JP5848603B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to a technique for correcting image blur caused by shake of an imaging apparatus by using both an optical camera shake correction system and an electronic camera shake correction system in an imaging apparatus.

  In recent years, with the downsizing of imaging devices and the increase in the magnification of optical systems, attention has been paid to the fact that shakes in the imaging devices are a major cause of degrading the quality of captured images. Various blur correction functions for correcting shake of captured images have been proposed. As a conventional blur correction function installed in an imaging apparatus, there is a correction method using both a photo-optical camera shake correction method and an electronic camera shake correction method only during electronic zoom (see, for example, Patent Document 1).

  First, in the optical camera shake correction method, the shake of the imaging device is detected, and the optical system for camera shake correction is driven so as to cancel the detected shake, and the subject light incident on the image sensor is imaged. The shake is corrected so that it is always the same position on the surface. Next, in the electronic camera shake correction method, image blur is detected so as to detect a shake remaining that cannot be corrected by the optical camera shake correction method and cancel out the shake between the obtained images. By moving the reading area of, the unbalanced low frequency is corrected. Note that the range in which the image reading area can be moved is a range of surplus pixels generated when the electronic zoom is performed. Thus, the correction performance can be improved by using the optical camera shake correction method and the electronic camera shake correction method in combination.

JP-A-11-146260

  In recent years, in the technical field of camera shake correction, a technique for correcting not only fine camera shake caused by hand tremor on the telephoto side but also correcting body shake during walking on the wide angle side has become widespread. Along with this, it is desired to perform optimal image stabilization control in all zoom ranges from the wide-angle side to the telephoto side. For this reason, it is difficult to say that the image stabilization control is optimal when the optical camera shake correction and the electronic camera shake correction are used together only during the electronic zoom as in the prior art.

  The present invention has been made in view of the above problems, and in a shake correction method using both optical camera shake correction and electronic camera shake correction, the camera shake correction control is performed according to the zoom position, and the lens is reduced in size. It aims to become.

In order to achieve the above object, an image pickup apparatus according to the present invention is an image pickup means for picking up a subject image formed by an optical system, a zoom detection means for detecting a zoom position of a zoom lens, and a shake of the apparatus. A shake detection unit that detects a motion vector from an image captured by the imaging unit, a first acquisition unit that obtains a first shake correction amount based on the shake, and a motion vector. Based on a second acquisition means for obtaining a second shake correction amount, on the basis of the first shake correction amount, a first correction means for optically correcting image blur due to the shake; A second correction unit that corrects image blur due to the shake by changing a cutout range of the image based on a shake correction amount of 2, and a zoom position of the zoom lens does not include the wide-angle end and the telephoto end. If within range determined order, and a control means for controlling so as to win suppress the first shake correction amount and the second shake correction amount than in the outside of said range.

  According to the present invention, in the camera shake correction method using both optical camera shake correction and electronic camera shake correction, it is possible to perform camera shake correction control according to the zoom position and to reduce the size of the lens.

1 is a block diagram illustrating an example of a configuration of an imaging device according to an embodiment of the present invention. 5 is a flowchart of processing performed by a zoom control change unit according to the embodiment. The graph for demonstrating the process in S100 and S101 of FIG. 6 is a graph for explaining a relationship between a zoom magnification and an image circle diameter of a lens in the embodiment. The graph for demonstrating the process in S102 and S103 of FIG. The graph for demonstrating the blurring correction control at the time of wide angle walk imaging | photography in embodiment. The graph for demonstrating the blurring correction control at the time of telephoto still photography in an embodiment.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings. In the following description, description will be made regarding blur correction control in either the horizontal direction or the vertical direction of the image, and the blur correction control in the other direction is the same control, and thus description thereof is omitted.

  FIG. 1 is a block diagram showing a configuration of a video camera as an example of an imaging apparatus according to the first embodiment of the present invention. Hereinafter, each component of the imaging apparatus 100 in FIG. 1 and an example of the operation thereof will be described in detail.

