JP4587217B2 - Night driving assistance navigation device - Google Patents

Description

  The present invention relates to a navigation apparatus that guides a vehicle to a destination along a guidance route, and more particularly to a night travel assistance navigation device that can set a guidance route by selecting the brightest road when traveling at night.

  In a general navigation apparatus mounted on a vehicle or the like, a map / information data storage such as a CD-ROM, a DVD-ROM, a hard disk, etc., which stores map data for drawing a map and facility information data for retrieving a facility, etc. A vehicle, a data capture device that captures data from the map / information data storage medium, a monitor that displays a map, etc., and an autonomous navigation device that uses a GPS receiver, a mileage sensor, a gyroscope, etc. It has a vehicle position detection device that detects the position and the direction of travel, fetches map data including the current position of the vehicle from a map / information data storage medium, and monitors a map image around the vehicle position based on this map data The vehicle position mark is superimposed on the monitor screen, and the map image is scrolled as the vehicle moves. Le displayed, or moving the fixed vehicle position mark a map image on a screen, so that seen whether the vehicle is traveling where the current at a glance.

  Map data stored in a map / information data storage medium such as a CD-ROM, DVD-ROM, or hard disk is divided into longitude and latitude widths of appropriate sizes according to various scale levels. A road or the like is stored as a coordinate set of nodes expressed by longitude and latitude. A road consists of two or more nodes connected to each other. Map data displays a road layer consisting of a road list, a node table, an intersection configuration node list, etc., and roads, buildings, facilities, parks, rivers, etc. on the map screen. Map data such as a background layer to be used and information data for displaying characters, map symbols, etc., such as administrative division names such as city names, road names, intersection names, and facility names.

  In addition, this navigation device has a route guidance function for allowing a user to easily travel on a road toward a desired destination or waypoint (hereinafter referred to as “destination”) without making a mistake. Yes. According to this route guidance function, the user specifies and sets the items that the user wants to prioritize, such as the type of road to be used, travel distance, travel time, and fee, as conditions for determining the guide route. Can do. In general, when calculating the guidance route, the Dijkstra method, which is an algorithm for calculating the shortest distance and the shortest route between two points existing on the network, is used.

  In the case of a navigation device, as described above, in order to satisfy various requirements for the user's guidance route, the road distance is multiplied by a specific coefficient according to the calculation condition and road type. It is defined as the cost required to pass, and the route connecting the starting point and the destination with the minimum cost is calculated and used as the guidance route.

  For example, when calculating a guidance route giving priority to a toll road, a guide route that preferentially uses the highway is calculated by multiplying a coefficient so as to reduce the cost of the highway. Using the guide route calculation method described above, the route that matches the user's instructions is calculated by taking into account various conditions set by the user from the departure point to the destination. The route that best satisfies the conditions set by the user is calculated and used for guidance.

  In addition, the optimum guidance route calculated in accordance with the user's instruction or the route selected by the user from among a large number of candidates is stored as a guidance route, and the guidance route is defined as another route on the map image while traveling. When the vehicle approaches the intersection that should change its course, such as turning left or right on the guidance route, the intersection is enlarged and the intersection name is displayed , Guide the surrounding landmark facilities, draw an arrow indicating the direction to change the course and display it on the screen, or guide the turn left and right by voice Guidance is provided so that the user can pass through, and finally the user can be guided to the destination.

  On the other hand, in the field of information collection satellites, there are artificial satellites represented by the US Defense Meteorological Satellite Program (hereinafter referred to as “DMSP”) that can observe ground light at night. By receiving and processing information from such satellites in real time, services for investigating the operating conditions of fishing grounds distributed in the waters around Japan and for early detection of forest fires are expanding. The maximum resolution of DMSP currently in general use is about 1 km, but at present, preparations for launching a satellite capable of using data with higher resolution are in progress.

In the navigation device, the calculation time for searching for the optimum route is obtained by obtaining the shortest distance between two points on the displayed map based on a distance table between intersections recorded in addition to general map data. A technique for shortening is disclosed in Patent Document 1 below.
JP-A-6-317427

  Considering the state of night driving in a normal vehicle, the driver can recognize only a small part of the area illuminated by lighting such as a car headlight or street lamp. In particular, when the car light is a low beam, only objects up to about 30 m ahead can be identified. Therefore, when driving on a road where there is no lighting such as street lights at night, the driver finally notices its presence after the pedestrians and parked cars are illuminated by the headlights, In some cases, accidents cannot be avoided. As can be seen from the fact that nighttime fatal accidents account for 60% of all fatal accidents, this delayed recognition is a factor in serious accidents.

  Furthermore, when driving at night, the eyes of the driver are tired because the difference between the surroundings is so intense that the surroundings are dark and difficult to see, and the subject's eyes are staring at the other hand. As a result, it is very difficult to maintain concentration. For this reason, when driving at night, select the road with high visibility, that is, a bright road with sufficient lighting equipment such as streetlights as much as possible, and reduce the possibility of encountering or causing an accident as much as possible. It is important.

  When a user travels using the route guidance function of the navigation device as described above, the user is often unfamiliar with the area from the current position to the destination. The guidance route provided by the conventional navigation device is calculated so as to satisfy the conditions set by the user such as the type of road to be used, travel distance, travel time, and fee, so it is the same route regardless of day or night. The route obtained by the calculation may include a dark road with almost no lighting equipment such as a streetlight.

