JP3360376B2 - Imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus such as a video camera or a camera section of a camera-integrated VTR.

[0002]

2. Description of the Related Art Conventionally, such an imaging device is used whether it is held by hand or mounted on a tripod.
The determination as to whether the horizontal line of the image projected on the image sensor surface is parallel to the image frame defined by the image sensor has been made by looking through a finder or by looking at a level attached to the image pickup device. Was.

[0003] There has also been a device for automatically maintaining the photographing device horizontal by a weight attached to the tip of a long arm.

[0004]

However, in an image pickup apparatus which does not have a mechanism for automatically maintaining a horizontal position, it takes a skill to operate the image pickup apparatus, and a photographer who is not accustomed to the operation performs the operation. In such a case, there is a problem in that an inclined image is often shot. Even when the operation is performed by a skilled person, the user must always look closely at the viewfinder, which may cause the posture at the time of photographing to be overwhelmed or the image to remain tilted.

Further, when a device for automatically keeping the photographing device horizontal is used, there is a problem that the operation of the photographing device requires considerable physical strength because the device is heavy.

The present invention has been made in order to solve such a problem, and a photographer who is not skilled in operation can always shoot a horizontal image in an image frame even if a photographer uses the photographer. It is an object to provide an imaging device that does not require physical strength for operation.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a tilt detecting means for detecting a tilt of an image sensor around an optical axis, and an image sensor based on an output of the tilt detector. Horizontal maintaining means for maintaining the captured video horizontally with respect to the image frame, wherein the horizontal maintaining means stops the operation when the optical axis stands perpendicular to the horizontal plane. An imaging device. Here, as the tilt detecting means for detecting the tilt of the image sensor around the optical axis, a tilt sensor provided at a position fixed to the image sensor, or a tilt sensor provided at a position fixed to the image sensor is provided. There is a combination of an angular velocity sensor and a circuit for integrating its output. As the horizontal maintaining means for maintaining the image horizontally with respect to the image frame, there is a mechanism for rotating a mechanism for holding the image sensor around the optical axis, or a circuit for electronically converting the projected image into a rotational conversion process. .

[0008]

[0009]

According to the present invention, the optical axis is obtained by integrating the output of an inclination sensor provided at a fixed position with respect to the image sensor or the output of an angular velocity sensor provided at a position fixed with respect to the image sensor. The tilt of the surrounding image sensor is detected, and the mechanism for holding the image sensor is rotated around the optical axis based on the tilt, or the captured image is electronically rotated and converted, so that the captured image is framed. Is kept horizontal with respect to

Further, according to the present invention, when the optical axis stands perpendicular to the horizontal plane, the operation of the means for maintaining the image horizontal with respect to the image frame is stopped.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First embodiment)

FIG. 1 is a block diagram showing the configuration of a first embodiment of the image pickup apparatus of the present invention, FIG. 2 is an explanatory diagram of the operation of the tilt sensor in the image pickup apparatus of FIG. 1, and FIG. FIG. 4 is an explanatory diagram of writing / reading of a memory in the device.

In FIG. 1, an image of a subject is focused on an image sensor surface of an image sensor (not shown) such as a CCD held in an image sensor holder 3 by a lens 2 held in a lens barrel 1. You. Here, the lens barrel 1 and the imaging element holding unit 3 are mechanically fixed. The image of the subject is converted into a video signal by the image sensor and converted into a digital signal by the A / D converter 4, and then one frame is written into the memory 5. Control of writing / reading of the memory 5 is performed by the microcomputer 6
It is performed by

A horizontal tilt sensor 7 is provided on the image pickup element holding section 3.
Has been fixed. Further, a vertical tilt sensor 8 is provided at a predetermined position in the image pickup apparatus, for example, on the image pickup element holding section 3. As shown in FIG. 2, the horizontal tilt sensor 7 detects the tilt θ with respect to the optical axis, and supplies the tilt θ to the microcomputer 6. Further, the vertical tilt sensor 8 detects a tilt ψ with respect to an axis orthogonal to the optical axis on the imaging element surface and supplies the tilt ψ to the microcomputer 6.

The microcomputer 6 controls reading from the memory 5 based on the output of the horizontal tilt sensor 7. That is, if the output of the horizontal tilt sensor 7 is θ, the reading area of the memory 5 is rotated by −θ. As a result, even if the shot image is inclined by θ with respect to the image frame, the image read from the memory 5 is kept horizontal with respect to the image frame.

For example, assuming that the image written in the memory 5 is inside the outer square A in FIG. 3, the image read from the memory 5 is further inscribed in the inscribed circle B of this square and has an aspect ratio of 4: 3. Inside the rectangle C. Therefore, since the size of the image is smaller than the image written in the memory 5, the number of pixels in the horizontal and vertical directions is reduced. When the aspect ratio of the video written in the memory is 4: 3, the number of pixels is further reduced. Therefore, it is necessary to interpolate the pixels read from the memory 5 to make the number of pixels equal to that of the original video. However, if an image sensor having a high resolution and an aspect ratio close to 1 is used, such interpolation processing is not necessary, and a video with a sufficient resolution can be obtained.

Here, when the vertical tilt sensor 8 detects ψ = 90 °, that is, when the image pickup device is pointing directly above or below, the microcomputer 6 stops the reading operation of the memory 5. This is because the horizontal inclination sensor 7 cannot accurately detect the inclination θ when 撮 影 becomes slightly smaller from the state where the photographing device is directly above or below.

The position where the horizontal tilt sensor 7 and the vertical tilt sensor 8 are attached may be anywhere in the image pickup apparatus.

