Wavelength-Scanning Lensless Tomography for Pixel Super-Resolution
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Solution Overview
Problem
Existing lensless on-chip microscopy technologies face limitations in achieving high-resolution three-dimensional imaging of thick samples due to pixel size constraints, mechanical complexity, and inadequate diffraction tomography methods, which result in suboptimal resolution and field of view trade-offs.
Innovation Solution
A wavelength-scanning-based lensless Fourier ptychographic diffraction tomography method that reconstructs three-dimensional refractive index distributions using a supercontinuum laser and acousto-optic tunable filter, employing a series of holograms collected at varying wavelengths to achieve pixel super-resolution and stable imaging without mechanical displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If lensless on-chip holographic microscopy imaging is used to achieve large field of view, then the spatial bandwidth product limitation is solved, but the imaging resolution is limited by pixel size which is far below the optical diffraction limit
Solution Approach 1:
The patent introduces wavelength scanning as an additional dimension to achieve super-resolution. By varying the illumination wavelength and using Fourier ptychographic reconstruction, the system achieves resolution beyond the pixel size limit while maintaining the large field of view capability of lensless imaging
Solution Approach 2:
The patent changes the illumination parameter (wavelength) to achieve super-resolution. By scanning through different wavelengths and using the Fourier ptychographic algorithm, the system reconstructs high-resolution images that overcome the pixel size limitation without requiring mechanical displacement
2Measurement precision
If multi-angle illumination methods are used to achieve three-dimensional imaging, then diffraction tomography capability is improved, but the imaging position changes by tens or hundreds of microns causing effective field of view reduction
Solution Approach 1:
The patent replaces mechanical angle adjustment with wavelength scanning. Instead of physically moving the light source or sample to change illumination angles, the system uses wavelength scanning combined with Fourier ptychographic reconstruction to achieve the same diffraction tomography capability while maintaining a fixed imaging position and large field of view
3Measurement precision
If robotic arms are used to achieve multi-angle illumination, then three-dimensional reconstruction is possible, but the experimental setup becomes complex and expensive
Solution Approach 1:
The patent eliminates mechanical robotic arms by using wavelength scanning with a fixed light source. The Fourier ptychographic algorithm processes the wavelength-scanned holograms to achieve three-dimensional reconstruction, replacing complex mechanical positioning systems with a simpler optical parameter scanning approach
Solution Approach 2:
The patent uses wavelength as a controllable parameter to achieve three-dimensional imaging. By scanning wavelengths and using Fourier ptychographic reconstruction, the system obtains 3D information without requiring mechanical movement, thereby simplifying the experimental setup and reducing costs
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 uniform high-resolution three-dimensional imaging across the entire field of view with improved stability and coherence, overcoming pixel size limitations and mechanical complexity in traditional methods.
Implementation Method 1
a wavelength-scanning illumination source, which includes a supercontinuum laser and an acousto-optic tunable filter
Implementation Method 2
lensless Fourier ptychographic diffraction tomography microscopy imaging method
Implementation Method 3
Recover the refractive index distribution of a three-dimensional object from a hologram sequence is essentially an inverse scattering problem
Implementation Method 4
the imaging resolution is limited by the pixel size of the imaging device
Data Source
AI summary
The invention presents a lensless Fourier ptychographic diffraction tomography microscopy imaging method based on wavelength scanning. The technique uses only a wavelength-tunable light source for illumination on a lensless microscope experimental system to collect a series of coaxial holograms. Then, the three-dimensional scattering potential spectrum is filled using an iterative Fourier ptychographic method to restore the three-dimensional refractive index distribution of the sample directly. The present invention does not require complex modifications to traditional lensless on-chip microscopes. It can endow lensless on-chip microscopes with the ability of pixel super-resolution three-dimensional tomographic imaging.