Neighborhood creating device, neighborhood creating method, and computer-readable recording medium storing program

A neighborhood creating device includes: a memory; and one or more processors that execute a procedure in the memory, the procedure including a position acquiring process that acquires position information representing a position of a mobile object; a data creating process that creates mobile object data representing a condition associated with a movable range of the mobile object based on the position information; a data acquiring process that acquires obstacle data representing a condition associated with a place through which the mobile object is not able to move; and an information creating process that creates neighborhood information satisfying both conditions represented by the mobile object data and the obstacle data and continuously representing a movable range of the mobile object around the mobile object.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2012-121552 filed on May 29, 2012, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments discussed herein are related to a neighborhood creating device, a neighborhood creating method, and a computer-readable recording medium storing a program.

BACKGROUND

These days, services of displaying an indoor map on a mobile portable terminal and displaying a route from a present location to a desired location thereon have been suggested. For example, by installing a predetermined application, the present position can be displayed on a map of station premises displayed on a display unit of a mobile portable terminal and a route to a destination such as a toilet can be displayed thereon.

Techniques of calculating a distance between two points in consideration of a route through the use of a route network are also known. For example, a route search in consideration of gateways of facilities can be realized. In this case, a route search can be carried out in which a facility is provided with nodes and links in addition to normal nodes and links and gateways for connecting the inside and the outside of the facility are provided with nodes. Accordingly, in a route search in which a start point is outside the facility and a destination is inside the facility, it is possible to search for a route passing through the optimal gateway by seamlessly using the nodes and links.

In an inquiry method about a space, such as “feeds back an object within a range (target area) of a predetermined distance from a certain spot”, techniques of making an inquiry by designating a target area by the use of simple geometric shapes such as circles, rectangles, and polygons are known. These techniques are directed to, for example, analysis of land prices or criminal occurrence situations in a city. Accordingly, since the scale of a map to be used is relatively wide (at a block level) and the error of a global positioning system (GPS) is large, no particular problem occurs in the above-mentioned designation of a target area using the simple geometric shapes.

For example, Japanese Laid-open Patent Publication No. 2007-248472 is known as a technique according to the related art.

However, in the future, there is a possibility to upgrade route networks even in indoor places. When an indoor route network is provided along with a map, a route distance between spots in indoor places can be calculated. However, when a route distance between points not registered as spots is calculated, the use of a rout network is not realistic.

With the progress in technical development of positioning and the enhancement in precision of position information of a person in an indoor place, indoor maps as well as outdoor maps have been created and the precision of the maps have been enhanced. Accordingly, when it is considered that services in consideration of high-precision position information of a person are provided in a place such as an indoor place in which spatial structures are complicated, designation of a target area using simple shapes as in the related art frequently causes inconvenience.

For example, a service is assumed in which an alarm is rung when someone gets close to a person indoor. At this time, when the closeness is determined using a circular target area, the circle passes through a wall and thus a person present in a neighboring room may be extracted. In this case, an alarm is rung even when no one is present in the present room, and a feeling of wrongness is given to a user, which is erroneous determination. In this way, the area designating method in a spatial search simply allows only the area designation using fixed shapes such as circles, rectangles, and polygons, and an inquiry method about a space corresponding to high-precision position detection and high-precision maps is not provided yet.

SUMMARY

According to an aspect of the invention, a neighborhood creating device includes: a memory; and one or more processors that execute a procedure in the memory, the procedure including a position acquiring process that acquires position information representing a position of a mobile object; a data creating process that creates mobile object data representing a condition associated with a movable range of the mobile object based on the position information; a data acquiring process that acquires obstacle data representing a condition associated with a place through which the mobile object is not able to move; and an information creating process that creates neighborhood information satisfying both conditions represented by the mobile object data and the obstacle data and continuously representing a movable range of the mobile object around the mobile object.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a neighborhood creating system1according to a first embodiment will be described with reference to the accompanying drawings.FIG. 1illustrates the structure of the neighborhood creating system1according to the first embodiment. As illustrated inFIG. 1, the neighborhood creating system1includes a neighborhood creating device3, one or more portable terminals5-1, . . . ,5-n, and three or more local area network (LAN) access points (AP)9-1,9-2,9-3, . . . . The portable terminals5-1, . . . ,5-nare also collectively or representatively referred to as a portable terminal5. The APs9-1,9-2, . . . are also collectively or representatively referred to as an AP9. For example, the portable terminal5is connected to the neighborhood creating device3and a position estimating device7via a wireless communication network. A wireless communication network may include, for example, a mobile phone communication network and/or a communication network using a wireless LAN. A base station and/or an extension device connected to the base station may be referred to as an AP9. The portable terminal5and the AP9may be connected to each other, for example, via a wireless LAN. The neighborhood creating device3and the position estimating device7may be connected to each other, for example, via a wired communication network or a wireless communication network.

The neighborhood creating device3is a device creating the neighborhood of the portable terminal5based on the position of the portable terminal5and the peripheral map of the portable terminal5. For example, the neighborhood of the portable terminal5represents the predicted presence location of the portable terminal5after the present time point, that is, the latent movable range of the portable terminal5and represents a continuous distribution of numerical values on a plane in which the portable terminal5is present. The neighborhood area of a mobile object (the portable terminal5, for example) in this embodiment preferably spreads from the mobile object continuously along movable areas so as to avoid a non-movable place such as a wall. A potential is used to naturally express the shape of the neighborhood area.

The portable terminal5is a terminal device such as a portable information terminal and a mobile phone which is carried and moved, for example, persons11-1,11-2, . . . (hereinafter, collectively or representatively referred to as a person11). In this embodiment, the portable terminal5is described as an example of the mobile object. The portable terminal5includes a display unit5ahaving an input unit such as a touch panel, a wireless LAN receiver, a wireless receiver that receives information from the neighborhood creating device3, a control unit that controls an operation, and a storage unit. The portable terminal5enables to input information and enables to display information such as a map or a created neighborhood area.

The portable terminal5acquires identification of the APs9and information on the time to be consumed in communication by receiving communications from three or more APs9, and transmits the acquired information as information for estimating the position of the portable terminal5to the position estimating device7. The portable terminal5receives neighborhood information created from the neighborhood creating device3and presents the received neighborhood information. In this embodiment, an example is described where the neighborhood area of a person11is created by creating the neighborhood area of the portable terminal5.

The position estimating device7estimates the position of the portable terminal5based on the information acquired from the portable terminal5and transmits the estimated position to the neighborhood creating device3through a communication network. The position estimating device7is, for example, an arithmetic processing unit including a wireless communication unit.

The identification information of the respective APs9and the installation locations thereof are stored in the position estimating device7. The position estimating device7acquires the installation locations of the APs9by acquiring the identification information of the APs9, with which the portable terminal5communicates, from the portable terminal5and calculates the distances between the portable terminal5and the APs9by acquiring the times, which are consumed in the communication with the APs9, from the portable terminal5. The position estimating device7estimates the position of the portable terminal5from the locations of the APs9and the distances between the portable terminal5and three or more APs9. The estimation of the position may employ, for example, a three-point measurement method.

