an object moving within the detection area, the event is detected by the event-based sensor, and the object in the detection area is detected by the detection unit.

[0085] Therefore, it is possible to realize a detection device that detects an object in a detection area without requiring time-consuming work such as aligning the optical axis.

[0086] According to a second aspect of the present invention, in the detection device of the first aspect, the specific light is modulated light. With this configuration, it is possible to easily identify whether the specific light is light emitted from a light-emitting element.

[0087] A detection device according to aspect 3 of the present invention is the same as that according to aspect 1 or 2, wherein the light-emitting elements are arranged in a straight line, and the modulation pattern of the light emitted from the light-emitting elements arranged at both ends of the straight line is different from the modulation pattern of the light emitted from the light-emitting elements arranged other than at both ends of the straight line.

[0088] The light emitted from both ends of the linearly arranged light-emitting elements indicates the edge of the detection area. With this configuration, the edge of the detection area is easily identified because light with a different modulation pattern is emitted from the edge of the detection area.

[0089] A detection device according to aspect 4 of the present invention is the same as that according to aspect 2, wherein the light-emitting elements are arranged in a straight line, and the modulation pattern of the light emitted from the light-emitting element arranged at one end of the straight line, the modulation pattern of the light emitted from the light-emitting element arranged at the other end of the straight line, and the modulation pattern of the light emitted from the light-emitting element arranged at a position other than both ends of the straight line are different.

[0090] The light emitted from both ends of the linearly arranged light-emitting elements indicates the edges of the detection area. With this configuration, each edge of the detection area emits light with a different modulation pattern, making it easy to identify each edge of the detection area.

[0091] A detection device according to aspect 5 of the present invention is, in any one of aspects 1 to 4, provided with a plurality of the light emitters and the light receivers, wherein light emitted from a first light emitter, which is one of the plurality of light emitters, is received by a first light receiver, which is one of the plurality of light receivers, and light emitted from a second light emitter, which is another one of the plurality of light emitters, is received by a second light receiver, which is another one of the plurality of light receivers, wherein the plurality of light-emitting elements included in the first light emitter are arranged in a straight line, and the second light receiver is arranged at one end of the straight line, and the plurality of light-emitting elements included in the second light emitter are arranged in a straight line, and the first light receiver is arranged at a position at one end of the straight line that is diagonal to the second light receiver.

[0092] According to the above configuration, the entire area between the first light emitter and the second light emitter can be used as the detection area.

[0093] A detection device according to aspect 6 of the present invention is, in any of aspects 1 to 4, provided with a plurality of the light emitters and the light receivers, wherein light emitted from a first light emitter that is one of the plurality of light emitters is received by a first light receiver that is one of the plurality of light receivers, light emitted from a second light emitter that is another one of the plurality of light emitters is received by a second light receiver that is another one of the plurality of light receivers, wherein the plurality of light-emitting elements included in the first light emitter that is one of the plurality of light emitters are arranged in a straight line, and two of the plurality of light receivers are arranged at both ends of the straight line, and the plurality of light-emitting elements included in the second light emitter that is another one of the plurality of light emitters are arranged in a straight line, and the other two of the plurality of light receivers are arranged at both ends of the straight line.

[0094] According to the above configuration, the entire region between the first light emitter and the second light emitter is used as the detection area, and the reliability of detection can be increased.

[0095] In the detection device of aspect 7 of the present invention, in any of aspects 1 to 6, the light emitter and the light receiver are arranged in close proximity to each other, and the light receiver receives light emitted from the light emitter that is reflected by a reflecting portion arranged on the outer periphery of the detection area.

[0096] According to the above configuration, the light emitter and the light receiver can be disposed in substantially the same position to realize a detection device, which simplifies wiring for the power supply and the like required for the light emitter and the light receiver.

[0097] A detection device according to an eighth aspect of the present invention is the detection device of any one of the first to seventh aspects, wherein the light receiver has a light receiving range of 360 degrees.

[0098] According to the above configuration, a detection area that would conventionally require multiple light receivers can be handled with a single light receiver.

[0099] A detection device according to a ninth aspect of the present invention is the detection device of any one of the first to eighth aspects, wherein the light emitter has a light emission range of 360 degrees.

[0100] According to the above configuration, a detection area that would conventionally require multiple light emitters can be handled with a single light emitter.

[0101] A detection device according to aspect 10 of the present invention is one in which, in any one of aspects 1 to 9, the plurality of light-emitting elements included in the light emitter are divided into a plurality of groups, and the light emitter emits light with a different modulation pattern for each of the groups.

