JP2008064847A - Image blur correction controller, control method, imaging apparatus and imaging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image blur correction controller, a control method, an imaging apparatus and an imaging method, wherein image blur correction is performed to obtain a still picture having good image quality without deteriorating the optical performance of an imaging part. <P>SOLUTION: A control target value calculation part 12 which performs the image blur correction based on an angular velocity signal 102 is equipped with: a first angle signal generation part to convert the angular velocity signal 102 into an angle signal 105 with a low frequency component removed; a second angle signal generation part to generate an angle signal 106 obtained by acquiring the instantaneous value of the angle signal 105 when starting opening a shutter, and temporally integrating the angular velocity signal 102 while the shutter is opened and adding the obtained value to the instantaneous value; a switching circuit 24 to select the angle signal 105 when the shutter is closed and the angle signal 106 when the shutter is opened; and a position arithmetic calculation part 25 to calculate a control target value 103 based on an angle signal 107 for correction selected by the switching circuit 24. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image blur correction control device, a control method, an imaging device, and an imaging method.

2. Description of the Related Art Conventionally, in an imaging apparatus such as a camera or a video camera, an image shake correction function that detects a shake of the apparatus main body and corrects an image position shift on the imaging surface due to the shake in order to prevent image quality deterioration due to, for example, camera shake. The one with is known.
Causes of camera shake include normal imaging operations such as panning and tilting that move the camera following the subject, in addition to camera shake. Therefore, generally, low-frequency components of shake are allowed as normal movement, and high-frequency components are determined to be camera shake and image shake correction is performed. However, in the camera shake correction, as the response is made to a lower frequency, the image blur is reduced. Therefore, the frequency for determining the camera shake is adjusted according to the situation.
For example, Patent Document 1 discloses a shake correction apparatus that detects camera shake using an angular velocity sensor, calculates a shake angle after cutting low-frequency components of the angular velocity signal using a filtering unit, and performs image shake correction accordingly. In the imaging apparatus, it is described that the cutoff frequency of the filtering means is changed according to the focal length and the maximum correction angle. As image blur correction methods, electronic image blur correction in which image data is cut out and moved, and optical image blur correction in which a part of an imaging lens is shifted in a lens barrel are described.
The prior art of Patent Document 1 describes panning control in which when the integral value of the angular velocity exceeds a certain value, it is determined as panning and the cutoff frequency is set high. According to this panning control, the amount of image blur correction is reduced during panning, so that the image follows the moving direction of the camera, and image blur correction beyond the correction range can be prevented from occurring.
Patent Document 2 describes an imaging method and an imaging apparatus that perform panning control by varying a cutoff frequency by providing a pan / tilt determination circuit. In this case, the image blur correction uses an electronic method, and when the shooting mode is the moving image recording mode, a smooth image can be obtained by performing an image shifting process in addition to the image cutout process. In this case, only the image clipping process is performed.
JP 2003-219265 A (FIGS. 1-3) Japanese Patent No. 3697050 (FIGS. 1, 2, and 5)

However, the conventional image blur correction control apparatus, control method, imaging apparatus, and imaging method as described above have the following problems.
For example, in order to remove an image blur with a digital still camera and take a picture, it is desirable to respond to a very low frequency fluctuation such as panning. However, in response to low-frequency fluctuations, when the optical component is moved for image correction, the optical component is greatly displaced from the optical center. Further, when image correction is performed by a method of cutting out data, an image at a position away from the optical center is cut out. In each of these cases, there is a problem that the image is deteriorated because the image is taken using an image deviated from the optical center with good optical performance.
In the techniques described in Patent Documents 1 and 2, image blur correction is controlled by switching the cutoff frequency of the filtering means. For this reason, for example, there is no problem when switching the cut-off frequency from the low side to the high side as in panning control, but conversely, when panning control is ended and the cut-off frequency is switched from the high side to the low side, that is, When switching from moving image capturing to still image capturing, there is a problem that the amount of image blur correction increases rapidly.
For example, in the case of electronic image blur correction, there is a possibility that the correction range by image cutout may be exceeded. In addition, in the case of optical image blur correction, for example, when the imaging lens or imaging lens barrel is moved by servo control, it takes time until the control is stabilized due to the occurrence of relaxation vibration, and the optical performance during that time is reduced. There is a problem that the image quality deteriorates due to deterioration.
In addition, the electronic image blur correction described in Patent Document 2 can cope to some extent even when the image blur correction amount increases in the moving image recording mode, but the resolution deteriorates if the same is supported in the still image recording mode. This is to deal with an increase in image blur correction amount at the expense of resolution. In addition, there is a problem that optical image blur correction cannot be handled.

