JPH05137153A - Outline correcting device - Google Patents

Abstract

PURPOSE:To improve color bleeding generated in a boundary part of a color due to a fact that an edge of a color signal becomes dull, and to provide the outline correcting circuit at a low cost by a simple constitution. CONSTITUTION:The device is prodded with a color demodulating circuit 12 for demodulating a color signal to a color difference signal, emphasizing signal adding circuits 25, 26 for adding an emphasizing signal to a sudden change part of the color difference signal, and a color modulating circuit 19 for modulating the color difference signal to which the emphasizing signal is added, to the original color signal. In such a way, color bleeding in a boundary part of the color signal is eliminated, and virtual resolution of a color is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contour correction device for improving the sharpness and definition of color signals in color television receivers, video tape recorders and the like.

[0002]

2. Description of the Related Art FIG.
An example of the conventional contour correction device disclosed in No. 6 is shown. In the figure, the color signal input from the input terminal 1 is
The first delay circuit 2 delays by a predetermined time D, and the second delay circuit 3 further delays by a predetermined time D. As a result, the three color input signals a, b, and c of the switching switch 9 are simultaneously input with the color signal at the current time and the color signals at time D and time 2D before.

Now, the output signal of the first delay circuit 2 is f
If (t), the current color signal is represented by f (t + D), and the output signal of the second delay circuit 3 is represented by f (tD). FIG. 6 shows the positional relationship of these three signals. The subtractor 4 calculates [amplitude of signal f (t)]-[amplitude of signal f (t + D)] (hereinafter,
It is abbreviated as "f (t) -f (t + D)". ) Is calculated every time,
The absolute value circuit 6 outputs the absolute value A of the subtraction result. Similarly, the subtractor 5 calculates f (t) -f (tD) every time, and the absolute value circuit 7 outputs the absolute value B of the subtraction result. Comparator 8
Compares the absolute values A and B, and during the period of A <B, switches the switching switch 9 to the terminal a and outputs the signal f (t + D).
Is output, and when A = B, the signal is switched to the terminal b and the signal f
(t) is output, and in the period of A> B, the signal is switched to the terminal c and the signal f (tD) is output.

As a result, the signal g (t) shown by the thick solid line in FIG. 6 is output from the output terminal 10. This output signal g (t)
The waveform of is a signal in which the color signal (t) with a slow rise time is corrected to a signal waveform with a fast rise time, which makes the rise time short and the rise time of the same signal in the rise period of the color signal. In the down period, on the contrary, the fall time becomes short.

[0005]

In the conventional contour correcting apparatus, the subtracters 4 and 5 are used to generate f (t) -f (t + D) and f (t).
(t) -f (tD) is calculated every time, absolute values circuits 6 and 7 compare respective absolute values A and B of the subtraction result with a comparator 8, and in the period of A <B, the switching switch 9 To the terminal a to output the signal f (t + D), when A = B, to the terminal b to output the signal f (t), and when A> B, switch to the terminal c. Since a switching operation of outputting the signal f (tD) is required, it is extremely difficult to improve the sharpness and definition of the color signal, and the complicated configuration is expensive.

The present invention has been made in order to solve the above problems. Even when the signal edge is blunted in the signal processing and color fringing occurs at the color boundary, the rise of the waveform of the color signal, It is an object of the present invention to provide a low-pitch contour correction device with a simple structure and a sharp fall.

[0007]

According to a first aspect of the present invention, an emphasizing signal adding circuit is a first-order differentiating circuit for first-order differentiating a color difference signal, and a second-order differentiating circuit for further differentiating the first-order differentiating signal. And a subtractor for subtracting a signal secondarily differentiated from the original color difference signal, and an emphasis signal level variable circuit for changing the amplitude level of the emphasis signal. Also,
According to a second aspect of the present invention, the emphasis signal adding circuit is provided with first and second delay circuits for delaying the color difference signal by a predetermined time, and before being delayed from the signal delayed by the first delay circuit. A first subtractor for subtracting a signal, a second subtractor for subtracting a signal delayed by a second delay circuit from a signal delayed by the first delay circuit, and outputs from the first and second subtractors An adder for adding the signals to be added, an adder for adding the output signal of the adder to the output signal of the first delay circuit, and an emphasis signal level variable circuit for changing the amplitude level of the emphasis signal. It is characterized by

