Electron Microscope Pixel Sensitivity Calibration Using Mode Values
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Solution Overview
Problem
Existing electron microscopes with direct detection cameras face challenges in correcting sensitivity differences between pixels, leading to noise and inaccuracies in image formation.
Innovation Solution
An electron microscope with an image sensor and a correction coefficient calculation unit that determines mode values from frame images captured under a Poisson process condition, calculating correction coefficients to adjust pixel sensitivities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a direct detection camera with multiple sensor pixels is used to capture electron images, then image capture capability is improved, but sensitivity differences between pixels cause noise and reduce measurement precision
Solution Approach 1:
The patent applies preliminary action by performing sensitivity correction before actual image formation. A correction coefficient calculation unit calculates correction coefficients based on mode values obtained under Poisson process conditions, and these coefficients are stored for subsequent application to correct pixel sensitivity differences during normal operation, preventing noise from sensitivity variations.
Solution Approach 2:
The patent changes the parameter of pixel sensitivity by calculating correction coefficients that adjust each pixel's output based on its individual characteristics. The correction coefficients modify the sensitivity parameter of each pixel to achieve uniform response across all pixels, eliminating the sensitivity differences caused by manufacturing variations.
2Reliability
If electrons are directly incident on the image sensor to form images, then direct detection capability is improved, but sensitivity variations between pixels generate noise
Solution Approach 1:
The patent implements feedback by using the output values from sensor pixels under Poisson process conditions to calculate mode values, which then generate correction coefficients. These coefficients are fed back to correct the sensitivity differences in subsequent measurements, creating a closed-loop system that eliminates noise from pixel variations while maintaining direct detection capability.
Solution Approach 2:
The patent changes the sensitivity parameter of each pixel by applying correction coefficients derived from statistical analysis of Poisson-distributed electron incidence. This parameter adjustment equalizes the response across all pixels, eliminating the harmful noise generated by sensitivity variations while preserving the direct detection mechanism.
3Measurement precision
If frame images are captured to enable correction coefficient calculation, then pixel sensitivity correction is improved, but additional processing time is required
Solution Approach 1:
The patent applies preliminary action by capturing frame images and calculating correction coefficients in advance during a calibration phase. This preliminary correction setup stores the necessary correction data for subsequent use, allowing rapid sensitivity correction during actual imaging without repeated time-consuming processing.
Solution Approach 2:
The patent enables self-service by allowing the system to automatically capture frame images and calculate correction coefficients without external intervention. The correction coefficient calculation unit autonomously processes the captured images to generate and store correction data, eliminating the need for manual calibration procedures and reducing overall processing time.
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
The solution effectively corrects sensitivity differences between sensor pixels, improving the accuracy of image formation and reducing noise in electron microscope images.
Implementation Method 1
a camera that includes an image sensor having sensor pixels and captures frame images that are based on output values output from each of the sensor pixels by incidence of the electrons on the image sensor
Data Source
AI summary
An electron microscope includes an electron optical system that irradiates a sample with an electron beam to form an image with electrons transmitted through the sample, a camera that includes an image sensor having sensor pixels and captures frame images that are based on output values output from each of the sensor pixels by incidence of the electrons on the image sensor, and a correction coefficient calculation unit that calculates correction coefficients for correcting sensitivities of the sensor pixels. The correction coefficient calculation unit determines, from the frame images captured under a condition under which the electrons incident on the image sensor follow a Poisson process, a mode value of the output values for each of the sensor pixels, and calculates the correction coefficients based on the mode value determined for each of the sensor pixels.