Patent Publication Number: US-2022234592-A1

Title: Information processing device, vehicle, information processing method, and non-transitory storage medium

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2021-008756 filed on Jan. 22, 2021, incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to information processing devices, vehicles, information processing methods, and non-transitory storage media. 
     2. Description of Related Art 
     Many systems for preventing people and items from being left behind in a vehicle have been proposed in the art. For example, Japanese Unexamined Patent Application Publication No. 2012-123491 (JP 2012-123491 A) discloses a system that determines whether there is any item etc. left behind in a vehicle based on an image of the inside of the vehicle captured using a camera. 
     SUMMARY 
     The present disclosure provides an information processing device, a vehicle, an information processing method, and a non-transitory storage medium that accurately determine whether there is any person or item left behind in a vehicle. 
     A first aspect of the present disclosure is an information processing device associated with a vehicle. The information processing device includes a processor. The processor is configured to presume that a person or an item has been left behind in a rear seat of the vehicle, based on whether a rear door was opened and closed in a predetermined period before running of the vehicle and whether the rear door was opened and closed in a predetermined period after running of the vehicle. The processor is configured to perform sensing of the rear seat based on a presumption result. The processor is configured to notify a user based on a sensing result. 
     In the information processing device according to the first aspect of the present disclosure, the predetermined period before running of the vehicle may be a period from when the vehicle is unlocked until the vehicle starts to move. The predetermined period after running of the vehicle may be a period from when the vehicle is stopped until the vehicle is locked. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to presume that the person or the item has been left behind in the rear seat of the vehicle when the rear door was opened and closed in the predetermined period before running of the vehicle but the rear door was not opened and closed in the predetermined period after running of the vehicle. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to perform sensing of the rear seat using a seat sensor mounted in the vehicle. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to perform sensing of the rear seat using a camera that captures an image of inside of the vehicle. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to determine whether there is the person in the rear seat based on the sensing result. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to give a first notification using a terminal associated with the user. The processor may be configured to give a second notification using a device other than the terminal associated with the user when there is no response to the first notification from the user within a predetermined period. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to give the second notification when the processor determines that there is the person in the rear seat. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to further acquire information on a temperature inside a vehicle cabin of the vehicle. The processor may be configured to determine whether the temperature inside the vehicle cabin of the vehicle is higher than a predetermined value, based on the information on the temperature inside the vehicle cabin. The processor may be configured to give the second notification when the processor determines that there is the person in the rear seat and also determines that the temperature inside the vehicle cabin of the vehicle is higher than the predetermined value. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to give the second notification by operating an alarm of the vehicle. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to send data for giving the second notification to a center server that manages the vehicle. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to give a first notification when the processor determines that there is no person in the rear seat. The processor may be configured to give a second notification by a method different from the first notification when the processor determines that there is the person in the rear seat. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to acquire information on a temperature inside a vehicle cabin of the vehicle. The processor may be configured to give the second notification when the processor determines that there is the person in the rear seat and also determines that the temperature inside the vehicle cabin of the vehicle is higher than a predetermined value. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to give the second notification by operating an alarm of the vehicle. 
     In the information processing device according to the first aspect of the present disclosure, the processor may be configured to send data for giving the second notification to a center server that manages the vehicle. 
     A second aspect of the present disclosure is a vehicle including: a sensor that senses inside of a vehicle cabin of the vehicle; and a processor. The processor is configured to presume that a person or an item has been left behind in a rear seat of the vehicle, based on whether a rear door was opened and closed in a predetermined period before running of the vehicle and whether the rear door was opened and closed in a predetermined period after running of the vehicle. The processor is configured to perform sensing of the rear seat based on a presumption result. The processor is configured to notify a user based on a sensing result. 
     In the vehicle according to the second aspect of the present disclosure, the processor may be configured to presume that the person or the item has been left behind in the rear seat of the vehicle when the rear door was opened and closed in the predetermined period before running of the vehicle but the rear door was not opened and closed in the predetermined period after running of the vehicle. 
     In the vehicle according to the second aspect of the present disclosure, the processor may be configured to determine whether there is the person in the rear seat based on the sensing result. 
     A third aspect of the present disclosure is an information processing method including: presuming that a person or an item has been left behind in a rear seat of a vehicle, based on whether a rear door was opened and closed in a predetermined period before running of the vehicle and whether the rear door was opened and closed in a predetermined period after running of the vehicle; performing sensing of the rear seat based on a presumption result; and notifying a user based on a sensing result. 
