Light-emitting device, light-emitting method and computer-readable medium

Abstract

The present invention provides a light emitting device, a light emitting method and a computer readable medium. The light emitting device includes: a light source; and a processor, which controls the light source to flash in a flashing pattern corresponding to output information containing inherent identification information of the light emitting device, and the processor changes the time interval between each flashing pattern when the light source is flashed in a manner of repeating the flashing pattern.

Description

Technical Field

[0001] The present disclosure relates to a light emitting device, a light emitting method and a computer readable medium. Background Art

[0002] The following system is known, which includes: a light emitting device (also called a tag) attached to an object such as a person or an object, and having a light source that flashes in a flashing pattern corresponding to output information containing inherent identification information; and a camera that is a device for photographing the light of the light sources of a plurality of light emitting devices, and the system identifies each light emitting device (each object) based on the flashing pattern of the plurality of light emitting devices appearing in the image photographed by the camera, and determines the position of each object. Hereinafter, the system is referred to as a light emitting device recognition system.

[0003] Japanese Patent Application Laid-Open No. 2006-153828 discloses a device in which an infrared ray generator irradiates a large number of tags with infrared light having an ID superimposed thereon, and tags having the same ID as the infrared ray emit light.

[0004] The following system is disclosed in Japanese Patent Gazette No. 2005-252399: it includes an optical label with an ID inherent to the flicker of a light source, and a video recorder for photographing the flicker of the light source. The ID is decoded by processing a camera image from the video recorder, and the system tracks the light spot of the optical label contained in the camera image.

[0005] In a system for identifying light-emitting devices, when two or more objects with light-emitting devices are close to each other and the lights of two or more light-emitting devices appear in a narrow area of ​​an image captured by a camera, the flashing patterns of the various light-emitting devices appear mixed in the captured image and the flashing patterns of the various light-emitting devices may not be identified. Summary of the invention

[0006] The present disclosure aims to enable recognition of blinking patterns of the respective light emitting devices from a captured image even when two or more objects with light emitting devices are close to each other and lights of the two or more light emitting devices appear in a narrow area of ​​a captured image of a camera.

[0007] According to the first scheme of the present disclosure, there is provided a light-emitting device, comprising: a light source; and a processor, which controls the light source to flash in a flashing pattern corresponding to output information containing inherent identification information of the light-emitting device, and the processor changes the time interval between each flashing pattern when causing the light source to flash in a manner of repeating the flashing pattern.

[0008] According to a second aspect of the present disclosure, the processor randomly changes the time interval between the flickering patterns.

[0009] According to a third aspect of the present disclosure, the processor sets the time interval to a time n times the blinking time of the blinking pattern, and randomly changes n, where n is a positive integer.

[0010] According to the fourth scheme of the present disclosure, the light-emitting device further includes an acceleration sensor, and when the processor causes the light source to flash in a manner that repeats the flashing pattern, when the acceleration sensor detects that the light-emitting device is stationary, the time interval between each of the flashing patterns is changed, and when the acceleration sensor detects that the light-emitting device is moving, the time interval between each of the flashing patterns is fixed.

[0011] According to a fifth aspect of the present disclosure, the processor extends the time interval when the acceleration sensor detects that the light emitting device is stationary, compared to when the acceleration sensor detects that the light emitting device is moving.

[0012] In the sixth scheme of the present disclosure, the light-emitting device further includes a light detector, and when the processor causes the light source to flash in a manner of repeating the flashing pattern, when the light detector detects light from the light sources of other light-emitting devices, the time interval between each flashing pattern is changed, and when the light detector does not detect light from the light sources of other light-emitting devices, the time interval between each flashing pattern is fixed.

[0013] According to the seventh scheme of the present disclosure, there is provided a computer-readable medium storing a program for causing a computer to execute processing, in which a light source included in a light-emitting device is controlled to flash in a flashing pattern corresponding to output information containing inherent identification information of the light-emitting device, and when the light source is flashed in a manner of repeating the flashing pattern, the time interval between each of the flashing patterns is changed.

