Multispectral Image Correction for Phase-Induced Color Shifts
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Solution Overview
Problem
Existing image correction methods, such as band image shifting and linear interpolation, struggle to effectively reduce color shifts caused by phase differences in pushbroom-type image acquisition systems, which are common in aircraft and satellite imaging.
Innovation Solution
An image correction device and method that acquires position differences between band images and uses pixel values from a reference band image to correct pixel values in an object band image, ensuring accurate alignment and reducing color shifts by overlapping pixels and applying appropriate relationships between pixel values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If band image shifting and linear interpolation are used to correct color shifts, then general alignment is improved, but color shift caused by phase difference remains
Solution Approach 1:
The patent changes the interpolation parameter from simple linear interpolation to an optimized interpolation that considers phase differences between bands. By modifying the interpolation calculation to account for sub-pixel shifts and phase relationships, the system achieves both accurate alignment and effective color shift reduction simultaneously.
Solution Approach 2:
The patent introduces an intermediary calculation step that determines optimal interpolation weights based on phase difference measurements. This intermediary process acts as a bridge between the raw band images and the final corrected image, enabling the system to compensate for phase-induced color shifts while maintaining alignment accuracy.
2Productivity
If simple interpolation processing is applied, then processing speed is maintained, but color shift caused by phase difference cannot be reduced
Solution Approach 1:
The patent performs preliminary measurement of phase differences between bands before the interpolation process. By pre-calculating the phase shift parameters, the system can then apply targeted interpolation corrections without requiring complex real-time calculations, thus maintaining processing speed while improving color shift reduction effectiveness.
3Measurement precision
If band images are shifted by position difference, then spatial alignment is improved, but color discrepancy due to phase shift persists
Solution Approach 1:
The patent applies different interpolation strategies to different regions of the image based on local phase difference characteristics. By analyzing phase shifts locally and applying region-specific correction parameters, the system achieves both accurate spatial alignment and consistent color reproduction across the entire image.
Data Source
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AI summary
An image correction device is configured to acquire band images obtained by imaging a subject; by using at least one of the band images as a reference band image and at least one of the rest of the band images as an object band image, acquire a position difference between the object band image and the reference band image; by using a pixel of the object band image as an object pixel and each of pixels of the reference band image that overlap the object pixel when the object pixel is shifted by the position difference as a corresponding pixel, create a corrected band image that holds a pixel value of light on the object band image at the pixel position of the reference band image, on the basis of a relationship between pixel values of the corresponding pixels; and output the corrected band image.