JP2020012898A - Interchangeable lens and camera body - Google Patents

Abstract

To provide an interchangeable lens having a further improved target drive position accuracy.SOLUTION: An interchangeable lens 1B is attachable to a camera body 1A. The interchangeable lens 1B includes: an optical system that forms a subject image and includes a shake correction optical system 6 for correcting shake of the subject image; and a reception unit that receives, from the camera body 1A, a motion vector calculated from an image generated by capturing an image of the subject image formed by the optical system and information indicating calculation level of the motion vector of the camera body 1A.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an interchangeable lens and a camera body.

  For example, a technique has been proposed in which motion vector information of an image is detected from a captured image, and the motion vector information is fed back to a calculation of a target drive position of the blur correction lens, thereby improving the vibration reduction performance of optical blur correction. (See Patent Document 1). Conventionally, there has been a demand for improved blur correction performance.

JP-A-10-145662

  An interchangeable lens according to the present invention is an interchangeable lens that can be mounted on a camera body, and is formed by an optical system having a shake correction optical system that forms a subject image and corrects a blur of the subject image, and the optical system. A configuration is provided that includes: a motion vector calculated from an image generated by capturing the subject image; and a receiving unit that receives, from the camera body, information indicating the calculation performance of the motion vector of the camera body.

  Further, the camera body of the present invention is a camera body that can be mounted on an interchangeable lens having a blur correction optical system, and an imaging unit that captures a subject image formed by the interchangeable lens, A motion vector calculation unit that calculates a motion vector from the generated image; a storage unit that stores information indicating the calculation performance of the motion vector of the camera body; and the motion vector used to control the shake correction optical system. And a transmission unit for transmitting the information indicating the calculation performance to the interchangeable lens.

It is sectional drawing which shows a camera system typically. FIG. 3 is a block diagram illustrating a shake correction mechanism included in the camera system. FIG. 4 is a diagram for explaining a calculation timing of motion vector information in a motion vector calculation unit. 5 is a flowchart illustrating the operation of the shake correction mechanism. 5 is a detailed flowchart of a reference value correction step in FIG. 4. (A) is a graph showing a second reference value in the Yaw direction, and (b) is a graph showing a value including the sign of the motion vector in the X direction.

Hereinafter, an interchangeable lens, a camera body, and a camera system according to an embodiment will be described with reference to the drawings and the like. FIG. 1 is a cross-sectional view schematically illustrating the camera system 1. FIG. 2 is a block diagram illustrating a shake correction mechanism 100 showing members, circuits, and the like related to shake correction included in the camera system 1.
In the present embodiment, a three-dimensional orthogonal coordinate system is set as shown in FIG. Specifically, an axis parallel to the optical axis of the interchangeable lens 1B is defined as a Z-axis, intersects the Z-axis in a plane perpendicular to the Z-axis, and a longitudinal direction of the image sensor is defined as an X-axis (in FIG. Direction), and an axis perpendicular to the Z axis and the X axis in a plane perpendicular to the Z axis is defined as the Y axis. The rotation direction about the Z axis is the Roll direction, the rotation direction about the Y axis is the Yaw direction, and the rotation direction about the X axis is the Pitch direction.

(Camera system 1)
The camera system 1 includes a camera body 1A and an interchangeable lens 1B detachably attached to the camera body 1A.

(Camera body 1A)
The camera body 1A includes an imaging element 3, a recording medium 13, a body storage unit 14, a release switch 17, a display unit 18, a shutter 20, a body side transmitting / receiving unit 21 for communication with the interchangeable lens 1B, and a body CPU 2A. Note that the body storage unit 14, the body-side transmitting / receiving unit 21, the image sensor 3, and the body CPU 2A are a part of the shake correction mechanism 100.

A subject image formed by the photographing lens 16 of the interchangeable lens 1 </ b> B having the zoom lens 4, the focus lens 5, the shake correction lens 6, and the diaphragm 10 is captured by the image sensor 3. The imaging element 3 is composed of a plurality of pixels having a photoelectric conversion unit that photoelectrically converts light from a subject, and outputs an image signal (hereinafter, referred to as imaging) based on a signal that is photoelectrically converted and output. The imaging element 3 is configured by a light receiving element such as a CCD or a CMOS. In a signal processing unit 40 described later included in the body CPU 2A, various image processing is performed on the image signal output from the image sensor 3 to generate image data.
Output of an image signal by the image sensor 3 and generation of image data by the signal processing unit 40 are repeated at a predetermined timing, and an image based on the generated image data is continuously displayed on the display unit as a live view image. You.

  The recording medium 13 is a medium (memory card) for recording captured image data, and an SD card, a CF card, or the like is used.

The body storage unit 14 is a memory such as an EEPROM, for example, and stores information on the interchangeable lens 1B received from the interchangeable lens 1B. The information on the interchangeable lens 1B includes a focal length, a photographing distance, an open F value, and the like of the interchangeable lens 1B. The body storage unit 14 also stores the calculation level of the camera body 1A, the calculated motion vector, and the detection delay time of the motion vector. The calculation level, which will be described later, is a value determined in advance according to the calculation performance and calculation accuracy of the camera body 1A, and is information indicating the calculation performance of the motion vector. The calculation level is stored in the body storage unit 14. The calculation level is a level determined by the calculation performance and calculation accuracy of calculating a motion vector of an image. The calculation level is a value indicating the calculation performance determined by the calculation performance and calculation accuracy of the camera body 1A for calculating the motion vector. The higher the calculation level, that is, the higher the calculation performance and calculation accuracy, the higher the accuracy and reliability of the calculated motion vector (the higher the calculation performance). The calculation level stored in the body storage unit 14, the calculated motion vector, and the detection delay time of the motion vector are read by the body CPU 2A and output to the lens CPU 2B via the body side transmission / reception unit 21 and the lens side transmission / reception unit 22. You.
Here, the calculation level of the camera body 1A for the motion vector is determined by the performance of the camera body 1A such as the performance of the body CPU 2A for calculating the motion vector and the number of pixels of the image sensor 3, for example. The operation level is determined by one of numerical values such as operation level 0 (lowest level), 1, 2, 3, 4, 5, 6, 7 (highest level).