[0014] According to the 8th scheme of the present disclosure, there is provided a light-emitting method, wherein a light source included in a light-emitting device is controlled to flash in a flashing pattern corresponding to output information including inherent identification information of the light-emitting device, and when the light source is flashed in a manner of repeating the flashing pattern, the time interval between each of the flashing patterns is changed.

[0015] (Effect)

[0016] According to the first, seventh or eighth embodiment, even when the light of multiple light-emitting devices appears in a narrow area of ​​an image captured by a camera that captures the light of the light sources of multiple light-emitting devices, the flashing pattern of each light-emitting device can be identified.

[0017] According to the second aspect, compared with the case where the time interval between the blinking patterns is changed according to a fixed rule, it is easier to create opportunities to stagger the blinking periods of the blinking patterns of the light emitting devices.

[0018] According to the third aspect, compared with a case where the time interval between each flashing pattern includes a time shorter than the flashing time of the flashing pattern, it is easier to create an opportunity to stagger the flashing periods of the flashing patterns of each light emitting device.

[0019] According to the fourth aspect, when a light emitting device moves and there is a high possibility that the light of the light emitting device in a captured image is separated from the light of other light emitting devices, unnecessary changes in the time intervals between the blinking patterns of the moving light emitting device are prevented.

[0020] According to the fifth aspect, when the light emitting device is stationary and the flickering pattern of the light emitting device appears in the captured image even if the time interval between each flickering pattern of the light emitting device is extended, excessive flickering of the light source of the light emitting device can be suppressed.

[0021] According to the sixth scheme, when the light detector does not detect the light of the light sources of other light-emitting devices and there is a high possibility that the light of the light-emitting device including the light detector is separated from the light of other light-emitting devices in the captured image, unnecessary changes in the time intervals between the flashing patterns of the light-emitting device including the light detector are prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic structural diagram of a tag recognition system according to one embodiment of the present disclosure.

[0023] Figure 2 It is a block diagram of the tag recognition system.

[0024] Figure 3 This is a diagram showing an example of a case where the blinking patterns of two tags overlap in time.

[0025] Figure 4 This is a diagram showing an example of a case where the blinking patterns of two tags overlap in time.

[0026] Figure 5 This is a diagram for explaining that the imaging area per pixel varies depending on the location.

[0027] Figure 6 This is a diagram for explaining that light from a plurality of labels appears in one pixel of a frame image.

[0028] Figure 7 This is a diagram for explaining identification of tags when the blinking patterns of two tags overlap in time.

[0029] Figure 8 This is a diagram for explaining identification of tags when the flashing patterns of two tags overlap in time.

[0030] Fig. 9 This is a diagram showing an example of the time intervals between the blinking patterns of the tags.

[0031] Fig.10 is a block diagram of a tag identification system according to another embodiment.

[0032] Fig.11 This is a diagram showing an example of time intervals between blinking patterns of a tag according to another embodiment.

[0033] Fig.12 is a block diagram of a tag identification system according to yet another embodiment.

[0034] Fig.13 This is a diagram showing an example of time intervals between blinking patterns of a conventional tag. DETAILED DESCRIPTION

[0035] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. The structure described below is an example for explanation and can be appropriately changed according to the specifications of the system, device, and component. In addition, in the case where the following includes multiple embodiments, variations, etc., it is initially assumed that their characteristic parts are appropriately combined and used. The same reference numerals are marked on the same elements in all the drawings, and repeated descriptions are omitted.

