JPH02228884A - Noise removing circuit for video camera in low illuminance - Google Patents
Noise removing circuit for video camera in low illuminanceInfo
- Publication number
- JPH02228884A JPH02228884A JP1048537A JP4853789A JPH02228884A JP H02228884 A JPH02228884 A JP H02228884A JP 1048537 A JP1048537 A JP 1048537A JP 4853789 A JP4853789 A JP 4853789A JP H02228884 A JPH02228884 A JP H02228884A
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- aperture
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- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 19
- 238000001514 detection method Methods 0.000 claims abstract description 14
- 238000005286 illumination Methods 0.000 claims description 5
- 230000004044 response Effects 0.000 claims description 5
- 238000005375 photometry Methods 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 230000009467 reduction Effects 0.000 claims description 2
- 230000035945 sensitivity Effects 0.000 abstract description 7
- 230000015556 catabolic process Effects 0.000 abstract 1
- 238000006731 degradation reaction Methods 0.000 abstract 1
- 238000012545 processing Methods 0.000 description 6
- 101100115215 Caenorhabditis elegans cul-2 gene Proteins 0.000 description 5
- 206010047571 Visual impairment Diseases 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
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Abstract
Description
【発明の詳細な説明】
〈産業上の利用分舒〉
本発明は、ビデオカメラにあって被写体が低照度の場合
に発生する雑音の除去回路に関する。DETAILED DESCRIPTION OF THE INVENTION <Industrial Application> The present invention relates to a circuit for removing noise generated in a video camera when a subject is under low illumination.
〈従来の技術とその課題〉
ビデオカメラにて被写体を撮影するに際しては、被写体
が高照度の場合はともかく、低照度の場合には撮像部の
出力のＳ／Ｎが著しく劣化し、好ましい画像が得られな
いという問題がある。<Prior art and its problems> When photographing a subject with a video camera, the S/N ratio of the output of the imaging unit deteriorates significantly when the subject is under low illumination, and it is difficult to obtain a desirable image. The problem is that you can't get it.
つまり、従来では低照度時の雑音除去や感度アップを行
なうべく種々の方策が採られている。That is, conventionally, various measures have been taken to remove noise and increase sensitivity at low illuminance.
第２図はその一例であり、レンズ１、絞り２、撮像素子
であるＣＣＤ３、ゾーン測光のためのアイリスゲー）、
４、ＡＧＣ回路５、信号処理回路６からなる光映像信号
系と、アイリスゲート４による光量検出信号を受けて絞
り２やＡＧＣ回路５を制御する制御部７とを有しており
、被写体の照度すなわちレンズ１への入射光量が十分な
場合にはアイリスゲート４による光量検出信号にてＣＣ
Ｄ ３への入射光量が適正光量となるように制御部７に
て絞り２を制御する。入射光量が減少し絞り２が開放に
なった時以下の光量にあっては、それまで最低増幅度に
なっていたＡＧＣ＠略５の増幅度を制御部７による制御
にて増大させ映像出力を一定としている。Figure 2 shows an example of this, including a lens 1, an aperture 2, an image sensor (CCD 3), and an iris gate for zone photometry.
4. It has an optical video signal system consisting of an AGC circuit 5 and a signal processing circuit 6, and a control section 7 that receives a light amount detection signal from the iris gate 4 and controls the aperture 2 and the AGC circuit 5, and controls the illuminance of the subject. In other words, when the amount of light incident on the lens 1 is sufficient, the light amount detection signal from the iris gate 4 is used to control the CC.
The aperture 2 is controlled by the control unit 7 so that the amount of light incident on the D 3 becomes an appropriate amount of light. When the amount of incident light decreases and the aperture 2 is opened, if the amount of light is less than that, the amplification degree of AGC@approximately 5, which had been the lowest amplification degree, is increased under the control of the control unit 7 and the video output is increased. It is kept constant.