  When driving on an unfamiliar road with little lighting equipment at night, it is very difficult for a user to guess in advance where a pedestrian jumps out or where a car stops. The user feels the necessity of paying attention to the surroundings, and thus is considerably strained, and is likely to cause a reduction in attention due to fatigue. Further, when the calculated route passes through a mountainous area, it can be easily imagined that the tension of the user will be further increased due to factors such as a curve with poor visibility and the narrowness of the road.

  In addition, the user travels on the route according to the guidance of the navigation device, but even at the intersection of the guidance target that can be easily found during the daytime, the user is considered to be the guidance target due to its low visibility at night. It may be difficult to find the intersections and facilities that have become, and may be overlooked. Furthermore, there is a high possibility that the user will not pay enough attention to the surroundings because the user concentrates on finding the guidance target.

  As described above, the guidance route guidance in the conventional navigation device is intended only to arrive at the destination, so that considerations for ensuring the burden on the user during night driving and ensuring safety during driving are provided. There wasn't enough.

  Therefore, the present invention provides a user with a guidance route that preferentially uses a road that is as highly visible as possible when traveling at night, that is, there is a lighting device such as a streetlight in the surroundings and the surrounding situation is easy to check. An object of the present invention is to provide a night driving assistance navigation device that can improve the safety of driving at night and reduce the burden on the user.

  In addition to the functions of the conventional navigation device, the present invention detects that the surrounding area has become dark and determines whether or not the route should preferentially use a highly visible road. Means, a guidance route calculation means for calculating a route that preferentially uses a road with high visibility at night, a guidance control means for guiding the route calculated by the guidance route calculation means, and a conventional navigation device. In addition to the existing map database, it consists of a map database to which information on the brightness of the road at night is added.

  The map database used by the navigation device stores road links and nodes as information for performing guidance and route calculation. Usually, road links and nodes are grouped for each unit area (parcel or mesh). The node is point information, and is composed of position information and types of points such as high-speed junctions and general intersections.

  The road link is road information, and is composed of start / end position information, road length, and road attributes. In general, the start point and end point of a road link are expressed by nodes, and the attributes include the type and width of a road such as a highway and a general road. In addition, when the road link does not include road shape information, the storage destination of the shape link representing the road shape is added to the road link information. The navigation system calculates a guide route based on road information stored in these databases. In addition, in the example of FIG. 8, in addition to the information described above, information related to road brightness required in the present invention is added to the attribute of the road link.

  When calculating the guidance route using such data and guiding the route, when the user first sets the destination and the navigation device performs the guidance route calculation, or there is a guidance route already being guided When the guidance condition determining means determines that the visibility around the current position has decreased from the state of the illuminometer or headlight connected to the navigation device, the guidance condition determining means guides the guidance route using the bright road preferentially. It is determined that it is necessary to do so, and the guidance control means is notified. At this time, the guidance control means requests the guidance route calculation means to calculate a guidance route that preferentially passes a bright road.

  The guide route calculation means refers to the brightness information of the road included in the map database when calculating the guide route, and preferentially selects bright roads by multiplying only bright roads by a coefficient so as to reduce the passing cost. Calculate the guide route to use. The guidance control means performs guidance based on the route calculated by the guidance route calculation means.

  The guidance condition determination means notifies the guidance control means to perform normal guidance when it is determined that the visibility around the current position has become sufficiently high from the state of the illuminance meter or headlight connected to the navigation device. The guidance control means requests the guidance route calculation means to calculate a normal guidance route, and guides the guidance route calculated by the guidance route calculation means.

  In addition, the guidance control means determines a point where the guidance route is switched from a bright road to a dark road when there is a dark road during guidance of the guidance route, that is, a road with few street lamps and the surrounding visibility is very poor. In addition, the user is informed in advance that it is necessary to travel on a dark road, and the distance is guided. Further, after the calculation of the guide route, guidance may be provided regarding the distance and start point of a dark road included in the guide route.

A night driving assistance navigation apparatus according to the present invention has the above-described schematic configuration and performs the above-described operation. In particular, a map database that records road brightness data, and a road of the map database Night time guidance route calculation means for calculating a guidance route giving priority to a bright road using brightness data; and vehicle ambient brightness detection means for detecting brightness around the vehicle, wherein the vehicle ambient brightness detection means When it is detected that the surroundings are dark, the night corresponding guidance route calculation means calculates a guidance route giving priority to a bright road.

  Another night driving assistance navigation apparatus according to the present invention is the night driving assistance navigation apparatus, wherein the road brightness data calculated from the night satellite photograph is stored in a map database. It is characterized by being.

  Further, another night driving assistance navigation device according to the present invention is the night driving assistance navigation device in which the reference for defining the brightness of the road is changed in the urban area and other areas. It is characterized by data.

  Another night driving assistance navigation device according to the present invention is the night driving assistance navigation device, wherein road brightness information is stored in the map database as the road brightness data for each time zone, and the night driving assistance navigation device is provided. The corresponding guide route calculating means calculates the guide route by using the road brightness data and selecting a bright road according to the travel time.

  Another night driving assistance navigation device according to the present invention is characterized in that in the night driving assistance navigation device, the information of the night satellite photograph is stored in a map database and displayed superimposed on the map.

