Patent Publication Number: US-2021173057-A1

Title: Method and System for Calibrating Time-Of-Flight Module, and Storage Medium

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation application of International Application No. PCT/CN2019/090072, filed on Jun. 5, 2019, which claims priority from Chinese Patent Application No. 201810963379.4, filed on Aug. 22, 2018, the entire contents of both of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosure relates to a field of three-dimensional image technologies, and more particularly to a method for calibrating a time-of-flight module, a system for calibrating a time-of-flight module and a storage medium. 
     BACKGROUND 
     A time of flight (TOF) module may calculate depth information of a measured object by calculating a time difference between a time point at which a light emitter emits an optical signal and a time point at which a light receiver receives the optical signal 
     SUMMARY 
     Embodiments of the disclosure provide a method for calibrating a time-of-flight module, a system for calibrating a time-of-flight module and a storage medium. 
     Implementations of the disclosure disclose a method for calibrating a time-of-flight module. The time-of-flight module includes a light emitter and a light detector. The light emitter includes a light source. The time-of-flight module is disposed on an electronic device. The electronic device includes an optical element. The method includes: emitting, by the light source, optical signals at a predetermined working current; and receiving, by the light detector, the optical signals reflected by the optical element to form calibration electrical signals. 
     Implementations of the disclosure disclose a system for calibrating a time-of-flight module. The system includes a time-of-flight module, including a light emitter and a light detector, wherein, the light emitter includes a light source; an electronic device having the time-of-flight module disposed thereon, and including an optical element. The light source is configured to emit optical signals at a predetermined working current; and the light detector is configured to receive the optical signals reflected by the optical element to form calibration electrical signals. 
     Implementations of the disclosure disclose a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable the computer execute a method for calibrating a time-of-flight module. The method includes: emitting, by a light source, optical signals at a predetermined working current; and receiving, by a light detector, the optical signals reflected by an optical element to form calibration electrical signals. 
     Additional aspects and advantages of the disclosure may be set forth in part in the following description, and may become obvious in part from the following description, or may be learned by practice of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and/or additional aspects and advantages of the disclosure will become more apparent and be understood more easily with reference to accompanying drawings and descriptions for implementations, in which: 
         FIG. 1  is a schematic diagram illustrating a three-dimensional structure of a calibration system according to some implementations of the disclosure; 
         FIG. 2  is a schematic diagram illustrating a light emitter of a time-of-flight module according to some implementations of the disclosure; 
         FIG. 3 - FIG. 9  are flow charts illustrating a method for calibrating a time-of-flight module according to some implementations of the disclosure; 
         FIG. 10  is a schematic diagram illustrating an arrangement of light emitting elements of a time-of-flight module according to some implementations of the disclosure; 
         FIG. 11 - FIG. 12  are flow charts illustrating a method for calibrating a time-of-flight module according to some implementations of the disclosure; 
         FIG. 13  and  FIG. 14  are schematic diagrams illustrating an arrangement of light emitting elements of a time-of-flight module according to some implementations of the disclosure; 
         FIG. 15  is a schematic diagram illustrating a three-dimensional structure of an electronic device according to some implementations of the disclosure; 
         FIG. 16  is a schematic diagram illustrating a three-dimensional structure of a time-of-flight module according to some implementations of the disclosure; 
         FIG. 17  is a schematic diagram illustrating a plane structure of a time-of-flight module according to some implementations of the disclosure; and 
         FIG. 18  is a schematic diagram illustrating a cross section of a time-of-flight module along a line XVIII-XVIII in  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION 
     Description will be made in detail below to embodiments of the disclosure. Examples of those embodiments are illustrated in accompanying drawings. Same or similar reference numerals refer to same or similar elements or elements having same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the disclosure, and should not be construed as a limitation of the disclosure. 
     Please refer to  FIG. 1  and  FIG. 2  together. The disclosure provides a method for calibrating a time-of-flight module  300 . The time-of-flight module  300  includes a light emitter  100  and a light detector  63 , and the light emitter  100  includes a light source  10 . The time-of-flight module  300  is disposed on an electronic device  800 . The electronic device  800  includes an optical element. The method includes: controlling the light source  10  to emit optical signals at a predetermined working current; and controlling the light detector  63  to receive the optical signals reflected by the optical element to form calibration electrical signals. 
     Please refer to  FIG. 2 . In some implementations, the optical element includes a diffuser  20  of the light emitter  100 . The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals includes: controlling the light detector  63  to receive the optical signals reflected by the diffuser  20  to form the calibration electrical signals. 
     Please refer to  FIG. 2 . In some implementations, the optical element includes the diffuser  20  of the light emitter  100  and a protective cover  40 . The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals includes: controlling the light detector  63  to receive the optical signals reflected by the diffuser  20  and the protective cover  40  to form the calibration electrical signals. 
     Please refer to  FIG. 1  and  FIG. 2  together. In some implementations, the optical element includes the diffuser  20  of the light emitter  100  and a cover plate  807 . The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals includes: controlling the light detector to receive the optical signals reflected by the diffuser and the cover plate to form the calibration electrical signals. 
     Please refer to  FIG. 1  and  FIG. 2  together. In some implementations, the optical element includes the diffuser  20  of the light emitter  100 , the protective cover  40 , and the cover plate  807 . The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals includes: controlling the light detector  63  to receive the optical signals reflected by the diffuser  20 , the protective cover  40 , and the cover plate  807  to form the calibration electrical signals. 
     Please refer to  FIG. 2  and  FIG. 10  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting element group. The controlling the light source  10  to emit the optical signals at the predetermined working current includes: controlling light emitting elements  11  in the multiple light-emitting element groups to simultaneously emit the optical signals. The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals includes: controlling the multiple light detecting elements to correspondingly receive the optical signals emitted by the multiple light-emitting element groups, and to convert the optical signals into the multiple electrical signals as the calibration electrical signals corresponding to the multiple light-emitting element groups. 
     Please refer to  FIG. 2  and  FIG. 10  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting, element group. The controlling the light source  10  to emit the optical signals at the predetermined working current includes: controlling light emitting elements  11  in the multiple light-emitting element groups to respectively emit the optical signals at different times. The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals includes: controlling the multiple light detecting elements to be turned on sequentially, and each light detecting element is turned on in response to turning on of the corresponding light-emitting element group, and controlling each turned on light detecting element to receive the optical signals emitted by the light emitting elements  11  in the turned on light-emitting element group, and to convert the optical signals into an electrical signal as the calibration electrical signal corresponding to the light-emitting element group. 
     Please refer to  FIG. 2  and  FIG. 10  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting, element group. The controlling the light source  10  to emit the optical signals at the predetermined working current includes: controlling light emitting elements in the multiple light-emitting element groups to respectively emit the optical signals at different times. The controlling the light detector  63  to receive the optical signals reflected by the optical element  11  to form the calibration electrical signals includes: controlling the multiple light detecting elements to be turned on simultaneously and to sequentially receive the optical signals each group emitted by the light emitting elements  11  in the turned on light-emitting element group, and to convert the optical signals into multiple electrical signals; and obtaining the calibration electrical signal corresponding to each light-emitting element group based on the multiple electrical signals corresponding each to each light-emitting element group and a weight corresponding to each electrical signal. 
     Please refer to  FIG. 8 . In some implementations, before controlling the light source  10  to emit the optical signals at the predetermined working current, the method also includes: calculating the predetermined working current based on a preset distance. 
     Please refer to  FIG. 1  and  FIG. 2 . The disclosure also provides a calibration controller  806  for the time-of-flight module  300 . The time-of-flight module  300  includes a light emitter  100  and a light detector  63 . The light emitter  100  includes a light source  10 . The time-of-flight module  300  is disposed on an electronic device  800 . The electronic device  800  includes an optical element. The calibration controller  806  may be configured to: control the light source  10  to emit optical signals at a predetermined working current; and control the light detector  63  to receive the optical signals reflected by the optical element to form calibration electrical signals. 
     Please refer to  FIG. 1  and  FIG. 2  together. In some implementations, the optical element includes a diffuser  20  of the light emitter  100 . The calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20  to form the calibration electrical signals. 
     Please refer to  FIG. 1  and  FIG. 2  together. In some implementations, the optical element includes the diffuser  20  of the light emitter  100  and a protective cover  40 . The calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20  and the protective cover  40  to form the calibration electrical signals. 
     Please refer to  FIG. 1  and  FIG. 2  together. In some implementations, the optical element includes the diffuser  20  of the light emitter  100  and a cover plate  807 . The calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20  and the cover plate  807  to form the calibration electrical signals. 
     Please refer to  FIG. 1  and  FIG. 2  together. In some implementations, the optical element includes the diffuser  20  of the light emitter  100 , the protective cover  40 , and the cover plate  807 . The calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20 , the protective cover  40 , and the cover plate  807  to form the calibration electrical signals. 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 10  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting element group. The calibration controller  806  may be configured to control light emitting elements  11  in the multiple light-emitting element groups to simultaneously emit the optical signals; and control the multiple light detecting elements to correspondingly receive the optical signals emitted by the multiple light-emitting element groups, and to convert the optical signals into multiple electrical signals as the calibration electrical signals corresponding to the multiple light-emitting element groups. 
