Probe data reliability evaluation method

Abstract

To enable more accurate evaluation of probe data than conventional methods.SOLUTION: A computer-executed method for evaluating the reliability of probe data includes steps of: acquiring the probe data including at least a position, a speed, and a direction of travel of a vehicle; determining a first reliability regarding the positional accuracy in the direction of travel and a second reliability regarding the positional accuracy in the lateral direction based on the speed of the vehicle in the probe data; and associating the first reliability and the second reliability with the probe data.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for evaluating the reliability of probe data. [Background technology]

[0002] The accuracy of maps generated and updated based on probe data depends heavily on the accuracy of the probe data.

[0003] Patent Document 1 discloses a system for acquiring probe data that indicates the driving conditions when a vehicle travels on a target road section, in which reliability is set according to the driving lane. Patent Document 2 discloses a system for setting reliability of probe data based on the vehicle driving pattern. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-210905 [Patent Document 2] Japanese Patent Publication No. 2020-086476 [Patent Document 3] International Publication No. 2014 / 049843 [Patent Document 4] Japanese Patent Application Laid-Open No. 2016-053494 Summary of the Invention [Problem to be solved by the invention]

[0005] One aspect of the present disclosure aims to provide a technology that enables the accuracy of probe data to be evaluated more appropriately than conventional techniques. [Means for solving the problem]

[0006] One aspect of the present disclosure is a reliability evaluation method executed by a computer for evaluating the reliability of probe data, the reliability evaluation method including the steps of acquiring probe data including at least a vehicle position, speed, and direction of travel, determining a first reliability regarding the position accuracy in the direction of travel and a second reliability regarding the position accuracy in the lateral direction based on the vehicle speed in the probe data, and associating the first reliability and the second reliability with the probe data. [Effects of the Invention]

[0007] According to aspects of the present disclosure, the accuracy of probe data can be evaluated more appropriately than before. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of an information processing apparatus according to an embodiment. [Figure 2] 1 is a flowchart showing a processing flow according to an embodiment. [Figure 3] FIG. 10 is a diagram illustrating the reliability of a traveling direction position. [Figure 4] FIG. 10 is a diagram illustrating the reliability of a horizontal position. [Figure 5] FIG. 10 is a diagram illustrating the association between probe data and reliability. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present disclosure relates to a system for generating map data based on probe data obtained from sensors mounted on a vehicle, and in particular to a technology for evaluating the reliability of the probe data. The probe data is data obtained from sensors such as cameras, lidar sensors, radar sensors, and sonar mounted on a vehicle. Using high-performance sensors can produce highly reliable probe data. However, due to cost constraints, it is difficult to install high-performance sensors in many vehicles. Therefore, if low-performance sensors are used, it is expected that reliable and unreliable probe data will be mixed. In order to successfully extract reliable probe data and generate map data, it is necessary to accurately evaluate the reliability of the probe data.

[0010] (Overall composition) FIG. 1 is a diagram showing the configuration of an information processing device 100 in one embodiment. The information processing device 100 may be located on the cloud side, on the vehicle side, or both, with its functions distributed. The information processing device 100 acquires probe data, evaluates the reliability of each piece of probe data, and generates map data from the probe data taking the reliability into consideration. The information processing device 100 can be regarded as a probe data reliability evaluation device or a map data generation device.

[0011] The information processing device 100 is configured by a computer including a processor 110 and a memory 120. The memory 120 non-temporarily stores computer programs that cause the processor 110 to function as a probe data acquisition unit 111, a reliability evaluation unit 112, a storage unit 113, and a map generation unit 114.

[0012] FIG. 2 is a flowchart showing the flow of processing performed by the information processing device.

[0013] In step S201, the probe data acquisition unit 111 acquires probe data obtained from sensors such as cameras and radars mounted on a vehicle. The probe data acquisition unit 111 may acquire the probe data directly from the vehicle, or may acquire the probe data from an information server that stores the probe data acquired from the vehicle.

[0014] Probe data includes information about the vehicle and its surrounding environment. Examples of vehicle-related information include vehicle position, direction of travel, speed, acceleration, yaw rate, and other vehicle attitude (behavior) information. Examples of information about the vehicle's surrounding environment include the type, position, shape, and other attributes of features such as lane markings, traffic lights, and signs.

[0015] In step S202, the reliability evaluation unit 112 calculates the reliability of each piece of probe data acquired by the probe data acquisition unit 111. Here, the reliability evaluation unit 112 calculates multiple reliabilities from different perspectives for one piece of probe data. Examples of multiple reliabilities include the reliability of the vehicle's position along the traveling direction (first reliability) and the reliability of the vehicle's position along the lateral direction (direction perpendicular to the traveling direction) (second reliability). The traveling direction can also be expressed as the direction along the road or lane.

