Light source control device and light source system

Abstract

This light source control device comprises: a signal reception unit (11) that receives a video signal output by an imaging device; a signal synchronization unit (12) that extracts a frame synchronization signal from the received video signal; an offset adjustment unit (13) that applies an offset time to the extracted frame synchronization signal to generate an offset synchronization signal; and at least one light emission control unit (14) that generates a light emission control signal for determining a light emission timing and a light emission period, on the basis of the generated offset synchronization signal, and causes a light emitting element provided to at least one light source to intermittently emit light in accordance with the generated light emission control signal.

Description

Light source control device and light source system

[0001] The present disclosure relates to light source control technology.

[0002] When capturing an image of a subject using a camera, an auxiliary light source may be used in addition to the light source provided in the camera to improve the quality of the captured image. A commonly used auxiliary light source is a fixed-light source. For example, Patent Document 1 discloses a technique for forcibly emitting auxiliary light when the brightness of the subject is below a predetermined level (see Figures 5 and 6 of Patent Document 1).

[0003] Japanese Patent Application Publication No. 1-217331

[0004] The technique disclosed in Patent Document 1 has a problem in that heat generated by the auxiliary light source outside of the exposure time increases.

[0005] The present disclosure has been made to solve such problems, and aims to provide a light source control technology that can suppress heat generation.

[0006] One aspect of a light source control device according to an embodiment of the present disclosure includes a signal receiving unit that receives a video signal output by an imaging device, a signal synchronization unit that extracts a frame synchronization signal from the received video signal, an offset adjustment unit that adds an offset time to the extracted frame synchronization signal to generate an offset synchronization signal, and at least one light emission control unit that generates a light emission control signal that determines a light emission timing and a light emission period based on the generated offset synchronization signal, and causes a light emitting element included in at least one light source to emit light intermittently in accordance with the generated light emission control signal.

[0007] According to the light source control device according to the embodiment of the present disclosure, the light source emits light intermittently, thereby suppressing heat generation.

[0008] 4A to 4C are timing charts illustrating the operation of the light source system according to Embodiment 1. FIG. 4A is a timing chart showing the exposure time of a camera. FIG. 4B is a timing chart showing the operation of an auxiliary light source as a comparative example. FIG. 4C is a timing chart showing ...2. FIG. 7A to 7C are timing charts illustrating the operation of the light source system according to Embodiment 2. FIG. 7A is a timing chart showing the exposure time of a camera. FIG. 7B is a timing chart showing the operation of a certain light source among the plurality of light sources included in the light source system according to Embodiment 2. FIG. 4C is a timing chart showing the operation of another light source among the plurality of light sources included in the light source system according to Embodiment 2. FIG Figures 9A to 9C are timing charts for explaining the operation of the light source system according to embodiment 3. Figure 9A is a timing chart showing the exposure time of a camera. Figure 9B is a timing chart showing the operation of a light source among the multiple light sources provided in the light source system according to embodiment 3. Figure 9C is a timing chart showing the operation of another light source among the multiple light sources provided in the light source system according to embodiment 3. Figures 10A to 10B are timing charts for explaining the operation of a light source system according to a modified example. Figure 10A is a timing chart showing the exposure time of a camera. Figure 10B is a timing chart showing the operation of a light source provided in the light source system according to a modified example.

[0009] Various embodiments of the present disclosure will be described in detail below with reference to the drawings. In the drawings, identical or similar parts are designated by identical or similar reference numerals, and redundant explanations of such parts will be omitted. In addition, in this disclosure, the term "or" is used to mean an inclusive logical OR unless otherwise specified.

[0010] Embodiment 1. <Configuration of Light Source Control System> A light source control device 10 and a light source system 1 according to a first embodiment of the present disclosure will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the light source system 1 is a light source system for assisting a camera 20. The camera 20 is an example of an imaging device. The imaging device may be any device that has the function of capturing temporally consecutive frame images, and the specific name of the imaging device does not matter. The light source system 1 includes a light source control device 10 and a light source 30. The light source control device 10 controls illumination by the light source 30. The light source 30 is a light source that includes a plurality of light-emitting elements, such as LEDs (Light Emitting Diodes).

