JP5462541B2 - Imaging apparatus and control method thereof - Google Patents

Imaging apparatus and control method thereof Download PDF

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JP5462541B2
JP5462541B2 JP2009167268A JP2009167268A JP5462541B2 JP 5462541 B2 JP5462541 B2 JP 5462541B2 JP 2009167268 A JP2009167268 A JP 2009167268A JP 2009167268 A JP2009167268 A JP 2009167268A JP 5462541 B2 JP5462541 B2 JP 5462541B2
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panning
data
value
offset
shake
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JP2011022352A (en
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賢一 宮迫
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キヤノン株式会社
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The present invention relates to an imaging apparatus that corrects shake (image shake) of a captured image due to movement of the imaging apparatus, and a control method thereof.

  In recent years, with the downsizing of an imaging apparatus and the increase in the magnification of a zoom lens, the movement of the imaging apparatus during exposure, which is called apparatus blurring or camera shake, has become a major cause of reducing the quality of captured images. For this reason, there has been proposed a shake correction device that reduces the influence of device shake on a captured image.

  On the other hand, there is an imaging technique such as panning that captures an image while intentionally moving the imaging device. It is not preferable to apply the shake correction without distinguishing between the intentional movement of the imaging device and the device shake. For this reason, it is known to determine whether the imaging device is intentionally moved or device shake, and to correct the sensitivity of shake correction according to the determination result.

For example, Patent Document 1 discloses that when it is determined that the imaging apparatus is panned, the response of the blur correction function to the frequency component of panning is suppressed.
For example, as an example of a shake correction device mounted on an imaging device, there is a configuration as shown in FIG. In the shake correction device 10, an angular velocity sensor 11 is attached to an imaging device main body (not shown) and detects a shake of the imaging device as an angular velocity. The DC cut filter 12 blocks the direct current (DC) component of the angular velocity signal output from the angular velocity sensor 11 and passes only the alternating current component, that is, the vibration component. The amplifier 13 amplifies and outputs the angular velocity signal output through the DC cut filter 12. The A / D (analog / digital) converter 14 digitizes and outputs the angular velocity signal amplified by the amplifier 13.

  The high-pass filter (high-pass filter: HPF) 15, the integrator 16, the focal length calculation circuit 17, and the panning control circuit 18 are executed by, for example, a microcomputer 20 that executes software stored in a nonvolatile memory (not shown). It is realized by doing.

  The HPF 15 blocks a low frequency component below the set low frequency cutoff frequency from among the digital angular velocity signal (angular velocity data) frequency components output from the A / D converter 14, and a high frequency component exceeding the low frequency cutoff frequency. Is output. The integrator 16 integrates the high frequency component of the angular velocity data output from the HPF 15 and outputs the integration result as angular displacement data. The focal length calculation circuit 17 detects the focal length of a zoom lens included in an imaging device (not shown). For example, the focal length calculation circuit 17 acquires the current zoom position of the zoom lens included in the imaging apparatus from the zoom encoder, and calculates the focal length (view angle) of the zoom lens from the zoom position, thereby detecting the focal length. . Then, the focal length calculation circuit 17 calculates blur correction data for correcting the blur of the optical axis of the image sensor from the focal length and the angular displacement data described above. The shake correction circuit 19 corrects the optical axis shake of the imaging apparatus according to the shake correction data.

  The blur correction circuit 19 may be an optical blur correction circuit that performs blur correction by driving the correction lens in a direction perpendicular to the optical axis and decentering the optical axis, or may move an area to be read from the image sensor. Thus, an electronic blur correction circuit that performs blur correction may be used. Alternatively, it may be a sensor shift type blur correction circuit that moves the image sensor in a plane perpendicular to the optical axis.

  The panning control circuit 18 determines whether the imaging device is panned (panning determination) based on the angular velocity data output from the A / D converter 14 and the angular displacement data output from the integrator 16. Specifically, for example, if the angular velocity data is equal to or greater than a predetermined threshold value, or if the angular displacement data (integration result) is equal to or greater than the predetermined threshold value even if the angular velocity data is less than the predetermined threshold value, the panning state is determined. To do.

  Then, the panning control circuit 18 performs panning control according to the result of the panning determination. In the panning control, first, the low frequency cut-off frequency of the HPF 15 is gradually increased to reduce the frequency region of the blur where the blur correction functions to the high frequency side. Further, the value of the time constant used for the integration calculation in the integrator 16 is gradually reduced. As a result, the shake correction position gradually moves to the center of the moving range, and the value of the angular displacement data output from the integrator 16 gradually approaches the reference value (a value that can be taken in the absence of shake).

On the other hand, when it is determined that the panning state is not established, the panning control circuit 18 gradually lowers the low-frequency cutoff frequency of the HPF 15 and gradually increases the value of the time constant used for the integration calculation in the integrator 16. . As a result, the low-frequency cutoff frequency of the HPF 15 and the value of the time constant used for the integration calculation in the integrator 16 are restored to the original state, and the panning control is released.
For example, Patent Document 1 discloses a method for controlling the HPF 15 and the integrator 16 during panning described above.

Japanese Patent No. 3186219

However, since the frequency band of the panning operation is very close to about DC to 1 Hz and the frequency band of camera shake or body shake is about 1 Hz to 10 Hz, the conventional technique disclosed in Patent Document 1 has the following problems. There is.
In other words, when it is determined that the panning state is established, the low frequency cutoff frequency of the HPF 15 and the time constant value in the integrator 16 are controlled to increase the attenuation of the signal of the panning frequency component. In addition, the attenuation amount of the signal of the frequency component of body shaking during walking is also increased. As a result, when the panning state is determined, the blur correction effect is lower than when the panning state is not determined.

The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an imaging apparatus capable of suppressing a reduction in blur correction effect even in a panning state and a control method thereof.

In order to achieve the above object, an imaging apparatus according to the present invention includes a shake detection unit that detects a shake, a calculation unit that calculates first image shake correction data based on an output of the shake detection unit, and a shake detection unit. Panning detecting means for detecting whether or not the panning operation is based on the output, offset value generating means for generating an offset value for subtraction from the first image blur correction data, and the panning detecting means And a shake correction unit that corrects the image blur using the second image blur correction data obtained by subtracting the offset value from the first image blur correction data. Data for returning the shake correction means approaching the correction end of the shake correction means to the correction center of the shake correction means. Values zooming speed is equal to or greater than the offset value is smaller than a predetermined value.

With such a configuration, according to the present invention, it is possible to provide an imaging apparatus capable of suppressing a reduction in blur correction effect even in a panning state and a control method thereof.

1 is a block diagram showing a configuration example of a shake correction apparatus according to an embodiment of the present invention. (A) is a flowchart for explaining panning control processing performed by the panning control circuit 112 in the first embodiment, and (b) is panning control performed by the panning control circuit 112 according to the third embodiment of the present invention. The flowchart for demonstrating a process step different from 1st Embodiment among processes. The figure for demonstrating the process performed by S101 of Fig.2 (a). (A) blur correction data, (b) HPF 15 low-frequency cutoff frequency, and (c) blur remaining when panning operation is performed in an imaging apparatus equipped with the conventional blur correction apparatus shown in FIG. The figure which shows the time-dependent change of quantity. (A) Shake correction data and (b) Output of the offset change circuit 106 (OFFSET_NOW) when a panning operation similar to that shown in FIG. 4 is performed in the imaging apparatus equipped with the shake correction apparatus according to the first embodiment. (C) Remaining blur amount is a figure which shows a time-dependent change. (A) is a diagram showing the relationship between the panning start determination threshold IN_THRESH1 and the focal length of the zoom lens in the second embodiment, (b) is a diagram showing the relationship between the panning end determination threshold IN_THRESH2 and the focal length, and (c) is a diagram. The figure which shows the relationship between the panning end determination angular velocity threshold value OUT_THRESH2 and a focal distance in 4th Embodiment. FIG. 6D is a diagram showing temporal changes in (a) angular velocity data, (b) blur correction data, and (c) output of the offset change circuit 106 at the end of the panning operation of the shake correction apparatus according to the third embodiment. FIG. 6 is a diagram showing a change with time of a value obtained by removing a panning component that does not need to be corrected from a difference between an actual blur amount at the end of the panning operation and blur correction data that is an output of the focal length calculation circuit 17; The flowchart for demonstrating the panning control process which the panning control circuit 112 which concerns on 5th Embodiment performs. In the fifth embodiment, (a) a diagram showing a relationship between zoom speed and ZOOM_OFFSET_SPEED, (b) a diagram showing a relationship between focal length and FOCAL_OFFSET_GAIN, and (c) a diagram showing a relationship between blur correction data CORRECT_DATA and CORRECT_OFFSET_GAIN. (D) The figure which shows the relationship between a focal distance and the low-pass cutoff frequency of HPF15. (A) angular velocity data, (b) blur correction data, and (c) low-frequency cutoff frequency of HPF 15 when a panning operation is performed during high-speed zooming in an imaging device equipped with a conventional blur correction device. FIG. (A) angular velocity data, (b) blur correction data, and (c) offset change circuit 106 when an operation similar to that shown in FIG. 10 is performed in an imaging apparatus equipped with the blur correction apparatus of the fifth embodiment. Output, (d) The figure which shows the time-dependent change of the low frequency cut-off frequency of HPF15. (A) is a flowchart for explaining a panning control process performed by the panning control circuit 112 according to the sixth embodiment of the present invention, and (b) is a panning control circuit 112 according to the seventh embodiment of the present invention. The flowchart for demonstrating the process step different from 6th Embodiment among the panning control processes performed. It is the graph which showed the relationship between the output signal of the signal substitution circuit 107, and angular displacement data in the 6th Embodiment of this invention. (A)-(c) are the angular velocity data, the low-frequency cutoff frequency of the HPF 15, and the output of the integrator 16 when an abrupt panning operation is performed in an imaging device equipped with a conventional shake correction device. FIGS. 9D and 9E are diagrams showing changes over time in certain angular displacement data, and FIG. 9D shows signal replacement when a similar panning operation is performed in an imaging apparatus equipped with the shake correction apparatus in the sixth embodiment. The figure which shows the time-dependent change of the output signal of a circuit 107, and angular displacement data. The flowchart for demonstrating the panning control process which the panning control circuit 112 which concerns on the 8th Embodiment of this invention performs. (A) is a figure which shows the time-dependent change of the output (angular velocity data) of the A / D converter 14 when the panning operation is performed, and (b) is the angular velocity data when the three types of panning operations are performed. FIG. In the eighth embodiment, (a) a diagram showing the relationship between the time CANCEL_TIME since the start of the panning operation and OFFSET_CANCEL_ORIGINAL, (b) a diagram showing the relationship between PAN_TIME and PAN_TIME_GAIN, (c) GYRO_PEAK and GYRO_PEAK_GAIN FIG. (A), (b) is a figure which shows a time-dependent change of angular velocity data and the low-pass cutoff frequency of HPF15 when panning operation | movement is performed with the imaging device with which the conventional blurring correction apparatus was mounted, (c) ) Shows changes over time in the angular velocity data and the output of the offset change circuit 106 when a panning operation similar to that shown in FIG. 18A is performed in the imaging apparatus equipped with the shake correction apparatus in the eighth embodiment. FIG. The block diagram which shows the structural example of the conventional blurring correction apparatus.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a configuration example of a shake correction apparatus capable of implementing all of the embodiments of the present invention. The same reference numerals are assigned to the same configurations as those in FIG. However, it should be noted that not all of the functional blocks shown in FIG. 1 are essential in each embodiment. And it cannot be overemphasized that the imaging device which concerns on embodiment which has a non-essential functional block may be the structure which does not have a non-essential functional block. In the following embodiments, it is assumed that the shake correction apparatus is used for an imaging apparatus. A shake detection (blur detection) sensor that detects shake applied to the shake correction device and outputs shake information, in this embodiment, an angular velocity sensor 11 is attached to an imaging device main body (not shown) as an example, and the shake applied to the device is detected. It detects and the magnitude of the shake is detected as an angular velocity. The blur correction circuit 19 corrects the blur of the image due to the shake applied to the apparatus.

  The blur correction circuit 19 drives a correction lens of a correction optical system, which is a part of an imaging optical system (lens group) included in an imaging device (not shown), in a direction perpendicular to the optical axis in accordance with the blur correction data. It may be an optical blur correction circuit that performs blur correction of a captured image by decentering the axis. In addition, the blur correction circuit 19 may be an electronic blur correction circuit that performs blur correction by moving an area read from an image sensor included in the imaging device in accordance with blur correction data. Alternatively, the blur correction circuit 19 may be a sensor shift type blur correction circuit that moves the image sensor in a plane perpendicular to the optical axis in accordance with the blur correction data.

  In FIG. 1, an offset change circuit 106, a signal replacement circuit 107, an adder / subtractor 108, and a switch 109 are added as functional blocks realized by the microcomputer 120, and the operation of the panning control circuit 112 is changed. However, it differs from FIG.

  It goes without saying that at least one or more functional blocks realized by the microcomputer 120 executing a program stored in a non-volatile memory (not shown) may be realized by hardware.

  The offset changing circuit 106 generates a signal for returning the blur correction data to the correction center position according to the determination result of the panning control circuit 112, and outputs the signal to the adder / subtractor 108. Details of the operation of the offset changing circuit 106 will be described later. An adder / subtractor 108 serving as an offset application unit supplies the switch 109 with the result of applying the offset value output from the offset changing circuit 106 to the output signal of the high-pass filter (HPF) 15 that cuts off the low-frequency component. In the present embodiment, the adder / subtracter 108 applies the offset value by subtracting the offset value from the output signal of the HPF 15.

  The signal replacement circuit 107 serving as a signal generation unit outputs a predetermined signal to the switch 109 according to the determination result of the panning control circuit 112. Details of the operation of the signal replacement circuit 107 will be described later. The switch 109 selects one of the output of the adder / subtractor 108 and the output of the signal replacement circuit 107 according to the determination result of the panning control circuit 112 and supplies the selected signal to the integrator 16.

  The integrator 16 integrates the angular velocity data output from the HPF 15 and supplies the integration result as angular displacement data to the focal length calculation circuit. The DC cutoff frequency of the HPF 15 and the time constant used by the integrator 16 for integration calculation are variable under the control of the panning control circuit 112.

  The panning control circuit 112 outputs angular velocity data output from the A / D converter 14, angular displacement data output from the integrator 16, and blur correction data output from the focal length calculation circuit 17 functioning as blur correction data calculation means. Based on the above, it is determined whether or not the imaging device is in a panning state. That is, the panning control circuit 112 determines whether or not the movement of the imaging device is due to the user's panning operation. The panning control circuit 112 performs panning control when it is determined that the imaging apparatus is in the panning state. In panning control, the panning control circuit 112 controls operations of the HPF 15, the integrator 16, the offset changing circuit 106, the signal replacement circuit 107, and the switch 109.

● (first embodiment)
Hereinafter, the operation of the panning control circuit 112 according to the first embodiment of the present invention will be described. In this embodiment, the signal replacement circuit 107 and the switch 109 are not essential, and the output of the adder / subtractor 108 may be directly input to the integrator 16.

  FIG. 2A is a flowchart for explaining the panning control process performed by the panning control circuit 112 in the first embodiment. Note that the processing described below with reference to FIG. 2A is repeatedly performed every predetermined period, for example, every vertical synchronization period (1/60 second).

  In S101, the panning control circuit 112 calculates the value of the variable OFFSET_DATA for determining the output signal of the offset changing circuit 106. Note that the output signal of the offset change circuit 106 in the current panning control process is defined as OFFSET_NOW, and the output signal of the offset change circuit 106 in the process one time before (one vertical synchronization period before) is defined as OFFSET_PAST.

  A method of calculating OFFSET_DATA that is a variable for determining the output signal of the offset changing circuit 106 in S101 will be described with reference to FIG. In FIG. 3, the horizontal axis represents blur correction data (CORRECT_DATA) that is an output signal of the focal length calculation circuit 17, and the vertical axis represents the variable OFFSET_DATA. As described above, the panning control circuit 112 calculates the value of the variable OFFSET_DATA according to the value of CORRECT_DATA.

  The panning control circuit 112 determines that the imaging device is in the panning state when the absolute value of CORRECT_DATA exceeds the panning start determination threshold IN_THRESH1. The panning control circuit 112 determines that the imaging device is not in the panning state when the absolute value of CORRECT_DATA falls below the panning end determination threshold value OUT_THRESH1 (second threshold value). Here, the panning end determination threshold value OUT_THRESH1 is set to a value smaller than the panning start determination threshold value IN_THRESH1.

  As shown in FIG. 3, the panning control circuit 112 sets the value of OFFSET_DATA to zero when the absolute value of CORRECT_DATA is equal to or less than the panning start determination threshold IN_THRESH1 (first threshold). On the other hand, when the value of CORRECT_DATA is larger than the panning start determination threshold IN_THRESH1, the panning control circuit 112 calculates the value of OFFSET_DATA so that the value of OFFSET_DATA increases as the value of CORRECT_DATA increases. Further, when the value of CORRECT_DATA is smaller than the panning start determination threshold value -IN_THRESH1, the panning control circuit 112 calculates the value of OFFSET_DATA so that the value of OFFSET_DATA decreases as CORRECT_DATA decreases. As described above, the panning control circuit 112 increases the absolute value of OFFSET_DATA as the value of the blur correction data CORRECT_DATA approaches the limit of the operation range of the blur correction circuit 19 (hereinafter referred to as a correction end). Calculate the value of OFFSET_DATA.

  When the value of OFFSET_DATA is calculated in S101, the panning control circuit 112 determines in S102 whether OFFSET_PAST is zero, that is, whether the panning state has not been determined in the previous process. When OFFSET_PAST is zero and the panning state has not been determined in the previous process, the panning control circuit 112 shifts the process to S103. Note that the initial value of OFFSET_PAST is zero. Accordingly, in the first process, the panning control circuit 112 always performs the process of S103.

  In S103, the panning control circuit 112 determines whether or not the OFFSET_DATA calculated in S101 is less than zero. If the OFFSET_DATA is less than zero, the sign flag SIGN_FLAG is reset (S104), and if it is less than zero, the sign flag SIGN_FLAG is set. (S105). Since the processing of S103 to S105 is performed only when it is determined that it is not in the panning state in the previous processing, after it is determined that it is once in the panning state, the sign flag is determined until it is determined that it is not in the panning state. The state of SIGN_FLAG is retained. The panning control circuit 112 proceeds to the process of S111 after the process of S104 or S105.

  In S111, the panning control circuit 112 sets the value of OFFSET_DATA calculated in S101 to the output OFFSET_NOW of the offset change circuit 106. As described with reference to FIG. 3, when the absolute value of CORRECT_DATA exceeds the panning start determination threshold IN_THRESH1, the panning control circuit 112 determines that the imaging device is in the panning state. At this time, the panning control circuit 112 sets a value that brings the output CORRECT_DATA of the focal length calculation circuit 17 close to zero (correction center position) in the output OFFSET_NOW of the offset change circuit 106.

  In S102, if the OFFSET_PAST is not zero, that is, if it is determined that the panning state is obtained in the previous process, the panning control circuit 112 proceeds to the process in S106. In S106, the panning control circuit 112 determines whether or not the sign flag SIGN_FLAG is set, that is, determines the panning direction.

  If it is determined in S106 that SIGN_FLAG is set, the panning control circuit 112 determines whether or not the OFFSET_DATA calculated in S101 is smaller than the output OFFSET_PAST of the offset change circuit 106 of the previous process (S108). . If it is determined in S106 that SIGN_FLAG is not set, the panning control circuit 112 determines whether or not OFFSET_DATA calculated in S101 is larger than the output OFFSET_PAST of the offset change circuit 106 in the previous process. (S107).

  As described above, in the processes of S106 to S108, when it is determined that the panning control circuit 112 is in the panning state in the previous process, the blur correction data CORRECT_DATA is corrected by the blur correction circuit 19 in the current process. It is determined whether or not the edge is approaching.

  If it is determined in S107 that OFFSET_DATA is greater than OFFSET_PAST, or if it is determined in S108 that OFFSET_DATA is smaller than OFFSET_PAST, the panning control circuit 112 proceeds to the process of S111. In step S <b> 111, the panning control circuit 112 sets the value of OFFSET_DATA calculated in step S <b> 101 as the output of the offset change circuit 106. That is, when it is already determined that the camera is in the panning state, if the value of the blur correction data further approaches the correction end of the blur correction circuit 19, the panning control circuit 112 increases the blur correction data closer to zero. The output of the offset changing circuit 106 is controlled.