FIG. 2illustrates the functional structure of the neighborhood creating device3. As illustrated inFIG. 2, the neighborhood creating device3includes a position acquiring unit21, a neighborhood creating unit23, a wall data creating unit25, a map storage unit27, and an output unit30. The position acquiring unit21acquires the positional coordinates of the portable terminal5and the time at which the portable terminal5is present at that position as position information from the position estimating device7. The map storage unit27stores a map representing the periphery of the portable terminal5. The wall data creating unit25creates wall data representing conditions associated with locations through which a mobile object is not able to move based on the map storage unit27. Details of the wall data will be described later and include information on sample points and charge points based on the map.

The neighborhood creating unit23includes a mobile object data arranging unit31, a velocity calculating unit33, a range arranging unit35, a wall data storage unit37, a wall data acquiring unit39, a solution calculating unit41, and a potential generating unit43. The mobile object data arranging unit31arranges mobile object data representing conditions to be set in correspondence with the portable terminal5for the purpose of creating a neighborhood area based on the position information of the portable terminal5acquired by the position acquiring unit21. Details of the mobile object data will be described later and includes information on sample points and charge points based on the position of a mobile object.

The velocity calculating unit33calculates the moving velocity of the portable terminal5based on the position information of the portable terminal5acquired by the position acquiring unit21and the corresponding time information, for example, the difference between the position at the previous time and the present position. The velocity calculating unit33may calculate the moving direction of the portable terminal5.

The range arranging unit35determines a maximum range which serves as a calculation range when creating the neighborhood area of the portable terminal5, and arranges sample points and charge points to be described later based on the boundary of the maximum range. The maximum range may be, for example, expressed by a circle centered on the position of the mobile object. The radius of the circle may be determined, for example, depending on the moving velocity of the portable terminal5calculated by the velocity calculating unit33.

Although details will be described later, a charge simulation method is used to create the neighborhood area in this embodiment. In the charge simulation method, sample points and charge points are arranged and corresponding conditions are set. A sample point is a point at which a potential value is set as a condition for creating a continuous potential distribution in a plane in which the portable terminal5is present. The sample points are located on the boundary. That is, the sample points are located on the boundary between a wall and other spaces in case of the wall data, the sample points are located on a virtual boundary to be described later when they are based on the positions of the mobile object data, and the sample points are located on the boundary of the maximum range when they are based on the maximum range. A charge point is a point which is set as a point at which a potential is generated to correspond to a sample point. The wall data and the mobile object data are information including set potential values at one or more sample points, coordinates of the sample points, and coordinates of one or more charge points.

The wall data storage unit37stores the wall data created by the wall data creating unit25. The wall data acquiring unit39reads the wall data stored in the wall data storage unit37. The solution calculating unit41creates simultaneous equations based on the mobile object data, the maximum range, and the wall data and calculates the solutions thereof. The potential generating unit43generates a distribution of potentials of the neighborhood area of the portable terminal5based on the solutions calculated by the solution calculating unit41. The output unit30is, for example, a communication unit that outputs the result of the potential distribution generated by the neighborhood creating unit23.

A method of expressing the neighborhood area of a mobile object will be described below. A Laplace potential is most generally used as an expression of a potential. The Laplace potential may be expressed as a solution of a Laplace equation Δψ=0. The solution of the Laplace equation has the following features and advantages.

That is, the solution of the Laplace equation is continuously smooth and does not have an extremal value except for a maximum point. Therefore, it is suitable for naturally expressing a shape spreading from a mobile object to avoid a wall by creating a distribution in which the presence position of a person (mobile object) is the maximum and a wall surface is the minimum. Since the solution of the Laplace equation is a function of a position, a quantity (an altitude of potential) is present at a point on a map. This is a quantity decreasing with an increase in distance from the position of the mobile object (the center of the potential) and is thus suitable for use as an indicator of the distance from a mobile object in consideration of a route. The Laplace potential is used as the method of expressing a neighborhood area because of this advantage.

FIG. 3illustrates an example where the neighborhood of the portable terminal5is created using the Laplace potential.FIG. 3illustrates a neighborhood creation example50and a potential distribution58. In the neighborhood creation example50, potentials corresponding to the mobile object position55in a plane in which a wall51and a wall53are present are expressed by contours57-1to57-6. The potential distribution58expresses the potentials P three-dimensionally. In this way, through the neighborhood creation in this embodiment, the neighborhood area of the portable terminal5is expressed as a potential distribution continuously spreading to avoid untraversable areas such as the wall51and the wall53.

For example, when a service of ringing an alarm with the closeness of a person is provided using the neighborhood creation as described in this embodiment, it is requested that an alarm is rung within 1 second at the latest after a person gets close. Accordingly, it is desired to create a neighborhood area without any delay from the position information updated every moment through the positioning. However, the calculation of creating the Laplace potential generally takes much time.

In general, when numerically solving a partial differential equation, a space is divided into lattices and the calculation is performed. However, the Laplace equation is an elliptical partial differential equation and is not able to calculate the values of the lattices as positive values, and thus it is desired to solve large-scale simultaneous equations having the number of lattices formed through the division as a variable. This calculation takes much calculation time. For example, when the calculation of creating the potential of a single mobile object in an area which is vertically and horizontally divided into 100×100 parts (100×100=10,000 meshes) is performed, calculation time of about 1 minute is consumed in calculating the solutions of the simultaneous equations (for example, the operating frequency of the central processing unit is 2.8 GHz and an LU decomposition method is used for the solutions of the simultaneous equations). In order to express the neighborhood area distributed in a complicated indoor structure, it is easy to increase the number of meshes (spatial resolution). When it is considered that the neighborhood areas of plural mobile objects have to be calculated, the general lattice method takes excessive time and is not used well.

Therefore, in order to cope with a problem of the calculation time, the calculation of generating potentials is performed using a charge simulation method. By using the charge simulation method, the time of generating potentials in the order of minutes can be shortened to several milliseconds.

The charge simulation method is an approximate solution method of a partial differential equation. Since the charge simulation method is a simple algorithm, the charge simulation method has features that the calculation time consumed in acquiring an approximate solution is short and relatively-high approximation accuracy can be obtained for a smooth boundary. On the contrary, the charge simulation method has features that an error increases and application thereof is difficult when the boundary shape is complicated. The algorithm of the charge simulation method will be described below.

FIG. 4illustrates the charge simulation method. In the charge simulation method, as described above, sample points and charge points are determined. In the charge simulation method, the following processes are performed. (Process 1) An analysis area from which potentials are calculated is defined as an area Ω and sample points Xi (where i=1, 2, . . . , n; n is a natural number) are selected inside the area Ω. (Process 2) The potential values bi corresponding to the positions of the selected sample points Xi are designated. (Process 3) Charge points Yi (where i=1, 2, . . . , n; n is a natural number) are selected outside the area Ω. (Process 4) A solution u(X) is assumed to be the same as Equation 1 and coefficients Qi are determined to satisfy the conditions bi designated by u(Xi) through the use of Equation 2.

Here, |X-Yi| represents the distance between a sample point X and a charge point Yi.

