Fabry-Perot Filter Mosaic for Snapshot Hyperspectral Imaging

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Solution Overview

Problem

Current hyperspectral cameras face challenges in achieving high-speed data acquisition and efficient spectral imaging due to limited light throughput and the need for time-consuming spatial scanning, which results in large datasets and increased complexity and cost.

Innovation Solution

The integration of Fabry-Perot filters directly on the sensor array, allowing for simultaneous detection of different spectral bands with varying spatial resolution, and the use of an objective lens to project a single image onto the sensor array, enabling snapshot imaging and reducing cross-talk and alignment issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If line scanners or pushbroom systems are used to capture spectral bands, then spectral resolution is improved, but spatial scanning time increases and productivity decreases

Engineering Contradiction:
Improvespectral resolutionVSAvoiddata acquisition speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The sensor array is divided into multiple segments or regions, each capturing a different spectral band simultaneously. This segmentation allows parallel acquisition of multiple spectral bands without temporal scanning, resolving the contradiction between spectral resolution and acquisition speed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from temporal scanning (time dimension) to spatial multiplexing (adding a spectral dimension across the sensor array). Multiple spectral bands are captured across different spatial locations on the sensor array simultaneously, eliminating the need for time-consuming spatial scanning while maintaining spectral resolution.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If pixels are made smaller to improve spatial resolution, then spatial resolution is improved, but light throughput decreases and signal-to-noise ratio worsens

Engineering Contradiction:
Improvespatial resolutionVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

Multiple sensor elements or detector segments are combined to form a single effective pixel with increased light collection area. This merging maintains spatial resolution by preserving the individual element positions while improving signal-to-noise ratio through increased total light throughput to the detector.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple image copies are created for spectral detection, then spectral information is improved, but cross-talk between image copies increases

Engineering Contradiction:
Improvespectral informationVSAvoidcross-talk
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The harmful cross-talk effect is extracted and removed from the optical path through selective filtering. Optical filters are placed in front of specific sensor regions to block stray light from adjacent image copies, eliminating cross-talk while preserving the spectral information carried by the filtered light.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If Fabry-Perot filters are integrated on sensor elements, then spectral definition is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvespectral definitionVSAvoidintegration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A single Fabry-Perot filter structure is designed to perform multiple spectral filtering functions simultaneously. The filter is configured with multiple reflective layers that can selectively transmit different spectral bands, allowing one integrated component to replace what would otherwise require multiple separate filters, thereby reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables faster acquisition of 3D hyperspectral cubes with improved spectral definition and reduced complexity, allowing for more efficient data processing and lower costs while maintaining high spectral and spatial resolution.

Implementation Method 1

The mosaic has a corresponding cluster of filters of different bands integrated on one or more of the sensor elements so that the image can be detected simultaneously at the different bands

Methodology Applied
Scientific EffectFabry-Perot filtering: Fabry-Perot Interferometer

Implementation Method 2

having an objective lens for producing an image

Methodology Applied
Scientific EffectOptical focusing: Lens

Data Source

PatentEP2773929B1Spectral camera with mosaic of filters for each image pixel
Publication Date: 2023.12.13 INTERUNIVERSITAIR MICRO ELECTRONICS CENT (IMEC VZW)
  • EP2773929B1 patent drawingFigure 1
  • EP2773929B1 patent drawingFigure 2
  • EP2773929B1 patent drawingFigure 3

AI summary

A spectral camera for producing a spectral output has an objective lens (10) for producing an image, a mosaic of filters (30) for passing different bands of the optical spectrum, and a sensor array (40) arranged to detect pixels of the image at the different bands passed by the filters, wherein for each of the pixels, the sensor array has a cluster of sensor elements for detecting the different bands, and the mosaic has a corresponding cluster of filters of different bands, integrated on the sensor element so that the image can be detected simultaneously at the different bands. The filters are first order Fabry-Perot filters, which can give any desired passband to give high spectral definition. Cross talk can be reduced since there is no longer a parasitic cavity.