ところが、入射光量の減少によってＣＣＤ３の出力のＳ
／Ｎが劣化し、ＡＧＣ回１１＠５の増幅度を増大させて
も映像出力を一定にしても、それだけでは良好な画像が
得られないという問題がある。However, due to the decrease in the amount of incident light, the output of CCD3
/N deteriorates, and even if the amplification degree of the AGC circuit 11@5 is increased or the video output is kept constant, there is a problem that a good image cannot be obtained by this alone.
第３図は雑音を除去する代り感度アップを企図した回路
であり、信号処理回路６の後段にはＡ／Ｄ変換諾８、メ
モリ９、Ｄ／Ａ変換器１０を有し、ＣＣＤ３及びメモリ
９のタイミング信号がタイミング発生＠１１から出力さ
れるようになっている。かかる回路にて、レンズ１への
入射光量が十分な場合、タイミング発生襞１１からのタ
イミングはフィールド画の読み出し速度である１／６０
秒であるが、入射光量が減少した場合にはタイミング信
号を切９換えてＣＯＤのａｍ時間を通常のｎ倍とし、読
み出し間隔をｎ７６０秒として感度アップをしている。FIG. 3 shows a circuit designed to increase sensitivity instead of removing noise, and has an A/D converter 8, a memory 9, and a D/A converter 10 at the subsequent stage of the signal processing circuit 6, and a CCD 3 and a memory 9. The timing signal is output from the timing generator @11. In such a circuit, when the amount of light incident on the lens 1 is sufficient, the timing from the timing generation fold 11 is 1/60, which is the readout speed of the field image.
However, when the amount of incident light decreases, the timing signal is switched to increase the COD am time to n times the normal value, and the readout interval is set to n760 seconds to increase sensitivity.
この場合、映像出力としては１７６０秒間隔でフィール
ド画を出力する必要があるので、ＣＯＤの読み出し間隔
が１／６０でないｎ／６０秒の場合にはｎ回メモリ９に
記憶した映像信号を出力する必要がある。In this case, it is necessary to output a field image at an interval of 1760 seconds as video output, so if the COD readout interval is n/60 seconds instead of 1/60, the video signal stored in the memory 9 n times is output. There is a need.
しかし、かかる第３図に示す例では、ＣＣＤの蓄積時間
がｎ倍すなわち、２，３．４・・・倍という具合にしか
伸長できないので、減少光量に応じてリニヤに感度アッ
プができず段階的となってしまう。また、ＣＣＤの蓄積
時間すなわちｎが多くなる混同−画像の読み出し回数が
多くなり画像のぶれが大きくなる。However, in the example shown in FIG. 3, the storage time of the CCD can only be extended by n times, that is, 2, 3.4... times, so the sensitivity cannot be increased linearly in accordance with the decreasing amount of light. It becomes a target. Also, the confusion occurs when the CCD storage time, that is, n increases - the number of times the image is read increases, and the image blur increases.
更に、第４図は映像信号の雑音除去回路の一例であって
、Ａ／Ｄ変換器１２．１−にの伝達係数を持つ減衰Ｍ１
３、加丸合せ点１４、フレームメモリ１５、Ｄ／Ａ変換
器１６、及びフレームメモリ１５から加丸合せ点１４に
帰還係数Ｋを持つ帰還減衰器１７を有する。Furthermore, FIG. 4 shows an example of a video signal noise removal circuit, in which an attenuation M1 having a transfer coefficient to the A/D converter 12.1- is shown.
3. It has a frame memory 15, a D/A converter 16, and a feedback attenuator 17 having a feedback coefficient K from the frame memory 15 to the frame alignment point 14.
そして、加え合せ点１４での出力は（１−Ｋ） ＋ （
Ｋ）として常にりを出力するようになっている。Then, the output at the addition point 14 is (1-K) + (
K) is always output.
