RSOM Axial Displacement Correction for Motion Artifacts

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Solution Overview

Problem

Raster-scan optoacoustic mesoscopy (RSOM) imaging is affected by motion artifacts due to subject movement, particularly in three-dimensional reconstructions, which degrade image quality and resolution.

Innovation Solution

A system and method for optoacoustic imaging that includes an irradiation unit, a detection unit, and a processing unit to correct axial displacements in detection signals by determining and reducing offsets in the time or spatial courses of detection signals, allowing for improved reconstruction of images by accounting for object movement during data acquisition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data acquisition time is extended to improve image quality through averaging, then image quality improves, but subject motion artifacts increase

Engineering Contradiction:
Improveimage qualityVSAvoidmotion artifacts
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs a preliminary motion correction step before image reconstruction. Detection signals are analyzed to determine axial displacement, and correction values are calculated in advance. These correction values are then applied to the detection signals before they are used for image reconstruction, thereby eliminating motion artifacts prior to the final imaging process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical motion restriction methods (such as suction or adhesive tape) with a signal processing approach. Instead of physically constraining the subject, the system uses computational methods to detect and correct axial displacement in detection signals, substituting mechanical constraints with electronic/digital correction mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If axial displacement correction is applied to detection signals, then image resolution improves up to 5-fold, but data processing complexity increases

Engineering Contradiction:
Improveimage resolutionVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The correction process is segmented into distinct steps: (1) determining axial displacement from detection signals, (2) calculating correction values based on the determined displacement, and (3) applying corrections to the detection signals. This segmentation allows each step to be optimized independently and facilitates implementation in existing imaging systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses the detection signals themselves to determine the axial displacement that caused motion artifacts. The same detection signals that contain the artifacts also provide the information needed to correct them, eliminating the need for separate motion tracking sensors or additional measurement systems.

Inventive Principle:
Principle #25Self-service

3Reliability

If motion correction is implemented in real-time, then image quality improves, but processing time increases

Engineering Contradiction:
Improveimage qualityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Motion correction is performed as a preliminary step before image reconstruction. By correcting the detection signals in advance, the system avoids the need for complex post-processing or iterative reconstruction methods, thereby reducing overall processing time while maintaining image quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces time-consuming mechanical motion restriction methods with rapid signal processing. The electronic/digital correction of axial displacement in detection signals occurs much faster than physical constraint methods, reducing processing time while achieving superior motion artifact elimination.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This approach significantly reduces motion artifacts, enhancing image resolution up to 5-fold by accurately correcting for axial displacements, thereby improving the quality of optoacoustic images in RSOM.

Implementation Method 1

Optoacoustic imaging is based on the photoacoustic effect, according to which ultrasound waves are generated due to absorption of transient electromagnetic radiation by an object, e.g. a biological tissue, and a subsequent thermoelastic expansion of the object.

Methodology Applied
Scientific EffectPhotoacoustic effect: Photoacoustic Effect

Implementation Method 2

The ultrasound waves are detected and converted into electrical signals, based on which an image can be reconstructed.

Methodology Applied
Scientific EffectAcoustic wave detection and conversion:

Data Source

PatentEP3654828B1System for optoacoustic imaging, in particular for raster-scan optoacoustic mesoscopy, and method for optoacoustic imaging data processing
Publication Date: 2024.01.10 HELMHOLTZ ZENT MUENCHEN DEUT FORSCHUNGSZENTRUM FUER GESUNDHEIT & UMWELT (GMBH)
  • EP3654828B1 patent drawingFigure 1a~1g
  • EP3654828B1 patent drawingFigure 2a~2g
  • EP3654828B1 patent drawingFigure 3a~3d

AI summary

The invention relates to system for optoacoustic imaging, in particular for rasterscan optoacoustic mesoscopy (RSOM), and an according method for optoacoustic imaging data processing. The system comprises: an irradiation unit configured to irradiate an object comprising biological tissue with electromagnetic radiation, a detection unit configured to detect acoustic waves generated in the object at a plurality of locations along an axial dimension and along at least one lateral dimension, which is perpendicular to the axial dimension, in response to irradiating the object with electromagnetic radiation and to generate a plurality of according detection signals, and a processing unit configured to determine an axial displacement of the course of one or more first detection signals along the axial dimension relative to the course of one or more second detection signals along the axial dimension, to correct the detection signals by reducing and/or eliminating the axial displacement, and to reconstruct at least one image of the object based on the corrected detection signals. The invention allows for a correction and/or elimination of effects caused by motion of the object in a simple and reliable way.