Communication device and its control method

Abstract

To provide a communication device that operates as an observer device compliant with PAwR, and that can operate appropriately in response to instructions from multiple broadcasting devices. [Solution] The communication device determines whether the difference between the communication timing with the first broadcaster device and the communication timing with the second broadcaster device is less than or equal to a threshold. If the communication device determines that the difference is less than or equal to the threshold, it determines synchronization information for at least one of the first broadcaster device and the second broadcaster device such that the difference is longer than the threshold. The communication device transmits the determined synchronization information to at least one of the first broadcaster device and the second broadcaster device.

Description

Technical Field

[0001] The present invention relates to a communication device and a control method thereof.

Background Art

[0002] As a wireless communication standard that supports connectionless type one-to-many bidirectional communication, Periodic Advertising with Responses (hereinafter, PAwR) defined in Bluetooth (registered trademark) is known (Non-Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In PAwR, an observer device responds to an advertisement signal from a broadcaster device. However, Non-Patent Document 1 does not define the operation when an observer device performs PAwR communication with a plurality of broadcaster devices. Therefore, it may occur that the observer device cannot operate appropriately in response to instructions from a plurality of broadcaster devices.

[0005] In view of such problems of the prior art, in one aspect of the present invention, there is provided a communication device that operates as an observer device compliant with PAwR and can operate appropriately in response to instructions from a plurality of broadcaster devices. [Means for solving the problem]

[0006] In one aspect, the present invention provides a communication device that operates as an observer device in Bluetooth® Periodic Advertising with Responses (PAwR), comprising: determination means for determining whether the difference between the communication timing with a first broadcaster device and the communication timing with a second broadcaster device is less than or equal to a threshold; determination means for determining synchronization information for at least one of the first broadcaster device and the second broadcaster device such that the difference is longer than the threshold time when it is determined that the difference is less than or equal to a threshold; and transmission means for transmitting the determined synchronization information to at least one of the first broadcaster device and the second broadcaster device. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a communication device that operates as an observer device compliant with PAwR and is capable of appropriately responding to instructions from multiple broadcaster devices. [Brief explanation of the drawing]

[0008] [Figure 1] Diagram showing an overview of the communication system according to the embodiment. [Figure 2] Block diagram showing an example of the hardware configuration of the light-emitting device according to the embodiment. [Figure 3] Block diagram showing an example of the hardware configuration of the imaging device according to the embodiment. [Figure 4] Sequence diagrams relating to the operation of each device according to the embodiment. [Figure 5] Timing charts relating to the operation of each device according to the embodiment [Modes for carrying out the invention]

[0009] The present invention will be described in detail below with reference to the attached drawings, based on exemplary embodiments thereof. Note that the following embodiments do not limit the invention to the claims. Furthermore, while multiple features are described in the embodiments, not all of them are essential to the invention, and the multiple features may be combined arbitrarily. In addition, in the attached drawings, the same or similar configurations are given the same reference numeral, and redundant descriptions are omitted.

[0010] In the following, communication compliant with Periodic Advertising with Responses (PAwR), included in Bluetooth® Core Specification Ver. 5.4 and later, will be referred to as PAwR communication. Furthermore, the form in which PAwR communication is performed between an imaging device and a light-emitting device (flash device) will be described.

[0011] However, the present invention can be implemented between any PAwR-enabled electronic devices. Such electronic devices include computer equipment (personal computers, tablet computers, media players, PDAs, etc.), smartphones, smartwatches, game consoles, robots, drones, and dashcams. These are illustrative examples, and the present invention can be implemented with other electronic devices as well.

[0012] Furthermore, this invention is applicable not only to PAwR communication included in Bluetooth® Core Specification Ver. 5.4 and later, but also to devices that perform communication compliant with similar standards to be defined in the future.

[0013] In the following, we will use names that correspond to the function of each device, in accordance with the Bluetooth® standard. • Broadcaster equipment: Equipment that transmits advertising signals (packets). Observer equipment: Equipment that receives advertising signals from broadcasting equipment by scanning.