     Please refer to  FIG. 2  and  FIG. 10  together. In some implementations, the light emitter  100  comprises multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting element group. The calibration controller  806  may be configured to: control light emitting elements  11  in the multiple light-emitting element groups to respectively emit the optical signals at different times; and control the multiple the light detecting elements to be turned on sequentially, and each light detecting element is turned on in response to turning on of the corresponding light-emitting element group, and to receive the optical signals emitted by the light emitting elements  11  in the turned on light-emitting element group, and to convert the optical signals into an electrical signal as the calibration electrical signal corresponding to the light-emitting element group. 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 10  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting element group. The calibration controller  806  may be configured to: control light emitting elements  11  in the multiple light-emitting element groups to respectively emit the optical signals at different times; control the multiple light detecting elements to be turned on simultaneously and to sequentially receive the optical signals each group emitted by the light emitting elements in the turned on light-emitting element group, and to convert the optical signals into multiple electrical signals; and obtain the calibration electrical signal corresponding to each light-emitting element group based on the multiple electrical signals each corresponding to each light-emitting element group and a weight corresponding to each electrical signal. 
     Please refer to  FIG. 1 . In some implementations, the calibration controller  806  may be configured to: calculate the predetermined working current based on a preset distance. 
     Please refer to  FIG. 1 . The disclosure also provides a calibration system  1000 . The calibration system  1000  includes a time-of-flight module  300 , an electronic device  800  and a calibration controller  806 . The time-of-flight module  300  includes a light emitter  100  and a light detector  63 . The time-of-flight module  300  is disposed on the electronic device  800 . The electronic device  800  includes an optical element. The calibration controller  806  may be configured to control a light source  10  to emit optical signals at a predetermined working current, and to control the light detector  63  to receive optical signals reflected by the optical element to form calibration electrical signals. 
     Please refer to  FIG. 1  and  FIG. 2 . The disclosure provides a calibration system  1000 . The calibration system  1000  includes a time-of-flight module  300 , an electronic device  800  and a calibration controller  806 . The time-of-flight module  300  includes a light emitter  100 , a light receiver  200  and a light detector  63 . The light emitter  100  includes a light source  10 . The light source  10  may emit optical signals. The light receiver  200  may receive the optical signals emitted by the light emitter  100 . The light detector  63  is disposed on a circuit board  50  (illustrated in  FIG. 18 ). The time-of-flight module  300  is disposed on the electronic device  800 . The electronic device  800  may be a mobile phone, a tablet computer, a notebook computer, or a wearable device (such as a smart watch, a smart bracelet, smart glasses, a smart helmet, etc.), which is not limited here. The electronic device  800  includes an optical element. The optical element reflects the optical signals emitted by the light emitter  100 . The light detector  63  may receive the optical signals reflected by the optical element. 
     The calibration controller  806  may be a processer, such as a micro control unit (MCU). 
     Please refer to  FIG. 1  to  FIG. 3 . The disclosure also provides a method for calibrating a time-of-flight module  300 . The method includes the following. 
     At block  02 , the light source  10  is controlled to emit optical signals at a predetermined working current. 
     At block  03 , the light detector  63  is controlled to receive the optical signals reflected by the optical element to form calibration electrical signals. 
     Please refer to  FIG. 1  to  FIG. 3  together. The disclosure also provides a calibration controller  806 . The calibration controller may be configured in the above calibration system  1000 . In some implementations, the calibration controller  806  may be integrated in an electronic device  800  (illustrated in  FIG. 1 ) or disposed outside the electronic device  800  (not illustrated). In addition, in some implementations, while the calibration controller  806  may be integrated within the electronic device  800 , the calibration controller  806  may be further integrated in a processor  805  of the electronic device  800 . The method for calibrating the time-of-flight module  300  according to implementations of the disclosure may be implemented by the calibration controller  806 . The action at blocks  02  and  03  may be realized by the calibration controller  806 . That is, the calibration controller  806  may be configured to control the light source  10  to emit the optical signals at the predetermined working current, and to control the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals. 
     In detail, the time-of-flight module  300  may obtain depth information of an object in a target space in an indirectly obtaining way. In the indirectly obtaining way, the light emitter  100  emits the optical signals to the target space, and the light receiver  200  receives the optical signals reflected by the object in the target space and divides the optical signals into two parts. The processor  805  in the electronic device  800  may calculate a time-of-flight of the optical signals in the target space based on the two parts of the optical signals received by the light receiver  200 , and further calculate the depth information of the object in the target space based on the time-of-flight and a light speed. In this way, the obtained depth information may have high accuracy when actually light-emitting power of the light emitter  100  is large enough. It may be understood that, when the actual light-emitting power of the light emitter  100  is small, the optical signals emitted into the target space may be excessively lost due to a reason such as a long time of flight, or partially absorbed by the target object, which may cause a problem that the optical signals may not be reflected to be received by the light receiver  200 , thereby causing that the light receiver  200  may not receive the reflected optical signal to calculate the time of flight of the target object, and may not further obtain the depth information of the target object, or cause a problem that only a small part of the optical signals are reflected and received by the light receiver  200 , but the optical signals received by the light receiver  200  are too small, and the accuracy of the depth information of the target object calculated based on such part of the optical signals is low. 
     In order to improve the accuracy of obtaining the depth information, the light detector  63  may be disposed in the light emitter  100  to detect the actually light-emitting power of the light source  10  in the light emitter  100 . When the actually light-emitting power is less than a target light-emitting power, a working current of the light source  10  is increased to improve the accuracy of obtaining the depth information. When the actually light-emitting power is greater than the target light-emitting power, the working current of the light source  10  may be reduced to reduce a power consumption of the time-of-flight module  300 . The target light-emitting power may be calibrated. 
     In detail, in the calibration method and calibration system  1000  according to implementations of the disclosure, the target light-emitting power is calibrated before the time-of-flight module  300  leaves a factory. The calibration controller  806  is configured to drive the light source  10  to emit the optical signals at the predetermined working current, and the light detector  63  is configured to receive the optical signals reflected by the optical element and to convert the optical signals into electrical signals. The electrical signals may be detection current, and the electrical signals may be calibration electrical signals of the light emitter  100 . The calibration electrical signals are used to indirectly characterize the target light-emitting power of the light source  10 . When the time-of-flight module  300  is used subsequently, the processor  805  of the electronic device  800  drives the light source  10  to emit the optical signals with the same predetermined working current, and the light detector  63  receives the optical signals reflected by the optical element and converts the optical signals into real-time electrical signals at the current time point. The real-time electrical signal is used to indirectly characterize the actually light-emitting power of the light source  10 . The processor  805  compares the real-time electrical signal each with the calibration electrical signal. When the real-time electrical signal is lower than the calibration electrical signal, the processor  805  adjusts the working current of the light source  10  to increase the actually light-emitting power of the light source  10 , such that the light-emitting power of the light source  10  may meet a requirement for an accuracy of the depth information. When the real-time electrical signal is greater than the calibration electrical signal, the processor  805  may reduce the working current of the light source  10  to reduce the actually light-emitting power of the light source  10 , thereby meeting the requirement for the accuracy of the depth information and reducing the power consumption of the time-of-flight module  300 . When the real-time electrical signal is equal to the calibration electrical signal, the processor  805  may not perform any action. 
     With the calibration method, the calibration controller  806  and the calibration system  1000  according to implementations of the disclosure, the calibration electrical signal that may characterize the target light-emitting power of the light source  10  is calibrated in advance by the light detector  63 . In this way, when the time-of-flight module  300  is used subsequently, the working current of the light source  10  may be conveniently adjusted based on the calibration electrical signals calibrated in advance, such that the light source  10  has an enough light-emitting power and the requirement for the accuracy of the depth information is met. 
     Please refer to  FIG. 2  and  FIG. 4  together. In some implementations, the optical element includes a diffuser  20  of the light emitter  100 . The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals at block  03  includes the following. 
     At block  031 , the light detector  63  is controlled to receive the optical signals reflected by the diffuser  20  to form the calibration electrical signals. 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 4  together. In some implementations, the action at block  031  may be implemented by the calibration controller  806 . That is, the calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20  to form the calibration electrical signals. 
