Hyperspectral Imaging with Adjustable Multi-Passband Filter

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Solution Overview

Problem

Existing hyperspectral imaging technologies are costly, complex, and not easily adaptable to different spectral wavelength ranges, limiting their compatibility with compact-sized image sensors and requiring complex manufacturing processes.

Innovation Solution

A hyperspectral imaging arrangement using an array of LEDs with varying wavelengths, combined with adjustable multi-passband filters, such as Fabry-Perot interferometers, and an RGB or monochromatic image sensor, allowing for continuous wavelength adjustment and compatibility with small pixel image sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pixelized multispectral filters are permanently on top of pixels, then spectral filtering is achieved, but the minimum pixel size is limited and manufacturing complexity increases

Engineering Contradiction:
Improvespectral filtering capabilityVSAvoidminimum pixel size
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The pixelized filter is divided into multiple independently controllable regions (first pixelized filter layer and second pixelized filter layer), each capable of selecting different spectral bands. This segmentation allows the system to achieve hyperspectral imaging functionality without requiring each pixel to have a fixed filter, thereby enabling smaller pixel sizes while maintaining spectral filtering capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamically controllable pixelized filters that can change their spectral filtering properties in real-time through electrical control signals. The first and second pixelized filter layers can be independently activated or deactivated, allowing dynamic selection of spectral bands and enabling continuous wavelength adjustment without physical filter wheel movement.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If a filter wheel with fixed number of filters is used, then spectral selection is possible, but continuous wavelength adjustment is not possible and device complexity increases

Engineering Contradiction:
Improvespectral selection capabilityVSAvoidmechanical filter wheel structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical filter wheel system with an electronically controlled pixelized filter array. Instead of physically rotating a wheel to select filters, the system uses electronic control to activate specific regions of the pixelized filter layers, eliminating mechanical moving parts and enabling continuous, rapid wavelength adjustment without mechanical complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The pixelized filter layers serve multiple functions: they can be used individually or in combination, can select different spectral bands by activating different regions, and can work with both reflected and transmitted light modes. This multi-functionality replaces the need for multiple separate filters on a mechanical wheel.

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

3Measurement precision

If conventional hyperspectral imaging arrangements are used, then spectral imaging is achieved, but cost effectiveness decreases and adaptability to different spectral wavelength ranges is limited

Engineering Contradiction:
Improvehyperspectral imaging capabilityVSAvoidadaptability to different spectral wavelength ranges
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent enables continuous adjustment of spectral wavelength ranges by controlling which regions of the pixelized filter layers are activated. By changing the control signals to different pixel regions with different spectral characteristics, the system can adapt to various wavelength ranges without physical reconfiguration, achieving both cost-effectiveness and spectral adaptability.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If pixelized multispectral filters are used with compact-sized image sensors, then spectral filtering is achieved, but the size of the pixelized filter limits the minimum pixel size

Engineering Contradiction:
Improvespectral filtering capabilityVSAvoidpixel area
Core Design Contradiction:
Measurement precisionVSArea of moving object

Solution Approach 1:

By segmenting the filter functionality into multiple independently controllable pixel regions across two filter layers, the system achieves spectral filtering at the pixel level without requiring large filter structures. Each pixel can be assigned to control specific spectral bands through the segmented filter regions, enabling compact sensor design with smaller pixel sizes.

Inventive Principle:
Principle #1Segmentation

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 the creation of cost-effective, high-performance hyperspectral imaging capable of functioning with mobile device cameras, providing sufficient spectral bands in ambient light and enabling the use of small pixel image sensors.

Implementation Method 1

The adjustable multi passband filter may be a Fabry-Perot interferometer

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

Implementation Method 2

The adjustable multi passband filter may be a Fabry-Perot interferometer

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

the adjustable multi passband filter comprises a spectral filter which is adjustable by tilting the spectral filter at different angles to an incident light

Methodology Applied
Scientific EffectTilting spectral filter: Refraction

Data Source

PatentEP3427023B1Hyperspectral imaging arrangement
Publication Date: 2024.11.20 TEKNOLOGIAN TUTKIMUSKESKUS VTT OY
  • EP3427023B1 patent drawingFigure 1a
  • EP3427023B1 patent drawingFigure 1b
  • EP3427023B1 patent drawingFigure 2a

AI summary

An arrangement for hyperspectral imaging, comprising an imaging sensor (170,270); a band-pass filter element (130,230): at least one imaging optics element (120,160,220,260) configured to form an image on the imaging sensor (170,270); and a first adjustable multi passband filter (150a,255); wherein the first (150a,255) adjustable multi passband filter is configured to be adjusted by tilting.