JP7017961B2 - Blur correction device and blur correction method - Google Patents

Description

The present invention relates to a blur correction device and a blur correction method for detecting shake of an apparatus including an optical system and correcting image blur caused by the detected shake.

In recent years, the image stabilization function of digital cameras has been steadily improving. Digital cameras that have achieved image stabilization performance that exceeds the number of shutter speeds for five steps have also appeared, with respect to the shutter speed that is the limit of camera shake. In the following, digital cameras are simply referred to as "cameras."

One of the factors is the improvement of the detection accuracy due to the improvement of the performance of the sensor that detects the shaking of the device.
In general, the gyro sensor used for image stabilization causes fluctuations in the detection result and offset fluctuations called drifts due to various factors. Therefore, the detection accuracy can be improved by suppressing this.

As an example of the technique for improving the detection accuracy, the blur detection device disclosed in Patent Document 1 is known. In this blur detection device, the first reference value calculation unit calculates a drift component included in the blur detection signal output by the blur detection unit, and outputs this drift component as the first reference value of the blur detection signal. Further, the second reference value calculation unit calculates and outputs the second reference value of the blur detection signal by calculating the difference between the blur detection signal output by the blur detection unit and the drift component. Further, when the elapsed time from the start of the blur detection signal output by the blur detection unit is less than the predetermined time, the reference value selection unit selects the first reference value, and the elapsed time is equal to or longer than the predetermined time. When is, the above-mentioned second reference value is selected. Then, the reference value selected by the reference value selection unit is used as the reference value for the blur correction control. This prevents the calculation error of the reference value from increasing due to the influence of drift.

Japanese Patent No. 4051738

On the other hand, since the gyro sensor detects the rotational motion of the device, as the detection accuracy improves, the influence of the rotational motion due to the rotation of the earth cannot be ignored.
In the case of image stabilization, since both the camera and the subject are on the earth, the relative positional relationship between the camera and the subject does not change even if a rotational movement occurs due to the rotation of the earth. Therefore, if the rotation component due to the rotation of the earth detected by the camera is corrected, it will be an erroneous correction.

Here, let us consider how much the rotation of the earth affects the image stabilization.
Since the rotation of the earth is 0.004167 dps, when an image is taken with an optical system having a focal length of 100 mm, an image movement of about 7.3 μm occurs per second. As a result, image blurring of one pixel or more occurs depending on the pixel pitch of the image sensor. Note that dps is an abbreviation for degree per second.

In view of the above circumstances, the present invention can eliminate the influence of the rotation of the earth, which becomes a problem when the detection accuracy of the sensor used for image stabilization is improved to the utmost limit, and improve the image stabilization performance. It is an object of the present invention to provide a blur correction device and a blur correction method.

The first aspect of the present invention is a blur correction device, in which a first angular velocity sensor for detecting an angular velocity in a first rotational direction of an apparatus including an optical system and an angular velocity in the second rotational direction of the apparatus are measured. A second angular velocity sensor to detect, a gravity sensor to detect the direction of gravity with respect to the device, an attitude detection unit to detect the posture of the device based on the direction of gravity detected by the gravity sensor, and a latitude of the device. Based on this, the first calculation unit that calculates the angular velocity of the rotational motion around the vertical axis as the rotation axis, which occurs in the device due to the rotation of the earth, as the first rotation offset amount, the latitude of the device, and the above. Based on the orientation in the optical axis direction of the optical system, the angular velocity of the rotational motion generated in the device due to the rotation with the axis orthogonal to the vertical axis as the rotation axis is calculated as the second rotation offset amount. When the second calculation unit and the posture detected by the posture detection unit are the first posture, the first rotation offset amount is subtracted from the angular speed detected by the first angular velocity sensor, and the posture is described. When the posture detected by the detection unit is the second posture, the first subtraction unit that subtracts the second rotation offset amount from the angular speed detected by the first angular velocity sensor and the attitude detection unit detect it. When the posture is the first posture, the second rotation offset amount is subtracted from the angular speed detected by the second angular velocity sensor, and the posture detected by the posture detecting unit is the second posture. In some cases, the second subtraction unit for subtracting the first rotation offset amount from the angular velocity detected by the second angular velocity sensor is provided, and the rotation axis in the first rotation direction and the second rotation are provided. The rotation axes in the directions are orthogonal to each other, and the first posture is a posture when the inclination of the rotation axis in the first rotation direction with respect to the vertical axis is within a predetermined angle range, and the second posture. Is characterized in that it is a posture when the inclination of the rotation axis in the second rotation direction with respect to the axis in the vertical direction is within a predetermined angle range.

A second aspect of the present invention is, in the first aspect, whether or not the attitude change in the first rotation direction of the apparatus has not been continuously performed for a predetermined period based on the angular velocity detected by the first angular velocity sensor. Based on the first determination unit for determining whether or not the device and the angular velocity detected by the second angular velocity sensor, it is determined whether or not the attitude of the device in the second rotation direction has not changed continuously for the predetermined period. The second determination unit, the first reference value calculation unit that calculates the first reference value to be subtracted from the angular velocity detected by the first angular velocity sensor based on the determination result of the first determination unit. The second reference value calculation unit for calculating a second reference value subtracted from the angular velocity detected by the second angular velocity sensor based on the determination result of the second determination unit is further provided. When the first determination unit determines that the attitude change in the first rotation direction of the device has not been continuously performed for the predetermined period, the reference value calculation unit 1 has the first angular velocity during the predetermined period. The first reference value is calculated based on the result of subtracting the first rotation offset amount or the second rotation offset amount from each of the angular velocities detected by the sensor, and the second reference value calculation unit is used. From each of the angular velocities detected by the second angular velocity sensor during the predetermined period when the second determination unit determines that the attitude change in the second rotation direction of the device has not been continuously performed for the predetermined period. It is characterized in that the second reference value is calculated based on the result of subtracting the first rotation offset amount or the second rotation offset amount.

A third aspect of the present invention is characterized in that, in the first or second aspect, an input unit for inputting the latitude of the device is further provided.
A fourth aspect of the present invention is characterized in that, in the first or second aspect, a selection unit for selecting the latitude of the device is further provided.

