Electronic device and method for video synchronization

Abstract

An electronic device is provided that includes a circuit. The circuit generates a synchronization signal. The circuit controls activation of one or more light emitting devices based on the synchronization signal to generate a pattern of alternating light pulses. The circuit further obtains a plurality of videos of the pattern of alternating light pulses from a plurality of imaging devices, the one or more light emitting devices being positioned within a field of view of each of the plurality of imaging devices. The circuit determines a frame in each of the plurality of videos that includes a particular portion of the pattern of alternating light pulses. The determined frames in each of the plurality of videos correspond to the same moment in time. The circuit synchronizes the plurality of videos based on the determination.

Description

[Technical Field]

[0001] [CROSS-REFERENCE / INCORPORATION BY REFERENCE TO RELATED APPLICATIONS]

[0001] This application claims the benefit of priority to U.S. Patent Application No. 17 / 481,739, filed with the United States Patent Office on September 22, 2021. Each of the above applications is incorporated herein by reference in its entirety.

[0002]

[0002] Various embodiments of the present disclosure relate to video synchronization. More particularly, various embodiments of the present disclosure relate to electronic devices and methods for video synchronization. [Background technology]

[0003]

[0003] Professionals in various media industries, such as the entertainment and mass communications industries, may use multiple cameras to record a scene (e.g., video). For example, multiple cameras may be used to record a scene from different viewpoints, allowing the scene to be captured and / or viewed from multiple perspectives. These cameras may begin capturing video of the scene at different start times and may record video of the scene independently of each other, as the cameras may not be synchronized to begin capturing at the same time. Traditionally, a clapperboard has been used to indicate the beginning of a scene and to synchronize images and audio of the scene during video production. However, these conventional techniques may be inaccurate or ineffective for synchronizing video when other sounds indistinguishable from the sound of the clapperboard are recorded in the scene. In some cases, synchronization cables may be utilized to physically connect multiple cameras to synchronize the video recorded by each of the multiple cameras. However, the physical connection of multiple cameras through synchronization cables may not be practical in situations where the cameras are mounted on moving objects (e.g., separate mobile rigs or vehicles). Therefore, hardware solutions may be impractical to use for video synchronization when the cameras are moving.

[0004]

[0004] Further limitations and disadvantages of conventional methods will become apparent to those skilled in the art by comparing the described system with certain aspects of the present disclosure illustrated in the remainder of this application with reference to the drawings. Summary of the Invention [Problem to be solved by the invention]

[0005]

[0005] An electronic device and method for video synchronization is provided, substantially as shown in and / or described in connection with at least one of the figures, and more fully set forth in the claims.

[0006]

[0006] These and other features and advantages of the present disclosure can be understood by considering the following detailed description of the disclosure in conjunction with the accompanying drawings in which like elements are designated by like reference numerals throughout. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram illustrating an exemplary network environment for video synchronization, according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a block diagram illustrating an exemplary electronic device for video synchronization, according to an embodiment of the present disclosure. [Figure 3] FIG. 2 illustrates exemplary synchronization signals for video synchronization, according to an embodiment of the present disclosure. [Figure 4] FIG. 2 illustrates synchronization signal detection for video synchronization according to an embodiment of the present disclosure. [Figure 5] 1A and 1B illustrate detection of frames corresponding to particular portions of a synchronization signal for video synchronization according to an embodiment of the present disclosure. [Figure 6A] 1 is a flowchart illustrating an exemplary method for detection of a preamble of a synchronization signal for video synchronization, according to an embodiment of the present disclosure. [Figure 6B]1 is a flowchart illustrating an exemplary method for detection of a preamble of a synchronization signal for video synchronization, according to an embodiment of the present disclosure. [Figure 7] 1 is a flowchart illustrating an exemplary method for video synchronization, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008]

[0014] The implementations described below can be found in the disclosed electronic devices and methods for video synchronization. An exemplary aspect of the present disclosure provides an electronic device for synchronizing multiple videos of a scene captured by multiple imaging devices (e.g., cameras). The electronic device can be configured to generate a synchronization signal. In some embodiments, the synchronization signal can include a preamble of a first duration and a sequence of alternating on / off pulses of a second duration. The electronic device can be further configured to control the driving of one or more light-emitting devices (e.g., light-emitting diodes (LEDs) or LED strips) based on the synchronization signal to generate a pattern of alternating light pulses. The one or more light-emitting devices can be positioned within the field of view of each of the multiple imaging devices (e.g., in front of a lens). For example, the one or more light-emitting devices can be positioned in front of each imaging device of the multiple imaging devices at or before the capture of the scene. According to an embodiment, the one or more light emitting devices can be switched on for a first duration based on the preamble and can be alternately switched on and off for a second duration based on a sequence of alternating on / off pulses. The electronic device can be configured to acquire, from a plurality of imaging devices, a plurality of videos of the patterns of alternating light pulses generated by the one or more light emitting devices.

[0009]

[0015] The electronic device can be configured to determine a frame in each video of the plurality of videos that includes a particular portion of the pattern of alternating light pulses (e.g., a start light pulse or an end light pulse). The determined frame in each video of the plurality of videos corresponds to the same temporal instant (e.g., the same wall clock time). According to an embodiment, the particular portion of the pattern of alternating light pulses can include one of the start light pulse of the pattern of alternating light pulses or the end light pulse of the pattern of alternating light pulses. The electronic device can synchronize the plurality of videos based on the determination of a frame in each video of the plurality of videos that can correspond to the particular portion of the pattern of alternating light pulses (e.g., the end light pulse). Thus, the electronic device can improve synchronization accuracy by automatically synchronizing the plurality of videos from the plurality of imaging devices based on the pattern of alternating light pulses that corresponds to the synchronization signal.

[0010]

[0016] In some embodiments, after generating the pattern of alternating light pulses, one or more light-emitting devices can be removed from the field of view of each of the multiple imaging devices. In such a case, the multiple imaging devices can continue capturing the scene without interference from the one or more light-emitting devices. Thus, the electronic device can synchronize multiple videos from multiple imaging devices in situations where the multiple imaging devices may be mounted on a moving object (such as a separate mobile rig or vehicle). The electronic device can further enable synchronization of multiple videos during production based on the pattern of alternating light pulses corresponding to a synchronization signal, thereby eliminating the need for a hardware solution or the need to physically connect multiple imaging devices via synchronization cables to synchronize the multiple videos.

[0011]

[0017] In some embodiments, the sequence of alternating on / off pulses can include on pulses of a first time interval that can be alternating with off pulses of a second time interval. The electronic device can be configured to set the first duration of the preamble based on a frame rate of each video of the plurality of videos. The first duration of the preamble can be longer than each of the first time interval of the on pulses and the second time interval of the off pulses. The electronic device can utilize a synchronization signal preamble (e.g., a long pulse) before the sequence of alternating on / off pulses (e.g., short pulses) to reduce false positives in synchronization signal detection, thereby further improving the accuracy of synchronization of multiple videos and providing a reliable technique for synchronizing multiple videos.

[0012]

[0018] FIG. 1 is a block diagram illustrating an exemplary network environment for video synchronization, according to an embodiment of the present disclosure. Referring to FIG. 1, network environment 100 is shown. In network environment 100, an electronic device 102 is shown. Network environment 100 also includes one or more lighting devices 104, such as a first lighting device 104A, a second lighting device 104B, ..., an Nth lighting device 104N. Network environment 100 also includes a plurality of imaging devices 106, such as a first imaging device 106A, a second imaging device 106B, ..., an Nth imaging device 106N. Network environment 100 also includes a communications network 108. Electronic device 102, one or more lighting devices 104, and the plurality of imaging devices 106 can be communicatively coupled to each other via communications network 108. 1 illustrates first lighting device 104A, second lighting device 104B, and Nth lighting device 104N, the present disclosure is not limited in this respect. In some embodiments, network environment 100 may include a single lighting device (such as first lighting device 104A) within the field of view of each of multiple imaging devices 106 without departing from the scope of the present disclosure.

[0013]

[0019] The electronic device 102 may include suitable logic, circuitry, and interfaces that may be configured to generate a synchronization signal, control driving of one or more light emitting devices 104 based on the synchronization signal to generate the pattern of alternating light pulses, acquire a plurality of videos of the pattern of alternating light pulses from the plurality of imaging devices 106, determine a frame in each of the plurality of videos that corresponds to a particular portion of the pattern of alternating light pulses, and synchronize the plurality of videos based on the determination. The electronic device 102 may be further configured to acquire a frame rate (e.g., 30 frames per second) of each of the plurality of videos from the plurality of imaging devices 106. The electronic device 102 may be further configured to set a first duration (e.g., 1 second) or length (e.g., 30 frames) of a preamble, a first time interval of an on-pulse of the pattern of alternating light pulses, and a second time interval of an off-pulse of the pattern of alternating light pulses based on the acquired frame rate of each of the plurality of videos. The electronic device 102 is further configured to run one or more algorithms on the plurality of videos to determine frames in each of the plurality of videos that correspond to particular portions of the pattern of alternating light pulses. Examples of the electronic device 102 may include, but are not limited to, a computing device, a smartphone, a cellular phone, a mobile phone, a gaming device, a mainframe machine, a server, a computer workstation, a microcontroller, and / or any consumer electronics (CE) device capable of driving and controlling one or more lighting devices 104 and image processing of the plurality of videos. In some embodiments, the electronic device 102 may include separate circuitry and interfaces for driving and controlling the one or more lighting devices 104 and processing the plurality of videos.

