Memory management in event recording systems
First Claim
Patent Images
1. ) Vehicle event recorders comprising. a camera;
- a managed loop buffer memory; and
an overwrite mechanism, said camera is operable for converting optical images to electronic signals suitable for recording in said managed loop buffer memory, said managed loop buffer memory is a random access, re-writ able, electronic storage medium of finite size suitable for storing data, and in particular data arranged as discrete video frame data, said overwrite mechanism electronically coupled to said managed loop buffer memory and arranged to manage data overwrite operations whereby a first video frame older than a second video frame is saved in the memory while the second frame is overwritten.
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Abstract
In vehicle event recorders which capture video as discrete image frames, a managed loop memory and management system is provided to realize a virtual ‘timeline dilation’ effect. For a buffer memory of limited size, the maximum extent of a video series in time is extended by trading a reduction in temporal resolution for an increase in temporal range. Memory cells are overwritten in an ‘interleaved’ fashion to effect a reduced frame rate for certain periods in relation to an event moment. In time periods furthest from the event moment, an effective frame rate is minimized while at time periods closest to the event moment, an effective frame rate is maximized.
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Citations
18 Claims
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1. ) Vehicle event recorders comprising.
a camera; - a managed loop buffer memory; and
an overwrite mechanism,said camera is operable for converting optical images to electronic signals suitable for recording in said managed loop buffer memory, said managed loop buffer memory is a random access, re-writ able, electronic storage medium of finite size suitable for storing data, and in particular data arranged as discrete video frame data, said overwrite mechanism electronically coupled to said managed loop buffer memory and arranged to manage data overwrite operations whereby a first video frame older than a second video frame is saved in the memory while the second frame is overwritten. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- a managed loop buffer memory; and
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13. ) Methods of dilating a timeline of a video series in a vehicle event recorder video managed loop buffer memory comprising the steps:
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receiving electronic signal data associated with video frames from a video camera; and
overwriting previously written data with newly received data, whereby previously written data is comprised of that belonging to a frame which is not the oldest frame in memory. - View Dependent Claims (14, 15, 16)
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17. ) In a vehicle event recorder system, a managed loop memory comprising:
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a coupling to a video camera output whereby images from the camera are received at said managed loop memory;
a plurality of memory cells each being associated with a single video frame;
an overwrite pointer associated with precisely one memory cell; and
a timeline definition, whereby said timeline definition directs the overwrite pointer to be associated with a cell which no longer remains a member of the timeline definition thus subjecting that cell to an impending overwrite action. - View Dependent Claims (18)
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Specification