  The release switch 17 is a member for instructing the camera system 1 to shoot an image for recording. The image data that has been captured and generated in accordance with the instruction of the release switch 17 is recorded on the recording medium 13 as a captured image.

  The display unit 18 is provided on the back of the camera body 1A, and displays images (playback images, live view images), information (menus) related to operations, and the like. A liquid crystal display or an organic EL display is used. Further, the display unit 18 may include a touch panel, and may be configured to input a user operation.

  The shutter 20 is disposed on the light incident side (imaging surface side) of the imaging element 3. The shutter 20 controls the exposure time of the image sensor 3 by causing the shutter curtain to run in response to a shooting instruction from the release switch 17.

(Body CPU 2A)
The body CPU 2A is a central processing unit that controls the entire camera system 1.
The information is read from the body storage unit 14 and the focus is detected. Focus detection is to detect the position of the focus lens 5 where the position of the subject image formed by the photographing lens 16 of the interchangeable lens 1B and the imaging surface of the imaging element 3 match (focus). The imaging element 3 has pixels for outputting an image signal for generating image data and pixels for outputting a focus detection signal used for focus detection, and the body CPU 2A has a well-known pupil division type using the focus detection signal. Focus detection by a phase difference method or focus detection by a well-known contrast method using an image signal is performed. As shown in FIG. 2, the body CPU 2A includes a signal processing unit 40 and a motion vector calculation unit 41.

(Signal processing unit 40)
The signal processing unit 40 performs A / D conversion, noise processing, and various types of image processing on the image signal output from the image sensor 3 to generate image data.

(Motion vector calculator 41)
The motion vector calculator 41 calculates motion vector information including a motion vector and a detection delay time of the motion vector. The motion vector is calculated from the image data generated by the signal processing unit 40, indicates a displacement (moving direction, moving amount) of the subject image over time, and indicates directions in the X-axis direction, the Y-axis direction, and the Roll direction. It is represented by a signed size. Although the detection delay time of the motion vector will be described in detail later, the time when the image sensor 3 generates the image signal that is the basis of the image data for which the motion vector is obtained, and the time when the body-side transmitting / receiving unit 21 transmits the motion vector information to the interchangeable lens 1B Is the time difference from the time of transmission to
Specifically, the motion vector calculation unit 41 obtains a motion vector as described below. The positions of the bright spots set in the image are compared at two different times with two images generated from the subject image captured by the image sensor 3, and based on the change in the position of the bright spot, the moving direction of the bright spot and the moving direction of the bright spot are compared. Detect the amount of motion. In addition to comparing the positions of the luminescent spots, a motion vector may be obtained by pattern matching of an image or the like.
The motion vector may be detected from one image, or may be calculated from three or more images.

(Motion vector detection delay time calculation method)
FIG. 3 is a diagram illustrating an example of a timing of calculating a motion vector in the motion vector calculation unit 41, and illustrates a state in which the image sensor 3 continuously captures images. FIG. 3 shows a state of imaging by the CMOS as the image sensor 3, and the image signal is read for each row, so that the read time of the first row is earlier and the read time of the last row is later. n-2, n-1, n, n + 1, and n + 2 are numbers corresponding to a plurality of image signals output by the image sensor 3. For example, the n-th image signal is an image signal that is output after starting imaging at time t4 and ending imaging at time t7.
The motion vector calculation unit 41 is generated from an image generated from the (n-1) th image signal and an nth image signal captured at a time later than the time at which the (n-1) th image is captured. Calculate the motion vector from the image.

In the figure, time t1 is the time when the imaging of the (n-1) th image signal is started.
The time t2 is an intermediate time between the time when the imaging of the (n-1) th image signal is started and the time when the imaging is ended, and is a representative time of the generation of the (n-1) th image signal.
Time t4 is a time when the imaging of the n-th image signal is started.
The time t5 is an intermediate time between the time when the imaging of the n-th image signal is started and the time when the imaging is completed, and is a representative time for generating the n-th image signal.
The pulse shown in the lower part of FIG. 3 is a diagram showing the timing of communication from the camera body 1A to the interchangeable lens 1B. At time t6, the motion vector information transmitted from the body side transmitting / receiving section 21 to the lens side transmitting / receiving section 22 is motion vector information calculated based on the n-1 image signal and the n image signal. The generation time of the information is set to a time t3 which is intermediate between t5 (representative time for generating the n-th image) and t2 (representative time for generating the (n-1) th image). Between the time t6 at which the motion vector was transmitted and the time t3 at which the motion vector occurred, a detection delay time of t6-t3 occurs, and this time is defined as a motion vector detection delay time.
The motion vector and the detection delay time of the motion vector are transmitted as motion vector information from the body-side transmission / reception unit 21 to the lens-side transmission / reception unit 22 at time t6 shown in the drawing.
When communication between the camera body 1A and the interchangeable lens 1B is repeatedly performed every 33 ms, an image signal is output from the image sensor 3 every 30 fps, that is, every 33 ms, and a motion vector is calculated every 33 ms. For each communication between the body 1A and the interchangeable lens 1B, a motion vector and a motion vector detection delay time (motion vector information) are transmitted.

