JPH03248136A - Picture blurring detector for camera - Google Patents

Abstract

PURPOSE:To obtain sufficient detection accuracy regardless of the length of a lens barrel by providing an arithmetic means calculating a picture blurring quantity based on outputs from first to fourth acceleration sensor outputs and constant. CONSTITUTION:A first to a fourth acceleration sensors 19a - 19d are connected to a CPU 46 as the arithmetic means through amplifying circuits 31, 32, 41 and 42 and A/D converting circuits 33, 34, 43 and 44, respectively. Hence, A/D converting values corresponding to accelerations are inputted to the CPU 46. A memory 35 stores constants consisting of values corresponding to distances in the optical axis L direction of the first and third acceleration sensors 19a and 19c and the second and fourth acceleration sensors 19b and 19d, the program of the CPU 46 for calculating the necessary moving amount of blurring correcting optical elements 8 and 6 from the outputs from the acceleration sensors 19a - 19d, and sensitivity correcting coefficients for correcting errors arising from variance based on the values of the first and second acceleration sensors 19a and 19b, etc. Thus, the picture blurring quantity of a camera can be detected with necessary detecting accuracy corresponding to difference in the focul distance of photographic lens, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting image blur in a camera that occurs during photographing, and an image blur prevention device.

[Conventional technology]

Regarding the detection and prevention of camera image blur, several means have been proposed in the past.

For example, Japanese Patent Laid-Open No. 125923/1983 discloses that at least two acceleration sensors are disposed within the camera body, and the amount of image blur of the camera is detected based on the outputs of the acceleration sensors.

Further, Japanese Patent Laid-Open No. 150580/1983 discloses a device that prevents image blur using outputs from two angular velocity sensors that rotate integrally with the camera body.

[Problem to be solved by the invention]

As shown in Japanese Patent Application Laid-Open No. 63-125923, in a camera that uses an acceleration sensor disposed inside the camera body,
The distance between the sensors cannot be set very large.As is well known, the phenomenon of image blur during photography is more susceptible to this blur angle as the focal length of the photographic lens becomes longer.
Although it is necessary to improve detection accuracy, there is a limit to the improvement in detection accuracy when the sensor is disposed inside the camera body as described above.

Further, as shown in Japanese Patent Laid-Open No. 150580/1983, in the case of using an angular velocity sensor, the accuracy of the angular velocity sensor itself is not very good, and it cannot be used to detect image blur when a long focal length lens is used.

The present invention has been made in view of the above-mentioned viewpoints, and is intended to enable detection and prevention of image blur with sufficient accuracy even when photographing using a long focal length lens.

(Means and Effects for Solving the Problems) In order to solve the above problems, the present invention provides a lens that is disposed near the tip of the photographic lens and has a sensitivity axis in a first direction perpendicular to the optical axis of the photographic lens. a second acceleration sensor disposed near the tip of the photographing lens and having a sensitivity axis in a second direction orthogonal to both the optical axis of the photographing lens and the first direction; and a camera. a third acceleration sensor disposed on the camera body and having a sensitivity axis parallel to the first direction; a fourth acceleration sensor disposed on the camera body and having a sensitivity axis parallel to the second direction; Disposed within the photographic lens, a constant corresponding to the distance between the first acceleration sensor and the third acceleration sensor in the optical axis direction and the distance between the second acceleration sensor and the fourth acceleration sensor in the optical axis direction is stored. By providing the first memory means and the calculation means for calculating the amount of image blur based on the outputs of the first to fourth acceleration sensors and the constants, it is possible to determine the focal length of the lens, that is, the length of the lens barrel. It is designed so that sufficient detection accuracy can be obtained even if the

Furthermore, by providing a blur correction optical element that operates based on the output of the calculation means, image blur can be prevented.

〔Example〕

1 to 5 show a first embodiment of the present invention.

As is well known, a photographing lens 2 is detachably attached to the camera body 1. In addition, in the following explanation, as shown in FIG. 2, the X axis.

The Y axis and the Z axis are the longitudinal direction of the camera body, the vertical direction of the camera body, and the optical axis direction of the photographic lens, respectively.