[0014] The Bluetooth® standard also defines the roles of central device and peripheral device, and devices are permitted to perform multiple of these four roles simultaneously.

[0015] Figure 1 is a block diagram showing an example of a communication system 100 according to this embodiment. The communication system 100 includes a light-emitting device 101, a first imaging device 102, and a second imaging device 103. The number of light-emitting devices and imaging devices may be greater than the number shown. The light-emitting device 101 is located within the communication range of both the first imaging device 102 and the second imaging device 103. In this embodiment, a configuration is assumed in which the operation of the light-emitting device 101 is controlled by PAwR communication from the first imaging device 102 and the second imaging device 103. In PAwR communication, the first and second imaging devices 102 and 103 are broadcaster devices, and the light-emitting device 101 is an observer device.

[0016] (Configuration of the light-emitting device) Figure 2 is a block diagram showing an example of the hardware configuration of the light-emitting device 101. The control unit 201 has one or more processors (hereinafter referred to as CPUs) capable of executing programs, and for example, it reads a program stored in the non-volatile memory of the memory unit 206 into the volatile memory (RAM) of the memory unit 206 and executes it with the CPU. The control unit 201 realizes the functions of the light-emitting device 101 described herein by controlling the operation of each block.

[0017] The memory section 206 includes electrically rewritable non-volatile memory (ROM) and volatile memory (RAM). The ROM stores programs that the control unit 201 CPU can execute, settings, GUI data, etc. The RAM is used to load programs executed by the control unit 201 CPU and to store values ​​necessary during program execution.

[0018] The power control unit 202 includes a battery detection circuit, a protection circuit, a DC-DC converter, an LDO regulator, etc. The power control unit 202 converts the power supply voltage supplied from the power supply unit 203 as necessary and supplies it to the hardware in the light emitting device 101, and detects the amount of power being supplied. The power control unit 202 also detects the presence or absence of battery attachment, and detects the type and remaining amount of the attached battery. When the protection circuit included in the power control unit 202 detects an overcurrent, it cuts off the power supply to suppress damage to the hardware.

[0019] The power supply unit 203 may be a primary battery, a secondary battery, an AC adapter, etc. The type of the power supply unit 203 can be detected by the power control unit 202.

[0020] The operation unit 204 includes a plurality of input devices provided for the user to input instructions to the light emitting device 101. The input devices may be buttons, switches, dials, touch panels, etc. The operation unit 204 may include input devices that do not require physical operations, such as input devices that enable instruction input using voice recognition. <000​​​​​​​​​​​​​In PAwR communication, the transmitting unit 209 transmits response signals and other information via the antenna 211 to external devices that function as broadcasting equipment (in this case, the first imaging device 102 and the second imaging device 103). In addition, in PAwR communication, the receiving unit 210 receives advertisement signals and the like transmitted from broadcasting equipment via the antenna 211.

[0025] (Configuration of the imaging device) The control unit 301 has one or more processors (hereinafter referred to as CPUs) capable of executing programs, and for example, it reads a program stored in the non-volatile memory of the memory unit 306 into the volatile memory (RAM) of the memory unit 306 and executes it with the CPU. The control unit 301 realizes the functions of the first imaging device 102 described herein by controlling the operation of each block.

[0026] The memory unit 306 includes electrically rewritable non-volatile memory (ROM) and volatile memory (RAM). The ROM stores programs that the control unit 301 CPU can execute, setting values, graphical user interface (GUI) data, etc. The memory unit 306 also includes non-volatile memory, such as a memory card, which is used as a recording destination for image data captured by the imaging unit 305. The RAM is used to read programs executed by the CPU of the control unit 301 and to save values ​​necessary during program execution. The RAM is also used as video memory for the display unit 307, as buffer memory for temporarily storing image data output from the imaging unit 305, and as working memory for storing intermediate data in image processing, etc.

[0027] The power control unit 302 includes a battery detection circuit, a protection circuit, a DC-DC converter, an LDO regulator, and the like. The power control unit 302 converts the power supply voltage supplied from the power supply unit 303 as needed and supplies it to the hardware in the first imaging device 102, and also detects the amount of power being supplied. The power control unit 302 also detects whether a battery is installed, and detects the type and remaining charge of the installed battery. The protection circuit in the power control unit 302 cuts off the power supply when it detects an overcurrent, thereby preventing damage to the hardware.

