Patent Publication Number: US-2022236391-A1

Title: Decoherent effect processing device, decoherent effect processing system, and method thereof

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Chinese Patent Application No. 201910473270.7, titled “DECOHERENT EFFECT PROCESSING DEVICE, DECOHERENT EFFECT PROCESSING SYSTEM, AND METHOD THEREOF”, filed on May 31, 2019 with the Chinese Patent Office, which is incorporated herein by reference in its entirety. 
     FIELD 
     The present disclosure relates to the field of laser radars, and in particular to a device for processing decoherence effect, a system for processing decoherence effect, and a method for processing decoherence effect. 
     BACKGROUND 
     With the development of science and technology, the use of laser for ranging has gradually entered people&#39;s lives. 
     In the conventional technology, a laser light emitted by a light source is reflected by a target object, and a returned signal light has low power due to long-distance transmission. Generally, the signal light reflected by the target object is loaded into a local light to obtain a coherent light having high power. The coherent light is incident on a receiving surface to output a current. A time when the current suddenly changes is determined as a time when the receiving surface receives the coherent light, and a distance between the light source and the target object is determined according to the time when the laser light is emitted and the time when the coherent light is received. 
     However, in the process of realizing the above solution in the conventional technology, it is found by the inventor that, after the coherent light is incident on the receiving surface, the current outputted by the receiving surface changes in a sine wave, resulting in a randomly distributed positive or negative polarity of the current of the output current of the pixel at different positions on the receiving surface. In this case, when summing the output current of each pixel to obtain the output current of the entire receiving surface, different pixels correspond to different polarities of the output current, so that the calculation result is distorted, which results in poor accuracy of laser ranging. 
     SUMMARY 
     An object of the present disclosure is to provide a device for processing decoherence effect processing, a system for processing decoherence effect, and a method for processing decoherence effect, to solve the problem of poor accuracy of laser ranging. 
     In order to achieve the above object, a device for processing decoherence effect is provided according to an embodiment of the present disclosure. The device includes: a signal acquisition module and a processing module. An output end of the signal acquisition module is connected to an input end of the processing module. The signal acquisition module is configured to acquire a coherent light and convert the coherent light into a first signal having a polarity. The processing module is configured to depolarize the first signal to obtain a correlation value of the first signal, where the correlation value is a value greater than 0. 
     Further, the processing module includes one of the following: a unidirectional conducting unit, a class B power amplifier, and a multiplier. 
     Further, the device further includes a conversion module. The conversion module is provided between the signal acquisition module and the processing module. The conversion module is configured to convert the first signal into a second signal. 
     Further, the processing module includes: a Gilbert unit having four input terminals and two output terminals. The four input terminals include a first input terminal, a second input terminal, a third input terminal and a fourth input terminal. The two output terminals include a first output terminal and a second output terminal. Both the first input terminal and the third input terminal of the Gilbert unit are connected with an output end of the conversion module to acquire the second signal. Both the second input terminal and the fourth input terminal of the Gilbert unit are connected to a reference signal input module to acquire a reference signal. The Gilbert unit is configured to: compare the second signal with the reference signal to obtain a relative difference, and determine a result of squaring the relative difference as the correlation value. A difference between a signal outputted from the first output terminal of the Gilbert unit and a signal outputted from the second output terminal of the Gilbert unit is the correlation value. 
     Further, the conversion module includes an amplifying circuit. One terminal of the amplifying circuit is connected to a signal input end, and the other terminal of the amplifying circuit is connected to the output end of the signal acquisition module. The amplifying circuit is configured to convert the first signal outputted by the signal acquisition module through a signal inputted from the signal input end, to obtain the amplified second signal. 
     Further, the amplifying circuit includes a common-gate amplifier. 
     Further, the common-gate amplifier includes a resistance unit and a first mos transistor. One end of the resistance unit is connected to the signal input end, and the other end of the resistance unit is connected to a drain of the first mos transistor. A source of the first mos transistor is connected to the output end of the signal acquisition module. 
