Adaptive control of ladar systems using spatial index of prior ladar return data

Abstract

Disclosed herein are examples of ladar systems and methods where data about a plurality of ladar returns from prior ladar pulse shots gets stored in a spatial index that associates ladar return data with corresponding locations in a coordinate space to which the ladar return data pertain. This spatial index can then be accessed by a processor to retrieve ladar return data for locations in the coordinate space that are near a range point to be targeted by the ladar system with a new ladar pulse shot. This nearby prior ladar return data can then be analyzed by the ladar system to help define a parameter value for use by the ladar system with respect to the new ladar pulse shot. Examples of such adaptively controlled parameter values can include shot energy, receiver parameters, shot selection, camera settings, and others.

Description

CROSS-REFERENCE AND PRIORITY CLAIM TO RELATED PATENT APPLICATION[0001]This patent application claims priority to U.S. provisional patent application Ser. No. 62 / 750,540, filed Oct. 25, 2018, and entitled “Adaptive Control of Ladar Systems Using Spatial Index of Prior Ladar Return Data”, the entire disclosure of which is incorporated herein by reference.[0002]This patent application also claims priority to U.S. provisional patent application Ser. No. 62 / 805,781, filed Feb. 14, 2019, and entitled “Adaptive Control of Ladar Systems Using Spatial Index of Prior Ladar Return Data”, the entire disclosure of which is incorporated herein by reference.[0003]This patent application is also related to (1) U.S. patent application Ser. No. ______ filed this same day, and entitled “Adaptive Control of Ladar Shot Energy Using Spatial Index of Prior Ladar Return Data” (said application being identified by Thompson Coburn Attorney Docket Number 56976-185809), (2) U.S. patent application Ser. No. ___...

AI Technical Summary

Benefits of technology

[0004]Safe autonomy in vehicles, whether airborne, ground, or sea-based, relies on rapid precision, characterization of, and rapid response to, dynamic obstacles. Ladar systems are commonly used for detecting such obstacles. As used herein, the term “ladar” refers to and encompasses any of laser radar, laser detection and ranging, and light detection and ranging (“lidar”).

[0007]Accordingly, in an example embodiment, the inventors disclose a ladar system that adapts shot energy for the ladar transmitter as a function of prior ladar return data so that the ladar system can achieve a more uniform illumination (or smoother illumination) of nearby parts of the field of view. Accordingly, the ladar transmitter may adjust its shot energy on a shot-by-shot basis for interrogating range points that are near each other in the field of view. It should be understood that the goal of increasing the uniformity or smoothness of illumination by the ladar transmitter over a region of nearby portions of the field of view does not require the ladar transmitter to produce equal illumination for each range point in that region. Instead, it should be understood that increased uniformity or smoothness is a soft term that relates to a gradient of intensities that is sufficiently mild so as to not unduly erode the performance of object classification algorithms (many of which may be powered by machine learning techniques, edge detection processes, bounding boxes, and others).

Problems solved by technology

However, it is sometimes the case that artifacts and noise may be present in the ladar return data and ladar images used for object detection with autonomous vehicles.

Such artifacts and noise can hamper the analysis operations that are performed on the ladar return data.

However, the presence of artifacts and noise in the ladar images can corrupt the training process and / or the classification process, which can lead to a risk of misclassification during vehicle operation.

The inventors believe that some of the artifacts and noise present in ladar return data arise from non-uniform illumination of the field of view by the ladar system.

Furthermore, a number of factors can make the goal of increasing the uniformity illumination technically challenging.

Because current lasers operate at a fast re-fire rate (e.g., 100,000 to 3,000,000 shots per second is typical), this means that using ladar return data to adapt the ladar system with low latency is a computationally-challenging task.

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