Patent Publication Number: US-2023135230-A1

Title: Electronic device and method for spatial synchronization of videos

Description:
REFERENCE 
     None. 
     FIELD 
     Various embodiments of the disclosure relate to video synchronization. More specifically, various embodiments of the disclosure relate to an electronic device and a method for spatial synchronization of videos. 
     BACKGROUND 
     Typically, multiple imaging devices, such as cameras may be utilized to record multiple videos of an object or a scene from different viewpoints. Such recorded videos may be utilized in various industries for different purposes. For example, the recorded videos may be utilized for photogrammetry applications. In another example, the recorded video may be utilized for applications, such as scene reconstruction for augmented reality, virtual reality, three-dimensional (3D) object detection or motion capturing. Generally, the photogrammetry applications and computer graphics applications may require information about extrinsic parameters of each camera of the multiple cameras to accurately process the recorded videos. The extrinsic parameters of each camera may be determined by spatial synchronization (or calibration) of the multiple cameras. Conventional methods for the spatial synchronization may include manual execution of a labor-intensive setup, that may be difficult to implement and may not guarantee accuracy in the calibration of the multiple cameras. Moreover, conventional methods may utilize measurement targets, such as checkerboard patterned-boards and identifiable markers for the spatial synchronization of the multiple cameras, use of which may be time-consuming and inefficient to achieve the spatial synchronization of the multiple cameras. 
     Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of described systems with some aspects of the present disclosure, as set forth in the remainder of the present application and with reference to the drawings. 
     SUMMARY 
     An electronic device and a method for spatial synchronization of videos, are provided substantially as shown in, and/or described in connection with, at least one of the figures, as set forth more completely in the claims. 
     These and other features and advantages of the present disclosure may be appreciated from a review of the following detailed description of the present disclosure, along with the accompanying figures in which like reference numerals refer to like parts throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram that illustrates an exemplary network environment for spatial synchronization of videos, in accordance with an embodiment of the disclosure. 
         FIG.  2    is a block diagram that illustrates an exemplary electronic device for spatial synchronization of videos, in accordance with an embodiment of the disclosure. 
         FIG.  3    is a diagram that illustrates an exemplary synchronization signal, in accordance with an embodiment of the disclosure. 
         FIGS.  4 A- 4 C  collectively illustrate a diagram for exemplary operations for spatial synchronization of videos, in accordance with an embodiment of the disclosure. 
         FIG.  5    is a flowchart that illustrates an exemplary method for spatial synchronization of videos, in accordance with an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following described implementations may be found in the disclosed electronic device and a method for spatial synchronization of a plurality of images (or videos) and capturing devices. Exemplary aspects of the disclosure provide an electronic device for the spatial synchronization of a plurality of imaging devices (for example, but are not limited to, digital cameras, video cameras and cameras mounted on drones and vehicles). The plurality of imaging devices may be utilized to record an object or a scene from a plurality of viewpoints. The electronic device may be configured to determine initial three-dimensional (3D) coordinates of a lighting device communicably coupled to the electronic device. The lighting device may include a grid of lights and an edge light. The determined 3D coordinates may be for example, global Cartesian coordinates of the lighting device in space. The electronic device may further control an emission of light from the lighting device based on one or more control signals. For example, the emission of light from one or more of the grid of lights and the edge light may be controlled. The emitted light may include at least one of a pattern of alternating light pulses or a continuous light pulse. The electronic device may further control the plurality of imaging devices to capture a first plurality of images that may include information about the emitted light. For example, the lighting device may be in a field-of-view of a respective imaging device of the plurality of imaging devices, while the plurality of imaging devices captures the first plurality of images. 
     In accordance with an embodiment, the one or more control signals may include a synchronization signal. The electronic device may control the emission of the light from the lighting device based on the synchronization signal to determine a first set of images of the first plurality of images. The electronic device may determine the first set of images of the first plurality of images that may include information about the pattern of alternating light pulses included in the emitted light. For example, the first set of images may include information about an ON pulse pattern and an OFF pulse pattern of the pattern of alternating light pulses. 
     The electronic device may further determine a center of each light of the grid of lights of the lighting device in a first set of frames of the first set of images. The first set of frames may include the ON pattern of the pattern of alternating light pulses. Based on the determined 3D coordinates, and the information about the pattern of alternating light pulses included in the emitted light and included in the first plurality of images, the electronic device may estimate a first rotation value and a first translation value of a plurality of rotation values and a plurality of translation values for each imaging device of the plurality of imaging devices. 
     In accordance with an embodiment, the electronic device may further control a transformation of each imaging device of the plurality of imaging devices for a first time period. For example, the transformation of each imaging device may include at least a rotation or a translation of each imaging device towards the lighting device. Each imaging device may capture a second set of images of the first plurality of images. The electronic device may further determine a center of each light, of the grid of lights of the lighting device, in the second set of images. The second set of images may include information about the emitted light that may include the continuous light pulse. Based on the determined 3D coordinates of the lighting device and the determined center of each light (i.e. of the grid of lights of the lighting device) in the second set of images, the electronic device may estimate a second rotation value and a second translation value of the estimated plurality of rotation values and the plurality of translation values, for each imaging device of the plurality of imaging devices. The electronic device may further apply a simultaneous localization and mapping (SLAM) process for each imaging device, based on the plurality of rotation values and the plurality of translation values, for accurate spatial synchronization of the plurality of imaging devices. 
     In conventional systems, the spatial synchronization (or calibration) of the plurality of imaging devices may require manual execution of a labor-intensive setup, that may be difficult to implement and may not guarantee accuracy in the spatial synchronization. However, the disclosed electronic device may enable calibration of the plurality of imaging devices by use of one single device (such as the lighting device). The light emitted by the lighting device may be utilized to spatially synchronize the plurality of imaging devices, thereby, providing an easy-to-implement setup that may guarantee accuracy in the calibration. Moreover, in the conventional systems, measurement targets, such as checkerboard patterned-boards and identifiable markers may be utilized for the spatial synchronization of the plurality of imaging devices, use of which may be time-consuming and inefficient to achieve the calibration. In contrast, the disclosed electronic device may eliminate a usage of the measurement targets to calibrate the plurality of imaging devices, and may further calibrate the plurality of imaging devices based on the determination of the extrinsic parameters (i.e. rotation and translation) of each imaging device based on the information included in the light emitted by the lighting device. Therefore, the disclosed electronic device may provide a time-effective and efficient spatial synchronization of the plurality of imaging devices. 
       FIG.  1    is a block diagram that illustrates an exemplary network environment for spatial synchronization of videos, in accordance with an embodiment of the disclosure. With reference to  FIG.  1   , there is shown a network environment  100 . The network environment  100  may include an electronic device  102  and a plurality of imaging devices  104 . The plurality of imaging devices  104  may include a first imaging device  104 A, a second imaging device  104 B, and an Nth imaging device  104 N. The network environment  100  may further include a lighting device  106 . The lighting device  106  may include a grid of lights  108 , an edge light  110  and a rotatable stand  112 . The network environment  100  may further include a communication network  114 . The electronic device  102 , the plurality of imaging devices  104  and the lighting device  106  may communicate with each other, via the communication network  114 . 
     The electronic device  102  may include suitable logic, circuitry, interfaces, and/or code that may be configured to spatially synchronize (or calibrate) the plurality of imaging devices  104  and images/videos captured by the plurality of imaging devices  104 . The electronic device  102  may be further configured to generate a synchronization signal that may be utilized for the spatial synchronization of the plurality of imaging devices  104 . Examples of the electronic device  102  may include, but are not limited to, an imaging controller, a photography engine, a movie controller, a computing device, a smartphone, a cellular phone, a mobile phone, a gaming device, a mainframe machine, a server, a computer workstation, and/or a consumer electronic (CE) device. 
     The plurality of imaging devices  104  may include suitable logic, circuitry, and interfaces that may be configured to capture a plurality of images, such as the plurality of images of an object or a scene from different viewpoints. The plurality of imaging devices  104  may be further configured to capture the plurality of images of light emitted by the lighting device  106 . Examples of the plurality of imaging devices  104  may include, but are not limited to, an image sensor, a wide-angle camera, an action camera, a closed-circuit television (CCTV) camera, a camcorder, a digital camera, camera phones, a time-of-flight camera (ToF camera), a night-vision camera, and/or other image capture devices. In some embodiments, one or more imaging devices (such as the Nth imaging device  104 N) of the plurality of imaging devices  104  may be mounted on a drone to capture one or more images of the plurality of images. In an embodiment, one or more imaging devices of the plurality of imaging devices  104  may be mounted with a vehicle (such as a patrol vehicle). 
