JP3200276B2 - 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 imaging apparatus using a two-dimensional solid-state imaging device such as a CCD as an imaging device.

[0002]

2. Description of the Related Art In recent years, with the progress of two-dimensional solid-state imaging devices, it has become possible to increase the number of pixels, reduce the price, and reduce the size.
TV standards such as NTSC have been able to provide sufficient image quality. In a video camera and the like, a camera shake correction process is performed to obtain a high-quality moving image.

[0003] Camera shake means that when a person takes a picture with a video camera, his or her hand or body moves irrespective of his / her own intention, and the shot image moves up, down, left, or right. This is a phenomenon that gives an unpleasant sensation when viewing the video on a television monitor or the like.

[0004] In a conventional video camera, for example, a variable apex prism called a VAP is used to avoid such a camera shake phenomenon.

FIG. 5 shows a configuration example of a conventional image pickup apparatus with a camera shake correction function.

In FIG. 5, reference numeral 1 denotes a horizontal angular velocity sensor which detects an angular velocity based on a horizontal movement of an image pickup apparatus due to a camera shake or the like. The detection signal of the angular velocity sensor 1 is subjected to arithmetic processing by the control circuit 2 so as to correct the horizontal movement of the imaging device, differentiated, and the acceleration component is detected and supplied to the actuator 3. The actuator 3 drives the glass plate 4a of the prism 4 in the horizontal direction. The prism 4 is formed by joining two glass plates 4a and 4b with a bellows-shaped spring member 4c and enclosing an optically transparent liquid 4d in a space surrounded by the two glass plates and the spring member. is there. The axis 4e provided on the glass plate 4a of the prism 4
Is connected to an actuator 3 for horizontal driving, and a shaft 4f provided on the glass plate 4b is connected to an actuator 8 for vertical driving. Therefore, the glass plate 4
a is rotated in the horizontal direction, and the glass plate 4b is rotated in the vertical direction. The prism 4 is called a variable apex angle prism (VAP), which is described in detail in Japanese Patent Laid-Open No. 12518/1990, and is not described here.

The rotation angle of the glass plate 4a, which is rotatable in the horizontal direction by the actuator 3, is detected by the apex angle sensor 5, and is processed by the control circuit 2 to be processed.
Supplied to

Reference numeral 6 denotes a vertical angular velocity sensor which detects an angular velocity based on a vertical movement of the image pickup device due to a camera shake or the like. The detection signal of the angular velocity sensor 6 is differentiated in the control circuit 7, the acceleration is detected, the arithmetic processing is performed so as to correct the vertical movement of the imaging device, and the calculated signal is supplied to the actuator 8. The actuator 8 drives the glass plate 4b of the prism 4 in the vertical direction. Actuator 8
The rotation angle of the glass plate 4 b that can be rotated in the vertical direction is detected by the apex angle sensor 9, processed by the control circuit 7, and supplied to the actuator 8.

[0009] That is, the horizontal,
The vertical angular velocity is detected, and based on this, the variable vertical angle prism is moved horizontally and vertically by the actuator,
Camera shake and the like are corrected by refracting light and controlling the subject image not to move on the imaging surface of the solid-state imaging device.

Reference numeral 10 denotes a photographing optical system which forms a subject image on an image sensor. Reference numeral 11 denotes an image sensor, and a two-dimensional solid-state image sensor is used in current video cameras and the like. The output of the image sensor 11 is output to a recording device or a television monitor via a signal processing circuit (not shown).

[0011]

However, with the number of pixels of a two-dimensional solid-state imaging device used in a conventional video camera or the like, it is necessary to obtain a resolution required for a large-screen image, a hard copy, a computer graphics, and the like. Not enough. The number of pixels of a two-dimensional solid-state imaging device is usually about 400,000 pixels, and the number of pixels is limited to 2 million pixels even for high definition, and further improvement is considered difficult.

[0012]

According to the present invention, a light receiving surface of a solid-state imaging device having two-dimensionally arranged pixels and a subject image formed on the light receiving surface by an imaging optical system are relatively displaced. A first imaging mode having displacement means for causing the image to be corrected for camera shake by the displacement,
A second imaging mode for obtaining a high-resolution image by synthesizing a signal of a plurality of images obtained by relatively moving the position of the imaging device and the subject image formed by the displacement unit by a relatively small amount is selectively performed. A switching means is provided.