As described above, in the present embodiment, when the value of the blur correction data approaches the correction end of the blur correction circuit 19 in a state where the panning state is determined, an offset that reduces the output of the HPF 15 is given. As a result, the panning component included in the angular velocity data output by the HPF 15 can be removed without changing the low-frequency cutoff frequency of the HPF 15. Therefore, even if the panning state is determined, the blurring effect of the imaging device due to camera shake or body shake is not reduced.

  If it is determined in S107 that OFFSET_DATA is equal to or lower than OFFSET_PAST, or if it is determined in S108 that OFFSET_DATA is equal to or higher than OFFSET_PAST, the panning control circuit 112 proceeds to processing in S109. That is, when it is determined that the panning state has already been reached and the value of the blur correction data approaches zero, the panning control circuit 112 proceeds to the process of S109.

  In S109, the panning control circuit 112 determines whether or not the absolute value of the blur correction data CORRECT_DATA is smaller than the panning end determination threshold OUT_THRESH1. If it is determined in S109 that the absolute value of CORRECT_DATA is smaller than OUT_THRESH1, the panning control circuit 112 determines that the panning state has ended, and the process proceeds to S111. As shown in FIG. 3, when the absolute value of CORRECT_DATA is smaller than OUT_THRESH1, the panning control circuit 112 determines the value of OFFSET_DATA to be zero. Therefore, the value of OFFSET_NOW is set to zero by the processing of S111. .

  On the other hand, when it is determined in S109 that the absolute value of CORRECT_DATA is equal to or greater than OUT_THRESH1, the panning control circuit 112 sets the output OFFSET_PAST of the offset change circuit 106 of the previous process to the output OFFSET_NOW of the offset change circuit 106. (S110). As described above, the output OFFSET_NOW of the offset changing circuit 106 is not updated and is held at the value set in the previous process until it is determined in S109 that the panning state is not reached (panning is completed).

  After the processing of S110 or S111, the panning control circuit 112 updates OFFSET_PAST with the value of OFFSET_NOW (S112) for use in the processing of the next cycle (S112), ends one cycle of the panning control processing, and passes the next cycle after a predetermined time. Start processing.

  The effectiveness of panning control in this embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 shows the blur correction data (CORRECT_DATA), the low-frequency cutoff frequency of the HPF 15 and the remaining blur amount when the panning operation is performed in the imaging apparatus equipped with the conventional blur correction apparatus shown in FIG. It is a figure which shows a time-dependent change. FIG. 5 shows the blur correction data (CORRECT_DATA), the output of the offset change circuit 106 (OFFSET_NOW) when the panning operation similar to that in FIG. 4 is performed in the imaging apparatus equipped with the blur correction apparatus according to the present embodiment, It is a figure which shows a time-dependent change of the blurring remaining amount.

  FIG. 4A shows a change in blur correction data that is an output of the focal length calculation circuit 17 in FIG. 19 when the panning operation starts at time T1 and ends at time T4. The blur correction data has a waveform in which a low frequency panning component is superimposed on a high frequency camera shake waveform. FIG. 4B shows a change with time of the low-frequency cutoff frequency of the HPF 15 when the panning operation described above is performed. FIG. 4C shows a change over time in the difference (blur remaining amount) between the actual blur amount and the blur correction data when the panning operation described above is performed.

  FIG. 5A shows a change in blur correction data, which is an output of the focal length calculation circuit 17 in FIG. 1, when the panning operation starts at time T1 'and ends at time T4'. FIG. 5B shows a change with time of the output of the offset changing circuit 106 when the panning operation described above is performed. FIG. 5C shows the change over time in the difference (blur remaining amount) between the actual blur amount and the blur correction data when the above-described panning operation is performed.

  In the conventional panning control shown in FIG. 4, the panning control circuit 18 determines that the panning state is reached at time T2 when the magnitude of the blur correction data exceeds IN_THRESH1 in FIG. Then, as shown in FIG. 4B, the panning control circuit 18 increases the low frequency cutoff frequency of the HPF 15 from time T2. As a result, as shown in FIG. 4A, the blur correction data gradually approaches zero from time T3. Thereafter, at time T4 when the magnitude of the blur correction data is less than OUT_THRESH1 in FIG. 4A, the panning control circuit 18 determines that the panning state has ended. Then, as shown in FIG. 4B, the panning control circuit 18 returns the low frequency cutoff frequency of the HPF 15 to a low state at time T4.

  FIG. 4C shows the amount of remaining blur due to the above panning control. From time T2 to T4, it is the panning component that increases the blur remaining amount in one direction. When the panning state is determined, the panning component is removed from the blur correction data by increasing the low frequency cutoff frequency of the HPF 15. However, as described above, since the panning component and the blur component are close to each other in the frequency band, if the low frequency cutoff frequency of the HPF 15 is increased, the blur component to be corrected is also attenuated. As a result, as shown in FIG. 4C, the remaining blur amount ERROR_PAN_OLD excluding the panning component when panning is performed is compared with the remaining blur amount ERROR_NORMAL_OLD when panning is not performed. It gets bigger.

  On the other hand, according to the present embodiment, the panning control circuit 112 determines that the imaging apparatus is in the panning state at time T2 ′ when the magnitude of the blur correction data exceeds IN_THRESH1 in FIG. Then, as shown in FIG. 5B, the panning control circuit 112 increases the output of the offset changing circuit 106 from time T2 ′ (FIG. 2A, S111). From time T2 ′ to T3 ′, when the blur correction data in FIG. 5A increases, the output of the offset change circuit 106 also increases. After that, in FIG. 5A, the panning control circuit 112 holds the output of the offset changing circuit 106 until time T4 ′ when the size of the blur correction data is less than OUT_THRESH1 and it is determined that the panning state is finished. As a result, as shown in FIG. 5A, the blur correction data gradually approaches zero from time T3 ′. As a result, the correction lens or the image sensor moves toward the center of the optical axis in the case of optical blur correction, and the area to be read moves toward the center of the image sensor in the case of electronic blur correction. Then, as shown in FIG. 5B, the panning control circuit 112 returns the output of the offset changing circuit 106 to zero at time T4 ′.

  By the panning control in this embodiment, the amount of remaining blur becomes as shown in FIG. From time T2 'to T4', it is the panning component that increases the blur remaining amount, and the panning component is removed from the correction data by increasing the output of the offset changing circuit 106. The output of the offset changing circuit 106 is held at a constant value from time T3 ′ to T4 ′, and when the constant value is integrated by the integrator 16, it monotonously increases or decreases monotonously in one direction. As a result, it is possible to smoothly bring the shake correction data close to zero without attenuating the shake component to be corrected from the shake correction data. As a result, as shown in FIG. 5C, the remaining blur amount ERROR_PAN_NEW excluding the panning component when panning is performed even when compared with the remaining blur amount ERROR_NORMAL_NEW when panning is not performed. Does not change. That is, the blur correction effect is not reduced even during panning.

  As described above, according to the present embodiment, when the panning state is determined, instead of performing control to increase the low frequency cutoff frequency of the HPF 15, the output of the HPF 15 is reduced by the offset value. Remove panning ingredients. Thereby, the influence of the panning component on the blur correction data can be suppressed without reducing the blur correction effect.

● (Second Embodiment)
Next, a second embodiment of the present invention will be described. In the present embodiment, the panning start determination threshold IN_THRESH1 and the panning end determination threshold OUT_THRESH1 that were fixed values in the first embodiment according to the focal length (angle of view) of the zoom lens having a variable focal length in the imaging apparatus. The value of is changed.

  FIG. 6A shows the relationship between the panning start determination threshold IN_THRESH1 and the focal length of the zoom lens in the present embodiment. As shown in FIG. 6A, the panning control circuit 112 in this embodiment sets the panning start determination threshold value IN_THRESH1 to be smaller as the focal length of the zoom lens becomes larger (the angle of view becomes smaller).

  If the angular displacement data output from the integrator 16 is θ and the focal length data of the zoom lens is f, the blur correction data CORRECT_DATA output from the focal length calculation circuit 17 is CORRECT_DATA = ftanθ. That is, when blurring at the same angular velocity occurs in the blur correction device 100, the amount of change in blur correction data increases as the focal length of the lens increases. When panning is performed when the focal length of the lens is large, the blur correction data approaches the correction end faster than when the focal length is small. That is, the correction limit of the blur correction circuit 19 is easily reached. Therefore, in the present embodiment, as shown in FIG. 6A, the panning start determination threshold IN_THRESH1 is decreased as the focal length of the lens increases, and the panning state is determined at an earlier timing. Accordingly, it is possible to suppress a reduction in the blur correction effect during the panning operation at the time of telephoto shooting.

  On the other hand, FIG. 6B shows the relationship between the panning end determination threshold value OUT_THRESH1 and the focal length of the lens in the present embodiment. As shown in FIG. 6B, the panning control circuit 112 in the present embodiment sets the panning end determination threshold value OUT_THRESH1 to be larger as the focal length of the lens is larger (the angle of view is smaller).

  As described above, when the shake at the same angular velocity occurs in the shake correction apparatus 100, the amount of change in the shake correction data increases as the focal length of the lens increases. When the output of the offset changing circuit 106 is the same value, the speed at which the blur correction data approaches zero increases as the focal length of the lens increases. Therefore, if the panning end determination is delayed when the focal length of the lens is large, there is a risk that the blur correction data passes through zero and approaches the opposite correction end. Therefore, as the focal length of the lens increases, the value of the panning end determination threshold OUT_THRESH1 is increased as shown in FIG. 6B, and the panning end determination is performed at an earlier timing, whereby the blur correction data is obtained. Prevents heading to the opposite correction end.

  As described above, according to this embodiment, even when the focal length of the lens is changed, the same effect as that of the first embodiment can be realized.

● (Third embodiment)
Next, a third embodiment of the present invention will be described. In the present embodiment, in addition to the absolute value of the correction data being less than the panning end determination threshold OUT_THRESH1, it is determined that the panning state has ended when the absolute value of the angular velocity angular velocity data (GYRO_DATA) satisfies the condition. It is characterized by doing. In this embodiment, the signal replacement circuit 107 and the switch 109 are not essential, and the output of the adder / subtractor 108 may be directly input to the integrator 16.