  The present invention has been made in view of the above-described problems, and image blur correction control capable of performing image blur correction in which a still image has a good image quality without deteriorating the optical performance of the imaging unit. An object is to provide an apparatus, a control method, an imaging apparatus, and an imaging method.

In order to solve the above problems, an image shake correction control apparatus according to the present invention is an image shake correction control apparatus used for an image pickup apparatus that performs image shake correction based on an angular velocity signal obtained by an angular velocity detection sensor provided in the apparatus body. A first angle for generating a first angle signal based on the signal conversion by removing a low frequency component equal to or lower than a predetermined threshold before or after signal conversion of the angular velocity signal. An instantaneous value of the first angle signal generated by the first angle signal generation unit is acquired at the start of opening the shutter of the signal generation unit and the still image capturing unit. A second angle signal generation unit that generates a second angle signal obtained by time-integrating the angular velocity signal while the shutter is open and adding the instantaneous value to the instantaneous value; and when the shutter is closed, angle When the shutter is opened, an angle signal selection unit that selects the second angle signal and the first angle signal or the second angle signal selected by the angle signal selection unit And a target value calculation unit for calculating a control target value for the image blur correction.
According to the present invention, the angle signal selection unit selects the first angle signal generated by the first angle signal generation unit when the shutter of the still image capturing of the imaging device is closed, and the first time signal generated when the shutter is opened. The second angle signal generated by the second angle signal generator is selected, and the target value calculator calculates a control target value for image blur correction based on the selected angle signal. For this reason, when the shutter is closed, the control target value is calculated based on the first angle signal from which the low frequency component equal to or less than the threshold value is removed. For example, for the low frequency movement such as panning or tilting of the imaging apparatus. Thus, it is possible to perform an imaging operation in which the image in the optical axis direction is captured at the center without correcting the image blur.
Further, when the shutter is opened, an instantaneous value of the first angle signal is acquired at the start of opening the shutter, and the angular velocity signal during the time when the shutter is opened from the start of opening the shutter is time-integrated to obtain the instantaneous value. A control target value is calculated based on the second angle signal generated by the addition. Therefore, it is possible to correct the image blur while maintaining the continuity of the control target value for the low-frequency image blur below the threshold value and the high-frequency image blur larger than the threshold value that are generated from the start of opening the shutter.
Therefore, it is possible to satisfactorily correct image blur at the time of still image capturing.

The image shake correction control method of the present invention is an image shake correction control method used for an image pickup apparatus that performs image shake correction based on an angular velocity signal obtained by an angular velocity detection sensor provided in the apparatus body. A first angle signal generating step of generating a first angle signal based on the signal conversion by removing a low frequency component equal to or less than a predetermined threshold before or after signal conversion, and the imaging An instantaneous value of the first angle signal generated by the first angle signal generation unit is acquired at the start of opening of the shutter for capturing a still image of the apparatus, and the shutter is opened from the start of opening of the shutter. A second angle signal generating step for generating a second angle signal obtained by time-integrating the angular velocity signal during the period of time and adding it to the instantaneous value; and when the shutter is closed, the first angle signal A control target value for image blur correction is calculated on the basis of the first angle signal in the generating step, and the image is corrected on the basis of the second angle signal in the second angle signal generating step when the shutter is opened. A control method comprising a target value calculation step for calculating a control target value for shake correction.
Since the present invention is a control method using the image blur correction control device of the present invention, it has the same effects as the image blur correction control device of the present invention.

An imaging device according to the present invention includes an imaging lens that forms an image of a subject on an imaging surface, an angular velocity detection sensor that detects an angular velocity of the apparatus body, and an image shake correction control device according to claim 1 or 2; Image blur correction means for correcting the position of the image on the imaging surface using the control target value calculated by the target value calculation unit of the image blur correction control device is provided.
Since the present invention is an image pickup apparatus using the image blur correction control device of the present invention, it has the same effects as the image blur correction control device of the present invention.

The imaging method of the present invention is an imaging method using the image shake correction control method of the present invention, and forms an object image using the control target value calculated in the target value calculation step. The imaging method includes a correction step of correcting the image position on the image plane of the optical system.
Since the present invention is an imaging method using the image blur correction control method of the present invention, it has the same effects as the image blur correction control method of the present invention.

