Patent Publication Number: US-2022214435-A1

Title: Distance measuring sensor, signal processing method, and distance measuring module

Description:
TECHNICAL FIELD 
     The present technology relates to a distance measuring sensor, a signal processing method, and a distance measuring module, and more particularly, to a distance measuring sensor, a signal processing method, and a distance measuring module that enable a detection process based on distance measurement data. 
     BACKGROUND ART 
     In recent years, with the progress of semiconductor technology, miniaturization of a distance measuring module that measures the distance to an object has advanced. Therefore, for example, installation of the distance measuring module on a mobile terminal such as a so-called smartphone, which is a small information processing device having a communication function, is realized. 
     Examples of a distance measuring method in the distance measuring module include an indirect time of flight (ToF) method and a structured light method. In the Indirect ToF method, light is emitted toward an object and the light reflected on a surface of the object is detected, and the distance to the object is calculated on the basis of a measurement value obtained by measuring a flight time of the light. In the structured light method, pattern light is emitted toward an object, and the distance to the object is calculated on the basis of an image obtained by imaging distortion of a pattern on a surface of the object. 
     A distance measuring sensor of the Indirect ToF method that adopts a back-illuminated structure in order to improve light receiving characteristics (See, for example, Patent Document 1.) has been proposed. 
     In some smartphones, a face authentication process of authenticating the face of a user is used, for example, to unlock the screen. In the preprocessing for performing the face authentication process, a detection process of detecting the user, such as whether the user is in front of the smartphone, is performed. This detection processing has been executed by an application processor of a smartphone on the basis of an output from a distance measuring sensor. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: International Publication No. 2018/135320 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, in order to reduce the amount of power required by a smartphone, it is required to perform part of the detection process by a distance measuring sensor. 
     The present technology has been made in view of such a situation, and enables a distance measuring sensor to execute a detection process based on distance measurement data. 
     Solution to Problems 
     A distance measuring sensor according to a first aspect of the present technology includes: a light receiving unit that receives reflected light obtained by reflection of irradiation light emitted from a predetermined light emitting source by an object; a depth calculation unit that calculates distance information to the object and luminance information from a signal obtained by the light receiving unit; and a detection processing unit that executes a predetermined detection process by using at least one of the distance information or the luminance information in accordance with a current operation mode selected from among a plurality of operation modes, and outputs a result of a detection process to an outside together with the distance information and the luminance information. 
     A signal processing method according to a second aspect of the present technology includes: by using a distance measuring sensor, calculating distance information to an object and luminance information from a signal obtained by receiving reflected light obtained by reflection of irradiation light emitted from a predetermined light emitting source by the object; and by using the distance measuring sensor, executing a predetermined detection process by using at least one of the distance information or the luminance information in accordance with a current operation mode selected from among a plurality of operation modes, and outputting a result of a detection process to an outside together with the distance information and the luminance information. 
     A distance measuring module according to a third aspect of the present technology includes: a light emitting unit that includes a predetermined light emitting source; and a distance measuring sensor, the distance measuring sensor including: a light receiving unit that receives reflected light obtained by reflection of irradiation light emitted from the predetermined light emitting source by an object; a depth calculation unit that calculates distance information to the object and luminance information from a signal obtained by the light receiving unit; and a detection processing unit that executes a predetermined detection process by using at least one of the distance information or the luminance information in accordance with a current operation mode selected from among a plurality of operation modes, and outputs a result of a detection process to an outside together with the distance information and the luminance information. 
     In the first to third aspects of the present technology, distance information to an object and luminance information are calculated from a signal obtained by receiving reflected light obtained by reflection of irradiation light emitted from a predetermined light emitting source by the object, a predetermined detection process is executed by using at least one of the distance information or the luminance information in accordance with a current operation mode selected from among a plurality of operation modes, and a result of a detection process is output to the outside together with the distance information and the luminance information. 
     The distance measuring sensor and the distance measuring module may be an independent device or a module incorporated in another device. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating a schematic configuration example of a smartphone as an electronic apparatus to which the present technology is applied. 
         FIG. 2  is a block diagram illustrating a detailed configuration example of a distance measuring module. 
         FIG. 3  is a diagram illustrating a detailed configuration example of a light receiving unit. 
         FIG. 4  is a diagram explaining operation of a pixel according to a 4-phase method. 
         FIG. 5  is a diagram explaining the 4-phase method. 
         FIG. 6  is a diagram explaining the 4-phase method. 
         FIG. 7  is a diagram explaining methods of calculating a depth value by using a 2-phase method and the 4-phase method. 
         FIG. 8  is a diagram explaining a specific detection process executed in each operation mode. 
         FIG. 9  is a diagram explaining a specific processing example of a proximity detection process. 
         FIG. 10  is a diagram explaining a specific processing example of a head portion detection process. 
         FIG. 11  is a diagram explaining a specific processing example of a face detection process. 
         FIG. 12  is a diagram explaining a specific processing example of a pupil detection process. 
         FIG. 13  is a flowchart explaining a depth measurement process in the case of an operation mode B. 
         FIG. 14  is a flowchart explaining a depth measurement process in the case of an operation mode D. 
         FIG. 15  is a diagram illustrating an effect of a distance measuring sensor to which the present technology is applied. 
         FIG. 16  is a block diagram illustrating an example of a schematic configuration of a vehicle control system. 
         FIG. 17  is an explanatory view illustrating an example of installation locations of an outside-vehicle information detecting unit and imaging units. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Hereinafter, embodiments for implementing the present technology (hereinafter, referred to as embodiments) will be described. Note that the description will be given in the following order. 
     1. Configuration Example of Smartphone 
     2. Schematic Configuration Example of Distance Measuring Module 
     3. Distance Measurement Operation of Distance Measuring Sensor by Indirect ToF Method 
     4. Detection Process According to Operation Mode 
     5. Effect of Distance Measuring Sensor 
     6. Example of Application to Moving Object 
     &lt;1. Configuration Example of Smartphone&gt; 
       FIG. 1  is a block diagram illustrating a schematic configuration example of a smartphone as an electronic apparatus to which the present technology is applied. 
     As illustrated in  FIG. 1 , a smartphone  1  is configured by connecting a distance measuring module  11 , an imaging device  12 , a display  13 , a communication module  14 , a sensor unit  15 , a speaker  16 , a microphone  17 , an operating button  18 , a sensor hub  19 , an application processor (AP)  20 , and a power supply unit  21  via a bus  22 . 
     The distance measuring module  11  is arranged on a front surface of the smartphone  1 , and performs distance measurement for the user of the smartphone  1 . Thus, the distance measuring module  11  measures distance information (measures a distance) to a target such as the face, a hand, a finger, or the like of the user and outputs the distance information. 
     The imaging device  12  is arranged on the front surface of the smartphone  1 , and performs imaging with the user of the smartphone  1  as a subject to acquire an image of the user. Note that although not illustrated, an imaging device is also arranged on the back surface of the smartphone  1 . 
     The display  13  displays an operation image generated by processing performed by an application program, an operation system, or the like, an image captured by the imaging device  12 , and the like. A touch sensor  13 T is superimposed on the upper surface of the display  13 , and the touch sensor  13 T detects a location on the display  13  touched by the user and outputs the location to the sensor hub  19 . 
     The communication module  14  performs communication via a predetermined network such as communication (call) through a mobile phone network or a public wireless communication network, or short-range wireless communication such as wireless LAN or Bluetooth (registered trademark). 