     Instructions that cause a processor to perform the information processing method according to the third aspect of the present disclosure may be stored in a non-transitory storage medium. 
     The other aspect provides a program that causes a computer to perform the above information processing method or a computer-readable storage medium storing the program in a non-transitory manner. 
     According to the present disclosure, the presence of a person or an item left behind in the vehicle can be accurately determined. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein: 
         FIG. 1  is a system configuration diagram of a vehicle system according to an embodiment; 
         FIG. 2  is a block diagram showing components of an in-vehicle device and components of a vehicle platform; 
         FIG. 3  illustrates state transition of a vehicle; 
         FIG. 4  illustrates vehicle data stored in a storage unit; 
         FIG. 5  illustrates the positions of doors of the vehicle; 
         FIG. 6  is a block diagram showing components of a user terminal; 
         FIG. 7  is a flowchart of a process that is performed by an in-vehicle device; 
         FIG. 8  is a flowchart of a process of step S 19 ; 
         FIG. 9  is a flowchart of a process of step S 24  in a first embodiment; 
         FIG. 10  is a flowchart of the process of step S 24  in a second embodiment; 
         FIG. 11  is a flowchart of the process of step S 24  in a third embodiment; 
         FIG. 12  is a flowchart of the process of step S 24  in a fourth embodiment; 
         FIG. 13  is a flowchart of the process of step S 24  in a fifth embodiment; and 
         FIG. 14  is a flowchart of the process of step S 24  in a fifth embodiment (modification). 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     One aspect of the present disclosure is an information processing device that is mounted on a vehicle. Specifically, the information processing device includes a control unit configured to: presume that a person or an item has been left behind in a rear seat of the vehicle, based on whether a rear door was opened and closed in a predetermined period before running of the vehicle and whether the rear door was opened and closed in a predetermined period after running of the vehicle; perform sensing of the rear seat based on the presumption result; and notify a user based on the sensing result. 
     The rear door is a door to access the rear seat, that is, the seat located behind the driver&#39;s seat. For example, when the rear door was opened and closed before the vehicle started to move but the rear door was not opened after the vehicle finished moving, it can be determined that a person or an item may have been left behind in the rear seat. However, the determination result may be erroneous when such a determination is made based only on opening and closing of the rear door. For example, in a conventional system, it may be determined that a person or an item has been left behind and an alarm may be given when the rear seat was cleaned before running of the vehicle or when the item was unloaded before running of the vehicle. When trying to prevent a person or an item from being left behind in the vehicle by sensing the inside of the vehicle, it is difficult to distinguish whether a person or an item has been left behind in the vehicle or an item has just been left in the vehicle. 
     In order to deal with this problem, the information processing device according to the present disclosure presumes that a person or an item has been left behind in the rear seat of the vehicle based on opening and closing of the rear door, and determines whether sensing of the rear seat should be performed based on the presumption result. That is, when it is suspected that a person or an item has been left behind in the rear seat, sensing of the inside of the vehicle is performed. According to such a configuration, whether a person or an item has been left behind can be more accurately determined as compared to the case where the determination is made only by the record of opening and closing of the rear door or the result of sensing to the inside of the vehicle cabin. 
     The information processing device according to the present disclosure may be characterized in that the predetermined period before running of the vehicle is a period from when the vehicle is unlocked until the vehicle starts to move and the predetermined period after running of the vehicle is a period from when the vehicle is stopped until the vehicle is locked. 
     The information processing device according to the present disclosure may be characterized in that the control unit presumes that a person or an item has been left behind in the rear seat of the vehicle when the rear door was opened and closed in the predetermined period before running of the vehicle but the rear door was not opened and closed in the predetermined period after running of the vehicle. This is because, in this case, it is suspected that a person or an item has been left behind in the rear seat. 
     The information processing device according to the present disclosure may be characterized in that the control unit performs sensing of the rear seat using a seat sensor mounted in the vehicle. The seat sensor may be a sensor that detects the load applied to the seating surface such as the weight of an occupant, or may be a sensor that detects whether a seat belt has been fastened. 
     The information processing device according to the present disclosure may be characterized in that the control unit performs sensing of the rear seat using a camera that captures an image of inside of the vehicle. For example, whether there is a person or an item in the vehicle can be detected based on the image acquired from the camera. 
     The information processing device according to the present disclosure may be characterized in that the control unit determines whether there is a person in the rear seat based on the sensing result. This is because the degree of urgency may vary depending on whether the object detected in the rear seat is a person or an item. 
