JP2010096938A - Optical apparatus having image-blur correcting function and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately correct image blurs caused by camera shake on macrophotography, without having to depend on the exposure time. <P>SOLUTION: The radius of gyration of shake that is regarded as angle shake is determined, respectively, in a plurality of frequencies in frequency components of shift shake. Here, the exposure time is detected, and on the basis of a result of the detection, combining of the radii of gyration is performed by weighting the radius of gyration so that the final correction amount is decided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an anti-vibration system that corrects image blur to prevent deterioration of a captured image due to blur, and in particular, an optical apparatus having an image blur correction function that can perform good image blur correction even under shooting conditions with a large shooting magnification. It relates to the control method.

  Blur applied to a photographing device such as a camera often causes image blurring and causes image degradation of the photographed image.

  In order to reduce the influence of the blur, there is an image blur correction technique for detecting a blur using an angular velocity meter and reducing an image blur on the image sensor surface by moving a part of the lens.

  The so-called angle blur that can be detected by this technology among the blurs applied to the photographing device has a great influence on most photographing conditions, so this technology is currently installed in various optical devices as an effective image blur correction function. .

  However, in close-up shooting (shooting conditions with a high shooting magnification), image degradation caused by so-called shift blur, which cannot be detected only by an angular velocity meter and is applied in a direction parallel or perpendicular to the optical axis of the camera, cannot be ignored.

  For example, if the shooting condition is as close as 20 cm to the subject, or if the subject is located at about 1 m and the focal length of the shooting optical system is very large (for example, 400 mm), the shift blur is positively detected. Need to be corrected.

  In Patent Document 1, an accelerometer that detects the acceleration of the camera body is provided, shift blur is obtained from the second-order integration of the output of the accelerometer, angular blur is obtained from the integration of the angular velocity meter output provided separately, and blur correction is performed using these synthesized signals. There is disclosure to do.

  However, the output of the accelerometer is susceptible to environmental changes such as disturbance noise and temperature, particularly in the frequency range of camera shake. These instability factors are further expanded by second-order integration, and there is a problem that it is difficult to correct shift blur with high accuracy.

  Further, Patent Document 2 discloses that shift blur is determined as angle blur when the center of rotation is located away from the camera.

  In this method, an angular velocity meter and an accelerometer are provided, and the rotational radius and angle of angular blur are obtained from their outputs, and blur correction is performed.

In this method, since the radius of rotation can be calculated from the output of the first-order integral of the output of the accelerometer, the above instability factors of the accelerometer can be reduced.
JP 7-225405 A JP 2005-114845 A

  In the method of obtaining shift blur using the rotational radius of angular blur, it is necessary to accurately determine the rotational radius.

  However, the blur applied to the camera usually has a plurality of frequency components, and the radius of rotation is often different at each frequency.

  Therefore, there is a problem that accurate correction is difficult unless the rotation radius corresponding to each frequency is obtained. If only the radius of rotation obtained from a single frequency is used, shift blurring of other frequency components cannot be corrected accurately, resulting in a large correction remaining.

  Further, which frequency component blurring effect becomes greater depends on the exposure time of the image sensor.

  When the exposure time is long, the low frequency blur greatly affects, and when the exposure time is short, the high frequency blur largely affects.

  In view of the above problems, an object of the present invention is to realize an image stabilization system capable of performing an optimum blur correction according to an exposure time when shooting at a close distance (shooting conditions with a high shooting magnification).

  According to the first aspect of the present invention, there is provided an optical apparatus having an image blur correction function, the correction amount determining means for determining a correction amount necessary for correcting the image blur, and based on the correction amount. Blur correction means for correcting the image blur, and the correction amount determination means obtains information on the exposure time of the optical instrument, and sets the rotation radius of blur applied to the optical instrument at different frequencies, respectively. When the value of the exposure time is smaller than a predetermined value, the rotation radius at the higher frequency among the plurality of frequencies is given a higher weight than the rotation radius at the lower frequency, and the value of the exposure time is the predetermined value. When the value is larger than the value, the weight of the rotation radius at the lower frequency among the plurality of frequencies is given a higher weight than the rotation radius at the higher frequency, and the correction amount is determined based on the result. And wherein the Rukoto.