     The sensor unit  15  includes, for example, one or more predetermined sensors such as an acceleration sensor, a gyro sensor, an atmospheric pressure sensor, or a geomagnetic sensor, and outputs a detection result of each sensor to the sensor hub  19 . 
     The speaker  16  outputs voice of the other party, for example, when a call is made by using the smartphone  1 . The microphone  17  collects the voice of the user, for example, when a call is made by using the smartphone  1 . 
     The operating button  18  includes one or more buttons such as a power button or a volume button, detects a pressing operation by the user, and outputs the pressing operation to the sensor hub  19 . 
     The sensor hub  19  constantly monitors sensor devices such as the touch sensor  13 T, each sensor of the sensor unit  15 , and the operating button  18 , and detects an operation on the smartphone  1  and a predetermined state of the smartphone  1 . The sensor hub  19  is an arithmetic device (CPU) provided separately from the AP  20  so as to require less power even if operating in the always-on state in order to realize constant monitoring of the sensor device. 
     The AP  20  is an arithmetic device that executes an application program and the operation system stored in a storage unit, not illustrated, and includes a microprocessor, a graphics processing unit (GPU), and the like. 
     The power supply unit  21  includes, for example, a battery and a power supply control circuit or the like, and supplies power to each unit (circuit) of the smartphone  1 , detects a remaining voltage, and accumulates (charges) necessary power. 
     In some of the smartphones  1  configured as described above, a face authentication process of authenticating the face of the user can be executed. The face authentication process is used, for example, for user authentication when screen lock is unlocked. In a case where the face authentication process is executed, first, a detection process of detecting the user, such as whether the user is at an appropriate distance in front of the smartphone  1 , is performed. The detection process may be executed by the AP  20  that executes the face authentication process; however, the distance measuring module  11  of the smartphone  1  is also designed so as to be able to execute the detection process. 
     Hereinafter, the detection function of the distance measuring module  11  mounted on the smartphone  1  will be described in detail. 
     &lt;2. Schematic Configuration Example of Distance Measuring Module&gt; 
       FIG. 2  is a block diagram illustrating a detailed configuration example of the distance measuring module  11 . Note that  FIG. 2  also illustrates other blocks of the smartphone  1  related to the detection process of the distance measuring module  11 . 
     The distance measuring module  11  is a distance measuring module that performs distance measurement by the Indirect ToF method, and includes a light emitting unit  41 , a light emission controlling unit  42 , and a distance measuring sensor  43 . 
     The distance measuring module  11  irradiates an object with light, receives light (reflected light) obtained by reflection of the light (irradiation light) by the object, and thus generates and outputs a depth map (distance image) as distance information to the object and a reliability map (reliability image) as luminance information. 
     The distance measuring sensor  43  includes a light receiving unit  51  and a signal processing unit  52 . The distance measuring sensor  43  can be manufactured as one-chip semiconductor package (CSP) including a laminated substrate in which a first semiconductor substrate and a second semiconductor substrate are laminated, a pixel array unit is arranged on the first semiconductor substrate having an incident surface to which reflected light is input, and a logic circuit, a memory circuit, and the like to be the signal processing unit  52  are arranged on the second semiconductor substrate. Note that, as a matter of course, the distance measuring sensor  43  may include two or more divided chips, or may include a one-chip semiconductor package (CSP) including a laminated substrate of three or more semiconductor substrates. 
     The light emitting unit  41  includes, for example, an infrared laser diode or the like as a light source, emits light while performing modulation at a timing corresponding to a light emission control signal supplied from the light emission controlling unit  42  according to control performed by the light emission controlling unit  42 , and irradiates an object with irradiation light. 
     The light emission controlling unit  42  controls light emission from the light emitting unit  41  by supplying to the light emitting unit  41  a light emission control signal for controlling a frequency (for example, 20 MHz or the like) and a light emission amount when the light source is caused to emit light. Furthermore, the light emission controlling unit  42  supplies the light emission control signal also to the light receiving unit  51  in order to drive the light receiving unit  51  in accordance with the light emission timing of the light emitting unit  41 . 
     The light receiving unit  51  receives reflected light obtained by reflection of irradiation light by the object. Then, the light receiving unit  51  includes a pixel array unit in which pixels which each generate electric charge according to the amount of received light and output a signal according to the electric charge are two-dimensionally arranged in a matrix in the row direction and the column direction, and each pixel outputs a light reception signal A and a light reception signal B obtained by distributing the electric charge according to the amount of received light to a first tap and a second tap to the signal processing unit  52 . The light receiving operation of the light receiving unit  51  will be described later in detail with reference to  FIGS. 3 to 7 . 
     The signal processing unit  52  includes a control unit  61 , a depth calculation unit  62 , and a detection processing unit  63 . 
     If a predetermined operation serving as a trigger for starting a detection process is detected in the sensor unit  15 , the operating button  18 , the touch sensor  13 T, or the like, the sensor hub  19  supplies a start command for starting distance measurement to the control unit  61  of the distance measuring sensor  43 . Examples of the operation that is a trigger for starting a detection process include an operation of moving the smartphone  1  supplied from an inertial sensor (gyro sensor, acceleration sensor) that is one of the sensor units  15 , an operation of pressing the power button that is one of the operating buttons  18 , and an operation of starting a predetermined application program detected by the touch sensor  13 T. 
     If a distance measurement start command is supplied from the sensor hub  19 , the control unit  61  instructs the light emission controlling unit  42  to start light emission. The control unit  61  can specify a predetermined frequency and a light emission amount so that the exposure amount is appropriately adjusted (exposure is controlled) on the basis of the light reception signal supplied from the light receiving unit  51 . Note that in an initial state in which no light reception signal is supplied from the light receiving unit  51 , a frequency and a light emission amount determined in advance as initial values are set. 
     Moreover, the control unit  61  selects a predetermined operation mode from among a plurality of operation modes registered in advance, and causes the detection processing unit  63  to execute a predetermined detection process corresponding to the operation mode that is selected. For example, the operation mode is specified by a command or the like from the sensor hub  19 , or specified by a high or low voltage signal of an input/output terminal connected to the sensor hub  19 . Therefore, the control unit  61  detects the operation mode specified by the sensor hub  19  and selects the operation mode that is detected. 
     The depth calculation unit  62  generates a depth map and a reliability map from two light reception signals A and B of each pixel supplied from the light receiving unit  51 . More specifically, the depth calculation unit  62  calculates a depth value, which is a distance from the distance measuring module  11  to the object, for each pixel of the light receiving unit  51 . Then, the depth calculation unit  62  generates a depth map in which a depth value is stored as a pixel value of each pixel. Furthermore, the depth calculation unit  62  also calculates the reliability of the calculated depth value for each pixel of the light receiving unit  51 , and generates a reliability map in which the reliability is stored as the pixel value of each pixel. 
     The detection processing unit  63  executes a predetermined detection process by using at least one of the depth map as the distance information and the reliability map as the luminance information, in accordance with the operation mode specified by the control unit  61 . Then, the detection processing unit  63  outputs the result of the detection process to the sensor hub  19  together with the depth map and the reliability map. 
