Variable Speed Sign Value Prediction and Confidence Modeling

• US 20160042239A1
• Filed: 08/11/2014
• Published: 02/11/2016
• Est. Priority Date: 08/11/2014
• Status: Active Grant

• Current Assignee: HERE Global B.V. (Nokia Corporation)
• Original Assignee: HERE Global B.V. (Nokia Corporation)
• Inventors: Fowe, James Adeyemi, Stenneth, Leon Oliver
• Granted Patent: US 9,336,448 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 18/256 of results relating to different input data, e.g. multimodal recognition
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30236 Traffic on road, railway or crossing
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06V 10/811 the classifiers operating on different input data, e.g. multi-modal recognition
• CPC Class Codes: G06V 20/54 of traffic, e.g. cars on the road, trains or boats
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: G06V 20/582 of traffic signs
• CPC Class Codes: G08G 1/0112 from the vehicle, e.g. floating car data [FCD]
• CPC Class Codes: G08G 1/0129 for creating historical data or processing based on historical data
• CPC Class Codes: G08G 1/0141 for traffic information dissemination
• CPC Class Codes: G08G 1/095 Traffic lights
• CPC Class Codes: G08G 1/09623 Systems involving the acquisition of information from passive traffic signs by means mounted on the vehicle G08G1/0967 takes precedence
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096725 where the received information generates an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096741 where the source of the transmitted information selects which information to transmit to each vehicle
• CPC Class Codes: G08G 1/096775 where the origin of the information is a central station

Abstract

Systems, methods, and apparatuses are disclosed for predicting the value of a variable speed sign (VSS) and determining the predicted value'"'"'s associated confidence level. Highly assisted driving (HAD) vehicles may read or capture images of the VSS. The speed limit values, images, or videos of the VSS are reported and received by a network and database for analysis. A predicted speed limit value is determined for the variable speed sign from at least a portion of the received traffic data. A confidence level is also calculated for the predicted speed limit value for the variable speed sign.

Claims

1. A method comprising:

receiving a set of traffic data from at least one vehicle for a defined time period, the received traffic data comprising captured images, videos, or interpreted speed limit values of a variable speed sign;

determining, using a processor, a predicted speed limit value for the variable speed sign from at least a portion of the received traffic data; and

calculating a confidence level for the predicted speed limit value for the variable speed sign.

2. The method of claim 1, wherein the determining comprises computing a mode, a median, or a mean of the portion of the received traffic data.

3. The method of claim 1, further comprising:

prior to the determining of the predicted speed limit value, analyzing the captured images or the videos of the received traffic data to provide analyzed speed limit values of the variable speed sign.

4. The method of claim 1, further comprising:

reporting the predicted speed limit value and the calculated confidence level to at least one vehicle.

5. The method of claim 1, further comprising:

comparing the calculated confidence level with a threshold confidence level; and

reporting the predicted speed limit value to at least one vehicle when the calculated confidence level is greater than or equal to the threshold confidence level.

6. The method of claim 1, wherein the calculated confidence level is a factor of at least one of the following:

a) a number of observations in the set of traffic data, wherein a larger number of observations in the set of traffic data increases the confidence level;

b) a similarity of speed limit values in the observations within the set of traffic data, wherein the confidence level increases with an increase in the similarity of the speed limit values and decreases with a decrease in the similarity of the speed limit values;

c) a previously computed confidence level;

or

d) a collected time for each received traffic point within the set of traffic data, wherein the calculated confidence level decreases with an increase in a difference in time between the collected time for each received traffic point and a present time.

7. The method of claim 1, wherein the calculated confidence level, C_t, is:

8. The method of claim 1, wherein the calculated confidence level, C_t, is:

9. The method of claim 1, further comprising:

updating the set of traffic data with traffic data from vehicles in a second time period;

determining an updated predicted speed limit value for the variable speed sign using the real-time data and at least a portion of the received traffic data; and

calculating an updated confidence level for the predicted speed limit value for the variable speed sign.

10. The method of claim 9, wherein the portion of the received traffic data used in determining the updated predicted speed limit is from a collection time associated with each traffic data point of the received set of traffic data.

11. The method of claim 9, wherein when there is no additional traffic data in the second time period, the updated confidence level, C_t+1, is:

12. A method comprising:

receiving a set of traffic data from at least one vehicle in a first time period, the received traffic data comprising captured images, videos, or interpreted speed limit values of a variable speed sign;

determining, using a processor, a predicted speed limit value for the variable speed sign from a mode of at least a portion of the received traffic data;

calculating a confidence level for the predicted speed limit value for the variable speed sign;

comparing the calculated confidence level with a user'"'"'s confidence level; and

reporting the predicted speed limit value to a vehicle when the calculated confidence level is greater than or equal to the user'"'"'s confidence level.

13. An apparatus comprising:

at least one processor; and

at least one memory including computer program code for one or more programs;

the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to at least perform;

receive a set of traffic data from at least one vehicle for a defined time period, the received traffic data comprising captured images, videos, or interpreted speed limit values of a variable speed sign;

determine a predicted speed limit value for the variable speed sign from a portion of the received traffic data; and

calculate a confidence level for the predicted speed limit value for the variable speed sign.

14. The apparatus of claim 13, wherein the predicted speed limit value is determined through a computation of a mode, a median, or a mean of the portion of the received traffic data.

15. The apparatus of claim 13, wherein the at least one memory and the computer program code are configured to cause the apparatus to further perform:

report the predicted speed limit value and the calculated confidence level to a vehicle.

16. The apparatus of claim 13, wherein the at least one memory and the computer program code are configured to cause the apparatus to further perform:

compare the calculated confidence level with a threshold confidence level; and

report the predicted speed limit value to at least one vehicle when the calculated confidence level is greater than or equal to the threshold confidence level.

17. The apparatus of claim 13, wherein the calculated confidence level, C_t, is:

18. The apparatus of claim 13, wherein the calculated confidence level, C_t, is:

19. The apparatus of claim 13, wherein the at least one memory and the computer program code are configured to cause the apparatus to further perform:

update the set of traffic data with traffic data from vehicles in a second time period;

determine an updated predicted speed limit value for the variable speed sign using the real-time data and at least a portion of the received traffic data; and

calculate an updated confidence level for the predicted speed limit value for the variable speed sign.

20. The apparatus of claim 19, wherein the portion of the received traffic data used in determining the updated predicted speed limit is from a collection time associated with each traffic data point of the received set of traffic data.

21. The apparatus of claim 19, wherein when there is no additional traffic data in the second time period, the updated confidence level, C_t+1, is:

22. The apparatus of claim 13, wherein the calculated confidence level is a factor of at least one of the following:

a) a number of observations in the set of traffic data, wherein a larger number of observations in the set of traffic data increases the confidence level;

b) a similarity of speed limit values in the observations within the set of traffic data, wherein the confidence level increases with an increase in the similarity of the speed limit values and decreases with a decrease in the similarity of the speed limit values;

c) a previously computed confidence level;

or

d) a collected time for each received traffic point within the set of traffic data, wherein the calculated confidence level decreases with an increase in a difference in time between the collected time for each received traffic point and a present time.