すなわち、現在のビデオ信号を（１−Ｋ）倍し、フレー
ムメモリ１５に記憶された前（過去）のビデオ信号をに
倍して帰還し加えることにより、両ビデオ信号の共通部
分を残し雑音が除かれることを利用している。そして、
その共通部分を残す程度を係数Ｋにて調節しており、Ｋ
が大きくなるほど雑音は多く除かれ３７Ｎ比が改善され
るというものである。That is, by multiplying the current video signal by (1-K), multiplying the previous (past) video signal stored in the frame memory 15 by , and adding it back, the common part of both video signals is left and the noise is eliminated. They take advantage of being excluded. and,
The degree to which the common parts are left is adjusted by a coefficient K, and K
The larger the value, the more noise is removed and the 37N ratio is improved.
しかし、係数にの値を大きくするに従って、雑音低減効
果は大きくなるが、前の信号が多くを占めることになり
残像も大きくなってしまう。However, as the value of the coefficient increases, the noise reduction effect increases, but the previous signal occupies a large amount, and the afterimage also increases.
そこで、本発明は上述の欠点に鑑み低照度補正に際して
、ＣＣＤによるＳ／Ｎの劣化、ＣＯＤの蓄積時間の伸長
による感度アップ時の段階的現象及びぶれ、更には係数
にの帰還に基づく場合の残像を除いて低照度であっても
高品質の画像を得るようにしたビデオカメラ用雑音除去
回路の提供を目的とする。Therefore, in view of the above-mentioned drawbacks, the present invention addresses the problem of low illuminance correction based on deterioration of S/N due to CCD, gradual phenomenon and blurring when sensitivity is increased due to extension of COD accumulation time, and furthermore, when based on feedback to coefficients. The purpose of the present invention is to provide a noise removal circuit for a video camera, which eliminates afterimages and obtains high-quality images even under low illuminance.
く課題を解決するための手段〉
上述の目的を達成する本発明は、入射光量を調節する絞
り、光電変換部である撮像素子、ゾーン測光を行なうア
イリスゲート、増幅度１１１Ｊｖ！Ｊを行なうＡＧＣ回
路を順に直列に備え、更に上記アイリスゲートによる光
量検出信号を受けて上記絞りを制御すると共にこの絞り
開放時の光量以下の光量にて上記ＡＧＣ回路の増幅度を
増大し得る制御部を備えた露出制御部を有する一方、−
接点が直接に出力端子に接続される切換スイッチの他の
接点から上記出力端子までの間に現在のビデオ信号を１
−Ｋ又はに倍する減衰器、加え合せ点、フレーム又はフ
ィールドメモリを順に直列に備え、上記メモリの出力端
子をＫ又は１−に倍の帰還減衰器を介して上記加え合せ
点に接続し、上記減衰器又は帰還ｗｔ衰器の係数Ｋを上
記制御部にて制御する雑音除去部を有し、上記絞り開放
時の光量以下の光量に当る上記アイリスゲートからの光
量検出信号を受けて上記制御部にて上記切換スイッチを
＃御することを特徴とする。Means for Solving the Problems> The present invention, which achieves the above-mentioned objects, includes an aperture that adjusts the amount of incident light, an image sensor that is a photoelectric conversion section, an iris gate that performs zone photometry, and an amplification of 111 Jv! AGC circuits that perform J are sequentially connected in series, further controlling the aperture in response to a light amount detection signal from the iris gate, and controlling that can increase the amplification degree of the AGC circuit at a light amount less than the light amount when the aperture is opened. -
The current video signal is transmitted between the other contact of the changeover switch whose contact is directly connected to the output terminal and the above output terminal.
- comprising an attenuator that multiplies K or 1-, a summing point, and a frame or field memory in series, the output terminal of the memory being connected to the summing point via a feedback attenuator that multiplies K or 1-; a noise removing section for controlling the coefficient K of the attenuator or the feedback wt attenuator by the control section; and the control section is performed in response to a light amount detection signal from the iris gate that corresponds to a light amount less than the light amount when the aperture is opened. It is characterized in that the changeover switch is controlled by the section.
