Real-time Line Scan Focusing via Multi-sensor Segmentation

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Solution Overview

Problem

Conventional auto-focus methods in microscope imaging systems, such as laser-based interferometers and image content analysis, face challenges with focusing accuracy for tissue samples with large height variations and incur time delays due to the need for multiple image acquisitions at different focus depths.

Innovation Solution

A multiple independent linear sensor apparatus that performs real-time focusing by using a focusing sensor and an imaging sensor in conjunction, where the focusing sensor captures image data ahead of the imaging sensor, allowing for instantaneous or near-instantaneous focusing during line scan imaging by determining optimal focus heights and adjusting the objective lens accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If laser-based interferometer is used for sensing slide position, then global focus information can be obtained, but focusing accuracy for tissue samples with large height variations deteriorates

Engineering Contradiction:
Improvefocus information accuracyVSAvoidfocusing accuracy for large height variations
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent divides the focusing task into multiple independent linear sensors, each responsible for a specific region or depth range. This segmentation allows each sensor to independently measure focus information for its designated area, enabling accurate focusing across tissue samples with large height variations that would be impossible for a single global interferometer measurement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-point interferometric measurement to distributed linear sensor arrays that provide focus information across multiple dimensions (spatial and depth). This dimensional expansion enables the system to capture focus status at multiple locations and depths simultaneously, resolving the limitation of global focus information.

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

2Measurement precision

If multiple image acquisitions at different focus depths are performed, then focusing accuracy can be improved, but time delays between focusing and imaging increase

Engineering Contradiction:
Improvefocusing accuracyVSAvoidtime delay between focusing and imaging
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs focusing sensors to perform preliminary focus detection and measurement before the actual imaging process. By pre-determining the optimal focus position using the focusing sensor array, the system eliminates the need for time-consuming multiple image acquisitions at different depths, achieving both accurate focusing and real-time imaging.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces focusing sensors as intermediary devices that mediate between the objective lens and the imaging sensor. These focusing sensors provide real-time focus information that directly controls the lens positioning, eliminating the need for iterative image acquisition and processing loops that cause time delays.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If conventional auto-focus methods are used, then system complexity can be maintained at acceptable levels, but productivity of digital pathology process deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoiddigital pathology process efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent merges the focusing function and imaging function into a unified real-time operation by using multiple independent linear sensors that simultaneously provide focus information and capture images. This integration eliminates sequential operations and improves productivity without proportionally increasing system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent enables continuous focusing and imaging operations by using the multiple independent linear sensors to continuously monitor and adjust focus position during the scanning process. This continuous action eliminates interruptions and time delays, significantly improving the productivity of the digital pathology process.

Inventive Principle:
Principle #20Continuity of useful action

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 eliminates time delays in image scanning, provides accurate real-time focusing, and ensures high-quality digital image acquisition by optimizing focus heights for each position on the sample, thereby improving the overall efficiency of the digital pathology process.

Implementation Method 1

a focusing sensor and an imaging sensor in conjunction, where the focusing sensor captures image data ahead of the imaging sensor, allowing for instantaneous or near-instantaneous focusing during line scan imaging by determining optimal focus heights

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP3353601B1Real-time focusing in line scan imaging
Publication Date: 2024.12.11 LEICA BIOSYSTEMS IMAGING INC
  • EP3353601B1 patent drawingFigure 1~2
  • EP3353601B1 patent drawingFigure 3A~3C
  • EP3353601B1 patent drawingFigure 4

AI summary

System for acquiring a digital image of a sample on a microscope slide. In an embodiment, the system comprises a stage configured to support a sample, an objective lens having a single optical axis that is orthogonal to the stage, an imaging sensor, and a focusing sensor. The system further comprises at least one beam splitter optically coupled to the objective lens and configured to receive a field of view corresponding to the optical axis of the objective lens, and simultaneously provide at least a first portion of the field of view to the imaging sensor and at least a second portion of the field of view to the focusing sensor. The focusing sensor may simultaneously acquire image(s) at a plurality of different focal distances and/or simultaneously acquire a pair of mirrored images, each comprising pixels acquired at a plurality of different focal distances.