Microscope Image Fusion Using Variable Numerical Apertures

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Solution Overview

Problem

Conventional microscopes face a conflict between resolution and depth of field, and digital image acquisition methods fail to effectively combine images with different numerical apertures, limiting the sharpness and depth of field in microscopic images, especially when observing non-flat objects.

Innovation Solution

A method for acquiring and merging microscopic images with different resolutions and depths of focus by using a microscope system with adjustable numerical apertures, where at least two images are captured at different numerical apertures and combined based on image sharpness to create a digital result image with enhanced overall sharpness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the numerical aperture is increased to improve resolution, then the resolving power is improved, but the depth of field decreases

Engineering Contradiction:
Improveresolving powerVSAvoiddepth of field
Core Design Contradiction:
Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent divides the image acquisition process into multiple segments, capturing images at different numerical apertures separately. High NA images capture fine details while low NA images capture broader depth regions, and these segmented images are later combined to achieve both high resolution and extended depth of field simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds the numerical aperture dimension as an additional parameter for image acquisition. Instead of relying solely on z-stacking (depth dimension), the invention introduces NA variation as another dimension, enabling control over both resolution and depth of field through multi-parameter image capture and fusion.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of stationary object

If the numerical aperture is reduced to increase depth of field, then the depth of field is improved, but the resolution decreases

Engineering Contradiction:
Improvedepth of fieldVSAvoidresolving power
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the imaging task by assigning different NA values to different imaging operations. Low NA is used for capturing images with extended depth of field, while high NA is used for capturing images with fine detail resolution, and the segmented results are fused to achieve both goals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using different numerical apertures for different spatial regions or depth layers of the sample. Regions requiring fine detail are imaged with high NA, while regions requiring broader depth coverage use low NA, optimizing the quality characteristics locally across the entire sample volume.

Inventive Principle:
Principle #3Local quality

3Length of stationary object

If z-stacking is used to improve depth of field coverage, then the depth coverage is improved, but the equipment complexity and acquisition time increase

Engineering Contradiction:
Improvedepth coverageVSAvoidequipment requirements
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical z-stacking system with an optical parameter variation system. Instead of physically moving the stage or objective to change focal planes, the invention varies the numerical aperture parameter to achieve different depth of field characteristics, eliminating the need for complex mechanical positioning systems.

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

Solution Approach 2:

The patent achieves depth coverage by changing the numerical aperture parameter rather than changing the physical position of optical components. By adjusting NA, the system modifies the light cone angle and corresponding depth of field, providing a non-mechanical method for exploring different depth regions.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If multiple images at different numerical apertures are captured and combined, then the overall sharpness is improved, but the image processing complexity increases

Engineering Contradiction:
Improveoverall sharpnessVSAvoidimage processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces sharpness evaluation metrics as an intermediary mechanism to objectively assess and compare images captured at different numerical apertures. This intermediary evaluation system guides the selection and fusion process, making the complex multi-image processing systematic and automated rather than arbitrary.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates multiple copies of the same sample at different numerical aperture settings, allowing comparison and fusion of these copies to produce a final image with superior sharpness. The copying approach enables parallel acquisition of complementary information that is later synthesized through processing.

Inventive Principle:
Principle #26Copying

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 method enables high-quality image acquisition with improved sharpness and depth of field, reducing equipment and time requirements compared to traditional z-stacking methods, and is suitable for both single-channel and stereomicroscope systems.

Implementation Method 1

Reflection of light by an object to be examined with a microscope

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

Transmission of light through an object to be examined with a microscope

Methodology Applied
Scientific EffectLight transmission: Refraction

Implementation Method 3

The maximum resolving power of a microscope in the focal plane of the lens is limited by light diffraction, which in turn is determined by the numerical aperture of the imaging system

Methodology Applied
Scientific EffectLight diffraction: Diffraction

Implementation Method 4

For geometric reasons, this decreases with increasing numerical aperture and follows the numerical aperture reciprocally

Methodology Applied
Scientific EffectGeometric optics: Geometry

Data Source

PatentEP3017334B1Image capture method for microscope system and corresponding microscope system
Publication Date: 2020.03.04 LEICA MICROSYSTEMS (SCHWEIZ) AG
  • EP3017334B1 patent drawingFigure 1
  • EP3017334B1 patent drawingFigure 2A~2B
  • EP3017334B1 patent drawingFigure 3

AI summary

The invention relates to a method (200) for providing a digital result image using a microscope system (1) which has means (R, L, 41) for providing microscopic images at different numerical apertures and a digital image capture unit (50). The method comprises capturing at least two microscopic images at different numerical apertures in the form of digital individual images by means of the digital image capture unit (50) and image areas, which correspond to one another, of the digital individual images are compared with one another in terms of the image definition thereof, wherein in each case the image areas of the digital individual images with the highest definition are combined to produce the digital result image.