Symmetric Spectral Relay System for Aberration Correction
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Solution Overview
Problem
Current coded aperture snapshot spectral imager systems suffer from spatial aberrations and inadequate light throughput due to the use of asymmetric relay systems and Prism-Grating-Prism systems, which result in undesirable optical effects like anamorphic distortion and chromatic aberrations, making image reconstruction difficult and less linear.
Innovation Solution
A spectrally shearing optical relay system is proposed, comprising two halves with rotationally symmetric optical elements and compound prisms disposed symmetrically about an aperture stop, which corrects for 'smile' and 'keystone' distortions, providing improved image sharpness and light throughput by using collimated bundles and glasses with anomalous partial dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If asymmetric relay systems or Prism-Grating-Prism systems are used, then spectral dispersion is achieved, but spatial aberrations (anamorphic distortion, chromatic aberrations) increase and light throughput decreases
Solution Approach 1:
The patent applies asymmetry in reverse by designing a symmetric relay system where the first and second relay lenses have equal focal lengths and are positioned symmetrically about the aperture stop. This symmetry cancels out spatial aberrations while the compound prisms provide the necessary spectral dispersion without introducing anamorphic distortion or lateral chromatic aberrations.
Solution Approach 2:
The patent combines multiple functions into the compound prisms: spectral dispersion, image shearing, and aberration correction. The compound prism assembly integrates several prism elements that work together to disperse light spectrally while the symmetric relay system corrects spatial aberrations, eliminating the need for separate correction elements.
2Measurement precision
If conventional relay lenses and dispersing prisms are used, then spectral imaging is achieved, but image sharpness decreases due to anamorphic distortion and lateral chromatic aberrations
Solution Approach 1:
The patent uses symmetric configuration of relay lenses with equal focal lengths positioned equidistantly from the aperture stop. This symmetry ensures that anamorphic distortion and lateral chromatic aberrations introduced by one side are canceled by the other, preserving image sharpness across the spectral range.
Solution Approach 2:
The symmetric relay system creates a mirrored copy of the optical path on either side of the aperture stop. The first relay lens and second relay lens are identical in focal length and positioning, creating symmetric image paths that cancel aberrations and maintain sharpness.
3Measurement precision
If Prism-Grating-Prism systems are used, then spectral dispersion is achieved, but light throughput is insufficient and system cost increases
Solution Approach 1:
The patent extracts the grating element from the traditional Prism-Grating-Prism system and replaces it with compound dispersing prisms. This eliminates the need for the grating while achieving equivalent or superior spectral dispersion through the compound prism assembly, thereby improving light throughput and reducing system complexity.
Solution Approach 2:
The patent uses compound prisms made from multiple glass types with different dispersive properties. By combining prisms of different materials, the system achieves effective spectral dispersion while maintaining high light throughput, avoiding the losses associated with grating-based systems.
4Measurement precision
If reflective systems are used, then spectral imaging is achieved, but spatial aberrations are introduced
Solution Approach 1:
The patent replaces reflective optical elements with transmissive relay lenses and compound prisms. This substitution eliminates spatial aberrations introduced by mirrors while maintaining spectral imaging capability through the transmissive optical path and dispersive prisms.
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 system achieves high sharpness and brightness with reduced manufacturing costs, offering diffraction-limited relaying over specific spectral ranges and minimizing spherical aberrations and coma, thereby enhancing the quality of hyperspectral imaging.
Implementation Method 1
a spectrally shearing optical relay system, said relay system being comprised of two halves disposed symmetrically about an aperture stop S, wherein each half comprises a plurality of rotationally symmetric optical elements forming an objective and a compound prism comprised of a plurality of dispersing prisms
Implementation Method 2
each half comprises a plurality of rotationally symmetric optical elements forming an objective and a compound prism comprised of a plurality of dispersing prisms. The dispersing prisms are designed to simultaneously provide the required spectral shearing and allow the correction of optical aberrations created by the prisms to be corrected by rotationally symmetric optical components
Data Source
AI summary
A spectrally shearing optical relay system, said relay system being comprised of two halves disposed symmetrically about an aperture stop S, wherein each half comprises a plurality of rotationally symmetric optical elements forming an objective and a com-pound prism comprised of a plurality of dispersing prisms. The compound prisms are located between the objectives and the aperture stop. An imaging device with such an optical relay system is also proposed.