JP2019113600A - Imaging apparatus and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire a captured image having good image quality by notifying a change in image quality while exhibiting an image blur correction effect. An image pickup apparatus includes a correction lesbian 103 for image blur correction and a focus lens 104 for focus adjustment. The system control unit 119 calculates the runout correction amount corresponding to the movement amount of the correction lens 103 based on the runout detection signal by the runout detection unit 113. The image blur correction lens driving unit 116 moves the correction lens 103 according to the amount of image stabilization. The focus control unit 123 controls to move the focus lens 104 in conjunction with the drive of the correction lens 103. When the image quality of the image to be captured changes with the driving of the correction lens 103, the system control unit 119 controls to notify the user of the image deterioration range, and according to the user's operation instruction, the cut-out image is extracted by the image extraction. Generate data. [Selection diagram] Fig. 7

Description

  The present invention relates to the technology of image blurring correction processing of a captured image.

  As the magnification of the imaging device advances, the shake applied to the imaging device due to camera shake or the like becomes more noticeable in telephoto photography, and therefore, there is a demand for improvement in the performance of the image shake correction mechanism. The image shake correction mechanism detects camera shake and the like, and moves a shake correction lens (hereinafter, also simply referred to as a correction lens) and the like that constitute an imaging optical system in a direction substantially orthogonal to the optical axis. If the correction lens is moved to a large extent in order to improve the image blur correction performance, the amount of deviation from the optical axis increases, so the object contrast at the center of the captured image may be reduced and the optical performance may be reduced.

  In the contrast AF (Auto Focus) method, in the through image before the start of exposure, a position where the subject contrast is high in order to focus on a predetermined subject is calculated. The focus lens moves to the calculated position, and when the subject is in focus, the focus lens holds the position. When a shake occurs in the imaging device in a focused state in which the subject is in focus, the correction lens moves in accordance with the shake detection signal, and the shake is cancelled.

  For example, it is assumed that the object contrast at the center of the image is lowered because the correction lens is largely deviated from the optical axis of the imaging optical system, and the through image becomes an image in a blurred state. It is assumed that exposure to the imaging device starts and the focus lens is held at a fixed position during exposure. If a shake of the imaging device is detected during exposure, the correction lens is driven, so that the captured image becomes an exposed image in a state where the subject contrast is lowered. To solve this problem, when the drive amount of the correction unit is large, the drive unit of the correction unit is returned to a predetermined drive range where no image degradation occurs due to aberration before exposure, or the drive amount of the correction unit is There is also a method of restricting and further prohibiting exposure. Patent Document 1 discloses an auto-focusing apparatus having a correction limitation function that limits camera shake correction to prevent over-correction.

JP, 2009-145852, A

The device disclosed in Patent Document 1 makes it possible to reduce the influence of camera shake on focusing accuracy, but since the drive of the correction lens is limited, the camera shake correction effect may be reduced.
An object of the present invention is to make it possible to obtain a captured image with good image quality by notifying a change in image quality while exhibiting an image blur correction effect.

  An apparatus according to an embodiment of the present invention calculates an amount of correction for correcting an image blur from a detection signal of the shake detecting unit, and controls the correcting unit for correcting an image blur of an image captured by the imaging unit. When the control means, the focus adjustment control means for controlling the drive of the focus lens that performs focus adjustment in conjunction with the drive of the correction means, and the image quality of the image captured by the imaging means are changed by the drive of the correction means And notification control means for performing control to notify an image range in which the image quality has changed.

  According to the present invention, it is possible to obtain a captured image with good image quality by notifying the image quality change while exhibiting the image blur correction effect.

FIG. 3 is a cross-sectional view of the lens barrel at the time of retraction of the imaging device according to the embodiment of the present invention. FIG. 2 is a sectional view of a lens barrel at the time of shooting of the imaging device according to the embodiment of the present invention. FIG. 2 is an exploded perspective view of a lens barrel according to an embodiment of the present invention. FIG. 5 is a detailed view of a zoom drive unit of the imaging device according to the embodiment of the present invention. FIG. 1A is a front view and a cross-sectional view of a correction lens according to an embodiment of the present invention. It is a figure showing the focus drive mechanism part concerning the embodiment of the present invention. It is a block diagram showing an example of composition of an imaging device. It is a figure explaining the fall of the to-be-photographed object contrast by the drive of a correction lens. It is a figure which shows the correction amount of the focus lens corresponding to the movement amount of a correction lens. It is a figure which shows the relationship between the movement of a correction lens, and judgment of image quality fall. It is explanatory drawing of notification of an image quality degradation range, and an image clipping range. It is a figure explaining an image quality judging method. It is a flow chart explaining processing of an imaging device concerning a 1st embodiment of the present invention. It is a flowchart which shows the process following FIG. It is a flow chart explaining processing of an imaging device concerning a 2nd embodiment of the present invention. It is a flowchart which shows the process following FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the overall configuration of the zoom lens barrel is shown in FIGS. 1 to 3 with regard to the configuration of the apparatus common to each embodiment. FIG. 1 shows a zoom lens barrel in a collapsed state (hereinafter simply referred to as a lens barrel), and FIG. 2 shows a lens barrel in a stretched state. FIG. 3 is an exploded perspective view of the lens barrel. In the following, the object side is defined as the front side, and the side away from the optical axis of the imaging optical system is defined as the outer peripheral side, and the positional relationship of each part will be described.

  In the present embodiment, a lens barrel having a three-group lens configuration is exemplified. The first group unit includes a first group lens holding frame 11 for holding the first lens group 1 and a first group base plate 12 provided with a lens barrier member for holding the first group lens holding frame 11 and protecting the lenses. The second group unit includes a diaphragm unit 21 having a light amount adjusting member at the time of photographing, a second group lens holding frame 31 for holding the second lens group 2, and a second group base plate 32 having a shutter member not shown. The first unit, the aperture unit 21 and the second unit form a variable magnification optical system. The second group unit includes an image shake correction mechanism unit, and the second lens group 2 and the second group lens holding frame 31 move in a direction substantially orthogonal to the optical axis during shooting to prevent image shake due to camera shake or the like at the time of shooting. to correct. The third lens group 3 is a focus lens group for focusing on a subject, and is held by a third group lens holding frame 41.

