Position detection device

Abstract

A position detection device (1) is provided with: a first light-emitting device (110); a second light-emitting device (120); a first light-receiving device (210) that receives light emitted from the first light-emitting device (110); a second light-receiving device (220) that receives light emitted from the second light-emitting device (120); and a position detection unit (11) that detects the position of an object in a detection area (100) using the position of a pixel at which a change in brightness is detected in the first light-receiving device (210) and the position of a pixel at which a change in brightness is detected in the second light-receiving device (220).

Description

Position detection device

[0001] The present invention relates to a position detection device that detects the position of 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] Although such a detection device can detect that an object has entered a restricted area, it cannot recognize where within the restricted area the object is located.

[0004] Therefore, for example, Patent Document 1 describes a monitoring device with a position detection unit that includes multiple pairs of transmitters and receivers arranged to face each other in a substantially horizontal direction, and a single transmitter and multiple receivers arranged to face each other in a diagonal direction with respect to the horizontal direction. In Patent Document 1, the position of an intruder in a security area is detected using light emitted horizontally and light emitted diagonally.

[0005] Furthermore, Patent Document 2 describes a monitoring device with a position detection unit in which a transmitter and a receiver are arranged facing each other so that their transmission paths are substantially horizontal in a side view and oblique to each other in a plan view. In Patent Document 2, the passing position of an intruder is detected based on the interruption of the oblique transmission path.

[0006] Japanese Patent Application Publication No. 2016-53872 Japanese Patent Application Publication No. 2012-58880

[0007] However, in the first place, conventional intrusion detection devices using beam switches cannot determine the position of a detected object. Furthermore, the monitoring devices described in Patent Documents 1 and 2 require accurate alignment of the optical axes of multiple light projectors (transmitters in Patent Document 1 and transmitters in Patent Document 2) with different light projection directions and the corresponding light receivers (receivers in Patent Document 1 and receivers in Patent Document 2). The task of aligning the optical axes of multiple light projectors and corresponding light receivers is quite time-consuming and not easy to install.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to realize a position detection device that is easy to install.

[0009] In order to solve the above-mentioned problems, a position detection device according to one aspect of the present invention is a position detection device that detects the position of an object in an area, and includes: a first light emitter including a plurality of light-emitting elements arranged in a line that emits an identifiable first specified light into the area; a second light emitter including a plurality of light-emitting elements arranged in a line that emits an identifiable second specified light into the area; a first light receiver that receives the first specified light emitted by the first light emitter; and a second light receiver that receives the second specified light emitted by the second light emitter, The first and second light receivers are arranged at both ends of a straight line, and the second light receivers are arranged at both ends of the straight line of the plurality of light-emitting elements included in the first light emitter, the first light receiver and the second light receiver include an event-based sensor, and the event-based sensor outputs an event signal for each pixel, the event signal including the detection time at which a luminance change is detected and the pixel position at which the luminance change is detected, each time the luminance change is detected, and further includes a position detection unit that detects the position of an object in the area using the pixel position at which the luminance change is detected in the first light receiver and the pixel position at which the luminance change is detected in the second light receiver.

[0010] According to one aspect of the present invention, a position detection device can be realized that can detect the position of an object in an area without the need to align the optical axes of the first light emitter and the first light receiver, and the second light emitter and the second light receiver.

[0011] Fig. 1 is a functional block diagram showing the configuration of a main part of a position detection device according to an embodiment of the present invention. Fig. 2 is a diagram for explaining an example of position detection by the position detection device. Fig. 3 is a diagram showing the principle of position detection by the position detection device. Fig. 4 is a diagram showing the principle of position detection by the position detection device. Fig. 5 is a diagram showing the principle of position detection by the position detection device. Fig. 6 is a diagram for explaining an example of a modulation pattern of a light-emitting element.

[0012] [Outline of Detection Device] An embodiment of the present invention will be described in detail below. The position detection device 1 according to this embodiment detects the position of an object in a detection area 100. The object in the detection area 100 includes an object that has entered the detection area 100, an object that moves within the detection area 100, etc.

[0013] The position detection device 1 is a position detection device that uses a so-called beam switch. The position 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 makes it possible to realize a position detection device that is easy to install.