く作 用〉
低照度の場合アイリスゲートによる光量検出信号にてス
イッチを切換え、ＡＧＣ回路の増幅度を増大させて感度
アップを図ると同様にＣＣＤによるＳ／Ｎ劣化は帰還減
衰器の帰還係数にの調節にて改善しなり、またＡＧＣ回
路の増幅度は変化せず帰還減衰器の帰還係数にのみ調節
するものである。In the case of low illuminance, the switch is switched by the light amount detection signal from the iris gate and the amplification degree of the AGC circuit is increased to increase the sensitivity.Similarly, the S/N deterioration caused by the CCD is affected by the feedback coefficient of the feedback attenuator. However, the amplification degree of the AGC circuit remains unchanged and is adjusted only to the feedback coefficient of the feedback attenuator.
く実 施 例〉
ここで、第１図および第５図を参照して本発明の詳細な
説明する。第１図は全体のブ彎ツク図で、第２図〜第４
図と同一部分には同符号を示す。第１図において、１は
対物レンズ、２は入射光量を調節する絞り、３は光電変
換面を有する撮像素子であるＣＯＤ、４はゾーン測光に
より光量検出信号を制御部７に出力するアイリスゲート
、５はＡＧＣ１ｉ路、６は信号処理回路、７はアイリス
ゲート４からの光量検出信号にて絞妙２もしくはＡＧＣ
回路５を制御する制御部である。Embodiments The present invention will now be described in detail with reference to FIGS. 1 and 5. Figure 1 is an overall book diagram, and Figures 2 to 4
The same parts as those in the figure are given the same reference numerals. In FIG. 1, 1 is an objective lens, 2 is an aperture that adjusts the amount of incident light, 3 is a COD which is an image sensor having a photoelectric conversion surface, 4 is an iris gate that outputs a light amount detection signal to the control unit 7 by zone photometry, 5 is the AGC1i path, 6 is the signal processing circuit, and 7 is the light amount detection signal from the iris gate 4, which is used to control the AGC 2 or AGC.
This is a control section that controls the circuit 5.
以上が露出制御部を構成する。The above constitutes the exposure control section.
信号処理回路６の後段には、切換スイッチ１８が備えら
れている。この切換スイッチ１８の一方の接点は直接出
力端子ＯＵＴに接続されている。他方の接点はＡ／Ｄ変
換器１２、伝達定数１−にの減衰器１３、加え合せ点１
４、フレームメモリ１５ 、Ｄ ／ Ａ 変換器１６
カラなる直列系を順に介して出力端子ＯＵＴに接続され
ている。フレームメモリ１５の出力端は帰還係数にの帰
還減衰器１７を介して加え合せ点１４に接続される。そ
して、この帰還減衰器１７及びｍ表器１３の係数には制
御部７によって制御される。A changeover switch 18 is provided downstream of the signal processing circuit 6. One contact of this changeover switch 18 is directly connected to the output terminal OUT. The other contact point is the A/D converter 12, the attenuator 13 for the transfer constant 1-, and the addition point 1.
4, frame memory 15, D/A converter 16
The output terminals OUT are connected to the output terminal OUT through a series series. The output end of the frame memory 15 is connected to the summing point 14 via a feedback attenuator 17 for feedback coefficients. The coefficients of the feedback attenuator 17 and the m-table 13 are controlled by the controller 7.
以上が雑音除去部である。The above is the noise removal section.
上述の第１図に示す構成において、被写体が高照度であ
ってレンズ１からの入射光量が充分ある場合には、アイ
リスゲート４からの光量検出信号が制御部７に送られて
絞り２が調節されＣＣＤ ３への光量は適切に保たれる
。In the configuration shown in FIG. 1 described above, when the subject is under high illumination and there is a sufficient amount of incident light from the lens 1, a light amount detection signal from the iris gate 4 is sent to the control unit 7, and the aperture 2 is adjusted. The amount of light to the CCD 3 is maintained appropriately.