A fifth aspect of the present invention is characterized in that, in the first or second aspect, a latitude detection unit for detecting the latitude of the apparatus is further provided.
A sixth aspect of the present invention is characterized in that, in the fifth aspect, the latitude detection unit is a GPS receiving device.

A seventh aspect of the present invention is characterized in that, in the first or second aspect, a communication unit that communicates with an external device is further provided, and the communication unit receives the latitude of the device from the external device. do.
An eighth aspect of the present invention is characterized in that, in any one of the first to seventh aspects, an orientation sensor for detecting the orientation of the optical system in the optical axis direction is further provided.

A ninth aspect of the present invention is, in any one of the first to eighth aspects, a first correction coefficient calculation for calculating a first correction coefficient for correcting the angular velocity detected by the first angular velocity sensor. A unit and a second correction coefficient calculation unit for calculating a second correction coefficient for correcting the angular speed detected by the second angular velocity sensor are further provided, and the first correction coefficient calculation unit rotates. The rotating device is installed for the purpose that the rotation axis of the rotating portion provided in the device is parallel to the latitude line, and the rotation axis of the rotating portion and the rotation axis in the first rotation direction are parallel to each other. After the blur correction device is fixed to the rotating portion, the first correction coefficient is calculated based on the angular velocity detected by the first angular velocity sensor when the rotating device rotates the rotating portion. In the second correction coefficient calculation unit, the rotation device is installed for the purpose of making the rotation axis of the rotation unit parallel to the graticule, and the rotation axis of the rotation unit and the rotation axis in the second rotation direction are installed. After the blur correction device is fixed to the rotating portion for the purpose of being parallel to each other, the second angular velocity detected by the second angular velocity sensor when the rotating device rotates the rotating portion. It is characterized in that the correction coefficient of 2 is calculated.

A tenth aspect of the present invention is characterized in that, in any one of the first to ninth aspects, the device is an image pickup device including the blur correction device.
The eleventh aspect of the present invention is characterized in that, in any one of the first to tenth aspects, the first rotation direction is the Yaw direction and the second rotation direction is the Pitch direction. And.

A twelfth aspect of the present invention is a blur correction method, in which an angular velocity in a first rotation direction of an apparatus including an optical system is detected, and an angular velocity in a second rotation direction of the apparatus is detected. , Detecting the direction of gravity with respect to the device, detecting the attitude of the device based on the detected direction of gravity, and based on the latitude of the device, the vertical that occurs in the device due to the rotation of the earth. The angular velocity of the rotational motion with the axis of direction as the axis of rotation is calculated as the first rotation offset amount, and based on the latitude of the device and the orientation of the optical system in the optical axis direction, the rotation causes the above. When the angular velocity of the rotational movement generated in the device with the axis orthogonal to the vertical axis as the rotation axis is calculated as the second rotation offset amount, and when the detected posture is the first posture, The first rotation offset amount is subtracted from the angular velocity in the first rotation direction, and when the detected posture is the second posture, the second rotation offset amount is subtracted from the angular velocity in the first rotation direction. When the detected posture is the first posture, the second rotation offset amount is subtracted from the angular velocity in the second rotation direction, and the detected posture is the second posture. In the case of the posture, the rotation axis in the first rotation direction and the rotation axis in the second rotation direction include subtracting the rotation offset amount of the first rotation from the angular velocity in the second rotation direction. Is orthogonal, the first posture is a posture when the inclination of the rotation axis in the first rotation direction with respect to the vertical axis is within a predetermined angle range, and the second posture is a posture. It is characterized in that it is an attitude when the inclination of the rotation axis in the second rotation direction with respect to the axis in the vertical direction is within a predetermined angle range.

According to the present invention, there is an effect that the influence caused by the rotation of the earth, which becomes a problem when the detection accuracy of the sensor used for image stabilization is improved to the utmost limit, and the image stabilization performance can be improved. Play.

It is a figure which shows typically the cross section of the earth including the earth's axis. It is a figure which shows an example of the influence on the Pitch direction and the Roll direction of a camera by the direction of the optical axis of a camera, and the rotation of the earth. It is a figure which shows the structural example of the camera which is the image pickup apparatus provided with the blur correction apparatus which concerns on 1st Embodiment. It is a figure which shows the functional structure example of the blur correction microcomputer which concerns on 1st Embodiment. It is a figure which shows the functional structure example of the rotation offset calculation part. It is a figure which shows an example of a selection rule. It is a figure which shows the functional structure example of a reference value calculation part. It is a figure which shows the structural example of the camera which concerns on the modification of 1st Embodiment. It is a figure which shows the structural example of the camera which concerns on other modification of 1st Embodiment. It is a figure (the 1) which shows an example of the installation method. It is a figure (2) which shows an example of the installation method. It is a figure which shows the functional structure example of the blur correction microcomputer which concerns on 2nd Embodiment. It is a flowchart which shows the flow of adjustment of the camera which concerns on 2nd Embodiment. It is a figure (the 3) which shows an example of the installation method.

First, in order to facilitate the understanding of the embodiment of the present invention, the influence of the rotation of the earth will be described by taking a camera as an example.

FIG. 1 is a diagram schematically showing a cross section of the earth including the earth's axis.
In FIG. 1, the effect of rotation at latitude θ _latitude appears as a rotational motion around the axis of rotation with a slope of θ _latitude with respect to the horizontal plane. The rotation vector of this rotational motion is defined as Rotation. In FIG. 1, θ _latitude is simply referred to as “θ” due to the space of the drawing.

This rotation vector Rotation can be decomposed into a rotation vector Rot_v around the vertical axis and a rotation vector Rot_h around the horizontal axis. Here, the circumference of the vertical axis can also be said to be the rotation direction with the vertical axis as the rotation axis. Further, the circumference of the horizontal axis can also be said to be a rotation direction having an axis perpendicular to the vertical axis as a rotation axis.

For example, when the camera is held horizontally to take a picture of a horizontal composition, the rotation of the camera in the Yaw direction has a constant angular velocity, and the rotation of the camera in the Pitch direction and the Roll direction is due to the orientation of the optical axis of the camera. It fluctuates. In this case, the Yaw direction of the camera is also around the vertical axis, and the Pitch direction and Roll direction of the camera are also around the horizontal axis. Hereinafter, the optical axis of the camera is also referred to as a "camera optical axis".