     Under the control of the control unit  61 , the detection processing unit  63  changes the type (processing content), the order (sequence), the number, and the like of the detection processes according to the operation mode. In other words, the control unit  61  causes the detection processing unit  63  to execute predetermined detection processes different in type (processing content), order (sequence), number, and the like according to the operation mode. Details of the detection process will be described later. 
     The result of the detection process, the depth map, and the reliability map output to the sensor hub  19  are supplied to the AP  20 . The AP  20  executes the face authentication process on the basis of the depth map and the reliability map. 
     &lt;3. Distance Measurement Operation of Distance Measuring Sensor by Indirect ToF Method&gt; 
     Before explaining the detection function of the distance measuring sensor  43 , distance measuring operation of the distance measuring sensor  43  as a premise thereof will be described with reference to  FIGS. 3 to 7 . 
       FIG. 3  illustrates a detailed configuration example of the light receiving unit  51 . 
     The light receiving unit  51  includes a pixel array unit  72  in which pixels  71  which each generate electric charge according to the amount of received light and output a signal according to the electric charge are two-dimensionally arranged in a matrix in the row direction and the column direction, and a drive control circuit  73  arranged in a peripheral region of the pixel array unit  72 . 
     The drive control circuit  73  outputs a control signal (for example, a distribution signal DIMIX, a selection signal ADDRESS DECODE, a reset signal RST, and the like to be described later) for controlling driving of the pixel  71  on the basis of, for example, a light emission control signal supplied from the light emission controlling unit  42 . 
     The pixel  71  includes a photodiode  81 , and a first tap  82 A and a second tap  82 B that detect electric charge photoelectrically converted by the photodiode  81 . In the pixel  71 , electric charge generated in the one photodiode  81  is distributed to the first tap  82 A or the second tap  82 B. Then, the electric charge generated in the photodiode  81  and distributed to the first tap  82 A is output as a light reception signal A from a signal line  83 A, and the electric charge generated in the photodiode  81  and distributed to the second tap  82 B is output as a light reception signal B from a signal line  83 B. 
     The first tap  82 A includes a transfer transistor  91 A, a floating diffusion (FD) unit  92 A, a selection transistor  93 A, and a reset transistor  94 A. Similarly, the second tap  82 B includes a transfer transistor  91 B, an FD unit  92 B, a selection transistor  93 B, and a reset transistor  94 B. 
     Operation of the pixel  71  will be described. 
     As illustrated in  FIG. 4 , the light emitting unit  41  outputs irradiation light modulated (one cycle=2T) so as to repeat on/off of irradiation at an irradiation time T, and the photodiode  81  receives the reflected light with a delay of a delay time ΔT corresponding to the distance to the object. Furthermore, a distribution signal DIMIX_A controls on/off of the transfer transistor  91 A, and a distribution signal DIMIX_B controls on/off of the transfer transistor  91 B. The distribution signal DIMIX_A is a signal having the same phase as that of the irradiation light, and the distribution signal DIMIX_B has a phase obtained by inverting the phase of the distribution signal DIMIX_A. 
     Therefore, in  FIG. 3 , electric charge generated by reception of the reflected light by the photodiode  81  is transferred to the FD unit  92 A while the transfer transistor  91 A is turned on according to the distribution signal DIMIX_A, and is transferred to the FD unit  92 B while the transfer transistor  91 B is turned on according to the distribution signal DIMIX_B. Therefore, in a predetermined period during which irradiation with the irradiation light for the irradiation time T is periodically performed, the electric charge transferred via the transfer transistor  91 A is sequentially accumulated in the FD unit  92 A, and the electric charge transferred via the transfer transistor  91 B is sequentially accumulated in the FD unit  92 B. 
     Then, if the selection transistor  93 A is turned on according to a selection signal ADDRESS DECODE_A after the end of the period for accumulating electric charge, the electric charge accumulated in the FD unit  92 A is read via the signal line  83 A, and the light reception signal A corresponding to the amount of the electric charge is output from the light receiving unit  51 . Similarly, if the selection transistor  93 B is turned on according to a selection signal ADDRESS DECODE_B, the electric charge accumulated in the FD unit  92 B is read via the signal line  83 B, and the light reception signal B corresponding to the amount of the electric charge is output from the light receiving unit  51 . Furthermore, the electric charge accumulated in the FD unit  92 A is discharged if the reset transistor  94 A is turned on according to a reset signal RST_A, and the electric charge accumulated in the FD unit  92 B is discharged if the reset transistor  94 B is turned on according to a reset signal RST_B. 
     As described above, the pixel  71  distributes the electric charge generated by the reflected light received by the photodiode  81  to the first tap  82 A or the second tap  82 B according to the delay time ΔT, and outputs the light reception signal A and the light reception signal B. Then, the delay time ΔT corresponds to the time taken for the light emitted from the light emitting unit  41  to fly to the object, be reflected by the object, and then fly to the light receiving unit  51 , that is, corresponds to the distance to the object. Therefore, the distance measuring module  11  can obtain the distance (depth value) to the object according to the delay time ΔT on the basis of the light reception signal A and the light reception signal B. 
     However, in the pixel array unit  72 , there is a case where the light reception signal A and the light reception signal B are affected differently for each pixel  71  due to a deviation (sensitivity difference) in characteristics of each element such as the photodiode  81  and the pixel transistor such as the transfer transistor  91  included in each pixel  71 . Therefore, in the distance measuring module  11  of the Indirect ToF method, a technique of removing the sensitivity difference between the taps of each pixel and improving the SN ratio by acquiring the light reception signal A and the light reception signal B obtained by receiving reflected light by changing the phase in the same pixel  71  is adopted. 
     As a method of receiving reflected light by changing the phase and calculating the depth value, for example, a detection method by using two phases (2-phase method) and a detection method by using four phases (4-phase method) will be described. 
     As illustrated in  FIG. 5 , the light receiving unit  51  receives reflected light at light receiving timings with phases shifted by 0°, 90°, 180°, and 270° with respect to the irradiation timing of irradiation light. More specifically, the light receiving unit  51  receives reflected light by changing the phase in a time division manner such that in a certain frame period, light is received with the phase set to 0° with respect to the irradiation timing of the irradiation light, in the next frame period, light is received with the phase set to 90°, in the next frame period, light is received with the phase set to 180°, and in the next frame period, light is received with the phase set to 270°. 
       FIG. 6  is a diagram in which the exposure periods of the first tap  82 A of the pixel  71  in the respective phases of 0°, 90°, 180°, and 270° are arranged so that the phase difference can be easily understood. 
     As illustrated in  FIG. 6 , in the first tap  82 A, a light reception signal A obtained by receiving light in the same phase (phase 0°) as the irradiation light is referred to as a light reception signal A 0 , a light reception signal A obtained by receiving light in the phase (phase 90°) shifted by 90° from the irradiation light is referred to as a light reception signal A 90 , a light reception signal A obtained by receiving light in a phase (phase 180°) shifted by 180° from the irradiation light is referred to as a light reception signal A 180 , and a light reception signal A obtained by receiving light in a phase (phase 270°) shifted by 270° from the irradiation light is referred to as a light reception signal A 270 . 
     Furthermore, even though illustration is omitted, in the second tap  82 B, a light reception signal B obtained by receiving light in the same phase (phase 0°) as the irradiation light is referred to as a light reception signal B 0 , a light reception signal B obtained by receiving light in the phase (phase 90°) shifted by 90° from the irradiation light is referred to as a light reception signal B 90 , a light reception signal B obtained by receiving light in a phase (phase 180°) shifted by 180° from the irradiation light is referred to as a light reception signal B 180 , and a light reception signal B obtained by receiving light in a phase (phase 270°) shifted by 270° from the irradiation light is referred to as a light reception signal B 270 . 
