JPS6161572A - Comb-line filter - Google Patents
Comb-line filterInfo
- Publication number
- JPS6161572A JPS6161572A JP59183071A JP18307184A JPS6161572A JP S6161572 A JPS6161572 A JP S6161572A JP 59183071 A JP59183071 A JP 59183071A JP 18307184 A JP18307184 A JP 18307184A JP S6161572 A JPS6161572 A JP S6161572A
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- Prior art keywords
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- signal
- subtracter
- level
- correlation
- Prior art date
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Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、画像信号における雑音低減を行なうくし形
フィルタに関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a comb filter that reduces noise in image signals.
第５図は例えば特開昭５９−９４９８３号公報に示され
た従来のくし形フィルタを示すブロック図であり、第６
図はその信号波形図である。図において、１は入力輝度
信号、２は１水平走査期間（−１Ｈ）の遅延を行なうＩ
Ｈ遅延線、３はＩＨ遅延線出力、４は第１の減算器、５
はその減算器出力、６はレベル検出回路、７はその検出
信号、８は可変スレ出力、１０は可変抵抗器、１１は第
２の減算器、。FIG. 5 is a block diagram showing a conventional comb filter disclosed in, for example, Japanese Unexamined Patent Publication No. 59-94983, and FIG.
The figure is a signal waveform diagram. In the figure, 1 is the input luminance signal, and 2 is the I that delays one horizontal scanning period (-1H).
H delay line, 3 is IH delay line output, 4 is first subtractor, 5
is the subtracter output, 6 is the level detection circuit, 7 is the detection signal, 8 is the variable thread output, 10 is the variable resistor, and 11 is the second subtractor.
１２は出力信号である。12 is an output signal.
次に動作について説明する。入力輝度信号１と、ＩＨ遅
延線２を介されたＩＨ遅延線出力３とから第１の減算器
４により、減算器出力５が得られる。Next, the operation will be explained. A subtracter output 5 is obtained from the input luminance signal 1 and the IH delay line output 3 passed through the IH delay line 2 by the first subtractor 4 .
そしてこの減算器出力５は可変スレッショルド型のリミ
ッタ回路８及び可変抵抗器１０を介して、減算器１１に
供給され、入力輝度信号１より減算されて、出力信号１
２が得られる。また、入力輝度信号１はレベル検出回路
６に供給され、これにより入力輝度信号のレベルが検出
される。このレベル検出回路６からの検出信号７がリミ
ッタ回路８にそのスレッショルドレベルの可変制御信号
として供給される。This subtracter output 5 is then supplied to a subtracter 11 via a variable threshold limiter circuit 8 and a variable resistor 10, and is subtracted from the input luminance signal 1 to produce an output signal 1.
2 is obtained. The input luminance signal 1 is also supplied to a level detection circuit 6, which detects the level of the input luminance signal. A detection signal 7 from this level detection circuit 6 is supplied to a limiter circuit 8 as a variable control signal for its threshold level.
ここで、第１の減算器４により得られる減算器出力５に
は信号の高周波成分Ａとノイズ成分Ｂとが含まれており
、入力輝度信号１の垂直相関が小さい時には高周波成分
が太き（なり、相関が大きい時には高周波成分が小さく
なる。この減算器出力５はリミッタ回路８で制限され、
信号の高周波成分はレベル制限を受けるので、減算器１
１において入力輝度信号１の高周波成分の減算量が少な
くなり、垂直解像度の劣化が減少される。又、減算器出
力５のレベルは入力輝度信号１のレベルにも依存してい
るので、入力輝度信号１のレベルに応じてリミッタ回路
８のスレッショルドレベルＶ１、■２を■１°、■２゛
のように可変することによって、入力輝度信号１のレベ
ルが小さくてもリミッタ動作が行なわれ、これによりて
も垂直解像度の劣化が減少される。Here, the subtracter output 5 obtained by the first subtracter 4 contains the high frequency component A of the signal and the noise component B, and when the vertical correlation of the input luminance signal 1 is small, the high frequency component is thick ( When the correlation is large, the high frequency component becomes small.This subtracter output 5 is limited by the limiter circuit 8,
Since the high frequency components of the signal are subject to level restrictions, subtracter 1
1, the amount of subtraction of high frequency components of the input luminance signal 1 is reduced, and deterioration of vertical resolution is reduced. In addition, since the level of the subtracter output 5 also depends on the level of the input luminance signal 1, the threshold levels V1 and 2 of the limiter circuit 8 are set to 1° and 2° depending on the level of the input luminance signal 1. By varying this, the limiter operation is performed even if the level of the input luminance signal 1 is small, and this also reduces the deterioration of vertical resolution.