In the charge simulation method, these simultaneous equations have to be solved. However, since the number of unknowns is smaller than that in the lattice solution method in the related art, the calculation time is considerably shortened. For example, a calculation consuming 58 millisecond (msec) or more in the lattice solution method with the number of meshes of 10,000 consumes 1 msec in the charge simulation method with the number of charge points of 60.

In the charge simulation method, by selecting several charge points and sample points along the boundary of a space to be analyzed, potentials are calculated which are smoothly distributed in the boundary and which satisfy the designated conditions on the boundary. By arranging the sample points and the corresponding charge points along the wall surfaces in the indoor map using this feature, the neighborhood creating device3generates a potential distribution that spreads along indoor traversable areas. In this embodiment, the sample points and the charge points are automatically arranged along the traversable area based on binary data, which has been generated from the indoor map data, representing the traversable area and the untraversable area.

FIGS. 5 and 6illustrate the arrangement of sample points and charge points based on the map data. As illustrated inFIG. 5, binary data95in which walls96are extracted from a map93is generated and wall data97including sample points98and charge points99is automatically arranged.

As illustrated inFIG. 6, the Operation of automatically arranging the charge points and the sample points from the binary data is as follows.

Operation 1: An outline105and an outline107of a wall101and a wall103which are untraversable areas as illustrated in an outline extraction example108are extracted from the binary data in which the wall101and the wall103are binarized as illustrated in a map100.

Operation 2: An image process (closing process) of causing the wall101and the wall103to slightly contract and acquiring a contracted area109and a contracted area111as illustrated in an area contraction example110is performed.

Operation 3: A contracted outline113and a contracted outline114are extracted from the contracted area109and the contracted area111of the contracted walls as illustrated in a contracted outline extraction example112. The contracted outline113and the contracted outline114are outlines which are present in the untraversable areas of the outline105and the outline107extracted in Operation 1.

Operation 4: Plural sample points117and plural sample points119are arranged at equal intervals along the outline105and the outline107as illustrated in a sample point arrangement example115.

Operation 5: Points are determined which are present closest to the sample points117and the sample points119arranged in Operation 4 and which are present on the inside contracted outline113or contracted outline114as illustrated in a charge point positioning method116, and plural charge points121and plural charge points123are arranged as illustrated in a charge point arrangement example120.

FIGS. 7A to 7Cillustrate examples where a potential distribution spreading from a mobile object is created. In the examples illustrated inFIGS. 7A to 7C, building walls54are present and a person11(portable terminal5) is present in the walls54. Since the charge simulation method is a solution to a boundary value problem, only values on the boundaries can be designated. For example,FIG. 7Aillustrates an example where a sample point45arranged on the boundary of the left wall54in the drawing (referred to as wall54afor the purpose of distinction) is bound to a potential of 1 and the sample point46arranged on the boundary of the right wall54in the drawing (referred to as wall54bfor the purpose of distinction) is bound to a potential of 0.FIG. 7Billustrates an example where the sample point47arranged on the boundary of the wall54ais bound to a potential of 0 and the sample point48arranged on the boundary of the wall54bis bound to a potential of 1.

On the other hand, the Laplace potential is distributed to monotonously increase (or decrease) between two boundary points. Accordingly, as illustrated inFIGS. 7A and 7B, a potential distribution having the presence position of a mobile object as an extremal value is not able to be created only by arranging the charge points and the sample points along the walls54of the building and designating the bound values.

Therefore, as illustrated inFIG. 7C, potentials centered on (maximized in) the mobile object position55are calculated. Accordingly, a virtual boundary59is provided to surround the mobile object position55, the value at the sample point63on the boundary is set to a maximum potential of 1, and the values at the sample points61on the walls54are set to a minimum potential of 0. By designating these conditions and performing the calculation, the potential distribution65spreading from the mobile object position55may be created.

FIG. 8illustrates an example where the sample points63and the charge points69surrounding the mobile object position55are arranged. As illustrated inFIG. 8, when it is assumed that each mesh in mobile object data130is a pixel131, several sample points63and several charge points69are arranged in the pixels around the mobile object position55to surround the mobile object position55.

FIG. 9illustrates an example of the arrangement of sample points and charge points. As illustrated inFIG. 9, in a space in which a wall54is present around a mobile object position55, plural sample points61are arranged on the boundary66of the wall54and charge points67corresponding to the sample points61are arranged by performing a closing process on the wall54. A virtual boundary59is arranged around the mobile object position55, and plural sample points63are arranged on the virtual boundary59. By performing a closing process on the virtual boundary59, charge points69corresponding to the sample points63are arranged. The sample points, the charge points, and the like included in the range71are made to move with the movement of the mobile object position55.

FIG. 10illustrates a function superposition example in the charge simulation method when creating a potential distribution using the above-mentioned method. InFIG. 10, a shape of a potential distribution is illustrated which created to correspond to an arrangement example of sample points61, sample points63, charge points67aand67b(also collectively referred to as charge points67), and charging points69aand69b(also collectively referred to as charge points69) in a vertical cross-section passing through the mobile object position55when a wall54is present around a mobile object position55.

As illustrated inFIG. 10, for example, a virtual potential141is a virtual potential curve generated from the charge point67a. A virtual potential143is a virtual potential curve generated from the charge point67b. A virtual potential144is a virtual potential curve generated from the charge point69a, and a virtual potential145is a virtual potential curve generated from the charge point69b. The coefficients Qi calculated using Equation 2 are considered in the virtual potentials141to145.

By adding all the virtual potential curves generated from all the charge points67and69including points not shown and satisfying the conditions at the sample points61and63, a potential distribution147is obtained. That is, in the potential distribution147based on the conditions of the sample points61and63, the potential at a wall boundary132and a wall boundary137is set to 0, and the potential at a virtual boundary133and a virtual boundary135is set to 1.

FIG. 11illustrates generation of potentials. As illustrated inFIG. 11, when a wall151and a wall152are present in a map150, the neighborhood creating device3extracts the outlines of the wall151and the wall152and performs a closing process thereon as illustrated with reference toFIGS. 5 and 6. Accordingly, as illustrated in wall data153, plural sample points156and plural charge points157are arranged. The neighborhood creating device3creates a virtual boundary in the neighborhood area of the portable terminal5, creates potentials, and outputs the result through the use of the output unit30. The result is information on coordinates of contour lines for displaying contour lines, for example, like potential contour lines159of the display example158. At this time, the potential contour lines159spread to avoid the wall151and the wall152.

A calculation error will be described below with reference toFIGS. 12 and 13. A disadvantage of the charge simulation method is that it does not have effective method for suppressing a calculation error. It has been tried to analytically calculate the optimal arrangement of the charge points for reducing the error, but it is basically difficult to suppress an increase in error when the shapes of the boundaries become complicated. The charge simulation method can solve a potential problem at an ultrahigh speed, but it is considered the number of engineering application examples is small due to the error. However, in the application of neighborhood creation in this embodiment, the influence of the error of the charge simulation method can be relatively reduced.

