System and method for on-road traffic density analytics using video stream mining and statistical techniques

• US 8,942,913 B2
• Filed: 09/13/2012
• Issued: 01/27/2015
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: Infosys Limited
• Original Assignee: Infosys Limited
• Inventors: Hota, Rudra Narayan, Pisipati, Radha Krishna, Jonna, Kishore
• Primary Examiner(s): Black, Thomas G
• Assistant Examiner(s): PAYNE, ROBERT T
• Application Number:
  US13/614,267
• Publication Number:
  US 20130073192A1
• Time in Patent Office: 866 Days
• Field of Search: 701/118, 701/117, 701/16, 701/532, 701/199, 340/907, 340/933, 340/905, 340/901, 340/934, 340/936, 348/155, 348/21.2, 348/170, 348/207, 348/148, 348/211.2, 455/414.3, 455/414, 455/456.2, 346/107, 240/961
• US Class Current: 701/118
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

A method and system for analyzing on-road traffic density are provided. The method involves allowing a user to select a video image capturing device and coordinates in a video image frame captured by the video image capturing device such that the coordinates form a region of interest (ROI). The ROI is processed to generate a confidence value and a traffic density value. The traffic density value is compared with a first set of threshold values. Based on the comparison, the traffic density values at different instants in a time window are displayed to enable monitoring of the traffic trend.

Claims

1. method for analyzing on-road traffic density comprising:

receiving, by a traffic management computing device, a user selection of a video image capturing device from among a plurality of video image capturing devices;

receiving, by the traffic management computing device, a user selection of coordinates in one of one or more video image frames of an on-road traffic scenario captured by the selected video image capturing device such that the coordinates form a closed region of interest;

the

segmenting, by the traffic management computing device, the region of interest into one or more overlapping sub-windows;

converting, by the traffic management computing device, the one or more overlapping sub-windows into one or more feature vectors through a textural feature extraction technique;

generating, by the traffic management computing device, at least a traffic confidence value or no traffic confidence value for each of the feature vectors to classify the sub-windows as having a high traffic value or a low traffic value by a traffic density classifier;

computing, by the traffic management computing device, at least a traffic density value depending on a number of the sub-windows with a high traffic value and a total number the of sub-windows within the region of interest;

comparing, by the traffic management computing device, the traffic density value with a first set of threshold values to categorize the video image frame as having low, medium or high traffic; and

displaying, by the traffic management computing device, traffic density values at different instants in a time window to enable monitoring of a traffic trend.

2. The method according to claim 1, further comprising, based on the computed traffic density value:

estimating, by the traffic management computing device, a traffic state at a junction;

estimating, by the traffic management computing device, a travel time between any two consecutive junctions on a route, wherein the route includes a plurality of junctions;

determining, by the traffic management computing device, an optimized route between a selected source and a selected destination on the route; and

analyzing, by the traffic management computing device, an impact of congestion at one junction on another junction on the route.

3. The method according to claim 2, wherein estimating the traffic state at a junction comprises:

receiving, by the traffic management computing device, traffic density values of the video image frames captured by the selected video image capturing device for a time window from a database; and

comparing, by the traffic management computing device, the traffic density values with a second set of threshold values to classify the traffic state of the time window into one of a plurality of predefined traffic states, wherein the second set of threshold values include a minimum threshold value and a maximum threshold value.

4. The method according to claim 3, wherein the plurality of predefined traffic states comprise a free state or a fluid state or a congestion state.

5. The method according to claim 4, wherein the traffic state of the time window is classified as:

the free state when the traffic density values in the time window are below the minimum threshold value of the second set of threshold values;

the fluid state when the traffic density values in the time window are between the maximum and minimum threshold values of the second set of threshold values, and

the congestion state when the traffic density values in the time window are above the maximum threshold value of the second set of threshold values.

6. The method according to claim 2, wherein estimating the travel time comprises:

adding, by the traffic management computing device, a time taken to travel between the any two consecutive junctions on the route and the traffic states between the any two consecutive junctions on the route at different instants of time.

7. The method according to claim 2, wherein determining the optimized route between the selected source and the selected destination comprises:

identifying, by the traffic management computing device, an optimum path between the selected source and the selected destination using one of static estimation or dynamic estimation.

8. The method according to claim 7, wherein the static estimation identifies a best route based on a least amount of time taken to reach the destination and the traffic density values of the junctions between the selected source and the selected destination.

9. The method according to claim 7, wherein the dynamic estimation identifies the best route by utilizing a graph theory algorithm.

10. The method according to claim 2, wherein analyzing the impact of congestion comprises:

selecting, by the traffic management computing device, a congestion time window tc;

computing, by the traffic management computing device, a travel time t1 between a pair of junctions J1 and J2 using historical data;

obtaining, by the traffic management computing device, traffic density values D1 for the junction J1 between timestamps t and t+tc, and traffic density values D2 for the junction J2 between timestamps t+t1 and t+t1+tc, where t is the time at any given instant;

determining, by the traffic management computing device, a correlation value between the traffic density values D1 and D2; and

comparing, by the traffic management computing device, the correlation value with a third set of threshold values to categorize the impact of congestion as one of high, medium, low or negative.