従来のくし形フィルタは以上のように構成されているの
で、雑音の除去を充分に行なおうとするならば、リミッ
タ回路のスレッショルドレベルをあまり下げることがで
きず、垂直解像度が損なわれるという欠点があった。Conventional comb filters are constructed as described above, so if you want to remove noise sufficiently, the threshold level of the limiter circuit cannot be lowered very much, and the drawback is that vertical resolution is impaired. there were.
この発明は、上記のような従来のものの欠点を除去する
ためになされたもので、垂直解像度を損なうことなく雑
音を低減できるくし形フィルタを提供するものである。The present invention was made to eliminate the drawbacks of the conventional filters as described above, and provides a comb filter that can reduce noise without sacrificing vertical resolution.
この発明に係るくし形フィルタは、第１の減算器出力に
高周波成分が無いときのみ該第１の減算器の出力を第２
の減算器に与えるスイッチ手段を設けたものである。The comb filter according to the present invention transfers the output of the first subtracter to the second subtracter only when there is no high frequency component in the output of the first subtracter.
This is provided with switch means for supplying the signal to the subtracter.
この発明においては、スイッチ手段が入力画像信号の高
周波成分の有無を判別し、該成分の無いときのみ第１の
減算器の出力を第２の減算器に与信号がそのまま出力信
号として出力される。In this invention, the switch means determines whether or not there is a high frequency component in the input image signal, and only when there is no high frequency component, the output of the first subtracter is applied to the second subtracter, and the signal is output as is as an output signal. .
以下、この発明の実施例を図について説明する。 Embodiments of the present invention will be described below with reference to the drawings.
第１図はこの発明の第１の発明の一実施例を示すブロッ
ク図であり、第２図はその信号波形図である。図におい
て、１は入力輝度信号（入力画像信号）、２は入力輝度
信号１を１水平走査期間（＝ＩＨ）遅延するＩ Ｈ遅延
線（遅延回路）、３は１Ｈ遅延線出力、４は入力輝度信
号１よりＩＨ遅延線出力３を減算する第１の減算器、５
はその減算器出力、６は入力輝度信号１のレベルを検出
するレベル検出回路、７はその検出信号、８は減算器出
力５を制限する可変スレッショルド型のりミンク回路、
９はリミッタ出力、１０は可変抵抗器、１１は入力輝度
信号１より減算信号を減算する第２の減算器、１２はそ
の出力信号である。FIG. 1 is a block diagram showing an embodiment of the first aspect of the present invention, and FIG. 2 is a signal waveform diagram thereof. In the figure, 1 is the input luminance signal (input image signal), 2 is the IH delay line (delay circuit) that delays the input luminance signal 1 by one horizontal scanning period (=IH), 3 is the 1H delay line output, and 4 is the input a first subtractor for subtracting the IH delay line output 3 from the luminance signal 1;
is the output of the subtracter, 6 is a level detection circuit that detects the level of the input luminance signal 1, 7 is the detection signal, 8 is a variable threshold type Norimink circuit that limits the subtracter output 5,
9 is a limiter output, 10 is a variable resistor, 11 is a second subtracter that subtracts a subtraction signal from the input luminance signal 1, and 12 is its output signal.
