System and method for strobe light for camera exposure control

Abstract

An electronic device includes a light source, a communication device, a processor in data communication with the light source and the communication device, and a hardware storage device in data communication with the processor. The electronic device includes a hardware storage device having instructions stored thereon that, when executed by a processor, cause the electronic device to receive a timing signal from a camera, where the timing signal includes an exposure timing of a camera exposure; providing exposure light pulses from the light source concurrently with the camera exposure; and after providing the exposure light pulse, providing a dummy light pulse that does not overlap the camera exposure.

Description

Background Art

[0001] Recording video for 3D reconstruction often requires high output studio lights at brightness that is very uncomfortable for the human subjects being recorded. Studio lighting intensity can be adjusted, but studio lighting constantly illuminates the scene to the brightness required for recording, even if the camera is only exposed for a small fraction of that time. Summary of the invention

[0002] In some embodiments, an electronic device includes: a light source, a communication device, a processor that performs data communication with the light source and the communication device, and a hardware storage device that performs data communication with the processor. The hardware storage device has instructions stored thereon, and when the instructions are executed by the processor, the electronic device: receives a timing signal from a camera, wherein the timing signal includes an exposure timing of camera exposure; provides an exposure light pulse from the light source simultaneously with the camera exposure; and after providing the exposure light pulse, provides a dummy light pulse that does not overlap with the camera exposure.

[0003] In some embodiments, a system includes: a light source, a camera, and a unit for coordinating the camera and the light source. The unit for coordinating the light source and the camera is configured to: coordinate a first exposure of the camera with a first exposure light pulse of the light source, a second camera exposure of the camera with a second exposure light pulse of the light source, and at least one dummy light pulse of the light source between the first exposure and the second exposure.

[0004] In some embodiments, a method of providing light to an object comprises: receiving a timing signal from a camera, wherein the timing signal comprises an exposure timing of a camera exposure; providing an exposure light pulse simultaneously with at least a portion of the camera exposure; and providing a dummy light pulse after the exposure light pulse, wherein the dummy light pulse is not simultaneous with any camera exposure and has a dead time between the exposure light pulse and the dummy light pulse.

[0005] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter.

[0006] Additional features and advantages will be set forth in the description below, and in part will be apparent from the description, or may be learned through practice of the teachings herein. The features and advantages of the present disclosure may be realized and obtained by means of the apparatus and combinations particularly pointed out in the appended claims. The features of the present disclosure will become more apparent from the following description and the appended claims, or may be learned through practice of the present disclosure as set forth below. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to describe the manner in which the above and other features of the present disclosure can be obtained, a more specific description will be presented with reference to specific embodiments thereof illustrated in the accompanying drawings. For better understanding, similar elements have been represented by similar reference numerals throughout the various drawings. Although some of the drawings may be schematic or enlarged representations of concepts, at least some of the drawings may be drawn to scale. Understanding that the drawings depict some example embodiments, the embodiments will be described and explained with additional specificity and detail through the use of the drawings, in which:

[0008] Figure 1 is a schematic top view of a system for imaging an object according to at least some embodiments of the present disclosure;

[0009] Figure 2 is a schematic top view of another system for imaging an object in accordance with at least some embodiments of the present disclosure;

[0010] Figure 3 are embodiments of exposure timing and light pulse timing according to at least some embodiments of the present disclosure;

[0011] Figure 4 is a flow chart illustrating a method of controlling a light source according to at least some embodiments of the present disclosure;

[0012] Figure 5 is a schematic representation of a light source according to at least some embodiments of the present disclosure; and

[0013] Figure 6 is a schematic representation of a camera in accordance with at least some embodiments of the present disclosure. DETAILED DESCRIPTION

[0014] The present disclosure generally relates to systems and methods for controlling light sources. More specifically, the present disclosure relates to coordinating a light source with a camera exposure to provide light during camera exposure. High resolution imaging and three-dimensional imaging of an object may require a high level of illumination of the object. Such high illumination may cause discomfort to the object (a human object in this example).

[0015] In some embodiments, a camera for imaging an object has a camera exposure during a frame time. For example, a camera that captures images at 30 frames per second (FPS) has a frame time of approximately 33 milliseconds (ms). The camera exposure duration for each frame is less than the frame time to allow the camera to: collect light signals using a photoreceptor array during the camera exposure duration, process the light signals, read out frame information to a memory, and reset the photoreceptor array in preparation for a second frame time. Thus, the camera collects light signals only during the camera exposure duration, and excess illumination of the object during the remainder of the frame time (which may be greater than 90% of the frame time) has little effect on the light signals captured by the camera. However, excess illumination of the object may have a negative impact on the object.

[0016] The subject may experience discomfort or disorientation from the high level of illumination during a video recording session. In some embodiments, the light source is configured to provide high brightness illumination to the subject during at least a portion of the camera exposure duration, and to provide less illumination in the remaining frame times between camera exposures. However, illuminating the subject only during camera exposures may result in flickering of the light source that is noticeable to the subject. For example, a light source that emits light during the camera exposure duration in each frame time (e.g., a 2 ms light pulse every 33 ms) for a 30 FPS camera produces a visible stroboscopic effect that may also cause discomfort or disorientation to the subject during a video recording session.

