Binary Phase Filter Design for Extended Depth of Field Imaging
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Solution Overview
Problem
Imaging devices face a trade-off between resolution and depth of field, where high-resolution devices have a short depth of field and devices with long depth of field have low resolution, due to the inverse proportionality between depth of field and numerical aperture.
Innovation Solution
Designing a binary phase filter that expands the depth of field by using a binary phase structure and a machine learning-based image reconstruction method, where the filter is optimized through a convolution operation and a penalty function to minimize loss values, and the image reconstruction is enhanced using neural networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the numerical aperture of the lens is increased to improve resolution, then the resolution is improved, but the depth of field becomes shorter
Solution Approach 1:
The patent segments the depth of field into multiple focal planes and captures images at each plane. By dividing the depth range into discrete segments and imaging each segment separately, the system achieves high resolution for each segment while covering a extended total depth range, thus resolving the contradiction between resolution and depth of field.
Solution Approach 2:
The patent transitions from a single-plane 2D imaging approach to a multi-plane 3D imaging approach. By adding the depth dimension as an additional imaging plane, the system maintains high resolution in the lateral dimensions while extending the usable depth range, effectively resolving the trade-off between resolution and depth of field.
2Length of stationary object
If the numerical aperture of the lens is decreased to extend depth of field, then the depth of field is extended, but the resolution becomes lower
Solution Approach 1:
The patent segments the depth of field into multiple focal planes and captures images at each plane. By dividing the depth range into discrete segments and imaging each segment separately, the system achieves high resolution for each segment while covering a extended total depth range, thus resolving the contradiction between resolution and depth of field.
Solution Approach 2:
The patent transitions from a single-plane 2D imaging approach to a multi-plane 3D imaging approach. By adding the depth dimension as an additional imaging plane, the system maintains high resolution in the lateral dimensions while extending the usable depth range, effectively resolving the trade-off between resolution and depth of field.
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 binary phase filter effectively expands the depth of field while maintaining high resolution, overcoming the trade-off between resolution and depth of field, and optimizing image reconstruction quality.
Implementation Method 1
binary phase filter that expands the depth of field by using a binary phase structure
Implementation Method 2
obtaining the images for each depth by a convolution operation of a point spread function (PSF) for each depth within a target DOF section and the test image
Data Source
AI summary
In a method for designing a binary phase filter to expand depth of field and for reconstructing images performed by an electronic device according to an embodiment of the present disclosure, the method includes: obtaining images for each depth for a test image based on a binary phase structure set in the binary phase filter; obtaining reconstructed images for each depth by reconstructing the images for each depth based on a model trained to reconstruct an input image; calculating a loss value of the reconstructed images for each depth by comparing the reconstructed images for each depth with the test image; and updating the binary phase structure until the loss value becomes less than or equal to a predefined value.