Aboveground data collection device, aboveground data collection method, and computer program for aboveground data collection

Abstract

The present invention relates to a ground object data collection device, a ground object data collection method, and a computer program for ground object data collection. The ground object data collection device includes: a storage unit (32, 33) for storing, for each of the plurality of vehicles (2), the amount of ground object data representing ground objects associated with the vehicle's travel or the travel distance of the vehicle transmitted by that vehicle; a transmission condition setting unit (43) for setting transmission conditions for each of the plurality of vehicles (2) in such a way that the transmission conditions allowing the transmission of ground object data are more relaxed for vehicles with shorter travel distances or vehicles that transmit less ground object data; and a notification unit (44) for notifying each of the plurality of vehicles (2) of a collection instruction to collect ground object data under the transmission conditions set for that vehicle via a communication unit (31).

Description

Technical Field

[0001] This invention relates to a ground feature data collection device, a ground feature data collection method, and a computer program for collecting ground feature data, which collects data on ground features presented on a map. Background Technology

[0002] In the high-precision maps referenced by autonomous driving systems for controlling vehicles, it is required to accurately represent information related to ground features located on or around roads that are associated with vehicle movement. Therefore, a technique for collecting data representing ground features from vehicles actually traveling on roads has been proposed (see International Publication No. 2017 / 212639).

[0003] In the technology disclosed in International Publication No. 2017 / 212639, the server device stores a height-ratio map containing information about ground features in a storage unit. Then, the server device receives difference information from multiple vehicle-mounted units equipped with external sensors measuring ground features, indicating the differences between the ground feature information and the actual ground features corresponding to that information. Furthermore, based on a reliability calculated from the multiple difference information, the server device sends an original data request signal to the vehicle-mounted units, requesting the transmission of original data as measurement data of the actual ground features. Summary of the Invention

[0004] The more data representing objects on the ground is sent from vehicles to the server, the higher the cost associated with the wireless communication used for this data collection becomes. In particular, the unit communication cost for vehicles exceeding a certain communication volume is sometimes set higher than the unit communication cost for vehicles not exceeding that volume. Therefore, it is desirable to even out the amount of data representing objects on the ground sent from each vehicle to the server.

[0005] Therefore, the object of the present invention is to provide a ground object data collection device that can equalize the amount of ground object data transmitted by each vehicle.

[0006] According to one embodiment, a ground object data collection device is provided. This ground object data collection device includes: a storage unit for storing, for each of a plurality of vehicles, the amount of ground object data representing ground objects associated with the vehicle's travel, or the travel distance of the vehicle; a transmission condition setting unit for setting transmission conditions for each of the plurality of vehicles in a manner that makes the transmission conditions for allowing ground object data transmission more lenient for vehicles with shorter travel distances or vehicles transmitting less ground object data; and a notification unit for notifying each of the plurality of vehicles, via a communication unit, of a collection instruction instructing the collection of ground object data under the transmission conditions set for that vehicle.

[0007] In this aboveground object data collection device, the transmission condition setting unit preferably sets the transmission conditions in a way that allows the transmission of aboveground object data to be carried out in the form of vehicles with shorter travel distances among multiple vehicles, vehicles with less data to be transmitted, and areas with higher traffic volume among multiple areas that are the targets of aboveground object data collection.

[0008] In this case, the above-ground object data collection device preferably further includes: a vehicle classification unit, which classifies multiple vehicles into any of a plurality of distance classification levels based on the travel distance of each vehicle; and a region classification unit, which classifies multiple regions into any of a plurality of traffic volume classification levels based on the traffic volume of each region. Furthermore, the region classification unit preferably sets transmission conditions such that the shorter the average travel distance of each vehicle within the distance classification level, the more likely the transmission of above-ground object data is to be allowed even in regions belonging to traffic volume classification levels with higher traffic volume.

[0009] Alternatively, the storage unit preferably stores, for each of the multiple areas that are the targets of the collection of above-ground object data, the amount of above-ground object data received from any vehicle among the multiple vehicles during a specified period and the target collection amount of above-ground object data. Furthermore, the transmission condition setting unit preferably sets the transmission conditions in a manner that allows the transmission of above-ground object data to be made in areas where the ratio of the amount of above-ground object data received to the target collection amount is higher than that of vehicles with shorter travel distances among the multiple vehicles or vehicles with less transmitted above-ground object data, and in areas where the ratio of the amount of above-ground object data received to the target collection amount is higher.

[0010] According to other methods, a method for collecting ground object data is provided. This method includes: setting transmission conditions for each of the multiple vehicles in a manner that relaxes the transmission conditions allowing the transmission of ground object data, particularly for vehicles with shorter travel distances or vehicles transmitting less ground object data associated with the vehicle's travel; and, for each of the multiple vehicles, notifying the vehicle via a communication unit of a collection instruction to collect ground object data under the transmission conditions set for that vehicle.

[0011] Furthermore, according to other methods, a computer program for collecting ground object data is provided. This computer program for collecting ground object data includes commands that cause the computer to: set transmission conditions for each of the multiple vehicles in a manner that relaxes the transmission conditions allowing the transmission of ground object data, particularly for vehicles with shorter travel distances or vehicles transmitting less ground object data associated with the travel of a vehicle; and, for each of the multiple vehicles, notify the vehicle via a communication unit of a collection instruction to collect ground object data under the transmission conditions set for that vehicle.

[0012] The ground object data collection device of the present invention has the effect of equalizing the amount of ground object data transmitted by each vehicle. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a ground object data collection system with a ground object data collection device installed.

[0014] Figure 2 It is a schematic diagram of the vehicle's structure.

[0015] Figure 3 This is a hardware structure diagram of the data acquisition device.

[0016] Figure 4 This is a hardware structure diagram of a server, which serves as an example of a data collection device for ground objects.

[0017] Figure 5 This is a functional block diagram of the processor of the server related to the collection and processing of data on aboveground objects.

