Transient Pixel Defect Detection Using Neighbor Comparison

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Solution Overview

Problem

Imaging systems face challenges in accurately detecting and correcting transient pixel defects, which can lead to incorrect information in digital images, especially in medical diagnosis and other critical applications, as these defects are rare and not necessarily indicative of defective pixels.

Innovation Solution

A method that compares the value of a selected pixel with neighboring pixels, excluding known defective pixels, to identify and correct transient defects by determining maximal, minimal, or median values, and replacing the pixel value with an average of good neighboring pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional defect detection methods are used, then known defective pixels can be corrected, but transient pixel defects cannot be detected or corrected

Engineering Contradiction:
Improvedefect detection accuracyVSAvoiddetection method complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the defect detection process into two distinct phases: (1) detection of transient defects through comparison with neighboring pixels, and (2) correction of both transient and permanent defects. This segmentation allows the system to handle different types of defects with appropriate methods for each, improving overall detection accuracy without overwhelming complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary detection and correction of transient defects before correcting known permanent defective pixels. By identifying and addressing transient anomalies first, the system prevents misclassification of transient defects as permanent defects, thereby improving reliability of the overall defect correction process

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a pixel is flagged as defective based on rare deviations, then transient defects are corrected, but false identification of good pixels as defective increases

Engineering Contradiction:
Improveimage accuracyVSAvoidloss of valid pixel data
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies local quality assessment by comparing each pixel's value with its neighboring pixels rather than using global thresholds. This localized comparison allows the system to distinguish between transient defects (which differ from neighbors) and valid pixels with naturally varying values (which are consistent with neighbors), thereby reducing false positives while maintaining detection accuracy

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system uses feedback from neighboring pixel values to dynamically assess whether a pixel deviation represents a transient defect. By continuously comparing pixel values against their local neighborhood context, the system can identify anomalies that truly represent defects while preserving valid pixel data that merely exhibits natural variation, thus minimizing information loss

Inventive Principle:
Principle #23Feedback

3Ease of operation

If all pixel defects are corrected using the same method, then processing is simplified, but transient and permanent defects are not distinguished properly

Engineering Contradiction:
Improveprocessing simplicityVSAvoiddefect classification accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic defect correction process that adapts the correction method based on the type of defect detected. Transient defects are identified through neighbor comparison and corrected separately from permanent defects using the defect map. This dynamic approach maintains processing simplicity by using automated classification while achieving precise differentiation between defect types through context-aware algorithms

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS8660335B2Transient pixel defect detection and correction
Publication Date: 2014.02.25 VAREX IMAGING CORP
  • US8660335B2 patent drawing
  • US8660335B2 patent drawing
  • US8660335B2 patent drawing

AI summary

A method of processing images produced by an imaging system includes detecting transient defects by comparing the value of a selected pixel with values of a plurality of the neighboring pixels, excluding known defective pixels. The value of the selected pixel may be compared with the maximal or minimal value of the neighboring pixels, and if the comparison shows that the value of the selected pixel exceeds the maximal or minimal value by a predetermined value, then the pixel may be identified as producing transient defect. Alternatively, the value of the selected pixel may be compared with the median value of the neighboring pixels, and if the comparison shows that the value of the selected pixel deviates the median value by a predetermined value, then the pixel may be identified as producing transient defect.