Ladar system with adaptive receiver
Disclosed herein are various embodiments for a ladar system that includes an adaptive ladar receiver whereby the active pixels in a photodetector array used for reception of ladar pulse returns can be adaptively controlled based at least in part on where the ladar pulses were targeted by the ladar transmitter.
1. A ladar system comprising:
a ladar transmitter that includes a beam scanner, wherein the beam scanner selectively targets a plurality of range points within a frame, and wherein the ladar transmitter transmits ladar pulses toward the selectively targeted range points in accordance with a shot list; and
a ladar receiver that includes a photodetector array and a circuit;
wherein the photodetector array comprises a plurality of light sensors, wherein each light sensor (1) senses light that is indicative of a plurality of ladar pulse returns from a plurality of the range points and (2) generates a signal indicative of the sensed light;
wherein the circuit selectively defines a plurality of subsets of the light sensors for read out at a given time based on the shot list to produce a signal representative of the sensed light signals from the light sensors included within the defined subsets, the produced signal for use in computing range information with respect to the targeted range points; and
wherein the circuit includes feedback circuitry that amplifies outputs from the light sensors in a controlled feedback loop.
2. The system of claim 1 wherein the beam scanner selectively targets the range points by dynamically scanning a mirror according to the shot list.
3. The system of claim 2 wherein the beam scanner comprises a first mirror and a second mirror, wherein the first mirror is scannable to a plurality of first mirror scan positions, wherein the second mirror is scannable to a plurality of second mirror scan positions, wherein the first and second mirror scan positions in combination define where the ladar transmitter is targeted, and wherein the beam scanner employs compressive sensing to selectively target a subset of range points in the frame based on a range point down selection algorithm that identifies a subset of range points in the frame for targeting with ladar pulses.
4. The system of claim 2 wherein the beam scanner comprises a first mirror and a second mirror, wherein the first mirror is scannable to a plurality of first mirror scan positions based on a first control signal, wherein the second mirror is scannable to a plurality of second mirror scan positions based on a second control signal, wherein the first control signal scans the first mirror in a resonant mode, wherein the second control signal scans the second mirror in a point-to-point mode that varies as a function of the shot list, and wherein the first and second mirror scan positions in combination define where the ladar transmitter is targeted.
5. The system of claim 1 wherein the circuit includes a multiplexer that controls which light sensors are included in the defined subsets based on a control signal, wherein the control signal varies based on the shot list.
6. The system of claim 5 wherein the feedback circuitry includes amplifiers that are operatively between the photodetector array and the multiplexer.
7. The system of claim 6 wherein the photodetector array is resident on a substrate, and wherein the amplifiers are embedded in the substrate.
8. The system of claim 5 wherein the feedback circuitry serves as a matching network in resonance with a received ladar pulse return.
9. The system of claim 8 wherein the matching network is present on all input lines to the multiplexer.
10. The system of claim 1 wherein the light sensors correspond to pixels, and wherein the circuit selectively defines the subsets based on a mapping relationship between the pixels and range point locations that are targeted for ladar pulse shots by the shot list.
11. The system of claim 1 wherein the feedback circuitry serves as a matching network in resonance with a received ladar pulse return.
12. The system of claim 1 wherein the feedback circuitry is reset at each ladar pulse shot.
13. The system of claim 1 wherein the light sensors of the photodetector array correspond to a plurality of pixels, and wherein the defined subsets of light sensors change over time with respect to how many pixels are included in the defined subsets.
14. The system of claim 1 wherein the light sensors of the photodetector array correspond to a plurality of pixels, and wherein the circuit selectively controls which pixels are eligible for inclusion in the defined subsets based on feedback with respect to prior frames.
15. The system of claim 1 wherein the ladar transmitter transmits a plurality ladar pulses that exhibit a Gaussian pulse shape.
