Lensless Orthographic Aerosol Imaging for High-Throughput 3D Reconstruction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for imaging free-flowing aerosol particles in three dimensions are limited by the need for particle confinement or trapping, which restricts the sensing volume and introduces shape-related collection artifacts.
Innovation Solution
A contact-free imaging apparatus using three orthogonal diode lasers of different wavelengths to illuminate particles, forming digital holograms on separate sensors, allowing reconstruction of three-dimensional particle structures without lenses, enabling a large sensing volume and high throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If confocal microscopy or X-ray tomographic microscopy is used to achieve 3D particle imaging, then measurement precision is improved, but device complexity and the need for particle confinement increase
Solution Approach 1:
The patent extracts the particle confinement requirement from the imaging system by using digital holography with lensless imaging. Particles are imaged in free space without being trapped, fixed to a stage, or confined in liquid, thereby eliminating the complex confinement mechanisms while maintaining 3D imaging capability through holographic reconstruction
Solution Approach 2:
The patent creates optical copies (holograms) of particles using digital holography. By recording the interference pattern of light scattered by particles and reconstructing it computationally, the system generates accurate 3D representations without physical contact or confinement, replacing complex mechanical confinement with computational imaging
2Measurement precision
If optical trapping or particle fixation is used to achieve 3D imaging, then measurement precision is improved, but productivity decreases due to limited sensing volume
Solution Approach 1:
The patent extends the sensing volume by utilizing the full three-dimensional space for particle detection. Digital holography captures information from particles at different depths along the optical axis simultaneously, transforming the limited axial detection range into a large volumetric sensing region that accommodates free-flowing particles at high throughput
3Measurement precision
If lens-based microscopy is used for particle imaging, then measurement precision is improved, but the sensing volume is restricted to micrometers or millimeters
Solution Approach 1:
The patent removes the lens component from the imaging system, using lensless digital holography instead. This extraction of the optical element eliminates the depth of focus limitation inherent in lens-based systems, allowing particles throughout a large axial volume to be imaged simultaneously with high resolution through computational reconstruction
Solution Approach 2:
The patent replaces the mechanical/optical focusing mechanism (lenses) with computational processing. Digital holography records the complete wavefront information and uses algorithms to reconstruct sharp images of particles at any depth within the sensing volume, substituting physical focusing with mathematical reconstruction to achieve large sensing volume
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 the creation of three-dimensional images of free-flowing aerosol particles with a large sensing volume and high throughput, facilitating particle classification, identification, and differentiation, and suitable for deployment on unmanned aerial vehicles.
Implementation Method 1
a particle or a collection of particles is illuminated by a laser beam and the interference pattern, i.e., hologram, produced by the particle's forward scattered light
Implementation Method 2
the interference pattern, i.e., hologram, produced by the particle's forward scattered light and the beam is recorded
Implementation Method 3
Methods are available to resolve or reconstruct the 3D form of particles of this size, such as confocal microscopy and X-ray, electron, or optical tomographic microscopy
Data Source
AI summary
Described herein are apparatus and methods for orthographic imaging of particles. Particularly, a method to obtain contact-free images of aerosol particles with digital holography from three orthogonal directions is described and demonstrated. Diode lasers of different wavelengths simultaneously illuminate free flowing particles to form holograms on three sensors. Images of the particles are reconstructed from the holograms and used to infer the three-dimensional structure of single spherical particles or clusters of sphere-like particles. The apparatus employs inexpensive components and requires no lenses to achieve the imaging, which gives it a large sensing volume and simple design.