According to one embodiment of the present invention, when a photographer is required to select a first or second imaging mode arbitrarily or automatically, a camera shake is required. By moving the image sensor position relative to the subject image formed by the optical system relatively to compensate for blur due to blurring, etc., moving image information free of camera shake can be obtained, and high resolution can be obtained. If required, the position of the image sensor and the subject image formed by the optical system are relatively slightly moved, and the output signals of a plurality of screens of the image sensor are synthesized to obtain high-resolution image information. The imaging device can be provided. Further, according to the embodiment of the present invention, since the synthesizing operation is performed in accordance with the output of the motion detection circuit, it is possible to provide an imaging device capable of obtaining optimal high-resolution image information.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a basic configuration of an image pickup apparatus according to the present invention. In FIG. 1, FIG.
The same components as those described above are denoted by the same reference numerals, and description thereof will be omitted. Reference numeral 101 denotes a controller for increasing the number of pixels. In the solid-state imaging device 11, the light receiving portions of each pixel are arranged in two directions of X and Y, and the interval is larger than the light receiving portion of one pixel. The high pixel resolution controller 101 displaces the relative position between the subject image formed by the optical system 10 and the image pickup device, and apparently the light receiving portions of the pixels of the solid-state image pickup device 11 do not generate light between the light receiving portions. A control signal for changing the position of the variable apex angle prism 4 so as to fill the sensitivity region is transmitted to the control circuit 2 and the control circuit 7.
And the variable apex angle prism 4 is driven by the actuators 3 and 8 based on the control signal.

When using the imaging apparatus of the present embodiment,
First, the photographer determines the operation mode. 102 and 1
Reference numeral 03 denotes a mode switch for that purpose. Connected to a in the case of the first imaging mode for obtaining a relatively low-resolution image, and connected to b in the case of the second imaging mode for obtaining a relatively high-resolution image. Therefore, in the first imaging mode, the variable apex angle prism 4 is controlled based on the angular velocity information (acceleration information) in the horizontal direction and the vertical direction, and is controlled so as to correct blur such as camera shake, and the second imaging mode is performed. In the case of the mode, increase the apparent number of pixels, that is, apparently,
The light receiving unit is controlled so as to fill a light insensitive region between the light receiving units.

The signal from the solid-state image pickup device 11 is digitized by an A / D converter 104 and
6a, 106b, 106c, and 106d. In the case of the first imaging mode, the scan conversion circuit 105 does not function, and always writes a digitized image signal into, for example, the memory 106a and outputs it as it is via the frame memory data selector 107. In the case of the second imaging mode, the digital image signal output in accordance with the method described in detail below is divided and stored in the frame memories 106a, 106b, 106c, and 106d. A high-resolution image is output by alternately reading out 106a, 106b, 106c, and 106d. The output signal of which the number of pixels is increased by the scan conversion circuit 105 is output to the recording device 109, the monitor printer 111, the display 110, and the like via the signal processing circuit 108.

Next, a second imaging mode for obtaining a high-resolution image will be described. FIG. 2 is a plan view showing the relative movement of the light receiving unit of the solid-state imaging device 11 and the subject image in a time series in the imaging device of the present invention. The figure shows a case where the object image side is fixed. In FIG. 2A, a light receiving unit is controlled by a variable apex angle prism 4 driven by an actuator on the basis of a control signal of a high pixel controller 101, for example, in the order of 1, 2, 3, and 4 for each frame of a solid-state imaging device. Go to If the respective frames are referred to as first to fourth frames, the frame period of the image to be synthesized is the first to fourth frames.
It is represented by the sum of the fourth frame period.

Therefore, the solid-state imaging device 11 is divided into first to fourth
The accumulation, transfer, and reading are performed within each frame period, and the frame memories 106a, 106b, and 106 shown in FIG.
When the images are sequentially stored in c and 106d for display, recording, or printing, the images are combined as shown in FIG. Therefore, the resolution is doubled in both the X and Y directions. Here, the object image side has been described as fixed, but the object image side is actually displaced by refraction by the variable apex angle prism.

By having a combination of the two operation modes, the photographer can select and record, display, or print a high-resolution image and an image without blur. In addition, in the case of the second imaging mode, a moving image can be output by repeating this operation, or a high-resolution still image may be obtained by controlling the displacement means for one cycle.

Another embodiment will be described below.

FIG. 3 is a block diagram showing a second embodiment of the present invention. 3, the same components as those in FIG. 5 shown in the conventional example are denoted by the same reference numerals, and description thereof will be omitted.
Reference numeral 301 denotes a motion detection circuit that detects the motion of the subject from the output of the image sensor.

As a method of motion detection, a method of comparing a plurality of images photographed at different times (fields) in units of minute blocks and detecting a motion vector of a subject is known, for example, from JP-A-1-98563. This may be used.

In the second embodiment of the present invention, when photographing a subject, the photographing apparatus first enters the first photographing mode. When the motion detection circuit 301 determines that the subject is moving, the imaging device directly performs recording, display, and the like in the first imaging mode. If it is determined that the subject is stationary, the mode switch is connected to b, and the mode of the photographing apparatus is automatically switched to the second high-resolution imaging mode.

As described above, by automatically switching the first and second image pickup modes of the image pickup apparatus according to the amount of movement of the subject, optimum image pickup can always be performed.