     It may be understood that, the light emitter  100  generally includes the light source  10  and the diffuser  20 . The light source  10  is configured to emit the optical signals, such as infrared laser signals. The diffuser  20  is configured to diffuse the optical signals emitted by the light source  10 , to enabled light emitted into the target space to be uniform surface light. However, a light transmittance of the diffuser  20  may not generally reach 100%. Most of the optical signals emitted by the light source  10  may be diffused out through the diffuser  20 , and a small part of the optical signals may be reflected by the diffuser  20 . The light detector  63  is disposed in the light emitter  100 , and a light receiving surface of the light detector  63  is toward to the diffuser  20 . In this way, the light detector  63  may receive the optical signals reflected by the diffuser  20  and convert the optical signals into the electrical signals for outputting during calibration. The output electrical signals may be stored in the electronic device  800  as the calibration electrical signals. When the time-of-flight module  300  is used subsequently, the light detector  63  also receives the optical signals reflected by the diffuser  20  and converts the optical signals into the real-time electrical signals for outputting, and the processor  805  adjusts the working current of the light source  10  based on a comparing result between the real-time electrical signals and the calibration electrical signals. 
     Please refer to  FIG. 2  to  FIG. 5 . In some implementations, the optical element includes the diffuser  20  of the light emitter  100  and a protective cover  40 . The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals at block  03  includes the following. 
     At block  032 , the light detector  63  is controlled to receive the optical signals reflected by the diffuser  20  and the protective cover  40  to form the calibration electrical signals. 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 5  together. In some implementations, the action at block  032  may be implemented by the calibration controller  806 . That is, the calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20  and the protective cover  40  to form the calibration electrical signals. 
     In detail, the light emitter  100  generally includes the light source  10  and the diffuser  20 . The light source  10  is configured to emit the optical signals, such as the infrared laser signals. The diffuser  20  is configured to diffuse the optical signals emitted by the light source  10 , to enable the light emitted into the target space to be the uniform surface light. Further, the light emitter  100  may further include the protective cover  40 . The diffuser  20  and the protective cover  40  are sequentially disposed along a light emitting direction of the light source  10 . On the one hand, the protective cover  40  may prevent the diffuser  20  from falling off the light emitter  100 . On the other hand, the protective cover  40  may provide protection against dust and water and the like for the diffuser  20 . It may be understood that, the light transmittance of the diffuser  20  may not generally reach 100%. Most of the optical signals emitted by the light source  10  may be diffused out through the diffuser  20 , and a small part of the optical signals may be reflected by the diffuser  20 . Similarly, a light transmittance of the protective cover  40  may not generally reach 100%. Most of the optical signals emitted through the diffuser  20  may be emitted into the target space through the protective cover  40 , and a small part of the optical signals may be reflected back by the protective cover  40 . The light detector  63  is disposed in the light emitter  100 , and the light receiving surface of the light detector  63  is toward to the diffuser  20 . In this way, the light detector  63  may receive the optical signals reflected by the diffuser  20  and the protective cover  40 , and convert the optical signals into electrical signals for outputting during calibration. The output electrical signals may be stored in the electronic device  800  as the calibration electrical signals. In the subsequent use of the time-of-flight module  300 , the light detector  63  also receives the optical signals reflected by the diffuser  20  and the protective cover  40 , and converts the optical signals into the real-time electrical signals for outputting. The processor  805  adjusts the working current of the light source  10  based on a comparing result between the real-time electrical signals and the calibration electrical signals. 
     It may be understood that, when the protective cover  40  is not added into the time-of-flight module  300  used in the calibration procedure, the optical signals received by the light detector  63  only includes the optical signals reflected by the diffuser  20 , and the calibration electrical signal obtained at this time is assumed as I 0 . When the protective cover  40  is disposed on the time-of-flight module  300  in an actual using procedure, the optical signals received by the light detector  63  include both the part of the optical signals reflected by the diffuser  20  and the part of the optical signals reflected by the protective cover  40 , and the real-time electrical signal obtained at this time is assumed as I 1 . In the actual using procedure of the time-of-flight module  300 , the optical signals received by the light detector  63  additionally include the optical signals reflected by the protective cover  40 , a condition I 1 &gt;I 0  may occur. The processor  805  considers that the actually light-emitting power of the light source  10  at this time is greater than the target light-emitting power after obtaining a result I 1 &gt;I 0 , and reduces the working current of the light source  10 . However, in fact, when the light detector  63  only receives the optical signals reflected by the diffuser  20 , but does not receive the optical signals reflected by the protective cover  40 , the real-time electrical signal output by the light detector  63  is I 2  (assuming I 2 &lt;I 0 ), in other words, the actually light-emitting power of the light source  10  is lower than the target light-emitting power, and the processor  805  is supposed to increase the working current of the light source  10 . However, since composition of the optical signals received by the light detector  63  in the actual using procedure is different from that of the optical signals received in the calibration procedure, the actual light-emitting power detected in the actual using procedure is inaccurate, further caused that the processor  805  incorrectly adjusts the working current of the light source  10 . 
     Therefore, when the time-of-flight module  300  is disposed with the protective cover  40  before leaving the factory, the time-of-flight module  300  is also disposed with a protective cover  40  consistent with the protective cover  40  when leaving the factory in the calibration procedure. In this way, a calibration scene of the time-of-flight module  300  is approximately similar to a using scene of the time-of-flight module  300 . The calibration electrical signal includes the optical signals reflected by the diffuser  20  and the optical signals reflected by the protective cover  40 , and the real-time electrical signal also includes the optical signals reflected by the diffuser  20  and the optical signals reflected by the protective cover  40 . The processor  805  may take the calibration electrical signal as a reference signal to accurately adjust a driving current of the light source  10 . 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 6  together. In some implementations, the optical element includes the diffuser  20  of the light emitter  100  and a cover plate  807  of the electronic device  800 . The cover plate  807  may be disposed on a surface where a display screen  802  of the electronic device  800  is located, in which case the time-of-flight module  300  is a front module. The cover plate  807  may also be disposed on a surface of the electronic device  800  opposite to the surface where the display screen  802  is located, in which case the time-of-flight module  300  is a rear module. The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals at block  03  includes the following. 
     At block  033 , the light detector  63  is controlled to receive the optical signals reflected by the diffuser  20  and the cover plate  807  to form the calibration electrical signals. 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 6  together. In some implementations, the action at block  032  may be implemented by the calibration controller  806 . That is, the calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20  and the cover plate  807  to form the calibration electrical signals. 
     In detail, the light emitter  100  generally includes the light source  10  and the diffuser  20 . The light source  10  is configured to emit the optical signals, such as the infrared laser signals. The diffuser  20  is configured to diffuse the optical signals emitted by the light source  10 , to enable the light emitted into the target space to be the uniform surface light. Further, the light emitter  100  is generally housed within a housing  801  of the electronic device  800  when the light emitter  100  is disposed in the electronic device  800 . An emitting window of the light emitter  100  corresponding to the housing  801  is generally disposed with the cover plate  807 , to enable the optical signal emitted by the light emitter  100  to be emitted, and to provide protection against dust and water and the like for the light emitter  100 . It may be understood that, the light transmittance of the diffuser  20  may not generally reach 100%. Most of the optical signals emitted by the light source  10  may diffuse out through the diffuser  20 , and a small part of the optical signals may be reflected by the diffuser  20 . Similarly, a light transmittance of the cover plate  807  may not generally reach 100%. Most of the optical signals emitted through the diffuser  20  may be emitted into the target space through the cover plate  807 , and a small part of the optical signals may be reflected back by the cover plate  807 . The light detector  63  is disposed in the light emitter  100 , and the light receiving surface of the light detector  63  is toward to the diffuser  20 . In this way, in the calibration procedure, the light detector  63  may receive the optical signals reflected by the diffuser  20  and the cover plate  807 , and convert the optical signals into electrical signals for outputting, and the output electrical signals may be stored in the electronic device  800  as the calibration electrical signals. When the time-of-flight module  300  is used subsequently, the light detector  63  also receives the optical signals reflected by the diffuser  20  and the cover plate  807 , and converts the optical signals into real-time electrical signals for outputting. The processor  805  then adjusts the working current of the light source  10  based on a comparing result between the real-time electrical signals and the calibration electrical signals. 
     It may be understood that, when the cover plate  807  is not added into the time-of-flight module  300  used in the calibration procedure, the optical signals received by the light detector  63  only include the optical signals reflected by the diffuser  20  and the calibration electrical signal obtained at this time is assumed as I 0 . However, since the cover plate  807  is disposed on the time-of-flight module  300  in the actual using procedure, the optical signals received by the light detector  63  include both the optical signals reflected by the diffuser  20  and the optical signals reflected by the cover plate  807 , and the real-time electrical signal obtained at this time is assumed as I 3 . In the actual using procedure of the time-of-flight module  300 , the optical signals received by the light detector  63  additionally include the optical signals reflected by the cover plate  807 . In this case, a condition I 3 &gt;I 0  may occur. The processor  805  considers that the actual light-emitting power of the light source  10  at this time is greater than the target light-emitting power after obtaining a result I 3 &gt;I 0 , and reduces the working current of the light source  10 . However, in fact, when the light detector  63  only receives the optical signals reflected by the diffuser  20 , but does not receive the optical signals reflected by the cover plate  807 , the real-time electrical signal output by the light detector  63  is I 4  (assuming I 4 &lt;I 0 ), in other words, the actually light-emitting power of the light source  10  is lower than the target light-emitting power, and the processor  805  is supposed to increase the working current of the light source  10 . However, since composition of the optical signals received by the light detector  63  in the actual using procedure is different from that of the optical signals received in the calibration procedure, the actual light-emitting power detected in the actual using procedure is inaccurate, further caused that the processor  805  incorrectly adjusts the working current of the light source  10 . 
