Fourier Domain Sensing via Spatial Modulation
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Solution Overview
Problem
Current imaging technologies face limitations in measuring multiple Fourier components simultaneously, rely on sequential sampling, and require precise optics for high-resolution imaging, which restricts their ability to achieve high-speed, flexible, and efficient image acquisition and synthesis in two and three-dimensional spaces.
Innovation Solution
The method involves spatially modulating a radiation wavefront using dynamic sinusoidal patterns and detecting the response with single-element detectors to estimate sinusoidal Fourier components, enabling high-speed, flexible, and precision-optics-free imaging through real-time electronic control and parallel sampling in Fourier domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lens-based imaging systems use high numerical aperture (NA) to improve spatial resolution, then resolution is improved, but depth of field decreases inversely with the square of NA
Solution Approach 1:
The patent replaces lens-based optical focusing with a computational Fourier domain sampling approach. Instead of using high-NA optics to achieve resolution, the system uses spatial light modulators to project structured illumination patterns and a single-element detector to measure Fourier components computationally, eliminating the inverse quadratic relationship between resolution and depth of field.
Solution Approach 2:
The patent changes the fundamental parameter for achieving resolution from optical NA to spatial frequency sampling in the Fourier domain. By controlling the spatial frequencies of illumination patterns and sampling the object's Fourier transform directly, the system achieves resolution independent of traditional optical constraints on depth of field.
2Measurement precision
If lens-based imaging systems use high NA optics to achieve high resolution, then resolution is improved, but the working distance decreases to only a few millimeters
Solution Approach 1:
The patent substitutes lens-based high-NA imaging with a Fourier domain sampling system using spatial light modulators and a single-element detector. This computational approach to measuring spatial frequencies eliminates the need for close proximity high-NA optics, allowing imaging at larger working distances.
3Measurement precision
If structured illumination techniques are used to surpass the diffraction resolution limit, then resolution is improved, but imaging speed decreases due to sequential image acquisition
Solution Approach 1:
The patent segments the Fourier space measurement into multiple independent spatial frequency components that can be measured simultaneously. By using a spatial light modulator to project multiple structured illumination patterns and a single-element detector to measure corresponding Fourier components in parallel, the system achieves both high resolution and high imaging speed.
Solution Approach 2:
The patent enables continuous measurement of Fourier components through real-time projection of structured illumination patterns and continuous detection by the single-element detector. This eliminates the sequential acquisition bottleneck, maintaining high imaging speed while achieving super-resolution through Fourier domain sampling.
4Measurement precision
If multiple radiation sources and detectors are used to measure Fourier components along distinct paths, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the single spatial light modulator and single-element detector perform multiple functions by dynamically changing the spatial frequencies and orientations of illumination patterns. This programmable approach allows one device to replace multiple fixed sources and detectors, achieving comprehensive Fourier space sampling with minimal hardware.
Solution Approach 2:
The patent uses dynamic control of the spatial light modulator to vary illumination patterns in real-time, enabling a single detector to measure multiple Fourier components sequentially and in parallel. This dynamic reconfiguration replaces static multiple-source/multiple-detector systems with a flexible single-device solution.
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, high-speed imaging without the need for precise optics, enabling super-resolution, flexible sampling, and efficient image synthesis across two and three-dimensional spaces, while reducing the complexity and cost associated with traditional imaging systems.
Implementation Method 1
the object is illuminated with one or more sinusoidal interference patterns that may be generated by an array of radiation sources
Implementation Method 2
the angle of light diffracted or emitted by each Fourier component varies with may be proportional to its spatial frequency
Implementation Method 3
optical heterodyne Fourier processor may be used to sequentially synthesize the image
Data Source
AI summary
Methods, systems, and apparatuses are provided for measuring one or more sinusoidal Fourier components of an object. A structured second radiation is generated by spatially modulating a first radiation. The structured second radiation illuminates the object, The structured second radiation is scaled and oriented relative to the object. The object produces a third radiation in response to the illuminating. A single-element detector detects a portion of the third radiation from multiple locations on the object substantially simultaneously for each spatial modulation of the first radiation and for each orientation of the second radiation. A time-varying signal is produced based on said detected portion of the third radiations. One or more characteristics of the one or more sinusoidal Fourier components of the object are estimated based on the time-varying signal.