     The lighting device  106  may include suitable logic, circuitry, and interfaces that may be configured to emit the light that may include at least a pattern of alternating light pulses or a continuous light pulse. The lighting device  106  may be configured to emit the light based on one or more control signals that may include the synchronization signal generated by the electronic device  102 . In an embodiment, the grid of lights  108  of the lighting device  106  may include a plurality of shaped (for example round-shaped) lights arranged in form of a grid or a matrix. In an embodiment, each light of the grid of lights  108  may be a light-emitting diode (LED), a focused light bulb, or any lighting element with a capability to emit a narrow beam light. The edge light  110  of the lighting device  106  may be an LED panel or a bulb/tube-light panel that may be arranged on one or more sides of the lighting device  106 . 
     The communication network  114  may include a communication medium through which the electronic device  102 , the plurality of imaging devices  104 , and the lighting device  106  may communicate with each other. The communication network  114  may be one of a wired connection or a wireless connection. Examples of the communication network  114  may include, but are not limited to, the Internet, a cloud network, 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). Various devices in the network environment  100  may be configured to connect to the communication network  114  in accordance with 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 a Transmission Control Protocol and Internet Protocol (TCP/IP), User Datagram Protocol (UDP), Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP), Zig Bee, 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. 
     In operation, the plurality of imaging devices  104  may be utilized by a user (such as an imaging expert, a movie or video scene director, or a videographer) for different purposes, for example, to record a scene from different viewpoints. In an exemplary scenario, an area may be under surveillance or may be used for recording the scene within the area. The plurality of imaging devices  104  may be utilized by the user to monitor the area under surveillance or to record the scene. For example, the plurality of imaging devices  104  may include the CCTV camera (for example, a first imaging device  104 A), a camera installed in the patrolling vehicle and camera installed in a drone, such as the Nth imaging device  104 N. The electronic device  102  may be configured to determine initial three-dimensional (3D) coordinates of the lighting device  106 . The lighting device  106  may include the grid of lights  108  and the edge light  110 . The determined 3D coordinates may be for example, the global Cartesian coordinates of the lighting device  106  in space. The initial 3D coordinates may include an x-coordinate, a y-coordinate and a z-coordinate. For example, the electronic device  102  may determine the initial 3D coordinates with respect to reference Cartesian coordinates of the lighting device  106  in the space. Details of the determination of the initial 3D coordinates are further described, for example, in  FIG.  4 A . 
     The electronic device  102  may be further configured to control the emission of light from the lighting device  106  based on one or more control signals. For example, the emission of the light from one or more of the grid of lights  108  and the edge light  110  may be controlled based on one or more control signals. In an exemplary scenario, the electronic device  102  may control a transformation (such as a rotation and a translation) of the lighting device  106  towards each imaging device. The emitted light may include at least one of the pattern of alternating light pulses or the continuous light pulse. The electronic device  102  may further control the plurality of imaging devices  104  to capture the first plurality of images that may include information about the emitted light. The electronic device  102  may rotate or translate the lighting device  106  (using the rotatable stand  112  or using any rotatable or movable mechanism on which the lighting device  106  may be installed) towards each of the imaging device, such that the information about the emitted light may be recorded in the first plurality of images by each of the imaging device For example, the lighting device  106  may be in the field-of-view (FOV) of a respective imaging device of the plurality of imaging devices  104 , while the plurality of imaging devices  104  capture the first plurality of images. Details of the control the emission of light from the lighting device  106  based on one or more control signals are further described, for example, in  FIG.  4 A- 4 C . 
     In accordance with an embodiment, the electronic device  102  may generate the synchronization signal. The synchronization signal may include a preamble pulse and a sequence of alternating ON and OFF pulses. The synchronization signal may be generated based on a set of parameters associated with each imaging device of the plurality of imaging devices  104 . The set of parameters may include at least a frame rate of each imaging device of the plurality of imaging devices  104 . Details of the generation of the synchronization signal are further described, for example, in  FIG.  3   . 
     In accordance with an embodiment, the one or more control signals may include or correspond to the generated synchronization signal. Thus, the electronic device  102  may control the emission of the light from the lighting device  106  based on the synchronization signal. In some embodiments, the electronic device  102  may activate the grid of lights  108  of the lighting device  106  to generate an ON pattern of the pattern of alternating light pulses included in the emitted light. The electronic device  102  may further deactivate the grid of lights  108  of the lighting device  106  to generate an OFF pattern of the pattern of alternating light pulses included in the emitted light. Similarly, the electronic device  102  may activate or deactivate the edge light  110  of the lighting device  106 . Details of the control of the emission of the light from the lighting device  106  based on the synchronization signal are further described, for example, in  FIG.  4 A . 
     The electronic device  102  may further determine a first set of images of the first plurality of images that may include information about the pattern of alternating light pulses included in the emitted light. For example, the first set of images may include the information about the ON pulse pattern and the OFF pulse pattern of the pattern of alternating light pulses. The electronic device  102  may further determine a center of each light of the grid of lights  108  in the first set of frames of the first set of images. The first set of frames may include the ON pattern of the pattern of alternating light pulses. Based on the determined 3D coordinates, and the information about the pattern of alternating light pulses included in the emitted light included in the first plurality of images, the electronic device  102  may estimate a first rotation value and a first translation value of a plurality of rotation values and a plurality of translation values of each imaging device. Details of the estimation of the first rotation value and the first translation value are further described, for example, in  FIG.  4 C . 
     In accordance with an embodiment, the electronic device  102  may further control a transformation of each imaging device of the plurality of imaging devices  104  for a first time period. For example, the transformation of each imaging device may include at least the rotation or the translation of each imaging device towards the lighting device  106 . The first time period may correspond to, for example, a few seconds or milliseconds. Each imaging device may capture a second set of images of the first plurality of images. The electronic device  102  may further determine a center of each light, of the grid of lights  108  of the lighting device  106 , in the second set of images. The second set of images may include information about the emitted light that may include the continuous light pulse corresponding to the control signal. In some embodiments, the electronic device  102  may determine a set of features associated with each image of the second set of images. The set of features may be utilized to determine a correspondence between objects in the second set of images for calibration. Details of the capture of the second set of images are further described, for example, in  FIG.  4 C . 
     Based on the determined 3D coordinates of the lighting device  106  and the determined center of each light of the grid of lights  108  in the second set of images, the electronic device  102  may estimate a second rotation value and a second translation value of the estimated plurality of rotation values and the plurality of translation values, for each imaging device of the plurality of imaging devices  104 . In some embodiments, the electronic device  102  may utilize the set of features for estimation of the second rotation value and the second translation value. The second rotation value and the second translation value may be indicative of one or more extrinsic parameters associated with each imaging device of the plurality of imaging devices  104 . Details of the estimation of the second rotation value and the second translation value are further described, for example, in  FIG.  4 C . The electronic device  102  may further apply a simultaneous localization and mapping (SLAM) process for each imaging device, based on the plurality of rotation values and the plurality of translation values, for spatial synchronization of the plurality of imaging devices  104 . Thus, the plurality of imaging devices  104  may be calibrated accurately, by utilization of the lighting device  106 . 
       FIG.  2    is a block diagram that illustrates an exemplary electronic device for spatial synchronization of videos, in accordance with an embodiment of the disclosure. With reference to  FIG.  2   , there is shown a block diagram  200  of the electronic device  102 . The electronic device  102  may include circuitry  202 , a memory  204 , an input/output (I/O) device  206 , a direct current (DC) control circuit  208 , and a network interface  210 . 