この場合、ＡＧＣ回路５は制御部７がらの指令により最
低増幅度のままであり減衰器１３゜１７の係数にの制御
も行なわれない。そして更に制御部７が充分な入射光量
による検出信号を受けているため、切換スイッチ１８は
ＯＦＦ側となっており、信号処理回＃Ｉ６の出力がその
まま出力端子ＯＵＴに表われる。かかる絞り制卸状態が
第５図に示す絞りの矢印範囲である。In this case, the AGC circuit 5 remains at the lowest amplification degree according to the command from the control section 7, and the coefficients of the attenuators 13 and 17 are not controlled. Further, since the control section 7 receives a detection signal from a sufficient amount of incident light, the changeover switch 18 is turned off, and the output of the signal processing circuit #I6 appears as it is at the output terminal OUT. This aperture control state is the range of the aperture arrow shown in FIG.
被写体が低照度であってレンズｌからの入射光１が少な
い場合、それに応じて絞り２が制御部７からの指令によ
り開放されるが、更に入射光量が少なくなると絞り２は
開放したまま、アイリスゲート４からの光量検出信号に
基づ（制御部７からの指令によってＡＧＣ回路５の増幅
度が増大される。同時に、制御部７からの指令にて切換
スイッチ１−８がＯＮ側に切換えられ、ＡＧＣ回路にて
増幅されたビデオ信号がＡ／Ｄ変換Ｉ＃１２にてディジ
タル化され、減衰器１３に入力される。When the subject is under low illumination and there is little incident light 1 from the lens l, the aperture 2 is opened according to a command from the control unit 7, but if the amount of incident light decreases further, the iris 2 remains open and the iris is opened. Based on the light amount detection signal from the gate 4 (in response to a command from the control unit 7), the amplification degree of the AGC circuit 5 is increased. At the same time, the selector switch 1-8 is switched to the ON side by a command from the control unit 7. , the video signal amplified by the AGC circuit is digitized by the A/D converter I#12 and input to the attenuator 13.
この減衰＠ｓ１３では、この「現在」のビデオ信号が（
１−Ｋ）倍され（Ｋは１より小さく例えば捧・１７４等
の値をとるため）このビデオ信号は減衰される。一方、
フレームメモリ１５にすでに記憶された前（過去）のビ
デオ信号は、帰還ｗｔ衰器１７にてに倍されて、前述し
た減衰器１３を経由して（１−Ｋ）倍された「現在」の
ビデオ信号と加え合せ点１４にて加算される。この結果
、加え合せ点１４からの出力信号は（１−Ｋ）＋にすな
わち１となり、減衰前のビデオ信号と同じになるが、そ
の信号の内容は「現在」のビデオ信号と今までの過去の
ビデオ信号とが加算され、しかも１フレームのビデオ信
号中に存在する不規則な雑音が除かれる傾向となる。In this attenuation @s13, this "current" video signal is (
1-K) (because K is less than 1 and has a value such as 174), this video signal is attenuated. on the other hand,
The previous (past) video signal already stored in the frame memory 15 is multiplied by the feedback wt attenuator 17, and passed through the above-mentioned attenuator 13 to the "current" signal multiplied by (1-K). It is added to the video signal at a summing point 14. As a result, the output signal from the summing point 14 is (1-K)+, that is, 1, which is the same as the video signal before attenuation, but the content of the signal is the "current" video signal and the past past video signal. video signals of one frame are added together, and irregular noise present in one frame of video signals tends to be removed.
したがって、低照度時増幅度を増大させて映像出力を一
定としても、なお残存するＳ／Ｎの劣化は、この減衰器
１３及び帰還減衰器１７による雑音除去部にて改善され
ることになる。Therefore, even if the video output is kept constant by increasing the amplification degree during low illuminance, the remaining S/N deterioration will be improved by the noise removal section formed by the attenuator 13 and the feedback attenuator 17.
