JP7282598B2 - Control device, imaging device, control method, and program - Google Patents

Description

The present invention relates to an imaging apparatus that performs focus detection using a phase difference detection method.

In recent years, in order to reduce image blurring in hand-held shooting, an imaging device acquires a high-quality image by using an image blurring correction member and controlling the movement of the image blurring correction member according to the image blurring. It has been known. Also, in order to increase the focusing speed in live view photography, an imaging apparatus has been proposed that is capable of phase-difference detection type focus detection by arranging focus detection pixels on the imaging surface of an imaging element. In such an imaging apparatus, accuracy is required for base line length information for converting the amount of image shift obtained by correlation calculation into the amount of focus movement. However, due to the movement of the image blur correction member, the image shift amount may change even though the focus state of the subject does not change.

Japanese Unexamined Patent Application Publication No. 2002-100001 discloses a focus adjustment method that obtains an accurate focus driving amount by correcting base line length information that is changed to a defocus amount for focusing using image shift amount information.

Japanese Patent No. 6210824

However, if the baseline length information is corrected in real time as in Patent Document 1, the load of signal processing increases. Further, if a delay in information transmission occurs, accurate correction cannot be performed, so there is a possibility that malfunction may occur in focus driving. In addition, when the amount of movement of the image blur correction member is large, the length of the base line after correction becomes too short, which may make it difficult to obtain an accurate focus drive amount.

Accordingly, the present invention provides a control device, an imaging device, a control method, and a program capable of suppressing a decrease in focusing speed by reducing errors in the amount of focus driving during image blur correction with a simple configuration. intended to provide

A control device as one aspect of the present invention provides a first image signal obtained from a light flux that has passed through a first pupil region of an imaging optical system, and a light flux that has passed through a second pupil region of the imaging optical system. focus detection means for performing focus detection based on the amount of correlation with a second image signal obtained; calculation means for calculating a focus drive amount for performing focus control based on the result of the focus detection; Correcting means for correcting image blur by moving a correcting member; and Acquiring means for acquiring information about changes in focusing accuracy due to the movement of the image blur correcting member, wherein the correcting means uses the information. The movement of the image blur correction member is controlled, the calculation means calculates the focus drive amount based on the result of the focus detection after the movement control of the image blur correction member , and the information is the focus detection. contains image blur amount information of the subject acquired based on the result of .

Other objects and features of the invention are described in the following embodiments.

According to the present invention, a control device, an imaging device, a control method, and a program capable of suppressing a decrease in focusing speed by reducing errors in the amount of focus driving during image blur correction with a simple configuration. can be provided.

1 is a block diagram of an imaging device according to this embodiment; FIG. FIG. 2 is a pixel array diagram of an imaging device according to the present embodiment; It is a pixel arrangement diagram of an imaging device as a modification of the present embodiment. FIG. 10 is a pixel array diagram of an imaging device as another modified example of the present embodiment; 4 is a characteristic graph showing the relationship between the light-receiving angle of the focus detection pixels and the output signal intensity in the embodiment; 4 is a diagram showing the relationship between the electrical signal state of a pair of focus detection pixel groups and the image shift position in the light receiving angle range of the focus detection pixels in the embodiment; FIG. FIG. 2 is an explanatory diagram of an imaging apparatus that performs image blur correction using a correction lens movement method according to the present embodiment; 7A to 7C are diagrams showing the divided shape of the exit pupil for incident light on the focus detection pixel at the image height HGT and the amount of image shift in a pair of image shift signals corresponding to each state of FIGS. 7A to 7C; FIG. FIG. 2 is an explanatory diagram of an image pickup apparatus that performs image blur correction by moving an image pickup element according to the present embodiment; FIG. 10 is an explanatory diagram of light receiving states of focus detection pixels at respective image heights in the state of FIG. 9A; FIG. 10 is an explanatory diagram of light receiving states of focus detection pixels at respective image heights in the state of FIG. 9B; 4 is a characteristic graph showing the relationship between the light-receiving angle of the focus detection pixel and the output signal intensity after image blur correction in the embodiment. FIG. 10 is a diagram showing the divided shape of the exit pupil incident on the focus detection pixel and the amount of image shift in a pair of image shift signals as the imaging device moves according to the present embodiment. 7 is a graph comparing defocus transition states when an error occurs in base line length information by varying the amount of image blur and the position of the image blur correction member in the present embodiment. 4 is a flow chart showing a control method in this embodiment. 4 is a flow chart showing a control method in this embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, referring to FIG. 1, the configuration of the imaging apparatus according to this embodiment will be described. FIG. 1 is a block diagram of an imaging device 100. As shown in FIG. The imaging device 100 has a lens unit (imaging optical system) 101 . However, the present invention is not limited to an imaging device that is integrally configured with a lens unit, but is applicable to an imaging device that includes a camera body and a lens unit (interchangeable lens) detachable from the camera body. is also applicable. In FIG. 1, since the configuration becomes complicated, the parts such as the exposure adjusting means, the display means, the operation members, etc., which are not closely related to the present embodiment, are omitted.

The image pickup apparatus 100 roughly includes a lens unit portion, a portion for acquiring a captured image, a portion for driving an image blur correction member, a portion for controlling an image blur correction amount based on optical information and position information of the image blur correction member, It includes a portion that performs focus driving based on information from the focus detection portion. In the case where the position of the image blur correction member is unconditionally controlled without using the current position information of the image blur correction member, there is no need for the position information of the image blur correction member.

Image blur correction methods generally include a correction lens group movement method that corrects image blur by decentering all or part of the lens group of the imaging optical system, or a method that moves the image sensor according to blur. There is an image pickup device movement correction method that corrects image blurring by using . FIG. 1 shows an image sensor movement correction method as an example, but a method of controlling the movement amount of an image blur correction member, which will be described later, can also be applied to the correction lens group movement method. When the correction lens group moving method is employed, the image sensor driving means 114 in FIG. In this case, instead of detecting the movement amount of the image pickup element 104, the image pickup element position detection means 115 can detect the movement amount of the moving correction lens group.

Next, the flow of imaging signals will be described. The lens unit 101 has an iris diaphragm 102 for adjusting exposure, and a focus lens group 103 that moves along the optical axis OA (optical axis) to change the imaging position. A subject image (optical image) formed via a lens unit (imaging optical system) 101 is formed on an image sensor 104 . The imaging element 104 is a photoelectric conversion element configured by a CMOS sensor and its peripheral circuits. The image sensor 104 is a two-dimensional single-plate color sensor in which light-receiving pixels of M pixels in the horizontal direction and N pixels in the vertical direction are arranged in a square, and a Bayer array primary color mosaic filter is formed on-chip. As will be described later, the imaging element 104 has focus detection pixels arranged among a plurality of imaging pixels. With such a configuration, the image sensor 104 obtains the first image signal obtained from the light flux that has passed through the first pupil region of the imaging optical system and the light flux that has passed through the second pupil region of the imaging optical system. A second image signal is output.

