JPH04196878A - Automatic swing device for video camera - Google Patents

Abstract

PURPOSE:To automatically incline a photographing element or a lens by providing a swing mechanism so that a high frequency component signal may be maximum and a feed back circuit to adjust the swing mechanism. CONSTITUTION:A swing mechanism is controlled and a back-end lens group 1-4 is turned based on the output signal of a reference signal generating source 9 within a control circuit 8. Then, the polarity and the amplitude of a reference frequency component signal synchronous-detected from a video signal are detected with an original reference frequency signal. That is, shifting correction is equivalent to making the amplitude maximum and the swing correction can be attained automatically by adjusting and feeding back the direction of the rotation and the quantity of a rotational angle of the back-end lens group 1-4. Thus, a system used as the detecting mechanism of an inclined quantity, that is, the rotational angle for the swing correction and as a swing correcting mechanism by an automatic swing device can be realized.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a tilting device for a video camera, an electronic still camera, etc., and in particular detects a high frequency component (focal voltage) from a video signal, and detects a high frequency component (focal voltage) from a video signal, The present invention relates to an automatic tilting device suitable for a TTL video system that controls the tilt of a lens or an image pickup device so that the following is achieved.

[Conventional technology]

As a camera that can focus on multiple subjects, there is a system in which a tilt mechanism is built into the interchangeable lens of a 35 mm reflex camera. For large cameras,
There are many products that tilt the lens and tilt the film. All of these tilt mechanisms are based on manual operation and require the skill of the photographer.

Furthermore, there is an autofocus (AF) camera that measures distances at multiple points in order to bring a plurality of objects into almost an in-focus state without using a tilt mechanism. For example,
A camera that emits light to multiple targets as described in Japanese Patent Publication No. 62-20522, a camera that adopts the closest distance AF data as described in Japanese Patent Application Laid-Open No. 59-107332, and a camera that uses AF data for the closest distance as described in Japanese Patent Publication No. 1987-107332, There is a camera that adjusts the focus so that multiple subjects are within the depth of field. These cameras reduce the possibility of failure in focus by selecting one of the AF data of multiple subjects or by averaging them, and actively focus on subjects with two or more points. It is not meant to focus on. Therefore, these problems are as follows.

Conventional cameras with a tilt mechanism require the photographer to manually tilt the lens while looking through the viewfinder, which is cumbersome. If the lens or the like is tilted, the focus will shift, and the lens must be moved further for focusing, which may lead to a missed photo opportunity. Further, since the tilt mechanism must be moved one time while confirming its effect in the viewfinder, it was impossible to employ the tilt mechanism in a viewfinder camera.

As a solution to this problem, Japanese Patent Application Laid-Open No. 2-7980
There is a camera with a built-in tilting mechanism that can automatically tilt the film surface or lens to bring objects at different distances into focus, as described in Japanese Patent No. 8.

[Problem to be solved by the invention]

This conventional camera with a built-in tilting mechanism that can automatically tilt the film surface or lens needs to be equipped with a multi-point distance measurement sensor that can measure distances from at least three points on the subject. There were problems in that the structure was complicated and the weight was heavy.

Furthermore, when tilt correction is simply performed in a conventional camera with an automatic tilt mechanism, the size of the subject image is reduced and enlarged. For example, in a camera with a built-in tilting mechanism that tilts the film surface, the size of the subject image increases in the portion where the film surface moves away from the subject, and the size of the subject image decreases in the portion where the film surface approaches the subject. In other words, this is not a problem with a still camera that captures still images, but in the case of a video camera that captures moving images, the size of the subject image changes before and after tilting, which becomes a major problem.

This invention was made to deal with the above-mentioned circumstances,
The image sensor or lens can be automatically tilted to focus on multiple subjects at different distances, and the size of the subject image on the image sensor corresponds to the amount of tilt at that time. An object of the present invention is to provide a video camera with a built-in automatic tilting device that can convert the reduced iJr and enlarged signals into video signals.

[Means to solve the problem]

The above-mentioned lens has a tilting mechanism, and the tilting correction of the imaging that makes one movement so that the high frequency component of the imaging signal is maximized is not performed by rotating part or all of the lens or the imaging element. The motor 1 is operated so as to rotate this with small rotational fluctuations at a predetermined period, and further, the subject image on the image pickup device is rotated according to the amount of tilting.
This is achieved by using the reduced and enlarged data as the video signal.

[Effect]

The principle of operation of the present invention will be explained based on FIGS. 3 and 4.

First, Scheimpfluf's law will be explained.