[0008]

In the contour correcting apparatus according to the present invention, the emphasis signal is added to the abrupt change portion of the color difference signal by the emphasis signal adding circuit, the rising and falling edges of the waveform are sharpened, and the original color signal is modulated. .. When adding the emphasis signal, it is not necessary to calculate the absolute value of the signal every time and switch the switching switch according to the difference between the absolute values as in the conventional case. The responsiveness of the operation of adding is excellent. According to the first aspect of the present invention, the emphasis signal adding circuit includes a primary and secondary differential circuit of the color difference signal, a subtractor, and an emphasis signal level variable circuit. According to the invention, the color difference signal delay circuit, the subtractor and the adder for adding and subtracting the delay signal, and the emphasis signal level variable circuit are included. Therefore, even if the edge portion of the signal becomes dull in the signal processing and color bleeding occurs at the color boundary portion, the rising and falling edges of the color signal waveform are sharpened, and the configuration is simple and inexpensive.

[0009]

EXAMPLES Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. In FIG. 1, the contour correction device 11
Is a color demodulation circuit 12 that demodulates the color signal e into RY and BY color difference signals a, and an emphasis signal addition circuit 25 that adds emphasis signals before and after each of the demodulated color difference signals abruptly changes. , 26 and these emphasized signal adding circuits 25, 2
The color difference signal to which the emphasis signal is added by 6 is the color signal f
And a color modulation circuit 19 for One of the emphasis signal adding circuits 25 adds an emphasis signal to a portion of the color difference signal RY, and the other circuit 26 of the color difference signal BY changes abruptly.

That is, in the circuit 25, 14 is a first-order differentiating circuit which first-order differentiates the color difference signal a demodulated by the color demodulating circuit 12, and 15 is second-order differentiating the first-order differentiated signal b. A differentiating circuit 16 is an amplifying circuit that makes the amplitude level of the second-order differentiated signal c variable. Reference numeral 17 denotes an amplifier level variable circuit which linearly changes the amplification level in the amplification circuit 16 according to the input DC level. Reference numeral 13 denotes a delay circuit, which delays by the total time of the primary differentiation circuit 14, the secondary differentiation circuit 15 and the amplification circuit 16. 18 is a delay circuit 13
Is a subtracter for subtracting a second-order differentiated signal from the color difference signal that has passed through the output signal d of the subtractor 18 and the color modulation circuit 19
Entered in. Since both emphasis signal adding circuits 25 and 26 have the same configuration, only the configuration of one circuit 25 will be described, and the other circuit 26 will be denoted by the same reference numeral.
The detailed description is omitted.

Next, the operation of the above configuration will be described. First, the color signal e input from the input terminal 1 is demodulated by the color demodulation circuit 12 into the RY and BY color difference signals a. When the color difference signal a is a signal as shown in FIG. 2A, for example, it is differentiated by the primary differentiating circuit 14 to obtain the waveform of the primary differential signal shown in FIG. 2B. The signal is differentiated by the secondary differentiating circuit 15 to obtain the waveform of the secondary differential signal c shown in FIG. The waveform of the secondary differential signal c is the amplifier level variable circuit 17
The amplifier circuit 16 amplifies the signals at the same level in accordance with the DC level given by. On the other hand, the original signal (a) that has passed through the delay circuit 13 is a color difference signal to which the secondary differential signal c has been subtracted by the subtractor 18 and the enhancement signal d1 has been added, as shown in FIG. Becomes

The color difference signals R-Y and B-Y which have been subjected to the signal processing as described above are added to the respective emphasis signal adding circuits 25 and 26.
Is input to the color modulation circuit 19 to be modulated into the original color signal and output from the output terminal 10 as an output signal f shown in FIG. According to the above embodiment, the color difference signal a
Since the emphasizing signal d1 is added to, the color bleeding at the boundary of the color signal is eliminated, the apparent color resolution is increased, and the color signal is improved. Moreover, the circuit is simple and inexpensive.

Embodiment 2. FIG. 3 shows another embodiment. In the figure, the same parts as those in FIG.
The detailed description is omitted. 27 is an RY color difference signal a
A first delay circuit that delays
And is delayed by the second delay circuit 28 for a predetermined time τ.
Only delayed.

