JPH04215627A - Imaging device - Google Patents

Abstract

PURPOSE:To prevent an image jiggle when the jiggle detection output is unstable by preventing the image display until the output of a jiggle detecting means detecting the jiggle of an image pickup device is stabilized after a power source is turned on. CONSTITUTION:A control circuit 9 prevents the output of a camera processor circuit 6 converting the signal from a CCD 5, i.e., an image pickup means, from being sent to a monitor 7, i.e., an image display section, until the output of a jiggle detecting sensor 10, i.e., a jiggle detecting means, is stabilized after the sensor 10 is operated.

Description

[Detailed description of the invention]

0001

FIELD OF APPLICATION OF THE INVENTION The present invention detects the amount of shake of the main body of an imaging device, and based on this detection ability, decenters the optical axis so that the optical image is always positioned at a predetermined position on the imaging plane of the imaging means. The present invention relates to improvement of an imaging device such as a video camera having a shake correction function.

0002

BACKGROUND OF THE INVENTION In recent years, video cameras have become increasingly popular as they become smaller, lighter, have higher magnification, and become more multifunctional. Furthermore, since most of the functions related to photography are automated, there are extremely few failures in photography due to the functions of the video camera itself.

By the way, when taking pictures with a video camera, most of the time it is held in hand, and it is no exaggeration to say that in such a position the screen is always shaken, resulting in a decrease in image quality. In addition, unpleasant situations such as video sickness have become a problem in recent years.

In view of this point, an image stabilizing device using a gyro mechanism has been proposed as a device to eliminate the above-mentioned screen shake.

[0005] This device attempts to obtain a stable image by moving the lens barrel system using a gyro mechanism, but it has the disadvantage that the camera body becomes larger and the weight increases. Ta.

Therefore, in recent years, optical axis decentering means such as a variable apex prism has been developed, which decenters the optical axis of the photographic optical system according to camera shake to position an optical image on a predetermined imaging plane of an image sensor. Imaging devices equipped with this technology have been developed.

For example, the variable apex angle prism described above has a structure in which a liquid having a constant refractive index is sealed inside an accordion-shaped container having a bellows sandwiched between two transparent plates. Based on the shake information obtained by the detection means, the transparent plate on the subject side is tilted and controlled by a drive mechanism consisting of a magnetic circuit, thereby decentering the photographing optical axis and correcting the shake.

[0008] In this way, the above-mentioned image blur correction means is configured to decenter the optical axis using, for example, a variable apex angle prism, so there is no need to move the lens barrel system.
The increase in size and weight of the camera body can be minimized, and good images with image shake effectively prevented can be obtained.

However, with the above-mentioned means, it often takes time for the output of the shake detection means to stabilize when the power is turned on, and the screen shakes immediately after the power is turned on, making it very difficult to view. This brought about a new problem: it became difficult to use.

0010

SUMMARY OF THE INVENTION It is an object of the present invention to provide an imaging apparatus that solves the above-mentioned problems and can prevent image blur due to instability of the blur detection output.

[0011]

[Features of the Invention] In order to achieve the above object, the present invention has the following features:
A control means is provided to stop the image signal output from the imaging means to the signal processing means until the output of the shake detection means becomes stable, so that the shake detection means starts operating normally and the shake detection output is reduced. The present invention is characterized in that the image signal is input to the image display section only when the image signal becomes appropriate.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on illustrated embodiments.

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

In the figure, reference numeral 1 denotes a variable apex prism (VAP), which is an optical axis decentering means.
Angle Prism). Reference numeral 2 denotes an imaging optical system having an imaging lens 2a including a focusing lens and an aperture 2b.The imaging lens 2a is driven and controlled by a focus drive circuit 3, and the aperture 2b is controlled by an iris drive circuit 4a and an iris control circuit 4b. is driven so that the amount of incident light is controlled. Reference numeral 5 denotes a CCD which is an imaging means for photoelectrically converting a subject image formed on an imaging plane by the imaging optical system 2 into an imaging signal. 6 is C
Gamma correction, blanking processing,
This is a camera process circuit that performs predetermined processing such as adding a synchronization signal, converts it into a standardized standard television signal, and outputs it from the video output terminal, and the television signal output from the circuit 6 is not shown. In addition to being output to the video recorder section, it is also output to the monitor 7 such as an electronic viewfinder.
is supplied to

Reference numeral 8 denotes a blur width detection circuit that detects the blur width of the subject image (width of the edge portion of the subject image) from the video signal output from the CCD 5. The closer to the in-focus state, the smaller the blur width of the subject becomes. Focus detection is performed using this property.

Reference numeral 9 denotes a control circuit composed of, for example, a microcomputer, which controls the entire system.
It consists of a port, A/D converter, ROM, and RAM. This control circuit 9 receives blur width information output from the blur width detection circuit 8 described above and peak value information of high frequency components from a bandpass filter (not shown).
A predetermined drive control signal is output to the focus drive circuit 3 to drive the above-mentioned imaging lens 12a so that the blur width in one field period of the image is minimized and the peak value of the high frequency component is maximized. Further, a detection signal is input to the control circuit 9 from a shake detection sensor 10, which is a shake detection means for detecting the shake amount of the video camera body, which is an imaging device. A correction signal for correcting the optical axis according to the operation mode is output to the VAP drive circuit 11. As a result, V
The AP drive circuit 11 tilts the variable apex prism 1 to decenter the optical axis so that the optical image from the imaging optical system 2 is formed on a predetermined location on the imaging plane of the CCD 5.

