Image stabilization control circuit
View Patent ↗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.
1. An image stabilization control circuit used for an image pickup apparatus comprising
a vibration-detecting element,
a vibration-compensating mechanism having a moveable component, and
a position-detecting element for detecting a driving position of the moveable component, displacement of the moveable component reducing the effect of image-capture displacement resulting from vibration of the image pickup apparatus; wherein
the image stabilization control circuit comprises:
a current position signal-generating part for generating a current position signal, which is a digital signal, for indicating a current position of the moveable part, based on a signal outputted by the position-detecting element;
a shake displacement signal-generating part for generating a shake displacement signal, which is a digital signal, in accordance with a degree of shake displacement of the image pickup apparatus, based on a signal outputted by the vibration-detecting element, using a sampling rate lower than the current position signal;
a target position signal-generating part for correcting the shake displacement signal based on a pre-set correction function and generating a target position signal for indicating a target position for the moveable component; and
a displacement control signal-generating part for generating a displacement control signal for instructing the vibration-compensating mechanism to displace the moveable component from the current position to the target position, based on the target position signal and the current position signal;
the target position signal-generating part comprises:
a memory part for storing, as the correction function, a corresponding relationship between a value before a correction and a corrected value of the shake displacement signal configured based on input/output characteristics of the position-detecting element indicating a relationship between the driving position of the moveable component and the current position signal; and
a processor for correcting the shake displacement signal and calculating the target position signal from the corrected shake displacement signal, based on the correction function.