[0036] Figure 1 1 is a schematic structural diagram of a tag recognition system 10 according to an embodiment of the present disclosure. The tag recognition system 10 includes: a tag 12 having a light source 18 as a light emitting device, the light source 18 being attached to a moving object such as a person, an animal, or an article, and flashing in a flashing pattern corresponding to output information containing inherent identification information; and a camera 14, which is a device for photographing the light of the light sources 18 of a plurality of tags 12. In addition, the tag recognition system 10 includes a recognition device 16, which identifies each tag 12 based on the light of the light sources 18 of a plurality of tags 12 appearing in an image captured by the camera 14, thereby determining the position of each tag 12. In addition, the number of tags 12 and the number of cameras 14 can be appropriately changed.

[0037] Figure 1An example of using the label identification system 10 for production management of printed materials is shown in FIG. The production process of printed materials includes: a printing step of printing on a medium; a post-processing step of cutting, folding, etc. of the printed result (also referred to as the intermediate material 62) obtained from the printing step; and a delivery step (not shown) of delivering the post-processed result (not shown, also referred to as the intermediate material 62) obtained from the post-processing step. In a printing company, various printed materials are produced, and the content of the processing for each printed material is different. Therefore, the operating procedure instructions are managed together with the intermediate material 62. For example, there is an operator in each process, who receives the operating procedure instructions 60 and the intermediate material 62 from the operator of the previous process, processes the intermediate material 62 according to the operating procedure instructions 60, records the processing completion check in a handwritten manner in the operating procedure instructions 60, and hands over the combination (set) of the operating procedure instructions 60 and the processed intermediate material 62 to the next process. As shown in FIG. Figure 1 As shown, the combination of the work step instruction manual 60 and the intermediate product 62 is sometimes placed in a semi-finished product storage area to wait for processing in the next process.

[0038] The label recognition system 10 is used to determine which process each printed material is currently in or where it is located. Figure 1 As shown, the operation step manual 60 is attached to the label 12, and the light source 18 of the label 12 flashes according to the inherent identification information of the printed matter attached to the label 12. The light of the light source 18 of the plurality of labels 12 is photographed by the camera 14, and the photographed image is sent to the recognition device 16. The recognition device 16 recognizes each printed matter (each intermediate object 62) based on the light of the light source 18 of each label 12 that appears in the photographed image, and determines the position of each printed matter. In addition, the usage of the label recognition system 10 is only an example after all, and the usage of the label recognition system 10 is not limited.

[0039] Figure 2 1 is a block diagram of a tag recognition system 10 according to the present embodiment. The tag recognition system 10 includes a tag 12 as a light emitting device, a camera 14, and a recognition device 16. The light source 18 of the tag 12 is an infrared light emitting element that emits infrared light. The camera 14 is an infrared camera that can capture infrared light from the light source 18 of the tag 12. The camera 14 can capture images at a wide angle of 180 degrees or close to 180 degrees by having a wide-angle lens.

[0040] The tag 12 includes: a light source 18 that flashes using infrared rays according to its own inherent identification information 26; a processor 20 electrically connected to the light source 18; a memory 22 that stores a program 24 for causing the processor 20 to operate and the inherent identification information 26 of the tag 12; and a battery (not shown) that supplies power to each part of the tag 12. The processor 20 reads the program 24 from the memory 22 and operates according to the program 24, thereby functioning as a computer. In particular, the processor 20 operates according to the program 24, thereby functioning as a flashing pattern control unit 30 and a time interval control unit 32, wherein the flashing pattern control unit 30 controls the light source 18 to flash with a flashing pattern corresponding to the output information including the identification information 26, and the time interval control unit 32 controls the light source 18 to flash with a flashing pattern corresponding to the output information including the identification information 26, and the time interval control unit 32 controls the light source 18 to flash repeatedly with a flashing pattern, thereby changing the time interval between each flashing pattern.