     The circuitry  202  may include suitable logic, circuitry, and/or interfaces, that may be configured to execute program instructions associated with different operations to be executed by the electronic device  102 . For example, some of the operations may include control of an emission of light from the lighting device  106 , control the plurality of imaging devices  104 , estimation of a plurality of rotation values and translation values of each imaging device, and spatial synchronization of each imaging device of the plurality of imaging devices  104  based on the estimated plurality of rotation values and translation values. The circuitry  202  may include one or more specialized processing units, which may be implemented as a separate processor. In an embodiment, the one or more specialized processing units may be implemented as an integrated processor or a cluster of processors that perform the functions of the one or more specialized processing units, collectively. The circuitry  202  may be implemented based on a number of processor technologies known in the art. Examples of implementations of the circuitry  202  may be an X86-based processor, a Graphics Processing Unit (GPU), a Reduced Instruction Set Computing (RISC) processor, an Application-Specific Integrated Circuit (ASIC) processor, a Complex Instruction Set Computing (CISC) processor, a microcontroller, a central processing unit (CPU), and/or other control circuits. 
     The memory  204  may include suitable logic, circuitry, interfaces, and/or code that may be configured to store the one or more instructions to be executed by the circuitry  202 . The memory  204  may be configured to store a plurality of images that may include information about the light emitted by the lighting device  106 . In some embodiments, the memory  204  may be configured to store a set of parameters (such as intrinsic parameters) associated with the plurality of imaging devices  104 . The memory  204  may further store the plurality of rotation values and the plurality of translation values of each imaging device of the plurality of imaging devices  104 . Examples of implementation of the memory  204  may 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), a Solid-State Drive (SSD), a CPU cache, and/or a Secure Digital (SD) card. 
     The I/O device  206  may include suitable logic, circuitry, and interfaces that may be configured to receive an input and provide an output based on the received input. For example, the I/O device  206  may receive an input from a user to initiate the spatial synchronization of the plurality of imaging devices  104  (or the captured images). The I/O device  206  which may include various input and output devices, that may be configured to communicate with the circuitry  202 . Examples of the I/O device  206  may include, but are not limited to, a touch screen, a keyboard, a mouse, a joystick, a microphone, a display device, and a speaker. 
     The DC control circuit  208  may include suitable logic, circuitry, and interfaces that may be configured to control drive of the lighting device  106 . The DC control circuit  208  may receive the one or more control signal from the circuitry  202 . The DC control circuit  208  may activate or deactivate the grid of lights  108  and the edge light  110  of the lighting device  106  based on the received one or more control signals. Based on the activation or deactivation of the lighting device  106 , the lighting device  106  may emit the light. The DC control circuit  208  may further control a transformation (such as a rotation and a translation) of the lighting device  106  towards each imaging device. The DC control circuit  208  may further control the drive of the plurality of imaging devices  104  to initiate capture of the plurality of images that may include the information about the emitted light. In some embodiments, the DC control circuit  208  may be further configured to control the transformation (such as the rotation and the translation) of each imaging device of the plurality of imaging devices  104  towards the lighting device  106 . In an exemplary embodiment, the DC control circuit  208  may be a bipolar junction transistor (BJT) based control circuit or a metal oxide semiconductor field effect transistor (MOSFET) based control circuit which may be used to drive the lighting device  106  or the plurality of imaging devices  104 . In some embodiments, the DC control circuit  208  may be a part of the circuitry  202 . Although in  FIG.  2   , the DC control circuit  208  is shown separated from the circuitry  202 , the disclosure is not so limited. Accordingly, in some embodiments, the DC control circuit  208  may be integrated in the circuitry  202 , without deviation from scope of the disclosure. In some embodiments, the DC control circuit  208  may be integrated in the lighting device  106  and may receive an activation signal or a deactivation signal (such as the control signal) from the circuitry  202 , via the communication network  114 , to activate of deactivate the grid of lights  108  and the edge light  110  of the lighting device  106 . 
     The network interface  210  may comprise suitable logic, circuitry, and/or interfaces that may be configured to facilitate communication between the electronic device  102 , the plurality of imaging devices  104 , and the lighting device  106 , via the communication network  114 . The network interface  210  may be implemented by use of various known technologies to support wired or wireless communication of the electronic device  102  with the communication network  114 . 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 circuitry. The network interface  210  may be configured to communicate via wireless communication with networks, such as the Internet, an Intranet or a wireless network, such as a cellular telephone network, a wireless local area network (LAN), and a metropolitan area network (MAN). The wireless communication may be configured to use one or more of a plurality of communication standards, protocols and technologies, such as Global System for Mobile Communications (GSM), Enhanced Data GSM Environment (EDGE), wideband code division multiple access (W-CDMA), Long Term Evolution (LTE), 5G communication, code division multiple access (CDMA), time division multiple access (TDMA), Bluetooth, Wireless Fidelity (Wi-Fi) (such as IEEE 802.11a, IEEE 802.11b, IEEE 802.11g or IEEE 802.11n), voice over Internet Protocol (VoIP), light fidelity (Li-Fi), Worldwide Interoperability for Microwave Access (Wi-MAX), a protocol for email, instant messaging, and a Short Message Service (SMS). 
     A person of ordinary skill in the art will understand that the electronic device  102  in  FIG.  2    may also include other suitable components or systems, in addition to the components or systems which are illustrated herein to describe and explain the function and operation of the present disclosure. A detailed description for the other components or systems of the electronic device  102  has been omitted from the disclosure for the sake of brevity. The operations of the circuitry  202  are further described, for example, in  FIGS.  3 ,  4 A,  4 B and  4 C . 
       FIG.  3    is a diagram that illustrates an exemplary synchronization signal, in accordance with an embodiment of the disclosure.  FIG.  3    is explained in conjunction with elements from  FIGS.  1  and  2   . With reference to  FIG.  3   , there is shown an exemplary synchronization signal  300 . The synchronization signal  300  may include a preamble pulse  302  and a sequence of alternating ON/OFF pulses  304 . The sequence of alternating ON/OFF pulses  304  may include a first OFF pulse  304 A, a first ON pulse  304 B, a second OFF pulse  304 C, a second ON pulse  304 D, . . . , and an Nth ON pulse  304 N. 
     The circuitry  202  may be configured to generate the synchronization signal  300  as the one or more control signals, for estimation of the first rotation value and the first translation value of the plurality of rotation values and the plurality of translation values. In some embodiments, the synchronization signal  300  may be a random sequence of alternate ON/OFF pulses. In accordance with an embodiment, the synchronization signal  300  may be based on a set of parameters associated with each imaging device of the plurality of imaging devices  104 . 
     The circuitry  202  may be configured to determine the set of parameters associated with each imaging device of the plurality of imaging devices  104 . The set of parameters may include at least the frame rate (in frames captured per second) of each imaging device. The set of parameters associated with each imaging device may further include, but not limited to, exposure information, shutter speed information, aperture information, sensitivity parameter, white balance information, focus information, and/or zooming information associated with each imaging device. In an example, a white balance of each imaging device may be OFF. In an embodiment, the focus information and the zooming information may be same and constant for each imaging device of the plurality of imaging devices  104 . In some embodiments, the circuitry  202  may receive the set of parameters from respective imaging device of the plurality of imaging devices  104 . In another embodiment, the set of parameters for each imaging device may be stored in the memory  204 , and the circuitry  202  may further retrieve the set of parameters for each imaging device from the memory  204 . 
     The circuitry  202  may be configured to generate the synchronization signal  300  that may include the preamble pulse  302  of a first time duration (such as a duration “T1”) and the sequence of alternating ON and OFF pulses  304 . Each pulse of the sequence of alternating ON and OFF pulses  304  may be of a second time duration (such as a duration “D”, as shown in  FIG.  3   ). In such a case, each pulse of the sequence of alternating ON and OFF pulses  304  may be of the same second time duration. 
     The first time duration may be based on the frame rate of each imaging device. The first time duration may be set such that the first time duration may be equal to or more than a time duration of one or more frames of the first plurality of images associated with or captured by the plurality of imaging devices  104 . In other words, the first time duration may be set based on the total time duration (i.e. frame duration) of one or more frames captured by each of the plurality of imaging devices  104 . For example, the frame rate of the first imaging device  104 A may be 30 fps, and the frame rate of the second imaging device  1048  may be 35 fps. In such a case, the first plurality of images captured by the first imaging device  104 A may have 30 frames within a time period of “1” second and the first plurality of images captured by the second imaging device  1048  may have 35 frames within the time period of “1” second. Thus, the first time duration (“T1) may be a sum of the time duration of at least one frame (i.e. 33.33 milliseconds) captured by the first imaging device  104 A and the time duration of at least one frame (i.e. 28.6 milliseconds) captured by the second imaging device  1048 . The circuitry  202  may set the first time duration (“T1″) in few seconds, for example, 1-10 seconds. Thus, the preamble pulse  302  may be a long duration pulse. 
     The second time duration of each pulse of the sequence of alternating ON and OFF pulses  304  may be based on one or more parameters of the determined (or retrieved) set of parameters associated with each imaging device. The circuitry  202  may determine the second time duration, such as to achieve sub-frame timing accuracy. The second time duration may be based on equation (1) as follows: 
         D=n   i τ i   +p   i   (1)
 