  According to a fourth aspect of the present invention, there is provided a control method for an optical apparatus having an image blur correction function necessary for correcting an image blur based on a result obtained by the weighting step. An exposure time acquisition step for acquiring exposure time information; a rotation radius acquisition step for acquiring rotation radius of blur applied to the optical device at a plurality of different frequencies; and whether or not the value of the exposure time is smaller than a predetermined value. An exposure time determination step for determining the exposure time, and when the value of the exposure time is smaller than a predetermined value, the rotation radius at a higher frequency among the plurality of frequencies is given a higher weight than the rotation radius at a lower frequency, and the exposure When the time value is larger than the predetermined value, the rotation radius at the lower frequency of the plurality of frequencies is compared with the rotation radius at the higher frequency. A weighting step of attaching a large weight to be characterized as having a a determination step of determining a correction amount required to correct the image blur based on the results obtained by the weighting step.

  It is possible to realize an image stabilization system capable of performing a suitable blur correction according to the exposure time under shooting conditions with a high shooting magnification.

  An example of an optical apparatus having an image blur correction function that can be used in the present invention will be described.

  FIG. 1 is a plan view of a single-lens reflex camera, and FIG. 2 is a side view thereof.

  The anti-vibration system mounted on the interchangeable lens 101 mounted on the camera has a shake indicated by arrows 103p and 103y (hereinafter referred to as angle shake) and a shake indicated by arrows 104pa and 104ya (hereinafter referred to as shift shake) with respect to the optical axis 102. To compensate for blur.

  In the camera body 105, 105a is a release button, 105b is a mode dial (including a main switch), 105c is a retractable strobe, and 105d is a camera CPU. Reference numeral 106 denotes an image sensor, and 107p and 107y are angular velocity detecting means (hereinafter referred to as angular velocity meters) for detecting angular blur around the arrows 103p and 103y (the arrows 107pa and 107ya are the respective detection sensitivity directions).

  Reference numerals 104p and 104y denote acceleration detecting means (hereinafter referred to as accelerometers) for detecting shift blurs indicated by arrows 104pa and 104ya, respectively. Reference numeral 108 denotes a coil that performs blur correction by taking both angle blur and shift blur into account by driving the blur correction lens 108a freely in the directions of arrows 108p and 108y in FIGS.

  Here, the outputs of the angular velocity meters 107p and 107y and the accelerometers 104p and 104y are calculated by the lens CPU 109 to obtain a correction amount necessary for image blur correction.

  That is, in this embodiment, the lens CPU 109 functions as a correction amount determination unit.

  The actuator 110 drives the blur correction lens 108a via the coil 108 in accordance with the correction amount in synchronization with the half-press of the release button 104a (hereinafter, S1: an operation for instructing photometry and focusing for preparation for shooting).

  That is, in this embodiment, the actuator 110, the coil 108, and the shake correction lens 108a serve as shake correction means.

  Here, in this embodiment, so-called optical image stabilization, in which the blur correction lens is moved in a plane perpendicular to the optical axis based on the calculated correction amount, is used as the blur correction unit. However, the correction method based on the correction amount is not limited to optical image stabilization, and may be a method as disclosed in Japanese Patent Laid-Open No. 2008-048013.

  That is, the object of the present invention can also be achieved by using electronic image stabilization that reduces the influence of blurring by changing the cut-out position of each shooting frame output by the image sensor, or by correcting with a combination thereof. .

  When electronic image stabilization is used, the camera shake correction unit is a camera CPU and an image sensor, and the combination of optical image stabilization and electronic image stabilization adds the camera CPU and image sensor to the configuration of this embodiment.

  In this embodiment, the shift blur is obtained by regarding the angle blur when the center of rotation is at a location away from the camera.

  FIG. 3 is a diagram showing shift blur Y (104 pb) and angle blur θ (103 pb) applied to the camera.

  Although FIG. 3 shows only shift blur in the pitch direction, only the pitch direction will be described here because the yaw direction can be calculated in the same manner.