When the image pickup device 104 receives a subject image, an image pickup device drive unit (not shown) performs photoelectric conversion processing of the image pickup device 104, and the image pickup device 104 outputs a signal. The image signal extraction means 105 shapes the signal output from the image sensor 104, removes unnecessary signals, and extracts the image signal. The recording image generation means 120 generates a recording image (ornamental image signal) based on the image signal acquired from the image signal extraction means 105 . The image signal recording means 121 records the recording image (ornamental image signal) generated by the recording image generating means 120 . The focus detection range determination means 110 determines the area for focus detection based on the focus detection signals on the imaging pixels obtained from the image signal extraction means 105 . Then, the focus detection range determining means 110 transmits the coordinate information (pixel position information) of the image sensor 104 from which the focus detection signal is extracted to the focus accuracy change information acquisition means 107 . Note that the selection of the area for focus detection may be made arbitrarily by the user, or may be automatically selected by the imaging apparatus 100 .

After the focus detection area is determined, the correlation signal extraction means 111 extracts the correlation signal in the focus detection area. Correlation calculation means 116 detects phase difference information (image shift amount or image shift amount information) based on the pair of correlation signals extracted by correlation signal extraction means 111 . The image shift amount detected by the correlation calculation means 116 is transmitted to the image blur amount detection means 106 . Image blur amount detection means 106 determines the amount of image blur of the object in the focus detection area from the amount of image shift (result of focus detection).

Focusing accuracy change information acquisition means 107 uses the focusing accuracy change information, that is, the coordinate information of the focus detection area, the image blur amount information, the entrance pupil information, and the exit pupil information to perform focus detection. It is determined whether the defocus information obtained from the result is accurate. The coordinate information of the focus detection area is the coordinate information of the focus detection area in the image sensor 104, and the image blur amount information is information used for focus detection. The entrance pupil position information is information set by the imaging device 104 related to the characteristics of the imaging device 100 and transmitted from the imaging device light receiving pupil information 108 . The exit pupil information is the exit pupil information of the imaging optical system in the focus detection state transmitted from the imaging optical system exit pupil information 109 .

In the present embodiment, as will be described later, weights are set in advance for factors that cause errors when calculating defocus information and the amounts of the factors. Then, the focus accuracy change information acquisition unit 107 acquires the set weighting amount during focus detection. The image blur correction member drive amount determination unit 112 controls the drive amount of the image blur correction member (the image sensor 104 in this embodiment) using the focus accuracy change information. That is, the image blur correction member drive amount determination unit 112 determines the drive range amount of the image blur correction member for reducing the decrease in focusing speed. At the same time, the image blur correction member driving amount determining means 112 acquires the driving amount information of the image sensor 104 during focus detection from the image sensor position detecting means 115 .

The imaging element driving means 114 determines the driving amount for control based on the driving amount information determined by the image blur correction member driving amount determining means 112, that is, based on the driving amount of the imaging element 104 and the driving amount for correction. The drive amount of the imaging element 104 is controlled using the obtained drive amount. The correlation signal extracting means 111 extracts the signal of the focus detection area based on the correlation signal for focus detection reobtained from the image sensor 104 whose drive amount has been corrected. Correlation calculation means 116 then calculates the amount of image shift using the obtained correlation signal.

The focus drive amount calculation means 117 converts the image shift amount into defocus information using the base line length information 119 suitable for the focus detection state from the obtained image shift amount. The focus drive amount calculation means 117 calculates the focus drive amount of the focus lens group 103 from the defocus information, and transmits the focus drive amount to the focus drive means 118 . The focus drive unit 118 drives the focus lens group 103 based on the focus drive amount to bring it into focus.

After controlling the amount of movement of the image blur correction member using the focus detection pixel signal in the imaging apparatus 100 of the present embodiment, focus driving is performed based on the result of focus detection using the focus detection pixel signal again, and the focusing operation is completed. Description of each process. With the configuration described above, it is possible to perform a focusing operation that prevents a decrease in focus speed due to a decrease in focusing precision that accompanies movement of the image blur correction member during image blur correction.

Next, the configuration and light receiving characteristics of the focus detection pixels used in the image sensor 104 will be described with reference to FIGS. 2 to 4. FIG. FIG. 2 is a pixel array diagram of the image sensor 104 (104a). In FIG. 2, pixels 200 are a plurality of pixels (pixel group) for forming a captured image. Pixels 201 to 204 are a plurality of pixels for focus detection (focus detection pixel group) provided with a light shielding structure inside the plurality of pixels 200 arranged.

In FIG. 2, pixels 201 and 202 arranged in a row in the Y direction are used as phase difference information of a pair of pixel signals as a correlation calculation signal for phase difference detection to obtain a vertical stripe pattern shape in the Y direction. is used to detect the focal position of the subject. For an object having a horizontal stripe pattern in the X direction, pixels 203 and 204 arranged in a row in the X direction in FIG. Detect location.

FIG. 3 is a pixel array diagram of the image sensor 104 (104b) as a modified example. In the arrangement of FIG. 3, two photoelectric conversion units are arranged for one microlens. Here, the vertical direction is the Y direction, and the horizontal direction is the X direction. In FIG. 3, a pixel 301 performs correlation calculation using photoelectric conversion signals of photoelectric conversion units 302 and 303 arranged in the X direction for focus detection of an object with a vertical stripe pattern in the Y direction as phase difference information of a pair of pixel signals. used for The pixel 300 is used to detect the focus of an object with a horizontal stripe pattern in the X direction and perform correlation calculation using the photoelectric conversion signals of the photoelectric conversion units 304 and 305 arranged in the Y direction as phase difference information of a pair of pixel signals. When signals from the pixels 300 and 301 are used as captured image signals (image pickup signals), the electric signals of the photoelectric conversion units 302 and 303 and the electric signals of the photoelectric conversion units 304 and 305 are added.

FIG. 4 is a pixel array diagram of the image sensor 104 (104c) as another modification. In the arrangement of FIG. 4, four photoelectric conversion units are arranged for one microlens. Pixel characteristics such as those described with reference to FIG. 3 can be obtained by changing the electric signal addition method of the four photoelectric conversion units. Here, the vertical direction is the Y direction, and the horizontal direction is the X direction. In FIG. 4, a pixel 400 adds photoelectric conversion signals from photoelectric conversion units 401 and 402 and photoelectric conversion units 403 and 404 arranged in the X direction when performing focus detection on an object with a horizontal stripe pattern in the X direction, and outputs two columns of pixels. A photoelectric conversion signal waveform is used for correlation calculation as phase difference information between a pair of pixel signals. Further, when performing focus detection on an object with a vertical striped pattern in the Y direction, the photoelectric conversion signals of the photoelectric conversion units 401 and 403 and the photoelectric conversion units 402 and 404 arranged in the Y direction are added, and two columns of photoelectric conversion signal waveforms are obtained. It is used for correlation calculation as phase difference information of a pair of pixel signals.