     where D is the second time duration, τ i  is a time period of each frame of the first plurality of images and “i” represent an imaging device (such as the first imaging device  104 A). 
       Further, τ i   =p   i   ×q   i   (2)
 
     where q i  is a first positive integer value, n i  is a second positive integer value corresponding to the imaging device (such as the first imaging device  104 A), and p i  is an integer corresponding to a resolution of a subframe accuracy in milliseconds (msec) associated with the imaging device (such as the first imaging device  104 A). 
     In accordance with an embodiment, the set of parameters may include the first positive integer value and the second positive integer value corresponding to each imaging device of the plurality of imaging devices  104 . The circuitry  202  may be further configured to determine the first positive integer value and the second positive integer value based on the corresponding frame rate of each imaging device of the plurality of imaging devices  104 . 
     In an exemplary scenario, the frame rate of the first imaging device  104 A may be f i  fps. Thus, the time period τ i  of each frame of the first plurality of images may be 1000/f i  milliseconds. Based on the frame rate of the first imaging device  104 A, the circuitry  202  may determine the time period τ i  for the first imaging device  104 A. The circuitry  202  may further determine the integer p i , based on the resolution of the first imaging device  104 A and further determine the first positive integer value q i  utilizing equation 2. 
     Furthermore, the circuitry  202  may determine the second positive integer value n i , based on a number of frames of the first plurality of images that may include the OFF pulse pattern of the sequence of alternating ON and OFF pulses  304  or the ON pulse pattern of the sequence of alternating ON and OFF pulses  304 . In an embodiment, the n i  indicates the number of frames of the first plurality of images (i.e. captured by a particular imaging device) that may be included or counted in the second time duration (“D). For example, in case the second time duration (“D”) is of 2000 msec and τ i  is 480 msec, then n i  may be four, indicating that the four number of image frames may be included in the second time duration (“D”). 
     The circuitry  202  may be determine the second time duration (D) of each pulse of the sequence of alternating ON and OFF pulses  304  based on the frame rate f i , the determined first positive integer value q i , and the determined second positive integer value n i  associated with each imaging device of the plurality of imaging devices  104  by utilization of equation 1. Each of the determined first positive integer value and the determined second positive integer value may correspond to the set of parameters. For example, in case the second time duration (“D”) is 2000 msec and the frame timing (τ i ) of images captured by the first imaging device  104 A is 480 msec, then n i  may be “4”, p i  may be “80” and q i  may be “6” based on equations (1) and (2). Similarly, based on known or predefined values of τ i , n i , p i , and q i , the second time duration (“D”) may be determined based on use of equations (1) and (2). In some embodiments, the second time duration (D) may be determined utilizing a Chinese remainder theorem when the integer p i  and the time period τ i  may be natural numbers. In one or more embodiments, the second time duration (D) may be determined by utilizing a least common multiple (LCM) and a greatest common divisor (GCD) of fractions when the time period τ i  may be a rational number. 
     In accordance with an embodiment, a total duration (such as a duration “T2” shown in  FIG.  3   ) of the sequence of alternating ON and OFF pulses  304  of the synchronization signal  300  may be based on one or more parameters of the set of parameters. The set of parameters may further include a third positive integer value that may correspond to the one or more parameters of the set of parameters. The third positive integer value “m” may be determined based on a tradeoff between a synchronization time and accuracy of the synchronization of the images captured by the plurality of imaging devices  104 . In some embodiments, the higher a value of the third positive integer value “m”, the higher may be the accuracy of the synchronization and higher may be a time required for the synchronization of the images. For example, the higher the value of the third positive integer value “m”, the larger may be the total duration “T2” of the sequence of alternating ON and OFF pulses  304  of the synchronization signal  300 . In such a case, determination of the pattern of ON and OFF pulses corresponding to the sequence of alternating ON and OFF pulses  304  in the captured images may be more time consuming as additional pulses of the pattern of ON and OFF pulses may be determined for the synchronization. However, such a determination of the additional pulses of the pattern of ON and OFF pulses may also ensure more accuracy, as the determination of more number of pulses may ensure that the pattern of ON and OFF pulses may be correctly determined in the captured images, thereby, reducing a false positive rate. 
     In accordance with an embodiment, the circuitry  202  may be further configured to determine the total duration (“T2”) of the sequence of alternating ON and OFF pulses  304  of the synchronization signal  300  based on the determined first positive integer value and the third positive integer value. The total duration (“T2”) may be calculated based on equation (3), as follows: 
         T 2= m*N   (3)
 