[0041] The recognition device 16 is connected to the camera 14 by wire or wirelessly. The recognition device 16 includes a processor 40, a shift register 42, and a memory (not shown) storing a program for causing the processor 40 to operate. The processor 40 obtains the dynamic images sent successively from the camera 14, and stores the image data of the static image obtained by cutting out frames from the dynamic image in the shift register 42. Hereinafter, the image data of the static image obtained by cutting out frames from the dynamic image is referred to as a frame image. The shift register 42 temporarily stores a captured image (also referred to as a captured animation) composed of a large number of frame images captured by the camera 14 in a fixed period in the past. The processor 40 functions as a tag recognition unit 46, which reads the captured image from the shift register 42, interprets the flashing of the light source 18 of the tag 12 appearing in the captured image, thereby recognizing the tag 12, and determining the position of the tag 12 based on the position of the light in the captured image.

[0042] In addition, when the tag recognition system 10 includes a plurality of cameras 14, a common recognition device 16 may be provided for the plurality of cameras 14. In this case, when the tag 12 is photographed by the plurality of cameras 14, the position of the tag 12 may be determined based on the position of each camera 14 and the image captured by each camera 14.

[0043] Next, the blinking pattern of the light source 18 of the tag 12 will be described. Figure 3 This is a diagram showing an example of a case where the flashing patterns 90a and 90b of two tags 12a and 12b do not overlap in terms of time. Figure 4 1 is a diagram showing an example of a situation in which the flashing patterns 90a and 90b of two tags 12a and 12b overlap in time. Figure 3 , 4 In the figure, the left and right directions represent the time axis.

[0044] like Figure 3 As shown, the flickering pattern is composed of a start pattern indicating the start of the flickering pattern and an identification pattern uniquely defined for each tag. The processor 20 of the tag 12 reads the start information (not shown) and the unique identification information 26 of the tag 12 from the memory 22, and encodes them as the start pattern and the identification pattern, respectively. That is, the output information composed of the start information and the identification information 26 is encoded as the flickering pattern.

[0045] The start pattern and the identification pattern are respectively composed of a combination of multiple 0s or 1s. 0 or 1 is represented by a time twice the frame time (also called 2 frame time), and the light source 18 of the tag 12 being off during the 2 frame time represents 0, and the light source 18 of the tag 12 being on during the 2 frame time represents 1. Here, the frame time is the time interval of the frame image obtained by the camera 14. For example, when the camera 14 obtains 30 frame images within 1 second (30 frame images / second), the frame time is approximately 33 milliseconds. The start pattern is composed of a 5-bit bit string common to each tag 12a, 12b, and the identification pattern is composed of an 8-bit bit string that is different in each tag 12a, 12b. The light source of each tag 12a, 12b is controlled to repeatedly send out flashing patterns 90a, 90b.

[0046] The camera 14 captures the flashing of the light source of each tag 12a, 12b, and sends the captured frame images to the recognition device 16 one by one. Figure 3 , 4 As shown, the recognition device 16 includes a shift register 42 for 26 frame images, and the frame images from the camera 14 are successively input into the shift register 42 .

[0047] The recognition device 16 performs an OR operation on two adjacent frame images 80 stored in the shift register 42 to generate bit unit data 43 composed of 13 bit map images 82 as a bit map image 82. Here, the bit map image 82 is, for example, an image of each pixel formed by comparing the brightness values ​​of pixels at the same position in each of the two frame images 80 and using the brightness value of the one with the larger brightness value.

[0048] As described above, the 0 (light off) and 1 (light on) of the flashing pattern of the label are represented by two frames of time respectively and appear in two consecutive frame images. Therefore, the bit unit data 43 composed of the bitmap image 82 obtained by performing an OR operation on the two frame images is confirmed every two frames, so that Figure 7 As shown, a blinking pattern of a label gradually appears in the bit unit data 43. Figure 7The following example is shown in FIG. 1 : In the lower left part, a flashing pattern 90a of the label 12a appears in the bit unit data 43, and in the lower right part, a flashing pattern 90b of the label 12b appears in the bit unit data 43. In addition, each bitmap image 82 constituting the bit unit data 43 is image data of one screen, so the pixel count per one screen is obtained. Figure 7 That kind of code string.