[0014] 1 is a functional block diagram showing the main configuration of the position detection device 1. As shown in Fig. 1, the position detection device 1 includes a control unit 10, a first light emitter 110, a second light emitter 120, a first light receiver 210, and a second light receiver 220. The control unit 10 includes a position detection unit 11 and a light-emitting element setting unit 12.

[0015] The position detection unit 11 detects the position of an object in the detection area 100. The position detection method by the position detection unit 11 will be described in detail later.

[0016] The light-emitting element setting unit 12 sets a modulation pattern for the light emitted from the light-emitting element 111 of the first light-emitting device 110 and the light-emitting element 121 of the second light-emitting device 120. The modulation pattern includes changes in amplitude (intensity), wavelength, phase, and emission pattern (on and off timing).

[0017] The light-emitting element setting unit 12 sets the modulation pattern of the light emitted from the light-emitting element 111 and the light-emitting element 121, so that the position detection unit 11 can recognize whether the light received by the first light receiver 210 and the second light receiver 220 is emitted from the first light emitter 110 and the second light emitter 120.

[0018] The light-emitting element setting unit 12 may be included in the first light receiver 210 or the second light receiver 220. When the first light receiver 210 or the second light receiver 220 includes the light-emitting element setting unit 12, the first light receiver 210 or the second light receiver 220 may directly transmit the modulation pattern set by the light-emitting element setting unit 12 to the first light emitter 110 or the second light emitter 120. This transmission may be wireless or wired.

[0019] Furthermore, the light-emitting element setting unit 12 may change the preset modulation pattern. This change may be performed when light having a modulation pattern identical to or similar to the preset modulation pattern is received from a source other than the first light-emitting device 110 or the second light-emitting device 120. This makes it possible to prevent light from being mistakenly determined to be emitted from the first light-emitting device 110 or the second light-emitting device 120 even though it is not emitted from the first light-emitting device 110 or the second light-emitting device 120. This improves the reliability of position detection by the position detection device 1.

[0020] The first light emitter 110 includes a plurality of light emitting elements 111. The second light emitter 120 includes a plurality of light emitting elements 121. The light emitting elements 111 and 121 emit modulated light, which is light modulated according to a modulation pattern set by the light emitting element setting unit 12. The modulated light is light emitted from the light emitting element 111 or the light emitting element 121, and can therefore be referred to as identifiable specific light. The light emitted from the light emitting element 111 can be referred to as first specific light, and the light emitted from the light emitting element 121 can be referred to as second specific light.

[0021] The first light receiver 210 is an imaging device that captures an image of an area including the first light emitter 110 and the detection area 100 (see FIG. 2 ), and includes a light receiving sensor 211. The second light receiver 220 is a device that captures an image of an area including the first light receiver 210 and the detection area 100, and includes a light receiving sensor 221. The light receiving sensor 211 and the light receiving sensor 221 are event-based sensors. An event-based sensor 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 a change in pixel value each time the event is detected.

[0022] Therefore, it can be said that the light receiving sensors 211 and 221 output an event signal including the detection time at which a luminance change was detected for each pixel and the pixel position at which the luminance change was detected each time a luminance change is detected.

[0023] By using event-based sensors as light-receiving sensors 211 and 221, the light emitted from first light emitter 110 can be received by first light receiver 210 even if the optical axes of first light emitter 110 and first light receiver 210 are not aligned, as long as first light emitter 110 is included in the imaging range of first light receiver 210. If first light receiver 210 can receive light, it becomes possible for first light receiver 210 to detect changes in the luminance of the light emitted from first light emitter 110. Therefore, there is no need to align the optical axes of first light emitter 110 and first light receiver 210.

[0024] Similarly, even if the optical axes of the second light emitter 120 and the second light receiver 220 are not aligned, as long as the second light emitter 120 is included in the imaging range of the second light receiver 220, the light emitted from the second light emitter 120 can be received by the second light receiver 220. If the second light receiver 220 can receive the light, it becomes possible for the second light receiver 220 to detect a change in the luminance of the light emitted from the second light emitter 120. Therefore, there is no need to align the optical axes of the second light emitter 120 and the second light receiver 220.

[0025] 2 to 6, an example of detecting the position of an object in the detection area 100 using the position detection device 1 will be described. Fig. 2 is a diagram for explaining an example of detection by the position detection device 1.