[0102] According to the above configuration, the modulation patterns of the light-emitting elements are different for each group, so that even if the light-emitting element and the light-receiver are far enough apart that the resolution of the event-based sensor cannot distinguish between the light-emitting elements, the light-emitting elements can be distinguished for each group.

[0103] A detection device according to an eleventh aspect of the present invention is the detection device of any one of the first to ninth aspects, wherein the light emitter emits light at different light emission timings of the light emitting elements for each of the groups.

[0104] According to the above configuration, the light emission timing of the light-emitting elements differs for each group, so that even if the light emitter and the light receiver are far enough apart that the resolution of the event-based sensor cannot distinguish between the light-emitting elements, the light-emitting elements can be distinguished for each group.

[0105] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0106] 1 Detection device 10 Control unit 11 Detection unit 12 Light-emitting element setting unit 20, 20A to 20D, 20X, 20Y, 20Z Light emitter 21, 21A to 21E Light-emitting element 30, 30A to 30F, 30X, 30Y Light receiver 31 Light-receiving sensor (event-based sensor) 32 Mirror 40 Reflection unit 100 Detection area 110 Light-receiving range 121, 122 Illumination device

Claims

1. A detection device for detecting an object in a detection area, comprising: a light emitter including a plurality of light emitting elements that emit identifiable specific light in the detection area; and a light receiver that receives the specific light emitted from the light emitter, wherein the light receiver includes an event-based sensor, and the event-based sensor outputs an event signal including a detection time at which a luminance change is detected for each pixel and a pixel position at which the luminance change is detected every time the luminance change is detected, and when the luminance change occurs in the pixel corresponding to the specific light received by the light receiver, the detection device further includes a detection unit that detects an object in the detection area using the event signal.

2. The detection device according to claim 1, wherein the specific light is modulated light.

3. The detection device according to claim 2, wherein the light emitting elements are arranged in a straight line, and a modulation pattern of light emitted from the light emitting elements arranged at both ends of the straight line is different from a modulation pattern of light emitted from the light emitting elements arranged other than both ends of the straight line.

4. The detection device according to claim 2 or 3, wherein the light emitting elements are arranged in a straight line, and a modulation pattern of light emitted from the light emitting element arranged at one end of the straight line, a modulation pattern of light emitted from the light emitting element arranged at the other end of the straight line, and a modulation pattern of light emitted from the light emitting elements arranged other than both ends of the straight line are different.

5. The detection device according to any one of claims 1 to 4, comprising a plurality of the light emitters and a plurality of the light receivers, light emitted from a first light emitter which is one of the plurality of light emitters is received by a first light receiver which is one of the plurality of light receivers, light emitted from a second light emitter which is another one of the plurality of light emitters is received by a second light receiver which is another one of the plurality of light receivers, the plurality of light emitting elements included in the first light emitter are arranged in a straight line, the second light receiver is arranged at one end of the straight line, the plurality of light emitting elements included in the second light emitter are arranged in a straight line, and the first light receiver is arranged at a position that is obliquely intersecting with the second light receiver among one end of the straight line.

6. The detection device according to any one of claims 1 to 5, comprising a plurality of the light emitters and a plurality of the light receivers, wherein light emitted from a first light emitter, which is one of the plurality of light emitters, is received by a first light receiver, which is one of the plurality of light receivers; light emitted from a second light emitter, which is another one of the plurality of light emitters, is received by a second light receiver, which is another one of the plurality of light receivers; a plurality of the light emitting elements included in the first light emitter, which is one of the plurality of light emitters, are arranged in a straight line, and two of the plurality of light receivers are arranged at both ends of the straight line; and a plurality of the light emitting elements included in the second light emitter, which is another one of the plurality of light emitters, are arranged in a straight line, and another two of the plurality of light receivers are arranged at both ends of the straight line.

7. The detection device according to any one of claims 1 to 6, wherein the light emitter and the light receiver are arranged in the vicinity of each other, and the light receiver receives light emitted from the light emitter and reflected by a reflection portion arranged on the outer periphery of the detection area.

8. The detection device according to any one of claims 1 to 7, wherein the light receiver has a light receiving range of 360 degrees.

9. The detection device according to claim 8, wherein the light emitter has a light emitting range of 360 degrees.

10. The detection device according to claim 2, wherein the plurality of the light emitting elements included in the light emitter are divided into a plurality of groups, and the light emitter emits light with different modulation patterns for each group.

11. The detection device according to claim 10, wherein the light emitter emits light with different light emission timings for each group.

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