JPS6245292A - Television signal processor - Google Patents

Abstract

PURPOSE:To attain the correction of a vertical outline and to minimize a delay time by performing the addition and subtraction of a portion that is easy to be affected by the change of a frequency characteristic at the charge level of a CCD. CONSTITUTION:An inputted composite color video signal (a) is added on the CCD30 and an IC40, and is delayed by 1H at a charge injecting part 31 and a main body part 33, and is added on a floating gate 36, the delayed signal and the inputted signal are added at an injecting part 33. Similarly, a signal from the injecting part 31 is subtracted from the signal from an injecting part 35. The output of the gate 36 is added 52 through an inverter 46 and through an LPF53, it is changed to the signal component only of an edge part, is inputted to an injecting part 32, and the delay signal and the edge component are added, and formed to a signal on which an overshoot is attached, and added on the signal from the injecting part 33. The signal and the output of the LPF53 are subtracted at an extracting part 34 to become a luminance signal on which a preshoot and the overshoot are attached. Also, the input signal and the 1H delay signal are subtracted at an extracting part 35, a chrominance signal component is taken out through a BPF56.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention utilizes a charge transfer device such as a CCD or BBD as a delay line to perform vertical contour correction in an image projection system such as a color television receiver. The present invention relates to a television signal processing device which can also constitute a comb-shaped filter.

[Technical background of the invention]

Generally, as a means to improve the sharpness of a television image, a method of adding preshoot or overshoot to the edge portions of a video signal is known. Horizontal contour correction is the application of this preshoot and overshoot to the horizontal direction of the image, and the mainstream is generally one that uses a second-order differential circuit. Further, vertical contour correction is the application of preshoot and overshoot to the vertical direction of the image. To correct vertical contours.

Normally, a signal from one horizontal scanning period (1H) is required, and 1H
A delay line is used. In order to provide not only preshoot but also overshoot, a circuit that uses two 1H delay lines is common.

In addition, some color television receivers use a comb filter for Y/C separation, that is, separation of carrier color signals and luminance signals, and a 1H delay line is also used for this comb filter. There is.

Therefore, as mentioned above, for vertical contour correction, two
In addition, if one H delay line is used for each comb filter, the circuit configuration will be complicated, and especially if the L H delay line is constructed using CCD, BBD, etc., the circuit will be large-scale and uneconomical. It just becomes.

Therefore, a circuit for constructing vertical contour correction and a comb filter using only one 1H delay line was proposed by the applicant of the present patent, and is disclosed in Japanese Patent Application No. 58-221395.

An example of the circuit is shown in FIG. 4, and its structure and operation will be briefly explained with reference to the waveform diagram in FIG.

In FIG. 4, a composite color video signal (FIG. 5a) is supplied to an input terminal (11) and is applied to a delay circuit (12) with a delay time (TE). The output of this delay circuit (12) (Fig. 5b) is passed through an adder (13) for a delay time (1H
-τ) to the delay line (14), and its output is delayed by IH with respect to the input signal (a) as shown in FIG. 5(C). The waveform shown in FIG. 5(C) is further delayed by the delay circuit (15) with a delay time (-) to become the waveform shown in FIG. 5(d).
The signal is inverted and added to the input signal (a) by an adder (17), and as shown in FIG.
A signal containing is extracted. The waveform in FIG. 5(C) has the color signal component removed by the low-pass filter (18).
As shown in f), only the edge component (el) can be obtained. Note that this low-pass filter (18) has a delay time (τ), and for the signal in Fig. 5(c), The waveform is delayed by time (r).

No. 11 in Fig. 5(f) above and the output of the delay circuit (12) (
When Fig. 5(b) is added by the adder (13), Fig. 5(b)
'), the waveform has overshoots (χl) and (χ2), and the signal (b') has a delay line (1
4), when delayed by the delay circuit (15), Fig. 5(d')
The waveform will look like this. This waveform (d') and the delay circuit (12
) (FIG. 5(b)) are further added in an adder (19) to form a waveform as shown in FIG. 5(g), and the color signal components are almost canceled out. Furthermore, this waveform (g) is transmitted to the adder (20
) and the output of the low-pass filter (18) (
f) is added to the signal inverted by the inverter (21), and the output of the adder (20) has preshoots (yl), (y2) and overshoot (χ) as shown in FIG. 5(h).
1), becomes a luminance signal marked with (χ2) and output to the output terminal (
22).

The output of the delay circuit (12) (Fig. 5b) is output from the adder (2).
4) and the output of the delay circuit (15) (Fig. 5d)
') is added to the signal inverted by the inverter (23), and the output of the adder (24) is approximately as shown in Fig. 5(i).
The color signal component is obtained and taken out to the output terminal (25).

Note that the addition of the output (f'') of the low-pass filter (18) and the output (b) of the delay circuit (12) in the adder (13) makes the level of the output (f) relative to the output (b). The output (g) of the adder (19) in the adder (20) and the inverter (21
) with the output (-f) is to add the level of the output (-f) to the output (g) at a relatively small level.

In this way, vertical contour correction with preshoot and overshoot as well as Y/C separation becomes possible.

By the way, in the circuit shown in FIG. 4 above, the delay circuit (14)
can use COD. In general, a CCD not only has the function of delaying signals as a delay circuit (but can also have the function of adding or subtracting signals in a charged state.In particular, a comb filter can be used as a delay circuit, where the delay time and signal phase are severely restricted. It is advantageous to utilize this function when configuring the circuit, etc. Therefore, the vertical contour correction circuit and comb filter shown in Fig. 4 can be used not only as a delay circuit but also to perform part of the addition and subtraction using a CCD. It is.

[Problems with background technology]

As described above, it is possible to perform addition and subtraction using a CCD, but when addition and subtraction are performed using a CCD, a delay time occurs due to the addition and subtraction. A case will be described in which the 1H delayed signal and the original signal are added.

When addition and subtraction are performed in the CCD, signals are handled in the CCD at the signal charge level. Therefore, both the 1H delayed signal and the original signal must be input to the CCD once as charges.

A manual mechanism for injecting charge into a CCD is the dynamic current injection method (dynamic current injection method).
tInjection method), diode cut-off method (Diode Cut off), potential balance method (P
ot enti atEqui 1 i brat i
on method), but all of them require transfer gates of several bits, resulting in delay time. Also, when performing addition, the charge of the original signal and the charge delayed by 1H are added in the form of a river merging, but since this merging of charges cannot be done at once, several bits of transfer gate are used. is used. Therefore, a delay time occurs here as well. In the case of subtraction, charges are extracted, but as with addition, a delay time occurs.

The delay time generated in this way is caused by superimposing the external signal on the image of the standard television signal when it has R, G, B input terminals and signal switching means for external signals, such as recent color television receivers. At the time of so-called superimposition, the timing of the synchronization signal for the external R, G, and B signals does not match the regular timing, resulting in an inconvenience that the screen becomes unstable.

In particular, the vertical contour correction shown in FIG. In order to prevent this from occurring, it is necessary to perform addition using an external circuit other than the CCD.
Increase in external circuits and temperature test of CCD.

It is also conceivable that the performance of the rectangular filter and vertical contour correction cannot be achieved sufficiently due to changes in frequency characteristics due to COD sampling effects.

[Purpose of the invention]

The present invention is a television signal processing circuit that can perform addition and subtraction using a CCD, and can further minimize the delay time that increases from the delay time originally present in the vertical contour correction and comb filter circuits. The purpose is to provide

[Summary of the invention]

The present invention provides means for inputting a composite color video signal as an original signal into a charge transfer device, a delay means for obtaining a composite color video signal delayed by one horizontal scanning period (1H) by the charge transfer device, and the 1H delay. a first adding means having a delay time in the addition process, and subtracting the 1H delayed signal and the original signal in the charge transfer device; and a first subtraction means having a delay time in the subtraction process, a signal extraction means for extracting a signal obtained by delaying the original signal by 1H from the charge transfer device, and a signal extracted from the Err original symbol signal recording signal extraction means. a first low-pass filter having a delay time (f) for removing and extracting color signal components from the output of the second subtraction means; a second adding means that adds the output of the first low-pass filter in the charge transfer device at a timing delayed by a time (-) from the original signal, and has a delay time in the addition process; The output of the first low-pass filter is subtracted from the output of the first adding means in the charge transfer device at a timing delayed by (1H+τ) from the original signal, and the delay time is set in the subtraction process. means for passing the output from the first subtraction means through a band-pass filter to obtain a color signal component; and passing the output from the third subtraction stage through a second low-pass filter. and means for obtaining a luminance signal component through.

Each delay time by the first and second addition means for addition and the first and third addition means for subtraction in the charge transfer device is the delay time of the first low-pass filter. (τ).

[Embodiments of the invention]

The circuit of the present invention will be explained below with reference to FIGS. 1 to 3. Note that FIG. 1 shows a specific embodiment, FIG. 2 is a block diagram isometrically representing FIG. 1 in an easy-to-understand manner, and FIG. 3 is a signal waveform diagram for explaining the operation.

In FIG. 1, (40) is an integrated circuit including a charge transfer device (30) such as a CCD, and a signal input terminal (41)
, (42 signal output terminals (43), (44), (4
5), and a composite color video signal is supplied to the input end (41) from the terminal (51).

C0D (30) is a charge injection part (addition part) (31),
(32), (33) and charge extraction section (subtraction section) C34
), (35), and a floating gate (3
6). In addition, charge extraction parts (34), (35)
In order to show that these are subtracting sections, an inverter signal is written in front of them.

Here, there are transfer electrodes (N...) for a 1H delay between the charge injection parts (31) and (33). (Similarly, there are transfer electrodes (N...) for 1H between the charge injection part (31) and the charge extraction part (35).) Also, 70
-ing gate (36) is connected to the output end (43) via an inverter (46).

The video signal input to the terminal (51) is input to the input terminal (51).
41) and an adder (52), and this adder (
52) is also supplied with a signal from the output terminal (43),
The addition output is supplied to the input terminal (42) via a low-pass filter (53).

Further, the output terminal (44) is connected to a luminance signal output terminal (55) via a low-pass filter (54), and the output terminal (45) is connected to a color signal output terminal (57) via a band-pass filter (!E6). )It is connected to the. Furthermore, the first
Regarding the CCD (30) in the figure, the electrode (N...
...) The long part (body part) with a large number of electrodes is defined as a long channel (L), and the short part with a small number of electrodes attached to this long channel (L) is defined as a short channel (S),
The delay time in the long channel (L) is (1H-f),
The delay time in the short channel (S) is (r
), and to show it in an easy-to-understand isometric manner, the second
It will look like the figure. Within the frame of the integrated circuit (40) in FIG. 2, the same parts as in FIG. ). Also, the inverter shown in Figure 1 (
Since addition of the output through the output terminal (46) and the signal from the input terminal (51) essentially means subtraction, the inverter (46) and adder (52) in FIG. 1 are replaced by the subtracter (60) in FIG. )
It is shown in

Next, the operation of the circuit shown in FIG. 1 will be explained with reference to FIG.

A composite color video signal as shown in FIG. 3(a) is supplied to the input terminal (51) in FIG. 1, and is applied to the CCD (30) via the input terminal (41). And the charge injection part (31
) is delayed by time (τ) in the short channel (S) (31st Jb), and further delayed by (1H-r) in the long channel (L) in the main body part, resulting in a floating gate part (36). A signal delayed by 1H is obtained (Fig. 3C).

This 1H delayed signal (C) and the human input signal (a) are added through the charge injection section (33) to produce a luminance signal, but as can be seen from Figure 2, the 1H delayed signal is added at this addition processing stage. The human signals are each added after being delayed by a delay time (τ). In other words, when viewed from the input terminal (41), (1H+
f) The delayed signal (FIG. 3d) is added to the signal delayed by (τ).

Similarly, the image input from the charge injection unit (31)
is delayed by 1H and subtracted from the manually inputted signal from the charge injection unit (35) to produce a color signal.As can be seen from Fig. 2, even at this subtraction processing stage, the 1H delayed signal and the input signal each have a delay time (τ). are added with a delay.

On the other hand, the output from the floating gate (36) is 1H from the original human power signal including the delay time of the inverter (46).
The signal is inverted and taken out as a delayed signal at the output terminal (43), added in an adder (52), and the edge portion component including the color signal component is taken out (FIG. 3e). By passing this signal e through a low-pass filter (53), the color signal component is removed, and only the signal component at the edge portion is obtained (FIG. 3f).

This signal f is then passed through the input end (42) to the CCD (3).
0) is manually applied to the charge injection unit (32).

In this charge injection section (32), the above-mentioned (-) delayed video signal (Fig. 3b) and the edge component (Fig. 3f) are added, but both signals are also separated from Fig. 2. As shown in FIG. 3, there is a delay of time (.tau.) in this addition processing step, and the signals are added, resulting in a signal with overshoots (.chi.1) and (.chi.2) as shown in FIG. 3b'.