In the present embodiment, in the second high-resolution imaging mode, the number of pixels is increased at the same magnification in both the X and Y directions, but it is needless to say that different magnifications are possible.
For example, the image and the image sensor may be shifted only in the X direction. Further, in this embodiment, apparently, the light receiving section of each pixel is displaced so as to fill the light insensitive area between the light receiving sections, and the output of the position during the displacement of each light receiving area is output as one pixel. By displaying or recording, equivalently, X,
Although the resolution in the Y2 direction is improved, it is also possible to increase the number of pixels by moving the light receiving units so that they seem to overlap each other due to displacement.

FIG. 4A shows a solid-state image pickup device 1 of an image pickup apparatus in which the light receiving portions are apparently moved so as to overlap each other.
It is a top view which shows the apparent movement of one light receiving part in time series. In this case, if the overlap of the light receiving sections is の of that of the light receiving sections, the MTF is reduced, so that the generation of aliasing distortion generated by the solid-state imaging device is suppressed. An optical low-pass filter to be configured becomes unnecessary.

In the image pickup apparatus of this embodiment, a variable apex angle prism is used to temporally change the relative positional relationship between the image of the incident optical system and the pixels of the two-dimensional solid-state image sensor. A method in which a polarizer whose direction of polarization can be controlled is provided in an optical path as disclosed in Japanese Patent Publication No. 57-31701, or an angle in an optical path as disclosed in Japanese Patent Application Laid-Open No. 60-223388. Japanese Patent Application Laid-Open No. 59-13476 discloses a method in which an optical member that changes the traveling direction of an incident light beam by changing the angle thereof is provided, for example, a glass plate having a uniform thickness capable of transmitting light is provided and its angle is controlled to perform displacement. In Japanese Patent Application Laid-Open No. 3-201883, a method for displacing the entire image pickup apparatus, or a method for changing a part or the whole of the image pickup optical system. A method of obtaining an image by temporally changing the relative positional relationship between the image of the incident optical system and the pixels of the two-dimensional solid-state image sensor, and oscillating the image sensor in a plane perpendicular to the optical axis by a piezo element or the like. Any method may be used, such as a method of causing it.

Further, in the above embodiment, the relative change between the optical image and the image pickup means is not changed in the second image pickup mode in response to the detection of the shake. The control signal may be superimposed on the control signal for high-resolution displacement for each field. By doing so, a high-resolution image signal without blur can be obtained in the second imaging mode.

Further, in the embodiment, an example in which the pixel pitch is shifted by 1/2 pixel pitch in the horizontal and / or vertical directions has been described, but it goes without saying that the shift may be an integer fraction of the pixel pitch.

[0031]

As described above, according to any one of the first to fourth aspects of the present invention, a photographer can arbitrarily or automatically select an image recording mode so that there is no blurring such as camera shake. An imaging device capable of selectively obtaining a low-resolution image and a high-resolution image can be provided.

Moreover, since these two types of images are obtained using a common displacement means, there is no need to use separate displacement means for obtaining each image, and the configuration is extremely simple. Also,
According to the invention described in claim 4 or 5, since the synthesizing operation is performed according to the output of the motion detection circuit, optimal high-resolution image information can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an element array and an image in a second imaging mode of the first embodiment, and a pixel array of a high-resolution image after synthesis.

FIG. 3 is a diagram of a second embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between an element array and an image in a second imaging mode of a second embodiment, and a pixel array of a high-resolution image after synthesis.

FIG. 5 is a diagram showing a conventional configuration example.

Claims (5)

(57) [Claims] A solid-state imaging device; a photographing optical system for forming a subject image on the solid-state imaging device; a light-receiving surface of the solid-state imaging device; and a subject image formed on the light-receiving surface by the imaging optical system. Means for relatively displacing the image, a first imaging mode for obtaining a low-resolution image in which camera shake has been corrected by the displacement means, a subject image to be formed by the displacement means, and a position of an image sensor. A second imaging mode for obtaining a high-resolution image by synthesizing signals of a plurality of images obtained by relatively moving the image by a relatively small amount, and a control means capable of selectively switching the two modes. An imaging apparatus characterized by having: 2. The imaging apparatus according to claim 1, further comprising: a shake detecting unit, wherein the displacement unit is controlled in accordance with an output of the shake detecting unit in the first imaging mode. 3. An image pickup apparatus according to claim 1, further comprising a memory for synthesizing a time-series output signal obtained in said second image pickup mode to form an output image and equivalently increasing the number of pixels. . And means for detecting a motion vector of the subject, wherein the first and second motion vectors are detected based on motion vector information of the subject.
The imaging apparatus according to claim 1, wherein the imaging mode is switched. 5. A mode switching unit for detecting a motion vector of a subject, wherein the mode switching unit switches to the second imaging mode when the detecting unit determines that the subject is stationary. The imaging device according to claim 1, comprising: