Chromatic Aberration Detection from RAW Data Correlation
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Solution Overview
Problem
Conventional methods for detecting chromatic aberration of magnification in electronic cameras are hindered by false color noise and low pass filtering, which complicates accurate detection, especially when color interpolation is performed first, and require pre-recorded standard patterns for correction, making it difficult and costly to account for varying photographic conditions.
Innovation Solution
An image processing device and program that directly detect chromatic aberration from RAW data by calculating correlation between color components at different pixel positions, removing pixel interval effects, and adjusting magnification to correct for aberration without relying on standard patterns or color interpolation, allowing detection in general RAW data and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If color interpolation is performed first to generate an image composed of color components aligned at each pixel, then chromatic aberration detection can be performed using conventional techniques, but false color noise is generated at the edge of the image which cannot be discriminated from chromatic aberration of magnification
Solution Approach 1:
Instead of performing color interpolation first and then detecting chromatic aberration (conventional approach), the patent inverts the sequence by detecting chromatic aberration directly from RAW data before color interpolation. This is achieved by calculating correlation between color components at different pixel positions in the RAW data, thereby avoiding the generation of false color noise that would interfere with detection.
2Object-affected harmful factors
If chrominance low pass filtering is applied to reduce false color noise during color interpolation, then false color noise is reduced, but unevenness of color shift due to chromatic aberration of magnification is caused which makes detection more difficult
Solution Approach 1:
The patent extracts the chromatic aberration detection process from the color interpolation pipeline. By detecting chromatic aberration directly from RAW data using correlation calculation between color components at different pixel positions, the method separates the detection function from the interpolation and filtering processes, thereby avoiding the unevenness problem caused by chrominance LPF while still eliminating false color noise through the correlation-based detection approach.
3Measurement precision
If standard patterns with pre-recorded reference information are used to detect chromatic aberration of magnification, then detection can be performed, but it becomes difficult and costly to account for varying photographic conditions such as different lenses and zoom positions
Solution Approach 1:
The patent creates a universal chromatic aberration detection method that works across different photographic conditions without requiring condition-specific standard patterns. By using correlation calculation between color components at different pixel positions in general RAW data, the method achieves multi-functionality that adapts to various lenses, zoom positions, and imaging conditions, eliminating the need for costly pre-recorded reference information for each condition.
4Adaptability or versatility
If general RAW data is used instead of standard patterns, then adaptability to various photographic conditions is improved, but detection accuracy may be reduced due to lack of reference information
Solution Approach 1:
The patent replaces the mechanical approach of using physical standard patterns and pre-recorded reference information with a computational approach based on correlation calculation. By substituting the reference-based method with a correlation-based method that operates directly on color components in RAW data, the system achieves both adaptability to various conditions and high detection accuracy without requiring external reference materials.
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
Enables precise detection of chromatic aberration without false color noise interference and unevenness, applicable to various photographic conditions, reducing processing load and improving image quality by correcting chromatic aberration directly from RAW data.
Implementation Method 1
a detecting section which detects a color shift amount by calculating correlation between two color components included in the RAW data and determines according to the color shift amount the chromatic aberration of magnification of the optical system used for capturing the image
Data Source
AI summary
An image processing device has an input section and a detecting section. The input section receives RAW data composed of color components arranged in each pixel in a predetermined pattern. The detecting section detects the color shift amount by calculating the correlation between two color components included in the RAW data and determines the chromatic aberration of magnification of the optical system used for capturing the image from the color shift amount.