  In the calculation of the motion vector, the interval between the representative times of two image signals from which two images from which motion vector information is calculated is calculated according to the focal length of the interchangeable lens 1B periodically received from the interchangeable lens 1B. May be changed. That is, the image capturing interval (frame rate) may be changed, or the two images to be calculated may be skipped one by one (for example, a motion vector is calculated using n-1 and n + 1). The shorter the focal length of the interchangeable lens 1B, the longer the interval between the representative times of generation of two image signals may be. This is because if the focal length is short, the amount of movement of the subject in the image is small, that is, the motion vector is small. As a result, the accuracy of detecting motion vector information can be improved.

(Body side transceiver 21)
When the interchangeable lens 1B is mounted on the camera body 1A, the body-side transmitting / receiving section 21 contacts the lens-side transmitting / receiving section 22. Thus, signals can be transmitted and received between the camera body 1A and the interchangeable lens 1B. The body side transmitting / receiving section 21 receives lens information including the focal length information of the interchangeable lens 1B from the lens side transmitting / receiving section 22. The body-side transmitting / receiving unit 21 also stores the motion vector information (the motion vector and the detection delay time of the motion vector) calculated by the motion vector calculating unit 41 and the calculation level of the motion vector (or information indicating the calculation level or calculation performance). The transmitted camera information is transmitted to the lens-side transmitting / receiving unit 22.

(Interchangeable lens 1B)
Next, the interchangeable lens 1B will be described with reference to FIGS.
The interchangeable lens 1B includes a photographing lens 16 having a zoom lens 4, a focus lens 5, and a blur correction lens 6, a zoom lens drive mechanism 7, a focus lens drive mechanism 8, a blur correction lens drive mechanism 9, an aperture 10, and an aperture drive mechanism 11. , An angular velocity sensor 12, a blur correction lens position detection unit 23 (FIG. 2), a focal length detection unit 24 (FIG. 2), a lens CPU 2B, a lens storage unit 45 (FIG. 2), and a lens side transmission / reception unit 22.
Note that the zoom lens 4, the blur correction lens 6, the zoom lens drive mechanism 7, the blur correction lens drive mechanism 9, the angular velocity sensor 12, the blur correction lens position detection unit 23, the focal length detection unit 24, the lens CPU 2B, the lens storage unit 45, The lens-side transmitting / receiving unit 22 is a part of the shake correction mechanism 100 shown in FIG.

The zoom lens 4 is a lens group that is driven by, for example, a zoom lens driving mechanism 7 that is a zoom ring and moves along the optical axis direction to continuously change the focal length of the interchangeable lens 1B. Note that the zoom lens driving mechanism 7 may be configured to detect rotation of the zoom ring or the like and electrically drive the zoom lens based on a signal from the lens CPU 2B. Alternatively, electric zooming may be performed by a button operation.
The focal length detector 24 detects the zoom position, which is the position of the zoom lens 4 of the interchangeable lens 1B, and calculates the focal length of the interchangeable lens 1B.

  The focus lens 5 is driven by the focus lens drive mechanism 8 and moves in the optical axis direction to focus (focus the subject image formed by the photographing lens 16 of the interchangeable lens 1B on the imaging surface of the imaging element 3). ) Lens group.

  The blur correction lens 6 is a lens group that is driven by a blur correction lens driving mechanism 9 such as a VCM (voice coil motor) to optically correct blur, and is movable on a plane intersecting the optical axis.

  The diaphragm 10 is driven by a diaphragm driving mechanism 11 to limit the light flux of light passing through the photographing lens 16 and control the amount of light incident on the image sensor 3.

  The angular velocity sensor 12 is a sensor that detects an angular velocity of a shake generated in the interchangeable lens 1B. A sensor such as a vibrating gyroscope that detects angular velocities around the X axis (Pitch) and around the Y axis (Yaw). Note that the angular velocity sensor 12 may also detect an angular velocity around the Z axis (Roll).

  The lens CPU 2B calculates the drive amount of the lenses such as the focus lens 5 and the blur correction lens 6. Then, the drive amount is instructed to the focus lens drive mechanism 8 and the blur correction lens drive mechanism 9 to move the focus lens 5 and the blur correction lens 6.

  The lens CPU 2B includes an amplification unit 31, a first A / D conversion unit 32, a second A / D conversion unit 33, a reference value calculation unit 34, a target position calculation unit 36 including an integration unit therein, a center bias calculation unit 37, A reference value correction unit 50, a drive amount calculation unit 39, and a subtraction unit 43 are provided.

  The amplification unit 31 amplifies the output of the angular velocity sensor 12.

  The first A / D converter 32 performs A / D conversion on the output of the amplifier 31.

The reference value calculator 34 amplifies the angular velocity obtained from the angular velocity sensor 12 by the amplifier 31 and calculates a reference value of the angular velocity from the angular velocity A / D converted by the first A / D converter 32. The reference value of the angular velocity is a value serving as a reference of the angular velocity output from the angular velocity sensor 12 in a state where vibration is not applied to the camera system 1 (for example, when the camera system 1 is stationary). Since the reference value of the angular velocity changes due to temperature characteristics, drift characteristics immediately after startup, and the like, the reference value cannot be determined at the time of factory shipment. Therefore, when the camera system 1 is used, it is necessary to obtain a reference value of the angular velocity from a signal output by actually driving the angular velocity sensor.
Here, if the reference value of the angular velocity cannot be obtained accurately, a vibration component cannot be extracted from the angular velocity signal, so that blur correction cannot be performed effectively. That is, if the reference value is not accurate, the blur correction cannot be effectively performed even if the blur correction lens 6 is driven. For example, when the shutter speed is low, the captured image may be blurred even when the blur correction lens 6 is driven.
In addition, as will be described later in detail, in the present embodiment, in order to more accurately calculate the reference value of the angular velocity, the reference value is corrected using the motion vector information received from the camera body 1A.
As is well known, the reference value calculation unit 34 obtains an initial reference value (first reference value, reference value before correction) by passing the output of the angular velocity sensor 12 through a low-pass filter that reduces a predetermined high-frequency component.