FIG. 12illustrates a distribution of potentials on a plane calculated using the charge simulation method.FIG. 13illustrates the relationship between the potential value and the threshold value.FIG. 12illustrates an example where a mobile object position55is present in a space surrounded with a wall84. The potential calculation result is marked by potential contour lines73to83.

For example, the potential of the potential contour line73is 0.3. The potential of the potential contour line75is 0.2, the potential of the potential contour line77is 0.1, and the potential of the potential contour line79is 0.05. The potential of the potential contour line81is 0.01, the potential of the potential contour line82is 0.005, and the potential of the potential contour line83is 0.001.

It is known that the error of the charge simulation method is the maximum on the boundary (the maximum principle of error). InFIG. 12, it can be seen that the shape of the potential distribution is clearly deformed in the vicinity of the wall84as a boundary but a smooth distribution is maintained in the vicinity of the center having a high potential. That is, for example, the potential contour lines73to79have a relatively small error. However, the potential contour lines81to83have a deformed shape which is present on the outside85of the wall84and have an error larger than that in the vicinity of the center. In this way, the error increases with the base of the potential.

In this embodiment, the neighborhood creating system1calculates the “neighborhood area” of a mobile object. For example, when the use of closeness determination of determining whether plural mobile objects get close is assumed, setting of the range of the neighborhood area to be wide away from the center of the potential is not typically used. That is, in this embodiment, since only information of a part (the vicinity of the center having a large altitude) having a small potential error generated using the charge simulation method can be used, it is possible to suppress the influence of the error which is the demerit of the charge simulation method.

As illustrated inFIG. 13, a threshold value88is provided to a potential distribution87and a part of which the potential is higher than the threshold value88is used as a usable range89. Accordingly, only the potential having a small error is used, thereby suppressing the influence of the error.

In order to reduce the calculation load, it is considered that a maximum range for determining the range of the sample points and the charge points used to calculate the potential is set.FIG. 14illustrates an example of the maximum range. As illustrated inFIG. 14, in a range setting example90, a maximum range91is set as the maximum range in the neighborhood area of a person11, and a virtual wall is arranged around a mobile object based on the maximum range91. The virtual boundary based on the maximum range91is a boundary having a potential of 0 similarly to the surrounding wall, unlike the virtual boundary59around the mobile object position55. By setting this maximum range91, the spreading of the potential distribution is in the set maximum range. Here, the maximum range91has a circle shape centered on the position of the mobile object position55.

To correspond to the maximum range91, plural sample points91aare arranged on the boundary of the maximum range91and the corresponding charge points91bare arranged outside the maximum range91as described above. When the maximum range such as the maximum range91is set, a potential distribution which spreads from the mobile object position55, for example, to the overall map area of the range setting example90is not generated. However, by narrowing the ranges of the sample points and the charge points to be calculated so as to be within the maximum range, the calculation load may be reduced.

FIG. 15illustrates a structural example of position information162. As illustrated inFIG. 15, the position information162is information representing positions of mobile objects and includes a time stamp164, a mobile object ID165, and a mobile object position166. The position information162is acquired from the position estimating device7by the position acquiring unit21.

The time stamp164represents a time at which the position information162is acquired. The mobile object ID165is identification information of each mobile object. The mobile object position166is coordinates at the time of the time stamp164and includes an X coordinate and a y coordinate. For example, the position information162represents that a mobile object with a mobile object ID of 001 is located at a position of x=12.380 and y=45.173 at 17:14:32 of Apr. 27, 2012. The position information162is acquired every predetermined time and is stored in a storage unit not shown in the neighborhood creating device3.

FIG. 16illustrates a structural example of sample point data168. The sample point data168includes an ID170, an X coordinate171, and a Y coordinate172. The ID170is identification information of a sample point. The X coordinate171and the Y coordinate172are coordinates of a sample point. The sample point data168represents that, for example, a sample point with an ID of 001 is a point located at a position of x=24 and y=18. As described above, the sample points are arranged on the outline extracted based on the map stored in the map storage unit27, on the virtual boundary59, or on the boundary of the maximum range91. The charge points are configured as the charge point data having the same configuration. The sample point data168and the charge point data are input to the solution calculating unit41.

FIG. 17illustrates a structural example of the output data of the neighborhood creating device3. Neighborhood data175is the output data of the neighborhood creating device3and includes a mobile object ID176, an X coordinate177, a Y coordinate178, and a potential179. The neighborhood data175represents that, for example, the potential of the mobile object with an ID176of 101 is calculated to be 0.05 at a point of X=10 and Y=15.

FIG. 18illustrates a display example of a neighborhood area using the potentials calculated as described above. As illustrated inFIG. 18, a display example180expresses the neighborhood areas created for the mobile object positions55-1to55-6by the use of potential contour lines. It can be seen that the neighborhood areas corresponding to the mobile object positions55-1to55-6spread to avoid untraversable walls.

FIG. 19illustrates a temporal variation of a neighborhood area of a mobile object position55.FIG. 19illustrates states where the neighborhood area of the mobile object position55moves as expressed by the contour lines57-1to57-12in display examples183to194. In the display examples183to194, the neighborhood area of the mobile object position55spreads and moves to avoid the walls151and152.

The operating method of the neighborhood creating system1having the above-mentioned configuration will be described with reference toFIG. 20.FIG. 20illustrates the operating method of the neighborhood creating device3. As illustrated inFIG. 20, the position acquiring unit21of the neighborhood creating device3acquires the position information162at a certain time. The wall data acquiring unit39acquires the sample point data168and the charge point data having the same configuration as the sample point data168from the wall data storage unit37(S201).

The mobile object data arranging unit31sets a virtual boundary59of the mobile object position55based on the acquired position information162as described with reference toFIG. 7Cand arranges the sample points63and the charge points69to the virtual boundary59based on the acquired position information as illustrated inFIG. 8(S202).

The range arranging unit35determines the maximum range91as illustrated inFIG. 14and arranges the sample points and the charge points based on the maximum range91(S203). The wall data acquiring unit39arranges the wall data based on the map storage unit27by acquiring, for example, the sample point data168and the corresponding charge point data which are created by the wall data creating unit25and stored in the wall data storage unit37(S204).

The solution calculating unit41determines the superposition coefficients Qi by solving the simultaneous equation 2 (S205). The potential generating unit43superposes all the potentials reflecting the coefficients Qi determined in S205to create a potential distribution (S206).

FIG. 21illustrates the operating method of a portable terminal5. As illustrated inFIG. 21, the portable terminal5receives communications from at least three APs9and transmits the identification information of the APs9and the information on the time consumed in the communications to the position estimating device7(S207). When the neighborhood creation in the neighborhood creating device3described with reference toFIG. 20is ended, the portable terminal5acquires the created neighborhood information (S208). The portable terminal5displays the acquired information on the display unit5a, for example, as illustrated in the display example180ofFIG. 18or the display examples183to194ofFIG. 19.