[0017] In some embodiments, the systems and methods according to the present disclosure provide a sufficiently high brightness exposure light pulse during at least a portion of the camera exposure, and provide at least one dummy pulse during the frame time before the next camera exposure and exposure light pulse in time. By pulsing the light source, the total luminous flux from the light source during the frame time is reduced while the camera receives a high brightness light signal. In some embodiments, the introduction of dummy pulses into the light source pulse sequence increases the frequency of the light pulses (and reduces the duration of the dead time between the light pulses) so that the object perceives a continuous light source of lower brightness. The object perceives the rapid light pulses as a continuous light source. The reduction in the total luminous flux from the pulses contributes to the perception of the continuous source. Reducing the total luminous flux from the light source also reduces the power consumption of the light source, thereby reducing the environmental impact. In the case of a video or photography session at a remote location or other location with limited power availability, the reduction in the total luminous flux from the light source also reduces the power consumption from the battery or other power storage device, thereby allowing a smaller battery or a longer session.

[0018] Figure 11 is a top view schematic diagram of an embodiment of a system 100 for imaging an object 102. In some embodiments, the system 100 includes a camera 104 and a light source 106 that communicates data with the camera 104. For example, the light source 106 may include one or more light emitting diodes (LEDs). The LED can provide a nanosecond response time to allow short light pulses with relatively high timing accuracy. In some embodiments, the camera 104 includes an electronic shutter. The electronic shutter can be a rolling shutter or a global shutter. The rolling shutter will read the camera sensor from top to bottom. The pixels on the top of the camera sensor will first be turned on for exposure, and the active pixels of the camera sensor will "roll" downward to the bottom. In some embodiments, the camera 104 includes a global shutter. The global shutter operates by exposing the entire scene from top to bottom at once. Instead of turning on the pixels from the top of the sensor and working downward like a scan, the sensor uses all pixels together to capture the scene at once.

[0019] In some embodiments, the camera 104 sends a timing signal 108 to the light source 106 to illuminate the object 102. The light source 106 emits a plurality of light pulses based at least in part on the timing signal received from the camera 104. In some embodiments, the timing signal 108 includes an exposure timing that indicates to the light source 106 when a camera exposure begins. In some embodiments, the timing signal 108 includes an exposure duration that indicates to the light source 106 how long a shutter of the camera remains open during the camera exposure. In some embodiments, a processor of the light source 106 receives the timing signal from the camera 104 and calculates a light pulse timing based at least in part on the timing signal, the light pulse timing including an amount of light pulses and a light pulse duration during a frame time.

[0020] The light source 106 illuminates the object 102 during at least a portion of the camera exposure to provide a light signal to the camera 104. In some embodiments, the timing signal 108 also includes a frame timing indicating a frame rate or frame time of the camera 104. In some embodiments, the light source 106 also provides at least one dummy light pulse in the frame time after the exposure light pulse and before the next camera exposure. Figure 1 The depicted embodiment includes a timing signal 108 sent directly from the camera 104 to the light source 106, but in other embodiments, the timing controller receives the timing signal from the camera and sends one or more light signals to the light source to control the timing of the light pulses based at least in part on the timing signal.

[0021] Figure 22 is a top view of another embodiment of a system 200 having a timing controller 210 for data communication between a camera 204 and a light source 206. For example, the timing controller 210 receives a timing signal 208 from the camera 204 and calculates a light pulse timing based at least in part on the timing signal, the light pulse timing including the amount of light pulses and the duration of light pulses during a frame time. The timing controller 210 then sends a light pulse instruction 212 to the light source 206 to illuminate the object 202 according to the light pulse timing.

[0022] Figure 3 316. is a timing diagram that overlaps exposure timing 314 with light pulse timing 316. In some embodiments, exposure timing 314 includes a camera exposure start time 318 of a camera exposure 319. The camera exposure start time 318 indicates when the global shutter of the camera opens (e.g., when the photoreceptor array of the camera sensor becomes active) or when the rolling shutter of the camera opens (e.g., when the first pixel of the photoreceptor array of the camera sensor becomes active). The camera exposure 319 has a camera exposure duration 320, and the exposure timing 314 has a frame time 322, which is the period between camera exposures 319. In some embodiments, the camera exposure duration 320 reflects the amount of time that the camera sensor is active and collecting light signals. The remainder of the frame time 322 includes signal readout to memory, sensor reset, and other processes to prepare the camera sensor before the next frame that follows.

[0023] In some embodiments, exposure light pulse 324 at least partially overlaps camera exposure 319. In some examples, exposure light pulse 324 has exposure light pulse start 326 that is the same as camera exposure start 318. In some examples, exposure light pulse 324 has exposure light pulse start 326 that is before camera exposure start 318. For example, exposure light pulse 324 has exposure light pulse start 326 that is after camera exposure start 318.

[0024] In some examples, the exposure light pulse 324 has an exposure light pulse duration 328 that is the same as the camera exposure duration 320. In some examples, the exposure light pulse 324 has an exposure light pulse duration 328 that is greater than the camera exposure duration 320. In some examples, the exposure light pulse 324 has an exposure light pulse duration 328 that is less than the camera exposure duration 320. In at least one example, the exposure light pulse 324 has an exposure light pulse start 326 that is the same as the camera exposure start 318 and an exposure light pulse duration 328 that is the same as the camera exposure duration 320, such that the exposure light pulse 324 starts and ends at the same time as the camera exposure 319. In at least one example, the exposure light pulse 324 has an exposure light pulse start 326 that is the same as the camera exposure start 318 and the exposure light pulse 324 has an exposure light pulse duration 328 that is greater than the camera exposure duration 320 to ensure that the camera exposure is fully illuminated.

[0025] As described herein, a light source that provides light only during camera exposure will ensure that the camera exposure is fully illuminated, but the light source will also produce a visible strobing or flickering effect on the subject. In some embodiments, the light pulse timing 316 includes at least one dummy light pulse 330-1, 330-2 provided by the light source prior to the next camera exposure and / or exposure light pulse. In some embodiments, the light pulse timing 316 includes a single dummy light pulse 330-1. In some embodiments, the light pulse timing 316 includes multiple dummy pulses 330-1, 330-2.