FIG. 2 is a diagram showing an example of the influence of the direction of the optical axis of the camera and the rotation of the earth on the Pitch direction and the Roll direction of the camera.
In FIG. 2, when the north is 0 °, the rotation vector Rot_h around the horizontal axis is rotated from the angle θ _direction formed by the meridional line and the camera optical axis, the rotation vector Rot_pitch in the Pitch direction of the camera, and the rotation in the Roll direction of the camera. It can be decomposed into the vector Rot_roll.

When the camera optical axis points in the north or south direction, all the components of the rotation vector Rot_h around the horizontal axis affect the Roll direction of the camera, and the camera optical axis points in the east or west direction. All components of the rotation vector Rot_h around the horizontal axis affect the Pitch direction of the camera.
The above is the effect of the rotation of the earth on the camera.

Here, we consider a case that causes a problem in actual shooting.
In order to accurately detect the amount of image blur from the detected angular velocity in the camera, the calculation accuracy of the reference value is important. Hereinafter, the detected angular velocity is also referred to as “detected angular velocity”. The reference value is the detection angular velocity when the camera is stationary.

Assuming that the latitude and the direction of the camera optical axis are constant, the reference value can be obtained from the detected angular velocity affected by the rotation of the earth, and the reference value can be subtracted from the detected angular velocity affected by the rotation of the earth. The effect of rotation is removed and it does not matter.

On the other hand, although the latitude does not change, if the direction of the camera optical axis when the reference value is calculated and the direction of the camera optical axis when performing image stabilization are different, the effect on the camera's Pitch direction and Roll direction is affected. Because they are different, an offset error occurs.

For example, when shooting is performed with the camera optical axis facing east while keeping the reference value calculated when the camera optical axis is facing west, an error of twice occurs with respect to the rotation vector Rot_pitch in the Pitch direction of the camera.

Further, when the latitude of the shooting point changes significantly with respect to the latitude of the point where the reference value is calculated, an error also occurs.
For example, if the reference value is calculated at the position of 30 degrees north latitude and then moved to 30 degrees south latitude, an error of about twice with respect to the rotation vector Rot_yaw in the Yaw direction of the camera occurs.

In this case, the rotation vector Rot_roll in the Roll direction of the camera does not have an effect so as to appear as an image blur on the captured image, so that there is no particular problem.
Based on the above, embodiments of the present invention will be described below with reference to the drawings.
<First Embodiment>

FIG. 3 is a diagram showing a configuration example of a camera which is an image pickup device provided with a blur correction device according to the first embodiment. However, in FIG. 3, only the main configurations related to image stabilization are shown, and the other configurations are omitted.

In FIG. 3, the camera 1 according to the present embodiment includes an optical system 2, an image sensor 3, a drive unit 4, a system controller 5, a blur correction microcomputer 6, an angular velocity sensor 7, an acceleration sensor 8, an orientation sensor 9, a memory 10, and an EVF 11. , And SW12. Here, EVF is an abbreviation for electronic viewfinder.

The optical system 2 forms a light beam from the subject on the image pickup device 3. The luminous flux from the subject is also called a subject image. In FIG. 3, for convenience of explanation, the optical system 2 is shown in a simplified manner, but in reality, the optical system 2 is composed of a plurality of lenses including a focus lens and a zoom lens.

The image pickup element 3 converts the subject image formed on the image pickup surface by the optical system 2 into an electric signal. The image sensor 3 is an image sensor such as a CCD or CMOS. CCD is an abbreviation for charge coupled device, and CMOS is an abbreviation for complementary metal oxide semiconductor.

The angular velocity sensor 7 detects the angular velocity of the camera 1 in the Yaw direction and the Pitch direction.
The acceleration sensor 8 detects the acceleration of the X-axis, Y-axis, and Z-axis of the camera 1.
Here, the X-axis is also a rotation axis in the Yaw direction and a vertical axis of the camera 1. The Y-axis is also a rotation axis in the Pitch direction and a horizontal axis of the camera 1. The Z axis is also the optical axis of the optical system 2.

The orientation sensor 9 detects the geomagnetism and detects the orientation of the optical axis of the optical system 2 on the subject side based on the detected geomagnetism.
The blur correction microcomputer 6 acquires detection results from the angular velocity sensor 7, the acceleration sensor 8, and the orientation sensor 9, and also acquires the focal length information of the optical system 2 and the latitude information of the camera 1 from the system controller 5. Then, the blur correction microcomputer 6 controls the drive unit 4 in order to move the image pickup element 3 in the direction of canceling the blurring of the subject image imaged on the image pickup surface of the image pickup element 3. The details of the blur correction microcomputer 6 will be described later with reference to FIG.

The drive unit 4 moves the image sensor 3 on a plane orthogonal to the optical axis of the optical system 2 under the control of the blur correction microcomputer 6. The drive unit 4 is composed of, for example, a plurality of actuators and the like. The actuator is, for example, a VCM. VCM is an abbreviation for Voice Coil Motor.

The EVF 11 displays captured still images, moving images, live view images, various camera setting screens, and the like. For example, EVF 11 displays a country setting screen as one of the camera setting screens. On this country setting screen, a plurality of countries that the user can select as the country in which the camera 1 is used are displayed.

The SW12 is an operation unit that detects various input operations of the user such as button operations and notifies the system controller 5. For example, the SW12 detects a country selection and determination instruction operation on the country setting screen and notifies the system controller.

The memory 10 is a non-volatile memory, and characteristic information of the optical system 2 and latitude information for each country are recorded in advance. Here, the latitude information for each country is information regarding the standard latitude for each country.

