Lens Distortion Correction in Imaging Devices Using Luminance Interpolation
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Solution Overview
Problem
Existing imaging devices face challenges in performing image processing without resolution degradation, particularly when using a small-scale circuit and interpolating RAW data from color filters with regularly arranged 2*2 pixel sets, which leads to degradation due to long distances between same-color pixels.
Innovation Solution
An imaging device that includes a same-color interpolation unit, luminance signal generation and interpolation units, a lens distortion characteristics table/data unit, and a correction unit to generate and correct interpolation signals, allowing for lens distortion correction and reducing circuit scale by using luminance signals correlated with RAW signal frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If distortion correction processing is performed on RAW image data before YC processing, then the size of memory for storing data is reduced, but the resolution is degraded due to long distances between same-color pixels
Solution Approach 1:
The patent divides the distortion correction process into multiple stages: first performing correction on luminance components (Y) separately, then combining with chrominance components. This segmentation allows using closer same-color pixels for interpolation while maintaining memory efficiency, resolving the contradiction between reduced memory size and maintained resolution.
Solution Approach 2:
The patent applies different interpolation strategies to different components: luminance components use one interpolation method while chrominance components use another. By treating Y and UV/Wv components differently with appropriate interpolation coefficients, the system maintains resolution while reducing memory requirements.
2Device complexity
If same-color pixels are used for interpolation, then circuit scale is reduced, but resolution is degraded due to long distances between same-color pixels
Solution Approach 1:
The patent segments the interpolation process by separating luminance and chrominance components. The luminance component interpolation uses different coefficients than chrominance component interpolation, allowing optimal use of same-color pixels for luminance while maintaining chrominance quality, thus reducing circuit scale without sacrificing resolution.
Solution Approach 2:
The patent changes interpolation parameters (coefficients) based on component type and position. By adjusting interpolation coefficients dynamically for different components and locations, the system achieves high resolution with minimal circuit scale, resolving the contradiction between circuit complexity and resolution.
Data Source
AI summary
An imaging device is provided with a lens distortion correction function that requires less circuit scale and does not degrade image resolution.The imaging device having the lens distortion correction function is provided which includes a same-color interpolation unit that generates a lens distortion-corrected interpolation signal by using a same-color pixel in an image signal from an imaging element, a luminance signal generation unit that generates a luminance signal from the image signal from the imaging element, a first luminance signal generation unit and a second luminance signal generation unit that use the luminance signal generated by the luminance signal generation unit to generate a lens distortion-corrected interpolation signal, a lens distortion characteristics table data unit that holds information of coordinates after lens distortion characteristics correction in a memory, a coordinate/interpolation coefficient setting unit that individually generates interpolation coefficients for correcting lens distortion for each of the same-color interpolation unit, the first luminance interpolation unit, and the second luminance interpolation unit on the basis of information from the lens distortion characteristics table data unit, and a correction unit that outputs a lens distortion-corrected interpolation signal by correcting the signal from the same-color interpolation unit on the basis of a ratio between the interpolation signal generated by the first luminance interpolation unit and the interpolation signal generated by the second luminance interpolation unit.