FIG. 2 shows details of the variable apex angle prism 1, shake detection sensor 10, and VAP drive circuit 11 described above.

As shown in the figure, the shake detection sensor 10 includes a liquid 1 having a predetermined refractive index in a cylindrical case 12.
3, and a floating body 14 rotatable around a predetermined rotation axis is provided in this liquid 13. This floating body 14 is held in a predetermined position by a closed magnetic circuit composed of permanent magnets 15 provided so as to surround the case 12 when there is no wobbling. Then, the video camera body shakes, and the floating object 1
4 rotates relative to the case 12, the position of the spot light emitted from the light emitting element 16, reflected on the surface of the floating body 14, and incident on the light receiving element 17 for position detection changes. There is. In this way, the position of incidence of light on the light receiving element 17 changes depending on the amount of shake of the video camera body, and the output signal thereof changes. The output signal from the light receiving element 17 is outputted to the above-mentioned control circuit 9 via the position detection circuit 18.

On the other hand, the variable apex angle prism 1 has a liquid 23 having a constant refractive index sealed inside an accordion-shaped container 22 having a bellows sandwiched between two transparent plates 21a and 21b. The structure is as follows. The variable apex angle prism 1 is arranged in front of the imaging optical system 2 and the CCD 5, and is magnetically operated by a VAP drive circuit 11 controlled by a control circuit 9 in accordance with the output of the position detection circuit 18 on the shake detection sensor 10 side. The circuit 24 is driven to tilt the transparent plate 21a of the variable apex angle prism 1 on the object side. transparent plate 2
The amount of tilt of 1a is detected by a detection device consisting of a light emitting element 25 and a light receiving element 26, and its output signal is sent to the position detection circuit 2.
It is output to the control circuit 9 via 7. The control circuit 9 determines that the difference between the output of the position detection circuit 18 on the shake detection sensor 10 side and the output of the position detection circuit 27 on the variable apex prism 1 side is "
0'', the VAP drive circuit 11 is controlled to drive the magnetic circuit 24, and the transparent plate 21a of the variable apex angle prism 1 is tilted.

Next, the operation of the above-mentioned control circuit 9 will be explained according to the flowchart of FIG.

First, when the photographing device is powered on, this routine is started (step 1). As a result, the shake detection sensor 10 is immediately driven (step 2). Subsequently, the timer is reset and time measurement begins (step 3). In this state, only a synchronizing signal is output from the camera process circuit 6, and the video signal from the CCD 5 is cut off (step 4). Next, the value of the timer is checked to determine whether or not a predetermined time period of, for example, 2 to 3 seconds has elapsed during which the output of the shake detection sensor 10 is stabilized (step 5). As a result, if it is determined that the predetermined time has not yet elapsed, the process returns to step 4. If it is determined that the predetermined time has elapsed, the timer is reset and the process moves to the next step (step 6). Then, shake detection sensor 1
Driving of the variable apex angle prism 1 is started in response to the output of 0 (step 7). Next, the video signal from the CCD 5, which had been cut off, is connected and normal recording operation is started (step 8).

Therefore, in this embodiment, after the power is turned on, the camera process circuit 6 does not output a video signal until a predetermined time has elapsed, and the video signal is controlled to be output only after the predetermined time elapses. Therefore, the influence of instability (image shake) due to the rise time of the shake detection sensor 10 can be avoided, and the image shake correction function can be effectively utilized.

[0023] In the above-described embodiment, an example was explained in which the shake correction mechanism was provided integrally with a video camera that is an imaging device.
0. The VAP drive circuit 11 and the control circuit 9 may be configured separately as an adapter that can be detachably attached to the video camera body, or the control circuit 9 may also be configured to be used as the video camera body side.

According to this embodiment, the output of the video signal is stopped from when the power is turned on until the output of the shake detection sensor becomes stable, so that the screen does not appear unnatural immediately after the power is turned on. It is possible to avoid the situation where the image sways and becomes extremely difficult to see. In addition, even though the image stabilization function is activated, it does not work properly immediately after the power is turned on, which may cause confusion such as camera malfunction for beginners. It can be resolved.

[0025]

[Effects of the Invention] As explained above, according to the present invention,
A control means is provided to stop the image signal output from the imaging means to the signal processing means until the output of the shake detection means becomes stable, so that the shake detection means starts operating normally and the shake detection output is reduced. Since the image signal is input to the image display section for the first time when the image signal becomes appropriate, it is possible to prevent image shake due to instability of the shake detection output.

[Brief explanation of the drawing]

FIG. 1 is an electric circuit block diagram of an imaging device showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing in detail the variable apex angle prism, shake detection sensor, and VAP drive circuit 11 of FIG. 1;

FIG. 3 is a flowchart showing the operation of the control circuit shown in FIGS. 1 and 2;

[Explanation of symbols] 1 Variable vertex angle prism 2
Imaging optical system 5 CCD 6 Camera process circuit 7 Monitor 9 Control circuit 10 Shake detection sensor 11 VAP drive circuit

Claims (1)

[Claims] 1. An imaging device that converts an optical image on an imaging plane into an image signal and outputs it, a signal processing device that processes the image signal from the imaging device and outputs it to an image display section, and an imaging device main body. a shake detection means for detecting the amount of shake of the image pickup means; an optical axis decentering means for decentering the optical axis so as to make the optical image coincide with a predetermined position on the image forming surface of the imaging means; and an output from the shake detection means. and a drive control means for driving the optical axis decentering means based on the above, the image signal output from the imaging means to the signal processing means is controlled until the output of the shake detection means becomes stable. An imaging device characterized by being provided with a control means for stopping.