As described above, in the neighborhood creating system1according to the first embodiment, the portable terminal5communicates with at least three APs9and transmits the result to the position estimating device7, and thus the position estimating device7specifies the position of the portable terminal5. The neighborhood creating device3acquires the position data of the portable terminal5from the position estimating device7. In the neighborhood creating device3, the mobile object data arranging unit31arranges, for example, the mobile object data130based on the acquired position data, and the range arranging unit35determines the maximum range of the neighborhood area based on the calculation result of the velocity calculating unit33. On the other hand, the wall data acquiring unit39acquires, for example, the wall data97based on the map and arranges the sample points and the charge points. The solution calculating unit41creates the simultaneous equation 2 based on the arranged mobile object data130and the arranged wall data97, and calculates the coefficients Qi as the solutions of the equations. The potential generating unit43creates the distribution of potentials with the mobile object based on the solutions of the solution calculating unit41.

As described above, in the neighborhood creating system1according to the first embodiment, the walls and the like through which a mobile object is not able to move are extracted and the outlines thereof are extracted, for example, using a map which has been converted into binary image data of walls and passages. A closing process is performed on the walls to extract outlines, the sample points are arranged along the outlines of the walls, and the charge points are arranged along the outlines subjected to the closing process. Accordingly, the wall data including information of the sample points and the charge points based on the map may be automatically arranged.

On the other hand, by acquiring the mobile object position55of the portable terminal5specified by the portable terminal5and the position estimating device7, the mobile object data including the sample points and the charge points based on the mobile object position55may be automatically arranged.

At this time, it is possible to create the neighborhood using high-accuracy position detection, in which a position is acquired, for example, using the wireless LAN-APs, as the indoor positioning method of acquiring position information in a place which GPS signals do not reach, such as stations or commercial facilities.

According to the neighborhood creating system1, it is possible to create a neighborhood area in consideration of walls through which a person11is not able to move and to create neighborhood suitable for the circumstances such as moving paths. That is, a potential distribution spreading along indoor traversable areas may be created, for example, by arranging the charge points and the sample points along the wall surfaces on an indoor map. By employing the charge simulation method which is a numerical solution method of a partial differential equation as a method of calculating a potential at a high speed, it is possible to perform processes at a speed at which the neighborhood creating process can be performed in real time.

The solution of the Laplace equation used to create the neighborhood has the following features and merits. That is, the solution of the Laplace equation is continuously smooth and does not have an extremal value other than a maximum point. Therefore, it is possible to naturally express a shape which spreads from a mobile object to avoid walls by creating a potential distribution in which the presence position of a person (mobile object) is the maximum and the wall surface is the minimum. Since the solution of the Laplace equation is a function of a position, a quantity (an altitude of potential) is present at a point on a map. This is a quantity decreasing with an increase in distance from the position of the mobile object (the center of the potential) and is thus suitable for creating the neighborhood of a mobile object.

According to the neighborhood creating system1, it is possible to create a neighborhood area, which is defined for each mobile object, which has a continuous distribution, and which varies depending on the behavior of a mobile object or the surrounding spatial structure, at a high speed using high-accuracy positions and a high-accuracy map. Therefore, a detailed neighborhood creating service without erroneous determination may be realized in an indoor place.

At this time, a potential distribution in which the presence position of a mobile object is the maximum point and which spreads along traversable areas such as passages to avoid obstacles (walls) may be used as the neighborhood area of a mobile object. That is, sample points arranged along the walls and sample points arranged to surround the center of the mobile object are set using the calculation of the charge simulation method, and the conditions are designated such that the value at the sample points around the mobile object is the maximum and the value at the sample points of the walls is the minimum. Accordingly, it is possible to calculate a potential distribution which spreads from the position of the mobile object to avoid the walls at a high speed. By restricting the range of a neighborhood area, it may be made to be difficult to receive the influence of an error specific to the charge simulation method.

By arranging the sample points91aand the charge points91b, for example, on a circle centered on a mobile object and setting a virtual wall, only the sample points and the charge points within the range of the range setting example90are subjected to the calculation, thereby enhancing the processing speed. The maximum range of the neighborhood area may be designated arbitrarily.

In this way, it is possible to create a “neighborhood area” of a mobile object, which is used to realize an indoor position information service, at a high speed. According to the neighborhood creating system1, since places which a person is able to pass through or to be present in are restricted due to an indoor building structure, it is possible to provide a method of defining a neighborhood area in consideration of the structure.

Modification Example

Hereinafter, a modification example will be described. The configuration of a neighborhood creating system according to this modification example is the same as the configuration of the neighborhood creating system1according to the first embodiment. Therefore, the same elements are referenced by the same reference numerals and the description thereof will not be repeated.

In the modification example, the velocity calculating unit33illustrated inFIG. 2calculates the moving speed and the moving direction of a portable terminal5based on the position information of the portable terminal5and the corresponding time information acquired by the position acquiring unit21and, for example, the difference between the previous position and the present position.

In this modification example, the range arranging unit35deforms the maximum range based on the moving speed and the moving direction calculated by the velocity calculating unit33when arranging the calculation range for crating the neighborhood area of the portable terminal5. The deforming method will be described later. The solution calculating unit41creates simultaneous equations based on the mobile object data, the maximum range based on the velocity, and the wall data and calculates the solutions thereof, thereby calculating the solutions based on the deformed maximum range.

FIG. 22illustrates a modification of the range setting example90illustrated inFIG. 14. As illustrated inFIG. 22, in this modification example, the maximum range213is deformed depending on the velocity214as illustrated in a range setting example212. At this time, the velocity calculating unit33calculates the velocity214and the traveling direction of the person11(the portable terminal5) based on the position information162. The range arranging unit35changes, for example, the ratio of the major axis and the minor axis of the maximum range213based on the calculated velocity vector214to set the range to an ellipse of which the major axis is matched with the traveling direction of the portable terminal5. It may be also considered that the center, the major axis, and the minor axis of the ellipse are changed depending on the velocity and the traveling direction of the mobile object. The other configurations and operations are the same as those of the neighborhood creating system1according to the first embodiment and thus description thereof will not be repeated.

As in this modification example, the shape of the maximum range213is set to an ellipse, not to a simple circle, and is deformed depending on the velocity214and the traveling direction. Accordingly, the neighborhood area reflects the behavior of the mobile object as well as the spatial structure, and it is thus possible to determine the closeness including prediction.

Hereinafter, a neighbor creating system according to a second embodiment will be described with reference toFIGS. 23 to 30. In this embodiment, the same elements and operations as in the first embodiment and the modification example will be referenced by the same reference numerals and detailed description thereof will not be repeated.

FIG. 23illustrates the functional configuration of a neighborhood creating device3-2according to the second embodiment. As illustrated inFIG. 23, the neighborhood creating device3-2includes a position acquiring unit21, a neighborhood creating unit23, a wall data creating unit25, a map storage unit27, a closeness determining unit29, and an output unit30.

The neighborhood creating device3-2according to this embodiment includes the closeness determining unit29in addition to the neighborhood creating device3according to the first embodiment and the modification example. The neighborhood creating unit23creates a neighborhood area for each of plural mobile objects, and the closeness determining unit29determines whether the plural mobile objects are present in the predetermined neighborhood areas based on a potential distribution representing the neighborhood area created for each mobile object. The output unit30outputs the determination result of the closeness determining unit29.

