JPH02288583A - Video signal processing unit - Google Patents
Video signal processing unitInfo
- Publication number
- JPH02288583A JPH02288583A JP1109403A JP10940389A JPH02288583A JP H02288583 A JPH02288583 A JP H02288583A JP 1109403 A JP1109403 A JP 1109403A JP 10940389 A JP10940389 A JP 10940389A JP H02288583 A JPH02288583 A JP H02288583A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- level
- luminance signal
- color
- signal processing
- 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.)
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Links
- 239000002131 composite material Substances 0.000 claims description 5
- 238000001514 detection method Methods 0.000 abstract description 4
- 230000006866 deterioration Effects 0.000 abstract description 3
- 208000003443 Unconsciousness Diseases 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
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- Picture Signal Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、磁気録画再生装置等に利用される映像信号処
理装置に関し、テレビジョン画面における暗部での画質
を向上する方法を提供するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a video signal processing device used in a magnetic recording and reproducing device, etc., and provides a method for improving the image quality in dark areas on a television screen.
従来の技術
第２図は従来の映像信号処理装置の一例を示すブロック
図である。BACKGROUND OF THE INVENTION FIG. 2 is a block diagram showing an example of a conventional video signal processing device.
第２図において、入力端子１に加えられた複合映像信号
は、ＹＣ分離器２で輝度信号（Ｙ）と色信号（Ｃ）とに
分離されて各々輝度信号処理回路３と色信号処理回路４
に供給され、各々所定の処理が施された後にそれぞれ加
算器５に供給されて再び複合映像信号となり、出力端子
６に出力される。In FIG. 2, a composite video signal applied to an input terminal 1 is separated into a luminance signal (Y) and a chrominance signal (C) by a YC separator 2, and a luminance signal processing circuit 3 and a chrominance signal processing circuit 4, respectively.
After being subjected to predetermined processing, each signal is supplied to an adder 5 to become a composite video signal again, and is output to an output terminal 6.
例えばビデオテープレコーダ（以下ＶＴＲと略す）の再
生系に、第２図に示した映像信号処理装置を用いた場合
、入力端子１には再生ビデオヘッド出力信号が供給され
、ＹＣ分離器２はＦＭ変調された輝度信号を取り出すバ
イパスフィルタと低域変換された色信号を取り出すロー
パスフィルタとで構成される。また輝度信号処理回路３
はＦＭ復調器、周波数特性補正器等で構成され、色信号
処理回路４は周波数変換器、自動位相制御器等で構成さ
れる。For example, when the video signal processing device shown in FIG. 2 is used in the playback system of a video tape recorder (hereinafter abbreviated as VTR), the playback video head output signal is supplied to the input terminal 1, and the YC separator 2 It consists of a bypass filter that takes out the modulated luminance signal and a low-pass filter that takes out the low-pass converted color signal. Also, the luminance signal processing circuit 3
is composed of an FM demodulator, a frequency characteristic corrector, etc., and the color signal processing circuit 4 is composed of a frequency converter, an automatic phase controller, etc.
発明が解決しようとする課題
ここで、色信号低域変換形ＶＴＲにおいては、−数的に
輝度信号に比べて色信号のＳ／Ｎが悪いため、加算器５
の出力信号では色信号側のノイズが優勢になる。さらに
人間の目は明るい画面より暗い画面のほうがノイズに敏
感であり、またＴＶ画面の明暗のダイナミックレンジが
比較的狭いことがら、暗い画面ではＳ／Ｎが悪（しかも
黒つぶれ気味となることが多い。しかも単に黒つぶれを
軽減するために黒レベルを持ち上げると明るい画面での
コントラストが劣化するという問題がある。 課題を解
決するための手段
上記課題を解決するために、本発明の映像信号処理装置
は、複合映像信号を輝度信号と色信号とに分離するＹＣ
分離器と、分離された輝度信号のレベルを検出して制御
信号を発生するレベル検出器と、前記制御信号に応じて
前記分離された輝度信号の黒レベルを変化させるセット
アツプ切替手段と、前記制御信号に応じて分離された色
信号の飽和度を変化させる色飽和度切替手段と、前記セ
ットアツプ切替手段の該出力信号と前記色飽和度切替手
段の該出力信号とを混合して出力する加算器とを具備す
る構成としたものである。Problem to be Solved by the Invention Here, in a color signal low frequency conversion type VTR, since the S/N of the color signal is numerically lower than that of the luminance signal, the adder 5
In the output signal of , noise on the chrominance signal side becomes dominant. Furthermore, the human eye is more sensitive to noise on a dark screen than on a bright screen, and because the dynamic range of brightness and darkness on a TV screen is relatively narrow, the S/N ratio is poor on a dark screen (and the shadows tend to be crushed). Furthermore, there is a problem in that if the black level is simply raised to reduce black-out, the contrast on bright screens deteriorates.Means for Solving the ProblemsIn order to solve the above problems, the video signal processing of the present invention The device separates a composite video signal into a luminance signal and a color signal.
