Monochromatic Sensor Imaging via Chromatic Aberration
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Solution Overview
Problem
Conventional color digital imaging using the Bayer mosaic leads to color aliasing and requires expensive, bulky lenses to correct chromatic aberrations, which degrades image quality and increases costs.
Innovation Solution
A digital imaging system that captures a sequence of images with a monochromatic image sensor and an optical imaging lens with chromatic aberration, processing sub-frames at different focal positions to determine pixel color composition and distance, eliminating the need for a color filter mosaic and allowing for improved resolution and spectral sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a Bayer mosaic is used for color separation, then color information can be detected, but color aliasing occurs and image resolution deteriorates
Solution Approach 1:
The patent removes the color filter mosaic from the image sensor surface, extracting only the monochromatic sensing capability. Color information is then obtained through computational methods by capturing multiple images at different lens positions and processing them to determine spectral composition, thereby eliminating color aliasing while maintaining resolution.
Solution Approach 2:
The patent replaces the optical color separation mechanism (Bayer mosaic with color filters) with a computational color extraction system. Instead of using physical color filters on the sensor, the system uses image processing algorithms that analyze color signatures from multiple monochromatic images to reconstruct color information without spatial filtering artifacts.
2Loss of information
If an optical low-pass filter is added to decrease color aliasing, then color aliasing is reduced, but image resolution decreases
Solution Approach 1:
The patent replaces the optical low-pass filter with a computational approach. Instead of physically blurring the image to reduce color aliasing, the system captures multiple sharp images at different lens positions and uses image processing to extract color information, thereby avoiding the resolution loss inherent in optical blurring.
Solution Approach 2:
The patent moves the color separation problem from the spatial dimension (2D image plane with color filters) to the optical path dimension (lens position variation). By capturing images at different focal planes and using the chromatic aberration-induced focus shifts, the system separates color information computationally without spatial filtering.
3Measurement precision
If chromatic aberrations are corrected in the lens, then image sharpness is improved, but lens size, weight, and cost increase significantly
Solution Approach 1:
The patent converts the harmful chromatic aberration of simple lenses into a useful feature. Instead of correcting chromatic aberration, the system exploits the wavelength-dependent focus shifts to separate color information. The chromatic aberration causes different wavelengths to focus at different positions, which provides the basis for computational color extraction.
Solution Approach 2:
The patent replaces complex chromatic aberration correction optics with a computational processing system. Instead of using multiple lens elements and complex optical designs to achieve sharp focus for all wavelengths, the system uses image processing algorithms to reconstruct color information from images captured with a simple lens that has uncorrected chromatic aberration.
4Measurement precision
If chromatic aberration correction is applied, then color sharpness is improved, but maximum aperture decreases and minimal focal length increases
Solution Approach 1:
The patent converts the limitation of simple lenses (uncorrected chromatic aberration) into an advantage. The wavelength-dependent focus variation provided by uncorrected chromatic aberration enables computational color separation, allowing the use of simple lenses with large apertures and short focal lengths without sacrificing color sharpness.
Solution Approach 2:
The patent replaces optical chromatic aberration correction systems with computational color extraction. This substitution allows the optical system to maintain simple lens designs with optimal aperture and focal length characteristics, while the computational processing handles color separation that would otherwise require complex optical correction.
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 enhances image resolution and spectral sensitivity while reducing lens size, weight, and cost, and effectively addresses color aliasing without the need for optical low-pass filters or polarizing materials.
Implementation Method 1
an optical imaging lens with chromatic aberration
Implementation Method 2
a monochromatic image sensor and an optical imaging lens with chromatic aberration, processing sub-frames at different focal positions
Data Source
AI summary
Embodiments of imaging devices of the present disclosure obtain color images from a monochromatic image sensor based on a series of several images taken at different focal positions of an optical imaging lens possessing a chromatic aberration.