Note that the two addition methods for focus detection in the configuration of FIG. 4 may be divided into blocks on the image sensor 104 and the addition method may be changed. It is also possible to achieve a pixel array structure equivalent to the structure shown in . At this time, since the vertical stripe pattern and the horizontal stripe pattern subject are evaluated simultaneously, subject pattern direction dependence can be reduced (preferably eliminated) in focus detection. Also, the addition method may be switched for all pixels in accordance with the photographing state or chronologically. At this time, since the pixels for focus detection for detecting the focus of the subject in the same pattern direction are dense, it is impossible to detect the subject in the vicinity of the in-focus state if the subject has thin line segments that occur when the pixels for focus detection are sparse. problem can be avoided. In the configuration of FIG. 4, when using the signal for a captured image, the electrical signals of the photoelectric conversion units 401 to 404 may be added.

By using such a structure of the image sensor 104, there is no need to separate a part of the subject image via the imaging optical system into an optical system dedicated to focus detection, unlike the conventional phase difference focus detection method. Therefore, it is possible to perform live view shooting while monitoring the subject image that is received by the image sensor 104 and recorded in real time. As a result, it is possible to implement a phase-difference detection type focus detection means that could not be performed without a subject beam splitting mechanism in conventional moving image photography.

Next, the relationship between the light receiving angle of the focus detection pixels and the signal output characteristics will be described with reference to FIG. FIG. 5 is a characteristic graph showing the relationship between the light receiving angle of each focus detection pixel and the signal intensity. In FIG. 5, the horizontal axis indicates the light receiving angle (degrees) of the focus detection pixel, and the vertical axis indicates the signal intensity ratio with respect to the light receiving angle. Hereinafter, this characteristic will be referred to as pixel pupil intensity distribution. Here, the EA and EB curves in FIG. 5 are signal intensity characteristics with respect to respective light receiving angles of the aforementioned pair of focus detection pixels. E is the intensity characteristic of the imaging signal obtained by adding the signal intensity characteristics EA and EB. The pixel signal amount is the integrated value of the signal intensity in the angle range where each focus detection pixel receives light. The signal shape is related to the light-receiving angle range in this pixel pupil intensity distribution. As will be described later, the light receiving angle range changes depending on the exit pupil position and exit pupil diameter of the imaging optical system.

In the focus detection method of the phase difference detection method, an A image signal waveform and a B image signal waveform, which are correlation signals (hereinafter referred to as A image and B image) of a pair of focus detection pixel groups having the pixel structure as described above, are used. is used to determine the amount of correlation that yields the highest signal correlation. Here, the state in which the A image signal waveform and the B image signal waveform are deviated is assumed to be an image deviation, and the correlation amount is hereinafter referred to as an image deviation amount. Here, the A image signal is obtained by scanning the signal intensity characteristic EA of the pixel pupil intensity distribution diagram, and the B image signal is obtained by scanning the focus detection pixel signal integrated with the signal intensity characteristic EB in the X direction (correlation direction). be.

The amount of image shift is often defined by shifting the relative position of the signal waveforms, superimposing the waveforms, and defining the amount of image shift until the amount of area of the difference portion of the waveforms is minimized. A simpler method is to obtain the respective barycenter positions of the A image signal and the B image signal, and use the distance between the barycenters as the amount of image shift. Hereinafter, in order to facilitate the explanation, the distance between the center-of-gravity positions is assumed to be the amount of image shift.

In order to convert the image shift amount into a specific defocus state, it is common to calculate the defocus amount from the image shift amount using base line length information. When calculating the defocus amount, the pupil separation width of the focus detection pixels paired with the phase difference focus detection image sensor group as described in the explanation of FIGS. It must be stored in the imaging device 100 as long information. At this time, in the in-focus state, the image shift amount at the pupil position substantially matches the baseline length. On the other hand, in an out-of-focus state, the amount of image shift changes substantially in proportion to the amount of defocus. Therefore, the defocus amount is obtained by dividing the base line length from the image shift amount.

Next, with reference to FIG. 6, the above contents will be described. FIG. 6 is a diagram showing the relationship between the electrical signal state of a pair of focus detection pixel groups and the image shift position in the light receiving angle range of the focus detection pixels, which are correlated by defocus changes. In FIG. 6, P indicates the exit pupil position of the imaging optical system, and PO indicates the exit pupil distance. A, B, and C indicate focal positions, and B corresponds to the position of the image sensor 104 (focus position). A is a so-called front focus state, and the defocus amount at that time is DEF1 (negative value). C is a so-called rear focus state, and the defocus amount at that time is DEF2 (plus value).

The focus detection signal (correlation signal) described below is obtained from the imaging pixel structure having the focus detection means as described with reference to FIGS. The exit pupil position P is a position corresponding to the distance from the in-focus position B (exit pupil distance PO). ZA is an image shift amount required to obtain correlation from phase difference information of a pair of pixel signals, which are photoelectric conversion signals of the focus detection pixel group, at the focus position A, which is the front focus state. ZB is the amount of image shift at the in-focus position B, which is the in-focus state. be. ZC is the amount of image shift at the focal position C, which is the rear focus state, and the two correlation signal positions are interchanged with respect to the amount of image shift ZA.

R1 and R2 in FIG. 6 are obtained by back-projecting the signal intensity characteristics of a pair of focus detection pixels with respect to the light receiving angle of the focus detection pixels onto the plane of the exit pupil distance P of the imaging optical system from the focus detection pixels. Then, the position of the center of gravity of each of R1 and R2 is determined from the signal intensity distribution, and the distance between the centers of gravity is defined as the baseline length L. The baseline length L is determined by the aperture value information and the exit pupil distance PO of the imaging optical system, since the exit pupil diameter changes depending on the aperture value information and the exit pupil distance PO of the imaging optical system.

In summary, the baseline length L, the exit pupil distance PO, and the image shift amounts ZA and ZC are
L: PO=ZA: DEF1
L: PO=ZC: DEF2
There is a relationship Therefore, the defocus amount is
DEF1=ZA・PO/L (A)
DEF2=ZC・PO/L (B)
required by

The base line length L is calculated by using the signal output characteristics according to the light receiving angle of the focus detection pixels used in the imaging device 100 . In the present embodiment, a virtual imaging optical system in which a circular aperture obtained with arbitrary aperture value information and an exit pupil distance PO are set in advance is used to calculate the center-of-gravity position of each of the separate regions paired at the pupil position, The distance between the two center-of-gravity positions is acquired as the baseline length L (base-line length information 119). If the output signal intensity with respect to the light receiving angle of the focus detection pixel in the imaging device 100 is known, the baseline length L can be obtained by using an approximation formula that expresses the relationship of the baseline length L with respect to the value of the aperture value information of the imaging optical system and the value of the exit pupil distance PO in advance. It can be stored as a coefficient or a two-dimensional array. Then, the base line length information 119 shown in FIG. 1 is stored in the imaging apparatus 100, the defocus amount is calculated from the image shift amount, and focusing is performed. When actually performing focus driving with a stepping motor or the like, a constant may be used that converts the number of pulses required for focus driving for focusing from the obtained defocus amount. However, when performing image blur correction, due to the influence of the moving image blur correction member, a phenomenon occurs in which the image shift amount changes even though the focus state does not change. This phenomenon will be described below.

2. Description of the Related Art In recent imaging apparatuses, there are the following image blur correction means for correcting image blur by moving an image blur correction member.

(1) An optical image stabilizing method (hereinafter referred to as a correction lens movement method) in which the imaging position is changed by decentering the image blur correction lens group of the whole or a part of the imaging optical system.

