Optical Coherence Tomography Phase-Varied Scanning for Speckle Reduction
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Solution Overview
Problem
Current optical coherence tomography (OCT) systems for imaging hollow organs face limitations in achieving high lateral resolution and effective noise reduction due to the use of freely resonating B-scan devices, which have a high B-scan frequency and limited A-scans per B-scan, leading to speckle noise and restricted lateral averaging options.
Innovation Solution
The improved OCT system employs a first system unit that obtains OCT-scan data with a higher A-scan frequency relative to the B-scan frequency, utilizing a mutually varying phase relationship, and a second system unit that reorders and consolidates A-scan datasets to generate images with enhanced lateral resolution and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a freely resonating B-scan device is used, then energy consumption is low and the device is robust, but the B-scan frequency is high which limits the number of A-scans per B-scan and reduces lateral resolution
Solution Approach 1:
The system dynamically adjusts the B-scan frequency to be lower than the natural resonant frequency, allowing more A-scans to be performed within each B-scan period. This dynamic frequency control enables optimization between energy consumption and lateral resolution by selecting operating points that balance these competing requirements.
Solution Approach 2:
The patent changes the operating parameter of B-scan frequency from the natural resonant frequency to a lower frequency value. This parameter change allows the system to perform more A-scans per B-scan, thereby improving lateral resolution while maintaining acceptable energy consumption levels through the updated frequency regime.
2Length of moving object
If a freely resonating B-scan device is used, then the device can operate with large scanning amplitude, but the high B-scan frequency limits lateral averaging options and increases speckle noise
Solution Approach 1:
The system uses dynamic frequency control to operate below the resonant frequency, which allows sufficient scanning amplitude to be achieved while performing more A-scans per B-scan. This enables effective lateral averaging across multiple A-scans, thereby reducing speckle noise while maintaining the beneficial large scanning amplitude.
3Productivity
If the B-scan frequency is increased, then the image refresh rate is improved, but the number of A-scans per B-scan decreases which reduces lateral resolution
Solution Approach 1:
The patent optimizes the B-scan frequency parameter to a specific value below the resonant frequency that balances image refresh rate and lateral resolution. By carefully selecting this operating frequency, the system achieves an optimal compromise where sufficient A-scans are performed per B-scan for good lateral resolution while maintaining an acceptable image refresh rate for real-time imaging.
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
The system achieves higher lateral resolution and reduced speckle noise in OCT imaging, maintaining image quality and refresh rate without compromising resolution, suitable for imaging hollow organs like the bladder, uterus, and stomach.
Implementation Method 1
OCT makes use of light instead of soundwaves
Implementation Method 2
OCT is an imaging technique that enables real-time, high resolution, in depth imaging of biological tissues
Implementation Method 3
a detector to detect the merged beam
Data Source
AI summary
An optical coherence tomography (OCT) system (1) is provided that comprises a first system unit (10) and a second system unit (20). The first system unit (10) is configured to obtain OCT-scan data comprising a plurality of B-scan data sets (B1,BnB) from a target (T), each B-scan data set comprising a respective set of A-scan data sets (A1,k,AnA,k). The first system unit (10) is configured to obtain the OCT scan data by repeatedly obtaining an A-scan from the target with a first frequency while performing the B-scan with a second frequency. wherein said repeatedly obtaining with a first frequency and said scanning with a second frequency is performed with a mutually varying phase relationship (Δ1, ΔnB). said first frequency being greater than said second frequency. The second system unit (20) is configured to use information about said mutually varying phase relationship when generating the OCT-image (O) from the OCT-scan data (B1,BnB). Also an optical coherence tomography (OCT) method is provided