  FIG. 2B is a flowchart for explaining operations different from those of the first embodiment in the panning control processing performed by the panning control circuit 112 in the third embodiment. The panning control process of this embodiment is the same as that of the first embodiment except that an angular velocity data determination process (S210) is added between S109 and S111. Therefore, only different processes will be described.

  In S109, the panning control circuit 112 determines whether or not the absolute value of the blur correction data CORRECT_DATA is smaller than the panning end determination threshold OUT_THRESH1. If it is determined in S109 that the absolute value of CORRECT_DATA is equal to or greater than OUT_THRESH1, the panning control circuit 112 sets the output OFFSET_PAST of the offset change circuit 106 of the previous process to the output OFFSET_NOW of the offset change circuit 106 ( S110).

  On the other hand, if it is determined in S109 that the absolute value of CORRECT_DATA is smaller than OUT_THRESH1, the panning control circuit 112 proceeds to S210. In S210, the panning control circuit 112 determines whether the absolute value of the angular velocity data (GYRO_DATA) that is the output of the A / D converter 14 is smaller than the panning end determination angular velocity threshold OUT_THRESH2. The panning end determination angular velocity threshold OUT_THRESH2 corresponds to a third threshold.

  In S210, when it is determined that the absolute value of GYRO_DATA is smaller than the panning end determination angular velocity threshold OUT_THRESH2, the panning control circuit 112 determines that the panning state has ended, and the process proceeds to S111.

Next, the technical meaning of the process of S210 will be described in detail with reference to FIG.
7 shows (a) angular velocity data (GYRO_DATA), (b) blur correction data (CORRECT_DATA), and (c) output of the offset changing circuit 106 (OFFSET_NOW) at the end of the panning operation (near time T4 ′ in FIG. 5). The change with time is shown. FIG. 7D shows a panning component that does not need to be corrected from the difference (blur remaining amount) between the actual blur amount at the end of the panning operation and the blur correction data that is output from the focal length calculation circuit 17. The change over time of the removed value is shown.

  As in the first embodiment, when it is determined that the panning state has ended when the absolute value of the blur correction data is below OUT_THRESH1, it is determined that panning has ended at the timing of time T11 in FIG. Then, the output of the offset changing circuit 106 is returned to zero (S111).

  At this time, as shown in FIG. 7A, the following phenomenon occurs when the absolute value of the angular velocity data is large (OUT_SHRESH2 or more), that is, the blur speed is high. At the timing of time T11 when the blur speed is large, the remaining blur amount is large as shown in FIG. 7D due to the influence of the detection error of the angular velocity sensor 11 and other calculation errors. As described above, if the output of the offset changing circuit 106 is returned to zero at the timing when the amount of remaining blur becomes large, the amount of remaining blur becomes larger due to the influence of the output change of the offset changing circuit 106.

  Therefore, in the present embodiment, when the absolute value of the blur correction data is less than OUT_THRESH1 and the absolute value of the angular velocity data is less than the panning end determination angular velocity threshold OUT_THRESH2, it is determined that the panning state is finished.

  The absolute value of the angular velocity data shown in FIG. 7A falls below the panning end determination angular velocity threshold OUT_THRESH2 at the timing of time T12. At the timing of time T12, the absolute value of the angular velocity data in FIG. 7A is small, that is, the blur speed is low. At the timing of time T12 when the blur speed is low, the remaining blur amount is also small as shown in FIG. By returning the offset value OFFSET_NOW to zero when the remaining blur amount is reduced (S111), the effect of changing the offset value on the remaining blur amount can be sufficiently suppressed compared to when returning the remaining blur amount timing. is there.

  As described above, according to the present embodiment, not only the absolute value of the shake correction data is small but also the removal of the panning component is terminated in a state where the angular velocity data is small. The influence exerted can be sufficiently suppressed.

● (Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In the present embodiment, the value of the panning end determination angular velocity threshold OUT_THRESH2, which is a fixed value in the third embodiment, is changed according to the focal length (view angle) of the zoom lens having a variable focal length. It is characterized by that.

  FIG. 6C shows the relationship between the panning end determination angular velocity threshold OUT_THRESH2 and the focal length of the lens in this embodiment. As shown in FIG. 6C, the panning control circuit 112 according to the present embodiment sets the panning end determination angular velocity threshold OUT_THRESH2 to be larger as the focal length of the lens is larger (the angle of view is smaller).

  As described above, when the shake at the same angular velocity occurs in the shake correction apparatus 100, the amount of change in the shake correction data increases as the focal length of the lens increases. When the output of the offset changing circuit 106 is the same value, the speed at which the blur correction data approaches zero increases as the focal length of the lens increases. Therefore, if the panning end determination is delayed when the focal length of the lens is large, there is a risk that the blur correction data passes through zero and approaches the opposite correction end. Accordingly, as the focal length of the lens increases, as shown in FIG. 6C, the panning end determination angular velocity threshold OUT_THRESH2 is increased, panning end determination is performed at an earlier timing, and the blur correction data is reversed. It is prevented from going to the correction end.

  As described above, according to this embodiment, even when the focal length of the lens is changed, the same effect as that of the third embodiment can be realized.

● (Fifth Embodiment)
Next, a fifth embodiment of the present invention will be described. The present embodiment relates to a panning control method when zooming is performed. In the present embodiment, the signal replacement circuit 107 and the switch 109 in FIG. 1 are not essential.

  FIG. 8 is a flowchart for explaining the panning control process performed by the panning control circuit 112 according to this embodiment. Note that the processing described below with reference to FIG. 8 is repeatedly performed every predetermined period, for example, every vertical synchronization period (1/60 second).

  In S301, the panning control circuit 112 acquires the focal length of the lens through the focal length calculation circuit 17, and determines whether or not it is increased (change from the wide angle side to the telephoto side) compared to the focal length acquired in the previous process. To do. When it is determined in S301 that there is no increase in the focal length, the panning control circuit 112 proceeds to the process of S302.

  If the output signal of the offset changing circuit 106 when the zooming operation is performed is defined as OFFSET_ZOOM, the panning control circuit 112 sets the value of OFFSET_ZOOM to zero in S302 and ends the process. Here, when this embodiment is used in combination with one or more of the first to fourth embodiments, the output of the offset change circuit 106 is a value obtained by adding OFFSET_NOW and OFFSET_ZOOM. When this embodiment is implemented alone, the output of the offset change circuit 106 is OFFSET_ZOOM.

  If it is determined in S301 that there is an increase in focal length, the panning control circuit 112 proceeds to the process of S303. In S303, the panning control circuit 112 calculates the value of OFFSET_ZOOM as shown in FIG.

In the present embodiment, the panning control circuit 112 determines the value of OFFSET_ZOOM according to the zoom speed (increased speed of focal distance), the focal distance, and the values of blur correction data. The parameter determined according to the zoom speed is ZOOM_OFFSET_SPEED, the parameter determined according to the focal length is FOCAL_OFFSET_GAIN, and the parameter determined according to the blur correction data is CORRECT_OFFSET_GAIN. At this time, the panning control circuit 112 calculates the value of OFFSET_ZOOM by the following (Equation 1).
OFFSET_ZOOM = ZOOM_OFFSET_SPEED × FOCAL_OFFSET_GAIN × CORRECT_OFFSET_GAIN… (Formula 1)

  FIG. 9A shows the relationship between the zoom speed and ZOOM_OFFSET_SPEED. The value of ZOOM_OFFSET_SPEED is set to zero when the zoom speed is equal to or less than the zoom speed threshold SPEED_THRESH that is the fourth threshold. When the zoom speed is higher than SPEED_THRESH, the value of ZOOM_OFFSET_SPEED is increased as the zoom speed increases. This is because as the speed at which the focal length increases, the speed at which the blur correction data approaches the correction end increases, and thus the speed at which the blur correction data approaches zero must be increased.

  FIG. 9B is a diagram showing the relationship between the focal length and FOCAL_OFFSET_GAIN. FOCAL_OFFSET_GAIN is a coefficient by which ZOOM_OFFSET_SPEED is multiplied, and the smaller the focal length, the smaller the value. When the output of the offset changing circuit 106 is the same value, the speed at which the blur correction data approaches zero increases as the focal length increases. For this reason, the speed at which the blur correction data approaches zero during zooming increases, resulting in an unnatural movement. As shown in FIG. 9B, if the output of the offset changing circuit 106 is reduced as the focal length increases, the speed at which the blur correction data approaches zero can be made constant even during zooming, resulting in an unnatural movement. Can be prevented.

  FIG. 9C is a diagram illustrating a relationship between the blur correction data CORRECT_DATA and CORRECT_OFFSET_GAIN. CORRECT_OFFSET_GAIN is a coefficient to be multiplied by ZOOM_OFFSET_SPEED as in FOCAL_OFFSET_GAIN, and the larger the value of the blur correction data, the larger the value. This is because when the blur correction data is close to the correction end, it is necessary to make the blur correction data approach zero quickly in order to prevent reaching the correction end. When blur correction data is zero, the value of CORRECT_OFFSET_GAIN is also zero.

  Therefore, the value of OFFSET_ZOOM is zero when the zoom speed is equal to or less than the zoom speed threshold SPEED_THRESH. Further, when the zoom speed is larger than the zoom speed threshold value, the value of OFFSET_ZOOM becomes a larger value as the zoom speed is faster, the focal length is smaller, and the value of the blur correction data is larger. The value of OFFSET_ZOOM is given from the panning control circuit 112 to the offset changing circuit 106.

  The panning control circuit 112 calculates OFFSET_ZOOM in S303, and then proceeds to S304. In step S304, the panning control circuit 112 determines whether or not the current focal length acquired in step S301 is greater than the focal length threshold ZOOM_THRESH. If the focal length is greater than ZOOM_THRESH, the process proceeds to step S305.

  In step S <b> 305, the panning control circuit 112 sets the low frequency cutoff frequency of the HPF 15. In S305, the panning control circuit 112 calculates the low-frequency cutoff frequency of the HPF 15 as shown in FIG.

  That is, in the present embodiment, the panning control circuit 112 calculates the low-frequency cutoff frequency of the HPF 15 so that the focal length increases as the focal length increases when the focal length exceeds the fifth threshold value ZOOM_THRESH.

  On the other hand, when the focal length is equal to or smaller than ZOOM_THRESH in S304, the panning control circuit 112 ends the process and waits for the next process start cycle.

  Next, the effectiveness of the panning control when the zooming operation in the present embodiment is performed will be described with reference to FIGS. 10 and 11. FIG. 10 shows temporal changes in angular velocity data, blur correction data, and low-frequency cut-off frequency of the HPF 15 when a panning operation is performed during high-speed zooming in an imaging device equipped with a conventional blur correction device. FIG.

  FIG. 11 shows the angular velocity data, the shake correction data, the output of the offset change circuit 106 (OFFSET_ZOOM), and the HPF 15 when the same operation as that in FIG. 10 is performed in the image pickup apparatus equipped with the shake correction device of this embodiment. It is a figure which shows the time-dependent change of a low-pass cutoff frequency.

  FIG. 10A shows a change in angular velocity data that is an output of the A / D converter 14 of FIG. FIG. 10A shows a change in angular velocity data with time when the zooming operation (zoom-in operation) and the panning operation are performed simultaneously from time T21, the zooming operation ends at time T22, and the panning operation ends at time T23. ing. FIG. 10B shows a change in blur correction data that is an output of the focal length calculation circuit 17 of FIG. The solid line indicates the blur correction data when the conventional panning control is performed, and the dotted line indicates the blur correction data when the conventional panning control is not performed. FIG. 10C shows a change with time of the low frequency cutoff frequency of the HPF 15 when conventional panning control is performed.

  FIG. 11A shows the change over time of GYRO_DATA (angular velocity data) that is the output of the A / D converter 14 in FIG. 1 when the same zooming operation and panning operation as in FIG. 10A are performed. ing. However, in FIG. 11, it is assumed that the zooming operation (zoom-in operation) and the panning operation are simultaneously performed from time T31, the zooming operation is completed at time T33, and the panning operation is completed at time T34.

FIG. 11B shows a change with time of the blur correction data which is the output of the focal length calculation circuit 17 of FIG. A solid line in FIG. 11B indicates blur correction data when the panning control of the present embodiment is performed, and a dotted line indicates blur correction data when the panning control of the present embodiment is not performed. FIG. 11C shows the change with time of the output of the offset changing circuit 106 when the above-described zooming operation and panning operation are performed. FIG. 11D shows the change with time of the low-frequency cutoff frequency of the HPF 15 according to the panning control of the present embodiment.
The blur correction data for correcting blur at the same angular velocity increases in proportion to the focal length. Therefore, as shown in FIGS. 10A and 11A, when the panning operation and the high-speed zooming (zoom-in) operation are performed at the same time, the closer to the TELE side, the closer to FIGS. 10B and 11B. As indicated by the dotted line, the blur correction data increases rapidly.

  In order to prevent the blur correction data from rapidly approaching the correction end of the blur correction circuit 19, the following control is performed in the conventional panning control. That is, as shown in FIG. 10C, during the high-speed zooming operation, the low frequency cutoff frequency of the HPF 15 is increased as the focal length increases during the time T21 to T22. As a result, as shown by the solid line in FIG. 10B, a sudden increase in the blur correction data is prevented.

  However, the conventional panning control has the following problems. After the zooming operation is completed at time T22, when the low frequency cutoff frequency of the HPF 15 is suddenly returned to the original value, the blur correction data changes rapidly, and the error amount of the blur correction data increases rapidly. Therefore, it is necessary to slowly lower the low frequency cutoff frequency from time T22 to T24. However, when the low frequency cutoff frequency of the HPF 15 is high, the blur component to be corrected is also attenuated by the HPF 15. In other words, after the zooming operation is completed, until the low-frequency cutoff frequency returns to the original value (between T22 and T24), the blur component attenuation does not return to the original value, and the blur remaining amount increases. End up.

  On the other hand, in the panning control according to the present embodiment, as shown in FIG. 11C, the offset changing circuit 106 according to OFFSET_ZOOM calculated by the calculation formula (Formula 1) from time T31 to T33 when the zooming operation is performed. Determine the output of. Furthermore, as will be described below, the cutoff frequency of the HPF 15 is not performed during the period until the focal length reaches ZOOM_THRESH, thereby minimizing the period during which the blur component is attenuated.

  Assume that the focal length becomes ZOOM_THRESH at time T32 in FIG. 11 during the zooming operation. In this case, the panning control circuit 112 increases the low-frequency cutoff frequency of the HPF 15 from time T32 to time T33 when the zooming operation ends, as shown in FIG. 11D, according to FIG. Then, after the zooming operation is completed, as shown in FIG. 11 (d), the low frequency cutoff frequency of the HPF 15 is gradually returned to a small value (value before change) over time T34. After time T34, the low frequency cutoff frequency of the HPF 15 returns to the original value. Therefore, in the conventional panning control, the state where the attenuation of the blur component is large continues for a long time from T21 to T24. However, in this embodiment, the time when the blur component is attenuated is a short time from T32 to T34, and The attenuation of the blur component is small. Therefore, the absolute amount of the remaining blur amount is small and the original state can be restored in a short time.

  Here, the reason why the control for increasing the low frequency cutoff frequency of the HPF 15 is performed will be described. As shown in FIG. 11C, from time T31 to time T33 when the zooming operation is performed, the output of the offset changing circuit 106 is increased so as to increase the speed at which the blur correction data approaches zero. ing. However, even after the zooming operation at time T33, when the panning is not completed as shown in FIG. 11A, the output of the offset changing circuit 106 is zero. For this reason, a phenomenon occurs in which the blur correction data suddenly approaches the correction end due to the panning component after completion of the zooming operation, particularly when the focal length is large. In the present embodiment, as shown in FIG. 11D, when the focal length is increased during the zooming operation, the low frequency cutoff frequency of the HPF 15 is increased. Thereby, the panning component immediately after the end of the zooming operation can be removed, and the phenomenon that the blur correction data suddenly approaches the correction end can be prevented.

  If the panning operation continues even after time T34, the low frequency cut-off frequency of the HPF 15 is returned from time T33 to T34 and shown in the flowcharts of FIGS. 2 (a) and 2 (b). Can be performed. As a result, it is possible to prevent a phenomenon in which the blur correction data suddenly approaches the correction end even after time T34 when the low-frequency cutoff frequency becomes small.

  As described above, in the present embodiment, in the panning control during the zooming operation, the output change control of the offset change circuit 106 and the low frequency cut-off frequency change control of the HPF 15 are used in combination. As a result, it is possible to minimize the time during which the low frequency cut-off frequency is increased, that is, the time during which the remaining blur amount is increased.

  As described above, according to the panning control method of the present embodiment, when the zoom operation is performed during panning, the offset value for reducing the output of the HPF 15 is increased when the zoom speed is equal to or higher than the threshold value. To do. Therefore, in addition to the effects of the above-described embodiment, even if a high-speed zoom operation is performed during panning, an increase in the amount of remaining blur can be prevented. Furthermore, the control for increasing the cutoff frequency of the HPF 15 from the time when the focal length of the lens exceeds a predetermined value is also used. Therefore, the time required to restore the cutoff frequency of the HPF 15 at the end of zooming is short, and the panning component is appropriately removed while minimizing the increase in the amount of blurring remaining due to the increase in the cutoff frequency of the HPF 15. can do.

● (Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. The present embodiment relates to a panning control method during rapid panning.
FIG. 12A is a flowchart for explaining the panning control process performed by the panning control circuit 112 in the present embodiment. Note that the processing described below with reference to FIG. 12A is repeatedly performed at predetermined intervals, for example, every 1/60 second.

  In S401, the panning control circuit 112 determines whether a flag CHANGE_FLAG that is set in S408 and reset in S412 is set. When CHANGE_FLAG is reset, the panning control circuit 112 proceeds to the process of S402.

  Here, the angular displacement data, which is the output signal of the integrator 16, is INT_DATA, and the change width when INT_DATA is monotonously increasing or monotonically decreasing is INT_INCREASE_WIDTH. In S402, the panning control circuit 112 determines whether the magnitude of INT_INCREASE_WIDTH is larger than the panning start determination integrator threshold IN_THRESH2 (sixth threshold). If the value of INT_INCREASE_WIDTH is larger than IN_THRESH2, the panning control circuit 112 proceeds to the process of S403.

  In S403, the panning control circuit 112 determines whether or not the absolute value of the angular velocity data GYRO_DATA that is the output of the A / D converter 14 is greater than the panning start determination angular velocity threshold IN_THRESH3 (seventh threshold). If the panning control circuit 112 determines that the absolute value of GYRO_DATA is greater than IN_THRESH3, the panning control circuit 112 determines that the imaging device is in the panning state, and proceeds to S404. On the other hand, when it is determined in S402 that the magnitude of INT_INCREASE_WIDTH is equal to or smaller than IN_THRESH2, the panning control circuit 112 determines that the imaging device is not in the panning state. In S403, when it is determined that the absolute value of GYRO_DATA is equal to or less than IN_THRESH3, the panning control circuit 112 determines that the imaging device is not in the panning state. When it is determined that the imaging apparatus is not in the panning state, the panning control circuit 112 ends the process and waits until the next process starts. Note that the determination order of S402 and S403 may be reversed.

  In S404, the panning control circuit 112 determines whether or not the angular velocity data GYRO_DATA that is the output of the A / D converter 14 is less than zero. If it is greater than or equal to zero, the panning control circuit 112 proceeds to the process of S406 and resets the sign flag SIGN_FLAG2. On the other hand, if it is less than zero, the panning control circuit 112 proceeds to the processing of S406 and sets the sign flag SIGN_FLAG2. After performing the processes of S405 and S406, the panning control circuit 112 proceeds to the process of S407.

  In S407, the panning control circuit 112 calculates the value of the replacement signal data GYRO_DUMMY output from the signal replacement circuit 107 of FIG. 1 according to the angular displacement data INT_DATA that is the output signal of the integrator 16, as shown in FIG. Specifically, when the absolute value of INT_DATA is equal to or less than INT_THRESH (less than the eighth threshold value), the value of GYRO_DUMMY is set to zero. Further, when the value of INT_DATA is larger than the threshold value INT_THRESH, the value is calculated so that the value of GYRO_DUMMY becomes a negative value as the value of INT_DATA increases. Furthermore, when the value of INT_DATA is smaller than the threshold value −INT_THRESH, the value is calculated so that the value of GYRO_DUMMY increases with a positive value as the value of INT_DATA decreases.