The system controller 5 controls the overall operation of the camera 1. For example, the system controller 5 reads out the electric signal converted by the image sensor 3 as video data, and performs image processing for displaying the video data on the EVF 11. Further, for example, the system controller 5 notifies the blur correction microcomputer 6 of a value corresponding to the focal length as focal length information based on the state of the optical system 2 and the characteristic information of the optical system 2 recorded in the memory 10. do. Further, for example, the system controller 5 uses the standard latitude of the country selected and determined by the user on the country setting screen as the latitude information of the camera 1 based on the latitude information of each country recorded in the memory 10, and the blur correction microcomputer 6 Notify to. In this case, since the standard latitude of the country selected and determined by the user by the operation of SW12 becomes the latitude information of the camera 1, it can be said that the SW12 also has the function of the selection unit for selecting the latitude of the camera 1. ..

In the camera 1, each of the system controller 5 and the blur correction microcomputer 6 includes, for example, a processor such as a CPU and a memory, and the processor executes a program recorded in the memory, so that the system controller 5 and the blur correction microcomputer 6 are executed. Each function of is realized. Alternatively, each of the system controller 5 and the blur correction microcomputer 6 may be composed of a dedicated circuit such as an ASIC or an FPGA. ASIC is an abbreviation for application specific integrated circuit, and FPGA is an abbreviation for field-programmable gate array.

FIG. 4 is a diagram showing a functional configuration example of the blur correction microcomputer 6.
However, FIG. 4 illustrates only the functional configuration for processing one of the angular velocities in the Yaw direction and the Pitch direction detected by the angular velocity sensor 7 as the functional configuration for processing the angular velocity detected by the angular velocity sensor 7, and the other angular velocity. Since the functional configuration for performing the processing for is the same, the illustration is omitted. Therefore, in reality, two functional configurations including the reference value calculation unit 61, the subtraction unit 62, the subtraction unit 63, the multiplication unit 64, the integration unit 65, and the correction amount calculation unit shown in FIG. 4 are provided.

Further, as a method for the blur correction microcomputer 6 to acquire the detection results of the angular velocity sensor 7, the acceleration sensor 8, and the orientation sensor 9, the analog signal output as the detection result by each sensor is AD in the blur correction microcomputer 6. There are two methods, one is a method of converting and the other is a method in which the blur correction microcomputer 6 reads out the value obtained by converting the detection result into a digital signal in each sensor by using serial communication. In the present embodiment, either of these two methods may be adopted, and since both methods are known, the illustration is omitted.

In FIG. 4, the blur correction microcomputer 6 includes a reference value calculation unit 61, a subtraction unit 62, a subtraction unit 63, a multiplication unit 64, an integration unit 65, a correction amount calculation unit 66, a communication unit 67, an orientation detection unit 68, and a posture determination unit. 69 and the rotation offset calculation unit 6A are included.

The communication unit 67 communicates with the system controller 5 and acquires focal length information and latitude information from the system controller 5. Then, the focal length information is output to the multiplication unit 64, and the latitude information is output to the rotation offset calculation unit 6A.

The direction detection unit 68 acquires the direction detected by the direction sensor 9, and calculates an angle indicating the direction when the north is set to 0 °.
The posture determination unit 69 detects 1G from the X-axis, Y-axis, and Z-axis accelerations acquired from the acceleration sensor 8, and the posture of the camera 1 is "horizontal composition", "vertical composition", "up and down", and Which of the four posture patterns of "tilted" is determined according to the following criteria (1) to (4). Here, 1G is gravity. The posture determination unit 69 is an example of a posture detection unit that detects the posture of the camera 1.
(1) If there is 1G in the Y-axis direction and the vertical axis of the camera 1 and the inclination in the 1G direction are within 20 °, the “horizontal composition” is used. In this case, the inclination of the rotation axis of the camera 1 in the Yaw direction with respect to the vertical axis may be within 20 °.
(2) If there is 1G in the X-axis direction and the horizontal axis of the camera 1 and the inclination in the 1G direction are within 20 °, the “vertical composition” is used. In this case, the inclination of the rotation axis of the camera 1 in the Pitch direction with respect to the vertical axis may be within 20 °.
(3) When there is 1G in the Z-axis direction and the inclination of the optical system 2 in the optical axis and the 1G direction is within 20 °, it is defined as "up and down".
(4) If any of the above (1) to (3) does not apply, it is regarded as "inclined".

The rotation offset calculation unit 6A moves in the Yaw direction and the Pitch direction of the camera 1 based on the latitude indicated by the latitude information acquired from the communication unit 67, the angle acquired from the direction detection unit 68, and the attitude determined by the attitude determination unit 69. Calculate the amount of rotation offset that occurs. The details of the rotation offset calculation unit 6A will be described later with reference to FIG.

The reference value calculation unit 61 calculates the reference value. The details of the reference value calculation unit 61 will be described later with reference to FIG. 7.
The subtraction unit 62 subtracts the reference value calculated by the reference value calculation unit 61 from the angular velocity acquired from the angular velocity sensor 7.

The subtraction unit 63 subtracts the rotation offset amount calculated by the rotation offset calculation unit 6A from the subtraction result of the subtraction unit 62.
The multiplication unit 64 multiplies the subtraction result of the subtraction unit 63 by the focal length information output by the communication unit 67. Here, the focal length information is a value corresponding to the focal length.

The integration unit 65 calculates the amount of blurring of the subject image imaged on the image pickup surface of the image pickup device 3 by time-integrating the multiplication result of the multiplication unit 64. Here, the amount of blurring of the image movement amount is also the image movement amount.
The correction amount calculation unit 66 calculates the drive amount of the drive unit 4 for moving the image pickup element in the direction of canceling the image movement amount calculated by the integration unit 65, and outputs the drive amount to the drive unit 4. Here, the driving amount of the driving unit 4 is also a correction amount.

FIG. 5 is a diagram showing a functional configuration example of the rotation offset calculation unit 6A.
In FIG. 5, the rotation offset calculation unit 6A includes a vertical axis offset calculation unit 6A1, a horizontal axis offset calculation unit 6A2, an orientation correction unit 6A3, and a selector 6A4.