  According to the image blur correction control device, the control method, the imaging device, and the imaging method of the present invention, with respect to the low-frequency image blur below the threshold and the high-frequency image blur greater than the threshold, which are generated from the start of shutter opening, Since image blur correction can be performed while maintaining the continuity of the control target value, there is an effect that image blur correction can be performed so that a still image has a good image quality without deteriorating the optical performance of the imaging unit. .

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
An image blur correction control apparatus according to a first embodiment of the present invention will be described together with an imaging apparatus using the same.
FIG. 1 is a schematic configuration diagram illustrating a schematic configuration of an imaging apparatus including an image shake correction control apparatus according to the first embodiment of the present invention. FIG. 2 is a control block diagram of the image blur correction control apparatus according to the first embodiment of the present invention.

The camera 1 of the present embodiment is an imaging device that can capture at least a still image, and has, for example, an image blur correction function for camera shake correction. For example, it is suitable as an imaging apparatus such as a digital still camera, a video camera having a still image capturing function, a mobile phone, an information device with a camera such as a PDA (Personal Digital Assistants, personal portable terminal).
As shown in FIG. 1, the schematic configuration of the camera 1 includes an imaging lens unit 3, an imaging device 4, a liquid crystal monitor 6, a release switch 7, an imaging control unit 5, an imaging lens control means 13, a camera housing 2, and an angular velocity sensor 11. And a control target calculation unit 12.

The imaging lens unit 3 forms an image of a subject on an imaging surface, and includes a lens or a lens group housed in a lens barrel (not shown). In this embodiment, the lens barrel is held by an autofocus mechanism (not shown) so as to be movable along the optical axis direction of the imaging system.
In the present embodiment, the imaging lens unit 3 has its lens optical axis 3 a held by the imaging lens driving mechanism 8 so as to be movable in the direction along the imaging surface. Therefore, the image of the subject can be moved on the imaging surface by moving the imaging lens unit 3 along the imaging surface.

  The image pickup device 4 photoelectrically converts an image of light imaged through the image pickup lens unit 3, and has a large number of light receiving sensors arranged in a grid on an image pickup surface having a substantially rectangular shape in plan view. For example, a CCD or a CMOS sensor can be employed.

The liquid crystal monitor 6 is a display unit that displays image data photoelectrically converted by the imaging device 4, an operation screen for operating and setting the camera 1, and the like.
The release switch 7 is an operation switch for opening a shutter (not shown) for capturing a still image, and is connected to the imaging control unit 5. When pressed by the photographer, a shutter release signal 100 is generated.
The release switch 7 sends a control signal for starting an automatic exposure (AE) operation to the imaging control unit 5 by a half-press operation. In this embodiment, the autofocus operation is always performed after the power is turned on. The focus position is detected based on the contrast of the image. In this embodiment, the image sampling frequency for autofocus is set to 10 Hz or more.
The shutter of the camera 1 may be a curtain shutter that is opened and closed by a movable light-shielding curtain provided at any position on the optical axis of the imaging system, or an electronic shutter that temporally controls the photoelectric conversion of the imaging element 4. Good.

The imaging control unit 5 controls the overall operation of the camera 1 and accepts operation inputs from various operation units such as buttons (not shown), dials, and switches. Then, an imaging operation setting, for example, a shooting mode setting, an exposure setting, an autofocus control setting, and the like are performed, and the imaging operation is controlled based on them, and display control on the liquid crystal monitor 6 is performed. Further, when the shutter release signal 100 input from the release switch 7 is detected to open the shutter, the shutter is closed when the shutter is opened for a release time set at a predetermined shutter speed based on the exposure setting. Then, a shutter instruction signal 101 synchronized with the opening and closing of the shutter is sent to the control target value calculation unit 12.
In this embodiment, the shutter instruction signal 101 is a signal for instructing to open the shutter. For example, the signal level is low when the shutter is closed and is high when the shutter is open.
The imaging control unit 5 may be configured by dedicated hardware, or may be realized by a computer including a CPU, a memory, an appropriate input / output interface, and the like.

The imaging lens control means 13 controls the position of the imaging lens unit 3 with respect to the optical axis of the imaging system in order to perform image blur correction control, and includes an imaging lens driving mechanism 8, a servo control circuit 9, and an attitude detection sensor 10. .
In other words, the image pickup apparatus according to the present embodiment is characterized in that the image blur correction unit includes a movement control unit that controls the relative positional relationship of the image pickup lens with respect to the image pickup surface.