[0014]

[0020] The multiple imaging devices 106 may include suitable logic, circuitry, and interfaces that may be configured to capture multiple videos, such as multiple videos of a scene. The multiple imaging devices 106 may further be configured to capture multiple videos of alternating light pulse patterns. For example, the multiple imaging devices 106 may capture multiple videos of alternating light pulse patterns prior to capturing a scene. In some embodiments, the multiple imaging devices 106 may begin capturing the multiple videos at different start times and record the multiple videos independently of each other. The multiple imaging devices 106 may store and transmit the multiple videos to the electronic device 102 for processing (e.g., synchronization). Examples of the multiple imaging devices 106 may include, but are not limited to, image sensors, wide-angle cameras, action cameras, closed-circuit television (CCTV) cameras, camcorders, digital cameras, camera phones, time-of-flight cameras (ToF cameras), night vision cameras, and / or other image capture devices.

[0015]

[0021] The one or more light emitting devices 104 may include suitable logic, circuitry, and interfaces that can be configured to generate a pattern of alternating light pulses. The one or more light emitting devices 104 may generate the pattern of alternating light pulses based on a synchronization signal generated by the electronic device 102. For example, the one or more light emitting devices 104 may be switched on based on a preamble and emit a preamble light pulse for a first duration. The one or more light emitting devices 104 may be alternately switched on and off for a second duration based on a sequence of alternating on / off pulses. The one or more light emitting devices 104 may be alternately switched on and off based on a sequence of alternating on / off pulses including on pulses of a first time interval alternating with off pulses of a second time interval. The electronic device 102 may control the driving of the one or more light emitting devices 104 based on the synchronization signal. The electronic device 102 may be connected to the one or more light emitting devices 104 wirelessly or through a wired connection. In some embodiments, the one or more light-emitting devices 104 may be driven by direct current (DC), which may be turned on and off by components of the electronic device 102, such as field-effect transistors (FETs). In some embodiments, the one or more light-emitting devices 104 may be driven by alternating current using an integrated DC converter or rectifier. Examples of the one or more light-emitting devices 104 may include, but are not limited to, light-emitting diodes (LEDs) or LED strips. For example, the LEDs may be LED bulbs, LED light tubes, LED surface-mount devices, and chip-on-board LEDs. In some embodiments, the one or more light-emitting devices 104 may be configured to emit light at a light intensity equal to or greater than a threshold intensity level. In another embodiment, the one or more light-emitting devices 104 may be switchable on and off at a particular frequency or higher based on a plurality of video frame rates.For example, the higher the frame rate of the videos, the higher the switching frequency of one or more of the light emitting devices 104 can be.

[0016]

[0022] The communication network 108 may include a communication medium that enables the electronic device 102, the one or more lighting devices 104, and the multiple imaging devices 106 to communicate with each other. The communication network 108 may be one of a wired connection or a wireless connection. For example, the electronic device 102 may control the operation of the one or more lighting devices 104 through the communication network 108. The electronic device 102 may obtain multiple videos from the multiple imaging devices 106 through the communication network 108. Examples of the communication network 108 may include, but are not limited to, the Internet, a cloud network, a cellular or wireless mobile network (such as Long-Term Evolution and 5G New Radio), a wireless fidelity (Wi-Fi) network, a personal area network (PAN), a local area network (LAN), or a metropolitan area network (MAN). The various devices in the network environment 100 may be configured to connect to the communication network 108 according to various wired and wireless communication protocols. Examples of such wired and wireless communication protocols may include, but are not limited to, at least one of Transmission Control Protocol and Internet Protocol (TCP / IP), User Datagram Protocol (UDP), Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP), ZigBee, EDGE, IEEE 802.11, Light Fidelity (Li-Fi), 802.16, IEEE 802.11s, IEEE 802.11g, multi-hop communication, wireless access point (AP), device-to-device communication, cellular communication protocols, and Bluetooth (BT) communication protocols.

[0017]

[0023] In operation, multiple imaging devices 106 can be positioned at different locations to record a scene, e.g., a video scene. The multiple imaging devices 106 can be positioned to record a scene from different perspectives. In one or more embodiments, the multiple imaging devices 106 can be manually switched on and off. The multiple imaging devices 106 can be switched on to begin capturing multiple videos at different moments in time. For example, a second imaging device 106B can be switched on a few seconds after a first imaging device 106A is switched on. One or more lighting devices 104 can be positioned within the field of view of each of the multiple imaging devices 106. When the multiple imaging devices 106 begin capturing multiple videos, the one or more lighting devices 104 can be positioned within the field of view of each of the multiple imaging devices 106. According to an embodiment, the one or more lighting devices 104 can include LEDs or LED strips. In some embodiments, the distance between each light emitting device (e.g., first light emitting device 104A) of the one or more light emitting devices 104 and a corresponding imaging device (e.g., first imaging device 106A) of the plurality of imaging devices 106 may be less than or equal to 2 feet.

[0018]

[0024] The electronic device 102 can be configured to generate a synchronization signal. For example, the electronic device 102 can receive user input via the I / O device 206 (shown in FIG. 2 ) to generate the synchronization signal. According to one embodiment, the generated synchronization signal can include a preamble of a first duration and a sequence of alternating on / off pulses of a second duration. According to one embodiment, the sequence of alternating on / off pulses can include on pulses of a first time interval that can be alternating with off pulses of a second time interval. The first time interval can be equal to the second time interval. In another embodiment, the first time interval can be different from the second time interval. Details of the generation of the synchronization signal are further described, for example, with reference to FIG. 3 .

[0019]

[0025] The electronic device 102 can control the driving of one or more light emitting devices 104 based on the generated synchronization signal to generate the pattern of alternating light pulses. For example, the electronic device 102 can cause the DC control circuit 208 (shown in FIG. 2 ) to control the driving of the one or more light emitting devices 104. In some embodiments, a sequence of alternating on / off pulses of a second duration can correspond to the pattern of alternating light pulses. The one or more light emitting devices 104 can be switched on based on the preamble to emit preamble light pulses for a first duration. The one or more light emitting devices 104 can be alternately switched on and off for a second duration based on the sequence of alternating on / off pulses. Details of controlling the driving of the one or more light emitting devices 104 are further shown, for example, in FIG. 4 .

[0020]

[0026] According to an embodiment, the circuit 202 can be configured to set a first duration of the preamble based on a frame rate of each video among the plurality of videos. The frame rate can depend on the shutter speed of each imaging device among the plurality of imaging devices 106. In an exemplary embodiment, the frame rate can be 30 frames per second (fps). Based on the frame rate, the first duration of the preamble can be, for example, 1 second. The preamble can include 30 frames of video. In some embodiments, the duration of the preamble can be longer than each of a first time interval of an on pulse and a second time interval of an off pulse of the alternating on / off pulse sequence. In one or more embodiments, the circuit 202 can be configured to set the first time interval of the on pulse and the second time interval of the off pulse based on the frame rate of each video among the plurality of videos. For example, each of the first time interval of the on pulse and the second time interval of the off pulse can be 1 / 30 of a second. Thus, each of the on pulse and the off pulse can correspond to one frame of video.

[0021]

[0027] The multiple imaging devices 106 can capture the alternating light pulse patterns generated by the one or more light emitting devices 104. The electronic device 102 can acquire multiple videos of the alternating light pulse patterns from the multiple imaging devices 106. The multiple videos can include preamble light pulses and the alternating light pulse patterns generated by the one or more light emitting devices 104. Details of acquiring multiple videos are further described, for example, in FIG.

[0022]

[0028] The electronic device 102 may further determine a frame (or frame number) in each video of the plurality of videos that includes a particular portion of the alternating light pulse pattern (such as a starting light pulse or an ending light pulse). The determined frame in each video of the plurality of videos corresponds to the same time instant (e.g., the same wall clock time). The correspondence between the frame number and the particular portion in each video may be arbitrary, as long as the frame number corresponds to the same wall clock time in each video. For example, the particular portion of the alternating light pulse pattern may include one of the starting light pulse of the alternating light pulse pattern or the ending light pulse of the alternating light pulse pattern. For example, the Nth frame of a first video of the plurality of videos and the Mth frame of a second video of the plurality of videos (shown in FIG. 4 ) may correspond to a particular portion of the alternating light pulse pattern. Details of determining the frame are further described, for example, in FIGS. 4 and 5 . For example, each video of the plurality of videos captured by a corresponding imaging device of the plurality of imaging devices 106 includes a sequence of frames. The electronic device 102 can determine the closest frame number corresponding to the same wall clock time for each frame sequence (one frame sequence per imaging device). The electronic device 102 can further synchronize multiple videos based on determining the frame (or frame number) that includes a particular portion (such as a start light pulse or an end light pulse) that corresponds to the same wall clock time. Thus, the electronic device 102 can improve synchronization accuracy by automatically synchronizing multiple videos from multiple imaging devices 106 based on the pattern of alternating light pulses corresponding to the synchronization signal.