[0018] Figure 6 This is a diagram illustrating an example of the relationship between traffic volume levels set for each area and the driving distance levels that allow the transmission of surface data.

[0019] Figure 7 This is a flowchart of the action process for collecting and processing data on above-ground objects. Detailed Implementation

[0020] Hereinafter, with reference to the accompanying drawings, a ground feature data collection device, a ground feature data collection method executed by the ground feature data collection device, and a computer program for ground feature data collection are described. This ground feature data collection device collects data (hereinafter referred to as ground feature data) representing ground features associated with vehicle movement from multiple communicating vehicles, relating to multiple areas presented on a map that is the object of generation or updating.

[0021] For each vehicle, the distance traveled within a given period varies. Assuming all vehicles transmit ground object data under identical conditions, generally, vehicles traveling longer distances transmit more ground object data. Therefore, the cost of wireless communication for vehicles with longer travel distances increases. To even out the amount of ground object data transmitted by each vehicle, an upper limit on the amount of data that can be transmitted wirelessly is considered. However, vehicles with longer travel distances are more likely to be traveling on roads where ground object data collection is difficult—roads where such vehicles would be unusable. Therefore, when the transmission of ground object data from vehicles with longer travel distances is restricted, collecting ground object data on these difficult-to-collect roads becomes even more challenging.

[0022] Therefore, the ground object data collection device stores the travel distance of each of the multiple vehicles. The device sets transmission conditions for each vehicle in a manner that makes the transmission conditions for allowing ground object data transmission more lenient for vehicles with shorter travel distances. Then, the device notifies each vehicle via its communication unit of a collection instruction to collect ground object data under the set transmission conditions. Specifically, the device sets transmission conditions based on geographical area. In this embodiment, the device classifies multiple areas presented on the map (which is the object of generation or updating) that are the targets of ground object data collection according to traffic volume. Furthermore, for vehicles with shorter travel distances, the device sets a higher upper limit on traffic volume for the level of the area where ground object data transmission is permitted.

[0023] In addition, the ground objects that are the subjects of the inspection include various road signs, traffic lights, and ground objects that are associated with the movement of other vehicles.

[0024] Figure 1 This is a schematic structural diagram of a ground object data collection system equipped with a ground object data collection device. In this embodiment, the ground object data collection system 1 includes multiple vehicles 2 and a server 3, which is an example of a ground object data collection device. Each vehicle 2 connects to the server 3, for example, by accessing a wireless base station 5 connected to a communication network 4 via a gateway (not shown) and thus via the wireless base station 5 and the communication network 4. Furthermore, in Figure 1 For simplicity, only one vehicle, 2, is shown in the diagram. Similarly, in Figure 1 The diagram shows only one wireless base station 5, but multiple wireless base stations 5 may be connected to the communication network 4. Additionally, the server 3 may also be communicatively connected to a traffic information server (not shown) that manages traffic information via the communication network.

[0025] In this embodiment, each vehicle 2 has the same structure and function for collecting data on above-ground objects. Therefore, one vehicle 2 will be described below.

[0026] Figure 2 This is a schematic diagram of vehicle 2. Vehicle 2 includes a camera 11, a GPS receiver 12, a wireless communication terminal 13, and a data acquisition device 14. The camera 11, GPS receiver 12, wireless communication terminal 13, and data acquisition device 14 are communicatively connected via an in-vehicle network following a standard controller area network (CLAN). Additionally, vehicle 2 may also include a navigation device (not shown) that searches for a predetermined route for vehicle 2, navigating the vehicle 2 along that route.

[0027] Camera 11 is an example of a camera unit used to photograph the area around vehicle 2. It has a 2D detector composed of an array of photoelectric conversion elements sensitive to visible light, such as CCD or C-MOS, and an imaging optical system that images the area to be photographed onto the 2D detector. Camera 11 is then mounted, for example, in the interior of vehicle 2, facing forward of vehicle 2. Camera 11 then photographs the area in front of vehicle 2 at predetermined shooting intervals (e.g., 1 / 30 to 1 / 10 of a second), generating an image of that area. The image obtained by camera 11 can be either a color image or a grayscale image. Alternatively, multiple cameras 11 with different shooting directions or focal distances may be provided in vehicle 2.

[0028] Whenever a camera 11 generates an image, it outputs the generated image to the data acquisition device 14 via the in-vehicle network.

[0029] GPS receiver 12 receives GPS signals from GPS satellites at predetermined intervals and determines the vehicle 2's own position based on the received GPS signals. Then, at predetermined intervals, GPS receiver 12 outputs positioning information, representing the positioning result of the vehicle 2's own position based on the GPS signals, to data acquisition device 14 via the in-vehicle network. Alternatively, vehicle 2 may have a receiver that follows a satellite positioning system other than GPS receiver 12. In this case, the receiver can determine the vehicle 2's own position.

[0030] The wireless communication terminal 13, an example of a communications unit, is a device that performs wireless communication processing following prescribed wireless communication standards. For example, it connects to the server 3 via the wireless base station 5 and the communication network 4 by accessing the wireless base station 5. The wireless communication terminal 13 then generates an uplink wireless signal received from the data acquisition device 14, containing ground object data or driving information indicating the distance traveled by the vehicle 2. The wireless communication terminal 13 then transmits this uplink wireless signal to the wireless base station 5, thereby sending the ground object data and driving information to the server 3. Additionally, the wireless communication terminal 13 receives downlink wireless signals from the wireless base station 5 and delivers collection instructions from the server 3 contained in these signals to the data acquisition device 14 or an electronic control unit (ECU, not shown) that controls the movement of the vehicle 2.

[0031] Figure 3 This is a hardware structure diagram of the data acquisition device. The data acquisition device 14 generates ground object data based on images generated by the camera 11. Furthermore, the data acquisition device 14 generates driving information for the vehicle 2. For this purpose, the data acquisition device 14 has a communication interface 21, a memory 22, and a processor 23.

