Extended Depth of Field Imaging via Phase Plate Wavefront Deformation
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Solution Overview
Problem
Conventional imaging systems face challenges in achieving high-resolution, low-light imaging due to the tradeoff between numeric aperture and depth of field, which limits their ability to maintain focus and detect weak fluorescent signals, especially in confocal microscopy and flow cytometry applications.
Innovation Solution
The development of an imaging system with a substantially invariant point spread function (PSF) across an extended depth of field, achieved through techniques such as wave front deformation using phase plates or spherical aberration, allows for the integration of light from different focal positions, enabling de-convolution to enhance image fidelity and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high NA objective is used to improve spatial resolution and light collection, then imaging resolution and sensitivity are improved, but depth of field is reduced by the square of the NA change
Solution Approach 1:
The patent introduces a phase plate in the aperture plane that modifies the wavefront of light in a deterministic way, creating an extended depth of field by adding a third dimension (depth) to the imaging capability while maintaining high lateral resolution through the high NA objective
Solution Approach 2:
The patent changes the optical parameters by introducing a phase plate that deliberately introduces spherical aberration, transforming the point spread function from a narrow focused spot to an extended depth-of-field invariant PSF, thereby extending the usable depth range while maintaining resolution
2Measurement precision
If confocal microscopy is used to achieve optical sectioning and three-dimensional mapping, then imaging detail and focus are improved, but image acquisition rate is significantly reduced
Solution Approach 1:
The patent extracts the depth encoding information from the lateral image plane and maps it to the spectral domain, allowing simultaneous capture of multiple focal planes in a single shot rather than requiring sequential scanning through multiple planes
Solution Approach 2:
The patent replaces the mechanical scanning system of confocal microscopy with an optical encoding system using a phase plate and spectral detector, eliminating the need for physical movement and enabling parallel acquisition of depth information
3Productivity
If conventional fluorescence imaging is used to increase imaging speed, then throughput is improved, but depth of field is reduced leading to compromised images of structures outside the focal plane
Solution Approach 1:
The patent adds depth information as a third dimension encoded in the spectral domain, allowing conventional widefield fluorescence imaging to simultaneously capture information from multiple focal planes without requiring mechanical scanning or sacrificing speed
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 results in high-resolution images with an extended depth of field, improving image quality and sensitivity, enabling the simultaneous focus of all cellular components and enhancing the detection of weak fluorescent signals, thereby overcoming the limitations of traditional imaging systems.
Implementation Method 1
introducing spherical aberration into light from the object
Implementation Method 2
deformation of the wave front of light from an object in a deterministic way
Implementation Method 3
a detector to detect the deformed light and generate image data
Data Source
AI summary
A high speed, high-resolution flow imaging system is modified to achieve extended depth of field imaging. An optical distortion element is introduced into the flow imaging system. Light from an object, such as a cell, is distorted by the distortion element, such that a point spread function (PSF) of the imaging system is invariant across an extended depth of field. The distorted light is spectrally dispersed, and the dispersed light is used to simultaneously generate a plurality of images. The images are detected, and image processing is used to enhance the detected images by compensating for the distortion, to achieve extended depth of field images of the object. The post image processing preferably involves de-convolution, and requires knowledge of the PSF of the imaging system, as modified by the optical distortion element.