JP4046707B2 - Image blur correction apparatus in imaging apparatus - Google Patents

Description

  The present invention relates to an image blur correction apparatus that performs camera shake correction in an imaging apparatus such as a video camera, a digital video camera, or a digital still camera having a moving image shooting function.

  In recent years, consumer video movies have become smaller and lighter, and optical zooms have increased in magnification, and their usability has improved dramatically. For this reason, a video movie has become an ordinary video device for general users. On the other hand, however, the reduction in size, weight, and high magnification of the optical zoom can cause video screen users who are not proficient in shooting to obtain a stable screen if camera shake occurs during shooting. It was.

  For this reason, many video movies equipped with a camera shake correction device that reduces problems caused by camera shake have been developed and commercialized. For example, as described in Japanese Patent Application Laid-Open No. 4-18515, this video movie camera shake correction device corrects camera shake by the user by moving the correction lens group in two directions perpendicular to the optical axis. A method for obtaining a stable image has been proposed.

Also, a system as described in Patent Document 1 has been proposed in order to respond to operations such as panning and tilting for following a subject that occurs during actual photographing or changing the subject. According to this publication, in a video movie or the like, the usage situation may differ between horizontal blur and vertical blur. Assuming a consumer video movie, it is described that the frequency of horizontal panning is high, but the frequency of vertical tilting is low, and its control characteristics are compared to that of vertical shake correction. Direction blur correction operation is suitable for panning operation. On the contrary, the vertical direction is suitable for the anti-vibration effect. That is, with respect to the shake correction operation in the horizontal direction, a method of applying torque for returning the shake correction operation in the vertical direction to the center of the actuator is weakened.
Japanese Patent Laid-Open No. 2-287423

  However, recently, as shown in FIG. 7, even in the form of a conventional digital still camera that captures a still image, a moving image capturing function similar to a video movie has been added. Therefore, when shooting with this camera, as shown in FIG. 7A, it is common to hold the normal camera 1 in an upright posture and take a picture on a horizontally long screen. A panning operation for moving the screen in the horizontal direction in a posture and a tilting operation for moving the screen in the vertical direction are performed. However, when the subject is vertically long, for example, as shown in FIG. 7B, a vertically long image is shot with the camera 1 rotated 90 degrees around the axis of the shooting direction. Since the panning operation and tilting operation in that case are reversed, if the panning operation and tilting operation are fixed as in the conventional case, the performance of the shake correction device deteriorates, and a good photographed image without camera shake. There was a problem that could not be obtained.

  The present invention solves the above-described problems, and even when shooting in an upright posture or shooting in a vertical posture, an imaging device capable of accurately selecting a shake correction operation and capturing a good screen without blurring An object of the present invention is to provide an image blur apparatus.

The invention according to claim 1 is based on an image sensor that converts an image incident through the lens group into an electrical signal, a shake detection unit that detects a shake of the image pickup apparatus, and a shake detected by the shake detection unit. An image blur correction drive mechanism that corrects a motion of an image on the image sensor due to a blur of the imaging device in a yawing direction and a pitching direction of the imaging device, an attitude detection unit that detects an attitude of the imaging device, and the blur Based on the blur detected by the detection means, the image blur correction drive mechanism is driven in the yawing direction and the pitching direction of the imaging device, thereby correcting the movement of the image on the image sensor due to the blur of the imaging device. Control mode at the time of camera shake correction, if the posture of the imaging device detected by the posture detector is an upright posture, a response to the detected shake Is controlled in the yawing direction by the image blur correction drive mechanism so that the response is smaller than the response at the time of camera shake correction, and when the detected posture is a vertical posture, the response is The control mode at the time of panning operation for controlling the driving in the pitching direction by the image blur correction drive mechanism to be smaller than the response at the time of camera shake correction, and the posture of the imaging device detected by the posture detection means In the case of the posture, the driving in the pitching direction by the image blur correction drive mechanism is controlled so that the response to the detected blur becomes smaller than the response at the time of the camera shake correction, while the detected posture is In the case of the vertical orientation, the yaw direction by the image blur correction drive mechanism is reduced so that the response is smaller than the response at the time of camera shake correction. Those equipped with an image blur correction control means and a control mode at the time of tilting operation of controlling the movement.