[0032] Communication interface 21 is an example of an in-vehicle communication unit, having an interface circuit for connecting the data acquisition device 14 to the in-vehicle network. Specifically, communication interface 21 connects to the camera 11, GPS receiver 12, and wireless communication terminal 13 via the in-vehicle network. Then, whenever communication interface 21 receives an image from the camera 11, it delivers the received image to processor 23. Additionally, whenever communication interface 21 receives location information from the GPS receiver 12, it delivers the received location information to processor 23. Furthermore, communication interface 21 outputs ground object data and driving information received from processor 23 to wireless communication terminal 13 via the in-vehicle network.

[0033] The memory 22 may include, for example, volatile semiconductor memory and non-volatile semiconductor memory. The memory 22 may also include other storage devices such as hard disk drives. The memory 22 stores various data used in the processing associated with the generation of ground object data, executed by the processor 23 of the data acquisition device 14. Such data includes, for example, road maps, vehicle 2 identification information, camera 11 parameters such as setup height, shooting direction, and field of view, and parameter sets for determining the identifier used to detect ground objects from images. Furthermore, the road map may be, for example, a map used in a navigation device, containing information such as the location, length, and connection relationships of road sections within the area presented by the road map. Additionally, the memory 22 may store images received from the camera 11 and positioning information received from the GPS receiver 12 for a certain period. Furthermore, the memory 22 stores information indicating the area designated as the object of ground object data generation and collection (hereinafter, sometimes referred to as the collection object area) according to the ground object data collection instructions. Furthermore, the memory 22 may also store computer programs for implementing the various processes executed by the processor 23.

[0034] The processor 23 has one or more CPUs (Central Processing Units) and their peripheral circuitry. The processor 23 may also include other arithmetic circuits such as logic units, numerical processing units, or graphics processing units. The processor 23 then stores the images received from the camera 11 and the positioning information received from the GPS receiver 12 in the memory 22. Furthermore, during the movement of the vehicle 2, the processor 23 performs processing related to the generation of ground object data at predetermined intervals (e.g., 0.1 seconds to 10 seconds).

[0035] Processor 23 performs processing associated with the generation of ground object data, for example, determining whether the vehicle 2's location, indicated by positioning information received from GPS receiver 12, is included in the target collection area. Then, if the vehicle's location is included in the target collection area, processor 23 generates ground object data based on images received from camera 11.

[0036] For example, processor 23 may use the image itself (hereinafter, sometimes referred to as the overall image) received from camera 11 as ground object data. Alternatively, processor 23 may extract a portion of the overall image received from camera 11, including the area where the road surface is presented, and use this extracted portion as ground object data. Furthermore, information indicating the area presumed to be where the road surface is presented in the overall image may be stored in memory 22 beforehand. Then, processor 23 may determine the area extracted from the overall image by referring to the information indicating that area.

[0037] Alternatively, processor 23 can detect ground objects presented in the input whole image or partial image (hereinafter, sometimes simply referred to as the input image) by inputting the whole image or partial image into a recognizer pre-learned to detect ground objects as detection targets. Processor 23 can then generate information representing the types of detected ground objects as ground object data. Processor 23 can function as such a recognizer, for example, using a deep neural network (DNN) pre-learned to detect ground objects presented in the input image. Such a DNN could be, for example, a Single Shot MultiBox Detector (SSD) or a Faster R-CNN with a convolutional neural network (CNN) architecture. In this case, the recognizer calculates a confidence level representing the probability that a ground object is present in each region of the input image for each type of ground object (e.g., lane markings, pedestrian crossings, temporary stop lines, etc.). The recognizer determines that a ground object of that type is present in a region where the confidence level for any type of ground object is above a predetermined detection threshold. Then, the recognizer outputs information representing the region on the input image that includes the ground objects that are to be detected (e.g., the bounding rectangle of the ground objects that are to be detected, hereinafter referred to as the object region) and information representing the type of ground objects presented in the object region. Thus, the processor 23 can generate ground object data in a manner that includes information representing the type of ground objects presented in the detected object region.

[0038] Furthermore, the processor 23 determines the location of the ground object data or the position of the ground object in actual space, and includes information indicating that location in the ground object data. For example, the processor 23 uses the vehicle 2's own position when generating the image used to generate the ground object data as the location of the ground object data. In this case, the processor 23 can use the location information received from the GPS receiver 12 at the most recent timing when generating the image used to generate the ground object data as the vehicle 2's own position. Alternatively, if the ECU (not shown) estimates the vehicle 2's own position, the processor 23 can also obtain information indicating the estimated vehicle 2's own position from the ECU via the communication interface 21. Furthermore, the processor 23 can obtain information indicating the vehicle 2's direction of travel from the ECU (not shown). In addition, the position of each pixel in the image corresponds one-to-one with the orientation of the object presented from the camera 11 to that pixel. Therefore, when the ground object data is a whole image or a partial image, the processor 23 can also estimate the position in actual space corresponding to the center of the whole image or partial image as the location of the ground object data. In this case, the processor 23 infers the location corresponding to the center of the overall image or a portion of the image based on parameters such as the orientation from the camera 11, the vehicle 2's own position, the vehicle 2's direction of travel, and the camera 11's shooting direction, field of view, and setting height. Alternatively, if the ground object data contains information indicating the type of ground object detected, the processor 23 infers the location of the ground object in that object area based on the orientation from the camera 11 corresponding to the center of gravity of the detected object area, the vehicle 2's own position, direction of travel, and the camera 11's parameters. Alternatively, the processor 23 can also use so-called Structure from Motion (SfM) to infer the location of the ground object presented in the ground object data. In this case, the processor 23 uses optical flow to correlate object areas presenting the same ground object between two images obtained at different timings. Then, the processor 23 can infer the location of the ground object by triangulation based on the vehicle 2's position and direction of travel when the two images were obtained, the camera 11's parameters, and the location of the object area in each image.

