Image Stabilization Control Circuit Non-Linearity Correction
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Solution Overview
Problem
Conventional image stabilization control circuits face challenges in accurately correcting for hand-shake blur due to non-linear input/output characteristics of position-detecting elements, which vary between elements, making it difficult to configure a corrective circuit with fixed logic circuitry and limiting processing speed.
Innovation Solution
An image stabilization control circuit that includes a microcomputer with a memory to store correction functions for each position-detecting element, allowing for digital processing and accurate displacement control of moveable components to compensate for vibration-induced image displacement, using a current position signal, shake displacement signal, and target position signal to generate a displacement control signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed logic circuitry is used for correction, then device complexity is reduced, but measurement precision deteriorates due to inability to accommodate non-linear characteristics of position-detecting elements
Solution Approach 1:
The patent creates a digital copy of the correction function stored in a memory device, which contains pre-calculated correction values for non-linear characteristics. This allows the system to store complex correction data without using complex hardware circuitry, resolving the contradiction between device complexity and measurement precision.
Solution Approach 2:
The patent replaces traditional analog correction circuits with a digital processing system. Instead of using fixed logic circuitry to correct non-linearities, the system uses a processor to read correction data from memory and apply it digitally, achieving both simplicity in hardware design and high precision in measurement.
2Productivity
If processing speed is increased to correct hand-shake blur accurately, then image quality improves, but device complexity increases due to more sophisticated correction circuits
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing correction values in the memory device before actual image capture. The correction functions are prepared in advance, allowing the processor to simply retrieve and apply pre-computed values during operation, achieving high processing speed without requiring complex real-time calculation circuits.
Solution Approach 2:
The correction functions are stored as digital data copies in memory, allowing rapid retrieval and application during image processing. This digital copying approach enables fast processing speeds while keeping the hardware structure simple, as the complex correction logic is embedded in software/data rather than hardware.
3Measurement precision
If correction functions are stored in memory for each position-detecting element, then measurement precision improves, but volume of the control circuit increases
Solution Approach 1:
The patent stores correction functions as digital data copies in memory rather than using physical correction circuits for each element. This digital storage approach allows precise correction of each position-detecting element's characteristics while occupying minimal space, as the correction data can be stored compactly in memory rather than requiring proportional hardware resources.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise correction of hand-shake-derived blur by addressing the non-linearity of position-detecting elements, improving processing speed, and reducing the size of the control circuit, while accommodating inconsistencies in element characteristics, thus enhancing image quality.
Implementation Method 1
The position-detecting element 102, which may be a Hall element, generates an induced current according to the absolute position of the lens 108, and outputs a voltage signal
Implementation Method 2
The vibration-detecting element 106 may be a gyro-sensor. The vibration-detecting element 106 generates an angular velocity signal corresponding to the vibration imparted to the image pickup apparatus
Implementation Method 3
The lens-driving element 104 may be a voice coil motor. The image stabilization control circuit 100 adjusts the magnitude of a voltage applied to the lens-driving element 104 and thereby controls the position of a moveable coil in the voice coil motor
Data Source
AI summary
The accuracy of servo control of a corrective lens in an image stabilization control circuit is prevented from decreasing due to non-linear characteristics of a position-detecting element. A signal representing a component of vibration of an image pickup apparatus is generated based on an angular velocity signal from a vibration-detecting element. A microcomputer corrects the vibration component signal according to a predetermined correction function and generates a target position signal representing a target position of the lens. A position-detection signal based on an output from the position-detecting element is compared with the target position signal, and the position of the lens is servo-controlled. The correction function is set so that the characteristics of variation of the target position signal relative to the target position will be the same as the characteristics of variation of the position-detection signal relative to the actual position of the lens.