FIG. 24illustrates the closeness determination. As illustrated inFIG. 24, potential distributions215,216,218, and219are created for the mobile objects at positions a1 to a4 in a vertical cross-section of a space in which the mobile objects are present. A threshold value P0 is set as a threshold value for the closeness determination. This threshold value is a reference value used to determine that the mobile objects are close to each other when the potential at an intersection of the potential distributions created for the different mobile objects is higher than the threshold value.

In the example shown inFIG. 24, parts of which the potential is higher than the threshold value P0 are extracted from the potential distributions215,216,218, and219. Accordingly, the potential distribution217and the potential distribution220marked by a bold line are extracted. At this time, since the mobile objects corresponding to the potential distributions215and216belong to the same group of potential distribution217, it is determined that both are close to each other. Similarly, since the mobile objects corresponding to the potential distributions218and219belong to the same group of potential distribution220, it is determined that both are close to each other. Actually, the portions of which the potential is higher than the threshold value are extracted from the potential distributions of the neighborhood areas of all the mobile objects and the closeness determination is performed.

FIG. 25illustrates a result of the closeness determination. When the presence of a wall221is not considered as in a closeness determination example227ofFIG. 25, a route225representing the shortest distance between the mobile object223and the mobile object224intersects the wall221at an intersection226and is a route which is actually untraversable. In a closeness determination example229, since the neighborhood area is created to avoid the wall221, a route228is a route reflecting the wall221and the closeness determination is performed based on the route228.

FIG. 26illustrates the closeness determination when mobile objects231to233are present in a space inside walls230. It is assumed that the time passes in the order of a display example240, a display example241, a display example242, and a display example243. As illustrated inFIG. 26, in the walls230, the mobile objects231to233are present in places partitioned by the walls230. In the display examples241to243, the mobile object233slowly gets close to the mobile object231. In the display example243, the mobile object231and the mobile object233are determined to be close to each other. However, since the mobile object231and the mobile object232interpose the wall230therebetween, the potential distributions thereof do not overlap with each other and both are not determined to belong to the same group. As a result, both mobile objects231and232are not determined to be close to each other.

FIG. 27illustrates a display example for determining the closeness of plural mobile objects. This display example245is prepared by assuming dummy tracks of plural mobile objects freely moving on a target map and causing the neighborhood creating device3to perform the closeness determination of the mobile objects moving along the dummy tracks. In the example illustrated inFIG. 27, a group247of two mobile objects determined to be close to each other and a group248of three mobile objects are distinctly displayed in addition to neighborhood areas246of single mobile objects.

FIG. 28illustrates a variation in process time when the number of mobile objects varies in the closeness determination of the second embodiment.FIG. 29illustrates the process time due to the variation in the number of mobile objects predicted from the relationship illustrated inFIG. 28. The number of mobile objects represents the number of mobile objects of which the neighborhood area will be created by the neighborhood creating unit23for the purpose of the closeness determination of the closeness determining unit29. The process time represents the time until the display of a result is completed after the portable terminal5as one mobile object transmits information for specifying a position to the position estimating device7.

InFIG. 28, the horizontal axis represents the number of mobile objects and the vertical axis represents the process time. Through conversion from the scale of the map used for the calculation, the length of each pixel is 1.24 m. The number of charge points is 534 and the operating frequency of the neighborhood creating device3used for the calculation is 2.8 GHz.

InFIG. 28, the ranges of the measured process times when the number of mobile objects are 1 to 10 are illustrated as measured values249-1to249-10. It is thought that the relationship between the number of mobile objects and the process time is expressed as a straight line249based on the measured values249-1to249-10. That is, it is thought that the process time linearly increases with the increase in the number of mobile objects. In the example illustrated inFIG. 28, the closeness determining process can be performed in the process time of about 44 msec for each mobile object.

When the process time depending on the number of mobile objects is predicted using the straight line249, as illustrated inFIG. 29, the process time with the number of mobile objects of 20 is 922 ms and the process time with the number of mobile objects of 30 is 1356 ms. Similarly, the process time with the number of mobile objects of 100 is 4391 ms.

FIG. 30illustrates a method of the closeness determining process in the second embodiment. As illustrated inFIG. 30, the neighborhood creating device3-2waits until the position acquiring unit21updates the position (S251). When the position is not updated (No in S252), the waiting state is maintained.

When the position is updated (YES in S252), the neighborhood creating device3-2creates the neighborhood area of a mobile object through the use of the same process as described in the first embodiment and the modification example (S253). The closeness determining unit29superposes the potential distributions of the created neighborhood areas of the mobile objects and creates a single distribution including the potential distributions215to219, for example, as illustrated inFIG. 24(S254). The closeness determining unit29extracts the areas of which the potential is higher than the threshold value in the created distribution (S255). That is, in the example illustrated inFIG. 24, the potential distribution217and the potential distribution220of which the potential is higher than the threshold value P0.

The closeness determining unit29distinguishes a continuous area from the areas, of which the potential is higher than the threshold value and which have been extracted in S255, through the use of a labeling process (S256). That is, in the example illustrated inFIG. 24, the potential distribution217and the potential distribution220are distinguished as different areas. The closeness determining unit29determines that the mobile objects present in the same area are close (S257). That is, in the example shown inFIG. 24, it is determined that the moving position present at the positional and the mobile object present at the position a2 are close to each other. In addition, it is determined that the moving position present at the position a3 and the mobile object present at the position a4 are close to each other. The neighborhood creating device3performs the process of S251again, for example, when an end of process is not instructed from the portable terminal5(NO in S258), and ends the process flow when an end of process is instructed (YES in S258).

As described above, in the neighborhood creating system according to the second embodiment, the closeness determination is performed in an indoor space in which the traveling of a person (mobile object) is restricted by using the neighborhood area in consideration of the spatial structure. At this time, it is possible to detect the closeness of persons (mobile objects) based on the distance of an actual movement route instead of the linear distance. The actual movement route is a route along which a mobile object is predicted to actually move. The closeness determination based on the actual movement route may be performed by creating the potential distribution spreading to avoid walls and the like through which a mobile object is not able to move.

In the closeness determination according to the second embodiment, the potential distributions created for the plural mobile objects are superposed as described above, the portions of which the potential is higher than the threshold value are extracted therefrom, and continuous areas are distinguished through a labeling process. Therefore, it is possible to perform the closeness determination in consideration of the spatial structure around a mobile object without giving a feeling of wrongness at a high speed. At this time, when a mobile object is defined as a person carrying a portable terminal5, persons present across a wall may not be determined to be close but only persons present in the same place not partitioned by the wall may be determined to be close. In addition to the simple closeness determination, the closeness in consideration of a route between mobile objects such as the route228can be also calculated numerically.

According to the second embodiment, the process of performing the closeness determination on all combinations of mobile objects is not used, and the process time only increases linearly even with an increase in the number of mobile objects. Therefore, with the increase in the number of mobile objects, the process time may be shorter than that in the case where the closeness determination is performed on the combinations.

Hereinafter, a neighborhood creating system according to a third embodiment will be described with reference toFIGS. 31 and 32. In this embodiment, the same elements and operations as in the first embodiment, the modification example, or the second embodiment will be referenced by the same reference numerals and detailed description thereof will not be repeated.

