Adaptive Image Reconstruction via Gradient-Based Regularization

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Solution Overview

Problem

Current image reconstruction methods in imaging technologies face challenges in dynamically adjusting the regularization strength based on evolving image gradients, particularly with the Huber regularization term, which limits the adaptability and accuracy of the reconstruction process.

Innovation Solution

A system and method that iteratively updates the regularization parameter based on the gradient of the image estimate, allowing for adaptive switching between linear and quadratic regularization, thereby enhancing the stability and noise reduction in the reconstructed image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed regularization parameter is used in the objective function, then the reconstruction process is stable and simple to implement, but the adaptability to different image regions and gradients is poor

Engineering Contradiction:
Improveadaptability to image gradientsVSAvoidcomplexity of regularization parameter adjustment
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the regularization parameter adaptive rather than fixed. The parameter dynamically adjusts based on the gradient magnitude of the image estimate, allowing different regularization strengths in different image regions. This is achieved through the Huber regularization term which automatically transitions between linear and quadratic regularization based on local gradient characteristics, resolving the contradiction between adaptability and complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the regularization parameter based on image gradient information. The Huber regularization term uses a parameter that changes according to the gradient magnitude, switching between different regularization behaviors (linear for large gradients, quadratic for small gradients). This allows the system to adapt to different image features without requiring complex manual parameter adjustment.

Inventive Principle:
Principle #35Parameter changes

2Shape

If linear regularization is used, then edge preservation is improved, but noise reduction capability deteriorates

Engineering Contradiction:
Improveedge preservationVSAvoidnoise in reconstructed image
Core Design Contradiction:
ShapeVSObject-affected harmful factors

Solution Approach 1:

The patent applies the local quality principle by using different regularization types in different image regions based on gradient magnitude. In regions with large gradients (edges), linear regularization is applied to preserve edge sharpness. In regions with small gradients (smooth areas), quadratic regularization is applied to provide stronger noise reduction. This local adaptation resolves the contradiction between edge preservation and noise reduction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements a composite regularization approach by combining linear and quadratic regularization terms through the Huber regularization function. The composite nature of this regularization term allows it to exhibit linear behavior in some regions and quadratic behavior in others, depending on the local gradient characteristics. This composite approach simultaneously achieves edge preservation and noise reduction, resolving the contradiction between these two opposing requirements.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If quadratic regularization is used, then noise reduction is improved, but edge sharpness and spatial resolution deteriorate

Engineering Contradiction:
Improvenoise reductionVSAvoidspatial resolution
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies the local quality principle by selectively applying quadratic regularization only in regions where it is beneficial (smooth areas with small gradients). In edge regions with large gradients, the regularization automatically transitions to linear behavior, preserving spatial resolution and edge sharpness. This localized application strategy resolves the contradiction between noise reduction and spatial resolution.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11037339B2Systems and methods for image reconstruction
Publication Date: 2021.06.15 SHANGHAI UNITED IMAGING HEALTHCARE
  • US11037339B2 patent drawing
  • US11037339B2 patent drawing
  • US11037339B2 patent drawing

AI summary

The present disclosure relates to systems and methods for reconstructing an image in an imaging system. The methods may include obtaining scan data representing an intensity distribution of energy detected at a plurality of detector elements and determining an image estimate. The methods may further include determining an objective function based on the scan data and the image estimate. The objective function may include a regularization parameter. The methods may further include iteratively updating the image estimate until the objective function satisfies a termination criterion, and for each update, updating the regularization parameter based on a gradient of an updated image estimate. The methods may further include outputting a final image based on the updated image estimate when the objective function satisfies the termination criterion.