(Second Embodiment) FIG. 4 is a block diagram showing a configuration of an imaging apparatus according to a second embodiment of the present invention. Here, parts corresponding to those in FIG. 1 are given the same numbers. While the first embodiment corrects the tilt by performing a rotation conversion process on the image, this embodiment corrects the tilt by mechanically rotating the image sensor.

In this embodiment, the output of the horizontal tilt sensor 7 provided on the lens barrel 1 is supplied to the first comparator 9 by θ = 0.
And the difference is supplied to the motor driver 11 via the first switching circuit SW1. The motor 12 is driven by a drive signal of the motor driver 11 and rotates the mechanically fixed lens barrel 1 and image pickup element holding unit 3 around the optical axis. As a result, the feedback control is performed so that the output θ of the horizontal tilt sensor 7 becomes 0, so that the image sensor is automatically kept horizontal.

The output ψ of the vertical tilt sensor 8 is compared in the second comparator 10 with a reference value corresponding to ψ = 90 °. Then, when they match, the second comparator 10 outputs the first
A control signal for grounding the switching circuit SW1 is output.

The means for rotating the lens barrel 1 and the image pickup element holding section 3 around the optical axis is provided, for example, by providing a gear on the rotating shaft of the motor 12 and disposing a gear engaged with this gear on the outer periphery of the lens barrel 1. It can be realized by providing. Also, the horizontal tilt sensor 7
The position where the vertical tilt sensor 8 is attached may be any position as long as it is physically fixed to the imaging device.

In this embodiment, there is no possibility that the resolution is reduced unlike the first embodiment. In addition, since the motor 12 rotates the image sensor holding unit 3 together with the lens barrel 1, the load on the motor becomes heavy, but there is an advantage that the back of the flange 12 is less likely to be out of order.

(Third Embodiment) FIG. 5 is a block diagram showing the configuration of a third embodiment of the imaging apparatus according to the present invention. Here, parts corresponding to those in FIG. 1 are given the same numbers. This embodiment is characterized in that an angular velocity sensor is used as means for detecting a horizontal inclination.

The output of the angular velocity sensor 13 is supplied to an integrator 14. The integration circuit 14 integrates the output of the angular velocity sensor 13 and detects the rotation angle of the image sensor. The second switching circuit SW2 added to the integration circuit 14 is a switch for setting a horizontal position serving as a reference for starting integration when the use of the imaging device is started. As a result, the output of the integration circuit 14 becomes a signal indicating the inclination θ from the reference horizontal position.
This signal is compared with a reference value corresponding to θ = 0 in the first comparator 9, and the difference is supplied to the motor driver 11. Then, the motor 12 is rotated by the drive signal of the motor driver 11, and the lens barrel 1 and the imaging element holding unit 3 are rotated around the optical axis, so that the feedback control is performed so that the inclination with respect to the reference horizontal position becomes zero. Can be hung.

Further, in the present embodiment in which the output of the angular velocity sensor is integrated and the inclination is detected, the inclination θ can be accurately detected even when the image pickup device is slightly inclined in the horizontal direction from the state where the image pickup element is directly upward or downward. Therefore, it is not necessary to cut off the feedback control of the motor 12 when the image pickup device is directly above or below. Therefore, in this embodiment, it is not necessary to provide a vertical tilt sensor.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications are possible based on the gist of the present invention, and they are not excluded from the scope of the present invention.

For example, in the first embodiment, it is possible to detect the horizontal tilt by integrating the output of the angular velocity sensor. Further, in the third embodiment, if the output of the angular velocity sensor is supplied to an integrating circuit via a capacitor so as not to integrate the direct current component of the output of the angular velocity sensor, the camera shake in the tilt direction can be suppressed. it can. The same applies to the case where the output of the angular velocity sensor is integrated in the first embodiment.
Further, in the second and third embodiments, the control may be performed by a microcomputer.

[0029]

As described above in detail, according to the present invention, when a photographing device is held by hand without using a tripod and a photographing operation is performed, the level of an image to be photographed is maintained. The labor is remarkably reduced, and even a photographer who is not skilled in shooting can easily shoot a stable image.

Further, since the photographer only needs to pay attention to the photographing range, photographing from a high position or a low position or panoramic photographing, which tend to cause unstable images in the past, can be performed stably.

Furthermore, a stable image can be taken even when the compact and lightweight imaging apparatus is fixed to the photographer's body, for example, the head.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of an operation of a tilt sensor in the imaging device of FIG. 1;

FIG. 3 is an explanatory diagram of writing / reading of a memory in the imaging device of FIG. 1;

FIG. 4 is a block diagram showing a configuration of a second embodiment of the imaging apparatus of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a third embodiment of the imaging apparatus of the present invention.

[Explanation of symbols]

3. Image sensor holding unit, 5. Memory, 6. Microcomputer, 7.
Horizontal tilt sensor, 8: Vertical tilt sensor, 12: Motor,
13: angular velocity sensor, 14: integrating circuit

Continuation of front page (56) References JP-A-5-64063 (JP, A) JP-A-4-331586 (JP, A) JP-A-4-181879 (JP, A) JP-A-3-23781 (JP) JP-A-7-46458 (JP, A) JP-A-5-336422 (JP, A) JP-A-5-252431 (JP, A) JP-A-3-109475 (JP, U) JP-A 3-109474 (JP, U) Japanese Utility Model 3-105074 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/232

Claims (1)

(57) [Claims] 1. A tilt detecting the inclination of the imaging device around the optical axis
Horizontal maintained to keep the horizontal and oblique detection means, the image captured by the imaging device based on an output of said inclination detecting means with respect to the image frame
Means , wherein the horizontal maintaining means has an optical axis standing perpendicular to a horizontal plane.
An imaging device that stops the operation when the operation is stopped.