Spectral Image Sensor Unit with Periodic Filter Pattern
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Solution Overview
Problem
Current spectral imaging technologies face challenges in achieving compact, cost-effective, and accurate multispectral or hyperspectral imaging due to size constraints, light loss, and parallax errors, especially when imaging moving objects or scenes with three-dimensional structures, leading to significant distortions in spectral data.
Innovation Solution
A spectral image sensor unit with a periodically repeated filter pattern across the photodetector array allows for multiple sampling of spectral components at different angles, reducing parallax errors by averaging readings, and enabling simultaneous spectral and conventional imaging using a single objective lens and image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate imagers are used for spectral imaging and conventional imaging, then spectral information and spatial information can be captured independently, but the system size and weight increase significantly
Solution Approach 1:
The patent combines spectral imaging and conventional imaging functions into a single imager by integrating a spectral dimension (through filters or dispersive elements) with the conventional two-dimensional detector array. This merging eliminates the need for separate imagers, reducing system weight and complexity while maintaining both spectral and spatial imaging capabilities through a unified optical path and detector system.
Solution Approach 2:
The imager is designed to perform multiple functions simultaneously: it captures conventional two-dimensional spatial images and spectral information across multiple bands using the same optical system and detector array. The spectral dimension is added to the existing spatial dimensions, enabling the single device to function as both a conventional imager and a spectral imager, thereby achieving multi-functionality without increasing system weight.
2Measurement precision
If spectral imaging subdivides light into multiple spectral channels, then spectral information is obtained, but optical throughput decreases and signal to noise ratio deteriorates
Solution Approach 1:
The patent segments the spectral information capture across multiple detector elements or regions within the same detector array, rather than using separate optical paths for each spectral band. By dividing the detector array into multiple spectral channels (e.g., through filter arrays or spatially resolved spectroscopy), the system captures multiple spectral bands simultaneously through a single optical path, minimizing light loss while achieving spectral separation.
Solution Approach 2:
The imaging system captures all spectral bands continuously and simultaneously through the same optical path without sequential scanning or beam splitting that would cause light loss. The continuous optical path maintains high throughput while the detector array simultaneously records multiple spectral channels, ensuring no interruption or loss of light energy during spectral measurement.
3Measurement precision
If filters are placed in front of photodetector elements for spectral sampling, then spectral bands can be distinguished, but a large fraction of light is lost in each filter
Solution Approach 1:
The patent applies filtering selectively to specific regions or elements of the detector array rather than placing filters in the entire optical path. By localizing filters to only those detector elements that require spectral discrimination, the system achieves spectral band discrimination where needed while leaving other portions of the optical path filter-free, thereby minimizing overall light loss while maintaining spectral discrimination capability.
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 approach results in more accurate spectral imaging with reduced distortions, allowing for compact, cost-effective deployment on smaller platforms like unmanned aircraft, while maintaining the ability to perform conventional imaging and estimating three-dimensional scene structure.
Implementation Method 1
Each element comprises a filter or other means of adapting the spectral response of the element
Implementation Method 2
at least two sets of light sensor elements, where each element comprises a filter or other means of adapting the spectral response of the element
Data Source
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AI summary
An imager contains an image sensor with laterally varying spectral response. The imager is scanned over a scene or object to form a spectral image. The spectral responses are repeated at different positions in the field of view so as to reduce the effect of scene nonidealities, such as angle dependence or temporal variation, on the spectral image data. A part of the image sensor may be used for conventional two- dimensional imaging. This part of the image sensor may be used to estimate the scene geometry and scan movement, enabling further improvement in the spectral integrity.