Data collection device, data collection method, computer program for data collection, and data collection system

Abstract

To provide a data acquisition device that can transmit a series of data representing a feature acquired over a certain number of continuous sections to another appliance without any loss.SOLUTION: A data acquisition device comprises: an image storing unit 41 that stores an image in a storage unit 32, which represents the surrounding of a vehicle 2, and is generated by a camera 21 mounted on the vehicle 2 while the vehicle 2 is traveling; a detection unit 42 that generates probe data representing a predetermined feature present around the vehicle 2 detected from the image and stores the generated probe data in the storage unit 32; a communication band setting unit 43 that sets a communication band for a probe data according to a data amount of a series of probe data stored in the storage unit 32; and a communication processing unit 44 that transmits the series of probe data to a server 4 via a communication device 23 in priority to the series of images stored in the storage unit 32 by using the communication band for a probe.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a data collection device, a data collection method, a computer program for data collection, and a data collection system that collect data used to generate or update a map. [Background technology]

[0002] A highly accurate map that an automatic driving system of a vehicle refers to in order to control the automatic driving of the vehicle is required to accurately represent information about roads. Therefore, data representing roads or features around the roads in a specific area, obtained by a sensor mounted on the vehicle, is collected from the vehicle that has actually driven in the specific area. However, the communication capacity of the communication line between the vehicle and the server is limited. Therefore, in some cases, the capacity of the storage device that temporarily stores the data on the vehicle side is insufficient, and the data is erased from the storage device before being transmitted to the server. Therefore, a technology has been proposed for uploading sensor information from an on-board sensor to an external device in an appropriate order in the collection of data detected in the vehicle according to changes in the line speed of the communication line between the on-board device and the external device (see Patent Document 1).

[0003] In the technology disclosed in Patent Document 1, the in-vehicle device determines which of the analysis result of the sensor information or the sensor information to transmit with priority based on the line speed information of the communication line. Then, the in-vehicle device transmits either the analysis result or the sensor information with priority according to the determination result. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-176311 A Summary of the Invention [Problem to be solved by the invention]

[0005] If data transmission is interrupted midway through a road section for which data representing features is to be collected, there is a risk that the data collected on the server side will be insufficient.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a data collection device capable of transmitting a series of data representing features obtained over a relatively continuous section to another device without loss. [Means for solving the problem]

[0007] According to one embodiment, there is provided a data collection device, which includes an image storage unit configured to store in a storage unit an image showing the surroundings of the vehicle generated by a camera mounted on the vehicle while the vehicle is traveling, a detection unit configured to detect a predetermined feature from the image, generate probe data showing the detected feature, and store the generated probe data in the storage unit, a communication band setting unit configured to set a probe communication band occupying a communication band of a communication line between the communication device mounted on the vehicle and a server according to an amount of the series of probe data stored in the storage unit so that all of the series of probe data can be transmitted to the server via the communication device mounted on the vehicle, and a communication processing unit configured to transmit the series of probe data to the server via the communication device in priority to the series of images stored in the storage unit by using the probe communication band, and to transmit the series of images to the server via the communication device by using the remaining communication band of the communication line other than the probe communication band.

[0008] In addition, in this data collection device, after transmitting a series of probe data generated over a section of a predetermined distance or more that passes through the collection target area to the server, if an image that was generated when the vehicle traveled through the collection target area and that has not been transmitted is stored in the memory unit, it is preferable that the communication processing unit transmits the untransmitted image to the server via the communication device in priority over other probe data stored in the memory unit.

[0009] In the data collection device, it is preferable that the communication band setting unit widens the probe communication band as the amount of the series of probe data stored in the storage unit increases.

[0010] Furthermore, when the ratio of the data volume of a series of probe data to the memory area in the memory unit for storing probe data becomes equal to or greater than a predetermined threshold value, it is preferable that the communication bandwidth setting unit sets the communication bandwidth for the probe so that the data volume of the probe data that can be transmitted to the server per unit time is greater than the data volume of the probe data stored in the memory area per unit time in the most recent specified period.

[0011] According to another aspect of the present invention, there is provided a data collection method, which includes: storing in a storage unit an image showing the surroundings of the vehicle generated by a camera mounted on the vehicle while the vehicle is traveling, detecting a predetermined feature from the image, generating probe data showing the detected feature, storing the generated probe data in the storage unit, setting a probe communication band occupying a communication band of a communication line between the communication device mounted on the vehicle and a server according to an amount of the series of probe data stored in the storage unit so that all of the series of probe data can be transmitted to the server via the communication device mounted on the vehicle, transmitting the series of probe data to the server via the communication device in priority to the series of images stored in the storage unit by using the probe communication band, and transmitting the series of images to the server via the communication device by using the remaining communication band of the communication line other than the probe communication band.

[0012] According to yet another aspect of the present invention, there is provided a computer program for collecting data, the computer program for collecting data including instructions for causing a processor mounted on the vehicle to execute the following operations: storing in a storage unit an image showing the surroundings of the vehicle generated by a camera mounted on the vehicle while the vehicle is traveling, detecting a predetermined feature from the image, generating probe data showing the detected feature, storing the generated probe data in the storage unit, setting a probe communication band occupying a communication band of a communication line between the communication device and the server according to an amount of the series of probe data stored in the storage unit so that all of the series of probe data can be transmitted to the server via the communication device mounted on the vehicle, transmitting the series of probe data to the server via the communication device in priority to the series of images stored in the storage unit by using the probe communication band, and transmitting the series of images to the server via the communication device by using the remaining communication band of the communication line other than the probe communication band.