     Further, the resistance unit includes: a second mos transistor, a second isolation element and a second capacitor. The signal input end is connected to one end of the second capacitor and a source of the second mos transistor. The other end of the second capacitor is connected to a gate of the second mos transistor and one end of the second isolation element. The other end of the second isolation element is connected to a drain of the second mos transistor and the drain of the first mos transistor. 
     Further, the reference signal input module includes: a first isolation element and a first capacitor. One end of the first capacitor is connected between the first isolation element and the processing module, and the other end of the first capacitor is grounded. The first capacitor is configured to: store charges corresponding to a third signal in a case that the first isolation element is conducting, where the third signal includes a signal into which the signal acquisition module converts a background light. The first isolation element is provided between the signal acquisition module and the processing module and is configured to control conducting or non-conducting between the signal acquisition module and the processing module, where in the case of conducting, the charges outputted by the signal acquisition module are transferred to the first capacitor, so that in the case of non-conducting, the signal in the case of conducting is inputted to the second input terminal and the fourth input terminal of the Gilbert unit. 
     A system for processing decoherence effect is further provided according to another embodiment of the present disclosure. The system includes: at least two devices for processing decoherence effect as described above, and a determining device. An input end of the determining device is connected to an output end of each of the devices for processing decoherence effect. The determining device is configured to add all correlation values to obtain a sum of the coherent light after decoherence. 
     Further, the system further includes a signal amplifying circuit. The signal amplifying circuit is provided between the determining device and the devices for processing decoherence effect. The signal amplifying circuit is configured to amplify the correlation value. 
     A method for processing decoherence effect is further provided according to another embodiment of the present disclosure. The method includes:
         acquiring a coherent light, and converting the coherent light into a first signal having a polarity; and   depolarizing the first signal to obtain a correlation value of the first signal, where the correlation value is a value greater than 0.       

     Further, before depolarizing the first signal to obtain the correlation value of the first signal, the method further includes: converting the first signal into a second signal. 
     Further, the process of depolarizing the first signal to obtain the correlation value of the first signal includes: comparing the second signal with a reference signal to obtain a relative difference, and determining a result of squaring the relative difference as the correlation value. 
     Further, the process of converting the first signal into the second signal includes: converting the first signal through a signal to obtain the amplified second signal. 
     Further, after depolarizing the first signal to obtain the correlation value of the first signal, the method further includes: adding all correlation values to obtain a sum of the coherent light after decoherence. 
     With the above technical solutions, a device for processing decoherence effect, a system for processing decoherence effect, and a method for processing decoherence effect are provided. The device includes a signal acquisition module and a processing module. An output end of the signal acquisition module is connected to an input end of the processing module. The signal acquisition module is configured to acquire a coherent light and convert the coherent light into a first signal having a polarity. The processing module is configured to depolarize the first signal to obtain a correlation value of the first signal, where the correlation value is a value greater than 0. In this way, the first signal is depolarized, so that the correlation value greater than 0 can be processed, avoiding serious distortion of the calculation result caused due to the first signal of different polarities, thereby improving the accuracy of laser ranging. 
     Other features and advantages of the present disclosure are described in detail in the following specific embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are given to provide a further understanding for the present disclosure and form a part of this specification. The accompanying drawings together with the following embodiments are used to explain the present disclosure and do not constitute a limitation to the present disclosure. In the accompanying drawings: 
         FIG. 1  is a schematic structural diagram showing a device for processing decoherence effect according to an embodiment of the present disclosure; 
         FIG. 2  is a schematic structural diagram showing a device for processing decoherence effect according to another embodiment of the present disclosure; 
         FIG. 3  is a schematic structural diagram showing a device for processing decoherence effect according to another embodiment of the present disclosure; 
         FIG. 4  is a schematic structural diagram showing a device for processing decoherence effect according to another embodiment of the present disclosure; 
         FIG. 5  is a schematic structural diagram showing a system for processing decoherence effect according to an embodiment of the present disclosure; 
         FIG. 6  is a schematic diagram showing a method for processing decoherence effect according to an embodiment of the present disclosure; and 
         FIG. 7  is a schematic diagram showing a method for processing decoherence effect according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Exemplary embodiments are described in detail hereafter, and examples thereof are shown in the accompanying drawings. In the following description related to the accompanying drawings, the same number in different drawings indicates the same or similar elements unless otherwise indicated. Implementations described in the following exemplary embodiments do not represent all implementations consistent with the present disclosure, and merely show examples of the device and the method consistent with some aspects of the present disclosure as detailed in the appended claims. 
