Flicker Correction via Phase Displacement Detection
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Solution Overview
Problem
Existing image-processing methods for flicker reduction in image-acquisition devices with X-Y address systems, such as CMOS sensors, face challenges in accurately correcting flicker components due to phase displacement errors caused by variations in power-supply frequency and image-acquisition frame rate, leading to potential misdetection and overcorrection.
Innovation Solution
An image-processing device and method that includes a flicker detecting portion, a phase-displacement detecting portion, and an infinite-impulse-response correction-signal combining portion to generate a second flicker correction signal by combining past and current flicker correction signals with phase displacement correction, effectively removing flicker from input images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional flicker correction methods are used, then flicker components can be reduced, but phase displacement errors cause misdetection and overcorrection
Solution Approach 1:
The patent implements feedback by detecting phase displacement between current and past flicker correction signals, then using this detected phase displacement to correct the current flicker correction signal. This closed-loop feedback mechanism adjusts the correction process based on actual phase differences, preventing misdetection and overcorrection while maintaining effective flicker removal.
Solution Approach 2:
The patent performs preliminary action by storing past flicker correction signals and pre-calculating phase displacement before applying correction to the current frame. By preparing correction data in advance and adjusting for phase displacement beforehand, the system avoids real-time calculation errors and prevents overcorrection.
2Stability of the object's composition
If past flicker correction signals are used for correction, then temporal stability improves, but phase displacement causes incorrect correction
Solution Approach 1:
The patent changes the parameter of phase alignment by detecting and compensating for phase displacement between past and current flicker correction signals. By adjusting the phase parameter dynamically, the system maintains temporal stability from past signals while ensuring correction accuracy is not compromised by phase misalignment.
3Adaptability or versatility
If frame rate variations occur, then flicker correction becomes inaccurate, but power-supply frequency changes cause phase shifts
Solution Approach 1:
The patent applies dynamics by making the flicker correction process adaptive to changing conditions. The system dynamically detects phase displacement caused by power-supply frequency changes or frame rate variations and adjusts the correction signal accordingly. This dynamic adaptation allows accurate flicker correction even when operating conditions change.
Data Source
AI summary
An image-processing device is provided with: a flicker detecting portion that detects a flicker component in an input image signal for each frame and that generates a first signal; a storing portion that stores the generated first signal for a plurality of latest continuous frames; a phase-displacement detecting portion that selects, from the stored past first flicker correction signals, the first signal having substantially the same phase as the most-recent first signal, and that detects a phase displacement level with respect to the most-recent first signal; a phase-displacement correcting portion that corrects the selected past first signal on the basis of the detected phase displacement level; an infinite-impulse-response combining portion that generates a second signal by combining, at a predetermined ratio, the corrected past first signal and the most-recent first signal; and a flicker correcting portion that corrects the input image signal on the basis of the generated second signal.