Television – Camera – system and detail – With electronic viewfinder or display monitor
Reexamination Certificate
1997-12-05
2002-05-21
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
With electronic viewfinder or display monitor
C348S345000, C345S667000
Reexamination Certificate
active
06392701
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image size reducing method of reducing an entered image in the vertical direction, and displaying it in an image display device, and an apparatus using the same method.
As an example of reducing an image size in the vertical direction and displaying said reduced image size in an image display device, a conventional image size reducing method is described below by referring to
FIG. 14
,
FIG. 15
,
FIG. 16
, and FIG.
18
.
To begin with, a first prior art of image size reducing method is described.
An image display device
2
in
FIG. 14
receives a vertical synchronizing signal
21
, a horizontal synchronizing signal
26
, an enable signal
27
, and a clock signal
28
, and displays image data
20
sequentially from the upper left corner to the lower right corner of an image display area. A basic decimating operation is used to recognize the beginning of a horizontal scanning line on the basis of the horizontal synchronizing signal
26
, and to display the image data
20
in the image display area when the enable signal
27
provided by gate circuit
1
is active. That is, as shown in
FIG. 15
, a horizontal synchronizing signal
22
and one or more signals of the entered enable signal
23
and clock signal
24
are gated by the gate circuit
1
, and an enable signal
27
, a clock signal
28
, and a horizontal synchronizing signal
26
are issued, and, as a result, each signal corresponding to image data K of K-th line is decimated by a gate signal
25
.
A specific example of the gate circuit
1
is a gate circuit
3
in FIG.
16
. By such decimating, image data (K+1) is displayed in the image display device
2
in the next horizontal scanning line of displaying image data (K−1) without displaying image data K.
By thus decimating the horizontal synchronizing signal
22
and enable signal
23
at the timing corresponding to an arbitrary horizontal scanning line, the image data
20
corresponding to the decimated horizontal synchronizing signal
26
and decimated enable signal
27
is displayed in the image display device
2
in a decimated state. By varying the decimating rate of the horizontal synchronizing signal
22
and enable signal
23
, the number of lines in the vertical direction of the image data displayed in the image display device
2
can be freely decreased.
Thus, as far as at least the horizontal synchronizing signal
22
and one or both of the enable signal
23
and clock signal
24
are decimated, even if the image data
20
is not decimated, the image data in that portion is not displayed in the display device, and therefore, for example, certain LCD, PDP and corresponding display device can be used as the image display device to be used herein.
By making use of this method, hitherto, horizontal synchronizing signal
22
and one signal or both of the enable signal
23
and clock signal
24
are decimated in fixed horizontal scanning lines in each frame, and the entered image was reduced and displayed in the image display device
2
.
In a second prior art, horizontal scanning lines to be decimated are selected arbitrarily in the horizontal scanning lines for composing the image and only the image data other than said selected horizontal scanning lines is written into the memory. The image reduced by a number of the decimated horizontal scanning lines is stored in the memory and the reduced image size can be displayed in the image display device by sequentially reading out the image data.
After writing image data of all horizontal scanning lines for composing the image into the memory, a reduced image size can be displayed in the image display device by reading out sequentially only the image data other than the horizontal scanning lines arbitrarily selected for decimating, similarly.
In the conventional method, however, the line numbers of the selected horizontal lines on the basis of the vertical synchronizing signals are fixed in all frames. That is, image size reduction was realized by decimating horizontal scanning lines always at the same positions in every frame.
In a third prior art, there is a method using a digital filter, and said image size reducing method in the vertical direction by using two-tap digital filter showing in
FIG. 17
is described below. Herein, a delay circuit
4
in
FIG. 17
is a delay element for delaying the entered image data by time of one horizontal scanning line.
In
FIG. 18
, line s, line (s+1), line (s+2), and line (s+3) are horizontal scanning lines for composing an original image before reduction, and pixels
29
a
,
29
b
,
29
c
,
29
d
are pixels belonging to individual horizontal scanning lines. The image data expressing the pixel value of each pixel is expressed by a, b, c and d individually.
The digital filter in
FIG. 17
calculates pixel data a and pixel data b using formula 1, and produces pixel data e of pixel
29
e
of a newly created line r.
e=a×p1+b×q1 (where p1 and q1 are integers) [1]
By operating this calculation on image data of all pixels of line s and line (s+1), image data of all pixels for composing line r is created newly. Herein, by replacing lines s and (s+1) by line r, the number of lines can be decreased. Similarly, from the horizontal scanning lines of line (s+2) and line (s+3), image data f of pixel
29
f
of horizontal scanning lines of line (r+1) can be newly created using formula 2.
f=c×p2+d×q2 (where p2 and q2 are integers) [2]
Herein, the number of lines can be decreased by the same process as process in the above operation.
Similarly, by operation of formula 1, formula 2 sequentially, the vertical size of the image can be reduced.
Herein, p1, p2, . . . , q1, q2, . . . are integers determined by the reduction rate.
By determining the number of operations by the reduction rate in the vertical direction, the original image can be reduced to a desired size.
The conventional image size reducing methods are described so far, but when the original image size is reduced in the vertical direction by employing the first method and second method, since the horizontal scanning lines to be decimated are always fixed in each frame, the image data of the decimated horizontal scanning lines is completely unseen in the image display device. For example, if the horizontal synchronizing signal corresponding to the image of the horizontal line of which width is equivalent to the width of one horizontal scanning line is decimated, the horizontal line is completely eliminated. Moreover, a fine character may be considerably deformed and is very hard to be seen.
In the third method, the multiplier and line memory are needed, and the circuit is large and complicated. And, if the number of taps of digital filter is small, deterioration of frequency characteristic is significant, the edge in the vertical direction is vague, and it causes a problem of deterioration of image quality when a still image such as a personal computer image is reduced.
The invention is intended to solve such problems, and it is hence an object thereof to present an apparatus for realizing reduction of image size in the vertical direction and the image size reducing method, suppressing loss of horizontal line, deformation of fine character, distortion of image in the vertical direction, and vague edge in the vertical direction, in a simple circuit.
SUMMARY OF THE INVENTION
The image size reducing method of the invention comprises a counter for counting horizontal synchronizing signals of entered image signals, a gate signal generating circuit for generating a gate signal using the count value of the counter, the reduction rate in the vertical direction of the image, the vertical synchronizing signal and horizontal synchronizing signal, and a gate circuit for decimating horizontal synchronizing signal H at least one of enable signal E and clock signal C by using the gate signal, and an entered signal is displayed in an image display devic
Akeyama Tamotsu
Amano Yoshinori
Garber Wendy R.
Matsushita Electric - Industrial Co., Ltd.
Ratner & Prestia P.C.
Tillery Rashawn N.
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