FIG. 31illustrates the functional configuration of a neighborhood creating device3-3according to a third embodiment. As illustrated inFIG. 31, the neighborhood creating device3-3includes a position acquiring unit21, a neighborhood creating unit23, a wall data creating unit25, a map storage unit27, a position correcting unit259, and an output unit30.

The neighborhood creating device3-3according to this embodiment includes the position correcting unit259in addition to the neighborhood creating device3according to the first embodiment and the modification example. The position correcting unit259corrects a mobile object position166based on the neighborhood area created by the neighborhood creating unit23, the mobile object position166of the portable terminal5acquired by the position acquiring unit21, and the wall data. When the mobile object position166is corrected, the position correcting unit259feeds back the corrected mobile object position166to the mobile object data arranging unit31. The output unit30outputs the correction result of the position correcting unit259.

FIG. 32illustrates the position correction in the third embodiment. As illustrated by an actual track260ofFIG. 32, a case where a mobile object262moves along a locus266extending from a mobile object position262ato a mobile object position262balong a wall264will be described. At this time, it is assumed that the neighborhood creating system1detects that the mobile object262moves along the calculated loci272,274, and276from a mobile object position262cto a mobile object position262eas the creation result270. Then, neighborhood areas282,284,286are created with the movement of the mobile object262.

Here, the neighborhood area286is created only on the left side of the wall264inFIG. 32. However, the calculated locus276based on the measurement of the position acquiring unit21goes over the wall264. In this case, since the mobile object position262fis not present inside the calculated neighborhood area286, it is determined that the calculated locus276is erroneous and the mobile object position166is corrected such that the position of the mobile object262is located on the left side of the wall264.

As described above, in the neighborhood creating system according to the third embodiment, there is a possibility of use as a filter for correcting a positioning error. For example, when it is detected that a mobile object enters a fixed area such as a room and the mobile object is located just before the outside of the wall of the room, a small positioning error serves as a cause of erroneous determination. In order to solve this problem, a process of determining the updated measured position to be an incorrect value and correcting the measured position to be within the neighborhood area when the present position is included in the neighborhood area using the neighborhood area calculated at the previous position can be considered. Since the neighborhood area goes over the wall, it is possible to suppress the erroneous determination on entering the room.

When the neighborhood area is analyzed as a latent movable range of a mobile object, it can be used as a position correcting filter when a measured coordinate intermits in a neighborhood area. That is, the intermitted measured position may be set to be inside the neighborhood area created prior to one step by the neighborhood creating system1.

Hereinafter, a neighborhood creating system1-2according to a fourth embodiment will be described with reference toFIG. 33. In this embodiment, the same elements and operations as described in the first embodiment, the modification example, the second embodiment, or the third embodiment will be referenced by the same reference numerals and detailed description thereof will not be repeated.

FIG. 33illustrates the structure of the neighborhood creating system1-2according to the fourth embodiment. As illustrated inFIG. 33, the neighborhood creating system1-2includes a neighborhood creating device3, one or more portable terminals6-1, . . . ,6-n, and an initial position specifying device8. The portable terminals6-1, . . . ,6-nmay be also collectively or representatively referred to as a portable terminal6.

The portable terminals6are terminal devices such as portable information terminals or mobile phones which are carried, for example, by persons11-1,11-2, . . . and move therewith. In this embodiment, the portable terminal6is an example of the mobile object. The portable terminal6includes a display unit6ahaving an input unit such as a touch panel, an initial position setting device, a wireless receiver that receives information from the neighborhood creating device3and the initial position setting device8, a motion detecting sensor such as a gyro sensor or an acceleration sensor detecting the motion of the portable terminal6, a control unit that controls the operation, and a storage unit. The portable terminal6enables to input information and enables to display information such as a map or a created neighborhood area.

The portable terminal6acquires its own initial position by communicating with the initial position setting device8through a wireless communication network. The portable terminal6transmits the set initial position and the information detected by the motion detecting sensor to a position estimating device7through a wireless network15. The position estimating device7estimates the position of the portable terminal6based on the received information. The portable terminal6receives created neighborhood information from the neighborhood creating device3through a wireless network and presents the received neighborhood information. In this embodiment, the processes other than the self position detecting method may employ the same as described in the first embodiment, the modification example, the second embodiment, or the third embodiment.

As described above, in the neighborhood creating system1-2according to the fourth embodiment, it is possible to use a high-accuracy positioning technique into which an autonomous navigation using a gyro sensor or an acceleration sensor mounted on the portable terminal6is combined after acquiring the initial position and, for example, positioning accuracy of 1 m or less is expected. According to the neighborhood creating system1-2, a position of a person can be practically measured with higher accuracy. Accordingly, since a motive for preparing maps including indoor room arrangement information in addition to outdoor information can be provided, it is possible to provide a finer service interlocking with situations of persons to a user.

Wall data97and wall data153are examples of the obstacle data, and the wall data acquiring unit39is an example of the obstacle data acquiring function. The mobile object data arranging unit31is an example of the mobile object data creating function and the range arranging unit35is an example of the range setting function.

The disclosure is not limited to the above-mentioned embodiments, but may have various configurations of embodiments without departing from the concept of the disclosure. For example, the first to fourth embodiments and the modification example may be combined within an allowable range. For example, in the first embodiment, the maximum range of S203may be defined as an area having a shape other than a circle or an ellipse, such as an area based on the shape of the surrounding walls.

When the portable terminal5or the portable terminal6is provided with a self position estimating function, the self position may be notified directly to the neighborhood creating device3without using the position estimating device7. By combining the autonomous navigation using gyro sensor or an acceleration sensor mounted on the portable terminal with the wireless LAN positioning, it is possible to enable higher-accuracy positioning. The notification of the process result from the neighborhood creating device3to the portable terminal5may be carried out using an electronic mail. The neighborhood creating system according to the first to fourth embodiments or the modification example may be applied to applications other than the closeness determination or the position correction. For example, the neighborhood creating system can be widely applied to applications such as reproduction of a sound field in virtual reality and a trigger area for providing services based on a position as an example using the route distance between points.

In the reproduction of a sound field in virtual reality, when a sound emitted from a sound source in an actual space is virtually reproduced, it can be thought that it is possible to reproduce the sound with a more realistic sensation by changing the sound volume transmitted from the sound source to a listener depending on the route distance between the sound source and the listener. At this time, it is preferable that the sound volume be changed to follow a slight variation in position of the listener. In consideration of this purpose, since it is desired to calculate the route distance from the sound source in continuous positions on a map instead of discrete spots, it is possible to use the neighborhood creating system according to the first to fourth embodiments and the modification example.

As another example, a global route of a robot may be efficiently planned using a potential. By calculating the optimal route in a state space through generalization, for example, it may be possible to create a track of a manipulator. In the neighborhood creating system according to the first to fourth embodiments and the modification example, it is possible to create a route or a track at a high speed.

