JP2791190B2 - Imaging device and image blur correction device - Google Patents

Description

The present invention relates to an imaging device such as a video camera and an image blur correction device.

2. Description of the Related Art In recent years, video cameras have been remarkably popularized with miniaturization, weight reduction, high magnification, and multifunctionalization.

In the above-described video camera, most of the functions relating to the photographing are automated, so that failure in photographing due to the function of the video camera itself is extremely reduced.

By the way, it is not an exaggeration to say that the screen is always blurred in the most used posture of the video camera,
In recent years, uncomfortable situations such as video sickness as well as image quality deterioration due to such screen shake have been considered as problems.

As a means for solving the above-mentioned image blur, there is a conventional image stabilizing device using a gyro mechanism.

In this apparatus, a lens barrel system is moved by a gyro mechanism to obtain a stable image. In this apparatus, there is a problem that the camera body becomes large and the weight increases.

Therefore, in recent years, an image formed by an optical axis decentering means such as a variable angle prism that positions an optical image on a predetermined image forming surface of an image pickup device by decentering the optical axis of a photographing optical system according to camera shake. An imaging device provided with a shake correction unit has been developed.

The above-described variable apex prism has a configuration in which a liquid having a constant refractive index is sealed in an accordion-shaped container having a bellows sandwiched between two transparent plates. Then, the photographic optical axis is decentered by controlling the tilt of the transparent plate on the subject side by a drive mechanism including a magnetic circuit.

As described above, in the above-described apparatus, since the optical axis is decentered from the variable apex prism, there is no need to move the lens barrel system, and it is possible to minimize an increase in size and weight of the camera body, A good image in which image blur is effectively prevented can be obtained.

[Problems to be Solved by the Invention] By the way, in the photographing apparatus provided with the image blur correcting means by the optical axis decentering means such as the variable apex prism described above, if the image blur correcting is disabled during the recording operation, the transparent plate The tilting state by the driving mechanism for driving the transparent plates is released, and a centering operation in which the two transparent plates become parallel due to the fluidity of the liquid sealed between the transparent plates occurs.

For this reason, the finder image may be discontinuous, giving the photographer a sense of incongruity.

The present invention has been made to solve the above-described conventional problems, and can perform image blur correction, and can also set the image blur correction to a non-operating state during a recording operation in which the image blur correction is activated. It is an object of the present invention to provide an imaging device capable of effectively preventing discontinuity of an image.

[Means for Solving the Problems] The present application has been made for the purpose of solving the above-mentioned problems, and according to the invention described in claim (1), an optical image on an image forming surface is formed. Imaging means for converting and outputting the image signal, recording means for recording the image signal output from the imaging means, blur detection means for detecting blur, and an image based on the blur based on the output of the blur detection means An image pickup apparatus comprising: a shake correcting unit that optically corrects the movement of the camera; and a control unit that holds a position at the time when the shake correcting unit is stopped during operation of the recording unit. .

According to the invention described in claim (2) of the present application, in the invention described in claim (1), the control means stops the recording operation of the recording means when the blur correction means is stopped. The image pickup apparatus is configured to release the holding of the stop position of the shake correction unit if the image is corrected.

Further, according to the invention described in claim (3) of the present application, an image forming means for forming an image, a shake detecting means for detecting a shake, and an image of the image due to the shake based on an output of the shake detecting means. A shake correcting means for correcting a movement, and a shake correcting operation by the shake correcting means is started when a shake detected by the shake detecting means is equal to or more than a predetermined value, and when the shake correcting means is stopped, the shake correcting When the moving amount of the means from the initial position is equal to or more than a predetermined value, the image blur correcting apparatus is provided with control means for returning to the initial position with a predetermined time constant.

Further, according to the invention described in claim (4) of the present application, in the invention described in claim (3), when the recording operation is stopped, the control means is irrespective of the movement amount from the initial position. The image blur correcting device is configured to return the blur correcting means to the initial position.

Further, according to the invention described in claim (5) of the present application, in the invention described in claim (4), the image blur correction device may be configured such that the initial position is a center position of a blur correction range of the blur correction unit. Features.

