Focus Control Unit Using Preliminary Macro Imaging for Segmented Scanning

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Solution Overview

Problem

The existing image capturing apparatuses face an increase in processing time due to the need for pre-focus adjustments when imaging segmented regions, especially when the imaging range is divided into a large number of regions, which can lead to reduced focus accuracy and longer imaging times.

Innovation Solution

An image capturing apparatus that includes a stage, a light source, a light guiding optical system with a light dividing unit, a first imaging unit, a second imaging unit, and a focus control unit that analyzes images to control the focus position, storing control results from previous segmented regions to determine the initial focus position for subsequent regions, thereby simplifying the pre-focus process and reducing processing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pre-focus adjustment is performed for each segmented region, then focus accuracy is maintained, but processing time increases significantly

Engineering Contradiction:
Improvefocus accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing a macro image capture of the entire sample region before dividing it into segmented regions. The focus map is created in advance from this macro image, showing focus positions for all segmented regions. This preliminary focus map creation eliminates the need for time-consuming pre-focus adjustments during subsequent high-magnification imaging of each segmented region, as the objective lens can directly move to predetermined focus positions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a focus map in advance that stores focus positions for multiple segmented regions. This focus map is generated from a macro image captured before the detailed imaging process. By having this preliminary focus information available, the system avoids performing repetitive pre-focus adjustments during the actual segmented region imaging, thereby reducing processing time while maintaining focus accuracy.

Inventive Principle:
Principle #10Preliminary action

2Area of stationary object

If the number of segmented regions is increased to cover a larger imaging range, then imaging coverage is improved, but the number of pre-focus operations increases leading to longer processing time

Engineering Contradiction:
Improveimaging coverageVSAvoidprocessing time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The patent creates a comprehensive focus map in advance that covers all segmented regions within the entire imaging range. This focus map is generated from a macro image that captures the full sample area, allowing the system to pre-determine focus positions for all segmented regions regardless of how many regions are created. This eliminates the need to perform pre-focus operations for each region during imaging.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent divides the imaging process into two segments: a preliminary macro imaging stage that captures the entire sample area to create a focus map, and a subsequent high-magnification imaging stage that processes segmented regions using the pre-created focus map. This segmentation allows the system to handle large imaging ranges by creating once a comprehensive focus guide that serves all segmented regions.

Inventive Principle:
Principle #1Segmentation

3Productivity

If focus acquisition positions are decreased to reduce processing time, then imaging speed is improved, but focus accuracy deteriorates

Engineering Contradiction:
Improveimaging speedVSAvoidfocus accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary macro imaging of the entire sample area to create a comprehensive focus map that contains focus position information for all segmented regions. This preliminary action provides accurate focus position data without requiring multiple focus acquisition operations during high-magnification imaging, thus maintaining focus accuracy while improving imaging speed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a focus map that serves as a copy or representation of the focus information for the entire sample area. This focus map is generated from macro image data and contains predetermined focus positions for all segmented regions. By using this focus map copy, the system avoids performing repeated focus acquisition measurements during actual imaging, thereby maintaining accuracy while improving speed.

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 approach allows for a significant reduction in processing time necessary for imaging by accurately determining the initial focus position using control results from previous regions, maintaining focus accuracy even with a large number of segmented regions.

Implementation Method 1

a light guiding optical system including a light dividing unit which divides an optical image of the sample into a first optical path for capturing an image and a second optical path for focus control

Methodology Applied
Scientific EffectLight guiding: Optical Fibre

Implementation Method 2

a first imaging unit which captures a first image by a first optical image divided into the first optical path

Methodology Applied
Scientific EffectImage capture: Photography

Implementation Method 3

a second imaging unit which captures a second image by a second optical image divided into the second optical path

Methodology Applied
Scientific EffectImage capture: Photography

Implementation Method 4

a focus control unit which analyzes the second image so as to control a focus position of an image pickup by the first imaging unit based on the analysis result

Methodology Applied
Scientific EffectFocus control: Focusing

Data Source

PatentEP2916160B1Image acquisition device and method for focusing image acquisition device
Publication Date: 2020.05.27 HAMAMATSU PHOTONICS KK
  • EP2916160B1 patent drawingFigure 1
  • EP2916160B1 patent drawingFigure 2
  • EP2916160B1 patent drawingFigure 3(a)~3(b)

AI summary

An image capturing apparatus is configured to store the control result of a focus position during scanning of segmented regions 40 and determine an initial focus position in scanning of the (n+1)th segmented region 40, based on the control result stored during scanning of the nth (n is an integer of 1 or more) or earlier segmented region. The foregoing technique allows this image capturing apparatus to roughly determine the initial focus position in the next-scanned segmented region 40 by making use of the control result of the segmented region 40 the scanning of which has been already completed. This can suppress increase in processing time necessary for imaging, by simplification of pre-focus.