[0016] Before explaining how to calculate reliability, we will explain the trends observed in experiments regarding the accuracy of probe data. In the experiments, probe data was collected using two types of sensors mounted on a vehicle. One sensor was a relatively low-cost sensor that was intended to be used to collect probe data in actual operation, and the other was a high-precision sensor used for validation. Because the former sensor is the sensor used to actually obtain probe data, the data obtained from the former sensor will be referred to here as probe data. On the other hand, the data obtained from the latter sensor will be referred to as validation data. The validation data can be considered accurate and can therefore be used to evaluate the error of the probe data.

[0017] The experimental results showed that although the amount of error in vehicle position varies depending on the vehicle speed for both forward and lateral positions, the correlation between speed and error tends to differ between forward and lateral positions.

[0018] Regarding the accuracy of the forward position, it was first found that when the vehicle speed is close to 0 km / h, for example, between 0 and 1.5 km / h, the accuracy drops significantly. As the vehicle speed increases, the error decreases and the accuracy improves, and it was found that a highly accurate position with little error can be obtained above a certain speed. For example, results were obtained that met the required accuracy above 5 km / h. On the other hand, it was also found that once the speed exceeds a certain threshold, for example, 30 km / h, the error increases as the speed increases.

[0019] Regarding the accuracy of the lateral position, it was found that when the vehicle speed was close to 0 km / h, the accuracy was comparable up to a certain speed. While the position accuracy in this speed range was insufficient, the error was not so large that it was unusable. The range in which this accuracy was achieved was, for example, 0 to 10 km / h. After that, as the vehicle speed increased, the error decreased and the accuracy improved, and it was found that above a certain speed, a highly accurate position with little error could be obtained. For example, results were obtained that met the required accuracy above 15 km / h. Furthermore, the error did not increase above 15 km / h.

[0020] Based on the above experimental results, in this embodiment, the reliability of the traveling direction position and the lateral direction position is determined as follows: In this embodiment, the minimum value of the reliability is set to 0, and the maximum value is set to 1.

[0021] FIG. 3 is a diagram illustrating the reliability of the traveling direction position. As shown in the figure, when the vehicle speed is less than a first reliability (e.g., 1.5 km / h), the reliability is set to 0. When the vehicle speed is greater than a first threshold and less than a second threshold (e.g., 5 km / h), the reliability increases linearly and monotonically from 0 to 1. When the vehicle speed is greater than the second threshold and less than a third threshold (e.g., 30 km / h), the reliability is set to 1. When the vehicle speed is greater than the third threshold, the reliability decreases linearly and monotonically. Here, if the allowable error differs depending on the type of road the vehicle is traveling on, the reliability decrease rate may be changed. For example, in FIG. 3, when the vehicle speed is greater than the third threshold, the reliability decrease rate (302) for expressways is set to be smaller than the decrease rate (301) for general roads. When the vehicle speed is greater than the third threshold, the reliability decreases at a rate such that the reliability becomes 0 when the vehicle speed is 80 km / h, but when the vehicle speed is greater than the expressway, the reliability decreases at a rate such that the reliability becomes 0 when the vehicle speed is 120 km / h. It should be noted that the rate of decrease in reliability when the vehicle speed is greater than the third threshold may be set to the same regardless of the type of road on which the vehicle is traveling.

[0022] FIG. 4 is a diagram illustrating the reliability of the lateral position. As shown in the figure, when the vehicle speed is smaller than a fourth threshold (for example, 10 km / h), the reliability is set to a fixed value (for example, 0.3). When the vehicle speed is larger than the fourth threshold and smaller than a fifth threshold (for example, 15 km / h), the reliability increases linearly and monotonically. When the vehicle speed is larger than the fifth threshold, the reliability is set to 1. Note that the reliability of the lateral position may be set to increase monotonically (broadly defined monotonically) according to the vehicle speed.

[0023] Note that the threshold values ​​and specific reliability values ​​shown here are merely examples and may be changed as appropriate depending on the required position accuracy and the accuracy of the sensors used. Also, when monotonically increasing or decreasing the reliability depending on the vehicle speed, an example is shown in which the reliability is linearly increased or decreased, but as long as it is monotonically increasing or decreasing, it does not need to be changed linearly. A quadratic function or a higher-order polynomial function, an exponential function, or a stepwise monotonically increasing or decreasing function can be used.

[0024] In step S203, the storage unit 113 stores the calculated reliability in association with the probe data from which the calculation was made. Fig. 5 is a diagram showing an example of the association. As shown in the figure, an identifier (data ID) for identifying the probe data and the reliability of the traveling direction position and the lateral direction position are stored. The reliability of the probe data is associated with the data ID of the probe data and stored. Instead of associating the data ID with the reliability, the reliability may be added to the probe data. The data may be stored inside the information processing device 100, in an information server that collects the probe data, or in another device.