  Since the present invention is configured as described above, it is possible to provide a guidance route that preferentially passes on a bright road at night, thereby reducing the driving burden on the user and increasing the safety of driving at night. Can do. Further, since a route that preferentially passes through a bright road is guided, a guidance target for guidance performed by the navigation device can be easily found, so that the possibility of deviating from the guidance route is reduced.

  The purpose of the present invention is to reduce the user's driving burden when driving at night and to improve safety during driving at night, using the brightness data of the road, and calculating the guidance route that prioritizes the bright road This is realized by providing a navigation device including a guidance route calculation means.

  Embodiments of the present invention will be described with reference to the drawings. The night driving assistance navigation device of the present invention can be implemented in various modes. FIG. 1 shows main functional units of the night driving assistance navigation device implemented in a typical mode and their interrelationships. The functional block diagram showing is shown. The embodiment shown in FIG. 1 will be described below. In addition, the function part which performs each function in FIG. 1 can also be said to be a means which performs each function.

  In the example shown in FIG. 1, in a conventional navigation device, a data recording medium having road brightness data is used to calculate a night-time guidance route in which the surroundings are dark and visibility is reduced, The example which added the function part for enabling it to perform guidance is shown. The navigation apparatus shown in the figure includes a ROM that records software for comprehensively performing various predetermined functions in the system control unit 10, a CPU and a RAM for processing the software, etc. It is provided and is controlled comprehensively by associating each functional unit connected thereto.

  In the navigation apparatus of FIG. 1, a guidance route from the current location to the destination is calculated in the system control unit 10 and recorded so that the vehicle can be safely guided to the destination. A calculation guidance processing unit 11 is connected. The current route detected by the vehicle position detection unit 38 is input to the guidance route calculation guidance processing unit 11, and when the user inputs the destination to the instruction signal input unit 35 by various methods, the destination data is input. A current location / destination input unit 12 for input is provided.

  Also, when the user gives various instructions such as highway priority when calculating the guide route, this is input from the guide route calculation instruction input unit 13. In the present invention, the guide route for night time is calculated in particular. Therefore, when the user instructs the use of the function, the signal is also input, and the night corresponding guidance route guidance instruction detecting unit 14 detects the input of the signal. In the night-time guidance route guidance instruction detection unit 14, in addition to detecting the input of such a signal, a setting for performing guidance for the night-time guidance route when the visibility around the vehicle is poor is an initial setting. If set, the signal is also input.

  The guide route calculation guide processing unit 11 shown in FIG. 1 includes a normal guide route calculation unit 15 that performs various types of guide route calculations that have been performed in the past, and a night time that will be described in detail later. Although the night corresponding guidance route calculation unit 16 that performs the calculation of the corresponding guidance route is shown separately, this may be shown by incorporating the night corresponding guidance route calculation unit as one function in the normal guidance route calculation unit. it can. In the example of FIG. 1, the normal guidance route calculation unit 15 uses the data acquisition unit 32 for the guidance route between the current location input by the current location / destination input unit 12 to the destination, as in the conventional case. On the basis of the road data fetched via the route, the guide route is calculated according to the priority instruction from the guide route calculation instruction input unit 13, and after confirmation by the user is obtained, it is output to the guide route storage unit 25 and stored.

  The night corresponding guidance route calculation unit 16 of FIG. 1 includes a vehicle lighting detection unit 17 that detects that a vehicle equipped with this navigation device is lit, and an outside illuminance meter 18 that detects illuminance as brightness outside the vehicle. The vehicle lighting environment detection unit 19 captures these detection signals. As a result, when the user has instructed the calculation of the guidance route, when the headlight of the vehicle is turned on because the surroundings are dark, or when the above-mentioned external illuminance meter is attached to the vehicle, When the outside illuminance meter detects that the brightness outside the vehicle has become a predetermined value or less, that is, when it is detected that the vehicle has become darker than a predetermined value, the vehicle lighting environment detection unit 19 detects that the vehicle is in an environment where the vehicle is lit.

  The night corresponding guidance route calculation processing unit 20 is operated when the user instructs the night corresponding guidance route guidance instruction detecting unit 14 to calculate the night corresponding guidance route, or when the surrounding visibility is poor beforehand. When the initial setting is made to guide the corresponding guidance route, the signal is input, and the vehicle lighting environment detection unit 19 is already in an environment in which the vehicle is already turned on or the vehicle is turned on. Road data that has been used in the past to fetch the guidance route between the current location and the destination input at the current location / destination input unit 12 via the data capture unit 32 when In particular, the road brightness data 31 recorded on the map / information data recording medium 30 in the present invention is used to calculate a night-time guidance route as described later.

  In the vehicle lighting / extinguishing point prediction calculation unit 21, as one function, the vehicle is already turned on or is in an environment where the vehicle is turned on as described above. When a night-time guidance route calculation is performed, whether there is a point where the surroundings become bright and the vehicle lights are turned off between the current location and the destination for that guidance route, and in some cases, that point is approximately Calculate which point. At that time, the sunrise time of the current time detected by the visibility condition detection unit 22, the weather forecast of the surrounding area, the terrain such as whether the surrounding area is a mountainous area or a plain area, etc., is acquired by internal data or information separately acquired by communication means Etc. is input, and a calculation for predicting as accurately as possible a point where a normal guidance route instead of a night guidance route may be guided is performed.

