Method for automatically adapting a pattern projection rate in an active perception system

1 . A method for adjusting a pattern projection rate in an active perception system, the method comprising:

observing a scene with an event-based sensor array;

projecting a current light pattern of a sequence of light patterns on the scene for a given interval of time;

retrieving events generated by the event-based sensor array in response to the projection of the current light pattern;

monitoring event retrieval progress to determine an end-of-burst criterion in the events; and

dynamically triggering a projection of a next light pattern in the sequence of light patterns when the end-of-burst criterion is met.

2 . The method of claim 1 , comprising:

setting a counter with a value based on a number of generated events; and

decrementing the counter as the events are retrieved;

wherein the end-of-burst criterion is met when the value of the counter falls below a threshold (ThC).

3 . The method of claim 1 , comprising:

computing an event retrieval rate as the events are retrieved;

wherein the end-of-burst criterion is met when the event retrieval rate falls below a threshold (ThR).

4 . The method of claim 1 , wherein the end-of-burst criterion is met when no events are generated over a number of successive cycles of a system clock.

5 . The method of claim 1 , wherein monitoring of the event retrieval progress starts an amount of time after a beginning of the projection.

6 . The method of claim 1 , wherein the projection of the next light pattern occurs a fixed amount of time (Tm) after the end-of-burst criterion is met.

7 . The method of claim 2 , wherein the sensor array includes pixels organized in rows, the method comprising:

generating a request for each row in which at least one pixel generates an event;

setting the counter with a number of rows having generated a request; and

decrementing the counter by one each time all events of one row are retrieved.

8 . The method of claim 3 , wherein the event retrieval rate is computed as a sliding average over several retrieval cycles.

9 . The method of claim 2 , comprising:

delaying the event retrieval until the counter meets a stationary condition.

10 . A method for adjusting a pattern projection rate in an active perception system, the method comprising:

observing a scene with an event-based sensor array;

projecting a current light pattern of a sequence of light patterns on the scene for a given interval of time;

retrieving events generated by the event-based sensor array in response to the projection of the current light pattern;

monitoring event retrieval progress; and

dynamically stopping the projection of the current light pattern when the event retrieval meets a peak event generation criterion.