[0028] The power supply unit 303 may be a primary battery, a secondary battery, an AC adapter, etc. The type of power supply unit 303 can be detected by the power control unit 302.

[0029] The operation unit 304 includes a plurality of input devices provided for the user to input instructions to the first imaging device 102. The input devices may be buttons, switches, dials, touch panels, etc. The operation unit 304 includes a shutter release switch, a video recording switch, a shooting mode selection dial for selecting a shooting mode, a menu button, directional keys, a select key, etc. The shutter release switch is a switch for still image recording, and the control unit 301 recognizes the half-pressed state of the shutter release switch as a shooting preparation instruction and the fully pressed state as a shooting start instruction. When the control unit 301 recognizes the shooting preparation instruction, it performs, for example, autofocus detection (AF) and automatic exposure control (AE). When the control unit 301 recognizes the shooting start instruction, it performs still image shooting control, generation of still image data for recording, and recording. Furthermore, when the video recording switch is pressed in the shooting standby state, the control unit 301 recognizes it as a video recording start instruction, and when it is pressed during video recording, it recognizes it as a recording stop instruction. Furthermore, the operation unit 304 may include input devices that do not require physical operation, such as input devices that enable instruction input using voice recognition.

[0030] The imaging unit 305 includes an optical system such as a lens, an image sensor, an A / D converter, etc., and outputs a digital image signal (image data) representing a video or still image. The optical system may have the form of an interchangeable lens that can be attached to and detached from the main body of the first imaging device 102. The optical system may also include an aperture and a mechanical shutter. The optical system includes a movable lens such as a focusing lens and an actuator that drives the movable lens. The operation of the optical system is controlled by the control unit 301.

[0031] The image sensor may be, for example, a known CCD or CMOS color image sensor having a primary color Bayer array color filter. The image sensor has a pixel array in which multiple pixels are arranged in two dimensions, and peripheral circuits for reading signals from each pixel. Each pixel accumulates charge according to the amount of incident light by photoelectric conversion. By reading signals with a voltage corresponding to the amount of charge accumulated during the exposure period from each pixel, a group of pixel signals (analog image signals) representing the subject image formed on the imaging surface by the optical system is obtained. The A / D converter converts the analog image signals into digital image signals (image data). The image data is output to the control unit 301.

[0032] The control unit 301 executes a program on the CPU to apply predetermined image processing to the image data output by the imaging unit 305, generating signals and image data according to their intended use, and acquiring and / or generating various types of information.

[0033] The image processing applied by the control unit 301 may include, for example, preprocessing, color interpolation, correction, detection, data processing, evaluation value calculation, and special effects processing. Preprocessing may include signal amplification, reference level adjustment, and defective pixel correction. Color interpolation is performed when a color filter is provided on the image sensor, and it is a process that interpolates the values ​​of color components that are not included in the individual pixel data that makes up the image data. Color interpolation is also called demosaicing. Correction processing may include white balance adjustment, gradation correction, correction of image degradation caused by optical aberrations in the optical system of the imaging unit 305 (image recovery), correction of the effect of peripheral vignetting in the optical system, and color correction. Detection processes may include detecting feature regions (such as face regions or human body regions) and their movements, as well as recognizing people. Data processing may include processes such as region extraction (trimming), merging, scaling, encoding and decoding, and header information generation (image data file generation). The generation of display image data and recording image data is also included in data processing. The evaluation value calculation process may include processes such as generating signals and evaluation values ​​used for autofocus detection (AF), and generating evaluation values ​​used for automatic exposure control (AE). Special effects processing may include adding blur effects, changing color tones, and relighting. These are merely examples of processes that the control unit 301 can apply, and do not limit the processes that the image processing unit 104 can apply. Furthermore, for some of the image processing described above, instead of the CPU of the control unit 301 executing it, the CPU may use a dedicated hardware circuit such as an ASIC (Application Specific Integrated Circuit).