[0026] By experimentation, when the light pulse timing provides light pulses at least 20% of the time with a dead time 336 between light pulses (e.g., exposure light pulse 324 and dummy light pulses 330-1, 330-2) less than 15 ms, human subjects perceive the pulsed light source as a continuous light source. For example, three light pulses of 2.2 ms in a 33 ms frame time 322 (exposure light pulse duration 328 and dummy light pulse duration 334) each provide a 20% duty cycle (6.6 ms / 33 ms=0.20) within the frame time 322.

[0027] In some embodiments, the dead time 336 between each light pulse is equal, so that the time periods between light pulses and / or light pulse starts (e.g., exposure light pulse start 326 and dummy light pulse start 332) are positioned at equal intervals within the frame time 322 to further create the perception of a continuous light source. For example, in the described embodiment, the dead time 336 between pulses is 8.8 ms ((2.2 ms + 8.8 ms) * 3 = 33 ms). In some embodiments, the first dead time 336 between two light pulses and the second dead time between other light pulses are different. For example, in some embodiments, the exposure light pulse duration 328 can be greater than the dummy light pulse duration 334, and the dead time 336 therebetween can be greater than the dead time between the dummy light pulse and another light pulse.

[0028] The described embodiments include constant dummy light pulse durations. In some embodiments, the dummy light pulse duration 334 of the first dummy light pulse 330-1 is greater than the dummy light pulse duration of the second dummy light pulse 330-2. In some embodiments, the dummy light pulse duration 334 of the first dummy light pulse 330-1 is less than the dummy light pulse duration of the second dummy light pulse 330-2.

[0029] In some embodiments, exposure light pulse intensity 338 is selected based at least in part on a brightness of a light signal expected at the camera sensor. In some embodiments, dummy light pulse intensity 338 is substantially the same as exposure light pulse intensity 338. In some embodiments, dummy light pulse intensity 340 is greater than exposure light pulse intensity 338. In some embodiments, dummy light pulse intensity 340 is less than exposure light pulse intensity 338.

[0030] In some embodiments, the exposure light pulse intensity 338 and / or the dummy light pulse intensity 340 have a brightness value of at least 500 lux at the object. Below 500 lux, most human subjects experience little discomfort. In some embodiments, the exposure light pulse intensity 338 and / or the dummy light pulse intensity 340 have a brightness value of at least 750 lux at the object. In some embodiments, the exposure light pulse intensity 338 and / or the dummy light pulse intensity 340 have a brightness value of at least 1000 lux at the object. In some embodiments, the exposure light pulse intensity 338 and / or the dummy light pulse intensity 340 have a brightness value of at least 2000 lux at the object. Because the brightness of the light pulses is perceived as distributed over the frame time, a higher brightness than that comfortable for the user can be used.

[0031] Figure 4442. In some embodiments, the method 442 includes receiving a timing signal from a camera at 444, wherein the timing signal includes an exposure timing. In some embodiments, the timing signal includes a camera exposure duration and / or a camera exposure start time.

[0032] In some embodiments, a unit for coordinating a light source and a camera receives the timing signal and provides instructions to at least one component of the light source to provide an exposure light pulse at 446 at least partially simultaneously (e.g., overlapping in time) with the exposure timing of the camera exposure.

[0033] In some embodiments, the means for coordinating the light source and the camera includes a processor in the light source that receives a timing signal from the camera and sends an electrical signal to an LED or other light-emitting component of the light source to provide an exposure light pulse. In some embodiments, the means for coordinating the light source and the camera includes a processor in the camera that receives a timing signal from sensor firmware and sends instructions to at least one component of the light source to provide an exposure light pulse. In some embodiments, the means for coordinating the light source and the camera includes a timing controller that is in data communication with the light source and receives a timing signal from the camera.

[0034] The method 442 also includes providing instructions to at least one component of the light source to provide a dummy light pulse at least partially simultaneously (e.g., overlapping in time) with an exposure timing of the camera exposure at 448. In some embodiments, the means for coordinating the light source and the camera calculates a dummy pulse timing of the dummy light pulse based at least in part on the timing signal. For example, the timing signal includes a frame time. In some embodiments, the dummy pulse timing of the dummy light pulse is calculated based at least in part on the timing signal by dividing the frame time into equal intervals and setting the exposure light pulse start and the (one or more) dummy light pulse start at equal intervals.

[0035] In some embodiments, method 442 includes providing multiple light pulses (i.e., exposure light pulses and (one or more) dummy light pulses) based on ensuring that the sum of the light pulses is equal to at least 20% of the frame time and the dead time between the light pulses is no greater than 15 ms. In some embodiments, method 442 includes providing multiple light pulses (i.e., exposure light pulses and (one or more) dummy light pulses) based on ensuring that the sum of the light pulses is equal to at least 25% of the frame time and the dead time between the light pulses is no greater than 10 ms.

[0036] Figure 55 is a system diagram of a light source 506 including a processor 550 in data communication with a communication device 552 to receive a timing signal from a camera. The processor 550 is also in electrical communication with a light emitting assembly 554 (such as an LED array) to control light pulses from the light source 506. In some embodiments, the light emitting assembly 554 includes or is controlled in part by a pulse width modulator (PWM). In some embodiments, the pulse intensity is adjusted by at least 20 kilohertz (kHz) PWM. In some embodiments, the pulse intensity is adjusted by at least 50kHz PWM. In some embodiments, the pulse intensity is adjusted by at least 100kHz PWM.

