Patent Description:
There has been proposed an accident notifying system that, if an accident occurs in a mobile object such as a vehicle, automatically notifies the occurrence of the accident to a server. In this accident notifying system, for example, a terminal device mounted in a vehicle detects impact occurring in the vehicle and determines based on the detected magnitude of the impact (impact value) whether an accident has occurred. And if determining that an accident has occurred, the terminal device notifies the fact of accident occurrence and the site of occurrence of the accident to an external server via radio communication (e.g., Patent Document <NUM>).

In the above conventional technique, when impact above or at a certain level is detected, it is uniformly determined that an accident has occurred and is notified, and thus a so-called false notification reporting an accident, occurs in spite of no accident having actually occurred. For example, false notifications tend to increase on roads on which impact is likely to occur because of irregularities in the surface, the condition of a curve and inclination, and the like. In contrast, if the reference value (threshold) for impact values with which to determine as an accident is raised so that no false notification occurs, then there is the problem that accidents with weak impact cannot be notified as accidents.

It is the object of the invention to reduce false accident notifications from occuring in a large number.

This object is accomplished by the features an information processing device according to independent claim <NUM> and corresponding method and program claims according to independent claims <NUM> and <NUM>, respectively.

The same reference numerals are used to denote substantially the same or equivalent parts in the descriptions and accompanying drawings of the embodiments below.

<FIG> is a block diagram showing the configuration of an accident notifying system according to Embodiment <NUM>. The accident notifying system is composed of a server <NUM> and a plurality of terminal devices <NUM>-<NUM> to <NUM>-n (n is an integer of two or greater).

The terminal device <NUM>-<NUM> to <NUM>-n is, for example, a navigation device mounted in a mobile object such as a vehicle (hereinafter simply called a vehicle) and performs radio communication with the server <NUM>. The terminal devices <NUM>-<NUM> to <NUM>-n each have the same configuration, and hence the configuration of the terminal device <NUM>-<NUM> will be described below with description of the configurations of the terminal devices <NUM>-<NUM> to <NUM>-n being omitted.

The terminal device <NUM>-<NUM> has an output unit <NUM>, an impact detecting unit <NUM>, a position information acquiring unit <NUM>, an accident determining unit <NUM>, a notification generating unit <NUM>, an error determining unit <NUM>, a transmitting and receiving unit <NUM>, a storage unit <NUM>, and an erroneous-determination prone area approach determining unit <NUM>.

The output unit <NUM> is composed of a display section 11A and a voice output section 11B. The display section 11A is constituted by a display panel such as a liquid crystal display and has a function to display, e.g., buttons of a touch-panel type. The voice output section 11B is constituted by a voice output device such as a speaker.

The impact detecting unit <NUM> is constituted by, e.g., an acceleration sensor and detects the magnitude of impact occurring in the vehicle as an impact value G (hereinafter simply called an impact value) based on a change in acceleration of the vehicle.

The position information acquiring unit <NUM> is constituted by, e.g., a GPS (Global Positioning System) sensor and acquires position information indicating the current position of the vehicle. For example, the position information acquiring unit <NUM> receives radio waves transmitted from a plurality of GPS satellites and calculates the distance from each GPS satellite based on the received radio waves to acquire position information.

The accident determining unit <NUM> determines that an accident has occurred when the impact value detected by the impact detecting unit <NUM> is greater than or equal to a threshold.

The notification generating unit <NUM> generates an accident notification containing information about the impact value of detected impact and the travelling speed and position of the vehicle when the impact was detected according to accident determination by the accident determining unit <NUM>. Further, the notification generating unit <NUM> generates a withdrawal notification to withdraw the accident notification if the error determining unit <NUM> determines that the accident determination is false.

The error determining unit <NUM> determines whether accident determination by the accident determining unit <NUM> is false. For example, after the impact detecting unit <NUM> detects impact greater than or equal to the threshold, the error determining unit <NUM> determines whether the vehicle travels normally based on whether the vehicle travels a predetermined distance in a predetermined time and, when determining that the vehicle travels normally, determines that the accident determination is false.