  The subtractor 43 subtracts the first reference value calculated by the reference value calculator 34 from the output (angular velocity) of the first A / D converter 32.

  The target position calculator 36 calculates the target position of the blur correction lens 6 from the angular velocity output from the angular velocity sensor 12 after the subtraction of the reference value by the subtractor 43.

The center bias calculator 37 calculates a correction amount (referred to as a bias amount) of the position of the blur correction lens 6 calculated based on the target position of the blur correction lens 6 calculated by the target position calculator 36. A centering bias process for subtracting from the target position to approach the optical axis of the interchangeable lens 1B is performed, the target position of the blur correction lens 6 in which the bias amount has been corrected is calculated, and the target position is corrected. That is, the actual movement position of the blur correction lens 6 is closer to the optical axis of the interchangeable lens 1B by the bias amount than the target position calculated based on the output of the angular velocity sensor 12.
By performing the centering bias processing in this way, it is possible to effectively prevent the blur correction lens 6 from colliding with a physical movement limit (hard limit) such as a holding frame of the blur correction lens.

  The drive amount calculating section 39 uses the second A / D converter 33 to convert the target position of the blur correction lens 6 in which the bias amount calculated by the center bias calculating section 37 has been corrected and the signal detected by the blur correction lens position detecting section 23. A drive amount for driving the blur correction lens 6 by the blur correction lens driving mechanism 9 is calculated from the current position of the blur correction lens 6 obtained from the A / D converted value.

(Lens side transmitting / receiving unit 22)
When the interchangeable lens 1B is mounted on the camera body 1A as described above, the lens-side transmitting / receiving section 22 comes into contact with the body-side transmitting / receiving section 21 to enable transmission and reception between the camera body 1A and the interchangeable lens 1B.
The lens-side transmitting / receiving section 22 transmits the focal length information detected by the focal length detecting section 24 to the body-side transmitting / receiving section 21.
The lens-side transmitting / receiving unit 22 is determined for each body by the motion-vector information (the amount / direction of the motion vector and the detection delay time of the motion vector) calculated by the motion-vector calculating unit 41 from the body-side transmitting / receiving unit 21. An operation level of the motion vector (or information indicating the operation level or calculation performance) is received.
Note that the motion vector information is not always sent as described above, and the communication interval between the camera body 1A and the interchangeable lens 1B is smaller than the motion vector calculation interval by the motion vector calculator 41. In some cases, information indicating that a motion vector is being calculated is sent instead of the amount of the motion vector or the detection delay time of the motion vector.

(Lens storage unit 45)
The lens storage unit 45 stores a minimum focal length, which is the shortest focal length for performing reference value correction using a motion vector, for each calculation level received by the lens-side transmitting / receiving unit 22. Table 1 below shows an example of the stored contents.
Table 1 shows that when the operation level of the highest performance is 7, the reference value is corrected using the motion vector at all focal lengths where the focal length of the photographing lens is longer than 10 mm, and when the operation level is 0, This indicates that the reference value is corrected using the motion vector only when the focal length of the taking lens is longer than 135 mm.

The reason why the lower limit value (minimum focal length) of the focal length for correcting the reference value changes depending on the calculation level is that the reliability of the motion vector information depends on the calculation level of the camera body 1A.
Generally, when a shake occurs in the interchangeable lens 1B, the amount of change in the image appearing on the image plane (the amount of movement due to the shake) depends on the focal length of the taking lens. When a certain amount of shake occurs, the smaller the focal length of the photographing lens, the smaller the amount of change in the image on the image plane, and the longer the focal length of the photographing lens, the larger the amount of change in the image appearing in the image. That is, the shorter the focal length of the photographing lens, the more difficult it is to detect a motion vector. Therefore, it can be said that a motion vector calculated by a camera body having a low calculation level has low reliability when the focal length of the photographing lens is short.
When the calculation level is high (high performance), the reliability of the motion vector is high even when the focal length is short, so that the reference value can be corrected using the motion vector even when the focal length is short. On the other hand, when the calculation level is low (the performance is poor), the reliability of the motion vector is low when the focal length is short. Therefore, when the reference value is corrected using the motion vector when the focal length is short, the anti-vibration performance becomes poor. Conversely, it may deteriorate.

(Reference value correction unit 50)
The reference value correction unit 50 corrects the initial reference value (first reference value) calculated by the reference value calculation unit as needed using the motion vector information, and determines the determination unit 44, the center bias removal unit 38, and the reference value correction amount. An arithmetic unit 35 and a subtraction / addition unit 42 are provided.

(Judgment unit 44)
The determination unit 44 compares the focal length of the interchangeable lens 1B with the minimum focal length corresponding to the calculation level received from the camera body 1A.
If the focal length of the photographing lens is shorter than the minimum focal length corresponding to the calculation level (wide side), it is determined that the reference value is not corrected (reference value correction amount is not calculated). In this case, the motion vector information is not sent to the center bias removing unit 38.
If the focal length of the interchangeable lens 1B is longer than the minimum focal length corresponding to the calculation level (tele side), it is determined that the initial reference value is to be corrected as needed (a reference value correction amount is calculated). In this case, the motion vector information to the center bias removing unit 38 is sent.
It is more preferable that the determination unit 44 obtains a focal length when an image in which a motion vector is calculated is captured using the detection delay time of the motion vector. That is, using the detection delay time received from the camera body 1A, the focal length of the photographing lens at the time of performing the imaging that is the basis of the motion vector calculation is obtained, and the focal length is calculated based on the focal length and the calculation level received from the camera body 1A. It is good to compare with the minimum focal length. This allows more accurate control.

  Further, even when the focal length of the interchangeable lens 1B is shorter than the minimum focal length corresponding to the calculation level, if the value of the motion vector is larger than a predetermined value, the reference value may be corrected.