[0037] In some embodiments, the processor 550 of the light source 506 is in data communication with a hardware storage device 556. The hardware storage device 556 may have instructions stored thereon that, when executed by the processor, cause the light source to perform any of the methods described herein.

[0038] In some embodiments, hardware storage device 556 is any non-transitory computer-readable medium on which instructions can be stored. Hardware storage device 556 can be any type of solid-state memory; volatile memory, such as static random access memory (SRAM) or dynamic random access memory (DRAM); or non-volatile memory, such as read-only memory (ROM), including programmable ROM (PROM), erasable PROM (EPROM) or EEPROM; magnetic storage media, such as magnetic tape; plane-based storage devices, such as hard drives; optical media, such as compact disks (CDs), digital video disks (DVDs), Blu-ray disks, or other optical media; removable media, such as USB drives; non-removable media, such as internal SATA or non-volatile memory express (NVMe) style NAND flash memory; or any other non-transitory storage media.

[0039] In some embodiments, the communication device 552 is a wireless communication device. For example, the wireless communication device can provide radio frequency wireless communication, such as a Wi-Fi communication device, a Bluetooth communication device, or a near field communication NFC communication device. In other examples, the wireless communication device can provide optical wireless communication, such as an infrared wireless communication device.

[0040] In some embodiments, the communication device 552 is a wired communication device. For example, the wired communication device can provide electrical signal communication, such as a coaxial wired communication device or an Ethernet wired communication device. In another example, the wired communication device can provide optical wired signal communication, such as an optical fiber wired communication device. In some embodiments, compared with wireless communication devices, wired communication devices can provide faster communication times with less risk of losing data packets or interference.

[0041] Figure 6 6 is a system diagram of a camera 604 including a processor 650 in data communication with a communication device 652 to transmit timing signals from the camera 604 to the light source. In some embodiments, the processor 650 is also in electrical communication with a camera sensor 658 (such as a photoreceptor array) to capture light signals that image an object. In some embodiments, the processor 650 of the camera 604 is in data communication with a hardware storage device 656. The hardware storage device 656 may have instructions stored thereon that, when executed by the processor, cause the light source to perform any of the methods described herein.

[0042] In some embodiments, hardware storage device 656 is any non-transitory computer-readable medium on which instructions can be stored. Hardware storage device 656 can be any type of solid-state memory; volatile memory, such as static random access memory (SRAM) or dynamic random access memory (DRAM); or non-volatile memory, such as read-only memory (ROM), including programmable ROM (PROM), erasable PROM (EPROM) or EEPROM; magnetic storage media, such as magnetic tape; plane-based storage devices, such as hard drives; optical media, such as compact disks (CDs), digital video disks (DVDs), Blu-ray disks, or other optical media; removable media, such as USB drives; non-removable media, such as internal SATA or non-volatile memory express (NVMe) style NAND flash memory; or any other non-transitory storage media.

[0043] In some embodiments, the communication device 652 is a wireless communication device. For example, the wireless communication device can provide radio frequency wireless communication, such as a Wi-Fi communication device, a Bluetooth communication device, or a near field communication NFC communication device. In other examples, the wireless communication device can provide optical wireless communication, such as an infrared wireless communication device.

[0044] In some embodiments, the communication device 652 is a wired communication device. For example, the wired communication device can provide electrical signal communication, such as a coaxial wired communication device or an Ethernet wired communication device. In another example, the wired communication device can provide optical wired signal communication, such as an optical fiber wired communication device. In some embodiments, compared with wireless communication devices, wired communication devices can provide faster communication times with less risk of losing data packets or interference.

[0045] Industrial Applicability

[0046] The present disclosure generally relates to systems and methods for controlling light sources. More specifically, the present disclosure relates to coordinating a light source with camera exposure to provide light during camera exposure. High resolution imaging and three-dimensional imaging of an object may require high levels of illumination of the object. Such high illumination may cause discomfort to the object (a human subject in this example).

[0047] In some embodiments, a camera for imaging an object has a camera exposure during a frame time. For example, a camera that captures images at 30 frames per second (FPS) has a frame time of approximately 33 milliseconds (ms). The camera exposure duration for each frame is less than the frame time to allow the camera to: collect light signals using a photoreceptor array during the camera exposure duration, process the light signals, read out frame information to a memory, and reset the photoreceptor array in preparation for a second frame time. Thus, the camera collects light signals only during the camera exposure duration, and excess illumination of the object during the remainder of the frame time (which can be greater than 90% of the frame time) has little effect on the light signals captured by the camera. However, excess illumination of the object may have a negative impact on the object.

[0048] The subject may experience discomfort or disorientation from the high level of illumination during a video recording session. In some embodiments, the light source is configured to provide high brightness illumination to the subject during at least a portion of the camera exposure duration, and to provide less illumination in the remaining frame times between camera exposures. However, illuminating the subject only during camera exposures may result in flickering of the light source that is noticeable to the subject. For example, a light source that emits light for every frame time of a 30 FPS camera (e.g., a 2 ms light pulse every 33 ms) during the camera exposure duration may produce a visible stroboscopic effect that may also cause discomfort or disorientation to the subject during a video recording session.

