JP6149366B2 - Angular velocity angular position signal calculation device and blur correction device - Google Patents

Description

  The present invention detects an optical axis shift due to camera shake and panning by calculating an angular velocity and an angular position signal and swings a lens or an image sensor to prevent image blurring. Regarding the mechanism.

  A lens shift system is known as one of optical blur correction mechanisms. In the lens shift method, a gyro sensor and a correction lens are provided in a lens barrel, and the correction lens is driven so as to cancel image blur based on the output of the gyro sensor, thereby preventing image blur due to camera shake. At this time, a configuration is known in which whether the blur is caused by camera shake or panning is identified according to the magnitude of the blur for a predetermined time, and the lens control method is switched according to the type of blur. (See Patent Document 1).

JP-A-5-323436

  However, in this configuration, there is a problem that the image observed by the user is greatly disturbed because the lens moves greatly when the lens control method is switched.

  SUMMARY An advantage of some aspects of the invention is that it provides a lens position correction device that can prevent image distortion when switching a lens control method according to the type of blur.

  An angular velocity angular position signal calculation device according to the present invention is an angular velocity signal calculation device used for camera shake correction, a panning determination means for determining whether panning is being performed, and a first high pass to which an angular velocity signal is input. A filter, an angle calculator that calculates an angle signal based on an output signal from the first high-pass filter, an angle calculator that receives the angle signal, and a switch that turns ON / OFF the input to the angle calculator, The panning determination means is characterized in that when the start of panning is detected, the switch is turned off, and when the end of panning is detected, the variable of the first high-pass filter is reset and the switch is turned on.

  Preferably, the panning determination means detects the angle signal, determines that panning is performed when the angle signal is equal to or greater than the first predetermined value, and sets the switch to the OFF state. With this configuration, it is possible to determine that panning is performed when the lens position is greatly deviated.

  Further, the panning determination means detects the angle signal, determines that panning has ended when the switch is in the OFF state and the angle signal is equal to or less than the second predetermined value, and sets the switch to the ON state. Is preferred. After the panning is completed, the normal vibration correction is restored by turning on the switch.

  The panning determination means detects the angle signal, the panning is finished when the switch is in the OFF state, the angle signal is equal to or smaller than the second predetermined value, and the angular velocity is equal to or smaller than the third predetermined value. It is preferable that the switch is turned on. According to this configuration, the angular velocity can be used to determine the end of panning.

  The first predetermined value is preferably larger than the second predetermined value.

  Note that the angular velocity angle position signal calculation device according to the present invention may be provided in a shake correction device. The angular velocity angle position signal calculation device can prevent blurring by correcting the position of an optical member such as a lens or a CCD.

  According to the present invention, it is possible to prevent image distortion when the lens control method is switched according to the type of blur.

It is a block diagram which shows typically the structure of the camera of this embodiment. It is the front perspective view of the camera-shake correction mechanism of this embodiment, the front view at the time of lock release, and the front view at the time of lock. It is a figure which shows typically the movable range of the correction | amendment lens at the time of lock release and a lock | rock. It is a perspective view which shows typically the motion of the camera by camera shake, and the relationship between a X and Y axis. It is a front view which shows the relationship between a camera main body, a correction lens, and X and Y axes. It is a block diagram of camera shake correction control executed in the lens CPU. It is a block diagram showing the calculating part of FIG. It is a flowchart showing the process process of FIG. It is a graph showing the relationship between the drive position of a lens and angular velocity output by the calculating part of FIG. It is a schematic diagram showing the structure of four high-pass filters of FIG. It is a figure showing the relationship between the lens drive position and angular velocity in correction | amendment of the lens position at the time of camera shake and panning using a prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a camera equipped with a camera shake correction mechanism according to the first embodiment of the present invention. In addition, in this figure, only the structure which concerns on invention is drawn typically.

  In this embodiment, the camera 10 (blur correction device) is a digital single-lens reflex camera in which a lens barrel 12 can be attached to and detached from a camera body 11, for example. In the present embodiment, a camera shake correction mechanism 13 is provided in the lens barrel 11. That is, the camera shake correction mechanism 13 including the correction lens 14 for shake correction is arranged between the imaging lenses 15A and 15B. Light incident from the imaging lens 15A is guided along the optical axis L to the imaging element 16 in the camera body 11 through the correction lens 14 and the imaging lens 15B, and forms an image.

  A camera CPU 17 and a lens CPU 18 are provided in the camera body 11 and the lens barrel 12, respectively. The camera CPU 17 is connected to a main switch 19, a photometric switch 20, and a release switch 21, and is connected to the lens CPU 18 through a plurality of electrodes of a lens mount (not shown) together with a power supply line and a ground. The camera CPU 17 performs various controls of the entire camera, and is connected to various other devices.

  The lens barrel 12 is provided with a blur correction switch 22 for setting on / off of camera shake correction control, and is connected to the lens CPU 18. Further, in the lens barrel 12, angular velocity sensors 23X and 23Y for detecting rotational angular velocities around Y and X axes along the horizontal axis and vertical axis of the camera perpendicular to the optical axis L are provided, and the angular velocity sensors 23X and 23Y are provided. The signal detected at is input to the lens CPU 18. When camera shake correction control is on, the lens CPU 18 moves the correction lens 14 to cancel camera shake based on the angular velocity around each axis detected by the angular velocity sensors 23X and 23Y and lens information such as the focal length. The target position in the power X and Y axis directions is calculated.

  For example, the correction lens 14 is driven by electromagnetic interaction between a coil (not shown) provided in a movable part that holds the correction lens 14 and a yoke provided in a fixed part fixed to the lens barrel 12, to the coil. The current supply is controlled by the X direction drive control unit 24X and the Y direction drive control unit 24Y. The movable part that holds the correction lens 14 is provided with position sensors 25X and 25Y using, for example, a Hall element, and the position of the correction lens 14 is detected and fed back to the lens CPU 18. That is, the lens CPU 18 calculates the current supply amount to the coil from the target position of the correction lens 14 calculated based on the signals of the angular velocity sensors 23X and 23Y and the position of the current correction lens 14 obtained from the position sensors 25X and 25Y. And output to the X direction drive control unit 24X and the Y direction drive control unit 24Y.

  The camera shake correction mechanism 13 is provided with a mechanical lock mechanism 26, which will be described later, and a lock detection sensor 26S for detecting the locked state. The lock mechanism 26 is a mechanism for maintaining the center of the correction lens 14 on the optical axis L. The lock mechanism 26 is controlled by the lock ring control unit 27 based on a command from the lens CPU 18, and the current lock state is set by the lock detection sensor 26S. Is notified to the lens CPU 18.

  The communication port of the lens CPU 18 and the communication port of the camera CPU 17 are connected through the lens mount electrodes as described above, and data communication is performed between them as will be described later.

  FIGS. 2A to 2C are external views of the camera shake correction mechanism 13 of the present embodiment. FIG. 2A is a front perspective view, and FIG. 2B is a front view when unlocking. FIG. 2 (c) is a front view when locked.

  As shown in the figure, the correction lens 14 is held at its approximate center by a movable portion 28 having an annular frame. For example, four protrusions 28P extending outward in the radial direction are provided on the outer peripheral portion of the annular frame of the movable portion 28 at substantially equal intervals along the outer periphery. An annular lock ring 30 is disposed around the annular frame of the movable portion 28, and an annular clearance 29 is provided between the lock ring 30 and the annular frame.

  The inner diameter of the lock ring 30 is such that each protrusion 28P of the movable portion 28 abuts on the inner periphery of the lock ring 30 except for tolerances, and the number of recesses 30P corresponding to the protrusions 28P is formed on the inner periphery. It is formed at substantially equal intervals along. As will be described later, the concave portion 30P defines the movable range of the correction lens 14 in camera shake correction in cooperation with the protrusion 28P.