       FIG. 7  is a diagram illustrating methods of calculating a depth value and a reliability by using the 2-phase method and the 4-phase method. 
     In the Indirect ToF method, the depth value d can be obtained by the following Formula (1). 
     
       
         
           
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     In Formula (1), c represents a speed of light, AT represents a delay time, and f represents a modulation frequency of light. Furthermore, φ in Formula (1) represents the phase shift amount [rad] of reflected light and is expressed by the following Formula (2). 
     
       
         
           
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     In the 4-phase method, I and Q in Formula (2) are calculated by the following Formulas (3) using the light reception signals A 0  to A 270  and the light reception signals B 0  to B 270  obtained by setting the phases to 0°, 90°, 180°, and 270°. I and Q are signals which each are obtained by assuming that the luminance change of irradiation light is a cos wave and converting the phase of the cos wave from the polar coordinate to the orthogonal coordinate system (IQ plane). 
         I=c   0   −c   180 =( A   0   −B   0 )−( A   180   −B   180 )
 
         Q=c   90   −c   270 =( A   90   −B   90 )−( A   270   −B   270 )   (3)
 
     In the 4-phase method, for example, by taking a difference between light reception signals in opposite phases in the same pixel, such as “A 0 -A 180 ” and “A 90 -A 270 ” in Formula (3), it is possible to remove characteristic variation between taps existing in each pixel, that is, fixed pattern noise. 
     In contrast, in the 2-phase method, the depth value d to the object can be obtained by using only two phases in an orthogonal relationship among the light reception signals A 0  to A 270  and the light reception signals B 0  to B 270  obtained by setting the phases to 0°, 90°, 180°, and 270°. For example, in a case where the light reception signals A 0  and B 0  in the phase of 0° and the light reception signals A 90  and B 90  in the phase of 90° are used, I and Q in Formula (2) are expressed by the following Formulas (4). 
         I=c   0   −c   180 =( A   0   −B   0 ) 
         Q=c   90   −c   270 =( A   90   −B   90 )  (4)
 
     For example, in a case where the light reception signals A 180  and B 180  in the phase of 180° and the light reception signals A 270  and B 270  in the phase of 270° are used, I and Q in Formula (2) are expressed by the following Formulas (5). 
         I=c   0   −c   180 =−( A   180   −B   180 )
 
         Q=c   90   −c   270 =−( A   270   −B   270 )  (5)
 
     In the 2-phase method, the characteristic variation between the taps existing in each pixel cannot be removed; however, the depth value d to the object can be obtained only by the light reception signals in the two phases. Therefore, distance measurement can be performed at a frame rate twice of that of the 4-phase method. The characteristic variation between the taps can be adjusted by a correction parameter such as a gain or an offset. 
     In the 2-phase method and the 4-phase method, the reliability cnf can be obtained by the following Formula (6). 
       [Mathematical Expression 3] 
         cnf =√{square root over ( I   2   +Q   2 )}  (6)
 
     In the present embodiment, it does not matter whether the distance measuring module  11  uses the I signal and the Q signal corresponding to the delay time ΔT calculated by the 4-phase method or the I signal and the Q signal corresponding to the delay time ΔT calculated by the 2-phase method to use the depth value d and the reliability cnf. Either the 4-phase method or the 2-phase method may be fixedly used, or for example, a method of appropriately selecting the 4-phase method or the 2-phase or blending the 4-phase method and the 2-phase according to the motion of the object or the like may be used. Hereinafter, for the sake of simplicity, it is assumed that the 4-phase method is employed. 
     &lt;4. Detection Process According to Operation Mode&gt; 
     The detection processing unit  63  executes a predetermined detection process by using at least one of the depth map or the reliability map supplied from the depth calculation unit  62  according to the current operation mode selected from among a plurality of operation modes, and outputs the result of the detection process to the sensor hub  19  together with the depth map and the reliability map. 
       FIG. 8  illustrates specific detection processes executed in predetermined operation modes among the plurality of operation modes. Note that the four operation modes, that is, the operation modes A to D illustrated in  FIG. 8  are examples of the operation modes of the signal processing unit  52 , and the signal processing unit  52  has another operation mode. 
     The detection processing unit  63  can execute, for example, each of a proximity detection process, a head portion detection process, a face detection process, and a pupil detection process as a detection process using at least one of the depth map or the reliability map. The proximity detection process is a process of detecting whether or not there is an object (nearby object) within a predetermined distance from the smartphone  1 . Note that, regarding preprocessing of the face authentication process, even though the original target of the proximity detection process is the face (head) of the user, in a proximity process, if there is a predetermined object (nearby object) at a nearby location from the smartphone  1 , including but not limited to a human face, it is determined that there is a nearby object. The head portion detection process is a process of detecting the head portion of the user (human). The face detection process is a process of detecting the face of the user. The pupil detection process is a process of detecting an eye and a line-of-sight of the user. 
     The detection process in the operation mode A is a process of sequentially executing the proximity detection process, the head portion detection process, the face detection process, and the pupil detection process in this order, and sequentially repeating the process of executing a next second detection process in a case where a detection target is detected in a first detection process executed earlier. Then, in a case where a pupil, which is a detection target, is detected in the pupil detection process, which is the last process, the detection result of the pupil is output to the sensor hub  19  together with the depth map and the reliability map. 
     Similarly to the operation mode A, the detection process in the operation mode B is a process of sequentially executing the proximity detection process, the head portion detection process, the face detection process, and the pupil detection process in this order, and sequentially repeating the process of executing a next second detection process in a case where a detection target is detected in a first detection process executed earlier. The detection process in the operation mode B is different from the detection process in the operation mode A in that in a case where a detection target is detected in each detection process, the detection result is output to the sensor hub  19 . Then, in a case where a pupil, which is a detection target, is detected in the pupil detection process, which is the last process, the detection result of the pupil is output to the sensor hub  19  together with the depth map and the reliability map. 
     The detection process in the operation mode C is a process of executing only the proximity detection process and the head portion detection process among the four detection processes executed in the operation mode B. In a case where the user is detected at a nearby location in the proximity process, the detection result is output to the sensor hub  19 , and in a case where the head portion is detected in the head portion detection process, which is the next process, the detection result, the depth map, and the reliability map are output to the sensor hub  19 . 
     Note that the detection process in the operation mode C is a process of executing two processes, that is, the proximity detection process and the head portion detection process among the four detection processes, that is, the proximity detection process, the head portion detection process, the face detection process, and the pupil detection process; however, the detection processing unit  63  also has another operation mode of executing a detection process in which one or more of the four detection processes are combined in any order. For example, the detection processing unit  63  also has an operation mode in which only the proximity process is executed and the detection result, the depth map, and the reliability map are output to the sensor hub  19 , an operation mode in which the proximity process and the face detection process are executed in this order, and in a case where the user is detected at a nearby location, the detection result is output to the sensor hub  19  and then the face detection process is executed, and in a case where a face is detected, the detection result, the depth map, and the reliability map are output to the sensor hub  19 , and the like. 