[0026] 2, the first light emitter 110 and the first light receiver 210 are arranged facing each other. Also, the second light emitter 120 and the second light receiver 220 are arranged facing each other. Here, facing each other means that the first light receiver 210 is arranged in the direction in which light from the first light emitter 110 is emitted, and the second light receiver 220 is arranged in the direction in which light from the second light emitter 120 is emitted.

[0027] The first light emitter 110 includes five light emitting elements 111, namely, light emitting element 111A to light emitting element 111E. The light emitting elements 111A to 111E are arranged in a straight line, and all emit light in the same direction.

[0028] The second light emitter 120 includes five light emitting elements 121, namely, light emitting element 121A to light emitting element 121E. The light emitting elements 121A to 121E are arranged in a straight line, and all emit light in the same direction.

[0029] The first light receivers 210 are arranged at both ends of a straight line of the plurality of light emitting elements 121 included in the second light emitter 120. Here, the first light receiver 210 arranged at one end of the straight line in which the light emitting elements 121 are arranged is referred to as first light receiver 210A, and the first light receiver 210 arranged at the other end is referred to as first light receiver 210B.

[0030] The second light receivers 220 are arranged at both ends of a straight line of the plurality of light emitting elements 111 included in the first light emitter 110. Here, the second light receiver 220 arranged at one end of the straight line in which the light emitting elements 111 are arranged is referred to as second light receiver 220A, and the second light receiver 220 arranged at the other end is referred to as second light receiver 220B.

[0031] The first light receiver 210A is disposed at a position diagonally intersecting with the second light receiver 220B, and the first light receiver 210B is disposed at a position diagonally intersecting with the second light receiver 220A.

[0032] The plurality of light-emitting elements 111 included in the first light-emitting device 110 may be arranged in a vertical line. The plurality of light-emitting elements 121 included in the second light-emitting device 120 may also be arranged in a vertical line. The first light-emitting device 110 and the second light-emitting device 120 may be arranged at the same height. As a result, the pixel position at which a luminance change is detected indicates the height in the detection area 100, making it possible to detect the height of an object in the detection area 100. It is also possible to recognize whether the object whose position has been detected is floating in the air.

[0033] Furthermore, the height including the first light emitter 110 and the second light receivers 220 arranged at both ends of the first light emitter 110 may be the same as the height including the second light emitter 120 and the first light receivers 210 arranged at both ends of the second light emitter 120.

[0034] The range through which light emitted from each of the five light-emitting elements 121 received by the first light receiver 210A passes becomes the detection area 100A. The range through which light emitted from each of the five light-emitting elements 121 received by the first light receiver 210B passes becomes the detection area 100B. The range through which light emitted from each of the five light-emitting elements 111 received by the second light receiver 220A passes becomes the detection area 100C. The range through which light emitted from each of the five light-emitting elements 111 received by the second light receiver 220B passes becomes the detection area 100D.

[0035] The combined area of ​​the detection area 100A, the detection area 100B, the detection area 100C, and the detection area 100D becomes the detection area 100 in which the position detection device 1 can detect the position of an object.

[0036] When an object is present in the detection area 100, the object blocks the light emitted from the light-emitting element 111 and the light-emitting element 121. As a result, the light-receiving sensor 211 of the first light-receiver 210 and the light-receiving sensor 221 of the second light-receiver 220 detect a change in brightness at the pixel corresponding to the position of the object. An event signal is then output.

[0037] When the position detection unit 11 receives an event signal from the light receiving sensor 211 and the light receiving sensor 221, it detects the position of 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.

[0038] More specifically, the position detection unit 11 recognizes, from the light modulation pattern and pixel positions, that the received light is emitted from a specific light-emitting element 111 of the first light-emitting device 110 and a specific light-emitting element 121 of the second light-emitting device 120. When the light emitted from the light-emitting element 111 or the light-emitting element 121 is blocked by an object or the like and the luminance changes, the position detection unit 11 detects the position of the object in the detection area 100 using the light-emitting element 111 or the light-emitting element 121 that has undergone the luminance change and the light-emitting element 111 or the light-emitting element 121 that has not undergone the luminance change.