  The angular velocity sensor 102 (shake detection means) detects a shake applied to the imaging apparatus 100 as an angular velocity signal, and supplies the angular velocity signal to the A / D converter 103. The A / D converter 103 digitizes the angular velocity signal from the angular velocity sensor 102 and supplies it to the HPF 104 inside the μCOM 101 as angular velocity data. The HPF 104 has a function of changing the characteristics in an arbitrary frequency band, and outputs a signal in the high frequency band by cutting off the low frequency component included in the angular velocity data from the A / D converter 103. The HPF 104 subtracts a signal that has passed through a filter (LPF) that cuts off a signal in the high frequency band from the output of the A / D converter 103 from the output of the A / D converter 103. Good.

  The imaging optical system 115 performs operations such as zooming and focusing, and forms a subject image on the imaging element 117. The zoom encoder 116 (zoom detection means) detects the zoom position (magnification position) of the zoom lens included in the imaging optical system 115 and outputs it to the focal length calculation unit 105 in the μCOM 101. The focal length calculation unit 105 calculates the focal length of the imaging optical system 115 from the output of the zoom encoder 116 and corrects the output of the HPF 104 so as to be an optimum value for driving the correction optical system 114.

  The integrator 106 has a function capable of changing its characteristic in an arbitrary frequency band, integrates the output from the focal length calculation unit 105, and drives the correction optical system 114 (optical correction data, first correction data). (Shake correction amount) is calculated. That is, the A / D converter 103, the HPF 104, the focal length calculation unit 105, and the integrator 106 form a first acquisition unit. The optical correction data output limiting unit 131 (first output limiting unit) limits the output of the integrator 106 so that the correction optical system 114 is driven within the movable range determined by the zoom control changing unit 130.

  The subtractor 107 A / D converts the output of the position detection unit 112 that detects the position of the correction optical system 114 by the A / D converter 113, and digitizes the data from the output of the optical correction data output restriction unit 131. The deviation data obtained as a result of the subtraction is supplied to the control filter 108. The control filter 108 includes an amplifier that amplifies input data with a predetermined gain, and a phase compensation filter. The deviation data supplied from the subtracter 107 is subjected to signal processing by the amplifier and the phase compensation filter in the control filter 108 and then output to the pulse width modulation unit 109.

  The pulse width modulation unit 109 modulates the data supplied through the control filter 108 into a waveform (that is, a PWM waveform) that changes the duty ratio of the pulse wave, and supplies the modulated data to the motor driving unit 110. The motor 111 is a voice coil type motor for driving the correction optical system 114, and is driven by the motor driving unit 110 to move the correction optical system 114 in a direction perpendicular to the optical axis. The position detection unit 112 includes a magnet and a hall sensor provided at a position facing the magnet, detects the amount of movement of the correction optical system 114 in the direction perpendicular to the optical axis, and converts the detection result into A / D conversion. This is supplied to the subtractor 107 described above via the device 113. As a result, a feedback control system is configured in which the amount of movement of the correction optical system 114 in the direction perpendicular to the optical axis follows the output of the optical correction data output restriction unit 131.

  The correction optical system 114 is, for example, a shift lens, and is a correction system capable of optical shake correction that deflects the optical axis by being moved in a direction perpendicular to the optical axis (first correction means). As a result, an image in which the movement of the subject on the imaging surface caused by the shake of the apparatus is corrected is formed on the imaging element 117.

  The imaging element 117 converts the subject image formed by the imaging optical system 115 into an electrical signal as a captured image signal and supplies the electrical signal to the signal processing unit 118. The signal processing unit 118 generates a video signal (video signal) compliant with, for example, the NTSC format from the signal obtained by the image sensor 117 and supplies it to the motion vector detection unit 125 and the image memory 119.

  Based on the luminance signal included in the current video signal generated by the signal processing unit 118 and the luminance signal included in the video signal of the previous field stored in the image memory 119, the motion vector detection unit 125 The motion vector is detected. The motion vector data detected by the motion vector detection unit 125 is supplied to the HPF 128 (high-pass filter) inside the μCOM 101. Note that “A” indicated by 126 and 127 in FIG. 1 indicates that a signal flows from “A” 126 to “A” 127.