  After calculating GYRO_DUMMY in S407, the panning control circuit 112 proceeds to the process of S408. In S408, the panning control circuit 112 switches the state of the switch 109 from the state in which the output of the HPF 15 is connected to the integrator 16 to the state in which the output of the signal replacement circuit 107 is connected to the integrator 16, and sets the flag CHANGE_FLAG. To do. When the panning control circuit 112 switches the switch 109 in S408, the output GYRO_DUMMY of the signal replacement circuit 107 calculated in S407 is input to the integrator 16. As shown in FIG. 13, GYRO_DUMMY is larger as the absolute value of INT_DATA, which is the output of integrator 16, is larger, and has a sign opposite to that of INT_DATA. Therefore, INT_DATA, which is the output of integrator 16, tends to approach zero. Change.

  When the process of S408 ends, the panning control circuit 112 ends the process and waits until the timing for starting the next process.

  On the other hand, if CHANGE_FLAG is set in S401, that is, if the switch 109 is switched to give the output of the signal replacement circuit 107 to the integrator 16, the panning control circuit 112 proceeds to the processing of S409. In step S409, the panning control circuit 112 determines whether or not SIGN_FLAG2 is set, that is, determines whether the angular velocity data at the time of starting panning is negative or positive (zero or more).

  In S409, if SIGN_FLAG2 is reset, that is, if the angular velocity data at the time of panning start determination is positive, the panning control circuit 112 proceeds to the process of S410. In S410, the panning control circuit 112 determines whether GYRO_DATA is smaller than the panning end determination angular velocity threshold OUT_THRESH3. Note that OUT_THRESH3 is a value smaller than the panning start determination angular velocity threshold IN_THRESH3.

  In S409, if SIGN_FLAG2 is set, that is, if the angular velocity data at the time of starting panning is negative, the panning control circuit 112 proceeds to the processing of S411. In S411, the panning control circuit 112 determines whether GYRO_DATA is greater than -OUT_THRESH3.

  If it is determined in S410 that GYRO_DATA is smaller than OUT_THRESH3, or if it is determined in S411 that GYRO_DATA is greater than -OUT_THRESH3, the panning control circuit 112 determines that the panning state has ended, and the process proceeds to S412. In S412, the panning control circuit 112 switches the state of the switch 109 from a state in which the output of the signal replacement circuit 107 is connected to the integrator 16 to a state in which the output of the HPF 15 is connected to the integrator 16, and resets the flag CHANGE_FLAG. After the process of S412 is completed, the panning control circuit 112 ends the process and waits for the next process execution cycle.

  If it is determined in S410 that GYRO_DATA is greater than or equal to OUT_THRESH3, or if it is determined in S411 that GYRO_DATA is less than or equal to −OUT_THRESH3, the panning control circuit 112 determines that the panning state is continuing, and in S413. Transition to processing.

  In S413, the panning control circuit 112 determines whether or not the absolute value of the angular displacement data (INT_DATA) that is the output signal of the integrator 16 is smaller than the threshold value OUT_THRESH4. If it is determined in S413 that the absolute value of INT_DATA is smaller than the threshold value OUT_THRESH4, the panning control circuit 112 proceeds to the process of S414. Note that OUT_THRESH4 is a value smaller than INT_THRESH as shown in FIG.

  In S414, the panning control circuit 112 determines that the angular displacement data INT_DATA has sufficiently approached zero, and sets the value of GYRO_DUMMY to zero. This prevents the angular displacement data from passing through the center and moving toward the opposite correction end.

  If it is determined in S413 that the absolute value of INT_DATA is greater than or equal to the threshold value OUT_THRESH4, the panning control circuit 112 ends the process and waits for the next process execution cycle.

  Thus, in this embodiment, when the change amount of the monotonic increase or monotonic decrease of the angular displacement data output from the integrator 16 exceeds the threshold value and the absolute value of the angular velocity data exceeds the threshold value, the output of the HPF 15 is used instead. A value for reducing the angular displacement data is given to the integrator 16. This makes it difficult for the correction data to reach the correction end even when rapid panning is performed.

Next, the effectiveness of panning control in this embodiment will be described with reference to FIG.
FIGS. 14A to 14C show angular velocity data GYRO_DATA, HPF 15 low-frequency cut-off frequency, and angular displacement data when an abrupt panning operation is performed in an imaging apparatus equipped with a conventional shake correction apparatus. Indicates the change with time of INT_DATA. 14D and 14E show the output signal (GYRO_DUMMY) of the signal replacement circuit 107 when a similar panning operation is performed in the imaging apparatus equipped with the shake correction apparatus in the present embodiment. It is a figure which shows a time-dependent change of angular displacement data.

  FIG. 14A shows a change with time of angular velocity data which is an output of the A / D converter 14 of FIG. 19 or FIG. Here, it is assumed that a rapid panning operation is performed from time 0 and the panning operation is completed at time T53. FIG. 14B shows a change with time of the low-frequency cutoff frequency of the HPF 15 when a rapid panning operation is performed. FIG. 14C shows the change over time of the angular displacement data, which is the output of the integrator 16 of FIG. 19, the solid line shows the angular displacement data when the conventional panning control is performed, and the dotted line does not perform the panning control. The angular displacement data is shown.

  FIG. 14D is a diagram showing a change with time of replacement signal data, which is an output of the signal replacement circuit 107, when a rapid panning operation is performed. FIG. 14 (e) is a diagram showing the change with time of the angular displacement data, which is the output of the integrator 16 of FIG. In FIG. 14 (e), the solid line shows the change with time when the panning control of this embodiment is performed, and the dotted line shows the change with time when the panning control of this embodiment is not performed.

  As shown in FIG. 14A, when a panning operation is performed such that the angular velocity data increases in a short time, if the panning control is not performed, as shown in FIG. 14C and FIG. Then, the value of the angular displacement data rises rapidly and approaches the correction end (correction limit) of the shake correction circuit 19.

  In order to prevent the phenomenon in which the angular displacement data rapidly approaches the correction end, in the conventional panning control, as shown in FIG. Control was performed to increase the low-frequency cutoff frequency. As a result, as shown by the solid line in FIG. 14C, the phenomenon that the angular displacement data rapidly rises and approaches the correction end is prevented.

  However, the conventional panning control has the following problems. At time T53, the angular velocity data becomes smaller than the panning end determination angular velocity threshold OUT_THRESH3, and it is determined that the panning operation has ended. Thereafter, when the low-frequency cutoff frequency of the HPF 15 is suddenly restored to the original value, the blur correction data changes abruptly, and the error amount of the blur correction data increases rapidly. Therefore, it is necessary to slowly lower the low frequency cutoff frequency from time T53 to time T54. However, in a state where the low frequency cutoff frequency of the HPF 15 is high, the blur component to be corrected is also attenuated. That is, after the abrupt panning operation is finished, until the low-frequency cutoff frequency returns to the original value (between T53 and T54), the blur component attenuation does not return to the original value and the blur remaining amount increases. End up.

  On the other hand, as shown in S402 and S403 of FIG. 12A, the panning control circuit 112 according to the present embodiment starts the panning operation only when the angular velocity data becomes larger than the panning start determination angular velocity threshold IN_THRESH3 at time T51. Do not judge. Further, the panning control circuit 112 determines that the panning operation is started at time T52 when the angular displacement data monotonously increases or decreases and the change amount exceeds the panning start determination integrator threshold IN_THRESH2.

  When it is determined that the panning operation is started at time T52, the panning control circuit 112 determines the output GYRO_DUMMY of the signal replacement circuit 107 as shown in FIG. 13 (FIG. 14 (d)). Then, the panning control circuit 112 switches the state of the switch 109 and starts supplying the output of the signal replacement circuit 107 to the integrator 16 instead of the output of the HPF 15. When it is determined that the panning operation has been completed at time T53, the panning control circuit 112 returns the switch 109 so that the output of the HPF 15 is supplied to the integrator 16.

  From time T52 to T53, while the switch 109 is switched to a state in which the replacement signal data output from the signal replacement circuit 107 is supplied to the integrator 16, the angular displacement data output from the integrator 16 is shown in FIG. As shown, it approaches zero. As shown in FIG. 13, the panning control circuit 112 calculates replacement signal data GYRO_DUMMY whose sign is opposite to that of the displacement data and whose absolute value increases as the absolute value of the angular displacement data increases. Thus, when the angular displacement data is close to the correction end, a large value is reduced from the angular displacement data, and the blur correction data can be brought closer to zero faster.

  In addition, from time T52 to T53, the angular velocity data is switched to the output of the signal replacement circuit 107, and thus blur correction cannot be performed. Since the panning operation is an operation performed intentionally by the user, a natural image is obtained on the contrary when the correction is not performed. However, if the panning control is entered carelessly, the state where the blur correction is performed and the state where the blur correction is not performed are repeated, resulting in an unsightly image. Therefore, the panning control is prevented from being inadvertently performed by performing the panning start determination of the two conditions of S402 and S403 in the flowchart of FIG.

  As a result of performing the panning control of this embodiment, the angular displacement data becomes as shown by the solid line in FIG. 14E, and the phenomenon in which the angular displacement data rapidly approaches the correction end can be prevented. In addition, in the conventional panning control, the phenomenon that the blur remaining amount increases due to the low frequency cutoff frequency change control of the HPF 15 from time T53 to T54 in FIG. 14B is prevented, and the panning operation ends. It can be controlled to minimize the remaining blur amount immediately afterward.

  As described above, according to the present embodiment, when the panning operation is rapid, the replacement signal data is supplied to the integrator instead of the angular velocity data, so that the angular displacement data output from the integrator is at the correction end. Can be prevented. Then, when the panning operation is completed, it is possible to immediately start blur correction that can realize a sufficient effect. For this reason, it is possible to avoid the phenomenon that the blur remaining amount increases for a while after the end of panning, which occurs in the conventional panning control in which the low frequency cutoff frequency of the HPF 15 is increased during the panning operation.

  In this embodiment, the panning determination is performed based on the angular displacement data that is the output of the integrator 16, but the present invention is not limited to this. For example, the determination may be made using blur correction data output from the focal length calculation circuit 17, or an integrator dedicated to panning determination may be provided and the output may be used for the determination.

