JPH0362682A - Ghost elimination device with noise canceller - Google Patents

Abstract

PURPOSE:To reduce the time till ghost is eliminated by controlling the device such that a signal during noise processing is outputted before noise elimination by a noise elimination circuit is finished and starting the setting of a filter coefficient based on the signal. CONSTITUTION:A video signal is inputted to an 8-field arithmetic circuit 7. The circuit 7 calculates the ghost elimination reference signal for each 8-field sequence. A noise elimination circuit 8 outputs forcibly a signal subject to noise elimination on its halfway before the noise is completely eliminated when the circuit 8 applies arithmetic mean processing to a signal calculated by the circuit 7 for many number of times and its signal sets the coefficient of a filter. Thus, a proper control signal is sent from a control means 20 to the circuit 8 and a filter coefficient setting circuit 12 to apply the processing as above thereby controlling the transmission timing of a noise elimination signal and the filter coefficient. Thus, the ghost signal is eliminated on its halfway without awaiting the end of noise elimination.

Description

Detailed Description of the Invention "Field of Industrial Application" This invention provides a ghost removal system with a noise canceller that removes ghost signals from a video signal by using a noise removal reference signal inserted into video No. 43. Regarding equipment.

"Prior Art" A ghost removal device with a noise canceller is known that uses a noise removal reference signal (OCR signal) inserted into the video signal to remove ghost eye No. 8 from the video signal.

OCR (No. 8) is inserted into the vertical retrace period of the video signal as shown in FIG. 2, and its rising waveform has a 5inX/X pulse characteristic, and its rising edge has a 2T pulse characteristic. As shown in Figure 2, the O pedestal waveform inserted every two fields has the same setup as the OCR waveform, and these two signals are repeatedly sent out every 8 fields as shown in the figure. OCR (No. 8 is inserted into the 1st, 3rd, 6th, and 8th fields, and the O pedestal signal is inserted into the 2nd, 4th, 5th, and 7th fields, respectively.

FIG. 4 shows a ghost removal device with a noise canceller that removes ghosts using the above-mentioned OCR signal.

A video signal input from the video signal input terminal 1 is input to an adder 2 and an 8-field arithmetic circuit 7. The input signal is added to the output signal of the transversal filter 3 in the adder 2 and outputted from the video output terminal 4. The output signal of the adder 2 is input to a transversal filter 3. The initial coefficient of the transversal filter 3 is O.

A gate pulse for the OCR signal is created in the gate pulse generation circuit 6 based on the synchronization signal inputted from the synchronization number 43 input terminal 5, and this gate pulse is sent to the 8 field calculation circuit 7 and the reference signal generation circuit 10. .

The 8-field arithmetic circuit 7 processes the GCR signal part (
GCR signal and ○pedestal signal), and
In the 8-field sequence shown in the figure, add the fields of the OCR waveform, that is, the 1st and 3rd degree 6.8 fields,
O pedestal field i.e. 2nd + 4 + 5
+ Subtract 7 fields. By this calculation, Figure 3A
The synchronization signal, ghost signal, previous line signal, etc. are removed and the GCR (only No. 3 is output. This OCR
(No. 8 is input to the noise removal circuit 8.

The noise removal circuit 8 averages the signals obtained by performing the eight field calculations several dozen times. For example, if the data is averaged 32 times, 256 fields will be calculated including the 8 fields calculated by the calculation circuit 7. The output signal of the noise removal circuit 8 is differentiated by the differentiating circuit 9 as shown in FIG. 3B, and the differentiated output is input to the subtracter 11.

The reference signal generation circuit 10 generates the reference signal shown in FIG. Then, a difference signal between the differential signal subtracted by the subtracter 11 and the base 4-signal is supplied to the filter coefficient setting circuit 12.

The filter coefficient setting circuit 12 calculates and sets the coefficients of the transversal filter 3 based on the difference signal, thereby removing Go-3148.

The ghost removal range is the differential No. 13-2 shown in Figure 3B.
This is just before the T pulse.

"Problem to be Solved by the Invention" In the conventional method, ghosts are removed after noise has been completely removed, so it takes time to remove ghosts.

As mentioned above, when using the output after 32 averaging operations as the output after noise removal, 256 fields are averaged, so it takes 4 seconds before the noise removal output is output. It will take more than that. Therefore, from the time the power switch of the apparatus is turned on until that time, an image is displayed in which ghosts are not removed at all.

If the number of noise removal additions is reduced in an attempt to speed up the sending time of the noise removal signal, noise will be mistakenly detected as a ghost and malfunction will occur.

Therefore, this invention solves such problems, and without delaying the sending time of the noise removal signal,
This paper proposes a ghost removal device equipped with a noise canceler that can remove ghosts.

"Means for Solving the Problems" In order to solve the above-mentioned problems, the present invention provides an adding means for adding a video signal that has passed through a transversal filter to an input video signal to obtain an output video signal, and a ghost removal standard. 8-field calculation means for adding or subtracting field by field according to the 8-field sequence of signals; noise removal means for averaging the calculated signals to remove noise; and differentiation means for differentiating No. 13 from which noise has been removed. a reference signal generation means for generating a ghost removal reference signal; an illil budget for subtracting the differential signal and the ghost removal reference No. 43; and a filter coefficient of the transversal filter according to the difference No. 43 from the subtraction means. a filter coefficient setting means for calculating and setting; and a control means for controlling the noise removal means to output a signal during the noise removal process before the noise removal is completed; The feature is that ghosts are removed from the signal.

"Function" In this configuration, the control means 20 to the noise removal circuit 8
A control signal is sent to the noise removing circuit 8 to control the signal No. 13 which is undergoing noise removal processing to be output without waiting until the noise removal circuit 8 finishes removing the noise.

Then, the filter coefficients are started to be set based on No. 4g during this process. Specifically, at the beginning, the correction rate of the filter coefficient is made small because noise is mixed in, and as the number of times goes on and the noise is removed, the correction rate is increased, and finally, the ghost is completely removed. Set the filter coefficient to . Control of this coefficient value is also commanded by the control means 20.

Embodiment Next, a ghost removal device with a noise canceler according to the present invention will be described in detail with reference to FIG. 1 and subsequent figures.

Although the description of the same parts as those of the ghost removal device shown in FIG. 4 will be omitted, the noise removal processing operation of the noise removal circuit 8 is changed as follows. In other words, when No. 43 calculated by the 8-field calculation circuit 7 is averaged many times by the noise removal circuit 8, before the noise is completely removed, No. 43 from which the noise has been partially removed is forcibly removed. The filter coefficients are set based on that signal.

For example, by averaging 32 times and finally removing noise (3
For example, 1
The results are output every time and supplied to the differentiating circuit 9, and the filter coefficients of the filter coefficient setting circuit 12 are controlled. For example, at the beginning, the correction rate of the filter coefficients is reduced because noise is mixed in, and as the number of times goes on and the noise is removed, the correction rate of the filter coefficients is increased, and finally the ghost is completely removed. Set the filter coefficient to .

Therefore, in order to perform such a processing operation, an appropriate @ control signal is sent from the control means 20 having a built-in CPU to the noise removal circuit 8 and the filter coefficient setting circuit 12.
The exit timing of the noise removal signal and the filter coefficient value are controlled.

In the above example, the intermediate noise removal signal was output every time addition was performed, but it can also be controlled to output a noise removal signal every several additions, so the output timing is limited to the above example. I can't.

"Effects of the Invention" By doing the above, it is possible to remove ghost signals from an intermediate stage without waiting until the noise has been removed, and in the end, ghost signals are removed from the noise-removed signal. It will be removed.

Therefore, ghosts can be removed without false detection, and the time required to remove ghosts can be shortened.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of a ghost removal device with a noise canceller according to the present invention, FIG. 2 is an explanatory diagram of an 8-field sequence, FIG. 3 is an explanatory diagram of a ghost canceling operation, and FIG. FIG. 2 is a configuration diagram of a ghost removal device with a noise canceler for explanation. 3 ・ 6 ・ 7 ・ 8 ・ 9 ・ 10 ・ 12 ・ 20 ・ Transversal filter・OCR gate pulse generation circuit・8 field calculation circuit・Noise removal circuit・Differentiation circuit・Reference signal generation circuit・Filter coefficient setting circuit・control means

Claims (1)

[Claims] (1) Adding means for adding a video signal passed through a transversal filter to an input video signal to obtain an output video signal; and 8-field calculation means for adding or subtracting field by field using an 8-field sequence of a ghost removal reference signal; noise removing means for removing noise by averaging the calculated signals; differentiating means for differentiating the noise-removed signal; reference signal generating means for generating a ghost removal reference signal; and removing the differential signal and the ghost. a subtracting means for subtracting a reference signal; a filter coefficient setting means for calculating and setting a filter coefficient of the transversal filter according to the difference signal from the subtracting means; 1. A ghost removal device with a noise canceller, comprising: a control means for performing control such as outputting a signal undergoing noise removal processing, and removing a ghost using the signal undergoing noise removal processing.