Numeral 29 is a first subtractor for subtracting the signal a before being delayed from the signal b delayed by the first delay circuit 27, and numeral 30 is a signal b delayed by the first delay circuit 27. , A second subtractor for subtracting the signal c delayed by the second delay circuit 28, and 31 for the first and second subtractors 2
In the first adder for adding the signals e and f output from 9 and 30, the output signal g of the adder 31 is applied to the amplifier circuit 16 and the amplitude level of the output signal is changed, The amplifier level varying circuit 17 is configured to linearly change the level of the amplifying circuit 16 according to the DC level input to the amplifier level varying circuit 17. 32 is a second adder, which is the signal b delayed by the first delay circuit 27.
To the output signal g of the first adder.
The enhancement signal adding circuit 25 is configured as described above. The other emphasized signal adding circuit 26 has the same configuration as that of the circuit 25, and therefore its detailed description is omitted. The color difference signals output from the emphasis signal adding circuits 25 and 26 are modulated by the color modulating circuit 19 into the original color signals.

Next, the operation of the above configuration will be described. First, the color signal input from the input terminal 1 is demodulated by the color demodulation circuit 12 into color difference signals RY and BY.
For example, when the signal is as shown in FIG. 4 (a),
The color difference signal a is delayed by the first delay circuit 27 for a predetermined time τ, and further delayed by the second delay circuit 28 for a predetermined time τ to obtain a signal as shown in FIGS. Become. The signal b delayed by the first delay circuit 27 is
The first subtractor 29 subtracts the signal a before being delayed to obtain a signal as shown in FIG. Further, the signal c further delayed by the predetermined time τ by the second delay circuit 28 is subtracted from the signal b before being delayed by the second subtractor 30, as shown in FIG. It becomes a signal.

The two signals e and f are added by the first adder 31, and the output signal g of the adder 31 is applied to the amplifier circuit 16 to change the amplitude level of the output signal, and then the amplifier. The level variable circuit 17 linearly changes the level of the amplifier circuit 16 according to the DC level input thereto. The output signal of the amplifier circuit 16 is added to the signal b delayed by the first delay circuit 27,
As shown in (h) of the figure, the color difference signal is obtained by adding the enhancement signal h1. The color-difference signals R-Y and B-Y processed as described above are modulated into color signals by the color modulation circuit 19 and output as output signals from the output terminal 10 to become the original color signals.

According to the above-described embodiment, since the emphasizing signal h1 is added to the color difference signal a, the circuit is simple and inexpensive, the color bleeding at the boundary portion of the color signal is eliminated, and the apparent color Resolution is increased and the color signal is improved.

[0018]

As described above, according to the present invention, by adding the emphasis signal to the color difference signal, the color bleeding at the boundary portion of the color signal can be eliminated at a low cost with a simple circuit, and the apparent color The resolution can be increased and the color signal can be improved.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a contour correction device according to a first embodiment of the present invention.

FIG. 2 is a signal waveform diagram for explaining the operation of the first embodiment.

FIG. 3 is a block circuit diagram showing a contour correction device according to a second embodiment of the present invention.

FIG. 4 is a signal waveform diagram for explaining the operation of the second embodiment.

FIG. 5 is a block circuit diagram showing a conventional contour correction device.

FIG. 6 is a signal waveform diagram for explaining the operation of the conventional example.

[Explanation of symbols]

 11 Contour Correction Device 12 Color Demodulation Circuit 13 Delay Circuit 14 Primary Differentiation Circuit 15 Secondary Differentiation Circuit 17 Amplifier Level Variable Circuit 18 Subtractor 19 Color Modulation Circuit 25, 26 Emphasis Signal Addition Circuit 27 First Delay Circuit 28 Second Delay circuit 29 First subtractor 30 Second subtractor 31 First adder 32 Second adder

[Procedure amendment]

