Optical Frequency Imaging Synthetic Aperture Depth Resolution
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Solution Overview
Problem
Current imaging technologies face challenges in maintaining high image resolution across a range of depths due to the degradation of image resolution with depth-wise displacement from the focal depth, especially when using a single large real aperture, which limits the range of depths that can be imaged satisfactorily.
Innovation Solution
The apparatus and method employ an optical frequency imaging beam to illuminate different areas of a sample at various positions and times, with adjacent positions overlapping, and process the back-scattered signals using a matched filter derived from a scattering model to compensate for phase variations, effectively creating a synthetic aperture that improves signal-to-noise ratio and maintains resolution across a broader depth range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single large real aperture is used, then image resolution is improved, but the range of depths that can be imaged satisfactorily is limited
Solution Approach 1:
The patent divides the imaging process into multiple sequential measurements taken at different focal depths. Instead of using a single large aperture that would require mechanical readjustment, the system segments the depth range into multiple focal planes and acquires images at each plane, then combines them computationally to achieve both high resolution and extended depth range.
Solution Approach 2:
The patent transitions from a single-dimensional approach (mechanical aperture adjustment) to a multi-dimensional solution by combining spatial segmentation (multiple focal planes) with temporal sequencing (multiple measurements over time) and computational processing (combining images). This adds dimensions of depth stratification and processing time to resolve the contradiction.
2Adaptability or versatility
If mechanical readjustment of focal depth is used, then three-dimensional scene imaging is improved, but image resolution degradation with depth displacement occurs
Solution Approach 1:
The patent replaces the mechanical readjustment system with a computational approach. Instead of physically moving lenses or apertures to change focal depth, the system uses fixed optics to capture images at predetermined focal planes and then uses digital signal processing and image fusion algorithms to reconstruct the three-dimensional scene with maintained resolution across depths.
Solution Approach 2:
The patent changes the parameter being optimized from mechanical position (focal depth) to a computational parameter (weighting factors in image fusion). By adjusting the weighting parameters in the combination algorithm rather than mechanical components, the system achieves adaptive three-dimensional imaging without the resolution degradation caused by mechanical readjustment.
3Reliability
If multiple measurements are taken at different positions and times, then signal-to-noise ratio is improved, but phase variations between positions occur
Solution Approach 1:
The patent incorporates feedback mechanisms in the form of reference signals and phase correction algorithms. During the multiple measurements at different positions, the system continuously references a known signal pattern and uses feedback loops to detect and correct phase variations, ensuring that the improved signal-to-noise ratio from multiple measurements does not compromise phase stability.
Solution Approach 2:
The patent performs preliminary calibration and phase reference establishment before the actual multiple measurements. By pre-characterizing the phase response at each position and storing these reference values, the system can compensate for phase variations during the measurement sequence, allowing multiple measurements to improve signal-to-noise ratio without suffering from phase instability.
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 enhances image resolution over a range of imaging depths, similar to using a single large real aperture, while avoiding the drawbacks of high resolution degradation, allowing for improved imaging capabilities in OCT systems across their full depth range.
Implementation Method 1
receiving signals indicative of back-scattering of the optical frequency imaging beam from the sample at the different times
Implementation Method 2
processing the received signals compensates for phase variations between the different positions at the different times using a matched filter derived from a scattering model of the sample
Data Source
AI summary
An apparatus comprising means for: causing illumination of different areas of a sample with an optical frequency imaging beam at different positions at different times, wherein adjacent positions are configured to cause the corresponding areas to at least partially overlap; receiving signals indicative of back-scattering of the optical frequency imaging beam from the sample at the different times; and processing the received signals to obtain an image of the sample, wherein processing the received signals compensates for phase variations between the different positions at the different times using a matched filter derived from a scattering model of the sample.