The imaging lens drive mechanism 8 is a mechanism for holding the whole or a part of the imaging lens unit 3 so as to be movable relative to the imaging surface in order to move the image of the imaging lens unit 3 on the imaging surface.
In the present embodiment, a mechanism is employed in which the lens optical axis 3a of the imaging lens unit 3 is held so as to be two-dimensionally movable in a direction orthogonal to the optical axis of the imaging system. As a specific drive mechanism, an appropriate mechanism that moves the lens barrel of the imaging lens unit 3 in a biaxial direction orthogonal to the lens optical axis 3a can be employed. For example, a drive mechanism such as a linear motor or an actuator can be employed.
In addition, as an example in the case where a part of the imaging lens unit 3 is held movably, when the imaging lens unit 3 includes a lens group, a mechanism for eccentrically moving a part of the lenses in a direction orthogonal to the lens optical axis 3a. Etc. can be adopted.

The servo control circuit 9 is electrically connected to the imaging lens driving mechanism 8, the posture detection sensor 10, and the control target value calculation unit 12, and drives the imaging lens based on the control target value sent from the control target value calculation unit 12. The drive amount of the mechanism 8 is servo-controlled.
The posture detection sensor 10 is a sensor for detecting and feeding back a deviation of the drive amount of the imaging lens drive mechanism 8 from the control target value. For example, an appropriate non-contact sensor or a mechanical sensor can be adopted.
As the non-contact sensor, for example, an optical sensor, a magnetic sensor, an electrostatic sensor, or the like can be employed as necessary. As the mechanical sensor, for example, a pressure sensor, a strain sensor, or the like can be employed.

  The camera housing 2 includes, for example, an imaging lens unit 3, an imaging device 4, an imaging control unit 5, a control target value calculation unit 12, and the like, and integrally holds a liquid crystal monitor 6 and a release switch 7 on the outer surface, Further, it is a member that the photographer grips at the time of imaging.

The angular velocity sensor 11 is a sensor that detects the angular velocity in the biaxial direction generated in the apparatus main body of the camera 1 in order to detect the angular position of the optical axis of the imaging system. In this embodiment, it is fixed to the camera housing 2 near the imaging lens unit 3. And it is electrically connected to the control target value calculation part 12, and detection output can be sent out as the angular velocity signal 102 now.
The angular velocity signal 102 is composed of a set of two output values corresponding to the angular velocity components in the biaxial directions orthogonal to each other, and is sent out in a readable form by the control target value calculation unit 12 separately for each component. .
As the angular velocity sensor 11, any sensor may be adopted as long as such an angular velocity can be detected. For example, a vibration gyro sensor using Coriolis force can be employed. As a vibrator of the sensor, a vibrator using a piezoelectric element, a MEMS (Micro Electro Mechanical Systems) technique, or the like can be preferably used.

The control target value calculation unit 12 calculates the control target value 103 of the imaging lens control means 13 based on the angular velocity signal 102 from the angular velocity sensor 11 and the shutter instruction signal 101 from the release switch 7, and the servo control circuit 9. Is an image blur correction control device to be sent to the camera.
In the present embodiment, as shown in FIG. 2, it includes an angle converter 20, a high-pass filter 21, a latch 22, an adder 23, a switching circuit 24, and a position calculator 25.
The configuration of the control target value calculation unit 12 may be configured by dedicated hardware for each of these functions, or may be realized by a computer including a CPU, a memory, an appropriate input / output interface, and the like. When the imaging control unit 5 is configured by a computer, it may also be used as a computer configuring the imaging control unit 5.

The angle converter 20 integrates the angular velocity signal 102 from the angular velocity sensor 11 with respect to time, and calculates an angle signal 104 representing an angular position in the three-axis directions from the reference position of the camera 1. For the time integration, an analog integration circuit may be provided, or numerical integration by digital arithmetic processing may be performed by sampling and holding the angular velocity signal.
Thereby, the angle change of the camera 1 in the horizontal direction and the vertical direction can be detected.
The high-pass filter 21 performs a filtering process for removing low frequency components below a predetermined threshold of the angle signal 104 output from the angle converter 20 and outputs the angle signal 105 to the switching circuit 24 and the latch 22.
As the predetermined threshold, the lens optical axis 3a does not move eccentrically with respect to the optical axis of the imaging system when the optical axis of the imaging system is moved by pan movement, tilt movement, or the like. As the center moves, the cut-off frequency is set to be lower than the operating frequency of autofocus. For example, the cutoff frequency is set to 5 Hz.