  In the shooting standby state of FIG. 1, each lens group is in the storage state, and in the shooting state of FIG. 2, each lens group is in the state of being extended in the optical axis direction. The third lens group 3 and the imaging element 5 are attached to a sensor holder unit positioned closer to the rear end in the optical axis direction. The image sensor 5 is supported by the sensor holder 501 via a sensor plate 505. The optical filter 4 at the front of the imaging device 5 is disposed in a state of being sandwiched between the sensor holder 501 and a sensor rubber (not shown). As shown in the perspective view of FIG. 3, the lens barrel includes a fixed cam barrel 504 that constitutes a zoom mechanism. The fixed cam barrel 504 is screwed to the sensor holder unit.

  FIG. 3 shows the first group base plate 12, the diaphragm unit 21, the second group lens holding frame 31, the fixed cam barrel 504, the moving cam ring 503, the straight advance guide barrel 502, and the sensor holder 501. FIG. 4 shows the moving cam ring 503 and its drive mechanism. In the sensor holder 501, a zoom motor 601 and gear trains 603 to 606 are arranged. The gear 602 attached to the drive shaft of the zoom motor 601 is rotated by the drive force of the zoom motor 601, and the rotational force is transmitted to the moving cam ring 503 via the gear trains 603 to 606, and the lens barrel is an optical axis. Driven in the direction. The gear trains 603 to 606 are stepped gears coaxially having large diameter gears and small diameter gears having different numbers of teeth. The final gear 606 meshing with the gear portion 503e of the moving cam ring 503 is constituted by a large diameter gear portion and a small diameter gear portion long in the optical axis direction.

  Next, a cylindrical member and a zoom drive mechanism for moving each lens group in the optical axis direction will be described. As shown in FIGS. 1 and 2, a moving cam ring 503 is disposed on the outer peripheral side of each lens group. In the inner peripheral surface portion of the movable cam ring 503, cam grooves 503a, 503b, 503c (FIG. 3) having three different trajectories are formed. The follower pins 12a, 21a, 32a respectively formed on the outer circumferences of the first group base plate 12, the diaphragm unit 21 and the second group base plate 32 engage with and follow the cam grooves.

  Further, as shown in FIGS. 1 and 2, a rectilinear guide cylinder 502 is provided on the inner peripheral side of the moving cam ring 503, and regulates rotation when each lens group moves. The rectilinear guide cylinder 502 and the moving cam ring 503 are so-called bayonet coupled and move substantially integrally in the optical axis direction. The moving cam ring 503 is rotatable relative to the rectilinear guide cylinder 502. The straight guide cylinder 502 is provided with long grooves 502a, 502b and 502c (FIG. 3) extending in the optical axis direction. The first group base plate 12, the diaphragm unit 21 and the second group base plate 32 are linearly regulated along the optical axis direction by being restricted in rotation by the long grooves 502a, 502b and 502c.

  A cam groove 504 a and a rectilinear guide groove 504 b which is a linear groove are formed on the inner peripheral surface portion of the fixed cam barrel 504. As shown in FIG. 3, the follower pin 503d formed on the outer peripheral surface of the moving cam ring 503 engages with the cam groove 504a and follows. The guide groove 504 b is slidably fitted to the straight movement restricting portion 502 d of the straight movement guide cylinder 502. A gear portion 503 e formed on the outer peripheral surface of the moving cam ring 503 meshes with the final gear 606 of the gear trains 603 to 606. The driving force is transmitted from the final gear 606 to the gear portion 503e by the driving of the zoom motor 601, whereby the moving cam ring 503 rotates in the optical axis direction while engaging with and following the cam groove 504a of the fixed cam barrel 504. Moving.

  As shown in FIG. 4, the gear portion 503e of the moving cam ring 503 meshes with the small diameter gear which is a part of the final gear 606, and the large diameter gear is positioned rearward of the small diameter gear in the optical axis direction (image side) It meshes with the gear 605. The small diameter gear portion (long gear portion) of the final gear 606 is formed long in the optical axis direction to correspond to the movement of the moving cam ring 503 in the optical axis direction in accordance with the amount of extension of the moving cam ring 503. The rectilinear guide cylinder 502 moves integrally with the moving cam ring 503 in the optical axis direction. The rectilinear guide cylinder 502 includes a rectilinear guide portion 502d on the outer peripheral portion on the rear end side (FIG. 3). The rotation of the rectilinear guide portion 502d is regulated by being slidably fitted in the rectilinear guide groove 504b of the fixed cam barrel 504, so that the rectilinear guide barrel 502 performs only rectilinear movement in the optical axis direction.

  In the present embodiment, as the moving cam ring 503 rotates, the first unit, the aperture unit 21 and the second unit following the moving cam ring 503 move in the optical axis direction while being rectilinearly restricted. Since the fixed cam barrel 504 is integrally formed with the sensor holder 501 by a screw, it does not move in the optical axis direction or in the rotational direction.

  Next, with reference to FIG. 5, the image blur correction device will be described. The anti-shake apparatus comprises a second unit and its drive unit. FIG. 5A is a front view of the second group unit viewed from the subject side. FIG. 5 (B) is a cross-sectional view of the case where the second group unit is cut at the lens center, and the cutting position is shown in FIG. 5 (A).

  A lens driving unit of a second group unit is provided on the outer peripheral side of the second group base plate 32. The second group lens 2 functions as a correction lens (so-called shift lens). The lens driving unit includes a magnet 37 and a coil 38, and moves the second lens group holding frame 31 in a direction orthogonal to the optical axis. A shutter driving unit (not shown) for driving the shutter mechanism is provided on the outer peripheral side of the second lens group 2 in the second lens group base plate 32. On the image surface side (rear side) of the second group base plate 32, an ND driving unit (not shown) for driving an ND (Neutral Density) filter is provided.

  The second group lens holding frame 31 and the second group base plate 32 are connected in the optical axis direction by two tension springs (not shown). Due to the biasing force of the two tension springs, the second lens group holding frame 31 is biased against the second group base plate 32 with the plurality of balls 35 interposed therebetween in the optical axis direction. The rolling of the ball 35 moves the second lens group holding frame 31 in the direction orthogonal to the optical axis.

