Source direction estimation device, source direction estimation system, infrared emitter, robot, source direction estimation method and program, object presence direction estimation system

Abstract

Accurately estimate the direction of transmission. [Solution] The source direction estimation device (20) comprises a plurality of infrared light receiving elements (21a) to (21d) with different light receiving directions, and a direction estimation unit (22) that estimates the direction of the infrared light source based on the amount of light received by each of the infrared light receiving elements (21a) to (21d) within a predetermined time.

Description

Technical Field

[0001] The present invention relates to a transmission source direction estimation device that estimates the direction of an infrared transmission source.

Background Art

[0002] Conventionally, a transmission source direction estimation device that estimates the direction of a certain direction of an infrared light emitting device by using the directivity of infrared rays has been known. Patent Document 1 discloses an invention in which a device for estimating the direction of a transmission source is applied to robot navigation. In the invention according to Patent Document 1, a signal transmission device that transmits a predetermined signal to a destination is installed, and the signal transmitted from the signal transmission device is received by a robot carried by a user, and the robot is guided to the destination by its operation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An apparatus for estimating the direction of an infrared transmission source includes a plurality of infrared light receiving units having different light receiving directions, and estimates the light receiving direction based on which infrared light receiving unit receives infrared light. However, since the plurality of infrared light receiving units are arranged so as to face different light receiving directions at a certain angular interval, when the transmission source is in a direction intermediate between the light receiving directions of adjacent infrared light receiving units, the following situation may occur.

[0005] Here, we assume two infrared receivers, A and B. If the infrared source is closer to the receiving direction of infrared receiver A, ideally infrared receiver A would receive the infrared light. However, infrared receiver B may also receive infrared light, and infrared receiver A may or may not receive infrared light. In such cases, the reception result (received / not received) by infrared receiver A may fluctuate, and the estimated direction may also fluctuate.

[0006] In view of the above background, the present invention aims to provide a source direction estimation device, etc., that can stably estimate the direction of the source. [Means for solving the problem]

[0007] The present invention provides a transmission direction estimation device comprising a plurality of infrared light receiving units with different light receiving directions, and a direction estimation unit that estimates the direction of the infrared light source based on the amount of light received by each of the infrared light receiving units within a predetermined time. [Effects of the Invention]

[0008] According to the present invention, the direction of the source can be reliably estimated. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows the configuration of the source direction estimation system according to the first embodiment. [Figure 2A] Figure 2A shows the light emission timing of an infrared light-emitting element. [Figure 2B] Figure 2B shows the light emission timing of multiple infrared light-emitting elements. [Figure 3] Figure 3 shows the principle of source direction estimation using the source direction estimation device of the first embodiment. [Figure 4] Figure 4 shows the principle of source direction estimation using the source direction estimation device of the second embodiment. [Figure 5A]Figure 5A shows the principle of source direction estimation using the source direction estimation device of the second embodiment. [Figure 5B] Figure 5B shows the principle of source direction estimation using the source direction estimation device of the second embodiment. [Figure 6] Figure 6 is a flowchart showing the operation of the source direction estimation device according to the second embodiment. [Figure 7] Figure 7 shows the change in the intensity of infrared radiation output from the light-emitting device in the third embodiment. [Figure 8] Figure 8 shows the configuration of the source direction estimation device according to the third embodiment. [Figure 9] Figure 9 is a flowchart showing the operation of the source direction estimation device according to the third embodiment. [Figure 10A] Figure 10A is a schematic diagram showing a robot equipped with a source direction estimation system according to the fourth embodiment. [Figure 10B] Figure 10B is a cross-sectional view of BB in Figure 10A. [Figure 11] Figure 11 shows the configuration of the robot according to the fourth embodiment. [Figure 12] Figure 12 shows the configuration of a direction estimation device used in a robot. [Figure 13] Figure 13 shows the configuration of a robot orientation estimation system mounted on a robot. [Figure 14] Figure 14 is a flowchart showing the third method of integrating estimation results by the estimation result integration unit. [Figure 15] Figure 15 is a flowchart showing the fourth method of integrating estimation results by the estimation result integration unit. [Modes for carrying out the invention]

[0010] The transmission source direction estimation device according to the embodiment includes a plurality of infrared light receiving units with different light receiving directions, and a direction estimation unit that estimates the direction of the infrared transmission source based on the light reception amounts of each of the infrared light receiving units within a predetermined time. By estimating the direction of the transmission source based on the light reception amounts received by each infrared light receiving unit within a predetermined time, it is possible to reduce the inconvenience that the direction estimated as the transmission source easily changes due to a slight change in the environment or the like.

[0011] In the transmission source direction estimation device according to the embodiment, the infrared light receiving unit restores the received infrared light into packets according to a predetermined communication protocol, and the direction estimation unit estimates the direction of the infrared transmission source based on the number of packets received by each of the infrared light receiving units within the predetermined time. With this configuration, as the light reception amount, the number of restored packets is counted, and based on the number of packets, the transmission source direction can be accurately estimated.

[0012] In the transmission source direction estimation device according to the embodiment, the direction estimation unit may estimate the direction of the infrared transmission source based on, in addition to the number of packets received by each of the infrared light receiving units within the predetermined time, the number of data that did not constitute packets. By using not only the number of packets but also the number of data as the light reception amount in this way, the information used for direction estimation increases, and the accuracy can be improved.

[0013] In the transmission source direction estimation device according to the embodiment, the direction estimation unit estimates the direction of the infrared transmission source based on the number of packets and the number of data received by the infrared light receiving unit with the largest number of received packets and the number of packets and the number of data received by the infrared light receiving unit having a light receiving direction adjacent to the light receiving direction of the infrared light receiving unit. By using the infrared light receiving unit with the largest number of received packets that can be correctly received and the infrared light receiving units with adjacent light receiving directions, the transmission source can be accurately estimated.

[0014] Another embodiment of the source direction estimation device includes a plurality of infrared light receiving units with different light receiving directions, and a direction estimation unit that estimates the light receiving direction of an infrared light receiving unit as the direction of the infrared source when the amount of light received by any of the infrared light receiving units reaches a predetermined threshold, and the time until the amount reaches the predetermined threshold is within a predetermined time. With this configuration, the direction of the source is estimated when the amount of light received reaches a predetermined threshold, thus reducing the inconvenience of the direction estimated as the source easily changing due to slight environmental changes, etc. Here, the predetermined threshold may be defined, for example, by the number of packets received by the infrared light receiving unit. For example, the direction estimation unit may determine that the amount of light received by an infrared light receiving unit has reached a predetermined threshold when it has received three packets.

[0015] In another embodiment of the source direction estimation device, the direction estimation unit may estimate the direction of the infrared source based on the current estimation result and past estimation results. By using past estimation results in addition to the current estimation result in this way, a highly accurate estimation can be performed.

[0016] The source direction estimation system of this embodiment comprises a source device having an infrared light-emitting unit and the source direction estimation device described above. With this configuration, the direction of the source device can be estimated.

[0017] The source direction estimation system of the embodiment comprises a source device having a plurality of infrared light-emitting units with different emission directions and an emission control unit that controls the emission timing of each infrared light-emitting unit so that they do not overlap, and the source direction estimation device described above. In this way, the source device has a plurality of infrared light-emitting units with different emission directions and emits infrared rays over a wide area of ​​the surroundings, so that the source direction estimation device can estimate the direction of the source over a wide area.

[0018] In the source direction estimation system of the embodiment, the infrared emitter may emit infrared light at a constant period and with varying output intensity. If the infrared output is low, it is difficult to estimate the direction when the source device is far away, and if the infrared output intensity is high, there will be a lot of reflected infrared light when there are multiple source devices, making direction estimation difficult. By changing the output intensity, when the infrared emitter of the source is far away, the direction can be estimated using infrared light with high output intensity, and when the infrared emitter of the source is nearby, the direction can be appropriately estimated using infrared light with low output intensity.

[0019] In the source direction estimation system of this embodiment, the infrared emitter changes the output intensity of the infrared radiation within a predetermined output intensity range, the source direction estimation device transmits information on the received infrared radiation output intensity to the infrared emitter, and the infrared emitter may change the output intensity range based on the infrared radiation output intensity received by the source direction estimation device. The source direction estimation device does not need to know the absolute value of the infrared radiation output intensity in the infrared emitter; it only needs to know the relative output intensity among the infrared radiation transmitted by periodically changing the output intensity. By transmitting this information to the infrared emitter, the infrared emitter can know which output intensity of infrared radiation was received.

[0020] With this configuration, if the infrared output intensity received by the source direction estimation device is a relatively low output intensity within a predetermined output intensity range, it is considered that the distance between the source direction estimation device and the infrared emitter is close, so the output intensity range is shifted to the lower end. If the infrared output intensity received by the source direction estimation device is only a relatively high output intensity within a predetermined output intensity range, it is considered that the distance between the source direction estimation device and the infrared emitter is far, so the output intensity range is shifted to the higher end.

[0021] In the source direction estimation system of this embodiment, the infrared light emitter may emit infrared light with low output intensity at a higher frequency than infrared light with high output intensity. When the infrared light emitter of the source is nearby, errors may occur due to the reflection of infrared light with high output intensity, but the configuration of this embodiment can reduce the frequency of such errors.

[0022] In the source direction estimation system of this embodiment, the infrared light emitter transmits a packet containing information indicating the output intensity of the infrared radiation, and the source direction estimation device may include a distance estimation unit that estimates the distance to the source infrared light emitter based on the information indicating the output intensity contained in the packet received by the infrared light receiver. With this configuration, the approximate distance to the source can be estimated.

[0023] Another embodiment of the source direction estimation system is a source direction estimation system comprising a source device and the source direction estimation device described above, wherein the source device comprises a plurality of infrared light-emitting units with different emission directions, each of which transmits a packet containing a source identifier of the infrared light-emitting unit, and a communication unit that communicates with the source direction estimation device. The source direction estimation device may also include a communication unit that transmits the source identifier contained in the packet used to estimate the source. This allows the source device to know which of the multiple infrared emitters transmitted the packet that was received by the source direction estimation device, and thus determine the direction of the source direction estimation device from the source device's perspective.

[0024] The infrared light emitter of this embodiment is an infrared light emitter that outputs infrared light used for direction estimation, and emits infrared light that includes infrared light with low output intensity at a higher frequency than infrared light with high output intensity.

[0025] The infrared light emitter of the embodiment may include information indicating the output intensity of the infrared light in a packet composed of infrared data.

[0026] The robot of this embodiment includes an infrared emitter that emits infrared light, a plurality of infrared light receiving units with different receiving directions, and a direction estimation unit that estimates the direction of the infrared light source based on the amount of light received by each of the infrared light receiving units within a predetermined time. With this configuration, in an environment where multiple robots are present, the direction of other robots can be estimated using infrared light.

[0027] The method for estimating the direction of the source of infrared radiation according to the embodiment includes the steps of: receiving infrared radiation with a plurality of infrared light receiving units having different light receiving directions; measuring the amount of light received by each of the infrared light receiving units within a predetermined time; and estimating the direction of the source of infrared radiation based on the amount of light received by each of the infrared light receiving units.

[0028] The program of the embodiment is a program for estimating the direction of a source of infrared radiation based on infrared radiation received by a plurality of infrared light receiving units with different light receiving directions, and causes a computer connected to the infrared light receiving units to perform the following steps: receiving infrared radiation from the plurality of infrared light receiving units; measuring the amount of light received by each of the infrared light receiving units within a predetermined time; and estimating the direction of the source of the infrared radiation based on the amount of light received by each of the infrared light receiving units.

[0029] The object location direction estimation system of this embodiment is a system for estimating the direction in which an object exists, comprising a source device having an infrared light emitter and an audio output device that outputs sound, the system comprising: a source location direction estimation device that estimates the direction of the source based on infrared light transmitted from the object's source device; a DOA detection device that detects the direction of arrival of sound output from the object's audio output device; an image recognition device that recognizes the object from an image captured by a camera that photographs the surrounding area and estimates the direction in which the object exists; and an estimation result integration unit that determines the shooting direction by the camera based on the infrared source direction estimated by the source location direction estimation device and the direction of arrival of sound detected by the DOA detection device, instructs the camera to shoot in that direction, and estimates the direction estimated by the image recognition device based on the image captured in the shooting direction as the direction in which the object exists. With this configuration, the direction in which an object exists can be estimated based on the estimation results of the source location direction estimation device, the DOA detection device, and the image recognition device, respectively.

[0030] Another embodiment of the object location direction estimation system is a system for estimating the direction of an object equipped with a source device having an infrared light emitter, comprising: a source direction estimation device described above that estimates the direction of the source based on infrared light transmitted from the source device of the object; an image recognition device that recognizes the object from an image captured by a camera that photographs the surrounding area and estimates the direction in which the object exists; and if there is an overlap between the infrared source direction estimated by the source direction estimation device and the direction of the object recognized by the image recognition device, the estimation result by the image recognition device is estimated to be the direction in which the object exists, and if there is no overlap, The system includes an estimation result integration unit that determines the shooting direction of the camera based on the infrared source direction estimated by the source direction estimation device, instructs the camera to shoot in that direction, and estimates the direction in which the object exists based on the image taken in the shooting direction, which is estimated by the image recognition device. With this configuration, the direction in which the object exists can be estimated based on the estimation results from the source direction estimation device and the image recognition device, respectively.

[0031] Another embodiment of the object location direction estimation system is a system for estimating the direction of an object, comprising a source device having an infrared emitter and an audio output device that outputs sound, the system comprising: a source location direction estimation device that estimates the direction of the source based on infrared radiation transmitted from the object's source device; a DOA detection device that detects the direction of arrival of sound output from the object's audio output device; an image recognition device that recognizes the object from an image captured by a camera that photographs the surroundings and estimates the direction in which the object exists; and an estimation result integration unit that integrates the source direction of the infrared radiation estimated by the source location direction estimation device, the direction of arrival of the sound detected by the DOA detection device, and the direction of the object recognized by the image recognition device to estimate the direction in which the object exists, wherein the estimation result integration unit disables the source location direction estimation device in environments where the amount of infrared radiation is above a predetermined threshold, activates the DOA detection device in environments where ambient noise is above a predetermined threshold, and disables the image recognition device in environments where brightness is below a predetermined threshold. With this configuration, accurate estimation can be achieved by disabling estimation results that do not yield accurate results depending on the environment.

[0032] The following description of the embodiment of the source direction estimation device and the robot equipped therewith will be given with reference to the drawings. (First Embodiment) Figure 1 shows the configuration of the source direction estimation system 1 according to the first embodiment. The source direction estimation system 1 comprises a source device 10 that emits infrared light and a source direction estimation device 20 that receives the infrared light emitted from the source device 10 and estimates the direction of the source.

[0033] The source device 10 has four infrared light-emitting elements 11a to 11d with different emission directions, and an emission control unit 12 that controls the emission timing of the infrared light-emitting elements 11a to 11d. When referring to the infrared light-emitting elements 11a to 11d collectively, or when not limiting to specific infrared light-emitting elements 11a to 11d, the term "infrared light-emitting element 11" is used. In this embodiment, the source device 10 is equipped with four infrared light-emitting elements 11a to 11d in order to emit infrared light in all directions around the source device 10, but the number of infrared light-emitting elements 11 is not limited to four. For example, if it is not necessary to emit infrared light in all directions, the number of infrared light-emitting elements 11 may be reduced. Conversely, the number of infrared light-emitting elements 11 may be increased to increase the density of infrared light.

[0034] Figure 2A shows the emission timing of the infrared light-emitting element 11. The infrared light-emitting element 11 emits infrared light (IR) at a predetermined period T. The infrared light (IR) is a packet configured according to a predetermined protocol. For example, it has a configuration of 0xFA, 0x9n, 8 bytes of user data, and a checksum.

[0035] Figure 2B shows the emission timing of the four infrared light-emitting elements 11a to 11d. The emission period T of each infrared light-emitting element 11a to 11d is the same as the emission period T shown in Figure 2A, but the emission timing of the four infrared light-emitting elements 11a to 11d is staggered so that they do not overlap.

[0036] As shown in Figure 1, the source direction estimation device 20 uses four light-receiving elements 21a to 21d with different light-receiving directions and the amount of light received by each light-receiving element 21a to 21d to determine the direction of the infrared source. It has a direction estimation unit 22 that estimates the source direction. When referring to the light-receiving elements 21a to 21d collectively or when not limiting to specific light-receiving elements 21a to 21d, it is referred to as "light-receiving element 21". The four light-receiving elements 21a to 21d cover all directions around the source direction estimation device 20, so that no matter which direction the infrared radiation comes from, one of the four light-receiving elements 21a to 21d will receive the infrared radiation. Note that the number of light-receiving elements 21 is not limited to four; for example, it may be equipped with six or eight light-receiving elements 21.

[0037] The direction estimation unit 22 has the function of estimating the direction of the infrared source, that is, the direction of the source device 10, based on the light reception results from the four light receiving elements 21a to 21d.

[0038] Figure 3 shows the principle by which the direction estimation unit 22 estimates the direction of the infrared source. Figure 3 also shows the number of infrared packets received by each light receiving element 21.

[0039] The direction estimation unit 22 estimates that the direction of reception of the photodetector 21 that received the most infrared light within a predetermined time is the direction of the source. In this embodiment, the direction of reception of the photodetector that received the most packets is estimated to be the direction of the source. In the example shown in Figure 3, the number of packets received by the photodetector 21a is the maximum at "3", so the direction of reception of the photodetector 21a, which is upward on the paper, is estimated to be the direction of the source. The predetermined time depends on the emission period of the infrared light, but for example, if the emission period is 110 ms, it is preferable to set it to about 1 second.

[0040] The configuration of the source direction estimation system 1 of the first embodiment has been described above. The source direction estimation device 20 of the first embodiment is equipped with a plurality of light-receiving elements 21a to 21d with different light-receiving directions, and estimates the direction of the infrared source based on the number of infrared packets (i.e., the amount of light received) that each light-receiving element 21a to 21d receives within a predetermined time. In other words, instead of simply using the light-receiving direction of the light-receiving element 21a to 21d that received the packets, the direction with the greatest amount of light received within a predetermined time is used as the light-receiving direction, thus reducing the inconvenience of the estimated direction of the source easily changing due to slight environmental changes, etc.

[0041] (Second Embodiment) Next, the source direction estimation system of the second embodiment will be described. The basic configuration of the source device 10 used in the source direction estimation system of the second embodiment is the same as that of the first embodiment. The source direction estimation device 20 of the second embodiment differs from the source direction estimation device 20 of the first embodiment in the process of estimating the source in the direction estimation unit 22.

[0042] Figure 4 shows the principle of source direction estimation by the source direction estimation device 20 of the second embodiment. The source direction estimation device 20 of the second embodiment estimates the direction of the source based on the total number of infrared data received by each photodetector 21a to 21d. Here, "number of data" will be explained. One packet is transmitted by one infrared light as explained in Figure 2A. A packet is a unit of information configured according to a predetermined protocol, and includes a header, user data, checksum, etc. One packet is composed of multiple data (sometimes called a "frame"). Depending on the protocol followed, one packet consists of, for example, 11 data. The length of each data is 1 byte. If one packet consists of 11 data, then receiving one packet means receiving 11 data.

[0043] In the source direction estimation system of the second embodiment, the direction estimation unit 22, upon receiving infrared radiation, reconstructs the packets according to a predetermined protocol and counts the number of packets that were successfully reconstructed. In addition, the direction estimation unit 22 also considers cases other than when infrared radiation is received in the form of packets. Furthermore, the number of data points is also counted when data that does not constitute a packet is received.

[0044] Figure 4 shows an example of the number of packets and data received by each photodetector 21a to 21d. As shown in Figure 4, the direction estimation unit 22 also counts the number of noise errors. A noise error occurs when the received value does not stabilize between 0 and 1 within the time required for one bit, during which the infrared light should ideally be stable as either ON or OFF. To observe the stability of such signals and to improve resistance to noise and clock deviations, the photodetector 21 samples the signal multiple times per bit (for example, 16 times).

[0045] The source direction estimation device 20 of this embodiment uses the amount of light received, which is the total number of data (= number of packets × 11 + number of data) received by each light-receiving element 21a to 21d corrected by the number of noise errors, as the amount of light received, and estimates the direction of the infrared source based on this amount of light received. There are various ways to correct by the number of noise errors, but in this embodiment, the number of noise errors × 2 is subtracted. For example, in the example shown in Figure 4, the total number of data received by light-receiving element 21a is 4 × 11 + 10 = 54, and when corrected by the number of noise errors, it becomes 54 - 2 × 2 = 50. The total number of data received by light-receiving element 21b is 1 × 11 + 7 = 18, and when corrected by the number of noise errors, it becomes 18 - 4 × 2 = 10. The total number of data received by light-receiving element 21d is 10, and when corrected by the number of noise errors, it becomes 10 - 3 × 2 = 4. The source direction estimation device 20 of the second embodiment estimates the direction of the source based on the total number of data points of the light-receiving element 21 with the largest number of received packets and the two adjacent light-receiving elements 21. In the example shown in Figure 4, the light-receiving elements 21a and 21b, and the reception results from light-receiving element 21b are used.

[0046] Figure 5A illustrates the principle of source direction estimation by the source direction estimation device 20. The Y-axis represents the total number of data packets received in the light-receiving direction with the maximum number of packets, and the X-axis represents the number of data packets received by the adjacent light-receiving elements 21, with the X-axis representing the positive and negative numbers. The X and Y axes are set arbitrarily for the sake of explanation, but the directions -X, +Y, +X, -Y are set to coincide with the light-receiving directions of the light-receiving elements 21a to 21d shown in Figure 1. For example, if the source direction estimation device 20 has three light-receiving elements arranged at equal angles, the directions indicating the number of data packets will be represented by axes at 120-degree intervals.

[0047] Figure 5A shows the number of data points received from each light-receiving direction as a vector. That is, the direction of the vector indicates the light-receiving direction, and the length of the vector indicates the number of data points received. Although vector notation is used in the figure, this book will use regular letters.

[0048] The source direction estimation device 20 first adds up the number of data received by the two adjacent photodetectors 21. Specifically, it adds vector D2 and vector D3. Since vectors D2 and D3 have opposite directions, their magnitudes cancel each other out. Next, it adds vector D1, which represents the total number of data received by the photodetector 21 with the largest number of received packets, to vector (D2+D3), which represents the number of data received by the two adjacent photodetectors 21. As shown in Figure 5B, the resulting direction vector (D1+D2+D3) is estimated to be the direction of the infrared source. Here, an example of adding vectors D1 to D3 sequentially has been explained, but vector addition can also be performed simultaneously.

[0049] Figure 6 is a flowchart showing the operation of the source direction estimation device 20 of the second embodiment. The source direction estimation device 20 of the second embodiment receives data at each of the photodetectors 21a to 21d (S10). The source direction estimation device 20 counts the number of received packets, the number of received data, and the number of noise errors at each of the photodetectors 21a to 21d within the most recent predetermined time (S11). Subsequently, it corrects the number of noise errors and calculates the total number of received data at each of the photodetectors 21a to 21d (S12). Specifically, as described above, the total number of received data is calculated as the number of received packets × 11 + the number of data, and the number of noise errors × 2 is subtracted from the total number of received data. This allows us to determine the total number of corrected received data.

[0050] Next, the source direction estimation device 20 selects the total number of data points from the light-receiving element 21 with the largest number of received packets and the light-receiving elements 21 on either side of it (S13), and calculates the angle of the source direction from the total number of received data points (S14).

[0051] The source direction estimation device 20 of the second embodiment can increase the amount of information used for direction estimation and improve estimation accuracy by using not only the number of received packets but also the number of data that could not be received as packets. Furthermore, the source direction estimation device 20 of the second embodiment employs a configuration that uses the total number of data received by the light-receiving element 21 with the largest number of received packets and the light-receiving elements 21 on either side of it, enabling accurate estimation of the source centered on the direction with the largest number of correctly received packets.

[0052] In this embodiment, the total number of received data is corrected based on the number of noise errors. However, to simplify the process, it is possible to omit the correction based on the number of noise errors. Even without correction based on the number of noise errors, the source can be estimated with a certain level of accuracy.

[0053] (Third embodiment) Next, the source direction estimation system of the third embodiment will be described. The basic configuration of the source direction estimation system of the third embodiment is the same as that of the source direction estimation system of the second embodiment, but in the third embodiment, the source direction estimation device 20 estimates not only the direction of the source but also the distance to the source. In the third embodiment, the source device 10 periodically changes the intensity of the infrared radiation it emits.

[0054] Figure 7 shows the intensity of infrared light emitted by the source device 10. The infrared light emitted by the source device 10 has multiple different intensities, "weak," "medium," "weak," "medium," "weak," and "strong," with six infrared rays forming one set. The source device 10 also includes information indicating the output intensity of the infrared light in each packet it transmits.

[0055] Figure 8 shows the configuration of the source direction estimation device 20 of the third embodiment. The source direction estimation device 20 of the third embodiment has, in addition to the configuration of the source direction estimation device 20 of the second embodiment, a distance estimation unit 23 that estimates the distance to the source device 10.

[0056] Figure 9 is a flowchart showing the operation of the source direction estimation device 20 of the third embodiment. The operation of the source direction estimation by the source direction estimation device 20 of the third embodiment (S10 to S14) is the same as that of the source direction estimation device 20 of the second embodiment. The source direction estimation device 20 of the third embodiment estimates the distance to the source device 10 based on the direction of the source device 10 and the minimum infrared output (S15).

[0057] Specifically, the distance estimation unit 23 reads information indicating the intensity of infrared radiation from the received infrared packets. It then determines whether the minimum output of the received infrared radiation was "weak," "medium," or "strong," and estimates the distance to the source device 10. For example, if the minimum output is "strong," it means that only high-power infrared light reached the source, so it is determined that the source device 10 is far away. If the minimum output is "weak," it is determined that the source device 10 is nearby. Alternatively, the source direction estimation device 20 may store output intensity data corresponding to "weak," "medium," and "strong," and estimate the distance to the source device 10 from the degree of attenuation of the received infrared intensity. This allows for a more accurate determination of the distance.

[0058] The source direction estimation system of the third embodiment can estimate the distance to the source based on information indicating the output intensity of the received infrared radiation. In addition to the benefit of being usable for distance estimation, varying the output intensity of the line has the effect of enabling accurate direction estimation based on infrared radiation from the source device 10.

[0059] To properly receive infrared radiation when the distance to the infrared source device 10 is large, it is necessary to increase the infrared output intensity. However, when the distance to the source device 10 is small, using infrared with high output intensity results in a large amount of reflected infrared radiation, making direction estimation difficult. Instead of fixing the infrared output intensity to "high," "medium," or "low," changing the output intensity allows for direction estimation using infrared with high output intensity when the source device 10 is far away, and for appropriate direction estimation using infrared with low output intensity when the source device 10 is nearby. Therefore, the configuration of changing the infrared output intensity is also effective when the source direction estimation device 20 does not estimate distance.

[0060] In addition, when the transmission source device 10 of the present embodiment periodically changes the output intensity of infrared rays, the frequency is set as "weak" infrared rays > "medium" infrared rays > "strong" infrared rays. Therefore, when the transmission source device 10 is close, there is a possibility of an error due to reflection of infrared rays with a large output intensity, but the frequency can be lowered. In the present embodiment, an example of periodically changing the output intensity of infrared rays is given, but the method of changing the output intensity of infrared rays does not have to be periodic.

[0061] (Modification of the third embodiment) In the transmission source device 10 of the third embodiment, the output intensity range for periodically changing the output intensity may be appropriately changed. The transmission source device 10 has a first output intensity range for changing the output intensities R1, R2, R3 (R1 < R2 < R3), a second output intensity range for changing the output intensities R2, R3, R4 (R2 < R3 < R4), and a third output intensity range for changing the output intensities R3, R4, R5 (R3 < R4 < R5). First, in the second output intensity range, the output intensities R2, R3, R4 are periodically changed to output infrared rays.

[0062] When the transmission source direction estimation device 20 receives infrared rays, it determines which output intensity of infrared rays was received from the period. If the output mode of the infrared rays by the transmission source device 10 is set to the output intensity configuration as shown in FIG. 7, for example, the relative intensity of the infrared rays can be known from the number of times the infrared rays are received in one period. The transmission source direction estimation device transmits to the transmission source device 10 which output intensity of infrared rays was received.

[0063] The source device 10 changes the output intensity range based on which of the output intensities R2, R3, and R4 it was able to receive. For example, if the source direction estimation device 20 was able to receive up to output intensity R2, the source device 10 changes the output intensity range from the second output intensity range (R2~R4) to the first output intensity range (R1~R3). If the source direction estimation device 20 was only able to receive output intensity R4, the source device 10 changes the output intensity range from the second output intensity range (R2~R4) to the third output intensity range (R3~R5). However, if the source direction estimation device 20 was able to receive up to output intensity R3, the output intensity range is not changed.

[0064] With this configuration, if the source direction estimation device 20 is able to receive infrared radiation with a relatively low output intensity, it can be assumed that the distance between the source direction estimation device 20 and the infrared emitter is short. Since high output intensity infrared radiation can become noise, shifting the output intensity range to a lower value can prevent the generation of noise. If the source direction estimation device 20 can only receive infrared radiation with a relatively high output intensity within a predetermined output intensity range... In this case, the distance between the source direction estimation device 20 and the infrared emitter is considered to be large. By shifting the output intensity range to a higher value, infrared light can be received even at greater distances, allowing the direction estimation to continue.

[0065] In this embodiment, an example with three output intensity ranges was given, but the output intensity range may have any number of steps.

[0066] (Fourth embodiment) Figure 10A shows the external appearance of robots 100a and 100b equipped with a source direction estimation device. Robots 100a and 100b have the same configuration. Hereafter, when robots 100a and 100b are referred to collectively or when it is not necessary to specify them, they will be referred to as "robot 100". Robot 100 is equipped with a roughly cylindrical horn 102 on its head. The horn 102 contains a direction estimation device 30 that estimates the direction of other robots 100 using infrared light. The robot is also equipped with front wheels 103 and rear wheels 104. The front wheels 103 are a pair, left and right, as shown in Figure 11. The robot can move and rotate using the pair of front wheels 103 and rear wheels 104.

[0067] Figure 10B is a cross-sectional view of the horn 102 of the robot 100b shown in Figure 10A. As shown in Figure 10B, the direction estimation device 30 is equipped with alternatingly arranged infrared light-emitting elements 11a to 11d and light-receiving elements 21a to 21d near the outer edge of its circumference. Focusing only on the infrared light-emitting elements 11a to 11d, the arrangement is the same as that of the infrared light-emitting elements 11a to 11d of the source device 10 described in the first to third embodiments, and focusing only on the infrared light-receiving elements 21a to 21d, the arrangement is the same as that of the infrared light-receiving elements 21a to 21d of the source direction estimation device 20 described in the first to third embodiments.

[0068] As the robot 100 is equipped with both an infrared light-emitting element 11 and an infrared light-receiving element 21, it can emit infrared light into its surroundings and can also receive infrared light emitted from other robots to estimate the position of those other robots 100.

[0069] Figure 11 shows the hardware configuration of robot 100. Robot 100 contains a display device 110, an internal sensor 111, a speaker 112, a communication unit 113, a robot detection unit 114, a posture detection unit 115, a storage device 116, a processor 117, a drive unit 118, and a battery 119 within its housing 101. A direction estimation device 30 is also provided on the horns 102 at the top of the housing 101. Each unit is connected to the others by power lines 120 and signal lines 121. The battery 119 supplies power to each unit via the power lines 120. The battery 119 is, for example, a lithium-ion secondary battery and is the power source for robot 100.

[0070] The drive unit 118 is an actuator that controls the internal mechanism. The drive unit 118 has the function of moving and changing the direction of the robot 100 by driving the front wheels 103 and rear wheels 104. The drive unit 118 also controls the hand 105 via wire 122 to perform actions such as raising the hand 105, shaking the hand 105, and vibrating the hand 105. In addition, the drive unit 118 has the function of controlling the head to change the direction of the head.

[0071] The internal sensor 111 is a collection of various sensors built into the robot 100. Examples of internal sensors 111 include a camera (spherical camera), a microphone array, a distance measuring sensor (infrared sensor), a thermal sensor, a touch sensor, an acceleration sensor, an odor sensor, and so on.

[0072] The communication unit 113 communicates with servers, external sensors, other robots 100, and the user's portable devices. This is a communication module that performs wireless communication with various external devices such as the above. For example, the communication module may be a radio wave communication method such as Wi-Fi (registered trademark) or Bluetooth (registered trademark). The robot detection unit 114 has the function of detecting other robots 100 within a predetermined range (for example, in the same room) by communication using the communication unit 113. The robot detection process of robots 100 by the robot detection unit 114 may, for example, obtain the IP address of other robots 100 present on the Wi-Fi network through the communication unit 113, or it may detect other robots 100 by setting up a server on the LAN that centrally manages robots 100 and accessing the server.

[0073] The posture detection unit 115 has the function of detecting the posture of the robot 100 when the posture of the robot 100 changes, for example, when a user picks up the robot 100. The posture detection unit 115 can detect when the robot 100 is being held by detecting the physical contact when the user picks up the robot 100 using a touch sensor and when the load on the front wheels 103 and rear wheels 104 decreases. When the robot 100 detects that it is being held, the front wheels 103 and rear wheels 104 may be retracted into the housing 101. The storage device 116 consists of non-volatile memory and volatile memory and stores computer programs and various setting information.

[0074] The display device 110 is installed at the position of the robot's eyes and has the function of displaying an image of the eyes. The display device 110 displays an image of the robot's eyes by combining eye parts such as the pupil and eyelids. The display device 110 may also express the gesture of directing its gaze towards another robot 100 by moving its pupil in the direction of another robot 100 estimated by the direction estimation device 30. If external light shines into the eyes, a catchlight may be displayed at a position corresponding to the position of the external light source.

[0075] The processor 117 has the function of operating the robot 100 by controlling the drive unit 118, speaker 112, display device 110, etc., based on sensor information acquired by the internal sensor 111 and various information acquired through the communication unit 113.

[0076] Figure 12 shows a detailed configuration of the direction estimation device 30 mounted on robots 100a and 100b. In Figure 12, only some of the functions of the robot 100 described in Figure 11 are shown. The direction estimation device 30 has four light-emitting elements 11a to 11d, four light-receiving elements 21a to 21d, and a control unit 31 that controls the light-emitting elements 11a to 11d and the light-receiving elements 21a to 21d. The control unit 31 has a light emission control unit 12 that controls the light emission timing and intensity of the light-emitting elements 11, a direction estimation unit 22 that estimates the direction of the source robot based on the received infrared light, and a distance estimation unit 23 that estimates the distance to the source robot. The function of the direction estimation device 30 to receive infrared light and estimate the direction and distance of the source robot of the infrared light based on the received infrared light is the same as that described in the source direction estimation system of the third embodiment described above.

[0077] In this embodiment, the light-emitting elements 11a to 11d of the direction estimation device 30 are each assigned a light-emitting element ID to identify each of them. The light emission control unit 12 then includes the light-emitting element ID that identifies the packet in the infrared packet it outputs.

[0078] In this embodiment, the direction estimation device 30 of robot 100b reads the light-emitting element ID contained in the packet received from the direction estimated to be the source, and transmits the data of the read light-emitting element ID to robot 100a via wireless communication from the communication unit 113. As a result, robot 100a, which receives the light-emitting element ID, can know which of the four light-emitting elements 11 emitted the infrared light that was received. Therefore, robot 100a, which emitted the infrared light, can also determine the direction in which other robots 100b are located. It is possible.

[0079] By enabling the two robots 100a and 100b to understand each other's positions, various interactions can be achieved between the two robots 100a and 100b. For example, robot 100b can perform a process that directs it towards the originating robot 100a by controlling the drive unit 118.

[0080] Furthermore, robots 100a and 100b may be made to act in a way that suggests they are aware of each other. For example, robots 100a and 100b may be made to approach each other in their respective directions. In this case, if the orientation of robots 100a and 100b is controlled so that they are facing each other, it will appear as if robots 100a and 100b are having a rendezvous. Moreover, when robots 100a and 100b meet, they may move together towards the user, play with each other, or chase each other.

[0081] Furthermore, robot 100a or robot 100b may direct its gaze toward the other robot 100 by controlling the eye image displayed on the display device 110. Also, robot 100a can detect the direction of robot 100b by the light-emitting element ID transmitted from robot 100b. However, if robot 100a becomes aware of robot 100b's presence through this wireless communication, it may appear as a sudden movement to the user watching robots 100a and 100b. Therefore, when transmitting the light-emitting element ID via wireless communication, robot 100b may emit a sound to robot 100a through the speaker 112. This allows robot 100a to appear as if it has noticed robot 100b through the sound, even if it is facing robot 100b.

[0082] Furthermore, the direction estimation device 30 may perform a process to estimate the direction of the other robot 100, conditional on the robot detection unit 114 detecting the other robot 100. By not activating the direction estimation device 30 when there is no other robot 100, battery consumption and CPU load can be reduced. Also, since one purpose of estimating the direction of the other robot 100 is to realize cooperative operation with the other robot 100, as described above, the posture detection unit 115 may detect that the robot 100 is being held, etc., and if it is determined that the robot 100 is in a specific state where it is not performing cooperative operation, the direction estimation device 30 may not be activated. The specific state may be, for example, a state in which the user and the robot 100 are interacting, such as when the user is in contact with the robot 100. In addition, even if the robot detection unit 114 detects the other robot 100, the direction estimation device 30 may not be activated if it is received via the communication unit 113 that the other robot 100 is in a specific state. One example of the activation conditions for the direction estimation device 30 is that multiple robots 100 exist in the same space, and that there are other robots 100 that are not in a specific state (i.e., there are two or more robots 100 that are capable of moving). When this condition is met, the direction estimation device 30 may estimate the direction in which the other robots 100 are located.

[0083] In this embodiment, we have taken an example in which robot 100a emits infrared light and robot 100b receives the infrared light to estimate the direction of robot 100a. However, the configurations of robot 100a and robot 100b are identical, and either one may emit infrared light. Therefore, when there are multiple robots 100, it is preferable to control them so that they do not emit infrared light simultaneously. The following methods can be considered for controlling the timing of infrared light emission by multiple robots 100: (1) A method of controlling the order of emission using a communication means other than infrared (Bluetooth® or Wi-Fi). Specifically, one robot 100 sends an emission request, and when permission notifications are received from the remaining robots 100, they start emitting light. . Then, after sending a series of packets, it sends a completion notification. Upon receiving this notification, another robot 100 starts the light emission process. In other words, the other robots 100 wait to start the light emission process until they receive the completion notification. (2) Each robot 100 determines the order in which it will emit light in advance through a means of communication other than infrared, and each robot 100 emits light in that order. (3) The period in which each robot 100 emits infrared light is varied. The amount of noise error is used as a trigger for the variation, and the period is changed when the noise error increases.

[0084] (Fifth embodiment) Next, the object location direction estimation system of this embodiment will be described. As an example of an object, we will use a robot, as described in the fourth embodiment. In other words, the object location direction estimation system is a system in which a robot estimates the direction in which other robots are located. In the fourth embodiment, infrared light was used to estimate the location direction of a robot, but in this embodiment, sensors other than infrared light are also used to estimate the location direction of a robot.

[0085] In the object location direction estimation system of this embodiment, the robot is equipped with various direction estimation systems and position estimation systems, in addition to the infrared source direction estimation system described in the above-described embodiment.

[0086] Figure 13 shows the configuration of the robot presence direction estimation system 50 mounted on the robot. The robot presence direction estimation system 50 comprises a source direction estimation system 52, a sound direction of arrival (DOA) detection system 53, an image recognition device 57, a location information sharing system 60, and a BLE communication unit 64. The source direction estimation system 52 is a system that estimates the direction of the infrared source, and, as in the embodiment described above, comprises a light-emitting element, a light-receiving element, and a control unit.

[0087] The DOA detection system 53 includes a speaker 54 from which a robot emits sound, a microphone array 55 for collecting sound emitted from other robots, and a calculation unit 56 for calculating the direction of other robots (and their speakers 54) based on the data collected by the microphone array 55. The calculation unit 56 estimates the direction of arrival of the sound based on the difference in arrival times of the sound collected by each microphone array 55. It is preferable that the sound emitted by the speaker 54 has a frequency different from that of a human voice. In addition, it is preferable that the sound emitted by the speaker 54 has a frequency different from that of ambient noise.

[0088] The image recognition device 57 includes a camera 58 that takes pictures of the area around the robot, and an image recognition unit 59 that performs image recognition processing on the captured images to extract other robots and estimate the direction of the other robots.

[0089] The location information sharing system 60 has the function of notifying other robots of its own position and the function of acquiring position information notified by other robots and estimating the direction of other robots' presence. The location information sharing system 60 comprises a self-position estimation unit 61, a communication unit 62, and an other robot direction estimation unit 63. The self-position estimation unit 61 estimates the robot's own position using SLAM (Simultaniously Location and Mapping) technology. The communication unit 62 transmits the self-position data estimated by the self-position estimation unit 61 to other robots via the network and receives position data from other robots. The robot and other robots have common map data created by SLAM, and the data of the self's position and the position of other robots are identified on that map. If there is a reference position (for example, a robot charging station) in the map, the position may be notified by relative position from the reference position.

[0090] The BLE communication unit 64 has the function of communicating between robots in accordance with the BLE standard. The BLE communication unit 64 has a distance estimation unit 65 that estimates the distance based on the received BLE radio wave strength.

[0091] The robot presence direction estimation system 50 has an estimation result integration unit 51 that integrates the estimation results of the presence direction of robots acquired by the above-mentioned multiple direction estimation systems to estimate the presence direction of other robots. Various methods are possible for integrating the estimation results. The following describes variations in the integration of estimation results by the estimation result integration unit 51. In the following description, the integration of estimation results from three multiple direction estimation systems will be described: the infrared source direction estimation system 52, the DOA detection device 53, and the image recognition device 57.

[0092] [1st method] The estimation result integration unit 51 acquires data on the estimated direction of other robots and the reliability of those estimation results from the source direction estimation system 52, the DOA detection system 53, and the image recognition device 57. The estimation result integration unit 51 estimates the direction of the object as the estimation result with the highest reliability among the three acquired estimation results.

[0093] Here, reliability is an indicator of the likelihood that the estimated direction is correct. In an infrared source direction estimation device, for example, the infrared reception error rate can be used as an indicator of reliability. The lower the reception error rate, the higher the reliability of the estimation result. By pre-storing the relationship between the reception error rate and reliability in a table, the reliability can be calculated from the reception error rate.

[0094] In the DOA detection system 53, for example, the signal-to-noise ratio (S / N ratio) of the received audio can be used as an indicator of reliability. A higher S / N ratio indicates higher reliability of the estimation result. By pre-storing the relationship between the S / N ratio and reliability in a table, the reliability can be calculated from the S / N ratio.

[0095] In the image recognition device 57, the likelihood of an object being recognized as a robot is used as an indicator of confidence. When recognizing a robot by pattern matching, the likelihood can be calculated using the agreement rate. When detecting a robot using a model trained by a neural network, the likelihood can be defined by the output value at the output layer of the neural network model. By pre-storing the relationship between these likelihoods and confidence levels in a table, the confidence level can be calculated from the likelihood.

[0096] [Second method] The estimation result integration unit 51 prioritizes the direction estimation result from the image recognition device 57. For example, only when the robot is not visible at all, or when there are many objects resembling a robot in the image and the reliability of the robot recognition result is low, does it use the estimation result with the higher reliability among the infrared source direction estimation result or DOA detection result. Generally, if the image recognition device 57 can recognize another robot, its direction of existence can be determined with high accuracy, so the second method is a method that trusts the direction estimation result from the image recognition device 57.

[0097] [3rd method] Figure 14 is a flowchart showing the third method of integrating estimation results by the estimation result integration unit 51. The estimation result integration unit 51 acquires direction estimation results by infrared and direction estimation results by DOA (S20), and determines whether or not there is an overlap between the two acquired estimation directions (S21). If there is an overlap between the two estimation directions (YES in S21), the estimation result integration unit 51 determines the overlapping direction (S22). If there is no overlap (NO in S21), the estimation result integration unit 51 determines the estimation result with higher reliability between the direction estimation results by infrared and the direction estimation results by DOA (S23).

[0098] Next, the estimation result integration unit 51 transmits the determined direction to the image recognition device 57, and the image recognition The camera 58 of the recognition device 57 takes a photograph in that direction (S24). The image recognition device 57 then recognizes the robot from the captured image, estimates the direction in which the robot is located (S25), and passes the estimation result to the estimation result integration unit 51.

[0099] The image recognition device 57 can accurately estimate the direction of presence of the robot if it is present in the captured image, but it cannot determine the direction if the robot is not within the field of view of the camera 58. According to the third method, the direction of the robot is first estimated using omnidirectional infrared or DOA, and then that direction is captured by the camera 58, thereby enabling efficient and highly accurate estimation of the direction of presence.

[0100] [4th method] Figure 15 is a flowchart of the fourth method of integrating estimation results by the estimation result integration unit 51. In the fourth method, the direction of the robot's presence is estimated using the source direction estimation system 52 and the image recognition device 57, without using the DOA detection system 53. The estimation result integration unit 51 acquires the robot's presence direction estimation result from the image recognition device 57 (S30), and then acquires the infrared source direction estimation result from the infrared source direction estimation device (S31).

[0101] Next, the estimation result integration unit 51 determines whether or not there is an overlap between the two estimation directions (S32). If there is an overlap (YES in S32), the estimation result integration unit 51 adopts the robot presence direction estimation result from the image recognition device 57 (S34). If there is no overlap (NO in S32), the estimation result integration unit 51 transmits the estimation result of the infrared source direction estimation to the image recognition device 57, and the camera 58 of the image recognition device 57 takes a picture of that direction (S33). The image recognition device 57 then recognizes the robot from the captured image and estimates the robot's presence direction, and the estimation result integration unit 51 acquires the estimation result (S30).

[0102] By determining whether the robot's direction of presence estimation result obtained by the image recognition device 57 coincides with the estimation result obtained by infrared light, the image recognition device 57 can recognize the correct direction by pointing the camera 58 towards the direction of the infrared light source and taking a new picture if it has mistakenly identified an object other than a robot as a robot.

[0103] [Fifth method] A fifth method of integrating estimation results by the estimation result integration unit 51 will now be described. The source direction estimation system 52, the DOA detection system 53, and the image recognition device 57 each have different characteristics and are suited to certain environments. Specifically, the source direction estimation system 52 estimates the source by receiving infrared light, so the reliability of direction estimation decreases in environments where infrared light is detected at a predetermined frequency or higher. DOA uses sound, so the reliability of direction estimation decreases if ambient noise is loud. The image recognition device 57 analyzes images taken using visible light, so the reliability of direction estimation decreases in dark environments.

[0104] In the fifth method, the robot's direction estimation device decides whether to use each system based on information about the surrounding environment. For detecting the surrounding environment, the infrared light receiving element of the source direction estimation system 52 can be used for infrared light, and the microphone array 55 of the DOA detection system 53 can be used for sound. For ambient brightness, an illuminance sensor can be used.

[0105] An infrared light receiving element determines whether the amount of infrared light received, other than infrared packets transmitted from other robots, is below a predetermined threshold. If it is below the predetermined threshold, the direction estimation result from the source direction estimation system 52 is used; if it exceeds the predetermined threshold, the direction estimation result from the source direction estimation system 52 is not used.

[0106] The microphone array 55 of the DOA detection system 53 determines whether the volume of sound outside the frequency range transmitted from other robots is below a predetermined threshold. If it is below the predetermined threshold, the direction estimation result from the DOA detection system 53 is used; if it exceeds the predetermined threshold, the direction estimation result from the DOA detection system 53 is not used.

[0107] An illuminance sensor determines whether the ambient illuminance is above a predetermined threshold. If it is above the predetermined threshold, the robot's direction of presence estimation result from the image recognition device 57 is used. If it is below the predetermined threshold, the robot's direction of presence estimation result from the image recognition device 57 is not used.

[0108] In the above description, the infrared source direction estimation system 52 was described using the source direction estimation systems of the first to fourth embodiments described above. However, in cases where multiple types of direction estimation systems are used, as in the fifth embodiment, the infrared direction estimation may not follow the configuration of the above embodiments. For example, the direction of reception may be estimated simply by determining which infrared receiver received the infrared light, as in the conventional method. If the reception result fluctuates as a result, the reliability of the infrared direction estimation will be judged to be low, and the estimation result from another direction estimation system will be used, so there is no problem.

[0109] Although the origin direction estimation system and robot equipped therewith of the present invention have been described in detail with reference to embodiments, the present invention is not limited to the embodiments described above.

[0110] In the first embodiment described above, an example was given in which the direction of the source is estimated based on the amount of infrared light received by each photodetector 21 within a predetermined time. However, the direction of the source may also be estimated on the condition that infrared light is received above a predetermined threshold. For example, if three infrared packets are received by any of the photodetectors 21, the direction of reception by that photodetector 21 may be estimated as the direction of the source. However, it is preferable to set a time limit for receiving three packets so that the time required to receive three infrared packets is not too long. For example, the direction of reception may be estimated as the direction of the source on the condition that three infrared packets are received within 1.5 seconds.

[0111] In the first embodiment described above, the direction of the source was estimated as the direction of the maximum amount of infrared light received within a predetermined time. However, as explained in the second embodiment, the direction of the source may be estimated by vector summing the amounts of light received by each of the multiple infrared light receiving elements 21a to 21d.

[0112] In the embodiment described above, an example was given in which the direction of the source is estimated based on infrared light received at the time of source direction estimation. However, the source direction estimation device may estimate the direction of the infrared source based on the current estimation result and past estimation results. By using past estimation results in addition to the current estimation result, a highly accurate estimation can be performed. This is particularly effective when the infrared source is moving. Methods for using past estimation results include, for example, determining the direction of the source as the direction in which the previously estimated direction and the currently estimated direction overlap, or obtaining the movement vector of the source from estimation results at multiple past points in time and correcting the current source direction estimation result.

[0113] Furthermore, in the second embodiment described above, the direction of the source was estimated by vector summing the total number of data received by the multiple photodetectors 21, but the number of received packets may be used instead of the total number of data received.

[0114] Furthermore, in the fourth embodiment described above, an example was given in which, when robot 100b estimates the direction of robot 100a based on infrared reception, it notifies robot 100a of the direction robot 100b is located by wirelessly transmitting a light-emitting element ID. However, if robot 100a and robot 100b have a common coordinate system, information indicating the direction of robot 100a as seen from robot 100b may be notified to robot 100a by wireless communication.