[Submission date] April 2, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

Means for Solving the Problems] The inventors of the first claims, the enhancement signal adding circuit, and second-order differential circuit you secondary differential color-difference signals, the second differentiated signal from the original color difference signals It is characterized by comprising a subtractor and a subtraction circuit, and an emphasis signal level changing circuit for changing the amplitude level of the emphasis signal. In the invention according to claim 2, the emphasis signal adding circuit is
First and second delay circuits for delaying the color difference signals by a predetermined time, a first subtractor for subtracting a signal before being delayed from a signal delayed by the first delay circuit, and a first delay circuit Second subtractor for subtracting the signal delayed by the second delay circuit from the signal delayed by, the adder for adding the signals output from the first and second subtractors, and the output of this adder It is characterized by comprising an adder for adding a signal to the output signal of the first delay circuit and an emphasis signal level variable circuit for changing the amplitude level of the emphasis signal.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010] That is, in the circuit 25, 15 is second-order differential circuit for second derivative of the chrominance signal a demodulated by the color demodulation circuit 12, 16 is amplified to the amplitude level of the secondary differentiated signal c is variable Circuit. Reference numeral 17 denotes an amplifier level variable circuit which linearly changes the amplification level in the amplification circuit 16 according to the input DC level. 13 is a delay circuit, in which delaying time of the sum of the upper Symbol secondary differential circuit 15 and the amplification circuit 16. Reference numeral 18 denotes a subtractor for subtracting a signal that has been secondarily differentiated from the color difference signal that has passed through the delay circuit 13. The output signal d of the subtractor 18 is input to the color modulation circuit 19. Since both emphasis signal adding circuits 25 and 26 have the same configuration, one circuit 2
Only the configuration of No. 5 will be described, the other circuit 26 will be denoted by the same reference numeral, and detailed description thereof will be omitted.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

Next, the operation of the above configuration will be described. First, the color signal e input from the input terminal 1 is demodulated by the color demodulation circuit 12 into the RY and BY color difference signals a. The color difference signal a when a signal as shown in example FIG. 2 (a), the by second-order differential circuit 15
The second derivative signal c is obtained by second derivative and is shown in FIG.
Waveform. The waveform of the secondary differential signal c is amplified by the amplifier circuit 16 at the same level according to the DC level given from the amplifier level variable circuit 17. On the other hand, the original signal (a) that has passed through the delay circuit 13 is
The secondary differential signal c is subtracted by
As shown by, the color difference signal is obtained by adding the enhancement signal d1.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing a contour correction device according to a first embodiment of the present invention.

FIG. 2 is a signal waveform diagram for explaining the operation of the first embodiment.

FIG. 3 is a block circuit diagram showing a contour correction device according to a second embodiment of the present invention.

FIG. 4 is a signal waveform diagram for explaining the operation of the second embodiment.

FIG. 5 is a block circuit diagram showing a conventional contour correction device.

FIG. 6 is a signal waveform diagram for explaining the operation of the conventional example.

[EXPLANATION OF SYMBOLS] 11 contour correcting device 12 color demodulating circuit 13 delays circuits 1 5 second-order differential circuit 17 amplifier level variable circuit 18 subtractor 19 color modulation circuit 25, 26 enhancement signal adding circuit 27 first delay circuit 28 first 2 delay circuit 29 first subtractor 30 second subtractor 31 first adder 32 second adder

[Procedure correction 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (2)

[Claims] 1. A color for demodulating a color signal into a color difference signal.
A demodulation circuit, an emphasis signal addition circuit for adding an emphasis signal before and after each of the demodulated color difference signals suddenly changes, and a color modulation for modulating the color difference signal to which the emphasis signal is added by the emphasis signal addition circuit into a color signal. The enhancement signal adding circuit includes a circuit, and a primary differentiating circuit that first-differentiates the color difference signal, a second-order differentiating circuit that further differentiates the first-order differentiating signal, and a second-order differentiating from the original color difference signal. A contour correction apparatus comprising: a subtractor for subtracting a signal; and an emphasis signal level changing circuit for changing the amplitude level of the emphasis signal. 2. A color for demodulating a color signal into a color difference signal.
A demodulation circuit, an emphasis signal addition circuit for adding an emphasis signal before and after each of the demodulated color difference signals suddenly changes, and a color modulation for modulating the color difference signal to which the emphasis signal is added by the emphasis signal addition circuit into a color signal. The enhancement signal adding circuit includes a first delay circuit and a second delay circuit for delaying the color difference signal by a predetermined time, and a signal before being delayed from the signal delayed by the first delay circuit. From the signal delayed by the first subtractor and the first delay circuit to the second
Second subtractor for subtracting the signal delayed by the delay circuit, the adder for adding the signals output from the first and second subtractors, and the output signal of the adder for the first delay circuit. A contour correction device comprising: an adder added to an output signal; and an emphasis signal level changing circuit for changing the amplitude level of the emphasis signal.