  The shift blur Y (104 pb) and angle blur θ (103 pb) at the principal point position of the photographing optical system, and the rotation radius L (301 p) when the blur rotation center O (302 p) is determined can be expressed by the following equations. .

The rotation radius L (301p) is the distance from the rotation center O (302p) to the accelerometer 104p.
L = Y / tan θ (1)
L = V / tan ω (2)
Equation (1) is obtained by calculating the rotation radius L (301) from the shift blur Y (104a) calculated by integrating the output of the accelerometer 104 twice and the angular blur θ (103b) obtained by integrating the output of the angular velocity meter 107 once. This is the calculated formula.

  Equation (2) is an equation for obtaining the turning radius L (301) from the velocity V calculated by integrating the output of the accelerometer 104 once and the angular velocity ω which is the output of the angular velocity meter 107, and the equation (1), The rotation radius L (301) can be obtained by any method of (2).

Here, since the blur angle and the angular velocity are small, the equations (1) and (2) can be approximated by the following equations.
L = Y / θ (3)
L = V / ω (4)
Equation (3) is a rotation radius L obtained from the displacement Y obtained by integrating the output of the accelerometer 104 twice and the angle θ obtained by integrating the output of the angular velocity meter 107 once. Equation (4) is obtained by calculating the rotation radius L from the velocity V obtained by integrating the output of the accelerometer 104 once and the angular velocity ω which is the output of the angular velocity meter 107. The equations (3) and ( The turning radius can be obtained by any method of 4).

Here, the blur δ occurring on the imaging surface of the imaging optical system will be described. Based on the shift blur Y at the principal point position of the photographing optical system, the angular blur θ of the photographing optical system, the focal length f of the photographing optical system, and the photographing magnification β, the blur δ generated on the imaging surface is obtained by the following equation (5).
δ = (1 + β) fθ + βY (5)
Here, the first term on the right side is the angle blur amount, and the second term on the right side is the shift blur amount. The focal length f and the imaging magnification β in the first term on the right side are obtained from the zoom and focus information of the imaging optical system, and the angle θ is obtained from the integration result of the angular velocity meter. Therefore, the block diagram of FIG. Thus, angle blur correction can be performed.

  In the second term on the right side, the shift blur amount can be obtained from the shift blur Y, which is the twice integrated value of the accelerometer, and the photographing magnification β obtained from the zoom and focus information.

However, in the present invention, the blur correction is performed on the blur δ that is rewritten from the formula (5) as the following formula (6).
δ = (1 + β) fθ + βLθ (6)
That is, with respect to shift blurring, instead of using shift blur displacement Y obtained by integrating the accelerometer output twice, the rotational radius L is obtained once by equation (4).

  Then, the shift blur correction amount is calculated from the rotation radius L, the angular velocity blur θ, and the shooting magnification β obtained from the zoom and focus information.

  As described above, shift blur includes a plurality of frequency components, and the radius of rotation is often different for each of them.

  Therefore, in this embodiment, in determining the correction amount for correcting the image blur due to the shift blur, the rotation radii of the plurality of frequencies are acquired. In each example described below, the rotation radii are acquired at three different frequencies. Further, a plurality of rotation radii obtained are combined to determine a correction amount.

  A feature of the present embodiment is that, when the rotation radii are combined, the rotation radii of the respective frequency components are weighted according to the exposure time. Here, the weighting means that, when a plurality of components are combined, calculation is performed by multiplying each component by a coefficient based on a certain index.

  Hereinafter, examples will be shown and described in detail.

  FIG. 4 is a block diagram of the image stabilization system in the present embodiment. This block diagram shows the configuration of blur (pitch direction) generated in the vertical direction of the camera, and a similar block is also provided for blur (yaw direction) generated in the horizontal direction of the camera. Since these two blocks basically have the same configuration, only the pitch direction will be described here.

  First, correction of angular blur, which is also disclosed in the prior art, will be described.

  The output of the angular velocity meter 107 is taken into the lens CPU 109. The output is input to a high-pass filter (hereinafter referred to as HPF) 401, and the DC component is cut.