Further, during a predetermined withdrawal acceptance time, the error determining unit <NUM> makes the display section 11A of the output unit <NUM> display a withdrawal button of a touch-panel type to accept the withdrawal of accident notification by the driver's judgement. If the withdrawal button is operated, the error determining unit <NUM> determines that the accident determination is false.

The transmitting and receiving unit <NUM> transmits the accident notification generated by the notification generating unit <NUM> to the server <NUM>. Further, after transmitting the accident notification to the server <NUM>, the transmitting and receiving unit <NUM> transmits a withdrawal notification to the server <NUM> if the error determining unit determines that the accident determination is false.

Further, the transmitting and receiving unit <NUM> receives information about the threshold of impact used in accident determination by the accident determining unit <NUM> and information about an erroneous-determination prone area from the server <NUM>.

The storage unit <NUM> stores a variety of information including information about the threshold of impact and the erroneous-determination prone area received by the transmitting and receiving unit <NUM>.

The erroneous-determination prone area approach determining unit <NUM> determines whether the vehicle is approaching the erroneous-determination prone area (that is, whether the vehicle will enter the erroneous-determination prone area within a predetermined reference time) based on information about the erroneous-determination prone area stored in the storage unit <NUM> and position information acquired by the position information acquiring unit <NUM>. Then the erroneous-determination prone area approach determining unit <NUM> makes the output unit <NUM> output the determining result.

Specifically, when determining that the vehicle is approaching the erroneous-determination prone area, the erroneous-determination prone area approach determining unit <NUM> makes, for example, a message to notify approaching the erroneous-determination prone area and to prompt the driver to notice ("An erroneous-determination prone area. meters ahead, please carefully travel. " or the like) be displayed on the screen of the display section 11A. Further, the erroneous-determination prone area approach determining unit <NUM> makes the voice output section 11B output a voice message corresponding to the message displayed by the display section 11A.

The server <NUM> includes a transmitting and receiving unit <NUM>, a notification accepting unit <NUM>, an accident processing unit <NUM>, an erroneous-determination prone area identifying unit <NUM>, a threshold calculating unit <NUM>, and a storage unit <NUM>.

The transmitting and receiving unit <NUM> transmits and receives information data to and from the terminal devices <NUM>-<NUM> to <NUM>-n and receives accident notifications and withdrawal notifications. Further, the transmitting and receiving unit <NUM> transmits information about the threshold of impact to be used in accident determination by the terminal devices <NUM>-<NUM> to <NUM>-n and the erroneous-determination prone area to the terminal devices <NUM>-<NUM> to <NUM>-n.

The notification accepting unit <NUM> accepts accident notifications and withdrawal notifications from the terminal devices <NUM>-<NUM> to <NUM>-n via the transmitting and receiving unit <NUM>. The notification accepting unit <NUM> acquires information about the detection position of impact and speed of the vehicle, and information about the impact value contained in an accident notification to store in the storage unit <NUM>.

If the notification accepting unit <NUM> accepts an accident notification and does not accept a withdrawal notification within a predetermined withdrawal time, then the accident processing unit <NUM> performs a process of establishing voice communication between the operator terminal (not shown) used by the operator and the terminal device which transmitted the accident notification, and a process of notifying accident occurrence with position information to a police station and a fire station (hereinafter collectively called an accident process). In the voice communication between the operator terminal and the terminal device, for example, questioning by the operator, the driver's response thereto, and the like are performed.

The erroneous-determination prone area identifying unit <NUM> identifies an area including many detection positions for which an accident notification was withdrawn as an erroneous-determination prone area based on information about the detection positions of impact contained in accident notifications (withdrawn accident notifications and not-withdrawn accident notifications) accepted by the notification accepting unit <NUM>. For example, the erroneous-determination prone area identifying unit <NUM>, for each area of a certain size (e.g., an area <NUM> meters square), calculates the proportion of the number of accident notifications withdrawn by withdrawal notifications to the number of accepted accident notifications as a withdrawal rate and identifies an area of a high withdrawal rate as an erroneous-determination prone area. Note that the erroneous-determination prone area identifying unit <NUM> does not calculate a withdrawal rate for an area where the number of accepted accident notifications is less than a predetermined reference value (that is, an area where the number of samples, accident notifications, is small) and does not identify the area as an erroneous-determination prone area.

The threshold calculating unit <NUM> calculates a reference value for impact values based on accident notifications and withdrawal notifications accepted by the notification accepting unit <NUM> and sets thresholds for impact that the terminal devices <NUM>-<NUM> to <NUM>-n use in accident determination.

<FIG> are diagrams schematically showing the relation between the travelling speed, impact value, and threshold. The hatched portions of the figures indicate ranges above or at a threshold (that is, ranges where it is determined that an accident occurs. In general, as the travelling speed of a vehicle becomes greater, impact occurring in the vehicle becomes greater, and hence the threshold of impact used in accident determination is determined according to the travelling speed in principle as shown in <FIG>. The threshold calculating unit <NUM> makes a change to this by a statistical technique so as to set a threshold of impact suitable for the area (that is, a threshold applied to each area).

If a predetermined number or greater of accident notifications are accepted by the notification accepting unit <NUM> and stored in the storage unit <NUM>, the threshold calculating unit <NUM> calculates an impact value as a reference based on impact values and travelling speeds contained in accident notifications to set a threshold for impact. For example, the threshold calculating unit <NUM> calculates a standard deviation for how impact values are distributed in a certain speed range to set a threshold for impact.

<FIG> is a diagram showing an example of how accident notifications (not-withdrawn accident notifications and withdrawn accident notifications) are distributed against the impact value and the travelling speed. The threshold calculating unit <NUM> sets a threshold for impact based on this distribution such that the smallest impact value (corresponding to the travelling speed) from among impact values contained in the not-withdrawn accident notifications is included in a region above or at the threshold (that is, a region where it is determined that an accident occurs) as shown in <FIG>.

The storage unit <NUM> accumulates and stores accident notifications and withdrawal notifications accepted by the notification accepting unit <NUM>, thresholds for impact set by the threshold calculating unit <NUM>, and information about erroneous-determination prone areas identified by the erroneous-determination prone area identifying unit <NUM>.

Next, the operation of accident notification processing executed by the server <NUM> and the terminal devices <NUM>-<NUM> to <NUM>-n will be described with reference to the flow charts of <FIG>. Note that description of the threshold calculation processing executed by the threshold calculating unit <NUM> of the server <NUM> is omitted.

First, a first processing operation executed by the terminal devices <NUM>-<NUM> to <NUM>-n will be described with reference to the flow chart of <FIG>. In the description below, one of the terminal devices <NUM>-<NUM> to <NUM>-n is also called simply the terminal device <NUM>.

The impact detecting unit <NUM> of the terminal device <NUM> determines whether impact greater than or equal to the threshold has been detected (step S101). If impact greater than or equal to the threshold has been detected, the accident determining unit <NUM> determines that an accident has occurred (step S102).

The notification generating unit <NUM> generates an accident notification containing position information indicating the position of the vehicle when impact was detected and information about the speed of the vehicle and the impact value of detected impact. The transmitting and receiving unit <NUM> transmits the accident notification generated by the notification generating unit <NUM> to the server <NUM> (step S103).

The error determining unit <NUM> determines whether the accident determination is false (step S104). Specifically, the error determining unit <NUM> determines that the accident determination is false if the vehicle has travelled a predetermined distance within a predetermined time or if the driver has operated the withdrawal button. On the other hand, if the vehicle has not travelled a predetermined distance and has stopped, and the withdrawal button has not been operated, then it is determined that the accident determination is not false.

If it is determined that the accident determination is not false, the terminal device <NUM> finishes the process. On the other hand, if it is determined that the accident determination is false, the notification generating unit <NUM> of the terminal device <NUM> generates a withdrawal notification to withdraw the accident notification. The transmitting and receiving unit <NUM> transmits the withdrawal notification to the server <NUM> (step S105).

Next, the processing operation of the server <NUM> will be described with reference to the flow chart of <FIG>.

The notification accepting unit <NUM> determines whether an accident notification has been accepted (that is, whether the transmitting and receiving unit <NUM> has received an accident notification) (step S201). If determining that an accident notification has been accepted, the notification accepting unit <NUM> determines whether a withdrawal notification has been accepted (that is, whether the transmitting and receiving unit <NUM> has received a withdrawal notification) within a predetermined time (step S202).

If determining that a withdrawal notification has not been accepted within the predetermined time, the notification accepting unit <NUM> supplies accident-notification acceptance information indicating that the accident notification has been accepted to the accident processing unit <NUM>. The accident processing unit <NUM> performs a predetermined accident process (step S203).

In contrast, if determining that a withdrawal notification has been accepted within the predetermined time, the notification accepting unit <NUM> withdraws the accepted accident notification (step S204).

The notification accepting unit <NUM> acquires information about the detection positions of impact, information about vehicle speeds, and information about impact values contained in accident notifications (that is, withdrawn accident notifications and not-withdrawn accident notifications) (step S205) and stores in the storage unit <NUM>.

The erroneous-determination prone area identifying unit <NUM> calculates the withdrawal rate of accident notifications in a predetermined range of area (e.g., an area <NUM> meters square) including detection positions based on information about the detection positions, vehicle speeds, and impact values of past accident notifications stored in the storage unit <NUM> (step S206).

The erroneous-determination prone area identifying unit <NUM> determines whether the calculated withdrawal rate is greater than or equal to a predetermined value (step S207). If the withdrawal rate is not greater than or equal to the predetermined value, the server <NUM> finishes the process. On the other hand, if determining that the withdrawal rate is greater than or equal to the predetermined value, the erroneous-determination prone area identifying unit <NUM> updates information about erroneous-determination prone areas stored in the storage unit <NUM>. The transmitting and receiving unit <NUM> transmits the updated information about erroneous-determination prone areas to the terminal devices <NUM>-<NUM> to <NUM>-n (step S208).

Apart from the process of steps S207 and S208, if the withdrawal rate in an area that has been an erroneous-determination prone area until now lowers to less than the predetermined value, the erroneous-determination prone area identifying unit <NUM> excludes that area from the erroneous-determination prone areas and updates information about the erroneous-determination prone areas stored in the storage unit <NUM>. The transmitting and receiving unit <NUM> transmits the updated information about the erroneous-determination prone areas to the terminal devices <NUM>-<NUM> to <NUM>-n.

Next, a second processing operation executed by the terminal devices <NUM>-<NUM> to <NUM>-n will be described with reference to the flow chart of <FIG>.

The transmitting and receiving unit <NUM> determines whether information about the erroneous-determination prone areas has been received from the server <NUM> (step S301). When determining that information about the erroneous-determination prone areas has been received, the unit <NUM> updates information about erroneous-determination prone areas stored in the storage unit <NUM> (step S302).

The erroneous-determination prone area approach determining unit <NUM> determines whether the vehicle will enter an erroneous-determination prone area within a predetermined reference time based on information about the erroneous-determination prone areas and current-position information acquired by the position information acquiring unit <NUM> (step S303).

If determining that the vehicle will not enter an erroneous-determination prone area within the predetermined reference time, the terminal device <NUM> finishes the process. On the other hand, if it is determined that the vehicle will pass through an erroneous-determination prone area within the predetermined reference time, the output unit <NUM> informs that the vehicle is approaching an erroneous-determination prone area (step S304). For example, the display section 11A displays a message indicating that the vehicle is approaching an erroneous-determination prone area and to call the driver's attention, and the voice output section 11B outputs a voice message corresponding to this.

As described above, in the accident notifying system of the present embodiment, a terminal device that has detected impact greater than or equal to the threshold transmits an accident notification to the server. Thereafter, the terminal device determines whether the accident determination is false, and, if determining being false, transmits a withdrawal notification to the server. The server updates information about erroneous-determination prone areas that designates areas where the withdrawal of an accident notification often happens based on received accident notifications and withdrawal notifications and transmits the updated information about erroneous-determination prone areas to the terminal devices.