[0013] According to yet another aspect of the present invention, there is provided a data collection system including a data collection device mounted on a vehicle and a server communicatively connected to the data collection device, wherein the data collection system includes a storage unit, a detection unit configured to store in the storage unit an image showing the surroundings of the vehicle generated by a camera mounted on the vehicle while the vehicle is traveling, detect a predetermined feature from the image, generate probe data showing the detected feature, and store the generated probe data in the storage unit, a communication band setting unit configured to set a probe communication band occupying a communication band of a communication line between the communication device and the server according to an amount of the series of probe data stored in the storage unit so that all of the series of probe data can be transmitted to the server via the communication device mounted on the vehicle, and a communication processing unit configured to transmit the series of probe data to the server via the communication device in priority to the series of images stored in the storage unit by using the probe communication band, and to transmit the series of images to the server via the communication device by using the remaining communication band of the communication line other than the probe communication band. Effect of the Invention

[0014] The data collection device according to the present disclosure has the advantage of being able to transmit a series of data representing features obtained over a fairly continuous section to another device without any loss. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a data collection system in which a data collection device is implemented; [Diagram 2] FIG. 1 is a schematic configuration diagram of a vehicle. [Diagram 3] FIG. 2 is a hardware configuration diagram of a data collection device according to one embodiment. [Figure 4] FIG. 2 is a functional block diagram of a processor of the data collection device. [Diagram 5] 13A and 13B are diagrams showing an example of the amount of untransmitted probe data and the amount of collection target data uploaded to the server per frame, respectively. [Figure 6] 11 is an operational flowchart of a process related to generation of probe data and storage of the probe data and images, among the data collection processes. [Figure 7] 13 is an operational flowchart of a process related to uploading of collection target data, part of the data collection process. [Figure 8] FIG. 2 is a diagram illustrating a hardware configuration of a server. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, a data collection device, a data collection method executed by the data collection device, a computer program for data collection, and a data collection system will be described with reference to the drawings. The data collection device is mounted on a vehicle. The data collection device generates data (hereinafter referred to as probe data) representing specific features on or around a road, which is used for generating or updating a map, based on an image representing the surroundings of the vehicle. The data collection device transmits the probe data generated while the vehicle is traveling in a collection target area to a server via a communication device. At that time, the data collection device sets a communication band used for transmitting the probe data, which occupies a communication band of a communication line between the communication device and the server. The data collection device transmits a series of probe data generated in the collection target area and stored in the memory to the server using the set communication band, with priority over other collection target data stored in the memory. Furthermore, the data collection device transmits other collection target data, such as images, to the server using the remaining communication band of the communication line that can be used for transmitting the collection target data.

[0017] FIG. 1 is a schematic diagram of a data collection system in which a data collection device is implemented. In this embodiment, the data collection system 1 includes a data collection device 3 mounted on at least one vehicle 2, and a server 4. The data collection device 3 is connected to the server 4 via the wireless base station 6 and the communication network 5 by, for example, accessing a wireless base station 6 connected to a communication network 5 to which the server 4 is connected via a gateway (not shown). Note that, although only one vehicle 2 is illustrated in FIG. 1, the data collection system 1 may include a plurality of vehicles 2 mounted with the data collection device 3. Similarly, a plurality of wireless base stations 6 may be connected to the communication network 5.

[0018] First, a description will be given of the vehicle 2 and the data collection device 3. As described above, the data collection system 1 may include a plurality of vehicles 2 equipped with data collection devices 3, but since each vehicle 2 and each data collection device 3 has the same configuration and executes the same process with respect to data collection processing, the following description will be given of one vehicle 2 and one data collection device 3.

[0019] 2 is a schematic diagram of the vehicle 2. The vehicle 2 has a camera 21 for capturing images of the surroundings of the vehicle 2, a GPS receiver 22, a wireless communication terminal 23, and a data collection device 3. The camera 21, the GPS receiver 22, the wireless communication terminal 23, and the data collection device 3 are communicatively connected via an in-vehicle network conforming to a standard such as a controller area network. The vehicle 2 may further have a distance measurement sensor (not shown) such as a LiDAR sensor for measuring distances to objects around the vehicle 2.

[0020] The camera 21 is an example of an imaging unit, and has a two-dimensional detector configured with an array of photoelectric conversion elements sensitive to visible light, such as a CCD or C-MOS, and an imaging optical system that forms an image of the area to be photographed on the two-dimensional detector. The camera 21 is attached, for example, inside the vehicle cabin of the vehicle 2 so as to face the front of the vehicle 2. The camera 21 photographs the area in front of the vehicle 2 at a predetermined photographing period (for example, 1 / 30 to 1 / 10 seconds) and generates an image showing the area in front of the vehicle 2. The image obtained by the camera 21 may be a color image or a gray image. Note that the vehicle 2 may be provided with a plurality of cameras 21 with different photographing directions or focal lengths.