  A hall element holding portion 34 is disposed in front of the second group base plate 32. The shutter FPC (flexible wiring member) 33 is drawn on the hall element holding portion 34 in a state of being connected to the lens driving portion, the shutter driving portion, and the ND driving portion. It is drawn out to the image plane side along the drawing surface. Hall elements 36 for detecting the positions of the second group lens 2 and the second group lens holding frame 31 are mounted on the shutter FPC 33 at two positions separated by 90 ° in the circumferential direction. Each Hall element 36 is connected to a lens barrel FPC (not shown) via the shutter FPC 33. The shutter FPC 33 is fixed to the Hall element holding portion 34, and the Hall element holding portion 34 is engaged with the second group base plate 32 by snap fit connection with the second group lens 2 interposed therebetween.

  The second lens group holding frame 31 is provided with a magnet 37 which is magnetized so as to sandwich the Hall element 36 between the N pole and the S pole when viewed from the optical axis direction. The two Hall elements 36 detect the magnetic field generated by the magnet 37 and output a detection signal to the control unit in the camera body. When the second lens group holding frame 31 moves in a plane orthogonal to the optical axis, the magnetic field passing through the Hall element 36 changes and the output of the Hall element 36 changes, so that the position of the second group lens holding frame 31 is detected. Can.

  The coil 38 is disposed at a position facing the magnet 37 on the image plane side in the optical axis direction, and is attached to the second group base plate 32. The coil 38 is connected to the lens barrel FPC via the shutter FPC 33, and receives power supply from the power supply unit of the camera body. The energization of the coil 38 generates an electromagnetic force to drive the second lens group holding frame 31.

  The focus drive mechanism section will be described with reference to FIGS. 3 and 6. The focus drive mechanism is attached to the sensor holder unit. FIG. 6A is an exploded perspective view of the focus drive mechanism, and FIG. 6B is a front view showing the main part of the focus drive mechanism. The third lens group 3 which is a focus lens group is moved in the optical axis direction by a drive unit using a lead screw.

  The third lens group holding frame 41 is supported by the sensor holder 501 so as to be linearly movable in the optical axis direction. A main guide shaft 42 (FIG. 6) extending in parallel with the photographing optical axis is press-fitted and fixed in a hole of the sensor holder 501. Similarly, the sub-guide shaft 43 for rotation restriction is press-fit and fixed to the hole of the sensor holder 501.

  The focus drive motor 44 (FIG. 6) is fixed to the sensor holder 501 by fastening with a screw. In the sleeve 41a provided in the third group lens holding frame 41, sleeve holes that engage with the main guide shaft 42 are formed at both ends, and a sleeve opening is formed in the center. Further, a U-shaped groove 41 b engaged with the sub guide shaft 43 is formed in the third group lens holding frame 41. Further, in the third group lens holding frame 41, a support hole 41c for supporting the rack 45 is provided in the vicinity of the sleeve 41a.

  The lead screw 44 a is integrally formed with the output shaft of the focus drive motor 44. The rack 45 includes meshing teeth 45a meshing with the lead screw 44a and biasing teeth 45b opposed thereto. Further, the rack 45 is formed with a support shaft that engages with the support hole of the third group lens holding frame 41. The biasing tooth 45 b is pressed by the arm of the torsion coil spring 46 in the direction in which it engages with the lead screw 44 a. The arm of the torsion coil spring 46 is hooked on the back of the rack 45. As a result, the lead screw 44a is sandwiched between the urging teeth 45b and the meshing teeth 45a. That is, the biasing tooth 45b and the meshing tooth 45a are always in a state of meshing with the lead screw 44a.

  Further, the torsion coil spring 46 biases the rack 45 in the direction toward the end surface of the third lens group holding frame 41 in the optical axis direction, and prevents rattling of the rack 45 and the third lens group holding frame 41. Therefore, the lens drive is performed with high precision and stably in the optical axis direction. In the focus drive mechanism portion, when the lead screw 44a is rotated by the focus drive motor 44, the third group lens holding frame 41 moves back and forth in the optical axis direction due to the screwing relationship between the rack 45 and the lead screw 44a, and the focus adjustment operation is performed. It will be.

  The internal configuration of the imaging apparatus will be described with reference to FIG. FIG. 7 is a block diagram showing the configuration of a digital camera 100 as an example of an imaging device. The lens barrel 101 includes various optical members. The zoom lens 102 optically changes the angle of view by adjusting the focal length. The correction lens 103 performs an image blur correction operation by decentering the optical axis. The focus lens 104 performs a focusing operation. The aperture and shutter 105 are used for exposure control to adjust the amount of light.

  The imaging unit includes an imaging element 106 using a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor). The imaging element 106 receives light passing through the lens barrel 101, and outputs an electrical signal by photoelectric conversion. The electrical signal is input to the image processing circuit 107, subjected to pixel interpolation processing, color conversion processing, and the like, and then stored in the internal memory 108 as image data. The display unit 109 acquires image data after shooting, shooting information, and the like, and displays them on the screen. The image processing circuit 107, the internal memory 108, and the display unit 109 are connected to the system control unit 119, and perform processing in accordance with a control instruction from the system control unit 119.

  The compression / decompression processing unit 110 acquires data stored in the internal memory 108, and performs compression / decompression processing according to a predetermined image format. The storage unit 111 stores various data such as parameters. The compression / decompression processing unit 110 and the storage unit 111 are connected to the system control unit 119, and perform processing in accordance with a control command from the system control unit 119. The operation unit 112 is a user interface unit for performing various menu operations, mode switching operations, and the like. For example, the user can use the operation unit 112 to switch between still images and moving images, and switch between manual focus and auto focus. The operation signal of the operation unit 112 is output to the system control unit 119. The shake detection unit 113 includes an angular velocity sensor or the like, detects a shake applied to the imaging apparatus, and outputs a shake detection signal to the system control unit 119.

