Electron Microscope Image Distortion Measurement via Auto-Correlation

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Solution Overview

Problem

Current electron microscope images suffer from distortion due to optical defects and improper scanning techniques, leading to inaccurate measurements of specimen length and shape, necessitating a more precise distortion measurement method.

Innovation Solution

A distortion measurement method involving a distortion measurement specimen with structures arranged in a lattice, where an auto-correlation function is calculated from the electron microscope image, and distortion is measured based on a pattern formed by connecting peak positions, specifically an ellipse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional electron microscope imaging is performed, then images can be obtained, but distortion occurs due to optical defects and scanning issues, leading to inaccurate measurements

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidimage distortion
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary measurement process using auto-correlation function analysis. Instead of directly measuring distorted features in the image, the method uses the auto-correlation function as an intermediary mathematical tool to extract distortion information from the image data, thereby enabling accurate distortion measurement despite optical defects and scanning issues

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct physical measurement methods with mathematical image processing. Instead of using mechanical measurement tools or direct geometric analysis of distorted features, the invention substitutes a mathematical approach using auto-correlation functions to calculate distortion, achieving higher precision without physical contact or additional mechanical systems

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

2Measurement precision

If direct measurement of specimen features is performed on distorted images, then measurement process is simple, but measurement accuracy deteriorates due to image distortion

Engineering Contradiction:
Improvedistortion measurement accuracyVSAvoidmeasurement method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes complex direct measurement procedures with a mathematical image processing approach. The auto-correlation function method replaces manual or mechanical measurement techniques, using computational mathematics to extract distortion parameters from image data, thereby achieving high measurement precision through software-based analysis rather than complex physical measurement systems

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

Solution Approach 2:

The patent transforms the measurement problem from spatial domain to frequency domain by using auto-correlation functions. This parameter transformation allows distortion information to be extracted more accurately by analyzing the statistical relationships between image pixels, converting a geometric measurement problem into a mathematical parameter analysis problem

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3410461B1Distortion measurement method for electron microscope image, electron microscope, distortion measurement specimen, and method of manufacturing distortion measurement specimen
Publication Date: 2021.11.10 JEOL LTD
  • EP3410461B1 patent drawingFigure 1~2
  • EP3410461B1 patent drawingFigure 3
  • EP3410461B1 patent drawingFigure 4~5

AI summary

A distortion measurement method for an electron microscope image includes: loading a distortion measurement specimen (1) having structures arranged in a lattice to a specimen plane of an electron microscope (100) or a plane (14) conjugate to the specimen plane in order to obtain an electron microscope image of the distortion measurement specimen (1); and measuring a distortion from the obtained electron microscope image of the distortion measurement specimen (1).