[0049] In some embodiments, the systems and methods according to the present disclosure provide exposure light pulses of sufficiently high brightness during at least a portion of a camera exposure, and provide at least one dummy pulse during a frame time before the next camera exposure and exposure light pulse in time. By pulsing the light source, the total luminous flux from the light source during the frame time is reduced while the camera receives a high-brightness light signal. In some embodiments, the introduction of dummy pulses into the light source pulse sequence increases the frequency of the light pulses (and reduces the duration of the dead time between the light pulses), so that the object perceives a continuous light source of lower brightness. The object perceives the rapid light pulses as a continuous light source. The reduction in the total luminous flux from the pulses contributes to the perception of the continuous source. Reducing the total luminous flux from the light source also reduces the power consumption of the light source, thereby reducing the environmental impact. In the case of a video or photography session at a remote location or other location with limited power availability, the reduction in the total luminous flux from the light source also reduces the power consumption from the battery or other power storage device, thereby allowing a smaller battery or a longer session.

[0050] In some embodiments, a system for imaging an object includes a camera and a light source that communicates data with the camera. For example, the light source may include one or more light emitting diodes (LEDs). The LED can provide a nanosecond response time to allow short light pulses with relatively high timing accuracy. In some embodiments, the camera includes an electronic shutter. The electronic shutter may be a rolling shutter or a global shutter. The rolling shutter will read the camera sensor from top to bottom. The pixels on the top of the camera sensor will be turned on first for exposure, and the active pixels of the camera sensor "roll" down to the bottom. In some embodiments, the camera includes a global shutter. The global shutter operates by exposing the entire scene from top to bottom at once. Instead of turning on the pixels from the top of the sensor and working downward like a scan, the sensor uses all pixels together to capture the scene at once.

[0051] In some embodiments, the camera sends a timing signal to the light source to illuminate the object. The light source emits a plurality of light pulses based at least in part on the timing signal received from the camera. In some embodiments, the timing signal includes an exposure timing that indicates to the light source when camera exposure begins. In some embodiments, the timing signal includes an exposure duration that indicates to the light source how long a shutter of the camera remains open during camera exposure. In some embodiments, a processor of the light source receives the timing signal from the camera and calculates light pulse timing based at least in part on the timing signal, the light pulse timing including an amount of light pulses during a frame time and a light pulse duration.

[0052] The light source illuminates the object during at least a portion of the camera exposure to provide a light signal to the camera. In some embodiments, the timing signal also includes a frame timing indicating a frame rate or frame time of the camera. In some embodiments, the light source also provides at least one dummy light pulse in the frame time after the exposure light pulse and before the next camera exposure. Although some embodiments described herein include timing signals sent directly from the camera to the light source, in other embodiments, the timing controller receives the timing signal from the camera and transmits one or more light signals to the light source to control the timing of the light pulses based at least in part on the timing signal.

[0053] In some embodiments, the system has a timing controller that communicates data between the camera and the light source. For example, the timing controller receives a timing signal from the camera and calculates a light pulse timing based at least in part on the timing signal, the light pulse timing including the amount of light pulses and the light pulse duration during a frame time. The timing controller then sends a light pulse instruction to the light source to illuminate the object according to the light pulse timing.

[0054] In some embodiments, the exposure timing includes a camera exposure start time of the camera exposure. The camera exposure start time indicates when the global shutter of the camera opens (e.g., when the photoreceptor array of the camera sensor becomes active) or when the rolling shutter of the camera opens (e.g., when the first pixel of the photoreceptor array of the camera sensor becomes active). The camera exposure has a camera exposure duration, and the exposure timing has a frame time that is the period between camera exposures. In some embodiments, the camera exposure duration reflects the amount of time that the camera sensor is active and collects light signals. The remainder of the frame time includes signal readout to memory, sensor reset, and other processes to prepare the camera sensor before the next frame.

[0055] In some embodiments, the exposure light pulse at least partially overlaps with the camera exposure. In some examples, the exposure light pulse has an exposure light pulse start that is the same as the camera exposure start. In some examples, the exposure light pulse has an exposure light pulse start that is before the camera exposure start. For example, the exposure light pulse has an exposure light pulse start that is after the camera exposure start.

[0056] In some examples, the exposure light pulse has an exposure light pulse duration that is the same as the camera exposure duration. In some examples, the exposure light pulse has an exposure light pulse duration that is greater than the camera exposure duration. In some examples, the exposure light pulse has an exposure light pulse duration that is less than the camera exposure duration. In at least one example, the exposure light pulse has an exposure light pulse start that is the same as the camera exposure start and an exposure light pulse duration that is the same as the camera exposure duration, such that the exposure light pulse starts and ends at the same time as the camera exposure. In at least one example, the exposure light pulse has an exposure light pulse start that is the same as the camera exposure start and the exposure light pulse has an exposure light pulse duration that is greater than the camera exposure duration to ensure that the camera exposure is fully illuminated.

[0057] As described herein, a light source that provides light only during camera exposure will ensure that the camera exposure is fully illuminated, but the light source will also produce a visible strobing or flickering effect on the subject. In some embodiments, the light pulse timing includes at least one dummy light pulse provided by the light source prior to the next camera exposure and / or exposure light pulse. In some embodiments, the light pulse timing includes a single dummy light pulse. In some embodiments, the light pulse timing includes multiple dummy pulses.

[0058] By experimentation, when the light pulse timing provides light pulses at least 20% of the time when the dead time between light pulses (e.g., exposure light pulses and dummy light pulses) is less than 15 ms, human subjects perceive the pulsed light source as a continuous light source. For example, three light pulses of 2.2 ms in a 33 ms frame time (exposure light pulse duration and dummy light pulse duration) each provide a 20% duty cycle in the frame time (6.6 ms / 33 ms=0.20).