[0025] In step S204, the map generation unit 114 generates map data from the probe data, taking into account the reliability of the probe data. The map generation unit 114 integrates information from multiple pieces of probe data to generate information about a single feature. In this process, the map generation unit 114 generates feature information from the probe data after excluding probe data whose reliability is below a reference value or weighting the data according to the reliability. The reliability of the probe data includes the reliability of the forward position and the reliability of the lateral position. The reliability of the probe data may focus on only one of the reliability levels, or may focus on an integrated reliability obtained by integrating (e.g., averaging) these reliability levels. Different standards may be applied to each reliability level. Different standards may also be applied depending on the feature being calculated. The location and size information of the feature is determined based on the position information of the probe car and the relative position and size of the feature relative to the probe car. Therefore, the positional accuracy of the probe data is important for generating highly accurate map data. It is conceivable that the required accuracy for the forward position and the lateral position differs depending on the type of feature. For example, for some features, the accuracy of the lateral position may be important, for other features the accuracy of the forward position may be important, and for still other features the accuracy of both positions may be important. In this embodiment, the reliability (accuracy) of the forward and lateral position is calculated for each piece of probe data, making it possible to use appropriate probe data depending on the feature information of the desired target, and as a result, making it possible to generate high-quality map data.

[0026] (Effects of the embodiment) According to this embodiment, multiple reliability levels from different perspectives are calculated for a single piece of probe data. This allows processing based on an appropriate reliability level depending on the intended use of the probe data, enabling the generation of high-quality map data. Furthermore, this embodiment proposes a reliability calculation method for each of the forward and lateral positions based on new findings in the probe data, enabling a more appropriate evaluation of the reliability of the probe data than in the past, ultimately enabling the generation of high-quality map data.

[0027] (Other embodiments) The above-described embodiment is merely an example, and the present disclosure can be modified and implemented as appropriate within the scope that does not deviate from the gist of the disclosure.

[0028] In the above embodiment, the information processing device 100 performs both the reliability evaluation of the probe data and the map generation, but the reliability evaluation and the map generation may be performed by different devices or systems.

[0029] The present disclosure can also be realized by providing a computer program implementing the functions described in the above embodiments to a computer, and having one or more processors in the computer read and execute the program. Such a computer program may be provided to the computer via a non-transitory computer-readable storage medium connectable to the computer's system bus or via a network. Non-transitory computer-readable storage media include, for example, any type of disk, such as a magnetic disk (e.g., a floppy disk, a hard disk drive (HDD), etc.), an optical disk (e.g., a CD-ROM, a DVD disk, a Blu-ray disk), a read-only memory (ROM), a random-access memory (RAM), an EPROM, an EEPROM, a magnetic card, a flash memory, an optical card, or any type of medium suitable for storing electronic instructions. [Explanation of symbols]

[0030] 100: Information processing device 110: Processor 111: Probe data acquisition unit 112: Reliability evaluation unit 113: Memory unit 114: Map generation unit

Claims

1. 1. A computer-implemented reliability evaluation method for evaluating reliability of probe data, comprising: acquiring probe data including at least a vehicle's position, speed, and heading; determining a first confidence level regarding a position accuracy in a forward direction and a second confidence level regarding a position accuracy in a lateral direction based on the vehicle speed in the probe data; associating the first reliability and the second reliability with the probe data; A reliability evaluation method including:

2. The first reliability is 0 if the vehicle speed is less than a first threshold; When the vehicle speed is greater than the first threshold and less than the second threshold, the vehicle speed monotonically increases. If the vehicle speed is greater than the second threshold and less than the third threshold, the value is 1; When the vehicle speed is greater than the third threshold, the vehicle speed monotonically decreases. It is determined as follows:

2. The reliability evaluation method according to claim 1.

3. The decrease rate of the first reliability may be calculated to vary depending on the type of road on which the vehicle is traveling, When the vehicle speed is greater than the third threshold, the reduction rate when the road on which the vehicle is traveling is an expressway is smaller than the reduction rate when the road on which the vehicle is traveling is an ordinary road.

3. The reliability evaluation method according to claim 2.

4. the second reliability is determined so as to monotonically increase with respect to the vehicle speed; 2. The reliability evaluation method according to claim 1.

5. The second reliability is If the vehicle speed is less than a fourth threshold, the vehicle speed is a constant. When the vehicle speed is greater than the fourth threshold and less than the fifth threshold, the vehicle speed monotonically increases. 1 if the vehicle speed is greater than the fifth threshold. It is determined as follows:

2. The reliability evaluation method according to claim 1.

Images