  The output of the HPF 401 is integrated by the integration filter 402 and converted into an angle output θ. Note that these HPF and integral filter processing are obtained by calculating the output of the quantized angular velocity meter 107p in the lens CPU 109, and can be realized by a known difference equation or the like. In addition, it can be realized by an analog circuit using a capacitor or a resistor before being input to the lens CPU 109.

  Here, the cutoff frequencies of the HPF 401 and the integration filter 402 will be described. Since the blur frequency range is generally 1 Hz to 10 Hz, the cut-off frequency is a first-order filter characteristic that cuts off frequency components of 0.1 Hz or less away from the blur frequency range.

  The output of the integration filter 402 is input to the sensitivity adjustment unit 403. The sensitivity adjustment unit 403 adjusts the output of the integration filter 202 based on the output of the zoom and focus information 404 input to the lens CPU 109 from a focus encoder or zoom encoder (not shown), and calculates a target value for angle blur correction. To do.

  The reason why the sensitivity adjustment unit 403 performs the adjustment is that the sensitivity of the blur correction on the camera image plane with respect to the blur correction stroke of the coil 105 changes due to a change in the optical state of the lens such as zoom and focus.

  The output of the sensitivity adjustment unit 403, which is a target value for angle blur correction, is output from the lens CPU 109 as a target value for blur correction.

  The correction amount output from the lens CPU 109 is input to the coil 108 by the actuator 110, and the blur correction lens 108a is driven to perform the blur correction. In the present invention, the output of the sensitivity adjustment unit 403 that is the target value of the angle blur correction and the output of the output correction unit 420 that is the target value of the shift blur correction described later are added by the lens CPU 109 to the actuator 110. Is output.

  Next, the shift blur correction block will be described.

  The output of the angular velocity meter 107p is taken into the lens CPU 109. Then, the output is input to the HPF 401, and the DC component is cut. The phase of the output of the HPF 401 is adjusted by the phase adjustment filter 405. Here, the phase adjustment by the phase adjustment filter 405 is performed in order to match the phase with the output of the integration filter 210 described later. Since the integration filter 410 has a cutoff frequency of 0.1 Hz, the phase adjustment filter 405 is also an HPF of 0.1 Hz. The output of the phase adjustment filter 405 is input to angular velocity BPFs 406, 407, and 408, which are band pass filters (hereinafter referred to as BPF) as band extraction means, and the frequency components of the bands set in the respective filters are extracted and output. .

  In this embodiment, the lens CPU 109 which is the correction amount determining unit also serves as the band extracting unit, but an analog BPF or the like may be used as the band extracting unit.

  The output of the accelerometer 104 is input to the HPF 409, and the DC component is cut. The output of the HPF 409 is input to the integration filter 410 and converted into speed.

  At this time, the cutoff frequency of the HPF 409 is 0.1 Hz which is the same as that of the HPF 401, and the cutoff frequency of the integration filter 410 is 0.1 Hz which is the same as that of the phase adjustment filter 405 as described above.

  The integration filter 410 is constituted by a low-pass filter (hereinafter referred to as LPF). Further, since the phase adjustment filter 405 performs the HPF calculation by subtracting the LPF calculation result from the input, the phase of the integration filter 410 and the output match. The output of the integration filter 410 is input to the speeds BPF 411, 412, and 413, and a frequency component of a predetermined band having a certain set peak is output.

  Here, the first angular velocity BPF 406 and the first velocity BPF 411 output signals having the same transmission band and a peak of 2 Hz.

  The second angular velocity BPF 407 and the second velocity BPF 412 output a signal having the same transmission band and a peak of 5 Hz, and the third angular velocity BPF 408 and the third velocity BPF 413 output a signal having the same transmission band and a peak of 10 Hz.

  Outputs of the first angular velocity BPF 406 and the first velocity BPF 411 are input to the first turning radius calculation means 414. Similarly, the outputs of the second angular velocity BPF 407 and the second velocity BPF 412 are input to the second turning radius calculation means 415. Further, the outputs of the third angular velocity BPF 408 and the third velocity BPF 413 are inputted to the third turning radius calculating means 416, and the respective turning radii are calculated by the equation (4). The outputs of the turning radius calculation means 414, 415, and 416 are input to the composition ratio correction means 419.

