Coherent Tomogram Phase Correction for Motion Artifacts
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Solution Overview
Problem
Current methods for in vivo three-dimensional imaging face challenges in correcting motion artifacts, particularly in axial and transverse directions, due to the sensitivity of computed optical interferometric techniques and the need for precise phase stability, which is difficult to achieve without stable data or phase references, especially in the presence of aberrations and involuntary tissue movements.
Innovation Solution
A method involving the generation of a broadband optical beam incident on a sample, scanning it in a specified pattern, interfering the scattered light with a reference beam, measuring intensity, and processing data to quantify phase variations, allowing for the correction of generalized motion and aberrations in three-dimensional imaging, using techniques such as speckle tracking and computational refocusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If computed optical interferometric techniques are used for three-dimensional imaging, then imaging resolution and quality are improved, but sensitivity to motion artifacts increases
Solution Approach 1:
The patent measures phase variations continuously during the acquisition of the three-dimensional image volume, before final reconstruction. This preliminary measurement of motion allows the system to capture motion artifacts as they occur and apply corrections during post-processing, rather than attempting to prevent motion entirely or detect it too late.
Solution Approach 2:
The system uses measured phase variations from the interferometric data to generate motion correction parameters that are applied back to the image reconstruction process. This feedback loop allows the system to continuously adjust for motion artifacts based on real-time phase measurements, improving reliability while maintaining high resolution.
2Measurement precision
If phase stability is required for motion correction, then measurement precision is improved, but device complexity increases due to need for external phase references
Solution Approach 1:
The patent extracts phase variation information directly from the interferometric measurement data itself, without requiring external phase references or separate stabilization systems. The system uses the inherent phase information in the OCT signals to self-correct for motion, eliminating the need for additional external reference devices.
Solution Approach 2:
The interferometric measurement system serves multiple functions simultaneously: it captures the primary imaging data and also extracts phase variation information for motion correction. This multi-functionality allows the same optical path and detectors to provide both structural imaging and motion tracking without requiring separate dedicated reference systems.
3Productivity
If scanning speed is increased to avoid motion artifacts, then productivity is improved, but phase measurement precision deteriorates
Solution Approach 1:
The patent replaces mechanical stabilization methods with computational phase correction. Instead of mechanically stabilizing the sample or scanner to maintain phase stability, the system uses digital signal processing to measure and correct phase variations after acquisition, allowing faster scanning speeds without sacrificing phase measurement precision.
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
Enables accurate measurement and correction of phase variations in three-dimensional imaging, improving the stability and quality of in vivo imaging by accounting for motion in all three dimensions without the need for external phase references, thus enhancing the precision and reliability of the imaging process.
Implementation Method 1
interfering light scattered by the sample with a reference beam derived from the broadband optical beam
Data Source
AI summary
Methods and apparatus for assessing and correcting phase variations and motion artifacts in a coherent tomogram of a sample. Coherent techniques are used scan a broadband optical beam across a sample in a specified scan pattern and to acquire a cube of complex data constituting a full tomogram. Generalized motion of the sample is then quantified based at least on a phase variation measured during the course of scanning the broadband optical beam in the specified scan pattern. Generalized motion includes both actual motion and apparent motion due to organized variation of some physical parameter such as temperature. Intensity structure of speckle imaged during the course of coherently acquiring the full tomograpm may be used to correct for motion of the sample in a plane transverse to a depth axis along the incident beam.