JPH0832865A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain an image pickup device with simple mechanism in which a tracking speed of automatic focusing is fast by allowing a solid-state image pickup element to follow an image forming position of an object image moving in response to a change in the position of the object. CONSTITUTION:The image pickup device is provided with an image pickup lens system 1, a solid-state image pickup element 3 arranged to the image forming position of an object image to receive an object image and a moving means 5 to move the solid- state image pickup element 3 along an optical axis. A control means 4 controls the moving means 5 so that the solid-state image pickup element 3 follows an image forming position of an object image moved in response to the movement of the object. Furthermore, a correction means (rocking correction circuit) 6 corrects the rocking of a received image attended with the movement of the solid-state image pickup element 3. For example the fog of an object image is detected to move properly the solid-state image pickup element 3 based on the result to make the image received position in matching with the image forming position of the object image. Furthermore, the motion vector of the rocking of the image pattern is detected and the pattern of a desired position among the received patterns is selected based on the rocking quantity and the pattern is magnified and corrected into a prescribed size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device, for example, an image pickup device used for a video camera, a TV camera or the like.

[0002]

2. Description of the Related Art When an image is picked up by an image pickup device, the image forming position of a subject image moves according to the variation of the position of the subject. Since the position of the solid-state image sensor is fixed in the conventional image pickup apparatus, it is necessary to keep the image formation position of the subject image constant by appropriately driving the lens according to the variation of the position of the subject.

Generally, as a method for driving a lens, there is a totally extended focusing method for driving the entire photographing lens, and an inner focus method or a rear focus method for driving only a part of the correction lens group of the photographing lens. .

[0004]

In the case of the fully-extended focusing method, the entire lens group constituting the taking lens is driven along the optical axis. Therefore, the weight of the correction lens group to be driven is large and large. As a result, the load on the drive mechanism becomes large, and the structure of the mechanism becomes complicated and large.

Further, since the weight of the correction lens group to be driven is large, rapid focusing with high responsiveness cannot be performed, and so-called autofocus becomes difficult. Further, a large motor is required to drive the correction lens group having a large weight. Therefore, in the case of a video camera that places importance on portability, there is a disadvantage that the increase in power consumption for driving a large motor becomes fatal.

On the other hand, in the case of the focusing method in which only the lens group forming a part of the photographing lens is driven, the weight of the correction lens group to be driven is smaller than in the case of the whole extension type focusing method. Therefore, the disadvantages of the auto-focus following speed and power consumption described above are improved to some extent.

However, in the inner focus method or the rear focus method, since only a part of the lens group of the taking lens is driven, a so-called movable lens group that moves during focusing (focusing) and a so-called fixed lens group that does not move are mixed. To do. For this reason, since two lens barrels are required, there is a disadvantage in that the drive mechanism is likely to be complicated as compared with the case of the whole extension type focusing method.

Further, since a part of the lens group of the taking lens is moved, in order to minimize the variation of chromatic aberration,
It is also necessary to achromatize the correction lens group for focusing. As a result, the correction lens group cannot be configured with one lens component, and is forced to be configured with two or more lens components. Thus, although the weight of the correction lens group is small from the viewpoint of the entire taking lens, the weight of the correction lens group has not been sufficiently reduced, so that the structure of the drive mechanism is still complicated and large.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image pickup apparatus which is mechanically simple and has a high autofocus following speed.

[0010]

In order to solve the above-mentioned problems, in the present invention, a photographing lens system and a solid for arranging at a position where a subject image is formed by the photographing lens system for receiving the subject image. An image pickup device, a moving means for moving the solid-state image pickup device along an optical axis, and the moving means so that the solid-state image pickup device follows an image forming position of a subject image that moves according to the movement of the subject. There is provided an image pickup apparatus comprising: a control unit for controlling the image pickup device and a correction unit for correcting the shake of the image receiving screen due to the movement of the solid-state image pickup device.

According to a preferred aspect of the present invention, the correcting means includes a shake amount detecting means for detecting a shake amount of the image receiving screen based on an output from the solid-state image sensor, and the shake amount detecting means. And a shake amount correction means for correcting the shake of the image receiving screen based on the detected shake amount.

[0012]

In general, in the image pickup apparatus, the image forming position of the subject image also moves according to the change of the object position, but the optical system is provided between the moving amount of the subject position and the moving amount of the image forming position of the subject image. There is a certain correlation peculiar to. As described above, in the image pickup apparatus of the present invention, the control unit appropriately controls the moving unit of the solid-state image pickup element to cause the solid-state image pickup element to follow the imaging position of the subject image that moves according to the change of the subject position. You can

Specifically, for example, blurring of the subject image (depending on a change in the subject position) is detected, and based on the detection result, the moving means appropriately moves the solid-state image pickup device so that the image receiving position is the subject. Correction is performed so as to match the image formation position.

The image pickup apparatus of the present invention further comprises a correction means including a shake amount detecting means for detecting the shake amount of the image receiving screen and a shake amount correcting means for correcting the shake of the image receiving screen based on the shake amount. , Screen vibration due to movement of the solid-state image sensor is corrected. Specifically, the shake motion vector of the image receiving screen is detected, the screen at the desired position is selected from the image receiving screen based on the detected amount of shake, and the selected screen is enlarged and corrected to a screen of a predetermined size.