[0049] The tag recognition unit 46 of the recognition device 16 obtains the identification information 26 of each tag 12a, 12b by decoding the bit unit data 43, and recognizes each tag 12a, 12b. Then, the tag recognition unit 46 determines the position of each tag 12a, 12b based on the position of the light source of each tag 12a, 12b appearing in the frame image.

[0050] However, in a frame image, the light from the light sources of multiple tags may overlap. Figure 5 : The following situation is shown in FIG. 1 : Now, a camera 14 is set at a predetermined height with respect to a certain plane 70, and the camera 14 captures the light from the light sources 18a and 18b of two labels (the outline of the labels is not shown) placed on the plane 70. Near the center of the lens of the camera 14 (the portion that captures the portion directly below the camera 14), the distance from the camera 14 to the plane 70 is short, and therefore, the capturing range on the plane 70 for each angle α of the field of view of the camera 14 becomes narrower. On the other hand, near the end of the lens of the camera 14 (the portion that captures the portion on the end side away from the camera 14), the distance from the camera 14 to the plane 70 is long, and therefore, the capturing range on the plane 70 for each angle α of the field of view of the camera 14 becomes wider. This means that the capturing area per pixel of the imaging element of the camera 14 becomes smaller near directly below the camera 14, and becomes larger on the end side away from the camera 14.

[0051] Therefore, if Figure 5 As shown, for example, when the light sources 18a and 18b of two tags are located close to each other and far from the camera 14, the camera 14 is more likely to capture the light after the light of the two light sources 18a and 18b overlaps. Figure 6 As shown, in each frame image 80 constituting the captured image 84 of the camera 14, light obtained by overlapping the lights of the two light sources 18a and 18b appears in one pixel 76, and each tag cannot be identified.

[0052] In addition, in the frame image 80, in addition to the case where the lights of the two light sources 18a and 18b appear overlapping, there are also cases where the lights of the two light sources 18a and 18b appear in adjacent pixels, and there are cases where the lights of the two light sources 18a and 18b appear in multiple pixels and parts of these pixels appear overlapping or close to each other. In this case, for example, when processing is performed in pixel units (for example, 8×8 pixel units or 32×32 pixel units, etc.) obtained by summing the frame image 80, each label may not be recognized.

[0053] In addition, the above assumes that there are multiple tags on the end side away from the camera 14. However, when there are multiple tags directly below the camera 14, when the number of pixels of the imaging element of the camera 14 is low (low resolution) or the tags are very close to each other, the light of the multiple tags in the frame image 80 also appears in the same pixel or close pixels, which may cause the same problem.

[0054] Here, if Figure 3 As shown in FIG. 1 , if the time difference Tdif between the flashing patterns 90a and 90b of the two tags 12a and 12b is 1 bit (2 frame times) or more, even if the two tags 12a and 12b are located close to each other and the light from the two light sources 18a and 18b appears in the same pixel of the frame image, the tags 12a and 12b can be identified. Figure 7 As shown, when the pixel where the light from the two light sources 18a and 18b appears in the bit unit data 43 is checked every two frames, a flashing pattern 90a ( Figure 7 The symbol surrounded by dotted lines at the lower left of the label 12b appears after a certain period of time. Figure 7 Therefore, each tag 12a, 12b can be identified.