     Therefore, since the time-of-flight module  300  is disposed on the electronic device  800 , and the electronic device  800  is disposed with the cover plate  807 , the time-of-flight module  300  is also disposed with a cover plate  807  consistent with the cover plate  807  disposed on the electronic device  800  in the calibration procedure. In this way, the calibration scene of the time-of-flight module  300  is approximately similar to the using scene of the time-of-flight module  300 . The calibration electrical signal includes the optical signals reflected by the diffuser  20  and the optical signals reflected by the cover plate  807 , and the real-time electrical signal also includes the optical signals reflected by the diffuser  20  and the optical signals reflected by the cover plate  807 . The processor  805  may take the calibration electrical signal as a reference signal to accurately adjust the driving current of the light source  10 . 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 7  together. In some implementations, the optical element includes the diffuser  20  of the light emitter  100 , the protective cover  40  of the light emitter  100 , and the cover plate  807  of the electronic device  800 . The cover plate  807  may be disposed on the surface where the display screen  802  of the electronic device  800  is located, in which case the time-of-flight module  300  is the front module. The cover plate  807  may also be a cover plate  807  disposed on the surface of the electronic device  800  opposite to the surface where the display screen  802  is located, in which case the time-of-flight module  300  is the rear module. The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals at block  03  includes the following. 
     At block  034 , the light detector  63  is controlled to receive optical signals reflected by the diffuser  20 , the protective cover  40 , and the cover plate  807  to form calibration electrical signals. 
     Please refer to  FIG. 1 ,  FIG. 2  and  FIG. 7  together. In some implementations, the action at block  034  may be implemented by the calibration controller  806 . That is, the calibration controller  806  may also be configured to control the light detector  63  to receive the optical signals reflected by the diffuser  20 , the protective cover  40 , and the cover plate  807  to form the calibration electrical signals. 
     In detail, the light emitter  100  generally includes the light source  10  and the diffuser  20 . The light source  10  is configured to emit the optical signals, such as the infrared laser signals. The diffuser  20  is configured to diffuse the optical signals emitted by the light source  10 , to enable the light emitted into the target space to be the uniform surface light. Further, the light emitter  100  may also include the protective cover  40 . The diffuser  20  and the protective cover  40  are sequentially disposed along the light emitting direction of the light source  10 . On the one hand, the protective cover  40  may prevent the diffuser  20  from falling off from the light emitter  100 . On the other hand, the protective cover  40  may provide protection against dust and water and the like for the diffuser  20 . Further, the light emitter  100  is generally housed in the housing  801  of the electronic device  800  when installed in the electronic device  800 . The cover plate  807  is generally disposed on the emitting window of the light emitter  100  corresponding to the housing  801 , to enable the optical signals emitted by the light emitter  100  to be emitted, and to provide protection against dust and water and the like for the light emitter  100 . It may be understood that, the light transmittance of the diffuser  20  may not generally reach 100%. Most of the optical signals emitted by the light source  10  may be diffused out through the diffuser  20 , and a small part of the optical signals may be reflected by the diffuser  20 . Similarly, the light transmittance of the protective cover  40  may not generally reach 100%. Most of the optical signals emitted through the diffuser  20  may be emitted into the target space through the protective cover  40 , and a small part of the optical signals may be reflected back by the protective cover  40 . Similarly, the light transmittance of the cover plate  807  may not generally reach 100%. Most of the optical signals emitted through the diffuser  20  may be emitted into the target space through the cover plate  807 , and a small part of the optical signals may be reflected back by the cover plate  807 . The light detector  63  is disposed in the light emitter  100 , and the light receiving surface of the light detector  63  is toward to the diffuser  20 . In this way, in the calibration procedure, the light detector  63  may receive the optical signals reflected by the diffuser  20 , the protective cover  40  and the cover plate  807 , and convert the optical signals into the electrical signals for outputting. The output electrical signals may be stored in the electronic device  800  as the calibration electrical signals. In the subsequent use of the time-of-flight module  300 , the light detector  63  also receives the optical signals reflected by the diffuser  20 , the optical signals reflected by the protective cover  40  and the optical signals reflected by the cover plate  807 , and converts all the optical signals into real-time electrical signals for outputting. The processor  805  then adjusts the working current of the light source  10  based on a comparing result between the real-time electrical signals each and the calibration electrical signal. 
     It may be understood that, when the protective cover  40  and the cover plate  807  are not added into the time-of-flight module  300  used in the calibration procedure, the optical signals received by the light detector  63  only include the optical signals reflected by the diffuser  20 , and the calibration electrical signal obtained at this time is assumed as I 0 . However, in the actual using procedure of the time-of-flight module  300 , since the time-of-flight module  300  is disposed with the protective cover  40 , and the electronic device  800  is disposed with the cover plate  807 , the optical signals received by the light detector  63  includes the optical signals reflected by the diffuser  20 , the optical signals reflected by the protective cover  40  and the optical signals reflected by the cover plate  807 , and the real-time electrical signal obtained at this time is assumed as I 5 . In the actual using procedure of the time-of-flight module  300 , the optical signals received by the light detector  63  additionally include the optical signals reflected by the protective cover  40  and the optical signals reflected by the cover plate  807 . In this case, a condition I 5 &gt;I 0  may occur. The processor  805  considers that the actually light-emitting power of the light source  10  at this time is greater than the target light-emitting power after obtaining a result I 5 &gt;I 0 , and reduce the working current of the light source  10 . However, in fact, when the light detector  63  only receives the optical signals reflected by the diffuser  20 , but does not receive the optical signals reflected by the protective cover  40  and the cover plate  807 , the real-time electrical signal output by the light detector  63  is I 6  (assuming I 6 &lt;I 0 ), in other words, the actually light-emitting power of the light source  10  is lower than the target light-emitting power, and the processor  805  is supposed to increase the working current of the light source  10 . However, since the composition of the optical signals received by the light detector  63  in the actual using procedure is different from the composition of the optical signals received in the calibration procedure, the actual light-emitting power detected in the actual using procedure is inaccurate, further caused that the processor  805  incorrectly adjusts the working current of the light source  10 . 
     Therefore, the time-of-flight module  300  is disposed with the protective cover  40  when the time-of-flight module  300  is actually used, and the electronic device  800  is disposed with the cover plate  807  when the time-of-flight module  300  is disposed on the electronic device  800 , so the time-of-flight module  300  is also disposed with a protective cover  40  consistent with the protective cover  40  when leaving the factory and a cover plate  807  consistent with the cover plate  807  disposed on the electronic device  800  in the calibration procedure. In this way, the calibration scene of the time-of-flight module  300  is approximately similar to the using scene of the time-of-flight module  300 . The calibration electrical signal includes the optical signals reflected by the diffuser  20 , the optical signals reflected by the protective cover  40  and the optical signals reflected by the cover plate  807 . The real-time electrical signal also includes the optical signals reflected by the diffuser  20 , the optical signals reflected by the protective cover  40  and the optical signals reflected by the cover plate  807 . The processor  805  may take the calibration electrical signal as a reference signal to accurately adjust the driving current of the light source  10 . 
     Please refer to  FIG. 8 . In some implementations, before the action at block  02 , the method also includes the following. 
     At block  01 , the predetermined working current is calculated based on a preset distance. 
     Please refer to  FIG. 1  and  FIG. 8  together. In some implementations, the action at block  01  may also be implemented by the calibration controller  806 . In other words, the calibration controller  806  may be configured to calculate the predetermined working current based on the preset distance. 
     It may be understood that, when a distance between a target subject and the time-of-flight module  300  in a scene is closer, a smaller working current is used to drive the light source  10  to emit light. And more particularly, when the target subject is a user, since the optical signals emitted by the light source  10  is generally the infrared laser signals, energy of the optical signals emitted by the light source  10  is relatively higher when the driving current is larger at this time, which is likely to cause a damage to eyes of the user within a close range. When the distance between the target subject in the scene and the time-of-flight module  300  is longer, a larger working current is used to drive the light source  10  to emit light, thereby ensuring that the emitted optical signals may not be completely lost, and most of the optical signals may be reflected back and received by the light receiver  200 , thereby further ensuring that the depth information has a higher obtaining accuracy. Therefore, the time-of-flight module  300  may be driven by different predetermined working currents in the actual using procedure. The real-time electrical signals received by the light detector  63  are different when the driving is performed by different predetermined working currents. 
