JPH01212975A - Noise removal circuit - Google Patents
Noise removal circuitInfo
- Publication number
- JPH01212975A JPH01212975A JP63037838A JP3783888A JPH01212975A JP H01212975 A JPH01212975 A JP H01212975A JP 63037838 A JP63037838 A JP 63037838A JP 3783888 A JP3783888 A JP 3783888A JP H01212975 A JPH01212975 A JP H01212975A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- video signal
- noise
- mixing
- level
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
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- Picture Signal Circuits (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
「産業上の利用分野」
本発明は映像信号中のノイズを除去するためのノイズ除
去回路に関するものである。DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a noise removal circuit for removing noise in a video signal.
「従来の技術」
従来のこの種の回路は第２図に示すように構成され、入
力端子（１）より入力した映像信号を増幅回路（２）で
増幅した後、ＬＨ（水平走査期間）デレイライン（３）
でＩＨだけ遅延させた映像信号と、遅延していない映像
信号とを差動増幅回路（４）で差をとり、さらに大巾な
損失を防ぐためリミッタ（５）を通して逆位相で混合回
路（６）へ送る。この混合回路（６）にはノイズを含ん
だ映像信号が入力しているので、これらを混合すると、
出力端子（７）にはノイズを含まない映像信号が得られ
る。"Prior Art" This type of conventional circuit is configured as shown in Fig. 2, and after amplifying a video signal input from an input terminal (1) in an amplifier circuit (2), it is connected to an LH (horizontal scanning period) delay line. (3)
The difference between the video signal delayed by IH and the undelayed video signal is taken by a differential amplifier circuit (4), and in order to prevent a large loss, the video signal is output to a mixing circuit (6) with an opposite phase through a limiter (5). ). Since a video signal containing noise is input to this mixing circuit (6), when these are mixed,
A video signal containing no noise is obtained at the output terminal (7).
ｒ発明が解決しようとする課題」
しかるに、一般に相関性を利用したノイズ除去回路では
、ＬＨ遅延した映像信号と遅延していない映像信号とは
、はとんど一致して相関性があるのに対し、ノイズには
全く相関性がないことを前提としている。ところが、Ｉ
Ｈ遅れの映像信号と遅れのない映像信号は完全に一致し
ている訳ではないし、また、従来回路では特に、映像信
号とノイズとのＳ／Ｎ比が小さいときには、正常な映像
信号が削られて歪が生じてしまうという問題があった・
本発明は映像信号のレベルの大きさに応じて逆相で加算
するノイズの量を制御することを可能としたノイズ除去
回路を得ることを目的とするものである。``Problem to be Solved by the Invention'' However, in general, in a noise removal circuit that uses correlation, the LH-delayed video signal and the undelayed video signal almost always match and have a correlation. On the other hand, it is assumed that noise has no correlation at all. However, I
H-delayed video signals and non-delayed video signals do not completely match, and in conventional circuits, especially when the S/N ratio between the video signal and noise is small, the normal video signal is deleted. The object of the present invention is to provide a noise removal circuit that can control the amount of noise added in reverse phase according to the level of the video signal. It is something to do.
「課題を解決するための手段」
本発明は上述の目的を達成するためになされたもので、
例えばＩＨデレイラインでＩＨ遅延した映像信号と遅延
しない映像信号との差から差動増幅回路でノイズ成分を
抽出し、このノイズ成分を、混合回路で映像信号に逆相
で混合してノイズを除去する回路において、映像信号の
信号レベルを検出する検出回路を設け、この検出回路を
、前記混合回路に設けられたノイズ成分の混合レベル制
御用混合制御部に結合し、映像信号の信号レベルに応じ
てノイズの混合レベルを制御するようにしたものである
。"Means for Solving the Problems" The present invention has been made to achieve the above-mentioned objects.
For example, a differential amplifier circuit extracts a noise component from the difference between an IH-delayed video signal and an undelayed video signal on an IH delay line, and a mixer circuit mixes this noise component with the video signal in reverse phase to remove noise. The circuit is provided with a detection circuit for detecting the signal level of the video signal, and this detection circuit is coupled to a mixing control section for controlling the mixing level of noise components provided in the mixing circuit, so that the signal level of the video signal is The noise mixing level is controlled.
「作用」
ＩＨデレイラインでＩＨ遅延した映像信号と遅延してい
ない映像信号とが差動回路へ入力してその差をとること
によってノイズ成分が抽出される。"Operation" The video signal delayed by IH and the video signal not delayed by the IH delay line are input to the differential circuit and the difference is taken, thereby extracting the noise component.