[0055] On the other hand, Figure 4 As shown, when the flashing patterns 90a, 90b of the two tags 12a, 12b overlap in time, that is, when the time difference Tdif between the flashing patterns 90a, 90b of the two tags 12a, 12b is negative, when the two tags 12a, 12b are positioned close to each other and the light of the two light sources 18a, 18b appears in the same pixel of the frame image, each tag 12a, 12b cannot be identified. Figure 8 It is confirmed every 2 frames. Figure 4 The timing of the flashing patterns 90a and 90b shown in FIG. 4 shows the change in the code string when the pixels of light from the two light sources 18a and 18b appear in the bit unit data 43. Figure 8 As shown, in the lower left dotted frame, the flashing pattern 90a of the tag 12a should appear, but the third bit from the right shown as "error" is due to Figure 4 The first 1 of the start pattern "10001" of the tag 12b shown in the figure is replaced from 0 to 1, and the flashing pattern 90a of the tag 12a does not appear. In addition, the flashing pattern 90b of the tag 12b should have appeared in the dotted line frame on the lower right, but the second and third bits from the left shown as "error" are replaced due to Figure 4 The last 11 of the identification pattern "01001011" of the tag 12a shown is replaced from 00 to 11, so the blinking pattern 90b of the tag 12b does not appear. Therefore, the tags 12a and 12b cannot be identified.

[0056] In the prior art, Figure 4 The temporal overlap of the flashing patterns 90a, 90b of the two tags 12a, 12b shown continues for a long time. Fig.13 As shown, in the prior art, when each tag 12a, 12b repeatedly sends out the blinking patterns 90a, 90b, the blinking time Tpat of each blinking pattern 90a of the tag 12a is the same as the blinking time Tpat of each blinking pattern 90b of the tag 12b, and the time interval Tint of each blinking pattern 90a of the tag 12a is the same as the time interval Tint of each blinking pattern 90b of the tag 12b. Therefore, over a long period of time, the blinking pattern 90a of the tag 12a and the blinking pattern 90b of the tag 12b repeatedly overlap in time.

[0057] Therefore, the tag 12 of this embodiment has a mechanism that operates in a manner that ensures that the flashing pattern of each tag 12 can be recognized from the captured image even when the light of two or more tags 12 appears in a relatively narrow area of ​​the captured image of the camera 14. This is achieved as follows: the processor 20 ( Figure 2 Reference) functions as the time interval control unit 32 to change the time interval Tint between each flashing pattern when the light source 18 flashes in a manner of repeatedly sending a flashing pattern.

[0058] Therefore, if Fig. 9 As shown, the opportunity of staggering the flashing periods Tpat of the flashing patterns 90a, 90b of the multiple tags 12a, 12b is created, thereby ensuring the opportunity of identifying the flashing patterns 90a, 90b of the tags 12a, 12b from the captured image even when the light of the multiple tags 12a, 12b appears in a narrow area of ​​the captured image of the camera 14.

[0059] Furthermore, when the time interval control unit 32 of the tag 12a (12b) flashes the light source 18 in a manner of repeatedly sending out the flashing pattern 90a (90b), the time interval Tint between each flashing pattern 90a (90b) may be randomly changed. In this way, compared with the case where the time interval Tint between each flashing pattern 90a (90b) is changed according to a fixed rule, it is easier to create an opportunity for the flashing periods Tpat of the flashing patterns 90a and 90b of each tag 12a and 12b to stagger with each other.

[0060] In addition, the time interval control unit 32 of the tag 12a (12b) may also set the time interval Tint between each flashing pattern 90a (90b) to a time n times (where n is a positive integer) the flashing time Tpat of the flashing pattern 90a (90b), and randomly change n. In this way, it is easier to create an opportunity for the flashing periods Tpat of the flashing patterns 90a, 90b of the tags 12a, 12b to stagger with each other, compared to a case where the time interval Tint between each flashing pattern 90a (90b) includes a time shorter than the flashing time Tpat of the flashing pattern 90a (90b).

[0061] Next, a tag recognition system 10A according to another embodiment will be described. Fig.10 is a block diagram of a tag recognition system 10A according to another embodiment. Fig.10 The block diagram is similar to the one described above. Figure 2 The difference between the block diagram is that Fig.10 In the embodiment, the tag 12A includes an acceleration sensor 50. The acceleration sensor 50 is electrically connected to the processor 20 and outputs a detection signal to the processor 20.

