Stray Light Suppression in Wide Field Optics via Structured Illumination
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Solution Overview
Problem
Wide field optics used in imaging biological specimens or materials face challenges with stray light, which reduces contrast and limits the usable intensity dynamic, especially in heterogeneous luminescing surfaces, leading to measurement errors and difficulties in distinguishing useful light from stray light, particularly in high-density biochips.
Innovation Solution
A method and arrangement that utilize structured illumination patterns with dark and bright regions, where the dark regions completely cover the object, allowing for the generation of a dark image and a bright image, which are then subtracted to suppress stray light without interpolation, using a position-resolving detector like a CCD-camera.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wide field optics are used for imaging heterogeneous luminescing surfaces, then the imaging coverage and field of view are improved, but stray light increases which reduces contrast and measurement precision
Solution Approach 1:
The patent divides the illumination into multiple structured patterns (e.g., striped patterns with alternating bright and dark regions) that sequentially illuminate different areas of the specimen. By segmenting the illumination field and combining multiple images, the system achieves wide field coverage while suppressing stray light through computational subtraction of background contributions from each segmented region.
2Measurement precision
If confocal laser scanners are used to suppress stray light, then measurement precision and contrast are improved, but device complexity and adjustment complexity increase
Solution Approach 1:
The patent replaces the complex mechanical scanning system of confocal microscopes with a stationary wide field optic combined with structured illumination patterns. Instead of mechanically scanning a focused beam and pinhole, the system uses programmable illumination patterns projected onto the entire field of view, with computational processing to achieve confocal-like stray light suppression, thereby eliminating movable components and complex alignment requirements.
3Measurement precision
If structured illumination patterns are used with multiple images, then stray light suppression is improved, but the number of detector recordings increases
Solution Approach 1:
The patent employs periodic structured illumination patterns (such as sinusoidal or striped patterns) that are projected sequentially across the field of view. By using a small number of phase-shifted or position-shifted patterns (typically 3-9 images), the system achieves effective stray light suppression through computational algorithms, balancing the trade-off between measurement precision and recording time by optimizing the number of patterns based on the specific application requirements.
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 effectively suppresses stray light, improving image contrast and reducing noise, allowing for more accurate radiometric measurements and fluorescence microscopy without the need for complex trigonometric computations or interpolation, thus enhancing the depth resolution and reducing measurement errors.
Implementation Method 1
a position-resolving detector for optical radiation... with suppression of stray light
Data Source
AI summary
A method images an object (4) by means of a wide field optic onto a position resolving detector (6) for optical radiation with suppression of stray light. In this method, the object (4) is illuminated in at least one object plane (3) with at least two illumination patterns (26, 27) and corresponding images are detected for each of the illumination patterns (26, 27). The illumination patterns (26, 27) each have bright regions (26; 33; 37) and dark regions (27) in the object plane (3). When there is a superposition of the illumination patterns (26, 27) in the optic plane (3), the object (4) is completely covered. A dark image of the object is determined from the detected images. A bright image of the object (4) is generated and the dark image is subtracted from the bright image.