[0021] Every time the camera 21 generates an image, it outputs the generated image to the data collection device 3 via the in-vehicle network.

[0022] The GPS receiver 22 receives GPS signals from GPS satellites at predetermined intervals and determines the own position of the vehicle 2 based on the received GPS signals. Then, the GPS receiver 22 outputs positioning information representing the positioning result of the own position of the vehicle 2 based on the GPS signals to the data collection device 3 via the in-vehicle network at predetermined intervals. Note that the vehicle 2 may have a receiver that complies with a satellite positioning system other than the GPS receiver 22. In this case, it is sufficient that the receiver determines the own position of the vehicle 2.

[0023] The wireless communication terminal 23 is an example of a communication device, and is a device that executes wireless communication processing conforming to a predetermined wireless communication standard. For example, the wireless communication terminal 23 accesses the wireless base station 6, and is connected to the server 4 via the wireless base station 6 and the communication network 5. That is, a communication line is established between the wireless communication terminal 23 and the server 4 via the wireless base station 6 and the communication network 5. Then, the wireless communication terminal 23 receives a downlink wireless signal including a collection instruction signal or a signal indicating a collection target area received from the server 4, and outputs the received signal to the data collection device 3. Also, the wireless communication terminal 23 generates an uplink wireless signal including a specified type of collection target data (for example, probe data or image) received from the data collection device 3. Then, the wireless communication terminal 23 transmits the uplink wireless signal to the wireless base station 6, thereby transmitting the collection target data to the server 4. Furthermore, the wireless communication terminal 23 notifies the data collection device 3 of information indicating a communication band that the data collection device 3 can use to transmit collection target data between the wireless base station 6 and the wireless communication terminal 23 every time a connection with the wireless base station 6 is established, or every time a change occurs in the communication band available between the wireless base station 6 and the wireless communication terminal 23. The communication band available for transmitting the collection target data between the wireless base station 6 and the wireless communication terminal 23 is substantially the same as the communication band available for transmitting the collection target data between the server 4 and the wireless communication terminal 23 .

[0024] 3 is a hardware configuration diagram of the data collection device 3. The data collection device 3 temporarily stores images received from the camera 21. Furthermore, the data collection device 3 generates probe data based on the images and the like, and temporarily stores the generated probe data. Then, the data collection device 3 transmits the probe data and images to the server 4 via the wireless communication terminal 23. To this end, the data collection device 3 has a communication interface 31, a memory 32, and a processor 33.

[0025] The communication interface 31 is an example of an in-vehicle communication unit, and has an interface circuit for connecting the data collection device 3 to an in-vehicle network. That is, the communication interface 31 is connected to the camera 21, the GPS receiver 22, and the wireless communication terminal 23 via the in-vehicle network. Then, the communication interface 31 passes the received image to the processor 33 every time it receives an image from the camera 21. Also, the communication interface 31 passes the received positioning information to the processor 33 every time it receives positioning information from the GPS receiver 22. Furthermore, the communication interface 31 passes the information to the processor 33 every time it receives information from the server 4, such as a collection instruction signal, from the wireless communication terminal 23. Furthermore, when the communication interface 31 receives information indicating a communication band available for wireless communication between the wireless communication terminal 23 and the wireless base station 6 from the wireless communication terminal 23, it passes the information to the processor 33. Furthermore, the communication interface 31 outputs the collection target data and the like received from the processor 33 to the wireless communication terminal 23 via the in-vehicle network.

[0026] The memory 32 is an example of a storage unit, and includes, for example, a volatile semiconductor memory and a non-volatile semiconductor memory. The memory 32 may further include another storage device such as a hard disk device. The memory 32 stores various data used in processing related to data collection executed by the processor 33 of the data collection device 3. For example, the memory 32 stores identification information of the vehicle 2, parameters of the camera 21 such as the focal length, shooting direction, and installation position of the camera 21, various parameters for identifying a discriminator for detecting features from an image received from the camera 21, and positioning information received from the GPS receiver 22. Furthermore, the memory 32 stores information representing a collection target area received from the server 4. Furthermore, the memory 32 may store computer programs for implementing each processing executed by the processor 33. Furthermore, the memory 32 stores communication band information representing a communication band available to the data collection device 3 in a communication line between the wireless communication terminal 23 and the server 4.

[0027] Furthermore, the memory 32 is provided with a storage area for storing images (hereinafter referred to as the image storage area) and a storage area for storing probe data (hereinafter referred to as the probe storage area). The ratio of the size of the image storage area to the size of the probe storage area is preferably set so that both the image and the probe data generated for the same road section can be stored. For this purpose, the ratio of the size of the image storage area to the size of the probe storage area is set according to the data size of the image, the acquisition period of the image from the camera 21, the data size of the probe data, and the generation frequency of the probe data. For example, it is assumed that the ratio of the data size of the image obtained per unit time to the data size of the probe data is 100:1, and the ratio of the image acquisition frequency to the generation frequency of the probe data is 1:10. In this case, the ratio of the size of the image storage area to the size of the probe storage area is set to 10:1. The image received by the data collecting device 3 from the camera 21 is temporarily stored in the image storage area. Furthermore, the probe data generated by the processor 33 is temporarily stored in the probe storage area.