     where “N”=max q i . In an embodiment, “N” may be determined based on a maximum value of the first positive integer value q i  corresponding to each imaging device of the plurality of imaging devices  104 . Thus, the circuitry  202  may utilize equations (1), (2), and (3) to generate the synchronization signal  300 . 
       FIGS.  4 A- 4 C  collectively illustrates a diagram for exemplary operations for spatial synchronization of videos, in accordance with an embodiment of the disclosure.  FIGS.  4 A- 4 C  are explained in conjunction with elements from  FIGS.  1 ,  2  and  3   . With reference to  FIGS.  4 A- 4 C , there is shown a diagram  400 . The diagram  400  may illustrate exemplary operations from  402  to  438 , as described herein. The exemplary operations illustrated in the block diagram  400  may start at  402  and may be performed by any computing system, apparatus, or device, such as by the electronic device  102  of  FIG.  1    or the circuitry  202  of  FIG.  2   . Although illustrated with discrete blocks, the exemplary operations associated with one or more blocks of the block diagram  400  may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on implementation of the exemplary operations. 
     At  402 , the circuitry  202  may be configured to determine the initial 3D coordinates of the lighting device  106 . The lighting device  106  may include the grid of lights  108  and the edge light  110  (as shown in  FIG.  1   ). In an embodiment, the initial 3D coordinates may be the Cartesian coordinates, that may include the x-coordinate, the y-coordinate and the z-coordinate of a position of the lighting device  106  in the space. The circuitry  202  may determine the initial 3D coordinates of the lighting device  106 , based on reference coordinates. The reference coordinates may be determined based on a position of the grid of lights  108  or the edge light  110  of the lighting device  106  with respect to the rotatable stand  112  (shown in  FIG.  1   ) of the lighting device  106 . 
     In an exemplary scenario, the grid of lights  108  and the edge light  110  of the lighting device  106  may be parallel to the rotatable stand  112 . In such a case, the reference coordinates of the lighting device  106  may be (x, y, z)=(0,0,0) and the 3D coordinates (0,0,0) may be the reference coordinates of the lighting device  106 . The lighting device  106  may be rotated and/or translated by rotation or translation, respectively, of a portion of the rotatable stand  112 , such as that portion is attached to the lighting device  106 . The lighting device  106  may be positioned at different angles by transformation (such as rotation or translation) of the rotatable stand  112  to transform the grid of lights  108  and the edge light  110  of the lighting device  106  towards each imaging device. The lighting device  106  may be transformed with respect to the plurality of imaging devices  104  which may be positioned in front or at certain angle of the lighting device  106 . For example, the grid of lights  108  may be rotated towards the first imaging device  104 A, to enable the first imaging device  104 A to capture the light emitted by the grid of lights  108  of the lighting device  106 . In another example, the edge light  110  may be rotated or translated towards the first imaging device  104 A, to enable the first imaging device  104 A to capture the light emitted by the edge light  110  of the lighting device  106 . The initial 3D coordinates may be determined, that may remain fixed with respect to the space. In an embodiment, the reference coordinates (0,0,0) may be the initial 3D coordinates of the lighting device  106 . The initial 3D coordinates of the lighting device  106  may be utilized to determine the rotation value and the translation value of each imaging device of the plurality of imaging devices  104 . 
     At  404 , the circuitry  202  may be configured to generate the synchronization signal  300 . The synchronization signal  300  may include the preamble pulse  302  and the sequence of alternating ON and OFF pulses  304 . In accordance with an embodiment, the generation of the synchronization signal  300  may be based on the set of parameters associated with each imaging device of the plurality of imaging devices  104 . The set of parameters may include at least the frame rate of each imaging device of the plurality of imaging devices  104 . Details of the generation of the synchronization signal  300  are further described, for example, in  FIG.  3   . 
     At  406 , the circuitry  202  may control the transformation (such as the rotation and/or the translation) of the lighting device  106  towards each imaging device of the plurality of imaging devices  104 . For example, each imaging device may be installed at different locations (i.e. close or at certain distance to the lighting device  106 ), to capture a scene from different viewpoints. The circuitry  202  may send a communication signal or a command to the lighting device  106 , to further rotate and translate the lighting device  106  such that the grid of lights  108  of the lighting device  106  may be in a field-of-view (FOV) of each imaging device. In other words, the circuitry  202  may control the transformation of the lighting device  106  in a manner that the lighting device  106  may face towards each imaging device of the plurality of imaging devices  104  one by one. For example, the circuitry  202  may control the transformation of the lighting device  106  towards the first imaging device  104 A (as shown in  FIG.  4 A ), then towards the second imaging device  1048 , and so on. 
     At  408 , the circuitry  202  may control an emission of light from the lighting device  106  based on the one or more control signals. In accordance with an embodiment, the circuitry  202  may control the emission of light from the lighting device  106  based on the generated synchronization signal  300 . The one or more control signals may include the synchronization signal  300 . The emitted light may include the pattern of alternating light pulses corresponding to the synchronization signal  300 . For example, the pattern of alternating light pulses may include a preamble pulse pattern corresponding to the preamble pulse  302 , an ON pattern corresponding to the ON pulses of the sequence of alternating ON and OFF pulses  304 , and an OFF pattern corresponding to the OFF pulses of the sequence of alternating ON and OFF pulses  304 . 
     In accordance with an embodiment, the circuitry  202  may activate the grid of lights  108  of the lighting device  106  to generate the ON pattern of the pattern of alternating light pulses included in the emitted light. The circuitry  202  may also deactivate the grid of lights  108  of the lighting device  106  to generate the OFF pattern of the pattern of alternating light pulses included in the emitted light. In a situation, where the grid of lights  108  is activated, the edge light  110  of the lighting device  106  may be deactivated. Thus, the light that may include the pattern of alternating light pulses may be emitted by the grid of lights  108  of the lighting device  106 . For example, the circuitry  202  may activate the grid of lights  108  for the second time duration “D”, to generate the ON pattern. Further, the circuitry  202  may deactivate the grid of lights  108  for the second time duration “D”, to generate the OFF pattern. Similarly, the circuitry  202  may activate the grid of lights  108  for the first time duration “T1” to generate the preamble pulse  302 . The circuitry  202  may activate the grid of lights  108  and deactivate the grid of lights  108  sequentially for the total duration “T2”, to generate the sequence of alternating ON and OFF pulses  304  of the synchronization signal  300 . 
     At  410 , the circuitry  202  may control each of the plurality of imaging devices  104  to capture a first plurality of images that may include information about the emitted light. For example, the first plurality of images may include the information about the emitted light (i.e. related to the synchronization signal  300 ) and a portion of the recorded scene by the plurality of imaging devices  104 . In accordance with an embodiment, the circuitry  202  may determine a first set of images from the first plurality of images that may include the information about the pattern of alternating light pulses included in the emitted light. The first set of images may include the information about the ON pattern of the pattern of alternating light pulses as well as the OFF pattern of the pattern of alternating light pulses. 
     In accordance with an embodiment, the circuitry  202  may be configured to control the plurality of imaging devices  104  to capture the first set of images based on a determination that the lighting device  106  may be in the field-of-view of a respective imaging device of the plurality of imaging devices  104 . For example, the circuitry  202  may control the transformation of the lighting device  106  towards the first imaging device  104 A (as described at  408 ), such that the lighting device  106  may be in the field-of-view of the first imaging device  104 A. In other words, the first imaging device  104 A may be able to see or capture the complete lighting device  106  when the grid of lights  108  are turned-on and the lighting device  106  are transformed towards the first imaging device  104 A. The circuitry  202  may further control the first imaging device  104 A to capture the first set of images of the first plurality of images. Similarly, the circuitry  202  may control the transformation of the lighting device  106  towards the second imaging device  1048  (at  408 ), such that the lighting device  106  may be in the field-of-view of the second imaging device  1048 . The circuitry  202  may further control the second imaging device  1048  to capture the first set of images of the first plurality of images. In such a manner, the circuitry  202  may capture the first set of images from each imaging device of the plurality of imaging devices  104 . 
     At  412 , the circuitry  202  may be configured to determine a center of each light of the grid of lights  108  in a first set of frames of the first set of images. The first set of frames may include the ON pattern of the pattern of alternating light pulses. For example, the circuitry  202  may determine the center of each light, such as a first light  412 A of the grid of lights  108  and the center of a second light  4128  of the grid of lights  108 . The circuitry  202  may further determine an end of the preamble pattern corresponding to the preamble pulse  302  based on a stored framing offset corresponding to each imaging device. The circuitry  202  may select the first set of frames, based on an identification of a frame that may include the stored framing offset. The pattern of alternating light pulses may be included in the frames (of the first plurality of images) that may come after the frame that includes the framing offset in a sequence. Thus, the circuitry  202  may select the first set of frames from the frames that may come after the frame that includes the framing offset. 
     In an exemplary scenario, each light of the grid of lights  108  may be a circular shaped light. The circuitry  202  may determine the center of each light of the grid of lights  108  of the lighting device  106  based on a light intensity in each frame of the first set of frames. For example, the emitted light at the center of each light of the grid of lights  108  may have a maximum light intensity as compared to surrounding portions of each light of the grid of lights  108 . The circuitry  202  may determine the light intensity in each pixel of each frame of the first set of frames to determine the center of each light of the grid of lights  108 . In an embodiment, the circuitry  202  may determine a set of pixels in each frame corresponding to the maximum light intensity as the center of each light of the grid of lights  108 . Thus, based on the determined light intensity, the circuitry  202  may determine the center for each light of the grid of lights  108 . 