Generally, if the photographic lens system (1) and the image sensor (2) are parallel, then the subject (18) is oblique. The entire area of the subject (18) is out of focus. In order to focus on the entire area, the intersection point Q of the object plane of the image sensor (2) should intersect with the extension line of the inclination of the photographic lens system (1). This is called Scheimpfluf's law, and when the image sensor (2) is tilted as shown in Figure 4, and when the photographing lens system (2) is tilted as shown in Figure 3.
1) may be tilted.

In this way, even if the subject (18) is tilted, by rotating and tilting part or all of the photographic lens system (1) or the image sensor (2), the subject (18) can be photographed at an angle.
It becomes possible to focus on the entire area. In this way, in the case of a still camera that captures still images, skew correction is achieved.

However, in a video camera that records moving images, for example, the image sensor (
In the case as shown in FIG. 6, in which 2) is rotated and tilted by an angle θ, the size of the subject image changes due to the tilt correction. In other words, the size of the subject image increases from ○A to ○C when the image sensor (2) moves away from the photographic lens system (1), and conversely, when the image sensor (2) moves away from the photographic lens system (1), the size of the subject image increases from ○A to ○C. In the closer area, the size of the subject image decreases from OB to OD. Therefore, the size of the subject image changes, or fluctuates, due to the tilt correction, resulting in a screen that is difficult to view in a moving image.

As a countermeasure against this, the tilt correction amount, for example, the image sensor (
Image sensor (2) including point A based on the rotation angle θ of 2)
By multiplying the subject image on the side by ○A/○C and simultaneously multiplying the subject image on the image sensor (2) side including point B by 0B10D, it is possible to prevent variations in the size of the subject image.

〔Example〕

Hereinafter, an embodiment of this video camera with a built-in tilting mechanism will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. In FIG. 1, 1 is a photographic lens system, 1-1 is a front lens group, 1-2 is a device lens group that converts the axial light beam converged by the front lens group (1-1) into a substantially parallel light beam; 1-3 is an aperture, 1-4 is a rear lens group used as a rotating lens in this example,
2 is a fixed image sensor in this example, and 3 is an image sensor (2)
a preamplifier circuit (4) for amplifying the video signal obtained by the preamplifier circuit (3), a video magnification calculation circuit (5) for reducing and enlarging the video signal amplified by the preamplifier circuit (3) in accordance with the amount of tilting by the tilting mechanism; 6 is a camera circuit that generates a camera signal based on the video signal corrected by the tilt mechanism and the video scaling calculation circuit (4), and 6 is a camera circuit that generates a high frequency frequency from the video signal processed by the video scaling calculation circuit (4). This is a high frequency component extraction circuit that extracts the components. 7 is an output signal change component of the high-frequency component extraction circuit (6), that is, a change due to minute rotation of the rear lens group (1-4) used as a rotating lens that is a part of the photographic lens system (1). This is a detection circuit that detects a slightly fluctuating reference frequency component. 9 is used to slightly change the rear lens group (1-4) used as a rotating lens, and detect the rotation direction and amount of rotation of the rear lens group (1-4) for tilt correction. This is a reference signal generation source that generates the original reference frequency component signal. Reference numeral 11 denotes a synchronous detection circuit that synchronously detects the detection signal obtained from the detection circuit (7) using the original reference frequency component signal generated by the reference signal generation source (9). 10 controls the tilt mechanism based on the polarity and amplitude of the reference frequency component signal detected by the synchronous detection circuit (11), that is, performs tilt correction so that the amplitude of the high frequency component of the image sensor (2) is maximized. This is a control signal generation circuit that generates control signals for. 8 is a control circuit composed of a reference signal generation source (9), a control signal generation circuit (10), and a synchronous detection circuit (11). 13 is a stainless steel motor, ultrasonic motor, etc. that rotates and controls the tilting mechanism.
This is a motor that is driven by pulse signals. 12, the motor (1) is controlled by the output signal of the control signal generation circuit (10).
3) is a tilt drive circuit that activates. Furthermore, the control signal generated by the control signal generation circuit (10) is also input to the video scaling calculation circuit (4) during operation, and is used for scaling calculation processing of the video signal, which will be described later.

14 is a motor gear that is attached to the motor (13) and rotates together with the motor; 15 is a transmission gear that transmits the rotation of the gear (14); and 16 is a rear lens group (1- 4) is attached and the rear lens group (1-
4) is a rotating lens frame that rotates together with the lens frame. Further, the rotating lens frame (16) is provided with a rotating gear (17) for transmitting the rotation of the transmission gear (15).

In the above explanation, each component and its function were explained,
Next, the overall operation including the tilting mechanism and circuits such as the control circuit (8) will be explained.

When the subject is oblique to the video camera, the image plane of the subject and the image plane of the image sensor (2) do not overlap, that is, they shift diagonally, and the high frequency components of the video signal at this time are small. You can see that the image is out of focus.

Therefore, the tilting mechanism is controlled based on the output signal of the reference signal generation source (9) in the control circuit (8).