● (Seventh embodiment)
Next, a seventh embodiment of the present invention will be described. As in the sixth embodiment, this embodiment also relates to a panning control method at the time of rapid panning. The panning control process of this embodiment is characterized in that the process of S502 shown in FIG. 12B is performed instead of the process of S402 of the sixth embodiment shown in FIG. Since the other processing steps are the same as those in the sixth embodiment, only the processing of S502 that is characteristic of this embodiment will be described below, and description of the other processing will be omitted.

  In S402 of FIG. 12A, when the absolute value of the angular velocity data exceeds the threshold value IN_THRESH3 and the change width when the angular displacement data output from the integrator 16 monotonously increases or decreases exceeds the threshold value IN_THRESH2, panning is performed. It is determined that the operation has started. However, with this method, when the angular displacement data changes momentarily and then increases, the angular displacement data reaches the correction end before the monotonically increasing (decreasing) change width of the angular displacement data exceeds IN_THRESH2. There was a possibility.

  In the present embodiment, as shown in S502 of FIG. 12B, it is determined whether or not the absolute value of the angular displacement data that is the output signal of the integrator 16 is greater than the panning start determination angular displacement threshold IN_THRESH4. did. As shown in FIG. 13, the ninth threshold value IN_THRESH4 is set to a value closer to the correction end than OUT_THRESH4 and INT_THRESH. That is, when the absolute value of the angular velocity data exceeds the seventh threshold value IN_THRESH3 and the absolute value of the angular displacement data that is the output signal of the integrator 16 exceeds the ninth threshold value IN_THRESH4, the panning control circuit 112 of the present embodiment. It is determined that the panning operation has started. Accordingly, it is possible to perform panning start determination before the angular displacement data reaches the correction end, and it is possible to prevent the angular displacement data from reaching the correction end.

  As described above, according to this embodiment, even when the change direction of the angular displacement data due to the panning operation is not constant, the same effect as that of the sixth embodiment can be realized.

● (Eighth embodiment)
Next, an eighth embodiment of the present invention will be described. The present embodiment relates to a panning control method that takes into account the swinging back of the panning operation.

  FIG. 15 is a flowchart for explaining a panning control process performed by the panning control circuit 112 according to this embodiment. Note that the processing described below with reference to FIG. 15 is repeatedly performed at predetermined intervals, for example, every 1/60 second.

  FIG. 16A is a diagram showing a change with time in the output (angular velocity data) of the A / D converter 14 when the panning operation is performed. In FIG. 16A, during the panning operation period, the low frequency component of panning is attenuated by the DC cut filter 12, and the angular velocity data gradually decreases. When the panning operation ends, the angular velocity data swings in the direction opposite to the panning direction due to the influence of the low frequency component of panning attenuated by the DC cut filter 12. Thereafter, the angular velocity data converges to zero over time corresponding to the time constant of the DC cut filter 12. The process of the flowchart shown in FIG. 15 is a process for preventing a swing-back phenomenon in which a captured image moves due to a phenomenon in which angular velocity data fluctuates in the reverse direction after panning. During panning, the processing shown in the flowcharts of FIGS. 2A, 2B, 12A, and 12B may be performed, and the description thereof is omitted in this embodiment.

  In S601 of FIG. 15, the panning control circuit 112 determines whether or not a flag PAN_START_FLAG indicating that panning has started is set. If it is determined that PAN_START_FLAG is not set, the panning control circuit 112 proceeds to the process of S602.

  In S602, the panning control circuit 112 determines whether or not the angular velocity data (GYRO_DATA) that is the output of the A / D converter 14 is greater than the panning start determination angular velocity threshold IN_THRESH5.

  If it is determined in S602 that GYRO_DATA is greater than IN_THRESH5, the panning control circuit 112 determines that the panning operation of the imaging apparatus has started, and proceeds to the processing of S604 and S606. In step S604, the panning control circuit 112 resets SIGN_FLAG3 and stores the sign (positive) of angular velocity data at the start of panning. In S606, the panning control circuit 112 sets a flag PAN_START_FLAG indicating that panning has started.

  If it is determined in S602 that GYRO_DATA is equal to or less than IN_THRESH5, the panning control circuit 112 proceeds to the process of S603. In S603, the panning control circuit 112 determines whether or not the angular velocity data (GYRO_DATA) that is the output of the A / D converter 14 is smaller than the panning start determination angular velocity threshold −IN_THRESH5.

  In S603, when it is determined that GYRO_DATA is smaller than -IN_THRESH5, the panning control circuit 112 determines that the panning operation has been started in the imaging apparatus, and the process proceeds to S605 and S606. In S605, SIGN_FLAG3 is set, and the sign (negative) of the angular velocity data at the start of the panning operation is stored. In S606, the panning control circuit 112 sets a flag PAN_START_FLAG indicating that the panning operation has been started.

  After the process of S606 is performed, or when it is determined in S603 that GYRO_DATA is equal to or greater than −IN_THRESH5, the panning control circuit 112 ends the process and waits until the start of the next process execution.

  In S601, when PAN_START_FLAG is set, it is determined that the panning operation is being performed, and the panning control circuit 112 proceeds to the process of S607. In step S607, the panning control circuit 112 determines whether or not a flag PAN_CANSEL_FLAG indicating that the panning operation has ended is set. If it is determined that PAN_CANSEL_FLAG is not set, the panning control circuit 112 proceeds to the process of S608.

  In S608, the panning control circuit 112 counts the time PAN_TIME after PAN_START_FLAG is set, and proceeds to the processing of S609.

  In S609, the panning control circuit 112 determines whether SIGN_FLAG3 is set. If it is determined in S609 that SIGN_FLAG3 is set, that is, if the sign of the angular velocity data at the start of the panning operation is negative, the panning control circuit 112 proceeds to the processing of S610.

  In S610, the panning control circuit 112 calculates the minimum value as the peak value of the angular velocity data (GYRO_DATA), which is the output of the A / D converter 14 while it is determined that the panning operation is being performed, and sets it to the variable GYRO_PEAK. The process proceeds to S611.

  In S611, the panning control circuit 112 determines whether GYRO_DATA has become zero or more. If it is determined in S611 that GYRO_DATA has become zero or more, the panning control circuit 112 proceeds to the processing of S614, and sets a flag PAN_CANSEL_FLAG indicating that the panning operation has ended.

  If it is determined in S609 that SIGN_FLAG3 is not set, that is, if the sign of the angular velocity data at the start of the panning operation is positive, the panning control circuit 112 proceeds to the process of S612. In S612, the panning control circuit 112 calculates the maximum value as the peak value of the angular velocity data (GYRO_DATA), which is the output of the A / D converter 14 while it is determined that the panning operation is being performed, and sets it as a variable GYRO_PEAK. Move on to processing.

  In S613, the panning control circuit 112 determines whether GYRO_DATA has become zero or less. If it is determined in S613 that GYRO_DATA has become zero or less, the panning control circuit 112 proceeds to the processing of S614, and sets a flag PAN_CANSEL_FLAG indicating that the panning operation has ended.

  After the process of S614, or after it is determined in S611 that GYRO_DATA is less than zero, or in S613, it is determined that GYRO_DATA is greater than zero, the panning control circuit 112 ends the process and waits for the start of the next process. .

If PAN_CANSEL_FLAG is set in S607, it is determined that the panning operation has been completed, and the panning control circuit 112 proceeds to the process of S615.
In S615, the panning control circuit 112 counts the time CANCEL_TIME after PAN_CANSEL_FLAG is set, and proceeds to the process of S616.

  In S616, the panning control circuit 112 calculates a value of OFFSET_CANCEL that is a signal value set to the output of the offset change circuit 106 in order to remove a signal component that is included in the angular velocity data and shakes in the direction opposite to panning. A calculation method of OFFSET_CANCEL will be described with reference to FIG.

The panning control circuit 112 determines the value of OFFSET_CANCEL according to the time CANCEL_TIME after the panning operation is ended, the time PAN_TIME after the panning operation is started, and the peak GYRO_PEAK value of the angular velocity data during the panning operation. Parameters that are determined according to CANCEL_TIME are OFFSET_CANCEL_ORIGINAL, parameters that are determined according to PAN_TIME are PAN_TIME_GAIN, and parameters that are determined according to GYRO_PEAK are GYRO_PEAK_GAIN. At this time, the panning control circuit 112 calculates the value of OFFSET_CANCEL by the following (Formula 2).
OFFSET_CANCEL = OFFSET_CANCEL_ORIGINAL × PAN_TIME_GAIN × GYRO_PEAK_GAIN (Formula 2)

  FIG. 17A is a diagram illustrating a relationship between time CANCEL_TIME after the panning operation is finished and OFFSET_CANCEL_ORIGINAL. The value of OFFSET_CANCEL_ORIGINAL increases toward CANCEL_PEAK until the value of CANCEL_TIME reaches PEAK_TIME (first predetermined time). The value of OFFSET_CANCEL_ORIGINAL gradually decreases after PEAK_TIME has elapsed (after the first predetermined time has elapsed) until the value of CANCEL_TIME reaches CANCEL_END (second predetermined time). The value of OFFSET_CANCEL_ORIGINAL becomes zero when CANCEL_TIME becomes CANCEL_END. Note that FIG. 17A has a temporal characteristic approximated to the temporal change of the angular velocity data in the swing-back period shown in FIG. CANCEL_ORIGINAL can be prepared by measuring the temporal change of angular velocity data during the swing-back period in advance and approximating it. Note that the relationship shown in FIG. 17A is stored as table data in a non-volatile memory included in the imaging device or panning control circuit 112 in which the shake correction device 100 is mounted, as in the case of the various thresholds and parameters described above. be able to. Alternatively, only OFFSET_CANCEL_ORIGINAL values at typical timings such as PEAK_TIME, CANCEL_END, and CANCEL_PEAK in FIG. 17A may be stored in the nonvolatile memory, and values at other timings may be calculated by interpolation.

  FIG. 17B is a diagram illustrating a relationship between PAN_TIME and PAN_TIME_GAIN. PAN_TIME_GAIN is a coefficient by which OFFSET_CANCEL_ORIGINAL is multiplied. Until PAN_TIME becomes larger than the threshold value TIME_THRESH, the value of PAN_TIME_GAIN is set to zero. When PAN_TIME is larger than the threshold value TIME_THRESH and less than TIME_MAX (below the tenth threshold value), the value of PAN_TIME_GAIN is increased as the value of PAN_TIME is larger. When PAN_TIME becomes larger than the tenth threshold value TIME_MAX, the value of PAN_TIME_GAIN is fixed at the maximum value 1.