The latch 22 latches the angle signal 105 that is an output from the high-pass filter 21 in synchronization with the rise of the shutter instruction signal corresponding to the start of shutter opening, and adds the instantaneous value of the angle signal 105 at the start of shutter opening. The signal is sent to the unit 23, and the latch is reset in synchronization with the falling edge of the shutter instruction signal corresponding to the closing of the shutter.
When the addition unit 23 detects the angle signal 105 transmitted in synchronization with the rising edge of the shutter instruction signal 101, the angular velocity signal 102 from the angular velocity sensor 11 is added to the angle signal 105 by time integration, and the angle signal 106 is added. Is generated.
The time integration of the angular velocity signal 102 can be performed using the same means as the angle converter 20.

In response to the shutter instruction signal 101, the switching circuit 24 selects the angle signal 105 generated by the high-pass filter 21 when the shutter is opened, and the angle signal 106 generated by the adder 23 when the shutter is closed, and corrects the angle. The signal 107 is output to the position calculation unit 25.
The position calculation unit 25 calculates the value of the correction angle signal 107 output from the switching circuit 24 as the optical magnification of the imaging lens unit 3 so that the image movement amount on the imaging surface is eliminated. The control target value 103 for controlling the positional relationship of the imaging lens unit 3 with respect to the imaging surface is calculated and sent to the servo control circuit 9.

  Although not particularly illustrated, a known signal processing unit such as an amplifier unit or a noise removing unit may be provided inside and before and after the control target value calculation unit 12 as necessary.

Next, the operation of the camera 1 of the present embodiment will be described focusing on the image blur correction operation.
FIG. 3 is a graph showing an example of an angle signal based on the output of the angular velocity detection sensor of the image blur correction mechanism according to the first embodiment of the present invention. FIG. 4 is a graph showing an example of the angle signal sent to the position calculation unit when the angular velocity signal for generating the angle signal of FIG. 3 is inputted, and the first angle signal. In each graph, the horizontal axis represents time (unit: seconds), and the vertical axis represents the value of the angle signal displayed dimensionlessly.

In the camera 1 of the present embodiment, an autofocus operation is performed while the photographer does not press the shutter but aims at a subject, selects an imaging position, performs framing, and prepares for still image shooting, and is in focus. The moving image is displayed on the liquid crystal monitor 6.
At this time, the camera 1 gripped by the photographer is moved in an arbitrary direction, and the angular velocity sensor 11 sends the angular velocity corresponding to the amount of movement to the angle converter 20 as the angular velocity signal 102. In the angle converter 20, the angular velocity signal 102 is time-integrated to generate an angle signal 104.
For example, it is assumed that an angular displacement as shown in FIG. 3 occurs.

At this time, in the control target value calculation unit 12, the angle signal 104 is filtered by the high-pass filter 21, and in this embodiment, the angle signal 105 in which the low frequency component of 5 Hz or less is cut is generated. This angle signal 105 is shown in FIG.
Since the low-frequency moving component of 5 Hz or less is removed from the angle signal 105, the moving amount is underestimated as compared with the actual moving amount shown in FIG. Therefore, when this angle signal 105 is sent to the position calculation unit 25, an angle correction amount smaller than the actual movement amount is calculated as the control target value 103 and sent to the servo control circuit 9.
Therefore, in this case, the imaging lens unit 3 is servo-controlled by the imaging lens driving mechanism 8 so as to correct image blur at a high frequency higher than 5 Hz, and the angle is relatively small with the reference position of the imaging lens unit 3 as the center. Corresponding movement control is performed. Therefore, although the center of the image moves on the imaging surface, a decrease in contrast and resolution due to image blur is prevented. For this reason, an image with a good autofocus is displayed on the liquid crystal monitor 6.

