Imaging Polarimeter with DROIC for High-Speed Registration

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Solution Overview

Problem

Existing imaging polarimeter systems face inefficiencies such as reduced signal-to-noise ratio, aperture, and field of view, along with temporal and spatial registration issues, which hinder their effectiveness in capturing dynamic scenes and long-range mission operations.

Innovation Solution

The implementation of a polarimeter system that includes a dual photoelastic modulator and a digital read-out integrated circuit (DROIC) with multiple counter bins, allowing for high-speed polarization modulation and accurate temporal and spatial registration by separating and reading out photo-generated counts over an integration frame rate, enabling each pixel to operate as its own polarimeter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional imaging polarimeter systems are used, then polarization information can be acquired, but the signal-to-noise ratio is reduced and spatial resolution is compromised

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidspatial resolution

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The system divides the focal plane into multiple discrete pixels, with each pixel functioning as an independent polarimeter. This segmentation allows simultaneous measurement of polarization information across the entire field of view while maintaining high spatial resolution through the detailed pixel structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces mechanical rotating polarizer systems with a static pixel array where polarization measurement is achieved through electronic signal processing. This substitution eliminates mechanical limitations and improves both signal-to-noise ratio and spatial resolution by using digital readout of photo-generated counts from each pixel.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional polarimeter systems are used, then polarization data can be collected, but temporal registration issues occur in dynamic scenes

Engineering Contradiction:

Improvetemporal registrationVSAvoidcapture speed

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system continuously integrates photo-generated counts from each pixel throughout the entire exposure period, maintaining continuous measurement without interruption. This continuous action ensures accurate temporal registration in dynamic scenes while preserving high capture speed through parallel processing across all pixels.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

Each pixel autonomously performs polarization measurement independently, with no requirement for external synchronization or mechanical adjustment. This self-service capability enables accurate temporal registration in dynamic scenes while maintaining high productivity through simultaneous operation of all pixels.

Inventive Principle:

Principle #25Self-service

3Area of stationary object

If conventional imaging polarimeters are used, then polarization information can be obtained, but field of view and aperture are reduced

Engineering Contradiction:

Improvefield of viewVSAvoidpolarization measurement accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The system measures polarization information in the temporal dimension by integrating photo-generated counts over the exposure period, rather than requiring spatial separation of polarization components. This dimensional approach allows full polarization measurement across the entire field of view without reducing aperture or measurement accuracy.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances spatial and temporal registration, allowing for high-resolution imaging polarimetry with improved signal-to-noise ratio and the ability to capture dynamic scenes without impacting spatial resolution or field of view, facilitating accurate detection and identification of objects in various environments.

Implementation Method 1

a dual photoelastic modulator configured to modulate a polarization state of an incident beam at a high repetition frequency

Methodology Applied

Scientific EffectPhotoelasticity: Photoelasticity

Implementation Method 2

an optical sensor array configured to detect the intensity modulated beam

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS12163841B1Systems and methods of acquiring polarization information

Publication Date: 2024.12.10 GENERAL ATOMICS AERONAUTICAL SYSTEMS INC

AI summary

Some embodiments provide imaging polarimeter systems comprising: a polarization modulator system configured to modulate a polarization state of an incident beam at a repetition frequency, and outputting a polarized modulated beam; a polarizer positioned to produce an intensity modulated beam; and a detector system comprising: an optical sensor array; a digital read-out integrated circuit (DROIC); and a polarization state system; wherein the optical sensor array is optically aligned with at least a portion of the beam path such that the intensity modulated beam impinges on the sensor array; wherein the DROIC, for each pixel of the optical sensor array, is configured to separate, over time and within an integration frame rate, sets of photo-generated counts; and wherein the polarization state system is configured to identify a series of polarization states for each pixel based on the sets of photo-generated counts and according to the integration frame rate.