According to the invention described in claim (6) of the present application, in the invention described in claim (1), when the shake correcting means is stopped, the control means controls the movement of the shake correcting means after a lapse of a predetermined time. The imaging device is configured to release the holding of the stop position and to return to the initial position with a predetermined time constant.

[Operation] In the present invention, when the optical axis eccentric drive by the optical axis eccentric means is stopped during the operation of the recording means, the control means controls the optical axis eccentric means to maintain the optical axis eccentric position. , Image blur correction can be performed effectively,
Discontinuity of images can be effectively prevented even if the image blur correction is set to the non-operating state during the recording operation in which the image blur correction is activated.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram for explaining an imaging apparatus according to one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a variable angle prism (VAP), which is an optical axis decentering means, and reference numeral 2 denotes an imaging optical system having an imaging lens 2a including a focusing lens and a stop 2b. The drive of the imaging lens 2a is controlled by the focus drive circuit 3, and the stop 2b is driven by the iris drive circuit 4a and the iris control circuit 4b so that the amount of incident light on the imaging circuit system is controlled.

Reference numeral 5 denotes an image sensor CC that photoelectrically converts a subject image formed on an image plane by the imaging optical system 2 and converts the image into an image signal.
D and 6 perform predetermined processing such as gamma correction, blanking processing and addition of a synchronizing signal on the video signal amplified and output by a preamplifier (not shown) from the CCD 5 to convert it into a standardized standard television signal. , A camera process circuit that outputs from a video output terminal. The television signal output from the camera process circuit 6 is output to a video recorder (not shown) and is also supplied to a monitor 7 such as an electronic viewfinder.

Reference numeral 8 denotes a blur width detection circuit that detects a blur width of an object image (width of an edge portion of the object image) from a video signal output from the CCD 5, and uses a characteristic that the blur width of the object decreases as the focus state is approached. To perform focus detection.

Reference numeral 9 denotes a control circuit configured by, for example, a microcomputer that controls the entire system, and includes an I / O port, an A / D
It consists of a converter, ROM, and RAM. This control circuit 9
Captures the blur width information output from the blur width detection circuit 8 and the peak value information of the high frequency component from a band-pass filter (not shown) so that the blur width in one field period of the video is minimized, A predetermined drive control signal is output to the focus drive circuit 3 to drive the above-described imaging lens 2a so that the peak value of the high-frequency component becomes maximum. The control circuit 9 receives a detection signal from a shake detection sensor 10 for detecting a shake amount of a video camera body as an imaging device, and outputs a light according to a shake amount based on the detection signal and an operation mode of the video camera body. A correction signal for correcting the axis is output to the VAP drive circuit 11. As a result, the VAP drive circuit 11 places the imaging optical system 2 at a predetermined position on the imaging surface of the CCD 5.
The optical axis is decentered by tilting the VAP1 so that an optical image from is formed.

Next, the details of the variable apex angle prism (VAP) 1, the shake detection sensor 10, and the VAP drive circuit 11 will be described with reference to FIG.

As shown in FIG. 1, the shake detection sensor 10 has a cylindrical case 12 filled with a liquid 13 having a predetermined refractive index.
In this liquid 13, a floating body rotatable around a predetermined rotation axis
14 is provided. The floating body 14 is held at a predetermined position by a closed magnetic circuit constituted by a permanent magnet 15 provided so as to surround the case 12 when there is no blur. When the video camera body shakes and the floating body 14 rotates relative to the case 12, the signal light from the light emitting element 16 is reflected on the surface of the floating body 14 and is incident on the light receiving element 17 for position detection. It has become so. Therefore, the incident position of light on the light receiving element 17 changes depending on the position of the floating body 14, and the output signal changes. Light receiving element
The output signal from 17 is output to the above-described control circuit 9 via the position detection circuit 18.