  In the present embodiment, the determination unit 44 is arranged between the lens-side transmitting / receiving unit 22 and the center bias removing unit 38. However, the present invention is not limited to this. It may be provided at any place.

  In the following description, correction of the reference value in the X direction will be described. The value of the motion vector in the X direction is defined as a motion vector amount X. The correction of the reference value in the Y direction is the same as that in the X direction. In this embodiment, the Roll direction information of the motion vector information is not received.

(Center bias removing unit 38)
The center bias removing unit 38 obtains a motion vector amount X detected when the center bias calculating unit 37 does not perform the centering bias processing.
As described above, since the centering bias processing is performed by the center bias calculator 37, the actual movement position of the blur correction lens 6 is photographed by the bias amount more than the target position calculated based on the output of the angular velocity sensor 12. The position is close to the optical axis of the lens. Therefore, a large value is detected as the motion vector value X as compared with the case where the center bias processing is not performed. In other words, since the blur correction lens 6 is not driven to the target correction position, a shake component remains due to insufficient driving, and the motion vector value X increases corresponding to the shortage. For this reason, the center bias removing unit 38 calculates a motion vector amount which is extra detected as compared with the case where the center bias processing is not performed, based on the center bias amount. The extra motion vector detected is referred to as a motion vector correction amount. Then, the motion vector correction amount is subtracted from the motion vector X received from the camera body 1A. As the bias amount for calculating the motion vector correction amount, the bias amount at the detection time of the motion vector obtained from the detection delay time of the motion vector received from the camera body 1A is used.

(Reference value correction amount calculation unit 35)
The reference value correction amount calculating section 35 corrects the reference value calculated by the reference value calculating section 34 based on the motion vector amount X from which the motion vector correction amount has been removed by the center bias removing section 38. Is calculated.
In the present embodiment, in order to simplify the processing, only the sign of the motion vector amount X is determined. When the motion vector amount X is in the minus direction, a certain fixed amount is used as the reference value correction amount. Is used as a reference value correction amount.

However, the reference value correction amount may be changed according to the minimum focal length corresponding to the calculation level, the focal length of the interchangeable lens 1B, and the magnitude of the motion vector.
When the focal length of the interchangeable lens 1B is equal to or longer than the minimum focal length corresponding to the calculation level (telephoto), the reference value correction amount may be a value inversely proportional to the focal length of the interchangeable lens 1B. This is because the magnitude of the detected motion vector increases as the focal length of the interchangeable lens 1B increases.

  The subtraction / addition unit 42 corrects the reference value (first reference value) with the reference value correction amount calculated by the reference value calculation unit 34 to obtain a corrected reference value (second reference value).

(Operation of Image Stabilization Mechanism 100)
Next, the operation of the shake correction mechanism 100 will be described. FIG. 4 is a flowchart of a shake correction process showing the operation of the shake correction mechanism 100.

  In the following description, the operation performed by the lens CPU 2B of the interchangeable lens 1B as a part of the shake correction mechanism 100 will be described as the operation performed by the interchangeable lens 1B as a part of the shake correction mechanism 100 (the flow on the left side of FIG. 4), and the blur correction will be described. An operation performed by the body CPU of the camera body 1A as a part of the mechanism 100 will be described as an operation performed by the camera body 1A (flow on the right side in FIG. 4).

(Interchangeable lens 1B side)
Step 101: When the interchangeable lens 1B has a blur correction function (step 101, YES), the flow proceeds to step 102.
If the interchangeable lens 1B does not have the blur correction function (step 101, NO), the lens-side blur correction processing ends.

  Step 102: The interchangeable lens 1B transmits a signal indicating that the interchangeable lens 1B has a blur correction function from the lens side transmitting / receiving unit 22 to the camera body 1A, and proceeds to step 103.

Step 103: When the interchangeable lens 1B has the reference value correcting function (YES in Step 103), the process proceeds to Step 104.
If the interchangeable lens 1B does not have the reference value correction function (step 103, NO), the process proceeds to step 115.

  Step 104: The interchangeable lens 1B transmits a signal indicating that the interchangeable lens 1B has the reference value correction function to the camera body 1A, and proceeds to step 105.

  Step 105: In the interchangeable lens 1B, the output of the angular velocity sensor 12 is amplified by the amplifier 31 and A / D converted by the first A / D converter 32, and the process proceeds to Step 106.

  Step 106: The interchangeable lens 1B calculates the initial reference value (first reference value) of the angular velocity in the reference value calculation section 34 based on the signal after the A / D conversion of the output of the angular velocity sensor 12, and step 107 Proceed to.

  As described above, since the reference value of the angular velocity changes due to the temperature characteristic, the drift characteristic immediately after startup, and the like, for example, the stationary output at the time of factory shipment cannot be used as the reference value. For this reason, the reference value calculation unit 34 calculates the reference value of the angular velocity while the shake correction process is being performed.

  In the present embodiment, reference value calculation by low-pass filter processing (LPF processing) is used. The cutoff frequency fc of the LPF processing is generally set to a low frequency of about 0.1 [Hz]. This is because camera shake is dominated by frequencies of about 1 to 10 [Hz]. If the cutoff frequency fc is 0.1 [Hz], the effect on the camera shake component is small, and good shake correction can be performed.

  However, at the time of actual photographing, a low-frequency movement such as an extremely small camera shake or a fine adjustment of the composition (a level at which panning cannot be detected) is added, so that the reference value calculation result may have an error. Further, when the cutoff frequency fc is low (the time constant is large) and the error once increases, it takes time to converge to a true value. The reference value correction is for correcting fluctuations and errors of the reference value.