このノイズ成分は、映像信号の信号レベルが高いとき、
すなわちＳ／Ｎ比が大きいときはノイズがほとんど気に
ならないので混合回路の混合制御部の混合量を少なくし
て映像信号に逆相で加えてノイズを除去する。また、Ｓ
／Ｎ比が小さいときには、小さなノイズでも目立つので
、ノイズ成分を大きくして逆相で加えてノイズを除去す
る。This noise component is generated when the signal level of the video signal is high.
That is, when the S/N ratio is large, the noise is hardly noticeable, so the mixing amount of the mixing control section of the mixing circuit is reduced and the noise is removed by adding it to the video signal in reverse phase. Also, S
When the /N ratio is small, even small noise is noticeable, so the noise component is increased and added in reverse phase to remove the noise.
「実施例」 以下、本発明の一実施例を図面に基づき説明する。"Example" Hereinafter, one embodiment of the present invention will be described based on the drawings.
（１）は映像信号の入力端子、（２）は増幅回路、（３
）はＩＨデレイライン、（４）は差動増幅回路、（５）
はリミッタ、（７）は出力端子で、これらの構成は第２
図と変わるところはない。(1) is the input terminal of the video signal, (2) is the amplifier circuit, (3
) is the IH delay line, (4) is the differential amplifier circuit, (5)
is the limiter, (7) is the output terminal, and these configurations are the second
There is no difference from the figure.
（６）は混合回路で、この混合回路（６）は、映像信号
の入力端子（８）とノイズ成分の入力端子（９）とを有
し、この混合回路（６）には混合レベルを制御するため
の混合制御部（１０）を具備し、前記ノイズ成分の入力
端子（９）に結合されている。また、前記増幅回路（２
）の出力側には、映像信号を検波してレベルを検出する
検出回路（１１）が設けられている。(6) is a mixing circuit, and this mixing circuit (6) has an input terminal (8) for a video signal and an input terminal (9) for a noise component, and this mixing circuit (6) controls the mixing level. The mixing control unit (10) is coupled to the input terminal (9) of the noise component. Further, the amplifier circuit (2
) is provided with a detection circuit (11) that detects the video signal and detects the level.
この検出回路（１１）は増幅回路（１２）、検波ダイオ
ード（１３）、抵抗（１４）およびコンデンサ（１５）
からなり、その出力側が前記混合制御部（１０）に結合
されている。This detection circuit (11) includes an amplifier circuit (12), a detection diode (13), a resistor (14), and a capacitor (15).
The output side thereof is connected to the mixing control section (10).
以上のような回路構成において、入力端子（１）から入
力した映像信号は増幅回路（２）を経て混合回路（６）
、差動増幅回路（４）、ｌＨデレイライン（３）、検出
回路（１２）へ入力する。ＩＨデレイライン（３）でＩ
Ｈ遅延した映像信号と遅延しない映像信号が差動増幅回
路（４）で差がとられる。ＩＨ遅延した信号と遅延して
いない信号とにおいて、映像信号はほとんど同一であっ
て相関性があるため、抽出した信号に映像信号が含んで
いたとしてもわずかたけであってほとんどノイズ成分だ
けが抽出される。このノイズ成分はリミッタ回路（５）
で大巾な損失を与えないように制限して混合回路（６）
の混合制御部（ｌＯ）に逆相で入力する。In the above circuit configuration, the video signal input from the input terminal (1) is sent to the mixing circuit (6) via the amplifier circuit (2).
, differential amplifier circuit (4), IH delay line (3), and detection circuit (12). I at IH delay line (3)
The difference between the H-delayed video signal and the undelayed video signal is calculated by a differential amplifier circuit (4). The video signals in the IH-delayed signal and the undelayed signal are almost the same and have a correlation, so even if the extracted signal contains a video signal, it is only a small amount and almost only noise components are extracted. be done. This noise component is the limiter circuit (5)
Mixing circuit (6) by limiting it so as not to cause a large loss in
It is input to the mixing control unit (lO) in reverse phase.
映像信号はまた検出回路（１１）で検波されて映像信号
のレベル信号が出力する。このレベル信号が高いときは
Ｓ／Ｎ比が大きいからノイズは映像上はとんど気になら
ない、したがって、混合制御部（１０）におけるノイズ
成分の除去量を減少させて映像信号の欠落を可能な限り
少なくする。この少量のノイズ成分が混合回路（６）で
映像信号と逆相で混合されて映像信号中に含まれるノイ
ズが除去される。このようにＳ／Ｎ比が大きいときはノ
イズが完全に除去されなくともノイズの存在は無視でき
る。The video signal is also detected by a detection circuit (11) and a level signal of the video signal is output. When this level signal is high, the S/N ratio is large, so the noise is hardly noticeable on the video. Therefore, it is possible to reduce the amount of noise component removal in the mixing control section (10) and eliminate the loss of the video signal. Minimize as much as possible. This small amount of noise component is mixed with the video signal in reverse phase in a mixing circuit (6) to remove the noise contained in the video signal. When the S/N ratio is large like this, the presence of noise can be ignored even if the noise is not completely removed.