The photographing lens 2 has a photographing lens optical system 3, and a first acceleration sensor 19a and a second acceleration sensor 19b are disposed at the tip thereof above and below the optical axis of the lens. The first acceleration sensor 19a has a sensitivity axis in the Y-axis direction, and the second acceleration sensor 19b is a known piezoelectric acceleration sensor having a sensitivity axis in the X-axis direction. It is shown. The first image stabilizing optical element 8, which is made of a parallel plane plate, is rotatably held on the lens barrel fixing part by a shaft 10a. Above axis 1
A disk-type ultrasonic motor 12 is connected to 0a, and receives an output from an electric circuit 20 to rotate the optical element 8 to correct angular deviation in the YZ plane.

Further, a drum 14a is provided on the shaft 10a,
A magnetic encoder 14 is configured in cooperation with the magnetic sensor 14b.

A second image stabilizing optical element 9 consisting of a parallel plane plate has an axis 11
It is rotatably held on the lens barrel fixing part by a. A disk type ultrasonic motor 13 is connected to the shaft 11a, and receives an output from an electric circuit 20 to drive the optical element 9.
is rotated to correct angular shake in the XZ plane.

Further, a drum 15a is provided on the shaft 11a,
A magnetic encoder 15 is configured in cooperation with the magnetic sensor 15b.

On the other hand, a third acceleration sensor 19c having a sensitivity axis in the Y-axis direction, a fourth acceleration sensor 19d having a sensitivity axis in the X-axis direction, and an electric circuit 18 are provided within the camera body. Further, the lens-side electric circuit 20 and the camera body-side electric circuit 18 are connected to each other via a connector 1617 provided on the mounting surface of the lens.

The reference numeral 4 is a rotating mirror, 5 is a shutter, 6 is a pentaprism, and 7 is an eyepiece lens, which are well-known.

The lens side electric circuit 20 and the camera body side electric circuit 1
8 is constructed as shown in FIG.

That is, the first to fourth acceleration sensors 19a to
19d are amplifier circuits 31, 32, 41, 42, respectively. and A/D conversion circuits 33, 34, 43, and 44, and are connected to a CPU 46 as a calculation means. That is, the A/D conversion value of the voltage signal corresponding to each acceleration is manually input to the CPU 46. Drive circuits 36 and 37 drive the ultrasonic motors 12 and 13 in accordance with commands from the CPU 46 and outputs from the magnetic encoders 14 and 15, respectively.

Image stabilization optical element 8 using this ultrasonic motor 12.13
．． The rotation amount of 9 is transmitted to the drive circuit 36.37 via the magnetic encoder 12.13.

A memo 1,135 as a first memory means is composed of a suitable electrical storage means such as a ROM, and the first acceleration sensor 1
9a, third acceleration sensor 19c, and second acceleration sensor 19
b and the distance between the fourth acceleration sensor 19d in the optical axis direction (the fourth
1!1 A constant consisting of a value corresponding to the distance between the OACs), a program for the CPU 46 that calculates the required movement amount of the shake correction optical element 8.9 from the output of each acceleration sensor 19a to 19d, and the first and second acceleration sensors. Sensitivity correction coefficients and the like for correcting errors due to variations in signals 19a and 19b are stored. Further, the memory 45 serving as the second memory means includes third and fourth acceleration sensors 19c.

Sensitivity correction coefficients etc. of 19d are stored.

Here, before going into the explanation of the operation of the embodiment, a method for calculating the angular acceleration of angular shake from a set of two acceleration sensors will be explained in detail. FIG. 4 shows the second and fourth acceleration sensors 19b that calculate the angular velocity of the angular shake in the XZ plane.
, 19d are projected onto the xZ plane. A,
B are second and fourth acceleration sensors 19b, respectively.