[0034] The display unit 307 is, for example, a liquid crystal display (LDC) provided on the surface of the housing of the first imaging device 102. The display unit 307 displays various settings of the first imaging device, various information to support shooting, a GUI such as a menu screen, images captured by the imaging unit 305, and images read from the memory unit 306. In the shooting standby state, the first imaging device 102 continuously performs video recording and immediately displays the recorded video on the display unit 307, thereby making the display unit 307 function as an electronic viewfinder (EVF). The operation of making the display unit 307 function as an EVF is called the live view display operation, and the video displayed on the display unit 307 by the live view display operation is called the live view image. The display unit 307 may also be a touch display. The display unit 307 may also have one or more other output devices such as a speaker or LED.

[0035] The wireless communication unit 308 has a transmitting unit 309 and a receiving unit 310, and performs wireless communication with external devices via the antenna 311. In this embodiment, the first imaging device 102 functions as a broadcaster device in PAwR communication, so the wireless communication unit 308 performs communication operations as a broadcaster device.

[0036] In PAwR communication, the transmitter 309 broadcasts the advertised signal via the antenna 311. In addition, in PAwR communication, the receiving unit 310 receives response signals and the like transmitted from the observer device (in this case, the light-emitting device 101) that received the advertised signal, via the antenna 311.

[0037] (Operation of each device) Using Figures 4 and 5, examples of the operation of the light-emitting device 101, the first imaging device 102, and the second imaging device 103 will be explained. Note that the operation described below, mainly focusing on the light-emitting device 101, is actually carried out by the CPU of the control unit 201 executing a program to control the components of the light-emitting device 101 that are related to its operation. Similarly, the operation described below, mainly focusing on the first imaging device 102, is actually carried out by the CPU of the control unit 301 executing a program to control the components of the first imaging device 102 that are related to its operation. The operation described mainly focusing on the second imaging device 103 is similar to the operation mainly focusing on the first imaging device 102.

[0038] Figure 4 is a sequence diagram showing an example of the operation when the light-emitting device 101, the first imaging device 102, and the second imaging device 103 perform PAwR communication. Here, it is assumed that the light-emitting device 101 and the first imaging device 102 are already performing PAwR communication. That is, the light-emitting device 101 is assumed to know the timing at which the first imaging device 102 transmits the advertisement signal, the SUBEVENT to be scanned within the transmission cycle of the advertisement signal, and the response slot to be used.

[0039] In S401, the first imaging device 102, which functions as a broadcaster, transmits an advertisement signal containing PAwR communication information and synchronization information. This advertisement signal does not include any emission instructions for the light-emitting device 101. The PAwR communication information consists of the PA period, the number of subevents, the subevent period, the slot delay time, and the slot period.

[0040] The PA (Periodic Advertising) period is the transmission period of the advertised signal and is equal to the occurrence period of the PAwR event. Up to 128 subevents can be set in one PA period. Within a single subevent period, multiple response slots are defined for observer equipment to use for responses.

[0041] The SUBEVENT number is the number of SUBEVENTs included in each PA cycle (maximum 128).

[0042] The subevent period is the time from the start of one subevent to the start of the next. It is a multiple of 1.25 ms and can range from 7.5 ms to 318.75 ms.

[0043] SLOT delay time is the time from the start of SUBEVENT to the start of the first response slot. It is a multiple of 1.25 ms and can range from 1.25 ms to 317.5 ms.

[0044] The slot period is the time from the start of one response slot to the start of the next response slot. It is expressed as a multiple of 0.125 ms and can range from 0.25 ms to 31.875 ms.

[0045] Synchronization information refers to information used to identify the SUBEVENT that the observer device should scan and the response slot that should be used, and consists of the SUBEVENT number and SLOT number. Synchronization information may also be the PA cycle. The SUBEVENT number is a unique number for each SUBEVENT. The SLOT number is a unique number for each response slot.