  According to the first aspect of the present invention, the image blur correction control means outputs an appropriate control signal based on the posture of the imaging device detected by the posture detection means and the photographing operation detected by the motion detection means, The correction lens group can be shake-corrected via the image blur correction drive mechanism. Therefore, regardless of the orientation of the imaging device held by the photographer, the correction lens group can be appropriately driven for camera shake correction even in a shooting orientation in which an upright posture or a vertical orientation is mixed. No stable image can be obtained. In addition, the image blur correction control means can appropriately drive the correction lens group to perform blur correction in response to the operation of the imaging device in each of the camera shake, panning, and tilting operations that cause camera shake. As a result, a good image without blurring can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an image blur correction apparatus for an image pickup apparatus according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a block diagram showing a camera shake correction device for a digital camera (electronic camera) which is an imaging device according to the present invention. The imaging optical system 2 of the camera 1 includes three lens groups L1, L2, and L3. The intermediate lens group L2 serves as a correction lens group in two directions X and Y that are perpendicular to each other in a plane perpendicular to the optical axis Z. By moving in the direction, the optical axis Z is decentered to play a role in correcting image movement.

  The yawing drive correction unit 3x and the pitching drive correction unit 3y pass the correction lens group L2 through the image blur correction drive mechanism 20 having the yawing actuator 20x (first actuator) and the pitching actuator 20y (second actuator), and the imaging optical system. In the plane orthogonal to the two optical axes Z, drive control is performed in two directions X and Y that are orthogonal to each other. Here, the X direction in the camera 1 is referred to as a yawing direction, and the Y direction is referred to as a pitching direction.

  The position detection means 4 is means for detecting the position of the L2 lens group by the light emitting element 4a and the light receiving element 4b shown in FIG. 2, and drives and controls the correction lens group L2 together with the yawing drive control unit 3x and the pitching drive control unit 3y. A feedback control loop is formed. The yawing drive control unit 3x and the pitching drive control unit 3y constitute a correction drive control unit 3 that controls the optical axis Z of the imaging light.

  The solid-state imaging device 11 disposed at the end of the optical axis Z converts an image incident through the imaging optical system 2 into an electrical signal. The video signal output from the solid-state imaging device 11 is analog signal processing. The analog video signal such as gamma processing is input to the means 12, and the analog video signal is converted into a digital signal by the A / D conversion means 13, and then converted into a digital video signal by the digital signal processing means 14. Digital signal processing such as noise removal and contour enhancement is performed. The solid-state image sensor drive control means 15 shown in FIG. 1 is a drive control means for driving and controlling the solid-state image sensor 12.

The angular velocity sensors 5x and 5y are for detecting the movement of the camera 1 itself including the imaging optical system 2, and both positive and negative depending on the direction of movement of the camera 1 based on the output when the camera 1 is stationary. These angular velocity signals are output, and two angular velocity sensors 5x and 5y are provided to detect movements in two directions, the yawing direction and the pitching direction, respectively. As described above, the angular velocity sensors 5x and 5y constitute an operation detection means (blur detection means) 5 for detecting the movement of the camera 1 due to camera shake and other vibrations. In this motion detection means 5, the output signals output from the angular velocity sensors 5x and 5y are removed from the DC drift component in the unnecessary band components contained in the output signals by the high pass filters (HPF) 6x and 6y, and further reduced. The passband filters (LPF) 7x and 7y remove the resonance frequency component and noise component of the sensor from unnecessary band components included in the output signal. The amplifier 8x, after the level adjustment of the output signal performed by the 8y, converted A / D converter 9x, amplifier 8x by 9y, the analog output signal output from 8y to a digital signal, the digital output signal Is input to the image blur correction control means (microcomputer) 10.

Here, with reference to the exploded perspective view of FIG. 2, the image blur correction drive mechanism 20 that drives and controls the correction lens unit L2 in the lens barrel will be described.
The fixed frame 21 holds a yawing movement frame 22 slidable in the yawing direction via yawing shafts 22a and 22b. The yawing movement frame 22 is pitched via two pitching shafts 23a and 23b. A pitching frame 23 is slidable in the direction, and the correction lens group L2 is fixed to the pitching frame 23.

  The coils 24x and 24y are fixed to the pitching movement frame 23, respectively. On the other hand, the fixed frame 21 holds a magnet 25x and a yoke 26x corresponding to the coil 24x, and a pitching actuator (actuator comprising a coil and a magnet) that drives and corrects the correction lens group L2 in the pitching direction via the pitching moving frame 23. 20x is configured. Similarly, a magnet 25y and a yoke 26y corresponding to the coil 24y are held on the fixed frame 21, and a yawing actuator (actuator comprising a coil and a magnet) that drives and corrects the correction lens group L2 in the yawing direction via the pitching movement frame 23. 20y is configured.

  Further, the light emitting element 4a constituting the position detecting means 4 is fixed to the pitching movement frame 23, and the light receiving element 4b fixed to the fixed frame 21 receives the projection light of the light emitting element 4a, and the correction lens group L2 Two-dimensional position coordinates are detected.

  The yawing current value detection unit 30x shown in FIG. 1 detects the current value flowing through the coil 24x when the yawing actuator 20x is operated. Similarly, the pitching current value detection unit 30y is used when the pitching actuator 20y is operated. It detects the value of the current flowing through the coil 24y, and constitutes a posture detection means 30 for detecting the posture of the camera.

  The image blur correction control means 10 shown in FIG. 1 determines the posture (upright posture or vertical posture) of the camera 1 based on the detection values of the yawing current value detection unit 30x and the pitching current value detection unit 30y. Unit 16, a blur correction characteristic storage unit 17 including a non-volatile memory (for example, EEPROM) storing a control signal of image blur correction characteristic necessary for driving control of the L2 lens group necessary for motion correction, and an operation detection unit 5 is used to determine the shooting operation of the camera 1, and the motion determination unit 18 that obtains the motion direction and acceleration, the posture determination unit 16, the motion compensation characteristic storage unit 17, and the motion determination unit 18 output signals. A gain adjusting unit 19 that adjusts the gain of the correction operation corresponding to the characteristics is provided.

  The operation determination unit 18 performs filtering, integration processing, phase compensation, gain adjustment, clip processing, and the like on the output signals of the angular velocity sensors 5x and 5y captured via the A / D conversion means 9x and 9y, The photographing operation of the camera 1 is determined. Further, the gain adjustment unit 19 determines the driving direction of the shake correction operation from the posture of the camera 1 determined by the posture determination unit 16, selects the output side of the control signal, and uses the signal output from the operation determination unit 18 to Based on the data in the shake correction characteristic storage unit 17, the drive control amount of the correction lens unit L2 necessary for shake correction is obtained. For example, in the case of the upright posture shown in FIG. 7A, the control signals for the panning operation and the vertical camera shake operation are sent to the yawing drive control unit 3x, and the control signals for the tilting operation and the horizontal camera shake operation are pitched. It is output to the drive control unit 3y side. On the other hand, in the case of the vertical orientation shown in FIG. 7B, the control signals for the panning operation and the horizontal camera shake operation are on the pitching drive control unit 3y side, and the control signals for the tilting operation and the vertical camera shake operation are It is output to the yawing drive controller 3x side. Further, the control signal from the gain adjusting unit 19 is output to the yawing drive control unit 3x and the pitching drive control unit 3y via the D / A conversion units 31x and 31y constituting the correction drive control means 3, respectively, and the yawing drive control is performed. The yawing actuator 20x and the pitching actuator 20y are output from the unit 3x and the pitching drive control unit 3y, and the correction lens group L2 is controlled and driven to correct the movement of the image.

Here, the image blur characteristic and the operation of the gain adjusting unit 19 will be described.
By setting the gain at the time of panning operation or tilting operation smaller than the gain setting value at the time of normal camera shake correction, the image blur correction control means 10 sends it to the yawing drive control unit 3x or the pitching drive control unit 3y. And the response to the image blur correction drive mechanism 20 is reduced. As a result, it is possible to prevent the image motion from being erroneously corrected based on the camera shake correction characteristic during panning or tilting.