[0023]

[0029] In some embodiments, after generating the pattern of alternating light pulses, one or more light emitting devices 104 may be removed from the field of view of each of the multiple imaging devices 106. In such a case, the multiple imaging devices 106 may continue capturing the scene without interference from the one or more light emitting devices 104. Thus, the electronic device 102 may synchronize multiple videos from the multiple imaging devices 106 in situations where the multiple imaging devices 106 may be mounted on moving objects (such as separate mobile rigs or vehicles). The electronic device 102 may further enable synchronization of multiple videos during production based on the pattern of alternating light pulses corresponding to a synchronization signal, thereby eliminating the need for hardware solutions or the need to physically connect the multiple imaging devices 106 via synchronization cables to synchronize the multiple videos.

[0024]

[0030] In an embodiment, the electronic device 102 can be configured to set the first duration of the preamble to be longer than each of the first time interval of the on pulse and the second time interval of the off pulse of the sequence of alternating on / off pulses. The electronic device can utilize a preamble (e.g., a long pulse) before the sequence of alternating on / off pulses (e.g., a short pulse) to reduce false positives in detecting synchronization signals, thereby further improving the accuracy of synchronization of multiple videos.

[0025]

[0031] According to an embodiment, the electronic device 102 can detect a preamble light pulse of a first duration in a first video of the plurality of videos. In one or more embodiments, the electronic device 102 can detect a preamble light pulse of a first duration in a second video of the plurality of videos. The electronic device 102 can synchronize a first video and a second video of the plurality of videos based on the detection of the preamble light pulse in each of the first video and the second video. In some embodiments, the electronic device 102 can detect a pattern of alternating light pulses of a second duration in the first video and the second video following the detection of the preamble light pulse of the first duration. The electronic device 102 can synchronize the first video and the second video based on the detection of the pattern of alternating light pulses in each of the first video and the second video. In another embodiment, the electronic device 102 can detect both a preamble and a pattern of alternating light pulses of a second duration in the first video and the second video. The electronic device 102 can synchronize the first video and the second video based on detecting both the preamble and the alternating light pulse pattern in each of the first video and the second video. Details of detecting the preamble light pulse and the alternating light pulse pattern for synchronization are further described in, for example, Figures 6A and 6B.

[0026]

[0032] 2 is a block diagram illustrating an exemplary electronic device for video synchronization, according to an embodiment of the present disclosure. Referring to FIG. 2, a block diagram 200 of an electronic device 102 is shown. The electronic device 102 may include a circuit 202, a memory 204, an input / output (I / O) device 206, a direct current (DC) control circuit 208, and a network interface 210.

[0027]

[0033] The circuit 202 may include suitable logic, circuits, and / or interfaces that can be configured to execute program instructions associated with different operations to be performed by the electronic device 102. For example, some of the operations may include generating a synchronization signal, controlling the activation of one or more light emitting devices 104 to generate an alternating light pulse pattern, acquiring multiple videos of the alternating light pulse pattern from the multiple imaging devices 106, determining a frame in each of the multiple videos that can correspond to a particular portion of the alternating light pulse pattern, and synchronizing the multiple videos based on the determination. The circuit 202 may include one or more dedicated processing units, which may be implemented as separate processors. In some embodiments, the one or more dedicated processing units may be implemented as an integrated processor or processors that collectively perform the functions of the one or more dedicated processing units. The circuit 202 may be implemented based on several processor technologies known in the art. An example implementation of circuit 202 may be an X86-based processor, a graphics processing unit (GPU), a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC) processor, a complex instruction set computer (CISC) processor, a microcontroller, a central processing unit (CPU), and / or other control circuitry. In one embodiment, circuit 202 may include a first circuit for generating synchronization signals and controlling the driving of one or more light devices 104. Circuit 202 may include a second circuit including a processor for executing one or more algorithms for determining a frame in each video of the plurality of videos that may correspond to a particular portion of the pattern of alternating light pulses, and synchronizing the plurality of videos based on the determination.

[0028]

[0034] The memory 204 may include suitable logic, circuitry, interfaces, and / or code that may be configured to store one or more instructions to be executed by the circuit 202. The memory 204 may be configured to store multiple videos captured by the multiple imaging devices 106. The memory 204 may be configured to store synchronization signals having different patterns of long pulses (e.g., preambles) and short alternating pulses. For example, the memory 204 may store information about a first duration of a preamble and a second duration of a sequence of alternating on / off pulses. In another embodiment, the memory 204 may store information about a first time interval of an on pulse in the sequence of alternating on / off pulses and a second time interval of an off pulse in the sequence of alternating on / off pulses. The memory 204 may be further configured to store threshold intensity levels for detection of the preamble light pulses and the alternating light pulses. In some embodiments, memory 204 can be configured to store one or more algorithms (shown in the flowcharts of FIGS. 6A and 6B ) for detecting a preamble and determining a frame in each of the multiple videos that can correspond to a particular portion of the pattern of alternating light pulses. Example implementations of memory 204 can include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), hard disk drive (HDD), solid state drive (SSD), CPU cache, and / or secure digital (SD) card.

[0029]

[0035] The I / O device 206 may include suitable logic, circuits, and interfaces that can be configured to receive input and provide output based on the received input. For example, the I / O device 206 may receive input from a user for synchronizing multiple videos. The I / O device 206 may include a variety of input and output devices that can be configured to communicate with the circuit 202. Examples of the I / O device 206 include, but are not limited to, a touchscreen, a keyboard, a mouse, a joystick, a microphone, a display device, and a speaker. The I / O device 206 may include a touchscreen display that can receive user input through touch input. The touchscreen may be at least one of a resistive touchscreen, a capacitive touchscreen, or a thermal touchscreen. The touchscreen display may be implemented through several known technologies, such as, but not limited to, liquid crystal display (LCD) display, light-emitting diode (LED) display, plasma display, or organic LED (OLED) display technology, or other display devices.

[0030]

[0036] The DC control circuit 208 may include suitable logic, circuits, and interfaces that may be configured to control the driving of one or more light emitting devices 104 based on a synchronization signal. The DC control circuit 208 may receive a synchronization signal from the circuit 202. The DC control circuit 208 may switch one or more light emitting devices 104 on and off based on the received synchronization signal. Based on switching one or more light emitting devices 104 on and off, the one or more light emitting devices 104 may generate a pattern of alternating light pulses. In an exemplary embodiment, the DC control circuit 208 may include a rectifier and a metal-oxide semiconductor field-effect transistor (MOSFET) that may switch one or more light emitting devices 104 on and off based on the synchronization signal. Although the DC control circuit 208 is shown separate from the circuit 202 in FIG. 2 , the present disclosure is not limited in this respect. Thus, in some embodiments, the DC control circuit 208 may be incorporated into the circuit 202 without departing from the scope of the present disclosure.

[0031]

[0037] The network interface 210 may include suitable logic, circuitry, and / or interfaces that may be configured to facilitate communication between the electronic device 102, the one or more light emitting devices 104, and the plurality of imaging devices 106 over the communications network 108. The network interface 210 may be implemented using various known technologies that support wired or wireless communication between the electronic device 102 and the communications network 108. The network interface 210 may include, but is not limited to, an antenna, a radio frequency (RF) transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a coder-decoder (CODEC) chipset, a subscriber identity module (SIM) card, or a local buffer circuit.

[0032]

[0038] Those skilled in the art will appreciate that the electronic device 102 of Figure 2 may include other suitable components or systems in addition to those illustrated herein for purposes of explaining the functionality and operation of the present disclosure. A detailed description of the other components or systems of the electronic device 102 is omitted from this disclosure for the sake of brevity. The operation of the circuit 202 is further described, for example, in Figures 3-6.

[0033]

[0039] FIG. 3 illustrates an exemplary synchronization signal for video synchronization, according to an embodiment of the present disclosure. The description of FIG. 3 will be provided with reference to elements of FIGS. 1 and 2. Referring to FIG. 3, an exemplary synchronization signal 300 is shown. The synchronization signal 300 may include a preamble 302 and a sequence of alternating on / off pulses 304. The sequence of alternating on / off pulses 304 may include a first off pulse 304A, a first on pulse 304B, a second off pulse 304C, a second on pulse 304D, a third off pulse 304E, and a third on pulse 304F.

[0034]

[0040] The circuit 202 can be configured to generate a synchronization signal 300. According to one embodiment, the generated synchronization signal 300 can include a preamble 302 (e.g., a long on-pulse) of a first duration T1. The synchronization signal 300 can further include, following the preamble 302, a sequence 304 of alternating on / off pulses of a second duration T2. ​​The sequence 304 of alternating on / off pulses can correspond to a pattern of alternating light pulses. The synchronization signal 300 can be a visual synchronization signal or an audio synchronization signal. In one embodiment, the initial few pulses of the synchronization signal 300 before the preamble can be off-pulses.