On the other hand, when the release switch 7 is half-pressed by the photographer, an AE operation is performed by the imaging control unit 5, and the pre-programmed still image imaging aperture and shutter speed are automatically set. When the release switch 7 is fully pressed, the shutter opening signal 100 is input to the imaging control unit 5, the rising edge is synchronized with this signal, and a shutter instruction signal for closing the shutter after a lapse of time according to a predetermined shutter speed. 101 is sent to the control target value calculation unit 12.
At this time, the angle signal 105 is latched and stored by the latch 22 and is sent to the adder 23. Then, from that time, the angular velocity signal 102 is integrated and added to the latched angle signal 105 to generate an angle signal 106.
Then, the angle signal 106 is selected by the switching circuit 24 and sent to the position calculation unit 25 as the correction angle signal 107.
Therefore, as shown in FIG. 4, the correction angle signal 107 coincides with the angle signal 105 while the shutter instruction signal 101 is low, and when the shutter instruction signal 101 becomes high, the angular velocity including the low-frequency component. The time integral value of the signal 102 is added, and the signal gradually deviates from the angle signal 105. That is, while the shutter instruction signal 101 is high, an angle signal corresponding to the angular displacement that changes following the angular velocity including the low frequency component is obtained. Then, the position calculation unit 25 generates a control target value 103 that eliminates the image blur due to the angular displacement of the correction angle signal 107 and sends it to the servo control circuit 9. This operation is continued while the shutter instruction signal 101 is high.
Therefore, when the release switch 7 is fully pressed, the control position of the imaging lens driving mechanism 8 is continuously changed, and the image at the time when the release switch 7 is pressed is stationary on the imaging surface while the shutter is opened. Such image blur correction is performed. As a result, since image blur during the exposure time is prevented, image blur due to camera shake, image flow, and the like are prevented, and still image capturing with good quality is performed.

When the shutter instruction signal 101 returns to low, the correction angle signal 107 is switched to the angle signal 105, and quickly returns to the state before opening the shutter where image blur correction of only high frequency components is performed. Since this change is a direction in which the moving amount of the imaging lens unit 3 is reduced, it is smoothly performed.
Therefore, as shown in FIG. 4, the same operation as described above is repeated even when continuous shooting is performed by opening and closing the shutter at a fixed time pitch.

Next, in order to confirm the effectiveness of the image blur correction according to the present embodiment, a response result in a principle experiment using an actual actuator in which the shutter speed and the angular velocity are changed will be described. In this experimental example, instead of the output of the angular velocity sensor 11, a signal waveform artificially generated using a waveform generator is input to the control target value calculation unit 12.
5, 6, and 7 are graphs showing response waveforms of the first, second, and third experimental examples, respectively, of the image blur correction control apparatus according to the first embodiment of the present invention. In each figure, the horizontal axis represents time (units are 0.1 s / DIV, 0.1 s / DIV, 50 ms / DIV, respectively), and the vertical axis represents the origin position (O) for relative comparison. The output voltage value shifted and appropriately adjusted to the magnification is shown.
Each signal indicates a shutter instruction signal 101, an actual displacement angle signal (angle signal 104), a correction angle signal (control target value 103), and an angle detection output 110 from the top. Here, the angle detection output 110 is obtained by converting the output of the attitude detection sensor 10 into the angle of the lens optical axis 3a.

The first experimental example shown in FIG. 5 is an example in which the shutter speed is 0.078 s and the dominant frequency of the angle signal 104 is 3 Hz.
Since the angle signal 104 contains almost no high-frequency component, there is almost no image blur correction movement when the shutter is closed. However, when the shutter is opened, image blur correction is realized following the low-frequency blur. ing.

The second experimental example shown in FIG. 6 is an example when the shutter speed is 0.095 s and the dominant frequency of the angle signal 104 is 3 Hz.
When the shutter is open, image blur correction is achieved by following low-frequency shake, and when the shutter is closed, image blur correction is performed well following high-frequency shake that is noticeable in some areas. It can be seen that it has been realized.

The third experimental example shown in FIG. 7 is an example when the shutter speed is 0.095 s and the dominant frequency of the angle signal 104 is 3 Hz.
When the shutter is opened, a slightly higher frequency component is included as compared with FIGS. 5 and 6, but it can be seen that image blur correction is also realized following these components.

As described above, the control target value calculation unit 12 of the present embodiment calculates the control target value 103 using the correction angle signal 107 when the shutter is opened. The low-frequency image blur and the high-frequency image blur larger than the threshold value can be corrected while maintaining the continuity of the control target value 103. As a result, when switching from moving image capturing to still image capturing, it is possible to perform image blur correction in which a still image has good image quality.
In addition, while the shutter is open, the imaging lens unit 3 is not moved for image correction in response to low-frequency fluctuations below the threshold value, so that the imaging lens unit 3 is photographed without being greatly displaced from the optical center. Become. Therefore, the deterioration of optical performance is reduced, and good image quality can be obtained.