[0039] The processor 23 includes the latitude and longitude of the location or position of the ground object presented in the ground object data as information indicating the location or position of the ground object presented in the ground object data. Furthermore, the processor 23 refers to a road map to determine the location or position of the ground object presented in the ground object data, or the road segment closest to that location. Then, the processor 23 can include the identification number of the determined road segment in the ground object data. Furthermore, if the ground object data is a complete image or a partial image, the processor 2 can also include the position and direction of travel of the vehicle 2 at the time of image generation, as well as the parameters of the camera 11, in the ground object data in a way that allows the server 3 to infer the position of the ground object presented in the complete image or partial image.

[0040] Furthermore, processor 23 can also generate two or more types of ground object data, including overall images, partial images, and information indicating the types of ground objects. Additionally, processor 23 can change the type of ground object data generated based on the position of vehicle 2 at the time of data generation. In this case, category specification information for the type of ground object data to be collected, for each collection target area, is included in the collection instruction received from server 3. Then, processor 23 determines the type of ground object data to be generated by referring to this category specification information. Alternatively, the type of ground object data to be generated can be changed based on the road environment surrounding vehicle 2. For example, if vehicle 2 is within a specified distance from an intersection, processor 23 can use the overall image as ground object data; if vehicle 2 is outside the specified distance, it can use a partial image or information indicating the types of ground objects as ground object data. In this case, processor 23 determines whether vehicle 2 is within the specified distance from an intersection by referring to the road map stored in memory 22 and the vehicle's own position.

[0041] Furthermore, the processor 23 incorporates the vehicle 2's identification information into the ground object data. Then, whenever ground object data is generated, the processor 23 outputs the generated ground object data to the wireless communication terminal 13 via the communication interface 21. Thus, the ground object data is sent to the server 3.

[0042] Additionally, processor 23 generates driving information at a predetermined time. This predetermined time can be, for example, set to the time when the ignition switch of vehicle 2 is turned off. In this case, when the ignition switch of vehicle 2 is turned on, processor 23 obtains information indicating the total driving distance of vehicle 2 from the ECU (not shown) and stores this total driving distance as the total driving distance at the start of driving in memory 22. Then, when the ignition switch of vehicle 2 is turned off, processor 23 again obtains information indicating the total driving distance of vehicle 2 from the ECU and stores this total driving distance as the total driving distance at the end of driving. Then, processor 23 generates driving information in such a way that the difference between the total driving distance at the end of driving and the total driving distance at the start of driving is included as the current driving distance. Furthermore, processor 23 includes the date when the driving information was generated and the vehicle 2's identification information in the driving information. Then, whenever driving information is generated, processor 23 outputs the generated driving information to wireless communication terminal 13 via communication interface 21. Thus, the driving information is sent to server 3. Alternatively, driving information can also be generated by the ECU and sent to server 3 via wireless communication terminal 13.

[0043] Next, we will describe server 3 as an example of a data collection device for aboveground objects.

[0044] Figure 4 This is a hardware structure diagram of server 3, an example of a ground object data collection device. Server 3 has a communication interface 31, a storage device 32, a memory 33, and a processor 34. The communication interface 31, storage device 32, and memory 33 are connected to the processor 34 via signal lines. Server 3 may also have input devices such as a keyboard and mouse, and a display device such as an LCD screen.

[0045] Communication interface 31 is an example of a communication unit, having interface circuitry for connecting server 3 to communication network 4. Communication interface 31 is then configured to communicate with vehicle 2 via communication network 4 and wireless base station 5. Specifically, communication interface 31 delivers ground object data and driving information received from vehicle 2 via wireless base station 5 and communication network 4 to processor 34. Additionally, communication interface 31 sends collection instructions received from processor 34 to vehicle 2 via communication network 4 and wireless base station 5. Furthermore, communication interface 31 receives traffic volume information from traffic information server (not shown) via communication network 4 and delivers this traffic volume information to processor 34.

[0046] Storage device 32 is an example of a storage unit, such as having a hard disk drive or an optical recording medium and its access device. Storage device 32 stores various data and information used in map data collection and processing. For example, storage device 32 stores maps as update targets, traffic volume information, and identification information of each vehicle 2. Furthermore, storage device 32 also stores ground feature data and driving information received from each vehicle 2. Additionally, storage device 32 may also store a computer program for performing ground feature data collection and processing executed on processor 34.

[0047] Memory 33 is another example of a storage unit, such as a non-volatile semiconductor memory and a volatile semiconductor memory. Memory 33 then temporarily stores various data generated during the execution of surface data collection and processing.

[0048] Processor 34 is an example of a control unit, having one or more CPUs (Central Processing Units) and their peripheral circuitry. Processor 34 may also include other computational circuitry such as logic units or numerical processing units. Then, processor 34 performs data collection and processing of above-ground structures.

[0049] Figure 5 This is a functional block diagram of a processor 34 associated with the collection and processing of above-ground object data. The processor 34 includes a vehicle classification unit 41, a region classification unit 42, a transmission condition setting unit 43, a notification unit 44, and a map updating unit 45. These components of the processor 34 are, for example, functional modules implemented by a computer program that operates on the processor 34. Alternatively, these components of the processor 34 may also be dedicated arithmetic circuits provided on the processor 34.

[0050] The vehicle classification unit 41 classifies each vehicle 2 into any of a number of levels (hereinafter referred to as driving distance levels for ease of explanation) corresponding to the driving distance during the most recent specified period (e.g., 1 week or 1 month). For each vehicle 2, the vehicle classification unit 41 calculates the sum of the driving distances during each driving time in the most recent specified period by referring to the driving information stored in the storage device 32, and uses this sum as the driving distance during the specified period.

