3D Refractive Index Phantom for Holographic Tomography Calibration
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Solution Overview
Problem
Current methods for metrological evaluation of 3D quantitative phase imaging systems are inadequate due to errors introduced by artifacts such as the 'missing cone' in data representation, anisotropic resolution, and mapping errors of spatial frequencies. Existing solutions are insufficient for comprehensive characterization of measurement systems, particularly in biomedical applications.
Innovation Solution
A three-dimensional refractive index distribution standard is developed using two-photon polymerization technology, featuring regions with varying refractive indices and complex geometries, such as prisms, cylinders, and coaxial rings, designed to mimic biological structures and assess the resolution and accuracy of measurement systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If holographic tomography with limited angular range is used, then practical application in biomedical fields is enabled, but measurement precision deteriorates due to missing cone artifacts and anisotropic resolution
Solution Approach 1:
The patent creates a synthetic phantom object with known refractive index distribution that copies the essential structural features of biological specimens. This phantom serves as a reference model to evaluate and characterize the performance of holographic tomography systems, allowing quantification of reconstruction errors and resolution characteristics without requiring actual biological samples.
Solution Approach 2:
The patent systematically varies refractive index parameters (creating regions with different refractive indices) and geometric parameters (sizes, shapes, and arrangements of regions) in the phantom object. This enables comprehensive evaluation of how measurement precision changes with different structural complexities and refractive index contrasts, providing a thorough characterization of system performance limits.
2Measurement precision
If complex 3D structures with known refractive index distribution are created, then measurement precision can be evaluated, but manufacturing precision becomes challenging due to limitations in available manufacturing technologies
Solution Approach 1:
Instead of directly manufacturing complex biological structures, the patent creates simplified phantom objects that copy the essential refractive index distribution characteristics. These phantoms are designed to be manufacturable while still providing sufficient complexity to evaluate measurement system performance, bridging the gap between manufacturing capabilities and evaluation requirements.
Solution Approach 2:
The phantom object is divided into multiple distinct regions with different refractive indices, each representing specific structural elements. This segmentation allows independent control and verification of each region's refractive index and geometry, making the overall structure easier to manufacture while maintaining evaluation capability through the combination of segmented regions.
3Ease of manufacture
If simple calibration objects like microspheres are used, then ease of manufacture is improved, but measurement precision deteriorates due to insufficient complexity to simulate biological structures
Solution Approach 1:
The patent extends the simple sphere concept by creating composite phantom objects with multiple segmented regions of different refractive indices. This segmentation maintains manufacturability while introducing sufficient structural complexity to evaluate resolution, contrast, and reconstruction accuracy for biological applications, overcoming the limitations of simple calibration objects.
Solution Approach 2:
The phantom object uses composite structures combining regions with different refractive indices within a single manufacturable geometry. This composite approach allows the object to be created using standard manufacturing techniques while providing the multi-scale, multi-contrast features necessary for comprehensive characterization of holographic tomography systems for biological specimens.
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
The standard provides a comprehensive metrological evaluation of 3D quantitative phase imaging systems by allowing for the assessment of resolution, refractive index accuracy, and error analysis, thereby improving the reliability and accuracy of measurements in biomedical applications.
Implementation Method 1
The standard is made in a technology of two-photon polymerization
Implementation Method 2
irradiating said material with a focused laser beam in the vicinity of the focus of said beam
Data Source
AI summary
Refractive index distribution standard in the form of a three-dimensional object which contains in its volume a base medium and regions of variable size and distance with a refractive index other than that of the base medium, characterised in that the difference between the refractive index of said regions and the refractive index of the base medium is not greater than 0.04, at least one of the regions is a set of at least two prisms or cylinders or coaxial rings of variable size and distance, having a dimension in at least one direction similar to the resolving power of the measurement system under assessment and at least one of the regions is sphere-like or ellipsoid-like in shape.