     Then, in the calibration procedure, the calibration controller  806  determines the calibration electrical signals respectively corresponding to the multiple predetermined working currents based on different predetermined working currents. In detail, first, working currents corresponding to the multiple preset distances are respectively calculated according to selected multiple preset distances. A calculation procedure may be: (1) obtaining a mapping relationship between the preset distances and the predetermined working currents based on multiple experimental data; and (2) obtaining predetermined working currents each corresponding to each preset distance based on a determined mathematical model, in which the calculation method is not limited here. Calibration currents each corresponding to each predetermined working current are calibrated in turn after the predetermined working currents are determined. For example, a calibrated corresponding relationship between the predetermined working currents and the calibration currents includes: I preset1 →I calibration 1 , I preset2 →I calibration2 , . . . . Then, in the subsequent actual using procedure of the time-of-flight module  300 , the processor  805  may adjust the working current of the light source  10  by comparing the real-time electrical signal with a calibration current I calibration 1  when the time-of-flight module  300  drives the light source  10  to emit the optical signals with a working current I preset1 , and the processor  805  adjusts the working current of the light source  10  by comparing the real-time electrical signal with a calibration current I calibration 2  when the time-of-flight module  300  drives the light source  10  to emit the optical signals with a working current I preset2 , and so on. 
     In this way, each calibration current corresponding to the predetermined working current is taken as a reference for adjusting the driving current of the light source  10 , thereby improving the accuracy of adjusting the driving current of the light source  10 , and further enabling the actually light-emitting power of the light source  10  closer to the target light-emitting power. 
     Please refer to  FIG. 2 ,  FIG. 9  and  FIG. 10  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting element group. The controlling the light source  10  to emit the optical signals at the predetermined working current at block  02  includes the following. 
     At block  021 , light emitting elements in the multiple light-emitting element groups are controlled to simultaneously emit the optical signals. 
     The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals at block  03  includes the following. 
     At block  035 , the multiple light detecting elements are controlled to correspondingly receive the optical signals emitted by the multiple light-emitting element groups, and to convert the optical signals into multiple electrical signals as the calibration electrical signals corresponding to the multiple light-emitting element groups. 
     Please refer to  FIG. 1 ,  FIG. 2 ,  FIG. 9  and  FIG. 10  together. In some implementations, the actions at blocks  021  and  035  both may be implemented by the calibration controller  806 . In other words, the calibration controller  806  may be configured to control the light emitting elements  11  in the multiple light-emitting element groups to simultaneously emit the optical signals, and to control the multiple light detecting elements to receive the optical signals emitted by the multiple light-emitting element groups, and to convert the optical signals into the multiple electrical signals as the calibration electrical signals corresponding to the multiple light-emitting element groups. 
     In detail, referring to  FIG. 10 , assumed that the light-emitting element groups in the light emitter  100  includes groups I, II, III, and IV, each light-emitting element group includes multiple light emitting elements  11 , and each light-emitting element group may be controlled independently. The light detector  63  includes four light detecting elements, i.e., a light detecting element A, a light detecting element B, a light detecting element C, and a light detecting element D. The light detecting element A is disposed at a center position of a light emitting area where the group I is located. The group I corresponds to the light detecting element A. The light detecting element A may receive optical signals emitted by light emitting elements  11  of the group I. The light detecting element B is disposed at a center position of a light emitting area where the group II is located. The group II corresponds to the light detecting element B. The light detecting element B may receive optical signals emitted by light emitting elements  11  of the group II. The light detecting element C is disposed at a center position of a light emitting area where the group III is located. The group III corresponds to the light detecting element C. The light detecting element C may receive optical signals emitted by light emitting elements  11  of the group III. The light detecting element D is disposed at a center position of a light emitting area where the group IV is located. The group IV corresponds to the light detecting element D. The light detecting element D may receive optical signals emitted by light emitting elements  11  of the group IV. 
     In the calibration procedure, the calibration controller  806  controls all the light emitting elements  11  in the groups I, II, III and IV to simultaneously emit light, and controls the light detecting elements A, B, C and D to be turned on simultaneously. The light detecting element A receives the optical signals emitted by the light emitting elements  11  of the group I. The light detecting element B receives the optical signals emitted by the light emitting elements  11  of the group II. The light detecting element C receives the optical signals emitted by the light emitting elements  11  of the group III. The light detecting element D receives the optical signals emitted by the light emitting elements  11  of the group IV. The light detecting element A converts the optical signals into an electrical signal and converts the electrical signal as a calibration electrical signal I calibration A  of the group I after receiving the optical signals emitted by the light emitting elements  11  of the group I. The light detecting element B converts the optical signals into an electrical signal and converts the electrical signal as a calibration electrical signal I calibration B  of the group II after receiving the optical signals emitted by the light emitting elements  11  of the group II. The light detecting element C converts the optical signals into an electrical signal and converts the electrical signal as a calibration electrical signal I calibration C  of the group III after receiving the optical signals emitted by the light emitting elements  11  of the group III. The light detecting element D converts the optical signals into an electrical signal and converts the electrical signal as a calibration electrical signal I calibration D  of the group IV after receiving the optical signals emitted by the light emitting elements  11  of the group IV. Therefore, each light emitter  100  has four calibration electrical signals, i.e., the I calibration A , the I calibration B , the I calibration C , and the I calibration D . 
     In the subsequent adjustment for the working current of the light source  10  of the time-of-flight module  300 , the processor  805  may control all the light emitting elements  11  in the groups I, II, III and IV to simultaneously emit the light, and control the light detecting elements A, B, C and D to be turned on simultaneously. The light detecting element A converts the optical signals into a real-time electrical signal I real A  of the group I after receiving the optical signals emitted by the light emitting elements  11  of the group I. The light detecting element B converts the optical signals into an electrical signal and converts the electrical signal as a real-time electrical signal I real B  of the group II after receiving the optical signals emitted by the light emitting elements  11  of the group II. The light detecting element C converts the optical signals into an electrical signal and converts the electrical signal as a real-time electrical signal I real C  of the group III after receiving the optical signals emitted by the light emitting elements  11  of the group III. The light detecting element D converts the optical signals into an electrical signal and converts the electrical signal as a real-time electrical signal I real D  of the group IV after receiving the optical signals emitted by the light emitting elements  11  of the group IV. Then, the processor  805  adjusts the working current of the light emitting element  11  of the group I based on a comparing result between the I real A  and the I calibration A , adjusts the working current of the light emitting element  11  of the group II based on a comparing result between the I real B  and the I calibration B , adjusts the working current of the light emitting element  11  of the group III based on a comparing result between the I real C  and the I calibration C , and adjusts the working current of the light emitting element  11  of the group IV based on a comparing result between the I real D  and the I calibration D . 
     It may be noted that, the above is merely taking the number of light-emitting element groups is four and the number of light detecting elements is four as an example. In other examples, the number of light-emitting element groups and the number of light detecting elements may also be other values, which are not limited here. 
     It may be understood that, due to different manufacturing processes of each light emitting element  11 , various light emitting elements  11  may have different electro-optical conversion efficiencies, and different electro-optical conversion efficiencies may also have different reduction amounts after each light emitting element  11  is used for a period. In a case that the multiple light emitting elements  11  in the light source  10  are not grouped, the optical signals emitted by all the light emitting elements  11  of the entire light emitter  100  are directly detected to determine one adjusted working current, and all the light emitting elements  11  are driven based on the adjusted working current, it may be caused that a part of the optical signals emitted by the light emitting element  11  are stronger, a part of the optical signals emitted by the light emitting element  11  are weaker, and the optical signals emitted by the entire light source  10  have a poor uniformity. In this case, the light emitted into the target space is not the uniform surface light, but the light in some areas is stronger, and the light in some areas is weak, such that depth information of different areas in an entire depth image has different obtaining accuracies, and a quality of the obtained depth image is affected. 
     With the method according to embodiments of the disclosure, the multiple light emitting elements  11  are divided into the multiple light emitting element groups, and the calibration signal corresponding to each light-emitting element group is calibrated. In this way, the driving current of the light emitting elements  11  in the light-emitting element group corresponding to the calibration signal may be adjusted based on the calibration signal in the subsequent using procedure. The uniformity of the optical signals emitted by the light emitter  100  may be improved. The quality of the obtained depth image may be further improved. 
     Please refer to  FIG. 2 ,  FIG. 10  and  FIG. 11  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting element group. The controlling the light source to emit the optical signals at the predetermined working current at block  02  includes the following. 
     At block  022 , light emitting elements in the multiple light-emitting element groups are controlled to respectively emit the optical signals at different times. 
     The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals at block  03  includes the following. 
     At block  036 , the multiple light detecting elements are controlled to be turned on sequentially, and each light detecting element is turned on in response to turning on of the corresponding light-emitting element group, and each turned on light detecting element is controlled to receive the optical signals emitted by the light emitting elements in the turned on light-emitting element group, and to convert the optical signals into an electrical signal as the calibration electrical signal corresponding to the light-emitting element group. 