  The lock ring 30 is accommodated in a casing 31 that has a substantially cylindrical appearance, and can be rotated around the optical axis in the casing (fixed portion) 31. The rotation of the lock ring 30 is performed by, for example, a rack and pinion mechanism provided on the outer periphery of the lock ring 30. That is, a rack portion 30 </ b> R is provided on the outer peripheral portion of the lock ring 30 and meshed with a pinion 32 provided on the casing 31 side, and the pinion 32 is driven by a stepping motor (not shown) fixed in the casing 31. The

  Further, notches 30A and 30B for detecting the locked state from the rotational position of the lock ring 30 are provided on the outer periphery of the lock ring 30, and the photo interrupter that cooperates with the notches 30A and 30B is provided in the casing 31. (Lock detection sensor) 26S is provided. That is, when the lock is released, light is detected in the photo interrupter 26S through the notch 30A as shown in FIG. 2B, and when locked, the light is detected through the notch 30B as shown in FIG. 2C.

  Further, the movable portion 28 is provided with a plurality of flat plate portions 28A extending radially outward from the annular frame, and a coil or the like for driving the movable portion 28 is mounted thereon. The flat plate portion 28A is supported in the casing 31 by a bearing (not shown) in the front and rear thereof, and movement in the optical axis direction is restricted.

  Next, the movable range of the correction lens 14 in this embodiment will be described with reference to FIGS. FIGS. 3A and 3B are diagrams schematically illustrating the movable range of the correction lens 14 when unlocked and locked.

  When the lock shown in FIG. 2B is released, the lock ring 30 is arranged so that the protrusions 28P of the movable portion 28 are positioned in the recesses 30P. At this time, the movement of the movable portion 28 is regulated by the protrusion 28P coming into contact with the side wall of the concave portion 30P, and the movable range of the correction lens 14 is a rectangular region shaded in FIG. ) 33. On the other hand, at the time of locking in FIG. 2C, the lock ring 30 is rotated clockwise from the position in FIG. 2B, and each projection 28P is brought into contact with the arcuate inner peripheral surface of the lock ring 30. . Thereby, the movement of the movable portion 28 in the vertical and horizontal directions is restricted, and the center of the correction lens 14 is fixed so as to coincide with the optical axis L.

  However, since there is a tolerance between the projection 28P and the arcuate inner peripheral surface of the lock ring 30, the correction lens 14 actually has an optical axis as shown in FIG. It can move within a circular shaded area (movable range when locked) 34 centered on L.

  With reference to FIGS. 4 to 6, the camera shake correction process of the present embodiment will be described in more detail. 4 is a perspective view schematically showing the relationship between camera movement caused by camera shake and the X and Y axes, and FIG. 5 is a front view showing the relationship between the camera body 11, the correction lens 14, and the X and Y axes. It is.

  As shown in FIG. 4, in shooting with a camera, image blur that moves in the horizontal direction (X-axis direction) occurs due to rotation (yaw) around the vertical axis (Y-axis), and rotation around the horizontal axis ( The image blur that moves in the vertical direction (Y-axis direction) occurs depending on the pitch. Therefore, the amount of shift in the X-axis direction of the correction lens 14 for canceling image blur in the X-axis direction is determined by detecting the rotational motion around the Y-axis, and the rotational motion around the X-axis is detected. A shift amount in the Y-axis direction of the correction lens 14 for canceling image blur in the Y-axis direction is determined.

  FIG. 6 is a block diagram relating to camera shake correction control executed in the lens CPU 18, and the correction process is executed as an interrupt process at predetermined time intervals (for example, 1 mS), for example.

  Analog angular velocity signals around the Y axis and X axis obtained by the gyros of the angular velocity sensors 23X and 23Y are input to the A / D ports (A / D1, A / D2) of the lens CPU 18, and the A / D calculation unit , 35X and 35Y are converted into digital signals. The angular velocity signal converted into the digital signal is input to the angular velocity angular position calculation device 50, and the driving position of the correction lens 14 in the X and Y directions for canceling image blur is calculated.

