Moire Detection in Image Processing Using Temporal Motion Analysis
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Solution Overview
Problem
Existing image processing technologies face challenges in distinguishing moire from actual high-frequency components, leading to a trade-off between maintaining resolution and eliminating moire, as they often rely on frequency-based differences that include high-frequency components.
Innovation Solution
An image processing apparatus with a moire detection unit that identifies pixel regions with different motion patterns between images at different times, generating detection information to differentiate moire from actual image patterns, regardless of frequency, and a moire reduction unit that performs low-pass filter processing based on this information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency-based moire detection methods are used, then moire can be detected in low-frequency portions, but high-frequency components of actual images cannot be distinguished from moire
Solution Approach 1:
The patent applies dynamics by utilizing temporal changes in image data across multiple frames. Instead of relying solely on spatial frequency analysis, the invention detects motion characteristics of pixel regions between frames. Moire patterns exhibit different motion behavior compared to actual image content, allowing discrimination through temporal dynamics while preserving high-frequency resolution.
Solution Approach 2:
The patent transitions from two-dimensional spatial frequency analysis to three-dimensional analysis by adding the time dimension. By analyzing pixel region characteristics across multiple frames, the invention creates a temporal dimension that enables distinction between moire and actual high-frequency components, resolving the trade-off between moire detection and resolution preservation.
2Object-affected harmful factors
If optical low-pass filters are used to suppress moire, then moire generation is reduced, but image resolution and sense of sharpness deteriorate
Solution Approach 1:
The patent replaces the mechanical/optical low-pass filter with a digital signal processing approach. Instead of physically filtering light before it reaches the sensor, the invention uses post-capture image processing to detect and remove moire patterns based on their distinctive motion characteristics, thereby preserving the full resolution capability of the imaging sensor.
Solution Approach 2:
The patent introduces motion analysis as an intermediary mechanism between image capture and moire removal. By analyzing temporal changes in pixel regions and identifying those with abnormal motion patterns characteristic of moire, the system can selectively process only moire-affected areas, preserving overall image resolution while eliminating moire artifacts.
3Measurement precision
If two optical systems with different resolutions are used to detect moire, then moire can be detected from resolution differences, but device complexity increases
Solution Approach 1:
The patent makes the single imaging sensor perform multiple functions by utilizing temporal sequences of images. The same sensor that captures high-resolution images is also used to detect moire patterns through frame-to-frame comparison, eliminating the need for separate detection systems while maintaining full resolution capability.
Solution Approach 2:
The patent changes the parameter being analyzed from spatial resolution differences (requiring multiple optical systems) to temporal motion characteristics (achievable with a single sensor). By examining how pixel regions change over time across frames, the invention detects moire without requiring multiple optical systems with different resolutions.
Data Source
AI summary
An image processing apparatus is provided with a moire detection unit that detects a pixel region with a different motion out of a pixel region in which the same motion as a motion of a subject is assumed as a change in an in-frame position between images at different times, and generates detection information of moire.