[0028] The processor 33 has one or more central processing units (CPUs) and their peripheral circuits. The processor 33 may further have other arithmetic circuits such as a logic arithmetic unit, a numerical arithmetic unit, or a graphic processing unit. The processor 33 executes data collection processing while the vehicle 2 is traveling.

[0029] 4 is a functional block diagram of the processor 33 of the data collection device 3. The processor 33 has an image storage unit 41, a detection unit 42, a communication band setting unit 43, and a communication processing unit 44. Each of these units in the processor 33 is, for example, a functional module realized by a computer program running on the processor 33. Alternatively, each of these units in the processor 33 may be a dedicated arithmetic circuit provided in the processor 33.

[0030] The image storage unit 41 writes the image into the image storage area of ​​the memory 32 every time the data collection device 3 receives an image from the camera 21. At that time, every time the image storage unit 41 receives an image from the camera 21, it associates the position of the vehicle 2 represented by the latest positioning information and the orientation of the vehicle 2 indicated by an orientation sensor (not shown) with the image. Furthermore, the image storage unit 41 may also associate parameters of the camera 21, such as the focal length, installation position, and shooting direction of the camera 21, with the image. When the image is uploaded to the server 4, the information associated with the image is uploaded to the server 4 together with the image itself. When the image storage area becomes full, the image storage unit 41 overwrites the images stored in the image storage area with the new image to be saved, starting from the oldest image.

[0031] The detection unit 42 detects a predetermined feature from the latest image generated by the camera 21 at predetermined intervals while the vehicle 2 is traveling, or each time the vehicle 2 travels a predetermined distance. The predetermined feature is a feature shown on a map to be generated or updated, such as various road markings, various road signs, curbs, guard rails, traffic lights, or poles for installing road signs. The detection unit 42 then generates probe data indicating the type of feature detected on the image and the position of the feature.

[0032] For example, the detection unit 42 detects a predetermined feature shown in the input image by inputting the image to a classifier. The detection unit 42 may use a deep neural network (DNN) having a convolutional neural network (CNN) type architecture, such as Single Shot MultiBox Detector or Faster R-CNN, as such a classifier. Alternatively, the detection unit 42 may use a DNN having a self attention network (SAN) type architecture, such as Vision Transformer, as such a classifier. Alternatively, the detection unit 42 may use a classifier based on another machine learning method, such as an AdaBoost classifier, as such a classifier. Such a classifier is trained in advance according to a predetermined learning method, such as backpropagation, using a large number of teacher images in which the predetermined feature is shown, so as to detect the predetermined feature to be detected from the image. The classifier then outputs information representing an area in which the feature to be detected is included on the input image (for example, a circumscribing rectangle of the feature to be detected, hereinafter referred to as an object area) and information representing the type of feature shown in the object area.

[0033] The detection unit 42 estimates the position of the feature shown in the object region detected from the image based on parameters such as the direction from the camera 21, the position of the vehicle 2 at the time of image generation, the traveling direction, the shooting direction of the camera 21, the focal length, and the installation position, which correspond to the center of gravity of the object region. The detection unit 42 then generates probe data including information representing the type of the detected feature and the estimated position. The detection unit 42 may further include information representing the position and traveling direction of the vehicle 2 at the time of image generation in the probe data. The detection unit 42 may further include information representing the size of the object region and its position on the image in the probe data. The detection unit 42 generates one probe data for each detected feature. Therefore, when multiple features are detected from one image, multiple probe data are generated from one image.

[0034] Every time the detection unit 42 generates probe data, it writes the generated probe data into the probe storage area of ​​the memory 32. When the probe storage area becomes full, the detection unit 42 overwrites the probe data stored in the probe storage area with the newly stored probe data, starting from the oldest probe data.

[0035] The communication band setting unit 43 sets the communication band to be used for transmitting the probe data among the communication bands available for the data collection device 3 to transmit the data to be collected in the communication line between the wireless communication terminal 23 and the server 4, depending on the amount of untransmitted series of probe data stored in the probe storage area. At that time, the communication band setting unit 43 sets the communication band preferentially, regardless of the size of the entire communication band available for transmitting the data to be collected, so that all of the series of untransmitted probe data can be transmitted to the server 4 via the wireless communication terminal 23. Hereinafter, the communication band used for transmitting the probe data will be referred to as the probe communication band.

[0036] For example, the communication band setting unit 43 sets the probe communication band when the vehicle 2 enters the collection target area or when wireless communication between the wireless communication terminal 23 and the wireless base station 6 becomes possible. The communication band setting unit 43 may also reset the probe communication band when the communication bandwidth between the wireless communication terminal 23 and the wireless base station 6 fluctuates by a predetermined amount or more. Alternatively, the communication band setting unit 43 may reset the probe communication band when the ratio of the data amount of the series of untransmitted probe data occupying the probe storage area (hereinafter referred to as the untransmitted data occupancy rate) exceeds a predetermined threshold value (for example, 0.5 to 0.8).