[0039] The change in brightness that occurs in the light receiving sensors 211 and 221 used by the position detection unit 11 to detect the position of 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 sensors 211 and 221, the position detection unit 11 will not detect the position of an object in the detection area 100.

[0040] The principle by which the position detection unit 11 can detect the position of an object in the detection area 100 is as follows.

[0041] (Detection Example 1) For example, if an intruder X1 is present at a position as shown in Figure 3, of the light emitted from the light-emitting element 111 and received by the first light receiver 210A, the light emitted from the light-emitting element 111A, the light-emitting element 111B, the light-emitting element 111C, and the light-emitting element 111D are received by the first light receiver 210A, but the light emitted from the light-emitting element 111E is blocked by the intruder X1 and is not received by the first light receiver 210A.

[0042] Furthermore, of the light emitted from light-emitting element 111 and received by first light receiver 210B, the light emitted from light-emitting element 111A and light-emitting element 111B is received by first light receiver 210A, but the light emitted from light-emitting element 111C, light-emitting element 111D, and light-emitting element 111E is blocked by intruder X1 and is not received by first light receiver 210B.

[0043] If the boundary between the light received by the first light receiver 210A and the light that could not be received is defined as boundary line 301A, and the boundary between the light received by the first light receiver 210B and the light that could not be received is defined as boundary line 301B, the point where boundary line 301A and boundary line 301B intersect indicates the position of intruder X1.

[0044] If the positional relationship between the first light emitter 110 and the first light receiver 210 can be recognized in advance, it is possible to derive the position of the intersection between the boundary line 301A and the boundary line 301B in the detection area 100. Therefore, the position detection unit 11 detects the position of the intruder X1 in the detection area 100 from the intersection between the boundary line 301A and the boundary line 301B.

[0045] (Detection example 2) When an intruder X2 is present at a position as shown in Figure 4, of the light emitted from the light-emitting element 121 and received by the second light receiver 220A, the light emitted from the light-emitting element 1211A, the light-emitting element 121B, the light-emitting element 121C, and the light-emitting element 121D are received by the first light receiver 210A, but the light emitted from the light-emitting element 121E is blocked by the intruder X2 and is not received by the second light receiver 220A.

[0046] Furthermore, of the light emitted from light-emitting element 121 and received by second light receiver 220B, the light emitted from light-emitting element 121A and light-emitting element 121B is received by second light receiver 220A, but the light emitted from light-emitting element 121C, light-emitting element 121D, and light-emitting element 121E is blocked by intruder X2 and is not received by second light receiver 220B.

[0047] If the boundary between the light received by the second light receiver 220A and the light that cannot be received is defined as boundary line 302A, and the boundary between the light received by the second light receiver 220B and the light that cannot be received is defined as boundary line 302B, the point where boundary line 302A and boundary line 302B intersect indicates the position of intruder X2.

[0048] If the positional relationship between the second light emitter 120 and the second light receiver 220 can be recognized in advance, it is possible to derive the position of the intersection between the boundary line 302A and the boundary line 302B in the detection area 100. Therefore, the position detection unit 11 detects the position of the intruder X2 in the detection area 100 from the intersection between the boundary line 302A and the boundary line 302B.

[0049] (Detection Example 3) When an intruder X3 is present at a position as shown in Figure 5, of the light emitted from the light-emitting element 111 and received by the first light receiver 210A, the light emitted from the light-emitting element 1111A and the light-emitting element 111B is received by the first light receiver 210A, but the light emitted from the light-emitting element 111C, the light-emitting element 111D, and the light-emitting element 111E is blocked by the intruder X3 and is not received by the first light receiver 210A.

[0050] Furthermore, of the light emitted from light-emitting element 121 and received by second light receiver 220A, light emitted from light-emitting element 121A and light-emitting element 121B is received by second light receiver 220A, but light emitted from light-emitting element 121C, light-emitting element 121D, and light-emitting element 121E is blocked by intruder X3 and is not received by second light receiver 220A.

[0051] If the boundary between the light received by the first light receiver 210A and the light that could not be received is defined as boundary line 303A, and the boundary between the light received by the second light receiver 220A and the light that could not be received is defined as boundary line 303B, the point where boundary line 303A and boundary line 303B intersect indicates the position of intruder X3.