[0059] In some embodiments, the dead time between each light pulse is equal, so that the time periods between light pulses and / or light pulse starts (e.g., the exposure light pulse start and the dummy light pulse start) are positioned at equal intervals within the frame time to further create the perception of a continuous light source. For example, in the described embodiment, the dead time between pulses is 8.8ms ((2.2ms+8.8ms)*3=33ms). In some embodiments, the first dead time between two light pulses and the second dead time between other light pulses are different. For example, in some embodiments, the exposure light pulse duration can be greater than the dummy light pulse duration, and the dead time between them can be greater than the dead time between the dummy light pulse and another light pulse.

[0060] The described embodiments include a constant dummy light pulse duration. In some embodiments, the dummy light pulse duration of the first dummy light pulse is greater than the dummy light pulse duration of the second dummy light pulse. In some embodiments, the dummy light pulse duration of the first dummy light pulse is less than the dummy light pulse duration of the second dummy light pulse.

[0061] In some embodiments, the exposure light pulse intensity is selected based at least in part on the brightness of the light signal expected at the camera sensor. In some embodiments, the dummy light pulse intensity is substantially the same as the exposure light pulse intensity. In some embodiments, the dummy light pulse intensity is greater than the exposure light pulse intensity. In some embodiments, the dummy light pulse intensity is less than the exposure light pulse intensity.

[0062] In some embodiments, the exposure light pulse and / or the dummy light pulse has a brightness value of at least 500 lux at the object. Below 500 lux, most human subjects experience little discomfort. In some embodiments, the exposure light pulse and / or the dummy light pulse has a brightness value of at least 750 lux at the object. In some embodiments, the exposure light pulse and / or the dummy light pulse has a brightness value of at least 1000 lux at the object. In some embodiments, the exposure light pulse and / or the dummy light pulse has a brightness value of at least 2000 lux at the object. Because the brightness of the light pulses is perceived as distributed over the frame time, a higher brightness than that comfortable for the user can be used.

[0063] In some embodiments, a method of controlling a light source includes receiving a timing signal from a camera, wherein the timing signal includes an exposure timing. In some embodiments, the timing signal includes a camera exposure duration and / or a camera exposure start time.

[0064] In some embodiments, a unit for coordinating a light source and a camera receives the timing signal and provides instructions to at least one component of the light source to provide an exposure light pulse at least partially simultaneously (eg, overlapping in time) with an exposure timing of the camera exposure.

[0065] In some embodiments, the means for coordinating the light source and the camera includes a processor in the light source that receives a timing signal from the camera and sends an electrical signal to an LED or other light-emitting component of the light source to provide an exposure light pulse. In some embodiments, the means for coordinating the light source and the camera includes a processor in the camera that receives a timing signal from sensor firmware and sends instructions to at least one component of the light source to provide an exposure light pulse. In some embodiments, the means for coordinating the light source and the camera includes a timing controller that is in data communication with the light source and receives a timing signal from the camera.

[0066] The method also includes providing instructions to at least one component of the light source to provide a dummy light pulse at least partially simultaneously (e.g., overlapping in time) with an exposure timing of the camera exposure. In some embodiments, the means for coordinating the light source and the camera calculates a dummy pulse timing of the dummy light pulse based at least in part on the timing signal. For example, the timing signal includes a frame time. In some embodiments, the dummy pulse timing of the dummy light pulse is calculated based at least in part on the timing signal by dividing the frame time into equal intervals and setting the exposure light pulse start and the (one or more) dummy light pulse start at equal intervals.

[0067] In some embodiments, the method includes providing a plurality of light pulses (i.e., exposure light pulses and (one or more) dummy light pulses) based on ensuring that the sum of the light pulses is equal to at least 20% of the frame time and that the dead time between the light pulses is no greater than 15 ms. In some embodiments, the method includes providing a plurality of light pulses (i.e., exposure light pulses and (one or more) dummy light pulses) based on ensuring that the sum of the light pulses is equal to at least 25% of the frame time and that the dead time between the light pulses is no greater than 10 ms.

[0068] In some embodiments, the light source includes a processor that performs data communication with a communication device to receive a timing signal from a camera. The processor further communicates electrically with a light emitting assembly (such as an LED array) to control light pulses from the light source. In some embodiments, the light emitting assembly includes or is controlled in part by a pulse width modulator (PWM). In some embodiments, the pulse intensity is adjusted by at least 20 kilohertz (kHz) PWM. In some embodiments, the pulse intensity is adjusted by at least 50kHz PWM. In some embodiments, the pulse intensity is adjusted by at least 100kHz PWM.

[0069] In some embodiments, the processor of the light source is in data communication with a hardware storage device. The hardware storage device may have instructions stored thereon, which, when executed by the processor, cause the light source to perform any of the methods described herein.

[0070] In some embodiments, a hardware storage device is any non-transitory computer-readable medium on which instructions can be stored. The hardware storage device can be any type of solid-state memory; volatile memory, such as static random access memory (SRAM) or dynamic random access memory (DRAM); or non-volatile memory, such as read-only memory (ROM), including programmable ROM (PROM), erasable PROM (EPROM) or EEPROM; magnetic storage media, such as magnetic tape; plane-based storage devices, such as hard drives; optical media, such as compact disks (CDs), digital video disks (DVDs), Blu-ray disks, or other optical media; removable media, such as USB drives; non-removable media, such as internal SATA or non-volatile memory express (NVMe) style NAND flash memory; or any other non-transitory storage medium.

[0071] In some embodiments, the communication device is a wireless communication device. For example, the wireless communication device can provide radio frequency wireless communication, such as a Wi-Fi communication device, a Bluetooth communication device, or a near field communication NFC communication device. In other examples, the wireless communication device can provide optical wireless communication, such as an infrared wireless communication device.

