Vibration correction control circuit for correcting displacement of an optical axis due to vibration including camera shake and image pickup apparatus equipped therewith
View Patent ↗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. A control unit samples a plurality of amplitude values of an acceleration signal during a predetermined unit period in the panning state or the tilting state. When an average value of the sampling values exists nearer to zero than a predetermined basic threshold value, it is judged that the panning state or the tilting state is terminated.
1. A vibration correction control circuit for correcting displacement of an optical axis due to vibration applied to an image pickup apparatus, the circuit comprising:
an integrating circuit configured to integrate an angular velocity signal output from a vibration detection element for detecting the vibration and generate a shift amount signal indicating a shift amount of the image pickup apparatus; and
a control unit configured to determine the termination of a panning mode or tilting mode in the image pickup apparatus, the control unit sampling the amplitude value of the angular velocity signal a plurality of times within a predetermined unit period during the panning or tilting mode and determining the termination of the panning or tilting mode when the average value of the sampling values lies closer to zero than a predetermined basic threshold, wherein
when a divisor used to compute the average value is defined as n (n is a positive even number), the control unit adds one-half of the total of the sampling values in the preceding unit period and the total of n/2 of the sampling values in the current unit period and divides the resulting value by n, so as to obtain the average value in the current unit period.
2. A vibration correction control circuit of for correcting displacement of an optical axis due to vibration applied to an image pickup apparatus, the circuit comprising:
an integrating circuit configured to integrate an angular velocity signal output from a vibration detection element for detecting the vibration and generate a shift amount signal indicating a shift amount of the image pickup apparatus; and
a control unit configured to determine the termination of a panning mode or tilting mode in the image pickup apparatus the control unit sampling the amplitude value of the angular velocity signal a plurality of times within a predetermined unit period during the panning or tilting mode and determining the termination of the panning or tilting mode when the average value of the sampling values lies closer to zero than a predetermined threshold for determination of termination, wherein,
when the amplitude value of an angular velocity signal sampled in the panning or tilting mode lies farther from zero than a threshold for detection of an abnormal value set to be farther from zero than the threshold for determination of termination, the control unit stops the determination of the termination of the panning or tilting mode until the amplitude value gets closer to zero than the threshold for detection of an abnormal value.
3. The vibration correction control circuit of claim 2 , wherein:
the integrating circuit is configured with a digital filter which includes a register for retaining an integrated value to be set as an amplitude value of the shift amount signal;
the control unit provides control to gradationally decrease the absolute value of an integrated value retained in the register in the panning or tilting mode; and,
when the average value lies closer to zero than the basic threshold and, in addition, the integrated value retained in the register is a predetermined value or less, the control unit determines that the panning or tilting mode has terminated, and, in the other situations, the control unit does not determine the termination of the panning or tilting mode.
4. A vibration correction control circuit for correcting displacement of an optical axis due to vibration applied to an image pickup apparatus, the circuit comprising:
an integrating circuit configured to integrate an angular velocity signal output from a vibration detection element for detecting the vibration and generate a shift amount signal indicating a shift amount of the image pickup apparatus; and
a control unit configured to determine the termination of a panning mode or tilting mode in the image pickup apparatus, the control unit sampling the amplitude value of the angular velocity signal a plurality of times within a predetermined unit period during the panning or tilting mode and determining the termination of the panning or tilting mode when the average value of the sampling values lies closer to zero than a predetermined threshold for determination of termination, wherein
the integrating circuit is configured with a digital filter which includes a register for retaining an integrated value to be set as an amplitude value of the shift amount signal;
the control unit provides control to gradationally decrease the absolute value of an integrated value retained in the register in the panning or tilting mode; and
when the average value lies closer to zero than the threshold for determination of termination and, in addition, the integrated value retained in the register is a value for determination of a lens position or less, the control unit determines that the panning or tilting mode has terminated, and, in the other situations, the control unit does not determine the termination of the panning or tilting mode.
5. A vibration correction control circuit for correcting displacement of an optical axis due to vibration applied to an image pickup apparatus, the circuit comprising:
an integrating circuit configured to integrate an angular velocity signal output from a vibration detection element for detecting the vibration and generate a shift amount signal indicating a shift amount of the image pickup apparatus; and
a control unit configured to determine the termination of a weak vibration correction mode, which is a state between a panning mode or tilting mode in which correction processing of the vibration is invalidated and a vibration correction mode in which the correction processing is validated, and which is a state in which the sensitivity of the correction processing is set to be weaker than in the vibration correction mode, the control unit sampling the amplitude value of the shift amount signal a plurality of times within a predetermined unit period during the weak vibration correction mode and determining the termination of the weak vibration correction mode when the average value of the sampling values lies closer to zero than a predetermined threshold, wherein
when a divisor used to compute the average value is defined as n (n is a positive even number), the control unit adds one-half of the total of the sampling values in the preceding unit period and the total of n/2 of the sampling values in the current unit period and divides the resulting value by n, so as to obtain the average value in the current unit period.
6. The vibration correction control circuit of claim 5 , further comprising
a centering processing circuit configured to perform centering of a shift amount signal output from the integrating circuit toward zero, wherein
the control unit samples the amplitude value of a shift amount signal output from the centering processing circuit.
7. An image pickup apparatus, comprising:
a lens;
an image pickup element;
a drive element configured to drive the lens or the image pickup element;
a position detection element configured to detect the position of the lens or the image pickup element;
a vibration detection element configured to detect vibration; and
the vibration correction control circuit of claim 1 , the vibration correction control circuit controlling the drive element to correct the position of the lens or the image pickup element, on the basis of a position signal output from the position detection element and the shift amount signal.