  Further, in the vehicle lighting / light-off point prediction calculation unit 21, as another function, the night correspondence guidance route calculation processing unit 20 temporarily operates because the vehicle is not currently turned on or is not in an environment in which the vehicle is turned on. The normal guidance route calculation unit 15 calculates the normal guidance route, and the normal guidance route calculation is temporarily performed by the normal guidance route calculation unit 15. Calculate the point that needs to be done. In the calculation, the sunset time of the current time detected by the visibility condition detection unit 22 as described above, the weather forecast of the surroundings, the terrain such as whether the surroundings are mountainous parts or plains, etc. are stored in the internal data, or separately communication means Input the information captured in step 1, and perform the prediction calculation of the point that guides the guidance route for night correspondence as accurately as possible.

  As described above, when the vehicle turn-on / light-off point prediction calculation unit 21 calculates the night correspondence route for the first time, it is not necessary to travel on the night correspondence route at dawn while reaching the destination. When it is detected that there is a point that can travel along the guide route, or when a normal guide route is first calculated and the route reaches the destination when traveling along the route, it can be handled at night due to sunset, etc. When it is detected that there is a place where it is preferable to travel the route, the night corresponding guidance route calculation processing unit 20 performs a final guidance route calculation process according to each condition based on each point. Do. When the final guidance route is calculated by the night correspondence guidance route calculation processing unit 20 in this way, after obtaining confirmation by the user, this is stored in the guidance route storage unit 25.

  The night corresponding guidance route calculation unit 16 includes a poorly visible road detection processing unit 23, and when it is necessary to travel on a road with poor visibility even by the calculation of the night correspondence guide route, the visibility in the guidance route is low. A process to detect a point that gets worse is performed. As a result of the processing, when a corresponding point is detected, the visibility deterioration point approach detection unit 24 detects that the point where the visibility deteriorates when the current location is within a predetermined distance, for example, 300 m before the point. In the guidance route guidance output unit 26, an output to that effect is output to the visibility degradation point approach guidance output unit 27, and the visibility degradation point approach guidance output unit 27 is connected via the voice output unit 40. An audio output indicating that the road is dark is output from the speaker 39, or an image indicating that is output from the image output unit 42 to the monitor 41.

  The navigation device shown in FIG. 1 includes various function units similar to those of the conventional navigation device as described above in addition to the guidance route calculation guide processing unit 11 as described above. These various functional units are used. In the data capturing unit 32 shown in FIG. 1, necessary map data and facilities from a map / information data recording medium 30 such as a CD-ROM, DVD-ROM, or hard disk are used. When information is taken in and the data recording medium can be easily written like a hard disk, the data taken from outside or the data processed by other functional units should be read later and used. Data can be input to the data recording medium. In particular, in the map / information data recording medium 30 of FIG. 1, the road brightness data 31 is obtained by using a night-time satellite image as described later, or by another road brightness data collection system. It is created and recorded, and the data is used in the night corresponding guidance route calculation unit 16.

  In the instruction signal input unit 35, an instruction signal for the remote controller 33 or the like by the user in the navigation device is input. Further, a signal of the voice recognition unit 34 that inputs a user instruction signal by processing for recognizing the user's voice as necessary is also input to the instruction signal input unit 35. By the operation of the instruction signal input unit 35, the user can input a destination instruction.

  The external information input unit 36 can input traffic information such as VICS information, for example, and can input various data from an information center or the like by a mobile phone. Information such as the current sunrise / sunset time and weather forecast on the route to the destination can also be captured.

  The vehicle position detection unit 38 inputs the position data of the GPS receiver 37, and further inputs the movement data of the vehicle from the travel distance / orientation detection means by the vehicle speed sensor or the angle sensor as necessary, thereby obtaining the current vehicle position. The position is detected accurately. The current location for the guidance route calculation can be detected by the signal from the vehicle position detector 38.

  A voice is output from the voice output unit 40 to the speaker 39, and information indicating that a point where visibility deteriorates by approaching a guidance route or approaching the poor visibility road is also output. In addition, the image output unit 42 outputs an image to the monitor 41, and displays various information such as a map screen, a vehicle position, and a guide route.

  In the navigation device composed of the functional blocks as described above, the map / information data shown in FIG. 1 is produced by the road brightness data creation process comprising the operation flow shown in FIG. It is written in the recording medium 30 as road brightness data 31, and is used as basic data for calculation and guidance of the night corresponding guidance route. Hereinafter, an example of the process of creating the road brightness data shown in FIG. 2 will be described with reference to FIGS.

  In the road brightness data creation process shown in FIG. 2, first, the nighttime satellite photograph data is enlarged, and the luminance for each minimum unit area is calculated (step S1). That is, as described above, in the field of information collection satellites, there are artificial satellites represented by DMSP in the United States that can observe ground light at night, and information from such satellites can be used in real time. It has become. Although the maximum resolution of DMSP currently in general use is about 1 km, it is predicted that an image with higher resolution can be taken at present.

  The satellite photograph data currently provided is, for example, as shown in FIG. 6. In FIG. 6, the portion shown in white is an area where light such as illumination is present, and the other portions shown in black are This is a region where there is no light such as illumination. In addition, the shade of white indicates the intensity of light, and the higher the brightness in the figure, the more dense the light source such as lighting (actual images are published in the National Geophysical Data Center etc. ). By enlarging this image, brightness data can be obtained by dividing the image into the smallest unit areas, for example, as shown in FIG. .