     Similarly to the operation mode A, the detection process of the operation mode D is a process of executing the proximity detection process, the head portion detection process, the face detection process, and the pupil detection process in this order. The detection process of the operation mode D is different from the detection process of the operation mode A in that the detection result of a first detection process executed earlier is output to the sensor hub  19 , and a second detection process, which is the next process, is executed when the second detection process is instructed from the sensor hub  19  on the basis of the detection result of the first detection process. Then, in a case where a pupil is detected in the pupil detection process, which is the last process, the pupil detection result, the depth map, and the reliability map are output to the sensor hub  19 . 
     The detection process of an operation mode includes at least one of the proximity detection process, the head portion detection process, the face detection process, or the pupil detection process. In the detection process of any operation mode, in a case where the last detection process of the series of detection processes according to the operation mode is successful (a detection target is detected), the detection result, the depth map, and the reliability map are output to the sensor hub  19 . 
       FIG. 9  is a diagram explaining a specific processing example of the proximity detection process. 
     Note that, in the present embodiment, it is assumed that the pixel array unit  72  of the light receiving unit  51  has a pixel array of 640 pixels in the horizontal direction and 480 pixels in the vertical direction. Furthermore, it is assumed that the depth map and the reliability map used when the detection process is executed are generated on the basis of a light reception signal in which an exposure amount is appropriately adjusted (exposure is controlled) in the light receiving unit  51  on the basis of a light emission control signal for controlling the frequency and the light emission amount. 
     In the proximity detection process, the detection processing unit  63  groups all the 640×480 pixels into 32×24 blocks each including 20 pixels in each of the horizontal direction and the vertical direction. Then, the detection processing unit  63  determines one predetermined block among all the 32×24 blocks as a detection target block. The detection target block is, for example, a block located at the center of the pixel array unit  72 . 
     Next, the detection processing unit  63  calculates an average value d_ave of the depth values d of the 20×20 pixels constituting the detection target block and an average value cnf_ave of the reliabilities cnf. Then, in a case where the average value d_ave of the depth values is in a predetermined range determined to be a proximity distance and the average value cnf_ave of the reliabilities cnf is in a predetermined range determined to be normal detection, the detection processing unit  63  detects that the user is at a nearby location from the smartphone  1 . For example, assuming that a distance in a case where a person holds the smartphone  1  by hand and images himself/herself is about 70 cm at the maximum, it can be determined that a distance is a proximity distance in a case where the average value d_ave of the depth values is within 70 cm. 
       FIG. 10  is a diagram explaining a specific processing example of the head portion detection process. 
     In the head portion detection process, the detection processing unit  63  calculates the average value cnf_ave of the reliabilities cnf of all the 32×24 blocks, and detects the head portion of the user on the basis of the average value cnf_ave of the reliabilities cnf of all the blocks that is calculated. Since the reliability cnf corresponds to the luminance information (luminance value), for example, the average value cnf_ave of the reliabilities cnf of the 32×24 blocks can be regarded as a low-resolution two-dimensional image, and the head portion of the user can be detected in the manner of pattern matching. 
       FIG. 11  is a diagram explaining a specific processing example of the face detection process. 
     In the face detection process, the detection processing unit  63  groups all the 640×480 pixels into 320×240 blocks each including two pixels in each of the horizontal direction and the vertical direction. Then, the detection processing unit  63  calculates the average value cnf_ave of the reliabilities cnf of all the 320×240 blocks, and detects the face of the user on the basis of the average value enf_ave of the reliabilities cnf of all the blocks that is calculated. For example, similarly to the head portion detection process, regarding the face of the user, the average value cnf_ave of the reliabilities cnf of all the 320×240 blocks is regarded as a low-resolution two-dimensional image, and it can be determined that the face of the user is detected in a case where the face, the eyes, and the mouth of the user are detected in the manner of pattern matching. 
       FIG. 12  is a diagram illustrating a specific processing example of the pupil detection process. 
     In the pupil detection process, the detection processing unit  63  detects a pupil of the user by using the average value cnf_ave of the reliabilities cnf of all the 640×480 pixels as it is. Regarding a pupil of the user, for example, similarly to the face detection process, in a case where the vicinity of the position of an eye of the face is detected in the manner of pattern matching and a state in which an eye of the user is opened and is directed in a predetermined direction is detected, it can be determined that a pupil of the user is detected. 
     As described above, for example, in a case where the four detection processes, that is, the proximity detection process, the head portion detection process, the face detection process, and the pupil detection process are sequentially executed as a series of detection processes, the detection processing unit  63  can execute the detection processes by setting the resolution of the depth map or the reliability map regarded as a two-dimensional image such that the resolution becomes higher as the processing proceeds to a later detection process. Therefore, it is possible to balance the accuracy (high accuracy) of the detection process and the processing time (high-speed processing time). 
     Note that, although illustration is omitted, as in a general distance measuring sensor, an operation mode for generating and outputting only a depth map and a reliability map on the basis of the light reception signal of each pixel without executing the detection process is naturally prepared for the distance measuring sensor  43 . 
     &lt;Depth Measurement Process in Operation Mode B&gt; 
     Next, a depth measurement process executed by the distance measuring module  11  in a case where the operation mode B of  FIG. 8  is set as the operation mode will be described with reference to the flowchart of  FIG. 13 . This process is started, for example, when a distance measurement start command is supplied from the sensor hub  19 . 
     First, in step S 11 , the control unit  61  of the signal processing unit  52  instructs the light emission controlling unit  42  to start light emission, and sets the operation mode specified by the sensor hub  19 . If the light emission controlling unit  42  is instructed to start light emission, the light emission controlling unit  42  supplies to the light emitting unit  41  a light emission control signal for controlling the frequency and the light emission amount at the time of causing the light source to emit light. The light emitting unit  41  emits light while performing modulation at a timing corresponding to the light emission control signal supplied from the light emission controlling unit  42 , and irradiates an object with irradiation light. 
     In step S 12 , the light receiving unit  51  executes a photoelectric conversion process of receiving and photoelectrically converting light (reflected light) reflected by the object, and outputs the light reception signal A and the light reception signal B obtained by distributing electric charge to the first tap  82 A and the second tap  82 B in each pixel  71  of the pixel array unit  72  to the depth calculation unit  62  of the signal processing unit  52 . 
     In step S 13 , the depth calculation unit  62  generates a depth map and a reliability map from the two light reception signals A and B of each pixel  71  supplied from the pixel array unit  72  of the light receiving unit  51 . The depth map and the reliability map that are generated are supplied to the detection processing unit  63 . 
     In step S 14 , the detection processing unit  63  executes the proximity detection process of detecting whether or not the user is at a nearby location from the smartphone  1 . 
     Then, in step S 15 , the detection processing unit  63  determines whether a nearby object is detected on the basis of the execution result of the proximity detection process. In a case where it is determined in step S 15  that a nearby object is not detected, the processing returns to step S 12 . 
     In contrast, in a case where it is determined in step S 15  that a nearby object is detected, the processing proceeds to step S 16 , and the detection processing unit  63  outputs the proximity detection result to the sensor hub  19 , and the processing proceeds to step S 17 . 
     In step S 17 , the detection processing unit  63  executes the head portion detection process of detecting the head portion of the user. 
     Then, in step S 18 , the detection processing unit  63  determines whether the head portion is detected on the basis of the execution result of the head portion detection process. In a case where it is determined in step S 18  that the head portion is not detected, the processing returns to step S 12 . 
