Complex Amplitude Retrieval from Defocused Images
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Solution Overview
Problem
Current methods for generating three-dimensional images from a scene using defocused images are limited by blurring due to the absence of information in certain spatial frequencies, especially in low lighting scenarios, and only allow correction of aberrations on the optical axis, restricting the accuracy of optical reconstruction and resolution.
Innovation Solution
A method that captures a plurality of images at different planes of focus, determines the accumulated wavefront phase using a system of equations, and retrieves the complex amplitude of the electromagnetic field from defocused images, enabling tomographic phase distribution and improved optical resolution without the need for multiple viewpoints, using a conventional camera with a single lens and sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If working in the transform domain with few defocused images, then the method is suitable for low lighting scenarios, but blurring occurs due to absence of information in certain spatial frequencies
Solution Approach 1:
The patent transitions from working in the transform domain to working directly in the measurement domain (spatial domain). This dimensional change allows the method to utilize intensity information from defocused images more effectively, recovering spatial frequency information that would otherwise be lost, thereby reducing blurring while maintaining low lighting suitability.
Solution Approach 2:
The patent changes the working domain parameter from transform domain to measurement domain. This parameter change fundamentally alters how information is processed, enabling the recovery of complete spatial frequency information from defocused images without requiring additional viewpoints or increasing lighting intensity.
2Ease of operation
If using curvature sensor or geometric sensor to retrieve wavefront phase from two defocused images, then the measurement process is simplified, but only aberrations on the optical axis can be corrected
Solution Approach 1:
The patent develops a method that serves multiple functions: it retrieves wavefront phase information (like curvature sensors) while simultaneously enabling aberration correction across the entire field of view (unlike geometric sensors limited to optical axis). This multi-functionality resolves the contradiction between operational simplicity and correction versatility.
Solution Approach 2:
The patent segments the wavefront phase retrieval process into multiple steps working in the measurement domain, allowing different regions of the field of view to be processed independently. This segmentation enables comprehensive aberration correction across the entire field while maintaining the simplicity of using only two defocused images.
3Loss of information
If capturing images at multiple planes of focus, then tomographic phase distribution can be obtained, but the device complexity increases
Solution Approach 1:
The patent uses a single camera system to capture multiple images at different planes of focus, effectively creating copies of the same optical system at different focal distances. This approach obtains complete tomographic phase distribution information without requiring multiple physical cameras or complex multi-viewpoint systems, thereby reducing device complexity while maintaining information completeness.
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
Enables the generation of three-dimensional images and tomographic phase distribution from a single viewpoint, improving optical resolution and correcting aberrations across the entire field of view, while allowing real-time acquisition and reducing blurring issues associated with working in the transform domain.
Implementation Method 1
capturing a plurality of images of the scene by means of a photographic camera, the images being focused in planes of focus arranged at different distances, wherein the camera comprises a lens of focal length F
Implementation Method 2
determining the accumulated wavefront to the conjugate plane in the object space corresponding to the intermediate plane with respect to the planes of focus of the two images of the pair, determining the wavefront W(x,y)
Data Source
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AI summary
A method for determining the complex amplitude of the electromagnetic field associated with a scene, comprising a) capturing a plurality of images of the scene by means of a photographic camera, the images being focused in planes of focus arranged at different distances, wherein the camera comprises a lens of focal length F and a sensor arranged at a certain distance from the lens in its image space, taking at least one image pair from the plurality of images and determining the accumulated wavefront to the conjugate plane in the object space corresponding to the intermediate plane with respect to the planes of focus of the two images of the pair.