 Next, the nighttime satellite photograph and the road data are superimposed, and the brightness is calculated from the average luminance for each road link (step S2). FIG. 7 shows an example in which a satellite photograph obtained by DMSP and a road based on road data stored in a map database are overlapped and a part thereof is enlarged. Each square (pixel) represents the minimum unit of a satellite photograph taken at a certain resolution. The example when the road link based on road data is piled up on them is shown.

With this data, when each road link passes through a plurality of areas, the brightness data of each road link can be obtained by calculating the average luminance. That is, as shown in step S2 of FIG.
Brightness of each road link = (total brightness of areas through which each road link passes) / (number of areas through which roads pass)
It can be calculated by the following formula. In addition, in order to obtain the brightness of the road link, in addition to the above method, various conventionally used average value calculation methods can be used.

  As shown in FIG. 8, for example, as shown in FIG. 8, the brightness data of each road link obtained as described above includes information on road brightness necessary for the present invention in addition to various conventional data. In addition to the attributes, roads can be displayed on a map by using such a road link table and a conventional node table, and various information such as brightness data of those roads can be used.

  Usually, road links and nodes are grouped for each unit area (parcel or mesh). The node is point information, and is composed of position information and types of points such as high-speed junctions and general intersections. The road link is road information, and is composed of start / end position information, road length, and road attributes. In general, the start point and end point of a road link are expressed by nodes, and the attributes include the type and width of a road such as a highway and a general road. In addition, when the road link does not include road shape information, the storage destination of the shape link representing the road shape is added to the road link information.

  The navigation device calculates a guide route based on road information stored in these databases. Therefore, when the brightness data as described above is present on the road link, when calculating the guidance route, the brightness information of the road included in the map database is referred to and a coefficient is set so as to reduce the passing cost only for the bright road. By multiplying, it is possible to calculate a guide route that preferentially uses a bright road.

  Next, in the example shown in FIG. 2, each road link is sorted into an urban area and other areas (step S <b> 3). When the link exists in the urban area, the process proceeds to step S5, and it is determined whether or not the brightness of the road link is equal to or higher than a first predetermined value A1 (> A2) that is a relatively bright value. On the other hand, when it is determined in step S4 that it is not an urban area, it is determined whether or not the brightness of the road link is equal to or higher than a first predetermined value A2 (<A1) that is a relatively dark value (step S4). S8). Here, the first predetermined value A1 is brighter than the second predetermined value A2.

  In step S5, when it is determined that the brightness of the road link is equal to or higher than the first predetermined value A1, the road is determined to be a bright road (A1U), and is determined not to be higher than the first predetermined value A1. When it is done, it is determined as a dark road (A1B). In step S8, when it is determined that the brightness of the road link is equal to or higher than the second predetermined value A2, the road is determined to be a bright road (A2U), and is not determined to be higher than the second predetermined value A2. When it is done, it is determined as a dark road (A2B).

  Depending on whether or not the road link is in an urban area, the criteria for separating a bright road from a dark road, that is, a standard that defines the brightness, is different when a vehicle driver travels in an urban area. Because it is driving on a sufficiently bright road by surrounding shops and street lights, it feels very dark even if it gets a little dark, and conversely when driving on a road that is relatively dark and is not urban, This is to cope with the tendency to recognize that the road is sufficiently bright just by driving on a slightly bright road. Further, the road brightness data stores road brightness information in a map database for each time zone, and the night corresponding guidance route calculation means uses the road brightness data according to the travel time. A guide route may be calculated by selecting a bright road.

  A flag is assigned to each road link according to the results of these various calculations and determinations (step S11). At that time, the average brightness is recorded on each road link, and the data can be used later. Further, data or a flag indicating whether each road is a bright road or a dark road is also recorded. This is used for output reference data for caution guidance for the driver when traveling. Brightness data in consideration of whether it is an urban area such as (A1U), (A1B), (A2U), (A2B), etc. determined in steps S6, 7, 9, 10 as road brightness data at that time May be recorded.

  As a result of the processing as described above, in the present invention, the road brightness data 31 is stored for each road link in the CD-ROM, DVD-ROM, hard disk or the like as the map / information data recording medium of FIG. The data as described above will be recorded, and in particular, the night correspondence guidance route calculation unit 16 will use this data effectively.

In the navigation apparatus to which the present invention is applied, guidance data for the guidance route can be performed by using such data, for example, by an operation flow as shown in FIG. In the example shown in FIG. 3, at the time of guidance route guidance processing, the current location and destination are first input (step S11), and then the guidance route calculation instruction is issued (step S12), as in the prior art.
Thereafter, it is determined whether or not there is a nighttime guidance route guidance instruction (step 13). If it is determined that there is a nighttime guidance route guidance instruction, the process proceeds to step S14 to calculate the nighttime guidance route guidance shown in FIGS. Process.

  In determining whether or not there is a night-time guidance route guidance instruction, when performing a guidance route calculation instruction, the user has given an instruction corresponding to the night-direction guidance route request instruction unit displayed on the monitor. This can be determined by detection, or may be detected in advance in the initial setting of the navigation apparatus when the guidance route for night is also presented when the guidance route is presented.