  Next, the exposure time acquisition unit 417 outputs information on the acquired exposure time to the calculation change unit 418.

  The calculation change means 418 outputs a signal for reflecting the result of the exposure time acquisition means to the composition of the rotation radius to the composition ratio correction means 419. Within the composition ratio correction means 419, the composition ratio of the outputs of the turning radius calculation means 414, 415, and 416 is adjusted and output to the output correction means 420. Processing in the synthesis ratio correction unit 419 will be described later.

  The output correction unit 420 calculates the shift blur amount Y from the angle θ output from the integration filter 402 and the rotation radius L output from the synthesis ratio correction unit 419.

  Further, the shift blur amount Y is corrected based on the output of the zoom and focus information 404, and a shift blur correction target value is calculated.

  The correction amount that is the output of the output correction unit 420 is added to the angle blur correction target value that is the output of the sensitivity adjustment unit 403, and is output from the lens CPU 109 as a correction amount.

  The output of the lens CPU 109 is input to the coil 108 by the actuator 110, and the blur correction lens 108a is driven to perform the blur correction.

A calculation method in the synthesis ratio correction unit 419 will be described. Assuming that the rotation radii obtained by the rotation radius calculation means 414, 415, and 416 are L_2 Hz, L_5 Hz, and L_10 Hz, respectively, the final rotation radius L obtained by the composition ratio correction means 419 is expressed as follows.
L = 0.2 × L_2 Hz + 0.3 × L_5 Hz + 0.5 × L_10 Hz (7)
A coefficient applied to each rotation radius in Expression (7) represents weighting for each frequency component. In this way, stable shift blur correction can be performed by using the rotation radius of each frequency on average.

  However, the weighting ratio appropriate for the blur correction varies depending on the exposure time set in the photographing.

  FIG. 6 is a waveform showing the remaining shake correction amount at each exposure time when the weighting coefficient applied to each rotation radius is changed. In FIG. 6, the horizontal axis represents the exposure time t, the vertical axis represents the shake amount V, and A represents the shake waveform before correction.

  B is a residual shake waveform after shake correction weighted on the high frequency side, for example, as in Expression (7).

C is a residual shake waveform after shake correction weighted on the low frequency side, for example, as in equation (8).
L = 0.5 × L_2 Hz + 0.3 × L_5 Hz + 0.2 × L_10 Hz (8)
Further, t1 and t2 indicate exposure times, and the exposure end timing when the exposure starts at time t = 0. That is, t1 indicates the exposure end timing when the exposure time is short, and t2 indicates the exposure end timing when the exposure time is long. Further, the shake amounts of the waveform B and the waveform C at the exposure time t1 are V1 and V2, respectively, and the shake amounts of the waveform B and the waveform C at the exposure time t2 are V4 and V3, respectively.

  Here, when the exposure time is t1, since V2> V1, the amount of remaining shake is smaller when the waveform B, that is, the high frequency side is weighted. Further, when the exposure time is t2, V4> V3, so that the amount of remaining shake is smaller when the waveform C, that is, the low frequency side is weighted.

  The shakes that have a large effect on the camera can be roughly classified into the following two shakes. One is a high-frequency, small-amplitude blur having a center of rotation in the hand and arm that are relatively close to the camera. The other is a low frequency, large amplitude blur centered somewhere else in the entire body that is relatively far from the camera.

  When the exposure time is short, high-frequency blur has a greater effect than slowly changing low-frequency blur. On the other hand, when the exposure time is long, a low frequency blur having a large amplitude has a great influence.

  Therefore, when the exposure time is long, it can be said that better correction can be performed by weighting the low frequency side.

  Therefore, in the present embodiment, the exposure time acquisition unit 417 acquires the exposure time, and the weighting is changed according to the exposure time, so that more appropriate parallel blur correction can be performed.

  A flow of communication from the camera to the lens side including communication of data necessary for implementation of the present embodiment is shown in the flowchart of FIG.