[0062] In this embodiment, the processor 20 of the tag 12A functions as a time interval control unit 32, and when the light source 18 is flashed in a repeated flashing pattern, the time interval Tint between each flashing pattern is changed when the acceleration sensor 50 detects that the tag 12A is stationary, and the time interval Tint between each flashing pattern is fixed when the acceleration sensor 50 detects that the tag 12A is moving. Fig.111 is a diagram showing an example of the time interval Tint of each flashing pattern 90a, 90b, 90c of the tags 12Aa, 12Ab, 12Ac of the present embodiment. The tags 12Aa and 12Ab are tags detected as stationary by the acceleration sensor 50, and the tag 12Ac is a tag detected as moving by the acceleration sensor 50. When the tag 12Ac moves, there is a high possibility that the light of the tag Ac in the image captured by the camera is separated from the light of the other tags 12Aa and 12Ab, and even if the time interval Tint between each flashing pattern 90c of the tag 12Ac is not changed, there is a high possibility that the flashing pattern of the tag 12Ac can be identified from the captured image. Therefore, if it is configured as in the present embodiment, it is possible to prevent the time interval Tint between each flashing pattern 90c of the moving tag 12Ac from being changed unnecessarily.

[0063] In addition, Fig.10 In the embodiment, the time interval control unit 32 may extend the time interval Tint between each flashing pattern when the acceleration sensor 50 detects that the tag 12A is stationary, compared to when the acceleration sensor 50 detects that the tag 12A is moving. Fig.11 The action of this structure is reflected in . In the case where the tag 12Ac is moving, if the time interval Tint between each flashing pattern 90c is extended, there is a concern that the tag 12Ac disappears from the camera's shooting range before the light of the tag 12Ac appears in the camera's captured image, and the tag 12Ac cannot be tracked. On the other hand, in the case where the tags 12Aa and 12Ab are stationary, even if the time interval Tint between each flashing pattern 90a and 90b is long, the flashing pattern reliably appears in the camera's captured image, so there is no such concern for the moving tag 12Ac. Therefore, by extending the time interval Tint between each flashing pattern 90a and 90b of the stationary tags 12Aa and 12Ab, it is possible to suppress excessive flashing of the light source 18 of the tags 12Aa and 12Ab. In addition, by extending the time interval Tint between each flashing pattern 90a and 90b of the tags 12Aa and 12Ab, the flashing pattern 90a of the tag 12Aa and the flashing pattern 90b of the tag 12Ab are not easily overlapped in time. Thus, even if the lights of a plurality of tags 12Aa and 12Ab appear in a narrow area of ​​the captured image of the camera 14, the opportunity to recognize the blinking patterns 90a and 90b of the tags 12Aa and 12Ab from the captured image is reliably ensured.

[0064] Next, a tag recognition system 10B according to still another embodiment will be described. Fig.12 It is a block diagram of a tag recognition system 10B according to still another embodiment. Fig.12 The block diagram is similar to the one described above. Figure 2 The difference between the block diagram is that Fig.12 In the embodiment, the tag 12B includes a light detector 52. The light detector 52 is electrically connected to the processor 20 and outputs a detection signal to the processor 20.

[0065] In this embodiment, the processor 20 of the tag 12B functions as a time interval control unit 32, and when the light source 18 is flashed in a repeated flashing pattern, the time interval Tint between each flashing pattern is changed when the light detector 52 detects the light of the light source 18 of other tags, and the time interval Tint between each flashing pattern is fixed when the light detector 52 does not detect the light of the light source 18 of other tags. In the case where the light detector 52 of the tag 12B does not detect the light of other tags, there is a high possibility that the light of the tag 12B in the captured image of the camera is separated from the light of other tags, and even if the time interval Tint between each flashing pattern of the tag 12B is not changed, there is a high possibility that the flashing pattern of the tag 12B can be recognized from the captured image. Therefore, according to the above structure, it is possible to prevent the time interval Tint between each flashing pattern of the tag 12B from being changed unnecessarily when the light detector 52 of the tag 12B does not detect the light of other tags.