     The information processing device according to the present disclosure may be characterized in that the control unit gives a first notification using a terminal associated with the user and gives a second notification using other means when there is no response to the first notification within a predetermined period. The first notification and the second notification may be sent to different destinations or may be given by different means or methods. With such a configuration, it is possible to more reliably notify an outside that a person or an item has been left behind. 
     The information processing device according to the present disclosure may be characterized in that the control unit gives the second notification when the control unit determines that there is a person in the rear seat. The information processing device according to the present disclosure may be characterized in that the control unit acquires information on a temperature inside a vehicle cabin of the vehicle, and gives the second notification when there is a person in the rear seat and the temperature inside the vehicle cabin of the vehicle is higher than a predetermined value. That is, the second notification may be given when the degree of urgency is high. 
     The information processing device according to the present disclosure may be characterized in that the control unit gives the second notification by operating an alarm of the vehicle. The information processing device according to the present disclosure may be characterized in that the control unit sends data for giving the second notification to a center server that manages the vehicle. With such a configuration, it is possible to more reliably notify an outside that a person or an item has been left behind even when the driver of the vehicle does not notice it. 
     The information processing device according to the present disclosure may be characterized in that the control unit gives a first notification when the control unit determines that there is no person in the rear seat, and gives a second notification by a method different from the first notification when the control unit determines that there is a person in the rear seat. That is, when the detected object is a person, a notification may be given by a method or means different from usual or may be sent to a destination different from usual. 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The configurations of the following embodiments are illustrative, and the present disclosure is not limited to the configurations of the embodiments. 
     First Embodiment 
     An overview of a vehicle system according to a first embodiment will be described with reference to  FIG. 1 . The vehicle system according to the present embodiment includes an in-vehicle device  100 , a vehicle platform  200 , and a user terminal  300 . The in-vehicle device  100  is an example of the “information processing device.” The in-vehicle device  100  and the vehicle platform  200  are mounted on the same vehicle  10 . 
     The in-vehicle device  100  is a computer mounted on the vehicle  10 . The in-vehicle device  100  has a function to determine that a person or an item has been left behind in the rear seat after the vehicle  10  is parked, based on information acquired from the vehicle platform  200  that will be described later. The in-vehicle device  100  also has a function to notify the user terminal  300  that will be described later based on the determination result. 
     The vehicle platform  200  is a platform including a plurality of computers that controls the vehicle  10 . The user terminal  300  is a mobile terminal carried by an occupant of the vehicle  10 . 
     Next, components of the system will be described in detail. The in-vehicle device  100  can be configured by a general-purpose computer. That is, the in-vehicle device  100  can be configured as a computer including a processor such as central processing unit (CPU) or graphics processing unit (GPU), a main storage device such as random access memory (RAM) or read-only memory (ROM), and an auxiliary storage device such as erasable programmable read-only memory (EPROM), hard disk drive, or removable medium. 
     The auxiliary storage unit stores an operating system (OS), various programs, various tables, etc. The processor executes the stored programs. It is thus possible to implement each function matching a predetermined purpose as will be described later. Part or all of the functions may be implemented by a hardware circuit such as application-specific integrated circuit (ASIC) or field-programmable gate array (FPGA). 
       FIG. 2  is a block diagram schematically showing an example of the configurations of the in-vehicle device  100  and the vehicle platform  200  shown in  FIG. 1 . The in-vehicle device  100  includes a control unit  101 , a storage unit  102 , a communication unit  103 , and a vehicle communication unit  104 . 
     The control unit  101  controls the in-vehicle device  100 . The control unit  101  is composed of, for example, an information processing unit such as CPU or GPU. The control unit  101  has a state determination unit  1011  and an alarm unit  1012  as functional modules. Each functional module may be implemented by the CPU executing a program stored in storage means such as ROM. 
     The state determination unit  1011  makes a determination regarding the state of the vehicle  10 .  FIG. 3  is a state transition diagram of the vehicle  10  according to the present embodiment. As shown in  FIG. 3 , the vehicle  10  according to the present embodiment can be in one of three predefined states. An example of the three predefined states is a “parked state,” a “stopped state,” and a “running state.” The vehicle  10  can be in the “parked state” when the vehicle  10  is parked and occupants are away from the vehicle  10 . Specifically, the vehicle  10  can be in the “parking state” when the engine or system power of the vehicle  10  is off and the doors of the vehicle  10  are locked. The vehicle  10  can be in the “stopped state” when the vehicle  10  is stopped (speed is 0 km/h) with the engine running (or with the system power on) or with the doors not locked. The vehicle  10  can be in the “running state” when the vehicle  10  is running (moving). That is, the vehicle  10  can be in the “running state” when the speed of the vehicle  10  is not 0 km/h. 
     The state determination unit  1011  monitors the state of the vehicle  10  based on information (e.g., the operating state of the engine, the lock state of the doors, the vehicle speed, etc.) acquired from the vehicle platform  200  that will be described later. When the state of the vehicle  10  has changed, the state determination unit  1011  records the state change of the vehicle  10  as vehicle data in the storage unit  102  that will be described later. The state determination unit  1011  monitors for door of the vehicle  10  opening and closing events. When any of the doors is opened and closed, the state determination unit  1011  records the door opening and closing event as the vehicle data. Whether a door opening and closing event has occurred can be determined based on the information acquired from the vehicle platform  200  that will be described later. The recorded vehicle data is used by the alarm unit  1012  that will be described later. 
     The alarm unit  1012  presumes that a person (e.g., an infant) or an item in the rear seat has been left behind, based on the vehicle data recorded by the state determination unit  1011 . For example, when there is a record that the rear door was opened and closed after transition from the parked state to the stopped state but there is no record that the rear door was opened and closed before transition from the stopped state to the parked state, the alarm unit  1012  can presume that a person or an item has been left behind. 
     When the alarm unit  1012  presumes that a person or an item has been left behind, the alarm unit  1012  senses the inside of a vehicle cabin of the vehicle  10  to check whether there is a person or an item in the vehicle cabin. The sensing can be performed using a sensor (that will be described later) provided in the vehicle  10 . For example, a seat sensor is mounted in the rear seat of the vehicle  10 . In this case, whether there is a person or an item in the rear seat of the vehicle  10  can be detected based on data output from the seat sensor. The vehicle  10  is equipped with, for example, a camera that captures an image of the inside of the vehicle  10 . In this case, whether there is a person or an item in the rear seat of the vehicle  10  can be detected based on image data. The alarm unit  1012  sends data notifying that a person or an item has been left behind (hereinafter referred to as notification data) to the user terminal  300  according to the sensing result. The notification data may include information obtained as a result of the sensing (e.g., an image of the inside of the vehicle  10 ). 
     The storage unit  102  is means for storing information and is composed of a storage medium such as RAM, magnetic disk, or flash memory. The storage unit  102  stores various programs to be executed by the control unit  101 , data to be used by the programs, etc. The storage unit  102  also stores data recording the state of the vehicle  10  and the rear door opening and closing events (vehicle data described above). 
     The vehicle data stored in the storage unit  102  will be described.  FIG. 4  is an example of the vehicle data stored in the storage unit  102 . In the present embodiment, the state determination unit  1011  generates a new record when the state of the vehicle  10  has transitioned and when a door opening and closing event has occurred. The new record generated is added to the vehicle data. As shown in the figure, the vehicle data includes fields indicating the date, time, state of the vehicle  10 , whether a door opening and closing event has occurred, and door number. 
     The “date” and “time” fields store data indicating the date and time the record was generated. The “vehicle state” field stores the status of the vehicle  10  at the time the record was generated. For example, when the state of the vehicle  10  has transitioned from the “parked state” to the “stopped state,” a record that the “vehicle state” is the “stopped state” is generated. 
     The “door opening and closing event” field stores data indicating whether a door opening and closing event has occurred. The “door number” field stores the numbers uniquely assigned to the individual doors of the vehicle  10  (see  FIG. 5 ). 
     By referring to these records, the alarm unit  1012  can determine whether a door opening and closing event occurred in the period from when the doors of the vehicle  10  were unlocked until the vehicle  10  started to move, and whether a door opening and closing event occurred in the period from when the vehicle  10  was stopped until the doors of the vehicle  10  were locked. 
     For example, a plurality of records indicated by sign  601  in  FIG. 4  means that the vehicle  10  transitioned from the parked state to the stopped state, the door  1  was then opened and closed, and thereafter the vehicle  10  transitioned to the running state. A plurality of records indicated by sign  602  in  FIG. 4  means that the vehicle  10  transitioned from the running state to the stopped state, the door  1  was then opened and closed, and thereafter the vehicle  10  transitioned to the parked state. 
     The communication unit  103  is an interface that wirelessly communicates with the user terminal  300 . The communication unit  103  can communicate with the user terminal  300  by using, for example, a mobile communication network, a wireless local area network (LAN), Bluetooth (registered trademark), etc. 