(2) A method of moving an image pickup device so as to correct image blurring (hereinafter referred to as an image pickup device movement method).

The change in the amount of image shift related to (1) is mainly caused by the influence of optical vignetting due to decentering of the image blur correction lens group. The change in the amount of image shift related to (2) is determined by the shift arrangement of the microlenses on the imaging optical axis side, which is set according to the principal ray angle condition of the incident light beam entering the imaging device from the exit pupil position of the imaging optical system. This is the cause of the deviation. In the following, the change in the image shift amount due to the above causes will be described in detail.

First, the phenomenon that the amount of image deviation changes in the correction lens moving method of (1) will be described. The light beam vignetting state (light beam vignetting information) can be in various states depending on the outer diameter of the lens constituting the imaging optical system, the effective diameter of the light shielding member, and the arrangement thereof. Further, when the image blur correction lens group performs correction movement, a phenomenon occurs in which the light effective portion of the lens group fluctuates and the light beam vignetting increases. In order to prevent ray vignetting during movement of the correction lens group, it is conceivable to set the outer diameter of the lens group of the correction lens group to a dimension that is large enough to prevent ray vignetting even when the lens group is moved. However, if the outer diameter of the correcting lens group is increased, the size of the correcting lens group and its holding member is increased, and the weight of the driving member is increased. As a result, the size and power consumption of the actuator for driving the correction lens group increase. For the above reasons, even if vignetting occurs during image blur correction, the outer diameter of the correction lens group is set to the standard state (without image state) is often determined.

FIG. 7 is an explanatory diagram of an image pickup optical system that performs image blur correction using a correction lens movement method. Each of FIGS. 7A, 7B, and 7C is an optical path diagram of the imaging optical system, and the passage range of the off-axis ray indicated by the image height HGT at the pupil position (aperture position) of the imaging optical system. showing. In FIG. 7, PO is the distance from the imaging plane IP to the exit pupil plane (exit pupil distance), SP is the iris diaphragm, and EPO is the exit pupil range. UR is the upper ray (hereinafter referred to as the upper line) of the ray bundle in FIG. 7, BR is the lower ray (hereinafter referred to as the lower line) of the ray bundle, and PR is the principal ray and the angle formed by the ray UR and the ray BR. is a ray that emerges onto the imaging plane IP at an angle that bisects . FIG. 7A shows a state in which symmetrical ray vignetting occurs in the vertical direction. FIG. 7B shows a state in which the upper line UR is greatly vignetted. FIG. 7(C) shows a state in which the underline BR is greatly vignetting.

FIGS. 8A to 8C show the division shape of the exit pupil incident on the focus detection pixel at the image height HGT corresponding to each state of FIGS. FIG. 3 is a diagram showing quantities; AR on the left side of each of FIGS. 8A to 8C represents the pupil shape of a ray bundle imaged at coordinate HGT at the pupil position (diaphragm position) of the imaging optical system in FIG. Similarly, SA and SB are ranges of light beams that can be received by the paired focus detection pixels (focus detection pixel pupil range). R1 and R2 indicate signal intensity waveforms of respective focus detection pixels, and the horizontal direction X corresponds to the vertical direction in FIG. L indicates the amount of image shift in the correlation signal of the signal intensity waveforms R1 and R2.

FIG. 8A shows the pupil shape of the ray bundle and the image shift amount L associated therewith when the ray vignetting in the X direction is symmetrical. Here, the signal intensity waveforms R1 and R2 in the pair of focus detection pixels have substantially similar shapes, and the respective image shift positions are also at equal distances from the pupil center position. Therefore, accurate correlation calculation can be performed, and accurate defocus information can be obtained using baseline length information equivalent to the pupil diameter defined by the pseudo aperture value.

FIG. 8B shows changes in the signal intensity of the correlation signal and the amount of image shift when the upper line of the ray bundle is greatly vignetted. Since the ray vignetting is greater in the range SB than in the range SA in FIG. 6A, the width of the correlation signal of the signal intensity waveform R2 in the X direction is short in the direction of the pupil center position. Therefore, the barycentric position from the pupil center in the signal intensity waveform R2 is shorter than the barycentric position of the signal intensity waveform R1. Therefore, the image shift amount L in FIG. 6B is smaller than the image shift amount L in FIG. 6A even in the same defocus state.

FIG. 8C shows changes in the correlation signal intensity and the amount of image shift when the underline of the bundle of rays is largely vignetted. Therefore, contrary to FIG. 8B, the signal intensity waveform R1 of the focus detection pixel is smaller than the signal intensity waveform R2 due to the effect of the ray vignetting. As a result, contrary to FIG. 8B, the position of the center of gravity of the signal intensity waveform R1 from the center of the pupil becomes shorter than that of the signal intensity waveform R2. Therefore, even in the same defocus state, the image shift amount is smaller than the image shift amount L in FIG. 8(A).

As described above, when performing image blur correction using the correction lens group movement method, the amount of image shift changes even though the focal state does not change due to eclipse caused by the movement of the correction lens group. put away.

Next, the phenomenon of the change in the amount of image shift that occurs during image shift correction by the image pickup device moving method using the image pickup device as the blur correction member will be described. First, referring to FIG. 9, a state will be described in which the image sensor 104 is moved to perform image blur correction when image blur occurs in the imaging optical system.

FIG. 9 is an explanatory diagram of an imaging apparatus that performs image blur correction by moving the imaging element. FIG. 9A shows the positional relationship between the image pickup optical system and the image pickup device when no image blur occurs. In FIG. 9A, AX is the optical axis of the imaging optical system, SP is the iris diaphragm, PO is the exit pupil position of the imaging optical system, and EP0 is the exit pupil range. IS indicates the image pickup device, and LS, CS, and RS indicate representative pixels at the left, center, and right positions around the image pickup device to simplify the explanation of the focus detection pixels on the image pickup device IS. FIG. 9B shows a state in which image blur correction is performed by moving the image sensor IS by a movement amount M when image blur of an angle ω occurs. As can be understood from FIG. 9, in the image blur correction state, the light ray angles from the exit pupil range EPO received by the representative pixels LS, CS, and RS change from those before the image blur correction.

FIG. 10 is an explanatory diagram of the light receiving state of the focus detection pixels at each image height in the state of FIG. 9A (before image blur correction). A focus detection pixel has a plurality of photoelectric conversion units for one microlens, as described with reference to FIGS. Here, for the sake of simplicity, the photoelectric conversion units in the focus detection pixel are divided in the X direction in FIG. The focus detection pixel array structure is such that the amount of image shift is detected from a pair of correlation signals generated from .

In FIG. 10, AX and EPO indicate the optical axis and exit pupil (exit pupil range) of the imaging optical system corresponding to FIG. 9A, respectively. SA and SB indicate division ranges (entrance pupil ranges) of the exit pupil EPO where the photoelectric conversion units A and B receive light, and LA and LB are perpendicular to the photoelectric conversion units A and B of the focus detection pixel LS. It is the incident chief ray. CA and CB are principal rays of the photoelectric conversion units A and B of the focus detection pixel CS. RA and RB are chief rays of the photoelectric conversion units A and B of the focus detection pixel RS. ML indicates a microlens of the imaging device 104 . When the exit pupil position is at a finite distance, the peripheral microlenses are displaced with respect to the photoelectric conversion section, thereby deflecting obliquely incident light rays. This prevents the light intensity received by the photoelectric conversion pixels A and B from decreasing due to the peripheral focus detection pixels having a larger angle from the entrance pupil ranges SA and SB than the central focus detection pixel. ing.