[0011] 3, when an object is photographed using the camera 20, the camera 20 transmits a video signal, and the light source control device 10 receives the video signal from the camera 20. The light source control device 10 controls illumination by the light source 30 based on the received video signal. The camera 20 and the light source control device 10, and the light source control device 10 and the light source 30 are connected by wire or wirelessly so as to be able to send and receive signals.

[0012] Here, to better understand the operation of light source system 1, the operation will be described with reference to Figures 4A to 4C. Figures 4A to 4C are timing charts for explaining the operation of light source system 1 according to embodiment 1. Figure 4A is a timing chart showing the exposure time of camera 20. Figure 4B is a timing chart showing the operation of an auxiliary light source as a comparative example. Figure 4C is a timing chart showing the operation of light source system 1 according to embodiment 1.

[0013] Generally, when capturing an image of a subject using a camera, an auxiliary light source may be used in addition to the light source provided in the camera to improve the quality of the captured image. As such an auxiliary light source, a constant-light auxiliary light source, that is, an auxiliary light source that continuously emits a constant amount of light, as shown in Figure 4B, is widely used.

[0014] However, as shown in Fig. 4A, the exposure time of the camera is only a part of the video frame (frame period), and the light from the assist light source does not contribute to the image outside the exposure time. Therefore, the assist light source of the comparative example shown in Fig. 4B has the problem that heat generated by the assist light source outside the exposure time increases.

[0015] As shown in Figure 4C, emitting light from the auxiliary light source only during the exposure time enables illumination with high power efficiency and reduced heat generation. Generally, the rise time of LEDs widely used for illumination is on the order of microseconds at the latest, which allows for sufficiently fast on / off operation for frame rates such as 60 fps. Therefore, it is possible to perform the operation shown in Figure 4C. The light source control device 10 according to the first embodiment is a device that enables the operation shown in Figure 4C.

[0016] <Configuration of Light Source Control Device> Referring again to FIG. 1 , the configuration of the light source control device 10 will be described. As shown in FIG. 1 , the light source control device 10 includes, as an example, a signal receiving unit 11, a signal synchronizer 12, an offset adjuster 13, and an emission control unit 14. Specifically, the light source control device 10 includes the signal receiving unit 11 that receives a video signal output by the camera 20, the signal synchronizer 12 that extracts a frame synchronization signal from the received video signal, the offset adjuster 13 that generates an offset synchronization signal by adding an offset time to the extracted frame synchronization signal, and the emission control unit 14 that generates an emission control signal that determines an emission timing and an emission period based on the generated offset synchronization signal and causes a light-emitting element included in the light source 30 to emit light intermittently in accordance with the generated emission control signal. Transmission and reception of signals or data between different functional units may be performed directly between the different functional units or indirectly via a control unit (not shown).

[0017] 1, the light source control device 10 may also include an exposure recognition unit 15. The exposure recognition unit 15 is a functional unit that measures the exposure of the subject represented in the received video signal. When the light source control device 10 includes the exposure recognition unit 15, the light emission control unit 14 causes the light emitting element of the light source 30 to emit light intermittently so that the exposure measured by the exposure recognition unit 15 becomes greater. The configuration of the light source control device 10 will be described in more detail below in separate paragraphs.

[0018] (Signal Receiving Unit) The signal receiving unit 11 receives a video signal from the camera 20. The signal receiving unit 11 is an interface compatible with image communication standards such as HDMI (High-Definition Multimedia Interface) (registered trademark) or DisplayPort (registered trademark). The video signal is a digital signal for displaying video in which frame images are updated at a predetermined frame period, for example, 60 frames per second. The signal receiving unit 11 supplies the received video signal to the signal synchronizing unit 12.

[0019] (Signal Synchronization Unit) The signal synchronization unit 12 extracts a frame synchronization signal indicating the beginning of a frame from the video signal received from the signal reception unit 11. The signal synchronization unit 12 supplies the extracted frame synchronization signal to the offset adjustment unit 13.

[0020] (Offset Adjustment Unit) The offset adjustment unit 13 receives the frame synchronization signal extracted by the signal synchronization unit 12. The frequency of the frame synchronization signal matches the frequency of the camera 20, but contains a phase shift due to signal delay of the video signal. Therefore, the offset adjustment unit 13 adds an offset time to the frame synchronization signal to compensate for the phase shift, thereby generating an offset frame synchronization signal (hereinafter, sometimes simply referred to as an "offset synchronization signal") that is offset by the offset time. When the light-source control device 10 is started, the offset time may be set to 0. The offset adjustment unit 13 supplies the generated offset synchronization signal to the light-emission control unit 14. Note that the signal delay includes signal processing within the camera 20, cable transmission delay in the cable connecting the camera 20 and the light-source control device 10, processing delay in the signal receiving unit 11, etc. However, since the total amount of these delays is considered to be constant, once the offset time is determined, it can be considered to be constant.

[0021] (Light Emission Control Unit) The light emission control unit 14 generates a light emission control signal that determines the light emission timing that determines the start of light emission and the light emission time that determines the period of light emission, based on the offset synchronization signal received from the offset adjustment unit 13. The light emission control unit 14 controls the light emission by the light source 30 using the generated light emission control signal. The light emission timing may be the same as the offset synchronization signal. The light emission time is set to a period shorter than the frame period. For example, as shown in FIG. 4C , the light emission control unit 14 sets the light emission time to a period equal to the exposure time obtained from the video signal.

[0022] By causing the light emitting elements of light source 30 to emit light intermittently so that they emit light only during the exposure time of camera 20 and are turned off at other times, it is possible to reduce power consumption or the amount of heat generated. In particular, when the amount of heat generated restricts the output of light source 30, the light emission intensity can be increased compared to continuous emission according to the first embodiment.

[0023] 1, the light source control device 10 may have an exposure recognition unit 15 as an additional functional unit. When the light source control device 10 has the exposure recognition unit 15, the offset adjustment can be automated by feeding back, to the exposure recognition unit 15, information on the light emission timing from the offset adjustment unit 13 and information on the light emission timing from the light emission control unit 14.

[0024] If the light source control device 10 has an exposure recognition unit 15, the exposure recognition unit 15 also receives a video signal from the signal receiving unit 11. The exposure recognition unit 15 recognizes the video signal and measures the exposure of the subject. The exposure value can be measured from the luminance value of the subject included in the video signal according to a known algorithm.

[0025] When measuring the exposure of a subject, the exposure recognition unit 15 performs an increase / decrease determination to gradually increase / decrease the offset time within the range of the frame period, and the offset adjustment unit 13 adds (increases / decreases) the offset time to the frame synchronization signal in accordance with the increase / decrease determination by the exposure recognition unit 15. By gradually increasing / decreasing the offset time within the range of the frame period in this manner, the exposure recognition unit 15 measures the range in which the exposure is greatest. The range in which the exposure is greatest is estimated to be a value in which the phase of the frame synchronization signal and the phase of the light source 30 are synchronized.

[0026] In this way, light emission may be controlled not so as to maximize exposure, but so as to increase exposure.

[0027] Furthermore, the exposure recognition unit 15 determines whether to increase or decrease the light emission time, and the light emission control unit 14 performs light emission control to increase or decrease the light emission time in accordance with the increase or decrease determination of the exposure recognition unit 15. By increasing or decreasing the light emission time in this manner, the exposure recognition unit 15 determines the minimum value of the light emission time that maximizes the exposure. By determining the minimum value of the light emission time, the exposure time can be estimated.

