Patent Publication Number: US-2021185247-A1

Title: Using IR Sensor With Beam Splitter to Obtain Depth

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. § 119(e) of co-pending U.S. Provisional Patent Application No. 62/947,765, filed Dec. 13, 2019, entitled “Beam Splitter with IR Sensor.” The disclosure of the above-referenced application is incorporated herein by reference. 
    
    
     BACKGROUND 
     Field 
     The present disclosure relates to optical apparatus, and more specifically, to using an infra-red (IR) sensor with a beam splitter to obtain depth information. 
     Background 
     In video production, it is important to synchronize the data collected from the cameras and sensors. The collected data may be synchronized using the positions of the cameras and sensors. However, calibrating the cameras and sensors to control the positions can be difficult. 
     SUMMARY 
     The present disclosure provides for obtaining depth information using an IR sensor with a beam splitter. 
     In one implementation, a system is disclosed. The system includes: an IR light source to illuminate a subject with IR light; a beam splitter to receive a beam of visible light and IR light reflected by the subject, the beam splitter to split the beam of visible light and IR light into two identical beams, a first beam and a second beam; an IR sensor coupled to the beam splitter, the IR sensor to receive and process the first beam to pass the IR light and to block the visible light to generate an IR image, wherein the IR light source is coupled to the IR sensor such that a time of flight of the IR light illuminated by the IR light source and received by the IR sensor is used to calculate a distance of the subject from the beam splitter; and a visible light sensor coupled to the beam splitter, the visible light sensor to receive and process the second beam to pass the visible light and to block the IR light to generate a visible light image. 
     In one implementation, the system further includes a processor to receive and process the IR image from the IR sensor and the visible light image from the visible light sensor. In one implementation, the processor processes the visible light image to generate a 2-D image of the subject. In one implementation, the processor processes the IR image and the calculated distance to generate depth information for the 2-D image of the subject. In one implementation, the IR sensor is a time of flight sensor. In one implementation, the IR sensor includes the IR light source to operate as the time of flight sensor. In one implementation, the system further includes a visible light source including light from the natural environment to illuminate the subject. 
     In another implementation, a method is disclosed. The method includes: illuminating a subject with IR light using an IR light source; receiving reflected light including visible light and the IR light at a beam splitter; splitting the reflected light into two identical beams, a first beam and a second beam, using the beam splitter; receiving and processing the first beam at an IR sensor to pass the IR light and to block the visible light, to generate an IR image; receiving and processing the second beam at a visible light sensor to pass the visible light and to block the IR light, to generate a visible light image; and using a time of flight of the IR light transmitted by the IR light source and received by the IR sensor to calculate a distance of the subject from the beam splitter. 
     In one implementation, the method further includes processing the visible light image to generate a 2-D image of the subject. In one implementation, the method further includes processing the IR image and the calculated distance to generate depth information for the 2-D image of the subject. In one implementation, the method further includes illuminating the subject with visible light including light from the natural environment. In one implementation, the reflected light is formed as a beam of visible light and IR light. 
     In a further implementation, a non-transitory computer-readable storage medium storing a computer program to obtain depth information using an IR sensor with a beam splitter is disclosed. The computer program includes executable instructions that cause a computer to: command an IR light source to illuminate a subject with IR light; command a beam splitter to receive reflected light including visible light and the IR light; command the beam splitter to split the reflected light into two identical beams, a first beam and a second beam; command an IR sensor to process the first beam to pass the IR light and to block the visible light, to generate an IR image; command a visible light sensor to process the second beam to pass the visible light and to block the IR light, to generate a visible light image; and use a time of flight of the IR light transmitted by the IR light source and received by the IR sensor to calculate a distance of the subject from the beam splitter. 
     In one implementation, the computer program further includes executable instructions that cause the computer to: process the visible light image to generate a 2-D image of the subject. In one implementation, the computer program further includes executable instructions that cause the computer to: process the IR image and the calculated distance to generate depth information for the 2-D image of the subject. In one implementation, the computer program further includes executable instructions that cause the computer to: command a visible light source to illuminate the subject with visible light including light from the natural environment. In one implementation, the reflected light is formed as a beam of visible light and IR light. 
     Other features and advantages should be apparent from the present description which illustrates, by way of example, aspects of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The details of the present disclosure, both as to its structure and operation, may be gleaned in part by study of the appended drawings, in which like reference numerals refer to like parts, and in which: 
         FIG. 1  is a block diagram of a video system for obtaining depth information using an IR sensor with a beam splitter in accordance with one implementation of the present disclosure; 
         FIG. 2  is a flow diagram of a method for obtaining depth information using an IR sensor with a beam splitter in accordance with one implementation of the present disclosure; 
         FIG. 3A  is a representation of a computer system and a user in accordance with an implementation of the present disclosure; and 
         FIG. 3B  is a functional block diagram illustrating the computer system hosting the depth calculation application in accordance with an implementation of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     It is important to synchronize the data collected from the cameras and sensors in video production and/or studio environment. The collected data may be synchronized using the positions of the cameras and sensors. However, calibrating the cameras and sensors to control the positions can be difficult. For example, in using IR data from an IR sensor as depth information for visible light data from a visible light sensor, the positions of the two sensors (i.e., the IR sensor and the visible light sensor) need to be calibrated in order to synchronize the IR data with the visible light data. 