  The HPF 128 has a function of changing the characteristics in an arbitrary frequency band, and outputs a signal in a high frequency band by cutting off a low frequency component included in the motion vector data. The HPF 128 may be configured to subtract, from the output of the motion vector detection unit 125, a signal that has passed through a filter (LPF) that blocks a signal in the high frequency band from the output of the motion vector detection unit 125. The integrator 129 has a function of changing its characteristics in an arbitrary frequency band, and integrates the output from the HPF 128. Then, control amounts (electronic correction data and second shake correction data) for controlling the image reading position of the image memory 119 are calculated so that the image blur is offset. That is, the HPF 128 and the integrator 129 form a second acquisition unit. The electronic correction data output limiting unit 132 (second output limiting unit) integrates the integrator 129 so that the range of the image reading position in the image memory 119 is set within the range determined by the zoom control changing unit 130. Limit the output of. That is, the zoom control changing unit 130, the optical correction data output limiting unit 131, and the electronic correction data output limiting unit 132 constitute a control unit.

  The memory read control unit 120 determines the read position of the image from the image memory 119 according to the control amount calculated by the electronic correction data output restriction unit 132 (second correction unit). As a result, a video signal whose blur has been corrected electronically is output from the image memory 119. The memory read control unit 120 further outputs a video signal to the display control unit 121 and causes the display device 122 to display an image. The display control unit 121 drives the display device 122, and the display device 122 displays an image by a liquid crystal display element (LCD) or the like. Further, the memory read control unit 120 outputs the video signal to the recording control unit 123 and records it on the recording medium 124 when the recording of the video signal is instructed by an operation unit (not shown) used for instructing start or end of recording. . The recording medium 124 is a magnetic recording medium such as a hard disk or an information recording medium such as a semiconductor memory.

  The zoom control changing unit 130 changes the control of the optical correction data output limiting unit 131, the electronic correction data output limiting unit 132, the HPF 128, and the integrator 129 based on the output of the zoom encoder 116.

  Next, processing executed by the zoom control change unit 130 in the present embodiment will be described in detail with reference to the drawings. FIG. 2 is a flowchart showing a process flow of the zoom control change unit 130. The processing of the flowchart of FIG. 2 is repeatedly performed at intervals of, for example, 1/60 second.

  In S <b> 100, the zoom control change unit 130 calculates an optical correction data limit value OPT_LIMIT (first limit value) based on the output of the zoom encoder 116, and sets it in the optical correction data output limit unit 131. By setting this limit value, even if the output of the integrator 106 exceeds OPT_LIMIT, the optical correction data output limit unit 131 outputs the optical correction data limit value OPT_LIMIT. Accordingly, it is possible to limit the optical correction data so that the correction optical system 114 is driven within the movable range determined by the zoom control change unit 130.

  A method for calculating the optical correction data limit value OPT_LIMIT will be described with reference to the graph of FIG. In FIG. 3A, the horizontal axis indicates the zoom magnification of the imaging apparatus 100 calculated from the output of the zoom encoder 116, and the vertical axis indicates the value of the optical correction data limit value OPT_LIMIT. When the zoom magnification is at the wide-angle end, the optical correction data limit value OPT_LIMIT is set to WIDE_OPT_LIMIT. Then, as the zoom magnification increases from the wide-angle end to the magnification ZOOM_1 (out of range), the optical correction data limit value OPT_LIMIT is reduced to MIDD_OPT_LIMIT (<WIDE_OPT_LIMIT), thereby reducing the suppression effect. When the zoom magnification is from ZOOM_1 to ZOOM_2 (within range), the optical correction data limit value OPT_LIMIT is fixed at MIDD_OPT_LIMIT to suppress the vibration suppression effect. Then, as the zoom magnification increases from the magnification ZOOM_2 to the telephoto end (out of range), the optical correction data limit value OPT_LIMIT is increased to TELE_OPT_LIMIT (> MIDD_OPT_LIMIT), thereby increasing the suppression effect.

  The reason why the optical correction data limit value OPT_LIMIT is calculated as shown in FIG. 3A will be described below. Assuming that the shake angle applied to the imaging apparatus 100 is θ and the focal length of the imaging apparatus 100 is f, the blur amount on the imaging element 117 is approximated by ftanθ. In other words, in order to correct the same shake angle, a larger amount of blur correction is required toward the telephoto side. The sensitivity of the correction optical system 114 is defined as the ratio of the distance that the correction optical system 114 has moved in the direction perpendicular to the optical axis and the movement distance of the subject on the image sensor 117 when the correction optical system 114 has moved. The sensitivity of the correction optical system 114 does not change much depending on the zoom magnification. Therefore, the amount of movement of the correction optical system 114 for correcting the predetermined shake angle becomes larger as the distance is on the telephoto side. This is why the optical correction data limit value OPT_LIMIT is increased as the zoom magnification increases from ZOOM_2 to the telephoto end in FIG.

  On the other hand, the shake applied to the imaging apparatus 100 when the user is shooting while walking is very large compared to the shake when the user is stationary. As described above, when the shake angle applied to the imaging apparatus 100 is θ, the shake amount on the image sensor 117 is approximated by ftanθ. Therefore, when the focal length f is small near the wide-angle end, even if θ increases during walking, the amount of movement of the correction optical system 114 for performing blur correction is not so large. However, if it is attempted to correct the shake during walking even when the focal length is large, it is necessary to increase the amount of movement of the correction optical system 114 in proportion to the focal length f, leading to an increase in the size of the lens. In order to prevent this, shake correction during walking is limited only to the vicinity of the wide-angle end, and at the wide-angle end, the value of the optical correction data limit value OPT_LIMIT is increased as shown in FIG. Then, as the zoom magnification increases from the wide-angle end to ZOOM_1, the optical correction data limit value OPT_LIMIT is reduced to reduce the vibration suppression effect.

  When the zoom magnification is between ZOOM_1 and ZOOM_2, the optical correction data limit value OPT_LIMIT is fixed at the minimum value MIDD_OPT_LIMIT to suppress the vibration suppression effect. This is because, in a zoom region where no blurring correction is performed during walking and the focal length is short, there is no need to increase the amount of movement of the correction optical system 114, and further by reducing the amount of movement of the correction optical system 114, This is because the diameter of the image circle can be reduced, contributing to the downsizing of the lens.

  Returning to FIG. 2, after the process of S100, the process proceeds to S101. In S <b> 101, the zoom control changing unit 130 calculates an electronic correction data limit value ELEC_LIMIT (second limit value) based on the output of the zoom encoder 116, and sets it in the electronic correction data output limiting unit 132. By setting this limit value, even if the output of the integrator 129 exceeds ELEC_LIMIT, the electronic correction data output limit unit 132 outputs the electronic correction data limit value ELEC_LIMIT. As a result, the electronic correction data is limited so that the range of the image reading position in the image memory 119 is set within the range determined by the zoom control change unit 130.

  Here, a method of calculating the electronic correction data limit value ELEC_LIMIT will be described with reference to the graph of FIG. In FIG. 3B, the horizontal axis indicates the zoom magnification of the imaging apparatus 100 calculated from the output of the zoom encoder 116, and the vertical axis indicates the value of the electronic correction data limit value ELEC_LIMIT. When the zoom magnification is at the wide-angle end, ELEC_LIMIT is set to WIDE_ELEC_LIMIT (> 0), and as the zoom magnification increases from the wide-angle end to the magnification ZOOM_1 (out of range), ELEC_LIMIT is reduced to 0 to reduce the suppression effect. Go. When the zoom magnification is from ZOOM_1 to ZOOM_2 (within range), the ELEC_LIMIT value is fixed at 0 to suppress the vibration suppression effect. As the zoom magnification increases from the magnification ZOOM_2 to the telephoto end (out of range), the electronic correction data limit value ELEC_LIMIT is increased to TELE_ELEC_LIMIT (> 0), thereby increasing the suppression effect.

  The reason why the electronic correction data limit value ELEC_LIMIT is calculated as shown in FIG. 3B will be described below. As described above, in order to correct the same shake angle, a larger blur correction amount is required as the distance is increased. At this time, a blur remaining that cannot be corrected by the correction optical system 114 also increases. In order to correct this blur remaining, in FIG. 3B, as the zoom magnification increases from ZOOM_2 to the telephoto end, the electronic correction data limit value ELEC_LIMIT is increased to increase the vibration suppression effect. .

  On the other hand, as described above, shake correction during walking is performed near the wide-angle end. At the time of walking, a large vibration is applied to the imaging device 100 as compared with the stationary state. As a result, the correction optical system 114 also vibrates, causing a phenomenon that the image vibrates in accordance with the vibration during walking. In order to correct this image vibration, in FIG. 3B, the electronic correction data limit value ELEC_LIMIT is increased when the zoom magnification is at the wide angle end, thereby reducing the suppression effect. By reducing the value of the electronic correction data limit value ELEC_LIMIT when the zoom magnification is between the wide-angle end and ZOOM_1 and fixing it to 0 between ZOOM_1 and ZOOM_2, the suppression effect is suppressed. This is because the image circle diameter of the lens can be reduced as in the case of reducing the movement amount of the correction optical system 114, which contributes to the miniaturization of the lens.

  FIG. 4 is a graph in which the horizontal axis indicates the zoom magnification of the imaging apparatus 100 and the vertical axis indicates the image circle diameter of the lens. As shown in FIG. 4, the image circle diameter when the zoom magnification is at the wide angle end is WIDE_IMAGE_HEIGHT. As described above, the blur correction range is set to be small from the zoom magnifications ZOOM_1 to ZOOM_2 in FIGS. 3 (a) and 3 (b). Therefore, as shown in FIG. 4, in ZOOM_5 between ZOOM_1 and ZOOM_2, the image circle diameter can be set to MIDD_IMAGE_HEIGHT smaller than WIDE_IMAGE_HEIGHT. From ZOOM_5 to the telephoto end, the image circle diameter extends to TELE_IMAGE_HEIGHT (> MIDD_IMAGE_HEIGHT). In general, what determines the lens size is not the image circle diameter in the zoom area on the telephoto side, but the image circle diameter in the zoom area near the wide angle. Therefore, as shown in FIG. 4, if the image circle diameter can be reduced with the zoom magnification ZOOM_5 closer to the wide angle, the lens can be reduced in size.

  Returning to FIG. 2, after the process of S101, the process proceeds to S102. In S102, the zoom control changing unit 130 calculates the cutoff frequency ELEC_HPF_FC of the HPF 128 based on the output of the zoom encoder 116, and sets the filter coefficient so that the cutoff frequency of the HPF 128 becomes ELEC_HPF_FC.

  Here, a method for calculating the cut-off frequency ELEC_HPF_FC will be described with reference to the graph of FIG. In FIG. 5A, the horizontal axis indicates the zoom magnification of the imaging apparatus 100 calculated from the output of the zoom encoder 116, and the vertical axis indicates the value of the cutoff frequency ELEC_HPF_FC. When the zoom magnification is at the wide-angle end, the cutoff frequency ELEC_HPF_FC is WIDE_ELEC_HPF_FC. Then, as the zoom magnification increases from the wide-angle end to the magnification ZOOM_3 (out of range), the suppression effect is reduced by increasing the cutoff frequency ELEC_HPF_FC to MIDD_ELEC_HPF_FC (> WIDE_ELEC_HPF_FC). When the zoom magnification is from ZOOM_3 to ZOOM_4 (within range), the cutoff frequency ELEC_HPF_FC is fixed at MIDD_ELEC_HPF_FC to suppress the suppression effect. Then, as the zoom magnification increases from the magnification ZOOM_4 to the telephoto end (out of range), the cutoff frequency ELEC_HPF_FC is decreased to TELE_ELEC_HPF_FC (<WIDE_ELEC_HPF_FC) to increase the vibration suppression effect. After the process of S102, the process proceeds to S103.

  In S103, the zoom control changing unit 130 calculates the time constant ELEC_INT_T of the integrator 129 based on the output of the integrator 129, and sets the filter coefficient so that the time constant of the integrator 129 becomes ELEC_INT_T.

  Here, a method for calculating the time constant ELEC_INT_T will be described with reference to the graph of FIG. In FIG. 5B, the horizontal axis indicates the zoom magnification of the imaging apparatus 100 calculated from the output of the zoom encoder 116, and the vertical axis indicates the value of the time constant ELEC_INT_T. When the zoom magnification is at the wide-angle end, the time constant ELEC_INT_T is WIDE_ELEC_INT_T. Then, as the zoom magnification increases from the wide-angle end to the magnification ZOOM_3 (out of range), the value of the time constant ELEC_INT_T is reduced to MIDD_ELEC_INT_T (<WIDE_ELEC_INT_T) to reduce the suppression effect. When the zoom magnification is from ZOOM_3 to ZOOM_4 (within range), the value of the time constant ELEC_INT_T is fixed at MIDD_ELEC_INT_T to suppress the suppression effect. Then, as the zoom magnification increases from the magnification ZOOM_4 to the telephoto end, the value of the time constant ELEC_INT_T is increased to TELE_ELEC_INT_T (> WIDE_ELEC_INT_T) (out of range), thereby increasing the suppression effect. After the process of S103, this process ends. Note that there is no problem even if only one of the processes of S102 and S103 is performed and the other process is not performed.

  In FIG. 5A, the cutoff frequency of the HPF 128 is increased between the zoom magnifications ZOOM_3 and ZOOM_4. In FIG. 5B, the time constant of the integrator 129 is decreased between the zoom magnifications ZOOM_3 and ZOOM_4. The reason is as follows. In the zoom range between the wide-angle end and the telephoto end, as shown in FIG. 3B, since the limit value of the electronic correction data output limiting unit 132 is reduced, blur correction by changing the reading position of the image memory 119 is performed. This makes it easier to reach the limit of the reading position. Therefore, by increasing the cutoff frequency of the HPF 128 or decreasing the time constant of the integrator 129, the low frequency large amplitude blur is attenuated and only the high frequency small amplitude blur is corrected.

  However, when the limit value of the electronic correction data output limiting unit 132 is small, even if the output of the integrator 129 is large, the electronic correction data output limiting unit 132 is immediately limited by the electronic correction data output limiting unit 132. No longer. Therefore, in the zoom range between the wide-angle end and the telephoto end, increasing the cutoff frequency of the HPF 128 or decreasing the time constant of the integrator 129 is not an essential requirement in the present invention.

  Next, the effect of the processing of S102 and S103 will be described with reference to FIGS. FIG. 6A is a graph showing a change over time in the amount of shake applied to the imaging apparatus 100 when the user performs shooting while walking with the zoom magnification of the imaging apparatus 100 at the wide-angle end. The dotted line graph in FIG. 6B shows a change with time of the drive position of the correction optical system 114 necessary for correcting 100% of the blur on the imaging surface caused by the shake in FIG. . A solid line graph in FIG. 6B shows a change with time of the position of the correction optical system 114 when the image pickup apparatus 100 in FIG. 1 actually performs blur correction by the correction optical system 114.

  The difference between the solid line graph and the dotted line graph in FIG. 6B is due to the following reason. First, in order to prevent an increase in the size of the lens, the movable range of the correction optical system 114 is made narrower than the maximum value of shake that occurs during walking. For this reason, the vibration suppression rate of the low frequency band is lowered by setting the cutoff frequency of the HPF 104 and the time constant of the integrator 106. By doing so, it is possible to prevent the phenomenon that the correction optical system 114 reaches the movable limit determined by the limit value of the optical correction data output limiting unit 131 and the blur correction is not suddenly effective. For this reason, the solid line graph in FIG. 6B has a smaller amplitude than the dotted line graph, so that the blur in the low frequency band is not corrected. Secondly, as described above, since a large vibration is applied to the imaging apparatus when walking compared to the stationary state, the correction optical system 114 is also vibrated. Accordingly, the solid line graph of FIG. 6B has a waveform in which vibrations in a high frequency band are superimposed as compared with the dotted line graph.

  The dotted line graph of FIG. 6C shows the blur remaining after correcting the blur on the imaging surface caused by the shake of FIG. 6A by driving the correction optical system 114 according to the solid line waveform of FIG. 6B. Is a change with time of the reading position of the image memory 119 for 100% correction. A solid line graph in FIG. 6C shows a change with time of the read position of the image memory 119 when the image pickup apparatus 100 in FIG. 1 actually performs blur correction by the memory read control unit 120.

  In S102 of FIG. 2, as described with reference to FIG. 5A, the cutoff frequency of the HPF 128 at the wide angle end is set higher than that at the telephoto end. In other words, the HPF 128 attenuates the blur component in the low frequency band and outputs the blur in the high frequency band without being attenuated. In S103, as described with reference to FIG. 5B, the time constant of the integrator 129 at the wide-angle end is set smaller than that at the telephoto end. That is, in the integrator 129, the blur component in the low frequency band is attenuated and integrated, and the blur in the high frequency band is integrated and output without being attenuated.

  As a result, the change of the reading position of the image memory 119 with time becomes a waveform shown by the solid line graph in FIG. 6C, and only the vibration component in the high frequency band can be corrected. The reason why the low frequency component blur during walking is not corrected is that the frequency of the low frequency component blur reaches the limit of the reading position of the image memory 119 determined by the limit value of the electronic correction data output limiting unit 132 because the amplitude is large. Because it becomes very large. Further, even if some blur in the low frequency band remains, the image is less uncomfortable, but the image in which the vibration in the high frequency band is generated is an unsightly image, and thus correction is preferable.

  The graph of FIG. 6D shows the image blur remaining after the blur on the imaging surface caused by the shake of FIG. 6A is corrected according to the solid line waveform of FIGS. 6B and 6C. It shows changes over time. As described above, since the vibration in the high frequency band is corrected by changing the reading position of the image memory 119, only the unblurred blur in the low frequency band remains. Accordingly, it is possible to realize optimal blur correction control during wide-angle walking shooting using both optical camera shake correction and electronic camera shake correction.

  FIG. 7A shows a change with time of the amount of shake applied to the imaging apparatus 100 when the user has taken a picture in a state where the zoom magnification of the imaging apparatus is at the telephoto end and the user is stationary (not during walking). It is the graph which showed. The graph in FIG. 7A has a waveform in which a shake in a low frequency band such as a body shake is superimposed on a shake in a high frequency band such as a hand shake.

  FIG. 7B shows a change with time of the position of the correction optical system 114 when the shake correction by the correction optical system 114 is performed. Since a low frequency fluctuation component is generally superimposed on the output of the angular velocity sensor 102, the low frequency component of the output of the angular velocity sensor 102 is attenuated by the HPF 104 or the integrator 106. As a result, the drive amount of the correction optical system 114 has a waveform obtained by removing the low frequency component from the shake amount of FIG. 7A, as shown in FIG. 7B.

  FIG. 7C shows a change with time of the reading position of the image memory 119 when blur correction is performed by the memory reading control unit 120. In S102 of the flowchart of FIG. 2, as described with reference to FIG. 5A, the cutoff frequency of the HPF 128 at the telephoto end is set lower than that at the wide-angle end. That is, the HPF 128 outputs a low frequency band blur component without being attenuated. In S103, as described with reference to FIG. 5B, the time constant of the integrator 129 at the telephoto end is set larger than that at the wide angle end. In other words, the integrator 129 integrates and outputs the blur component from the low frequency band to the high frequency band without being attenuated.

  As a result, the change with time of the reading position of the image memory 119 becomes the waveform shown in FIG. 7C, and the blur component in the low frequency band that is not corrected by the correction optical system 114 can be corrected. The blur on the image plane in the low frequency band when the user performs telephoto shooting in a stationary state is smaller than the blur on the image plane in the low frequency band when the wide angle shooting is performed in the walking state. Therefore, when the blur in the low frequency band is corrected by the memory read control unit 120 in the former, the frequency of reaching the limit of the read position is less than that in the latter. Accordingly, it is preferable to correct the blurring in the low frequency band as compared with the wide-angle side because the blurring is easier to see.

  The graph of FIG. 7D shows the remaining time of image blur remaining after correcting the blur on the imaging surface caused by the shake of FIG. 7A according to the waveforms of FIG. 7B and FIG. 7C. Shows changes due to As described above, since the vibration in the low frequency band is corrected by changing the reading position of the image memory 119, an image with less blur remaining from low frequency to high frequency is obtained. Thereby, it is possible to realize the optimum blur correction control at the time of telephoto still photography using both the optical camera shake correction and the electronic camera shake correction.

  As described above, in the embodiment of the present invention, the control range of the memory read control unit 120 is increased on the wide angle side and the telephoto side, and is decreased in the intermediate zoom range. As a result, it is possible to reduce the size of the lens while improving the blur correction performance during both wide-angle walking shooting and telephoto shooting. On the wide angle side, the cutoff frequency of the HPF 128 is increased or the time constant of the integrator 129 is decreased, and on the telephoto side, the cutoff frequency of the HPF 128 is decreased or the time constant of the integrator 129 is increased. As a result, optimal blur correction control can be realized depending on the zoom range.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. Moreover, you may combine suitably a part of above-mentioned embodiment.

Claims (5)

An imaging means for imaging a subject image formed by the optical system;
Zoom detecting means for detecting a zoom position of the zoom lens;
Shake detection means for detecting the shake of the device;
Vector detection means for detecting a motion vector from an image captured by the imaging means;
First acquisition means for obtaining a first shake correction amount based on the shake;
Second acquisition means for obtaining a second shake correction amount based on the motion vector;
First correction means for optically correcting image blur due to the shake based on the first shake correction amount;
Second correction means for correcting image blur due to the shake by changing a cutout range of the image based on the second shake correction amount;
When the zooming position of the zoom lens is within a predetermined range that does not include the wide-angle end and the telephoto end, the first shake correction amount and the second shake correction amount are greater than when the zoom lens is outside the range. imaging apparatus characterized by a control means for controlling so as to win suppress the.   The control means includes first and second output limiting units that suppress the first shake correction amount and the second shake correction amount, respectively, and the zoom position of the zoom lens is within the range. The imaging apparatus according to claim 1, wherein in some cases, the outputs of the first and second output restriction units are more restricted than in a case where the output is outside the range.   The second acquisition unit includes a high-pass filter, and the control unit sets the cutoff frequency of the high-pass filter when the zooming position of the zoom lens is within the range than when the zoom lens is outside the range. 3. The imaging apparatus according to claim 1, wherein the imaging device is configured to be higher and to have a cutoff frequency at the telephoto end lower than a cutoff frequency at the wide-angle end.   The second acquisition means includes integration means, and the control means increases the time constant of the integration means when the zoom position of the zoom lens is within the range than when the zoom lens is outside the range. The imaging apparatus according to any one of claims 1 to 3, wherein the imaging device is shortened and the time constant at the telephoto end is made longer than the time constant at the wide-angle end. A method for controlling an image pickup apparatus having an image pickup means for picking up a subject image formed by an optical system,
A zoom detection step in which the zoom detection means detects the zoom position of the zoom lens;
A shake detection step in which the shake detection means detects the shake of the imaging device;
A vector detection step of detecting a motion vector from the image captured by the imaging means;
A first acquisition unit that obtains a first shake correction amount based on the shake;
A second obtaining step in which a second obtaining means obtains a second shake correction amount based on the motion vector;
When the zooming position of the zoom lens is within a predetermined range that does not include the wide-angle end and the telephoto end, the control means may detect the first shake correction amount and the first amount more than when the zoom lens is outside the range. and a control step of controlling so as to suppress win the shake correction amount of 2,
A first correction step in which a first correction unit optically corrects the shake based on the suppressed first shake correction amount;
A second correction step, wherein the second correction unit corrects the shake by changing a cutout range of the image based on the suppressed second shake correction amount;
A method for controlling an imaging apparatus , comprising:

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