Shake Detection Signal Processing for Image Blur Correction
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Solution Overview
Problem
In camera systems with interchangeable lenses, differences in shake detection performance between the lens and camera body can lead to reduced image blur correction accuracy due to varying noise characteristics, particularly in stationary and high-frequency conditions.
Innovation Solution
A shake detection apparatus with first and second detectors, a signal processing unit that includes filters with specific transmission characteristics based on noise density ratios, and an output unit combining processed signals from both detectors to generate a unified shake detection signal, effectively compensating for performance differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both lens and camera body perform image blur correction using their respective shake detection means, then the effective range for blur correction is expanded, but the correction accuracy is lowered due to differences in detection performance and noise characteristics
Solution Approach 1:
The patent segments the frequency spectrum into multiple bands (low frequency band and high frequency band) and assigns different detection signals to different bands based on their noise characteristics. Specifically, one shake detection means is used for low frequency components while another is used for high frequency components, allowing each detector to operate in its optimal frequency range where it exhibits lower noise levels.
Solution Approach 2:
The patent applies local quality by optimizing the use of each shake detection means for specific frequency regions where they demonstrate superior performance. Instead of uniformly using both detectors across all frequencies, the system selectively applies each detector's output to specific frequency bands where that detector exhibits lower noise characteristics, thereby maximizing overall correction accuracy.
2Adaptability or versatility
If shake detection means with different noise characteristics are used in lens and camera body, then the detection coverage is improved, but the noise output increases and detection precision deteriorates
Solution Approach 1:
The patent dynamically selects which shake detection signal to use based on frequency content. The system continuously analyzes the frequency characteristics of shake movements and dynamically assigns the appropriate detection signal for each frequency component, allowing the system to adapt to varying shake conditions and maintain optimal detection precision across different frequency ranges.
Solution Approach 2:
The patent changes the parameter of signal selection based on frequency characteristics. By identifying the noise characteristics of each shake detection means across different frequency ranges, the system changes which detection signal is applied at each frequency band, optimizing the overall detection precision by utilizing each detector's strengths in its optimal frequency range.
Data Source
AI summary
An image pickup apparatus is provided with an image blur correction apparatus that corrects image blur of a captured image by using a shake detection signal that has been detected by a shake detection unit. A controller for image blur correction generates a first signal obtained by multiplying an output signal of the shake detection unit by a first correction ratio gain. A second signal is generated by multiplying the sum of the output signal of the shake detection unit that has passed through a low-pass filter and the output signal of the shake detection unit that has passed through a high-pass filter by a second correction ratio gain. A target generating unit generates a target value signal for image blur correction based on the sum of the first and second signals and drives the shake correction unit.