Acousto-Optic Tunable Filter Multi-Spectral Imaging Reconstruction

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Solution Overview

Problem

Current multi-spectral imaging techniques using acousto-optic tunable filters face limitations in angular aperture, spectral resolution, and energy efficiency, particularly in achieving high performance across a wide range of wavelengths.

Innovation Solution

The method involves measuring light intensity using one- or two-dimensional pixelated sensors near the focal plane, calibrating binding functions for each point and wavelength, and using acousto-optical diffraction to reconstruct images by interpolating measurements across multiple pixels and frequencies, allowing for improved spectral resolution and energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct multi-spectral imaging techniques using AOTF are used, then spectral resolution is improved, but angular aperture is limited

Engineering Contradiction:
Improvespectral resolutionVSAvoidangular aperture
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent transitions from direct imaging to a reconstruction approach that treats the imaging problem in a higher-dimensional space (combining spatial coordinates X, Y with wavelength λ). By measuring intensity distributions at multiple acoustic frequencies and reconstructing the spectral cube, the system achieves both high spectral resolution and large angular aperture without the direct imaging limitations.

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

Solution Approach 2:

The patent changes the operating parameters by using multiple acoustic frequencies to probe different wavelength components. Instead of relying on a single frequency setting, the system varies the acoustic frequency parameter to extract spectral information, enabling simultaneous achievement of high spectral resolution and wide angular acceptance through computational reconstruction.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If direct multi-spectral imaging techniques using AOTF are used, then spectral resolution is improved, but energy efficiency deteriorates

Engineering Contradiction:
Improvespectral resolutionVSAvoidenergy efficiency
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by measuring intensity distributions at a limited number of strategically chosen acoustic frequencies rather than requiring continuous spectral scanning. The reconstruction algorithm then interpolates to obtain the complete spectral information, reducing the total energy required while maintaining high spectral resolution through intelligent sampling.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent creates a computational model (the spectral cube) that copies and reconstructs the full spectral information from a reduced set of measurements. By using the binding functions to map measured intensity distributions to the complete spectral data, the system avoids the energy cost of direct full-spectrum imaging while preserving spectral resolution.

Inventive Principle:
Principle #26Copying

3Loss of information

If a series of images for a series of determined frequencies is acquired, then spectral information is obtained, but acquisition time increases

Engineering Contradiction:
Improvespectral informationVSAvoidacquisition time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent performs preliminary calibration to establish binding functions that relate acoustic frequency, spatial position, and wavelength. This preliminary action creates a mathematical framework that allows rapid reconstruction of spectral information from minimal measurements, significantly reducing acquisition time compared to traditional sequential imaging methods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical/sequential imaging process with a computational reconstruction system. Instead of physically scanning through all wavelengths and capturing separate images, the system uses acoustic frequency modulation combined with mathematical reconstruction algorithms to extract spectral information simultaneously, dramatically reducing measurement time.

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

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 multi-spectral imaging with increased angular aperture, high spectral resolution, and reduced energy requirements, effectively overcoming the limitations of existing methods by applying advanced calibration and reconstruction techniques.

Implementation Method 1

a secondary optical source obtained by acousto-optical diffraction of the light, coming from a primary optical source

Methodology Applied
Scientific EffectAcousto-optical diffraction: Acousto-optic Effect

Implementation Method 2

measurements of the intensity of the light, in the vicinity of a focal plane of an optic, coming from a secondary optical source obtained by acousto-optical diffraction

Methodology Applied
Scientific EffectOptical diffraction: Diffraction

Data Source

PatentEP2839254B1Method and device for reconstructive multi-spectral imaging
Publication Date: 2021.06.30 FASTLITE
  • EP2839254B1 patent drawingFigure 1~2
  • EP2839254B1 patent drawingFigure 3
  • EP2839254B1 patent drawing

AI summary

Method and device for reconstructive multi-spectral imaging using a fixed or movable instrument, comprising: measuring the intensity of the light coming from a secondary optical source obtained by acousto-optic diffraction 2 of the light originating from a primary optical source 1; acquiring said measurements of the intensity of the light from said secondary optical source; calibrating, for a given acoustic frequency, two functions relating, for each point M on the primary source 1 and for each instant, an image point m in the focal plane 4 to said point M on the primary source 1, and relating, for each point m in the focal plane 4, and for each wavelength of said primary source 1, the acoustic frequency enabling said acousto-optic diffraction 2 to the point m in said focal plane 4, respectively; and obtaining the intensity of the image corresponding to the point M on the primary source 1 by measuring the signal detected by a pixel in the position m in the focal plane 4, at one instant and for a given acoustic frequency.