Method, apparatus and computer program product for determining a semantic privacy index

1. A method for determining a semantic privacy index, the method comprising:

receiving information regarding a trajectory;

after the trajectory has been map matched to a portion of a road network, associating contextual information comprising one or more map features with the trajectory; and

providing the information regarding the trajectory and the contextual information comprising the one or more map features to a risk estimation model in order to generate the semantic privacy index that quantifies a risk associated with re-identification of the trajectory following anonymization of the trajectory.

2. A method according to claim 1 wherein the contextual information comprises information having a spatial relationship to the trajectory.

3. A method according to claim 2 wherein the information having the spatial relationship comprises information regarding one or more points of interest (POIs) located along the trajectory.

4. A method according to claim 2 wherein the information having the spatial relationship comprises geo-tagged text or image data.

5. A method according to claim 1 wherein the contextual information comprises information having a temporal relationship to the trajectory.

6. A method according to claim 1 wherein the contextual information defines a relationship between two or more points of the trajectory.

7. A method according to claim 1 wherein the contextual information associated with the trajectory comprises information specific to a user of a probe device that collects a plurality of probe points that form the trajectory.

8. A method according to claim 1 further comprising causing the information regarding the trajectory to be anonymized in a manner dependent upon the semantic privacy index.

9. A method according to claim 1 further comprising training the risk estimation model based upon indications for the map features as to the risk associated with re-identification of the trajectory occasioned by the map features following anonymization of the trajectory.

10. An apparatus configured to determine a semantic privacy index, the apparatus comprising at least one processor and at least one non-transitory memory including computer program code instructions, the computer program code instructions configured to, when executed by the at least one processor, cause the apparatus to:

receive information regarding a trajectory;

after the trajectory has been map matched to a portion of a road network, associate contextual information comprising one or more map features with the trajectory; and

provide the information regarding the trajectory and the contextual information comprising the one or more map features to a risk estimation model in order to generate the semantic privacy index that quantifies a risk associated with re-identification of the trajectory following anonymization of the trajectory.

11. An apparatus according to claim 10 wherein the contextual information comprises information having a spatial relationship to the trajectory.

12. An apparatus according to claim 10 wherein the contextual information comprises information having a temporal relationship to the trajectory.

13. An apparatus according to claim 10 wherein the contextual information defines a relationship between two or more points of the trajectory.

14. An apparatus according to claim 10 wherein the contextual information associated with the trajectory comprises information specific to a user of a probe device that collects a plurality of probe points that form the trajectory.

15. An apparatus according to claim 10 wherein the computer program code instructions are further configured to, when executed by the at least one processor, cause the apparatus to cause the information regarding the trajectory to be anonymized in a manner dependent upon the semantic privacy index.

16. An apparatus according to claim 10 wherein the computer program code instructions are further configured to, when executed by the at least one processor, cause the apparatus to train the risk estimation model based upon indications for the map features as to the risk associated with re-identification of the trajectory occasioned by the map features following anonymization of the trajectory.

17. A computer program product configured to determine a semantic privacy index, the computer program product comprising at least one non-transitory computer-readable storage medium having computer-executable program code instructions stored therein, wherein the computer-executable program code instructions are configured to:

receive information regarding a trajectory;

after the trajectory has been map matched to a portion of a road network, associate contextual information comprising one or more map features with the trajectory; and

provide the information regarding the trajectory and the contextual information comprising the one or more map features to a risk estimation model in order to generate the semantic privacy index that quantifies a risk associated with re-identification of the trajectory following anonymization of the trajectory.

18. A computer program product according to claim 17 wherein the contextual information associated with the trajectory comprises information specific to a user of a probe device that collects a plurality of probe points that form the trajectory.

19. A computer program product according to claim 17 wherein the computer-executable program code instructions are further configured to cause the information regarding the trajectory to be anonymized in a manner dependent upon the semantic privacy index.

20. A computer program product according to claim 17 wherein the computer-executable program code instructions are further configured to train the risk estimation model based upon indications for the map features as to the risk associated with re-identification of the trajectory occasioned by the map features following anonymization of the trajectory.