[0035]

[0041] According to an embodiment, the circuit 202 can be configured to set the first duration T1 of the preamble 302 based on the frame rate of each video of the plurality of videos. In an exemplary implementation, the frame rate (e.g., fps) of each video of the plurality of videos can be predetermined based on the settings of the plurality of imaging devices 106 and can depend on the shutter type (e.g., rolling shutter or global shutter) of the plurality of imaging devices 106. The frame rate can further be set by user input. In one example, the frame rate can be 30 frames per second. Based on the frame rate, the first duration T1 of the preamble can be, for example, 1 second. In such a case, the length of the preamble 302 can be 30 frames.

[0036]

[0042] According to one embodiment, the alternating on / off pulse sequence 304 can include on pulses of a first time interval T3 alternating with off pulses of a second time interval T4. For example, the alternating on / off pulse sequence 304 can include one or more on pulses, such as a first on pulse 304B, a second on pulse 304D, and a third on pulse 304F, each having a first time interval T3. The alternating on / off pulse sequence 304 can further include one or more off pulses, such as a first off pulse 304A, a second off pulse 304C, and a third off pulse 304E, each having a second time interval T4. The positions of the pulses can be such that each on pulse in the alternating on / off pulse sequence 304 can alternate with each off pulse.

[0037]

[0043] In certain embodiments, the first duration T1 of the preamble 302 can be longer than each of the first time interval T3 of the on pulse and the second time interval T4 of the off pulse of the alternating on / off pulse sequence 304. In some embodiments, the first time interval T3 of each on pulse of the alternating on / off pulse sequence 304 can be equal to the second time interval T4 of each off pulse. For example, the first time interval T3 can be in a range of 3 to 15 milliseconds. The second time interval T4 can be in a range of 3 to 15 milliseconds. Thus, the first time interval T3 of the first on pulse 304B, the second on pulse 304D, and the third on pulse 304F can be 10 milliseconds. Similarly, the second time interval T4 of the first off pulse 304A, the second off pulse 304C, and the third off pulse 304E can be 10 milliseconds.

[0038]

[0044] In one or more embodiments, the first time interval T3 of each on pulse in the sequence of alternating on / off pulses 304 can be different from the second time interval T4 of each off pulse. For example, the first time interval T3 can be 10 milliseconds. The second time interval T4 can be 15 milliseconds. Thus, the first time interval T3 of the first on pulse 304B, the second on pulse 304D, and the third on pulse 304F can be 10 milliseconds. Furthermore, the second time interval T4 of the first off pulse 304A, the second off pulse 304C, and the third off pulse 304E can be 15 milliseconds.

[0039]

[0045] In some embodiments, the first time interval T3 of each on pulse can be different from the second time interval T4 of each off pulse. For example, the second time interval T4 of the first off pulse 304A can be 10 milliseconds. The first time interval T3 of the first on pulse 304B can be 12 milliseconds. The second time interval T4 of the second off pulse 304C can be 8 milliseconds. The first time interval T3 of the second on pulse 304D can be 14 milliseconds. The second time interval T4 of the third off pulse 304E can be 11 milliseconds. The first time interval T3 of the third on pulse 304F can be 9 milliseconds.

[0040]

[0046] According to an embodiment, the circuit 202 can be configured to set the first time interval T3 of the on pulse and the second time interval T4 of the off pulse based on the frame rate of each video of the plurality of videos. For example, the frame rate can be 30 frames per second. Each on pulse and each off pulse of the alternating on / off pulse sequence 304 can be a short duration pulse. In one example, the first time interval T3 can be set as 1 / 30 seconds so that each on pulse includes one frame of one video of the plurality of videos. In such a case, the first time interval T3 of the first on pulse 304B, the second on pulse 304D, and the third on pulse 304F can be 1 / 30 seconds, which can be equal to the length of one frame of one video of the plurality of videos. Similarly, the second time interval T4 of the off pulse can be set based on the frame rate of each video of the plurality of videos. In another embodiment, in the case of a rolling shutter, each on pulse can overlap portions of two adjacent frames of one video of the plurality of videos. For example, each on-pulse can overlap the latter half of a first frame and the former half of a second frame adjacent to the first frame.

[0041]

[0047] In another embodiment, the first time interval T3 can be set as 2 / 30 seconds to allow each on-pulse to overlap two adjacent frames of a video from the plurality of videos. In such a case, the first time interval T3 of the first on-pulse 304B, the second on-pulse 304D, and the third on-pulse 304F can be 1 / 15 seconds, which can be equal to the length of two frames of a video from the plurality of videos. The circuit 202 can generate a preamble for the synchronization signal 300 of any length or duration, and can generate a sequence of alternating on / off pulses 304 of any length or duration, using different time intervals for the on and off pulses to reduce false positives in detecting the synchronization signal 300. The circuit 202 can control the driving of one or more light-emitting devices 104 based on the synchronization signal 300 to generate a pattern of alternating light pulses. In another embodiment, the circuit 202 can control the driving of one or more audio devices based on the synchronization signal 300 to generate a pattern of alternating audio pulses.

[0042]

[0048] FIG. 4 is a diagram illustrating detection of a synchronization signal for video synchronization according to an embodiment of the present disclosure. The description of FIG. 4 will be provided in relation to elements in FIGS. 1-3. Referring to FIG. 4, an exemplary scenario 400 is shown. The exemplary scenario 400 illustrates a synchronization signal 402 for video production, a first video 404, a second video 406, and a user interface (UI) 408. The UI 408 may display an Nth frame 410 of a first video 404 and an Mth frame 412 of a second video 406 of the multiple videos at a synchronization position. The synchronization signal 402 may have a similar configuration to the synchronization signal 300 shown in FIG. 3.

[0043]

[0049] In the exemplary scenario 400, multiple imaging devices 106 may be positioned at different locations to record a scene from different perspectives. According to an embodiment, one or more lighting devices 104 may be positioned within the field of view of each of the multiple imaging devices 106. For example, a first lighting device 104A may be positioned within the field of view of a first imaging device 106A. A second lighting device 104B may be positioned within the field of view of a second imaging device 106B. An Nth lighting device 104N may be positioned within the field of view of an Nth imaging device 106N. In some embodiments, one lighting device of the one or more lighting devices 104 may be positioned within the field of view of all of the multiple imaging devices 106.

[0044]

[0050] According to an embodiment, the distance between each light-emitting device of the one or more light-emitting devices 104 and a corresponding imaging device of the multiple imaging devices 106 can be based on the intensity of the alternating light pulses, the orientation of each imaging device of the multiple imaging devices 106, or the number of one or more light-emitting devices 104 used. In one example, the distance can be less than or equal to two feet. In another example, each light-emitting device of the one or more light-emitting devices 104 can be positioned such that each light-emitting device can be one foot relative to the lens of a corresponding imaging device of the multiple imaging devices 106. One skilled in the art will understand that the scope of the present disclosure is not limited to any particular distance requirement between the one or more light-emitting devices 104 and the multiple imaging devices 106, so long as the image sensor of each of the multiple imaging devices 106 simultaneously receives the pattern of alternating light pulses.

[0045]

[0051] According to some embodiments, the one or more light emitting devices 104 may include LEDs or LED strips. The circuitry 202 may control the driving of the LEDs or LED strips based on the generated synchronization signal 402 (including the preamble 302 and alternating on / off pulse sequence 304 shown in FIG. 3 ) to generate a pattern of alternating light pulses that includes a preamble light pulse. In some embodiments, the DC control circuitry 208 of the electronic device 102 may drive the one or more light emitting devices 104 to generate a pattern of alternating light pulses. The multiple imaging devices 106 may begin capturing multiple videos at different time instants. In some embodiments, the multiple imaging devices 106 may capture the generated pattern of alternating light pulses that includes a preamble light pulse before capturing a scene. After the alternating light pulse pattern ends, the one or more light emitting devices 104 may be removed from the field of view of the multiple imaging devices 106. The multiple imaging devices 106 may then continue capturing the scene after capturing the pattern of alternating light pulses. In one embodiment, the multiple imaging devices 106 can capture still images at regular intervals, where the intervals are different among the multiple imaging devices 106. The intervals can be set to be consistent during the time frame of capture of the pattern of alternating light pulses (i.e., the synchronization pattern) and during the time frame of the subsequent video or captured still images.

[0046]

[0052] According to an embodiment, the circuit 202 can be configured to switch on one or more light-emitting devices 104 to emit preamble light pulses for a first duration based on a preamble (e.g., preamble 302). The preamble light pulses can be long-duration pulses that can be emitted by one or more light-emitting devices 104. Note that the preamble light pulse refers to the first pulse emitted before a pattern of alternating light pulses (i.e., a synchronization pattern) and can include either a single long light pulse (as shown in FIGS. 3 and 4) or more than one pulse. The emitted preamble light pulses can be captured by each imaging device of the plurality of imaging devices 106. At the end of the first duration, the circuit 202 can alternately switch on and off one or more light-emitting devices 104 based on a sequence of alternating on / off pulses (e.g., sequence of alternating on / off pulses 304) to emit the pattern of alternating light pulses for a second duration. The alternating light pulse pattern can be generated by alternately switching one or more light emitting devices 104 on and off. The alternating light pulse pattern can be a preamble followed by short duration pulses emitted by one or more light emitting devices 104. For example, the alternating light pulse pattern can include three or more equally spaced light pulses or can include three or more irregularly spaced light pulses. The alternating light pulse pattern can be captured by each imaging device of the plurality of imaging devices 106.