[0115] The above-described source device 10, source direction estimation device 20, and robot 100 are controlled by a program. That is, a program having modules that realize each of the above-described functions such as direction estimation, distance estimation, and light emission control is stored in RAM, ROM, or storage device 116, and the above-described source device 10, source direction estimation device 20, and robot 100 are realized by executing this program by the CPU. Such a program is also included in the scope of this embodiment. [Industrial applicability]

[0116] This invention is useful as a technique for estimating the direction of an infrared source and can be used, for example, for estimating the position of a robot.

Claims

1. Multiple infrared light receiving units with different light receiving directions, A direction estimation unit that estimates the direction of the infrared source based on the amount of light received by each of the infrared light receiving units within a predetermined time period, A source direction estimation device equipped with the following features.

2. The infrared light receiving unit restores the received infrared light into packets according to a predetermined communication protocol. The source direction estimation device according to claim 1, wherein the direction estimation unit estimates the direction of the infrared source based on the number of packets received by each of the infrared light receiving units within a predetermined time.

3. The source direction estimation device according to claim 2, wherein the direction estimation unit estimates the direction of the infrared source based on the number of packets received by each of the infrared light receiving units within a predetermined time, as well as the number of data that did not constitute a packet.

4. The source direction estimation device according to claim 3, wherein the direction estimation unit estimates the direction of the infrared source based on the number of packets and data received by the infrared light receiving unit with the largest number of received packets, and the number of packets and data received by an infrared light receiving unit having a receiving direction adjacent to the receiving direction of the said infrared light receiving unit.

5. Multiple infrared light receiving units with different light receiving directions, A direction estimation unit estimates that the direction of light reception by any infrared light receiving unit is the direction of the infrared light source when the amount of light received by any infrared light receiving unit reaches a predetermined threshold, and the time until the predetermined threshold is reached is within a predetermined time. A source direction estimation device equipped with the following features.

6. The direction estimation unit estimates the direction of the infrared source based on the current estimation result and past estimation results, as described in any one of claims 1 to 5.

7. A source device having an infrared light-emitting section, A source direction estimation device according to any one of claims 1 to 6, A source direction estimation system equipped with the following features.

8. Multiple infrared light-emitting units with different emission directions, A light emission control unit controls the timing of the light emission of each of the infrared light emission units so that they do not overlap, The source device having, A source direction estimation device according to any one of claims 1 to 6, A source direction estimation system equipped with the following features.

9. The source direction estimation system according to claim 7 or 8, wherein the infrared light emitting unit outputs infrared light at a constant period and outputs infrared light with varying output intensity.

10. The source direction estimation system according to claim 9, wherein the infrared light emitting unit emits infrared light with low output intensity at a higher frequency than infrared light with high output intensity.

11. The infrared light emitter changes the output intensity of the infrared rays within a predetermined output intensity range, the source direction estimation device transmits information about the output intensity of the received infrared rays to the infrared light emitter, and the infrared light emitter, based on the output intensity of the infrared rays received by the source direction estimation device, The source direction estimation system according to claim 9 or 10, which modifies the output intensity range.

12. The infrared light emitter transmits a packet containing information indicating the output intensity of the infrared light. The source direction estimation system according to any one of claims 9 to 11, further comprising a distance estimation unit that estimates the distance to the infrared emitter of the source based on information indicating the output intensity contained in the packet received by the infrared receiver.

13. A source direction estimation system comprising a source device and a source direction estimation device according to any one of claims 2 to 4, The aforementioned source device is Multiple infrared light-emitting units with different emission directions, each of which transmits a packet containing the source identifier of the infrared light-emitting unit, A communication unit that communicates with the aforementioned source direction estimation device, Equipped with, The aforementioned source direction estimation device is A source direction estimation system comprising a communication unit that transmits the source identifier contained in the packet used to estimate the source.

14. An infrared light emitter that emits infrared light used for direction estimation, An infrared emitter that emits infrared light containing low-intensity infrared light at a higher frequency than high-intensity infrared light.

15. The infrared light emitter according to claim 14, wherein a packet composed of infrared data includes information indicating the output intensity of the infrared light.

16. An infrared emitter that emits infrared rays, Multiple infrared light receiving units with different light receiving directions, A direction estimation unit that estimates the direction of the infrared source based on the amount of light received by each of the infrared light receiving units within a predetermined time period, A robot equipped with [the following features].

17. The steps include receiving infrared light using multiple infrared light receiving units with different light receiving directions, A step of measuring the amount of light received by each of the infrared light receiving units within a predetermined time period, A step of estimating the direction of the infrared source based on the amount of light received by each of the aforementioned infrared light receiving units, A method for estimating the direction of origin, comprising the following features.

18. A program for estimating the direction of a source based on infrared light received by multiple infrared light receiving units with different receiving directions, wherein the program is configured on a computer connected to the infrared light receiving units. The steps include receiving infrared light from the plurality of infrared light receiving units, A step of measuring the amount of light received by each of the infrared light receiving units within a predetermined time period, A step of estimating the direction of the infrared source based on the amount of light received by each of the aforementioned infrared light receiving units, A program that executes the command.

19. A system for estimating the direction in which an object is located, comprising a source device having an infrared emitter and an audio output device that outputs sound, A source direction estimation device according to any one of claims 1 to 6, which estimates the direction of the source based on infrared radiation transmitted from the source device of the object, A DOA detection device for detecting the direction of arrival of sound output from the sound output device of the aforementioned object, 、 An image recognition device that recognizes the object from an image captured by a camera that photographs the surrounding area and estimates the direction in which the object is located, An estimation result integration unit determines the shooting direction of the camera based on the infrared source direction estimated by the source direction estimation device and the sound arrival direction detected by the DOA detection device, instructs the camera to shoot in that direction, and estimates the direction in which the object exists based on the image captured in the shooting direction estimated by the image recognition device, An object orientation estimation system equipped with the following features.

20. A system for estimating the direction of an object equipped with a source device having an infrared emitter, A source direction estimation device according to any one of claims 1 to 6, which estimates the direction of the source based on infrared radiation transmitted from the source device of the object, An image recognition device that recognizes the object from an image captured by a camera that photographs the surrounding area and estimates the direction in which the object is located, If there is an overlap between the infrared source direction estimated by the source direction estimation device and the direction of the object recognized by the image recognition device, the estimation result from the image recognition device is estimated to be the direction in which the object exists. If there is no overlap, the estimation result integration unit determines the shooting direction of the camera based on the infrared source direction estimated by the source direction estimation device, instructs the camera to shoot in that direction, and estimates the direction estimated by the image recognition device based on the image taken in that shooting direction as the direction in which the object exists. An object orientation estimation system equipped with the following features.

21. A system for estimating the direction of an object, comprising a source device having an infrared emitter and an audio output device that outputs sound, A source direction estimation device according to any one of claims 1 to 6, which estimates the direction of the source based on infrared radiation transmitted from the source device of the object, A DOA detection device for detecting the direction of arrival of sound output from the sound output device of the object, An image recognition device that recognizes the object from an image captured by a camera that photographs the surrounding area and estimates the direction in which the object is located, An estimation result integration unit integrates the infrared source direction estimated by the source direction estimation device, the sound arrival direction detected by the DOA detection device, and the direction of the object recognized by the image recognition device to estimate the direction in which the object exists. Equipped with, The aforementioned estimation result integration unit is an object presence direction estimation system that disables the source direction estimation device in environments where the amount of infrared radiation is above a predetermined threshold, activates the DOA detection device in environments where the ambient noise is above a predetermined threshold, and disables the image recognition device in environments where the brightness is below a predetermined threshold.

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