[0037] When the probe communication band is set at the timing when the vehicle 2 enters the collection target area, the communication band setting unit 43 refers to the information representing the collection target area stored in the memory 32 and the latest positioning information to determine whether the vehicle 2 has entered the collection target area. The collection target area is specified, for example, for one or more continuous road sections or for each area having a predetermined shape. When the collection target area is specified as a road section, the information representing the collection target area includes identification information for identifying the road section and information representing the positions of the ends at which the road section can be entered or exited. When the collection target area is an area having a predetermined shape, the information representing the collection target area includes information representing the positions of the outer edges of the area. When the position of the vehicle 2 represented by the latest positioning information is included in the area or road section indicated by the information representing the collection target area, the communication band setting unit 43 determines that the vehicle 2 has entered the collection target area.

[0038] The communication band setting unit 43 calculates the number of probe data generated per unit time by dividing the number of probe data generated in the most recent predetermined period by the length of the predetermined period. The communication band setting unit 43 then calculates the amount of probe data stored in the memory 32 per unit time by multiplying the number of probe data generated per unit time by the amount of data per one piece of probe data. Furthermore, the communication band setting unit 43 sets the probe communication band so as to be a band equivalent to the transmission speed of the amount of data per unit time obtained by multiplying the amount of probe data stored in the memory 32 per unit time by a predetermined coefficient according to the amount of data of a series of untransmitted probe data. Note that the greater the amount of untransmitted probe data, the greater the predetermined coefficient is preferably set to. As a result, the greater the amount of data of the series of probe data stored in the memory 32, the wider the probe communication band becomes. In addition, the predetermined coefficient is set to a value greater than 1 (for example, 1.2 to 2) when the untransmitted data occupancy rate is equal to or greater than a predetermined threshold. Therefore, when the amount of untransmitted probe data increases, the transmission speed of the probe data becomes faster than the writing speed of the probe data. That is, the amount of probe data that can be transmitted to the server 4 per unit time is greater than the amount of probe data stored in the probe storage area per unit time. Therefore, it becomes possible to transmit all of the series of untransmitted probe data to the server 4. Furthermore, even if the amount of untransmitted probe data increases while wireless communication between the wireless communication terminal 23 and the wireless base station 6 is temporarily impossible, the data collection device 3 can reduce the untransmitted data occupancy rate after wireless communication is resumed.

[0039] Alternatively, the communication band setting unit 43 may set the probe communication band corresponding to the untransmitted data occupancy rate by referring to a communication band table that indicates the relationship between the untransmitted data occupancy rate and the probe communication band. Even in this case, the probe communication band is set in the communication band table so that the transmission speed of the probe data is faster than the writing speed of the probe data when the untransmitted data occupancy rate is equal to or greater than a predetermined threshold. The communication band table may be stored in advance in the memory 32.

[0040] Every time the communication band setting unit 43 sets the probe communication band, it notifies the communication processing unit 44 of the set probe communication band.

[0041] The communication processing unit 44 transmits the collection target data stored in the memory 32 to the server 4 via the wireless communication terminal 23.

[0042] As described in the communication band setting unit 43, the communication processing unit 44 may determine whether the vehicle 2 has entered the collection target area by referring to the information indicating the collection target area and the latest positioning information. When the vehicle 2 enters the collection target area, the communication processing unit 44 transmits the collection target data for the collection target area designated by the collection instruction signal to the server 4 via the wireless communication terminal 23.

[0043] Specifically, when the probe data is specified as the data to be collected, the communication processing unit 44 transmits the probe data stored in the probe storage area of ​​the memory 32 to the server 4 via the wireless communication terminal 23 in order from the oldest to the newest.

[0044] In addition, when probe data and images are specified as data to be collected, the communication processing unit 44 transmits the probe data stored in the probe storage area of ​​the memory 32 and the images stored in the image storage area to the server 4 via the wireless communication terminal 23, in order from oldest to newest.

[0045] Furthermore, the images designated as the data to be collected may be partial images. In this case, the communication processing unit 44 generates partial images by cutting out an area that is estimated to represent the road surface from each of the images stored in the image storage area. The communication processing unit 44 then transmits the generated partial images, together with the probe data stored in the probe storage area of ​​the memory 32, to the server 4 via the wireless communication terminal 23 in order from the oldest to the newest.

[0046] Furthermore, the image designated as the data to be collected may be a feature image that emphasizes a notable area on the image. In this case, the communication processing unit 44 generates the feature image by executing a calculation for extracting a feature for each of the images stored in the image storage area. The calculation for extracting the feature includes, for example, an edge enhancement filter calculation and an edge detection filter calculation. The communication processing unit 44 then transmits the generated feature images together with the probe data stored in the probe storage area of ​​the memory 32 to the server 4 via the wireless communication terminal 23 in order from the oldest to the newest.

[0047] The communication processing unit 44 transmits the probe data to the server 4 by using the probe communication band set by the communication band setting unit 43. In this way, regardless of the size of the entire communication band available for transmitting the collection target data, the probe communication band set preferentially is used for transmitting the probe data, so that the probe data is uploaded to the server 4 in priority over other collection target data. Furthermore, when the collection target data includes data other than the probe data (image, partial image, or feature image), the communication processing unit 44 transmits the data to the server 4 by using the remaining communication band other than the probe communication band among the communication band available for transmitting the collection target data. On the other hand, when the collection target data is only the probe data, the communication processing unit 44 may transmit the probe data by using the entire communication band available for transmitting the collection target data.