[0051] The vehicle classification unit 41 sets the boundaries of each driving distance class, for example, so that the number of vehicles 2 included in each driving distance class is equal. For example, when classifying each vehicle 2 into three driving distance classes, the vehicle classification unit 41 classifies each vehicle 2 into driving distance classes 1 to 3, starting from the one with the shortest driving distance, in turn, according to 1 / 3 of the total number of vehicles 2. Furthermore, the vehicle classification unit 41 may also set each driving distance class in a way that the number of vehicles 2 included in each driving distance class is different. For example, the vehicle classification unit 41 may also set each driving distance class in a way that minimizes the number of vehicles 2 included in the first driving distance class and maximizes the number of vehicles 2 included in the second or third driving distance class. Conversely, the vehicle classification unit 41 may also set each driving distance class in a way that minimizes the number of vehicles 2 included in the third driving distance class and maximizes the number of vehicles 2 included in the first or second driving distance class. Furthermore, the number of driving distance classes is not limited to three; it may be set to any number of two or more, such as four or five.

[0052] When classifying each vehicle 2 into an arbitrary driving distance class, the vehicle classification unit 41 calculates the average driving distance of each vehicle 2 belonging to that driving distance class for each driving distance class. Then, the vehicle classification unit 41 notifies the sending condition setting unit 43 of the driving distance class to which each vehicle 2 belongs. In addition, the vehicle classification unit 41 notifies the area classification unit 42 of the average driving distance for each driving distance class.

[0053] The regional classification section 42 classifies multiple areas presented in the map as the object of generation or updating, i.e., multiple areas as the objects of collection of aboveground property data, according to traffic volume. Furthermore, the multiple areas as the objects of collection of aboveground property data will sometimes be referred to simply as multiple areas or each area.

[0054] Multiple regions can be defined by dividing the overall area of ​​the map, which is the object of generation or updating, into a grid pattern at intervals of a specified length (e.g., tens to hundreds of meters). However, this is not limited to this example; regions can also be defined such that areas with higher road density have narrower areas. Alternatively, regions can be defined such that areas with higher density of specific road features (e.g., intersections, merging, or branching) have narrower areas. Or, each region can be defined such that it includes a road section or an intersection.

[0055] In this embodiment, the area classification unit 42 refers to traffic volume information received from the traffic information server or read from the storage device 32 via the communication network 4. The traffic volume information includes, for each of the multiple areas, the traffic volume for that area over a specified period (e.g., the most recent day, week, or month). The traffic volume for each area can be, for example, set as the average or maximum number of vehicles passing through one or more locations within that area.

[0056] The area classification unit 42 classifies each area into any of a number of levels (hereinafter referred to as traffic volume levels for ease of explanation) based on the traffic volume of that area. For example, the area classification unit 42 sets the same number of traffic volume levels as the number of travel distance levels. Furthermore, the area classification unit 42 sets each traffic volume level such that the ratio of the number of areas included in each traffic volume level, from the lowest to the highest in a predetermined order, to the total number of areas is equal to the ratio of the average distance of each travel distance level, from the shortest to the longest in a predetermined order, to the average travel distance of the travel distance level. For example, if the ratio of the average travel distance of each of the three travel distance levels is 1:3:10, the area classification unit 42 sets traffic volume level 1 such that the ratio of the number of areas included in traffic volume level 1 (the lowest traffic volume level) to the total number of areas is 1 / 10. Additionally, the area classification unit 42 sets traffic volume level 2 such that the ratio of the sum of the number of areas included in traffic volume level 1 (the lowest traffic volume level) and the number of areas included in traffic volume level 2 (the second lowest traffic volume level) to the total number of areas is 3 / 10. Then, the area classification unit 42 sets traffic volume level 3 such that the total number of areas included in traffic volume level 1, the number of areas included in traffic volume level 2, and the number of areas included in traffic volume level 3 (which has the highest traffic volume) equals the total number of areas. Then, the area classification unit 42 sequentially classifies each area into any level from traffic volume level 1 to traffic volume level 3, starting from areas with low traffic volume. In this way, each area is classified, making it easier to achieve a more balanced distribution of the amount of surface object data transmitted by each vehicle 2.

[0057] The area classification unit 42 can also classify each area into different levels according to a different ratio than described above. For example, the area classification unit 42 can also classify each area into any traffic volume level, starting from the area with the lowest traffic volume, in such a way that the number of areas included in each traffic volume level is equal. In addition, the area classification unit 42 can also set the traffic volume levels in a way that the number of traffic volume levels is different from the number of travel distance levels.

[0058] The Regional Classification Department 42 notifies the Sending Condition Setting Department 43 of the traffic volume level belonging to each region.

[0059] The transmission condition setting unit 43 sets the transmission conditions for each vehicle 2 in such a way that the shorter the travel distance of a vehicle 2 among the multiple vehicles 2, the more lenient the transmission conditions for ground object data are. In this embodiment, the transmission condition setting unit 43 sets the transmission conditions for each vehicle 2 in such a way that the shorter the travel distance of a vehicle 2, the larger the geographical area that allows the transmission of ground object data. That is, for each vehicle 2, the collection target area is set according to the travel distance of that vehicle 2.

[0060] For example, regarding the transmission condition setting unit 43, the shorter the average travel distance of the travel distance class to which the vehicle 2 of interest belongs, the more likely it is that the transmission of surface object data will be allowed even in areas belonging to traffic volume classes with higher traffic volume. As described above, each vehicle 2 is classified into three travel distance classes (travel distance class 1 to travel distance class 3) starting from the side with the shortest travel distance, and each area is classified into three traffic volume classes (traffic volume class 1 to traffic volume class 3) starting from the side with lower traffic volume. In this case, the transmission condition setting unit 43 allows the transmission of surface object data for all areas for each vehicle 2 belonging to travel distance class 1, which has the shortest travel distance. In addition, the transmission condition setting unit 43 allows the transmission of surface object data for each vehicle 2 belonging to travel distance class 2, which has the second shortest travel distance, for areas belonging to either of the two traffic volume classes (traffic volume class 1 and traffic volume class 2) starting from the side with lower traffic volume. Furthermore, the transmission condition setting unit 43 allows the transmission of ground object data only for areas belonging to traffic volume level 1, which has the lowest traffic volume, for each vehicle 2 belonging to the longest travel distance level 3. In this way, by setting the transmission conditions for ground object data for each vehicle 2, the transmission condition setting unit 43 can balance the amount of ground object data transmitted by each vehicle 2. In addition, for roads where it is difficult to collect ground object data due to low traffic volume, vehicles 2 with long travel distances are also allowed to transmit ground object data, so the transmission condition setting unit 43 can also prevent situations where it is even more difficult to collect ground object data on roads with low traffic volume.