[0028] Furthermore, in order to keep exposure constant against jitter and errors, light may be emitted before and after the estimated exposure time, or for a period longer than the exposure time. If the exposure time and frame period are known, these may be controlled using these known values. Furthermore, the light emission time may be set shorter than the exposure time, and if a light emission time is set in the latter half of the exposure time, an image resembling an afterimage can be obtained.

[0029] Next, an example of the hardware configuration of the light source control device 10 will be described with reference to Figures 2A and 2B. Each function of the light source control device 10 is realized by a processing circuitry. The processing circuitry may be a dedicated processing circuit 100a as shown in Figure 2A, or a processor 100b that executes a program stored in a memory 100c as shown in Figure 2B.

[0030] When the processing circuitry is a dedicated processing circuit 100a, the dedicated processing circuit 100a may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof. The functions of the light source control device 10 may be realized by multiple separate processing circuits, or the functions of the light source control device 10 may be realized together by a single processing circuit.

[0031] When the processing circuitry is a processor 100b, the functions of the light source control device 10 are realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 100c. The processor 100b realizes the functions of the light source control device 10 by reading and executing the programs stored in the memory 100c. Here, examples of the memory 100c include non-volatile or volatile semiconductor memories such as random access memory (RAM), read-only memory (ROM), flash memory, erasable programmable read-only memory (EPROM), and electrically erasable programmable read-only memory (EEPROM), as well as magnetic disks, flexible disks, optical disks, compact disks, minidisks, and DVDs.

[0032] Note that some of the functions of the light source control device 10 may be realized by dedicated hardware, and other functions may be realized by software or firmware. In this way, the processing circuit can realize the functions of the light source control device 10 by hardware, software, firmware, or a combination of these.

[0033] <Operation> Next, the operation of the light source system 1 including the light source control device 10 will be described. The signal receiving unit 11 of the light source control device 10 receives a video signal from the camera 20 and supplies the received video signal to the signal synchronizer 12. The signal synchronizer 12 extracts a frame synchronization signal indicating the beginning of a frame from the video signal received from the signal receiving unit 11 and supplies the extracted frame synchronization signal to the offset adjustment unit 13. The offset adjustment unit 13 adds an offset time to the frame synchronization signal to generate an offset synchronization signal and supplies the generated offset synchronization signal to the light emission control unit 14. The light emission control unit 14 generates a light emission control signal based on the offset synchronization signal received from the offset adjustment unit 13. The light emission control unit 14 controls light emission by the light source 30 using the generated light emission control signal.

[0034] The exposure recognition unit 15 receives a video signal from the camera 20 and measures the exposure of the subject represented in the video signal. When measuring the exposure of the subject, the exposure recognition unit 15 determines whether to increase or decrease the offset time little by little within the range of the frame period. The offset adjustment unit 13 adds (increases or decreases) the offset time to the frame synchronization signal in accordance with the increase or decrease determination of the exposure recognition unit 15.

[0035] Second Embodiment Next, a light source control device 10A and a light source system 1A according to a second embodiment of the present disclosure will be described with reference to Figures 5 to 7. As shown in Figures 5 and 6, the light source system 1A differs from the light source system 1 according to the first embodiment in that it includes a plurality of light sources 30 (first light sources) and light sources 40 (second light sources). The number of light sources may be three or more.

[0036] Corresponding to the light source system 1A including the light source 30 and the light source 40, the light source control device 10A includes two light emission control units: a light emission control unit 141 (first light emission control unit) and a light emission control unit 142 (second light emission control unit).

[0037] The offset adjustment unit 13A included in the light source control device 10A is connected to these two light emission control units 141 and 142. The offset adjustment unit 13A corrects consecutive frame synchronization signals according to the number of light sources. For example, if the frame synchronization signal is 60 fps, the offset adjustment unit 13A multiplies the frame synchronization signal by 2 to obtain a modified frame synchronization signal of 30 fps. Based on the obtained modified frame synchronization signal, the offset adjustment unit 13A generates a modified frame synchronization signal for causing the light source 30 to emit light and a modified frame synchronization signal for causing the light source 40 to emit light. The modified frame synchronization signal for causing the light source 30 to emit light and the modified frame synchronization signal for causing the light source 40 to emit light are set to alternately turn on so that the light source 30 and the light source 40 emit light as shown in FIGS. 7B and 7C .

