Memory management in event recording systems

1. A vehicle event recorder configured to be mounted in a vehicle, the vehicle event recorder comprising:

a video camera having a field-of-view that includes an environment about the vehicle, the video camera configured to acquire consecutive frames of visual information representing the environment about the vehicle;

a buffer memory configured to electronically store the consecutively acquired frames of visual information;

a long term storage memory configured to selectively store a subset of frames of the consecutively acquired frames of visual information

one or more sensors configured to generate output signals conveying information related to vehicle events; and

a controller configured to:

effectuate storage of the consecutively acquired frames of visual information in the buffer memory;

facilitate interleaved overwriting of less valuable individual frames of the consecutively acquired frames of visual information stored in the buffer memory with additional frames acquired by the video camera, wherein value of individual frames of the consecutively acquired frames decreases:

i. with increasing time away from a time of a given vehicle event, and

ii. with presence of one or more adjacent frames in the consecutively acquired frames that convey substantially similar visual information;

detect the given vehicle events based on the output signals; and

responsive to detecting the a given vehicle event, transfer the frames of visual information stored in the buffer memory to the long term storage memory, the transferred frames of visual information including frames of visual information for a period of time that begins before the given vehicle event and lasts until after the given vehicle event.

2. The vehicle event recorder of claim 1 , wherein the controller is configured such that the less valuable individual frames of the consecutively acquired frames are not the oldest frames stored in the buffer memory.

3. The vehicle event recorder of claim 1 , wherein the controller is configured to assign individual value scores to the consecutively acquired frames of visual information stored in the buffer memory, adjust the individual value scores based on an individual frame's age, and facilitate interleaved overwriting of the additional frames acquired by the video camera based on the adjusted individual value scores.

4. The vehicle event recorder of claim 3 , wherein the controller is configured to assign the individual value scores to the consecutively acquired frames of visual information such that every n-th frame, where n is an integer, is assigned a higher score than frames that immediately precede and immediately follow the n-th frame, which results in a first portion of the frames of visual information stored in the buffer memory having a first higher frame storage rate and a second portion of the frames of visual information stored in the buffer memory having a second lower frame storage rate that is less than or equal to the first higher frame rate divided by n.

5. The vehicle event recorder of claim 4 , wherein the controller is configured such that the second storage density has a variable frame storage rate that corresponds to one or more of the proximity in time to the time of the given vehicle event, a distance travelled by the vehicle, a speed of the vehicle, a pixel difference between consecutively acquired frames of visual information, or a geographic location of the vehicle.

6. The vehicle event recorder of claim 1 , wherein the controller is configured to assign individual value scores to individual frames of visual information stored in the buffer memory based on a pixel difference between consecutive individual frames acquired by the video camera such that a second individual additional frame that consecutively follows a first individual additional frame and has a low pixel difference relative to the first individual additional frame is assigned a low value score and a third individual additional frame that consecutively follows the first individual additional frame and has a high pixel difference relative to the first individual additional frame is assigned a high value score.

7. The vehicle event recorder of claim 1 , wherein the controller is configured to assign individual value scores to individual frames of visual information stored in the buffer memory based on one or more of whether the vehicle was moving when the video camera acquired the individual frames of visual information, whether an operator was present in the vehicle when the video camera acquired the individual frames of information, a distance travelled by the vehicle, a speed of the vehicle, or a geographic location of the vehicle.

8. The vehicle event recorder of claim 1 , further comprising a flush module configured to facilitate the transfer of the frames of visual information from the buffer memory to the long term storage memory, the flush module configured to facilitate the transfer of the frames of visual information from the buffer memory, responsive to the detection of the given vehicle event, at a transfer rate that exceeds a rate at which the frames of visual information are acquired by the video camera.

9. The vehicle event recorder of claim 8 , wherein the flush module is configured to start the transfer immediately after the detection of the given vehicle event rather than waiting for all video frames associated with the given vehicle event to be stored in the buffer memory.

10. The vehicle event recorder of claim 8 , wherein the flush module is configured, responsive to detection of a second vehicle event in time proximity to the given vehicle event, to dynamically extend a duration of the period of time that begins before the given vehicle event and lasts until after the second vehicle event such that the transferred frames of visual information include frames of visual information for an extended period of time that begins before the given vehicle event and lasts until after the second vehicle event.

11. A method for storing frames of visual information with a vehicle event recording system, the method comprising:

acquiring consecutive frames of visual information representing an environment about a vehicle with a video camera of the vehicle event recording system;

generating output signals conveying information related to vehicle events with one or more sensors of the vehicle event recording system;

effectuating storage of the consecutively acquired frames of visual information in a buffer memory of the vehicle event recording system;

facilitating interleaved overwriting of less valuable individual frames of the consecutively acquired frames of visual information stored in the buffer memory with additional frames acquired by the video camera, wherein value of individual frames of the consecutively acquired frames decreases:

i. with increasing time away from a time of a given vehicle event, and

ii. with presence of one or more adjacent frames in the consecutively acquired frames that convey substantially similar visual information;

detecting the given vehicle events based on the output signals; and

responsive to detecting the a given vehicle event, transferring the frames of visual information stored in the buffer memory to a long term storage memory of the vehicle event recording system, the transferred frames of visual information including frames of visual information for a period of time that begins before the given vehicle event and lasts until after the given vehicle event.

12. The method of claim 11 , wherein the less valuable individual frames of the consecutively acquired frames are not the oldest frames stored in the buffer memory.

13. The method of claim 11 , further comprising assigning individual value scores to the consecutively acquired frames of visual information stored in the buffer memory, adjusting the individual value scores based on an individual frame's age, and facilitating interleaved overwriting of the additional frames acquired by the video camera based on the adjusted individual value scores.

14. The method of claim 13 , wherein every n-th frame of the consecutively acquired frames of visual information, where n is an integer, is assigned a higher score than frames that immediately preceding and immediately following the n-th frame, which results in a first portion of the frames of visual information stored in the buffer memory having a first higher frame storage rate and a second portion of the frames of visual information stored in the buffer memory having a second lower frame storage rate that is less than or equal to the first higher frame rate divided by n.

15. The method of claim 14 , wherein the second storage density has a variable frame storage rate that corresponds to one or more of the proximity in time to the time of the given vehicle event, a distance travelled by the vehicle, a speed of the vehicle, a pixel difference between consecutively acquired frames of visual information, or a geographic location of the vehicle.

16. The method of claim 11 , wherein individual value scores are assigned to individual frames of visual information stored in the buffer memory based on a pixel difference between consecutive individual frames acquired by the video camera such that a second individual additional frame that consecutively follows a first individual additional frame and has a low pixel difference relative to the first individual additional frame is assigned a low value score and a third individual additional frame that consecutively follows the first individual additional frame and has a high pixel difference relative to the first individual additional frame is assigned a high value score.

17. The method of claim 11 , wherein individual value scores are assigned to individual frames of visual information stored in the buffer memory based on one or more of whether the vehicle was moving when the video camera acquired the individual frames of visual information, whether an operator was present in the vehicle when the video camera acquired the individual frames of information, a distance travelled by the vehicle, a speed of the vehicle, or a geographic location of the vehicle.

18. The method of claim 11 , further comprising facilitating the transfer of the frames of visual information from the buffer memory, responsive to the detection of the given vehicle event, at a transfer rate that exceeds a rate at which the frames of visual information are acquired by the video camera.

19. The method of claim 18 , wherein the transfer starts immediately after the detection of the given vehicle event rather than waiting for all video frames associated with the given vehicle event to be stored in the buffer memory.

20. The method of claim 18 , further comprising, responsive to detection of a second vehicle event in time proximity to the given vehicle event, dynamically extending a duration of the period of time that begins before the given vehicle event and lasts until after the second vehicle event such that the transferred frames of visual information include frames of visual information for an extended period of time that begins before the given vehicle event and lasts until after the second vehicle event.