Image stabilization control circuit
View Patent ↗An image stabilization control circuit controls an optical element driving element that moves an optical element provided in an imaging apparatus based on an output signal of a vibration detection element provided in the imaging apparatus. The image stabilization control circuit includes a high-pass filter that removes a low-frequency component from an output signal of the vibration detection element. A movement amount calculation circuit calculates a movement amount of the imaging apparatus based on an output signal of the high-pass filter. A servo circuit generates a correction signal for correcting the position of the optical element based on an output signal of the movement amount calculation circuit and outputs the correction signal to the optical element driving element. The movement amount calculation circuit includes a digital filter circuit and a register. The digital filter circuit performs filter processing based on a filter coefficient stored in the register.
1. An image stabilization control circuit, comprising:
an analog-digital conversion circuit configured to convert an analog signal output by a gyro sensor to a digital signal;
a high-pass filter configured to remove a low-frequency component from a signal output by the analog-digital conversion circuit;
a movement amount calculation circuit configured to calculate a movement amount of an imaging apparatus based on an output signal of the high-pass filter;
a centering processing circuit configured to subtract a predetermined value from the movement amount output from the movement amount calculation circuit so as to prevent an optical element from approaching a limit point of a movable range, and output a result signal to a servo circuit;
a servo circuit configured to generate a correction signal for correcting a position of the optical element based on the output result signal of the centering processing circuit and output the correction signal to an optical element driving element;
a pan/tilt determination circuit configured to compare an output signal of the high-pass filter with a predetermined threshold and determine whether a panning operation or a tilting operation is performed based on a result of comparison; and
an amplification circuit configured to amplify the output signal of the high-pass filter and change an amplification rate according to the result determined by the pan/tilt determination circuit, and
wherein each of the high-pass filter, the movement amount calculation circuit, the centering processing circuit, the pan/tilt determination circuit, and the amplification circuit is implemented not by a microcomputer but by a logic circuit and includes a digital filter circuit and a register;
the digital filter circuit performs filter processing based on a filter coefficient stored in the register; and
the optical element provided in the imaging apparatus is moved based on the output signal of the gyro sensor provided in the imaging apparatus.
2. The image stabilization control circuit according to claim 1 , wherein the servo circuit generates the correction signal based on a sum of an output signal of a position detection element configured to detect the position of the optical element and an output signal of the movement amount calculation circuit.
3. The image stabilization control circuit according to claim 2 , wherein the servo circuit includes a digital filter circuit and a register, and the digital filter circuit performs filter processing based on a filter coefficient stored in the register.
4. An imaging apparatus comprising:
a gyro sensor configured to detect vibration of an imaging apparatus;
an optical element;
a position detection element configured to detect a position of the optical element;
an optical element driving element configured to drive the optical element; and
an image stabilization control circuit configured to control the optical element driving element based on an output signal of the gyro sensor,
wherein the image stabilization control circuit comprises:
an analog-digital conversion circuit configured to convert an analog signal output by the gyro sensor to a digital signal;
a high-pass filter configured to remove a low-frequency component from an output signal of the analog-digital conversion circuit;
a movement amount calculation circuit configured to calculate a movement amount of the imaging apparatus based on an output signal of the high-pass filter;
a centering processing circuit configured to subtract a predetermined value from the movement amount output from the movement amount calculation circuit so as to prevent an optical element from approaching a limit point of a movable range, and output a result signal to a servo circuit; and
a servo circuit configured to generate a correction signal for correcting the position of the optical element based on the output result signal of the centering processing circuit and output the correction signal to the optical element driving element;
a pan/tilt determination circuit configured to compare an output signal of the high-pass filter with a predetermined threshold and determine whether a panning operation or a tilting operation is performed based on a result of comparison; and
an amplification circuit configured to amplify the output signal of the high-pass filter; and
wherein each of the high-pass filter, the movement amount calculation circuit, the centering processing circuit, the pan/tilt determination circuit, and the amplification circuit is implemented not by a microcomputer but by a logic circuit and includes a digital filter circuit and a register, and the digital filter circuit performs filter processing based on a filter coefficient stored in the register;
the optical element provided in the imaging apparatus is moved based on the output signal of the gyro sensor provided in the imaging apparatus, and
the amplification circuit is configured to change an amplification rate according to the result determined by the pan/tilt determination circuit.