Television – Camera – system and detail – Camera image stabilization
Reexamination Certificate
1997-08-12
2002-10-29
Vu, Ngoc-Yen (Department: 2612)
Television
Camera, system and detail
Camera image stabilization
C348S219100, C348S220100, C348S240200, C348S296000, C396S055000
Reexamination Certificate
active
06473120
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image processing apparatus for applying a predetermined signal processing to the image taken in the form of electrical signals, and an image pickup apparatus utilizing such image processing apparatus, and more particularly an image processing apparatus having a function of enlarging a taken image, and an image pickup apparatus employing such the image processing apparatus.
2. Related Background Art
With the recent development of the digital image processing technology for digitizing and processing the electrical image information obtained with an image pickup device, the function called “electronic zooming” or “electronic teleconverter” is widely adopted in the video cameras or the like for the consumer use.
As an example,
FIG. 1
shows a video camera
700
provided with the electronic teleconverter function.
In this video camera
700
, the electronic teleconverter function is turned on and off by shifting an electronic teleconverter switch
710
to a terminal A or B.
At first there will be explained the operation of the video camera
700
, which is performed when the electronic teleconverter function is turned off by placing the electronic teleconverter switch
710
at the terminal A.
In this state, a switch
706
is switched to a terminal A under the control of a control circuit
714
.
The image of an unrepresented object is transmitted through unrepresented plural optical lenses, a zoom lens
701
provided coaxially therewith and an optical low-pass filter
702
, and is focused on the image-pickup surface of a CCD (charge-coupled device)
703
, thereby being converted (hereinafter called photoelectric conversion) into an electrical image signal.
The image signal obtained in the CCD
703
is supplied, through an amplifier circuit
704
, to an analog/digital (A/D) converter
705
.
The A/D converter
705
digitizes the image signal, supplied through the amplifier circuit
704
, into digital image data, which are supplied to a terminal A of the switch
706
.
Since the switch
706
is shifted to the terminal A in this state, as explained above, the image data obtained in the A/D converter
705
are supplied from the switch
706
to a camera signal processing circuit
707
.
The camera signal processing circuit
707
applies a predetermined signal processing to the image data from the switch
706
, and supplies an encoder
708
with thus processed image data.
The encoder
708
applies a modulation according to a predetermined television format to the image data supplied from the camera signal processing circuit
707
, and supplies a digital/analog (D/A) converter
709
with thus modulated image data.
The D/A converter
709
converts the image data from the encoder
708
into an analog television signal (image signal) for output from an output terminal Iout.
FIG. 2
shows the arrangement of image taking pixels (hereinafter simply called pixels) on the image-pickup surface of the CCD
703
, a distance
800
x
of the sampling points in the X-direction and a distance
800
y
of the sampling points in the Y-direction.
As shown in
FIG. 2
, the sampling point for a given pixel
703
n
is defined in the X- and Y-directions by
800
xn
and
800
yn
(indicated by arrows) and can be regarded as a single point for each pixel.
Since such arrangement of the pixels in the X- and Y-directions determines the upper limit of the spatial frequency of the image that can be picked up, the frequency characteristics of the above-mentioned optical low-pass filter
503
are determined according to the range of the spatial frequency of the picked-up image mentioned above.
Consequently the video camera
700
is provided with the optical low-pass filter
503
coaxially with the unrepresented plural optical lenses and is so designed as to cut off, by such optical low-pass filter
503
, the high spatial frequencies which generate fold-back noises at the photoelectric conversion by the CCD
703
.
Also the video camera
700
realizes the image enlarging function solely by the focal length determined by the zoom lens
701
.
More specifically, the image angle of the analog television signal released by the D/A converter
709
is same as the image angle (hereinafter also called image size) of the image focused on the image-pickup surface of the CCD
703
.
When an image magnification rate is designated by the manipulation of a zoom switch
712
, the control circuit
714
supplies a driver
715
with a drive command based on the manipulation of the zoom switch
712
.
The driver
715
drives an actuator
716
based on the drive command from the control circuit
714
.
According to the driving of the actuator
716
, the zoom lens
701
displaces parallel to the optical axis.
In this manner the above-mentioned focal length is determined, whereby obtained is an image of the magnification rate designated by the manipulation of the zoom switch
712
.
In the following there will be explained the operation of the video camera
700
, which is performed when the electronic teleconverter function is turned on by placing the electronic teleconverter switch
710
at the terminal B.
As in the above-explained case where the electronic teleconverter function is turned off, the image of an unrepresented object is transmitted through unrepresented plural optical lenses, the zoom lens
701
, the optical low-pass filter
702
, the CCD
703
, the amplifier circuit
704
and the A/D converter
705
thereby being converted into image data, which are supplied to the terminal A of the switch
706
.
The image data released from the A/D converter
705
are also supplied to an electronic teleconverter extracting circuit
715
.
The electronic teleconverter extracting circuit
715
applies an image extracting process, to be explained later, to the image data from the A/D converter
705
, and supplies the terminal B of the switch
706
with the image data subjected to such extracting process.
If the shutter is turned off in this state by shifting a shutter switch
711
to a terminal A, the switch
706
is also switched to the terminal A under the control of the control circuit
714
.
Consequently the image data released from the A/D converter
705
are supplied to the camera signal processing circuit
707
through the switch
706
.
In this case, the image data of an image size equal to that of the image focused on the image-pickup surface of the CCD
703
are supplied to the camera signal processing circuit
707
, and are output from the output terminal Iout through the encoder
708
and the D/A converter
709
.
On the other hand, if the shutter is turned on by switching the shutter switch
711
to the terminal B, the switch
706
is also switched to the terminal B under the control of the control circuit
714
.
Consequently the extracted image data output from the electronic teleconverter extracting circuit
715
are supplied to the camera signal processing circuit
707
.
Thus, in this case, while the shutter is turned on, the extracted image data obtained in the electronic teleconverter extracting circuit
715
are supplied to the camera signal processing circuit
707
, and are output from the output terminal Iout through the encoder
708
and the D/A converter
709
.
In the following there will be explained the extracting process of the above-mentioned electronic teleconverter extracting circuit
715
.
As an example, in case the CCD
703
picks up image
901
d
within a frame
901
shown in
FIG. 3A
, the image data based on such image
901
d
are supplied to the electronic teleconverter extracting circuit
715
.
The electronic teleconverter extracting circuit
715
extracts, from the supplied image data (image
901
d
), image data (image
902
d
) within a frame
902
of an area corresponding to ¼ of that of the frame
901
and enlarges thus extracted image data twice vertically and horizontally to obtain enlarged image data (image
902
d
′) as shown in FIG.
3
B.
Consequently, when the electronic teleconverter function is turned on and the s
Hirasawa Masahide
Takahashi Koji
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