[0038] Also, as in the first embodiment, the offset adjustment unit 13A adds an offset time corresponding to each light source to each modified frame synchronization signal to generate an offset synchronization signal for the light source 30 and an offset synchronization signal for the light source 40. The offset time to be added differs depending on the light source 30 or the light source 40 depending on the installation positions of the light source 30 and the light source 40. Note that when the installation positions of the light source 30 and the light source 40 can be considered to be the same position, a common offset time may be added to both the light source 30 and the light source 40. The offset adjustment unit 13A supplies the generated offset synchronization signal to the corresponding light emission control unit 141 or 142. The other configurations are the same as in the first embodiment.

[0039] As described above, the light-source control device 10A according to the third embodiment includes an emission control unit 141 (first emission control unit) and an emission control unit 142 (second emission control unit). The light source system 1A also includes a light source 30 (first light source) and a light source 40 (second light source). The offset adjustment unit 13 generates a modified frame synchronization signal based on the extracted frame synchronization signal and the number of light sources (two in the above description), calculates a first offset time corresponding to the light source 30 (first light source), and adds the calculated first offset time to the modified frame synchronization signal to generate the first offset synchronization signal. The offset adjustment unit 13 also calculates a second offset time corresponding to the light source 40 (second light source), and adds the calculated second offset time to the modified frame synchronization signal to generate the second offset synchronization signal.

[0040] The light emission control unit 141 (first light emission control unit) generates a first light emission control signal that determines the light emission timing and light emission period based on the generated first offset synchronization signal, and controls the light emission of the light source 30 (first light source) in accordance with the generated first light emission control signal, and the light emission control unit 142 (second light emission control unit) generates a second light emission control signal that determines the light emission timing and light emission period based on the generated second offset synchronization signal, and controls the light emission of the light source 40 (second light source) in accordance with the generated second light emission control signal. In this way, the light emission control unit 141 (first light emission control unit) and the light emission control unit 142 (second light emission control unit) control the light emission of the light source 30 (first light source) or the light source 40 (second light source) so that only the light emission timing of the light source 30 (first light source) or the light emission timing of the light source 40 (second light source) is synchronized with the extracted frame synchronization signal.

[0041] By illuminating different lighting sources at a high frame rate, it is possible to obtain images with two independent lighting directions for the same situation. For example, as shown in Figures 7B and 7C, by illuminating different light sources for each of the multiple frames shown in Figure 7A, it is possible to obtain images with different lighting for each frame.

[0042] In machine vision applications, changing the direction of illumination can increase the amount of information needed to recognize an object. For example, the condition of fruit can be measured by illuminating it with light sources of different wavelengths, such as near-infrared wavelengths in addition to the visible range.

[0043] Third Embodiment Next, light source control devices 10C and 10D and a light source system 1B according to a third embodiment of the present disclosure will be described with reference to Fig. 8 and Fig. 9. As shown in Fig. 8, the light source system 1B includes a plurality of light source control devices 10C and 10D. Note that the number of light source control devices may be three or more.

[0044] The light source control device 10C (first light source control device) includes a signal receiving unit 11 (first signal receiving unit) that receives a video signal output by the camera 20, a signal synchronization unit 12A (first signal synchronization unit) that extracts a frame synchronization signal from the received video signal, an offset adjustment unit 13 (first offset adjustment unit) that generates a first offset synchronization signal by adding a first offset time to the extracted frame synchronization signal, and a light emission control unit 14 (first light emission control unit) that generates a first light emission control signal that determines a light emission timing and a light emission period based on the generated first offset synchronization signal and causes a light emitting element included in the light source 30 to emit light intermittently in accordance with the generated first light emission control signal. As in the first embodiment, the light source control device 10C may also include an exposure recognition unit 15.