  The diaphragm shutter drive unit 114, the focus lens drive unit 115, the image blur correction lens drive unit 116, and the zoom lens drive unit 118 perform drive that each unit takes charge of in accordance with a control command from the system control unit 119. The aperture shutter drive unit 114 drives the aperture and the shutter 105, and the focus lens drive unit 115 drives the focus lens 104. The image blur correction lens drive unit 116 drives the correction lens 103. The position detection unit 117 obtains the current position of the correction lens 103, and outputs a position detection signal to the system control unit 119. The zoom lens drive unit 118 drives the zoom lens 102.

  The system control unit 119 includes a CPU (central processing unit), executes various control programs stored in the internal memory 108 according to user operation, performs AE (automatic exposure) control, AF (auto focus) control, Image blur correction control, zoom control, etc. are performed. In FIG. 7, the function of the system control unit 119 is illustrated as a block element. The luminance signal calculation unit 121 calculates the luminance signal value of the subject based on the electrical signal output from the imaging element 106. The exposure control unit 120 calculates an exposure control value (aperture value and shutter speed) based on the luminance signal value calculated by the luminance signal calculation unit 121, and outputs the calculation result to the diaphragm shutter drive unit 114. The evaluation value calculator 122 extracts a specific frequency component from the luminance signal by the luminance signal calculator 121 and calculates an AF evaluation value. In addition, the evaluation value calculation unit 122 acquires position information and position correction information of the focus lens from the position correction unit 126 described later.

  The focus control unit 123 outputs a control signal to the focus lens drive unit 115 to control the drive direction and drive amount of the focus lens 104. The scan control unit 124 instructs the focus control unit 123 to drive the predetermined range, and calculates the contrast by referring to the calculation result (evaluation value) of the evaluation value calculation unit 122 at the predetermined position of the focus lens 104. . The AF control is performed with the focus lens position where the contrast is the highest as the in-focus position.

  The image shake correction control unit 125 calculates the correction direction for canceling the shake and the correction amount based on the detection information of the shake detection unit 113. The image blur correction control unit 125 acquires the current position of the correction lens 103 from the position detection unit 117, and performs image blur correction control by driving the correction lens 103. The position correction unit 126 corrects the position of the focus lens 104 according to the current position of the correction lens 103 acquired via the image shake correction control unit 125. The zoom control unit 127 calculates the drive direction and the drive amount of the zoom lens 102 in accordance with the zoom operation instruction from the operation unit 112, and performs drive control of the zoom lens 102.

  The operation unit 112 includes a release button in which the first switch (SW1) and the second switch (SW2) are sequentially turned on according to the amount of pressing. When the user half-presses the release button, the first switch SW1 is turned on. At this time, the exposure control unit 120 calculates an exposure control value (aperture value and shutter speed) based on the luminance information from the luminance signal calculation unit 121, and notifies the diaphragm shutter drive unit 114 of the calculation result. Thus, automatic exposure control is performed. The evaluation value calculation unit 122 calculates the AF evaluation value after the specific frequency component is extracted from the luminance signal by the luminance signal calculation unit 121. When the user further operates the release button and pushes it all the way, the second switch SW2 is turned on. The exposure control unit 120 performs exposure control based on the determined aperture value and shutter speed, and the captured image data acquired by the imaging element 106 is stored in the storage unit 111.

  The user can display a so-called live view image acquired by the imaging device 106 in a state where the release button is not pressed. At this time, the system control unit 119 preliminarily determines the aperture value and the shutter speed based on the brightness information and the program diagram relating to the video signal at predetermined intervals in preparation for exposure at the time of still image shooting.

  Here, with reference to FIG. 8, a phenomenon that may occur when the correction lens is largely deviated from the optical axis, that is, an object focus shift will be described. FIGS. 8A and 8B are graphs showing the relationship between the focus lens position for a predetermined subject and the fluctuation of the contrast evaluation value of the subject. The X axis, which is the horizontal axis, represents the focus lens position, and the Y axis, which is the vertical axis, represents the contrast evaluation value of the subject. 8C and 8D are schematic views showing the zoom lens 102, the correction lens 103, the focus lens 104, and the imaging device 106, and FIG. 8C corresponds to FIG. 8A, and FIG. D) corresponds to FIG. 8 (B). As shown in FIGS. 8A and 8B, the contrast evaluation value of the subject changes depending on the position of the focus lens 104, and a change in mountain shape occurs due to the difference in height of the contrast. The top of the graph curve is the position where the contrast evaluation value is maximum, and when the focus lens 104 is at this position, the object is in focus.

  FIGS. 8A and 8C show the case where the correction lens 103 is positioned on the same optical axis as the other lens units. When the correction lens 103 is on the optical axis, as shown in FIG. 8A, when the position of the focus lens 104 is X1, the contrast evaluation value becomes the maximum value Y1. FIGS. 8B and 8D show the case where the correction lens 103 is at a position deviated from the optical axis. When the correction lens 103 is driven and deviates from the center of the optical axis as shown in FIG. 8D from the state of FIG. 8C, a graph of a mountain shape showing a contrast evaluation value as shown in FIG. 8B. The curve shifts to the right. That is, the position of the focus lens 104 at which the contrast evaluation value becomes maximum shifts from X1 to X2.

  It is assumed that the focus lens 104 moves to the position X1 when the correction lens 103 is on the optical axis, stops at this position, and the subject is in focus. Thereafter, when the correction lens 103 is moved, the graph curve indicating the contrast evaluation value is shifted as shown in FIG. 8 (B). At this time, since the contrast evaluation value falls from Y1 to Y2, if it is assumed that photographing is started at this time, the photographing operation is performed in a state where the contrast evaluation value is low. Furthermore, when the camera shake by the photographer is not constant and changes from moment to moment, the movement of the correction lens 103 changes with this change. That is, the movement of the correction lens 103 is not constant, and the contrast evaluation value of the subject always changes.

  The operation of the correction lens and the focus lens before and after shooting will be described with reference to FIG. FIG. 9 is a graph schematically showing the relationship between the movement amount of the correction lens 103 and the correction amount of the focus lens position. The vertical axis represents the amount of movement of the correction lens 103, that is, the displacement from the optical axis. The horizontal axis represents the correction amount of the focus lens 104 to be corrected when the correction lens 103 is driven, and the position correction unit 126 controls the position correction. When the position of the correction lens 103 is 0 degree, that is, on the optical axis, it is expressed as Mov0. When the position of the correction lens is Mov0, the correction amount of the focus lens position is Comp0. As a specific numerical value, Mov0 is 0 degrees, and Comp0 is zero.

  On the other hand, when the position of the correction lens 103 is farthest from the optical axis, it is expressed as Mov5. When the position of the correction lens 103 is Mov5, the correction amount of the focus lens position is Comp5. Correction amounts respectively corresponding to Mov1 to Mov4 between the positions Mov0 and Mov5 are Comp1 to Comp4. The correction amount of the focus lens position corresponding to the movement amount of the correction lens 103 is stored in advance in the internal memory 108 as reference table data, and is referred to by the position correction unit 126. Therefore, at the time of shooting, the focus lens 104 moves in accordance with the correction amount of the focus lens position according to the position of the correction lens 103 corresponding to the camera shake amount of the photographer.

  The respective values of Mov1 to 5 and Comp1 to 5 change depending on the characteristics of the imaging optical system. In the example of FIG. 9, although the relationship between the correction lens position and the correction amount of the focus lens position is expressed by a linear expression, it is not necessarily a linear relation, and is represented by a curve expression by the characteristics of the imaging optical system. There is also.

  Next, a description will be given of notification control to the user performed when the image quality is deteriorated due to the change of MTF (Modulation Transfer Function) of the image central portion and the peripheral portion by driving the correction lens in the imaging optical system. FIG. 10 is a diagram showing changes in MTF at the central part of the photographic screen and at four peripheral points when the correction lens 103 is positioned at the center of the optical axis and when the correction lens 103 is moved from the center of the optical axis. The illustrated MTF curve is an example, and changes according to the characteristics of the imaging optical system.

  FIG. 10A is a diagram showing the positions of the central portion and four peripheral portions with respect to the photographing screen. The central part of the shooting screen is represented by 0ch, and the peripheral part is represented by 1ch, 2ch, 3ch and 4ch in the clockwise direction from the upper right. FIG. 10B is a schematic view of an imaging optical system showing how the correction lens 103 is moved in the Y direction from the center of the optical axis. When it is detected that a shake is added to the imaging apparatus due to a shake of the operator or the like, the correction lens 103 is displaced in the Y direction of FIG.

  FIG. 10C shows MTF values at the central portion and four peripheral portions when the correction lens 103 is positioned at the center of the optical axis. FIG. 10D is a diagram showing MTF values at the central portion and four peripheral portions when the correction lens 103 is most separated from the optical axis center. In FIGS. 10C and 10D, the vertical axis represents the MTF value, and the horizontal axis represents the focus lens position, and shows how the MTF value of each channel changes depending on the position of the focus lens.

  The solid graph lines shown in FIGS. 10C and 10D represent MTF values in the horizontal direction (X direction) of the subject, and the dashed graph lines represent the MTF values in the vertical direction (Y direction) of the subject. As can be seen from FIG. 10C, the MTF curves in the horizontal direction and the vertical direction of the central portion 0ch and the four peripheral portions 1 to 4 become maximum values at substantially the same focus lens position F1. The system control unit 119 according to the present embodiment performs AF control so that the MTF value of the central 0 channel becomes the maximum value. In other words, the AF control moves the focus lens 104 to the position F1 at which the MTF value of the center 0 channel becomes maximum. At this time, since the positions at which the MTF values of the four peripheral portions 1 to 4 become maximum are substantially the same position F1, good image quality with high contrast can be obtained over the entire photographing screen.

  In FIG. 10D, the correction lens 103 is largely moved from the center of the optical axis by the image shake correction operation, and the MTF value changes. In the central portion 0ch of the screen, the maximum value of the MTF value is entirely lowered, and the peak position of the MTF value in the horizontal direction is shifted to the right in FIG. 10 (D). Further, with regard to the peripheral four places 1 to 4ch, the peak positions of the MTF values in the horizontal direction and the vertical direction of the 1ch and 4ch are both largely deviated to the right in FIG. 10 (D). In particular, the peak position of the MTF value in the horizontal direction is shifted so much that it can not be confirmed from this figure. In addition, in 2ch and 3ch, the maximum value of the MTF value is generally lowered similarly to 0ch, and the maximum values in the horizontal direction and the vertical direction are both shifted little by little to the right. It can be seen that the focus lens position at which the MTF value is maximum is deviated in the horizontal direction and the vertical direction in all of the central portion 0ch and the four peripheral portions 1 to 4ch. In the present embodiment, the change in the MTF curve when the correction lens 103 moves in the Y direction will be described. However, when the correction lens 103 moves in the X direction, or moves in the X direction and the Y direction, The degree of change of the MTF curve of each ch is different.

  As described in FIG. 9, the position of the focus lens 104 is changed according to the amount of movement (correction amount) of the correction lens 103. In FIG. 10D, the focus lens 104 moves from a position F1 indicated by a two-dot chain line to a position F2 indicated by a solid line. The focus lens 104 is moved to a position where the horizontal and vertical MTF values of the central portion 0ch are balanced. The image quality of the central 0 channel is not as high as when the correction lens 103 is located at the center of the optical axis, but a high image quality with high contrast can be obtained.

  The MTF curves of the peripheral portions 1 to 4 when the focus lens 104 moves to the position F2 will be described. With regard to 2ch and 3ch, the position correction operation of the focus lens 104 changes the MTF value in the direction to improve in both the horizontal direction and the vertical direction. In the vertical direction, the position F2 is a position at which the MTF value becomes the maximum value, as can be seen from the broken curve curve. Although the MTF value in the horizontal direction is slightly deviated from the maximum value, good image quality with high contrast can be obtained.

  On the other hand, with regard to 1ch and 4ch, the position correction operation of the focus lens 104 changes the MTF value in the vertical direction to the improving direction. However, since the MTF curve in the horizontal direction is largely changed by the driving of the correction lens 103, it falls below the set reference and the desired image quality can not be obtained. In this case, processing is performed to notify the user of the image quality deterioration caused by the driving of the correction lens 103.

  An example of notification to the user will be described with reference to FIG. FIGS. 11A and 11B are schematic views of an imaging optical system similar to FIG. 10B. FIG. 11A shows how the correction lens 103 moves in the + Y direction, and FIG. 11B shows how the correction lens 103 moves in the −Y direction. FIGS. 11C and 11D are diagrams showing how a through image before the start of exposure is displayed on the screen of the display unit 109. FIG. FIG. 11C shows a display example at the correction lens position shown in FIG. 11A, and FIG. 11D shows a display example at the correction lens position shown in FIG. FIG. 11E is a diagram showing how the range of image quality degradation is notified on the confirmation screen after the end of shooting. FIG. 11F is a view showing a state in which a cutout range of an image is notified after shooting.

  When camera shake or the like is detected in the display state of the through image before exposure, and the correction lens 103 moves in the + Y direction as shown in FIG. 11A, the position correction of the focus lens 104 is interlocked with the movement of the correction lens 103. To be done. As described in FIG. 10, when the amount of movement of the correction lens 103 is large, it is difficult to improve the MTF value of the peripheral portion even when the position of the focus lens 104 is corrected. If exposure is started as it is, the system control unit 119 determines that the upper corner of the screen may not reach the standard image quality. As shown in FIG. 11C, the system control unit 119 performs processing for applying a gray mask to the image area in the + Y direction, that is, a predetermined area 1100 at the top of the screen. Further, as shown in FIG. 11B, the correction lens 103 moves in the −Y direction, and the system control unit 119 determines that the lower corner of the screen may not reach the reference image quality. In this case, as shown in FIG. 11D, the system control unit 119 performs processing of applying a gray mask to the image area in the -Y direction, that is, the predetermined area 1101 at the lower part of the screen. The criteria for determining whether to apply a gray mask and the method for determining the gray mask range will be described later.

  In the display state of the through image before exposure, the user can recognize camera shake by observing that a predetermined area on the display screen is covered with a gray mask, and can correct the photographing operation. When the exposure operation is performed, as in the case before exposure, a process of applying a gray mask to a predetermined area of the screen is performed as shown in FIGS. 11C and 11D according to the camera shake amount, so the user recognizes the camera shake. can do.

  FIG. 11E shows gray masks for upper and lower peripheral areas 1102 and 1103 where it is determined that the MTF value of the peripheral image area is low due to the movement of the correction lens 103 during exposure in the confirmation image after exposure. It shows how it was applied. The user sees the gray mask display and can immediately recognize that the image quality has been partially degraded due to camera shake. Thereafter, in order to provide a high quality image with little degradation in image quality, the system control unit 119 executes processing to have the user select whether or not to generate a cutout image excluding a portion in which the image quality is degraded. At this time, processing for clearly indicating the clipping range in FIG. 11F is executed so that the clipping range of the image can be known. For example, the system control unit 119 performs a process of displaying the clipping range (see the dashed rectangular frame 1104) on the screen of the display unit 109. By displaying the clipping range in the area excluding the area in which the image quality is degraded, the user can confirm the composition and the like of the subject. Also, the user can determine whether a clipped image is required. When the user determines that the cut-out image is necessary, and an operation of selecting the cut-out image, for example, an instruction operation with a finger on the touch panel is performed, the system control unit 119 generates data of the selected cut-out image. Execute the process

  As described above, the user can recognize occurrence of camera shake or the like by displaying the image area where the image quality deterioration occurs with respect to the through image before exposure and the image after capturing. Furthermore, by extracting image data in an image range having a good image quality and presenting the cutout image to the user, it is possible to prevent a failure in imaging.

  11C to 11E illustrate the process of covering the image quality reduction area caused by driving the correction lens 103 with a gray mask, but the method of notifying the user is not limited, and the image quality reduction area is arbitrary Can be displayed. Also, in the example of FIG. 11F, the data of the cutout image is generated with the same aspect ratio as the original image at the time of shooting, but the extraction processing of the image area may be performed with an aspect ratio different from the original image. . Besides the method of selectively acquiring the original image and the cutout image, there is a method of acquiring only the cutout image or acquiring the original image and the cutout image.

  The image quality determination method in the present embodiment will be described with reference to FIG. In the image quality determination, it is not determined by confirming the actual image, but determined by the position of the correction lens 103. FIG. 12 is a graph showing an example of the movement of the correction lens 103.

  FIG. 12A is a view showing an example of the movement of the correction lens in the display state of the through image before exposure. The vertical axis represents the position of the correction lens 103, and the horizontal axis is a time axis. The correction lens 103 moves to correct an image blur due to a shake of the operator or the like, but the shake correction amount differs according to the degree of the shake or the like. Z1 indicates the movable range of the correction lens 103, and Z2 indicates the image quality allowable range when the correction lens 103 moves. The image quality allowable range is a range in which the image quality is not affected even if the correction lens 103 moves (range within the threshold).

  In the display state of the through image before exposure, the correction lens 103 is moved to a position exceeding the image quality allowable range Z2, and the position detection unit 117 detects the current position of the correction lens 103. At this time, the user can recognize camera shake or the like by performing the display of FIG. 11 on the screen of the display unit 109 or the warning or alarm. For example, when the position of the correction lens 103 exceeds the allowable image quality range Z2 (see the ranges 1201 and 1202), a warning or notification process is executed each time.

  FIG. 12B illustrates the movement of the correction lens 103 during exposure, and the settings of the vertical axis and the horizontal axis are the same as FIG. 12A. If the correction lens 103 moves to a position beyond the image quality allowable range Z2 during exposure as well as before exposure, the user can recognize occurrence of camera shake or the like by a warning or notification. However, in this case, even if a warning or the like is issued, it has already been exposed. Therefore, the system control unit 119 calculates the image quality reduction range from the exposure time and the amount by which the position of the correction lens 103 exceeds the allowable range Z2 as shown by the shaded areas 1203 and 1204 in FIG. A process of displaying the image quality degradation range on the screen after shooting is executed. Note that the image quality allowable range Z2 shown in FIG. 12 is an example, and the image quality allowable range may be narrowed or expanded as necessary.

First Embodiment
Processing of the imaging device according to the first embodiment will be described with reference to FIGS. 13 and 14. FIG. 13 and FIG. 14 are flowcharts for explaining notification processing of the image quality deterioration range and clipping processing of a captured image according to the movement amount of the correction lens. Notification control to the user and image extraction processing described below are performed under the control of the system control unit 119.

  When the power of the imaging apparatus is turned on (S301), the shake detection unit 113 detects a shake of the imaging apparatus. The image shake correction control unit 125 calculates a shake correction amount of the correction lens 103 with respect to the detected shake (S302). The system control unit 119 starts the image blur correction control according to the shake correction amount, and the image blur correction lens driving unit 116 drives the correction lens 103 (S303). Then, the system control unit 119 starts correction of the focus lens position and movement control according to the movement amount of the correction lens 103. The position correction unit 126 acquires the movement amount corresponding to the correction amount of the correction lens 103 from the image shake correction control unit 125, calculates the correction amount of the focus lens position, and outputs the correction amount to the scan control unit 124. The focus control unit 123 controls the focus lens drive unit 115 to move the focus lens 104 to the position corrected according to the control command from the scan control unit 124. Thereby, the focus lens 104 moves on the optical axis according to the drive target value corresponding to the in-focus position (S304).

  Subsequently, the system control unit 119 determines whether the position of the correction lens 103 is a position within a predetermined range with respect to the optical axis center (S305). When the position of the correction lens 103 is within a predetermined range with respect to the optical axis center, that is, when the calculation result of the shake correction amount is equal to or less than the predetermined amount, the process proceeds to the process of S308. If the calculation result of the shake correction amount is larger than the predetermined amount, the process proceeds to step S306. The predetermined amount is a threshold set in advance. The determination may be made by comparing the amount of movement of the correction lens 103 with a predetermined threshold. In step S306, the system control unit 119 executes processing for calculating the image quality deterioration range in the peripheral portion of the screen. Next, processing for notifying the user of the image quality reduction range calculated in S306 is executed (S307). Thereafter, the process proceeds to S308.

  In step S308, the system control unit 119 determines whether the second switch SW2 is turned on by the operation of the release button. If it is determined that the second switch SW2 is not on, the process returns to S302 in the live view image display state to continue the process. On the other hand, when it is determined that the second switch SW2 is turned on, the process proceeds to S309 in FIG.

  In step S309, the system control unit 119 starts a shooting operation, and the exposure control unit 120 starts exposure. Even during exposure, the shake detection unit 113 detects shake of the imaging device, and the image shake correction control unit 125 calculates a shake correction amount of the correction lens 103 with respect to the detected shake (S310). The system control unit 119 performs image shake correction control, and the image shake correction lens drive unit 116 drives the correction lens 103 according to the control signal from the image shake correction control unit 125 (S311). When the exposure is started, the system control unit 119 determines that the image capturing state is set, and proceeds to S312 to perform focus adjustment control. That is, the focus control unit 123 controls the focus lens drive unit 115 according to the position correction amount corresponding to the movement amount of the correction lens 103. By moving the focus lens 104 in conjunction with the image blur correction operation, the focus position correction operation is performed. Thereafter, the process advances to step S313 to end the exposure. After completion of the exposure, the system control unit 119 determines whether the movement amount of the correction lens 103 during the exposure is within a predetermined range (S314). If the movement amount of the correction lens 103 is within the predetermined range, that is, if it is determined that the calculation result of the shake correction amount is equal to or less than the predetermined amount, the process proceeds to S319, and the photographing operation is ended. If it is determined that the calculation result of the shake correction amount is larger than the predetermined amount, the process proceeds to step S315.

  In step S315, the system control unit 119 executes processing for calculating the image quality deterioration range of the screen peripheral portion. Next, processing for notifying the operator of the calculated image quality deterioration range is performed (S316). Although notification control is performed at the time of shooting a still image, notification control of the image quality degradation range is not performed at the time of shooting a moving image.

  In step S317, the system control unit 119 executes display processing for confirming whether the cutout image is necessary for the operator (user). If it is determined that the user has issued an operation instruction indicating that a clipped image is required by the operation unit 112, the process proceeds to S318. In this case, the system control unit 119 generates data of the specified cutout image. At this time, the system control unit 119 performs control to notify the user of the pixel size of the cutout image. After the data of the cut-out image, or the data and the image data before cut-out are stored in the storage medium in accordance with the user's instruction, the process proceeds to S319. On the other hand, when it is instructed by the user operation in S317 that the cutout image is not necessary, the photographing ends (S319).

  In the present embodiment, the user can recognize camera shake or the like and correct the camera operation by notifying the image quality reduction range associated with the driving of the correction lens. Therefore, the shake correction amount is reduced, and a good image can be obtained. Further, the user is notified of the image quality reduction range associated with the driving of the correction lens on the shooting confirmation screen after shooting, and it is possible to generate the image data generated by cutting out the range with high image quality. The user can instruct generation of data of a captured image (original image) or a cutout image, or data of a captured image and a cutout image to be stored in a storage medium. That is, the user can selectively acquire the cutout image, and can reduce the probability of shooting failure.

  According to the present embodiment, it is possible to acquire a captured image with good image quality while exhibiting the necessary image blur correction effect. In this embodiment, a change in the image quality is determined by comparing the movement amount of the correction lens or the shake correction amount with the threshold value as position information of the image shake correction means, and an example in which notification control is performed when the image quality decreases is described. did. Not limited to this, the change in the image quality may be determined by comparing the correction amount of the focus lens position with a threshold, and notification control may be performed when the image quality is deteriorated. The reason is that, as described in FIG. 9, the movement amount of the correction lens and the correction amount of the focus lens position correspond to each other. This is the same in the embodiments described later.

Second Embodiment
Next, processing of the imaging device according to the second embodiment will be described with reference to FIGS. 15 and 16. In the present embodiment, only matters different from the first embodiment will be described. When the drive speed of the correction lens becomes larger than a predetermined value in photographing, the focus lens can not be interlocked with the drive of the correction lens, and there is a possibility that the image quality correction operation can not be performed. In this case, the image quality is degraded even if the correction lens is at a position corresponding to the image quality allowable range described with reference to FIG. Therefore, in the present embodiment, processing for clipping the image by notifying the user of the image quality deterioration range according to the position information of the correction lens and the information of the driving speed will be described.

  15 and 16 are flowcharts showing processing in the present embodiment. Hereinafter, processing different from those in FIGS. 13 and 14 will be described. The processes of S401 to S407 in FIG. 15 are the same as the processes of S301 to S307 of FIG. If it is determined in S405 that the position of the correction lens is within the predetermined range with respect to the optical axis center, that is, the calculation result of the shake correction amount is equal to or less than the predetermined amount, the process proceeds to S408.

  In step S408, the system control unit 119 compares the drive speed of the correction lens 103 with a predetermined amount (threshold). If it is determined that the driving speed of the correction lens 103 is larger than the predetermined amount (threshold speed), the process proceeds to S406, and the image quality deterioration range at the screen peripheral portion is calculated. If the driving speed of the correction lens 103 is equal to or less than the predetermined amount, the process proceeds to step S409.

  At S409, determination processing is performed as to whether or not the second switch SW2 has been turned on. If it is determined that the second switch SW2 is off, the process returns to S402 in the live view image display state, and the processes of S403 to S405 and S408 are repeatedly executed. On the other hand, if it is determined that the second switch SW2 is on, the process proceeds to S410 in FIG. The processes of S410 to S415 are the same as the processes of S309 to S314 in FIG.

  If it is determined in S415 that the calculation result of the shake correction amount is less than or equal to the predetermined amount, the process proceeds to S418. If it is determined that the calculated amount is larger than the predetermined amount, the process proceeds to S416. The processes of S416, S417, S419, S420, and S421 are the same as the processes of S315 to S319 in FIG.

In step S418, the system control unit 119 compares the driving speed of the correction lens 103 with a predetermined amount (threshold). If it is determined that the driving speed of the correction lens 103 is larger than the predetermined amount (threshold speed), the process proceeds to S416, and the image quality deterioration range in the peripheral portion of the screen is calculated. If the driving speed of the correction lens 103 is equal to or less than the predetermined amount, the process advances to step S421 to end the photographing.
According to the present embodiment, it is possible to notify the user of the image quality deterioration range according to the movement amount of the correction lens and the driving speed, and to acquire the cutout image as needed.

  Although the example in which the present invention is applied to an imaging apparatus has been described above, the present invention is not limited to these embodiments, and various embodiments within the scope of the present invention are also within the technical scope of the present invention include. The imaging apparatus is not limited to the example including the lens barrel having the three-group configuration, and the number of correction lens groups for image blur correction is not limited to one, and two correction lens groups may be used. In that case, the image quality reduction range is calculated from the movement amounts or correction amounts of the two correction lens groups. Further, in the image pickup apparatus having the moving mechanism portion of the image pickup element in place of the correction lens group, the image pickup element can be moved in the plane orthogonal to the optical axis. The image quality reduction range is calculated from the correction amount of camera shake or the like by the moving mechanism unit. An embodiment may be used in which the image blur correction by the correction lens group and the image blur correction by the moving mechanism unit of the imaging device are used in combination. The lens barrel may be attachable to and detachable from the imaging apparatus main body, and the system control unit of the imaging apparatus main body may control the correction lens and the focus lens of the lens barrel.

103 correction lens 104 focus lens 109 display unit 119 system control unit 123 focus control unit 125 image blur correction control unit 126 position correction unit

Claims (13)

Image blur correction control means for calculating a correction amount for correcting the image blur from the detection signal of the shake detecting means, and controlling the correcting means for correcting the image blur of the image captured by the imaging means,
Focus adjustment control means for controlling the drive of a focus lens that performs focus adjustment in conjunction with the drive of the correction means;
And a notification control unit configured to perform control to notify an image range in which the image quality has changed when the image quality of the image captured by the imaging unit is changed by driving of the correction unit. The notification control means determines the change in the image quality by comparing the movement amount of the correction means or the correction amount with a threshold, and performs notification control when the image quality is deteriorated. Imaging device. The correction unit includes a correction lens that corrects an image blur.
The image pickup apparatus according to claim 1, wherein the focusing control unit corrects the position of the focus lens based on position information of the correction lens. The notification control means determines a change in the image quality by comparing the position information of the correction means or the correction amount of the position of the focus lens with a threshold, and performs notification control when the image quality is deteriorated. The imaging device according to any one of claims 1 to 3. The notification control means determines a change in image quality by comparing the speed of the correction means with a threshold value, and performs notification control when the image quality is deteriorated. The imaging device according to. The imaging apparatus according to any one of claims 1 to 5, wherein the notification control unit performs control of calculating and notifying an image range in which the image quality has changed from the exposure time of the imaging unit. The imaging device according to any one of claims 1 to 6, wherein the notification control means does not notify the image range in which the image quality has changed in shooting of a moving image. The notification control means is configured to notify the image range in which the image quality has changed when extracting by the imaging means is completed, and control to extract data of the image range in which the image quality does not change and notify the range of the cutout image The imaging device according to any one of claims 1 to 7, wherein: 9. The imaging according to claim 8, wherein the notification control unit performs control to generate a captured image captured by the imaging unit or data of the cutout image, or data of the captured image and the cutout image. apparatus. The imaging device according to claim 9, wherein an aspect ratio of the cutout image is the same as an aspect ratio of the captured image before extracting an image range. The imaging device according to claim 9, wherein the notification control unit performs control of notifying a pixel size of the cutout image. The imaging device according to any one of claims 1 to 11, wherein the notification control means performs control to display a range in which the image quality is deteriorated in the peripheral portion of the screen of the display means. Calculating a correction amount for correcting the image blur from the detection signal of the shake detection unit, and controlling the correction unit for correcting the image blur of the image captured by the imaging unit;
Controlling driving of a focus lens that performs focusing in conjunction with driving of the correction unit;
Controlling the notification of the image range in which the image quality has changed when the image quality of the image taken by the imaging means is changed by the driving of the correction means.

Images