Lensless Imaging Fresnel Zone Plate Phase Multiplexing
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Solution Overview
Problem
Existing lensless imaging technologies using Fresnel zone plates struggle to obtain a clear image with a wide angle of view, often resulting in overlapping subject images and reduced imaging range due to the need for multiple physical plates and susceptibility to manufacturing and environmental variations.
Innovation Solution
An image processing apparatus and method that performs two-dimensional complex Fourier transformation on a complex image generated by multiplying a projected image with two Fresnel zone patterns of the same local spatial frequency but different phases, allowing for the removal of noise and specification of the subject's position without physical plates, thus achieving a clear image with a wide angle of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple physical Fresnel zone plates are used to avoid overlapping images, then image clarity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple Fresnel zone plate patterns (first and second patterns with different phases) into a single physical plate structure. The light beam passes through both patterns sequentially within the same plate, eliminating the need for multiple separate plates while maintaining the ability to generate distinct moire fringes for clear image reconstruction.
Solution Approach 2:
The patent uses optical copying through moire fringe generation. The first and second Fresnel zone plate patterns are optically superimposed on the image sensor through interference patterns, creating virtual copies of the patterns that can be processed computationally without requiring separate physical plates for each pattern.
2Adaptability or versatility
If multiple physical Fresnel zone plates are used to achieve wide angle of view, then imaging range is improved, but apparatus size increases
Solution Approach 1:
The patent merges multiple functional patterns into a single compact plate structure, allowing the system to achieve wide-angle imaging capabilities without proportionally increasing the physical size of the apparatus. The combined patterns enable multiple imaging functions within a reduced footprint.
Solution Approach 2:
The single Fresnel zone plate is designed to perform multiple functions by incorporating both the first and second Fresnel zone plate patterns. This multi-functional design allows the same physical component to enable wide-angle imaging and clear image reconstruction simultaneously, rather than requiring separate specialized components.
3Measurement precision
If physical Fresnel zone plates are used, then imaging function is achieved, but manufacturing variations and environmental changes degrade image quality
Solution Approach 1:
The patent introduces asymmetric phase relationships between the first and second Fresnel zone plate patterns. By setting the phase difference to a specific asymmetric value (not equal to 0 or 180 degrees), the system creates distinctive moire fringe patterns that are more robust to manufacturing variations and environmental changes, enabling better discrimination of the true subject position.
Solution Approach 2:
The patent implements a computational feedback mechanism where the image processing unit analyzes the moire fringes generated by the dual patterns and iteratively determines the correct subject position. This feedback loop compensates for manufacturing variations and environmental changes by algorithmically identifying the optimal solution from the interference patterns.
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 enables the acquisition of a clear, non-overlapping image with a wide angle of view without the need for physical Fresnel zone plates, reducing apparatus size and manufacturing costs, and minimizing image quality degradation due to environmental variations.
Implementation Method 1
a Fresnel zone plate is arranged near an imaging element, and the image of the subject can be acquired without a lens by performing Fourier transformation on a moire fringe generated by superimposing a projected image formed on the imaging element by light from the subject
Implementation Method 2
a projected image formed on the imaging element by light from the subject
Implementation Method 3
performing Fourier transformation on a moire fringe generated by superimposing a projected image
Data Source
AI summary
An image processing apparatus according to one aspect of the present invention includes a projected image input unit that inputs a projected image formed by light incident on a Fresnel zone plate from a subject, a complex image generation unit that generates a complex image including an image of a real part and an image of an imaginary part by multiplying the projected image with each of a first Fresnel zone pattern and a second Fresnel zone pattern having the same local spatial frequency in each region and a different phase of the local spatial frequency with respect to the first Fresnel zone pattern, and a Fourier transformation unit that reconstructs an image of a spatial domain by performing two-dimensional complex Fourier transformation on the complex image.