Metalens Image Correction for 2nd-Order Light Artifacts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Metalenses suffer from focusing inefficiencies, particularly due to 2nd order parasitic light that creates unfocused bright spots and affects image quality, especially when imaging objects at different optical depths.
Innovation Solution
An imaging system and method that utilizes a controllable light source to illuminate the field of view with different illumination intensities and wavelengths, calculating and correcting pixel values based on measured and expected differences to compensate for 2nd order light artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a metalens is used to focus light onto an image sensor, then miniaturization and simplification of optics is achieved, but 2nd order parasitic light creates unfocused bright spots that deteriorate image quality
Solution Approach 1:
The system captures a reference image without the object present to pre-characterize the 2nd order light distribution pattern. This preliminary measurement enables subsequent subtraction of the parasitic light effect from actual images, resolving the contradiction by preparing correction data in advance.
Solution Approach 2:
The patent converts the harmful 2nd order parasitic light into a measurable and correctable artifact. By capturing the parasitic light pattern separately and subtracting it from images containing objects, the system transforms the previously harmful effect into a manageable computational step, thereby improving image quality while maintaining the compact metalens design.
2Measurement precision
If a metalens focuses monochromatic light, then focusing performance is improved, but the system cannot handle objects at different optical depths effectively
Solution Approach 1:
The system performs preliminary capture of reference images at multiple depth planes to pre-map the 2nd order light characteristics across different optical depths. This enables subsequent images at various depths to be corrected using the pre-characterized parasitic light patterns, resolving the contradiction between focusing precision and depth adaptability.
Solution Approach 2:
The patent employs parameter changes by capturing reference images under different illumination conditions (different wavelengths and intensities). This enables the system to characterize and correct 2nd order light effects across multiple parameters, thereby improving both focusing precision and adaptability to different optical depths simultaneously.
3Manufacturing precision
If multiple images are captured at different illumination conditions for correction, then image quality is improved, but the time required for image acquisition increases
Solution Approach 1:
The system captures comprehensive reference images under multiple illumination conditions in advance, before actual imaging. This preliminary characterization of 2nd order light across different wavelengths and intensities enables rapid correction of subsequent images without requiring multiple captures for each imaging scenario, thereby resolving the contradiction between image quality and acquisition time.
Solution Approach 2:
The patent creates a computational model (copy) of the 2nd order light behavior based on preliminary reference captures. This model can then be applied to correct actual images rapidly without requiring repeated measurements under different illumination conditions, thus improving image quality while minimizing time loss.
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 effectively corrects images captured with metalenses, producing high-quality, artifact-free images suitable for extended-reality applications and time-of-flight cameras by compensating for 2nd order light effects.
Implementation Method 1
a controllable light source; controlling the controllable light source to illuminate a field of view of the image sensor using at least one of: a first illumination intensity, a first illumination wavelength
Implementation Method 2
a metalens that is to be employed to focus incoming light onto the image sensor; metalenses employ metasurfaces having nanostructures to focus light
Implementation Method 3
an image sensor; controlling the image sensor to capture a first image; controlling the image sensor to capture a second image
Data Source
AI summary
An imaging system includes a controllable light source; an image sensor; metalens for focusing incoming light onto the image sensor; and processor(s). The processor(s) is configured to control a light source using a first illumination intensity and/or first illumination wavelength, while controlling the image sensor to capture first image; control the light source using a second illumination intensity and/or second illumination wavelength, while controlling the image sensor to capture a second image; calculate measured differences between pixel values of pixels in the first image and pixel values of corresponding pixels in the second image; estimate expected pixel value differences based on difference between the first and second illumination intensities and/or differences between the first and second illumination wavelengths; and correct pixel values of pixels in the first image and/or second image based on deviation in measured differences from expected differences.