[0047]

[0053] The circuit 202 can be further configured to acquire multiple videos of a preamble light pulse followed by an alternating pattern of light pulses from the multiple imaging devices 106. For example, the circuit 202 can acquire a first video 404 from a first imaging device 106A and a second video 406 from a second imaging device 106B. The first video 404 and the second video 406 can include a sequence of frames. A first set of frames of each video of the multiple videos can include a preamble light pulse, and a second set of frames of each video of the multiple videos can include the alternating pattern of light pulses generated by one or more light-emitting devices 104.

[0048]

[0054] In an exemplary scenario, the first imaging device 106A may be turned on before the second imaging device 106B. For example, the first imaging device 106A may be turned on a few seconds before the second imaging device 106B is turned on. The time difference between the turning on of the first imaging device 106A and the second imaging device 106B may be due to a difference in performance of the first imaging device 106A and the second imaging device 106B or due to a delay between user inputs. Due to the time difference between the turning on of the first imaging device 106A and the second imaging device 106B of the multiple imaging devices 106, the frames of the first video 404 that may record the pattern of alternating light pulses may differ from the frames of the second video 406 that may record the pattern of alternating light pulses. The circuit 202 can acquire a first set of frames that can include a preamble and a second set of frames that can include a pattern of alternating light pulses recorded by each of the multiple imaging devices 106.

[0049]

[0055] The circuit 202 can be configured to detect a preamble light pulse based on a first set of frames of each video of the plurality of videos. The circuit 202 can detect a pattern of alternating light pulses based on a second set of frames of each video of the plurality of videos. The circuit 202 can then determine a frame in each video of the plurality of videos (e.g., first video 404 and second video 406) that includes a particular portion of the pattern of alternating light pulses (e.g., a start light pulse or an end light pulse). The determined frame in each video of the plurality of videos corresponds to the same time instant (e.g., the same wall clock time). According to an embodiment, the particular portion of the pattern of alternating light pulses can include one of the start light pulse of the pattern of alternating light pulses or the end light pulse of the pattern of alternating light pulses. For example, as shown in FIG. 3, the start light pulse of the pattern of alternating light pulses can be a first off pulse 304A, and the end light pulse of the pattern of alternating light pulses can be a third on pulse 304F.

[0050]

[0056] In one example, the Nth frame 410 may be frame number 147 of the second set of frames of the first video 404 and may include an ending pulse of the alternating light pulse pattern. In one example, the Mth frame 412 may be frame number 226 of the second set of frames of the second video 406 and may include an ending pulse of the alternating light pulse pattern. The third on-pulse 304F of the synchronization signal 402 may correspond to the Nth frame 410 of the first video 404, and the third on-pulse 304F of the synchronization signal 402 may correspond to the Mth frame 412 of the second video 406. The circuit 202 may determine the Nth frame 410 of the first video 404 and the Mth frame 412 of the second video 406, which may correspond to the ending light pulse of the alternating light pulse pattern. The circuit 202 can use the determined Nth frame 410 and the determined Mth frame 412 to obtain a synchronization position between the first video 404 and the second video 406. The difference between the Nth frame 410 and the Mth frame 412 may be referred to as a synchronization offset between the first video 404 and the second video 406.

[0051]

[0057] According to one embodiment, the circuit 202 can detect a preamble light pulse of a first duration in a first set of frames of the plurality of videos. In some embodiments, the circuit 202 can detect a pattern of alternating light pulses of a second duration in the first video 404 and the second video 406 following the detection of the preamble light pulse of the first duration. In some embodiments, the circuit 202 can verify the detection of the pattern of alternating light pulses based on the detection of the preamble light pulse, or vice versa. Details of the detection of the preamble light pulse and the detection of the pattern of alternating light pulses are further illustrated, for example, in FIGS. 6A and 6B. Based on the synchronization of the first video 404 and the second video 406, the circuit 202 can control the UI 408 to display the results of the synchronization. In one embodiment, the circuit 202 can control the UI 408 to display the determined frames (e.g., Nth frame 410 and Mth frame 412) for user confirmation of the synchronization during video production. The UI 408 can be displayed on the I / O device 206 of the electronic device 102. In one example, the circuit 202 can synchronize multiple videos, such as the first video 404 and the second video 406, based on user confirmation.

[0052]

[0058] FIG. 5 is a diagram illustrating detection of frames corresponding to particular portions of a synchronization signal for video synchronization, according to an embodiment of the present disclosure. FIG. 5 will be described with reference to elements of FIGS. 1-4. Referring to FIG. 5, an exemplary scenario 500 is shown. In the exemplary scenario 500, a first video 502 is shown that includes a pattern of preamble light pulses and alternating light pulses corresponding to the synchronization signal 402. In the exemplary scenario 500, a second video 504 is shown that includes a pattern of preamble light pulses and alternating light pulses corresponding to the synchronization signal 402. The first video 502 may be captured by a first imaging device 106A, and the second video 504 may be captured by a second imaging device 106B.

[0053]

[0059] The first video 502 and the second video 504 may start at different time instants. The initial few frames of the first video 502 and the second video 504 may be blank frames when one or more light-emitting devices 104 may be turned off before the emission of the preamble light pulse. In one example, the first video 502 and the second video 504 may be out of sync by a few frames. To synchronize the first video 502 and the second video 504, the circuit 202 may detect the absolute frame number of the ending light pulse of the alternating light pulse pattern for each of the first video 502 and the second video 504. The difference between the absolute frame number of the first video 502 and the absolute frame number of the second video 504 may be referred to as a synchronization offset between the first video 502 and the second video 504. The circuit 202 may synchronize the multiple videos using the detected absolute frame numbers of each video.

[0054]

[0060] The absolute frame number in the first video 502 corresponding to the terminating light pulse of the alternating light pulse pattern may be frame #147. In another example, the absolute frame number in the second video 504 corresponding to the terminating light pulse of the alternating light pulse pattern may be frame #226. The absolute frame number may be determined by detecting the preamble light pulse and alternating light pulse pattern corresponding to the synchronization signal 402 included in the first video 502 and the second video 504. The circuit 202 may synchronize the first video 502 and the second video 504 based on frame #147 of the first video 502 and frame #226 of the second video 504. Details of the detection of the preamble light pulse and alternating light pulse pattern are further described, for example, in Figures 6A and 6B.

[0055]

[0061] FIG. 6A is a flowchart illustrating an exemplary method for detecting a preamble of a synchronization signal for video synchronization, according to an embodiment of the present disclosure. The description of FIG. 6A is provided with reference to elements of FIGS. 1-5. Referring to FIG. 6A, a flowchart 600 is shown. The operations of flowchart 600 may be performed by a computer system, such as electronic device 102 or circuit 202. The operations may begin at 602 and proceed to 604. In an embodiment, circuit 202 may search for a preamble light pulse in a first video 502 based on an algorithm (such as a binary search algorithm). The first video 502 may be captured by a first imaging device 106A, and the second video 504 may be captured by a second imaging device 106B.

[0056]

[0062] At 604, a first frame of a first video 502 of the plurality of videos generated by a first imaging device 106A of the plurality of imaging devices 106 may be selected. According to an embodiment, the circuit 202 may be configured to select the first frame of a first video 502 of the plurality of videos generated by a first imaging device 106A of the plurality of imaging devices 106. The first frame may be one of an initial set of frames of the plurality of frames of the first video 502. For example, the first frame may be selected from the first L frames (L=300) of the plurality of frames of the first video 502. The first L frames of the plurality of frames may include a portion of the preamble light pulse.

[0057]

[0063] At 606, a first amount of light intensity may be determined in a selected first frame of the first video 502. According to an embodiment, the circuit 202 may be configured to determine the first amount of light intensity in a selected first frame of the first video 502. The first amount of light intensity may be determined to search for a frame in the first video 502 that may include a portion of a preamble light pulse.

[0058]

[0064] At 608, it may be determined whether the determined first light intensity amount in the selected first frame is greater than a threshold intensity level. According to an embodiment, the circuit 202 may be configured to determine whether the determined first light intensity amount in the selected first frame is greater than a threshold intensity level. The threshold intensity level may be preset based on the intensity levels of one or more light emitting devices 104. The intensity level of the preamble light pulse and each on pulse of the sequence of alternating on / off pulses 304 may exceed the threshold intensity level. A first light intensity amount greater than the threshold intensity level may indicate the presence of a preamble light pulse or an on pulse of the sequence of alternating on / off pulses 304 in the selected first frame of the first video 502.

[0059]

[0065] At 610, a second frame of the first video 502 may be selected based on a determination that the amount of light intensity in the selected first frame may be greater than a threshold intensity level. According to an embodiment, the circuit 202 may be configured to select the second frame of the first video 502 based on a determination that the amount of light intensity in the selected first frame may be greater than a threshold intensity level. The second frame of the first video 502 may be adjacent to the first frame of the first video 502.

[0060]

[0066] The circuit 202 can select a second frame, which can be a subsequent frame or a preceding frame of the first frame, to detect the presence of the preamble light pulse. The preamble light pulse can be included in more than one frame of the plurality of frames of the first video 502, and selecting the second frame adjacent to the first frame can be effective for detecting the preamble light pulse.

