EPMA Image Alignment Using Overlapping Partial Reference Images
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Solution Overview
Problem
Electron probe micro-analyzers (EPMA) face challenges in simultaneously measuring multiple elements due to positional deviations in X-ray maps acquired at different times, which can lead to incorrect correlation analysis.
Innovation Solution
An analyzer and image processing method that corrects positional deviations by dividing measurement and reference images into partial images, calculating positional deviation amounts, and adjusting image sizes and overlapping areas to ensure accurate alignment, allowing for simultaneous measurement of multiple elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple elements are measured separately multiple times using one spectrometer, then the number of measurable elements exceeds the number of spectrometers, but positional deviation is generated among the X-ray maps due to specimen drift
Solution Approach 1:
The patent uses electron images (secondary electron images or backscattered electron images) as an intermediary reference to correct positional deviations in X-ray maps. The electron images serve as a stable reference framework that is not affected by the same drift issues as the X-ray maps, allowing accurate alignment and correlation analysis of multiple elements measured at different times
Solution Approach 2:
The patent implements a feedback mechanism where positional deviation amounts are calculated by comparing electron images acquired at different timings, and this calculated deviation information is then used to correct the X-ray maps. This closed-loop feedback ensures that positional accuracy is maintained across multiple measurements
2Productivity
If X-ray maps are acquired at different timings to measure multiple elements, then more elements can be analyzed, but correlation analysis cannot be correctly performed due to positional deviation
Solution Approach 1:
Electron images serve as a mediator that links multiple X-ray map acquisitions taken at different times. By using the electron images as a common reference framework, the patent enables accurate correlation analysis between elements measured at different timings while maintaining high measurement efficiency
Solution Approach 2:
The patent performs preliminary acquisition of electron images at each measurement timing before acquiring the X-ray maps. This preliminary action establishes a reference framework in advance that facilitates accurate positional alignment and correlation analysis of the subsequently acquired X-ray maps
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 enables accurate correction of positional deviations, including enlargement, reduction, and distortion, ensuring precise alignment of X-ray maps acquired at different times, thereby facilitating correct correlation analysis and reducing the need for repeated measurements.
Implementation Method 1
analyzes a specimen by applying an electron beam to the surface of the specimen and spectrally detecting a characteristic X-ray emitted from the specimen
Implementation Method 2
an electron image data based on detected secondary electrons or back-scattered electrons
Implementation Method 3
wavelength dispersive X-ray spectrometers (WDS)
Data Source
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AI summary
In an analyzer (100), an image processing unit (64) performs processing of: dividing a measurement image (E) into a plurality of partial measurement images (EP), and dividing a reference image (R) into a plurality of partial reference images (RP); calculating a positional deviation amount of each of the partial measurement images (RP) relative to a corresponding partial reference image (R) among the partial reference images (RP); determining whether or not the positional deviation amount is a threshold or less; and correcting positional deviation of the measurement image (E) based on the positional deviation amounts of the plurality of partial measurement images (RP) when the image processing unit (64) has determined that the positional deviation amount is not the threshold or less. The processing of dividing for an Mth time includes processing of: determining whether or not a size of each of the partial measurement images in the processing of dividing for an M-lth time is a reference size or less; and making an overlapping amount of adjacent partial measurement images among the partial measurement images to be larger than the overlapping amount in the processing of dividing for the M-lth time when the image processing unit (64) has determined that the size of each of the partial measurement images for the M-lth time is the reference size or less.