16. A ladar system comprising:
a ladar transmitter that includes a beam scanner, wherein the beam scanner selectively targets a plurality of range points within a frame, and wherein the ladar transmitter transmits ladar pulses toward the selectively targeted range points in accordance with a shot list; and
a ladar receiver that includes a photodetector array, a multiplexer, and a feedback circuit;
wherein the photodetector array comprises a plurality of light sensors, wherein each light sensor (1) senses light that is indicative of a plurality of ladar pulse returns from a plurality of the range points and (2) generates a signal indicative of the sensed light;
wherein the multiplexer selectively defines a plurality of subsets of the light sensors for read out at a given time in response to a control signal that varies based on the shot list to produce a signal representative of the sensed light signals from the light sensors included within the defined subsets, the produced signal for use in computing range information with respect to the targeted range points;
wherein the feedback circuit amplifies outputs from the light sensors in a controlled feedback loop; and
wherein the multiplexer receives the amplified outputs from the light sensors.
17. A ladar system comprising:
a ladar transmitter that selectively targets a plurality of range points within a frame in accordance with a shot list; and
a ladar receiver that includes a photodetector array and a circuit;
wherein the photodetector array comprises a plurality of light sensors, wherein each light sensor (1) corresponds to a pixel, (2) senses light that is indicative of a plurality of ladar pulse returns from a plurality of the range points, and (3) generates a signal indicative of the sensed light;
wherein the circuit selectively defines a plurality of subsets of the light sensors for read out at a given time based on the shot list to produce a signal representative of the sensed light signals from the light sensors included within the defined subsets, the produced signal for use in computing range information with respect to the targeted range points; and
wherein the circuit selectively controls which pixels are eligible for inclusion in the defined subsets based on feedback with respect to prior frames.
18. The system of claim 17 wherein the ladar transmitter includes a beam scanner that selectively targets the range points by dynamically scanning a mirror according to the shot list.
19. The system of claim 18 wherein the beam scanner comprises a first mirror and a second mirror, wherein the first mirror is scannable to a plurality of first mirror scan positions, wherein the second mirror is scannable to a plurality of second mirror scan positions, wherein the first and second mirror scan positions in combination define where the ladar transmitter is targeted, and wherein the beam scanner employs compressive sensing to selectively target a subset of range points in the frame based on a range point down selection algorithm that identifies a subset of range points in the frame for targeting with ladar pulses.
20. The system of claim 18 wherein the beam scanner comprises a first mirror and a second mirror, wherein the first mirror is scannable to a plurality of first mirror scan positions based on a first control signal, wherein the second mirror is scannable to a plurality of second mirror scan positions based on a second control signal, wherein the first control signal scans the first mirror in a resonant mode, wherein the second control signal scans the second mirror in a point-to-point mode that varies as a function of the shot list, and wherein the first and second mirror scan positions in combination define where the ladar transmitter is targeted.
21. The system of claim 17 wherein the circuit generates an adaptive fault tolerance mask that adjusts which of the pixels are eligible for inclusion in the defined subsets based on feedback from prior frames that indicates whether any of the pixels are malfunctioning.
22. The system of claim 17 wherein the circuit generates an adaptive mask that controls dynamic range for the produced signal by adjusting how many pixels are to be included in the defined subsets based on feedback from prior frames.
23. The system of claim 17 wherein the circuit generates an adaptive mask that adjusts which of the pixels are eligible for inclusion in the defined subsets based on feedback from prior frames that indicates a presence of interfering light that would impact one or more of the pixels.
24. The system of claim 17 wherein the circuit generates an adaptive mask that adjusts which of the pixels are eligible for inclusion in the defined subsets based on feedback from prior frames that indicates a presence of a scattering object that would impact one or more of the pixels.
25. The system of claim 17 wherein the circuit adjusts timing for ladar pulse shots on the shot list based on feedback from prior frames to reduce interference on the pixels of the defined sub sets.
26. The system of claim 17 wherein the circuit adjusts shot energy for ladar pulse shots on the shot list based on feedback from prior frames.
27. The system of claim 17 wherein the circuit adds or removes ladar pulse shots to or from the shot list based on feedback from prior frames.
28. The system of claim 17 wherein the circuit generates an adaptive mask that removes a center pixel from the defined subsets to reduce saturation risk based on feedback from prior frames.
29. The system of claim 17 wherein the feedback from prior frames comprises data derived from prior ladar pulse returns.
30. The system of claim 17 wherein the prior frames comprise video frames.