[0046] The broadcaster device may have the functionality to connect to the observer device. Once the broadcaster device and the observer device establish a connection, conventional one-to-one connection-based communication (LE ACL communication) via Bluetooth Low Energy connection becomes possible. The observer device may obtain PAwR communication information from the advertised signal or through LE ACL communication with the broadcaster device.

[0047] Furthermore, the broadcaster equipment can select observer equipment to perform PAwR communication with. For example, suppose the communication system 100 has a smartphone or remote control as observer equipment in addition to the light-emitting device 101. In this case, the broadcaster equipment (e.g., the first imaging device 102) can select which of the light-emitting device 101, smartphone, or remote control to communicate with via PAwR.

[0048] In S402, the light-emitting device 101 receives an advertisement signal from the first imaging device 102, which includes PAwR communication information and synchronization information. Then, in a response slot based on the synchronization information, it transmits a response signal via PAwR communication.

[0049] In S403, the second imaging device 103 transmits an advertisement signal via PAwR communication within the communication range of the light-emitting device 101.

[0050] In S404, the light-emitting device 101 receives the advertisement signal transmitted from the second imaging device 103 via PAwR communication.

[0051] In S405, the light-emitting device 101 calculates the communication time (absolute time) with the first imaging device 102 using the communication time calculation unit 207, based on the PAwR communication information and synchronization information included in the advertisement signal received from the first imaging device 102.

[0052] In S406, the light emitter 101 determines, based on the calculated communication time (absolute time), the communication time with the second imaging device 103 to initiate new PAwR communication, such that the communication time with the first imaging device 102 is shifted by a predetermined amount of time or more. The communication time determined here is the SUBEVENT number and SLOT number that identify the response slot to be used for the advertisement signal of the second imaging device 103.

[0053] In addition, the light-emitting device 101 determines the difference in communication time with the first imaging device 102, as well as the response slot that is not being used by other observer devices communicating with the second imaging device 103 via PAwR communication. The light-emitting device 101 transmits the determined SUBEVENT number and SLOT number to the second imaging device 103 via PAwR communication as synchronization information for the light-emitting device 101.

[0054] The predetermined time may be set based on information from an observer device attempting to control its operation using PAwR communication from the imaging device. For example, it may be set based on information such as the maximum emission time of the light emitter 101, the minimum interval or minimum period of emission operation. Specifically, even if emission instructions are received from both the first imaging device 102 and the second imaging device 103, the predetermined time can be set to be greater than or equal to the minimum difference in the timing of receiving emission instructions required to perform the emission operation corresponding to each instruction. Alternatively, the time may be set to maximize the difference between the communication time with the first imaging device 102 and the communication time with the second imaging device 103.

[0055] If changing the communication time for the second imaging device 103 alone does not achieve a delay of more than a predetermined time, the communication time for the first imaging device 102 may also be changed. In other words, the light emitter 101 may also transmit a new synchronization signal to the first imaging device 102 in S406.

[0056] If the observer device (light emitter 101) receives a connection (pairing) request from the broadcaster device (first or second imaging device), it may stop PAwR communication, establish a connection, and then begin one-to-one communication with the broadcaster device. Alternatively, the observer device may ignore the connection request and continue PAwR communication with the broadcaster device.

[0057] In S407, if the second imaging device 103 receives synchronization information from the light-emitting device 101 as a response to the advertisement signal, it updates its own synchronization information with the received synchronization signal.

[0058] In S408, if the first imaging device 102 receives synchronization information from the light-emitting device 101 as a response to the advertisement signal, it updates its own synchronization information with the received synchronization signal.

[0059] In S409, the second imaging device 103 transmits the updated synchronization information to the light-emitting device 101 as an advertisement signal via PAwR communication.

[0060] In S410, the first imaging device 102 transmits the updated synchronization information to the light-emitting device 101 as an advertisement signal via PAwR communication.

[0061] In S411, the light emitter 101 receives advertisement signals containing updated synchronization information from the first imaging device 102 and the second imaging device 103, respectively, and acquires the synchronization information. Here, the light emitter 101 may check whether the synchronization information it transmitted to avoid timing overlap and the acquired synchronization information have been correctly updated. It may then send a response signal via PAwR communication to the first imaging device 102 and the second imaging device 103, respectively, indicating whether the information has been correctly updated or not. If an imaging device has transmitted an incorrectly updated synchronization signal, the light emitter 101 may send the desired synchronization signal again via PAwR communication.