[Second Embodiment]
An image shake correction control apparatus and an imaging apparatus according to a second embodiment of the present invention will be described.
FIG. 8 is a schematic configuration diagram illustrating a schematic configuration of an imaging apparatus including the image blur correction control device according to the first embodiment of the present invention.

As shown in FIGS. 8 and 2, the camera 15 of the present embodiment includes a control target calculation unit 16 instead of the control target value calculation unit 12 in the camera 1 of the first embodiment, and includes an imaging lens control unit 13. Instead of this, a position correction image processing unit 17 is provided.
That is, the imaging apparatus according to the present embodiment includes an imaging device that photoelectrically converts an image on the imaging surface to generate image data for each pixel, and an image blur correction unit moves the position of the image data on the imaging surface. It is characterized by comprising processing means. Hereinafter, a description will be given focusing on differences from the above embodiment.

The control target calculation unit 16 controls the control target value calculation unit 12 of the first embodiment to control the positional relationship of the imaging lens unit 3 with respect to the imaging surface so that the amount of image movement on the imaging surface is eliminated. Whereas the target value 103 is calculated, the position movement amount of the image data for eliminating the image movement amount on the imaging surface is calculated as a vector amount including the direction on the imaging surface, and the position corrected image is used as the control target value This is sent to the processing unit 17.
The position correction image processing unit 17 is for correcting the position movement amount (position shift amount) of the image due to the shake of the camera 15 by image processing. For example, it is possible to employ image processing in which images are cut out and moved at an appropriate sampling time and then overlapped. Further, when superimposing, appropriate image filter processing may be performed to perform processing such as, for example, reducing sampling noise.

According to the control target calculation unit 16 of the present embodiment, the control target value 108 is calculated using the correction angle signal 107 when the shutter is opened, as in the first embodiment. The image blur correction can be performed while maintaining the continuity of the control target value 108 for the low-frequency image blur below the threshold and the high-frequency image blur larger than the threshold. As a result, when switching from moving image capturing to still image capturing, it is possible to perform image blur correction in which a still image has good image quality.
Further, when the shutter is opened, an image at a position away from the optical center is not cut out and moved to the center for image correction in response to a low-frequency fluctuation below the threshold value, so that good image quality can be obtained.
In addition, since image blur correction is performed by the image processing unit, a mechanism for moving and holding the imaging lens unit 3 for image blur correction can be omitted, and an imaging apparatus having a simple configuration can be configured.

  In the description of the first embodiment described above, the movement control unit that controls the relative positional relationship of the imaging lens with respect to the imaging surface has been described as an example in which the imaging lens is moved with respect to the imaging surface. The imaging element may be moved with the imaging lens fixed.

  In the above description, the high-pass filter 21 is disposed at the subsequent stage of the angle converter 20 so that the low-frequency component is removed and the first angle signal is generated after signal conversion from the angular velocity signal to the angle signal. As described in the example, the arrangement of the angle converter 20 and the high-pass filter 21 may be switched to remove the low frequency component before signal conversion. Further, signal conversion and low frequency component removal may be performed simultaneously.

  Further, the constituent elements described in each of the above embodiments can be appropriately combined and implemented within the scope of the technical idea of the present invention, if technically possible.

Here, a case will be described where the names of the correspondence relationships between the terms of the above embodiments and the terms of the claims are different.
Each of the cameras 1 and 15 is an embodiment of an imaging apparatus. The imaging lens unit 3 is an embodiment of an imaging lens. The angular velocity sensor 11 is an embodiment of an angular velocity detection sensor. The control target value calculation units 12 and 16 are an embodiment of the image blur correction control device. The imaging lens control unit 13 is an embodiment of a movement control unit that is an image blur correction unit. Angle signals 105 and 106 are one embodiment of first and second angle signals, respectively. The angle converter 20 and the high-pass filter 21 constitute an embodiment of the first angle signal generation unit. The latch 22 and the addition unit 23 are an embodiment of a storage unit and an addition unit, respectively, and constitute an embodiment of a second angle signal generation unit. The switching circuit 24 is an embodiment of the angle signal selection unit. The position calculation unit 25 is an embodiment of the target value calculation unit. The position correction image processing unit 17 is an embodiment of image processing means.

