Image Shake Correction Offset Reference Calculation
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Solution Overview
Problem
Conventional image shake correction techniques face challenges in accurately correcting low-frequency components of camera shake, leading to deterioration in correction precision and instability immediately after power-on due to low-frequency noise and temperature drift, resulting in unsuitable correction and reduced performance.
Innovation Solution
An image shake correcting apparatus that includes a shake detecting unit, a calculating unit with an offset removing unit and a reference value calculating unit, which calculates an offset reference value to subtract from the shake detection signal, allowing for stable image shake correction across a wide frequency band immediately after power-on.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-pass filter is used to remove low-frequency components from the sensor output signal, then offset removal is improved, but low-frequency noise and temperature drift cause deterioration in correction precision
Solution Approach 1:
The patent applies preliminary action by calculating and storing the offset reference value immediately after power-on before normal operation begins. This pre-calculated offset value is then used during operation to compensate for low-frequency components, preventing rather than reacting to the harmful effects of temperature drift and noise on correction precision.
2Measurement precision
If the cut-off frequency of the high-pass filter is set low to improve correction for low-frequency components, then correction performance is improved, but the swing-back signal becomes large and convergence time increases
Solution Approach 1:
The patent calculates the offset reference value in advance during a dedicated period after power-on, before panning or tilting operations occur. This preliminary calculation allows the system to use a lower cut-off frequency during normal operation without suffering from prolonged convergence time, as the offset compensation is already in place.
Solution Approach 2:
The patent applies preliminary anti-action by pre-calculating and storing the offset reference value that will counteract the swing-back signal effects. By having this compensation ready in advance, the system can maintain low cut-off frequency for better correction performance without experiencing extended convergence delays when panning or tilting occurs.
3Speed
If image shake correction is performed immediately after power-on, then responsiveness is improved, but stability is reduced due to temperature drift and low-frequency noise
Solution Approach 1:
The patent performs preliminary calculation of the offset reference value during a brief initialization period after power-on. This allows the main image shake correction function to start immediately with stable, pre-calculated offset compensation, achieving both responsiveness (immediate correction) and stability (accurate offset removal) simultaneously.
Data Source
AI summary
An image shake correcting apparatus includes a calculating unit that calculates an image shake correction amount by acquiring a shake detection signal output from a shake detecting unit. A shake correcting unit corrects an image shake in accordance with the calculated image shake correction amount. An offset removing unit removes an offset component from the shake detection signal. A reference value calculating unit calculates an offset reference value from the shake detection signal. The calculating unit causes the offset removing unit to remove an offset component from the shake detection signal to thereby calculate the image shake correction amount from a start of an operation of the shake detecting unit until the reference value calculating unit calculates the offset reference value, and the calculating unit calculates the image shake correction amount from a signal obtained by subtracting the offset reference value from the shake detection signal.