[0061]

[0067] At 612, a third frame of the first video 502 from the plurality of videos may be selected based on the determined first amount of light intensity in the selected first frame being less than a threshold intensity level. According to an embodiment, the circuit 202 may be configured to select the third frame of the first video 502 based on the determination that the first amount of light intensity in the selected first frame may be less than a threshold intensity level. For example, the determined first amount of light intensity in the selected first frame being less than the threshold intensity level may indicate the absence of a preamble light pulse in the selected first frame. The selection of the third frame of the first video 502 may be based on a first duration of the preamble light pulse. The duration between the first frame of the first video 502 and the third frame of the first video 502 may be less than or equal to the first duration of the preamble light pulse. For example, the third frame may be a subsequent frame or a preceding frame of the first frame. After selecting the third frame as the first frame, control may pass to 606 to restart the search for a preamble light pulse in the first video 502 .

[0062]

[0068] For example, the first duration of the preamble light pulse may be 1 second. The duration between the first frame of the first video 502 and the third frame of the first video 502 may be between 0.9 seconds and 1.1 seconds. According to an embodiment, the circuit 202 may be configured to search for a preamble light pulse every N frames of the first video 502, starting from the beginning of the first video 502. The preamble light pulse may include N frames.

[0063]

[0069] In an exemplary scenario, the preamble light pulse may include 30 frames (i.e., N≈30). For example, the frame number of the selected first frame may be 30. The frame number of the selected third frame may be either frame #1 or frame #59 based on the number of frames in the preamble light pulse. In some embodiments, the frame number of the selected third frame may be 58 or 60, which may be a few frames smaller or larger than the number of frames in the preamble light pulse to account for differences in the clock rates of the circuit 202 and the first imaging device 106A. Based on a determination that the first light intensity amount in the selected first frame may be less than a threshold intensity level, the third frame may be selected by skipping a few frames of the first video 502 to enable efficient searching for the preamble light pulse. In some embodiments, the circuit 202 may skip forward or backward one frame at a time to select the third frame and restart searching for the preamble light pulse in the first video 502. Control can pass from 612 to 606, the selected third frame can be treated as the selected first frame, and the amount of light intensity of the selected third frame can be determined and compared to a threshold intensity level.

[0064]

[0070] At 614, a second amount of light intensity may be determined in the selected second frame of the first video 502. According to an embodiment, the circuit 202 may be configured to determine the second amount of light intensity in the selected second frame. The second amount of light intensity may be determined to detect the presence of a preamble light pulse in the first video 502.

[0065]

[0071] At 616, it may be determined whether the determined second light intensity amount is greater than a threshold intensity level. According to an embodiment, the circuit 202 may be configured to determine whether the determined second light intensity amount is greater than a threshold intensity level. A determined second light intensity amount greater than the threshold intensity level may indicate the presence of a preamble light pulse in the selected second frame of the first video 502. Based on a determination that the determined second light intensity amount may be less than the threshold intensity level, control may pass to 612 to restart the search for the preamble light pulse by skipping forward or backward by one or more frames of the first video 502 to select a third frame as the first frame.

[0066]

[0072] At 618, based on a determination that the determined second light intensity amount may be greater than the threshold intensity level, the circuit 202 may compare a third light intensity amount of a subsequent frame of the first video 502 to the threshold intensity level. The circuit 202 may compare the third light intensity amount of a subsequent frame of the first video 502 to the threshold intensity level. Based on a determination that the third light intensity amount of a subsequent frame of the first video 502 may be greater than the threshold intensity level, the circuit 202 may continue comparing the third light intensity amount of a subsequent frame to the threshold intensity level.

[0067]

[0073] 6B is a flowchart illustrating an exemplary method for detecting a preamble of a synchronization signal for video synchronization, according to an embodiment of the present disclosure. The description of FIG. 6B is provided with reference to elements of FIGS. 1-5 and 6A.

[0068]

[0074] At 620, based on determining that the third light intensity amount of the subsequent frame of the first video 502 may be less than the threshold intensity level, the circuit 202 may determine whether the number of frames between the first frame and the subsequent frame having the third light intensity amount less than the threshold intensity level is approximately equal to the length of the preamble light pulse (N frames).

[0069]

[0075] At 622, based on determining that the number of frames of the first video 502 between the first frame and the subsequent frame is less than the length of the preamble light pulse by a threshold number of frames, it can be determined whether a pattern of alternating light pulses (e.g., three on light pulses alternating with three off pulses) is detected after a subsequent frame having a third amount of light intensity less than the threshold intensity level. The circuit 202 can be further configured to determine whether a pattern of alternating light pulses is detected after a subsequent frame having a third amount of light intensity less than the threshold intensity level.

[0070]

[0076] At 624, a preamble light pulse of a first duration may be detected in the first video 502 based on a determination that the number of frames between the first frame and a subsequent frame having a third light intensity amount less than the threshold intensity level is approximately equal to the length of the preamble light pulse. According to an embodiment, the circuit 202 may be configured to detect a preamble light pulse of a first duration based on a determination that the number of frames between the first frame and a subsequent frame having a third light intensity amount less than the threshold intensity level is approximately equal to the length of the preamble light pulse. For example, if the number of frames between the first frame and a subsequent frame in the first video 502 is 27 frames and the length of the preamble is 30 frames, the circuit 202 may allow for some tolerance and may detect a preamble light pulse in a frame between the first frame and a subsequent frame in the first video 502.

[0071]

[0077] At 624, a preamble light pulse of a first duration may be detected in the first video 502 based on a determination that the pattern of alternating light pulses is detected after a subsequent frame having a third light intensity amount less than the threshold intensity level. According to an embodiment, the circuit 202 may be configured to detect a preamble light pulse of the first duration based on a determination that the pattern of alternating light pulses is detected after a subsequent frame having a third light intensity amount less than the threshold intensity level. Based on the detection of the pattern of alternating light pulses following the detection of the preamble light pulse, the circuit 202 may verify the accuracy of the detection of the preamble light pulse and the accuracy of the detection of the synchronization signal 300. On the other hand, based on a determination that the pattern of alternating light pulses is not detected after a subsequent frame having a third light intensity amount less than the threshold intensity level, control may pass to 612 to restart the search for a preamble light pulse in the first video 502.

[0072]

[0078] According to an embodiment, the circuit 202 may be further configured to detect a preamble light pulse of a first duration in a second video 504 of the plurality of videos generated by a second imaging device 106B of the plurality of imaging devices 106. The circuit 202 may synchronize the first video 502 and the second video 504 of the plurality of videos based on detecting the preamble light pulse and the pattern of alternating light pulses in both the first video 502 and the second video 504. Detection of a frame corresponding to the termination light pulse in both the first video 502 and the second video 504 and a synchronization offset may be used to synchronize the first video 502 and the second video 504.

[0073]

[0079] In one embodiment, the circuit 202 can synchronize the multiple videos with an accuracy of one frame length of each video of the multiple videos (e.g., 1 / 30 second for 30 fps recording). If information about the sensor scan rate and rolling or global shutter mechanism is available, the circuit 202 can achieve sub-frame accuracy based on the position of the detected alternating light pulses within the frames of each video of the multiple videos. The circuit 202 can further optimize detection based on the pulse widths (i.e., T3 and T4) of the alternating light pulses detected in the multiple videos.

[0074]

[0080] Figure 7 is a flowchart illustrating an exemplary method for video synchronization, according to an embodiment of the present disclosure. The description of Figure 7 is provided with reference to elements of Figures 1-5, 6A, and 6B. Referring to Figure 7, a flowchart 700 is shown. The operations of flowchart 700 may be performed by a computer system, such as electronic device 102 or circuit 202. Operations may begin at 702 and proceed to 704.

[0075]

[0081] At 704, the synchronization signal 300 may be generated. According to an embodiment, the circuit 202 may be configured to generate the synchronization signal 300. Details of the generation of the synchronization signal 300 are further described, for example, in FIG.

[0076]

[0082] At 706, the driving of one or more light emitting devices 104 may be controlled to generate the pattern of alternating light pulses based on the synchronization signal 300. According to an embodiment, the circuitry 202 may be configured to control the driving of one or more light emitting devices 104 to generate the pattern of alternating light pulses based on the synchronization signal 300. Details of controlling the driving of one or more light emitting devices 104 are further described, for example, in FIG.

[0077]

[0083] At 708, multiple videos of the alternating light pulse pattern can be acquired from multiple imaging devices 106, and one or more light emitting devices 104 can be positioned within the field of view of each of the multiple imaging devices 106. According to an embodiment, circuit 202 can be configured to acquire multiple videos of the alternating light pulse pattern (e.g., first video 404 and second video 406) from multiple imaging devices 106. One or more light emitting devices 104 can be positioned within the field of view of each of the multiple imaging devices 106. Details of acquiring multiple videos are further described, for example, with reference to FIG. 4.

