Coherent Light Observation for Multiple Scattering Imaging

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Solution Overview

Problem

Conventional two-beam interference methods for imaging require a laser light source with a single frequency and long coherence length, leading to instability due to environmental variations and difficulty in optical path adjustment, especially when observing multiple scattering objects.

Innovation Solution

An observation apparatus and method that generates and updates complex amplitude images across multiple focal planes and light irradiation directions, using spatial or intensity modulation to reduce the influence of multiple scattered light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a laser light source with long coherence length is used for two-beam interference imaging, then interference stability is improved, but device complexity and environmental sensitivity increase

Engineering Contradiction:
Improveinterference stabilityVSAvoidoptical path adjustment difficulty
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the reference light path from the traditional two-beam interference setup, using only object light that has passed through the sample. This eliminates the need for precise optical path matching between reference and object beams, reducing device complexity while maintaining imaging capability through digital reference removal algorithms

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/optical interference system with a computational approach. Instead of relying on physical interference patterns from matched optical paths, the system uses digital signal processing to remove reference light components, substituting mechanical precision requirements with algorithmic processing

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

2Measurement precision

If conventional two-beam interference method is used for multiple scattering objects, then imaging capability is improved, but scattered light influence increases

Engineering Contradiction:
Improveimaging capabilityVSAvoidscattered light influence
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful scattered light into useful information by capturing its temporal intensity fluctuations. The scattered light, previously considered noise, is now measured over multiple time points to extract autocorrelation functions, which reveal structural information about the sample while filtering out the harmful random scattering effects

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent performs preliminary temporal averaging and autocorrelation analysis on the scattered light signals before final image reconstruction. By pre-processing the raw data to extract statistical properties, the system prepares the information in a form that separates signal from noise, reducing scattered light influence in the final image

Inventive Principle:
Principle #10Preliminary action

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 stable and effective observation of multiple scattering objects by reducing the impact of scattered light, allowing for accurate three-dimensional imaging.

Implementation Method 1

light output from a light source is split into two light beams, one split light passed through the observation object is set as object light, the other split light without passing through the observation object is set as reference light, and an interference intensity image generated by interference between the object light and the reference light

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

using spatial or intensity modulation to reduce the influence of multiple scattered light

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Data Source

PatentEP4657135A1Observation device and observation method
Publication Date: 2025.12.03 HAMAMATSU PHOTONICS KK
  • EP4657135A1 patent drawingFigure 1
  • EP4657135A1 patent drawingFigure 2
  • EP4657135A1 patent drawingFigure 3

AI summary

An observation apparatus 1A includes a light source 10, an irradiation unit 31, an imaging unit 50, and a processing unit 60. The irradiation unit 31 inputs spatially coherent light output from the light source 10, generates first light and second light from the input light, and irradiates an observation object S with the first light and the second light in an overlapping manner. The irradiation unit 31 irradiates the observation object S with the first light along a fixed light irradiation direction, and irradiates the observation object S with the second light along each of a plurality of light irradiation directions. The imaging unit 50 receives both the first light and the second light, and captures an interference intensity image on each of a plurality of focal planes. The processing unit 60 performs required processing based on the interference intensity image to generate a complex amplitude image and the like. Thus, an observation apparatus capable of reducing influence of multiple scattered light and easily observing an observation object even in the case in which the observation object is a multiple scattering object is realized.