  When the blur correction switch 22 input from the port 4 is determined to be in the ON state by the control unit 39, the driving position X in the X-axis direction calculated by the angular velocity angle position calculation device 50 and the Y-axis direction are calculated. Using the drive position Y as the target position of the correction lens 14, the drive position X, the drive position Y and the current position X of the correction lens 14 and the deviation of the current position Y are calculated. For example, processing such as PID calculation is automatically controlled. The calculation is performed in the calculation units 40X and 40Y. Outputs from the automatic control calculation units 40X and 40Y are output to the X direction drive control unit 24X and the Y direction drive control unit 24Y through the ports 1 and 2, and the X direction coils 41X and Y provided in the camera shake correction mechanism 13 are output. The current supplied to the direction coil 41Y is controlled.

  The position of the movable unit 28, that is, the current position of the correction lens 14 in the X-axis and Y-axis directions is calculated by the X-direction drive control unit 24X and the Y-direction drive control unit 24Y based on signals from the hall sensors 25X and 25Y. The current X position signal and Y position signal are input to the lens CPU 18 through the A / D ports (A / D3, A / D4), and the A / D calculation units 43X and 43Y provide the current position X and the current position Y as digital signals. And fed back as described above. Thus, when the shake correction switch 22 is turned on, the target drive position of the correction lens 14 is calculated based on the outputs of the angular velocity sensors 23X and 23Y, and the correction lens 14 is set to the X axis and Y based on this target value. Driven in the axial direction.

  The lens CPU 18 drives the lock motor 44 such as a stepping motor through the lock ring control unit (driver) 27 connected to the port 3 to rotate the lock ring 30 based on the on / off state of the shake correction switch 22. Let That is, the position is switched between the unlocked position (FIG. 2B) and the locked position (FIG. 2C). Whether the lock ring 30 has reached the unlocked position or the locked position is detected by a photo interrupter (lock detection sensor) 26S.

The driving position of the correction lens 14 is calculated by the angular velocity angular position calculation device 50. The calculation process will be described with reference to FIGS. The angular velocity signals output from the A / D arithmetic units 35X and 35Y are input to the high pass filters (first high pass filters) 52X and 52Y in step S01. In step S03, the angular velocity signal is input to the angle calculators 36X and 36Y after the DC component is removed by the high-pass filters 52X and 52Y. In step S05, the angular velocities around the Y axis and the X axis are integrated by the angle calculators 36X and 36Y, and the rotation angles (yaw angle θ _x and pitch angle θ _Y ) around the Y axis and the X axis are calculated. In step S07, the rotation angle is input to the lens drive position calculation units 37X and 37Y after the direct current component is removed by the angle calculation units 54X and 54Y which are high-pass filters. In step S09, the lens driving position calculation units 37X and 37Y cancel the image blur based on the yaw angle and pitch angle and the lens information 38 such as the focal length f stored in the memory. The driving position of the correction lens 14 in the direction is calculated.

  After step S09, based on the camera shake amount, it is determined whether it is camera shake or panning. In the case of panning, correction different from camera shake correction is performed. That is, when a camera shake occurs, the correction lens 14 is continuously driven to correct in the direction opposite to the direction of the blur to prevent image blur. However, during the panning, the correction lens 14 does not pan. It is sufficient to move it gently toward the center before the end. Therefore, after step S11, it is determined whether panning is performed, and the correction lens 14 is driven accordingly. As described in detail below, the drive is switched by turning ON / OFF the switches 60X and 60Y under predetermined conditions. Hereafter, the pan flag indicates whether or not the panning state is set. When the pan flag is 0, panning is not performed but panning is performed when the pan flag is 1.

  In step S11, the driving position of the correction lens 14 calculated in step S09 is greater than or equal to a predetermined value 1 (first predetermined value) by the first position determination units (panning determination means) 56X and 56Y, and the pan flag is 0. It is determined whether or not. The predetermined value 1 is a position relatively deviated from the center of the lens position. When the predetermined value is 1 or more, it is determined that panning has started, and the process proceeds to step S13. The pan switch is set to 1 and the switches 60X and 60Y are OFF by the first switch control devices (panning determination means) 58X and 58Y. It is said.

  That is, during the panning, the angular velocity signal is not transmitted from the high pass filters 52X and 52Y to the angle calculators 36X and 36Y. As will be described in detail below, when the switches 60X and 60Y are turned off, the correction lens 14 is controlled differently from the camera shake correction. On the other hand, when the driving position of the correction lens 14 is smaller than the predetermined value 1 in step S11, it is determined that panning is not performed, so the pan flag remains 0 and the process proceeds to step S15.

  After the process of step S11 or step S13, in step S15, the driving position of the correction lens 14 calculated in the lens driving position calculation units 37X and 37Y by the second position determination units (panning determination means) 62X and 62Y is a predetermined value 2. Whether or not the pan flag is 1 is determined. The predetermined value 2 (second predetermined value) is a value smaller than the predetermined value 1.

  When the condition of step S15 is not satisfied, it is determined that panning is still performed, and the process proceeds to step S21. In step S21, the current position of the correction lens 14 is input to the lens drive position calculation units 37X and 37Y. In step S23, automatic control calculation for obtaining the drive position of the correction lens 14 is performed, and then correction is performed in step S25. The lens 14 is driven to the driving position.

  Similarly, when the second position determination unit 62X, 62Y determines that the pan flag is 1 and the driving position of the correction lens 14 is equal to or less than the predetermined value 2 in step S15, the process proceeds to step S17.

  In step S17, when the angular velocity determination units (panning determination means) 64X and 64Y determine that the angular velocities transmitted from the high-pass filters 52X and 52Y are larger than the predetermined value 3 (third predetermined value), panning is still performed. In step S21, the correction lens 14 is driven through the same process as described above. On the other hand, when the angular velocity is equal to or smaller than the predetermined value 3 in step S17, it is determined that the panning is finished.

  When the panning is completed, in step S19, the second switch control device (panning determination means) 68 sets the pan flag to 0, clears the variables of the high-pass filters 52X and 52Y, and sets the switches 60X and 60Y to the ON state. Is done. Thereafter, the process proceeds to step S21, and the correction lens 14 is driven through steps S23 and S25 as described above.

  Referring to FIG. 9, changes in the drive position of the correction lens 14 due to ON / OFF switching of the switches 60X and 60Y are shown. In the above-described step S13, that is, when the driving position of the correction lens 14 exceeds the predetermined value 1, the switches 60X and 60Y are turned off. At this time, signals are not transmitted from the high pass filters 52X and 52Y to the angle calculators 36X and 36Y.

Here, the high-pass filter 54X shown in FIG.
“VOUT (i) = VIN (i) −ΣVOUT (i−1) / time constant” (Expression 1)
Is defined. VIN (i) is the i-th angular velocity output from the angle calculator 36X, and VOUT (i) is the i-th yaw angle output with the DC component removed by the high-pass filter 54X. Note that the second term of Equation 1 represents a general moving average, and a variable average interval is determined by a variable i. When the switch 60X is in the OFF state, the output value from the high pass filter 52X is not updated, so VIN (i) becomes a fixed value and VOUT (i) decreases monotonously.

  That is, the drive position of the correction lens 14 approaches 0 based on the time constant of the high-pass filter 54X, as shown by the change in the drive position from time a to time b in FIG. This process is similarly performed in the high-pass filter 54Y.

  At the time of the above-described step S19, that is, at the time b when the panning is finished, the switches 60X and 60Y are turned on by the second switch control device 68, and the outputs of the high-pass filters 52X and 52Y are the high-pass filter 54X, 54Y begins to be transmitted.

  Here, the configuration of the high-pass filters 52X and 52Y is the same as that in Expression 1. However, VIN (i) in the high-pass filters 52X and 52Y is the i-th output from the A / D arithmetic units 35X and 35Y, and VOUT (i) is the i-th angular velocity output from the high-pass filters 52X and 52Y. . At time b, the switches 60X and 60Y are turned on, and at the same time, the second switch controller 68 resets the moving average variable i of the high-pass filters 52X and 52Y. By resetting the variable i, the outputs from the high-pass filters 52X and 52Y are substantially zero. That is, the value output via the high-pass filters 52X and 52Y and the high-pass filters 54X and 54Y immediately after time b when the switches 60X and 60Y are turned on is the value immediately before the switches 60X and 60Y are turned on. equal.

  Accordingly, the output of the high-pass filters 52X and 52Y is not instantaneously added to the output of the high-pass filters 54X and 54Y at time b, so that the drive position of the correction lens 14 is continuously at the time b. Change.

  Thus, by resetting the variables of the high-pass filters 52X and 52Y at the end of the panning state, the displacement of the driving position of the correction lens 14 becomes smooth, and the uncomfortable feeling that the image flows greatly is reduced. FIG. 11 is a diagram showing drive control of the correction lens 14 at the time of conventional panning, but the drive position of the correction lens 14 is discontinuous due to switching of the time constant at the start and end of panning. The sense of incongruity due to sudden changes in the image was great.

  Note that an XY determination element 66 is provided before the input of the second switch control device 68, but the XY determination element may be either AND or OR. That is, the pan flag is set to 0 when both the angular velocity determination units 64X and 64Y satisfy the conditions in step S19 of FIG. 8, or the pan flag is set to 0 when either one of the XYs satisfies the condition. Also good. Furthermore, although the position of the correction lens 14 is corrected in the present embodiment, the position of an image sensor such as a CCD may be corrected.

36X, 36Y Angle calculation unit 50 Angular velocity angle position signal calculation device 52X, 52Y High-pass filter (first high-pass filter)
54X, 54Y Angle calculation unit 56X, 56Y First position determination unit (panning determination means)
58X, 58Y first switch control device (panning determination means)
62X, 62Y 2nd position determination part (panning determination means)
64X, 64Y angular velocity determination unit (panning determination means)
68 Second switch control device (panning determination means)
60X, 60Y switch θ _X , θ _Y angular velocity signal

Claims (6)

An angular velocity angle position signal calculation device used for camera shake correction,
Angular velocity signal calculating means for calculating the angular velocity signal;
A first high-pass filter to which the angular velocity signal is input;
An angle calculator that calculates an angle signal based on an output signal from the first high-pass filter;
A switch for turning ON / OFF the input to the angle calculation unit;
A second high-pass filter to which the angle signal output from the angle calculator is input;
Panning determination means for determining whether panning is being performed according to the output value of the second high-pass filter,
The panning determination means turns off the switch when the start of panning is detected, and resets the variable of the first high-pass filter and turns on the switch when the end of panning is detected. An angular velocity angle position signal calculation device as a feature. The panning determination means includes
2. The angular velocity angle position signal calculation device according to claim 1, wherein the angle signal is detected, panning is determined when the angle signal is equal to or greater than a first predetermined value, and the switch is turned off. The panning determination means includes
When the angle signal is detected, the switch is in an OFF state, and the angle signal is equal to or less than a second predetermined value, it is determined that panning has been completed, and the switch is turned on. The angular velocity angle position signal calculation apparatus according to claim 2. The panning determination means includes
When the angle signal is detected, the switch is in an OFF state, the angle signal is equal to or smaller than a second predetermined value, and the angular velocity is equal to or smaller than a third predetermined value, it is determined that panning is finished. The angular velocity angle position signal calculating device according to claim 2, wherein the switch is turned on.   The angular velocity angular position signal calculation device according to claim 3 or 4, wherein the first predetermined value is larger than the second predetermined value.   A blur correction device comprising the angular velocity angle position signal calculation device according to claim 1.

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