In the accident notifying system of the present embodiment, the server can identify areas where the withdrawal of an accident notification often happens (that is, erroneous-determination prone areas) based on accident notifications and withdrawal notifications transmitted from the terminal devices. Thus, when an accident notification is made, the accident process can be appropriately performed based on information about erroneous-determination prone areas.

Further, the server calculates an impact value as a reference based on information about impact detection positions, vehicle speeds, and impact values, and the like contained in accident notifications (that is, withdrawn accident notifications and not-withdrawn accident notifications) and sets a threshold for impact to be used by the terminal device in accident determination. Thus, the threshold as a reference with which to determine an accident occurring can be changed according to the shape of the road, vehicle speed, and so on, so that erroneous determination of an accident can be prevented.

The terminal device receives information about erroneous-determination prone areas from the server. Thus, the driver who drives a vehicle having the terminal device mounted therein can drive avoiding large impact by lowering the speed or so on when passing through that area, based on information about erroneous-determination prone areas, so that erroneous determination of an accident can be prevented.

An accident notifying system of the present embodiment has substantially the same configuration as the accident notifying system of Embodiment <NUM> shown in <FIG> and is different in the operation of the notification generating unit <NUM> and transmitting and receiving unit <NUM> of the terminal devices <NUM>-<NUM> to <NUM>-n and the operation of the transmitting and receiving unit <NUM> and notification accepting unit <NUM> of the server <NUM> from the accident notifying system of Embodiment <NUM>.

The notification generating unit <NUM> generates an accident notification containing information about the impact value of detected impact and the travelling speed and position of the vehicle when the impact was detected in response to accident determination by the accident determining unit <NUM>. Further, the notification generating unit <NUM> generates an erroneous-determination notification indicating that an erroneous-determination was made if the error determining unit <NUM> determines that the accident determination is false. The erroneous-determination notification includes position information of the site where impact was detected, information about the speed of the vehicle, information about the impact value, and information indicating that the impact was not what was caused by an accident.

If the notification generating unit <NUM> has generated an accident notification, and the error determining unit has not determined that the accident determination is false within a predetermined time (e.g., <NUM> sec) (that is, if the accident determination has not been withdrawn), then the transmitting and receiving unit <NUM> transmits an accident notification to the server <NUM>.

On the other hand, if, after the accident determining unit <NUM> determines that an accident has occurred, the error determining unit <NUM> determines that the accident determination is false within the predetermined time, then instead of an accident notification an erroneous-determination notification is transmitted to the server <NUM>. That is, in the accident notifying system of the present embodiment, if the error determining unit <NUM> determines that the accident determination is false, an accident notification is not transmitted to the server <NUM>, and only an erroneous-determination notification is transmitted to the server <NUM>.

The transmitting and receiving unit <NUM> of the server <NUM> transmits and receives information data to and from the terminal devices <NUM>-<NUM> to <NUM>-n and receives accident notifications and erroneous-determination notifications. Note that the terminal devices <NUM>-<NUM> to <NUM>-n selectively transmit an accident notification or erroneous-determination notification according to the determination of the error determining unit <NUM>, so that the transmitting and receiving unit <NUM> of the server <NUM> receives one of an accident notification and erroneous-determination notification.

The notification accepting unit <NUM> accepts one of an accident notification and erroneous-determination notification from the terminal device <NUM>-<NUM> to <NUM>-n via the transmitting and receiving unit <NUM>. The notification accepting unit <NUM> acquires information about the detection position of impact and the speed of the vehicle, and information about the impact value contained in the accident notification or erroneous-determination notification and stores in the storage unit <NUM>.

The erroneous-determination prone area identifying unit <NUM> counts the number of erroneous determinations for each area of a certain size (e.g., an area <NUM> meters square) based on information about the detection positions of impact contained in erroneous-determination notifications stored in the storage unit <NUM>. Then the erroneous-determination prone area identifying unit <NUM> identifies an area where the number of erroneous determinations is greater than or equal to a predetermined number as an erroneous-determination prone area.

Next, the operation of accident notification processing executed by the server <NUM> and the terminal devices <NUM>-<NUM> to <NUM>-n of the present embodiment will be described with reference to the flow charts of <FIG>. Note that description of the threshold calculation processing executed by the threshold calculating unit <NUM> of the server <NUM> is omitted.

