Pixel Interpolation Using Four-Direction Correlation Analysis
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Solution Overview
Problem
Existing pixel interpolation methods in digital cameras, which rely on correlations in vertical and horizontal directions, may lead to misinterpolation due to limited consideration of diagonal directions, especially in imaging devices with pixels arrayed in non-traditional patterns like octagonal or dodecagonal arrangements.
Innovation Solution
A pixel interpolation method that evaluates correlations in four directions (two pairs of perpendicular directions) and performs interpolation based on strong correlations, using weight assignments proportional to these correlations to improve accuracy, particularly effective for devices with diagonal pixel patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel interpolation is performed using only vertical and horizontal correlations, then the interpolation process is simple, but misinterpolation occurs in diagonal regions and accuracy is reduced
Solution Approach 1:
The patent extends the interpolation process from two dimensions (vertical and horizontal) to four dimensions by adding two diagonal directions. This dimensional expansion allows the system to capture correlation information in all major directions around a target pixel, preventing misinterpolation in diagonal regions while maintaining a systematic and manageable process through the use of correlation values and weighted averaging.
2Measurement precision
If pixel interpolation is performed using correlations in multiple directions including diagonals, then interpolation accuracy is improved, but the complexity of the interpolation method increases
Solution Approach 1:
The patent introduces correlation values as quantitative parameters to measure the strength of pixel relationships in different directions. By calculating correlation values for vertical, horizontal, and diagonal directions, and then using these parameters to determine weighted averages, the system systematically manages the increased complexity while achieving superior interpolation accuracy through data-driven direction selection.
3Measurement precision
If pixel data is interpolated using traditional RGB color filter with single-chip arrangement, then the imaging device structure is simple, but color interpolation accuracy is limited due to spatial separation of color components
Solution Approach 1:
The patent performs correlation analysis and determines the optimal interpolation direction before actually computing the interpolated pixel values. By预先 evaluating the correlation strengths in vertical, horizontal, and diagonal directions, the system selects the most appropriate direction(s) for interpolation, ensuring high accuracy for RGB color filters while maintaining computational efficiency through preliminary directional assessment.
Data Source
AI summary
Correlation values in the vertical direction, horizontal direction and two diagonal directions are obtained in a pixel signal of RGB Bayer pattern. The correlation values are calculated using G signals. Between a first pair of the vertical and horizontal directions and a second pair of the two diagonal directions, one pair having a greater correlation difference is selected. Then, a direction having a stronger correlation is selected in the selected pair having a greater correlation difference, and pixel interpolation is performed in the selected direction. Alternatively, pixel interpolation is performed following assignment of weights in two directions of the selected pair having a greater correlation difference in accordance with the proportion of their correlations.