[0062] In S412, when the first imaging device 102 receives an instruction to take a photograph accompanied by the emission of light from the light-emitting device 101, it transmits an advertisement signal containing an emission instruction to the light-emitting device 101 to the SUBEVENT based on the updated synchronization signal via PAwR communication.

[0063] In S413, the light-emitting device 101 scans the advertised signals based on the updated synchronization information and receives a light emission instruction from the first imaging device 102. The light-emitting device 101 then performs the light emission operation.

[0064] In S414, when the second imaging device 103 receives an instruction to take a photograph accompanied by the emission of light from the light-emitting device 101, it transmits an advertisement signal containing an emission instruction to the light-emitting device 101 via PAwR communication to SUBEVENT based on the updated synchronization signal.

[0065] In S415, the light-emitting device 101 scans the advertised signals based on the updated synchronization information and receives a light emission instruction from the second imaging device 103. The light-emitting device 101 then performs the light emission operation.

[0066] Figure 5 is a timing chart corresponding to the operation described in Figure 4. The horizontal axis in Figure 5 is the time axis. The operation and timing of the light-emitting device 101, the first imaging device 102, and the second imaging device 103 are schematically shown on their respective time axes.

[0067] Figure 5 shows an example where the PA cycle of the first imaging device 102 contains 3 subevents (subevent numbers #0 to #2), and the PA cycle of the second imaging device 103 contains 6 subevents (subevent numbers #0 to #5). SLOT #0 indicates the response slot number #0 included in the subevent cycle. For convenience, the SLOT delay time is shown as 0.

[0068] Section 501 indicates PAwR communication between the light-emitting device 101 and the first imaging device 102 in S401 and S402. That is, the light-emitting device 101 receives an advertisement signal containing synchronization information from the first imaging device 102 and transmits a response signal to the first imaging device 102 using a specific response slot. This response signal may include synchronization information desired by the light-emitting device 101 (described later).

[0069] 502 is executed in parallel with 501 and shows the operation of the second imaging device 103 and the light-emitting device 101 in S403 to S406. First, the light-emitting device 101 receives an advertisement signal from the second imaging device 103 (S403, S404). Here, • The time interval identified by the SUBEVENT number and slot number of the synchronization signal included in the advertisement signal received from the second imaging device 103, • The time interval identified by the SUBEVENT number and slot number shown in the synchronization information contained in the advertisement signal received from the first imaging device 102 in 501 Assume that these overlap with each other. Alternatively, assume that the difference in communication timing (start time or end time of the time interval) is less than or equal to a threshold.

[0070] When instructions from the first imaging device 102 and the second imaging device 103 are received at the start of the subevent, if the time interval overlap or the difference in communication timing is below a threshold, it is essentially equivalent to the possibility of receiving light emission instructions simultaneously. This is because the time difference between the timing of actually receiving the instructions and the timing of responding is sufficiently short compared to the shortest light emission period of the light emission device 101, and the time difference does not affect the result that only one of the two light emission instructions can be responded to.

[0071] Therefore, the light-emitting device 101 performs an operation to change at least the synchronization information of the second imaging device 103 (i.e., the timing at which the light-emitting device 101 communicates with the second imaging device 103). As a result, the timing at which the light emission instruction is received can be changed.

[0072] First, the light-emitting device 101 calculates the communication time with the first imaging device 102 using the communication time calculation unit 207 based on the synchronization information and PAwR communication information contained in the advertisement signal received from the first imaging device 102 (S405). Then, the light-emitting device 101 determines a SUBEVENT and slot number that are shifted by a predetermined amount of time or more from the calculated communication time. The light-emitting device 101 transmits the determined SUBEVENT and slot number to the second imaging device 103 via PAwR communication as the synchronization information desired by the light-emitting device 101 (S406). In this case, it is assumed that the light-emitting device 101 also changes the SUBEVENT and slot number for PAwR communication with the first imaging device 102 and transmits them to the first imaging device 102 via PAwR communication as the desired synchronization information.