[0061] Figure 6 This is a diagram illustrating an example of the relationship between traffic volume levels set for each area and the permitted travel distance levels for transmitting surface data. (Example) Figure 6As shown, the map, which is the object of generation or updating, presents multiple grid-like regions 600. Region 600a, represented by dots, is classified as Traffic Volume Level 3, the region with the highest traffic volume among the three traffic volume levels 1 to 3. Region 600b, represented by diagonal lines, is classified as Traffic Volume Level 2, the region with the second highest traffic volume among the three traffic volume levels 1 to 3. The other regions 600c are classified as Traffic Volume Level 1, the region with the lowest traffic volume. Therefore, for each vehicle 2 belonging to the longest travel distance level 3 among the three travel distance levels 1 to 3, the transmission of surface object data is only permitted for region 600c within each region 600. Furthermore, for each vehicle 2 belonging to the second longest travel distance level 2, the transmission of surface object data is permitted for regions 600b and 600c within each region 600. Then, for each vehicle 2 belonging to the shortest travel distance level 3, the transmission of surface object data is permitted for all regions of region 600.

[0062] Furthermore, if the number of travel distance levels differs from the number of traffic volume levels, a reference table indicating the traffic volume levels that allow the transmission of ground object data can be prepared in advance for each travel distance level and stored in the storage device 32. Then, the transmission condition setting unit 43 determines, by referring to this reference table, the traffic volume level that includes the area where the transmission of ground object data for vehicles 2 belonging to that travel distance level is permitted.

[0063] For each vehicle 2, the transmission condition setting unit 43 designates the area from which the transmission of above-ground object data for that vehicle 2 is permitted as the collection target area. Then, the transmission condition setting unit 43 notifies the notification unit 44 of the information indicating the designated collection target area for each vehicle 2.

[0064] The notification unit 44 generates a collection instruction for each vehicle 2, instructing the collection of surface object data under the transmission conditions set for that vehicle 2. In this embodiment, the transmission conditions specify a collection target area, so the notification unit 44 generates a collection instruction for each vehicle 2 that includes information determining the designated collection target area for that vehicle 2. The notification unit 44 may also include information indicating the type of surface object data to be collected in the collection instruction. In this case, information indicating the type of surface object data to be collected can be pre-input for each area via an input device (not shown) and stored in the storage device 32. Then, the notification unit 44 sends the collection instruction generated for that vehicle 2 to that vehicle 2 via the communication interface 31, referring to the vehicle 2's identification information.

[0065] In addition, the notification unit 44 can also send the generated or updated map to each vehicle 2 via the communication interface 31.

[0066] The map update unit 45 generates or updates the map read from the storage device 32 based on the collected ground object data. For example, if the ground object data is a whole image or a partial image, the map update unit 45 performs the same processing as the data acquisition device 14 mounted on the vehicle 2, detecting ground objects and their types from the whole image or partial image, and inferring the location of the detected ground objects. Then, for ground objects of the same type located within a specified range, the map update unit 45 determines the location of the ground object as the average of the location of the ground object contained in the collected ground object data or the location of the ground object inferred as described above. Then, for each ground object whose location has been determined, the map update unit 45 includes information indicating the type of ground object and the determined location in the map, thereby generating or updating the map.

[0067] Figure 7 This is a flowchart of the action for collecting and processing surface data in server 3. The processor 34 of server 3 performs surface data collection and processing according to the flowchart shown below at predetermined intervals.

[0068] The vehicle classification unit 41 of the processor 34 classifies each vehicle 2 into any of a plurality of distance levels based on the distance traveled by the vehicle 2 in the most recent specified period (step S101). In addition, the area classification unit 42 of the processor 34 classifies multiple areas that are the objects of the collection of ground object data into any of a plurality of traffic volume levels based on the traffic volume of the area (step S102).

[0069] Regarding the transmission condition setting unit 43 of processor 23, the transmission conditions for ground object data are set for each vehicle 2 in a manner that the shorter the average travel distance of the travel distance class to which the vehicle of interest 2 belongs, the more likely it is that the transmission of ground object data is allowed even in areas belonging to traffic volume classes with higher traffic volume (step S103). Then, according to the set transmission conditions, the transmission condition setting unit 43 designates the areas in multiple regions where the transmission of ground object data for that vehicle 2 is allowed as the collection target area for each vehicle 2 (step S104).

[0070] Then, the notification unit 44 of the processor 34 generates a collection instruction for each vehicle 2, which includes information on identifying the designated collection target area, and sends the collection instruction to the vehicle 2 via the communication interface 31 (step S105). After that, the processor 34 ends the aboveground object data collection process.

[0071] As explained above, this ground object data collection device sets transmission conditions for each vehicle in a way that eases the transmission conditions for ground object data transmission among multiple vehicles capable of generating and transmitting ground object data within the most recent specified period. Then, the ground object data collection device notifies each vehicle via its communication unit of a collection instruction to collect ground object data under the set transmission conditions. Therefore, this ground object data collection device can evenly distribute the amount of ground object data transmitted by each vehicle. In particular, the ground object data collection device classifies multiple areas that are the targets of ground object data collection according to traffic volume, and allows ground object data transmission even in areas with higher traffic volume for vehicles with shorter travel distances. Therefore, the ground object data collection device allows ground object data transmission in areas with low traffic volume for vehicles with longer travel distances, thus preventing ground object data collection from becoming even more difficult on roads where it is difficult to collect data due to low traffic volume. Furthermore, the ground object data collection device generates collection instructions for each vehicle based on the traffic volume in each area and the travel distance of each vehicle, so it is not necessary to manage the number of ground object data received for each vehicle. As a result, the load on the ground object data collection device is reduced.