     In contrast, in a case where it is determined in step S 18  that the head portion is detected, the processing proceeds to step S 19 , and the detection processing unit  63  outputs the head portion detection result to the sensor hub  19 , and the processing proceeds to step S 20 . 
     In step S 20 , the detection processing unit  63  executes the face detection process of detecting the face of the user. 
     Then, in step S 21 , the detection processing unit  63  determines whether the face is detected on the basis of the execution result of the face detection process. In a case where it is determined in step S 21  that the face is not detected, the processing returns to step  312 . 
     In contrast, in a case where it is determined in step S 21  that the face is detected, the processing proceeds to step S 22 , and the detection processing unit  63  outputs the face detection result to the sensor hub  19  and the processing proceeds to step S 23 . 
     In step S 23 , the detection processing unit  63  executes the pupil detection process of detecting an eye and line-of-sight of the user. 
     Then, in step S 24 , the detection processing unit  63  determines whether a pupil is detected on the basis of the execution result of the pupil detection process. In a case where it is determined in step S 24  that a pupil is not detected, the processing returns to step S 12 . 
     In contrast, in a case where it is determined in step S 24  that a pupil is detected, the processing proceeds to step S 25 , and the detection processing unit  63  outputs the pupil detection result to the sensor hub  19  together with the depth map and the reliability map, and the processing is terminated. 
     The depth measurement process in a case where the operation mode B is set as the operation mode is executed as described above. 
     Note that the depth measurement process in a case where the operation mode A is set as the operation mode corresponds to the process in which the processes of outputting the detection results in the respective detection processes other than the pupil detection process, which is the last process, specifically, steps S 16 , S 19 , and S 22  are omitted in the depth measurement process of  FIG. 13 . 
     &lt;Depth Measurement Process in Operation Mode D&gt; 
     Next, a depth measurement process executed by the distance measuring module  11  in a case where the operation mode D of  FIG. 8  is set as the operation mode will be described with reference to the flowchart of  FIG. 14 . This process is started, for example, when a distance measurement start command is supplied from the sensor hub  19 . 
     The depth measurement process in the operation mode D is equal to the process in which the processes in steps S 47 , S 51 , and S 55  are added to the depth measurement process in the operation mode B illustrated in  FIG. 13 . 
     More specifically, step S 47  is added between step S 46  in  FIG. 14  corresponding to step S 16  in  FIG. 13  and step S 48  in  FIG. 14  corresponding to step S 17  in  FIG. 13 , step  351  is added between step S 50  in  FIG. 14  corresponding to step S 19  in  FIG. 13  and step S 52  in FIG.  14  corresponding to step S 20  in  FIG. 13 , and step S 55  is added between step S 54  in  FIG. 14  corresponding to step S 22  in  FIG. 13  and step S 56  in  FIG. 14  corresponding to step S 23  in  FIG. 13 . 
     In step  347 , after the proximity detection result is output to the sensor hub  19  in step S 46 , the detection processing unit  63  determines whether head portion detection is instructed from the sensor hub  19 . In a case where it is determined in step S 47  that head portion detection is not instructed, the processing returns to step S 42 . In contrast, in a case where it is determined in step S 47  that head portion detection is instructed, the processing proceeds to step S 48 , and the head portion detection process is executed. 
     In step S 51 , after the head portion detection result is output to the sensor hub  19  in step S 50 , the detection processing unit  63  determines whether face detection is instructed from the sensor hub  19 . In a case where it is determined in step S 51  that face detection is not instructed, the processing returns to step S 42 . In contrast, in a case where it is determined in step  351  that the face detection is instructed, the processing proceeds to step  352 , and the face detection process is executed. 
     In step S 55 , after the proximity detection result is output to the sensor hub  19  in step  354 , the detection processing unit  63  determines whether pupil detection is instructed from the sensor hub  19 . In a case where it is determined in step S 55  that pupil detection is not instructed, the processing returns to step S 42 . In contrast, in a case where it is determined in step S 55  that pupil detection is instructed, the processing proceeds to step S 56 , and the pupil detection process is executed. 
     As described above, the depth measurement process in a case where the operation mode D is set is different from the depth measurement process in a case where the operation mode B is set in that a next detection process is executed on the basis of an instruction to execute the next detection process from the sensor hub  19 . 
     Note that, in the depth measurement processes in  FIGS. 13 and 14 , in a case where the processing up to pupil detection is not finally successful, the procedure of infinitely continuing the depth measurement process is adopted. However, actually, for example, an error process of terminating the depth measurement process in a case where the individual detection process has not been successful for a certain period of time is incorporated. 
     &lt;5. Effect of Distance Measuring Sensor&gt; 
     An effect of the distance measuring sensor  43  having a detection function will be described with reference to  FIG. 15 . 
     As illustrated in A of  FIG. 15 , a general distance measuring sensor generates only a depth map and a reliability map and outputs the depth map and the reliability map as distance measurement data. In this case, the AP  20  executes the proximity detection process, the head portion detection process, the face detection process, and the pupil detection process on the basis of the depth map and the reliability map, and executes the face authentication process on condition that the pupil detection process is successful. Until the pupil detection process is successful, it is necessary to repeatedly execute the pupil detection process while acquiring a large number of depth maps and reliability maps, and the AP  20  is a device that requires a large amount of power. Therefore, the amount of power required by the smartphone  1  also increases. 
     In contrast, according to the distance measuring sensor  43  to which the present technology is applied, as illustrated in B of  FIG. 15 , not only the depth map and the reliability map can be generated but also the proximity detection process, the head portion detection process, the face detection process, and the pupil detection process can be executed, and only in a case where the pupil detection process is successful and the face can be accurately distinguished, the pupil detection result, the depth map, and the reliability map are output to the AP  20 . Therefore, the AP  20  is activated and the face authentication process is executed. 
     As a result, unnecessary activation of the AP can be suppressed and the amount of power required by the smartphone  1  can be reduced as compared with a case where the detection process as the preprocessing necessary for the face authentication process is executed by the AP  20 . 
     The distance measuring module  11  described above can be mounted on, in addition to the smartphone as described above, for example, an electronic apparatus such as a tablet terminal, a mobile phone, a personal computer, a game console, a television receiver, a wearable terminal, a digital still camera, or a digital video camera. 
     &lt;6. Example of Application to Moving Object&gt; 
     The technology according to the present disclosure (present technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of a moving object such as an automobile, an electric car, a hybrid electric car, a motorcycle, a bicycle, a personal mobility vehicle, an airplane, a drone, a ship, or a robot. 
       FIG. 16  is a block diagram illustrating a schematic configuration example of a vehicle control system which is an example of a moving object control system to which the technology according to the present disclosure can be applied. 
     A vehicle control system  12000  includes a plurality of electronic control units connected via a communication network  12001 . In the example illustrated in  FIG. 16 , the vehicle control system  12000  includes a drive-system control unit  12010 , a body-system control unit  12020 , an outside-vehicle information detection unit  12030 , an inside-vehicle information detection unit  12040 , and an integrated control unit  12050 . Furthermore, as a functional configuration of the integrated control unit  12050 , a microcomputer  12051 , an audio image output unit  12052 , and an in-vehicle network interface (I/F)  12053  are illustrated. 