19d is the sensing point, and 0 is the rotation center of the angular shake. A' and B' are points obtained by orthogonally projecting 1A and B onto a straight line passing through 0 and parallel to the optical axis of the photographing lens. Further, C is the intersection of a straight line passing through A and parallel to the optical axis of the photographing lens and a straight line passing through B and perpendicular to the optical axis of the photographing lens and within the plane of illustration. The angular acceleration of the angular shake is α, and the acceleration hectors at this time are a, b, a, b'', respectively, and the orthogonal projection of a onto the straight line AA'' is the straight line BB of Peltor a' b.
'Upward orthogonal projection vector b' Angle A' OA 01.
Let angle B' OB be θ.

In this case, "" a CO5 θ 1 Therefore θ 3 1 a Also, from a'//a', a' = a# -・-11------
−−−− ■Similarly, for b′, b′ wealth b ′ −−−−−−−−−−−・− ■Formula■
．． The second acceleration sensor 19b and the fourth acceleration sensor 19d are connected to A'. It can be seen that the output is the same whether it is placed at position B'' or whether it is placed at positions A or B.

Also, since a'// b', a'-b' l l a-b・
-------1... ■ However, L (A'.B#) is the length between A' and B'.

That is, the outputs of the second and fourth acceleration sensors 19b19d are set as az and am, respectively, and the second and fourth
The distance of the acceleration sensors 19b and 19d in the optical axis direction of the photographing lens (corresponding to AC in FIG. 4), that is, the distance L(A",
If B'') is L-za, it becomes from ■.

As is clear from Fig. 4, even if α is the same, Lza
is large, then a. And a4 will also be larger. At this time, if the errors included in az and aa are each constant values, L. The larger the value, the higher the calculation accuracy of α.

In other words, even if the accuracy of the acceleration sensor has a certain detection limit, if the acceleration sensor is installed as in this example, the overall length of a long focal length lens, which is susceptible to angular shake, will generally be longer and Lxa will be increased. As the angle becomes larger, the detection accuracy of the acceleration α of the angular shake becomes higher.

The above is exactly the same regarding angular blur within the YZ plane.

Based on the above, the operation of this embodiment will be explained with reference to FIG.

First, when the camera tfA switch (not shown) is turned on, the CP
U46 adds + and kg to the sensitivity correction coefficients of the first and second acceleration sensors 19a and 19b stored in the memory 35 in the lens, and also adds + and kg to the sensitivity correction coefficients of the first and second acceleration sensors 19a and 19b stored in the memory 35 in the lens, and Acceleration sensor 19c, 19d
The CPU 46 reads out 4 as the sensitivity correction coefficient and 4 (F2), and then the CPU 46 reads a constant consisting of a value corresponding to the distance in the optical axis direction between the first and third acceleration sensors 19a and 19c from the memory 35 in the lens. ,,,second and fourth
A constant consisting of a value corresponding to the distance in the optical axis direction between the acceleration sensors 19b and 19d. 4 (F3), and further converts the angles of angular shake in the YZ plane and in the XZ plane to be calculated into angular velocities to be rotated of the first and second shake correction optical elements 8 and 9-, respectively. Formula F+s
(w) and Fz4(W) from the memory 35 (
F4), this F13 (W), Fta (w)
For example, Nitsuite is 1 d.

It can be done.

Here, d+ and d□ are the first . The thickness of the second image stabilizing optical element, β is the photographing magnification, and f is the focal length of the photographic lens.

This means that the amount of image movement δ due to camera tilt is δ-(1-β)f・θ when the tilt angle is θ, and δ--dsinθ(Jn"-5in"θ-cosθ)/
n (n: refractive index), and if θ is sufficiently large, then δ snow −dsin θ.