The impact detecting unit <NUM> of the terminal device <NUM> determines whether impact greater than or equal to the threshold has been detected (step S401). If impact greater than or equal to the threshold has been detected, the accident determining unit <NUM> determines that an accident has occurred (step S402). The notification generating unit <NUM> generates an accident notification containing position information indicating the position of the vehicle when impact was detected and information about the speed of the vehicle and the impact value of detected impact.

The error determining unit <NUM> determines whether the accident determination is false (step S403). The error determining unit <NUM> determines that the accident determination is false if the vehicle has travelled a predetermined distance within a predetermined time or if the driver has operated the withdrawal button. On the other hand, if the vehicle has not travelled a predetermined distance and has stopped and if the withdrawal button has not been operated, then it is determined that the accident determination is not false.

If it is determined that the accident determination is not false, the transmitting and receiving unit <NUM> transmits the accident notification generated by the notification generating unit <NUM> to the server <NUM> (step S404).

On the other hand, if it is determined that the accident determination is false, the notification generating unit <NUM> generates an erroneous-determination notification containing position information indicating the position of the vehicle when impact was detected, the speed of the vehicle, and the impact value of detected impact. The transmitting and receiving unit <NUM> transmits the erroneous-determination notification to the server <NUM> (step S405).

The notification accepting unit <NUM> determines whether an accident notification transmitted from the terminal device <NUM> has been accepted (that is, whether the transmitting and receiving unit <NUM> has received an accident notification) (step S501). If determining that an accident notification has been accepted, the notification accepting unit <NUM> supplies accident-notification acceptance information indicating that the accident notification has been accepted to the accident processing unit <NUM>. The accident processing unit <NUM> performs a predetermined accident process (step S502).

On the other hand, when determining that an accident notification has not been accepted, the notification accepting unit <NUM> determines whether an erroneous-determination notification has been accepted (that is, whether the transmitting and receiving unit <NUM> has received an erroneous-determination notification) (step S503).

When determining that an erroneous-determination notification has been accepted, the erroneous-determination prone area identifying unit <NUM> counts that erroneous-determination notification as an erroneous determination at the detection position based on information about the detection position contained in the erroneous-determination notification (step S504). The counted erroneous-determination notification is stored in the storage unit <NUM>.

The erroneous-determination prone area identifying unit <NUM> determines whether the number of erroneous determinations in a predetermined range of area (e.g., an area <NUM> meters square) including the detection position is greater than or equal to a predetermined number based on information about detection positions, vehicle speeds, and impact values of past erroneous-determination notifications stored in the storage unit <NUM> (step S505). If the number of erroneous determinations is less than the predetermined number, the server <NUM> finishes the process.

If the number of erroneous determinations is greater than or equal to the predetermined number, the erroneous-determination prone area identifying unit <NUM> updates information about erroneous-determination prone areas stored in the storage unit <NUM>. The transmitting and receiving unit <NUM> transmits the updated information about erroneous-determination prone areas to the terminal devices <NUM>-<NUM> to <NUM>-n (step S506).

The transmitting and receiving unit <NUM> determines whether information about the erroneous-determination prone areas has been received (step S601). When determining that information about the erroneous-determination prone areas has been received, the unit <NUM> updates information about erroneous-determination prone areas stored in the storage unit <NUM> (step S602).

The erroneous-determination prone area approach determining unit <NUM> determines whether the vehicle will enter an erroneous-determination prone area within a predetermined reference time based on information about the erroneous-determination prone areas and current-position information acquired by the position information acquiring unit <NUM> (step S603).

If determining that the vehicle will not enter an erroneous-determination prone area within the predetermined reference time, the terminal device <NUM> finishes the process. On the other hand, if it is determined that the vehicle will pass through an erroneous-determination prone area within the predetermined reference time, the output unit <NUM> informs that the vehicle is approaching an erroneous-determination prone area (step S604). For example, the display section 11A displays a message indicating that the vehicle is approaching an erroneous-determination prone area and to call the driver's attention, and the voice output section 11B outputs a voice message corresponding to this.