  FIG. 3 is an example of a gain switching method when the normal camera shake correction state shifts to the panning correction state or the tilting correction state. At the time of panning correction or tilting correction, the gain of the correction operation is changed by the gain adjusting unit 19, but if the switching is performed in a short time, the correction characteristics of the shake may change abruptly and a sense of incongruity may occur. There is. Therefore, the time when panning or tilting is performed is t1, and the gain is gradually changed from time t1. Conversely, the gain is gradually changed in the same manner when shifting from the panning correction state or the tilting correction state to the camera shake correction state. Further, since it is known that the frequency of the panning operation is higher than that of the tilting operation, the responsiveness of the image blur correction drive mechanism 20 is lowered by lowering the gain during the panning operation compared with the tilting operation. It is configured to perform control without a sense of incongruity. The gain at this time has a relationship of G0> G1> G2.

  Further, current value detection and posture determination by the yawing current value detection unit 30x and the pitching current value detection unit 30y in the posture determination unit 16 will be described. In photographing in a normal upright posture as shown in FIG. 7A, the posture of the pitching moving frame 23 is as shown in FIG. At this time, in order to hold the correction lens unit L2 at the center of the optical axis Z in the Y direction, the weights of the correction lens unit L2, the pitching holding frame 21, and the coils 24x and 24y are applied in the gravity direction (Y direction). It is necessary to pass a current to lift the weight of the coil 24y. The current value at that time is Iy1 shown in FIG. Further, with respect to the X direction, since it is not necessary to consider the weight of the correction lens unit L2 that is held at the center of the optical axis Z, the current value that flows through the coil 24x is Ix2, which is smaller than Iy1. Conversely, in the vertical orientation rotated 90 ° around the optical axis Z as shown in FIG. 7B, the posture of the pitching movement frame 23 is as shown in FIG. 4B. At this time, in order to hold the L2 lens group at the center of the optical axis with respect to the X direction, the weight of the yawing holding frame 22 in addition to the correction lens group L2, the pitching holding frame 21, the coils 24x and 24y is set in the gravity direction (X direction). Therefore, it is necessary to pass a current to lift the weight of the coil 24x. The current value at that time is Ix1 which is larger than Iy1. Regarding the Y direction, since it is not necessary to consider the weight of the correction lens unit L2 that is held at the center of the optical axis Z, the current value that flows through the coil 24y is Iy2, which is smaller than Ix1. As described above, since the drive current value flowing in the coils 24x and 24y is determined by the posture of the camera 1 to be photographed, the posture determination unit 16 can determine the posture of the camera 1 by detecting the current value. It becomes possible.

The operation of the image blur correction apparatus configured as described above will be described.
When current is supplied to the coils 24x and 24y of the pitching moving frame 23 from an external circuit, the pitching moving frame 23 having the correction lens group L2 is perpendicular to the optical axis Z by a magnetic circuit formed by the actuators 20x and 20y. They are moved in two directions X and Y directions orthogonal to each other in the plane. Further, the position of the pitching moving frame 23 is detected with high accuracy because the light receiving element 5b detects the light of the light emitting element 5a of the position detecting means 5. In other words, the image blur correction drive mechanism 20 moves the correction lens group L2 in the X and Y directions within a plane orthogonal to the optical axis Z, so that the image incident on the solid-state imaging device 11 via the imaging optical system 2 is moved. Correction can be performed.

Next, the procedure performed by the image blur correction control means 10 will be described with reference to the flowchart of FIG.
First, in step 1 (S1), the posture determination unit 16 determines the posture of the camera 1 based on the current values obtained by the yawing current value detection means 17x and the pitching current value detection means 17y. For example, when the current value flowing through the coil 24x is Ix2 and the current value flowing through the coil 24y is Iy1, it can be seen that the camera 1 is in the upright posture of FIG. Therefore, in this upright posture, the yawing movement frame 22 moves in the X direction, and the pitching movement frame 23 moves in the Y direction (gravity direction).

  In step 2 (S2), the output signals of the angular velocity sensors 5x and 5y of the motion detection means 5 are taken into the image blur correction control means 10. In step 3 (S3), the motion determination unit 18 determines whether the motion of the camera 1 is a panning motion, a tilting motion, or a camera shake motion based on the angular velocity. In the determination method, at the time of panning or tilting, for example, the angular velocity obtained by the angular velocity sensors 5x and 5y is obtained by using the tendency that the angular velocity has a sign in the same direction and a state where the sign is equal to or higher than a certain level. If the predetermined threshold value is continuously exceeded for a certain period of time, it is determined that the operation is a panning operation or a tilting operation. If an angular velocity that has not been determined to be a panning operation or a tilting operation is detected, it is determined that the camera shake is normal, and step 4 (S4) is jumped to and processing from step 5 (S5) onward is executed. .

  The next step 4 (S4) to step 7 (S7) are operations in the gain adjusting unit 19. That is, in step 5 (S5), a high-pass filter (HPF) is used to remove low-frequency components such as temperature drifts from the outputs of the angular velocity sensors 5x and 5y taken into the image blur correction control means 10. Perform bandwidth limitation. Further, in step 6 (S6), an integration process is performed on the outputs of the angular velocity sensors 5x and 5y after the filtering in step 5 (S5), and the angle is obtained from the angular velocity. Step 7 (S7) is a step of performing gain adjustment on the angle information of the movement of the camera 1 obtained from the output of the angular velocity sensor 5 in Step 6 (S6), and the gain G is set to Step 6 in Step 7 (S7). Multiply the output of (S6).

  The above is the case where the panning operation or the tilting operation is not determined in step 3 (S3). Conversely, when the operation determining unit 18 determines that the panning operation or the tilting operation is reversed, the gain adjusting unit 19 A process for limiting the camera shake correction operation is added. That is, the movement of the camera 1 by the panning operation or the tilting operation is a movement having a lower frequency component than the normal camera shake operation. Therefore, at the time of panning operation or tilting operation, the response to the low frequency band of a series of processing systems executed by the image blur correction control means 10 is lowered. This is intended to prevent the correction lens unit L2 from following the movement of the camera 1 due to the panning operation or the tilting operation, and as a result, erroneously during the panning operation or the tilting operation. Prevents camera shake correction for image movement. Accordingly, during the tilting operation, the pitching movement frame 23 is driven and controlled to have the control characteristics shown in FIG. 3A, and during the panning operation, the yawing movement frame has the control characteristics shown in FIG. 3B. 22 is driven and controlled.

  Conversely, when the current value flowing through the coil 24x is Ix1 and the current value flowing through the coil 24y is Iy2, it can be seen that the camera 1 is in the vertical orientation of FIG. 7B. Therefore, in this posture, the yawing movement frame 22 moves in the Y direction (gravity direction), and the pitching movement frame 23 moves in the X direction. For this reason, during the tilting operation, the yawing movement frame 22 is driven and controlled so as to have the control characteristics shown in FIG. Further, during the panning operation, the pitching movement frame 23 is driven and controlled so that the control characteristics shown in FIG. 3B are obtained, and the movement directions of the yawing movement frame 22 and the pitching movement frame 23 in the upright posture are reversed. Thus, the correction operation of the yawing actuator is opposite to the correction operation of the panning actuator.

  As described above, according to the above-described embodiment, the image blur correction control means (microcomputer) 10 includes the gain adjustment unit 19 that adjusts the gain of the control signal for controlling the correction lens unit L2, and includes the pitching direction. By setting the control characteristics in the yawing direction to be different from each other, a good camera shake correction characteristic can be realized. Further, during panning operation or tilting operation, by reducing the gain compared to the normal camera shake state and restricting the motion correction performance by the correction lens unit L2, the motion of the image is erroneously detected during the panning operation or tilting operation. It is possible to prevent camera shake correction.

  Further, the posture detection unit 9 that detects the current values of the pitching actuator 20x and the yawing actuator 20b enables the posture determination unit 16 to determine the shooting posture of the camera 1. Based on this shooting posture, the panning operation and the chill Since the operation direction during the shooting operation and the gain of the correction operation are adjusted, it is possible to always obtain optimal control characteristics in that direction without being influenced by the posture of the camera 1 used by the photographer. The image will not be disturbed.

  Further, as a means for detecting the posture of the camera 1, the current value of the actuators 20x and 20y for driving the correction lens group L2 is measured, so that it is not necessary to use a dedicated sensor such as an angle sensor, resulting in an increase in cost. There is nothing.

  In the above-described embodiment, the current value detectors 9x and 9y detect the current values of both the yawing actuator 20x and the pitching actuator 20y. However, even if only one of the current values is detected, the camera 1 The posture can be specified. However, by detecting both current values, even if an abnormality occurs in one current value detection unit, it can be determined more accurately.

  Although the digital camera 1 has been described as an example of the image pickup apparatus, any apparatus may be used as long as the camera shake correction apparatus is mounted. For example, a silver salt film may be used. The shape of the camera 1 is not limited to that described in the above embodiment.

Furthermore, in the above embodiment, the image blur correction drive mechanism 20 is configured by an actuator composed of a magnet and a coil, but this is not the only form.
Furthermore, the vertical posture shown in FIG. 7B may be a posture obtained by inverting the illustrated posture by 180 degrees.

1 is a configuration diagram illustrating a first embodiment of an image blur correction device of an imaging apparatus according to the present invention. FIG. It is an exploded perspective view showing an image blur correction drive mechanism of the image blur correction device. An example of the gain change method of the image blur correction apparatus is shown, (a) is a graph showing gain change during tilting operation, and (b) is a graph showing gain change during panning operation. The pitching movement frame of the image blur correction drive mechanism of the image blur correction device is shown, (a) is a front view in an upright state, and (b) is a front view in a portrait orientation. It is a graph which shows the magnitude | size of the electric current value of the actuator in the electric current value detection part of the image blurring correction apparatus. It is a flowchart which shows the process of the image blur correction control means of the image blur correction apparatus. FIG. 6A is a diagram illustrating a camera posture, in which FIG. 9A is an explanatory diagram illustrating a camera and an image in an upright state, and FIG.

Explanation of symbols

L2 correction lens group Z optical axis 1 camera 2 imaging optical system
3x yawing drive control unit 3y pitching drive control unit 4 position detection unit 5x, 5y angular velocity sensor 10 image blur correction control unit 16 posture determination unit 17 blur correction characteristic storage unit 18 operation determination unit 19 gain adjustment unit 20 image blur correction drive mechanism 20x Yawing actuator 20y Pitching actuator 21 Fixed frame 22 Yawing movement frame 23 Pitching movement frame 30 Posture detection means 30x Yawing current value detection part 30y Pitching current value detection part 31 Correction drive control means

Claims (1)

An image sensor that converts an image incident through the lens group into an electrical signal;
Blur detection means for detecting blur of the imaging device;
An image blur correction drive mechanism that corrects the movement of the image on the image sensor due to the blur of the imaging device with respect to the yawing direction and the pitching direction of the imaging device based on the blur detected by the blur detection unit;
Attitude detection means for detecting the attitude of the imaging device;
Based on the shake detected by the shake detection means, the image blur correction drive mechanism is driven in the yawing direction and the pitching direction of the image pickup device, so that the movement of the image on the image sensor due to the shake of the image pickup device is detected. Control mode for correcting camera shake,
When the posture of the imaging apparatus detected by the posture detection unit is an upright posture, the image blur correction drive mechanism causes the response to the detected blur to be smaller than the response at the time of the camera shake correction. While controlling the driving in the yawing direction, when the detected posture is a vertical posture, the pitching direction by the image blur correction drive mechanism is such that the responsiveness is smaller than the responsiveness at the time of the camera shake correction. Control mode during panning operation to control the drive of
When the posture of the imaging device detected by the posture detection means is an erect posture, the image blur correction drive mechanism is such that the response to the detected blur is smaller than the response at the time of the camera shake correction. When the detected posture is a vertical posture, the yawing by the image blur correction drive mechanism is controlled so that the response is smaller than the response at the time of the camera shake correction. Control mode during tilting operation to control direction drive
An image blur correction apparatus in an imaging apparatus , comprising: an image blur correction control unit having the image blur correction control unit .

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