       FIG. 1  is a schematic structural diagram showing a device for processing decoherence effect according to an embodiment of the present disclosure. As shown in  FIG. 1 , the device for processing decoherence effect includes: a signal acquisition module  11  and a processing module  12 . An output end of the signal acquisition module  11  is connected to an input end of the processing module  12 . 
     The signal acquisition module  11  is configured to acquire a coherent light and convert the coherent light into a first signal having a polarity. 
     The processing module  12  is configured to depolarize the first signal to obtain a correlation value of the first signal. The correlation value may be a value greater than 0. 
     The coherent light in this embodiment includes a light obtained by loading a signal light into a local light, where the signal light is formed by a target object reflecting a laser light emitted from a light source. 
     Specifically, after the light source emits the laser light to the target object, the signal light reflected back by the target object is generally loaded into the local light due to low power of the signal light, so as to obtain the coherent light. Further, the coherent light is outputted as a first signal varying in the form of a sine wave through the signal acquisition module  11 . That is, a first signal polarity outputted by the signal acquisition module  11  may be positive or negative. For example, the first signal may be an analog signal. The signal having the polarity is inputted to the processing module  12 . The first signal is depolarized by the processing module  12  to obtain the correlation value of the first signal, where the correlation value is a value greater than 0. The correlation value may be an absolute value of the first signal, or a value in proportion to the absolute value of the first signal. In addition, the correlation value may also be obtained by the following process. The first signal is controlled to pass through a resistor, to obtain a second signal when the first signal passes through the resistor. In this case, the correlation value may be an absolute value of the second signal, or a value in proportion to the absolute value of the second signal. The explanation of the correlation value herein is merely exemplary and is not limited thereto. 
     In this embodiment, the processing module  12  includes any one of the following: a unidirectional conducting unit, a class B power amplifier, and a multiplier. 
     Specifically, the unidirectional conducting unit is a circuit having the following characteristics. The first signal can only flow from an input end of the unidirectional conducting unit to an output end of the unidirectional conducting unit and cannot reversely flow from the output end of the unidirectional conducting unit to the input end of the unidirectional conducting unit. For example, the first signal of which the first signal polarity is positive can pass through the unidirectional conducting unit, and the first signal of which the first signal polarity is negative cannot pass through the unidirectional conducting unit, so that a correlation value outputted from the output end of the unidirectional conducting unit is the first signal whose polarity is positive. The unidirectional conducting unit may be implemented by a diode or a MOS transistor. 
     The class B power amplifier is an amplifying circuit that is conducting only in half a cycle. The class B power amplifier may be controlled to be conducting when the first signal varying in the form of a sine wave is positive and to be non-conducting when the first signal varying in the form of a sine wave is negative. For example, an input end of the class B power amplifier is connected to the output end of the signal acquisition module  11 . In this case, the first signal of which the first signal polarity is positive can pass through the class B power amplifier, and the first signal of which the first signal polarity is negative cannot pass through the class B power amplifier, so that a correlation value outputted from an output end of the class B power amplifier is the first signal whose polarity is positive. 
     An input end of the multiplier is connected to the output end of the signal acquisition module  11 . The first signal outputted by the signal acquisition module  11  may be squared to obtain the first signal whose polarity is positive, so that a correlation value outputted from an output end of the multiplier is the first signal whose polarity is positive. 
     In this embodiment, the signal acquisition module and the processing module are provided. The output end of the signal acquisition module is connected to the input end of the processing module. The signal acquisition module is configured to acquire the coherent light and convert the coherent light into the first signal having the polarity. The processing module is configured to depolarize the first signal to obtain the correlation value of the first signal, where the correlation value is a value greater than 0. In this way, the first signal is depolarized, so that the correlation value greater than 0 can be processed, avoiding serious distortion of the calculation result caused due to the first signal of different polarities, thereby improving the accuracy of laser ranging. 