As described above, in the accident notifying system of the present embodiment, if a terminal device has detected impact greater than or equal to the threshold, the terminal device determines that an accident has occurred and generates an accident notification. Then the terminal device determines whether the determination that an accident has occurred is false, and, if determining not being false, transmits an accident notification and, if determining being false, transmits an erroneous-determination notification. The server updates information about erroneous-determination prone areas that designates areas where the erroneous determination of an accident notification often happens based on received accident notifications and erroneous-determination notifications and transmits the updated information about erroneous-determination prone areas to the terminal devices.

In the accident notifying system of the present embodiment, the server can identify areas where the withdrawal of an accident notification often happens (that is, erroneous-determination prone areas) based on accident notifications and erroneous-determination notifications transmitted from the terminal devices. Thus, when an accident notification is made, the accident process can be appropriately performed based on information about erroneous-determination prone areas. Further, the reference (e.g., the threshold for impact) with which the terminal device determines an accident happening can be changed based on information about erroneous-determination prone areas, so that erroneous determination of an accident can be prevented.

Further, the terminal device receives information about erroneous-determination prone areas from the server. Thus, the driver who drives a vehicle having the terminal device mounted therein can drive avoiding large impact by lowering the speed or so on when passing through that area, based on information about erroneous-determination prone areas, so that erroneous determination of an accident can be prevented.

Embodiments of the present invention are not limited to what are shown by the above embodiments. For example, in the above embodiments, description has been made taking as an example the case where an impact value (G) is detected based on a change in acceleration to determine whether an accident has occurred. However, the method of determining whether an accident has occurred is not limited to this. For example, it may be determined whether an accident has occurred based on a characteristic of sound of the impact when a vehicle suffers impact.

Further, in the above embodiments, as a means with which the output unit of the terminal device informs that the vehicle is approaching an erroneous-determination prone area, an example is described where the display section displays a message to inform that the vehicle is approaching an erroneous-determination prone area on the screen while the voice output section outputs it as a voice message. However, the output unit need not necessarily perform both screen display and voice output, and a method other than screen display and voice output may be used to inform.

Yet further, the above embodiment <NUM> describes an example where the erroneous-determination prone area identifying unit of the server <NUM> calculates the withdrawal rate of accident notifications to identify an erroneous-determination prone area. However, without the erroneous-determination prone area identifying unit calculating the withdrawal rate, an area where the number of withdrawals is large may be identified as an erroneous-determination prone area.

Still further, the above embodiment <NUM> describes an example where the erroneous-determination prone area identifying unit of the server <NUM> counts erroneous-determination notifications to identify an area where erroneous determination often happens as an erroneous-determination prone area. However, by calculating the proportion of erroneous-determination notifications to accident notifications, an area where the proportion of erroneous-determination notifications is high may be identified as an erroneous-determination prone area.

Claim 1:
An information processing device (<NUM>) comprising:
an accident notification accepting unit (<NUM>) configured to accept from a plurality of mobile objects an accident notification including site information indicating the site where impact greater than or equal to a threshold has occurred and a withdrawal notification for withdrawing said accident notification;
an area identifying unit (<NUM>), and
a transmitting unit (<NUM>),
characterized in that
the area identifying unit (<NUM>) is configured to identify a withdrawal prone area based on the site information included in the accident notification withdrawn by accepting said withdrawal notification;
the transmitting unit (<NUM>) is configured to transmit information about said withdrawal prone area to said plurality of mobile objects, and
said area identifying unit (<NUM>) is configured to calculate the proportion of the number of accident notifications withdrawn by said withdrawal notifications to the number of accident notifications accepted by said notification accepting unit (<NUM>) as a withdrawal rate for each area and to identify an area where said withdrawal rate is greater than or equal to a predetermined value as said withdrawal prone area,
wherein said accident notification includes an information about an impact value of the impact, and
wherein the information processing device comprises a threshold calculating unit (<NUM>) configured to correct said threshold for each area based on information about impact values and the site information contained in not-withdrawn accident notifications, and
wherein said transmitting unit (<NUM>) is configured to transmit said corrected threshold to said plurality of mobile objects.