(Camera body 1A side)
Step 201: When the camera body 1A receives a signal indicating that the interchangeable lens 1B has a blur correction function in the body-side transmitting / receiving section 21, the process proceeds to step 202 (step 201, YES).
When the camera-side transmission / reception unit 21 does not receive a signal indicating that the interchangeable lens 1B has the shake correction function, the camera body 1A ends the body-side shake correction processing.

Step 202: When the camera body 1A receives a signal that the interchangeable lens 1B has the reference value correcting function in the body side transmitting / receiving section 21 (step 202, YES), the process proceeds to step 203.
When the body-side transmitting / receiving section 21 does not receive a signal indicating that the interchangeable lens 1B has the reference value correcting function, the camera body 1A ends the body-side blur correction processing.

Step 203: If the motion vector can be calculated, the camera body 1A proceeds to step 204.
When the motion vector cannot be calculated, the camera body 1A ends the camera-body shake correction processing.

  Step 204: The camera body 1A calculates the motion vector information as described above.

  Step 205: The camera body 1A transmits the motion vector information (the motion vector and the detection delay time of the motion vector) and the calculation level to the interchangeable lens 1B from the body side transmitting / receiving unit 21.

(Interchangeable lens 1B side)
Step 107: When the interchangeable lens 1B receives the motion vector information and the calculation level in the lens side transmitting / receiving unit 22 (YES in step 107), the process proceeds to step 108.

  The timing of communication from the camera body 1A to the interchangeable lens 1B is, for example, every 33 ms, but the timing at which the motion vector information is obtained may be once every 66 ms as described above. Then, the motion vector information is not included once every two times, and a signal indicating that the motion vector information is being calculated is transmitted from the camera body 1A to the interchangeable lens 1B.

When the calculated motion vector information and the calculated level are not transmitted from the body-side transmitting / receiving unit 21 and a signal indicating that such a calculation is being performed is transmitted from the body-side transmitting / receiving unit 21 (NO in step 107), The process proceeds to step 110 without correcting the reference value.
Also, the control cycle of the optical blur correction is, for example, 1 ms, which is shorter than the update cycle of the motion vector, so that the motion vector may not be received in some cases (NO in step 107). Also in this case, the process proceeds to step 110 without correcting the reference value.

Step 108: In the interchangeable lens 1B, based on the data stored in the lens storage unit 45, the current focal length of the interchangeable lens 1B is determined by the determination unit 44 to be smaller than the minimum focal length corresponding to each calculation level. Is determined to be a long (tele side) focal length.
When the focal length of the interchangeable lens 1B is equal to or longer than the minimum focal length corresponding to the received calculation level (YES in Step 108), the process proceeds to Step 109.
If the focal length of the interchangeable lens 1B is smaller than the minimum focal length corresponding to the received calculation level (NO in Step 108), the process proceeds to Step 110 without performing the reference value correction.

Step 109: If the focal length of the interchangeable lens 1B is equal to or longer than the minimum focal length corresponding to the received calculation level (the focal length is long) (step 108, YES), the reference value is corrected. Actually, in the reference value correction, the second reference value is calculated by correcting the first reference value calculated before the received delay time by the reference value correction amount based on the received motion vector. This reference value correction step 109 will be described later with reference to FIG.
If the focal length of the interchangeable lens 1B is smaller than the minimum focal length corresponding to the received calculation level (step 108, NO), the process proceeds to step 110 without performing the reference value correction.

  Step 110: The interchangeable lens 1B integrates the output of the angular velocity sensor 12 after subtracting the reference value, and based on information such as a focal length, a subject distance, and a ratio of a displacement amount of the subject image to a unit shift amount of the blur correction lens. The target position of the shake correction lens 6 is calculated, and the process proceeds to step 111.

Step 111: In order to prevent the blur correction lens 6 from reaching the movable end, the interchangeable lens 1B performs center bias processing on the target position of the blur correction lens 6 calculated in step 110, and proceeds to step 112.
There are various methods of center bias processing, such as a method of setting a bias amount according to target position information, a high-pass filter processing (HPF processing), an incomplete integration processing (at step 110), and the like. It doesn't matter.

  Step 112: The interchangeable lens 1B calculates the lens drive amount in the drive amount calculating section 39 from the target position information considering the center bias component and the blur correction lens position information, and proceeds to step 113.

  Step 113: The interchangeable lens 1B drives the blur correcting lens 6 to the target position after the center bias processing by the blur correcting lens driving mechanism 9, and the process proceeds to S114.

Step 114: The interchangeable lens 1B proceeds to step 103 when the blur correction function is not turned off (step 114, NO).
When the shake correction function is OFF (step 114, YES), the interchangeable lens 1B ends the lens-side shake correction processing.

  Step 115: The interchangeable lens 1B having no reference value correction function amplifies the output of the angular velocity sensor 12 by the amplifying unit 31 and performs A / D conversion by the first A / D converting unit 32, as in step 105. Proceed to 116.

  Step 116: In the interchangeable lens 1B, similarly to step 106, the reference value calculation unit 34 calculates the reference value of the angular velocity in the calculation based on the signal after the A / D conversion of the output of the angular velocity sensor 12, Proceeding to 110, the blur correction processing of step 110 and thereafter is performed.

(Camera body 1A side)
Step 206: If the camera shake correction function is not turned off (step 206, NO), the camera body 1A returns to step 204 and repeats the operations from step 204 on.
If the blur correction function is OFF (step 206, YES), the camera body 1A ends the body-side blur correction processing.

FIG. 5 is a detailed flowchart of the reference value correcting step 109 in FIG.
Step 301: The interchangeable lens 1B converts the amount of bias of the blur correction lens 6 into a size on the image plane, and calculates a motion vector correction amount indicated by the number of pixels of the image sensor 3. That is, the magnitude of the extra motion vector generated by the center bias processing of the blur correction lens is calculated. The conversion of the size on the image plane is calculated by the following formula based on the focal length, the imaging magnification, the resolution information of the motion vector, and the bias amount.

