One-Dimensional Filter False Color Reduction in Image Processing
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Solution Overview
Problem
Existing image processing methods for single-plate type color cameras generate false colors at edges due to color interpolation, which are difficult to eliminate without compromising image sharpness or requiring heavy processing.
Innovation Solution
An image processing method that converts image data into luminance and color-difference signals, using one-dimensional or two-dimensional filters to select pixels and exclude maximum and minimum values, determining the target pixel value from the remaining values to reduce or eliminate false colors effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If color interpolation processing is performed on image data from a single-plate type color camera, then complete color information can be obtained at each pixel, but false colors are generated at edge parts where pixel values change largely
Solution Approach 1:
The patent segments the image processing into distinct stages: color interpolation processing followed by false color reduction processing. By separating these functions and applying targeted processing to specific regions (edge parts), the patent resolves the contradiction between obtaining complete color information and eliminating false colors.
Solution Approach 2:
The patent applies false color reduction processing specifically to edge parts where pixel values change largely, rather than uniformly processing the entire image. This localized approach preserves color accuracy in general areas while eliminating false colors at edges, resolving the contradiction between maintaining color information and removing false colors.
2Object-generated harmful factors
If an optical low-pass filter is inserted before the image pickup sensor to reduce false color, then false color is reduced, but high spatial frequency components are cut, lowering image sharpness and resolution
Solution Approach 1:
The patent replaces the mechanical/optical low-pass filter with a digital signal processing approach. By performing false color reduction through computational methods (calculating differences between interpolated and original values, applying filtering algorithms), the patent eliminates false colors without the side effects of optical filtering, thus preserving image sharpness and resolution.
3Object-generated harmful factors
If saturation at the edge part is lowered to make false color less visible, then false color becomes less noticeable, but processing complexity increases and correct information may be lost
Solution Approach 1:
The patent changes the processing approach from simple saturation reduction to a more sophisticated method involving calculation of pixel value differences, identification of edge parts, and selective false color reduction. This parameter-based approach targets false colors more precisely without unnecessarily complicating processing or losing correct information.
4Object-generated harmful factors
If heavy processing is applied to eliminate false color accurately, then false color is reduced effectively, but processing time and computational load increase significantly
Solution Approach 1:
The patent applies partial processing by focusing false color reduction only on edge parts where pixel values change largely, rather than processing the entire image uniformly. This selective approach reduces false colors effectively while minimizing processing time and computational load by excluding non-edge areas from intensive processing.
Data Source
AI summary
An image processing method is provided for performing false color reduction processing on a color-difference signal acquired after performing color interpolation processing on image data taken in by a color image pickup sensor, wherein the false color reduction processing uses a one-dimensional filter for selecting N (N≧4) pixels which are continuous in a row direction including a target pixel and determines a pixel value of the target pixel from the pixel values that remain when maximum and minimum pixel values are excluded from the pixel values of the pixels selected by the one-dimensional filter. This enables effective reduction or elimination of a false color generated at an edge part by the color interpolation processing.