Pseudo-Random Color Filter Array for Image Sensor Artifact Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current image acquisition systems, such as those using Bayer color filter arrays, face challenges in achieving high image quality due to the generation of visible artefacts during image reconstruction, which complicates the processing and increases hardware complexity, while random or pseudo-random arrangements of color filters can reduce artefacts but complicate interpolation.
Innovation Solution
A pseudo-random arrangement of color filters on the sensor surface, combined with a method for reconstructing images that optimizes the quality-complexity ratio, using luminance and chrominance decomposition, and adaptive interpolation based on gradient calculations, allows for reduced artefacts and simplified interpolation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a Bayer color filter array is used, then the sensor structure is simple and regular, but visible artifacts are generated during image reconstruction
Solution Approach 1:
The patent applies asymmetry by using a pseudo-random arrangement of color filters instead of the regular periodic Bayer pattern. This irregular distribution eliminates the coherent aliasing artifacts that occur with symmetric periodic patterns, while still maintaining a manageable reconstruction complexity through the specific pseudo-random structure.
Solution Approach 2:
The patent changes the spatial distribution parameter of the color filters from a periodic pattern to a pseudo-random pattern. This parameter change fundamentally alters the spectral aliasing behavior, reducing visible artifacts while keeping the reconstruction process computationally feasible.
2Manufacturing precision
If four photosites are used to reconstruct a single pixel, then artifact generation is reduced, but the number of useful pixels is reduced by a factor of four
Solution Approach 1:
The patent uses a pseudo-random arrangement that requires less than four samples per pixel for accurate reconstruction. By optimizing the filter distribution, the system achieves high-quality reconstruction with fewer photosites, thereby increasing the effective pixel count while maintaining image quality.
3Manufacturing precision
If a random arrangement of color filters is used, then spectral aliasing is reduced and artifacts are minimized, but interpolation complexity increases
Solution Approach 1:
The patent uses a pseudo-random pattern that can be generated by copying and tiling a base pattern across the sensor array. This approach simplifies the interpolation process because the regular tiling structure provides predictable relationships between neighboring pixels, reducing computational complexity compared to completely random arrangements.
Solution Approach 2:
The patent segments the sensor array into repeating base patterns of pseudo-random color filter arrangements. This segmentation creates a structured approach to interpolation where each segment follows the same statistical properties, simplifying the reconstruction algorithm while maintaining artifact reduction benefits.
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 quality while reducing the complexity of the reconstruction method and acquisition device, making it suitable for resource-constrained applications like mobile devices and improving the subjective perception of reconstructed images.
Implementation Method 1
each color filter is a transparent component that lets some light through and absorbs some, the spectral distribution of transparency defines the color of the filter
Implementation Method 2
Each photosite represents a photoelectric cell, this photosite being sensitive to the light intensity in a wavelength range (red, green or blue) which it translates by producing a small electric current
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3i
AI summary
The invention aims to solve the problem of eliminating the trade-off between the complexity of the digital image capture device and captured image reconstruction and the quality of the image. For this purpose, the invention provides a digital image capture sensor (18) including an array (16) of colour filters, which array comprises a plurality of identical basic patterns (70) which are replicated with no overlap, each basic pattern being formed by colour filters (72, 82, 84) which are pseudo-randomly arranged, such that each basic pattern (70) contains a variable pitch between two consecutive same-type colour filters in the horizontal and/or vertical directions of the basic pattern.