[0048] For example, when the communication band is time-divisionable, the communication processing unit 44 sets the length of the subframe (hereinafter referred to as the probe subframe) used to transmit probe data in one frame to a length corresponding to the probe communication band. That is, the communication processing unit 44 sets the length of the probe subframe so that the probe communication band is the value obtained by multiplying the amount of data transmission per frame by the ratio of the length of the probe subframe to the length of one frame.

[0049] For each frame, the communication processing unit 44 transmits probe data to the server 4 via the wireless communication terminal 23 in a probe subframe, and transmits collection target data other than the probe data to the server 4 via the wireless communication terminal 23 in the remaining subframes of the frame.

[0050] 5(a) and 5(b) are diagrams showing an example of the relationship between the amount of untransmitted probe data and the collection target data uploaded to the server 4 per frame. In Fig. 5(a) and Fig. 5(b), the horizontal axis represents time.

[0051] 5(a), the untransmitted data occupancy rate RO is less than a predetermined threshold value Th. In this case, the communication processing unit 44 transmits, for each frame F, in the probe subframe S1, probe data obtained while the vehicle 2 is traveling for 60 seconds, and transmits, in the remaining subframe S2, images obtained while the vehicle 2 is traveling for 60 seconds.

[0052] 5(b), the untransmitted data occupancy rate RO is equal to or greater than the predetermined threshold Th. In this case, the communication processing unit 44 transmits, for each frame F, in the probe subframe S1, probe data obtained while the vehicle 2 travels for 120 seconds, and transmits, for the remaining subframe S2, images obtained while the vehicle 2 travels for 54 seconds.

[0053] In addition, if a multiplexing method other than time division is available for communication between the data collecting device 3 and the server 4, the communication processing unit 44 may secure the set communication band for the probe in accordance with that multiplexing method.

[0054] In addition, the communication processing unit 44 erases from the memory 32 the collection target data that was transmitted to the server 4 via the wireless communication terminal 23 .

[0055] When the vehicle 2 exits the collection target area, the communication processing unit 44 refers to the memory 32 to identify collection target data that has not been transmitted at the time of the exit. Then, the communication processing unit 44 ends the transmission of the collection target data when the transmission of the identified collection target data to the server 4 is completed. Note that, similar to the determination of whether the vehicle 2 has entered the collection target area, the communication processing unit 44 may determine whether the vehicle 2 has exited the collection target area by referring to the information representing the collection target area and the latest positioning information.

[0056] 6 is an operational flowchart of the process of generating probe data and storing the probe data and images in the data collection process. The processor 33 executes the process of generating probe data and storing the probe data and images in accordance with the following operational flowchart at predetermined intervals or each time the vehicle 2 travels a predetermined distance.

[0057] The image storage unit 41 of the processor 33 writes the image received by the data collection device 3 from the camera 21 into the image storage area of ​​the memory 32 (step S101). The detection unit 42 of the processor 33 detects a predetermined feature from the latest image and generates probe data representing the detected feature (step S102). The detection unit 42 then writes the generated probe data into the probe storage area of ​​the memory 32 (step S103).

[0058] 7 is an operational flowchart of the process related to uploading of collection target data in the data collection process. When the vehicle 2 enters a collection target area, the processor 33 executes the process related to uploading of the collection target data in accordance with the following operational flowchart.

[0059] The communication band setting unit 43 of the processor 33 sets a probe communication band based on the amount of untransmitted probe data stored in the probe storage area of ​​the memory 32 (step S201).

[0060] The communication processing unit 44 of the processor 33 uses the set communication band for the probe to transmit the series of unsent probe data stored in the probe storage area of ​​the memory 32 to the server 4 in preference to other collection target data (step S202). In addition, the communication processing unit 44 uses the remaining communication band out of the communication band available for transmitting the collection target data to transmit other collection target data, such as a series of images stored in the image storage area of ​​the memory 32, to the server 4 via the wireless communication terminal 23 (step S203). Then, the processor 33 ends the process related to uploading the collection target data.

[0061] Next, the server 4 will be described. The server 4 stores the probe data or images transmitted from the data collection device 3 mounted on each vehicle 2. The server 4 then generates or updates a map of the collection target area based on the probe data or images. Furthermore, the server 4 notifies each vehicle 2 of the collection target area. Furthermore, the server 4 designates the type of data to be collected for the collection target area, and notifies each vehicle 2 of a collection instruction signal indicating the designated type of data as collection target data.

[0062] 8 is a hardware configuration diagram of the server 4. The server 4 has a communication interface 51, a storage device 52, a memory 53, and a processor 54. The communication interface 51, the storage device 52, and the memory 53 are connected to the processor 54 via signal lines. The server 4 may further have input devices such as a keyboard and a mouse, and a display device such as a liquid crystal display.

[0063] The communication interface 51 is an example of a communication unit, and has an interface circuit for connecting the server 4 to the communication network 5. The communication interface 51 is configured to be able to communicate with the data collection device 3 mounted on each vehicle 2 via the communication network 5 and the wireless base station 6. That is, the communication interface 51 passes the collection target data and the like received from the data collection device 3 of each vehicle 2 via the wireless base station 6 and the communication network 5 to the processor 54. The communication interface 51 also transmits a collection instruction signal and the like received from the processor 54 to the data collection device 3 of each vehicle 2 via the communication network 5 and the wireless base station 6.