この場合、雑音除去部のＳ／Ｎの改善は増幅度を増大さ
せた雑音を含むビデオ信号に対して行なわれるため、ビ
デオ信号自体も増幅されていることから雑音除去の程度
も少なくて済み、結局残像が問題になる程係数Ｋを大き
くする必要がない。この係数にの変化は制御部７からの
制卸信号にて行なわれる。In this case, since the S/N improvement of the noise removal section is performed on a video signal containing noise with an increased degree of amplification, since the video signal itself has also been amplified, the degree of noise removal can be reduced. After all, it is not necessary to make the coefficient K so large that the afterimage becomes a problem. This coefficient is changed by a control signal from the control section 7.
このＡＧＣ回＃Ｉ５の増幅度調節及び雑音除去部による
雑音除去は、第５図に示すＡＧＣ。The amplification degree adjustment and noise removal by the noise removal section of this AGC circuit #I5 are performed by the AGC shown in FIG.
雑音除去の矢印ｌｉＸ囲にて行なわれる。第１図、第５
図では、低照度時にはＡＧＣ回路５の増幅度を大きくす
ると共に雑音除去部での係数Ｋを変化させろ機能につき
説明したが、低照度時でのＡＧＣ＠路５の増幅度は最低
ゲインのままで帰還係数にのみを被写体照度に合わせて
変化させることもできる。すなわち、制御部７によるＡ
ＧＣ回路の増幅制御は行なわず、アイリスゲート４によ
る絞り開放に相応する光量検出信号にて制御部７による
切換スイッチ１８のみのＯＮ制御と同時に帰還係数にの
変化を開始させることもできる。This is performed around the noise removal arrow liX. Figures 1 and 5
In the figure, we have explained the function of increasing the amplification degree of the AGC circuit 5 and changing the coefficient K in the noise removal section at low illuminance, but the amplification degree of the AGC circuit 5 remains at the lowest gain at low illuminance. It is also possible to change only the feedback coefficient in accordance with the illuminance of the subject. That is, A by the control section 7
It is also possible to not perform amplification control of the GC circuit, but to start changing the feedback coefficient simultaneously with ON control of only the changeover switch 18 by the control section 7 using a light amount detection signal corresponding to opening of the aperture by the iris gate 4.
なお、第１図では雑音除去部は信号処理口＃６の後段に
挿入したが、ＣＣＤ３の後段であればその配置は問題な
い。ただ、アイリスゲート４の前段では８ピツトの量子
化ノイズが生じることもあるが、これとて致命的な問題
とはならない。In FIG. 1, the noise removal section is inserted after the signal processing port #6, but there is no problem with its placement as long as it is after the CCD 3. However, although 8-pit quantization noise may occur at the stage before the iris gate 4, this is not a fatal problem.
また、メモリとしてはフレームメモリ１５を用いている
が、フィールドメモリを用いて、フィールド間の相同が
あれば差支えない。この場合、ラスターが同一位置にな
いので、全直間解像度が劣化するが、その代り残像が緩
和される。Furthermore, although the frame memory 15 is used as the memory, a field memory may be used as long as there is homology between the fields. In this case, since the rasters are not in the same position, the total direct resolution is degraded, but in return, the afterimage is alleviated.
〈発明の効果〉
以上説明したように本発明によれば、従来の欠点なく低
照度時にもＳ／Ｎを抑えて良好な撮影が可能となっｔコ
。<Effects of the Invention> As explained above, according to the present invention, it is possible to suppress the S/N and take good pictures even in low illuminance without the drawbacks of the conventional method.
第１図は本発明の一実施例のブロック図、第２図ないし
第４図は三つの従来例のブロック図、第５図は本発明の
一実施例の説明に供する動作範囲のグラフである。
図 中、
２は絞り、
４はアイリスゲート、
５はＡＧＣ回路、
７は制御部、
１３は減衰器、
１４は加え合せ点、
１５はフレームメモリ、
１７は帰還減衰器、
１８は切換スイッチである。FIG. 1 is a block diagram of an embodiment of the present invention, FIGS. 2 to 4 are block diagrams of three conventional examples, and FIG. 5 is a graph of the operating range used to explain the embodiment of the present invention. . In the figure, 2 is an aperture, 4 is an iris gate, 5 is an AGC circuit, 7 is a control unit, 13 is an attenuator, 14 is a summing point, 15 is a frame memory, 17 is a feedback attenuator, and 18 is a changeover switch. .