[0078]

[0084] At 710, a frame in each video of the plurality of videos can be determined that can correspond to a particular portion of the synchronization pattern (i.e., the pattern of alternating light pulses). According to an embodiment, the circuit 202 can be configured to determine a frame in each video of the plurality of videos that includes a particular portion of the pattern of alternating light pulses. The determined frame in each video of the plurality of videos corresponds to the same time instant (e.g., the same wall clock time). Details of determining the frame in each video are further described, for example, in FIG. 4.

[0079]

[0085] At 712, the plurality of videos may be synchronized based on the determination. According to an embodiment, the circuit 202 may be configured to synchronize the plurality of videos based on determining a frame in each video of the plurality of videos that may correspond to a particular portion of the pattern of alternating light pulses. Details of synchronizing the plurality of videos are further described, for example, in FIG. 5. Control may proceed to an end.

[0080]

[0086] Although flowchart 700 is shown as individual operations such as 704, 706, 708, 710, and 712, the disclosure is not limited in this respect. Thus, in particular embodiments, such individual operations may be further divided into additional operations, combined into fewer operations, or eliminated, depending on the particular implementation, without departing from the essence of the disclosed embodiments.

[0081]

[0087] Various embodiments of the present disclosure may provide a non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by an electronic device (e.g., electronic device 102), cause the electronic device 102 to perform operations. The operations may include generating a synchronization signal (e.g., synchronization signal 300). The operations may further include controlling the driving of one or more light-emitting devices (e.g., one or more light-emitting devices 104) based on the synchronization signal 300 to generate the alternating light pulse pattern. The operations may further include acquiring multiple videos (e.g., first video 404 and second video 406) of the alternating light pulse pattern from multiple imaging devices (e.g., multiple imaging devices 106). The one or more light-emitting devices 104 may be positioned within a field of view of each of the multiple imaging devices 106. The operations may further include determining a frame (e.g., Nth frame 410 and Mth frame 412) in each video of the multiple videos that includes a particular portion of the alternating light pulse pattern. The determined frame in each video of the plurality of videos corresponds to the same time instant (e.g., the same wall clock time). The operations can further include synchronizing the plurality of videos based on the determination.

[0082]

[0088] An example embodiment of the present disclosure may include an electronic device (e.g., electronic device 102). The electronic device 102 may include circuitry (e.g., circuit 202) that may be configured to generate a synchronization signal (e.g., synchronization signal 300). The circuitry 202 may be further configured to control the driving of one or more light emitting devices (e.g., one or more light emitting devices 104) based on the synchronization signal 300 to generate the pattern of alternating light pulses. The circuitry 202 may be further configured to acquire multiple videos (e.g., first video 404 and second video 406) of the pattern of alternating light pulses from multiple imaging devices (e.g., multiple imaging devices 106). The one or more light emitting devices 104 may be positioned within a field of view of each of the multiple imaging devices 106. The circuitry 202 may be further configured to determine a frame (e.g., Nth frame 410 and Mth frame 412) in each video of the multiple videos that includes a particular portion of the pattern of alternating light pulses. The determined frame in each video of the plurality of videos corresponds to the same time instant (e.g., the same wall clock time). The circuit 202 can be further configured to synchronize the plurality of videos based on the determination.

[0083]

[0089] According to an embodiment, the particular portion of the pattern of alternating light pulses may include one of the starting light pulse of the pattern of alternating light pulses or the ending light pulse of the pattern of alternating light pulses.

[0084]

[0090] According to an embodiment, the generated synchronization signal 300 may include a preamble (e.g., preamble 302) of a first duration and a sequence of alternating on / off pulses of a second duration (e.g., sequence of alternating on / off pulses 304) corresponding to the pattern of alternating light pulses. One or more light-emitting devices 104 may be switched on based on the preamble 302 to emit preamble light pulses for the first duration. One or more light-emitting devices 104 may be alternately switched on and off for the second duration based on the sequence of alternating on / off pulses 304.

[0085]

[0091] According to some embodiments, the sequence of alternating on / off pulses can include on pulses of a first time interval alternating with off pulses of a second time interval. In some embodiments, the first time interval can be equal to the second time interval. In some embodiments, the first time interval can be different from the second time interval.

[0086]

[0092] According to an embodiment, the circuit 202 can be configured to set the first duration of the preamble 302 based on the frame rate of each video of the plurality of videos (e.g., the first video 404 and the second video 406). The first duration of the preamble 302 can be longer than each of the first time interval of the on pulse and the second time interval of the off pulse.

[0087]

[0093] According to an embodiment, the circuit 202 may be further configured to set the first time interval of the on pulse and the second time interval of the off pulse based on the frame rate of each video of the plurality of videos.

[0088]

[0094] According to an embodiment, the circuit 202 can be further configured to detect a preamble light pulse of a first duration. The circuit 202 can further synchronize multiple videos based on the detection of the preamble light pulse.

[0089]

[0095] According to an embodiment, the circuit 202 may be further configured to select a first frame of a first video 404 from the plurality of videos generated by a first imaging device 106A from the plurality of imaging devices 106. The circuit 202 may further determine a first amount of light intensity in the selected first frame of the first video 404. The circuit 202 may select a second frame of the first video 404 generated by the first imaging device 106A. The selection of the second frame may be based on the determined first amount of light intensity in the selected first frame being greater than a threshold intensity level. The second frame of the first video 404 may be adjacent to the first frame. The circuit 202 may further determine whether a second amount of light intensity in the selected second frame is greater than the threshold intensity level. The circuit 202 may compare a third amount of light intensity in a subsequent frame of the first video 404 with the threshold intensity level. The comparison may be based on the determined second amount of light intensity in the second frame being greater than the threshold intensity level. The circuit 202 can determine whether the number of frames between the first frame and a subsequent frame having a third light intensity amount less than the threshold intensity level is equal to the length of the preamble light pulse. The circuit 202 can detect a preamble light pulse of the first duration based on a determination that the number of frames between the first frame and the subsequent frame is equal to the length of the preamble light pulse.

[0090]

[0096] According to an embodiment, the circuit 202 may be further configured to detect a pattern of alternating light pulses of a second duration in the first video 404 following detection of the preamble light pulse of the first duration.

[0091]

[0097] According to an embodiment, the circuit 202 may be further configured to select a third frame of the first video 404 from the plurality of videos based on the determined first amount of light intensity in the selected first frame being less than a threshold intensity level. The selection of the third frame of the first video 404 may be based on a first duration of the preamble light pulse. The duration between the first frame of the first video 404 and the third frame of the first video 404 may be less than or equal to the first duration of the preamble light pulse.

[0092]

[0098] According to an embodiment, the circuit 202 may be further configured to detect a preamble light pulse of the first duration in a second video 406 of the plurality of videos generated by a second imaging device 106B of the plurality of imaging devices 106. The circuit 202 may further synchronize the first video 404 and the second video 406 of the plurality of videos based on the detection of the preamble light pulse in the first video 404 and the second video 406.

[0093]

[0099] According to an embodiment, the circuit 202 may be further configured to search for a preamble light pulse from the beginning of a first video 404 of the plurality of videos every N frames of the first video 404. The preamble light pulse may include N frames.

[0094]

[0100] According to an embodiment, the distance between each light emitting device of the one or more light emitting devices 104 and a corresponding image capturing device of the plurality of image capturing devices 106 may be less than or equal to two feet.

[0095]

[0101] According to an embodiment, the one or more light emitting devices 104 may include one of a light emitting diode (LED) or an LED strip.

[0096]

[0102] The present disclosure can be implemented in the form of hardware or in the form of a combination of hardware and software. The present disclosure can be implemented in a centralized manner in at least one computer system, or in a distributed manner where different elements can be distributed across several interconnected computer systems. Any computer system or other apparatus adapted to perform the methods described herein can be suitable. The combination of hardware and software can be a general-purpose computer system including a computer program that, when loaded and executed, can control the computer system to perform the methods described herein. The present disclosure can be implemented in the form of hardware including portions of integrated circuits that also perform other functions.

[0097]

[0103] The present disclosure may also be embodied in a computer program product, which includes all features that enable the implementation of the methods described herein and which is capable of executing these methods when loaded into a computer system. A computer program in this context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having information processing capabilities to perform a particular function, either directly, or after a) conversion into another language, code or notation, or b) reproduction in a different content form, or both.