[0045] The light source control device 10D (second light source control device) includes a signal receiving unit 11 (second signal receiving unit) that receives a video signal output by the camera 20, a signal synchronization unit 12B (second signal synchronization unit) that extracts a frame synchronization signal from the received video signal, an offset adjustment unit 13 (second offset adjustment unit) that adds a second offset time to the extracted frame synchronization signal to generate a second offset synchronization signal, and a light emission control unit 14 (second light emission control unit) that generates a second light emission control signal that determines a light emission timing and a light emission period based on the generated second offset synchronization signal and causes a light emitting element included in the light source 40 to emit light intermittently in accordance with the generated second light emission control signal. As in the first embodiment, the light source control device 10D may also include an exposure recognition unit 15.

[0046] The signal synchronization unit 12A (first signal synchronization unit) and the signal synchronization unit 12B (second signal synchronization unit) synchronize with each other, and within one exposure time, the light source 30 (first light source) emits light at a time that is offset from the light source 40 (second light source) emits light.

[0047] As shown in Figure 8, when two light source control devices 10C and 10D are provided for one camera 20, by connecting the signal synchronization unit 12A of the light source control device 10C with the signal synchronization unit 12B of the light source control device 10D, it is possible to divide the time during which the two light sources 30 and 40 emit light within the exposure time of one frame.

[0048] According to the configuration of the third embodiment, by differentiating the wavelength of light source 30 from the wavelength of light source 40, it is possible to detect the movement direction of a subject within one frame. For example, in the case of a method of emitting light as shown in FIG. 9, light source 40 emits light at the timing shown in FIG. 9C relative to the exposure time of camera 20 shown in FIG. 9A, and then light source 30 emits light within the same exposure time. This light emission makes it possible to detect that the subject has moved in a direction in which only the color of light source 30 is captured. Furthermore, the speed of movement can be detected from the number of pixels in which only the light of light source 30 is captured. Light source system 1B according to the third embodiment is useful when there are restrictions on the shooting frame rate.

[0049] Modification. Next, a modification of embodiment 1 or embodiment 2 will be described with reference to FIGS. 10A and 10B. FIG. 10A is a timing chart showing the exposure time of camera 20. FIG. 10B is a timing chart showing the operation of a light source provided in a light source system according to a modification. In embodiment 1 or embodiment 2, offset adjustment and light emission control are performed so that the exposure time and the light emission time overlap, but as shown in FIGS. 10A and 10B, offset adjustment and light emission control may be performed so that the exposure time and the light emission time do not overlap. In other words, offset adjustment and light emission control may be performed so that the light emission occurs at a timing different from the exposure time.

[0050] By controlling light emission as shown in FIG. 10 , it is possible to provide illumination that is not recorded by the camera 20 synchronized with the light source control device 10 or 10A, while presenting lighting effects or information to cameras other than the camera 20, humans, animals, etc. For example, when a person such as an announcer or reporter is reading text such as a news script, or when instructing such a person not to be captured by the camera 20, it is conceivable to control the light emission of the projector according to this modified example. In this specific example, it is possible to present an image that is not captured by the camera 20 but is visible to the announcer. Even when flashing light is used to intimidate or warn animals, etc., by using this method in synchronization with the monitoring camera, the light can be flashed to intimidate animals or insects without affecting the monitoring image.

[0051] It is possible to combine the embodiments, and to modify or omit each embodiment as appropriate.

[0052] The light source control technology of the present disclosure can be used as a technology for controlling an auxiliary light source when photographing a subject using a camera.