a separator; a level detector that detects the level of the separated luminance signal and generates a control signal; a set-up switching means that changes the black level of the separated luminance signal in accordance with the control signal; color saturation switching means for changing the saturation of the separated color signals in accordance with a control signal; and mixing and outputting the output signal of the set-up switching means and the output signal of the color saturation switching means. The configuration includes an adder.
作用
本発明は前述したような構成によって、輝度信号レベル
が比較的小さいときだけ、輝度信号の黒レベルを持ち上
げ、（例えば最大５１ＲＥ程度〉かっ色信号の飽和度を
減衰させる（最大３ｄＢ程度）ので、比較的暗い画面に
対して輪郭が見えにくくなるいわゆる黒つぶれを軽減し
、しかも色信号側のノイズによる輝度信号のＳ／Ｎ劣化
を軽減することが可能である。Function: With the above-described configuration, the present invention raises the black level of the luminance signal (for example, about 51 RE at maximum) and attenuates the saturation of the brown signal (about 3 dB at maximum) only when the luminance signal level is relatively small. It is possible to reduce so-called blackout, in which the outline of a relatively dark screen becomes difficult to see, and also to reduce S/N deterioration of the luminance signal due to noise on the color signal side.
実施例
以下本発明による映像信号処理装置の一実施例について
図面を参照しながら説明する。Embodiment Hereinafter, an embodiment of a video signal processing apparatus according to the present invention will be described with reference to the drawings.
第１図は、同実施例のブロック図を示すものであり、第
２図と同一部分については同一符号を付している。FIG. 1 shows a block diagram of the same embodiment, and the same parts as in FIG. 2 are given the same reference numerals.
第１図において、入力端子１に加えられた複合映像信号
は、ＹＣ分離器２で輝度信号（Ｙ）と色信号（Ｃ）とに
分離されて各々輝度信号処理回路３と色信号処理回路４
に供給され、各々所定の処理が施される。輝度信号処理
回路３の出力はセットアツプ切替回路７とレベル検出回
路８に供給される。レベル検出回路８は、輝度信号の平
均レベルを検出し、検出値に応じた制御信号を発生する
ものであり、数フイールド期間の平均的なレベルを検出
するように応答速度を設定する。In FIG. 1, a composite video signal applied to an input terminal 1 is separated into a luminance signal (Y) and a chrominance signal (C) by a YC separator 2, and a luminance signal processing circuit 3 and a chrominance signal processing circuit 4, respectively.
and are each subjected to predetermined processing. The output of the luminance signal processing circuit 3 is supplied to a setup switching circuit 7 and a level detection circuit 8. The level detection circuit 8 detects the average level of the luminance signal and generates a control signal according to the detected value, and its response speed is set so as to detect the average level over several field periods.
前記制御信号はセットアツプ切替回路７と色信号処理回
路４の出力に接続された色飽和度切替回路に供給されて
、輝度信号の平均レベルが大きいときは各々正規のセッ
トアツプ値と色飽和度を保持した出力信号が加算器５に
供給される。輝度信号の平均レベルが小さいときは各々
最大５１ＲＥ程度セットアツプが持ち上げられた輝度信
号出力と色飽和度が最大３ｄＢ程度減衰された色信号出
力とが加算器５に供給されて混合された後、出力端子６
に出力される。ここで、色飽和度の切替は、色バースト
信号のレベルを一定レベルに保ちなから色バースト信号
を除（色信号のレベルを切替ることによって行なう。The control signal is supplied to a color saturation switching circuit connected to the set-up switching circuit 7 and the output of the color signal processing circuit 4, and when the average level of the luminance signal is large, the normal set-up value and color saturation are changed respectively. The output signal holding the value is supplied to the adder 5. When the average level of the luminance signal is small, the luminance signal output with the set-up increased by a maximum of 51 RE and the color signal output with the color saturation attenuated by a maximum of 3 dB are supplied to the adder 5 and mixed. Output terminal 6
is output to. Here, the degree of color saturation is switched by keeping the level of the color burst signal at a constant level and then subtracting the color burst signal (switching the level of the color signal).