     Please refer to  FIG. 1 ,  FIG. 2 ,  FIG. 10  and  FIG. 11  together. In some implementations, the actions at blocks  022  and  036  both may be implemented by the calibration controller  806 . In other words, the calibration controller  806  may also be configured to control the light emitting elements  11  in the multiple light-emitting element groups to respectively emit the optical signals at different times; and to control the multiple the light detecting elements to be turned on sequentially, and each light detecting element is turned on in response to turning on of the corresponding light-emitting element group, and control each turned on light detecting element to receive the optical signals emitted by the light emitting elements in the turned on light-emitting element group, and to convert the optical signals into the electrical signal as the calibration electrical signal corresponding to the light-emitting element group. 
     In detail, please refer to  FIG. 10  again. assumed that the light-emitting element groups in the light emitter  100  includes groups I, II, III, and IV, each light-emitting element group includes multiple light emitting elements  11 , and each light-emitting element group may be controlled independently. The light detector  63  includes four light detecting elements, i.e., a light detecting element A, a light detecting element B, a light detecting element C, and a light detecting element D. The light detecting element A is disposed at a center position of a light emitting area where the group I is located. The group I corresponds to the light detecting element A. The light detecting element A may receive optical signals emitted by light emitting elements  11  of the group I. The light detecting element B is disposed at a center position of a light emitting area where the group II is located. The group II corresponds to the light detecting element B. The light detecting element B may receive optical signals emitted by light emitting elements  11  of the group II. The light detecting element C is disposed at a center position of a light emitting area where the group III is located. The group III corresponds to the light detecting element C. The light detecting element C may receive optical signals emitted by light emitting elements  11  of the group III. The light detecting element D is disposed at a center position of a light emitting area where the group IV is located. The group IV corresponds to the light detecting element D. The light detecting element D may receive optical signals emitted by light emitting elements  11  of the group IV. 
     In the calibration procedure, the calibration controller  806  controls all the light emitting elements  11  in the groups I, all the light emitting elements  11  in the groups II, all the light emitting elements  11  in the groups III and all the light emitting elements  11  in the groups IV to respectively emit light at different times, and controls the light detecting elements A, B, C and D to be turned on sequentially. In detail, for example, all the light emitting elements  11  in the group I are simultaneously turned on to emit the light, and the light detecting element A is controlled to be turned on at the same time. The light detecting element A detects the optical signals emitted by the light emitting elements  11  in the group I and converts the optical signals into an electrical signal, and the calibration controller  806  takes the electrical signal as a calibration electrical signal I calibration A  of the group I. Then, the calibration controller  806  turns off the light emitting elements  11  in the group I and the light detecting element A, turns on all the light emitting elements  11  in the group II to emit light at the same time, and controls the light detecting element B to be turned on. The light detecting element B detects the optical signals emitted by light emitting elements  11  in the group II and converts the optical signals into an electrical signal, and the calibration controller  806  takes the electrical signal as a calibration electrical signal I calibration B  of the group II. Then, the calibration controller  806  turns off the light emitting elements  11  in the group II and the light detecting element B, turns on all the light emitting elements  11  in the group III to emit light at the same time, and controls the light detecting element C to be turned on. The light detecting element C detects the optical signals emitted by the light emitting elements  11  in the group III and converts the optical signals into an electrical signal, and the calibration controller  806  takes the electrical signal as a calibration electrical signal I calibration C  of the group III. Then, the calibration controller  806  turns off the light emitting elements  11  in the group III and the light detecting elements C, turns on all the light emitting elements  11  in the group IV to emit light at the same time, and controls the light detecting element D to be turned on. The light detecting element D detects the optical signals emitted by the light emitting elements  11  in the group IV, and converts the optical signals into an electrical signal, and the calibration controller  806  takes the electrical signal as a calibration electrical signal I calibration D  of the group IV. Finally, the calibration controller  806  controls the light emitting elements  11  in the group IV and the light detecting element D to be turned off. 
     In the subsequent adjustment for the working current of the light source  10  of the time-of-flight module  300 , the processor  805  may respectively obtain real-time electrical signals I real A  corresponding to the group I, real-time electrical signals I real B  corresponding to the group II, real-time electrical signals I real C  corresponding to the group III and real-time electrical signals I real D  Corresponding to the group IV based on a flow of turning on the light emitting elements  11  in the groups I, II, III and IV and a flow of turning on the light detecting elements A, B, C and D. Finally, the processor  805  determines the working current of the light emitting element  11  of the group I based on a comparing result between the I real A  and the I calibration A , determines the working current of the light emitting element  11  of the group II based on a comparing result between the I real B  and the I calibration B , determines the working current of the light emitting element  11  of the group III based on a comparing result between the I real C  and the I calibration C , and determines the working current of the light emitting element  11  of the group IV based on a comparing result between the I real D  and the I calibration D . The processor  805  controls the light emitting elements  11  in the groups I, II, III and IV to simultaneously emit the optical signals based on the four adjusted working currents after the processor  805  determines the four adjusted working currents of the light emitting elements  11  in the corresponding groups I, II, III and IV based on the four comparing results. 
     It may be noted that, the above merely takes that the number of light-emitting element groups is four and the number of light detecting elements is four as an example. In other examples, the number of light-emitting element groups and the number of light detecting elements may also be other values, which are not limited here. 
     It may be understood that, when the light emitting elements in the four groups are simultaneously controlled to emit the light, the light detecting element A may receive the optical signals emitted by the light emitting elements  11  of the groups II, III and IV in addition to the optical signals emitted by the light emitting elements  11  of group I, and such situation also exits in the light detecting elements B, C and D. Therefore, the finally obtained calibration electrical signals I real A , I real B , I real C  and I real D  have low accuracy. In this implementation, the light emitting elements  11  in the four light-emitting element groups are sequentially turned on to emit the optical signals, so each light detecting element receives only the optical signals emitted by the light emitting elements  11  in the light-emitting element group corresponding to the light detecting element each time, and the finally obtained calibration electrical signal is more accurate. In the subsequent using procedure, the more accurate calibration electrical signal is taken as an adjustment reference of the working current, and the accuracy of the adjusted working current may also be improved. 
     Please refer to  FIG. 2 ,  FIG. 10  and  FIG. 12  together. In some implementations, the light emitter  100  includes multiple light emitting elements  11 . The multiple light emitting elements  11  are divided into multiple light-emitting element groups. The light detector  63  includes multiple light detecting elements each corresponding to each light-emitting element group. The controlling the light source  10  to emit the optical signals at the predetermined working current at block  02  includes the following. 
     At block  023 , light emitting elements  11  in the multiple light-emitting element groups are controlled to respectively emit the optical signals at different times. 
     The controlling the light detector  63  to receive the optical signals reflected by the optical element to form the calibration electrical signals at block  03  includes the following. 
     At block  037 , the multiple light detecting elements are controlled to be turned on simultaneously and to sequentially receive the optical signals each group emitted by the light emitting elements  11  in the turned on light-emitting element group, and to convert the optical signals into multiple electrical signals. 
     At block  038 : the calibration electrical signal corresponding to each light-emitting element group is obtained based on the multiple electrical signals each corresponding to each light-emitting element group and a weight corresponding to each electrical signal. 
     Please refer to  FIG. 1 ,  FIG. 2 ,  FIG. 10  and  FIG. 11  together. In some implementations, the actions at blocks  023 ,  037  and  038  both may be implemented by the calibration controller  806 . In other words, the calibration controller  806  may also be configured to: control light emitting elements  11  in the multiple light-emitting element groups to respectively emit the optical signals at different times; control the multiple light detecting elements to be turned on simultaneously and to sequentially receive the optical signals each group emitted by the light emitting elements  11  in the turned on light-emitting element group, and to convert the optical signals into the multiple electrical signals; and obtain the calibration electrical signal corresponding to each light-emitting element group based on the multiple electrical signals each corresponding to each light-emitting element group and the weight corresponding to each electrical signal. 
     In detail, please refer to  FIG. 10  again. assumed that the light-emitting element groups in the light emitter  100  includes groups I, II, III, and IV, each light-emitting element group includes multiple light emitting elements  11 , and each light-emitting element group may be controlled independently. The light detector  63  includes four light detecting elements, i.e., a light detecting element A, a light detecting element B, a light detecting element C, and a light detecting element D. The light detecting element A is disposed at a center position of a light emitting area where the group I is located. The group I corresponds to the light detecting element A. The light detecting element A may receive optical signals emitted by light emitting elements  11  of the group I. The light detecting element B is disposed at a center position of a light emitting area where the group II is located. The group II corresponds to the light detecting element B. The light detecting element B may receive optical signals emitted by light emitting elements  11  of the group II. The light detecting element C is disposed at a center position of a light emitting area where the group III is located. The group III corresponds to the light detecting element C. The light detecting element C may receive optical signals emitted by light emitting elements  11  of the group III. The light detecting element D is disposed at a center position of a light emitting area where the group IV is located. The group IV corresponds to the light detecting element D. The light detecting element D may receive optical signals emitted by light emitting elements  11  of the group IV. 
