Coded Aperture Wavelength Filter Sets for Spectral Crosstalk Reduction
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Solution Overview
Problem
Current image detection systems, such as focal plane arrays, struggle to accurately distinguish and identify specific wavelengths of energy due to the limitations of broadband detector elements and the introduction of spectral crosstalk from color filters, making it costly and complex to detect certain wavelengths like infrared, especially for applications requiring precise energy identification.
Innovation Solution
Implementing a coded aperture with a plurality of wavelength filter sets arranged in a predetermined pattern to transmit energy in specific wavelength bands towards a detector array, allowing for the processing of sensor data to identify spatial locations of energy within each wavelength band without the need for multiple sensors or color filter arrays, using Fourier transforms to separate and filter energy within intensity spatial frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If color filters are used at the image plane to selectively transmit light of various frequencies, then wavelength discrimination capability is improved, but spectral crosstalk is introduced and manufacturing complexity increases
Solution Approach 1:
The coded aperture is divided into multiple wavelength filter sets, each set containing filters for different wavelength bands arranged in a predetermined pattern. This segmentation allows different wavelength components to be spatially separated and directed to different detector elements, achieving wavelength discrimination without the spectral crosstalk problems of conventional color filter arrays at the image plane.
2Measurement precision
If multiple focal plane arrays are used to detect different wavelength bands, then wavelength identification accuracy is improved, but device complexity and cost increase prohibitively
Solution Approach 1:
Multiple wavelength filter sets for different wavelength bands are merged into a single coded aperture structure. This allows a single detector array to receive and process signals from multiple wavelength bands simultaneously, achieving the functionality of multiple focal plane arrays while using only one detector, thereby reducing device complexity and cost.
Solution Approach 2:
The invention adds a spatial frequency dimension to wavelength discrimination. By arranging wavelength filter sets in a predetermined pattern and using Fourier transform processing, the system separates wavelength components in the spatial frequency domain, enabling multi-wavelength detection with a single detector array without requiring multiple physical detector layers.
3Device complexity
If broadband detector elements are used, then device simplicity is maintained, but the ability to distinguish particular wavelengths is lost
Solution Approach 1:
Wavelength filtering is performed preliminarily in the coded aperture before light reaches the detector. The wavelength filter sets in the coded aperture pre-separate different wavelength components and direct them to different spatial locations, so that the broadband detector elements can subsequently detect these pre-separated wavelength components without needing inherent wavelength discrimination capability themselves.
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
Enables accurate identification and spatial localization of energy within specific wavelength bands, reducing costs and complexity, and effectively distinguishing between different energy sources, such as missile launches, by generating wavelength band images that can be presented in a colorized format for human visibility.
Implementation Method 1
The coded aperture comprises a plurality of wavelength filter sets arranged in a predetermined pattern. Each wavelength filter set is configured to transmit energy in a corresponding wavelength band of a plurality of different wavelength bands.
Implementation Method 2
The detector array generates sensor data that quantifies energy received by each detector element.
Implementation Method 3
The sensor data is processed based on the predetermined pattern to identify spatial locations of energy in each corresponding wavelength band with respect to the scene.
Implementation Method 4
for each wavelength band of the plurality of different wavelength bands, a corresponding intensity spatial frequency range of a plurality of different intensity spatial frequency ranges based on the predetermined pattern is determined
Data Source
AI summary
Mechanisms for identifying energy received from a scene are provided. A coded aperture in an optical system receives energy from a scene. The coded aperture comprises a plurality of wavelength filter sets arranged in a predetermined pattern. Each wavelength filter set is configured to transmit energy in a corresponding wavelength band of a plurality of different wavelength bands. The coded aperture transmits the energy toward a detector array comprising a plurality of detector elements. The detector array generates sensor data that quantifies energy received by each detector element. The sensor data is processed based on the predetermined pattern to identify spatial locations of energy in each corresponding wavelength band with respect to the scene.