Multi-Angle Illumination Image Correction for Field Curvature
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Solution Overview
Problem
Modern optical systems face challenges in achieving high image quality due to field curvature and astigmatism, which lead to field-dependent defocus errors, and existing correction methods like deconvolution techniques are computationally intensive and inaccurate, especially when rapid image processing is required.
Innovation Solution
The method involves illuminating an object from multiple angles and applying image correction through equalization, using a vector field that accounts for field-point-dependent defocusing, allowing for efficient computational correction of field curvature and astigmatism without deconvolving the point spread function, and combining images to reduce information loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deconvolution techniques are used for image correction, then image quality can be improved, but computational effort increases significantly
Solution Approach 1:
The patent replaces expensive, computationally intensive iterative deconvolution methods with a cheaper, faster alternative using pre-calculated system matrix and linear solving. The system matrix is computed once and stored, enabling rapid image correction without repeated heavy computations.
Solution Approach 2:
The system performs preliminary calculation of the system matrix characterizing the optical aberrations before actual image correction. This pre-computed matrix enables subsequent rapid correction of multiple images without repeating the heavy computational work.
2Ease of manufacture
If cheaper optics are used, then cost is reduced, but field curvature and astigmatism errors increase
Solution Approach 1:
The patent replaces mechanical/optical correction mechanisms (complex high-precision optics) with a computational approach. By using a system matrix to model aberrations and applying digital correction, inexpensive optics can be compensated for their inherent field curvature and astigmatism errors.
3Manufacturing precision
If numerical aperture is reduced to increase depth of field, then field curvature error is reduced, but resolution is lost
Solution Approach 1:
The patent changes the approach from optical parameter adjustment (reducing numerical aperture) to computational parameter correction. By using the system matrix to characterize and correct field curvature errors digitally, the full numerical aperture can be maintained, preserving resolution while correcting field curvature through post-processing.
Data Source
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AI summary
In order to capture images, an object is illuminated about a plurality of illumination angles. A detector detects a plurality of images (41 - 43) of the object for the plurality of illumination angles. An electronic evaluation device uses image correction on the plurality of images (41 - 43), said image correction having equalization (T1, T2, T3), said equalization (T1, T2, T3) being dependent on the illumination angle used for the capturing of the respective images (41 - 43). The corrected images (44 - 46) can be combined.