  In the determination processing, when the user's various calculation instructions are input in the guidance route calculation instruction input unit 13 in the guidance route calculation guidance processing unit 11 of FIG. The determination is made by detecting the presence / absence of a guidance instruction for a guidance route corresponding to the night in the instruction. Further, when the night corresponding guidance route guidance instruction detecting unit 14 detects that there is a guidance instruction for the night corresponding guidance route, the signal is output to the night corresponding guidance route calculating unit 16 to output the night corresponding guidance route calculating unit. In FIG. 16, the processes shown in FIGS. 4 and 5 are performed in order.

  In the night-time guidance route calculation process shown in FIG. 4, first, the current lighting environment of the vehicle is detected and input (step S31), and then whether or not the current vehicle is lit or whether a lighting environment is generated or not is determined. It discriminate | determines (step S32). This processing is performed in a vehicle equipped with this navigation device, such as when the vehicle lighting detection unit 17 in the night corresponding guidance route calculation unit 16 in FIG. 1 inputs a signal from an in-vehicle LAN that controls various devices of the vehicle. This is done by detecting whether or not lights such as headlamps are turned on. Also, when this vehicle is equipped with an outside illuminance meter 18, the brightness of the outside of the vehicle lights up the lights such as the headlamps of the vehicle. However, it can be performed by detecting the presence or absence of darkness of a good degree.

  In addition, it may be set in advance so that the data of the illuminance meter outside the vehicle is always input and the night corresponding guidance route is calculated when the surroundings become dark. Furthermore, it is possible to automatically set a night-time guidance route when a headlight breaks down, and to select and set a repair shop or the like as close as possible to the destination.

  When it is determined in step S32 that the current vehicle is lit or is in an lit environment, the process proceeds to step S38, and the current location is set as the vehicle lighting point in the vehicle lighting / predicted point setting. On the other hand, if it is determined in the determination that the current vehicle is not lit or is not in a lighting environment, the process proceeds to step S33, and a normal guidance route is provisionally calculated. In this process, when the vehicle lighting environment detection unit 19 in FIG. 1 detects that the current vehicle is not lit or is not in a lighting environment, the signal is output to the night corresponding guidance route calculation processing unit 20. The night correspondence guidance route calculation processing unit 20 can perform the normal guidance route provisional calculation function performed before the night correspondence guidance route calculation processing provided as one of the functions. In addition, when the vehicle lighting environment detection unit 19 detects that the current vehicle is not lit or is not in a lighting environment, the signal is output to the normal guidance route calculation unit 15, and the normal vehicle obtained there is obtained. It is also possible to take in a guide route and use it.

  Next, in step S34, various conditions such as terrain, sunset time, and weather on the temporary normal guidance route are captured. A part of the information can be recorded in advance on a hard disk or the like as the map / information data recording medium 30 in FIG. 1, and can be read by reading it from the external information input unit 36 via a mobile phone or the like. It can also be performed by connecting to an information center and taking in information for night guidance route calculation set in advance.

  Thereafter, in step S35, the estimated lighting time of the vehicle is calculated from various conditions on the travel route. In this calculation, the present time is detected by detecting the current time, calculating the predicted arrival time of each point on the guidance route, and detecting whether it is a mountainous area or a plain from the terrain data of those points. Then, the weather forecast data of those points at the predicted time of passage of those points is used to detect whether it is sunny, cloudy, or rainy, and the occurrence of sunset at each point is referenced with reference to the current standard sunset time. The time when the vehicle is to be turned on is predicted and calculated by detecting the presence or absence.

  The time when the vehicle is turned on is a time having the same meaning as the time when it is determined that it is better for the driver to travel on a bright road with poor visibility. In addition, it is conceivable that the nighttime brightness may change depending on the time zone, such that the residential area is bright from evening to night and dark at midnight, so it is preferable to input these conditions.

  Next, in the example of FIG. 4, the position of the vehicle turn-on required time with respect to the predicted destination arrival time is determined (step S36). When it is determined that the destination arrival predicted time is not before, the process proceeds to step S39. The provisional normal guidance route obtained as described above is set as a guidance route, and then the process proceeds to step S52 in FIG. 5 to determine the guidance route. In other words, when traveling on the current temporary normal guidance route, it is determined here that it is possible to arrive at the destination before the surrounding visibility deteriorates unless there is a traffic jam or the like. The normal guide route is set as the guide route, and as a result, the same guide route as that obtained by the conventional guide route calculation is set.

  If it is determined in step S36 that the required lighting time of the vehicle is before the estimated arrival time at the destination, the temporarily calculated normal guidance route is calculated at the required lighting time of the vehicle as described above. The vehicle travel point at is predicted and calculated (step S37). These processes are performed by inputting various data of the visibility condition detection unit 22 and performing calculations in the vehicle lighting / light-off point prediction calculation unit 21 of FIG.

  In step S37, when a point where the surroundings are darkened to some extent that the vehicle needs to be lit is calculated on the calculated normal guidance route, the point is set as a predicted lighting point of the vehicle. If it is determined in step S32 that the current vehicle is already lit or is in an lit environment, the current location is set as the vehicle lighting point (step S38).