したがって輪郭が見えに＜＜シかもノイズが目につきや
すいとされる暗い画面に対してのみセットアツプをわず
かに持ち上げることによって黒つぶれを軽減しかつ比較
的Ｓ／Ｎが悪い色信号の色飽和度を減衰させることによ
ってＶＴＲ画面上の色の濃さを薄くするとともに加算器
５で精度信号に混入した後ＴＶ側で輝度ノイズとして見
えてしまう色信号側のノイズレベルを抑圧して、ＴＶ画
面上でのＳ／Ｎを改善することができる′。Therefore, by slightly increasing the setup only for dark screens where the outline is less visible and noise is more noticeable, it is possible to reduce the blackout and reduce the color saturation of the color signal with a relatively poor S/N ratio. By attenuating this, the color density on the VTR screen is reduced, and the noise level on the color signal side, which is mixed into the accuracy signal in the adder 5 and appears as luminance noise on the TV side, is suppressed. It is possible to improve the S/N ratio in '.
発明の効果
以上の説明から明らかなように、本発明の映像信号処理
装置は、輝度信号の平均レベルが小さいときすなわち暗
い画面に対してのみ自動的に輝度信号のセットアツプを
持ち上げるとともに色信号の色飽和度を減衰させるもの
であり、明るい画面のコントラストの劣化を招くこさな
く、暗い画面の黒つぶれの軽減とＳ／Ｎ感の向上を実現
できるという極めて有効な映像信号処理装置である。Effects of the Invention As is clear from the above explanation, the video signal processing device of the present invention automatically increases the setup of the luminance signal only when the average level of the luminance signal is small, that is, for a dark screen, and also increases the setup of the color signal. It is an extremely effective video signal processing device that attenuates the color saturation and can reduce the blackout of dark screens and improve the S/N feeling without causing deterioration of the contrast of bright screens.
第１図は本発明による映像信号処理装置の−実流側を示
すブロック図、第２図は従来の映像信号処理装置の一例
を示すブロック図である。
１・・・・・・入力端子、２・・・・・・Ｙ／Ｃ分離器
、３・・・・・・輝度信号処理回路、４・・・・・・色
信号処理回路、５・・・・・・加算器、６・・・・・・
出力端子、７・・・・・・セットアツプ切替回路、８・
・・・・・レベル検出回路、９・・・・・・色飽和度切
替回路。FIG. 1 is a block diagram showing the actual flow side of a video signal processing device according to the present invention, and FIG. 2 is a block diagram showing an example of a conventional video signal processing device. 1... Input terminal, 2... Y/C separator, 3... Luminance signal processing circuit, 4... Color signal processing circuit, 5...・・・Adder, 6・・・・・・
Output terminal, 7...Set-up switching circuit, 8.
... Level detection circuit, 9 ... Color saturation switching circuit.
Claims (1)
器と、分離された輝度信号のレベルを検出して制御信号
を発生するレベル検出器と、前記制御信号に応じて前記
分離された輝度信号の黒レベルを変化させるセットアッ
プ切替手段と、前記制御信号に応じて分離された色信号
の飽和度を変化させる色飽和度切替手段と、前記セット
アップ切替手段の該出力信号と前記色飽和度切替手段の
該出力信号とを混合して出力する加算器とを具備するこ
とを特徴とする映像信号処理装置。a YC separator that separates a composite video signal into a luminance signal and a color signal; a level detector that detects the level of the separated luminance signal and generates a control signal; and a level detector that detects the level of the separated luminance signal and generates a control signal; setup switching means for changing the black level of a signal; color saturation switching means for changing the saturation of the separated color signal according to the control signal; and switching between the output signal of the setup switching means and the color saturation switching. A video signal processing device comprising: an adder that mixes the output signal of the means and outputs the mixed signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1109403A JPH02288583A (en) | 1989-04-28 | 1989-04-28 | Video signal processing unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1109403A JPH02288583A (en) | 1989-04-28 | 1989-04-28 | Video signal processing unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02288583A true JPH02288583A (en) | 1990-11-28 |
Family
ID=14509363
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1109403A Pending JPH02288583A (en) | 1989-04-28 | 1989-04-28 | Video signal processing unit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02288583A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0551189A2 (en) * | 1992-01-09 | 1993-07-14 | Matsushita Electric Industrial Co., Ltd. | Video signal correction system |
-
1989
- 1989-04-28 JP JP1109403A patent/JPH02288583A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0551189A2 (en) * | 1992-01-09 | 1993-07-14 | Matsushita Electric Industrial Co., Ltd. | Video signal correction system |
| EP0551189A3 (en) * | 1992-01-09 | 1994-02-02 | Matsushita Electric Ind Co Ltd | |
| US5351141A (en) * | 1992-01-09 | 1994-09-27 | Matsushita Electric Industrial Co., Ltd. | Video signal correction system |
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