FIG. 11 is an explanatory diagram of the light receiving state of the focus detection pixels at each image height in the state of FIG. showing. Therefore, during image blur correction, the light beams incident on the photoelectric conversion units of the principal rays LA to RB incident on the photoelectric conversion units A and B of the focus detection pixels LS, CS, and RS are changed from the vertical angle. there is

FIG. 12 is a characteristic graph showing the relationship between the light receiving angle of the focus detection pixel and the output signal intensity after image blur correction. , the light receiving angle range is shown. As shown in FIG. 12, when the image sensor 104 is in the reference state, the LS and RS focus detection pixels output the signal intensity of the integrated value of the signal intensity in the light receiving angle range in the reference state.

On the other hand, when the image sensor moves as shown in FIG. 9B, the focus detection pixels LS and RS and the exit pupil position of the imaging optical system move in the correlation direction (X direction) perpendicular to the optical axis. The light-receiving angle range of the focus detection pixels for light emitted from the exit pupil changes. Specifically, the light beam reception angle range received by the LS and RS focus detection pixels when the image sensor 104 is moved by the movement amount M is indicated by a dashed line in FIG. 12 . As described above, when the image sensor 104 is moved to perform image blur correction, the range to be integrated by the pixel pupil intensity distribution characteristic changes, so the distance between the centers of gravity of the A image and the B image changes. The state in which the image shift amount changes due to this will be described below.

13A and 13B are diagrams showing the divided shape of the exit pupil incident on the focus detection pixels as the image sensor 104 moves and the amount of image shift in a pair of image shift signals. The change state of the image shift amount in the light receiving state is shown. The left diagrams of FIGS. 13A to 13C show the exit pupil range of the imaging optical system in which the focus detection pixels can receive light at the exit pupil position (exit pupil distance PO) in FIG. EP0 indicates the exit pupil range of the image pickup optical system, and is a range obtained from the F number of the image pickup optical system and the ray vignetting state. SA and SB are exit pupil division ranges in which the photoelectric conversion units A and B respectively receive light.

FIG. 13A shows a state in which the image pickup device, in which the principal rays are perpendicularly incident on the photoelectric conversion units A and B before image blur correction, is not moved. FIG. 13B shows a state in which the angle of the principal ray incident on the focus detection pixels changes in the positive direction of the X axis (to the right in the drawing) in states such as CS and RS in FIG. FIG. 13C shows a state in which the angle of the principal ray incident on the focus detection pixels changes in the negative direction of the X-axis in states like CS and RS in FIG. The right diagrams of FIGS. 13A, 13B, and 13C show signal intensities of the photoelectric conversion units A and B in the X direction. In the present embodiment, the individual signal intensities are described for one representative focus detection pixel at each image height portion of the image sensor 104 for the sake of simplicity of explanation. However, the pair of phase difference signals used for the correlation calculation (detection of the amount of image shift) is output from the focus detection pixel array corresponding to the image spread of the blurred image in the correlation direction (X direction in this embodiment) centering on the representative pixel. is scanning the signal to be

RA and RB in FIGS. 13A to 13C respectively indicate signal intensities scanned by the photoelectric conversion units A and B of the focus detection pixels. L indicates the image shift amount obtained by the correlation calculation. 13B and 13C have base line lengths different from those in FIG. 13A with respect to the image shift amount in FIG. This is because the signal intensity characteristics and non-linear characteristics depend on the light receiving angle. Specifically, the light-receiving angle range of the LS and RS pixels in the reference state of FIG. This is because the integrated value of the signal intensity at . 13B has a shorter (smaller) image shift amount than FIG. 13A, and FIG. 13C has a longer (larger) image shift amount than FIG. 13A.

As described above, although the defocus state does not change during focus detection, the movement of the image blur correction member causes a phenomenon in which the image shift amount changes during focus detection. Therefore, if the equations (A) and (B) are applied using the baseline length information stored in the imaging apparatus 100 in advance, the defocus amount cannot be calculated accurately. Therefore, a phenomenon occurs in which focus detection processing and focus driving must be performed many times in order to achieve an in-focus state (hereinafter referred to as multi-time focusing). The multi-time focusing will be described below.

FIG. 14 is a graph comparing defocus transition states when an error occurs in the base line length information by varying the amount of image blur and the position of the image blur correction member. In FIG. 14, the vertical axis represents the actual defocus amount, and the horizontal axis represents the number of times the focus is driven until the defocus state (hereinafter referred to as the "parting-out in-focus width") which is regarded as an in-focus state after focus detection is performed. there is From the above equation, when the base line length information obtained from the base line length information is longer than the optimum base line length information in the shake correction state, the defocus amount is detected to be smaller than the true defocus amount. . Even if the focus drive is performed based on the defocus amount information, there occurs a phenomenon that the focusing width cannot be reached. For this reason, as indicated by the dashed line in FIG. 14, the incomplete focus drive is performed many times to achieve an in-focus state, resulting in a slow focusing speed.

Conversely, if short baseline length information is used with respect to the optimum baseline length information, the detected defocus amount will be large, contrary to the above. Therefore, contrary to the above, the defocus amount is detected to be larger than the true defocus amount. Therefore, as indicated by dashed lines in FIGS. 14A, 14B, and 14C, the focus position of the focus drive amount jumps over the focused focus position. Then, focus detection is performed again at the skipped and stopped focus position, and a defocus amount with a sign opposite to the previous focus detection result is detected.

Since the short base length information is used here as well, a phenomenon occurs in which the focused position is skipped again, and such focus movement is repeated until the defocus amount falls within the cut-off in-focus width. When such focus driving occurs, the change in blurring of the subject image becomes unnatural and the focusing speed becomes low. The above is the state of reduction in the focusing speed due to the change in the base line length caused by the movement of the motion compensation member.

In order to reduce the number of times of focusing that occurs many times due to the above-mentioned causes, it is desirable to detect the position of the image blur correction member and correct the base line length information appropriately. However, correction of the base line length is very difficult, especially in an imaging apparatus with an interchangeable imaging optical system, because information such as the specifications of each imaging optical system, the imaging state at the time of focus detection, and the focus detection coordinates of the imaging element are used. computational load. In addition, there is a delay between the time when the calculation is performed and the result is reflected, and there is a possibility that the information will deviate from the true base line length information required for focus detection.

In order to solve the above problem with simple means, it is conceivable to fix the image blur correction member at a prescribed position until just before focus detection and operate it only while image recording is being performed. However, while the user is confirming the subject in the shooting standby state, it is desirable to perform image blur correction to make it easier to aim at the subject. Therefore, it is desirable for the user to reduce the sensory degradation of the blur-corrected image while waiting for shooting, and to prevent the reduction of the focusing speed by a simple means.