  Thereafter, the process shown in FIG. 5 is continued, and a night temporary guidance route from the vehicle lighting predicted point to the destination is calculated (step S40). That is, when the surrounding visibility is already poor, or when there is a point where the surrounding visibility is deteriorated during traveling, the night guidance route is calculated. However, in the guidance route corresponding to the night, it is considered that it is not necessary to travel on the guidance route corresponding to the night when the guidance route travels as the night breaks, as described later. Is calculated. These calculations are performed as one of various calculation functions in the night corresponding guidance route calculation processing unit 20 of FIG.

  Next, it is determined whether the nighttime temporary guidance route calculated as described above is identical to the previously calculated temporary normal guidance route (step S41). Here, when the night temporary guidance route is different from the temporary normal guidance route, that is, the night correspondence route obtained using the road brightness data according to the present invention is different from the normal guidance route and is useful. In some cases, it is set as a night-time guidance route.However, considering that it may be better to travel on a normal guidance route due to the dawn of the night, etc. As a night-time guidance route.

  If it is determined in step S41 that the nighttime temporary guidance route is not different from the temporary normal guidance route, that is, they are the same, the temporary normal guidance route obtained previously is temporarily used for the future calculation. A route is set (step S42). When it is determined in step S41 that the night temporary guide route is different from the temporary normal guide route, the night temporary guide route data is used. In step S42, the temporary normal guide route is the night temporary guide route. Using the guidance route data, conditions such as terrain, sunrise time, weather, etc. on the night temporary guidance route are taken in by the same method as in step S34 in FIG. 4 (step S43).

  When it is determined in step S41 that the nighttime temporary guidance route is the same as the temporary normal guidance route, various data on the route are captured in step S34. In this example, the sunrise time is particularly captured here. . However, when the sunrise time is already captured in step S34, it is not particularly necessary to capture the data again here.

  Next, the predicted turn-off time of the vehicle is calculated from the various conditions on the travel route (step S44). Note that the predicted turn-off time of the vehicle is a time when the driver thinks that the driver may turn off when the surrounding headlights are turned on and the surrounding visibility is improved. It is the same purpose as the time of getting better.

  Thereafter, the position of the predicted turn-off time of the vehicle with respect to the predicted arrival time at the destination is determined (step S45), and when it is determined that it is before, the vehicle travel point at the predicted turn-off time of the vehicle is predicted and calculated (step S46). This can be performed by the same method as in step S37 of FIG. Next, the predicted turn-off point of the vehicle obtained by the above calculation is set (step S47), and the normal guidance route from the predicted turn-off point of the vehicle to the destination is calculated (step S48). In other words, when the night-time guidance route is running and the surroundings become brighter and the surroundings become brighter and the visibility is improved, it is not necessary to travel on the night-time guidance route, which tends to be more detour than the normal guidance route. Since it is only necessary to travel on the route, calculation for traveling on the normal guidance route is performed from here.

  As a result of the calculation, the identity of the normal guidance route from the predicted vehicle extinction point to the destination with the previously obtained temporary guidance route for night is determined (step S49). This discrimination is the same as in step S41. When it is discriminated here, that is, when a normal guidance route that seems to be better than the night guidance route is obtained, a new guidance from the current location to the destination is obtained. The route is set as a night corresponding guidance route (step S50). On the other hand, when it is determined in step S45 that the predicted turn-off time of the vehicle is not before the predicted arrival time of the destination, that is, the day before reaching the destination is not dawn, and the predicted turn-off point of the vehicle in step S49. When it is determined that the normal guidance route from the destination to the destination is not different from the nighttime temporary guidance route, that is, the same route, the process proceeds to step S51, where the nighttime temporary guidance route is set as the nighttime guidance route.

  In step S39 of FIG. 4, the temporary normal guidance route is set as the guidance route, in step S50, the new guidance route is set as the night correspondence route, and in step S51, the night temporary guidance route is set as the night correspondence route. In either case, the guidance route determination process is performed in step S52 (step S52), and the series of night-time guidance route calculation processes shown in FIGS.

  In step S14 in FIG. 3, the night-time guidance route calculation process is performed as described above, and after the guidance route is determined, guidance is provided so that the vehicle can travel safely along the guidance route (step S15). ). Thereafter, it is determined whether or not a dark road with poor visibility is approached within a predetermined distance (step S16). As a result of the determination, when it is determined that a dark road with poor visibility is approached within a predetermined distance such as 300 m, the process proceeds to step S17, and the distance to that road is confirmed as approaching a dark road with poor visibility. Etc. These processes detect that the road detected by the poor-visibility road detection processing unit 23 in FIG. 1 is within a predetermined distance at the point where the visibility-deteriorating point approach detection unit 24 will travel on the road. This is performed by externally outputting from the visibility deterioration point approach guidance output unit 27 of the guidance route guidance output unit 26. As a guidance output for the user, for example, when driving on a dark road with poor visibility, the distance to a bright road with good visibility may be guided.

  After performing such guidance, if it is determined in step S16 that the road is not yet close to the road with poor visibility within a predetermined distance, it is determined whether or not the vehicle has arrived at the destination (step S18). When it has not arrived at the ground, the process returns to step S15 to continue the travel guidance according to the previous guidance route and repeat the operation.

  In step S13, when it is determined that there is no guidance instruction for the night corresponding guidance route from the user or the like, the process proceeds to step S19, where the normal guidance route calculation processing is performed in the same manner as before, and then the normal guidance route is determined. Confirmation is made (step S20), travel guidance is performed according to the guidance route (step S21), the presence / absence of arrival at the destination is determined (step S22), and if the destination has not yet been reached, the process returns to step S21. Continue driving guidance on the normal guidance route. When it is determined in steps S18 and S22 that the vehicle has arrived at the destination, the guidance route guidance processing is terminated (step S23).