       FIG. 2  is a schematic structural diagram showing a device for processing decoherence effect according to another embodiment of the present disclosure. As shown in  FIG. 2 , based on the above embodiments, the device for processing decoherence effect further includes a conversion module  13  provided between the signal acquisition module  11  and the processing module  12 . 
     The conversion module  13  is configured to convert the first signal into a second signal. 
     Specifically, the first signal is converted into the second signal by the conversion module  13 . The second signal obtained by the conversion of the conversion module  13  may be positive or negative. In this case, the processing module  12  processes the second signal to obtain the correlation value of the first signal, where the correlation value is a value greater than 0. For example, in this embodiment, the first signal may be a current, and the second signal may be a voltage. 
     The conversion module  13  may convert the first signal into the second signal in the following manners. 
     In a first manner, after the conversion module  13  obtains the first signal outputted by the signal acquisition module  11 , the conversion module  13  outputs the second signal. 
     In a second manner, after the conversion module  13  obtains the first signal outputted by the signal acquisition module  11 , the conversion module  13  outputs the second signal in the case of determining that the first signal is greater than a preset value. 
       FIG. 3  is a schematic structural diagram showing a device for processing decoherence effect according to another embodiment of the present disclosure. As shown in  FIG. 3 , based on the above embodiments, the processing module  12  in the device for processing decoherence effect may include a Gilbert unit  121 . 
     The Gilbert unit  121  has four input terminals and two output terminals. The four input terminals include a first input terminal  1201 , a second input terminal  1202 , a third input terminal  1203  and a fourth input terminal  1204 . The two output terminals include a first output terminal  1205  and a second output terminal  1206 . 
     Both the first input terminal  1201  and the third input terminal  1203  of the Gilbert unit  121  are connected to an output end of the conversion module  13  to acquire the second signal. 
     Both the second input terminal  1202  and the fourth input terminal  1204  of the Gilbert unit  121  are connected to a reference signal input module  131  to acquire a reference signal. 
     The Gilbert unit  121  is configured to: compare the second signal with the reference signal to obtain a relative difference, and determine a result of squaring the relative difference as the correlation value. 
     A difference between a signal outputted from the first output terminal  1205  of the Gilbert unit  121  and a signal outputted from the second output terminal  1206  of the Gilbert unit  121  is the correlation value. 
     Specifically, the second signal acquired by the first input terminal  1201  and the third input terminal  1203  of the Gilbert unit  121  is formed by the following process. The coherent processing is performed on a background light, a signal light reflected back by the target object, and a local light to obtain a coherent light, and the coherent light is processed by the signal acquisition module  11  to generate a first signal, which may be, for example, a current. The first signal is processed by the conversion module  13  to obtain a second signal, which may be, for example, a voltage. 
     The reference signal is formed by the following process. The coherent processing is performed on a background light and a local light to obtain a coherent light, and the coherent light is processed by the signal acquisition module  11  to generate a first signal, which may be, for example, a current. The first signal is processed by the conversion module  13  to obtain a second signal, which may be, for example, a voltage. In addition, a bias signal may be set for the processing module  12  to obtain a second signal equal to the reference signal, i.e., a bias voltage equal to the reference signal that is the reference voltage. 
     Based on the above embodiments, the conversion module  13  includes an amplifying circuit. 
     One terminal of the amplifying circuit is connected to a signal input end, and the other terminal of the amplifying circuit is connected to the output end of the signal acquisition module  11 . The amplifying circuit is configured to convert the first signal outputted by the signal acquisition module  11  through a signal inputted from the signal input end, to obtain the amplified second signal. 
     Based on the above embodiments, the amplifying circuit in the device for processing decoherence effect includes: a common-gate amplifier  141 . 
     Specifically, the common-gate amplifier  141  includes a resistance unit  1411  and a first mos transistor  1422 . 
     One end of the resistance unit  1411  is connected to the signal input end, the other end of the resistance unit  1411  is connected to a drain of the first mos transistor  1422 , and a source of the first mos transistor  1422  is connected to the output end of the signal acquisition module  11 . 
     In this embodiment, in a case that the first signal outputted from the output end of the signal acquisition module  11  is greater than a preset signal value, the first signal can be outputted through the drain of the first mos transistor  1422 . That is, the first mos transistor  1422  is equivalent to a unidirectional conducting impedance. The first mos transistor  1422  can be conducing only when the first signal outputted from the output end is large enough. Further, the first signal can only be transmitted from the signal acquisition module  11  to the resistance unit  1411  through the first mos transistor  1422 , and the first signal cannot be reversely transmitted from the resistance unit  1411  to the signal acquisition module  11 . 
     Specifically, in the case that the first signal outputted from the output end of the signal acquisition module  11  is greater than the preset signal value, the first signal can be outputted through the drain of the first mos transistor  1422 , and the first signal is processed by means of the output signal of the signal input end to obtain an amplified second signal. 
     Further, based on the above embodiments, the resistance unit  1411  includes: a second mos transistor  14111 , a second isolation element  14112 , and a second capacitor  14113 . 
     The signal input end is connected to one end of the second capacitor and a source of the second mos transistor. The other end of the second capacitor is connected to a gate of the second mos transistor and one end of the second isolation element. The other end of the second isolation element is connected to a drain of the second mos transistor and the drain of the first mos transistor  1422 . 
       FIG. 4  is a schematic structural diagram showing a device for processing decoherence effect according to another embodiment of the present disclosure. As shown in  FIG. 4 , based on the above embodiments, the reference signal input module  131  includes: a first isolation element  1311  and a first capacitor  1312 . 
     One end of the first capacitor  1312  is connected between the first isolation element  1311  and the processing module  12 , and the other end of the first capacitor  1312  is grounded. The first capacitor  1312  is configured to: store charges corresponding to a third signal in a case that the first isolation element  1311  is conducting. The third signal includes a signal into which the signal acquisition module  11  converts a background light. 
     The first isolation element  1311  is provided between the signal acquisition module  11  and the processing module  12 , and is configured to control conducting or non-conducting between the signal acquisition module  11  and the processing module  12 . In the case of conducting, the charges outputted by the signal acquisition module  11  are transferred to the first capacitor  1312 , so that in the case of non-conducting, the signal in the case of conducting is inputted to the second input terminal  1202  and the fourth input terminal  1204  of the Gilbert cell  121 . 
       FIG. 5  is a schematic structural diagram showing a system for processing decoherence effect according to an embodiment of the present disclosure. As shown in  FIG. 5 , the system for processing decoherence effect includes: at least two devices  501  for processing decoherence effect shown in any one of  FIG. 1  to  FIG. 4 , and a determining device  502 . 
     An input end of the determining device  502  is connected to an output end of each of the devices for processing decoherence effect. The determining device is configured to add all correlation values to obtain a sum of the coherent light after decoherence. 
     Further, the determining device is further configured to compare the sum with a preset value to determine a time when the signal acquisition module acquires the coherent light. 
     Specifically, each pixel in a receiving surface for laser ranging may be provided with at least one device  501  for processing decoherence effect. After the coherent light passes through the device  501  for processing decoherence effect, the obtained correlation value is greater than 0. The correlation values respectively outputted by the devices for processing decoherence effect in pixels are added to obtain a correlation value of a sum of values of the first signal in all the pixels, i.e., the sum of the correlation values. Since the correlation value is greater than 0, serious distortion of the calculation results caused due to the first signal of different polarities can be avoided. Further, the sum of the correlation values respectively outputted by the devices for processing decoherence effect in the pixels is compared with the preset value. If the sum of all the correlation values is greater than or equal to the preset value, it can be determined that the light received by the receiving surface has a sudden change, and a time when the light received by the receiving surface changes suddenly is determined as the time when the signal acquisition module acquires the coherent light. A distance between the target object and the light source is determined according to the time when the light is emitted from the light source, the time when the signal acquisition module acquires the coherent light, and the light speed. In this way, the correlation value outputted by each device for processing decoherence effect is a value greater than 0, avoiding serious distortion of the calculation result caused due to the first signal of different polarities, thereby improving the accuracy of laser ranging. 