     In accordance with an embodiment, the circuitry  202  may be configured to apply a set of post-processing operations on the first set of frames of the first set of images. The set of post-processing operations may include, for example, a filtering operation. The circuitry  202  may filter-out one or more frames of the first set of frames that may have the light intensity less than a threshold value. In some embodiments, the circuitry  202  may further determine the center of each light of the grid of lights  108  of the lighting device  106  in the post-processed first set of frames of the first set of images. In some embodiments, the set of post-processing operations may further include, but is not limited to, a pixel-level filtering operation for each of the first set of frames (such as including a noise removal operation, a contrast enhancement operation, and/or an edge smoothing operation). 
     In an exemplary scenario, a frame of the first set of frames may include a first portion of the ON pattern and a second portion of the OFF pattern of the pattern of alternating light pulses. The circuitry  202  may determine that the first portion of the ON pattern may be less than the second portion of the OFF pattern of the pattern of alternating light pulses, based on the determined light intensity in the frame. Such frame may be invaluable in the determination of the center of each light of the grid of lights  108 . Thus, based on the determination, the circuitry  202  may apply the filtering operation to eliminate such frame from the first set of frames. The circuitry  202  may determine the center of each light of the grid of lights  108  in the post-processed first set of frames. 
     In accordance with an embodiment, the circuitry  202  may be configured to apply a neural network model (not shown) on the first set of frames of the first set of images to determine a first frame. The circuitry  202  may further determine the center of each light of the grid of lights  108  of the lighting device  106  in the determined first frame of the first set of frames. 
     The neural network model may be a computational network or a system of artificial neurons, arranged in a plurality of layers, as nodes. The plurality of layers of the neural network model may include an input layer, one or more hidden layers, and an output layer. Each layer of the plurality of layers may include one or more nodes (or artificial neurons, represented by circles, for example). Outputs of all nodes in the input layer may be coupled to at least one node of hidden layer(s). Similarly, inputs of each hidden layer may be coupled to outputs of at least one node in other layers of the neural network. Outputs of each hidden layer may be coupled to inputs of at least one node in other layers of the neural network. Node(s) in the final layer may receive inputs from at least one hidden layer to output a result. The number of layers and the number of nodes in each layer may be determined from hyper-parameters of the neural network model. Such hyper-parameters may be set before, while training, or after training of the neural network model on a training dataset. 
     Each node of the neural network model may correspond to a mathematical function (e.g., a sigmoid function or a rectified linear unit) with a set of parameters, tunable during training of the network. The set of parameters may include, for example, a weight parameter, a regularization parameter, and the like. Each node may use the mathematical function to compute an output based on one or more inputs from nodes in other layer(s) (e.g., previous layer(s)) of the neural network model. All or some of the nodes of the neural network model may correspond to same or a different same mathematical function. In training of the neural network model, one or more parameters of each node of the neural network model may be updated based on whether an output of the final layer for a given input (from the training dataset) matches a correct result based on a loss function for the neural network model. The above process may be repeated for same or a different input till a minima of loss function may be achieved, and a training error may be minimized. Several methods for training are known in art, for example, gradient descent, stochastic gradient descent, batch gradient descent, gradient boost, meta-heuristics, and the like. 
     The neural network model may include electronic data, which may be implemented as, for example, a software component of an application executable on the electronic device  102 . The neural network model may rely on libraries, external scripts, or other logic/instructions for execution by a processing device, such as the circuitry  202 . The neural network model may include code and routines configured to enable a computing device, such as the circuitry  202  to perform one or more operations for determination of the first frame of the first set of frames. Additionally or alternatively, the neural network model may be implemented using hardware including a processor, a microprocessor (e.g., to perform or control performance of one or more operations), a field-programmable gate array (FPGA), or an application-specific integrated circuit (ASIC). Alternatively, in some embodiments, the neural network model may be implemented using a combination of hardware and software. Examples of the neural network model may include, but are not limited to, a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a CNN-recurrent neural network (CNN-RNN), an artificial neural network (ANN), a generative adversarial network (GAN), a Long Short Term Memory (LSTM) network based RNN, CNN+ANN, LSTM+ANN, a gated recurrent unit (GRU)-based RNN, a fully connected neural network, a Connectionist Temporal Classification (CTC) based RNN, a deep Bayesian neural network, and/or a combination of such networks. In some embodiments, the learning engine may include numerical computation techniques using data flow graphs. In certain embodiments, the neural network model may be based on a hybrid architecture of multiple Deep Neural Networks (DNNs). 
     The circuitry  202  may train the neural network model to determine the first frame based on input of the first set of frames of the first set of images. In some embodiments, the circuitry  202  may apply an average function to determine the first frame of the first set of frames to determine the center of each light of the grid of lights  108  of the lighting device  106 . 
     With respect to  FIG.  4 B , at  414 , the circuitry  202  may be configured to activate the edge light  110  of the lighting device  106 . The edge light  110  may be activated to emit light, such as a continuous light pulse. In some embodiments, the circuitry  202  may deactivate the grid of lights  108  of the lighting device  106  at the time of activation of the edge light  110 . The edge light  110  may be activated based on an electrical signal (such as a control signal) transmitted from the circuitry  202  of the electronic device  102 . In an embodiment, the circuitry  202  may be configured to control a light intensity of the edge light  110  at which the edge light  110  may emit the continuous light pulse. 
     At  416 , the circuitry  202  may further control the transformation of the lighting device  106  towards each imaging device of the plurality of imaging devices  104 . The transformation may include at least one of the rotation or the translation of the lighting device  106 . The circuitry  202  may control the transformation of the lighting device  106  such that the edge light  110  of the lighting device  106  may be in the field-of-view of the plurality of imaging devices  104 . In an exemplary scenario, the circuitry  202  may control the rotation and/or translation of the lighting device  106 , such that the edge light  110  may be in the field-of-view of the first imaging device  104 A. Similarly, the circuitry  202  may further control the rotation and/or translation of the lighting device  106 , such that the edge light  110  may be in the field-of-view of the second imaging device  104 B, and so on. Thus, the circuitry  202  may control the rotation and/or translation of the lighting device  106  to enable the plurality of imaging devices  104  to capture the continuous light pulse emitted from the edge light  110 . 
     At  418 , the circuitry  202  may control the plurality of imaging devices  104  to capture light emitted by the edge light  110 , based on the transformation of the lighting device  106 . The circuitry  202  may activate the plurality of imaging devices  104  to capture the light emitted by the edge light  110 . In some embodiments, the plurality of imaging devices  104  may be manually activated to capture the light emitted by the edge light  110 . 
     At  420 , the circuitry  202  may be configured to receive, from the plurality of imaging devices  104 , a second plurality of images captured by the plurality of imaging devices  104 . The received second plurality of images may include information about the light emitted by the edge light  110 . In some embodiments, the second plurality of images may include one or more images that may exclude the information about the light emitted by the edge light  110 . For example, the first imaging device  104 A may be activated for a period of “5” seconds, and the edge light  110  may emit the light for a period of “3” seconds. In such a case, the second plurality of images may include one or more images captured for an additional period of “2” seconds, that may exclude the information about the light emitted by the edge light  110 . The circuitry  202  may utilize a sharp contrast in the light intensity (such as brightness) in the second plurality of images to identify such one or more images that may exclude the information about the light emitted by the edge light  110 . The circuitry  202  may further exclude the identified one or more images that may exclude the information about the light emitted by the edge light  110 . In such a manner, the circuitry  202  may determine the second plurality of images that may include the information about the light emitted by the edge light  110 . 
     At  422 , the circuitry  202  may be configured to estimate a slope of the information about the light emitted by the edge light  110  in the second plurality of images captured by the plurality of imaging devices  104 . For example, the information about the light emitted by the edge light  110  may be different in each of the second plurality of images captured by respective imaging device. For example, the circuitry  202  may control the transformation of the lighting device  106 , such that the lighting device  106  may be at a first angle with respect to the first imaging device  104 A. In such a case, the information about the light emitted by the edge light  110  in the second plurality of images (i.e. captured by the first imaging device  104 A) may correspond to be at the first angle. Similarly, the information about the light emitted by the edge light  110  in the second plurality of images (i.e. captured by the second imaging device  104 B) may correspond to be at another angle different than the first angle (i.e. corresponding to the first imaging device  104 A). The circuitry  202  may determine the slope of the information about the light emitted by the edge light  110 , based on a shape of the light (i.e. emitted by the edge light  110 ) captured in the second plurality of images. 
     At  424 , the circuitry  202  may be configured to determine a set of grid lines  424 A passing through the determined center of each light of the grid of lights  108  of the lighting device  106  in the first set of frames, based on the estimated slope of the information about the light emitted by the edge light  110  in the second plurality of images. The set of grid lines  424 A may correspond to a set of vertical lines and a set of horizontal lines passing through the center of each light of the grid of lights  108 . 
     In accordance with an embodiment, the circuitry  202  may be configured to determine the set of grid lines  424 A passing through the determined center of each light of the grid of lights  108  in the first set of frames, based on a mathematical optimization function. For example, the mathematical optimization function may be based on an argmin function. The mathematical optimization function may be defined using equation (4) as follows: 
     
