Color Filter Array with Adjacent Green Pixels for Moire Suppression
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Solution Overview
Problem
Existing color imaging elements with single-plate color imaging elements face challenges in suppressing false color moire, particularly in high-frequency sections, due to limitations in Bayer array configurations and complex image processing requirements.
Innovation Solution
A color imaging element with a color filter array where first filters (e.g., green) are arranged to be adjacent to each other in horizontal, vertical, and oblique directions, allowing for determination of luminance correlation directions at minimum pixel intervals, enabling accurate interpolation of other colors and reducing false color generation without the need for optical low-pass filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an optical low-pass filter is arranged on the front side of the color imaging element to prevent high frequency wave reduction, then color moire caused by folding of high frequency signals is reduced, but resolution is reduced accordingly
Solution Approach 1:
The patent removes the optical low-pass filter from the optical path, extracting the harmful filtering function. Instead of preventing high frequency waves optically, the invention processes the data digitally through demosaicing algorithms that analyze correlations in multiple directions (horizontal, vertical, oblique) to suppress color moire while preserving resolution.
Solution Approach 2:
The patent replaces the mechanical/optical low-pass filter with a digital signal processing system. The demosaicing processing unit uses computational methods to analyze pixel correlations in four directions and reconstruct missing color information, substituting physical optical filtering with algorithmic processing to achieve the same color moire suppression without resolution loss.
2Device complexity
If a Bayer array color filter is used with green pixels in check pattern and red and blue arranged line-sequentially, then the structure is simple and widely used, but low-frequency coloring (color moire) occurs due to folding of high frequency signals
Solution Approach 1:
The patent implements feedback through correlation analysis in the demosaicing process. By calculating correlations between pixels in horizontal, vertical, and oblique directions, the system determines the dominant frequency direction and adjusts the interpolation accordingly, creating a feedback loop that adapts to the local image characteristics to suppress color moire.
Solution Approach 2:
The patent extends the analysis from simple horizontal and vertical correlations to include oblique directions (NE and NW). This adds dimensional complexity to the correlation analysis, allowing the system to detect and suppress color moire patterns that occur at various orientations, not just horizontal or vertical stripes.
3Loss of information
If complex demosaicing processing is performed to interpolate missing color pixels from surrounding pixels, then a multi-channel image is obtained, but reproduction characteristics of high-frequency image signals deteriorate
Solution Approach 1:
The patent implements dynamic demosaicing processing that adapts to local image characteristics. The system calculates correlations in four directions for each pixel and dynamically determines the optimal interpolation direction based on the strongest correlation, allowing the processing to adapt to varying frequency patterns throughout the image rather than using a fixed algorithm.
Solution Approach 2:
The patent applies local quality by performing direction-specific correlation analysis for each pixel or small region. Instead of applying a uniform demosaicing algorithm across the entire image, the system determines the dominant frequency direction locally and applies appropriate interpolation only in that direction, preserving high-frequency details while suppressing color moire in the specific local context.
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 configuration effectively suppresses false color moire in high-frequency sections while maintaining or improving resolution, simplifying image processing, and reducing the complexity of demosaicing, thereby enhancing image reproduction accuracy.
Implementation Method 1
a lens 1 for forming an optical image of the object 200
Implementation Method 2
a first photodetecting element 11 for detecting the optical image with a first spectral sensitivity
Data Source
Figure 1~2
Figure 3A~3B
Figure 4~5
AI summary
Provided is a single-plate color imaging element including color filters in a predetermined color filter array arranged on a plurality of pixels formed by photoelectric conversion elements arranged in horizontal and vertical directions. The color filter array of the color imaging element includes a predetermined basic array pattern P including filters of all R, G, and B colors arranged in all lines in the horizontal and vertical directions, and the basic array pattern P is repeatedly arranged in the horizontal and vertical directions. Particularly, the G filters are arranged to include sections where two or more G filters are adjacent to each other in each direction (four directions) of horizontal, vertical, and oblique (NE, NW) directions in the basic array pattern, and pixel values of G pixels corresponding to the adjacent G filters allow determining a correlation of luminance in the four directions at minimum pixel intervals.