[0052] Then, if the positional relationship between the first light emitter 110 and the first light receiver 210, and the positional relationship between the second light emitter 120 and the second light receiver 220 can be recognized in advance, it is possible to derive the position of the intersection between the boundary line 303A and the boundary line 303B in the detection area 100. Therefore, the position detection unit 11 detects the position of the intruder X3 in the detection area 100 from the intersection between the boundary line 303A and the boundary line 303B.

[0053] (Detection Example 4) When an intruder X4 is present at a position as shown in Figure 6, of the light emitted from the light-emitting element 111 and received by the first light receiver 210B, the light emitted from the light-emitting element 1111C, the light-emitting element 111D, and the light-emitting element 111E is received by the first light receiver 210A, but the light emitted from the light-emitting element 111A and the light-emitting element 111B is blocked by the intruder X4 and is not received by the first light receiver 210B.

[0054] Furthermore, of the light emitted from light-emitting element 121 and received by second light receiver 220B, light emitted from light-emitting element 121C, light-emitting element 121D, and light-emitting element 121E is received by second light receiver 220B, but light emitted from light-emitting element 121A and light-emitting element 121B is blocked by intruder X4 and is not received by second light receiver 220B.

[0055] If the boundary between the light received by the first light receiver 210B and the light that cannot be received is defined as boundary line 304A, and the boundary between the light received by the second light receiver 220B and the light that cannot be received is defined as boundary line 304B, the point where boundary line 304A and boundary line 304B intersect indicates the position of intruder X4.

[0056] If the positional relationship between the first light emitter 110 and the first light receiver 210, and the positional relationship between the second light emitter 120 and the second light receiver 220 can be recognized in advance, it is possible to derive the position of the intersection between the boundary line 304A and the boundary line 304B in the detection area 100. Therefore, the position detection unit 11 detects the position of the intruder X4 in the detection area 100 from the intersection between the boundary line 304A and the boundary line 304B.

[0057] As described above, by using the first light receiver 210A, the first light receiver 210B, the second light receiver 220A, and the second light receiver 220B, the position of the intruder X in the detection area 100 can be detected regardless of where the intruder X is located in the detection area 100.

[0058] In the above detection examples 1 to 4, examples have been described in which the position is detected using two of the four light receivers (first light receiver 210A, first light receiver 210B, second light receiver 220A, second light receiver 220B), but this is not limited to this, and the position of an object may be detected using all four light receivers. Even when four light receivers are used, the position of the intruder X in the detection area 100 can be detected by deriving the position of the intersection of the boundary lines between light that is emitted from the light-emitting element 111 or the light-emitting element 121 and that is received by the first light receiver 210 or the second light receiver 220 and light that is not received.

[0059] Regarding a change in luminance, the position detection unit 11 may determine that the light of the light-emitting element 111 or the light-emitting element 121 corresponding to the pixel has been blocked when there is a change in luminance, or may compare the amount of change in luminance with a threshold and determine that the light of the light-emitting element 111 or the light-emitting element 121 corresponding to the pixel has been blocked when the amount of change in luminance is equal to or greater than the threshold.Furthermore, only when the luminance decreases, i.e., when it becomes darker, the position detection unit 11 may determine that the light of the light-emitting element 111 or the light-emitting element 121 corresponding to the pixel has been blocked.

[0060] Furthermore, even if natural light different from the light emitted from the first light emitter 110 or the second light emitter 120 is blocked by trees or the like and a change in brightness is detected by the first light receiver 210 or the second light receiver 220, the position detection device 1 does not perform position detection processing in the detection area 100.

[0061] As described above, the position detection device 1 according to this embodiment detects the position of an object in the detection area 100. The position detection device 1 includes, in the detection area 100, a first light emitter 110, a second light emitter 120, a first light receiver 210, a second light receiver 220, and a position detection unit 11.

[0062] The first light emitter 110 includes a plurality of light emitting elements 111 arranged in a line and emitting a first identifiable specific light. The second light emitter 120 includes a plurality of light emitting elements 121 arranged in a line and emitting a second identifiable specific light in the detection area 100.

[0063] The first light receivers 210 are arranged at both ends of the straight line of the plurality of light-emitting elements 121 included in the second light emitter 120, and receive the first specific light emitted by the first light emitter 110. The second light receivers 220 are arranged at both ends of the straight line of the plurality of light-emitting elements 111 included in the first light emitter 110, and receive the second specific light emitted by the second light emitter 120.