This signal (b') is delayed in the long channel (L) of the C0D (30), and is further added to the human input signal passed through the charge injection section (33) (Fig. 3g). ) and a low-pass filter (53
) is subtracted from the output (Fig. 3 f) in the charge extraction section (311), but as can be seen from Fig. 2, there is a time delay (τ) in the subtraction process for both signals. (Figure 3h). this? As a result of the AX2 calculation, a luminance signal with preshoots (yl), (y2) and overshoots (χ1), (χ2) added to the signal (h) obtained at the output terminal (44) is obtained. Since this luminance signal contains the color signal of the stripped earth, it is passed through a low-pass filter (54) to remove the color signal, and a luminance signal with an emphasized vertical contour is obtained at the output terminal (55). be able to. And if the delay time caused by the low-pass filter (54) is (T1),
The luminance signal at the output terminal (55) has a time delay of 1vr-t-2τ+TI with respect to the luminance signal at the input terminal (51).

Further, in the charge extracting section (35), the human video signal (Fig. 3a) and the video signal delayed by 1H (Fig. 3C) are subtracted, but there is also a delay in time (t) at this subtraction processing stage. is generated and subtracted, and the output end (45) shows as shown in Fig. 3 (1).
An output signal containing mainly color signal components is obtained.

This output signal (i) is passed through a bandpass filter (56) to extract only the color signal component, but if the delay time caused by this bandpass filter (56) is (T2), then the output terminal (57) The color signal has a delay time (TI) of (1) to some extent with respect to the original signal at the input terminal (51). If selected, the temporal timing of the luminance and color signals can be matched.

In addition, only (-) of the delay time (1H+2°τ) of the vertical contour correction and comb filter can be absorbed.

Therefore, the influence of the delay time of the comb filter circuit on vertical contour correction is only the influence of the delay time (τ) that this circuit originally has.

There is no influence of delay associated with each addition and subtraction by the CCD.

〔Effect of the invention〕

According to the television processing device of the present invention (No. It is possible to absorb delays associated with addition and subtraction in the device.

In addition, since addition and subtraction of parts that are easily affected by delay time, CCD temperature drift, and changes in frequency characteristics due to sampling effects I are performed at the CCD charge level, the effects can be minimized. , the performance of the circuit can be fully demonstrated.

[Brief explanation of drawings]

FIG. 1 shows a television signal processing device of the present invention.
・The circuit diagram shown in Figure 2 is an isometric representation of Figure 1.
The block diagram and FIG. 3 are I for explaining the operation of the present invention.
J waveform diagram, FIG. 4 is a circuit diagram showing a conventional vertical contour correction device, and FIG. 5 is a signal (skin shape diagram) for explaining the operation of FIG. 4. Heavy load transfer devices such as (3
1), (32), (33)...Charge injection section (addition stage) (34), (35)...Charge extraction section (subtraction stage) (52)... ...Adder (53), (54) ...Low-pass filter (56) ...Band-pass filter agent Patent attorney Noriyuki Chika Yudo Hirodai Uji 3 Teeth-D a, , + J) Figure 4 Figure 5

Claims (2)

[Claims] (1) means for inputting a composite color video signal as an original signal to a charge transfer device; a delay means for obtaining a composite color video signal delayed by one horizontal scanning period (1H) by the charge transfer device; a first adding means having a delay time in the addition process, and subtracting the 1H delayed signal and the original signal in the charge transfer device; , a first subtracting means having a delay time in the subtraction process; a signal extracting means for extracting a signal obtained by delaying the original signal by 1H from the charge transfer device; and a signal extracting between the original signal and the signal extracted from the signal extracting means. a second subtracting means having no delay time for performing subtraction; a first low-pass filter having a delay time (τ) for removing and extracting color signal components from the output of the second subtracting means; a second adding means that adds the output of the first low-pass filter in the charge transfer device at a timing delayed by a time (τ) from the original signal, and has a delay time in the addition process; The output of the first low-pass filter is subtracted from the output of the first addition means in the charge transfer device at a timing delayed by (1H+τ) from the original signal, and the subtraction process has a delay time. third subtracting means; means for passing the output from the first subtracting means through a band-pass filter to obtain a color signal component; and passing the output from the third subtracting means through a second low-pass filter. and means for obtaining a luminance signal component using the charge transfer device, each delay time by the first and second addition means performing addition and the first and third subtraction means performing subtraction in the charge transfer device; A television signal processing device configured to set the delay time (τ) to be equal to the delay time (τ) of the first low-pass filter. (2) Delay time due to the bandpass filter (T
_2), the television signal processing according to claim 1, wherein the delay time (T_1) by the second low-pass filter is set to T_1 = (T2 - τ). Device.