Turbulence Compensation Using Dual-Pixel Defocus Disparity
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Solution Overview
Problem
Current methods for measuring and compensating atmospheric turbulence in image processing are inefficient, particularly due to the lack of real-time, spatially local, and accurate estimation of turbulence strength, which affects image quality in long-distance surveillance and astronomical imaging.
Innovation Solution
The method involves using a dual-pixel autofocus sensor to capture and process image data, determining defocus disparity between left and right pixel data to estimate the strength of phase fluctuations caused by atmospheric turbulence, and applying tile-based turbulence compensation using a look-up table to correct for these fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Shack-Hartmann wavefront sensors are used to measure turbulence strength, then turbulence profiling can be achieved, but the system requires multiple frames and cannot provide real-time estimation
Solution Approach 1:
The patent replaces the mechanical Shack-Hartmann wavefront sensor system with a computational approach using standard image sensors. By analyzing image data through algorithms that detect defocus and estimate turbulence strength from image statistics, the system achieves real-time measurement without requiring multiple frames or specialized optical components.
2Measurement precision
If Shack-Hartmann wavefront sensors are used, then turbulence strength can be estimated, but the sensors require a point source (guide star) which is not always available
Solution Approach 1:
The patent makes the turbulence measurement system universal by enabling it to function with any extended light source rather than requiring a specific point source. The image-based algorithm can process data from various imaging scenarios including astronomical imaging, long-distance surveillance, and terrestrial photography, making the system adaptable to multiple applications without guide stars.
3Measurement precision
If Shack-Hartmann wavefront sensors are used, then turbulence measurement is possible, but the sensors have small working area making them unsuitable for wide-field applications
Solution Approach 1:
The patent divides the wide-field image into multiple regions or tiles, applying turbulence analysis to each segment independently. This segmentation approach allows the system to measure turbulence across the entire wide field of view rather than being limited to a small sensor area, maintaining measurement precision while expanding coverage to include wide-field astronomical and surveillance applications.
4Measurement precision
If Shack-Hartmann wavefront sensors are used, then turbulence strength can be measured, but specialised optics are required which significantly raises cost and size
Solution Approach 1:
The patent uses standard commercial image sensors to capture images that serve as copies of the turbulent scene, rather than requiring specialized wavefront sensors. By extracting turbulence information from these image copies through computational analysis, the system achieves accurate measurement while eliminating the need for expensive, complex specialized optical components.
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
This approach enables real-time, spatially local estimation and compensation of atmospheric turbulence, improving image quality by reducing phase fluctuations and enhancing resolution in long-distance imaging applications.
Implementation Method 1
determining a wavefront deviation of the wave deforming medium using a defocus disparity between the first image data and the second image data
Implementation Method 2
atmospheric turbulence is a well-known source of distortion that can degrade the quality of images and videos acquired by cameras viewing scenes from long distances
Implementation Method 3
The blurring and flickering is due to fluctuation in the refractive index of Earth's atmosphere
Implementation Method 4
compensating the image data captured by the sensor for phase fluctuations caused by the wave deforming medium using the determined wavefront deviation
Data Source
AI summary
One or more embodiments of an apparatus, system and method of compensating image data for phase fluctuations caused by a wave deforming medium, and storage or recording mediums for use therewith, are provided herein. At least one embodiment of the method comprises capturing, by a sensor of an imaging system, first image data and second image data for each of a plurality of pixel positions of the sensor, the sensor capturing an object through a wave deforming medium causing a defocus disparity between the first image data and second image data; and determining the defocus disparity between the first image data and the second image data, the defocus disparity corresponding to a defocus wavefront deviation of the wave deforming medium. The method may further comprise compensating the image data captured by the sensor for phase fluctuations caused by the wave deforming medium using the determined defocus disparity.