EMI Artifact Suppression in Digital Radiography via Frequency Band Decomposition

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Solution Overview

Problem

Existing digital radiography technologies face challenges in effectively reducing artifacts caused by electromagnetic interference (EMI)-induced noise, which vary spatially and temporally, and are not adequately addressed by current solutions that assume fixed noise patterns or require complex shielding and filtering methods.

Innovation Solution

A method that identifies the predominant direction of EMI-induced noise artifacts in digital radiographic images, decomposes the image content into frequency bands, applies suppression factors to modify these bands, and recomposes the image to reduce noise, using the image data itself for detection and correction without additional data sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multiplexed readout arrangement is used to optimize usable image-forming area, then device complexity is reduced and manufacturing is easier, but noise artifacts from readout circuitry increase

Engineering Contradiction:

Improvereadout arrangement implementationVSAvoidnoise artifacts from readout circuitry

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The image data is segmented into frequency components using Fourier transform, allowing separate processing of noise frequencies from image frequencies. This enables targeted suppression of circuitry-induced noise while preserving image quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies frequency-domain filtering by modifying specific frequency parameters in the Fourier spectrum. Suppression factors are applied to attenuate noise frequencies while maintaining image frequencies, effectively reducing readout circuitry artifacts.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional noise correction methods are applied, then some noise types are reduced, but EMI-induced noise artifacts remain unaddressed

Engineering Contradiction:

Improvenoise correction effectivenessVSAvoidEMI-induced noise artifacts

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses feedback by comparing the filtered image with the original image, calculating suppression factors based on the difference. This adaptive feedback mechanism continuously optimizes noise suppression while preserving image fidelity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces physical shielding and filtering methods with computational signal processing. By using Fourier transform and frequency-domain filtering, the system eliminates EMI artifacts through mathematical operations rather than physical barriers.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-generated harmful factors

If shielding and filtering methods are used to reduce EMI noise, then noise reduction is achieved, but device complexity and cost increase

Engineering Contradiction:

ImproveEMI noise levelVSAvoidshielding and filtering requirements

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent substitutes complex physical shielding and filtering hardware with computational methods. The Fourier transform-based noise suppression algorithm processes image data to eliminate EMI artifacts, avoiding the need for additional physical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the image data itself to identify and suppress noise, requiring no additional sensors or external data sources. The Fourier analysis and suppression factor calculation are performed self-contained within the image processing pipeline.

Inventive Principle:

Principle #25Self-service

4Manufacturing precision

If frequency domain filtering is applied to suppress noise, then image quality improves, but processing time increases

Engineering Contradiction:

Improveimage qualityVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies partial filtering by selectively processing only the frequency components that contain noise. Rather than filtering the entire frequency spectrum, suppression factors are applied only to noise-dominated frequencies, reducing computational overhead while maintaining image quality.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8055052B2Artifact suppression in diagnostic images

Publication Date: 2011.11.08 CARESTREAM HEALTH INC

AI summary

A method of reducing artifacts in a digital radiographic image identifies either a row or column direction for the artifacts in the image data as a predominant direction and obtains a measurement of the image data frequency content that is subject to artifacts from the image content according to the predominant direction. The measurement of image data frequency content subject to the artifacts is tested according to a predetermined threshold. Artifacts are reduced when the predetermined threshold is exceeded by generating one or more suppression factors according to the testing results, decomposing the image content into at least two frequency bands in each row and column direction, applying the one or more suppression factors to modify at least one of the frequency bands, and recomposing the image content by recombining the at least one modified frequency band with one or more other bands into which the image had been decomposed.