Next, the shutter performs an opening operation (F5), and the CPU 46
reads the accelerations a1 to a output from the first to fourth acceleration sensors 19a to 19d (F6). At this time, the CPU
46 is the acceleration corrected for the sensitivity error of the acceleration sensor, 1 to . +, a+ ''' K+ 'a1+ ''
-------'-' + am "" Ka, calculated by the formula a4 (F7). Next, the angular acceleration α11 of the angular shake in the YZ plane and the XZ plane. α is calculated by each (F8), and then the angular acceleration W, 3 and W□ are calculated by time integration (F9). This uses the acceleration sampling period ts as W+s=α+s ts , Wza=C
It may also be tza tS. Next, the angular velocity wl at which the first and second shake correction optical elements 8 and 9 should be rotated,
H3 = 1 + J = F 11 (WB2), H2 = F2J
Calculated by (W24) (FIO). Above angular velocity -1
, -: by sending the values to the drive circuits 36 and 37, the first and second image stabilization optical elements are rotated via the ultrasonic motor 2.13 to correct image blur corresponding to angular blur. (Fil), and the flow from F6 to Fll is repeated until the shutter closes, and when the shutter closes, the above operation is completed (F12 to F13). Since the first and second acceleration sensors are provided,
A long focal length lens with a longer overall length of the photographic lens has a longer distance in the optical axis direction from the third and fourth angle sensors, making it easier to obtain accurate detected angular velocity. Second, since the sensitivity correction coefficients of each of the first to fourth acceleration sensors are stored in the closest lens or camera body, which camera body and photographic lens are combined with each other, However, the influence of sensitivity errors of each acceleration sensor can be removed. Thirdly, there are two 1&
A constant L13 corresponding to the distance between the acceleration sensors of lI.
Since L24 is stored, the angular acceleration can be calculated simply by reading this value. Fourthly, since the photographing lens stores a mathematical formula that makes the angular velocity calculated from the angular acceleration correspond to the angular velocity to be applied to the blur correction optical element, optimal blur correction can be performed.

In this example, a single focus lens was described, but in the case of a zoom lens or a macro lens where the state of the optical system or the distance between the two acceleration sensors changes, it is possible to A formula for calculating the interval in the optical axis direction of a certain acceleration sensor or the angular velocity at which the shake correction optical element should be rotated may be output variably using an encoder or a combination of an encoder and a memory. It may be placed inside the teleconverter or in a teleconverter separate from the lens, and other correction methods may be used, such as swinging the lens group perpendicular to the optical axis.

Next, a second embodiment of the present invention will be described based on FIGS. 6 to 8. Note that the same members as those in the first embodiment are given the same reference numerals.
Details are omitted.

This embodiment differs from the image stabilization optical system 8 in the first embodiment.
9 and magnetic encoder 14.15, ultrasonic motor 12.
13 is removed and a sounding body is provided as a warning means instead. In other words, there is a PCv inside the camera body 1.
A sounding body 22 such as the above is disposed. Further, the electric circuit 20' in the photographing lens and the electric circuit 18' in the camera body are constructed as shown in FIG. That is, the in-lens electric circuit 20'
A CPU 3O as a calculation means is disposed inside. This CPUa8 includes first and second acceleration sensors 19a,
Output from 19b and memo IJ as first memory means
It receives the output from 35 and performs arithmetic operations, and also communicates with the CPU 46 on the camera body side.

The memory 35 stores the same constants, sensitivity correction coefficients, and program parameters as in the first embodiment, as well as a limit angular shake amount.

Further, the CPUs 38 and 46 are connected by a transmission permission signal line 46a of the CPU 38 outputted by the CPU 46, a bidirectional communication timing line 46b, and a bidirectional communication data line 46c.

Next, while referring to the flowchart in FIG.
The operation of the second embodiment will be explained focusing on the operation No. 6.

In this embodiment, the CPU 46 determines whether the magnitude of blurring during exposure exceeds an allowable amount, and when the amount exceeds the allowable amount, a warning buzzer 22 sounds to prompt re-photographing. In FIG. 8, the flow from F1 to F3 is the same as that of the first embodiment shown in FIG. All CPtJ via CPU38
46. On the other hand, when it is determined at F5 that the shirt ivy is open, the acceleration signals ai,=ai are output from the first to fourth acceleration sensors.

(F6), and perform acceleration signal correction (F6) as in the first embodiment.
F7), camera shake angular acceleration calculation cry3= (a+
' , ~ai' ) /Lart4= (ai'
The camera shake angular velocity Wi+s, Wizm is calculated (F21) via z ~ ai' a ) /Lza (F8), where the subscript i indicates the first sampling after the shutter is opened. Here, in this embodiment, the angular velocities W i l 3 and w i, , are further integrated over time, and the camera shake angles θt+s and θi
xa is calculated (F22), and the cumulative camera shake angle θ 1+3 + θ′i! from the shutter opening is calculated. 4 calculation θ′1
1. -Σθit! , θ'iea −Σθ1ta(F
23), the flow from F6 to F23 is repeated until the shutter closes (F12), and after the shutter is opened, the maximum point of cumulative camera shake (θ5aXtzθl1aXi4) is selected (θl1aX++, θmaXta) = (θi
' 1. θi'xa> MAX (θiI
3! +θjz, 2) is performed (F24), when this point and the point at the start of exposure are farther apart than the limit angular shake amount ψ (θ@aX+s”+θαaxz4”) > At ψ2, the camera shake has exceeded the allowable range. If the limit is exceeded, a warning buzzer will sound. (F25.F26).

As an effect of the second embodiment, the photographer is able to accurately determine whether the camera shake exceeds the allowable range, regardless of variations in sensitivity of the photographic lens attached to the camera body or the built-in acceleration sensor.

Further, the warning may be a visual one such as a flashing LED or a message on a display other than a sound.

Next, a third embodiment of the present invention will be described based on FIGS. 9 and 10.

In FIG. 9, an ordinary lens 21 having no electric circuit, lens contacts, etc. is attached to the camera body 1.

Note that the reference numeral 23 is a release button.

Originally, the camera body l can reduce the amount of angular shake by combining it with the photographing lens 2 or 2#, which has first and second acceleration sensors, electric circuits, lens contacts, etc., as shown in the first and second embodiments. can be detected with high accuracy. However, especially in single-lens reflex cameras, various lenses may be attached, and a normal photographic lens of 2" as mentioned above may be used. In this case, Although it is difficult to accurately detect angular shake that has a large effect on image blur using only the third and fourth acceleration sensors 19c and 19d, in general, it is difficult to accurately detect angular shake and the third and fourth acceleration sensors 19c and 19d.
It is clear that the correlation with the outputs of 9c and 19d is strong.

In this embodiment, in consideration of the above-mentioned situation, when a photographic lens without an acceleration sensor is attached to the camera body 1, the output of the acceleration sensor inside the camera body 1 is used to warn of camera shake and to release the shutter. The mode has been changed to prevent large photos.

The operation of the third embodiment will be explained with reference to FIG. 10. First, from the memory 45 in the camera body, the sensitivity correction coefficients of the third and fourth acceleration sensors 19c and 19d are stored.
4 in F2) and the same memory 4
5 is read out (F4'').

After that, when the release button 23 is pressed and a release signal is input (F31), the acceleration signal a i! from the third and fourth acceleration sensors. , Load a ia (F6)
, correction of the acceleration signal a 'r'' -, a i3゜a
Perform 4ai4 on l' a = (FT), and calculate the displacement of camera shake through two time integrations (F21
', F22'), the cumulative value zi', xΣ
xis, xi' - ΣXi4 is calculated (F23
M. Repeat this operation from F6 to F231 until just before the cane is opened, that is, until the end of the so-called release time lag (F32). When the release time lag approaches the end, calculate the maximum cumulative camera shake displacement ( X l1aX3, X 118m4)
−(Xis, xia)w+ax (xi'
, "10 x Bi,") (F24"), and determine whether the blur value at that time is larger than the limit blur amount x0 (x maxx" + x11aX4") > x
o"? (F25"). If the camera shake exceeds the limit, the release lock is applied, the exposure is canceled (F34), and a buzzer sounds (F26'').
, if the camera shake does not exceed the limit, exposure is performed (F33).

In the third embodiment, the camera shake that will occur during exposure is estimated from the output of the acceleration sensor inside the camera body l during the release time lag, and the camera shake that will occur during exposure is estimated.
Photographs with a lot of image blur can be prevented only by using the camera body l as used in the embodiment.