     The vehicle communication unit  104  is an interface unit that communicates with the vehicle platform  200 . The vehicle communication unit  104  is configured to communicate with a plurality of electronic control units (ECUs) and a sensor included in the vehicle platform  200  via an in-vehicle network. 
     The vehicle platform  200  is a platform including a plurality of computers that controls the vehicle  10 . The vehicle platform  200  includes one or more computers that control the vehicle  10 , such as an engine ECU  201  and a body ECU  202 . The engine ECU  201  is a computer that performs fuel injection control, ignition control, intake and exhaust control, etc. The engine ECU  201  may also perform control for a power train. In the present embodiment, the engine ECU  201  can acquire information on the operating state of the vehicle  10  (the operating state of the engine and the system power) and the speed of the vehicle  10 . 
     The body ECU  202  is a computer that controls locking and unlocking of the doors and other electrical components etc. of the vehicle  10 . In the present embodiment, the body ECU  202  can acquire information on opening and closing of the doors of the vehicle  10  and the lock state of the doors of the vehicle  10 .  FIG. 5  shows an example of the doors of the vehicle  10 . The vehicle  10  described in the present embodiment has four doors  1  to  4 . The door  3  and the door  4  are the doors (rear doors) to access the rear seat. The body ECU  202  can acquire information on opening and closing of the doors and the lock state of the doors. 
     The vehicle platform  200  further includes a sensor  203 . The sensor  203  includes one or more sensors that sense the inside of the vehicle cabin. An example of the sensor that senses the inside of the vehicle cabin is a seat sensor. The seat sensor is mounted in each of a plurality of seats of the vehicle  10  and can output sensor data indicating the load being applied to the seating surface of the seat. Another example of the sensor that senses the inside of the vehicle cabin is an image sensor. The image sensor is configured to capture an image of the inside of the vehicle cabin. 
     Next, the user terminal  300  will be described with reference to  FIG. 6 . The user terminal  300  is a mobile computer carried by an occupant of the vehicle  10 . The user terminal  300  includes a control unit  301 , a storage unit  302 , a communication unit  303 , and an input and output unit  304 . 
     The control unit  301  is means for controlling the user terminal  300 . The control unit  301  is composed of, for example, an information processing unit (processor) such as CPU. The control unit  301  may implement these functions by executing programs stored in the storage unit  302  that will be described later by the CPU. 
     The control unit  301  includes a notification unit  3011  as a functional module. This functional module may be implemented by the CPU executing a program stored in storage means (such as ROM). 
     The notification unit  3011  generates a notification that a person or an item has been left behind in the rear seat, based on the notification data received from the in-vehicle device  100 . The notification is output via the input and output unit  304 . For example, the notification can be given by voice or image. 
     The storage unit  302  is means for storing information and is composed of a storage medium such as RAM, magnetic disk, or flash memory. The storage unit  302  stores various programs to be executed by the control unit  301 , data to be used by the programs, etc. 
     The communication unit  303  is communication means for wirelessly communicating with the in-vehicle device  100 . The communication unit  303  wirelessly communicates with the in-vehicle device  100  by means similar to that of the communication unit  103 . 
     The input and output unit  304  is means for receiving an input operation performed by a user and presenting information to the user. Specifically, the input and output unit  304  is composed of a touch panel, control means for the touch panel, a liquid crystal display, and control means for the liquid crystal display. In the present embodiment, the touch panel and the liquid crystal display are provided as a single touch panel display. The input and output unit  304  may have a speaker etc. that outputs audio. 
     Next, processes that are performed by the components of the system will be described in detail.  FIG. 7  is a flowchart of a process that is performed by the in-vehicle device  100 . The illustrated process is performed by the control unit  101 . 
     First, in step S 11 , the state determination unit  1011  determines whether the doors of the vehicle  10  have been unlocked. Whether the doors of the vehicle  10  have been unlocked can be determined based on information acquired from the body ECU  202 . When YES in step S 11 , the process proceeds to step S 12 . When NO in step S 11 , the process returns to the initial state. In step S 12 , the state of the vehicle  10  is caused to transition to the “stopped state,” and a new record is added to the vehicle data. 
     In step S 13 , the state determination unit  1011  monitors for a door opening and closing event based on the information acquired from the body ECU  202 . When any of the doors is opened and closed in the stopped state, a new record indicating the door opening and closing event is added to the vehicle data. 
     In step S 14 , the state determination unit  1011  determines whether the vehicle  10  has started to move. Whether the vehicle  10  has started to move can be determined based on information acquired from the engine ECU  201 . When YES in step S 14 , the process proceeds to step S 15 . In step S 15 , the state of the vehicle  10  is caused to transition to the “running state,” and a new record is added to the vehicle data. 
     When the state of the vehicle  10  is the “running state,” the state determination unit  1011  monitors the speed of the vehicle  10  based on the information acquired from the engine ECU  201 . When it is determined that the vehicle  10  has stopped based on the speed of the vehicle  10  (step S 16 , YES), the process returns to step S 12 . That is, the state of the vehicle  10  is caused to transition to the “stopped state,” and a new record is added to the vehicle data. When the vehicle  10  is running (step S 16 , NO), the state determination unit  1011  continues to monitor the speed of the vehicle  10 . 
     When NO in step S 14 , the process proceeds to step S 17 . In step S 17 , the state determination unit  1011  determines whether the engine of the vehicle  10  has been stopped and the doors of the vehicle  10  have been locked. Whether the engine of the vehicle  10  has been stopped can be determined based on the information acquired from the engine ECU  201 . Whether the doors of the vehicle  10  have been locked can be determined based on the information acquired from the body ECU  202 . When NO in step S 17 , the process returns to step S 13 . 
     When YES in step S 17 , the process proceeds to step S 18 . In step S 18 , the state of the vehicle  10  is caused to transition to the “parked state,” and a new record is added to the vehicle data. 
     In step S 19 , a process regarding alarm is performed based on the latest vehicle data. It is determined whether a person or an item has been left behind in the vehicle  10 . When it is determined that a person or an item has been left behind in the vehicle  10 , notification data is sent to the user terminal  300 . 
     The process that is performed in step S 19  will be described in more detail with reference to  FIG. 8 .  FIG. 8  is a flowchart illustrating in detail the process that is performed in step S 19 . First, in step S 21 , the alarm unit  1012  acquires the vehicle data stored in the storage unit  102 . Next, in step S 22 , the alarm unit  1012  determines whether the rear door was opened and closed before the vehicle  10  started to move, based on the vehicle data. This determination is made by the following procedure.
     (1) Extract two latest records indicating that the state of the vehicle  10  has transitioned from the parked state to the stopped state and then to the running state.   (2) Determine whether there is a record of an opening and closing event of the rear door between the times corresponding to these records.
 
When YES in step S 22 , the process proceeds to step S 23 . When NO in step S 22 , the process of step S 19  ends.
   

     In step S 23 , the alarm unit  1012  determines whether the rear door was opened and closed before the vehicle  10  was parked, based on the vehicle data. Specifically, when the vehicle data includes a record satisfying the following conditions, it is determined that the rear door was opened and closed after the vehicle  10  was parked. This determination is made by the following procedure.
     (1) Extract two latest records indicating that the state of the vehicle  10  has transitioned from the running state to the stopped state and then to the parked state.   (2) Determine whether there is a record of an opening and closing event of the rear door between the times corresponding to these records.
 
When NO in step S 23 , the process proceeds to step S 24 . When YES in step S 23 , the process of step S 19  ends.
   

     In step S 24 , the alarm unit  1012  senses the inside of the vehicle cabin. When the process proceeds to step S 24 , it can be said that it is suspected that a person or an item has been left behind in the rear seat. In this case, the alarm unit  1012  senses the inside of the vehicle cabin to detect a person or an item in the rear seat. 
     The process that is performed in step S 24  will be described in more detail with reference to  FIG. 9 .  FIG. 9  is a flowchart illustrating in detail the process that is performed in step S 24 . First, in step S 31 , the alarm unit  1012  acquires sensor data from the sensor  203  in the vehicle  10 . For example, a seat sensor is mounted in the rear seat of the vehicle  10 . In this case, whether there is a person or an item in the rear seat of the vehicle  10  can be determined based on data output from the seat sensor. The vehicle  10  is equipped with a camera that captures an image of the inside of the vehicle  10  as an image sensor. In this case, whether there is a person or an item in the rear seat of the vehicle  10  can be determined based on image data captured by the camera. 
     In step S 32 , the alarm unit  1012  determines whether there is a person or an item in the rear seat. When YES in step S 32 , the process proceeds to step S 33 . In step S 33 , the alarm unit  1012  sends notification data to the user terminal  300 . When the notification data is received by the user terminal  300 , the notification unit  3011  generates a notification and outputs the notification via the input and output unit  304 . For example, the notification can be given by vibration of a vibrator, audio output, image output, etc. When NO in step S 32 , the process of step S 24  ends. 