     In the calibration procedure, the calibration controller  806  controls all the light emitting elements  11  in the groups I, all the light emitting elements  11  in the groups II, all the light emitting elements  11  in the groups III and all the light emitting elements  11  in the groups IV to respectively emit light at different times, and controls the light detecting elements A, B, C and D to be turned on simultaneously to receive the optical signals emitted by the light emitting elements  11  in the turned-on light-emitting element group, in a progress of controlling the light emitting elements  11  in each light-emitting element group to emit light. In detail, for example, first, all the light emitting elements  11  in the group I are turned on simultaneously to emit light, the light detecting elements A-D are turned on simultaneously, and the light detecting elements A-D each receives the optical signals emitted by the light emitting elements  11  in the group I. Then, the calibration controller  806  turns off the light emitting elements  11  in the group I and the light detecting elements A-D, turns on all the light emitting elements  11  in the group II to emit light, and simultaneously turns on the light detecting elements A-D again. The light detecting elements A-D each receives the optical signals emitted by the light emitting elements  11  in the group II. After, the calibration controller  806  turns off the light emitting elements  11  in the group II and the light detecting elements A-D, turns on all the light emitting elements  11  in the group III to emit light, and simultaneously turns on the light detecting elements A-D again. The light detecting elements A-D each receives the optical signals emitted by all the light emitting elements  11  in the group III. Next, the calibration controller  806  turns off the light emitting elements  11  in the group III and the light detecting elements A-D, turns on all the light emitting elements  11  in the group IV to emit light, and simultaneously turns on the light detecting elements A-D again. The light detecting elements A-D each receives the optical signals emitted by the light emitting elements  11  in the group IV. Finally, the calibration controller  806  turns off the light emitting elements  11  in the group IV and the light detecting elements A-D. The light detecting element may correspondingly output four electrical signals, when one light-emitting element group is turned on each time. Taking the group I as an example, when the light emitting elements II in the group I are turned on, the light detecting elements A-D may correspondingly output four electrical signals I IA , I IB , I IC , and I ID . The calibration controller  806  first determines weights W A , W B , W C , W D  respectively corresponding to the electrical signals I IA , I IB , I IC , and I ID  based on distances between the light detecting elements A-D and the group I. A calculation way for a final calibration electrical signal I calibration A  is: I calibration A =I IA ×W A +I IB ×W B +I IC ×W C +I ID ×W D . Based on the same principle, the electrical signals I IB , I IC , and I ID  may be calculated. 
     In the subsequent adjustment for the working current of the light source  10  of the time-of-flight module  300 , the processor  805  may respectively obtain real-time electrical signals I real A  corresponding to the group I, real-time electrical signals I real B  corresponding to the group II, real-time electrical signals I real C  corresponding to the group III and real-time electrical signals I real D  corresponding to the group IV based on a flow of turning on the light emitting elements  11  in the groups I, II, III and IV in the calibration procedure, a flow of turning on the light detecting elements A, B, C and D, and a method for calculating the calibration signal corresponding to each light-emitting element group. Finally, the processor  805  determines the working current of the light emitting element  11  of the group I based on a comparing result between the I real A  and the I calibration A , determines the working current of the light emitting element  11  of the group II based on a comparing result between the I real B  and the I calibration B , determines the working current of the light emitting element  11  of the group III based on a comparing result between the I real C  and the I calibration C , and determines the working current of the light emitting element  11  of the group IV based on a comparing result between the I real D  and the I calibration D . The processor  805  controls the light emitting elements  11  in the groups I, II, III and IV to simultaneously emit the optical signals based on the four adjusted working currents after the processor  805  determines the four adjusted working currents of the light emitting elements  11  in the corresponding groups I, II, III and IV based on the four comparing results. 
     It may be noted that, the above merely takes that the number of light-emitting element groups is four and the number of light detecting elements is four as an example. In other examples, the number of light-emitting element groups and the number of light detecting elements may also be other values, which are not limited here. 
     It may be understood that, comparing with only turning on one light detecting element to detect the optical signals emitted by the light emitting elements  11  in the turned on light-emitting element group, more optical signals emitted by the light emitting elements  11  may be received by the multiple light detecting elements turned on simultaneously when the light-emitting element groups are sequentially turned on to determine the calibration electrical signals in the calibration procedure, thereby further improving the accuracy of the calibration electrical signals. In the subsequent using, the accuracy of the adjusted working current may also be improved by taking a more accurate calibration electrical signal as an adjustment reference of the working current. 
     In the description of the above implementations, each of the light detecting elements is located at the central position of the light emitting area of each light emitting element group. In other implementations, each light detecting element is located at a position adjacent to the corresponding light-emitting element group. For example, as illustrated in  FIG. 13 , the light detecting element A is located at a position adjacent to a top corner of the group I. As illustrated in  FIG. 14 , the light detecting element A is located at a position adjacent to a boundary of the group I. 
     Please refer to  FIG. 1  and  FIG. 15  together. In the electronic device  800  according to implementations of the disclosure, the housing  801  may be used as a mounting carrier for functional elements of the electronic device  800 . The housing  801  may provide protections against dust, drop, water and the like for the functional elements. The functional elements may be the display screen  802 , a visible light camera  400 , a telephone receiver and the like. In implementations of the disclosure, the housing  801  includes a main body  803  and a movable bracket  804 . The movable bracket  804  may move relatively to the main body  803  under driving of a driving device. For example, the movable bracket  804  may slide relatively to the main body  803  to enter the main body  803  (as illustrated in  FIG. 15 ) or slide out from the main body  803  (as illustrated in  FIG. 1 ). A part of the functional elements (such as the display screen  802 ) may be disposed on the main body  803 , and another part of the functional components (such as the time-of-flight module  300 , the visible light camera  400 , and the telephone receiver) may be disposed on the movable bracket  804 . A movement of the movable bracket  804  may drive the another part of the functional elements to be retracted into the main body  803  or be protruded from the main body  803 .  FIG. 1  and  FIG. 15  are only examples of a detailed form of the housing  801 , which may not be understood as a limitation of the housing  801  of the disclosure. 
     The time-of-flight module  300  is disposed on the housing  801 . In the specific implementation of the disclosure, the time-of-flight module  300  is disposed on the movable bracket  804 . The user may trigger the movable bracket  804  to slide out of the main body  803  to drive the time-of-flight module  300  out of the main body  803  when the time-of-flight module  300  is desired to use. The user may trigger the movable bracket  804  to slide into the main body  803  to drive the time-of-flight module  300  to retract into the main body  803  when the time-of-flight module  300  is not desired to use. 
     Please refer to  FIG. 16  to  FIG. 18 , the time-of-flight module  300  includes a first substrate assembly  71 , a cushion  72 , a light emitter  100  and a light receiver  200 . The first substrate assembly  71  includes a first substrate  711  and a flexible circuit board  712  coupled to each other. The cushion  72  is disposed on the first substrate  711 . The light emitter  100  is disposed on the cushion  72 . The flexible circuit board  712  is bent. One end of the flexible circuit board  712  is coupled to the first substrate  711 , and the other end is coupled to the light emitter  100 . The light receiver  200  is disposed on the first substrate  711 . The light receiver  200  includes an outer housing  741  and an optical device  742  disposed on the outer housing  741 . The outer housing  741  and the cushion  72  are coupled as one body. 
     In detail, the first substrate assembly  71  includes the first substrate  711  and the flexible circuit board  712 . The first substrate  711  may be a printed circuit board or a flexible circuit board. The first substrate  711  may be laid with a control line of the time-of-flight module  300 . One end of the flexible circuit board  712  may be coupled to the first substrate  711 , and the other end of the flexible circuit board  712  is coupled to a circuit board  50  (illustrated in  FIG. 18 ). The flexible circuit board  712  may be bent at a certain angle, such that relative positions of the components connected to the two ends of the flexible circuit board  712  may have more choices. 
     The cushion  72  is disposed on the first substrate  711 . In an example, the cushion  72  is contacted with the first substrate  711  and carried on the first substrate  711 . In detail, the cushion  72  may be combined with the first substrate  711  by means of gluing or the like. A material of the cushion  72  may be metal, plastic, or the like. In implementations of the disclosure, a surface of the cushion  72  which is combined with the first substrate  711  may be a flat surface, and the surface of the cushion  72  opposite to the combined surface may also be a flat surface, such that the light emitter  100  has a better stability when disposed on the cushion  72 . 
     The light receiver  200  is disposed on the first substrate  711 . A contact surface of the light receiver  200  and the first substrate  711  is substantially flush with a contact surface of the cushion  72  and the first substrate  711  (that is, installation starting points of the light receiver  200  and the first substrate  711  are at on a same plane). In detail, the light receiver  200  includes the outer housing  741  and the optical device  742 . The outer housing  741  is disposed on the first substrate  711 . The optical device  742  is disposed on the outer housing  741 . The outer housing  741  may be a lens holder and a lens barrel of the light receiver  200 . The optical device  742  may be an element such as a lens disposed within the outer housing  741 . Further, the light receiver  200  further includes a photosensitive chip (not illustrated). Optical signals reflected by a person or an object in the target space is irradiated into the photosensitive chip after passing through the optical device  742 , and the photosensitive chip generates a response to the optical signal. In implementations of the disclosure, the outer housing  741  and the cushion  72  are coupled as a whole. In detail, the outer housing  741  and the cushion  72  may be integrally formed; or the outer housing  741  and the cushion  72  are made of different materials and integrally formed in a way such as a two-color injection molding. The outer housing  741  and the cushion  72  may also be formed separately, and formed into a matching structure. When the time-of-flight module  300  is assembled, first one of the outer housing  741  and the cushion  72  may be disposed on the first substrate  711 , and then the other one is disposed on the first substrate  711 , which are connected as a whole. 