[0066] In each embodiment described above, the light source 18 of the tag emits infrared light, and the camera is an infrared camera that captures the infrared light. However, the light source 18 of the tag 12 may also emit visible light (a type of electromagnetic wave) instead of infrared light, and the camera may capture the visible light.

[0067] In addition, the flashing pattern emitted by the light source of the tag may be a method of following the recognition pattern with an ending pattern, or a method of adding a pattern for error detection and correction, etc., and the method of the flashing pattern is not limited.

[0068] Furthermore, in each of the embodiments described above, the tag recognition unit 46 of the recognition device 16 recognizes the tag 12 from the captured image and determines the position of the tag 12. However, the tag recognition unit 46 may be a method of recognizing the tag 12 from the captured image but not determining the position of the tag 12. In this specification, "recognition of a tag (light-emitting device)" includes recognizing a tag based on a captured image, but does not include determining the position of the tag. The "tag recognition system" also includes a system that recognizes a tag (light-emitting device) from a captured image but does not determine the position of the tag (light-emitting device).

[0069] In addition, the processors of the above-mentioned embodiments operate according to the program, but the processor may also be in other forms. The processor refers to a broad processor, including general-purpose processors (such as CPU: Central Processing Unit, etc.), special-purpose processors (such as GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic devices, etc.).

[0070] Furthermore, the operations of the processors in the above-described embodiments may be performed not by a single processor but by cooperation of a plurality of processors located in physically separate locations.

Claims

1. A light emitting device, comprising: light source; as well as a processor that controls the light source to flash in a flashing pattern corresponding to output information including inherent identification information of the light emitting device, When the processor causes the light source to flash in a manner of repeating the flashing pattern, the processor changes the time interval between each of the flashing patterns. The light emitting device further comprises an acceleration sensor, When the processor causes the light source to flash in a manner that repeats the flashing pattern, the processor changes the time interval between each flashing pattern when the acceleration sensor detects that the light-emitting device is stationary, and fixes the time interval between each flashing pattern when the acceleration sensor detects that the light-emitting device is moving.

2. The light emitting device according to claim 1, wherein: The processor randomly changes the time interval between the flashing patterns.

3. The light emitting device according to claim 2, wherein: The processor sets the time interval to n times the flashing time of the flashing pattern, and randomly changes n, where n is a positive integer.

4. The light emitting device according to claim 1, wherein: The processor extends the time interval when the acceleration sensor detects that the light emitting device is stationary, compared to when the acceleration sensor detects that the light emitting device is moving.

5. A computer-readable medium storing a program causing a computer to execute a process in which: performing control to cause a light source included in a light emitting device to flash in a flashing pattern corresponding to output information including inherent identification information of the light emitting device, When the light source is flashed in a manner of repeating the flashing pattern, the time interval between each of the flashing patterns is changed, When the light source is caused to flash in a manner of repeating the flashing pattern, the time interval between each flashing pattern is changed when the acceleration sensor included in the light-emitting device detects that the light-emitting device is stationary, and the time interval between each flashing pattern is fixed when the acceleration sensor detects that the light-emitting device is moving.

6. A method for emitting light, wherein: performing control to cause a light source included in a light emitting device to flash in a flashing pattern corresponding to output information including inherent identification information of the light emitting device, When the light source is flashed in a manner of repeating the flashing pattern, the time interval between each of the flashing patterns is changed, When the light source is caused to flash in a manner of repeating the flashing pattern, the time interval between each flashing pattern is changed when the acceleration sensor included in the light-emitting device detects that the light-emitting device is stationary, and the time interval between each flashing pattern is fixed when the acceleration sensor detects that the light-emitting device is moving.

Images