Ladar Transmitter with Induced Phase Drift for Improved Gaze on Scan Area Portions

Abstract

Disclosed herein is a scanning ladar transmitter that employs an optical field splitter / inverter to improve the gaze characteristics of the ladar transmitter on desirable portions of a scan area. Also disclosed is the use of scan patterns such as Lissajous scan patterns for a scanning ladar transmitter where a phase drift is induced into the scanning to improve the gaze characteristics of the ladar transmitter on desirable portions of the scan area.

Description

CROSS-REFERENCE AND PRIORITY CLAIM TO RELATED PATENT APPLICATIONS[0001]This patent application claims priority to U.S. provisional patent application 62 / 297,126, filed Feb. 18, 2016 and entitled “Improved Ladar Transmitter with Resonant Scan Optical Field Splitter / Inverter”, the entire disclosure of which is incorporated herein by reference.[0002]This patent application also claims priority to U.S. provisional patent application 62 / 439,378, filed Dec. 27, 2016 and entitled “Ladar Transmitter with Improved Gaze on Scan Area Portions”, the entire disclosure of which is incorporated herein by reference.[0003]This patent application is related to U.S. patent application Ser. No. ______, filed this same day and entitled “Ladar Transmitter with Optical Field Splitter / Inverter for Improved Gaze on Scan Area Portions” (said application being identified by Thompson Coburn attorney docket number 56976-163577), the entire disclosure of which is incorporated herein by reference.INTRODUCTION[000...

AI Technical Summary

Benefits of technology

The patent discusses a problem faced by ladar systems in automotive applications. These systems have a large number of beam choices, which can result in slow speeds in environments with many interrogation cells. The inventors propose a solution using a field splitter / inverter and induced periodic phase drift to improve the gaze of the ladar transmitter. This can reduce the disadvantages of resonant mirror-based ladar while maintaining its acuity and specificity. The patent also mentions that use of high-speed scans like Lissajous scans can further improve gaze.

Problems solved by technology

However, conventional ladar solutions for computer vision problems suffer from high cost, large size, large weight, and large power requirements as well as large data bandwidth use.

These complicating factors have largely limited their effective use to costly applications that require only short ranges of vision, narrow fields-of-view and / or slow revisit rates.

However, these conventional systems are believed to suffer from a number of shortcomings.

For example, flash ladar systems require a very high energy per pulse laser, which is not only costly but can also be an eye hazard.

Furthermore, the read-out integrated circuits for flash ladar systems are typically quite noisy.

Also, the wide field-of-view signal-to-noise ratio (SNR) for flash ladar systems is typically very low, which results in short ranges, thereby detracting from their usefulness.

While radars have been highly optimized with scheduling methods to dwell (gaze) where gaze is needed when gaze is needed, conventional ladar systems today do not share this dwell optimality.

Design approach (i) is precise and adaptable but is extremely slow in environments where there are large numbers of interrogation cells present.

Design approach (ii) has historically been non-adaptable.

Images