[0064] The first light receiver 210 includes a light receiving sensor 211, which is an event-based sensor. The second light receiver 220 includes a light receiving sensor 221, which is also an event-based sensor. The light receiving sensors 211 and 221 output an event signal, which includes the detection time when a luminance change is detected and the pixel position where the luminance change is detected, for each pixel, every time a luminance change is detected.

[0065] The position detection unit 11 detects the position of an object in the detection area 100 using the pixel position where a change in brightness is detected in the first light receiver 210 and the pixel position where a change in brightness is detected in the second light receiver 220.

[0066] When an object enters the detection area 100, a portion of the light emitted from the first light emitter 110 and the second light emitter 120 is blocked. As a result, a change in luminance is detected in the pixel corresponding to the position of the blocked light in each of the first light receiver 210 and the second light receiver 220. Then, from the pixel position where the change in luminance is detected, it is possible to recognize which light-emitting element has blocked the light emitted from.

[0067] The boundary where light is blocked by an object can be recognized from the pixel positions where a change in brightness is detected by the first light receiver 210 and the pixel positions where no change in brightness is detected. If the line indicating the boundary of light emitted from the first light emitter 110 and received by the first light receiver 210 is defined as a first line, and the line indicating the boundary of light emitted from the second light emitter 120 and received by the second light receiver 220 is defined as a second line, the intersection of the first line and the second line indicates the position of the object in the detection area 100. Therefore, the position of the object in the detection area 100 can be detected from the position of the intersection of the first line and the second line.

[0068] The first light receiver 210 and the second light receiver 220 simply receive the light emitted from the first light emitter 110 and the second light emitter 120, and therefore no work such as aligning the optical axes is required. Therefore, it is possible to realize the position detection device 1 that detects the position of an object in the detection area 100 without the need for the time-consuming work of aligning the optical axes.

[0069] Furthermore, the first light emitter 110 and the first light receiver 210, and the second light emitter 120 and the second light receiver 220 may be spaced apart by a predetermined distance or more, for example, 500 m or more. In a conventional configuration, it is necessary to align the optical axes of the light emitter and the light receiver, so it is difficult to arrange them apart by a long distance, for example, 500 m or more.

[0070] As described above, the position detection device 1 does not require the task of aligning the optical axes of the first light emitter 110 and the first light receiver 210, and the second light emitter 120 and the second light receiver 220. As long as the light emitted from the first light emitter 110 or the second light emitter 120 can be received by the first light receiver 210 or the second light receiver 220, the position of an object within the detection area 100 can be accurately detected even when the first light emitter 110 and the first light receiver 210, and the second light emitter 120 and the second light receiver 220 are separated by 500 m or more.

[0071] [Example of modulation pattern of light-emitting element] Next, an example of the modulation pattern of the light-emitting element 111 will be described with reference to Fig. 7. Note that the modulation pattern of the light-emitting element 111 can be similarly applied to the light-emitting element 121. Fig. 7 is a diagram for explaining an example of the modulation pattern of the light-emitting element 111. Fig. 7 shows an example in which the first light emitter 110 includes 15 light-emitting elements 111. Here, these elements are designated as light-emitting elements 111X1 to 111X5, light-emitting elements 111Y1 to 111Y5, and light-emitting elements 111Z1 to 111Z5, respectively.

[0072] One example is to divide the light-emitting elements 111 into a plurality of groups, and emit light with a different modulation pattern for each group. For example, 15 light-emitting elements 111 are divided into three groups, light-emitting elements 111X, light-emitting elements 111Y, and light-emitting elements 111Z, and light-emitting elements 11X, light-emitting elements 111Y, and light-emitting elements 111Z emit light with different modulation patterns. Note that light-emitting elements 111X include light-emitting elements 111X1 to light-emitting element 111X5. Light-emitting element 111Y includes light-emitting elements 111Y1 to light-emitting element 111Y5. Light-emitting element 111Z includes light-emitting elements 111Z1 to light-emitting element 111Z5.