On the other hand, the variable apex angle prism 1 is an accordion-shaped container 22 having a bellows sandwiched between two transparent plates 21a and 21b.
Is filled with a liquid 23 having a certain refractive index. The variable apex angle prism 1 is disposed on the front side of the imaging optical system 2 and the CCD 5 and has the above-described shake detection sensor 10.
The magnetic circuit 24 is driven by the VAP drive circuit 11 controlled by the control circuit 9 in accordance with the output of the side position detection circuit 18, and the transparent plate 21a of the variable apex angle prism 1 on the object side is tilted. The amount of tilt of the transparent plate 21a is detected by the detecting devices 25 and 26, and the output signal is sent to the control circuit 9 via the position detecting circuit 27.
Is output to In the control circuit 9, the shake detection sensor
The VAP drive circuit 11 is controlled so that the magnetic circuit 24 is driven by controlling the VAP drive circuit 11 so that the difference between the output of the position detection circuit 18 on the 10 side and the output of the position detection circuit 27 on the variable apex angle prism 1 becomes “0”. The first transparent plate 21a is tilted.

Next, the operation of the above-described control circuit 9, which is a feature of the image pickup apparatus of the present invention, will be described with reference to the flowcharts of FIGS.

By the way, the variable apex angle prism which is an optical axis decentering means used for the video camera which is the imaging device of the invention turns on and off the anti-vibration function when the video camera is in the full auto mode and at the will of the photographer. It can be used in the manual mode where it can be used.

First, as shown in FIG. 3, when the video camera is in the full auto mode, it is confirmed whether or not the video camera is in the REC pause state (step 1). In the REC pause state, it is confirmed whether the output signal from the shake detection sensor 10 has exceeded a predetermined value (step 2), and if it has exceeded the predetermined value, the variable apex angle prism 1 is activated (step 3).
Next, it is confirmed whether or not the REC state is established (step 4).
In this state, the image stabilization function operation recording state in which the variable apex angle prism 1 is operated is set. If it is not in the REC state, it is checked whether it is in the REC pause state (step 5). If it is in the REC pause state, the process returns to step 2. When the REC pause state is not set, the tilt position of the transparent plate 21a of the variable apex angle prism 1 that decenters the optical axis based on a predetermined time constant is gradually shifted to the centering position where the transparent plates 21a and 21b are parallel. After returning, the centering is performed (step 6). When the centering is completed, the image stabilizing function is turned off (step 7).

On the other hand, when the output signal from the shake detection sensor 10 is equal to or smaller than the predetermined value in step 2, the tilt position of the variable apex angle prism 1 is temporarily held (step 8), and then the transparent plate 21a of the variable apex angle prism 1 is held. It is confirmed whether or not the tilt position is shifted from the center by a predetermined value or more (step 9).
If it is deviated, the tilting position of the transparent plate 21a of the variable apex angle prism 1 that decenters the optical axis is gradually returned to the centering position where the transparent plates 21a and 21b are parallel based on a predetermined time constant. And centering (step 10)
When the centering is completed, the process returns to step 1.

Therefore, in the full auto mode of the video camera, when the video camera body touches a predetermined value or more due to, for example, camera shake in an REC pause state in which the optical image from the imaging optical system is output to the monitor 7 serving as a viewfinder, When the anti-vibration function is activated and the anti-vibration function is not required when, for example, the camera shake is eliminated, the tilting position of the transparent plate 21a of the variable apex angle prism 1 is temporarily held, and then the centering operation is gradually performed. Done. Thus, even when the switching state between the operation and non-operation of the image stabilizing function occurs, the image from the monitor 7 serving as the viewfinder does not suddenly change in the optical axis, and the image of the variable apex angle prism 1 is gradually changed. Since the centering operation is performed, the photographer does not feel uncomfortable.

Next, the case of the manual mode of the image stabilizing function will be described with reference to the flowchart of FIG.

As shown in the figure, first, it is confirmed whether or not the image stabilization function is selected (step 11). When the image stabilization mode is selected, it is checked whether or not the camera is in the REC pause state (step 12). ). If it is in the REC pause state, the image stabilization function is activated (step 13). Next, it is confirmed whether or not the anti-shake function has been turned off (step 14).
It is confirmed whether or not it is in the middle (step 15). During REC, the tilt position of the transparent plate 21a of the variable apex angle prism 1 is temporarily held by driving the magnetic circuit 24 (step 16).
Thereafter, it is confirmed whether or not the REC pause state is established (step 17). If the REC pause state is not reached, it is confirmed whether or not the tilt position of the transparent plate 21a of the variable apex angle prism 1 is shifted from the center by a predetermined value or more (step 17). Step 18) If there is a deviation, the tilt position of the transparent plate 21a of the variable apex angle prism 1 that decenters the optical axis is determined based on a predetermined time constant.
Centering is performed by gradually returning to the centering position where 1a and 21b are parallel (step 19).

Therefore, even in the manual mode of the anti-vibration function,
Even if the switching state between the operation and non-operation of the anti-vibration function occurs,
Since the centering operation of the variable apex prism 1 is performed on the image from the monitor 7 which is a viewfinder without a sudden change in the optical axis, the photographer does not feel uncomfortable.

As described above, in the above-described embodiment, the image blur due to the camera shake can be effectively corrected, and even if the operation of switching between the operation state and the non-operation state of the image blur correction function, which is the image stabilization function, is performed, the finder is provided. The discontinuity of the monitor image is effectively prevented.

Note that, in the above-described embodiment, an example using a so-called TV-AF that detects a blur width of a subject image from a video signal output from the CCD 5 and performs focus detection using the property that the blur width is reduced. As described above, the present embodiment can be applied to an active AF including light emitting and light receiving elements.

Further, in the above-described embodiment, the example in which the image blur correction mechanism is provided integrally with the video camera as the imaging device has been described. However, the variable apex angle prism, the blur detection sensor, the VAP drive circuit, and the control circuit are configured separately. The adapter may be detachable from the video camera main body, and the control circuit may be configured to be shared with the video camera main body.

[Effects of the Invention] As described above, in the imaging apparatus of the present invention, image blur correction can be performed effectively, and image blur correction is set to a non-operating state during a recording operation in which image blur correction is activated. Also, it is possible to effectively prevent discontinuity of a monitor image serving as a finder.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an image pickup apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram for explaining details of a variable apex angle prism, a shake detection sensor, and a VAP drive circuit in FIG. FIGS. 3 and 4 are flowcharts for explaining the operation of the control circuit. 1 ... variable apex angle prism 2 ... imaging optical system 5 ... CC
D, 7 monitor, 9 control circuit, 10 shake detection sensor, 11 VAP drive circuit, 21a, 21b transparent plate, 24
... magnetic circuit.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N 5/225-5/232

Claims (6)

(57) [Claims] 1. An image pickup means for converting an optical image on an image forming surface into an image signal and outputting the image signal, a recording means for recording an image signal output from the image pickup means, a blur detection means for detecting blur, A blur correcting means for optically correcting the motion of the image due to the blur based on an output of the blur detecting means; and a stop position when the blur correcting means is stopped during operation of the recording means. An imaging apparatus, comprising: 2. The control device according to claim 1, wherein
An imaging apparatus characterized in that when the blur correcting means is stopped, if the recording operation of the recording means is stopped, the holding of the stop position of the blur correcting means is released. 3. An image forming means for forming an image, a blur detecting means for detecting blur, a blur correcting means for correcting an image movement caused by the blur based on an output of the blur detecting means, When the blur detected by the detecting means is equal to or more than a predetermined value, the blur correcting operation by the blur correcting means is started, and when the blur correcting means is stopped, the movement amount of the blur correcting means from the initial position is a predetermined value. Control means for returning to the initial position with a predetermined time constant in the case described above. 4. The control device according to claim 3, wherein:
An image blur correction device, wherein when the recording operation is stopped, the blur correction means is returned to the initial position regardless of the movement amount from the initial position. 5. The image blur correction device according to claim 4, wherein the initial position is a center position of a blur correction range of the blur correction means. 6. The control device according to claim 1, wherein the control unit is configured to stop when the shake correction unit is stopped.
An imaging apparatus configured to release the holding of the stop position of the shake correction unit after a predetermined time has elapsed, and to return to the initial position with a predetermined time constant.