[0072] According to a variation, the processor 34 of server 3 may also, whenever it receives ground object data, associate the received ground object data with the identification information of the vehicle 2 that sent the ground object data and the date and time of receipt, and store it in storage device 32. Additionally, vehicle classification unit 41 may count the amount of ground object data sent by each vehicle 2 within the most recent specified period. Then, vehicle classification unit 41 classifies each vehicle 2 into any of a plurality of levels (hereinafter, for ease of explanation, referred to as data volume levels) corresponding to the amount of ground object data sent within the most recent specified period. For example, vehicle classification unit 41 sets the boundaries of each data volume level in such a way that the number of vehicles 2 included in each data volume level is equal. For example, when classifying each vehicle 2 into three data volume levels, vehicle classification unit 41 classifies each vehicle 2 into data volume levels 1 to 3, sequentially according to 1 / 3 of the total number of vehicles 2, starting from the level with the smallest amount of ground object data sent.

[0073] In this modified example, the transmission condition setting unit 43 sets the transmission condition for each vehicle 2 in such a way that the vehicle 2 that has transmitted less ground object data in the most recent specified period among the multiple vehicles 2 makes the transmission condition for ground object data more lenient. For example, the lower the average amount of ground object data transmitted by each vehicle (hereinafter referred to as average transmission amount) with respect to the data volume level to which the vehicle 2 of interest belongs, the more likely the transmission of ground object data is allowed even in areas belonging to the traffic volume level with higher traffic volume.

[0074] According to this variation, the ground object data collection device eases the transmission conditions for vehicles transmitting less ground object data, thus equalizing the amount of ground object data transmitted by each vehicle. Furthermore, in this variation, the ground object data collection device also allows the transmission of ground object data in areas with low traffic volume for vehicles transmitting a large amount of ground object data, thus preventing difficulties in collecting ground object data on roads with low traffic volume.

[0075] According to other variations, the area to be collected can be set for each vehicle 2 based on the amount of ground object data received from each area that is the object of the ground object data collection.

[0076] In this case, a target collection volume of ground cover data is set for each region. Furthermore, the target collection volume can be set to the same value for all regions, or it can be set to a different value for each region. Then, for each region, the region classification unit 42 counts the amount of ground cover data received in the most recent specified period, and calculates the amount of ground cover data received for the target collection volume for each region as the sufficiency rate. The region classification unit 42 classifies each region into any of a number of levels (hereinafter, for ease of explanation, referred to as sufficiency rate levels) based on the sufficiency rate of that region. For example, the region classification unit 42 sets a sufficiency rate level with the same number of driving distance levels or the same number of data volume levels. Alternatively, the region classification unit 42 may set a sufficiency rate level in a way that the number of sufficiency rate levels is different from the number of driving distance levels or the number of data volume levels. Then, the region classification unit 42 classifies each region into any sufficiency rate level, starting from the region with the lower sufficiency rate, in a way that the number of regions included in each sufficiency rate level is equal. In addition, the regional classification section 42 can also classify each region into any sufficiency level in such a way that the number of regions included in each sufficiency level is different, starting from the side with the lower sufficiency.

[0077] In this case, the transmission condition setting unit 43 sets transmission conditions such that the shorter the travel distance of vehicle 2 or the less data of ground objects being transmitted, the more likely it is to transmit ground object data in areas with higher sufficiency rates. For example, regarding the transmission condition setting unit 43, the shorter the average travel distance of the travel distance class to which the vehicle 2 of interest belongs, the more likely it is to transmit ground object data in areas with higher sufficiency rates. Alternatively, regarding the transmission condition setting unit 43, the lower the average transmission amount of the data volume class to which the vehicle 2 of interest belongs, the more likely it is to transmit ground object data in areas with higher sufficiency rates.

[0078] According to this variation, the more a vehicle 2 travels a shorter distance or transmits less ground object data, the more likely it is to transmit ground object data in areas with higher sufficiency. That is, it is easier to transmit ground object data in areas with lower sufficiency. Therefore, this ground object data collection device can even out the amount of ground object data transmitted from each vehicle and prevent ground object data from being difficult to collect in areas with low sufficiency, i.e., areas where it is difficult to collect the required amount of ground object data.

[0079] Furthermore, according to other variations, the transmission condition setting unit 43 can also set transmission conditions for each vehicle 2 in such a way that the longer the travel distance of a vehicle 2, the more restricted the time period during which ground object data can be transmitted. Similarly, the transmission condition setting unit 43 can also set transmission conditions for each vehicle 2 in such a way that the more ground object data transmitted in the most recent specified period, the more restricted the time period during which ground object data can be transmitted. For example, regarding the transmission condition setting unit 43, the longer the average travel distance of the travel distance class to which the vehicle 2 of interest belongs, the shorter the time period during which ground object data can be transmitted. In particular, the time period during which ground object data can be transmitted is preferably set to a period of time in a day when the communication network 4 has relatively low traffic.

[0080] In this modified example, the ground object data collection device can also balance the amount of ground object data transmitted by each vehicle. Furthermore, in this modified example, the transmission conditions are set to be independent of each area, so the processing of the area classification unit 42 can be omitted. Therefore, the processing load of the ground object data collection device is reduced.