[0073] If light emitting element 111X emits light of modulation pattern A, light emitting element 111Y emits light of modulation pattern B, and light emitting element 111Z emits light of modulation pattern C, then when first light receiver 210 receives light of modulation pattern A, it can recognize that the light is emitted from light emitting element 111X. Furthermore, when first light receiver 210 receives light of modulation pattern B, it can recognize that the light is emitted from light emitting element 111Y. Furthermore, when first light receiver 210 receives light of modulation pattern C, it can recognize that the light is emitted from light emitting element 111Z.

[0074] As another example, light-emitting elements 111X1, 111Y1, and 111Z1 may be grouped together, light-emitting elements 111X2, 111Y2, and 111Z2 may be grouped together, light-emitting elements 111X3, 111Y3, and 111Z3 may be grouped together, light-emitting elements 111X4, 111Y4, and 111Z4 may be grouped together, and light-emitting elements 111X5, 111Y5, and 111Z5 may be grouped together, and each group may emit light using a different modulation pattern.

[0075] If the resolution of the light receiving sensor 211 of the first light receiver 210 is not sufficient to distinguish all of the light emitting elements 111 of the first light emitter 110, for example because the distance between the first light emitter 110 and the first light receiver 210 is large, the first light receiver 210 will not be able to grasp the exact position of each light emitting element 111.

[0076] 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 111. Therefore, even if the resolution of the light-receiving sensor 211 is not sufficient to distinguish between all of the light-emitting elements 111, it is possible for the first light-receiver 210 to distinguish between the light-emitting elements 111.

[0077] Furthermore, the light emitting elements 111 may be emitted at different timings for each group. In the case where the light emitting timings are different for each group, as in the case where the modulation patterns are different, even if the resolution of the light receiving sensor 211 is not sufficient to distinguish all of the light emitting elements 111, the first light receiver 210 can still distinguish the light emitting elements 111.

[0078] [Example of implementation using software] The functions of the position 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).

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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).

[0083] 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.

[0084] [Summary] A position detection device according to a first aspect of the present invention is a position detection device that detects the position of an object in an area, and includes: a first light emitter including a plurality of light-emitting elements arranged in a line that emits an identifiable first specified light into the area; a second light emitter including a plurality of light-emitting elements arranged in a line that emits an identifiable second specified light into the area; a first light receiver that receives the first specified light emitted by the first light emitter; and a second light receiver that receives the second specified light emitted by the second light emitter, wherein the first light receivers are arranged at both ends of the line of the plurality of light-emitting elements included in the second light emitter. the second light receivers are arranged at both ends of the straight line of the plurality of light-emitting elements included in the first light emitter, the first light receiver and the second light receiver include event-based sensors, the event-based sensors outputting, for each pixel, an event signal including a detection time at which a luminance change is detected and a pixel position at which the luminance change is detected, each time the luminance change is detected, and the position detection unit is further provided with a position detection device that detects a position in the area of ​​an object in the area using the pixel position at which the luminance change is detected in the first light receiver and the pixel position at which the luminance change is detected in the second light receiver.

[0085] Light emitted from the first light emitter is received by the first light receiver. Light emitted from the second light emitter is received by the second light receiver. The first light receivers are disposed on both ends of the linear array of light-emitting elements of the second light emitter, and the second light receivers are disposed on both ends of the linear array of light-emitting elements of the first light emitter. Thus, the first light emitter and the second light emitter are disposed opposite each other.

[0086] When an object enters the area and blocks the light emitted from the first light emitter and the second light emitter, it is possible to determine which light-emitting element has blocked the light from the pixel position where the brightness change is detected in each of the first light receiver and the second light receiver.

[0087] Here, the boundary where light is blocked by an object can be recognized from the pixel positions where a change in luminance is detected in the first light receiver and the pixel positions where no change in luminance is detected.

[0088] If the line indicating the boundary of the light emitted from the first light emitter and received by the first light receiver is called the first line, and the line indicating the boundary of the light emitted from the second light emitter and received by the second light receiver is called the second line, the intersection of the first line and the second line indicates the position of the object in the area. Therefore, the position of the object in the area can be detected from the position of the intersection of the first line and the second line.

[0089] Therefore, with the above configuration, it is possible to realize a position detection device that can detect the position of an object in an area without the need to align the optical axes of the first light emitter and the first light receiver, and the optical axes of the second light emitter and the second light receiver.