     Certain implementations of the present disclosure provide for systems and methods to capture video data of a subject using an infrared (IR) sensor and a visible light sensor (e.g., a red-green-blue (RGB) sensor) connected to a beam splitter which splits the input image into two identical images. Thus, the beam splitter provides an identical spatial perspective for the two images. Therefore, the identical spatial perspective for the two images obviates the need for the calibration of the positions of the two sensors. 
     After reading the below descriptions, it will become apparent how to implement the disclosure in various implementations and applications. Although various implementations of the present disclosure will be described herein, it is understood that these implementations are presented by way of example only, and not limitation. As such, the detailed description of various implementations should not be construed to limit the scope or breadth of the present disclosure. 
     In one implementation, a video system uses a beam splitter to split the beam two or more ways to a plurality of sensors, wherein each sensor is configured to filter the beam within a particular band of frequencies. In one example, a video system captures video data of a subject using an IR sensor and a visible light sensor connected to a beam splitter to split a beam (of visible light and IR ray) into two or more beams, wherein each of those beams comes from the same source. Thus, by connecting the IR sensor and the visible light sensor to a beam splitter, the IR sensor and the visible light sensor can receive the beam from the same source as though the visible light sensor and the IR sensor were at the same location. 
       FIG. 1  is a block diagram of a video system  100  for obtaining depth information using an IR sensor with a beam splitter in accordance with one implementation of the present disclosure. In  FIG. 1 , the video system  100  includes a beam splitter  110 , an IR sensor  120 , a visible light sensor  130 , and a processor  140 . The video system  100  may also include a visible light source  102  and an IR light source  104  to illuminate the subject  106 , which reflects the beam of visible and IR light  108  toward the beam splitter. The visible light source  102  may include artificial light as well as light from the natural environment to shine onto the subject  106 . In one implementation, the IR light source  104  is attached to or included in the IR sensor  120  to operate as a time of flight sensor, which measures the time it takes for the IR light to travel to the subject and back to the IR sensor  120 . In one implementation, the IR sensor  120  and the visible light sensor  130  are coupled to the beam splitter  110 . 
     In the illustrated implementation of  FIG. 1 , the subject  106  is illuminated by the visible light source  102  and the IR light source  104 . The illuminated light may then be reflected toward the beam splitter  110  as the beam of visible and IR light  108 . The beam splitter  110  receives the beam of visible and IR light  108  and splits the beam  108  into two identical beams and directs a first beam  112  toward the IR sensor  120  and a second beam  114  toward the visible light sensor  130 . 
     The IR sensor  120  may receive and process the first beam  112  to pass the IR light and to block the visible light. The visible light sensor  130  may receive and process the second beam  114  to pass the visible light and to block the IR light. Thus, in one implementation, the IR sensor  120  transmits the IR image  124  to the processor  140  and the visible light sensor  130  transmits the visible light image  132  to the processor  140 . As described above, the visible light image  132  and the IR image  124  have the identical spatial perspective since the images  132 ,  124  come from the same source (i.e., the beam splitter  110 ). 
     In one implementation, the processor  140  also communicates with the IR sensor  120  using messages  122  to measure and process the time of flight of the IR light transmitted by the IR light source  104  (of the IR sensor  120 ) and the first beam  112  received by the IR sensor  120 . The processor  140  may calculate the distance (d) of the subject from the beam splitter  110  using the time of flight. The depth may then be derived from the calculated distance (d). 
     In one implementation, the processor  140  processes the visible light image  132  as a 2-D image of the subject  106 , while the processor  140  processes the IR image  124  and the calculated distance (d) to provide depth information to the 2-D image. 
       FIG. 2  is a flow diagram of a method  200  for obtaining depth information using an IR sensor with a beam splitter in accordance with one implementation of the present disclosure. In  FIG. 2 , optional aspects are illustrated with a dashed line. 
     In the illustrated implementation of  FIG. 2 , a subject is illuminated with IR light using an IR light source, at step  210 . In one implementation, the IR light source is coupled to or included in the IR sensor, and is configured as a time-of-flight sensor. In some implementations, the subject may also be illuminated with visible light either using the visible light source or from the natural environment. The illuminated light may then be reflected toward and received by a beam splitter, at step  220 . The reflected light is formed as a beam of visible and IR light. The beam splitter then splits the beam of visible and IR light into two identical beams, and directs a first beam toward the IR sensor and a second beam toward the visible light sensor, at step  230 . 
     The IR sensor receives and processes the first beam to pass the IR light and to block the visible light, at step  240 . The visible light sensor receives and processes the second beam to pass the visible light and to block the IR light, at step  250 . Thus, in one implementation, the IR sensor transmits the IR image for processing, while the visible light sensor transmits the visible light image for processing. As described above, the visible light image and the IR image have the identical spatial perspective since the images come from the same source. 