The vertical axis offset calculation unit 6A1 calculates the angular velocity (Rot_v) generated around the vertical axis due to the rotation of the earth based on the latitude indicated by the latitude information output by the communication unit 67, using the following equation (1). ..
Rot_v = Rotation × SIN (θ _latitude ) Equation (1)

The offset calculation unit 6A2 around the horizontal axis calculates the angular velocity (Rot_h) generated around the horizontal axis due to the rotation of the earth based on the latitude indicated by the latitude information output by the communication unit 67, using the following equation (2). ..
Rot_h = Rotation × COS (θ _latitude ) Equation (2)

In the above equations (1) and (2), Rotation is the rotation angular velocity of the earth, and θ _latitude is the latitude. The rotation angular velocity of the earth is 0.004167 dps, and Rot_v, Rot_h, θ _latitude and Rotation are as shown in FIG.

The directional correction unit 6A3 calculates Rot_pitch and Rot_Roll using the following equations (3) and (4) based on the calculation result of the horizontal axis offset calculation unit 6A2, the attitude information, and the directional information. Here, the posture information is the determination result of the posture determination unit 69, and the directional information is the calculation result of the azimuth detection unit 68.
Rot_pitch = Rot_h × SIN (θ _direction ) Equation (3)
Rot_Roll = Rot_h × COS (θ _direction ) Equation (4)
Here, the θ _direction differs depending on the determination result of the posture determination unit 69. Specifically, when the posture determined by the posture determination unit 69 is any of "horizontal composition", "vertical composition", and "tilted", the θ _direction is set by the optical axis of the optical system 2 and the meridian. Let it be an angle. In this case, the θ _direction in the case of “horizontal composition” or “vertical composition” is also the angle calculated by the direction detection unit 68. On the other hand, when the posture determined by the posture determination unit 69 is "up and down", θ _direction is set as the angle formed by the vertical axis of the camera 1 and the meridian. The vertical axis of the camera 1 is also the Y axis of the camera 1.

The selector 6A4 is a rotation offset amount in each direction in the Yaw direction and the Pitch direction from the Rot_v calculated by the vertical axis offset calculation unit 6A1 and the Rot_pitch and Rot_Roll calculated by the direction correction unit 6A3 based on the attitude information. Select and output what to do according to a predetermined selection rule. Here, the posture information is also the determination result of the posture determination unit 69.

FIG. 6 is a diagram showing an example of a predetermined selection rule.
According to the selection rule shown in FIG. 6, when the determination result of the attitude determination unit 69 is "horizontal composition", the selector 6A4 selects Rot_v as the rotation offset amount in the Yaw direction, and the rotation offset in the Pitch direction. Select Rot_pitch as the quantity. On the other hand, in the case of the "vertical composition" posture, on the contrary, Rot_pitch is selected as the rotation offset amount in the Yaw direction, and Rot_v is selected as the rotation offset value in the Pitch direction. In the "up and down" posture, Rot_roll is selected as the rotation offset value in the Yaw direction, and Rot_pitch is selected as the rotation offset amount in the Pitch direction. In the case of "with tilt", since the tilt of the camera 1 is large, the selector 6A4 does not select anything in order to prevent the subtraction of the rotation offset amount and the calculation of the reference value based on the rotation offset amount. 0 is output as the rotation offset amount in each of the Yaw direction and the Pitch direction.

FIG. 7 is a diagram showing a functional configuration example of the reference value calculation unit 61.
In FIG. 7, the reference value calculation unit 61 includes a subtraction unit 611, a posture change determination unit 612, an average value buffer unit 613, and a reference value calculation unit 614.

The subtraction unit 611 subtracts the rotation offset amount output from the rotation offset calculation unit 6A from the angular velocity acquired from the angular velocity sensor 7.
The average value buffer unit 613 calculates the average value of the subtraction results of the subtraction unit 611 in the predetermined period for each predetermined period, and holds a plurality of average values for the latest continuous plurality of predetermined periods. Here, the predetermined period is, for example, 100 ms.

The posture fluctuation determination unit 612 determines whether or not the posture of the camera 1 has changed from the angular velocity acquired from the angular velocity sensor 7, and outputs a reference value calculation instruction to the reference value calculation unit 614 when there is no posture change for a predetermined period. .. Here, the predetermined period is, for example, 1 second or more.
The reference value calculation unit 614 further averages a plurality of average values held in the average value buffer unit 613 in response to an input of a calculation instruction from the posture change determination unit 612, and calculates the reference value as a reference value.

According to the first embodiment described above, the influence due to the rotation is removed from the calculated reference value, and the influence due to the rotation is also removed from the detected angular velocity. Therefore, even if the direction of the camera 1 is changed or the latitude of the camera 1 is changed, the influence of the rotation is completely eliminated, so that highly accurate blur detection performance can be maintained.

In the present embodiment, the latitude information notified by the system controller 5 to the blur correction microcomputer 6 may be based on the area selected and determined by the user on the area setting screen provided instead of the country setting screen. .. In this case, the latitude information for each region may be recorded in the memory 10 in advance instead of the latitude information for each country. The area in this case is, for example, one area when the area of the country is divided into a plurality of areas.
According to this configuration, the latitude of the camera 1 can be made more accurate than when selecting and deciding on the country setting screen.

Further, in the present embodiment, the latitude indicated by the latitude information notified by the system controller 5 to the blur correction microcomputer 6 may be a latitude directly input by the user by operating the SW 12. In this case, the SW 12 also has a function of an input unit for inputting the latitude of the camera 1.
According to this configuration, since the user can directly input the latitude of the camera 1, the latitude of the camera 1 can be made more accurate than when selecting and deciding on the country setting screen.

Further, in the present embodiment, as shown in FIG. 8, the camera 1 may be further provided with the GPS receiving device 13. GPS is an abbreviation for Global Positioning System. The GPS receiving device 13 calculates the position information of the current position of the camera 1 by receiving radio waves transmitted from a plurality of GPS satellites, and notifies the system controller 5. Then, the latitude information notified by the system controller 5 to the blur correction microcomputer 6 may be configured to be the latitude information included in the position information notified from the GPS receiving device 13. In this case, the GPS receiving device 13 also has a function of a latitude detection unit that detects the latitude of the camera 1.
According to this configuration, the latitude of the camera 1 can be automatically updated by the GPS receiving device 13, so that the user does not need to reset the country setting when the position of the camera 1 changes. Moreover, since even a slight change in latitude can be detected, the influence of the rotation of the earth can be removed with high accuracy.