[0090] In a position detection device according to a second aspect of the present invention, in the first aspect, the first specified light and the second specified light are modulated light. With this configuration, it is possible to easily identify whether the light is emitted from a light-emitting element.

[0091] A position detection device according to aspect 3 of the present invention is such that, in aspect 1 or 2, the plurality of light-emitting elements included in the first light-emitting device are arranged in a vertical line, the plurality of light-emitting elements included in the second light-emitting device are arranged in a vertical line, and the first light-emitting device and the second light-emitting device are arranged at the same height.

[0092] According to the above configuration, the pixel position where the brightness change is detected indicates the height in the area. Therefore, the height of the object in the area can be detected. It can also be recognized whether the object is floating in the air.

[0093] A position detection device according to aspect 4 of the present invention is any one of aspects 1 to 3, wherein the first light emitter and the first light receiver, and the second light emitter and the second light receiver are separated by 500 m or more.

[0094] In conventional configurations, the optical axes of the light emitter and the light receiver must be aligned, making it difficult to place them over long distances, for example, 500 m or more. According to the above configuration, the light emitted from the first light emitter and the second light receiver is received by the event-based sensors included in the first light receiver and the second light receiver, respectively. Therefore, alignment of the optical axes is no longer necessary, and the position of an object within the area can be accurately detected even when the first light emitter and the first light receiver, and the second light emitter and the second light receiver, are separated by 500 m or more.

[0095] A position detection device according to aspect 5 of the present invention is any of aspects 1 to 4, in which the plurality of light-emitting elements included in the first light-emitting device are divided into a plurality of groups, and the first light-emitting device emits light with a modulation pattern of the light-emitting elements that differs for each group, and the plurality of light-emitting elements included in the second light-emitting device are divided into a plurality of groups, and the second light-emitting device emits light with a modulation pattern of the light-emitting elements that differs for each group.

[0096] According to the above configuration, the modulation pattern of the light-emitting elements differs 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.

[0097] A position detection device according to a sixth aspect of the present invention is based on the fifth aspect, and wherein the first light emitter and the second light emitter emit light with the light emitting elements of the light emitting elements emitting light at different light emission timings for each of the groups.

[0098] 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.

[0099] 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.

[0100] REFERENCE SIGNS LIST 1 Position detection device 10 Control unit 11 Position detection unit 12 Light-emitting element setting unit 100 Detection area 110 First light emitter 111, 111A to 111E Light-emitting element 120 Second light emitter 121, 121A to 121E Light-emitting element 210, 210A, 210B First light receiver 211 Light-receiving sensor 220, 220A, 220B Second light receiver 221 Light-receiving sensor

Claims

1. A position detection device for detecting the position of an object within an area, comprising: a first light emitter including a plurality of linearly arranged light-emitting elements that emit a first identifiable specific light into the area; a second light emitter including a plurality of linearly arranged light-emitting elements that emit a second identifiable specific light into the area; a first light receiver that receives the first specific light emitted by the first light emitter; and a second light receiver that receives the second specific light emitted by the second light emitter, wherein the first light receiver is disposed at both ends of the straight line of the plurality of light-emitting elements included in the second light emitter, the second light receiver is disposed at both ends of the straight line of the plurality of light-emitting elements included in the first light emitter, the first light receiver and the second light receiver include event-based sensors, and the event-based sensors output an event signal including a detection time at which a luminance change is detected and a pixel position at which the luminance change is detected for each pixel every time the luminance change is detected, and further comprising a position detection unit that detects the position of the object within the area using the pixel position at which the luminance change is detected in the first light receiver and the pixel position at which the luminance change is detected in the second light receiver.

2. The position detection device according to claim 1, wherein the first specific light and the second specific light are modulated light.

3. The position detection device according to claim 1, wherein the plurality of light-emitting elements included in the first light emitter are linearly arranged vertically, the plurality of light-emitting elements included in the second light emitter are linearly arranged vertically, and the first light emitter and the second light emitter are disposed at the same height.

4. The position detection device according to claim 1, wherein the first light emitter and the first light receiver, and the second light emitter and the second light receiver are separated by 500 m or more.

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

6. The position detection device according to claim 5, wherein the first light emitter and the second light emitter emit light with different emission timings of the light emitting elements for each of the groups.

Images