     As described above, the in-vehicle device  100  according to the first embodiment presumes that a person or an item has been left behind in the rear seat, based on whether the rear door was opened and closed before the vehicle  10  started to move and whether the rear door was opened and closed after the vehicle  10  finished moving. When it is suspected that a person or an item has been left behind, sensing of the inside of the vehicle  10  is performed using the sensor. Accuracy of detection of whether a person or an item has been left behind can be improved by using both the determination based on opening and closing of the rear door and the determination using the sensor. 
     Second Embodiment 
     In the first embodiment, the in-vehicle device  100  sends notification data to the user terminal  300 , and the user terminal  300  having received the notification data generates a notification for the user. In a second embodiment, when the user does not respond to the notification, the in-vehicle device  100  gives another notification by means other than the user terminal  300 . 
       FIG. 10  is a flowchart of the process of step S 24  in the second embodiment. Since steps S 31 , S 32 , and S 33  shown by dashed lines are similar to those of the first embodiment, description thereof will be omitted. In the second embodiment, the alarm unit  1012  checks whether there is a response from the user after sending the notification data to the user terminal  300 . The user terminal  300  having received the notification acquires the response indicating an acknowledgement of the notification from the user. When the user terminal  300  obtains the response from the user, the user terminal  300  sends data that there is the response to the in-vehicle device  100 . When there is no response from the user (including the case of a time-out), the user terminal  300  sends data that there is no response to the in-vehicle device  100 . 
     In step S 34 , the alarm unit  1012  determines whether there is a response from the user. When there is no response, the process proceeds to step S 35 , and the in-vehicle device  100  gives another notification by other means (that is, by means other than the user terminal  300 ). This notification is referred to as a second notification. When there is a response from the user, the process of step S 24  ends. For example, other means may be a center server that manages the system. In this case, the in-vehicle device  100  may generate notification data indicating that the subject user does not respond, and may send the notification data to the center server. As a result, for example, an administrator of the center server can contact the user, unlock the doors of the vehicle  10 , open the windows of the vehicle  10 , etc. Equipment mounted in the vehicle  10  may be used as other means. For example, the in-vehicle device  100  can operate an alarm or light (e.g., hazard lights etc.) mounted on the vehicle  10  via the vehicle platform  200 . As a result, it is possible to notify people around the vehicle  10  that a person or an item has been left behind. 
     As described above, according to the second embodiment, when there is no response from the user, another notification is given by other means. This configuration makes it possible to notify a third party that a person or an item has been left behind more reliably. 
     Third Embodiment 
     In the second embodiment, when there is no response to the notification from the user, another notification (second notification) is given by other means. When the degree of urgency is low, it may be suitable to restrain the second notification from being given. In view of this, in a third embodiment, the second notification is restrained from being given when there is no person left behind in the vehicle  10 . 
       FIG. 11  is a flowchart of the process of step S 24  in the third embodiment. Since steps S 31 , S 32 , S 33 , S 34 , and S 35  shown by dashed lines are similar to those of the second embodiment, description thereof will be omitted. In the third embodiment, when it is determined that there is no response to the notification from the user, it is determined in step S 34 A whether a person has been detected in the vehicle  10 . For example, when sensing is performed using a weight sensor mounted in the seat of the vehicle  10 , whether there is a person in the vehicle  10  can be determined by determining whether the weight is greater than a threshold (e.g., 5 kg). When a sensor that acquires data on whether a seat belt has been fastened is used, it can be determined that there is a person in the vehicle  10  when the seat belt of the rear seat has been fastened. When sensing is performed using a camera that captures an image of the inside of the vehicle cabin of the vehicle  10 , whether there is a person in the vehicle  10  can be determined based on the image analysis result. For example, when a face is detected from the captured image, it can be determined that there is a person in the vehicle  10 . It may be determined that there is a person in the vehicle  10  when motion is detected based on continuously acquired images. 
     In the third embodiment, the process of step S 35  is performed only when a person is detected in the vehicle  10 . This configuration restrains an alarm (second notification) from being given due to an item left behind in the vehicle  10 . 
     Fourth Embodiment 
     In the third embodiment, the second notification is given on condition that a person remains in the vehicle  10 . However, it is also possible that the driver has left the vehicle  10  and a passenger is waiting in the vehicle  10 . In view of this, in a fourth embodiment, whether the second notification should be given is determined based further on the temperature inside the vehicle  10 . 
       FIG. 12  is a flowchart of the process of step S 24  in the fourth embodiment. Since steps S 31 , S 32 , S 33 , S 34 , S 34 A, and S 35  shown by dashed lines are similar to those of the third embodiment, description thereof will be omitted. In the fourth embodiment, when it is determined that there is no response to the notification from the user, information on the temperature inside the vehicle cabin of the vehicle  10  (temperature information) is acquired after step S 34 A (step S 34 B). For example, the temperature information can be acquired via the body ECU  202 . When the sensor  203  includes a temperature sensor, the temperature information may be acquired directly from the sensor  203 . In step S 34 C, it is determined whether the temperature inside the vehicle cabin is higher than a threshold, based on the acquired temperature information. When the temperature inside the vehicle cabin is higher than the threshold (e.g., 35 degrees Celsius), the process proceeds to step S 35 . 
     As described above, in the fourth embodiment, the process of step S 35  is performed only when there is a person in the vehicle  10  and the temperature inside the vehicle cabin is high. This makes it possible to given an alarm only when the inside of the vehicle  10  is in a dangerous condition. 
     Fifth embodiment 
     In the second to fourth embodiments, a notification is first sent to the user terminal  300 , and when there is no response, a second notification is given by other means. A fifth embodiment is an embodiment in which different notification methods are used depending on whether the object detected in the vehicle  10  is a person or an item. 
       FIG. 13  is a flowchart of the process of step S 24  in the fifth embodiment. Since steps S 31  and S 32  shown by dashed lines are similar to those of the first embodiment, description thereof will be omitted. In the fifth embodiment, when it is determined in step S 32  that there is a person or an item in the rear seat, it is further determined whether the detected object is a person or an item (step S 34 D). As described in the third embodiment (step S 34 ), this determination can be made based on the sensor data acquired by the seat sensor, the image acquired by the camera, etc. 
     When it is determined in step S 34 D that an item has been left behind in the rear seat, the process proceeds to step S 36 , and a notification is given by a first method. When it is determined in step S 34 D that a person has been left behind in the rear seat, the process proceeds to step S 37 , and a notification is given by a second method. 
     The first method and the second method may use different means for giving a notification. For example, when the first method is a method in which a notification is output via the user terminal  300 , the second method may be a method in which a notification is output via the alarm of the vehicle  10 . For example, when the first method is a method in which the vibrator of the user terminal  300  is vibrated, the second method may be a method in which audio is output from the user terminal  300 . 
     The notification data may be sent to different destinations between the first method and the second method. For example, when the first method is a method in which notification data is sent to the user terminal  300 , the second method may be a method in which notification data is sent to the center server. 
     In the fifth embodiment, a notification is given by the second method when a person has been left behind in the rear seat. In the fourth embodiment, whether a notification is given by the first method or the second method may be selected based further on the temperature inside the vehicle cabin. For example, as shown in  FIG. 14 , the step of determining the temperature inside the vehicle cabin (steps S 34 B and S 34 C) may be added after step S 34 D, and a notification may be given by the second method only when the temperature inside the vehicle cabin is high. 
     Modifications 
     The above embodiments are merely illustrative, and the present disclosure may be modified as appropriate without departing from the spirit and scope of the present disclosure. 
     For example, the processes and means described in the present disclosure can be combined as desired as long as no technical contradiction occurs. 
     In the description of the embodiments, the in-vehicle device mounted on the vehicle is illustrated as an information processing device. However, the illustrated functions may be performed by a device provided outside the vehicle (hereinafter referred to as the external device, typically a server device etc.). In this case, the vehicle platform  200  may send various kinds of data (opening and closing of the doors, speed, operating state, etc.) to the external device, and the external device may perform the functions illustrated in the present specification based on the received data. 
     The processes described as being performed by one device may be allocated to and performed by a plurality of devices. Alternatively, the processes described as being performed by different devices may be performed by one device. The type of hardware configuration (server configuration) that is used to implement each function in the computer system can be flexibly changed. 
     The present disclosure can also be implemented by supplying computer programs implementing the functions described in the above embodiments to a computer, and causing one or more processors of the computer to read and execute the programs. Such computer programs may be provided to the computer by a non-transitory computer-readable storage medium that can be connected to a system bus of the computer, or may be provided to the computer via a network. Examples of the non-transitory computer-readable storage medium include: any type of disk such as magnetic disk (floppy (registered trademark) disk, hard disk drive (HDD), etc.) and optical disk (compact disc (CD)-ROM, digital versatile disc (DVD), Blu-ray disc, etc.); a read only memory (ROM); a random access memory (RAM); an erasable programmable ROM (EPROM); an electrically erasable programmable ROM (EEPROM); a magnetic card; a flash memory; an optical card; and any type of medium suitable for storing electronic instructions.