[0072] In some embodiments, the communication device is a wired communication device. For example, the wired communication device can provide electrical signal communication, such as a coaxial wired communication device or an Ethernet wired communication device. In another example, the wired communication device can provide optical wired signal communication, such as an optical fiber wired communication device. In some embodiments, compared with wireless communication devices, wired communication devices can provide faster communication times with less risk of losing data packets or interference.

[0073] In some embodiments, the camera includes a processor that is in data communication with a communication device to transmit a timing signal from the camera toward the light source. In some embodiments, the processor is further in electrical communication with a camera sensor (such as a photoreceptor array) to capture light signals that image an object. In some embodiments, the processor of the camera is in data communication with a hardware storage device. The hardware storage device may have instructions stored thereon that, when executed by the processor, cause the light source to perform any of the methods described herein.

[0074] In some embodiments, a hardware storage device is any non-transitory computer-readable medium on which instructions can be stored. The hardware storage device can be any type of solid-state memory; volatile memory, such as static random access memory (SRAM) or dynamic random access memory (DRAM); or non-volatile memory, such as read-only memory (ROM), including programmable ROM (PROM), erasable PROM (EPROM) or EEPROM; magnetic storage media, such as magnetic tape; plane-based storage devices, such as hard drives; optical media, such as compact disks (CDs), digital video disks (DVDs), Blu-ray disks, or other optical media; removable media, such as USB drives; non-removable media, such as internal SATA or non-volatile memory express (NVMe) style NAND flash memory; or any other non-transitory storage medium.

[0075] In some embodiments, the communication device is a wireless communication device. For example, the wireless communication device can provide radio frequency wireless communication, such as a Wi-Fi communication device, a Bluetooth communication device, or a near field communication NFC communication device. In other examples, the wireless communication device can provide optical wireless communication, such as an infrared wireless communication device.

[0076] In some embodiments, the communication device is a wired communication device. For example, the wired communication device can provide electrical signal communication, such as a coaxial wired communication device or an Ethernet wired communication device. In another example, the wired communication device can provide optical wired signal communication, such as an optical fiber wired communication device. In some embodiments, compared with wireless communication devices, wired communication devices can provide faster communication times with less risk of losing data packets or interference.

[0077] The present disclosure relates to systems and methods for controlling light sources according to at least the examples provided in the following sections:

[0078] [A1] In some embodiments, an electronic device includes: a light source, a communication device, a processor for data communication with the light source and the communication device, and a hardware storage device for data communication with the processor. The hardware storage device has instructions stored thereon, and when the instructions are executed by the processor, the electronic device: receives a timing signal from a camera, wherein the timing signal includes an exposure timing of camera exposure; provides an exposure light pulse from the light source simultaneously with the camera exposure; and after providing the exposure light pulse, provides a dummy light pulse that does not overlap with the camera exposure.

[0079] [A2] In some embodiments, the light source of [A1] includes at least one light emitting diode.

[0080] [A3] In some embodiments, the light source of [A1] or [A2] also includes a 20 kHz pulse width modulator configured to adjust pulse intensity.

[0081] [A4] In some embodiments, the communication device of any one of [A1] to [A3] is a wired communication device.

[0082] [A5] In some embodiments, the exposure light pulse of any one of [A1] to [A4] has a brightness of at least 500 lux.

[0083] [B1] In some embodiments, a system includes: a light source, a camera, and a unit for coordinating the camera and the light source. The unit for coordinating the light source and the camera is configured to coordinate a first exposure of the camera with a first exposure light pulse of the light source, a second camera exposure of the camera with a second exposure light pulse of the light source, and at least one dummy light pulse of the light source between the first exposure and the second exposure.

[0084] [B2] In some embodiments, the unit for coordinating of [B1] includes a controller in data communication with the camera and the light source.

[0085] [B3] In some embodiments, the means for coordinating of [B1] includes a processor in the light source, wherein the processor is configured to receive exposure timing from the camera.

[0086] [B4] In some embodiments, the unit for coordinating of [B1] includes a processor in the camera, wherein the processor is configured to transmit the exposure timing and the virtual timing to the light source.

[0087] [B5] In some embodiments, the camera of any one of [B1] to [B4] has a global shutter.

[0088] [C1] In some embodiments, a method for providing light to an object comprises: receiving a timing signal from a camera, wherein the timing signal comprises an exposure timing of a camera exposure; providing an exposure light pulse simultaneously with at least a portion of the camera exposure; and providing a dummy light pulse after the exposure light pulse, wherein the dummy light pulse is not synchronized with any camera exposure and has a specific dead time between the exposure light pulse and the dummy light pulse.

[0089] [C2] In some embodiments, the timing signal of [C1] includes an exposure duration and the exposure light pulse has an exposure light pulse duration that is longer than the exposure duration.

[0090] [C3] In some embodiments, the timing signal of [C1] or [C2] includes a frame time between exposures, and the dummy light pulses start at equal intervals within the frame time.

[0091] [C4] In some embodiments, the dummy light pulse of any one of [C1] to [C3] is a first dummy light pulse, and the method further includes providing a second dummy light pulse at a second equal interval after the first dummy light pulse.

[0092] [C5] In some embodiments, the total duty cycle of the light source of any one of [C1] to [C4] is at least 20% in the frame time.

[0093] [C6] In some embodiments, the timing signal of any one of [C1] to [C5] includes a frame time between exposures, and the method also includes providing a second exposure light pulse after the frame time.