また１３は上記検出信号７を用いて減算器出力５中の高
周波成分の有無を検出する相関検出回路、１４はその相
関検出信号、１５はこの相関検出信号１４によりオンあ
るいはオフされるアナログスイッチ（以下Ａ−３Ｗと称
す）であり、これにより上記検出信号１４のないときの
み上記リミッタ出力９が減算信号として上記減算器１１
に与えられるものである。なお３０は上記１３．１５に
より構成されたスイッチ手段である。13 is a correlation detection circuit that uses the detection signal 7 to detect the presence or absence of a high frequency component in the subtracter output 5; 14 is the correlation detection signal; 15 is an analog switch that is turned on or off by the correlation detection signal 14; (hereinafter referred to as A-3W), so that the limiter output 9 is sent to the subtracter 11 as a subtraction signal only when the detection signal 14 is not present.
It is given to Note that 30 is a switch means constituted by 13.15 above.
次に動作について説明する。Next, the operation will be explained.
２ この第１図において、減算器出力５は、
入力輝度信号１に垂直相関のない部分（信号の垂直方向
ベルが大きくなる。そこで減算器出力５のレベルが、あ
るスレッショルドレベルＳＬ、Ｓ２以上になった時、相
関がなくなったものと判断し、相関検出回路１３によっ
て相関検出信号１４を出力する。相関検出回路１３のス
レッショルドレベルＳ１．３２はレベル検出回！ｅ ６
より出力された検出信号７によって制御され、入力輝度
信号のレベルが小さい時はＳｌ’、３２’ のように変
化して該入力輝度信号レベルの大小にかかわらず正確に
相関の有無を判別するように設定される。相関検出回路
１３は相関がない場合にはＡ−３ＷＩ ５をオフにして
入力輝度信号１を出力信号１２とし、これにより垂直解
像度の劣化を防止する。一方、相関がある場合にはＡ−
３ＷＩ ５をオンしてくし形フィルタとして動作させ、
雑音の低減を図るように制御する。2 In this Figure 1, the subtracter output 5 is
A portion where there is no vertical correlation in the input luminance signal 1 (the vertical direction of the signal increases. Therefore, when the level of the subtractor output 5 exceeds a certain threshold level SL, S2, it is determined that the correlation has disappeared, A correlation detection signal 14 is output by the correlation detection circuit 13.The threshold level S1.32 of the correlation detection circuit 13 is the level detection time!e6
When the level of the input luminance signal is small, it changes as shown in Sl', 32' so that the presence or absence of correlation can be accurately determined regardless of the magnitude of the input luminance signal level. is set to When there is no correlation, the correlation detection circuit 13 turns off the A-3WI 5 and uses the input luminance signal 1 as the output signal 12, thereby preventing deterioration of vertical resolution. On the other hand, if there is a correlation, A-
Turn on 3WI 5 to operate as a comb filter,
Control is performed to reduce noise.
なお、上記実施例では、通常のくし形フィルタの回路に
ついて示したが、本発明は帰還型のくし形フィルタに通
用してもよい。In the above embodiment, a normal comb filter circuit is shown, but the present invention may also be applied to a feedback type comb filter.
第３ＦｙＪはこのような帰還型のくし形フィルタに通用
した本発明の第２の発明の一実施例を示す。3rd FyJ shows an embodiment of the second aspect of the present invention which is applicable to such a feedback type comb filter.
図において、１は入力輝度信号、２は出力信号１２をＩ
Ｈ遅延するＩＨ遅延線、３はＩＨ遅延線出力、４は出力
信号１２よりＩＨ遅延線出力３を減算する第１の減算器
、５はその減算器出力、６はレベル検出回路、７は検出
信号、９はリミッタ出力、１１は入力輝度信号１より減
算信号を減算する第２の減算器、１３は相関検出回路、
１４は相関検出信号、１５はＡ−３Ｗ、１６は帰還ルー
プのゲインを決定し、これにより本フィルタの特性を可
変できる可変抵抗器、１７はリミッタ回路である。In the figure, 1 indicates the input luminance signal, and 2 indicates the output signal 12.
3 is the IH delay line output, 4 is the first subtractor that subtracts the IH delay line output 3 from the output signal 12, 5 is the output of the subtracter, 6 is the level detection circuit, 7 is the detection 9 is a limiter output, 11 is a second subtracter that subtracts the subtraction signal from the input luminance signal 1, 13 is a correlation detection circuit,
14 is a correlation detection signal, 15 is A-3W, 16 is a variable resistor that determines the gain of the feedback loop and can thereby vary the characteristics of this filter, and 17 is a limiter circuit.
この実施例回路の各部の動作波形は、はぼ第２図と同様
になるものである。The operating waveforms of each part of this embodiment circuit are essentially the same as those shown in FIG.
また本発明は入力画像信号と遅延回路の出力信号とを加
算する構成を有するくし形フィルタに適用してもよい。Further, the present invention may be applied to a comb filter having a configuration of adding an input image signal and an output signal of a delay circuit.
第４図はこのような構成の回路に適用した本発明の第３
の発明の一実施例を示す０図において、２２は遅延線出
力３を増幅する増幅器であり、そのゲインを調節するこ
とにより本フィルタの特性を可変できるものである。１
日は入力輝度信号１と増幅器２２出力とを加算する加算
回路、２０は加算出力１９を減衰し入力輝度信号１と同
じレベルの正規化加算出力２１を出力する可変抵抗器（
減衰器）、４は入力輝度信号１より上記正規化加算出力
２１を減算する第１の減算器である。FIG. 4 shows the third embodiment of the present invention applied to a circuit with such a configuration.
In FIG. 0 showing an embodiment of the invention, 22 is an amplifier for amplifying the delay line output 3, and the characteristics of this filter can be varied by adjusting its gain. 1
20 is an addition circuit that adds the input luminance signal 1 and the output of the amplifier 22, and 20 is a variable resistor that attenuates the addition output 19 and outputs the normalized addition output 21 at the same level as the input luminance signal 1.
Attenuator), 4 is a first subtracter that subtracts the normalized addition output 21 from the input luminance signal 1.
この実施例回路においてもその各部の動作波形は第２図
と同様になる。In this embodiment circuit as well, the operating waveforms of each part are similar to those shown in FIG.
なお、上記実施例においては、入力信号が輝度信号の場
合について説明したが、これは色信号であワてもよく、
上記実施例と同様の効果を奏する。Note that in the above embodiments, the case where the input signal is a luminance signal has been described, but this may also be a color signal.
The same effects as in the above embodiment are achieved.
さらに、上記実施例においては、ＩＨ遅延線を用いたく
し形フィルタについて示したが、ＩＨの整数倍の遅延線
を用いてもよい。Further, in the above embodiment, a comb filter using an IH delay line is shown, but a delay line that is an integral multiple of the IH may be used.
さらに、上記実施例ではリミッタ回路を有するものにつ
いて示したが、このリミッタ回路はなくてもよい。Furthermore, although the above embodiments are shown as having a limiter circuit, this limiter circuit may not be provided.
また、本発明は第３．第４図のものに限らず、どのよう
な（し形フィルタにも適用できるものである。Further, the present invention is directed to the third aspect. The present invention is not limited to the one shown in FIG. 4, and can be applied to any type of rectangular filter.
以上のように、この発明によれば、入力信号の高周波成
分の有無を検出し、これの無いときのみ本来のくし形フ
ィルタとして動作させるようにしたので、入力信号の垂
直解像度を損なうことなく、雑音を低減することができ
る効果がある。As described above, according to the present invention, the presence or absence of a high frequency component in an input signal is detected, and the comb filter operates as the original comb filter only when there is no high frequency component, so the vertical resolution of the input signal is not impaired. This has the effect of reducing noise.
第１図はこの発明の第１の発明の一実施例による（し形
フィルタを示すブロック図、第２図はその信号波形図、
第３図はこの発明の第２の発明の一実施例を示すブロッ
ク図、第４図はこの発明の第３の発明の一実施例を示す
ブロック図、第５図は従来のくし形フィルタを示すブロ
ック図、第６図はその信号波形図である。
図において、１は入力輝度信号（入力画像信号）、２は
ＩＨ遅延線（遅延回路）、ＪはＩＨ遅延線出力、４は第
１の減算器、５は減算器出力、６はレベル検出回路、７
は検出信号、８は可変スレッショルド型のリミッタ回路
、９はリミッタ出力、１０は可変抵抗器、１１は第２の
減算器、１２は出力信号、１３は相関検出回路、１９は
相関検出信号、１５はアナログスイッチ、１６は帰還ル
ープのゲインを決定する可変抵抗器、１７はリミッタ回
路、１８は加算器、１９は加算出力、２０は可変抵抗器
（減衰器）、２１は正規化加算出力、３０はスイッチ手
段である。
なお図中同一符号は同−又は相当部分を示す。FIG. 1 is a block diagram showing a rectangular filter according to an embodiment of the first invention, FIG. 2 is a signal waveform diagram thereof,
Fig. 3 is a block diagram showing an embodiment of the second invention of the present invention, Fig. 4 is a block diagram showing an embodiment of the third invention of the invention, and Fig. 5 shows a conventional comb filter. The block diagram shown in FIG. 6 is a signal waveform diagram. In the figure, 1 is the input luminance signal (input image signal), 2 is the IH delay line (delay circuit), J is the IH delay line output, 4 is the first subtracter, 5 is the subtracter output, and 6 is the level detection circuit. ,7
1 is a detection signal, 8 is a variable threshold limiter circuit, 9 is a limiter output, 10 is a variable resistor, 11 is a second subtracter, 12 is an output signal, 13 is a correlation detection circuit, 19 is a correlation detection signal, 15 is an analog switch, 16 is a variable resistor that determines the gain of the feedback loop, 17 is a limiter circuit, 18 is an adder, 19 is an addition output, 20 is a variable resistor (attenuator), 21 is a normalized addition output, 30 is a switch means. Note that the same reference numerals in the figures indicate the same or equivalent parts.
Claims (6)
延回路と、該入力画像信号より上記遅延回路の出力を減
算する第１の減算器と、上記入力画像信号より減算信号
を減算しその出力をフィルタの出力信号とする第２の減
算器と、上記第１の減算器の出力の高周波成分の有無を
判定し該高周波成分の無いときは該第１の減算器の出力
を上記減算信号として上記第２の減算器に与えるスイッ
チ手段とを備えたことを特徴とするくし形フィルタ。(1) a delay circuit that delays an input image signal by an integral multiple of the horizontal scanning period; a first subtracter that subtracts the output of the delay circuit from the input image signal; and a first subtracter that subtracts the output of the delay circuit from the input image signal; a second subtracter whose output is the output signal of the filter; and a second subtracter that determines the presence or absence of a high frequency component in the output of the first subtracter, and when there is no high frequency component, the output of the first subtracter is used as the subtracted signal. and switch means for supplying the signal to the second subtractor.
を用いて上記高周波成分の有無を判定するものであるこ
とを特徴とする特許請求の範囲第１項記載のくし形フィ
ルタ。(2) The comb filter according to claim 1, wherein the switch means determines the presence or absence of the high frequency component using the level of the input image signal.
遅延する遅延回路と、上記出力画像信号より上記遅延回
路の出力を減算する第１の減算器と、フィルタの入力画
像信号より減算信号を減算しその出力を上記出力画像信
号とする第２の減算器と、上記第１の減算器の出力の高
周波成分の有無を判定し該高周波成分の無いときは該第
１の減算器の出力を上記減算信号として上記第２の減算
器に与えるスイッチ手段とを備えたことを特徴とするく
し形フィルタ。(3) a delay circuit that delays the output image signal of the filter by an integral multiple of the horizontal scanning period, a first subtracter that subtracts the output of the delay circuit from the output image signal, and a subtracted signal from the input image signal of the filter; a second subtracter that performs subtraction and uses the output as the output image signal; and a second subtracter that determines whether or not there is a high frequency component in the output of the first subtracter, and when there is no high frequency component, the output of the first subtracter is A comb filter comprising switch means for applying the subtraction signal to the second subtracter.
を用いて上記高周波成分の有無を判定するものであるこ
とを特徴とする特許請求の範囲第３項記載のくし形フィ
ルタ。(4) The comb filter according to claim 3, wherein the switch means determines the presence or absence of the high frequency component using the level of the input image signal.
加算する加算回路と、該加算回路の出力信号を水平走査
期間の整数倍遅延する遅延回路と、上記加算回路の出力
信号を上記入力画像信号のレベルに合わせる減衰器と、
上記入力画像信号より上記減衰器出力を減算する第１の
減算器と、上記入力画像信号より減算信号を減算しその
出力をフィルタの出力信号とする第２の減算器と、上記
第１の減算器の出力の高周波成分の有無を判定し該高周
波成分の無いときは該第１の減算器の出力を上記減算信
号として上記第２の減算器に与えるスイッチ手段とを備
えたことを特徴とするくし形フィルタ。(5) an adder circuit that adds an input image signal and an output signal of a delay circuit (described later); a delay circuit that delays the output signal of the adder circuit by an integral multiple of the horizontal scanning period; an attenuator that matches the level of the image signal;
a first subtracter that subtracts the attenuator output from the input image signal; a second subtractor that subtracts a subtraction signal from the input image signal and uses the output as an output signal of the filter; and the first subtractor. and a switch means for determining the presence or absence of a high frequency component in the output of the subtracter and, when there is no high frequency component, supplying the output of the first subtracter to the second subtractor as the subtraction signal. Comb filter.
を用いて上記高周波成分の有無を判定するものであるこ
とを特徴とする特許請求の範囲第５項記載のくし形フィ
ルタ。(6) The comb filter according to claim 5, wherein the switch means determines the presence or absence of the high frequency component using the level of the input image signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59183071A JPS6161572A (en) | 1984-08-31 | 1984-08-31 | Comb-line filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59183071A JPS6161572A (en) | 1984-08-31 | 1984-08-31 | Comb-line filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6161572A true JPS6161572A (en) | 1986-03-29 |
Family
ID=16129238
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59183071A Pending JPS6161572A (en) | 1984-08-31 | 1984-08-31 | Comb-line filter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6161572A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0267786A2 (en) * | 1986-11-11 | 1988-05-18 | Matsushita Electric Industrial Co., Ltd. | Noise reduction apparatus for video signal |
| JPS63299578A (en) * | 1987-05-29 | 1988-12-07 | Akai Electric Co Ltd | Automatic noise canceler circuit for video signal |
| EP0398089A2 (en) * | 1989-05-15 | 1990-11-22 | Kabushiki Kaisha Toshiba | Comb filter circuit for removing noise |
| JP2012530446A (en) * | 2009-06-16 | 2012-11-29 | ソリッド テクノロジーズ インク | Radio repeater and echo signal elimination method thereof |
| US12011025B2 (en) | 2017-04-26 | 2024-06-18 | Societe Des Produits Nestle S.A. | Method for aerating a pasty product and for mixing with another product |
-
1984
- 1984-08-31 JP JP59183071A patent/JPS6161572A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0267786A2 (en) * | 1986-11-11 | 1988-05-18 | Matsushita Electric Industrial Co., Ltd. | Noise reduction apparatus for video signal |
| JPS63299578A (en) * | 1987-05-29 | 1988-12-07 | Akai Electric Co Ltd | Automatic noise canceler circuit for video signal |
| EP0398089A2 (en) * | 1989-05-15 | 1990-11-22 | Kabushiki Kaisha Toshiba | Comb filter circuit for removing noise |
| JP2012530446A (en) * | 2009-06-16 | 2012-11-29 | ソリッド テクノロジーズ インク | Radio repeater and echo signal elimination method thereof |
| US12011025B2 (en) | 2017-04-26 | 2024-06-18 | Societe Des Produits Nestle S.A. | Method for aerating a pasty product and for mixing with another product |
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