Next, it will be shown that the number of focus movements until focusing changes depending on the image blur amount of the subject and the amount of movement of the image blur correction member from the reference position during focus detection. FIG. 14A shows a defocus transition state in which the image blur is large during focus detection and the position of the image blur correction member has largely moved with respect to the reference position. FIG. 14B shows a defocus state up to an in-focus state when the image blur amount is the same as in FIG. Show history. FIG. 14(C) shows a defocus transition to an in-focus state in a state where the image blur correction member movement amount is the same as in FIG. 14(A) but the image blur amount is small during focus detection. Indicates status.

From the graph of FIG. 14(A), the state in which focusing occurs many times is a state in which the subject is greatly out of focus when focus detection is started, resulting in a large blurred image, and in which the image blur correction member has moved greatly. It is understood that Therefore, if the image blur correction member is close to the specified position as shown in FIG. 14B even in a large blur state, the change in the image shift amount caused by the image blur correction member as described above is reduced. Therefore, it is possible to reduce the number of times of focusing driving even if the predetermined base line length information is used. Also, even if the image blur correction member deviates from the specified position, if the focus position is close to the in-focus position as shown in FIG. is made. Therefore, if the influence information of the image shift amount change accompanying the movement of the image blur correction member is acquired in advance, the blurring state of the object is detected at the start of the focus detection, and the image blur correction member prevents the occurrence of focusing many times. can be calculated.

It is the focus accuracy change information obtaining means 107 explained with reference to FIG. By controlling the movement of the position of the image blur correction member using the control position information and then performing focus detection, it is possible to prevent a decrease in focusing speed. However, if the movement control of the position of the image blur correction member is performed abruptly, the position of the displayed object will suddenly change, so it is necessary to correct the position of the object that the user is aiming for, and this will lead to a deterioration in sensual quality. . Such subject position change and sensual problem raises a problem that perceptual influence increases as the sharpness of the subject increases as the defocus amount decreases. As a countermeasure, the amount of image blurring of the subject for which focus detection is performed is detected during focus detection to determine the amount of control of the image blur correction member. It is effective to prevent the reduction of the burning time.

Next, a specific method for obtaining the control position information of the image blur correction member in order to prevent a decrease in focusing speed while reducing the above-described perceptual problem will be described below with reference to examples. First, weighting is set in accordance with the factors related to the characteristics of the image blur correction member and the degree of influence associated with the correction movement of the image blur correction member. When the image blur correction member is of the correcting lens group movement type, weighting (1) is set according to the optical vignetting rate when the correcting lens group as shown in Table 1 performs the maximum movement. At the same time, the weighting (2) in the narrowed state of the iris diaphragm 102 shown in FIG. 1 is set, and the weighting factors of weighting (1) and weighting (2) are multiplied. As a result, a coefficient (5) is obtained in which a weighting is set for the change in the base line length in consideration of the effects of ray vignetting when the aperture is wide open and the relaxation of the ray vignetting rate due to narrowing down. In the present embodiment, weighting is applied to the imaging element image height ratio, which will be described later, in order to avoid complication.

On the other hand, when the image blur correction member is of the imaging element moving type, the distance between the light receiving pupil position of the imaging element and the exit pupil position of the imaging optical system shown in Table 2 expresses the degree of influence of the baseline length error. For this reason, the difference between the reciprocal values of (1') and (2') in Table 2 is taken as the influence of the baseline length error, and the absolute value is multiplied by an integer scaling factor to weight the baseline length error amount. to get the coefficient (5) set to .

Next, Table 3 shows weighted common items in the focus detection state of the imaging device, regardless of the type of image blur correction member. The weighting (6) of the image height ratio of the imaging element is weighting for the position where focus detection is performed on the imaging element, and the weighting increases toward the periphery of the imaging element. For example, when the correlation direction in the case of the focus detection pixel structure as shown in FIG. 2 is one horizontal direction (the X direction in FIG. 2), the horizontal distance You may make it divide by the absolute value range of (horizontal coordinate).

Next, the weighting (7) of the image blur amount is determined from the image shift amount obtained from the pair of correlation signals, and is set so that the larger the image shift amount, the larger the blur state, and the larger the weighting. Here, the pixel pitch width of the image sensor is used as an example of the unit indicating the magnitude of the image shift. In addition, in order to determine the blurring state more accurately, the subject contrast evaluation may be performed within the focus detection range and the result thereof may be taken into consideration.

(8) selects a weighting value depending on whether the image blur correction member is at a positive position or a negative position with respect to a prescribed neutral position during focus detection. The position of the image blur correction member may straddle the neutral position in time series, but this phenomenon is considered to be a state in which the position of the image blur correction member moves slightly with respect to the neutral position, and the operation of controlling the image blur correction member is performed. Focus detection and focus driving should be performed first. Weighting factors (6), (7), and (8) are selected as described above.

Next, a control value for the image blur correction member is calculated from the selected weighting factor. For this reason, a weighting normalization coefficient is acquired in advance. Table 4 shows the items for obtaining the weighted normalization coefficient, the maximum value (9) that the weighting (5) for the change in the baseline length can take, the maximum weighting value of the imaging device image height ratio (10), and the amount of image blur. The maximum value (11) of the weighting of is obtained. Next, using the respective weighting coefficients obtained above, the allowable maximum position of the image blur correction member for preventing a reduction in focusing speed is calculated with respect to the position of the image blur correction member detected during focus detection.

Table 5 shows items for calculating the image blur correction member control value. First, let (A) be the maximum amount of movement of the base image blur correction member. (B) is obtained by multiplying the weighting coefficients (5), (6), (7), and (8) with respect to the focus detection state and the change in the base line length due to the specifications of the imaging device. Then, for normalization of weighting, (9), (10), and (11) are multiplied to obtain (C), and (B) is divided by (C) to obtain (D). (E) is for considering the numerical sign in the calculation formula depending on whether the position of the image blur correction member at the time of focus detection is a plus position or a minus position. From (A), (D), and (E) obtained above, the permissible position of the image blur correction member that performs correction to prevent a decrease in focusing speed is derived from the following equation (1).

((A)-((A)x(D)x(E)))x(E) (1)
Equation (1) is a calculation structure that limits the amount of movement from the maximum movement position of the image blur correction member according to the degree of influence of change in base line length. If the image blur correction member during focus detection is farther than the position calculated by equation (1), correction is performed to the position obtained by equation (1), focus detection is performed again, and the result is defocused. Focus drive is performed by calculating the focus amount. On the other hand, if the image blur correction member during focus detection is not at a distance from the position calculated by the formula (1), the defocus amount may be calculated directly from the focus detection result and focus drive may be performed.

By performing the above calculation processing, it is possible to achieve an imaging apparatus capable of controlling the position of the image blur correction member according to the blur state and preventing the reduction of the focusing speed. In this embodiment, each weighting coefficient described above is obtained by selecting a preset value as a list method to reduce the calculation load, but each weighting may be held as a polynomial coefficient for interpolation calculation. .