[0073] When the first imaging device 102 and the second imaging device 103 receive desired synchronization information in response from the light-emitting device 101, they update the synchronization information they hold for the light-emitting device 101 with the received synchronization information (S407, S408).

[0074] 503 indicates that in S411, the light-emitting device 101 is performing PAwR communication with the first imaging device 102 at a timing based on the updated synchronization information. In other words, the advertisement signal transmitted by the first imaging device 102 in S410 includes the updated synchronization information.

[0075] Similarly, 504 indicates that in S411, the light-emitting device 101 is performing PAwR communication with the second imaging device 103 at a timing based on the updated synchronization information. That is, the advertisement signal transmitted by the second imaging device 103 in S409 includes the updated synchronization information. There is a time difference of more than a predetermined time between 503 and 504 on the time axis.

[0076] Section 505 illustrates the operation of the first imaging device 102 and the light-emitting device 101 in S412 and S413. Specifically, the light-emitting device 101 receives a light emission instruction from the first imaging device 102 via an advertisement signal and emits light at, for example, the intensity specified in the light emission instruction.

[0077] Section 506 illustrates the operation of the second imaging device 103 and the light-emitting device 101 in S414 and S415. Specifically, the light-emitting device 101 receives a light emission instruction from the second imaging device 103 via an advertisement signal and emits light at, for example, the intensity specified in the light emission instruction.

[0078] According to this embodiment, when an observer device performs PAwR communication with multiple broadcaster devices, it determines whether the timing difference between the PAwR communication with each broadcaster device is below a threshold. If it is determined that the timing difference is below the threshold, the observer device determines synchronization information such that the timing difference is greater than or equal to a predetermined time, and requests one or more broadcaster devices to update the synchronization information. This makes it possible to operate appropriately in response to instructions from multiple broadcaster devices.

[0079] (Other embodiments) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0080] This embodiment includes the following communication device, a method for controlling the communication device, and a program. (Item 1) A communication device that operates as an observer device in Bluetooth® Periodic Advertising with Responses (PAwR), A determination means for determining whether the difference between the communication timing with the first broadcaster device and the communication timing with the second broadcaster device is below a threshold, If the difference is determined to be less than or equal to a threshold, a determination means for determining synchronization information for at least one of the first broadcaster device and the second broadcaster device such that the difference is longer than the threshold time, A transmission means for transmitting the determined synchronization information to at least one of the first broadcaster device and the second broadcaster device, A communication device characterized by having the following features. (Item 2) The communication device according to item 1, characterized in that the synchronization information includes a SUBEVENT number and a SLOT number. (Item 3) The communication device according to item 1, characterized in that the synchronization information includes a Periodic Advertising (PA) period. (Item 4) The communication device according to any one of items 1 to 3, wherein the communication device is configured to perform a predetermined operation in response to an instruction received from a broadcaster device, and the threshold is set to a time such that the predetermined operation corresponding to each instruction can be performed even if the instruction is received from both the first broadcaster device and the second broadcaster device. (Item 5) The communication device according to any one of items 1 to 4, characterized in that the communication timing is determined according to the response slot used by the communication device for transmission. (Item 6) The communication device according to any one of items 1 to 5, characterized in that the determination means determines the synchronization information for one of the first broadcaster device and the second broadcaster device that will newly perform PAwR communication, and if the difference cannot be achieved with the synchronization information determined for the one, it determines the synchronization information for the other. (Item 7) The communication device according to any one of items 1 to 6, further comprising a verification means for verifying whether the synchronization information contained in the advertisement signal received from at least one of the first broadcaster device and the second broadcaster device has been correctly updated in accordance with the synchronization information transmitted from the transmitting means. (Item 8) The communication device according to item 7, characterized in that the transmission means retransmits the determined synchronization information to at least one of the first broadcaster device and the second broadcaster device that has transmitted an advertisement signal containing incorrectly updated synchronization information. (Item 9) The communication device according to any one of items 1 to 8, characterized in that the communication device is a light-emitting device, and the first broadcaster device and the second broadcaster device are imaging devices. (Item 10) A control method performed by a communication device operating as an observer device in Bluetooth® Periodic Advertising with Responses (PAwR), Determine whether the difference between the communication timing with the first broadcaster device and the communication timing with the second broadcaster device is below a threshold, If the difference is determined to be less than or equal to a threshold, synchronization information is determined for at least one of the first broadcaster device and the second broadcaster device such that the difference is longer than the threshold. The determined synchronization information is transmitted to at least one of the first broadcaster device and the second broadcaster device. A method for controlling a communication device, characterized by having the following features. (Item 11) A program to cause a computer in a communication device operating as an observer device in Bluetooth® Periodic Advertising with Responses (PAwR) to function as one of the means of the communication device described in any one of items 1 to 9.