The arrangement of the charge points and the sample points has a large influence on calculation accuracy. In general, a wide arrangement interval tends to cause a large calculation error. When the number of points is excessively large, the calculation load increases. A decrease in the number of points may be considered by densely arranging points in a narrow place (a place in which walls are densely present) and coarsely arranging points in a wide place.An example of a computer which is used in common to cause the computer to perform the operations of the neighborhood creating method according to the first to fourth embodiments and the modification example will be described below.FIG. 34illustrates an example of a hardware configuration of a standard computer. In the computer300illustrated inFIG. 34, a central processing unit (CPU)302, a memory304, an input unit306, an output unit308, an external storage unit312, a medium driving unit314, and a network access unit are connected via a bus310. The CPU may use one or more processors. Another embodiment may use one or more CPUs instead of the CPU.

The CPU302is an arithmetic processing unit that controls the entire operation of the computer300. The memory304is a storage unit that stores a program controlling the operation of the computer300in advance or that is used as a work area as occasion calls when executing the program. The memory304may include, for example, a random access memory (RAM) and a read only memory (ROM).

The input unit306is a unit that acquires input of a variety of information from a user, which is correlated with the manipulation details thereof and that transmits the acquired input information to the CPU302, when it is manipulated by the user of the computer and includes, for example, a keyboard and a mouse. The output unit308is a unit that outputs the process results of the computer300and includes a display device. For example, the display device displays a text or an image based on display data transmitted from the CPU302.

The external storage unit312is a storage unit such as a hard disk and is a unit that stores various control programs which are executed by the CPU302, acquired data, or the like. The medium driving unit314is a unit that writes and reads data to and from a portable recording medium316. The CPU302may perform various control processes by reading a predetermined control program recorded on the portable recording medium316through the use of the medium driving unit314and executing the read control program. The portable recording medium316is, for example, a compact disc (CD)-ROM, a digital versatile disc (DVD), or a universal serial bus (USB) memory. The network access unit318is an interface unit that manages transmission of various data to and from the outside in a wired or wireless manner. The bus310is a communication path that connects the units to each other and that enables data exchange therebetween.

The program causing a computer to perform the neighborhood creating method according to the first to fourth embodiments and the modification example is stored, for example, in the external storage unit312. The CPU302reads the program from the external storage unit312and causes the computer300to perform the neighborhood creating process. At this time, a control program for causing the CPU302to perform the neighborhood creating process is first prepared and stored in the external storage unit312. A predetermined instruction is input to the CPU302through the input unit306and this control program is read and executed from the external storage unit312. This control program may be stored in the portable recording medium316.

A position acquiring unit21, a wall data creating unit25, mobile object data arranging unit31, velocity calculating unit33, range arranging unit35, a wall data acquiring unit39, solution calculating unit41, potential generating unit43, closeness determining unit29, and a position correcting unit259may be configured to be programs. These programs may be executed by one or more processors.

In the first to fourth embodiments and the modification examples, the position acquiring unit21, the wall data creating unit25, the closeness determining unit29, the mobile object data arranging unit31, the mobile object velocity calculating unit33, the range arranging unit35, the wall data acquiring unit39, the solution calculating unit41, the potential generating unit43, the position correcting unit259, and the output unit30may employ a structure using at least one hardware configuration of (1) to (4) described below. The units may be shared through a multi-tasking process of the CPU. One or more of the position acquiring unit21, the wall data creating unit25, the closeness determining unit29, the mobile object data arranging unit31, the mobile object velocity calculating unit33, the range arranging unit35, the wall data acquiring unit39, the solution calculating unit41, the potential generating unit43, the position correcting unit259, and the output unit30may be constructed, for example, using a CPU and a memory.

(1) A configuration in which one or more CPUs perform a predetermined process by loading a program onto a memory304from an external storage unit312, a variable recording medium316, or the like and executing the loaded program;

(2) A configuration including a field programmable gate array (FPGA);

(3) A configuration including an application specific integrated circuit (ASIC); and

(4) A configuration including a circuit.

Additional Notes for the Embodiments

Note 1. A neighborhood creating device, comprising: one or more processors configured to acquire position information representing a position of a mobile object, create mobile object data representing a condition associated with a movable range of the mobile object based on the position information, acquire obstacle data representing a condition associated with a place through which the mobile object is not able to move, and create neighborhood information satisfying both conditions represented by the mobile object data and the obstacle data and continuously representing a movable range of the mobile object around the mobile object; and a memory coupled to the one or more processors.

Note 2. The neighborhood creating device according to claim1, wherein the obstacle data includes a condition associated with a place through which the mobile object is not able to move.

Note 3. The neighborhood creating device according to claim2, wherein the one or more processor is further configured to create simultaneous equations based on the mobile object data and the obstacle data and that calculates solutions of the simultaneous equations, and to solve the simultaneous equations through the use of a charge simulation method using Laplace equations as the simultaneous equations.

Note 4. The neighborhood creating device according to claim3, wherein the one or more processor is further configured to create a sample point used to set a potential associated with the movable range of the mobile object and a point as a charge point at which the potential is generated as the mobile object data, wherein the one or more processor is further configured to acquire a sample point used to set a potential associated with a place through which the mobile object is not able to move and a charge point at which the potential is generated as the obstacle data, wherein the one or more processor is further configured to set a condition such that the potential of the sample point in the mobile object data is higher than the potential of the sample point in the obstacle data and to calculate coefficients to be multiplied by the potentials as the solutions of the simultaneous equations such that the potentials of the sample points satisfy the condition when the potentials generated at the charge points are superposed, and wherein the one or more processor is further configured to calculate the potentials as the neighborhood information based on the solutions.

Note 5. The neighborhood creating device according to claim3, the one or more processor is further configured to determine a maximum range in which the neighborhood information is calculated based on the position information and to set range data representing a sample point used to set a potential associated with the maximum range and a point as a charge point at which the potential is generated, wherein the one or more processor is further configured to set a condition such that the potential of the sample point in the mobile object data is higher than the potentials of the sample point in the range data and the sample point in the obstacle data, and to solve the simultaneous equations through the use of a charge simulation method.

Note 6. The neighborhood creating device according to claim5, the one or more processor is further configured to calculate a speed and a moving direction of the mobile object based on the position information, wherein the one or more processor is further configured to set the maximum range based on the speed and the moving direction.

Note 7. The neighborhood creating device according to claim1, the one or more processor is further configured to determine whether a plurality of the mobile objects get close, wherein the one or more processor is further configured to acquire positions of the plurality of mobile objects, wherein the one or more processor is further configured to create a two-dimensional distribution of the neighborhood information by performing processes on the plurality of mobile objects, and wherein the one or more processor is further configured to determine whether the plurality of mobile objects get close based on the superposition of the two-dimensional distributions of the neighborhood information of the plurality of mobile objects.

Note 8. The neighborhood creating device according to claim7, wherein the one or more processor is further configured to set a threshold value of the neighborhood information, to create a two-dimensional distribution of the neighborhood information having a value equal to or more than the threshold value, and to determine whether the mobile objects in the continuous two-dimensional distributions of the neighborhood information get close.

Note 9. The neighborhood creating device according to claim1, the one or more processor is further configured to correct the position information of the mobile object by creating the neighborhood information at different times.