Optical Path Modulation for High-Resolution Color Imaging
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Solution Overview
Problem
Conventional color image sensors using Bayer filters face reduced resolution for each color due to spatial separation of colors, resulting in lower information resolution for red and blue colors and half the resolution for green colors.
Innovation Solution
An image acquisition apparatus employing an optical path modulation optical element, such as an electrowetting prism or active liquid crystal element, to shift the optical path of an image on a color filter in a time division manner, allowing for image information acquisition from multiple positions and subsequent combination to achieve high-resolution color images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a Bayer color filter is used to acquire color information, then color information can be obtained for each pixel, but resolution of information for each color is reduced to one fourth for R or B color or by a half for G color
Solution Approach 1:
The patent employs a movable color filter array that can dynamically shift its position in the optical path. By moving the color filter array to different positions, the system captures image information from multiple spatial locations, thereby recovering color resolution that would otherwise be lost due to the Bayer pattern's subsampling. This dynamic repositioning allows each pixel to effectively sample multiple color channels across different positions.
Solution Approach 2:
The invention introduces a temporal dimension to the color imaging process by capturing multiple frames with the color filter array at different positions. Instead of relying solely on spatial separation as in conventional Bayer filters, the system uses time-division multiplexing where the same pixel array captures color information from different spatial locations at different times, effectively adding a temporal dimension to overcome the spatial resolution limitation.
2Loss of information
If spatial separation of colors is used to acquire color information, then color information can be obtained, but resolution of information for each color is reduced
Solution Approach 1:
The patent merges multiple low-resolution color images captured at different positions into a single high-resolution color image. By combining the image information from multiple positions where the color filter array was located at different coordinates, the system reconstructs a full-resolution color image that preserves both color accuracy and spatial detail, effectively merging the subsampled data from various positions.
Solution Approach 2:
The movable color filter array acts as an intermediary that enables indirect sampling of color information. Instead of having each pixel directly sense all color channels simultaneously (which is physically impossible), the system uses the movable color filter array to sequentially present different color filters to different pixel groups, allowing indirect acquisition of complete color information at full resolution through computational reconstruction.
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 color and total resolution of acquired images by shifting the image position in pixel units, enabling the combination of image information from multiple positions to produce high-resolution color images without mechanical movement, thus overcoming the limitations of Bayer filter-based systems.
Implementation Method 1
an optical path modulation optical element configured to shift an incident position of an image on the color filter by electrically modulating an optical path
Implementation Method 2
The optical path modulation optical element may be an electrowetting prism of which an inclination angle of an interface between a first fluid and a second fluid is controlled by an applied voltage
Implementation Method 3
The active liquid crystal element may include at least one of a hologram-type liquid crystal element and a beam-steering liquid crystal element
Implementation Method 4
a photoelectric conversion cell array configured to acquire image information for each color by detecting, in pixel units, light which has passed through the color filter
Data Source
AI summary
An image acquisition apparatus includes a color filter on which a plurality of types of color filter elements are arranged, an optical path modulation optical element configured to shift an incident position of an image on the color filter by electrically modulating an optical path of the image, and a photoelectric conversion cell array configured to acquire image information for each color by detecting, in pixel units, light which has passed through the color filter. A color image is obtained by acquiring, in a time division manner, the image information for each color of the image of which a position is changed by the optical path modulation optical element by using a detection signal of the photoelectric conversion cell array, and combining the acquired image information for each color.