  When an operation is performed on the camera 104 side, serial communication is performed to the lens via the CPU 104d in the camera 104, and the lens CPU 109 in the lens 101 performs serial communication processing.

  The serial communication process is performed by an interrupt process. Then, it is possible to determine the release button half-press, the release button full-press, exposure time (shutter speed), camera model, and the like by decoding the communication data.

  In step 100, an instruction (command) from the camera is analyzed, and the process branches to a process corresponding to each instruction.

  In step 101, since the focus drive command is received, in step 102, the speed of the focus lens drive motor is set according to the target drive pulse number, and focus lens drive is started.

  In Step 103, since the aperture drive command is received, in order to drive the aperture based on the transmitted aperture drive data, the drive pattern of the stepping motor is set in Step 104, and the set drive pattern is output to the stepping motor. Drive the aperture.

  In step 105, since the camera lens status communication is received, in step 106, the lens focal length information, camera shake correction operation state, etc. are transmitted to the camera, or the camera status state (release switch state, shooting mode, exposure). Time). The exposure time information from the camera 104 used in this embodiment is acquired by the exposure time acquisition means 417 at this step.

  In step 107, there are other instructions, such as lens focus sensitivity data communication and lens optical data communication, and those processes are also performed in step 108.

  Next, processing performed by the lens CPU 109 for blur correction will be described with reference to the flowchart of FIG. Here, although only the pitch direction blur is shown, the yaw direction is the same.

  Blur correction is performed by timer interruption processing that occurs at regular intervals. In this embodiment, step 400 is an angular velocity detection step, step 401 is an acceleration detection step, step 406 is a velocity acquisition step, and steps 407 to 412 are band extraction steps.

  Further, steps 413 to 415 are a turning radius acquisition step, step 416 is an exposure time determination step, steps 417 and 418 are weighting steps, and step 419 is a determination step.

  (Step 400) A / D converted signal of the angular velocity meter 107p is stored in a RAM area (not shown) set by VAD_DAT.

  (Step 401) A / D converted signal from the accelerometer 104p is stored in a RAM area (not shown) set by ACCAD_DAT.

  (Step 402) The signal VAD_DAT of the angular velocity meter 107p is inputted, and the HPF 401 performs calculation.

  (Step 403) Using the calculation result of step 402 as an input, the integration filter 202 performs integration calculation. The result is stored in a RAM area (not shown) set by DEG_DAT. DEG_DAT is a shake angle displacement signal.

  (Step 404) Using the calculation result of step 402 as an input, the phase adjustment filter 205 calculates the phase adjustment. This processing is performed in order to match the phase with the signal processing (HPF and integration) of the accelerometer 104p to be performed later.

  (Step 405) With ACCAD_DAT as an input, the HPF 209 performs an operation.

  (Step 406) The integration filter 210 performs integration calculation with the calculation result of step 405 as input. This calculation result is a signal representing the speed V of shift blur.

  (Step 407) Using the calculation result of step 404 as an input, the calculation is performed with the first angular velocity BPF 406 in which the transmittance peak is 2 Hz. The result is stored in a RAM area (not shown) set by W_BPF2HZ_DAT.

  (Step 408) Using the calculation result of step 404 as an input, the calculation is performed with the second angular velocity BPF 407 in which the transmittance peak is 5 Hz. This result is stored in a RAM area (not shown) set by W_BPF5HZ_DAT.

  (Step 409) Using the calculation result of step 404 as an input, the calculation is performed at the third angular velocity BPF 408 where the transmittance peak is 10 Hz. This result is stored in a RAM area (not shown) set by W_BPF10HZ_DAT.

  (Step 410) Using the calculation result of step 406 as an input, the calculation is performed at the first speed BPF 411 in which the transmittance peak is 2 Hz. This result is stored in a RAM area (not shown) set by V_BPF2HZ_DAT.

  (Step 411) Using the integration calculation result of step 406 as an input, the calculation is performed at the second speed BPF 412 where the transmittance peak is 5 Hz. This result is stored in a RAM area (not shown) set by V_BPF5HZ_DAT.