[0064] The storage device 52 is an example of a storage unit, and includes, for example, a hard disk device or an optical recording medium and an access device therefor. The storage device 52 stores type designation information and, for each of a plurality of road sections, collection target data collected for that road section. The storage device 52 may further store identification information of each vehicle 2. Furthermore, the storage device 52 may store a computer program for executing a data collection process on the server 4 side, which is executed on the processor 54. Furthermore, the storage device 52 may store a map that is generated or updated based on the collection target data.

[0065] The memory 53 is another example of a storage unit, and includes, for example, a non-volatile semiconductor memory and a volatile semiconductor memory. The memory 53 temporarily stores various data generated during the execution of the data collection process, and various data acquired through communication with each vehicle 2, such as probe data and images.

[0066] The processor 54 is an example of a control unit, and includes one or more CPUs (Central Processing Units) and their peripheral circuits. The processor 54 may further include other arithmetic circuits such as a logical arithmetic unit or a numerical arithmetic unit. The processor 54 executes the data collection process on the server 4 side.

[0067] The processor 54 generates a collection instruction signal to instruct each vehicle 2 to collect the data to be collected.

[0068] The processor 54 refers to type designation information corresponding to each collection target area. The processor 54 then identifies the type of collection target data designated for each collection target area based on the type designation information. The types of collection target data include an image representing the environment around the vehicle 2 generated by the camera 21 mounted on the vehicle 2, a partial image representing the road surface cut out from the image, or probe data representing features detected from the image. Therefore, the type designation information indicates, for each collection target area, the type of collection target data, which is either an image, a partial image, or probe data.

[0069] The processor 54 includes in the collection instruction signal information for designating the type of the identified data to be collected. If the type designation information indicates probe data, the processor 54 designates only the probe data as the data to be collected. If the type designation information indicates an image, the processor 54 designates the probe data and the image as the data to be collected. If the type designation information indicates a partial image, the processor 54 designates the probe data and the partial image as the data to be collected.

[0070] The processor 54 transmits the generated collection instruction signal to each vehicle 2 via the communication interface 51, the communication network 5 and the wireless base station 6.

[0071] The processor 54 may set the collection target area based on the number of probe data collected for each road section stored in the storage device 52. For example, the processor 54 may set the road section for which the number of probe data collected in the most recent predetermined period (for example, several weeks to several months) is less than a predetermined collection threshold as the collection target area. Alternatively, the processor 54 may set the road section for which the elapsed time since the previous update is equal to or greater than a predetermined elapsed time threshold, among the individual road sections shown on the map to be updated, as the collection target area. The processor 54 may then notify the data collection device 3 of each vehicle 2 of the set collection target area via the communication interface 51.

[0072] Furthermore, the processor 54 may generate or update a map using the collected probe data and images. In this case, the processor 54 aligns features represented in each of the probe data collected from one vehicle 2 for a continuous section with corresponding features represented in other probe data collected in the past or in the map to be updated. The processor 54 then identifies, as a newly installed feature, any feature represented in each of the probe data collected for the continuous section that does not have a corresponding feature in other probe data or in the map to be updated. The processor 54 then adds information (position and type) about the identified feature to the map to be generated or updated. The processor 54 may also identify, as removed features, any feature represented in each of the probe data collected for the continuous section that does not have a corresponding feature in the features represented in each of the probe data collected for the continuous section. The processor 54 may then delete information about the identified removed feature from the map to be updated.

[0073] As described above, the data collection device sets a probe communication band used for transmitting the probe data, which occupies a communication band of the communication line between the communication device and the server, based on the amount of untransmitted probe data. Then, the data collection device transmits a series of probe data stored in the memory to the server via the communication device in priority over a series of images stored in the memory, by using the probe communication band. Furthermore, the data collection device transmits collection target data other than the probe data to the server via the communication device, using the remaining communication band other than the probe communication band of the communication line. In this way, the probe communication band is set preferentially regardless of the size of the entire communication band available for transmitting the collection target data. Therefore, the data collection device can transmit a series of probe data representing features obtained over a certain continuous section to the server without any loss.

[0074] According to the modified example, after completing transmission of a series of probe data generated while the vehicle 2 is traveling a section of a predetermined distance or more through the collection target area, an image that was generated while the vehicle 2 was traveling through the collection target area and has not been transmitted may remain in the image storage area. In such a case, the communication processing unit 44 may transmit the image to the server 4 via the wireless communication terminal 23 in preference to other probe data stored in the probe storage area. This allows the data collection device 3 to suppress erasure of an image generated in the collection target area without transmitting it to the server 4, without reducing the accuracy of alignment on the server 4 side.

[0075] The communication processing unit 44 may obtain the length of the section in which each piece of probe data was generated by referring to the position of the vehicle 2 included in each piece of probe data transmitted to the server 4 from the time when the vehicle 2 enters the collection target area and starts transmitting the probe data. When the length reaches a predetermined distance, the communication processing unit 44 may prioritize transmitting the image as described above. The communication processing unit 44 may prioritize transmitting the image over transmitting the probe data by stopping transmitting the probe data until transmitting the image is completed.