     Further, based on the above embodiments, the system for processing decoherence effect may further include: a signal amplifying circuit. 
     The signal amplifying circuit is provided between the determining device and the devices for processing decoherence effect. The signal amplifying circuit is configured to amplify the correlation value. 
     In this embodiment, by amplifying the correlation value, the correlation value can be increased, and the correlation value can be further improved, thereby further improving the accuracy of comparing the sum of the correlation values with the preset value. 
       FIG. 6  is a schematic diagram showing a method for processing decoherence effect according to an embodiment of the present disclosure. As shown in  FIG. 6 , the method for processing decoherence effect is based on the device for processing decoherence effect as shown in any one of  FIGS. 1 to 4 . The method includes the following steps  601  and  602 . 
     In step  601 , a coherent light is acquired, and the coherent light is converted into a first signal having a polarity. 
     In step  602 , the first signal is depolarized to obtain a correlation value of the first signal. 
     The correlation value in this embodiment is a value greater than 0. The coherent light includes a light obtained by loading a signal light into a local light, where the signal light is formed by a target object reflecting a laser light emitted from a light source. 
     Specifically, after the light source emits the laser light to the target object, the signal light reflected back by the target object is generally loaded into the local light due to low power of the signal light, so as to obtain the coherent light. Further, the coherent light is outputted as a first signal varying in the form of a sine wave through the signal acquisition module  11 . That is, a first signal polarity outputted by the signal acquisition module  11  may be positive or negative. For example, the first signal may be an analog signal. The signal having the polarity is inputted to the processing module  12 . The first signal is depolarized by the processing module  12  to obtain the correlation value of the first signal, where the correlation value is a value greater than 0. The correlation value may be an absolute value of the first signal, or a value in proportion to the absolute value of the first signal. In addition, the correlation value may also be obtained by the following process. The first signal is controlled to pass through a resistor, to obtain a second signal when the first signal passes through the resistor. In this case, the correlation value may be an absolute value of the second signal, or a value in proportion to the absolute value of the second signal. The explanation of the correlation value herein is merely exemplary and is not limited thereto. 
     In this embodiment, the signal acquisition module and the processing module  12  are provided. The output end of the signal acquisition module is connected to the input end of the processing module  12 . The signal acquisition module is configured to acquire the coherent light and convert the coherent light into the first signal having the polarity. The processing module  12  is configured to depolarize the first signal to obtain the correlation value of the first signal, where the correlation value is a value greater than 0. In this way, the first signal is depolarized, so that the correlation value greater than 0 can be summed or processed in another manner, avoiding serious distortion of the calculation result caused due to the first signal of different polarities, thereby improving the accuracy of laser ranging. 
     Based on the above embodiments, the method may further include: converting the first signal into a second signal. 
       FIG. 7  is a schematic diagram showing a method for processing decoherence effect according to another embodiment of the present disclosure. As shown in  FIG. 7 , the method for processing decoherence effect includes the following steps  701  to  703 . 
     In step  701 , a coherent light is acquired, and the coherent light is converted into a first signal having a polarity. 
     In step  702 , the first signal is converted into a second signal. 
     Specifically, the first signal is converted through a signal to obtain an amplified second signal. 
     In step  703 , the second signal is compared with a reference signal to obtain a relative difference, and a result of squaring the relative difference is determined as the correlation value. 
     In this embodiment, the first signal is depolarized, so that the correlation value greater than 0 can be summed or processed in another manner, avoiding serious distortion of the calculation result caused due to the first signal of different polarities, thereby improving the accuracy of laser ranging. 
     Further, after depolarizing the first signal to obtain the correlation value of the first signal, the method further includes:
         adding all correlation values to obtain a sum of the coherent light after decoherence.       

     It should further be noted that, technical features described in the above embodiments can be combined in any suitable manner in the absence of contradiction. Further, different implementations in the present disclosure can be combined in any manner without departing from the idea of the present disclosure. These combinations should be regarded as contents disclosed in the present disclosure. The present disclosure is not limited to structures described above. The scope of the present disclosure is only defined by the appended claims.