  (Step 412) Using the integration calculation result of step 406 as an input, calculation is performed at the third speed BPF 413 where the transmittance peak is 10 Hz. This result is stored in a RAM area (not shown) set by V_BPF10HZ_DAT.

  (Step 413) W_BPF2HZ_DAT and V_BPF2HZ_DAT are compared, and a rotation radius L_2Hz is obtained.

  (Step 414) W_BPF5HZ_DAT and V_BPF5HZ_DAT are compared, and a rotation radius L_5 Hz is obtained.

  (Step 415) W_BPF10HZ_DAT and V_BPF10HZ_DAT are compared to obtain a turning radius L_10Hz.

(Step 416) It is determined whether or not the exposure time T _V is equal to or less than a predetermined value T _VC . If T _VC follows the process proceeds to step _417, it is greater than _{T VC} proceeds to step 418.

(Step 417) Since the exposure time T _V is equal to or less than the predetermined value T _VC , the rotation radius L weighted to the high frequency is calculated.
L = 0.2 × L_2 Hz + 0.3 × L_5 Hz + 0.5 × L_10 Hz (7)
(Step 418) Since the exposure time T _V is larger than the predetermined value T _VC , the rotation radius L weighted to the low frequency is calculated.
L = 0.5 × L_2 Hz + 0.3 × L_5 Hz + 0.2 × L_10 Hz (8)
(Step 419) The following calculation is performed from the photographing magnification β calculated from the position of the zoom / focus 204, the focal length f, the blur angular displacement DEG_DAT calculated in Step 403, and the optical image stabilization sensitivity correction value α. Determine the correction amount. The calculation result is stored in a RAM area (not shown) set by SFTDRV.
α {(1 + β) × f × DEG_DAT + β × L × DEG_DAT}
(Step 420) A / D conversion is performed on the displacement signal of the blur correction lens, and the A / D result is stored in a RAM area (not shown) set by SFTPST.

  (Step 421) A feedback calculation (SFTDRV-SFTPST) is performed. The calculation result is stored in a RAM area (not shown) set by SFT_DT.

  (Step 422) The loop gain LPG_DT is multiplied by SFT_DT. The calculation result is stored in a RAM area (not shown) set by SFT_PWM.

  (Step 423) A phase compensation calculation is performed in order to obtain a stable control system.

  (Step 424) The calculation result of step 423 is output to the driver 104 as a shake correction drive signal to perform shake correction.

  As described above, in steps 416 to 419 in FIG. 5, when the exposure time is less than or equal to a predetermined value, the rotation radius L weighted to the high frequency is calculated, and when the exposure time is larger than the predetermined value, the low frequency is weighted. The turning radius L is calculated. This makes it possible to perform an appropriate shift blur correction according to the exposure time. The weighting calculation formula is not limited to the formulas (7) and (8). When the exposure time is short, a higher weight is given to the rotation radius in the high frequency range, and when the exposure time is longer, a greater weight is given to the rotation radius in the low frequency range. Any arithmetic expression may be used.

  In the present embodiment, the length of the exposure time is divided into two, that is, whether the value of the exposure time is less than the predetermined value or larger than the predetermined value, but this is not restrictive. That is, if the weight is divided into three or more and each weight is changed in accordance with the gist of the present invention, a further effect can be expected. The gist of the present invention is that when the exposure time is short, a higher weight is given to the turning radius in the high frequency range, and when it is long, a larger weight is given to the turning radius in the low frequency range.

  In this embodiment, an example of changing the weighting according to the exposure time has been shown. However, the present invention is not limited to the above, and it is desirable to apply an appropriate value according to the characteristics of the device.

  The characteristics of the device mentioned here are, for example, the weight, size, and shape of the camera and lens, and the focal length of the lens.

  Therefore, the weighting values shown in the present embodiment are only examples, and if the determination result of the exposure time detecting means is reflected, the final weighting values are determined in consideration of other parameters. It does not matter if it is done.

  The rotation radius may be calculated at each moment, or may be calculated from the amplitude of a waveform sampled at a predetermined sampling time.

  Furthermore, the rotation radius may be updated at each calculated moment, or may be averaged in time series (for example, moving average).

  The present invention is not limited to an image stabilization system for a digital single-lens reflex camera or a digital compact camera, but can also be installed in a photographing apparatus such as a digital video camera or a mobile phone.

The top view of the camera carrying the vibration isolating system in this invention. The side view of the camera carrying the anti-vibration system in this invention. Explanatory drawing of the rotation center of blurring. The block diagram of a present Example. The flowchart figure which shows the serial communication operation | movement by the side of an interchangeable lens. The flowchart of the control of a present Example. Remaining blur correction amount for each exposure time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Lens 102 Optical axis 103y Yaw direction angle blur 103p Pitch direction angle blur 104p Accelerometer 104pa Accelerometer detection direction 104pb Vertical detection direction 104y Accelerometer 104ya Accelerometer detection direction 104yb Lateral detection direction 105 Camera 105a Release switch 105b Mode dial 105c Retractable strobe 105d Camera CPU
105e Electronic finder 106 Image sensor 107p Angular velocity meter 107pa Detection direction of angular velocity meter 107y Angular velocity meter 107ya Detection direction of angular velocity meter 108 Coil 108a Blur correction lens 108y Blur correction lens drive direction 108p Blur correction lens drive direction 109 Lens CPU
110 Actuator

Claims (6)

An optical instrument having an image blur correction function,
Correction amount determining means for determining a correction amount necessary for correcting the image blur;
Blur correction means for correcting the image blur based on the correction amount,
The correction amount determining means acquires information on an exposure time of the optical instrument,
Obtaining a rotation radius of a blur applied to the optical device at a plurality of different frequencies,
When the value of the exposure time is smaller than a predetermined value, the rotation radius at a high frequency among the plurality of frequencies is given a higher weight than the rotation radius at a low frequency, and the value of the exposure time is larger than the predetermined value. In this case, the optical device is characterized in that a rotation radius at a low frequency among the plurality of frequencies is given a higher weight than a rotation radius at a high frequency, and the correction amount is determined based on the result. Furthermore, angular velocity detection means for detecting the angular velocity of the optical device,
Acceleration detecting means for detecting the acceleration of the optical device,
The correction amount determination means determines a speed of the optical device based on the acceleration information, and acquires a rotation radius of the blur based on a ratio of the angular speed and the speed at the plurality of frequencies. Item 2. The optical device according to Item 1. Furthermore, a band extracting means is provided,
The correction amount determining means acquires the turning radius obtained based on outputs obtained by extracting components of different frequencies from the outputs of the angular velocity detecting means and the acceleration detecting means by the band extracting means. The optical apparatus according to claim 1 or 2. A method for controlling an optical apparatus having an image blur correction function,
An exposure time acquisition step of acquiring information of an exposure time of the optical instrument;
A rotation radius acquisition step of acquiring a rotation radius of a blur applied to the optical instrument at each of a plurality of different frequencies;
An exposure time determination step of determining whether or not the value of the exposure time is smaller than a predetermined value;
When the value of the exposure time is smaller than a predetermined value, the rotation radius at a high frequency among the plurality of frequencies is given a higher weight than the rotation radius at a low frequency, and the value of the exposure time is larger than the predetermined value. A weighting step of weighting a turning radius at a low frequency among the plurality of frequencies higher than a turning radius at a high frequency;
A determining step for determining a correction amount necessary for correcting image blur based on the result obtained by the weighting step;
A method for controlling an optical apparatus, comprising:   An angular velocity detection step for detecting an angular velocity of the optical device, an acceleration detection step for detecting an acceleration of the optical device, and a speed acquisition step for acquiring the velocity of the optical device based on the information on the acceleration, 5. The method of controlling an optical apparatus according to claim 4, wherein the rotation radius calculation step acquires a rotation radius of the blur based on a ratio between the angular velocity and the velocity at the plurality of frequencies.   The turning radius obtaining step obtains the turning radius obtained based on outputs obtained by extracting components of different frequencies from the outputs of the angular velocity detecting step and the acceleration detecting step by a band extracting step, respectively. The method for controlling an optical apparatus according to claim 4 or 5.

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