  In the present invention that operates as described above, when a bright road and a dark road exist between the current position of the vehicle and the destination, for example, as shown in FIG. ), A route having a short travel distance is set as a guide route regardless of the brightness of the road as indicated by a thick black line. However, in the present invention, when the user desires to travel on the brightest road, As shown by the thick broken line in FIG. 5B, it becomes possible to travel by selecting a bright road that is slightly detoured. By using such a bright road, the user's mental burden can be reduced and driving safety can be ensured.

  In the above example, the guide route for night correspondence was calculated before the departure of the vehicle, and the travel guidance was shown accordingly, but in addition, as when the surroundings became dark during traveling on the normal guide route In addition, even when the user suddenly needs to present a night-time guidance route, by performing an instruction to that effect, the night-time guidance route from the current location to the destination is calculated and presented in the same manner. be able to.

  Further, in the above embodiment, when the guidance instruction for the night-time guidance route is given, an example is given in which guidance is given when approaching a road with poor visibility while the vehicle is running. Even when driving on a normal guidance route where guidance is not being used, the brightness data of the road can be used effectively so that when approaching a low-visibility road, guidance to that effect is given. good.

  Normally, navigation devices are often used when going to unfamiliar destinations, but the present invention is used when the surroundings are dark even in the user's living sphere, so that pedestrians can jump out and on the road. It becomes possible to avoid dangers such as parked cars.

  It is possible to calculate the route using the brightest road according to the time of passing the road by providing multiple time zones for taking satellite photos and storing the brightness of the road for each specific time zone .

  In addition, when traveling in areas where the map is not well prepared overseas such as by storing mesh-like luminance information in a database and overlaying satellite images at night on the map displayed by the navigation system However, the user can travel while selecting a bright area as much as possible.

  Further, the brightness of the road may be expressed on the map by changing the saturation of the color of the road, for example, using the brightness information of the road included in the map database. As a result, the present invention can be implemented in various ways, such as when the user has no guidance route, that is, even when the destination is not set, the user can select and travel on the brightest road possible. .

  Furthermore, the present invention can also be realized by adding to the map database data on the installation location of streetlights managed by various local governments or the installation location of streetlights described on the map.

  In addition to the navigation device mounted on the vehicle, the present invention can be similarly applied to various devices having a navigation function, such as a navigation device brought into the vehicle and used, or a mobile phone having the same function. .

It is a functional block diagram of the Example of this invention. It is an operation | movement flowchart which performs the preparation process of the brightness data of the road in the Example. It is an operation | movement flowchart which performs the guidance process of the guidance path | route in the Example. It is an operation | movement flowchart which performs the calculation process of the night corresponding | compatible guidance path | route in FIG.3 S14. It is an operation | movement flowchart performed following step S38 of FIG. It is a figure which shows the example of the night ground image by DMSP. It is a figure which shows the example of the road superimposed on the brightness data for every mesh obtained by the analysis of the captured image, and it. It is a figure which shows the example of the road link table and node table utilized when calculating a guidance route. (A) shows an example of a bright road and a dark road in the road from the present location to the vicinity of the destination, and (b) shows a guide route obtained by giving priority to the bright road obtained by the present invention in the road, It is a figure which compares and shows the guide route of.

Explanation of symbols

11 Guidance route calculation guidance processing section
12 Current location / destination input unit 13 Guidance route calculation instruction input unit 14 Night-time guidance route guidance instruction detection unit 15 Normal guidance route calculation unit 16 Night-time guidance route calculation unit 17 Vehicle lighting detection unit 18 Outside illumination meter 19 Vehicle lighting environment detection Unit 20 Night corresponding guidance route calculation processing unit 21 Vehicle lighting / extinguishing point prediction calculation unit 22 Visibility condition detection unit 23 Visibility poor road detection processing unit 24 Visibility deterioration point approach detection unit 25 Guidance route storage unit 26 Guidance route guidance output Part 27 Visibility deterioration point approach guidance output part 31 Brightness data

Claims (5)

A map database that records road brightness data;
Using the road brightness data of the map database, a night corresponding guidance route calculating means for calculating a guidance route giving priority to a bright road,
Vehicle ambient brightness detection means for detecting the ambient brightness of the vehicle,
A night driving assistance navigation device, wherein when the vehicle surrounding brightness detecting means detects that the surrounding is dark, the night corresponding guidance route calculating means calculates a guidance route giving priority to a bright road.   2. The night driving assistance navigation apparatus according to claim 1, wherein the road brightness data is obtained by calculating the brightness of a road from a night satellite photograph and storing it in a map database. 3. The night driving assistance navigation apparatus according to claim 2, wherein information on the night satellite photograph is stored in a map database and displayed superimposed on the map.   The night driving assistance navigation apparatus according to claim 1, wherein the road brightness data is obtained by changing a standard for defining road brightness in an urban area and other areas. The road brightness data stores road brightness information in a map database for each time period,
2. The night driving assistance navigation apparatus according to claim 1, wherein the night corresponding guidance route calculation means calculates the guidance route by selecting a bright road according to the driving time using the brightness data of the road.

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