     The drive-system control unit  12010  controls the operation of devices related to the drive system of a vehicle according to various programs. For example, the drive-system control unit  12010  functions as a control device for a drive force generation device for generating drive force of the vehicle such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting drive force to wheels, a steering mechanism that adjusts the steering angle of the vehicle, and a braking device that generates braking force of the vehicle. 
     The body-system control unit  12020  controls the operation of various devices provided on a vehicle body according to the various programs. For example, the body-system control unit  12020  functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as a headlamp, a back lamp, a brake lamp, a blinker, or a fog lamp. In this case, to the body-system control unit  12020 , radio waves or signals of various switches transmitted from a portable machine substituting for a key can be input. The body-system control unit  12020  receives input of these radio waves or signals, and controls a door lock device, a power window device, a lamp, and the like of the vehicle. 
     The outside-vehicle information detection unit  12030  detects information of the outside of the vehicle on which the vehicle control system  12000  is mounted. 
     For example, an imaging unit  12031  is connected to the outside-vehicle information detection unit  12030 . The outside-vehicle information detection unit  12030  causes the imaging unit  12031  to capture an image outside the vehicle, and receives the captured image. The outside-vehicle information detection unit  12030  may perform a process of detecting an object such as a person, a car, an obstacle, a sign, a character on a road surface, or the like or a distance detection process on the basis of the received image. 
     The imaging unit  12031  is an optical sensor that receives light and outputs an electric signal according to the light reception amount of the light. The imaging unit  12031  can output an electric signal as an image or can output the electric signal as information of distance measurement. Furthermore, light received by the imaging unit  12031  may be visible light or invisible light such as infrared light. 
     The inside-vehicle information detection unit  12040  detects information of vehicle inside. For example, a driver condition detector  12041  that detects the condition of a driver is connected to the inside-vehicle information detection unit  12040 . The driver condition detector  12041  includes, for example, a camera that captures an image of the driver, and the inside-vehicle information detection unit  12040  may calculate the degree of fatigue or the degree of concentration of the driver or may make a judgment as to whether or not the driver does not doze off, on the basis of detection information input from the driver condition detector  12041 . 
     The microcomputer  12051  can arithmetically operate a control target value of the drive force generation device, the steering mechanism, or the braking device, on the basis of information of the inside and outside of the vehicle acquired by the outside-vehicle information detection unit  12030  or the inside-vehicle information detection unit  12040 , and can output a control command to the drive-system control unit  12010 . For example, the microcomputer  12051  can perform coordinated control aiming at realizing functions of an advanced driver assistance system (ADAS) including collision avoidance or shock mitigation of a vehicle, follow-up traveling based on inter-vehicle distance, traveling while maintaining vehicle speed, vehicle collision warning, vehicle lane deviation warning, or the like. 
     Furthermore, the microcomputer  12051  can perform coordinated control aiming at automatic driving or the like of autonomously traveling without depending on an operation of the driver, by controlling the drive force generation device, the steering mechanism, the braking device, or the like on the basis of vehicle periphery information acquired by the outside-vehicle information detection unit  12030  or the inside-vehicle information detection unit  12040 . 
     Furthermore, the microcomputer  12051  can output a control command to the body-system control unit  12020  on the basis of the outside-vehicle information acquired by the outside-vehicle information detection unit  12030 . For example, the microcomputer  12051  can perform coordinated control aiming at antiglare such as switching from a high beam to a low beam by controlling the headlamp according to the position of the preceding car or the oncoming car detected by the outside-vehicle information detection unit  12030 . 
     The audio image output unit  12052  transmits an output signal of at least one of audio or an image to an output device capable of visually or aurally notifying a passenger or the outside of the vehicle of information. In the example of  FIG. 16 , an audio speaker  12061 , a display unit  12062 , and an instrument panel  12063  are illustrated as examples of the output device. For example, the display unit  12062  may include at least one of an on-board display or a head-up display. 
       FIG. 17  is a diagram illustrating examples of installation locations of the imaging unit  12031 . 
     In  FIG. 17 , a vehicle  12100  includes imaging units  12101 ,  12102 ,  12103 ,  12104 ,  12105  as the imaging unit  12031 . 
     For example, the imaging units  12101 ,  12102 ,  12103 ,  12104 ,  12105  are provided at locations such as a front nose, side mirrors, a rear bumper, a back door, and an upper portion of a windshield of a vehicle cabin of the vehicle  12100 . The imaging unit  12101  provided on the front nose and the imaging unit  12105  provided on the upper portion of the windshield inside the vehicle cabin mainly acquire images in front of the vehicle  12100 . The imaging units  12102 ,  12103  provided on the side mirrors mainly acquire images on lateral sides of the vehicle  12100 . The imaging unit  12104  provided on the rear bumper or the back door mainly acquires an image behind the vehicle  12100 . The front images acquired by the imaging units  12101 ,  12105  are mainly used to detect a preceding vehicle, a pedestrian, an obstacle, traffic lights, a traffic sign, a traffic lane, or the like. 
     Note that  FIG. 17  illustrates examples of the imaging ranges of the imaging units  12101  to  12104 . An imaging range  12111  indicates the imaging range of the imaging unit  12101  provided on the front nose, imaging ranges  12112 ,  12113  indicate the imaging ranges of the imaging units  12102 ,  12103  provided on the side mirrors, respectively, and an imaging range  12114  indicates the imaging range of the imaging unit  12104  provided on the rear bumper or the back door. For example, by overlapping pieces of image data captured by the imaging units  12101  to  12104 , a bird&#39;s eye view of the vehicle  12100  viewed from above can be obtained. 
     At least one of the imaging units  12101  to  12104  may have a function of acquiring distance information. For example, at least one of the imaging units  12101  to  12104  may be a stereo camera including a plurality of imaging elements, or an imaging element having pixels for phase difference detection. 
     For example, the microcomputer  12051  can extract, in particular, a closest stereoscopic object on a traveling road of the vehicle  12100 , the stereoscopic object traveling at predetermined speed (for example, 0 km/h or more) in substantially the same direction as in the vehicle  12100 , as a preceding car, by determining the distance to each stereoscopic object in the imaging ranges  12111  to  12114  and the temporal change of the distance (relative speed with respect to the vehicle  12100 ), on the basis of the distance information obtained from the imaging units  12101  to  12104 . Moreover, the microcomputer  12051  can set an inter-vehicle distance to be secured behind the preceding car, and can perform automatic brake control (including follow-up stop control), automatic acceleration control (including follow-up start control), or the like. As described above, it is possible to perform coordinated control aiming at automatic driving or the like of travelling autonomously without depending on the driver&#39;s operation. 
     For example, on the basis of the distance information obtained from the imaging units  12101  to  12104 , the microcomputer  12051  can classify stereoscopic object data relating to stereoscopic objects into two-wheeled vehicles, ordinary vehicles, large vehicles, pedestrians, utility poles, and other stereoscopic objects and extract them so as to be able to use them for automatic avoidance of obstacles. For example, the microcomputer  12051  identifies obstacles around the vehicle  12100  as obstacles visible to the driver of the vehicle  12100  and as obstacles hardly visible to the driver of the vehicle  12100 . Then, the microcomputer  12051  judges the collision risk indicating the degree of risk of collision with each obstacle, and in a situation where there is a possibility of collision with the collision risk equal to or more than a set value, the microcomputer  12051  can perform driving support for collision avoidance by outputting an alarm to the driver through the audio speaker  12061  or the display unit  12062  or performing forcible deceleration or avoidance steering through the drive-system control unit  12010 . 