  FIG. 17C is a diagram showing the relationship between GYRO_PEAK and GYRO_PEAK_GAIN. GYRO_PEAK_GAIN is a coefficient by which OFFSET_CANCEL_ORIGINAL is multiplied as in PAN_TIME_GAIN. When the absolute value of GYRO_PEAK is smaller than the panning start determination angular velocity threshold IN_THRESH5 (less than the eleventh threshold), the value of GYRO_PEAK_GAIN is set to zero. When GYRO_PEAK is greater than IN_THRESH5 and smaller than GYRO_PEAK_MAX, the value of GYRO_PEAK_GAIN is increased as GYRO_PEAK is increased. For GYRO_PEAK_MAX and above, GYRO_PEAK_GAIN is fixed at a maximum value of 1. When GYRO_PEAK is −IN_THRESH5 or less and greater than −GYRO_PEAK_MAX, the value of GYRO_PEAK_GAIN is decreased as GYRO_PEAK is decreased. When GYRO_PEAK is equal to or less than -GYRO_PEAK_MAX, GYRO_PEAK_GAIN is fixed at the minimum value -1.

  OFFSET_CANCEL is set as an output signal of the offset changing circuit 106 in FIG. As a result, the result obtained by canceling the signal component of the swingback that appears in the direction opposite to the angular velocity of panning included in the output of the HPF 15 at the end of panning by the output signal of the offset changing circuit 106 can be input to the integrator 16. , Can prevent the swing back phenomenon.

  Here, the characteristics of the magnitude of the signal component that swings in the direction opposite to the panning included in the output of the HPF 15 will be described with reference to FIG. FIG. 16B is a diagram showing a change with time of angular velocity data when three kinds of panning operations are performed. As shown by the solid line (1) and the dotted line (2) in FIG. 16B, the peak of angular velocity data at the time of panning operation is smaller than that of (1) (2), and the signal generated by the swing back also occurs. Get smaller. Therefore, as shown in FIG. 17C, by changing the magnitude of GYRO_PEAK_GAIN according to the peak GYRO_PEAK of the angular velocity data during the panning operation, the value of OFFSET_CANCEL is similar to the actual swingback component. Can be.

  Further, in FIG. 16B, when the solid line (1) and the alternate long and short dash line (3) having different durations of the panning operation are compared, the swing back component having the longer duration (3) has a larger value. Therefore, as shown in FIG. 17B, by changing the size of PAN_TIME_GAIN according to the time PAN_TIME from the start to the end of the panning operation, the value of OFFSET_CANCEL is set to a size similar to the actual shakeback signal component. can do.

  After calculating OFFSET_CANCEL in S616, the panning control circuit 112 proceeds to the process of S617. In S617, the panning control circuit 112 determines whether or not CANCEL_TIME counted in S615 is equal to or greater than the time CANCEL_END at which the shakeback signal component converges to zero. If it is determined in S617 that CANCEL_TIME is equal to or greater than CANCEL_END, the panning control circuit 112 proceeds to the processes of S618 and S619 in order to end the process of removing the shakeback signal component generated in the direction opposite to the panning. In S618, the panning control circuit 112 sets OFFSET_CANCEL to zero, and in S619, PAN_CANSEL_FLAG and PAN_START_FLAG are reset.

  After the process of S619 or when it is determined in S617 that CANCEL_TIME is smaller than CANCEL_END, the panning control circuit 112 ends this process and waits until the next process starts.

  Next, the effectiveness of panning control in this embodiment will be described with reference to FIG. 18 (a) and 18 (b) show the time lapse of the angular velocity data (GYRO_DATA) and the low-frequency cut-off frequency of the HPF 15 when the panning operation is performed by the imaging device equipped with the conventional shake correction device. Showing change. FIG. 18 (c) shows a time-lapse of the output (OFFSET_CANCEL) of the offset changing circuit 106 when a panning operation similar to that in FIG. 18 (a) is performed in the imaging apparatus equipped with the shake correction apparatus in the present embodiment. Showing change.

  FIG. 18A shows angular velocity data that is an output of the A / D converter 14 of FIG. 19 or FIG. 1 from the start of the panning operation until the shakeback signal component generated after the end of the panning operation converges to zero. The time-dependent change of is shown. FIG. 18B shows a change with time of the low-frequency cutoff frequency of the HPF 15 from the start of the panning operation described above until the shakeback signal component of the angular velocity data generated after the end of the panning operation converges to zero. FIG. 18C shows the change with time of the output of the offset changing circuit 106 until the swing-back signal component of the angular velocity data converges to zero after the panning operation is completed. Although not shown in FIG. 18 (c), the output of the offset changing circuit 106 during the panning operation is as shown in FIG. 5 (b) and FIG. 7 (c).

  In the conventional panning control, it is determined that the panning operation is started at time T71 when the magnitude of the angular velocity data exceeds IN_THRESH5 in FIG. Then, as shown in FIG. 18B, the low frequency cutoff frequency of the HPF 15 is increased from time T71. Thereafter, it is determined that the panning operation is completed at time T72 when the sign of the angular velocity data is reversed in FIG. After it is determined that the panning operation has been completed, the low frequency cutoff frequency of the HPF 15 is gradually returned to the original value. Further, in order to attenuate the swing-back signal component after the end of the panning operation, the low frequency cutoff frequency of the HPF 15 is held at a constant value without decreasing it to the minimum value (original value) until time T63. Then, after time T63, the low frequency cutoff frequency of the HPF 15 is lowered again and returned to the minimum value (original value) at time T64.

  According to such panning control, it is possible to prevent movement of the captured image due to the swingback signal component by attenuating the swingback signal component after the end of the panning operation by the HPF 15. However, as described above, if the low frequency cutoff frequency of the HPF 15 is kept high, the HPF 15 also attenuates the blur component to be corrected. As a result, the remaining blur amount increases from time T72 to T64 after the end of panning.

  On the other hand, the panning control circuit 112 according to the present embodiment is the same as the conventional one in that the start of the panning operation is determined at time T71 when the magnitude of the angular velocity data exceeds IN_THRESH5 in FIG. However, after that, the panning control circuit 112 continues the calculation of GYRO_PEAK and the count of PAN_TIME shown in FIG. 18A at regular intervals until time T72 when the sign of the angular velocity data is inverted. If the panning control circuit 112 determines that the panning operation has been completed at time T72, it calculates OFFSET_CANCEL according to the calculation formula (Equation 2) and outputs it from the offset change circuit 106 until time T73.

  By subtracting OFFSET_CANCEL from the output of the HPF 15 by the adder / subtractor 108, it is possible to efficiently suppress the shakeback signal component generated after the end of the panning operation, and to suppress the movement of the captured image due to the shakeback. . According to the method of the present embodiment, the low frequency cut-off frequency of the HPF 15 is not changed, so that the shake signal component of the angular velocity data generated after the end of the panning operation without attenuating the shake component to be corrected from the shake correction data. Can be removed.

  As described above, according to the present embodiment, the angular velocity data generated after the end of the panning operation while avoiding the phenomenon that the amount of remaining blur generated by the panning control for changing the low-frequency cutoff frequency of the conventional HPF 15 is increased. Can be effectively suppressed.

  In this embodiment, the output of the A / D converter 14 is used to determine the start and end of the panning operation and the OFFSET_CANCEL value is calculated. However, the same determination and calculation are performed using the output data of the HPF 15. It can be performed.

  Moreover, when calculating the value of OFFSET_CANCEL, the value of the peak GYRO_PEAK of the angular velocity data during the panning operation is used, but the present invention is not limited to this. For example, the same effect can be obtained by using the average value of the angular velocity data during the panning operation instead of the peak of the angular velocity data.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary. It is also possible to implement a combination of a plurality of embodiments.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (6)

  1. Shake detection means for detecting shake;
    Calculation means for calculating first image shake correction data based on an output of the shake detection means ;
    Panning detection means for detecting whether it is a panning operation based on the output of the shake detection means;
    Offset value generating means for generating an offset value to subtract from the first image blur correction data;
    A blur correction unit that corrects image blur using second image blur correction data obtained by subtracting the offset value from the first image blur correction data when a panning operation is detected by the panning detection unit;
    An imaging device having
    The offset value is data for returning the shake correction unit approaching the correction end of the shake correction unit to the correction center of the shake correction unit,
    The image pickup apparatus, wherein the offset value when the zooming speed of the photographing optical system is equal to or higher than a predetermined value is larger than the offset value when the zooming speed is smaller than the predetermined value.
  2. Further comprising a focal length detection means for detecting a focal length of the photographing optical system,
      The offset value when the focal length of the photographing optical system is greater than or equal to a predetermined value is smaller than the offset value when the focal length of the photographing optical system is smaller than the predetermined value. Imaging device.
  3. When the panning operation is detected by the panning detection unit, the offset value when the distance to the correction end of the shake correction unit is a predetermined value or more is the distance to the correction end of the shake correction unit. The imaging apparatus according to claim 1, wherein the imaging apparatus is smaller than the offset value when the value is smaller.
  4. A shake detection step of detecting a Re vibration,
    A calculation step of calculating a first image blur correction data based on the output of the previous SL shake detection step,
    A panning detection step for detecting whether or not it is a panning operation based on the output of the shake detection step;
    An offset value generating step for generating an offset value to subtract from the first image blur correction data;
    When a panning operation is detected in the panning detection step, a shake correction step of correcting image shake by a shake correction unit using second correction data obtained by subtracting the offset value from the first image shake correction data. When,
    A method for controlling an imaging apparatus having:
    The offset value is data for returning the shake correction unit approaching the correction end of the shake correction unit to the correction center of the shake correction unit,
    The control method of an imaging apparatus, wherein the offset value when the zooming speed of the photographing optical system is equal to or higher than a predetermined value is larger than the offset value when the zooming speed is smaller than the predetermined value.
  5. A focal length detecting step of detecting a focal length of the photographing optical system;
      The offset value when the focal length of the photographing optical system is greater than or equal to a predetermined value is smaller than the offset value when the focal length of the photographing optical system is smaller than the predetermined value. Method for controlling the imaging apparatus.
  6. The offset value when the distance to the correction end of the shake correction unit is a predetermined value or more is smaller than the offset value when the distance to the correction end of the shake correction unit is smaller than the predetermined value. The control method of the imaging device according to claim 4.
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