Vibration Correction Circuit Digital Filter Noise Reduction
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Solution Overview
Problem
Existing vibration correction systems in digital cameras are prone to oversensitivity when the integrated value of the acceleration signal is small, leading to unnatural movement of the image in the finder due to noise, especially when the input value is large, causing the lens to react excessively to vibration detection signals.
Innovation Solution
A vibration correction control circuit that includes an integrating circuit and a control unit with a digital filter, which adjusts the shift amount signal by computing the variation between current and previous integrated values, and applies an adjustment value to bring the variation close to zero, thereby reducing sensitivity and improving accuracy during low-integrated-value conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lens shift amount is computed by integrating the acceleration signal, then the vibration correction function operates, but the lens reacts oversensitively when the integrated value is small, causing unnatural image movement
Solution Approach 1:
The patent changes the processing parameters of the acceleration signal by applying a digital filter (low-pass, high-pass, or band-pass) to modify the frequency characteristics. This transforms the raw acceleration signal into a filtered signal that reduces noise impact while maintaining vibration correction effectiveness, thereby resolving the oversensitivity issue at low integrated values
Solution Approach 2:
The patent introduces a digital filter as an intermediary component between the vibration detection element and the integrating circuit. This intermediary processes the acceleration signal to remove harmful noise components before integration, preventing the noise from causing unnatural image movement while preserving the essential vibration information
2Quantity of substance
If noise is mixed into the acceleration signal, then the integrated value varies, but the lens moves unnaturally in the finder
Solution Approach 1:
The patent converts the harmful noise in the acceleration signal into a beneficial filtered signal by applying digital filters. The low-pass filter removes high-frequency noise, the high-pass filter removes low-frequency drift, and the band-pass filter isolates the useful vibration frequency range, thereby transforming noise contamination into clean vibration data that improves image stabilization
Data Source
AI summary
An integration circuit integrates an angular velocity signal outputted from a vibration detection element and generates a shift amount signal indicating the shift amount of an imaging device. The integration circuit is formed by a digital filter, which includes a register for holding an accumulation value serving as a shift amount signal. A control unit acquires an accumulation values held in the register at a predetermined interval and obtains a change amount between the accumulation value previously obtained and the accumulation value currently obtained. When the change value exceeds a predetermined threshold value, the control unit subtracts a correction value from the currently obtained accumulation value so that the value approaches zero and resets the obtained value in the register.