Rotate the rear lens group (1-4). At this time.

The polarity and amplitude of the reference frequency component signal which is synchronously detected from the video signal is detected using the original half frequency signal. In other words, tilt correction is equivalent to maximizing this amplitude, and by adjusting and feeding back the direction of rotation and the amount of rotation angle of the rear lens group (1-4) using the control circuit (8), The tilt correction is automatically achieved.

Next, a second embodiment will be described using FIG. 2.

In FIG. 2, the same reference numerals as in FIG. 1 have the same functions and functions as in FIG. The difference from the embodiment in Fig. 1 is that in Fig. 1, the tilt correction function is
), but in the embodiment shown in Fig. 2, the image sensor (2) has a tilt correction function, and the motor (13) is attached to the image sensor (1-4). (2) It is movable so as to perform tilt correction by rotating it while slightly rotating it. In this case, the rear lens group (1-
4) is fixed.

According to the embodiment shown in FIG. 2, the feedback circuit system connects the image sensor (
2), preamplifier circuit (3), video magnification calculation circuit (4),
A high-frequency component extraction circuit (6), a detection circuit (7) for a slightly fluctuating reference frequency component, and a control circuit (8).

It is composed of a tilt drive circuit (12), a motor (13), a gear that transmits the rotation of the motor, and an image sensor moving means. In other words, since the retrace circuit system is configured separately from the photographic lens system (1), there is no need for any moving parts in the photographic lens system (1) other than the zooming mechanism, and there is less influence on lens design, making it even simpler. An automatic tilting device can be realized.

Above is the first part. In the embodiment shown in FIG.
Since the photographing lens system (1) or the image sensor (2) rotated by the motor (13) is small and light, the type of motor (13) is not particularly limited, but a pulse drive motor such as a stepping motor or an ultrasonic motor may be used. If used, the inertia of the rotor will be small and fine rotation can be controlled appropriately, which is preferable. Furthermore, since such a motor is of a non-contact type and has a long life, or the speed of the motor is easy to control, it is possible to make an excellent automatic fanning device.

Next, unlike a still image camera or the like, a moving image video camera or the like has a problem in that the size of the image changes during tilt correction, as explained in the section on operation. Basically, to solve this problem, it is sufficient to correct the image size according to the amount of rotation for tilt correction.

The image size correction method used in the rotation method of the image sensor (2) of the second embodiment will be described below with reference to FIGS. 5 and 6.

Fig. 5 shows how the image sensor (2) is connected to the optical axis (
19), it has a structure in which it can be rotated in the left-right direction (horizontal direction).

A motor gear (14) that rotates together with the motor (13) is attached to the motor (13). The rotation of this motor gear (14) is transmitted to the image sensor (2) by a rotating gear (17) attached to the image sensor (2). With the above configuration, by rotating the motor (13), the image sensor (2) is moved along the optical axis (
19), it can be rotated in the left and right directions.

Next, using FIG. 6, the image of the subject (18) on the image sensor (2) when the image sensor (2) rotates with respect to the optical axis (19) of the photographic lens system (1). The change in image size will be explained.

Point P is the Yaro pupil position of the photographic lens system (1), and point ○ is the intersection of the image sensor (2) and the optical axis (19) of the photographic lens system (1), as well as the center of rotation of the image sensor (2). , points A and B are two points on the left and right on the image sensor (2) when the image sensor (2) is perpendicular to the optical axis (19) of the photographic lens system (1), respectively. Point C is the intersection of the straight line including points P and A and the surface including the image sensor (2) when the image sensor (2) is rotated by an angle θ around point O. This is the intersection of the straight line containing the image sensor (2) and the plane containing the image sensor (2) when the image sensor (2) is rotated by an angle θ around the point O.

That is, when the image sensor (2) is not rotating (when θ is O), the size of the image of the subject (18) on the image sensor (2) is the line segment AO and the line segment BO. . On the other hand, when the image sensor (2) is rotated by an angle θ, the image sensor (
2) The size of the image of the subject (18), which is the same as in the case where θ is O, is the line segment CO and the line segment D○. That is,
On the side of point A, the size of the image of the subject (18) increases by the ratio of the length of the line segment (Co/AO), and on the side of point B, the size of the image of the subject (18) increases by the ratio of the length of the line segment (Co/AO).
8) The size of the image is the ratio of the length of the line segment (D).

/BO) will be smaller. The way in which the size of the image of the subject (18) changes corresponds to the rotation angle θ of the image sensor (2), so it is sufficient to perform correction in accordance with the rotation angle θ.

Next, a method of correcting the size of the image of the subject (18) according to the rotation angle θ will be described.