       
         
           
             
               
                 
                   
                     L 
                     * 
                   
                   = 
                   
                     
                       
                         
                           arg 
                           ⁢ 
                              
                           min 
                         
                         L 
                       
                       ⁢ 
                          
                       
                         
                           E 
                           pass 
                         
                         ( 
                         
                           
                             ∀ 
                             
                               l 
                               ∈ 
                               L 
                             
                           
                           , 
                           
                             I 
                             
                               p 
                               ∈ 
                               l 
                             
                           
                         
                         ) 
                       
                     
                     + 
                     
                       
                         E 
                         slope 
                       
                       ( 
                       
                         
                           ∀ 
                           
                             l 
                             ∈ 
                             L 
                           
                         
                         , 
                         
                           
                             l 
                             ′ 
                           
                           ∈ 
                           
                             N 
                             ⁡ 
                             ( 
                             l 
                             ) 
                           
                         
                       
                       ) 
                     
                   
                 
               
               
                 
                   ( 
                   4 
                   ) 
                 
               
             
           
         
       
     
     where “L” may represent the set of grid lines  424 A, constrained by the estimated slope of the information about the light emitted by the edge light  110  in the second plurality of images. “I” may represent the information about the light of the grid of lights  108  in the first set of images. I p∈l  may represent the light intensity of a pixel passing through “l”. 
     In an embodiment, E pass (I p∈l ) may be a smaller quantity, if I p∈l  may be a bigger quantity. Further, N (I) may be neighboring lines of “l” in a same dimension of a pattern of the set of grid lines  424 A. Moreover, E slope  (l, l′) may be a smaller quantity if directions of “l” and “l′” may close in the second plurality of images. Based on the equation (4), the circuitry  202  may determine the set of grid lines  424 A. 
     In accordance with an embodiment, the circuitry  202  may determine the set of grid lines  424 A passing through the determined center of each light of the grid of lights  108  in the first set of frames based on the neural network model. For example, the neural network model may be the same neural network model used to determine the first frame of the first set of frames (i.e. described at  412 ). In some embodiments, the circuitry  202  may utilize a transform function, such as Hough transform function to determine the set of grid lines  424 A passing through the determined center of each light of the grid of lights  108  in the first set of frames. 
     With respect to  FIG.  4 C , at  426 , the circuitry  202  may be configured to determine one or more projected 2D positions of the center of each light in the first set of frames, based on an intersection of the determined set of grid lines  424 A. For example, the intersection of the determined set of grid lines  424 A may coincide with the center of each light in the first set of frames as shown, for example, in  FIG.  4 B ). Thus, the circuitry  202  may determine the one or more projected 2D positions, based on the intersection of the determined set of grid lines  424 A. 
     At  428 , the circuitry  202  may be configured to estimate a first rotation value of the plurality of rotation values and a first translation value of the plurality of translation values, for each imaging device, based on the initial 3D coordinates of the lighting device  106  and the determined center of each light of the grid of lights  108  in the first set of frames. In some embodiments, the circuitry  202  may estimate the first rotation value and the first translation value, of each imaging device, based on the initial 3D coordinates of the lighting device  106  and the determined one or more projected 2D positions of the center of each light. 
     In an exemplary scenario, the initial 3D coordinates of the lighting device  106  may be known. In such scenario, the circuitry  202  may determine the first rotation value and the first translation value corresponding to each imaging device. For example, the circuitry  202  may determine the first rotation value and the first translation value corresponding to the first imaging device  104 A. Similarly, the circuitry  202  may determine the first rotation value and the first translation value corresponding to the second imaging device  104 B, and the Nth imaging device  104 N. The first rotation value and the first translation value corresponding to each imaging device may be with respect to the common 3D coordinates (such as the initial 3D coordinates) of the lighting device  106 . 
     In accordance with an embodiment, the circuitry  202  may be further configured to estimate the first rotation value and the first translation value of the plurality of rotation values and the plurality of translation values, for each imaging device of the plurality of imaging devices  104 , based on a perspective-n-point (PnP) technique. The PnP technique may utilize the initial 3D coordinates of the lighting device  106  and the corresponding one or more projected 2D positions of the center of each light in the first set of frames to estimate the first rotation value and the first translation value. Each imaging device of the plurality of imaging devices  104  may achieve 6 degrees-of-freedom (DOF). Thus, the PnP technique may be utilized to determine the first rotation value that may include values corresponding to roll, pitch, and yaw of each imaging device, and the first translation value. 
     At  430 , the circuitry  202  may control the emission of light from the lighting device  106  based on a control signal (i.e. included in the one or more control signals). The emitted light may include a continuous light pulse corresponding to the control signal. The control signals may enable the lighting device  106  to emit the continuous light pulse for a specific time period. 
     In accordance with an embodiment, for the control of the emission of the light from the lighting device  106  based on the control signal, the circuitry  202  may activate the grid of lights  108  of the lighting device  106  to emit the light. The circuitry  202  may further deactivate the edge light  110  of the lighting device  106 , at the time of activation of the grid of lights  108 . For example, the circuitry  202  may activate the grid of lights  108  of the lighting device  106  for the specific time period to emit the continuous light pulse. The grid of lights  108  may be activated when the grid of lights  108  of the lighting device  106  may be in the field-of-view of the respective imaging device of the plurality of imaging devices  104 . 
     At  432 , the circuitry  202  may control the transformation of each imaging device of the plurality of imaging devices  104  for a first time period. Each imaging device may further capture a second set of images of the first plurality of images. For example, the circuitry  202  may control the transformation (i.e. rotation and/or translation) of each imaging device such that each imaging device may be able to capture the second set of images, when the grid of lights  108  of the lighting device  106  may be activated and in the field-of-view of the imaging device. In an exemplary scenario, the circuitry  202  may activate the grid of lights  108  to emit the continuous light pulse. The circuitry  202  may control the rotation and/or the translation of the first imaging device  104 A towards the activated grid of lights  108 . Further, the second set of images may be captured by the first imaging device  104 A, based on the determination that the lighting device  106  may be in the field-of-view of the first imaging device  104 A of the plurality of imaging devices  104 . In a similar manner, the second set of images may be captured by each imaging device of the plurality of imaging devices  104  based on the determination that the lighting device  106  may be in the field-of-view of respective imaging device of the plurality of imaging devices  104 . 
     At  434 , a center of each light, of the grid of lights  108  of the lighting device  106 , may be determined in the second set of images. The circuitry  202  may determine the center of each light, of the grid of lights  108 , based on the light intensity in each image of the second set of images. For example, the circuitry  202  may determine the center of each light, of the grid of lights  108  in the second set of images, in a similar manner as the center of each light of the grid of lights  108  may be determined in the first set of frames of the first set of images (i.e. described, for example, at  412 ). 
     In some embodiments, the circuitry  202  may determine a set of features associated with each image of the second set of images. The set of features may be utilized to determine a correspondence between objects in the second set of images for calibration (or spatial synchronization) of the plurality of imaging devices  104 . For example, the set of features may be determined based on a scale-invariant feature transform (SIFT) technique. In one or more embodiments, the set of features may be determined based on an oriented FAST and rotated BRIEF (ORB) technique applied on the second set of images. 
     At  436 , the circuitry  202  may be further configured to estimate the plurality of rotation values and the plurality of translation values of each imaging device, based on the determined 3D coordinates of the lighting device  106  and the information about the emitted light included in the first plurality of images. In accordance with an embodiment, the circuitry  202  may estimate a second rotation value and a second translation value of the plurality of rotation values and the plurality of translation values, for each imaging device of the plurality of imaging devices  104 , based on the determined 3D coordinates of the lighting device  106  and the determined center of each light of the grid of lights  108  of the lighting device in the second set of images. In some embodiments, the circuitry  202  may further utilize the set of features for estimation of the second rotation value and the second translation value. The plurality of rotation values and the plurality of translation values may include the estimated second rotation value and the second translation value for each imaging device of the plurality of imaging devices  104 . 
     For example, the circuitry  202  may determine the second rotation value and the second translation value corresponding to each imaging device. For example, the circuitry  202  may determine the second rotation value and the second translation value corresponding to the first imaging device  104 A. Similarly, the circuitry  202  may determine the second rotation value and the second translation value corresponding to the second imaging device  104 B, and the Nth imaging device  104 N. The second rotation value and the second translation value corresponding to each imaging device may be with respect to the common 3D coordinates (such as the initial 3D coordinates) of the lighting device  106 . In accordance with an embodiment, the circuitry  202  may be further configured to estimate the second rotation value and the second translation value of the plurality of rotation values and the plurality of translation values, for each imaging device of the plurality of imaging devices  104 , based on the PnP technique (i.e. described at  428 ). 
     At  438 , the circuitry  202  may be further configured to apply the simultaneous localization and mapping (SLAM) process for each imaging device, based on the plurality of rotation values and the plurality of translation values (such as including the estimated second rotation value and the second translation value), for the spatial synchronization (or calibration) of the plurality of imaging devices  104 . The circuitry  202  may input the determined set of features in a 3D map corresponding to the SLAM process, to determine a spatial scaling factor for each imaging device. Based on the determined set of features input in the 3D map and the estimated second rotation value and the second translation value, the circuitry  202  may apply the SLAM process for each imaging device of the plurality of imaging devices  104 . Thus, the circuitry  202  of the disclosed electronic device  102  may allow accurate calibration (or spatial synchronization) of each imaging device by application of the SLAM process on the estimated second rotation value and the second translation value for each imaging device or on the plurality of rotation values and the plurality of translation values. Therefore, the plurality of imaging devices  104  may be automatically calibrated (or spatially synchronized) accurately, by utilization of the single lighting device  106 . Thus, the disclosed electronic device  102  may enable calibration of the plurality of imaging devices  104  by use of the single lighting device (such as the lighting device  106 ). The light emitted by the lighting device  106  may be utilized to spatially synchronize the plurality of imaging devices  104  (as described, for example, at  402 - 438 ), thereby, providing an easy-to-implement setup that may guarantee accuracy in the calibration. Moreover, in the conventional systems, measurement targets, such as checkerboard patterned-boards and identifiable markers may be utilized for the spatial synchronization of the plurality of imaging devices, use of which may be time-consuming and inefficient to achieve the calibration. In contrast, the disclosed electronic device  102  may eliminate a usage of such measurement targets to calibrate the plurality of imaging devices, and may further calibrate the plurality of imaging devices  104  based on the determination of the extrinsic parameters (i.e. rotation and translation) of each imaging device based on the information included in the light emitted by the lighting device  106 . Therefore, the disclosed electronic device  102  may provide a time-effective and efficient spatial synchronization of the plurality of imaging devices  104  and of the images/videos captured by the plurality of imaging devices  104 . 
     Although the diagram  400  is illustrated as discrete operations, such as  402 ,  404 ,  406 ,  408 ,  410 ,  412 ,  414 ,  416 ,  418 ,  420 ,  422 ,  424 ,  426 ,  428 ,  430 ,  432 ,  434 ,  436 , and  438 , the disclosure is not so limited. Accordingly, in certain embodiments, such discrete operations may be further divided into additional operations, combined into fewer operations, or eliminated, depending on the particular implementation without detracting from the essence of the disclosed embodiments. 
       FIG.  5    is a flowchart that illustrates an exemplary method for spatial synchronization of videos, in accordance with an embodiment of the disclosure.  FIG.  5    is explained in conjunction with elements from  FIGS.  1 ,  2 ,  3 ,  4 A,  4 B, and  4 C . With reference to  FIG.  5   , there is shown a flowchart  500 . The operations of the flowchart  500  may be executed by a computing system, such as the electronic device  102  or the circuitry  202 . The operations may start at  502  and proceed to  504 . 
     At  504 , the initial 3D coordinates of the lighting device  106  may be determined. The lighting device  106  may include the grid of lights  108  and the edge light  110 . In accordance with an embodiment, the circuitry  202  may be configured to determine the initial 3D coordinates of the lighting device  106  as described, for example, in  FIG.  4 A  (at  402 ). 
     At  506 , the emission of light from the lighting device  106  may be controlled based on the one or more control signals. The emitted light may include at least one of the pattern of alternating light pulses or the continuous light pulse. In accordance with an embodiment, the circuitry  202  may be configured to control the emission of light from the lighting device  106  based on the one or more control signals (i.e. including the synchronization signal  300 ) as described, for example, in  FIG.  4 A  (at  408 ). 
     At  508 , the plurality of imaging devices  104  may be controlled to capture the first plurality of images that may include the information about the emitted light. In accordance with an embodiment, the circuitry  202  may be configured to control the plurality of imaging devices  104  to capture the first plurality of images that may include the information about the emitted light as described, for example, in  FIG.  4 A  (at  410 ). 
     At  510 , the plurality of rotation values and the plurality of translation values of each imaging device may be estimated, based on the determined 3D coordinates of the lighting device  106  and the information about the emitted light included in the first plurality of images. In accordance with an embodiment, the circuitry  202  may be configured to estimate the plurality of rotation values and the plurality of translation values of each imaging device, based on the determined 3D coordinates of the lighting device  106  and the information about the emitted light included in the first plurality of images as described, for example, in  FIGS.  4 A- 4 C  (at least at  428  and  436 ). 
     At  512 , the simultaneous localization and mapping (SLAM) process may be applied for each imaging device, based on the plurality of rotation values and the plurality of translation values, for spatial synchronization of the plurality of imaging devices  104 . In accordance with an embodiment, the circuitry  202  may be configured to apply the SLAM process for each imaging device, based on the plurality of rotation values and the plurality of translation values, for the spatial synchronization of the plurality of imaging devices  104  as described, for example, in  FIG.  4 C  (at  438 ). 
     Although the flowchart  500  is illustrated as discrete operations, such as  504 ,  506 ,  508 ,  510 , and  512 , the disclosure is not so limited. Accordingly, in certain embodiments, such discrete operations may be further divided into additional operations, combined into fewer operations, or eliminated, depending on the particular implementation without detracting from the essence of the disclosed embodiments. 
     Various embodiments of the disclosure may provide a non-transitory computer-readable medium having stored thereon, computer-executable instructions that when executed by an electronic device (the electronic device  102 ) causes the electronic device  102  to execute operations. The operations may include determination of initial three-dimensional (3D) coordinates of a lighting device (such as the lighting device  106 ). The lighting device  106  may include a grid of lights (such as the grid of lights  108 ) and an edge light (such as the edge light  110 ). The operations may further include control of an emission of light from the lighting device  106  based on one or more control signals. The emitted light may include at least one of the pattern of alternating light pulses or the continuous light pulse. The operations may further include control of a plurality of imaging devices (such as the plurality of imaging devices  104 ) to capture a first plurality of images that may include information about the emitted light. The operations may further include estimation of a plurality of rotation values and a plurality of translation values of each imaging device, based on the determined 3D coordinates of the lighting device  106  and the information about the emitted light included in the first plurality of images. The operations may further include application of a simultaneous localization and mapping (SLAM) process for each imaging device, based on the plurality of rotation values and the plurality of translation values, for spatial synchronization of the plurality of imaging devices  104 . 
     Exemplary aspects of the disclosure may include an electronic device (such as the electronic device  102 ). The electronic device  102  may include circuitry (such as the circuitry  202 ) that may be configured to determine initial three-dimensional (3D) coordinates of a lighting device (such as the lighting device  106 ). The lighting device  106  may include a grid of lights (such as the grid of lights  108 ) and an edge light (such as the edge light  110 ). The circuitry  202  may be further configured to control an emission of light from the lighting device  106  based on one or more control signals. The emitted light may include at least one of the pattern of alternating light pulses or the continuous light pulse. The circuitry  202  may be further configured to control a plurality of imaging devices (such as the plurality of imaging devices  104 ) to capture a first plurality of images that may include information about the emitted light. The circuitry  202  may be further configured to estimate a plurality of rotation values and a plurality of translation values of each imaging device, based on the determined 3D coordinates of the lighting device  106  and the information about the emitted light included in the first plurality of images. The circuitry  202  may be further configured to apply a simultaneous localization and mapping (SLAM) process for each imaging device, based on the plurality of rotation values and the plurality of translation values, for spatial synchronization of the plurality of imaging devices  104 . 
     In accordance with an embodiment, the circuitry  202  may be further configured to generate a synchronization signal (such as the synchronization signal  300 ) that may include a preamble pulse (such as the preamble pulse  302 ) and sequence of alternating ON and OFF pulses (such as the sequence of alternating ON and OFF pulses  304 ). The one or more control signals may include the synchronization signal  300 . The circuitry  202  may control the emission of light from the lighting device  106  based on the generated synchronization signal  300  that may include the pattern of alternating light pulses corresponding to the generated synchronization signal  300 . In accordance with an embodiment, the circuitry  202  may be further configured to generate the synchronization signal  300  based on the set of parameters associated with each imaging device of the plurality of imaging devices  104 . The set of parameters may include at least the frame rate of each imaging device of the plurality of imaging devices  104 . 
     In accordance with an embodiment, for the control of the emission of the light from the lighting device  106  based on the generated synchronization signal  300 , the circuitry  202  may be further configured to activate the grid of lights  108  of the lighting device  106  to generate the ON pattern of the pattern of alternating light pulses included in the emitted light. The circuitry  202  may further deactivate the grid of lights  108  of the lighting device  106  to generate the OFF pattern of the pattern of alternating light pulses included in the emitted light. The circuitry  202  may deactivate the edge light  110  of the lighting device  106 . 
     In accordance with an embodiment, the circuitry  202  may be further configured to determine a first set of images of the first plurality of images that may include information about the pattern of alternating light pulses included in the emitted light. The circuitry  202  may determine the center of each light of the grid of lights  108  of the lighting device  106  in a first set of frames of the first set of images. The first set of frames may include the ON pattern of the pattern of alternating light pulses. The circuitry  202  may further estimate a first rotation value and a first translation value of the plurality of rotation values and the plurality of translation values, for each imaging device, based on the 3D coordinates of the lighting device  106  and the determined center of each light of the grid of lights  108  in the first set of frames. 
     In accordance with an embodiment, the circuitry  202  may be further configured to control the plurality of imaging devices  104  to capture the first set of images based on the determination that the lighting device  106  may be in the field-of-view of the respective imaging device of the plurality of imaging devices  104 . In accordance with an embodiment, the circuitry  202  may be further configured to apply the set of post-processing operations on the first set of frames of the first plurality of images. The circuitry  202  may determine the center of each light of the grid of lights  108  of the lighting device  106  in the post-processed first set of frames of the first plurality of images. 
     In accordance with an embodiment, the circuitry  202  may be further configured to apply the neural network model on the first set of frames of the first plurality of images to determine a first frame. The first frame may include the information about the pattern of alternating light pulses. The circuitry  202  may further determine the center of each light of the grid of lights  108  of the lighting device  106  in the determined first frame of the first set of frames. 
     In accordance with an embodiment, the circuitry  202  may be further configured to control the lighting device  106  to activate the edge light  110  of the lighting device  106 . The circuitry  202  may control the transformation of the lighting device  106  towards each imaging device of the plurality of imaging devices  104 . The transformation may include at least one of the rotation or the translation of the lighting device  106 . The circuitry  202  may control the plurality of imaging devices  104  to capture light emitted by the edge light  110 , based on the transformation of the lighting device  106 . The circuitry  202  may receive, from the plurality of imaging devices  104 , a second plurality of images captured by the plurality of imaging devices  104 . The received second plurality of images may include information about the light emitted by the edge light  110 . The circuitry  202  may estimate a slope of the information about the light emitted by the edge light  110  in the second plurality of images captured by the plurality of imaging devices  104 . 
     In accordance with an embodiment, the circuitry  202  may be further configured to determine a set of grid lines (such as the set of grid lines  424 A) passing through the determined center of each light of the grid of lights  108  of the lighting device  106  in the first set of frames, based on the estimated slope of the information about the light emitted by the edge light in the second plurality of images. The circuitry  202  may further determine one or more projected 2D positions of the center of each light in the first set of frames, based on the intersection of the determined set of grid lines  424 A. The circuitry  202  may estimate the first rotation value and the first translation value of the plurality of rotation values and the plurality of translation values, of each imaging device, based on the 3D coordinates of the lighting device  106  and the determined one or more projected 2D positions of the center of each light. 
     In accordance with an embodiment, the circuitry  202  may be further configured to estimate the first rotation value and the first translation value of the plurality of rotation values and the plurality of translation values, for each imaging device of the plurality of imaging devices, based on a perspective-n-point (PnP) technique. In accordance with an embodiment, the circuitry  202  may be further configured to determine the set of grid lines  424 A passing through the determined center of each light of the grid of lights  108  in the first set of frames, based on the mathematical optimization function. In accordance with an embodiment, the circuitry  202  may be further configured to determine the set of grid lines  424 A passing through the determined center of each light of the grid of lights  108  in the first set of frames based on the neural network model. 
     In accordance with an embodiment, the circuitry  202  may be further configured to control the emission of the light from the lighting device  106  based on the control signal. The emitted light may include the continuous light pulse corresponding to the control signal. The one or more control signals may include the control signal. In accordance with an embodiment, the circuitry  202  may be further configured to, for the control of the emission of the light from the lighting device  106  based on the control signal, activate the grid of lights  108  of the lighting device  106  to emit the light. The circuitry  202  may further deactivate the edge light  110  of the lighting device  106 . 
     In accordance with an embodiment, the circuitry  202  may be further configured to control the transformation of each imaging device of the plurality of imaging devices  104  for a first time period. Each imaging device may capture a second set of images of the first plurality of images. The circuitry  202  may determine the center of each light, of the grid of lights  108  of the lighting device  106 , in the second set of images. The second set of images may include information about the emitted light that may include the continuous light pulse. The circuitry  202  may estimate a second rotation value and a second translation value of the estimated plurality of rotation values and the plurality of translation values, for each imaging device of the plurality of imaging devices  104 , based on the determined 3D coordinates of the lighting device  106  and the determined center of each light of the grid of lights  108  of the lighting device  106  in the second set of images. The circuitry  202  may further apply the SLAM process for each imaging device, based on the estimated second rotation value and the second translation value, for the spatial synchronization of the plurality of imaging devices  104 . In accordance with an embodiment, the circuitry  202  may be further configured to control each imaging device of the plurality of imaging devices  104  to capture the second set of images, based on the determination that the lighting device  106  may be in the field-of-view of the respective imaging device of the plurality of imaging devices  104 . 
     The present disclosure may be realized in hardware, or a combination of hardware and software. The present disclosure may be realized in a centralized fashion, in at least one computer system, or in a distributed fashion, where different elements may be spread across several interconnected computer systems. A computer system or other apparatus adapted to carry out the methods described herein may be suited. A combination of hardware and software may be a general-purpose computer system with a computer program that, when loaded and executed, may control the computer system such that it carries out the methods described herein. The present disclosure may be realized in hardware that comprises a portion of an integrated circuit that also performs other functions. 
     The present disclosure may also be embedded in a computer program product, which comprises all the features that enable the implementation of the methods described herein, and which when loaded in a computer system is able to carry out these methods. Computer program, in the present context, means any expression, in any language, code or notation, of a set of instructions intended to cause a system with information processing capability to perform a particular function either directly, or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form. 
     While the present disclosure is described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted without departure from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departure from its scope. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed, but that the present disclosure will include all embodiments that fall within the scope of the appended claims.