     At least one of the imaging units  12101  to  12104  may be an infrared camera that detects infrared light. For example, the microcomputer  12051  can recognize a pedestrian by judging whether or not a pedestrian is present in the images captured by the imaging units  12101  to  12104 . Such pedestrian recognition is performed, for example, according to procedures for extracting characteristic points in images captured by the imaging units  12101  to  12104  as infrared cameras, and procedures for performing a pattern matching process on a series of characteristic points indicating the outline of an object to make a judgment as to whether or not the object is a pedestrian. If the microcomputer  12051  judges that a pedestrian is present in the captured images of the imaging units  12101  to  12104  and recognizes the pedestrian, the audio image output unit  12052  causes the display unit  12062  to display a square outline for emphasizing so as to be overlapped with the recognized pedestrian. Furthermore, the audio image output unit  12052  may cause the display unit  12062  to display an icon or the like indicating a pedestrian at a desired location. 
     An example of the vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to the inside-vehicle information detection unit  12040  or the driver condition detector  12041  in the above-described configuration. Specifically, by using the depth measurement process performed by the distance measuring module  11  as the inside-vehicle information detection unit  12040  or the driver condition detector  12041  to perform various types of detection processes before performing a driver&#39;s face recognition process, the face recognition process, which will be performed later, can be accurately performed, and the condition of the driver can be more accurately detected. 
     Note that the present technology can be applied to a method for amplitude modulating light projected onto an object, which is referred to as a Continuous-Wave method among Indirect ToF methods. Furthermore, the structure of the photodiode  81  of the light receiving unit  51  can also be applied to a distance measuring sensor having a current assisted photonic demodulator (CAPD) structure. 
     Moreover, the present technology may be applied to a distance measuring sensor of a structured light method. The embodiments of the present technology are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present technology. 
     Each of the plurality of the present technologies described in the present Description can be implemented independently as long as there is no contradiction. It is needless to say that a plurality of arbitrary present technologies can be implemented in combination. For example, part or entirety of the present technology described in any of the embodiments can be implemented in combination with part or entirety of the present technology described in another embodiment. Furthermore, part or entirety of an arbitrary present technology described above can be implemented in combination with another technology not described above. 
     Furthermore, for example, a configuration described as one device (or processing unit) may be divided and configured as a plurality of devices (or processing units). In contrast, the configurations described as a plurality of devices (or processing units) hereinbefore may be collectively configured as one device (or processing unit). Furthermore, it goes without saying that a configuration other than those described above may be added to the configuration of each device (or each processing unit). Moreover, if the configuration and operation of the system as a whole are substantially the same, part of the configuration of a certain device (or processing unit) may be included in the configuration of another device (or another processing unit). 
     Moreover, in the present Description, a system means a set of a plurality of constituents (devices, modules (components), or the like), and it does not matter whether or not all the constituents are in the same case. Therefore, each of a plurality of devices housed in separate cases and connected via a network, and one device in which a plurality of modules is housed in one case are a system. 
     Furthermore, for example, the program described above can be executed in an arbitrary device. In that case, it is sufficient that the device has a necessary function (functional block or the like) and can obtain necessary information. 
     Note that the effects described in the present Description are illustrations only and not limited, and may have effects other than the effects described in the present Description. 
     Note that the present technology can be configured as follows. 
     (1) 
     A distance measuring sensor including: 
     a light receiving unit that receives reflected light obtained by reflection of irradiation light emitted from a predetermined light emitting source by an object; 
     a depth calculation unit that calculates distance information to the object and luminance information from 
     a signal obtained by the light receiving unit; and a detection processing unit that executes a predetermined detection process by using at least one of the distance information or the luminance information in accordance with a current operation mode selected from among a plurality of operation modes, and outputs a result of a detection process to an outside together with the distance information and the luminance information. 
     (2) 
     The distance measuring sensor according to the (1), in which 
     one of the plurality of operation modes is a mode for executing a plurality of detection processes including a first detection process and a second detection process, and 
     the detection processing unit executes the second detection process in a case where a detection target is detected in the first detection process, and outputs a result of the second detection process to the outside together with the distance information and the luminance information in a case where a detection target is detected in the second detection process. 
     (3) 
     The distance measuring sensor according to the (2), in which 
     in a case where a detection target is detected in the first detection process, the detection processing unit outputs a result of the first detection process to the outside and executes the second detection process. 
     (4) 
     The distance measuring sensor according to any one of the (1) to (3), in which 
     one of the plurality of operation modes is a mode for executing a plurality of detection processes including a first detection process and a second detection process, and 
     the detection processing unit outputs a result of the first detection process to the outside in a case where a detection target is detected in the first detection process, executes the second detection process when an instruction to execute the second detection process is supplied from the outside, and outputs a result of the second detection process to the outside together with the distance information and the luminance information in a case where a detection target is detected in the second detection process. 
     (5) 
     The distance measuring sensor according to any one of the (1) to (4), in which 
     one of the plurality of operation modes is a mode for sequentially executing a plurality of detection processes, and 
     a resolution of the distance information or the luminance information in the plurality of detection processes becomes higher as processing proceeds to a later detection process. 
     (6) 
     The distance measuring sensor according to any one of the (1) to (5), in which 
     the detection process includes at least any one of a proximity detection process, a head portion detection process, a face detection process, or a pupil detection process. 
     (7) 
     The distance measuring sensor according to the (6), in which 
     one of the plurality of operation modes is a mode of the detection process for executing any one of the proximity detection process, the head portion detection process, the face detection process, or the pupil detection process. 
     (8) 
     The distance measuring sensor according to any one of the (1) to (7) further including 
     a control unit that selects a predetermined operation mode from among a plurality of operation modes and causes the detection processing unit to execute a predetermined detection process corresponding to a current operation mode. 
     (9) 
     A signal processing method including: 
     by using a distance measuring sensor, calculating distance information to an object and luminance information from a signal obtained by receiving reflected light obtained by reflection of irradiation light emitted from a predetermined light emitting source by the object; and 
     by using the distance measuring sensor, executing a predetermined detection process by using at least one of the distance information or the luminance information in accordance with a current operation mode selected from among a plurality of operation modes, and outputting a result of a detection process to an outside together with the distance information and the luminance information. 
     (10) 
     A distance measuring module including: 
     a light emitting unit that includes a predetermined light emitting source; and 
     a distance measuring sensor, the distance measuring sensor including: 
     a light receiving unit that receives reflected light obtained by reflection of irradiation light emitted from the predetermined light emitting source by an object; 
     a depth calculation unit that calculates distance information to the object and luminance information from a signal obtained by the light receiving unit; and 
     a detection processing unit that executes a predetermined detection process by using at least one of the distance information or the luminance information in accordance with a current operation mode selected from among a plurality of operation modes, and outputs a result of a detection process to an outside together with the distance information and the luminance information. 
     REFERENCE SIGNS LIST 
     
         
           1  Smartphone 
           11  Distance measuring module 
           15  Sensor unit 
           19  Sensor hub 
           20  AP (application processor) 
           11  Distance measuring module 
           41  Light emitting unit 
           42  Light emission controlling unit 
           43  Distance measuring sensor 
           51  Light receiving unit 
           52  Signal processing unit 
           61  Control unit 
           62  Depth calculation unit 
           63  Detection processing unit