つぎに、Ｓ／Ｎ比が小さいとき混合制御部（１０）の混
合量を多くする。すると、映像信号からノイズが充分に
除去される。Next, when the S/N ratio is small, the mixing amount of the mixing control section (10) is increased. Then, noise is sufficiently removed from the video signal.
「発明の効果」
本発明は上述のように構成したので、相関性を利用した
ノイズ除去はノイズの空間分布が不自然になるという欠
点を解消し、より自然なノイズ除去が可能である。"Effects of the Invention" Since the present invention is configured as described above, noise removal using correlation eliminates the drawback that the spatial distribution of noise becomes unnatural, and more natural noise removal is possible.
第１図は本発明によるノイズ除去回路の一実施例を示す
ブロック図、第２図は従来の回路図である。
（１）・・・映像信号入力端子、（２）・・・増幅回路
、（３）・・・ＩＨデレイライン、（４）・・・差動増
幅回路、（５）・・・リミッタ回路、（６）・・・混合
回路、（７）・・・出力端子、（８）・・・映像信号入
力端子、（９）・・・ノイズ成分入力端子。
（１０）・・・混合制御部、 （１１）・・・検出回路
、 （１２）・・・増幅回路、（１３）・・・検波ダイ
オード、（１４）・・・抵抗、（１５）・・・コンデン
サ。
出願人 株式会社富士通ゼネラルFIG. 1 is a block diagram showing an embodiment of a noise removal circuit according to the present invention, and FIG. 2 is a conventional circuit diagram. (1)...Video signal input terminal, (2)...Amplification circuit, (3)...IH delay line, (4)...Differential amplifier circuit, (5)...Limiter circuit, ( 6)...Mixing circuit, (7)...Output terminal, (8)...Video signal input terminal, (9)...Noise component input terminal. (10)...Mixing control unit, (11)...Detection circuit, (12)...Amplification circuit, (13)...Detection diode, (14)...Resistor, (15)...・Capacitor. Applicant Fujitsu General Ltd.
Claims (1)
像信号との差から差動増幅回路でノイズ成分を抽出し、
このノイズ成分を、混合回路で映像信号に逆相で混合し
てノイズを除去する回路において、映像信号の信号レベ
ルを検出する検出回路を設け、この検出回路を、前記混
合回路に設けられたノイズ成分の混合レベル制御用混合
制御部に結合し、映像信号の信号レベルに応じてノイズ
の混合レベルを制御するようにしたことを特徴とするノ
イズ除去回路。(1) A differential amplifier circuit extracts the noise component from the difference between the video signal delayed by the delay line and the video signal that is not delayed.
In a circuit that removes noise by mixing this noise component with a video signal in a reverse phase in a mixing circuit, a detection circuit that detects the signal level of the video signal is provided, and this detection circuit is connected to the noise component provided in the mixing circuit. 1. A noise removal circuit, characterized in that the circuit is coupled to a mixing control section for controlling a mixing level of components, and is configured to control a mixing level of noise according to a signal level of a video signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63037838A JPH01212975A (en) | 1988-02-20 | 1988-02-20 | Noise removal circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63037838A JPH01212975A (en) | 1988-02-20 | 1988-02-20 | Noise removal circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01212975A true JPH01212975A (en) | 1989-08-25 |
Family
ID=12508672
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63037838A Pending JPH01212975A (en) | 1988-02-20 | 1988-02-20 | Noise removal circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01212975A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0435472A (en) * | 1990-05-30 | 1992-02-06 | Nec Home Electron Ltd | Video display device |
| JPH04159870A (en) * | 1990-10-23 | 1992-06-03 | Matsushita Electric Ind Co Ltd | noise reduction device |
-
1988
- 1988-02-20 JP JP63037838A patent/JPH01212975A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0435472A (en) * | 1990-05-30 | 1992-02-06 | Nec Home Electron Ltd | Video display device |
| JPH04159870A (en) * | 1990-10-23 | 1992-06-03 | Matsushita Electric Ind Co Ltd | noise reduction device |
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