11. The method according to claim 10, wherein the third set of threshold values comprises a minimum threshold value below which the congestion impact at J2 on J1 is low and a maximum threshold value above which the congestion impact at J2 on J1 is high.

12. The method according to claim 10, wherein the correlation value is negative when congestion impact is present at J1 due to traffic at J2.

13. The method according to claim 1, further comprising:

receiving, by the traffic management computing device, as user selection of one among a plurality of field of views of the selected video image capturing device prior to recieving the user selection of coordinates.

14. The method according to claim 1, wherein the region of interest is a flexible convex shaped polygon.

15. The method according to claim 1, further comprising:

enhancing, by the traffic management computing device, contrast in a shadowed region in the region of interest; and

smoothing, by the traffic management computing device, the region of interest for image noise reduction prior to segmentation of the region of interest into sub-windows.

16. The method according to claim 1, wherein the textural feature extraction technique utilizes a histogram of a plurality of Oriented Gradient descriptors in the sub-windows for converting the sub-windows into feature vectors.

17. The method according to claim 1, wherein generating the trafficc confidence value and the no traffic confidence value comprises:

utilizing, by the traffic management computing device, a non-linear interpolation to provide weightage to the sub-windows based on the distance of the sub-windows from a field of view of the selected video image capturing device.

18. The method according to claim 1, wherein the traffic density classifier is pre-trained with a number of manually selected video image data with and without the presence of traffic objects.

19. The method according to claim 1, wherein the first set of threshold values comprise a minimum threshold value below which the traffic density is low and a maximum threshold value above which the traffic density is high.

20. The method according to claim 1, further comprising:

generating, by the traffic management computing device, an alarm message when the traffic density value exceeds the first set of threshold values.

21. A method for re-training a traffic density classifier comprising:

collecting, by a traffic management computing device, a set of misclassified video image frames captured by an image capturing device from among a plurality of image capturing devices; and

utilizing, by the traffic management computing device;

a reinforcement learning to train the traffic density classifier with a valid set of video image frames corresponding to predefined settings of the image capturing device.

22. The method according to claim 21, wherein collecting the set of misclassified video image frames comprises:

cross-validating, by the traffic management computing device, the classified video image frames with a master classifier, where the master classifier is pre-trained with video image frames of multiple texture and color features.

23. The method according to claim 21, wherein the predefined settings of the image capturing device comprise one or more of a view angle, a distance, or a height.

24. road traffic management computing device comprising:

a processor coupled to a memory and configured to execute programmed instructions stored in the memory, comprising;

receiving a user selection of a video image capturing device from among a plurality of video image capturing devices communicatively coupled to the traffic management computing device;

receiving a user selection of coordinated in one of one or more video image frames of an on-road traffic scenario captured by the selected video image capturing device such that the coordinates form a closed region of interest;

segmenting the region of interest into on or more overlapping sub-windows;

converting the one or more overlapping sub-windows into one or more feature vectors through a textural feature extraction technique;

generating at least a traffic confidence value or no traffic confidence value for each of the feature vectors to classify the sub-windows as having at least a high traffic value or a low traffic value by a traffic density classifier;

computing a traffic density value depending on a number of the sub-windows with a high traffic value and a total number the sub-windows within the region of interest;

comparing the traffic density value with a first set of threshold values to categorize the video image frame as having low, medium or high traffic; and

displaying traffic density values at different instants in a time window to enable monitoring of a traffic end.

25. The device according to claim 24, wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:

estimating a traffic state at a junction;

estimating a travel time between any two consecutive junctions on a route, wherein the route includes a plurality of junctions;

determining an optimized route between a selected source and a selected destination on the route; and

analyzing an impact of congestion at one junction on another junction on the route.

26. The device according to claim 25, wherein estimating the traffic state at a junction comprises:

receiving traffic density values of the video image frames captured by the selected video image capturing device for a time window from a database;

comparing the traffic density values with a second set of threshold values to classify the traffic state of the time window into one of a plurality of predefined traffic states, wherein the second set of threshold values include a minimum threshold value and a maximum threshold value.

27. The device according to claim 26, wherein the plurality of predefined traffic states comprise a free state, a fluid state or a congestion state.

28. The device according to claim 26, wherein the traffic state of the time window is classified as:

the free state when the traffic density values in the time window are below the minimum threshold value of the second set of threshold values;

the fluid state when the traffic density values in the time window are between the maximum and minimum threshold values of the second set of threshold values; and

the congestion state when the traffic density values in the time window are above the maximum threshold value of the second set of threshold values.

29. The device according to claim 25, wherein estimating the travel time comprises:

adding a time taken to travel between the any two consecutive junctions on the route and the traffic states between the any two consecutive junctions on the route at different instants of time.

30. The device according to claim 25, wherein planning an optimized route between the selected source and the selected destination comprises:

identifying an optimum path between the selected source and the selected destination using one of static estimation or dynamic estimation.

31. The device according to claim 30, wherein the static estimation identifies a best route based on a least amount of time taken to reach the selected destination and the traffic density values of the junctions between the selected source and the selected destination.

32. The device according to claim 30, wherein the dynamic estimation identifies the best route by utilizing a graph theory algorithm.

33. The device according to claim 25, wherein analayzing the impact of congestion comprises:

selecting a congestion time window tc;

computing a travel time t1 between a pair of junctions J1 and J2 from using historical data;

obtaining traffic density values D1 for junction J1 between timestamps t and t+tc, and traffic density values D2 for junction J2 between timestamps t+t1 and t+t1+tc, where t is the time at any given instant

determing a correlation value between the traffic density values D1 and D2; and

comparing the correlation value with a third set of threshold values to categorize a congestion impact as one of high, medium, low or negative.

34. The device according to claim 33, wherein the third set of threshold values comprises a minimum threshold value below which the congestion impact at J2 on J1 is low and a maximum threshold value above which the congestion impact at J2 on J1 is high.

35. The device according to claim 33, wherein there is congestion impact at J1 due to traffic at J2 when the correlation value is negative.

36. The device according to claim 24, wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:

receiving a user selection of one among the plurality of fields of view for the selected video image capturing device.

37. The device according to claim 24, wherein the region of interest is a flexible convex shaped polygon.

38. The device according to claim 24, wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:

enhancing contrast in a shadowed region in the region of interest; and

smoothing the region of interestfor image noise reduction prior to segmentation of the region of interest into sub-windows.

39. The device according to claim 24, wherein the textural feature extraction technique utilizes a histogram of a plurality of Oriented Gradient descriptors in the sub-windows while converting the sub-windows into feature vectors.

40. The device according to claim 24, wherein generating the traffic confidence value or no-traffic confidence value comprises:

utilizing a non-linear interpolation to provide weightage to the sub-windows based on the distance of the sub-windows from a field of view of the selected video image capturing device.

41. The device according to claim 24, wherein the traffic density classifier is pre-trained with a number of manually selected video image data with and without the presence of traffic objects.

42. The device according to claim 24, wherein the first set of threshold values comprise a minimum threshold value below which the traffic density is low and a maximum threshold above which the traffic density is high.

43. The device according to claim 24, wherein the processor is further configured to execute programmed instructions stored in the memory further comprising:

generating an alarm message when the traffic density value exceeds the first set of threshold values.

44. A traffic management computing device comprising:

a processor coupled to a memory and configured to execute programmed instructions stored in the memory, comprising;

collecting a set of misclassified video image data of a video image capturing device from among plurality of video image capturing devices; and

utilizing a reinforcement learning to train a traffic density classifier with a valid set of video image data for corresponding to predefined settings of the video image capturing devices.

45. The device according to claim 44, wherein collecting the set of misclassified video image comprises:

cross-validating the classified video image data with a master classifier, where the master classifier is trained with video image data of multiple textures and color features.

46. The device according to claim 45, wherein the predefined settings of the image capturing device comprise one or more of a view angle, a distance, or a height.

47. A non-transitory computer readable medium program having stored thereon instructions for analyzing on-road traffic density comprising machine executable code which when executed by a processor, causes the processor to perform steps comprising:

receiving a user selection of a video image capturing device from among a plurality of video image capturing devices communicatively coupled to the traffic management computing device;

receiving a user selection of coordinated in one of one or more video image frames of an on-road traffic scenario captured by the selected video image capturing device such that the coordinates form a closed region of interest;

segmenting the region of interest into on or more overlapping sub-windows;

converting the one or more overlapping sub-windows into one or more feature vectors through a textural feature extraction technique;

generating at least a traffic confidence value or no traffic confidence value for each of the feature vectors to classify the sub-windows as having at least a high traffic value or a low traffic value by a traffic density classifier;

computing a traffic density value depending on a number of the sub-windows with a high traffic value and a total number the sub-windows within the region of interest;

comparing the traffic density value with a first set of threshold values to categorize the video image frame as having low, medium or high traffic; and

displaying traffic density values at different instants in a time window to enable monitoring of a traffic end.

48. The medium according to claim 47, wherein estimating the traffic density value further comprises:

estimating a traffic state at a junction;

estimating a travel time between any two consecutive junctions on a route, wherein the route includes a plurality of junctions;

determing an optimized route between a selected source and a selected destination on the route; and

analyzing an impact of congestion at one junction on another junction on the route.

49. A non-transitory computer readable medium program having stored thereon instructions for re-training a traffic density classifier comprising machine executable code which when executed by a processor, causes the processor to perform steps comprising:

collecting a set of misclassified video image frames captured by an image capturing device from among a plurality of image capturing devices; and

utilizing a reinforcement learning to train the traffic density classifier with a valid set of video image frames corresponding to predefined settings of the image capturing device.

50. The medium according to claim 49, wherein collecting the set of misclassified video image frames comprises:

cross-validating the classified video image frames with a master classifier, where the master classifier is pre-trained with video image frames of multiple textures and color features.