As described above, in the image pickup apparatus of the present invention, since the motion vector of the image is detected and the shake is corrected, the screen vibration caused by the movement of the solid-state image pickup element is eliminated. In addition, camera shake stabilization may be performed by utilizing this shake correction mechanism. The control by the control means may be control by a finder and a human, or may be control by an autofocus (AF) system. The driving by the moving means may be manual driving or motor driving.

[0016]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically illustrating a configuration of an image pickup apparatus according to an embodiment of the present invention, and FIGS. 1A and 1B are diagrams corresponding to an infinity photographing state and a short distance photographing state, respectively. Is. The image pickup apparatus of FIG. 1 includes a taking lens 1 including a plurality of lens components positioned in order from the subject side. A low-pass filter 2 is provided behind the taking lens 1, that is, on the side opposite to the subject with respect to the taking lens 1. The low-pass filter 2 is a known filter and has a function of cutting infrared rays.

A solid-state image pickup device 3 such as an area sensor is provided at a position behind the low-pass filter 2 and at a position where a subject image is formed. Solid-state image sensor 3
Is composed of an image receiving unit for receiving a subject image and a storage unit for storing the received image information. Solid-state image sensor 3
The output of is connected to the inputs of the control unit 4 and the shake correction circuit 6 described later. The illustrated apparatus also includes solid-state image sensor moving means 5 for moving the solid-state image sensor 3 along the optical axis.

When the image forming position of the subject image moves with the change of the subject position, so-called blur of the subject image is detected in the solid-state image sensor 3. The blur amount of the subject image depends on the change in the subject position. Information about the blur of the subject image detected by the solid-state image sensor 3 is input to the control unit 4. The control unit 4 calculates the image formation position of the subject image, that is, the position to which the image receiving unit of the solid-state image pickup device 3 should move, based on the blur information of the subject image. The control unit 4 outputs the calculated position information to the solid-state image sensor moving means 5. The solid-state image sensor moving means 5 moves the solid-state image sensor 3 to the image forming position of the subject image based on the position information from the control unit 4. A series of operations from the detection of the blur amount of the subject image due to the change of the subject position to the movement of the solid-state image sensor 3 are performed in real time.

As described above, in this embodiment, the solid-state image pickup device 3 can be made to follow the image forming position of the subject image which moves with the change of the subject position. As described above, in the present embodiment, since the light and small solid-state image pickup device is moved, not only the load on the driving unit is very small, but also quick focusing, that is, focusing with a high following speed is possible.

FIG. 2 is a schematic diagram showing the configuration of the shake correction circuit 6 of FIG. The shake correction circuit 6 shown in the figure corrects the shake (vibration) of the image receiving screen caused by the shake (vibration) of the solid-state imaging device 3 with respect to the optical axis. The shake correction circuit 6 includes an A / D converter 11 for receiving an analog signal output from the solid-state image sensor 3 and converting the analog signal into a digital signal. The output of the A / D converter 11 is the frame memory 1
2 and the input of the motion vector detection circuit 13. The motion vector detection circuit 13 receives the output of the A / D converter 11 and detects the motion vector of the shake of the image receiving screen.

On the other hand, the frame memory 12 receives the output of the A / D converter 11 and stores the image receiving screen, and based on the amount of screen shake detected by the motion vector detecting circuit 13, a desired image receiving screen is stored. Select the position screen and output. That is, the read position of the frame memory 13 is controlled based on the screen shake information detected by the motion vector detection circuit 13. The output of the frame memory 13 is connected to the input of the enlargement correction circuit 14. The enlargement correction circuit 14 enlarges and corrects the image selected and output by the frame memory 13 to an original screen of a predetermined size and outputs the image. The output of the expansion correction circuit 14 is further output to the D / A converter 1.
5 inputs. The D / A converter 15 can convert a digital signal into an analog signal and provide an output signal without screen vibration.

In this embodiment, the image formation position of the subject image is obtained by detecting the blur of the subject image. However, the change of the subject position is detected directly or indirectly through an appropriate means. It is obvious that the imaging position of the subject image may be obtained by performing

[0023]

As described above, according to the present invention, it is possible to perform focusing by moving the light and small solid state image pickup device by providing the image pickup position tracking mechanism of the solid state image pickup device. Therefore, it is possible to realize an image pickup apparatus that is mechanically simple and has a high autofocus following speed.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating a configuration of an image pickup apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a shake correction circuit of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photographic lens 2 Low-pass filter 3 Solid-state image sensor 4 Control part 5 Solid-state image sensor moving means 6 Shake correction circuit 11 A / D converter 12 Frame memory 13 Motion vector detection circuit 14 Enlargement correction circuit 15 D / A converter

Claims (3)

[Claims] 1. A photographing lens system, a solid-state image pickup device arranged at an image forming position of a subject image by the photographing lens system to receive the subject image, and for moving the solid-state image pickup device along an optical axis. Moving means, control means for controlling the moving means so that the solid-state imaging device follows the image formation position of a subject image that moves in accordance with the movement of the subject, and with the movement of the solid-state imaging device. An image pickup apparatus comprising: a correction unit for correcting shake of an image receiving screen. 2. The shake correction means for detecting the shake quantity of the image receiving screen based on the output from the solid-state image sensor, and the shake quantity detected by the shake quantity detection means. 2. The apparatus according to claim 1, further comprising a shake amount correcting means for correcting shake of the image receiving screen. 3. The apparatus according to claim 1, wherein the solid-state image sensor is an area sensor.