Time-dependent filtering for lidar signals

1. A method for estimating a distance of an object from a Light Detection and Ranging (LIDAR) system, comprising:

transmitting a first light signal towards the object using a LIDAR system;

detecting a second light signal by a light sensor to generate a detected signal, the second light signal comprising a reflection of the first light signal from the object;

generating a filtered signal by applying a time-dependent adjustable filter to the detected signal, wherein the time-dependent adjustable filter comprises at least a first cutoff frequency corresponding to a first time duration, and a second cutoff frequency corresponding to a second time duration, the first time duration corresponding to the time of transmission of the first light signal and a first time threshold, the second time duration corresponding to the time between the first time threshold and the second time threshold; and

estimating the distance of the object from the LIDAR system based at least on the filtered signal.

2. The method of claim 1 , wherein the time-dependent adjustable filter is a variable frequency low-pass filter.

3. The method of claim 1 , wherein the first cutoff frequency of the time-dependent adjustable filter is adjusted based on an elapsed time since transmission of the first light signal.

4. The method of claim 1 , wherein the second cutoff frequency of the time-dependent adjustable filter is adjusted based on an expected amount of spreading in the second light signal.

5. The method of claim 1 , wherein the first cutoff frequency is larger than the second cutoff frequency.

6. The method of claim 1 , wherein the time-dependent adjustable filter comprises at least two capacitors disposed in parallel, and one or more switches connected to the at least two capacitors.

7. An apparatus for estimating a distance of an object from a Light Detection and Ranging (LIDAR) system, comprising:

at least one processor configured to:

transmit a first light signal towards the object using a LIDAR system;

detect a second light signal by a light sensor to generate a detected signal, the second light signal comprising a reflection of the first light signal from the object;

generate a filtered signal by applying a time-dependent adjustable filter to the detected signal, wherein the time-dependent adjustable filter comprises at least a first cutoff frequency corresponding to a first time duration, and a second cutoff frequency corresponding to a second time duration, the first time duration corresponding to the time of transmission of the first light signal and a first time threshold, the second time duration corresponding to the time between the first time threshold and the second time threshold;

estimate the distance of the object from the LIDAR system based at least on the filtered signal; and

a memory coupled to the at least one processor.

8. The apparatus of claim 7 , wherein the time-dependent adjustable filter is a variable frequency low-pass filter.

9. The apparatus of claim 7 , wherein the first cutoff frequency of the time-dependent adjustable filter is adjusted based on an elapsed time since transmission of the first light signal.

10. The apparatus of claim 7 , wherein the second cutoff frequency of the time-dependent adjustable filter is adjusted based on an expected amount of spreading in the second light signal.

11. The apparatus of claim 7 , wherein the first cutoff frequency is larger than the second cutoff frequency.

12. The apparatus of claim 7 , wherein the time-dependent adjustable filter comprises at least two capacitors disposed in parallel, and one or more switches connected to the at least two capacitors.

13. An apparatus for estimating a distance of an object from a Light Detection and Ranging (LIDAR) system, comprising:

means for transmitting a first light signal towards the object using a LIDAR system;

means for detecting a second light signal by a light sensor to generate a detected signal, the second light signal comprising a reflection of the first light signal from the object;

means for generating a filtered signal by applying a time-dependent adjustable filter to the detected signal, wherein the time-dependent adjustable filter comprises at least a first cutoff frequency corresponding to a first time duration, and a second cutoff frequency corresponding to a second time duration, the first time duration corresponding to the time of transmission of the first light signal and a first time threshold, the second time duration corresponding to the time between the first time threshold and the second time threshold; and

means for estimating the distance of the object from the LIDAR system based at least on the filtered signal.

14. The apparatus of claim 13 , wherein the time-dependent adjustable filter is a variable frequency low-pass filter.

15. The apparatus of claim 13 , wherein the first cutoff frequency of the time-dependent adjustable filter is adjusted based on an elapsed time since transmission of the first light signal.

16. The apparatus of claim 13 , wherein the second cutoff frequency of the time-dependent adjustable filter is adjusted based on an expected amount of spreading in the second light signal.

17. The apparatus of claim 13 , wherein the first cutoff frequency is larger than the second cutoff frequency.

18. The apparatus of claim 13 , wherein the time-dependent adjustable filter comprises at least two capacitors disposed in parallel, and one or more switches connected to the at least two capacitors.

19. A non-transitory processor-readable medium for estimating a distance of an object from a Light Detection and Ranging (LIDAR) system, comprising processor-readable instructions configured to cause one or more processors to:

transmit a first light signal towards the object using a LIDAR system;

detect a second light signal by a light sensor to generate a detected signal, the second light signal comprising a reflection of the first light signal from the object;

generate a filtered signal by applying a time-dependent adjustable filter to the detected signal, wherein the time-dependent adjustable filter comprises at least a first cutoff frequency corresponding to a first time duration, and a second cutoff frequency corresponding to a second time duration, the first time duration corresponding to the time of transmission of the first light signal and a first time threshold, the second time duration corresponding to the time between the first time threshold and the second time threshold; and

estimate the distance of the object from the LIDAR system based at least on the filtered signal.

20. The non-transitory processor-readable medium of claim 19 , wherein the time-dependent adjustable filter is a variable frequency low-pass filter.

21. The non-transitory processor-readable medium of claim 19 , wherein the first cutoff frequency of the time-dependent adjustable filter is adjusted based on an elapsed time since transmission of the first light signal.

22. The non-transitory processor-readable medium of claim 19 , wherein the second cutoff frequency of the time-dependent adjustable filter is adjusted based on an expected amount of spreading in the second light signal.

23. The non-transitory processor-readable medium of claim 19 , wherein the first cutoff frequency is larger than the second cutoff frequency.

24. The non-transitory processor-readable medium of claim 19 , wherein the time-dependent adjustable filter comprises at least two capacitors disposed in parallel, and one or more switches connected to the at least two capacitors.