Bias_MV = Bias_θ * f * (1 + β) / MV_pitch
Bias_MV: Motion vector correction amount Bias_θ: Bias amount (differential value)
f: focal length β: shooting magnification MV_pitch: motion vector pitch size (pixel interval: resolution information of motion vector)

  In addition, there is a difference between the time at which the motion vector is generated and the time at which the motion vector information is received by the interchangeable lens 1B. It is preferred to use. By using the bias amount calculated from the motion vector detected from the image data captured at the previous time for the detection delay time received from the camera body 1A, the motion vector correction amount can be calculated more accurately.

  Step 302: The interchangeable lens 1B calculates a corrected motion vector (MV) by subtracting the motion vector correction amount calculated in step 301 from the motion vector received from the camera body 1A in the center bias removing unit 38, and proceeds to step 303. .

Step 303: In the interchangeable lens 1B, the reference value correction amount calculation unit 35 sets a correction amount (reference value correction amount) of the reference value based on the motion vector based on the corrected motion vector (MV), and proceeds to step 304. . The reference value correction amount is set based on the following concept.
That is, when the corrected motion vector (MV) is positive, a reference value correction amount that is a negative constant is set. If the corrected motion vector (MV) is negative, a reference value correction amount that is a positive constant is set. When the corrected motion vector (MV) is 0, the reference value correction is 0.

MV> 0: ω0_comp = − (ω0_comp_def)
MV <0: ω0_comp = + (ω0_comp_def)
MV = 0: ω0_comp = 0

ω0_comp: reference value correction amount ω0_comp_def: reference value correction constant The reference value correction constant is a constant determined by the focal length of the taking lens. The focal length is taken into consideration because the amount of movement of the image plane changes by multiplying the focal length by the angular velocity.

Step 304: The interchangeable lens 1B obtains the corrected second reference value by adding or subtracting the ω0_comp calculated in step 303 from the first reference value calculated in step 106 in the subtraction addition section 42.
Note that the corrected second reference value is used as a first reference value calculated in step 106 when returning from step 114 to step 103 in a subsequent step (see FIG. 4). That is, the first reference value is obtained in step 106, and the second reference value calculated by correcting the first reference value in step 109 is returned from step 114 to step 103, and a new second reference value is obtained in the process of step 106 again. Treated as one reference value.

  FIG. 6A is a graph showing a second reference value in the Yaw direction. The dotted line in the figure indicates the first reference value (reference value subjected to the low-pass filter processing) when the reference value is not corrected according to the present embodiment, and the solid line in the figure indicates that the first reference value is periodically changed according to the present embodiment. Shows the second reference value that has been repeatedly corrected.

FIG. 6B is a graph showing the time when a motion vector in the X direction is detected and the direction of the motion vector MV.
For example, when the MV is in the plus direction, as at time T1 in FIG. 6B, the first reference value is corrected to the minus of the reference value correction amount constant as shown in FIG. 6A, and the second reference value is calculated. I do. Thereafter, until the time T3, the second reference value changes according to the value calculated by the reference value calculation unit 34.
When the MV calculated at the time T3 is in the plus direction, the reference value (second reference value) calculated at the time T1 that has changed until the time T3 is corrected to be minus by the reference value correction amount constant.
After that, between the time when the MV is calculated and the time when the next MV is calculated, the once calculated second reference value changes according to the value calculated by the reference value calculation unit 34.
When the MV is calculated in the plus direction, the first reference value (or the reference value in which the second reference value once calculated has changed with time) is corrected to be minus by the reference value correction amount constant, but at time T22 in the figure. When the MV is calculated in the negative direction as in T25 or T25, the first reference value is corrected to the reference value correction amount constant plus.

Note that the reference value correction amount or the reference value correction constant may be changed according to the focal length of the interchangeable lens 1B.
As described above, when the motion vector is appropriately corrected and used for the reference value, the reference value approaches the true value, and the accuracy of the blur correction is improved.

As described above, in the interchangeable lens of the present embodiment, since the motion vector and the information indicating the operation level of the motion vector are received from the camera body 1A, the accuracy of blur correction can be improved.
In addition, since the first reference value of the angular velocity sensor 12 can be corrected based on the motion vector obtained from the camera body 1A and the information indicating the calculation level, the first reference value is converted to a true value as shown in FIG. A close reference value can be obtained.
Interchangeable lenses can be mounted on various types of camera bodies. By receiving information indicating the calculation level from the mounted camera body, it is possible to perform shake correction control according to the mounted camera body.

  Further, the motion vector information is transmitted from the body side transmitting / receiving section 21 to the lens side transmitting / receiving section 22. Therefore, even when the camera body 1A and the interchangeable lens 1B are separate, the interchangeable lens 1B can receive the motion vector information from the camera body 1A.

The interchangeable lens 1B includes a lens storage unit 45 that stores the minimum focal length information set for each calculation level, and the reference value correction unit 50 determines that the focal length is smaller than the minimum focal length corresponding to the received calculation level. , The first reference value is not corrected based on the motion vector information.
When the focal length of the interchangeable lens 1B is short (wide), if the blur correction control is performed using the motion vector information having a low calculation level, the blur correction performance may be deteriorated as compared with the case where the motion vector information is not used. .
However, according to the present embodiment, when the focal length is smaller than the minimum focal length information stored in the lens storage unit 45 for each calculation level, the interchangeable lens 1B uses the first reference value using the motion vector information. Since no correction is performed, it is possible to perform a suitable blur correction without deteriorating the motion blur correction performance.

The lens-side transmitting / receiving unit 22 can transmit information on the focal length to the camera body 1A.
Therefore, when the focal length of the interchangeable lens 1B is on the wide side, the operation timing of the motion vector information can be lengthened, and the detection accuracy of the motion vector information can be improved.
In the above-described embodiment, the center bias, which is a centripetal force for moving the blur correction lens toward the center of its movable range, is used based on the target position of the blur correction lens calculated by the target position calculation unit. However, control without using the center bias may be performed. In that case, there is no center bias calculator and no center bias remover.

The present invention is not limited to the embodiments described above, and various modifications and changes as described below are possible, and these are also within the scope of the present invention.
(1) In the above-described embodiment, the form in which the quick return mirror is not provided in the camera body 1A has been described. However, the present invention is not limited to this. Is also good.
(2) In the present embodiment, the interchangeable lens 1B has the structure in which the angular velocity sensor 12 is provided. However, the present invention is not limited to this, and the angular velocity sensor 12 may be provided in the camera body 1A.
Instead of the angular velocity sensor, an acceleration sensor may be provided in the camera body 1A or the interchangeable lens 1B.
(3) In the present embodiment, the shake detected by driving the blur correction lens 6 of the interchangeable lens 1B is corrected. However, the shake detected by driving the image sensor 3 may be corrected.

  1: Camera system, 1A: Camera body, 1B: Interchangeable lens, 2A: Body CPU, 2B: Lens CPU, 2B: Interchangeable lens, 3: Image sensor, 4: Zoom lens, 5: Focus lens, 6: Shake correction lens , 7: zoom lens driving mechanism, 8: focus lens driving mechanism, 9: blur correction lens driving mechanism, 10: aperture, 11: driving mechanism, 12: angular velocity sensor, 13: recording medium, 14: body storage unit, 16: Photographing lens, 21: body side transmission / reception section, 22: lens side transmission / reception section, 23: blur correction lens position detection section, 24: focal length detection section, 31: amplification section, 32: first A / D conversion section, 33: section 2A / D converter, 34: reference value calculator, 35: reference value correction amount calculator, 36: target position calculator, 37: center bias calculator, 38: center bias remover, 3 : Drive amount calculation section, 40: signal processing section, 41: vector calculation section, 42: reference value deduction / addition section, 43: subtraction section, 44: judgment section, 45: lens storage section, 50: reference value correction section, 100 : Image stabilization mechanism

Claims (15)

An interchangeable lens that can be attached to the camera body,
An optical system having a blur correction optical system that forms a subject image and corrects the blur of the subject image;
A motion vector calculated from an image generated by imaging the subject image formed by the optical system, and a receiving unit that receives information indicating the operation level of the motion vector of the camera body from the camera body,
Interchangeable lens provided with. The interchangeable lens according to claim 1,
An interchangeable lens including a drive unit that drives the blur correction optical system based on the motion vector, information indicating a calculation level of the motion vector, and a blur detection signal output from a blur detection unit that detects blur. The interchangeable lens according to claim 2,
A reference value calculation unit that calculates a reference value of a shake detection signal output from the shake detection unit,
A reference value correction unit that calculates a correction reference value obtained by correcting the reference value based on the motion vector,
Interchangeable lens provided with. The interchangeable lens according to claim 3,
An interchangeable lens that determines whether or not to correct the reference value based on the motion vector, based on the information indicating the calculation level and the information on the focal length of the interchangeable lens. The interchangeable lens according to claim 4,
An interchangeable lens that determines whether or not the reference value corrector corrects the reference value with the motion vector based on a focal length set for each calculation level and a focal length of the interchangeable lens. . The interchangeable lens according to claim 5,
An interchangeable lens, wherein the reference value correction unit determines that the reference value correction unit corrects the reference value with the motion vector when a focal length of the interchangeable lens is equal to or longer than a focal length set for each calculation level. The interchangeable lens according to claim 5, wherein
An interchangeable lens wherein a focal length set for each of the calculation levels is shorter as the calculation level is higher. The interchangeable lens according to any one of claims 3 to 7,
A target position calculation unit that calculates a drive target position of the shake correction optical system from the correction reference value and the shake detection signal;
The drive unit is an interchangeable lens that drives the blur correction optical system to the drive target position. The interchangeable lens according to claim 8,
An interchangeable lens having a target position correction unit that corrects the drive target position to a position close to the optical axis of the optical system. The interchangeable lens according to claim 9,
An interchangeable lens having a motion vector correction unit that calculates a corrected motion vector by correcting the motion vector based on a correction amount that corrects the drive target position to a position near the optical axis of the optical system. The interchangeable lens according to claim 10,
An interchangeable lens that calculates the corrected reference value by correcting the reference value, using the corrected motion vector as the motion vector. The interchangeable lens according to claim 11,
The target position calculation unit calculates the drive target position of the blur correction optical system from the corrected reference value obtained by correcting the reference value and the blur detection signal, using the corrected motion vector as the motion vector. And
The drive unit is an interchangeable lens that drives the blur correction optical system to the drive target position. The interchangeable lens according to any one of claims 3 to 12,
The receiving unit calculates a motion vector detection delay time from the camera body, which is a difference between a time at which the image at which the motion vector is calculated and the time at which the motion vector is transmitted from the camera body to the interchangeable lens. Receive,
An interchangeable lens that corrects the reference value calculated before the motion vector detection delay time based on the received motion vector. The interchangeable lens according to any one of claims 1 to 13,
An interchangeable lens having a lens-side transmission unit that transmits information indicating that the reference value is corrected based on the information of the motion vector to the camera body. A camera body attachable to an interchangeable lens having a shake correction optical system,
An imaging unit that captures a subject image formed by the interchangeable lens;
A motion vector calculation unit that calculates a motion vector from an image captured and generated by the imaging unit;
A storage unit that stores information indicating a calculation level of the motion vector of the camera body;
A transmitting unit that transmits the motion vector and the information indicating the calculation level used for controlling the shake correction optical system to the interchangeable lens;
Camera body with.

Images