[0081] Furthermore, according to other variations, the transmission condition setting unit 43 can also set transmission conditions for each vehicle 2 in such a way that the longer the travel distance of a vehicle 2, the fewer types of ground object data can be transmitted. Similarly, the transmission condition setting unit 43 can also set transmission conditions for each vehicle 2 in such a way that the more ground object data a vehicle 2 has transmitted in the most recent specified period, the fewer types of ground object data can be transmitted. In this case, for each area or road category (e.g., ordinary road or dedicated vehicle lane) or each road structure (straight road, intersection, merging, branching, etc.), the types of ground object data to be collected are specified and notified to each vehicle 2 in advance. Then, for example, if the travel distance of the vehicle 2 of interest to the transmission condition setting unit 43 in the most recent specified period is more than a specified distance, the types of ground object data that can be transmitted for that vehicle 2 are limited to data representing the types of ground objects. On the other hand, if the transmission condition setting unit 43 transmits data for the vehicle 2 it is interested in during the most recent specified period, and the distance traveled is less than a specified distance, then for that vehicle 2, it can transmit not only data indicating the type of ground objects, but also partial and overall images. Alternatively, if the amount of ground object data transmitted by the transmission condition setting unit 43 from the vehicle 2 it is interested in during the most recent specified period is more than a specified amount, then for that vehicle 2, the types of ground object data that can be transmitted are limited to data indicating the type of ground objects. On the other hand, if the amount of ground object data transmitted by the transmission condition setting unit 43 from the vehicle 2 it is interested in during the most recent specified period is less than a specified amount, then for that vehicle 2, it can transmit not only data indicating the type of ground objects, but also partial and overall images.

[0082] In this modified example, the ground object data collection device can also equalize the amount of ground object data transmitted by each vehicle. Furthermore, according to this modified example, the ground object data collection device can set transmission conditions for the types of ground object data that are particularly desired to be collected, in a manner that allows each vehicle to transmit ground object data, thus preventing the collection of such types of ground object data from being suppressed.

[0083] Furthermore, the computer program that enables the computer to perform the functions of the processor in the above-described embodiments or variations of the above-described ground cover data collection device can also be provided in the form of a recording medium that can be read by a computer. In addition, the recording medium that can be read by a computer can be, for example, a magnetic recording medium, an optical recording medium, or a semiconductor memory.

[0084] As described above, those skilled in the art can make various modifications within the scope of this invention, matching the manner of implementation.

Claims

1. A data collection device for aboveground objects, comprising: The storage unit stores, for each of the multiple vehicles, the amount of ground object data sent by the vehicle that represents ground objects associated with the vehicle's travel or the travel distance of the vehicle. The transmission condition setting unit determines the driving distance of the vehicle during the period of collecting the ground object data and the amount of ground object data transmitted by the vehicle during the period of collecting the ground object data. It sets transmission conditions for each of the plurality of vehicles so that, among the plurality of vehicles, the shorter the driving distance or the less ground object data transmitted, the more relaxed the transmission conditions for transmitting the ground object data are, and the larger the geographical range for transmitting the ground object data is allowed. In order to balance the transmission volume of each vehicle by allowing vehicles with short driving distances or less ground object data to transmit ground object data in areas with high traffic volume, and allowing vehicles with long driving distances or more ground object data transmitted to transmit ground object data in areas with low traffic volume. as well as The notification unit, via the communication unit, notifies each of the plurality of vehicles of a collection instruction to collect the above-ground object data under the transmission conditions set for that vehicle.

2. The aboveground object data collection device according to claim 1, wherein, It also has: The vehicle classification department classifies the plurality of vehicles into any of a plurality of driving distance classes based on the driving distance of each vehicle. as well as The regional classification department classifies the multiple regions into any of a plurality of traffic volume levels based on the traffic volume of each region. The transmission condition setting unit sets the transmission conditions in such a way that the shorter the average driving distance of each of the plurality of vehicles in the driving distance class to which the vehicle belongs in the plurality of driving distance classes, the more likely the area belonging to the traffic volume class with more traffic volume in the plurality of traffic volume classes is to allow the transmission of the above-ground object data.

3. The above-ground object data collection device according to claim 1, wherein, The storage unit also stores, for each of the multiple areas that are the objects of the collection of the above-ground object data, the amount of above-ground object data received from any of the multiple vehicles during a specified period, and the target collection amount of the above-ground object data. The transmission condition setting unit sets the transmission conditions in such a way that the transmission of ground object data is allowed for vehicles with shorter travel distances or vehicles with smaller amounts of ground object data transmitted, and for areas where the ratio of the amount of ground object data received to the target collection amount is higher.

4. A method for collecting data on aboveground features, comprising: The distance traveled by a vehicle during the period of collecting ground object data representing ground objects associated with the vehicle's travel and the amount of ground object data transmitted by the vehicle during the period of collecting the ground object data are determined. Transmission conditions are set for each of a plurality of vehicles such that, among the plurality of vehicles, the shorter the travel distance or the less ground object data transmitted, the more lenient the transmission conditions for transmitting ground object data are, and the larger the geographical area for allowing the transmission of ground object data is. This is to balance the transmission volume of each vehicle by allowing vehicles among the plurality of vehicles with shorter travel distances or less ground object data transmitted to transmit ground object data in areas with high traffic volume, and allowing vehicles among the plurality of vehicles with longer travel distances or more ground object data transmitted to transmit ground object data in areas with low traffic volume. For each of the plurality of vehicles, a collection instruction is notified to that vehicle via the communication unit, instructing it to collect the above-ground object data under the transmission conditions set for that vehicle.

5. A computer program product for collecting data on aboveground features, used to cause a computer to execute: The distance traveled by a vehicle during the period of collecting ground object data representing ground objects associated with the vehicle's travel and the amount of ground object data transmitted by the vehicle during the period of collecting the ground object data are determined. Transmission conditions are set for each of a plurality of vehicles such that, among the plurality of vehicles, the shorter the travel distance or the less ground object data transmitted, the more lenient the transmission conditions for transmitting ground object data are, and the larger the geographical area for allowing the transmission of ground object data is. This is to balance the transmission volume of each vehicle by allowing vehicles among the plurality of vehicles with shorter travel distances or less ground object data transmitted to transmit ground object data in areas with high traffic volume, and allowing vehicles among the plurality of vehicles with longer travel distances or more ground object data transmitted to transmit ground object data in areas with low traffic volume. For each of the plurality of vehicles, a collection instruction is notified to that vehicle via the communication unit, instructing it to collect the above-ground object data under the transmission conditions set for that vehicle.

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