[0094] [C7] In some embodiments, the exposure light pulse of any one of [C1] to [C6] has an exposure light intensity, and the dummy light pulse has a dummy light intensity, and the exposure light intensity and the dummy light intensity are equal.

[0095] [C8] In some embodiments, the dead time of any one of [C1] to [C7] does not exceed 15 ms.

[0096] [C9] In some embodiments, the exposure light pulse of any one of [C1] to [C8] has an exposure duration, and the dummy light pulse has a dummy light duration, and the exposure duration and the dummy light duration are equal.

[0097] [C10] In some embodiments, the dummy light pulse of [C9] is a first dummy light pulse, and the method further includes providing a second dummy light pulse after the first dummy light pulse, wherein the second dummy light pulse has a second dummy light duration, and the dummy light duration and the second dummy light duration are equal.

[0098] The articles "one", "an" and "said" are intended to mean one or more elements in the elements present in the preceding description. The terms "including", "comprising" and "having" are intended to be inclusive, and mean that there may be additional elements in addition to the listed elements. In addition, it should be understood that the reference to "one embodiment" or "embodiment" of the present disclosure is not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the features. For example, any element described in the embodiments herein can be combined with any element of any other embodiment described herein. The numbers, percentages, ratios or other values ​​described in this article are intended to include the value, as well as other values ​​of "about" or "approximately" the value, as will be understood by those of ordinary skill in the art. Therefore, the value should be broadly interpreted as covering a value that is at least close enough to the value to perform the desired function or achieve the desired result. The value includes at least the expected changes in a suitable manufacturing or production process, and may include values ​​within 5%, within 1%, within 0.1% or within 0.01% of the value.

[0099] In view of the present disclosure, those of ordinary skill in the art will recognize that equivalent constructions do not depart from the scope of the present disclosure, and that various changes, substitutions, and modifications may be made to the embodiments disclosed herein without departing from the scope of the present disclosure. Equivalent constructions including functional "unit plus function" clauses are intended to cover structures described herein as performing the functions, including structural equivalents that operate in the same manner and equivalent structures that provide the same functions. It is the express intention of the applicant that the applicant does not invoke unit plus function or other functional claims for any claim, except for those where the words "unit for..." appear with an associated function. Each addition, deletion, and modification of the embodiments that falls within the meaning and scope of the claims will be covered by the claims.

[0100] It should be understood that any directions or reference frames in the foregoing description are only relative directions or movements. For example, any reference to "front" and "back" or "top" and "bottom" or "left" and "right" only describes the relative positions or movements of the relevant elements.

[0101] The present disclosure may be embodied in other specific forms without departing from its characteristics. The described embodiments are considered to be illustrative rather than restrictive. Therefore, the scope of the present disclosure is indicated by the appended claims rather than by the foregoing description. Changes falling within the equivalent meaning and scope of the claims will be included within their scope.

Claims

1. An electronic device, comprising: light source; Communications equipment; a processor in data communication with the communication device and the light source; as well as a hardware storage device in data communication with the processor, the hardware storage device having instructions stored thereon, the instructions, when executed by the processor, causing the electronic device to: receiving a timing signal from a camera, wherein the timing signal includes an exposure timing of the camera exposure, providing exposure light pulses from the light source simultaneously with the camera exposure, and After providing the exposure light pulse, a dummy light pulse is provided that does not overlap with the camera exposure.

2. The electronic device according to claim 1, wherein: The light source includes at least one light emitting diode.

3. The electronic device according to claim 1 or 2, wherein: The light source also includes an at least 20 kHz pulse width modulator configured to adjust pulse intensity.

4. An electronic device according to any preceding claim, wherein: The communication device is a wired communication device.

5. An electronic device according to any preceding claim, wherein: The exposure light pulse has a brightness of at least 500 lux.

6. A method of providing light to an object, the method comprising: receiving a timing signal from a camera, wherein the timing signal includes an exposure timing of the camera exposure; providing an exposure light pulse concurrently with at least a portion of an exposure of the camera; and A dummy light pulse is provided after the exposure light pulse, the dummy light pulse being asynchronous with any camera exposure and having a dead time between the exposure light pulse and the dummy light pulse.

7. The method according to claim 6, wherein: The timing signal includes an exposure duration, and the exposure light pulse has an exposure light pulse duration that is longer than the exposure duration.

8. The method according to claim 6 or 7, wherein: The timing signal includes a frame time between exposures, and the dummy light pulses begin at equal intervals within the frame time.

9. The method according to claim 8, wherein: The dummy light pulse is a first dummy light pulse, and the method further includes providing a second dummy light pulse at a second equal interval after the first dummy light pulse.

10. The method according to any one of claims 6 to 9, wherein: The total duty cycle of the light source in the frame time is at least 20%.

11. The method according to any one of claims 6 to 10, wherein: The timing signal includes a frame time between exposures, and the method further includes providing a second exposure light pulse after the frame time.

12. The method according to any one of claims 6 to 11, wherein: The exposure light pulse has an exposure light intensity, and the dummy light pulse has a dummy light intensity, and the exposure light intensity and the dummy light intensity are equal.

13. The method according to any one of claims 6 to 12, wherein: The dead time does not exceed 15 milliseconds.

14. The method according to any one of claims 6 to 13, wherein: The exposure light pulse has an exposure duration, and the dummy light pulse has a dummy light duration, and the exposure duration and the dummy light duration are equal.

15. The method according to claim 14, wherein: The dummy light pulse is a first dummy light pulse, and the method further includes providing a second dummy light pulse after the first dummy light pulse, wherein the second dummy light pulse has a second dummy light duration, and the dummy light duration and the second dummy light duration are equal.

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