[0053] 1 Light source system, 1A Light source system, 1B Light source system, 10 Light source control device, 10A Light source control device, 10C Light source control device, 10D Light source control device, 11 Signal receiving unit, 12 Signal synchronization unit, 12A Signal synchronization unit, 12B Signal synchronization unit, 13 Offset adjustment unit, 13A Offset adjustment unit, 14 Light emission control unit, 15 Exposure recognition unit, 20 Camera (imaging device), 30 Light source, 40 Light source, 100a Processing circuit, 100b Processor, 100c Memory, 141 Light emission control unit, 142 Light emission control unit.

Claims

1. A light source control device comprising: a signal receiving unit that receives a video signal output by an imaging device; a signal synchronization unit that extracts a frame synchronization signal from the received video signal; an offset adjustment unit that assigns an offset time to the extracted frame synchronization signal to generate an offset synchronization signal; and at least one light emission control unit that generates a light emission control signal for determining a light emission timing and a light emission period based on the generated offset synchronization signal, and intermittently emits a light emitting element included in at least one light source according to the generated light emission control signal.

2. The light source control device according to claim 1, further comprising an exposure recognition unit that measures an exposure of a subject represented in the received video signal, wherein the light emission control unit intermittently emits the light emitting element included in the at least one light source so that the measured exposure becomes larger.

3. The at least one light emission control unit includes a first light emission control unit and a second light emission control unit, the at least one light source includes a first light source and a second light source, the offset adjustment unit generates a corrected frame synchronization signal based on the extracted frame synchronization signal and the number of the at least one light source, calculates a first offset time corresponding to the first light source, assigns the calculated first offset time to the corrected frame synchronization signal to generate a first offset synchronization signal, calculates a second offset time corresponding to the second light source, assigns the calculated second offset time to the corrected frame synchronization signal to generate a second offset synchronization signal, the first light emission control unit generates a first light emission control signal for determining a light emission timing and a light emission period based on the generated first offset synchronization signal, and controls the light emission of the first light source according to the generated first light emission control signal, and the second light emission control unit generates a second light emission control signal for determining a light emission timing and a light emission period based on the generated second offset synchronization signal, and controls the light emission of the second light source according to the generated second light emission control signal. The light source control device according to claim 1 or 2.

4. The first light emission control unit and the second light emission control unit control the light emission of the first light source or the second light source so that only one of the light emission timing of the first light source or the light emission timing of the second light source synchronizes with the extracted frame synchronization signal. The light source control device according to claim 3.

5. The offset adjustment unit applies the offset time so that the light emitting element included in the at least one light source emits light at a timing that does not overlap with the exposure time of the imaging device. The light source control device according to any one of claims 1 to 4.

6. A first signal receiving unit that receives a video signal output by the imaging device, a first signal synchronization unit that extracts a frame synchronization signal from the received video signal, and a first offset adjustment unit that applies a first offset time to the extracted frame synchronization signal to generate a first offset synchronization signal, and a first light emission control unit that generates a first light emission control signal that determines the light emission timing and the light emission period based on the generated first offset synchronization signal, and intermittently emits the light emitting element included in the first light source according to the generated first light emission control signal; A first light source control device comprising: a second signal receiving unit that receives the video signal output by the imaging device; a second signal synchronization unit that extracts a frame synchronization signal from the received video signal; and a second offset adjustment unit that applies a second offset time to the extracted frame synchronization signal to generate a second offset synchronization signal, and a second light emission control unit that generates a second light emission control signal that determines the light emission timing and the light emission period based on the generated second offset synchronization signal, and intermittently emits the light emitting element included in the second light source according to the generated second light emission control signal; A light source system comprising: the first signal synchronization unit and the second signal synchronization unit are synchronized with each other, and within one exposure time, the time when the first light source emits light and the time when the second light source emits light are shifted to emit light.

7. The first light source control device and the second light source control device further include an exposure recognition unit that measures the exposure of the subject represented in the received video signal, the first light emission control unit intermittently emits light from the light emitting element included in the first light source so that the measured exposure becomes larger, the second light emission control unit intermittently emits light from the light emitting element included in the second light source so that the measured exposure becomes larger, The light source system according to claim 6.

Images