Claims (1)
ゾーン測光を行なうアイリスゲート、増幅度制御を行な
うＡＧＣ回路を順に直列に備え、更に上記アイリスゲー
トによる光量検出信号を受けて上記絞りを制御すると共
にこの絞り開放時の光量以下の光量にて上記ＡＧＣ回路
の増幅度を増大し得る制御部を備えた露出制御部を有す
る一方、 一接点が直接に出力端子に接続される切換スイッチの他
の接点から上記出力端子までの間に現在のビデオ信号を
１−Ｋ又はＫ倍する減衰器、加え合せ点、フレーム又は
フィールドメモリを順に直列に備え、上記メモリの出力
端子をＫ又は１−Ｋ倍の帰還減衰器を介して上記加え合
せ点に接続し、上記減衰器又は帰還減衰器の係数Ｋを上
記制御部にて制御する雑音除去部を有し、上記絞り開放
時の光量以下の光量に当る上記アイリスゲートからの光
量検出信号を受けて上記制御部にて上記切換スイッチを
制御する、低照度時でのビデオカメラ用雑音除去回路。[Claims] An aperture that adjusts the amount of incident light, an image sensor that is a photoelectric conversion unit,
An iris gate that performs zone photometry and an AGC circuit that performs amplification control are sequentially connected in series, and the aperture is controlled in response to a light amount detection signal from the iris gate, and the AGC circuit controls the aperture when the amount of light is less than the amount of light when the aperture is fully open. It has an exposure control section with a control section that can increase the amplification of the circuit, while the current video signal is transmitted between the other contact of the changeover switch, one contact of which is directly connected to the output terminal, and the said output terminal. A 1-K or K times attenuator, a summing point, and a frame or field memory are provided in series, and the output terminal of the memory is connected to the summing point via a K or 1-K times feedback attenuator. , further comprising a noise removing section for controlling a coefficient K of the attenuator or feedback attenuator by the control section, and controlling the above in response to a light amount detection signal from the iris gate that corresponds to a light amount less than the light amount when the aperture is open. A noise reduction circuit for video cameras in low illumination, which controls the above-mentioned changeover switch in the section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1048537A JPH02228884A (en) | 1989-03-02 | 1989-03-02 | Noise removing circuit for video camera in low illuminance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1048537A JPH02228884A (en) | 1989-03-02 | 1989-03-02 | Noise removing circuit for video camera in low illuminance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02228884A true JPH02228884A (en) | 1990-09-11 |
Family
ID=12806114
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1048537A Pending JPH02228884A (en) | 1989-03-02 | 1989-03-02 | Noise removing circuit for video camera in low illuminance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02228884A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06164992A (en) * | 1990-08-30 | 1994-06-10 | Samsung Electron Co Ltd | Video-signal processing device and selective noise-attenuation device in said device |
| KR20020023523A (en) * | 2000-09-22 | 2002-03-29 | 박규영 | A Camera for revising illumination |
| KR100444329B1 (en) * | 2002-02-16 | 2004-08-16 | 주식회사 성진씨앤씨 | Digital video processing device eliminating the noise generated under insufficient illulmination |
-
1989
- 1989-03-02 JP JP1048537A patent/JPH02228884A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06164992A (en) * | 1990-08-30 | 1994-06-10 | Samsung Electron Co Ltd | Video-signal processing device and selective noise-attenuation device in said device |
| KR20020023523A (en) * | 2000-09-22 | 2002-03-29 | 박규영 | A Camera for revising illumination |
| KR100444329B1 (en) * | 2002-02-16 | 2004-08-16 | 주식회사 성진씨앤씨 | Digital video processing device eliminating the noise generated under insufficient illulmination |
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