[0081] The present invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, claims are attached to disclose the scope of the invention. [Explanation of Symbols]

[0082] 100...Communication system, 101...Light-emitting device, 102...First imaging device, 103...Second imaging device, 201, 301...Control unit, 205...Light-emitting unit, 206, 306...Memory unit, 207...Communication time calculation unit, 208, 308...Wireless communication unit, 305...Imaging unit

Claims

1. A communication device that operates as an observer device in Bluetooth® Periodic Advertising with Responses (PAwR), A determination means for determining whether the difference between the communication timing with the first broadcaster device and the communication timing with the second broadcaster device is below a threshold, If the difference is determined to be less than or equal to a threshold, a determination means for determining synchronization information for at least one of the first broadcaster device and the second broadcaster device such that the difference is longer than the threshold time, A transmission means for transmitting the determined synchronization information to at least one of the first broadcaster device and the second broadcaster device, A communication device characterized by having the following features.

2. The communication device according to claim 1, characterized in that the synchronization information includes a SUBEVENT number and a SLOT number.

3. The communication device according to claim 1, characterized in that the synchronization information includes a Periodic Advertising (PA) period.

4. The communication device according to claim 1, wherein the communication device is configured to perform a predetermined operation in response to an instruction received from a broadcaster device, and the threshold is set to a time such that the predetermined operation corresponding to each instruction can be performed even if the instruction is received from both the first broadcaster device and the second broadcaster device.

5. The communication device according to claim 1, characterized in that the communication timing is determined according to the response slot used by the communication device for transmission.

6. The communication device according to claim 1, wherein the determination means determines the synchronization information for one of the first broadcaster device and the second broadcaster device that will newly perform PAwR communication, and if the difference cannot be achieved with the synchronization information determined for the one, it determines the synchronization information for the other device.

7. The communication device according to claim 1, further comprising a verification means for verifying whether the synchronization information contained in the advertisement signal received from at least one of the first broadcaster device and the second broadcaster device has been correctly updated in accordance with the synchronization information transmitted from the transmitting means.

8. The communication device according to claim 7, characterized in that the transmission means retransmits the determined synchronization information to at least one of the first broadcaster device and the second broadcaster device that has transmitted an advertisement signal containing incorrectly updated synchronization information.

9. The communication device according to any one of claims 1 to 8, characterized in that the communication device is a light-emitting device, and the first broadcaster device and the second broadcaster device are imaging devices.

10. A control method performed by a communication device operating as an observer device in Bluetooth® Periodic Advertising with Responses (PAwR), Determine whether the difference between the communication timing with the first broadcaster device and the communication timing with the second broadcaster device is below a threshold, If the difference is determined to be less than or equal to a threshold, synchronization information is determined for at least one of the first broadcaster device and the second broadcaster device such that the difference is longer than the threshold. The determined synchronization information is transmitted to at least one of the first broadcaster device and the second broadcaster device. A method for controlling a communication device, characterized by having the following features.

11. A program for causing a computer in a communication device operating as an observer device in Bluetooth® Periodic Advertising with Responses (PAwR) to function as each of the means of the communication device described in any one of claims 1 to 8.

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