[0098]

[0104] While the present disclosure has been described with reference to several embodiments, those skilled in the art will recognize that various modifications can be made and equivalents substituted without departing from the scope of the disclosure. Additionally, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope of the disclosure. Therefore, it is not intended that the disclosure be limited to the particular embodiments disclosed, but rather, it is intended to include all embodiments falling within the scope of the appended claims. [Explanation of symbols]

[0099] 100 Network Environment 102 Electronic Devices 104 one or more light emitting devices 104 104A First Light-Emitting Device 104B Second Light-Emitting Device 104N Nth light-emitting device 106 Multiple imaging devices 106A First imaging device 106B Second imaging device 106N Nth imaging device 108 Communication Network 200 Block Diagram 202 circuits 204 memory 206 Input / Output (I / O) Devices 208 Direct Current (DC) Control Circuit 210 Network Interface 300 Sync Signal 302 Preamble 304 Alternating On / Off Pulse Sequence 304A First Off Pulse 304B First On-Pulse 304C Second Off Pulse 304D Second On-Pulse 304E Third Off Pulse 304F Third On-Pulse T1 First duration T2 Second duration T3 First time interval T4 Second time interval 400 Example Scenarios 402 Synchronization Signal 404 First Video 406 Second Video 408 User Interface (UI) 410 Nth Frame 412 Frame M 500 Example Scenarios 502 1st Video 504 Second Video 600 Flowchart 602 start 604 selects a first frame of a first video of the plurality of videos generated by a first imaging device of the plurality of imaging devices. 606 Determine the amount of light intensity at the selected frame of the first video 608 Is the determined light intensity amount greater than the threshold intensity level? 610 selects a second frame of the first video generated by the first imaging device 612 Select the third frame of the first video of multiple videos 614 Determining the amount of light intensity in a selected second frame of the first video 616 Is the determined light intensity amount greater than the threshold intensity level? 618 Is the amount of light intensity in the subsequent frame greater than the threshold intensity level? 620 Is the number of frames between the first frame and the subsequent frame approximately equal to the length of the preamble light pulse? 622 Was a pattern of alternating light pulses detected after the subsequent frame? 624 detects a preamble light pulse of the first duration 700 Flowchart 702 Start 704 sync signal generation 706 Controlling the driving of one or more light emitting devices based on a synchronization signal to generate a pattern of alternating light pulses 708. Acquire a plurality of videos of the alternating light pulse pattern from a plurality of imaging devices, wherein one or more light emitting devices are positioned within the field of view of each of the plurality of imaging devices. 710 determining a frame in each of the plurality of videos that corresponds to a particular portion of the pattern of alternating light pulses; 712 Decision-Based Synchronization of Multiple Videos

Claims

1. 1. An electronic device comprising: generating a synchronization signal; controlling activation of one or more light emitting devices based on the synchronization signal to generate a pattern of alternating light pulses; acquiring a plurality of videos of the alternating light pulse pattern from a plurality of imaging devices, wherein the one or more light emitting devices are positioned within a field of view of each of the plurality of imaging devices; determining a frame in each video of the plurality of videos that includes a particular portion of the pattern of alternating light pulses, wherein the determined frame in each video of the plurality of videos corresponds to the same instant in time; and synchronizing the plurality of videos based on the determination; and [0023] including circuitry configured to: the generated synchronization signal includes a preamble of a first duration and a sequence of alternating on / off pulses of a second duration corresponding to the pattern of alternating light pulses; the one or more light-emitting devices are switched on based on the preamble to emit a preamble light pulse for the first duration; the one or more light-emitting devices are alternately switched on and off for the second duration based on the sequence of alternating on / off pulses; configured to set the first duration of the preamble based on a frame rate of each video of the plurality of videos; the first duration of the preamble is longer than the second duration corresponding to the pattern of alternating light pulses; An electronic device characterized by:

2. 2. The electronic device of claim 1, wherein the particular portion of the pattern of alternating light pulses includes one of a starting light pulse of the pattern of alternating light pulses or an ending light pulse of the pattern of alternating light pulses.

3. the sequence of alternating on / off pulses includes on pulses of a first time interval alternating with off pulses of a second time interval; the first time interval is equal to the second time interval; 2. The electronic device according to claim 1 .

4. the sequence of alternating on / off pulses includes on pulses of a first time interval alternating with off pulses of a second time interval; the first time interval is different from the second time interval; 2. The electronic device according to claim 1 .

5. The first duration of the preamble is longer than each of the first time interval of the on-pulse and the second time interval of the off-pulse.

5. The electronic device according to claim 4.

6. 5. The electronic device of claim 4, wherein the circuitry is further configured to set the first time interval of the on pulses and the second time interval of the off pulses based on a frame rate of each video of the plurality of videos.

7. The circuit comprises: detecting the preamble light pulse of the first duration; synchronizing the plurality of videos based on the detection of the preamble light pulse; further configured as follows:

2. The electronic device according to claim 1 .

8. The circuit comprises: selecting a first frame of a first video of the plurality of videos generated by a first imaging device of the plurality of imaging devices; determining a first amount of light intensity in the selected first frame of the first video; selecting a second frame of the first video generated by the first imaging device, wherein the selection of the second frame is based on the determined first amount of light intensity in the selected first frame being greater than a threshold intensity level, and the second frame of the first video is adjacent to the first frame; determining whether a second amount of light intensity in the selected second frame is greater than the threshold intensity level; comparing a third amount of light intensity of a subsequent frame of the first video with the threshold intensity level, the comparison being based on the determined second amount of light intensity in the second frame being greater than the threshold intensity level; determining whether the number of frames between the first frame and the subsequent frame having the third amount of light intensity less than the threshold intensity level is equal to a length of the preamble light pulse; detecting the preamble light pulse of the first duration based on determining that the number of frames between the first frame and the subsequent frame is equal to a length of the preamble light pulse; configured to:

2. The electronic device according to claim 1 .

9. The circuit comprises: detecting the pattern of alternating light pulses of the second duration in the first video after the subsequent frame having the third amount of light intensity less than the threshold intensity level based on determining that the number of frames between the first frame and the subsequent frame is less than a length of the preamble light pulse; detecting the preamble light pulse of the first duration based on detecting the pattern of alternating light pulses. further configured as follows:

9. The electronic device according to claim 8.

10. the circuitry is further configured to select a third frame of the first video of the plurality of videos based on the determined first amount of light intensity in the selected first frame being less than the threshold intensity level; selecting the third frame of the first video based on the first duration of the preamble light pulse; a duration between the first frame of the first video and the third frame of the first video is less than or equal to the first duration of the preamble light pulse; 9. The electronic device according to claim 8.

11. The circuit comprises: detecting the preamble light pulse of the first duration in a second video of the plurality of videos generated by a second imaging device of the plurality of imaging devices; synchronizing the first video and the second video of the plurality of videos based on detection of the preamble light pulse in the first video and the second video; further configured as follows:

9. The electronic device according to claim 8.

12. the circuitry is further configured to search for the preamble light pulse every N frames of a first video of the plurality of videos from a start of the first video; the preamble optical pulse includes N frames; 2. The electronic device according to claim 1 .

13. 10. The electronic device of claim 1, wherein the distance between each light-emitting device of the one or more light-emitting devices and a corresponding imaging device of the plurality of imaging devices is less than or equal to 2 feet.

14. 10. The electronic device of claim 1, wherein the one or more light emitting devices comprise one of a light emitting diode (LED) or an LED strip.

15. 1. A method comprising: generating a synchronization signal; controlling activation of one or more light emitting devices based on the synchronization signal to generate a pattern of alternating light pulses; acquiring a plurality of videos of the alternating light pulse pattern from a plurality of imaging devices, wherein the one or more light emitting devices are positioned within a field of view of each of the plurality of imaging devices; determining a frame in each video of the plurality of videos that includes a particular portion of the pattern of alternating light pulses, the determined frame in each video of the plurality of videos corresponding to the same instant in time; synchronizing the plurality of videos based on the determination; Including, the generated synchronization signal includes a preamble of a first duration and a sequence of alternating on / off pulses of a second duration corresponding to the pattern of alternating light pulses; the one or more light-emitting devices are switched on based on the preamble to emit a preamble light pulse for the first duration; the one or more light-emitting devices are alternately switched on and off for the second duration based on the sequence of alternating on / off pulses; setting the first duration of the preamble based on a frame rate of each video of the plurality of videos; the first duration of the preamble is longer than the second duration corresponding to the pattern of alternating light pulses; A method characterized by:

16. 16. The method of claim 15, wherein the particular portion of the pattern of alternating light pulses includes one of a starting light pulse of the pattern of alternating light pulses or an ending light pulse of the pattern of alternating light pulses.

17. The sequence of alternating on / off pulses includes on pulses of a first time interval alternating with off pulses of a second time interval; the first duration of the preamble is longer than each of the first time interval of the on-pulse and the second time interval of the off-pulse; 16. The method of claim 15.

18. A non-transitory computer-readable medium having stored thereon computer-executable instructions that, when executed by an electronic device, cause the electronic device to perform operations, the operations including: generating a synchronization signal; controlling activation of one or more light emitting devices based on the synchronization signal to generate a pattern of alternating light pulses; acquiring a plurality of videos of the alternating light pulse pattern from a plurality of imaging devices, wherein the one or more light emitting devices are positioned within a field of view of each of the plurality of imaging devices; determining a frame in each video of the plurality of videos that includes a particular portion of the pattern of alternating light pulses, wherein the determined frame in each video of the plurality of videos corresponds to the same instant in time; and synchronizing the plurality of videos based on the determination; and Including, the generated synchronization signal includes a preamble of a first duration and a sequence of alternating on / off pulses of a second duration corresponding to the pattern of alternating light pulses; the one or more light-emitting devices are switched on based on the preamble to emit a preamble light pulse for the first duration; the one or more light-emitting devices are alternately switched on and off for the second duration based on the sequence of alternating on / off pulses; setting the first duration of the preamble based on a frame rate of each video of the plurality of videos; the first duration of the preamble is longer than the second duration corresponding to the pattern of alternating light pulses; 1. A non-transitory computer-readable medium comprising:

Images