Further, in the present embodiment, as shown in FIG. 9, the camera 1 may be further provided with the communication unit 14. The communication unit 14 communicates with an external device by wireless communication such as WiFi or Bluetooth (registered trademark). For example, the communication unit 14 communicates with an external device capable of acquiring latitude information under the control of the system controller 5, acquires latitude information from the external device, and notifies the system controller 5. Here, the external device capable of acquiring latitude information is, for example, a smartphone or a server that provides location information. The latitude information notified by the system controller 5 to the blur correction microcomputer 6 may be the latitude information notified by the communication unit 14.
According to this configuration, it is possible to acquire latitude information without providing a latitude detecting means such as a GPS receiving device, so that the cost required for acquiring latitude information can be suppressed.
<Second embodiment>

Next, the second embodiment will be described. In this description, only the differences from the first embodiment will be described. Further, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The camera 1, which is an image pickup device provided with the blur correction device according to the second embodiment, has an adjustment function for eliminating a sensitivity error included in the detection result of the angular velocity sensor 7.
Specifically, the adjustment function is given CW rotation and CCW rotation of a predetermined rotation speed to the rotation axis to be adjusted depending on the rotation device, and averages the absolute values of the detected angular velocities at each rotation. Therefore, the average detection angular velocity for a predetermined rotation speed is calculated, and the correction coefficient is calculated for the purpose of making this average detection angular velocity a predetermined rotation speed. Here, CW means clockwise and CCW means counterclockwise.

At this time, the direction of the camera 1 changes due to the rotation depending on the installation direction of the rotation axis to be adjusted. As a result, the influence of the rotation of the earth also fluctuates due to the directional change, and an error occurs in the calculated correction coefficient. Therefore, it is necessary to install it for the purpose of not causing the influence of the rotation of the earth.

10A and 10B are diagrams showing an example of the installation method at this time.
FIG. 10A shows an installation method when the rotation axis to be adjusted is the rotation axis in the Yaw direction of the camera 1. FIG. 10B shows an installation method when the rotation axis to be adjusted is the rotation axis in the Pitch direction of the camera 1.

In FIGS. 10A and 10B, the rotation device 101 is installed for the purpose that the rotation axis 103 of the rotation unit 102 included in the rotation device 101 is parallel to the graticule, and the rotation axis 103 of the rotation unit 102 is the adjustment target of the camera 1. The camera 1 is fixed to the rotating portion 102 for the purpose of being parallel to the rotating axis.

That is, when the rotation axis to be adjusted is the rotation axis in the Yaw direction, as shown in FIG. 10A, the rotation axis 103 of the rotation unit 102 included in the rotation device 101 and the rotation in the Yaw direction to be adjusted by the camera 1 It is installed for the purpose of making the axis parallel to the saw line.

When the rotation axis to be adjusted is the rotation axis in the Pitch direction, as shown in FIG. 10B, the rotation axis 103 of the rotation unit 102 included in the rotation device 101 and the rotation in the Pitch direction to be adjusted by the camera 1 It is installed for the purpose of making the axis parallel to the parallels.

FIG. 11 is a diagram showing a functional configuration example of the blur correction microcomputer 6 according to the second embodiment.
In FIG. 11, the blur correction microcomputer 6 according to the second embodiment has a temporary storage unit 6B as a configuration related to an adjustment function with respect to the blur correction microcomputer 6 according to the first embodiment shown in FIG. It includes a coefficient calculation unit 6C, a coefficient holding unit 6D, and a multiplication unit 6E.

The temporary storage unit 6B temporarily holds the angular velocity acquired from the angular velocity sensor 7.
In the second embodiment, when the user sets the adjustment mode as the operation mode of the camera 1 by operating the SW12, the functions of the rotation offset calculation unit 6A and the reference value calculation unit 61 are stopped, and the respective outputs are output. It becomes zero. As a result, the subtraction unit 62 and the subtraction unit 63 output the angular velocity acquired from the angular velocity sensor 7 to the subsequent stage as it is, and the angular velocity temporarily held by the temporary storage unit 6B is the angular velocity acquired from the angular velocity sensor 7. Become.

The coefficient calculation unit 6C calculates the correction coefficient based on the angular velocity held by the temporary storage unit 6B. The coefficient calculation unit 6C calculates the correction coefficient only when the adjustment mode is set as the operation mode of the camera 1. Details of the calculation of the correction coefficient will be described later.

The coefficient holding unit 6D is a non-volatile memory and holds the correction coefficient calculated by the coefficient calculating unit 6C. The coefficient holding unit 6D once holds the correction coefficient, and then continues to hold the correction coefficient unless the coefficient calculation unit 6C newly calculates the correction coefficient.

The multiplication unit 6E multiplies the subtraction result of the subtraction unit 63 by the correction coefficient held by the coefficient holding unit 6D, and outputs the result to the multiplication unit 64.
Along with this, the multiplication unit 64 multiplies the multiplication result of the multiplication unit 6E by the focal length information output by the communication unit 67.
In FIG. 11, the functional configuration of the other blur correction microcomputer 6 is the same as that of the first embodiment.

FIG. 12 is a flowchart showing the flow of adjustment of the camera 1.
This flowchart includes processing related to the adjustment function of the camera 1 and processing of the rotating device 101. For the adjustment of the camera 1, the user sets the adjustment mode as the operation mode of the camera 1 by operating the SW12, and the camera is as shown in FIGS. 10A or 10B depending on the rotation axis to be adjusted by the camera 1. 1 is fixed to the rotating portion 102 of the rotating device 101, and then the operation is started.

In FIG. 12, when the adjustment of the camera 1 is started, the rotating device 101 first starts rotating the rotating unit 102 in the CW direction at a predetermined rotation speed ω_cal (S1).
Next, the camera 1 acquires the angular velocity of the rotation axis to be adjusted from the angular velocity sensor 7 and holds it in the temporary storage unit 6B (S2), which is repeated for 1 second (S3 is NO).