In the third embodiment, it is even more effective to change the limit amount of blur x0 according to the focal length and shape of the attached lens. Xo may be switched by automatically inputting it with the identification means. Also, a warning of camera shake during exposure may be issued as in the second embodiment, and a warning or release lock may be issued based on acceleration detection during the release time lag. It may be incorporated into the first and second embodiments.

〔Effect of the invention〕

As described above, according to the present invention, the amount of image blur of a camera can be detected with the necessary detection accuracy depending on the difference in focal length of the photographic lens. It also enables highly accurate detection that is not affected by sensor sensitivity errors.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the first embodiment of the present invention, Fig. 2 is a perspective view of the same as above, Fig. 3 is a circuit block diagram of the first embodiment, and Fig. 4 is a diagram showing the principle of the first embodiment. , FIG. 5 is a flowchart of the first embodiment, FIG. 6 is a sectional view showing the second embodiment of the present invention, FIG. 7 is a circuit block diagram of the second embodiment, and FIG. 8 is a second embodiment. FIG. 9 is a sectional view showing a third embodiment of the present invention, and FIG. 10 is a flow chart of the third embodiment. 1 ・・・−・−Camera body 2 ・・・−・−・−Photographing lens 8! l-1 --- Shake correction optical element 19a --- First acceleration sensor 19b --- Second acceleration sensor 19c --- Third acceleration sensor 19d --- Fourth acceleration sensor 35, 45-1 ...Memory means 38, 46--Arithmetic means

Claims (4)

[Claims] (1) In a camera image blur detection device consisting of a camera body and a lens attached to the camera body, the sensor is disposed near the tip of the photographic lens and is sensitive in a first direction orthogonal to the optical axis of the photographic lens. a first acceleration sensor having an axis; and a second acceleration sensor disposed near the tip of the photographing lens and having a sensitivity axis in a second direction orthogonal to both the optical axis of the photographing lens and the first direction. a third acceleration sensor disposed on the camera body and having a sensitivity axis parallel to the first direction; and a fourth acceleration sensor disposed on the camera body and having a sensitivity axis parallel to the second direction. and a constant that is disposed within the photographic lens and corresponds to the distance between the first acceleration sensor and the third acceleration sensor in the optical axis direction and the distance between the second acceleration sensor and the fourth acceleration sensor in the optical axis direction. An image blur detection device for a camera, comprising: a first memory means for storing the stored information; and a calculation means for calculating an amount of image blur based on the outputs of the first to fourth acceleration sensors and the constant. (2) In the image blur detection device for a camera according to claim 1, the first memory means further stores a correction coefficient associated with a sensitivity error of the first and second acceleration sensors, The camera body is provided with a second memory means that stores correction coefficients associated with sensitivity errors of the third and fourth acceleration sensors, and the calculation means calculates the amount of image blur of the camera based on the correction coefficients. An image blur detection device for a camera, characterized in that it corrects image blur. (3) The image blur detection device for a camera according to claim 1 further includes means for determining whether or not the amount of image blur is within a permissible value, and a warning activated based on the output of the determination means. An image blur detection device for a camera, comprising: means. (4) In a camera image stabilization device consisting of a camera body and a photographic lens attached to the camera body, an image stabilization device disposed near the tip of the photographic lens and directed in a first direction perpendicular to the optical axis of the photographic lens. a first acceleration sensor having a sensitivity axis; and a second acceleration sensor disposed near the tip of the photographing lens and having a sensitivity axis in a second direction perpendicular to both the photographing lens optical axis and the first direction. a third acceleration sensor disposed on the camera body and having a sensitivity axis parallel to the first direction; and a fourth acceleration sensor disposed on the camera body and having a sensitivity axis parallel to the second direction. and a constant that is disposed within the photographic lens and corresponds to the distance between the first acceleration sensor and the third acceleration sensor in the optical axis direction and the distance between the second acceleration sensor and the fourth acceleration sensor in the optical axis direction. a first memory means for storing the information; a calculation means for calculating the amount of image blur based on the outputs of the first to fourth acceleration sensors and the constant; and a blur correction optical element that operates based on the output of the calculation means; An image stabilization device for a camera, characterized by comprising: