JPS58121877A - Ghost eliminating device - Google Patents

Abstract

PURPOSE:To eliminate a ghost signal just after channel switching, by providing a memory for tap gain setting corresponding to each channel. CONSTITUTION:A ghost detection circuit 3 picks up a small section including the ghost of the front ridge of a vertical synchronizing signal from a subtractor 2 and converts the signal into a digital signal at each sampling point. An operation processing circuit 4 converts the said signal into data representing the amplitude and time location corresponding to each stage of a transversal filter 1 and conducts it to memories 6a-6n. In selecting the 1st channel, the data processed as mentioned above from a TV signal from the ghost detection circuit 3 and the circuit 4 is written in the memory 6a. The same processing is done for all the memories 6a-6n. The data of a selected memory at each channel switching is given to a tap gain switching circuit 5 via an OR gate 8 and the tap gain of each stage of the filter 1 almost at the same time of switching is set to an optimum value for the formation of the correction signal. Thus, the picture eliminating ghost is reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ghost removal device used in a television receiver C2, and in particular to a ghost removal device using a transpercent filter.

In recent years, devices using transpersal filters have been attracting attention as ghost removal devices for television receiver aircraft.

The Transpar f/I/filter is composed of a combination 6 of a charge transfer type shift register such as an OOD having an addition function and a plurality of multipliers for switching the tap gain of this shift register. The input signal is gain-loaded with t taps and delayed and added, and has the advantage of being able to simultaneously control the amplitude and delay time (ghost removal device 1: correction signal if used) in a verameter manner.

FIG. 1 shows a schematic configuration of a ghost removal device using such a transpersal filter.

That is, the composite video signal derived from the video detection circuit of the television receiver is passed through a transparsal filter (1 mouth: introduced) on the one hand, and a subtracter (2): directly introduced on the other hand. The output of is the ghost detection circuit (
314: Introduced and residual ghost component detected. Then, the amplitude and time position of the ghost component are calculated by the next arithmetic processing circuit (4), and the calculated result (-6) is changed to the tap gain switching circuit (5) by the tap gain of the transversal filter (11, that is, the tap gain of Determine the respective multipliers of the multipliers.Therefore, the transparson ν field (11
The signal output from the final sense 2 has a delay time and amplitude corresponding to the ghost component C2, and as a result, the subtractor (2
), a composite signal from which ghost components have been removed is derived.

By the way, the operation as described above (=Therefore, the tap gain of the transversal filter is a certain value ζ; convergence (2 is 1 usually takes a time V of about several seconds to 10 seconds. Therefore,
Now, if you change the channel of the Brevision receiver and there is a ghost on the new channel, the ghost detection circuit (3) and the arithmetic processing circuit (4) will operate and the ghost of that channel will be removed. until removed &
It will take a considerable amount of two hours.

In this method of updating the tap gain setting operation of the transparsal filter every time the channel is switched, a ghost appears for a while after the channel is switched, and furthermore, the channel/channel problem before the channel is changed. 2. Because of the tap gain that was set correspondingly, a correction signal that is not directly related to the channel after switching appears, and the image quality deteriorates (-).

Therefore, the present invention has been made in consideration of such points, and the details thereof (two parts will be explained below).

FIG. 2 shows a schematic configuration of a ghost removal device according to the present invention (2), and the parts corresponding to the first cause (= are given the same figure number). (1) is a transversal filter, (
2) is a subtracter, and (3) is a ghost detection circuit.

(4) is an arithmetic processing circuit, (5) is a tap gain switching circuit,
(6K) (611)-(6n) are memories consisting of RAMs provided corresponding to C2 for each television channel.

(7) is a memory selection circuit that selects one of the memories according to the channel selection signal of the television receiver, and (8) is an OR gate that guides the tap gain switching circuit (50 = be.

The ghost detection circuit (3) extracts a small section including the ghost in the front part of the signal from the vertical synchronization signal 4 from the subtracter (2) by means of the vertical synchronization signal part extraction circuit (9) C2, and outputs the output signal. The difference between the signal and a signal obtained by slightly delaying the signal is performed in the next difference circuit a, and the signal representing the amplitude and time position of the ghost component obtained by this is used in the next sampling circuit A/
The D conversion circuit aυ≦2 is designed to derive a digital signal for each sampling point by substituting two.

10,000, the arithmetic processing circuit (4) is configured to sequentially store the output signals of the sampling and A/D conversion circuit (11).
It is composed of a memory α such as M, an arithmetic unit 05 that performs autocorrelation calculation of the signal read from this memory, and a controller a4 that controls this arithmetic unit and the memory 14. The signal t - each stage of the transversal filter (11) has two corresponding amplitudes and time positions representing data (two permutations).

Note this data above! 1 (61L) (611)...
(6n) is derived (2).

Now, in the device shown in FIG.
; receives the signal from the channel selection circuit and sends it to the memory selection circuit (
7) selects memory (6K) 'L'.

Therefore, the data representing the amplitude and time position of the ghost component detected from the television signal of the s1 channel by the ghost detection circuit (3) (2) and processed as described above by the arithmetic processing circuit (40) is Memory C6 &
) &; praised. Similarly, when another channel is selected, the ghost component (:mud data) of that channel is stored in the corresponding memory in Memo 9<6&)C6b)...(6n).

In this way, note 9C6&)C6b)...(6n)
ζ represents the amplitude and time position of the ghost signal of each corresponding channel. After filling in the data, the memory selection circuit (70; The data from the selected memory (or game) 1814' is passed through the tap gain switching circuit (
5) Shini is given. Therefore, this tap gain switching circuit (5) sets the tap gain of each stage of the transversal filter (1) to the optimal value for creating a correction signal for that channel almost simultaneously with the reception of the selected channel. do. Therefore, immediately after Dhannel's movie, C2, it is possible to reproduce the image from which the ghost has been removed.

Here, separate from the power supply of the television receiver 4a main body ζ =, if the above memories (6a) (6b) - (6n) are set to 2≦2 so as to constantly provide an IE source, the power supply switch t of the television receiver can be turned on. Even if the switch is turned off, the data of each memo 9 can be retained, so even when the switch is turned on again, the image with the ghost removed will be immediately reproduced, which is convenient.

In the above description, the ghost signal detected by the ghost detection circuit (3) is converted into a digital signal (2), and this digital signal No. 11 is subjected to an autocorrelation calculation in the arithmetic processing circuit (4); The description has been made assuming that data representing the amplitude and time position of the component is calculated. However, various other methods such as cross-correlation calculation between the ghost signal and the original signal can be applied to calculate such data.

As explained above (=1) the ghost removal device of the present invention is
A ghost correction signal is created using a transversal filter, and this correction signal is combined with a television signal. A memory is provided corresponding to each television channel, and each memory stores data representing the amplitude and time position of the ghost component detected from the television signal of each channel. Therefore, there is an advantage that when the channel is switched (after the channel is switched), an image in which the ghost signal is immediately removed can be realized.

[Brief explanation of the drawing]

s1 is a diagram showing a schematic configuration of a ghost removal device using a transversal filter, and FIG. 2 is a diagram showing an embodiment of the ghost removal device according to the present invention. (31: Ghost detection circuit, (4B arithmetic processing circuit). Applicant: Sanyo Electric Co., Ltd.

Claims (1)

[Claims] +11 In an apparatus in which a correction signal is created by passing a television signal t through a transversal filter, and a ghost component is removed by combining this correction signal χ with the above-mentioned television signal, the above-mentioned transversal filter is A memo 5 for setting the tap gain is provided corresponding to each channel to every channel, and each memo 5 (= amplitude and time position data of the ghost component calculated from the television signal of each channel is stored. Ghost removal is characterized in that when each channel is received, the tap gain of each stage of the transversal filter is set according to the data C that is successively output from the corresponding memo 5. Device.