Wavefront Shaping for Imaging Through Scatterers
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Solution Overview
Problem
Existing image capturing apparatuses face challenges in capturing clear images through strong scatterers like fog and smoke due to weakened signal light and noise interference, particularly in high nanoparticle concentrations, which deteriorate the signal-to-noise ratio and require complex optical systems or are vulnerable to vibrations.
Innovation Solution
An image capturing apparatus with a spatial light modulator that shapes the wavefront of light to optimize the luminance value in a target area, using a controller to adjust the delay time and optimize the wavefront shaping process to maximize the objective function, thereby improving the signal-to-noise ratio and reducing noise components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complicated optical system with reference light is used to measure hologram, then the reflected light wavefront can be calculated and phase conjugate wave can be generated, but the system becomes vulnerable to vibrations and complex in structure
Solution Approach 1:
The patent extracts and eliminates the reference light component from the optical system. Instead of using a complex holographic system with reference light, the invention directly measures the wavefront of reflected light from the object and uses this information to generate the phase conjugate wave, thereby simplifying the system structure while maintaining measurement precision.
Solution Approach 2:
The patent creates an optical copy of the reflected light wavefront by measuring its phase and amplitude distribution. This copy is then used to generate the phase conjugate wave through computational methods, eliminating the need for complex physical optical systems and reference light interference patterns.
2Illumination intensity
If phase conjugate wave method is used to irradiate light through scatterer, then the reflected light can be enhanced, but the system becomes vulnerable to vibrations and requires complex optical components
Solution Approach 1:
The patent replaces the mechanical/optical system of phase conjugate wave generation with a computational approach. By measuring the wavefront characteristics of reflected light and performing computational phase conjugation, the system enhances reflected light intensity without requiring complex optical components or being vulnerable to vibrations.
Solution Approach 2:
The patent changes the parameters of the incident light wavefront by measuring the phase and amplitude distribution of reflected light and computationally generating the phase conjugate wave. This parameter transformation enhances the reflected light intensity while avoiding the need for complex optical systems.
3Illumination intensity
If optimization process with spatial light modulator is used to shape wavefront, then light can be focused through scatterer, but the objective function setting becomes difficult when no fluorescent light is available
Solution Approach 1:
The patent implements a feedback mechanism where the wavefront of reflected light is continuously measured and used to adjust the spatial light modulator settings. This feedback loop enables the system to optimize light transmission through the scatterer by using the actual reflected light characteristics as the objective function, eliminating the need for fluorescent light or complex objective function formulation.
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 apparatus effectively captures images with a high signal-to-noise ratio even in strong scattering conditions, using a simple structure and minimizing noise interference, by iteratively optimizing the wavefront of light to enhance image clarity and intensity.
Implementation Method 1
a spatial light modulator configured to shape a wavefront of light traveling from a light source to an object
Implementation Method 2
a controller configured to control the spatial light modulator and to make the image capturer capture the image when object light among the light reaches the image capturer via the object
Implementation Method 3
The controller performs an optimization control of the spatial light modulator so as to maximum or minimize a value of an objective function set by using a luminance value in a target area corresponding to the object light in the image data
Data Source
AI summary
An image capturing apparatus includes a spatial light modulator configured to shape a wavefront of light traveling from a light source to an object, an image capturer configured to generate image data by capturing an image of the object, and a controller configured to control the spatial light modulator and to make the image capturer capture the image when object light among the light reaches the image capturer via the object. The controller performs an optimization control of the spatial light modulator so as to maximum or minimize a value of an objective function set by using a luminance value in a target area corresponding to the object light in the image data.