According to the similarity relationship between the triangle PAO and the triangle including point C, s)l ri)'+1JCsirl Therefore, the formula for OC can be summarized as follows. Similarly, according to the similarity relationship of the triangle of point PB○, the formula for OD can be summarized as follows. Also,
In these two equations, the sign of sin θ is different depending on whether it is positive or negative, but if θ is made positive and negative on the side away from and approaching the photographic lens system (1), equations (1) and (2) are the same. It takes shape.

The meaning of this expression will be explained below. When the image sensor (2) is not rotating (when θ is O), the amplified video signal at the position of point A is used as it is as the input signal of the camera. When the image sensor (2) is rotated by the angle θ, the amplified video signal at the position of point C on the image sensor (2) determined by the above formula is used instead of the original video signal at point A. , used as an input signal for the camera. In this case, the image of the subject (18) on the image sensor (2) on the side toward the point is
The video signal directly obtained in step 2) is reduced, and conversely, the image of the object 18) on the image sensor (2) on the side of point B is the enlarged video signal directly obtained by the image sensor (2). .

From another perspective, this means changing the reading range of the video signal on the image sensor (2) in response to the tilt correction.

From the above, the final subject (1
8) The size of the image does not change before and after the tilt correction, and automatic tilting is achieved with a video camera that is a moving image.

〔Effect of the invention〕

According to the present invention, there is no need to install a special rotation angle detection mechanism for tilting in addition to the tilting correction mechanism by the automatic tilting device, and the rotation angle for tilting can be slightly varied in practice, and at the same time, automatically. It can have a tilting function. In other words, in the conventional camera with a built-in tilt mechanism, at least three of the objects are
There was a need for a multi-point distance measuring means that could measure more than just one point.

However, according to the present invention, it is possible to realize a system that serves both as a rotation angle detection mechanism for correcting tilt amount, that is, tilt correction, and as a tilt correction mechanism using an automatic tilt device. As a result, it is possible to easily configure a tilt correction mechanism using an automatic tilt device.

In addition, fluctuations in the size of the subject's image due to tilt correction, which was not a problem with still image cameras, are automatically corrected according to the rotation angle, which is effective even with video cameras that shoot moving images. It is possible to realize an automatic tilting device.

[Brief explanation of the drawing]

Fig. 1 is a system configuration diagram showing a first embodiment of the present invention, Fig. 2 is a system configuration diagram showing a second embodiment of the invention, and Fig. 3 is a system configuration diagram showing a second embodiment of the present invention.
Figure 4 and Figure 4 are diagrams explaining Scheinpul's law, Figure 5
The figure is a block diagram of a tilting mechanism that rotates the image sensor with respect to the optical axis of the photographic lens system, and FIG. 6 is a model diagram showing the variation in the number of subject images when tilting is corrected. 1...Photographing lens system, 2...Image sensor, 3...
Preamplifier circuit, 4... Image magnification calculation circuit. Death...Camera circuit, 6...High frequency component extraction circuit, 7
...Detection circuit for slight fluctuation reference frequency component, 8. Control circuit, 9. Reference signal generation source, 10. Control signal generation circuit, 11. Synchronous detection circuit, 12. Tilt shame circuit, 13・
- Motor, 14... Motor gear, 18... Subject, 19... Optical axis.

Claims (1)

[Claims] 1. An automatic tilting device using a TTL video system that extracts a high frequency component signal from a video signal obtained from an image sensor (2), comprising: a tilting mechanism and a tilting mechanism so that the high frequency component signal is maximized; , An automatic tilting device for a video camera, characterized in that it is provided with a feedback circuit for adjusting the tilting mechanism. 2. The tilting mechanism rotates all or part of the photographic lens system (1) while changing the angle slightly at a predetermined reference frequency, and detects the reference frequency minute angle fluctuation component signal from the high frequency component. The video camera according to claim 1, wherein the tilting mechanism is driven by a motor so as to detect the polarity and amplitude of the detection signal and correct the tilting of the image plane with respect to the image sensor (2). Automatic fanning device. 3. The tilting mechanism rotates the image sensor (2) while changing the angle slightly at a predetermined reference frequency, detects the reference frequency minute angle fluctuation component signal from the high frequency component, and detects the polarity of the detection signal. The image sensor (
2. The automatic video camera tilting device according to claim 1, wherein the tilting mechanism is driven by a motor so as to correct the tilting of the video camera. 4. The angle of the tilting mechanism is controlled by a motor driven by a pulse signal, such as a stepping motor or an ultrasonic motor.
The automatic tilting device for a video camera according to any of paragraph 4. 5. The video signal obtained from the image sensor (2) is subjected to arithmetic processing for reduction and enlargement according to the angle-controlled tilting amount, and the video signal subjected to the arithmetic processing is used as an input to the camera circuit. Claims 1 to 3
An automatic tilting device for a video camera according to any of paragraphs.