Next, with reference to FIG. 15, an example of the flow of processing from focus position detection in the imaging apparatus 100 according to the present embodiment to focusing operation of the imaging optical system will be described. FIG. 15 is a flow chart showing the control method (focusing process of the imaging device 100) in this embodiment. Each step in FIG. 15 is executed by each unit of the imaging device 100 .

In this embodiment, first, in step S01, the user operates the shutter release switch to start the focusing operation of the imaging device 100. FIG. However, the focus detection operation can be started at the timing when the imaging device is powered on, and the following processing may be performed before the shutter release operation.

Subsequently, in performing focus detection, the imaging device 100 acquires a focus detection position in step S02. For the focus detection position, the distance coordinate from the center position of the effective pixel area in the image sensor 104 or the ratio to the outermost peripheral position may be used. When the focus detection position is determined in step S02, a pair of correlation signals for that area is extracted. Then, in step S03, the imaging device 100 performs a focus detection operation. Here, the image shift amount is converted from the obtained correlation amount.

Subsequently, in step S04, the imaging apparatus 100 acquires image blur amount information obtained by estimating the image blur amount of the subject in the area where focus detection was performed from the image shift amount. Subsequently, in step S05, the imaging apparatus 100 acquires image blur correction member position information during focus detection. Subsequently, in step S06, the imaging apparatus 100 determines whether or not the image blur amount and the image blur correction member position obtained in step S04 are larger than the correction necessary threshold. If the image blur amount and the image blur correction member position are smaller than the correction necessary threshold in step S06, the process proceeds to step S12. On the other hand, when the image blur amount and the image blur correction member position are larger than the correction necessary threshold, the imaging apparatus 100 proceeds to step S07 and acquires base line length change factor information (focusing accuracy change information). The base line length change factor information is information relating to factors that change the image shift amount as the image blur correction member moves. When the imaging apparatus 100 adopts the correction lens group moving method, the information is information on the state of ray vignetting caused by the movement of the correction lens group. On the other hand, when the image pickup apparatus 100 employs the image pickup element moving method, as described above, the light receiving pupil position of the image pickup element 104 and the light receiving pupil position of the image pickup element 104 related to the influence of changes in the signal intensity of the focus detection pixels due to the movement of the image pickup element 104. The difference distance amount from the imaging optical system exit pupil position is a factor.

Subsequently, in step S08, the imaging device 100 calculates the maximum allowable position of the image blur correction member. An example of this calculation will be described later. Subsequently, in step S09, the imaging apparatus 100 determines whether or not the allowable position (maximum allowable position) of the image blur correction member position acquired in step S08 is larger than the allowable position threshold. If the permissible position is greater than the permissible position threshold, the imaging apparatus 100 proceeds to step S10 and moves the image blur correction member into the permissible position. Note that the image blur correction member can be moved within the range of the allowable position calculated in step S08 from the neutral position of the image blur correction member.

After moving the image blur correction member, in step S11, the imaging device 100 performs the focus detection operation again. Based on the correlation (image deviation) information obtained by the focus detection operation in step S11, the imaging apparatus 100 acquires baseline length information corresponding to the setting state of the imaging optical system during focus detection. Subsequently, in step S12, the imaging apparatus 100 performs calculation regarding the defocus amount based on the baseline length information and the correlation amount, and the focus drive amount (focus drive amount) for bringing the remaining defocus state into the focused state. quantity information). Subsequently, in step S13, the imaging device 100 performs a focus driving operation using the obtained focus driving amount. After performing the focus driving operation, in step S14, the imaging apparatus 100 performs the focus detection operation again, and detects the defocus amount again from the correlation amount detected by the focus detection operation.

Subsequently, in step S15, it is determined whether or not the detected defocus amount is within the range (in-focus state) considered to be in-focus (in-focus determination is performed). If it is determined in step S15 that the focus state is not reached, the process returns to step S12. Then, the imaging apparatus 100 performs the focus driving amount calculation, the focus driving operation, and the focus detection operation to bring the in-focus state again, and performs the processing of steps S12 to S14 until the in-focus state is determined in step S15. repeat. On the other hand, if it is determined in step S15 that the camera is in focus, the imaging apparatus 100 stops the focus detection operation and shifts to an image capturing operation or the like when photographing a still image.

If it is determined in step S09 that the maximum permissible position of the image blur correction member calculated in step S08 is smaller than the permissible position threshold value, the process proceeds to step S12, and until the imaging apparatus 100 is in a focused state, step S12 is performed. The processing of to S14 is repeated. The flow from the focus detection of the present embodiment to the position control of the image blur correction member according to the image blurring state and the focusing has been described above.

Next, referring to FIG. 16, a processing method for an imaging apparatus in which focus detection pixels are capable of performing correlation calculations in both the X direction and the Y direction as described with reference to FIGS. 2 to 4 will be described. Here, in order to reduce the movement control amount of the image blur correction member, the correlation result in both the X and Y directions and the position of the image blur correction member are detected, and the correlation result in the direction in which the movement control of the image blur correction member becomes small. A method of performing focusing drive will be described.

FIG. 16 is a flow chart showing another control method in this embodiment. Each step in FIG. 16 is executed by each unit of the imaging device 100 . First, in steps S101 and S102, the imaging device 100 acquires the focus detection position determined by the user's shutter release operation, similarly to steps S01 and S02 in FIG. Subsequently, in step S103, the imaging apparatus 100 acquires the amount of movement (movement control amount) of the image blur correction member in the X and Y directions of the correlation. The amount of movement here corresponds to the amount of movement of the image blur correction member from the specified position in the uncorrected state.

Subsequently, in step S104, the imaging device 100 compares the amount of movement in the X direction and the amount of movement in the Y direction, and determines in which direction the amount of movement is smaller. The amount of comparison at this time may be compared in absolute value so as not to affect the positive direction and the negative direction of movement. However, if the degree of influence of the change in the amount of image shift differs depending on the direction, the amount of movement in the direction of movement may be weighted as focusing accuracy change information. If the movement amount of the image blur correction member in the X direction is smaller than the movement amount in the Y direction in step S104, the process proceeds to step S105, and the imaging apparatus 100 selects movement control of the image blur correction member in the X direction. On the other hand, when the amount of movement in the Y direction is smaller than the amount of movement in the X direction, the imaging apparatus 100 proceeds to step S106 and selects movement control of the image blur correction member in the Y direction.

Subsequently, in step S107, the imaging apparatus 100 performs the focus detection operation in the correlation direction selected in step S105 or step S105. is performed in the same manner as described above to bring the in-focus state. As described above, the control amount (movement control amount) of the image blur correction member is reduced, and it becomes possible to shorten the movement control time and suppress the movement change amount of the subject image during control.

According to the present embodiment, it is possible to suppress, with a simple process, reduction in focusing time caused by changes in focus detection due to movement of the image blur correction member when correcting image blur. The present embodiment is preferably applied to an image pickup apparatus including an image pickup device having phase difference detection type focus detection pixels. In addition to single-lens reflex cameras and compact digital cameras in which image blur is corrected by moving a lens group or an imaging element in an imaging optical system, the present embodiment can be applied to an imaging apparatus such as a video camera.

