Shake amount detection device and imaging device
A shake amount detection device includes an acceleration sensor. A vibration period detector detects a vibration period during which vibration that becomes a predetermined acceleration is applied to a body. A velocity variation estimation unit estimates a first movement velocity which is a component velocity due to an attitude movement of the body during the vibration period. A velocity calculator calculates a second movement velocity that is a velocity of the body and corrects the second movement velocity in a case of the vibration period as a detection result of the vibration period detector. A shake amount calculator calculates an image blur correction amount relative to the vibration applied to the body, based on the second movement velocity corrected by the velocity calculator.
1. A shake amount detection device comprising:
an acceleration sensor configured to detect an acceleration which is applied to a body;
a vibration period detector configured to detect a vibration period during which vibration that becomes a predetermined acceleration is applied to the body;
a velocity variation estimation unit configured to estimate a first movement velocity which is a component velocity due to an attitude movement of the body during the vibration period, based on the acceleration detected by the acceleration sensor;
a velocity calculator configured to calculate a second movement velocity that is a velocity of the body, based on the acceleration, and to correct the second movement velocity, based on the first movement velocity estimated by the velocity variation estimation unit, in a case of the vibration period as a detection result of the vibration period detector; and
a shake amount calculator configured to calculate an image blur correction amount, which is an image movement amount occurring due to the attitude movement of the body, relative to the vibration applied to the body, based on the second movement velocity corrected by the velocity calculator.
2. The shake amount detection device of claim 1 , wherein the velocity variation estimation unit includes:
an interpolation unit configured to interpolate and calculate an acceleration during the vibration period by using accelerations before and after the vibration period, the acceleration being a component due to the attitude movement of the body during the vibration period; and
an integration arithmetic unit configured to estimate the first movement velocity during the vibration period by integrating the interpolated acceleration.
3. The shake amount detection device of claim 2 , wherein the interpolation unit is configured to execute the interpolation by an interpolation curve generated by using three or more accelerations before and after the vibration period.
4. The shake amount detection device of claim 3 , wherein the interpolation unit is configured to calculate the interpolation curve by using accelerations before the vibration period, the number of the accelerations being equal to or greater than the number of accelerations after the vibration period.
5. The shake amount detection device of claim 2 , further comprising a controller configured to control precision of interpolation arithmetic of interpolating the acceleration during the vibration period.
6. The shake amount detection device of claim 5 , wherein the controller is configured to control the precision of the interpolation arithmetic in accordance with at least one of an image magnification and a shutter speed.
7. The shake amount detection device of claim 1 , wherein the velocity variation estimation unit is configured to determine whether or not to execute estimation of the velocity variation, in accordance with a length of a continuation period of the vibration period, the continuation period being a time from a start of the vibration period detected by the vibration period detector to an end of the vibration period.
8. The shake amount detection device of claim 1 , wherein the velocity variation estimation unit includes:
a first integration unit configured to integrate the acceleration detected by the acceleration sensor;
an extraction unit configured to extract an acceleration due to vibration based on an operation of a movable component which is different from the body itself, from among accelerations detected by the acceleration sensor; and
a second integration unit configured to integrate the acceleration extracted by the extraction unit,
wherein the velocity variation is estimated from a difference between an integration result of the first integration unit and an integration result of the second integration unit.
9. The shake amount detection device of claim 8 , wherein the extraction unit includes a high-pass filter having a cutoff frequency which is higher than an upper limit value of frequencies of vibration of the body due to camera shake and is lower than a lower limit value of frequencies of vibration based on the operation of the movable component.
10. The shake amount detection device of claim 1 , wherein the velocity is a translational velocity.
11. The shake amount detection device of claim 1 , wherein the vibration of the predetermined threshold or more is vibration due to movement of a shutter.
12. An imaging device comprising:
the shake amount detection device of claim 1 ; and
a shutter,
wherein the vibration period detector is configured to detect the vibration period, based on a control signal of the shutter.