Interference Fringe Imaging for Unstained Cell Focus and Contrast
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Solution Overview
Problem
Imaging unstained, live cells is challenging due to poor contrast between cell boundaries and background, making accurate cell parameter measurement difficult, and existing optical techniques increase complexity and cost.
Innovation Solution
Trans-illumination imaging system using interference fringes to enhance contrast and find focus by reducing light coherence with a diffuser, forming attenuated interference fringes, and employing automated focusing based on transformed images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If staining is used to improve cell detection, then image quality is improved, but cell viability is lost
Solution Approach 1:
The patent uses phase shift changes rather than color/stain changes to achieve contrast. By controlling the optical path difference through focus adjustment, the system creates detectable interference patterns without requiring any chemical staining, thus maintaining cell viability while enabling accurate cell detection and measurement.
Solution Approach 2:
The patent replaces chemical staining mechanisms with optical interference mechanisms. Instead of using chemical dyes to create contrast, the system uses controlled defocus to create interference fringes that provide contrast based on optical path differences, eliminating the need for cell fixation and staining.
2Reliability
If unstained cells are imaged directly, then cell viability is maintained, but image contrast is poor
Solution Approach 1:
The patent uses dynamic focus adjustment to create optimal interference conditions. By programmatically controlling the focus position to specific defocus values, the system dynamically creates interference fringes that enhance cell boundary visibility while maintaining cell viability, allowing accurate measurement without staining.
Solution Approach 2:
The patent changes the optical parameter of focus position from its conventional sharp-focus setting to a controlled defocused state. This parameter change creates interference fringes that enhance contrast for unstained cells, enabling accurate cell boundary detection while maintaining cell viability and avoiding staining requirements.
3Measurement precision
If phase contrast or differential interference contrast is used to improve contrast, then cell visibility is improved, but system complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the complex optical components required for phase contrast and differential interference contrast systems. By using a standard bright-field microscope with programmable focus control, the system achieves enhanced contrast through software-controlled defocus and interference fringe analysis, removing the need for specialized optical elements like phase plates, Wollaston prisms, or Nomarski optics.
Solution Approach 2:
The patent replaces complex mechanical/optical interference mechanisms with a simpler focus-adjustment mechanism. Instead of using differential interference contrast optics that require precise mechanical alignment of multiple optical components, the system uses programmable focus control to create interference patterns, simplifying the optical design while achieving similar or superior contrast enhancement.
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
Provides sharper images of unstained, living cells with accurate cell parameter measurement, economical optical design, and automated focusing.
Implementation Method 1
A coherence of light may be reduced upstream of a sample by scattering and mixing at least a portion of the light
Implementation Method 2
Image detection is performed with the sample sufficiently defocused to form interference fringes in the image
Data Source
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AI summary
The present invention provides a method of focusing an imaging system (80), the method comprising: detecting (204) one or more images of a sample (54), wherein the image contains interference fringes and is detected with an imaging detector (56); transforming (206) each of the one or more images to a frequency domain; determining (208) one or more values from each transformed image; adjusting (210) a focus of the sample (54) on the imaging detector (56) based on the one or more values from each transformed image; and detecting an image of the sample at the adjusted focus.