Table 6 shows an example of control calculation in a large blurring state and a small blurring state when the imaging apparatus 100 adopts the correction lens group movement correction method. Table 7 shows an example of control calculation in a large blurring state and a small blurring state when the imaging apparatus 100 adopts the imaging device movement correction method.

Thus, in this embodiment, the control device (imaging device 100) has focus detection means (correlation calculation means 116) and calculation means (focus driving amount calculation means 117). The control device also has correcting means (image blur correction member driving amount determining means 112, imaging element driving means 114) and acquiring means (focusing precision change information acquiring means 107). The focus detection means generates a first image signal obtained from the light flux passing through the first pupil region of the imaging optical system and a second image signal obtained from the light flux passing through the second pupil region of the imaging optical system. Focus detection is performed based on the correlation amount of (image shift amount is calculated). The calculation means calculates a focus drive amount for performing focus control based on the result of focus detection. The correction means performs image blur correction by moving the image blur correction member. The acquisition means acquires information (focusing accuracy change information) on changes in focusing accuracy due to movement of the image blur correction member. The correction means controls the movement of the image blur correction member using information about changes in focusing accuracy. The calculation means calculates a focus drive amount based on the result of focus detection after movement control of the image blur correction member.

Preferably, the image blur correction member is an imaging device (104). Information about changes in focusing accuracy includes entrance pupil position information of the imaging element (imaging element light receiving pupil information 108), exit pupil position information of the imaging optical system (imaging optical system exit pupil information 109), and pixels for focus detection in the imaging element. position information (focus detection range). Preferably, the image blur correction member is an image blur correction lens of the image pickup optical system, and the information about the change in focusing accuracy is pixel position information (focus detection range) for focus detection in the image sensor and an image blur correction lens in the image blur correction lens. ray vignetting information for blur correction.

Preferably, the information about the change in focusing accuracy includes image blur amount information of the object obtained based on the result of focus detection. Preferably, the correcting means does not perform the movement control based on the information when the movement amount of the image blur correction member movement control based on the information regarding the change in focusing accuracy does not exceed a predetermined movement amount (S06). .

Preferably, the correction means moves the image blur correction member with only the correlation direction in which the focus detection means performs focus detection as the movement control direction (S104 to S107). More preferably, the correction means changes the movement amount of the image blur correction member according to the movement control direction (S105, S106). More preferably, the focus detection means calculates a first correlation amount in the first direction and a second correlation amount in the second direction, and when the first correlation amount is smaller than the second correlation amount, Focus detection is performed using the first correlation amount. Then, the correction means moves the image blur correction member in the first direction, and then performs image blur correction (S107).

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

According to the present embodiment, a control device, an imaging device, and a control method capable of suppressing a decrease in focusing speed by reducing an error in the amount of focus driving during image blur correction with a simple configuration, and program can be provided.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist.

100 imaging device (control device)
107 focusing accuracy change information acquisition means (acquisition means)
112 image blur correction member drive amount determination means (correction means)
114 Imaging element drive means (correction means)
116 Correlation calculation means (focus detection means)
117 focus driving amount calculation means (calculation means)

Claims (12)

The amount of correlation between the first image signal obtained from the light flux that has passed through the first pupil region of the imaging optical system and the second image signal obtained from the light flux that has passed through the second pupil region of the imaging optical system focus detection means for performing focus detection based on
calculation means for calculating a focus drive amount for performing focus control based on the result of the focus detection;
correction means for correcting image blur by moving an image blur correction member;
acquisition means for acquiring information about changes in focusing accuracy due to the movement of the image blur correction member;
The correcting means controls the movement of the image blur correction member using the information,
the calculation means calculates the focus drive amount based on the result of the focus detection after movement control of the image blur correction member ;
The control device , wherein the information includes image blur amount information of a subject obtained based on the result of the focus detection . The image blur correction member is an imaging device,
2. A method according to claim 1, wherein said information includes entrance pupil position information of said imaging element, exit pupil position information of said imaging optical system, and pixel position information of said focus detection in said imaging element. controller. The image blur correction member is an image blur correction lens of the imaging optical system,
2. The control device according to claim 1, wherein the information includes pixel position information for the focus detection in the imaging device and light ray vignetting information for the image blur correction in the image blur correction lens. 2. The correction means does not perform the movement control based on the information when the amount of movement of the image blur correction member by the movement control based on the information does not exceed a predetermined movement amount. 4. The control device according to any one of items 1 to 3 . 5. The image blur correction member according to claim 1, wherein the correction means moves the image blur correction member only in the direction of correlation in which the focus detection is performed by the focus detection means as a movement control direction. Control device. 6. The control device according to claim 5 , wherein said correction means changes the movement amount of said image blur correction member according to said movement control direction. The amount of correlation between the first image signal obtained from the light flux that has passed through the first pupil region of the imaging optical system and the second image signal obtained from the light flux that has passed through the second pupil region of the imaging optical system focus detection means for performing focus detection based on
calculation means for calculating a focus drive amount for performing focus control based on the result of the focus detection;
correction means for correcting image blur by moving an image blur correction member;
acquisition means for acquiring information about changes in focusing accuracy due to the movement of the image blur correction member;
The correcting means controls the movement of the image blur correction member using the information,
The calculation means calculates the focus drive amount based on the result of the focus detection after movement control of the image blur correction member,
The control device, wherein the correction means does not perform the movement control based on the information when the movement amount of the image blur correction member by the movement control based on the information does not exceed a predetermined movement amount. an imaging device;
An imaging apparatus comprising: the control apparatus according to any one of claims 1 to 7 . 9. The imaging apparatus according to claim 8 , wherein said imaging device has focus detection pixels that output said first image signal and said second image signal. The amount of correlation between the first image signal obtained from the light flux that has passed through the first pupil region of the imaging optical system and the second image signal obtained from the light flux that has passed through the second pupil region of the imaging optical system a focus detection step for performing focus detection based on
a calculation step of calculating a focus drive amount for performing focus control based on the result of the focus detection;
a correction step of performing image blur correction by moving an image blur correction member;
an acquiring step of acquiring information about changes in focusing accuracy due to the movement of the image blur correction member;
In the correcting step, movement control of the image blur correction member is performed using the information,
in the calculating step, calculating the focus drive amount based on the result of the focus detection after movement control of the image blur correction member ;
The control method , wherein the information includes image blur amount information of a subject obtained based on the result of the focus detection . The amount of correlation between the first image signal obtained from the light flux that has passed through the first pupil region of the imaging optical system and the second image signal obtained from the light flux that has passed through the second pupil region of the imaging optical system a focus detection step for performing focus detection based on
a calculation step of calculating a focus drive amount for performing focus control based on the result of the focus detection;
a correction step of performing image blur correction by moving an image blur correction member;
an acquiring step of acquiring information about changes in focusing accuracy due to the movement of the image blur correction member;
In the correcting step, movement control of the image blur correction member is performed using the information,
in the calculating step, calculating the focus drive amount based on the result of the focus detection after movement control of the image blur correction member;
A control method, wherein in the correcting step, the movement control based on the information is not performed if the amount of movement of the image blur correction member by the movement control based on the information does not exceed a predetermined movement amount. A program causing a computer to execute the control method according to claim 10 or 11 .

Images