1 is a schematic configuration diagram illustrating a schematic configuration of an imaging apparatus including an image shake correction control device according to a first embodiment of the present invention. FIG. 3 is a control block diagram of the image blur correction control device according to the first embodiment of the present invention. 6 is a graph illustrating an example of an angle signal based on an output of an angular velocity detection sensor of the image shake correction mechanism according to the first embodiment of the present invention. It is a graph which shows an example of the angle signal sent to a position calculating part when the angular velocity signal which generate | occur | produces the angle signal of FIG. 3 is input, and a 1st angle signal. It is a graph which shows the response waveform of each 1st experiment example of the image blur correction control apparatus of the 1st Embodiment of this invention. It is a graph which shows the response waveform of each 2nd experiment example of the image blur correction control apparatus of the 1st Embodiment of this invention. It is a graph which shows the response waveform of each 3rd experiment example of the image blur correction control apparatus of the 1st Embodiment of this invention. 1 is a schematic configuration diagram illustrating a schematic configuration of an imaging apparatus including an image shake correction control device according to a first embodiment of the present invention.

Explanation of symbols

1,15 Camera (imaging device)
2 Camera housing 3 Imaging lens unit (imaging lens)
4 Imaging device 5 Imaging control unit 7 Release switch 8 Imaging lens drive mechanism 9 Servo control circuit 10 Attitude detection sensor 11 Angular velocity sensor (angular velocity detection sensor)
12, 16 Control target calculation unit (image blur correction control device)
13 Imaging lens control means (movement control means)
17 Position correction image processing unit (image processing means)
20 Angle converter 21 High-pass filter 22 Latch (storage means)
23 Adder (addition means)
24 switching circuit (angle signal selector)
25 Position calculator (target value calculator)
100 Shutter release signal 101 Shutter instruction signal 102 Angular velocity signals 103 and 108 Control target value 104 Angle signal 105 Angle signal (first angle signal)
106 Angle signal (second angle signal)
107 Angle signal for correction

Claims (6)

An image blur correction control device used for an imaging device that performs image blur correction based on an angular velocity signal obtained by an angular velocity detection sensor provided in the apparatus body,
A first angle signal generating unit that generates a first angle signal based on the signal conversion by removing a low-frequency component equal to or less than a predetermined threshold before or after signal conversion of the angular velocity signal; ,
While the shutter for still image capturing starts to be opened, the instantaneous value of the first angle signal generated by the first angle signal generator is acquired, and the shutter is opened from the start of opening the shutter. A second angle signal generation unit that generates a second angle signal obtained by time-integrating the angular velocity signal and adding to the instantaneous value;
An angle signal selecting unit that selects the first angle signal when the shutter is closed, and the second angle signal when the shutter is opened;
An image blur comprising: a target value calculation unit that calculates a control target value for the image blur correction based on the first angle signal or the second angle signal selected by the angle signal selection unit. Correction control device. An imaging lens that forms an image of a subject on an imaging surface;
An angular velocity detection sensor for detecting the angular velocity of the apparatus body;
The image blur correction control device according to claim 1 or 2,
An image pickup apparatus comprising: an image shake correction unit that corrects a position of an image on the image pickup surface using the control target value calculated by the target value calculation unit of the image shake correction control apparatus.   The imaging apparatus according to claim 2, wherein the image shake correction unit includes a movement control unit that controls a relative positional relationship of the imaging lens with respect to the imaging surface. An image sensor that photoelectrically converts the image of the imaging surface to generate image data for each pixel;
The image shake correcting means comprises image processing means for moving the position of the image data on the imaging surface,
The imaging apparatus according to claim 2, wherein the control target value is an amount for controlling position movement of the image data. An image blur correction control method used for an imaging device that performs image blur correction based on an angular velocity signal obtained by an angular velocity detection sensor provided in the apparatus body,
A first angle signal generation step of removing a low frequency component equal to or lower than a predetermined threshold before or after converting the angular velocity signal into a first angle signal;
An instantaneous value of the first angle signal generated by the first angle signal generation unit is acquired at the start of opening the shutter for still image capturing of the imaging device, and the shutter is opened from the start of opening the shutter. A second angle signal generating step of generating a second angle signal obtained by time-integrating the angular velocity signal while being added and adding to the instantaneous value;
When the shutter is closed, a control target value for the image blur correction is calculated based on the first angle signal generated by the first angle signal generation step;
And a target value calculation step of calculating a control target value of the image blur correction based on the second angle signal in the second angle signal generation step when the shutter is opened. Control method. An imaging method using the image blur correction control method according to claim 5,
An imaging method comprising: a correction step of correcting an image position on an image plane of an imaging optical system that forms a subject image using the control target value calculated in the target value calculation step.

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