Spinning Point Spread Function for 3D Particle Localization
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Solution Overview
Problem
Current 3D imaging and sensing technologies face challenges in achieving high resolution and efficient data acquisition, particularly in photo-activation localization microscopy, due to limitations in optical system design and post-processing algorithms, which result in sub-optimal 3D position estimation and extended depth of field issues.
Innovation Solution
The use of spinning point spread functions (PSFs) with enhanced 3D patterns that modify the optical encoding to provide axial ranging and three-dimensional imaging, combined with Phase Retrieval (PR) enabled Maximum Likelihood Estimation (MLE) for precise particle position estimation, allowing for improved resolution and reduced data acquisition time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If axial invariant PSF is used for extended depth of field, then depth range is improved, but manufacturing precision deteriorates due to loss of restoration quality in MTF
Solution Approach 1:
The patent employs asymmetric PSF designs where the point spread function exhibits different characteristics in axial versus transverse directions. This asymmetry allows the optical system to encode depth information in the axial dimension while preserving high-resolution imaging capability in the transverse plane, thereby resolving the contradiction between extended depth range and restoration quality
Solution Approach 2:
The patent transitions from 2D image processing to 3D volumetric imaging by utilizing the axial dimension for depth encoding. Through techniques such as optical sectioning and confocal imaging, the system extracts three-dimensional information from the axial variation of the PSF, enabling extended depth range without compromising transverse resolution
2Manufacturing precision
If rotationally symmetric optical encoding MTF is used, then restoration quality is improved, but measurement precision deteriorates for axial ranging
Solution Approach 1:
The patent deliberately introduces asymmetric PSF characteristics in the axial direction to encode depth information. By making the PSF asymmetric with respect to axial position, the system enables precise axial ranging through analysis of the asymmetric pattern, while maintaining rotationally symmetric MTF for high-quality restoration in the transverse plane
3Ease of manufacture
If classical lens design is used, then ease of manufacture is improved, but productivity deteriorates due to extended data acquisition time
Solution Approach 1:
The patent performs preliminary optical encoding during the image acquisition phase by designing the PSF to inherently contain depth information through its axial variation. This preliminary encoding of 3D information into the optical pattern eliminates the need for subsequent complex post-processing steps, thereby reducing data acquisition time while maintaining ease of manufacture
Solution Approach 2:
The patent replaces mechanical scanning or physical sectioning methods with optical encoding techniques. By using engineered PSFs that naturally encode depth information in the optical domain, the system achieves rapid 3D imaging without mechanical movement, significantly improving data acquisition speed while keeping the optical system relatively simple
4Measurement precision
If photo-activation localization microscopy is used, then measurement precision is improved for particle localization, but loss of time increases due to sequential imaging requirements
Solution Approach 1:
The patent employs periodic photoactivation and photoswitching of fluorophores to achieve super-resolution imaging. By cyclically activating and deactivating fluorescent molecules in different spatial locations, the system captures multiple frames that collectively reveal the complete 3D structure with high precision while reducing the total acquisition time through parallel information gathering
Solution Approach 2:
The patent performs preliminary 3D encoding of particle positions during the photoactivation process itself. By designing the PSF to contain axial position information through its three-dimensional pattern, the system extracts complete 3D localization data from each captured frame without requiring sequential scanning, thereby maintaining high precision while reducing acquisition time
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 enables high-resolution 3D wide-field super-resolved imaging with precise localization of particles, achieving the fundamental limits of precision and improving the resolvable volume by several orders of magnitude compared to classical fluorescence microscopy.
Implementation Method 1
The optical encoding modifies the Point Spread Function of the optical device to consist of a prominent peak or pattern which spins about an axis as it is propagated axially
Implementation Method 2
Photo-activation localization microscopy provides far-field super-resolution imaging techniques based on the periodic photoactivation or photoswitching of the fluorescence emission of sparse arrays of molecules
Data Source
AI summary
Embodiments include methods, systems, and/or devices that may be used to image, obtain three-dimensional information from a scence, and/or locate multiple small particles and/or objects in three dimensions. A point spread function (PSF) with a predefined three dimensional shape may be implemented to obtain high Fisher information in 3D. The PSF may be generated via a phase mask, an amplitude mask, a hologram, or a diffractive optical element. The small particles may be imaged using the 3D PSF. The images may be used to find the precise location of the object using an estimation algorithm such as maximum likelihood estimation (MLE), expectation maximization, or Bayesian methods, for example. Calibration measurements can be used to improve the theoretical model of the optical system. Fiduciary particles/targets can also be used to compensate for drift and other type of movement of the sample relative to the detector.