Then, when 1 second elapses (S3 is YES), the coefficient calculation unit 6C of the camera 1 averages the angular velocities held by the temporary storage unit 6B to calculate ωave_cw (S4), and the camera 1 uses the temporary storage unit 6B. To clear.

Next, the rotating device 101 starts rotating the rotating unit 102 in the CCW direction at a predetermined rotation speed ω_cal (S5). That is, the rotating device 101 reverses the rotation direction of the rotating portion 102 at the same rotation speed.

Next, the camera 1 acquires the angular velocity of the rotation axis to be adjusted from the angular velocity sensor 7 and holds it in the temporary storage unit 6B (S6), which is repeated for 1 second (S7 is NO).
Then, when 1 second elapses (S7 is YES), the coefficient calculation unit 6C of the camera 1 averages the angular velocities held by the temporary storage unit 6B to calculate ωave_ccw (S8), and the camera 1 uses the temporary storage unit 6B. To clear.

Next, the coefficient calculation unit 6C of the camera 1 calculates the absolute value ωabs of the detected angular velocity from the ωave_cw calculated in S4 and the ωave_ccw calculated in S8 using the following equation (5) (S9).
ωabs = (｜ ωave_cw ｜ ＋ ｜ ωave_ccw ｜) / 2 Equation (5)
That is, the average value of the absolute value of ωave_cw and the absolute value of ωave_ccw is calculated as ωabs.

Next, the coefficient calculation unit 6C of the camera 1 calculates the correction coefficient K from the predetermined rotation speed ω_cal and the absolute value ωabs of the detection angular velocity calculated in S9 using the following equation (6) (S10). ..
K = ωcal / ωabs equation (6)

Then, the coefficient holding unit 6D holds the correction coefficient K calculated in S10, and the adjustment with respect to the rotation axis to be adjusted by the camera 1 is completed.
After that, when the user changes the operation mode of the camera 1 from the adjustment mode to, for example, the shooting mode by the operation of the SW 12, the camera 1 cancels the function stop of the rotation offset calculation unit 6A and the reference value calculation unit 61.

According to the second embodiment described above, the detection angular velocity can be adjusted by removing the influence of the rotation of the earth, so that the accuracy of the detection angular velocity is improved and the camera shake correction performance of the camera 1 is improved. be able to.

In the present embodiment, for example, when the angular velocity sensor 7 is configured to be able to detect the angular velocity in the Roll direction of the camera 1, the rotation axis to be adjusted is the rotation axis in the Roll direction of the camera 1. The method is as shown in FIG. In this case, as shown in FIG. 13, the rotation axis 103 of the rotation unit 102 included in the rotation device 101 and the rotation axis in the Roll direction to be adjusted by the camera 1 are installed for the purpose of being parallel to the parallels.

By the way, as a sensitivity error included in the detection result of the angular velocity sensor 7, there is other axis sensitivity.
The other axis sensitivity is caused by the inclination of the detection axis of the angular velocity sensor itself and the mounting inclination. In the adjustment of the camera 1 shown in FIG. 12, in S2 and S6, it is possible to detect by reading out the angular velocity of the rotation axis other than the rotation axis to be adjusted.

In S2 and S6, the sensitivity of the other axis is tilted with respect to the rotation axis of the earth depending on the 102 rotations of the rotating portion. Therefore, it is necessary to correct the influence of rotation by the rotation amount θcal of the inclination.
For example, the effect of the rotation of the earth when the vertical axis of the camera 1 rotates by the amount of rotation θcal from the state corresponding to the direction of gravity can be calculated using the following equations (6) and (7).
Rot_v = Rotation × SIN (θ _latitude + θcal) Equation (6)
Rot_h = Rotation × COS (θ _latitude + θcal) Equation (7)

For example, when the rotation axis to be adjusted shown in FIG. 10A is the rotation axis in the Yaw direction of the camera 1, Rot_v calculated by the above equation (6) corresponds to the Pitch direction, and the above equation (7) Rot_h calculated according to the above corresponds to the Roll direction.

In the first and second embodiments, the blur correction device is provided in the camera 1, but the blur correction device may be provided in an optical device such as binoculars other than the camera. In this case, the correction target of the image stabilization device is not the image blur (camera shake) caused by the shake of the camera 1, but the image shake caused by the shake of the optical device.

As described above, the present invention is not limited to the above embodiment as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by an appropriate combination of the plurality of components disclosed in the above-described embodiment. For example, some components of all the components shown in the embodiment may be deleted. In addition, components across different embodiments may be combined as appropriate.

1 Camera 2 Optical system 3 Image pickup element 4 Drive unit 5 System controller 6 Blur correction microcomputer 7 Angular velocity sensor 8 Accelerometer 9 Direction sensor 10 Memory 11 EVF
12 SW
13 GPS receiver 14 Communication unit 61 Reference value calculation unit 62, 63 Subtraction unit 64 Multiplication unit 65 Integration unit 66 Correction amount calculation unit 67 Communication unit 68 Direction detection unit 69 Attitude detection unit 6A Rotational offset calculation unit 6B Temporary storage unit 6C Coefficient Calculation unit 6D Coefficient holding unit 6E Multiplication unit 6A1 Vertical axis offset calculation unit 6A2 Horizontal axis offset calculation unit 6A3 Direction correction unit 6A4 Selector 101 Rotating device 102 Rotating unit 103 Rotating axis 611 Subtraction unit 612 Attitude fluctuation determination unit 613 Average value buffer Part 614 Reference value calculation part

Claims (12)

