Plane Wave Imager Lensless Imaging Resolution
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Solution Overview
Problem
There is a need for high-resolution imaging systems that are lightweight and compact, and existing technologies face challenges in achieving diffraction-limited performance without the need for precise alignment of optical axes, particularly in applications requiring imaging of incoherent light sources.
Innovation Solution
The Plane Wave Imager (PWI) senses incoherent light by splitting it into two streams and measuring the phase difference between them using evanescent couplers, allowing for the calculation of an image through Fourier Transform without the need for lens-based optics, enabling the combination of multiple PWIs to achieve high-resolution imaging equivalent to a large optical aperture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional lens-based imaging systems are used to achieve high-resolution imaging, then imaging quality is improved, but the size and weight of the system increase
Solution Approach 1:
The patent extracts and removes the lens element from the imaging system, replacing it with a lensless imaging approach that uses a spatial light modulator and computational algorithms to achieve high-resolution imaging without the weight and size constraints of traditional optical lenses
Solution Approach 2:
The patent replaces the mechanical optical system (lens-based imaging) with an electro-optical system that uses spatial light modulation and computational processing to achieve imaging, thereby eliminating the need for heavy optical components while maintaining or improving imaging resolution
2Measurement precision
If large optical apertures are used to achieve diffraction-limited performance, then imaging resolution is improved, but the volume and complexity of the system increase
Solution Approach 1:
The patent transitions from relying on physical aperture size in three-dimensional space to achieving resolution enhancement through computational processing in the frequency domain, effectively moving the resolution-enhancing function to a different dimension (computational space) rather than requiring larger physical apertures
3Measurement precision
If multiple small PWIs are combined to achieve large aperture performance, then imaging resolution is improved, but the alignment precision requirements increase
Solution Approach 1:
The patent uses digital copying and computational processing of images from multiple PWIs, where the relative positions and orientations of the individual PWIs are determined through image correlation algorithms rather than requiring precise mechanical alignment during assembly, thereby reducing manufacturing precision requirements
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 allows for high-resolution imaging without the size and weight constraints of traditional lens-based systems, achieving performance equivalent to a large optical aperture while allowing for flexible alignment and reduced complexity in imaging systems.
Implementation Method 1
measuring the phase difference between them using evanescent couplers
Implementation Method 2
the intensity of the interference pattern in a phase-comparator depends co-sinusoidally on the delay between the two light streams
Data Source
AI summary
Plane Wave Imagers (PWI) directly sense the amplitude and phase of electromagnetic waves and do not require a lens to image a scene. PWI's can also be used in the exit pupil of an afocal lens. PWI's are implemented in CMOS using silicon waveguide technology. Since the wavelength of light ranges from less than one to tens of microns, PWI's fabricated on silicon are essentially flat plates, making a PWI a thin and light structure. A CMOS PWI can operate in the visible, near infrared, short wave infrared, and mid wave thermal spectral bands. Benefits of using a PWI include the ability to achieve large optical aperture performance by digitally processing the outputs of multiple small aperture PWI's that are not necessarily precisely optically aligned. Enhanced scene resolution can be obtained by collecting imagery from several adjacent positions and then digitally combining the digital data into one large dataset.