JPH0373677A - Ghost removing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention uses a ghost removal reference signal, especially long ghosts, in order to remove ghost signals from image No. 48 containing ghosts. .

[Prior Art] A ghost removal device that uses a ghost removal reference signal has been developed in order to remove a ghost signal from a video signal containing ghosts.

FIG. 4 shows an example of a ghost removal reference signal (GCR signal) inserted into a video signal to remove ghosts.

This GCR signal is a signal with an 8-field period,
As shown in the figure, it is inserted within the vertical blanking period of the video signal. In the 1st, 3rd, 6th and 8th fields, the rising edge is s
i n X / X % G whose fall has the characteristics of 2T
A CR waveform is inserted. O pedestal waveforms having the same setup as the GCR waveform are inserted into the second, fourth, fifth and seventh fields.

These two waveforms (GCR waveform and O-pedestal waveform) form an 8-field sequence that is repeatedly sent out every 8 fields as shown in the figure.

FIG. 6 shows a ghost removal device that uses this GCR signal to remove ghosts.

A video signal inputted from the video No. 48 input terminal 1 passes through a delay circuit 2 and a front ghost transversal filter 3, and an adder 4 adds the respective outputs. The output of the adder 4 is added to the output signal of the post-ghost transpersal filter 6, which is input to the next adder 5. Addition N5
The output signal of
are input respectively.

The initial coefficients of transpersal filter 3.6 are all O.
It becomes.

The GCR signal gate pulse generated by the gate pulse generation circuit 9 is sent from the synchronization signal No. 18 inputted from the synchronization signal input terminal 8 to the 8-field calculation circuit 17 and the reference signal generation circuit 14.

8 field calculation times 11? Now, the GCR (8
The number part is taken in, and the following arithmetic processing is performed.

In other words, in the 8-field sequence shown in FIG.
The fields of the CR waveform, ie, the 1st 3.6.8 field, are added, and the fields of the 0 pedestal waveform, ie, the 2.4, 5.7 fields, are subtracted.

Through this arithmetic processing, the signals that exist before and after the inserted OCR(;() (sync signal, burst signal, previous line signal, etc.) are removed, and the GC
Only the R waveform is output. This GCR waveform is the differentiator circuit 1
2 (Fig. 5B), and this differentiated signal is sent to subtractor 1.
5 is input.

On the other hand, in the reference signal generation circuit 14, the differentiating circuit 12 receives the GCR signal gate pulse from the gate pulse generation port #9.
A sinX/X pulse reference signal as shown in FIG.

Then, the subtracter 15 transmits the difference signal between the differential signal and the reference signal to the filter coefficient setting circuit 16.

The filter coefficient setting circuit 16 uses the difference signal to calculate and set the coefficients of the front ghost transpersal filter 3 and the rear ghost transpersal filter 6 to remove ghosts.

[Problems to be Solved by the Invention] By the way, in the conventional ghost removal method, as shown in FIG. 5B, a 2T pulse appears in addition to the sin In other words, only a maximum of about 44.7 μsec could be removed.

Therefore, it was not possible to completely remove long ghosts that were longer than this.

Therefore, the present invention solves these problems and proposes a ghost removal device that can also remove long ghosts.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention, a GCR waveform of a sinX/X ramp waveform, a differential waveform of a ramp waveform, and a An 8-field sequence ghost removal reference signal consisting of an O pedestal waveform is used, a sinX/X pulse is formed from the received ghost removal reference signal, and long ghosts are removed based on this sinX/X pulse. It is.

[Function] As the ghost removal reference signal inserted into the video signal, an 8-field sequence ghost removal reference signal consisting of the GCR waveform of the sinX/X ramp waveform, the differential waveform of the ramp waveform, and the 0 pedestal waveform is used ( Figure 2).

Then, using the received ghost removal reference signal,
Forms an X/X ramp waveform. Therefore, in the first 8-field arithmetic circuit 10 shown in FIG. 1, arithmetic processing of (1st to 5th) fields + (6th to 2nd) fields is performed to form a GCR waveform and a ramp differential waveform. is formed (Fig. 3B).

Also, in the second 8-field operation Ws11, (3rd -
The arithmetic processing of the 7th field+(8th-4th) field is performed, and a ramp differential waveform is output (FIG. 3C). Then, both are added.

Then, you will only have the GCR waveform (Figure 3 1)
, even long ghosts that were limited by the presence of 2T pulses can be removed.

[Example] Next, an example of a ghost removal device using a ghost removal reference signal according to the present invention will be described in detail with reference to FIG. 1 and subsequent figures. Description of parts common to the conventional example will be omitted.

In order to remove a ghost from a video signal including a ghost, in this invention, OCR4F is inserted into the video signal.
No. 4 is a GCR signal with an 8-field sequence as shown in FIG.

Then, convert this GCR signal to (1) sinX as shown in the figure.
/GCR No. 48 is an 8-field sequence consisting of the GCR waveform of the X ramp waveform (GCR ramp waveform), (2) the differential waveform of the ramp waveform (ramp differential waveform), and (3) the O pedestal waveform.

The GCR ramp waveform is inserted into the first and sixth fields, the ramp differential waveform is inserted into the third and eighth fields, and the O pedestal waveform is inserted into the second, fourth, fifth, and seventh fields, respectively. be done.

The GCR ramp waveform is a sinX/X bar waveform (see FIG. 5), and the time t;
=o, the waveform is such that it drops to the pedestal level at a rate of α per unit time Δt.

The ramp differential waveform is a waveform that is larger than the pedestal level by α until the ramp waveform drops to the pedestal level at time taO, as shown in FIGS. 2 and 3C.

An example of a ghost removal device that receives such a GCR signal and removes ghosts is shown in FIG.

In the figure, the output of the g adder 5 is sent to first and second 8-field calculation circuits 10 and 11.

The first 8-field arithmetic circuit 10 is an arithmetic circuit for obtaining only the GCR ramp waveform, and in the 8-field sequence, the 1.6th field is added and the 2nd,
5 fields are subtracted. Specifically, the following calculations are performed.

(1st - 5th) field + (6th - 2nd) field Through this arithmetic processing, only the GCR ramp waveform from which the sync signal, bar number 7148, etc. have been removed is output as shown in FIG. 3A. This calculation result is transmitted to the differentiation circuit 12.

The second 8-field arithmetic circuit 11 is an arithmetic circuit for obtaining a ramp differential waveform, and in the 8-field sequence shown in FIG. 2, the 3.8th field is added and the 4.7th field is subtracted. be done. Specifically, the following calculations are performed.

(3rd-7th) field + (8th-4th) field Through this arithmetic processing, only the ramp differential waveform from which synchronization signals, burst signals, etc. have been removed is output as shown in Figure 3C, and the signal is transmitted to the adder 13.

Differential mouth! In No. 12, the difference from a signal separated by one sample, that is, a unit time Δt, is used as a differential waveform, so that a waveform as shown in FIG. 3B is obtained. Compared to the differential waveform of the sinX/X bar in FIG. 5C, this differential waveform has a smaller value by α than the par waveform at taO as shown in FIG. 2B.

However, since the ramp differential waveform is supplied to the adder 13, by adding these two signals expressed as the GCR ramp waveform and this ramp differential waveform, α
will be corrected. As a result, a sinX/X pulse with a 2T pulse waveform removed as shown in the third diagram is obtained.

Therefore, the difference signal subtracted from the ghost reference waveform from the reference signal generation circuit 14 in the subtracter 15 becomes only the ghost component of the sinX/X pulse.

As a result, even long ghosts of approximately 44.7 μsec or longer, which were limited by the presence of the 2T pulse, can be removed.

[Effects of the Invention] As explained above, in the present invention, an 8-field sequence ghost removal reference signal is used, a sinX/X pulse is formed from the received ghost removal reference signal, and this sinX/X pulse is Ghosts are removed based on the following.

According to this method, since ghosts can be removed only by the sinX/X pulse, even long ghosts delayed by about 44.7 μsec or more, which could not be removed using the conventional technique, can be effectively and reliably removed.

[Brief explanation of drawings]

Figure 2 is an explanatory diagram of the 8-field sequence, Figure 3 is an explanatory diagram of the 8-field sequence.
The figure is a waveform diagram of the ghost removal operation, and Figure 4 is the conventional technique.
FIG. 5 is an explanatory diagram of a field sequence, FIG. 5 is an explanatory diagram of an embodiment thereof, and FIG. 6 is a configuration diagram of a ghost removal device using a conventional technique. 3 ・ 6 ・ 10 ・ 11 ・ 12 ・ 14 ◆ 16 ・ ・Front ghost transversal filter ・Back ghost transversal filter ・First 8-field arithmetic circuit ・Second 8-field arithmetic circuit ・Differential circuit・Reference signal generation circuit ・Filter coefficient setting circuit

Claims (1)

[Claims] (1) As the ghost removal reference signal inserted into the video signal, an 8-field sequence ghost removal reference signal consisting of the GCR waveform of the sinX/X ramp waveform, the differential waveform of the ramp waveform, and the 0 pedestal waveform was used and received. A ghost removal device that forms a sinX/X pulse from this ghost removal reference signal and removes long ghosts based on this sinX/X pulse.