A first angular velocity sensor that detects the first angular velocity of the device including the optical system, and
A second angular velocity sensor that detects the angular velocity in the second rotation direction of the device, and
A gravity sensor that detects the direction of gravity with respect to the device, and
A posture detection unit that detects the posture of the device based on the gravity direction detected by the gravity sensor, and
Based on the latitude of the device, the first calculation unit that calculates the angular velocity of the rotational motion around the axis of rotation that occurs in the device due to the rotation of the earth as the first rotation offset amount.
Based on the latitude of the device and the orientation of the optical system in the optical axis direction, the angular velocity of the rotational motion generated in the device due to the rotation about the axis orthogonal to the vertical axis is the second. The second calculation unit that calculates the rotation offset amount of
When the posture detected by the posture detection unit is the first posture, the first rotation offset amount is subtracted from the angular velocity detected by the first angular velocity sensor, and the posture detected by the posture detection unit is the first. In the case of the posture of 2, the first subtraction unit that subtracts the second rotation offset amount from the angular velocity detected by the first angular velocity sensor, and
When the posture detected by the posture detection unit is the first posture, the second rotation offset amount is subtracted from the angular velocity detected by the second angular velocity sensor, and the posture detected by the posture detection unit is obtained. In the case of the second posture, a second subtraction unit that subtracts the first rotation offset amount from the angular velocity detected by the second angular velocity sensor, and
Equipped with
The rotation axis in the first rotation direction and the rotation axis in the second rotation direction are orthogonal to each other.
The first posture is a posture when the inclination of the rotation axis in the first rotation direction with respect to the axis in the vertical direction is within a predetermined angle range.
The second posture is a posture when the inclination of the rotation axis in the second rotation direction with respect to the axis in the vertical direction is within a predetermined angle range.
A blur correction device characterized by this. Based on the angular velocity detected by the first angular velocity sensor, a first determination unit for determining whether or not the attitude change in the first rotation direction of the apparatus has been continuously performed for a predetermined period, and a first determination unit.
Based on the angular velocity detected by the second angular velocity sensor, a second determination unit for determining whether or not the attitude change in the second rotation direction of the device has been continuously performed for the predetermined period, and a second determination unit.
A first reference value calculation unit that calculates a first reference value subtracted from the angular velocity detected by the first angular velocity sensor based on the determination result of the first determination unit.
A second reference value calculation unit that calculates a second reference value subtracted from the angular velocity detected by the second angular velocity sensor based on the determination result of the second determination unit.
Further prepare
When the first determination unit determines that the posture change in the first rotation direction of the device has not been continuously performed for the predetermined period, the first reference value calculation unit may use the first reference value calculation unit during the predetermined period. The first reference value is calculated based on the result of subtracting the first rotation offset amount or the second rotation offset amount from each of the angular velocities detected by the angular velocity sensor.
When the second determination unit determines that the posture change in the second rotation direction of the device has not been continuously performed for the predetermined period, the second reference value calculation unit may use the second reference value calculation unit during the predetermined period. The second reference value is calculated based on the result of subtracting the first rotation offset amount or the second rotation offset amount from each of the angular velocities detected by the angular velocity sensor.
The blur correction device according to claim 1. Further provided with an input unit for inputting the latitude of the device.
The blur correction device according to claim 1 or 2. Further provided with a selection unit for selecting the latitude of the device.
The blur correction device according to claim 1 or 2. Further provided with a latitude detection unit for detecting the latitude of the device.
The blur correction device according to claim 1 or 2. The latitude detection unit is a GPS receiving device.
The blur correction device according to claim 5. It also has a communication unit that communicates with external devices.
The communication unit receives the latitude of the device from the external device.
The blur correction device according to claim 1 or 2. Further, an orientation sensor for detecting the orientation in the optical axis direction of the optical system is provided.
The blur correction device according to any one of claims 1 to 7. A first correction coefficient calculation unit for calculating a first correction coefficient for correcting the angular velocity detected by the first angular velocity sensor, and a first correction coefficient calculation unit.
A second correction coefficient calculation unit for calculating a second correction coefficient for correcting the angular velocity detected by the second angular velocity sensor, and a second correction coefficient calculation unit.
Further prepare
In the first correction coefficient calculation unit, the rotation device is installed for the purpose that the rotation axis of the rotation unit included in the rotation device is parallel to the graticule, and the rotation axis of the rotation unit and the first rotation direction are provided. Based on the angular velocity detected by the first angular velocity sensor when the rotating device rotates the rotating portion after the blur correction device is fixed to the rotating portion for the purpose of being parallel to the rotating shaft of the To calculate the first correction coefficient,
In the second correction coefficient calculation unit, the rotation device is installed for the purpose of making the rotation axis of the rotation unit parallel to the graticule, and the rotation axis of the rotation unit and the rotation axis in the second rotation direction are installed. After the blur correction device is fixed to the rotating portion for the purpose of being parallel to each other, the first is based on the angular velocity detected by the second angular velocity sensor when the rotating device rotates the rotating portion. Calculate the correction factor of 2,
The blur correction device according to any one of claims 1 to 8, wherein the blur correction device is characterized. The device is an image pickup device provided with the blur correction device.
The blur correction device according to any one of claims 1 to 9, wherein the blur correction device is characterized. The first rotation direction is the Yaw direction.
The second rotation direction is the Pitch direction.
The blur correction device according to any one of claims 1 to 10. To detect the angular velocity in the first rotation direction of the device including the optical system,
To detect the angular velocity in the second rotation direction of the device,
Detecting the direction of gravity with respect to the device
To detect the posture of the device based on the detected gravity direction,
Based on the latitude of the device, the angular velocity of the rotational motion about the axis of rotation generated in the device due to the rotation of the earth is calculated as the first rotation offset amount.
Based on the latitude of the device and the orientation of the optical system in the optical axis direction, the angular velocity of the rotational motion generated in the device due to the rotation about the axis orthogonal to the vertical axis is the second. To calculate as the amount of rotation offset of
When the detected posture is the first posture, the first rotation offset amount is subtracted from the angular velocity in the first rotation direction, and when the detected posture is the second posture, the first posture is described. Subtracting the second rotation offset amount from the angular velocity in the rotation direction of 1.
When the detected posture is the first posture, the second rotation offset amount is subtracted from the angular velocity in the second rotation direction, and when the detected posture is the second posture, the second rotation offset amount is subtracted. Subtracting the first rotation offset amount from the angular velocity in the second rotation direction,
Including
The rotation axis in the first rotation direction and the rotation axis in the second rotation direction are orthogonal to each other.
The first posture is a posture when the inclination of the rotation axis in the first rotation direction with respect to the axis in the vertical direction is within a predetermined angle range.
The second posture is a posture when the inclination of the rotation axis in the second rotation direction with respect to the axis in the vertical direction is within a predetermined angle range.
A blur correction method characterized by this.

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