Interference Imaging for 3D Refractive Index Tomography in Scattering Tissue
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Solution Overview
Problem
Conventional optical diffraction tomography (ODT) struggles to perform three-dimensional refractive index tomography on multiple scattering objects like three-dimensional cell tissues due to the overwhelming influence of multiple scattered light, which causes speckle generation and deteriorates the single-to-multi scattering ratio (SMR), making it difficult to extract structural information.
Innovation Solution
An observation apparatus and method that includes interference intensity image acquisition, complex amplitude image generation, and two-dimensional phase image generation, utilizing spatially and temporally coherent light sources, and techniques like Fourier fringe analysis and phase shift methods to selectively detect single scattered light, reducing the influence of multiple scattered light through processes such as collective accumulation of single scattering (CASS) and complex differential interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ODT is applied to multiple scattering objects, then three-dimensional refractive index tomography is attempted, but multiple scattered light causes speckle generation and deteriorates image quality
Solution Approach 1:
The patent segments the scattered light into single scattered light and multiple scattered light components. By selectively processing only the single scattered light component (which contains useful structural information) and excluding the multiple scattered light component (which causes speckle and noise), the system achieves high-quality 3D refractive index tomography of multiple scattering objects without the harmful effects of multiple scattering
Solution Approach 2:
The patent extracts and isolates the single scattered light component from the total scattered light. Using spatial frequency domain analysis and directional filtering, the system separates the single scattered light (which provides structural information) from the multiple scattered light (which causes speckle), thereby eliminating the harmful factor while preserving the measurement precision
2Loss of information
If conventional ODT images multiple scattering objects, then three-dimensional structure is reconstructed, but single-to-multi scattering ratio deteriorates making structural information extraction difficult
Solution Approach 1:
The patent dynamically adjusts the processing strategy based on the scattering properties of the object. By analyzing the spatial frequency characteristics and directional distribution of scattered light, the system adaptively separates single and multiple scattered light components, optimizing the single-to-multi scattering ratio for accurate structural information extraction in real-time
Solution Approach 2:
The patent introduces spatial frequency domain analysis and directional filtering as intermediary processing steps. These intermediaries enable the system to distinguish between single and multiple scattered light components, thereby improving the single-to-multi scattering ratio and facilitating accurate extraction of structural information from multiple scattering objects
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 three-dimensional refractive index tomography with reduced multiple scattered light influence, suppressing speckles and improving the single-to-multi scattering ratio (SMR), allowing for clearer structural analysis of multiple scattering objects.
Implementation Method 1
Light scattering refers to a phenomenon in which light interacts with an object to change a traveling direction of the light. In particular, when spatial non-uniformity of a refractive index in the object increases, the light interacts with the object many times in passing through the object.
Implementation Method 2
an interference intensity image at a reference position generated by interference between light irradiating an observation object along each of the plurality of light irradiation directions and passed through the observation object and reference light
Data Source
AI summary
An observation apparatus includes a light source, a mirror, a condenser lens, an objective lens, a beam splitter, an imaging unit, and an analysis unit. The analysis unit includes an interference intensity image acquisition unit, a first complex amplitude image generation unit, a second complex amplitude image generation unit, a two-dimensional phase image generation unit, a three-dimensional phase image generation unit, and a refractive index distribution calculation unit. The analysis unit irradiates an observation object with light along each of a plurality of light irradiation directions, acquires an interference intensity image at a reference position for each of the plurality of light irradiation directions from the imaging unit, and performs necessary processing based on the interference intensity images to obtain a three-dimensional refractive index distribution of the observation object.