Imaging Device Diffractive Filter Array Spatial Coding
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Solution Overview
Problem
Conventional imaging devices face challenges in low-light and multi-spectral performance due to limitations in point-spread function (PSF) and the need for complex and costly optical designs, particularly in distinguishing colors and capturing multi-spectral information.
Innovation Solution
An imaging device incorporating a diffractive-filter array (DFA) that diffracts light according to a transform function, allowing for space-variant PSF and enabling multi-spectral or hyper-spectral imaging without absorptive color filters, thereby improving low-light performance and reducing optical complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an absorbing color-filter array (Bayer filter) is placed on the sensor to distinguish colors, then color information can be captured, but low-light performance deteriorates due to light absorption losses
Solution Approach 1:
The patent replaces the mechanical absorptive filtering system (Bayer filter) with a computational approach using a coded aperture mask and image reconstruction algorithms. This substitution eliminates light absorption losses while maintaining color and spectral information capture through mathematical processing of the diffracted light patterns.
Solution Approach 2:
The patent changes the optical parameters by introducing a coded aperture mask with specific transmission patterns that diffract light in controlled ways. By modifying the aperture configuration rather than using absorptive filters, the system achieves spectral discrimination through diffraction-based spatial encoding rather than wavelength-based absorption.
2Measurement precision
If conventional multi-spectral imagers using push-broom operation with prisms or gratings are employed, then multi-spectral information can be captured, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of spectral dispersion and imaging into a single coded aperture mask element. Rather than using separate prisms, gratings, and scanning mechanisms, the coded aperture integrates spectral encoding and spatial imaging in one component, dramatically simplifying the optical design while maintaining multi-spectral capture capability.
Solution Approach 2:
The patent uses a static coded aperture mask that creates multiple diffracted copies of the scene at different spatial locations corresponding to different wavelengths. This copying approach through diffraction eliminates the need for moving parts and complex optical paths required in conventional push-broom multi-spectral imagers.
3Measurement precision
If liquid crystal tunable filters are used to modulate the input spectrum, then multi-spectral imaging can be achieved, but imaging speed decreases and throughput is reduced
Solution Approach 1:
The patent replaces the mechanical liquid crystal tunable filter system with a static coded aperture mask and computational reconstruction approach. This eliminates moving parts and phase transition delays, achieving instantaneous spectral capture across all wavelengths simultaneously through diffraction-based spatial encoding rather than sequential wavelength modulation.
4Measurement precision
If acousto-optic tunable filters are employed for spectral modulation, then multi-spectral imaging can be performed, but power consumption increases and device cost rises
Solution Approach 1:
The patent replaces the power-intensive acousto-optic tunable filter system with a passive coded aperture mask that uses diffraction physics rather than acoustic wave modulation. This eliminates the need for high-power acoustic drivers and complex control electronics, achieving spectral discrimination through geometric optics and computational processing with minimal energy consumption.
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
The solution enhances color and spatial resolution, increases signal-to-noise ratio, and allows for efficient low-light imaging with reduced optical components and manufacturing costs, while maintaining high spectral resolution.
Implementation Method 1
a polychromat positioned at a second distance from the lens, the polychromat being configured to diffract the intermediate image according to a transform function to produce a dispersed sensor image onto the sensor array
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 2A~2B
AI summary
An image capturing device (202) can include a sensor array (210), a lens (230) positioned at a first distance from an intermediate image (235), and apolychromat (220) positioned at a second distance from the lens (230). The poly chro mat (220) can diffract the intermediate image (235) according to a transform function (207) to produce a dispersed sensor image (215) onto the sensor array (210). The dispersed sensor image (215) can represent a spatial code of the intermediate image (235).