     A time of flight of the IR light transmitted by the IR light source and received by the IR sensor is then used to calculate the distance of the subject from the beam splitter, at step  260 . In one implementation, the visible light image is processed as a 2-D image of the subject, while the calculated distance is processed to provide depth information to the 2-D image, at step  270 . 
       FIG. 3A  is a representation of a computer system  300  and a user  302  in accordance with an implementation of the present disclosure. The user  302  uses the computer system  300  to implement an application  390  for obtaining depth information using an IR sensor with a beam splitter as illustrated and described with respect to the processor  140  in  FIG. 1  and the method  200  in  FIG. 2 . 
     The computer system  300  stores and executes the depth calculation application  390  of  FIG. 3B . In addition, the computer system  300  may be in communication with a software program  304 . Software program  304  may include the software code for the depth calculation application  390 . Software program  304  may be loaded on an external medium such as a CD, DVD, or a storage drive, as will be explained further below. 
     Furthermore, the computer system  300  may be connected to a network  380 . The network  380  can be connected in various different architectures, for example, client-server architecture, a Peer-to-Peer network architecture, or other type of architectures. For example, network  380  can be in communication with a server  385  that coordinates engines and data used within the depth calculation application  390 . Also, the network can be different types of networks. For example, the network  380  can be the Internet, a Local Area Network or any variations of Local Area Network, a Wide Area Network, a Metropolitan Area Network, an Intranet or Extranet, or a wireless network. 
       FIG. 3B  is a functional block diagram illustrating the computer system  300  hosting the depth calculation application  390  in accordance with an implementation of the present disclosure. A controller  310  is a programmable processor and controls the operation of the computer system  300  and its components. The controller  310  loads instructions (e.g., in the form of a computer program) from the memory  320  or an embedded controller memory (not shown) and executes these instructions to control the system, such as to provide the data processing. In its execution, the controller  310  provides the depth calculation application  390  with a software system. Alternatively, this service can be implemented as separate hardware components in the controller  310  or the computer system  300 . 
     Memory  320  stores data temporarily for use by the other components of the computer system  300 . In one implementation, memory  320  is implemented as RAM. In one implementation, memory  320  also includes long-term or permanent memory, such as flash memory and/or ROM. 
     Storage  330  stores data either temporarily or for long periods of time for use by the other components of the computer system  300 . For example, storage  330  stores data used by the depth calculation application  390 . In one implementation, storage  330  is a hard disk drive. 
     The media device  340  receives removable media and reads and/or writes data to the inserted media. In one implementation, for example, the media device  340  is an optical disc drive. 
     The user interface  350  includes components for accepting user input from the user of the computer system  300  and presenting information to the user  302 . In one implementation, the user interface  350  includes a keyboard, a mouse, audio speakers, and a display. The controller  310  uses input from the user  302  to adjust the operation of the computer system  300 . 
     The I/O interface  360  includes one or more I/O ports to connect to corresponding I/O devices, such as external storage or supplemental devices (e.g., a printer or a PDA). In one implementation, the ports of the I/O interface  360  include ports such as: USB ports, PCMCIA ports, serial ports, and/or parallel ports. In another implementation, the I/O interface  360  includes a wireless interface for communication with external devices wirelessly. 
     The network interface  370  includes a wired and/or wireless network connection, such as an RJ-45 or “Wi-Fi” interface (including, but not limited to 802.11) supporting an Ethernet connection. 
     The computer system  300  includes additional hardware and software typical of computer systems (e.g., power, cooling, operating system), though these components are not specifically shown in  FIG. 3B  for simplicity. In other implementations, different configurations of the computer system can be used (e.g., different bus or storage configurations or a multi-processor configuration). 
     The description herein of the disclosed implementations is provided to enable any person skilled in the art to make or use the present disclosure. Numerous modifications to these implementations would be readily apparent to those skilled in the art, and the principals defined herein can be applied to other implementations without departing from the spirit or scope of the present disclosure. Although the above description includes systems and methods for reducing the image circle in video production including the film production and the broadcast, the described systems and methods are applicable in other field such as in medical imaging. 
     Variations to the system are also possible. For example, in one implementation, the system includes multiple camera rigs, some or all of which have beam splitters. In another implementation, the system uses a beam splitter that splits light into three or more beams, each for a respective camera or sensor. 
     Additional variations and implementations are also possible. For example, in addition to video production for movies or television, implementations of the system and methods can be applied and adapted for other applications, such as virtual reality content, virtual production (e.g., virtual reality environments), or motion capture. 
     All features of each of the above-discussed examples are not necessarily required in a particular implementation of the present disclosure. Further, it is to be understood that the description and drawings presented herein are representative of the subject matter which is broadly contemplated by the present disclosure. It is further understood that the scope of the present disclosure fully encompasses other implementations that may become obvious to those skilled in the art and that the scope of the present disclosure is accordingly limited by nothing other than the appended claims.