Charged Particle Camera Defect Masking for Accurate Event Localization

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Solution Overview

Problem

Conventional charged particle microscopy systems suffer from defects in camera pixels that cause spurious overflow and subpixel localization biases, affecting image quality and reconstruction processes, which are not effectively addressed by existing interpolation methods applied post-image transformation.

Innovation Solution

Implementing a CPM support module that identifies defective pixel regions and working pixel regions, generates adjusted charged particle event indicators to mitigate spurious overflow and subpixel localization, and outputs defect-masked data, allowing for improved reconstruction by processing raw charged particle data within the camera hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional interpolation methods are applied post-image transformation, then defective pixel regions can be partially masked, but spurious overflow and subpixel localization biases persist, degrading image quality and reconstruction accuracy

Engineering Contradiction:
Improvedefect masking effectivenessVSAvoidsubpixel localization accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies defect masking and spurious event removal operations on raw charged particle data before image transformation and reconstruction. By performing these corrections preliminarily on the raw data stream, the system eliminates spurious overflow events and subpixel localization biases at the source, preventing them from propagating through subsequent processing stages and degrading final image quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and removes spurious charged particle events that originate from defective pixel regions. By identifying events that are artifacts of pixel defects rather than genuine sample signals, and selectively removing only these spurious events while preserving valid data, the system maintains measurement precision while improving overall reliability

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If defective pixel regions are masked using neighboring pixel interpolation, then some defect effects are reduced, but processing time increases and reconstruction accuracy deteriorates due to post-transformation correction limitations

Engineering Contradiction:
Improvedefect correction capabilityVSAvoiddata processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs defect correction operations on raw charged particle data before the computationally intensive image transformation and reconstruction steps. By addressing defective pixel effects preliminarily on the raw data stream through efficient event-based filtering and masking, the system reduces the computational burden on subsequent processing stages and minimizes overall processing time while maintaining high reconstruction accuracy

Inventive Principle:
Principle #10Preliminary action

3Productivity

If spurious overflow events from defective pixels are not corrected, then data processing remains simple and fast, but image quality and reconstruction accuracy are significantly degraded

Engineering Contradiction:
Improvedata processing speedVSAvoidcharged particle event detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements self-service defect masking where the system automatically identifies defective pixel regions and configures appropriate masking parameters without requiring manual intervention. The charged particle camera system performs self-diagnosis and self-correction by monitoring pixel performance and dynamically adjusting defect masking strategies, maintaining high processing speed while ensuring accurate spurious event removal

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent applies localized defect masking strategies tailored to specific defective pixel regions. By analyzing the unique characteristics of each defective pixel or pixel cluster and applying customized masking parameters for each region, the system optimizes the balance between processing efficiency and measurement precision, removing only the necessary spurious events while preserving valid data from affected areas

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4198576B1Defective pixel management in charged particle microscopy
Publication Date: 2025.10.29 FEI CO
  • EP4198576B1 patent drawingFigure 1~3
  • EP4198576B1 patent drawingFigure 4A~5
  • EP4198576B1 patent drawingFigure 6

AI summary

Disclosed herein are methods, apparatuses, systems, and computer-readable media related to defective pixel management in charged particle microscopy. For example, in some embodiments, a charged particle microscope support apparatus may: identify a working pixel region of a charged particle camera, wherein the working pixel region is proximate to a defective pixel region in which the charged particle camera cannot detect charged particle events; generate a set of charged particle event indicators that represent a charged particle event in the working pixel region; adjust the set of charged particle event indicators so that a charged particle event intensity over the working pixel region is not significantly greater than a charged particle event intensity over the defective pixel region; and output charged particle event data, wherein the charged particle event data includes data representative of the adjusted set of charged particle event indicators.