[0076] According to another modification, the image storage unit 41 may discard the images received from the camera 21 without storing them in the image storage area while the vehicle 2 is traveling outside the collection target area. Similarly, the detection unit 42 may stop generating probe data while the vehicle 2 is traveling outside the collection target area. In this case, as described in the communication band setting unit 43, the image storage unit 41 and the detection unit 42 may refer to the information representing the collection target area and the latest positioning information to determine whether the position of the vehicle 2 is included in the collection target area.

[0077] As described above, those skilled in the art can make various modifications to the embodiments within the scope of the present invention. [Explanation of symbols]

[0078] 1 Data collection system 2 Vehicles 21 Camera 22 GPS receiver 23 Wireless communication terminals 3 Data collection equipment 31 Communication Interface 32 Memory 33 Processors 41 Image storage section 42 Detection unit 43 Communication Bandwidth Setting Section 44 Communication processing unit 4 Server 51 Communication Interface 52 Storage Device 53 Memory 54 processors 5. Communication Network 6 Radio base stations

Claims

1. an image storage unit that stores an image representing the surroundings of the vehicle generated by a camera mounted on the vehicle while the vehicle is traveling in a storage unit; a detection unit that detects a predetermined feature from the image, generates probe data representing the detected feature, and stores the generated probe data in the storage unit; a communication band setting unit that sets a probe communication band in a communication band of a communication line between a communication device mounted on the vehicle and the server in accordance with an amount of the series of probe data stored in the storage unit so that all of the series of probe data can be transmitted to a server via the communication device mounted on the vehicle; and a communication processing unit that transmits the series of probe data to the server via the communication device in priority to the series of images stored in the storage unit by using the probe communication band, and transmits the series of images to the server via the communication device by using a remaining communication band of the communication line other than the probe communication band; A data collection device having:

2. 2. The data collection device according to claim 1, wherein, after transmitting a series of the probe data generated over a section of a predetermined distance or more passing through a collection target area to the server, if an image that was generated when the vehicle traveled through the collection target area and has not been transmitted is stored in the memory unit, the communication processing unit transmits the untransmitted image to the server via the communication device in priority to other probe data stored in the memory unit.

3. 3 . The data collection device according to claim 1 , wherein the communication band setting unit is configured to set the probe communication band to a wider value as the amount of the series of probe data stored in the storage unit increases.

4. The data collection device of claim 3, wherein the communication bandwidth setting unit sets the probe communication bandwidth so that the amount of the probe data that can be transmitted to the server per unit time is greater than the amount of the probe data stored in the memory area per unit time in a most recent specified period when a ratio of the amount of data of the series of probe data occupying a memory area for storing the probe data in the memory unit becomes equal to or greater than a specified threshold value.

5. While the vehicle is traveling, an image showing the surroundings of the vehicle generated by a camera mounted on the vehicle is stored in a storage unit; Detecting a predetermined feature from the image, generating probe data representing the detected feature, and storing the generated probe data in the storage unit; a probe communication band occupying a communication band of a communication line between a communication device mounted on the vehicle and the server is set according to the amount of the series of probe data stored in the storage unit so that all of the series of probe data can be transmitted to a server via the communication device mounted on the vehicle; By using the probe communication band, the series of probe data is transmitted to the server via the communication device in priority to the series of images stored in the storage unit, and the series of images is transmitted to the server via the communication device by using the remaining communication band of the communication line other than the probe communication band. Data collection methods, including:

6. While the vehicle is traveling, an image showing the surroundings of the vehicle generated by a camera mounted on the vehicle is stored in a storage unit; Detecting a predetermined feature from the image, generating probe data representing the detected feature, and storing the generated probe data in the storage unit; a probe communication band occupying a communication band of a communication line between a communication device mounted on the vehicle and the server is set according to the amount of the series of probe data stored in the storage unit so that all of the series of probe data can be transmitted to a server via the communication device mounted on the vehicle; By using the probe communication band, the series of probe data is transmitted to the server via the communication device in priority to the series of images stored in the storage unit, and the series of images is transmitted to the server via the communication device by using the remaining communication band of the communication line other than the probe communication band. A data collection computer program that causes a processor mounted on the vehicle to execute the above steps.

7. A data collection system including a data collection device mounted on a vehicle and a server communicatively connected to the data collection device, The data collection device includes: A storage unit; an image storage unit that stores in the storage unit an image representing the surroundings of the vehicle generated by a camera mounted on the vehicle while the vehicle is traveling; a detection unit that detects a predetermined feature from the image, generates probe data representing the detected feature, and stores the generated probe data in the storage unit; a communication band setting unit that sets a probe communication band in a communication band of a communication line between a communication device and the server, in accordance with the amount of the series of probe data stored in the storage unit, so that all of the series of probe data can be transmitted to the server via the communication device mounted on the vehicle; and a communication processing unit that transmits the series of probe data to the server via the communication device in priority to the series of images stored in the storage unit by using the probe communication band, and transmits the series of images to the server via the communication device by using a remaining communication band of the communication line other than the probe communication band; A data collection system having:

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