Television – Display or receiver with built-in test signal generator,...
Reexamination Certificate
1999-04-09
2001-09-18
Eisenzopf, Reinhard J. (Department: 2614)
Television
Display or receiver with built-in test signal generator,...
C348S177000, C348S178000, C348S180000, C348S461000, C348S476000, C348S184000
Reexamination Certificate
active
06292216
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a control signal generating circuit suitable for use with a display apparatus or the like in which a picture screen, for example, is divided into a plurality of areas and images of different picture qualities are displayed in these areas. More particularly, the present invention relates to a control signal generating circuit in which, when a picture quality of every area is improved by using a marker signal, the marker signal can be made inconspicuous.
2. Description of the Related Art
In a display apparatus such as a television receiver for displaying a video signal based on a television broadcasting and a video signal played back from a video tape or the like, for example, in order to improve a display picture quality of a still picture represented by a photographic picture or the like and a moving picture represented by a motion picture or the like, there have heretofore been implemented picture quality improvement techniques such as enlarging a brightness difference (hereinafter referred to as a contrast ratio) between a white level and a black level of displayed picture by increasing an amplifying ratio of a video signal, for example, or emphasizing a contour of a picture (hereafter referred to as a sharpness).
There have been realized a variety of semiconductor integrated circuits (hereinafter referred to as ICs) having more than one such picture quality improvement function to improve these picture quality improvement functions by control means using a direct current voltage (hereinafter referred to as a DC voltage) from the outside, for example, or information transmission means such as a so-called bus communication and so on. As representing examples of such semiconductor integrated circuit, there are known a preamplifier IC for use in a video amplifying circuit, for example, an RGB decode IC for decoding luminance/color difference signals to provide red/green/blue signals or the like.
By the way, in a monitor display apparatus for displaying an output of a computer, for example, it has been a main purpose to display information of characters, digital numbers and so on of document and spreadsheet or the like outputted from a computer. Therefore, the monitor display apparatus is generally used in order to display an image signal supplied from a computer in the form of a binary signal of “1/0”, for example, at a proper luminance level.
On the other hand, in a computer having multimedia capabilities, not only information of the above-mentioned characters and digital number but also images of photographs, and moving pictures and the like from a disk apparatus and a video card had heretofore been displayed in an arbitrary range called a window. In that case, since the images of photographs, moving pictures and so on thus taken into the computer are low in contrast and sharpness as compared with information such as characters, digital numbers and the like, when they are displayed together with such information, picture qualities of photograph and moving picture or the like are deteriorated considerably.
Therefore, in such monitor display apparatus, in order to improve picture qualities of images of photograph and moving picture or the like, it has been considered to improve the above-mentioned contrast ratio and sharpness.
However, in the conventional monitor display apparatus, it is unavoidable that such picture quality improvement such as enlargement of the above-mentioned luminance difference, the contour emphasis and so on is uniformly effected on the whole of the picture screen. As a result, when the picture screen has therein the display areas of characters and digital numbers or the like, there is then the risk that these displayed characters and digital numbers or the like become difficult to read. In particular, when displayed characters and digital numbers or the like are too high in brightness, user's eyes tire easily.
Also, recently, as so-called internet have been developed and a text broadcasting is widespread, increasing an opportunity at which general television receivers display images of photograph and moving pictures or the like and characters and digital numbers or the like on one picture screen. Accordingly, also in such a television receiver, when such picture quality improvement such as enlargement of the above-mentioned luminance difference and the contour emphasis or the like is uniformly effected on the whole of the picture screen, there is then the risk that these characters and digital numbers displayed on the picture screen become difficult to read.
On the other hand, the inventors of this application have previously proposed a display apparatus (PCT application No. JP98/04747) in which a marker signal comprised of combinations of arbitrary patterns of primary colors of predetermined levels is formed in a video signal, this marker signal is detected and different image processing is effected at every detected area.
That is, as shown in
FIG. 9
, red/green/blue video signals (R/G/B) inputted to input terminals
1
R,
1
G,
1
B are respectively supplied through capacitors
2
R,
2
G,
2
B to a preamplifier IC
3
. In this preamplifier IC
3
, the supplied video signals (R/G/B) are respectively supplied through clamping circuits
31
R,
31
G,
31
B to sharpness improvement circuits
32
R,
32
G,
32
B, which will be described later on, and further outputted through amplifiers
33
R,
33
G,
33
B which will be described later on.
The video signals (R/G/B) outputted from this preamplifier IC
3
are amplified by an output amplifier
4
and then outputted through capacitors
5
R,
5
G,
5
B. Further, these video signals (R/G/B) thus outputted are DC-voltage-converted by a cutoff adjustment amplifier
6
and then supplied to a cathode-ray tube (hereinafter referred to as a CRT)
7
, for example, serving as a display means, thereby resulting in an image based on picture-quality-improved video signals (R/G/B), which will be described later on, being displayed on the screen of the CRT
7
.
A microcomputer (hereinafter referred to as a microcomputer: although not shown) exiting within this apparatus and which controls a variety of functions is adapted to generate data of first and second DC voltages for controlling the above-mentioned sharpness and data of first and second DC voltages for controlling the contrast ratio, for example. Further, the data thus generated are supplied to D/A-converting (hereinafter referred to as a DAC) circuits
34
A and
34
B; and
35
A and
35
B, in which they are respectively converted into control DC voltages.
The control DC voltages thus converted by these DAC circuits
34
A and
34
B; and
35
A and
35
B are selected by switch circuits
36
,
37
and then supplied to the above-mentioned preamplifier IC
3
. Thus, the preamplifier IC
3
controls the above-mentioned sharpness improvement circuits
32
R,
32
G,
32
B and the above-mentioned amplifiers
33
R,
33
G,
33
B in accordance with the supplied control DC voltages, thereby resulting in the sharpness and the contrast ratio being improved.
Further, in this apparatus, video signals (R/G/B) upon which marker signals for designating arbitrary areas of the picture screen from, for example, an outside computer (not shown) are superimposed are supplied to the input terminals
1
R,
1
G,
1
B. Here, the marker signals are comprised of arbitrary signal patterns, respectively, and signal patterns
101
a
,
101
b
,
102
a
,
102
b
comprising these arbitrary marker signals are respectively provided at four corners of an area
100
to be detected as shown in
FIG. 10
, for example.
Accordingly, in the apparatus shown in
FIG. 9
, the video signals from the above-mentioned input terminals
1
R,
1
G are supplied through amplifiers
8
R,
8
G to input terminals of shift registers
9
R,
9
G, and the video signal from the input terminal
1
B is supplied through a comparator
8
B to clock terminals of the shift registers
9
R,
9
G. The signals thus accumulated in these shift registers
9
R,
Shimizu Katsuhiro
Umemura Shunji
Eisenzopf Reinhard J.
Maioli Jay H.
Natnael Paulos M.
Sony Corporation
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