Television – Image signal processing circuitry specific to television – Hue control
Reexamination Certificate
2001-01-04
2003-09-30
Miller, John (Department: 2614)
Television
Image signal processing circuitry specific to television
Hue control
C348S653000, C348S587000, C348S592000, C348S654000, C358S520000
Reexamination Certificate
active
06628342
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a video signal processing apparatus which adjusts a hue of an image displayed on a display device when a video signal outputted by a video signal reception means is displayed on the display device.
BACKGROUND OF THE INVENTION
In recent years, in a television image receiver, when a video signal is processed by using the digital signal processing technology, it has been increasing to adjust the hue of a display screen by using a memory, a ROM, and the like, and a circuit configuration has been increasing with this increase. So, in order to minimize the circuit configuration and to rationalize a circuit configuration, it has been desired for a video signal processing apparatus which shares circuits such as the ROM as much as possible and therefore is rationalized, and such a video signal processing apparatus has been developed.
A conventional video signal processing apparatus will be briefly described with reference to figures.
FIG. 8
is a block diagram illustrating the conventional video signal processing apparatus X. As shown in
FIG. 8
, the video signal processing apparatus X is provided with an address value output means
510
which outputs an address value for adjusting the hue; multipliers
501
,
502
,
503
, and
504
; adders
505
and
506
; a cos &Dgr;&thgr; data ROM
507
which records the cos &Dgr;&thgr; data shown in FIG.
7
(
b
) (hereinafter, referred as “ROMcos &Dgr;&thgr;”); and a sin &Dgr;&thgr; data ROM
508
which records the sin &Dgr;&thgr; data shown in FIG.
7
(
a
) (hereinafter, referred as “ROMsin &Dgr;&thgr;”). Further, a hue adjustment means Y which adjusts the hue of the video signal received by a video signal reception means
511
to output to the display device
512
is composed of multipliers
501
,
502
,
503
, and
504
, and adders
505
and
506
. Further, the address value which is outputted by the address value output means
510
can be freely set by a user.
The hue adjustment in the video signal processing apparatus X so constructed will be described with reference to figures.
A video signal contains two color difference signals, that is, a B-Y signal and an R-Y signal. Then, though the hue is decided by these two signals, this is shown by a coordinate where a B-Y signal and a R-Y signal are regarded on an axis of abscissa and on an axis of ordinate, respectively, as shown in FIG.
2
. In
FIG. 2
, &thgr; shows the original states of the inputted color difference signals, and the coordinate of the signal which is composed of the R-Y signal and the B-Y signal which are the inputted color difference signals. Further, how much the user changes the hue from this original state, that is, the amount of the change corresponds to &Dgr;&thgr;. (Here, it is also expressed as “to twist a hue” that the user changes the hue). Then, as shown in
FIG. 2
, the hue is, for example, shown such as a point A and a point B. Incidentally, it is &thgr;=0 in the case of blue, the coordinate of which becomes (A, 0), and it is &thgr;=90 in the case of red, the coordinate of which becomes (0, A). Hereinafter, the coordinate of the A point (starting point) and the coordinate of the B point (correction point) are represented as ({R-Y}a,{B-Y}a) and ({R-Y}b,{B-Y}b), respectively. The following relational expressions stand between these coordinates:
{
R
-
Y}b={R
-
Y}a
×cos &Dgr;&thgr;+{
B
-
Y}a
×sin &Dgr;&thgr; (1)
{
B
-
Y}b={B
-
Y}a
×cos &Dgr;&thgr;−{
R
-
Y}a
×sin &Dgr;&thgr; (2)
Therefore, for example in
FIG. 2
, it can be said that the video signal processing apparatus X should perform the operation of moving the hue shown by the A point to the B point. Further, the calculations of the above-described formulae (1) and (2) are performed in the hue adjustment means Y. Hereinafter, the operation of the video signal processing apparatus X will be described.
While the address value S
501
outputted by the address value output means
510
is set by user, this address value S
501
is inputted to ROMcos &Dgr;&thgr;
507
and ROMsin &Dgr;&thgr;
508
, respectively. In the ROMcos &Dgr;&thgr;
507
, data corresponding to the inputted address value S
501
is decided by cos &Dgr;&thgr; data shown in FIG.
7
(
b
) to be outputted as an output signal S
504
. Similarly in ROMsin &Dgr;&thgr;
508
, data corresponding to the inputted address value S
501
is decided by sin &Dgr;&thgr; data shown in FIG.
7
(
a
) to be outputted as an output signal S
505
. These data are inputted to the hue adjustment means Y, that is, multipliers
501
,
502
,
503
, and
504
, and adders
505
and
506
. Then, the calculations of the above-described formulae (1) and (2) are performed in this hue adjustment means Y, and the processed data is outputted as a modified R-Y signal S
506
and a modified B-Y signal S
507
, in addition to the R-Y signal S
502
and the B-Y signal S
503
which are inputted to the hue adjustment means Y.
For example, in case where the inputted address value is (00) in a hexadecimal number notation (hereinafter, the same notation is employed), when this is inputted to ROMcos &Dgr;&thgr;
507
and ROMsin &Dgr;&thgr;
508
as the address signal S
501
, the output signal S
505
(=sin &Dgr;&thgr;) becomes “0”, and the output signal S
504
(=cos &Dgr;&thgr;) becomes “1” according to FIGS.
7
(
a
) and
7
(
b
). When these are inputted to the above-described formulae (1) and (2), it results as follows:
{
R
-
Y}b={R
-
Y}a×
1
+{B
-
Y}a×
0
={R
-
Y}a
(3)
{
B
-
Y}b={B
-
Y}a×
1
−{R
-
Y}a×
0
={B
-
Y}a
(4)
Therefore, the inputted signals are outputted as they are. In other words, the coordinate of the B point is equal to that of the A point, meaning that the A point is equal to the B point. This means that a correction point does not exist and that there is no change in the hue.
Next, a description will be given of a case where the phase is rotated by 90 degrees. In case where the inputted address value is (40), this is inputted to ROMcos &Dgr;&thgr;
507
and ROMsin &Dgr;&thgr;
508
as the address signal S
501
, whereby the output signal S
505
becomes “1” and the output signal S
504
becomes “0”, respectively, according to FIGS.
7
(
a
) and
7
(
b
). When these are inputted to the above-described formulae (1) and (2), it results as follows:
{
R
-
Y}b={R
-
Y}a×
0
+{b
-
Y}a×
1
={B
-
Y}a
(5)
{
B
-
Y}b={B
-
Y}a×
0
−{R
-
Y}a×
1
={R
-
Y}a
(6)
Therefore, it is understood that the phase has rotated by 90 degrees from the A point.
However, the video signal processing apparatus X as described above results in that the whole circuit size becomes large because two kinds of ROMs, the cos &Dgr;&thgr; data ROM and the sin &Dgr;&thgr; data ROM, are required in view of its configuration.
SUMMARY OF THE INVENTION
The present invention is directed to solve the above problems, and it is an object of the present invention to provide a video signal processing apparatus which can reduce a circuit size in comparison with the conventional video signal processing apparatus as well as exhibit the performance which is equivalent to the conventional video signal processing apparatus.
To accomplish the above-described object, according to a first aspect of the present invention, a video signal processing apparatus which adjusts a hue of an image displayed on a display device when a video signal outputted from a video signal reception means is displayed on the display device comprises: address value output means which outputs an address value for adjusting the hue; addition means for generating a second address value corresponding to a
Miller John
Wenderoth , Lind & Ponack, L.L.P.
Yenke Brian
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