     In this way, the light emitter  100  is disposed on the cushion  72 . The cushion  72  may increase height of the light emitter  100 , thereby increasing the height of a surface where the light emitter  100  emits the optical signal, and the optical signals emitted by the light emitter  100  are not easily shielded by the light receiver  200 , such that the optical signal may be completely irradiated on a measured object in the target space. 
     Please refer to  FIG. 2 , the light receiver  100  includes the light source  10 , the diffuser  20 , the lens barrel  30 , the protective cover  40 , the circuit board  50 , the driver  61 , and the light detector  63 . 
     The lens barrel  30  includes an annular lens-barrel sidewall  33 . The annular lens-barrel sidewall  33  encloses a receiving cavity  62 . The lens-barrel sidewall  33  includes an inner surface  331  located within the receiving cavity  62  and an outer surface  332  opposite to the inner surface. The lens-barrel sidewall  33  includes a first surface  31  and a second surface  32  opposite to each other. The receiving cavity  62  penetrates through the first surface  31  and the second surface  32 . The first surface  31  is recessed toward the second surface  32  to form a mounting groove  34  communicated with the receiving cavity  62 . A bottom surface  35  of the mounting groove  34  is located on a side of the mounting groove  34  away from the first surface  31 . An outer surface  332  of the lens-barrel sidewall  33  has a circular cross section at one end of the first face  31 , and the outer surface  332  of the lens-barrel sidewall  33  forms an external thread at one end of the first face  31 . 
     The circuit board  50  is disposed on the second surface  32  of the lens barrel  30  and encloses one end of the receiving cavity  62 . The circuit board  50  may be a flexible printed circuit board or a printed circuit board. 
     The light source  10  is carried on the circuit board  50  and accommodated in the receiving cavity  62 . The light source  10  is used to emit optical signals toward the first surface  31  (mounting groove  34 ) side of the lens barrel  30 . The light source  10  may be a vertical-cavity surface laser (VCSEL). Height of the vertical cavity surface emitter laser is small, and the vertical cavity surface emitter is taken as the light source  10 , which facilitates to reduce the height of the light emitter  100  and facilitates the light emitter  100  to be integrated into an electronic device  800  such as a mobile phone that has a high requirement on a body thickness. 
     The driver  61  is carried on the circuit board  50  and electrically connected to the light source  10 . In detail, the driver  61  may receive an input signal modulated by the processor  805  or the calibration controller  806 , convert the input signal into a constant current source and then transmit the constant current source to the light source  10 , such that the light source  10  emits the optical signals toward the first surface  31  of the lens barrel  30  under action of the constant current source. In this implementation, the driver  61  is disposed outside the lens barrel  30 . In other implementations, the driver  61  may be disposed within the lens barrel  30  and carried on the circuit board  50 . 
     The diffuser  20  is disposed (carried) in the mounting groove  34  and collides with the mounting groove  34 . The diffuser  20  is configured to diffuse the optical signals passing through the diffuser  20 . That is, the optical signals may pass through the diffuser  20  and be diffused by the diffuser  20  or projected out of the lens barrel  30  when the light source  10  emits the optical signal toward the first surface  31  of the lens barrel  30 . 
     The protective cover  40  includes a top wall  41  and a protective sidewall  42  extending from one side of the top wall  41 . A center of the top wall  41  is disposed with a light emitting hole  401 . The light emitting hole  401  is disposed with a light emitting plate. The protective sidewall  42  is disposed around the top wall  41  and the light emitting hole  401 . The mounting cavity  43  are enclosed by the top wall  41  and the protective sidewall  42  together, and the light emitting hole  401  communicates with the mounting cavity  43 . A cross section of the inner surface of the protective sidewall  42  is circular, and internal threads are formed on the inner surface of the protective sidewall  42 . The inner thread of the protective sidewall  42  is screwed with the outer thread of the lens barrel  30  to mount the protective cover  40  on the lens barrel  30 . The collision between the top wall  41  and the diffuser  20  causes the diffuser  20  to be clamped between the top wall  41  and the bottom surface  35  of the mounting groove  34 . 
     In this way, the diffuser  20  is disposed in the mounting groove  34  by opening the mounting groove  34  on the lens barrel  30 , and the diffuser  20  is clamped between the protective cover  40  and the bottom surface  35  of the mounting groove  34  by disposing the protective cover  40  on the lens barrel  30 , such that the diffuser  20  is fixed on the lens barrel  30 . In this way, the diffuser  20  is fixed on the lens barrel  30  without glue, which may prevent gas glue from diffusing and solidifying on the surface of the diffuser  20  after the glue is volatilized into gaseous state, and affecting a microstructure of the diffuser  20 . The diffuser  20  may also be prevented from falling off the lens barrel  30  when an adhesive force of the glue between the diffuser  20  and the lens barrel  30  decreases due to aging. 
     In the description of the disclosure, reference throughout this specification to “an embodiment,” “some embodiments,” “an example,” “a specific example,” or “some examples,” means that a particular feature, structure, material or feature described in connection with the embodiment or example is included in at least one embodiment or example of the disclosure. The appearances of the above phrases throughout this specification are not necessarily referring to the same embodiment or example. Moreover, the particular feature, structure, material or feature described may be combined in any one or more embodiments or examples in a suitable manner. Furthermore, without contradicting each other, the skilled in the art may combine different embodiments or examples described in this specification and features of different embodiments or examples. 
     In addition, the terms “first” and “second” are only for description purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with “first” and “second” can include at least one of the features explicitly or implicitly. In addition, in the description of the disclosure, the term “a plurality of” means two or more, such as two and three, unless specified otherwise. 
     Any procedure or method described in a flow chart or described herein in other ways may be understood to include one or more modules, segments or portions of codes of executable instructions for achieving specific logical functions or steps in the procedure, and the scope of a preferred embodiment of the disclosure includes other implementations. The order of execution is different from that which is depicted or discussed, including executing functions in a substantially simultaneous manner or in an opposite order according to the related functions, which should be understood by those skilled in the art which embodiments of the disclosure belong to. 
     The logic and/or step described in other manners herein or shown in the flow chart, for example, a particular sequence table of executable instructions for realizing the logical function, may be specifically achieved in any computer readable medium to be used by the instruction execution system, device or equipment (such as the system based on computers, the system including processors or other systems capable of obtaining the instruction from the instruction execution system, device and equipment and executing the instruction), or to be used in combination with the instruction execution system, device and equipment. As to the specification, “the computer readable medium” may be any device adaptive for including, storing, communicating, propagating or transferring programs to be used by or in combination with the instruction execution system, device or equipment. More detailed examples of the computer readable medium include, but are not limited to: an electronic connection (an electronic device) with one or more wires, a portable computer enclosure (a magnetic device), a random access memory (RAM), a read only memory (ROM), an erasable programmable read-only memory (EPROM or a flash memory), an optical fiber device and a portable compact disk read-only memory (CDROM). In addition, the computer readable medium may even be a paper or other appropriate medium capable of printing programs thereon, this is because, for example, the paper or other appropriate medium may be optically scanned and then edited, decrypted or processed with other appropriate methods when necessary to obtain the programs in an electric manner, and then the programs may be stored in the computer memory. 
     It should be understood that each part of the disclosure may be realized by the hardware, software, firmware or their combination. In the above implementations, multiple steps or methods may be realized by the software or firmware stored in the memory and executed by the appropriate instruction execution system. For example, if it is realized by the hardware, likewise in another embodiment, the steps or methods may be realized by one or a combination of the following techniques known in the art: a discretely logic circuit having a logic gate circuit for realizing a logic function of a data signal, an application-specific integrated circuit having an appropriate combination logic gate circuit, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. 
     Those skilled in the art shall understand that all or parts of the steps in the above embodiment method may be achieved by commanding the related hardware with a program. The program may be stored in a computer readable storage medium, and the program includes one or a combination of the steps in the method embodiments when operated on a computer. 
     In addition, each function unit of each embodiment of the disclosure may be integrated in a processing module, or these units may be separate physical existence, or two or more units are integrated in a processing module. The integrated module may be realized in a form of hardware or in a form of software function modules. When the integrated module is realized in the form of software function module and is sold or used as a standalone product, the integrated module may be stored in a computer readable storage medium. 
     The storage medium mentioned above may be a read-only memory, a magnetic disk or CD, etc. Although embodiments of the disclosure have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the disclosure. The skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the disclosure.