JP3729522B2 - Imaging system using CCD - Google Patents

Description

例えば上記モデルの１画面当たりの撮像時間Ｆｎは、（２）式にｍ＝８、ｎ＝４を代入すれば求まることになる。
【００４０】
なお、撮像面Ｉａにおける入射光量が全体的に多くて、棄却用の信号電荷が水平転送路７内で飽和する事態が想定される場合は、廃棄ＶΦの回数を増やすように設定してもよい。
【００４１】
図６に示す不一致モードの縦モード１は、その動作及び撮像時間が通常モードと同様となり、高速モードとしては動作しない。また、同図に示す不一致モードの縦横モード１については、その動作原理及び撮像時間が上記横モード１と殆ど同じである。
【００４２】
図８（ａ）〜（ｄ）は、一致モードの内の横モード２の動作原理及びその撮像時間を説明するものである。この横モード２に対応した高速パルスパターンＳ２は、上記横モード１と比べると、上記連続ＶΦ及び廃棄ＰΦに加え、省略ＶΦ及び省略ＰΦを含む点が異なっている。
【００４３】
例えば、上記と同様のモデルで考えた場合、図８（ａ）に示す横モード２から成る対象領域Ａ１では、同図（ｂ）に示す如く、最初（下側）の非対象領域Ａ２ａの横画素群Ｌ１及びＬ２を連続ＶΦ及び廃棄ＶΦによりまとめて棄却用に読取る。続いて、対象領域Ａ１の横画素群Ｌ３…Ｌ６を通常パルスパターンで読取った後に、最後（上側）の非対象領域Ａ２ｂの横画素群Ｌ７及びＬ８を省略ＶΦ及び省略ＶΦにより、同図（ｃ）に示す如く、最初の非対象領域Ａ２ａ内の位置でストップさせた状態で１画面の読取りを終了させる。つまり、次画面読取り時には、連続ＶΦ及び廃棄ＶΦにより、前画面の横画素群Ｌ７及びＬ８の信号電荷を次画面の横画素群Ｌ１及びＬ２の信号電荷に加算した状態でまとめて棄却用に読取ることができる。
【００４４】
従って、上記モデルを一般化して、上記と同じく走査線数ｍ及びｎを定義すると、この横モード２における１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００４５】
【数３】

例えば上記モデルの１画面当たりの撮像時間Ｆｎは、（３）式にｍ＝８、ｎ＝４を代入すれば求まることになる。
【００４６】
図９は、一致モードの内の縦モード２の動作原理及びその撮像時間を説明するものである。この横モード２に対応した高速パルスパターンＳ２は、上記横モード１、２に共通の連続ＶΦ等の所要モードではなくて部分ＰΦだけを含んでおり、そのタイミングは対象領域Ａ１の縦画素群数で決定される。
【００４７】
例えば、上記と同様のモデルで考えた場合、図９に示す縦モード２から成る対象領域Ａ１では、全ての横画素群を対象とする部分ＰΦにより、同図に示すタイミングで対象領域Ａ１の縦画素群までの信号電荷を読取った後に、第３転送ａ３を止めて第２転送ａ２が実行される。これにより、最後（右側）の非対象領域Ａａ１の横画素群の信号電荷を、次の最初（左側）の非対象領域Ａ２ａの横画素群の信号電荷に重ねて棄却用として読取ることができる。
【００４８】
従って、上記モデルを一般化して、上記と同様の走査線数ｍに加え、撮像面Ｉａ内の縦画素群数で定まる走査線長Ｓ、及び対象領域Ａ１内の縦画素群数で定まる走査線の部分長Ｑを定義すると、この縦モード２における１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００４９】
【数４】

例えば上記モデルの１画面当たりの撮像時間Ｆｎは、（４）式にｍ＝８、（Ｓ＋Ｑ）／（２・Ｓ）＝２／３を代入すれば求まることになる。
【００５０】
なお、一致モードの内の縦横モード２は、例えば図１０に示すように、上記横モード２及び縦モード２の組み合わせにより任意に設定できる。
【００５１】
ここで、実施例に戻り、駆動制御部７のＣＰＵ１０の処理を中心にして、全体動作を図１１に基づき説明する。ここでは、上記高速モードの内の一致モードが設定されているとする。
【００５２】
まず、オペレータが入力デバイス１４を操作して高速モードである対象領域の位置データが指示されたとする。この指示を受けて、ＣＰＵ１０は、図１１に示す処理を実行する。まず、ステップＳ１にて指定対象領域Ａ１を入力すると、ステップＳ２にてその対象領域Ａ１が横方向、縦方向、又は縦横方向であるか否かを判断する。例えば、縦方向であると判断した場合、ステップＳ３ａにてその縦方向の位置を入力し、ステップＳ４ａにて縦モード２を決定する。また、横方向又は縦横方向の場合も、上記ステップＳ３ａ及びＳ４ａと同様の処理により、横モード２又は縦横モード２を決定する。
【００５３】
次いで、ステップＳ５にて上記決定された高速モードに応じた高速パルスパターンＳ２が決定され、カウンタＣ１…Ｃ３の夫々に個別に出力される。従って、カウンタＣ１…Ｃ３の夫々が高速パルスパターンＳ２に基づいた基準クロックの計数値をカウントすることにより、パルス発生器Ｐ１…Ｐ３の夫々から駆動パルスＲΦ、ＶΦ、ＰΦがＣＣＤ１に出力される。
【００５４】
以上により、本実施例では、ＣＣＤの撮像面に対象領域を設定し、その対象領域の位置情報に応じて信号電荷の各転送時期を制御して読取るように構成したため、従来の撮像速度よりも高速化を実現でき、これにより、スローモーション画像等の有効活用を図ることができる。また、一般のＣＣＤに容易に適用できるので装置全体を安価に構築できる。さらに、高速モードとして一致モードを採用した場合、画像の中心とレンズの中心とを常に一致させることができるので、レンズ解像力の比較的優れた中心位置にスローモション映像を表示させることができ、オペレータの操作性が向上するようになる。
【００５５】
なお、上記実施例では、横モード時に連続ＶΦ及び廃棄ＶΦにより、水平転送路に不要画素信号を加算させた状態で掃き捨てるように構成したが、本発明は必ずしもこれに限定されるものではない。例えば、ドレイン等に掃き捨てる機能を備えたＣＣＤを用いた場合には、水平転送路からドレイン等に掃き捨てるように適用してもよい。この場合、廃棄ＶΦ時の水平転送（第３転送）を省略でき、その省略分、より高速化を図ることができる。
【００５６】
（第２実施例）
以下、本発明の第２実施例を図１２〜図２１に基づき説明する。この実施例は、上記第１実施例の高速モード用の構成を一部変更して実施したものである。ここで、上記第１実施例の同一又は同等の構成要素については、同一又は同等の符号を付してその説明を簡略又は省略する。
【００５７】
図１２に示すＣＣＤを用いた撮像システムは、ＣＣＤ１と光学系ＯＰとの間に上記高速モード時に作動する、光透過体である遮光部１４が配置されている。この遮光部１４は、例えば少なくともＣＣＤ１の撮像面Ｉａと同じ大きさの開口を備えた開閉自在の遮光用のマスク１５と、そのマスク１５の略四角形状の開口状態を、撮像面Ｉａ内の縦及び横方向に沿って開閉させるステップモータ等を含むマスク開閉機構１６とを備えている。このマスク開閉機構１６は、駆動制御部７からの高速モード用の各対象領域Ａ１に関する位置データＳ４を入力して、マスク１５の開閉状態を制御するようになっている。
【００５８】
上記構成により、遮光部１４は、対物光学系ＯＰからの光をマスク１５の開口を介してＣＣＤ１の撮像面Ｉａ内における対象領域Ａ１のみに入射させるようになっている。
【００５９】
ここで、マスク１５を使用した高速モード（以下、「マスク高速モード」と呼ぶ）の作動原理及び撮像時間を説明する。
【００６０】
まず、マスク高速モードの対象とすべき撮像面Ｉａ内の対象領域Ａ１には、上記高速モードと同様の「一致モード」及び「不一致モード」の夫々における、「横モード」、「縦モード」、及び「縦横モード」があり、これに加え、「高速縦モード」（後述）が新たに設定されている（図１３参照）。
【００６１】
また、上記各マスク高速モードの夫々に対応した高速パルスパターンＳ３には、図１３に示す如く、上記５つの所要パターンの内の「廃棄ＰΦ」が除かれている。この理由は、マスク１４を使用した場合、光が遮蔽されて非対象領域Ａ２に入射しないため、例えば回折光の影響等による暗電流発生事態も想定されるものの、実用上、非対象領域Ａ２内の画素の信号電荷を０と仮定してよいからである。つまり、非対象領域Ａ２の信号電荷を０とすると、この位置に対象領域Ａ１の信号電荷を重ねるパターンを想定してもよいので、廃棄用として更に読取る必要がない。
【００６２】
以下、上記マスク高速モード毎にその動作原理及び撮像時間を説明する。
【００６３】
図１４（ａ）及び（ｂ）は、不一致モードの内のマスク横モード１の動作原理及びその撮像時間を説明するものである。このマスク横モード１に対応した高速パルスパターンＳ３は、上記横モード２と比べると、連続ＶΦ及び廃棄ＶΦがなく省略ＶΦ及び省略ＰΦのみを含むもので、そのタイミングが対象領域Ａ１の横画素群Ｌ１…Ｌｍの走査線数ｍで決定されるようになっている。例えば、上記と同様のモデルで考えた場合、図１４（ａ）に示す横モード１から成る対象領域Ａ１では、同図（ｂ）に示すタイミングで、最初の対象領域Ａ１の横画素群Ｌ１…Ｌ４だけの信号電荷を通常モードと同じパルスパターンで読取り、続く非対象領域Ａ２の横画素群Ｌ５…Ｌ８を省略ＶΦ及び省略ＶΦにより、対象領域Ａ１内の位置にストップさせた状態で１画面の読取りを終了させる。横画素群Ｌ５…Ｌ８の信号電荷は０とみなせるので、この上に次画面における横画素群Ｌ１…Ｌ４の信号電荷を重ねても、実質的に殆ど影響がない。つまり、上記１画面読取り終了後に続けて次画面読取りを実行することができる。
【００６４】
従って、上記モデルを一般化して、上記と同じく対象領域Ａ１内の走査線数ｎを定義すると１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００６５】
【数５】
Ｆｎ＝Ｒｔ＋ｎ×（Ｖｔ＋Ｐｔ） ……（５ａ）
例えば上記モデルの１画面当たりの撮像時間Ｆｎは、（２）式にｎ＝４を代入すれば求まることになる。また、一般にＲｔ＜＜ｎ×（Ｖｔ＋Ｐｔ）の関係となるので、このＲｔを０と仮定すると、このマスク横モード１の撮像時間Ｆｎと通常モードの撮像時間Ｆｍとの撮像時間比Ｒは次式となる。
【００６６】
【数６】

【００６７】
図１５（ａ）及び（ｂ）は、不一致モードの内のマスク縦モード１の動作原理及びその撮像時間を説明するものである。このマスク縦モード１に対応した高速パルスパターンＳ３は、上記縦モード２と同様に部分ＰΦのみを含んでおり、そのタイミングは対象領域Ａ１の縦画素群数で決定される。例えば、上記と同様のモデルで考えた場合、図１５（ａ）に示す縦モード２から成る対象領域Ａ１では、全ての横画素群を対象とする部分ＰΦにより、同図（ｂ）に示すタイミングで、対象領域Ａ１の縦画素群の信号電荷を読取った後に、第３転送ａ３を止めて第２転送ａ２が実行される。つまり、非対象領域Ａ２の横画素群のＯの信号電荷の上に、次の対象領域Ａ１のの横画素群の信号電荷を重ねても実質的に殆ど影響がない。
【００６８】
従って、上記モデルを一般化して、上記と同じ走査線数ｍ、走査線長Ｓ、及び部分長Ｑを定義すると、１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００６９】
【数７】

例えば上記モデルの１画面当たりの撮像時間Ｆｎは、（６ａ）式にｍ＝８、（Ｑ／Ｓ）＝１／２を代入すれば求まることになる。ここで、一般にＲｔ＜＜ｎ×（Ｖｔ＋Ｐｔ）、Ｖｔ＜＜Ｐｔの関係となるので、このＲｔ、ＰｔをＯとみなすと、このマスク縦モード１の撮像時間Ｆｎと通常モードの撮像時間Ｆｍ（（１）式参照）との撮像時間比Ｒは次式となる。
【００７０】
【数８】

【００７１】
図１６（ａ）及ぶ（ｂ）は、不一致モードの内のマスク縦横モード１の動作原理及びその撮像時間を説明するものである。このマスク縦横モード１に対応した高速パルスパターンＳ３は、上記マスク横及び縦モード１の夫々のパターンを組み合わせたものある。例えば、上記と同様のモデルで考えた場合、図１６（ａ）に示すマスク縦横モード２から成る対象領域Ａ１では、同図（ｂ）に示すタイミングで、対象領域Ａ１の横画素群Ｌ１…Ｌ４を対象とする部分ＰΦと、非対象領域Ａ２の一部である横画素群Ｌ５…Ｌ８を対象とする省略ＶΦ及びＰΦとを設定すればよい。
【００７２】
従って、上記モデルを一般化して、上記と同じ走査線ｍ、ｎ、走査線長Ｓ、及び部分長Ｑを定義すると、このマスク縦横モード２の１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００７３】
【数９】

例えば上記モデルの１画面当たりの撮像時間Ｆｎは、（７ａ）式にｎ＝８、（Ｑ／Ｓ）＝１／２を代入すれば求まることになる。ここで、一般にＲｔ＜＜ｎ×（Ｖｔ＋Ｐｔ）、Ｖｔ＜＜Ｐｔの関係となるので、このＲｔ、Ｐｔを０とみなすと、このマスク縦横モード１の撮像時間Ｆｎと通常モードの撮像時間Ｆｍ（（１）式参照）との撮像時間比Ｒは次式となる。
【００７４】
【数１０】

【００７５】
図１７（ａ）及び（ｂ）は、一致モードの内のマスク横モード２の動作原理及びその撮像時間を説明するものである。このマスク横モード２に対応した高速パルスパターンＳ３は、前述の横モード２と比べると、廃棄ＰΦを除外している点が異なる。例えば、上記と同様のモデルで考えた場合、図１７（ａ）に示す横モード２から成る対象領域Ａ１では、同図（ｂ）に示すタイミングで、最初の非対象領域Ａ２ａの横画素群Ｌ１及びＬ２を連続ＶΦにより水平転送路に蓄積（信号電荷は０）させた状態で、対象領域Ａ１の横画素群Ｌ３…Ｌ６を通常パルスパターンで読取る。続いて、上側の非対象領域Ａ２ｂの横画素群Ｌ７及びＬ８を省略ＶΦ及び省略ＶΦにより、下側の非対象領域Ａ２ａ内の位置でストップさせた状態で１画面の読取りを終了させる。つまり、次画面読取り時には連続ＶΦにより、前画面の横画素群Ｌ７及びＬ８を次画面の横画素群Ｌ１及びＬ２と共に、水平転送路に蓄積（信号電荷は０）させるだけでよい。
【００７６】
従って、上記モデルを一般化して、上記と同じく走査線数ｍ及びｎを定義すると１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００７７】
【数１１】

例えば上記モデルの１画面当たりの撮像時間Ｆｎは、（３）式にｍ＝８、ｎ＝４を代入すれば求まることになる。
【００７８】
図１８は、一致モードの内のマスク縦モード２の動作原理及びその撮像時間を説明するものである。このマスク縦モード２に対応した高速パルスパターンＳ３は部分ＰΦだけを含んでおり、そのタイミングは対象領域Ａ１の縦画素群数で決定される。例えば、上記と同様のモデルで考えた場合、図１８に示すマスク縦モード２から成る対象領域Ａ１では、全ての横画素群を対象とする部分ＰΦにより、同図（ｂ）に示すタイミングで対象領域Ａ１の縦画素群までの信号電荷を読取った後に、第３転送ａ３を止めて第２転送ａ２が実行される。つまり、右側の非対象領域Ａ２ｂの横画素群の信号電荷（殆ど０）を次の第３転送ａ３時に左側の非対象領域Ａ２ａの横画素群の信号電荷（殆ど０）と共に読取ればよい。
【００７９】
従って、上記モデルを一般化して、上記と同様の走査線数ｍ、走査線長Ｓ、及び部分長Ｑを定義すると、１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００８０】
【数１２】

【００８１】
図１９は、一致モードの内のマスク高速縦モードの動作原理及びその撮像時間を説明するものである。このマスク高速縦モードは、上記マスク縦モード２の高速化を図るもので、対応する高速パルスパターンＳ３の部分ＰΦの動作期間を短縮させたものである。例えば、上記と同様のモデルを考えた場合、図１９に示すマスク高速縦モードから対象領域Ａ１では、全ての横画素群を対象とする部分ＰΦにより、同図に示すタイミングで、対象領域Ａ１の横画素群の読取りの開始前又は開始途中で第２転送ａ２を実行させている。つまり、左側及び右側の夫々の非対象領域Ａ２ａ及びＡ２ｂの信号電荷を０とみなせば、この非対象領域Ａ２ａ及びＡ２ｂに対象領域Ａ１の信号電荷を相互に重畳させても実質的に影響がないためである。
【００８２】
従って、上記モデルを一般化して、上記と同様の走査線数ｍ、走査線長Ｓ、及び部分長Ｑを定義すると、１画面当たりの撮像時間Ｆｎは理論上、次の算出式で求まる。
【００８３】
【数１３】

【００８４】
なお、図２０に示す一致モードの内のマスク縦横モード２は、マスク横モード２とマスク縦モード２（高速縦モードも含む）とを任意に組み合わせて設定されるようになっている。また、縦横モードに関しては、例えば図２１に示すように、上記第１実施例に係る横及び縦モード２と、本実施例に係るマスク横及び縦モード２（高速縦モードも含む）とを相互に組み合わせた複合縦横モード１、２を設定することも可能である。
【００８５】
以上、本実施例では、上記第１実施例と同様の動作に加え、遮光部１４のマスク１５の開口形状が駆動制御部のＣＰＵ１０からの位置データＳ４により任意に変更されるようになっている。その他の動作は上記マスク高速モードに沿って実行される。なお、遮光部１４は、上記マスク及びマスク開閉機構の構成に限定されるものではなく、例えば光透過型の液晶ディスプレイを使って、対象領域Ａ１に相当する開口形状を表示させ、その表示された開口のみに光を透過させる構造を採用してもよい。また、手動でマスクを開閉させる構成であってもよい。
【００８６】
以上、第１及び第２実施例に係る高速モードの内の代表的なものについて、その撮像時間Ｆｎの算出式に、撮像面Ｉａの約１／２を対象領域とする実際的な数値（Ｒｔ＝１、Ｖｔ＝１、Ｐｔ＝５００、ｍ＝５００、ｎ＝２５０、Ｓ＝５００、Ｑ＝２５０）を代入して計算すると、以下の結果を得た。
【００８７】
まず、第１実施例（マスクなし）に係る不一致モードの内の横モード１（（２）式）、一致モードの内の横モード２（（３）式）、及び縦モード２（（４）式）の夫々の撮像時間は、Ｆｎ＝１２６Ｋ（Ｋ＝１、０００）、１２６Ｋ、及び１８８Ｋであった。また、第２実施例に係る一致モードの内のマスク横モード２（（８）式）、マスク縦モード２（（９）式）、及びマスク縦高速モード（（１０）式）の夫々の撮像時間は、Ｆｎ＝１２５Ｋ、１８８Ｋ、及び１２５Ｋであった。
【００８８】
つまり、横モードの撮像時間については、いずれの高速モードに関しても殆ど大差がなく、また、縦モードの撮像時間については、マスク高速縦モードが最も高速であった。因みに、通常モード（（１）式）の撮像時間はＦｍ＝２５０Ｋであった。従って、理論上、例えば撮像面Ｉａの約１／２を高速モードの対象領域Ａ１とする場合は、通常モードと比べ、横モード及びマスク高速縦モードで１／２程、又縦モードで３／４程の撮像時間の短縮化、即ち高速化を実現できることが確認できた。
【００８９】
なお、上記第１及び第２実施例に係る駆動制御部の構成は必ずしも上記に限定されるものではない。例えば、図２２は駆動制御部の動作原理の基本概念の流れを説明するもので、同図に示す如く、ステップ１００〜１０６の動作を実現できるものであればよい。すなわち、ステップ１００、１０１、１０３（及び１０４）のカウンタに代表させる動作と、ステップ１０２に代表させるマイクロコンピュータ等の処理とを実現可能な回路構成であればよい。
【００９０】
従って、駆動制御部はカウンタに対して外部からカウントすべき計数値をセットさせる構成でもよく、或いは上記高速モードの夫々に対応する複数のカウンタ回路を設けた構成であってもよい。要するに、駆動制御部は上記高速モードの動作原理に必要な駆動信号を生成できる回路であればよく、例えば上記第１及び第２実施例で使用したＣＰＵを要部構成として使用しないで、フリップフロップ等を要部とするデジタル回路で構成することも可能である。
【００９１】
【発明の効果】
以上説明したように、請求項１〜８に記載の発明に係るＣＣＤを用いた撮像システムは、ＣＣＤ撮像面内の一部に上記水平方向又は垂直方向の少なくとも一方に沿う仮想切分け線により区分けされた対象領域の上記撮像面における位置を示すデータであって当該対象領域の中心位置及び当該仮想区分け線の区分け方向を含む位置データに基づいて、上記対象領域に応じた上記垂直転送及び水平転送の夫々の動作時期を判断する時期判断手段と、この時期判断手段により上記夫々の動作時期になったと判断されている間、上記対象領域の撮像素子群の画素信号を上記一定間隔よりも短い撮像間隔で連続して読み取るように垂直転送及び水平転送を制御する画像読取り手段と、を備えたため、ＣＣＤの読み取り画素数を減らして１画面当たりの撮像時間を短縮し、撮像速度の高速化を図ることができる。
【図面の簡単な説明】
【図１】第１及び第２実施例に係るＣＣＤを用いた撮像システムの全体構成を示す概略ブロック図。
【図２】ＣＣＤの撮像面の概略説明図。
【図３】駆動制御部の要部構成を示す概略ブロック図。
【図４】通常撮像時のＣＣＤの動作原理を説明するモデルの概要図。
【図５】図４に示すモデルの各部の動作を示すタイミングチャート。
【図６】第１実施例の高速モードの種類とパルスパターンとの対応図。
【図７】不一致モードの内の横モードの動作原理を説明するモデルで、（ａ）は概要図、（ｂ）は概略タイミングチャート。
【図８】一致モードの内の横モードの動作原理を説明するモデルで、（ａ）〜（ｃ）は概要図、（ｄ）は概略タイミングチャート。
【図９】一致モードの内の縦モードの動作原理を説明するモデルの概要図。
【図１０】一致モードの内の縦横モードを説明するモデルの概要図。
【図１１】駆動制御部のＣＰＵの処理を示す概略フローチャート。
【図１２】第２実施例に係るＣＣＤを用いた撮像システムの要部構成を示す概略ブロック図。
【図１３】第２実施例のマスク高速モードの種類とパルスパターンとの対応図。
【図１４】不一致モードの内のマスク横モードの動作原理を説明するモデルで、（ａ）は概要図、（ｂ）は概略タイミングチャート。
【図１５】不一致モードの内のマスク縦モードの動作原理を説明するモデルで、（ａ）は概要図、（ｂ）は概略タイミングチャート。
【図１６】不一致モードの内のマスク縦横モードの動作原理を説明するモデルで、（ａ）は概要図、（ｂ）は概略タイミングチャート。
【図１７】一致モードの内のマスク横モードの動作原理を説明するモデルで、（ａ）は概要図、（ｂ）は概略タイミングチャート。
【図１８】一致モードの内のマスク縦モードの動作原理を説明するモデルで、（ａ）は概要図、（ｂ）は概略タイミングチャート。
【図１９】一致モードの内のマスク高速縦モードの動作原理を説明するモデルの概要図。
【図２０】一致モードの内のマスク縦横モードを説明するモデルの概要図。
【図２１】複合モードの組み合わせ対応図。
【図２２】第１及び第２実施例の駆動制御部の動作原理の概念の流れを説明する概略フローチャート。
【符号の説明】
１ ＣＣＤ
２ デバイス部
３ 画像処理部
４ 画像表示部
Ｉａ 撮像面
５ 撮像素子
６ 垂直転送路
７ 水平転送路
８ 駆動制御部
１０ ＣＰＵ[0001]
[Industrial application fields]
The present invention relates to an imaging system using a CCD (solid-state imaging device), and more particularly to an imaging system using a CCD that realizes an increase in imaging speed required per screen.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an imaging system such as a video camera drives an area sensor such as a CCD or a MOS sensor, and sequentially obtains image data for each screen (frame) of a subject at regular intervals. The time-series change state of the image data can be observed as a video reproducing the movement of the subject.
[0003]
Using this imaging system, when a moving image captured at a speed exceeding a predetermined standard speed (for example, 30 screens / second in the “NTSC” system) is reproduced according to the standard speed, a slow motion video can be observed. That is, when an image captured at n times the standard speed is played back at the standard speed, the movement of the subject can be observed with a slowness of 1 / n times. This slow motion video is, for example, as one of image analysis means such as dynamic analysis in the field of sports (such as motion analysis of players and determination of victory or defeat), academic research field, or industrial production field. It is more effective.
[0004]
Therefore, in order to acquire the slow motion video, some imaging systems apply high-speed imaging means that images at a speed exceeding the standard speed. As this high-speed imaging means, a method of increasing the sensor response speed by generally increasing the clock frequency of the area sensor is well known. However, since there is a physical limitation due to the sensor reaction speed, as a method for achieving a higher speed than the limitation, means for reducing the number of read pixels per screen using a MOS sensor (for example, a special feature) Kaihei 5-167937 and JP-A-5-236364) have been proposed.
[0005]
For example, assuming that the predetermined standard of the area sensor is the number of pixels = 640 (horizontal) × 480 (vertical) (pieces) and the imaging speed = 30 (screen / second), the number of read pixels is ¼ times (320 × 240). In theory, the imaging speed can be increased to four times the predetermined standard (120 (screen / second)).
[0006]
[Problems to be solved by the invention]
However, since the proposed MOS type sensor is generally low in sensitivity, it cannot fully satisfy the demand from the field of image utilization that it is desired to observe slow motion video with a clearer image quality. It was.
[0007]
On the other hand, compared with the MOS type sensor, the CCD is generally popular and has an advantage of higher sensitivity. However, the pixel reading method of the CCD is different from the pixel reading method of the MOS type sensor that employs the so-called XY address type, and adopts a so-called interline type that sequentially reads out each pixel along the scanning line. In order to apply the means for reducing the number of read pixels to the CCD, it is necessary to fundamentally review the operation principle of the interline type, which is complicated and disadvantageous in terms of cost.
[0008]
The present invention has been made in consideration of the above-described problems of the prior art, and uses a CCD that can easily and relatively inexpensively increase the imaging speed per screen by taking advantage of the CCD. An object of the present invention is to provide an imaging system.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an imaging system using a CCD according to any one of claims 1 to 8 has an interline type CCD, and follows a horizontal direction and a vertical direction in an imaging surface of the CCD. By vertically transferring each pixel signal of a large number of image sensors arranged in a two-dimensional lattice pattern to a horizontal transfer path via a vertical transfer path, and horizontally transferring the pixel signal of the horizontal transfer path for each image sensor , A device that continuously captures image data of one screen composed of pixel signals of each of the plurality of image sensors at regular intervals, and is provided in a part of the imaging surface in at least one of the horizontal direction and the vertical direction. Position data including the center position of the target region and the partition direction of the virtual partition line. Based on the target area based on the above Timing determination means for determining the operation timing of each of the vertical transfer and horizontal transfer, and it is determined by the timing determination means that the respective operation timing has been reached. During the above target area And image reading means for controlling the vertical transfer and the horizontal transfer so as to continuously read pixel signals of the image pickup element group at an image pickup interval shorter than the predetermined interval.
[0010]
[Action]
In the photographing system using the CCD according to the first to eighth aspects of the present invention, an object divided by a virtual dividing line along at least one of the horizontal direction and the vertical direction in a part of the imaging surface of the CCD. Based on the position data indicating the position of the area on the imaging surface (position data including at least the center position of the target area and the dividing direction based on the virtual dividing line), Depending on the target area The respective operation timings of the vertical transfer and the horizontal transfer of the elementary signals are determined. Then, while it is determined that it is the operation time, Image from the target area By controlling the vertical transfer and the horizontal transfer of the elementary signals so as to have a shorter imaging interval, the image data of one screen including the pixel signals of the imaging element group in the target area as a whole is captured on the entire imaging surface. Reading is continuously performed at an imaging interval shorter than a certain interval.
[0011]
【Example】
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The imaging system using the CCD shown in FIG. 1 includes an interline CCD 1 that is an area image sensor and a device unit 2 related to the CCD 1. The video signal for the CCD 1 from the device unit 2 is output to the image display unit 4 (comprising D / A 4a, monitor 4b, etc.) via the image processing unit 3 (comprising A / D 3a, memory 3b, etc.). It is like that.
[0012]
The CCD 1 is a solid-state imaging device having a so-called two-phase or four-phase driving type internal structure, and has an imaging surface Ia on which light is incident through an optical system OP such as an objective lens, as shown in FIG. The center of the imaging surface Ia is arranged so as to be coaxial with the optical axis.
[0013]
Further, as shown in FIG. 2, the CCD 1 has a two-dimensional lattice-like position normalized in the horizontal direction (hereinafter referred to as “horizontal direction” for convenience) and the vertical direction (hereinafter referred to as “longitudinal direction” for convenience) of the imaging surface Ia. 5 and a plurality of light receiving sections (hereinafter referred to as “pixels” for convenience) 5... 5 arranged in the same vertical direction within the imaging surface Ia (hereinafter referred to as “vertical pixel groups” for convenience). ) V1... Vx (x = the number of pixels in the vertical direction), and a plurality of vertical transfer paths 6. The CCD 1 includes a horizontal pixel group at the end of a group of pixels arranged in the same horizontal direction in the imaging surface Ia (hereinafter referred to as “horizontal pixel group” for convenience) L1... Lm (m = number of pixels in the horizontal direction). A horizontal transfer path 7 for charge transfer connected to one end of each of the plurality of vertical transfer paths 6... 6 is disposed at an outer position substantially parallel to H1.
[0014]
With the above configuration, the CCD 1 receives a driving pulse from the device unit 2 and executes a required operation. That is, incident light from the optical system OP to the imaging surface Ia of the CCD 1 is converted and accumulated into signal charges (pixel signals) for each of the pixels 5... 5, and the signal charges are common to the vertical pixel groups V 1. Simultaneously transferred to the transfer paths 6 ... 6 (see arrow a1 in FIG. 2, this transfer is hereinafter referred to as "first transfer a1"). The signal charges of the vertical transfer paths 6... 6 are vertically transferred to the horizontal transfer path 7 for each horizontal pixel group L1... Lm (see arrow a2 in FIG. 2, hereinafter, this vertical transfer is referred to as “second transfer a2”). The signal charges on the horizontal transfer path 7 are serially sequentially transferred to the device unit 2 for reading (see arrow a3 in FIG. 2). Called transfer a3 ”).
[0015]
The device unit 2 includes a drive control unit 8 that controls the operation timing of each of the first to third transfers a1 to a3, and an analog to which a signal from the CCD 1 after the third transfer a3 by the drive control unit 8 is input. And a processing circuit 9.
[0016]
The drive control unit 8 determines the drive pulse pattern S1 corresponding to the imaging mode, the CPU 10 constituting the main part of the time determination means of the present invention, the drive clock generator 11 including a crystal oscillator that generates the reference clock CK, and the like. And a driving timing signal generating circuit (hereinafter simply referred to as “generating circuit”) 12 that outputs a driving pulse corresponding to the driving pulse pattern instructed by the CPU 10 to the CCD 1 and constitutes a main part of the image reading means of the present invention. . The drive control unit 8 is connected to an input device 13 for an operator to specify an imaging mode.
[0017]
As shown in FIG. 3, the generating circuit 12 outputs three driving pulses RΦ, VΦ, and PΦ that control the operation timing of the first to third transfers a1 to a3 to the CCD 1 and includes three flip-flops. Pulse generators P1... P3 and three counters C1... C3 for individually instructing the pulse generators P1. Each of the counters C1... C3 includes, for example, a program counter (built in the microprocessor) that can change the measurement value of the reference clock to be arbitrarily counted or its pattern according to the drive pulse pattern from the CPU 10, and It is designed to operate in synchronization with.
[0018]
The RΦ counter C1 constantly counts the reference clock number set according to the drive pulse pattern from the CPU 10, and when the counted value counts the reference clock number corresponding to the start timing of the first transfer a1, the RΦ pulse A pulse is output to the generator P1. Thereby, the RΦ pulse generator P1 raises the drive pulse RΦ from L to H, and the first transfer a1 by the CCD 1 is started.
[0019]
The VΦ counter C1 always counts the reference clock number set according to the drive pulse pattern from the CPU 10, and when the counted value counts the reference clock number corresponding to the start timing of the second transfer a2, the VΦ pulse A pulse is output to the generator P1. Thereby, the pulse generator P2 for VΦ raises the drive pulse VΦ from L to H, and the second transfer a2 for each horizontal pixel group by the CCD 1 is started.
[0020]
The PΦ counter C3 always counts the reference clock number set according to the drive pulse pattern from the CPU 10, and when the counted value counts the reference clock number corresponding to the start timing of the third transfer a3, the PΦ pulse A pulse is output to the generator P3. Thereby, the RΦ pulse generator P3 raises the drive pulse PΦ from L to H, and the third transfer a3 for each pixel in the horizontal pixel group by the CCD 1 is started.
[0021]
The analog processing circuit 8 is composed of an electronic circuit on which an amplifier and a filter are mounted, and is connected to the output terminal of the CCD 1. The analog processing circuit 8 receives the electric signal after the third transfer from the CCD 1, performs signal processing such as amplification and waveform shaping (noise removal, etc.) on the electric signal, and converts the analog signal after the signal processing into an image. It is supplied to the processing unit 4.
[0022]
Here, the operation principle of the high-speed imaging method according to the present invention will be described with reference to FIGS.
[0023]
First, for comparison, a normal imaging method (hereinafter, this imaging mode is referred to as “normal mode”) is taken as an example, and the imaging time is considered.
[0024]
Here, the CPU 10 of the drive control unit 7 holds a drive pulse pattern in the normal mode (hereinafter referred to as “normal pulse pattern S1”) as a default value in advance, and based on the normal pulse pattern S1 during normal imaging. Thus, the reference clock number to be counted by each of the counters C1 to C3 is determined.
[0025]
For example, considering the model of the imaging surface Ia composed of the horizontal pixel groups L1... L8 (scanning line number m = 8) shown in FIG. 4, the CCD 1 uses the drive pulses RΦ, VΦ corresponding to the normal pulse pattern S1 shown in FIG. , PΦ, as described above, the second transfer a2 and the third transfer a3 are alternately executed for each horizontal pixel group after the first transfer a1.
[0026]
Therefore, by generalizing the above model and defining the required times Rt, Vt, and Pt of the number m of scanning lines and the first to third transfers a1 to a3, the imaging time Fm per screen in this normal mode is theoretically Above, it is shown by the following calculation formula.
[0027]
[Expression 1]
Fm = Rt + m × (Vt + Pt) (1)
For example, the imaging time Fm per screen of the above model can be obtained by substituting the number of scans m = 8 into the equation (2).
[0028]
Next, regarding the high-speed imaging method (hereinafter, this imaging mode is referred to as “high-speed mode”), the operation principle and imaging time Fn will be considered while comparing with the normal mode.
[0029]
First, the classification of the target area A1 in the imaging surface Ia that is the target of the high-speed mode will be described (hereinafter, the area other than the target area A1 is referred to as “non-target area A2”).
[0030]
The target area A1 is roughly divided into two depending on whether or not the center point thereof coincides with the center point (optical axis) of the imaging surface Ia (hereinafter, for convenience, those that do not coincide with the optical axis are referred to as “mismatch mode”, Those that coincide with the optical axis are called “coincidence modes”). Further, the target area A2 is a “horizontal mode” in which the horizontal direction is a dividing line due to a difference in the dividing direction of the virtual dividing line along the horizontal direction and the vertical direction of the imaging surface Ia in each of the mismatch mode and the mismatch mode. And a “vertical mode” in which the vertical direction is a dividing line, and a “vertical and horizontal mode” in which the horizontal and vertical directions are dividing lines.
[0031]
The information about each high-speed mode is stored in advance by the CPU 10, and the CPU 10 collates each mode with the position information of the imaging mode specified by the operator operating the input device 13, and performs high-speed imaging. Drive pulse pattern (hereinafter referred to as “high-speed pulse pattern S2”) is determined, and the high-speed pulse pattern S2 can be individually output to each of the counters C1... C3.
[0032]
As shown in FIG. 6, the high-speed pulse pattern S2 is determined by changing a part of the normal pulse pattern S1 (drive pulses VΦ and PΦ) to a required pattern based on each mode. For example, the following five required patterns (“continuous VΦ”, “discard PΦ”, “omitted VΦ”, “abbreviated PΦ”, “partial PΦ”) are defined.
[0033]
First, “continuous VΦ” refers to the drive pulse VΦ that is continuously applied, and “discard PΦ” refers to the drive pulse PΦ that is applied after the continuous VΦ. Therefore, only the second transfer a2 of the horizontal pixel group is continuously executed by the continuous VΦ, and when the signal charge of the same vertical pixel group is accumulated in the horizontal transfer path 7, it is accumulated by the discard PΦ. The signal charges are read together as discard data. The continuous VΦ and the discard PΦ are selected mainly as a high-speed pulse pattern S2 corresponding to the horizontal mode (including the vertical and horizontal modes) (see, for example, FIG. 7B).
[0034]
Further, “omitted VΦ” means a drive pulse VΦ that should be omitted for a continuous horizontal pixel group including the last scanning line of one screen, and “omitted PΦ” is omitted as a pair with the omitted VΦ. This is the power drive pulse PΦ. Accordingly, the second and third transfers a2 are omitted by the omitted VΦ and PΦ, and the operation of the next screen is started thereafter. The omitted VΦ and PΦ are selected as the high-speed pulse pattern S2 corresponding to the horizontal mode (including the vertical and horizontal modes) in the coincidence mode (see, for example, FIG. 8D).
[0035]
“Partial PΦ” means that a drive pulse PΦ in which the period of the H level is changed is given. By this part PΦ, the third transfer a3 for each pixel of one horizontal pixel group is stopped at the intermediate pixel, and thereafter The next second transfer a1 is started by the drive pulse VΦ. This portion PΦ is selected as a high-speed pulse pattern S2 corresponding to the vertical mode (including the vertical and horizontal modes) (see, for example, FIG. 9).
[0036]
Hereinafter, the operation principle and imaging time will be described for each of the high-speed modes.
[0037]
FIGS. 7A and 7B illustrate the operating principle and imaging time of the horizontal mode 1 in the mismatch mode. The high-speed pulse pattern S2 corresponding to the horizontal mode 1 includes the continuous VΦ and the discard VΦ, and the timing is determined by the number m of scanning lines of the horizontal pixel groups L1... Lm in the target area A1. Yes. For example, when the model similar to the above is considered, in the target area A1 including the horizontal mode 1 shown in FIG. 7A, as shown in FIG. 7B, the signal charges of only the first horizontal pixel group L1. Is read in the same pulse pattern as in the normal mode, and then the signal charges of the horizontal pixel groups L5... L8 in the non-target region A2 are finally discarded in a state of being superimposed on the horizontal transfer path 7 by the continuous VΦ and the subsequent discard VΦ. It is good to read for use.
[0038]
Therefore, by generalizing the above model and defining the number of scanning lines m in the imaging plane Ia and the number of scanning lines n in the target area A1, the imaging time Fn per screen in the horizontal mode 1 is theoretically It is obtained by the calculation formula.
[0039]
[Expression 2]

For example, the imaging time Fn per screen of the above model can be obtained by substituting m = 8 and n = 4 into the equation (2).
[0040]
When the incident light amount on the imaging surface Ia is large as a whole and the signal charge for rejection is saturated in the horizontal transfer path 7, the number of discarded VΦ may be set to be increased. .
[0041]
The vertical mode 1 of the mismatch mode shown in FIG. 6 has the same operation and imaging time as the normal mode, and does not operate as the high-speed mode. Further, the vertical / horizontal mode 1 of the mismatch mode shown in the figure is almost the same as the horizontal mode 1 in terms of its operating principle and imaging time.
[0042]
FIGS. 8A to 8D illustrate the operation principle and the imaging time of the horizontal mode 2 in the coincidence mode. The high-speed pulse pattern S2 corresponding to the horizontal mode 2 is different from the horizontal mode 1 in that it includes the omitted VΦ and the omitted PΦ in addition to the continuous VΦ and the discard PΦ.
[0043]
For example, when the model similar to the above is considered, in the target area A1 including the horizontal mode 2 shown in FIG. 8A, as shown in FIG. 8B, the horizontal direction of the first (lower) non-target area A2a. The pixel groups L1 and L2 are collectively read by the continuous VΦ and the discard VΦ for rejection. Subsequently, after the horizontal pixel groups L3... L6 in the target area A1 are read with a normal pulse pattern, the horizontal pixel groups L7 and L8 in the last (upper) non-target area A2b are omitted by VΦ and omitted VΦ. As shown in (1), the reading of one screen is terminated in a state where the image is stopped at the position in the first non-target area A2a. That is, when reading the next screen, the signal charges of the horizontal pixel groups L7 and L8 of the previous screen are added to the signal charges of the horizontal pixel groups L1 and L2 of the next screen and read together for rejection by the continuous VΦ and the discard VΦ. be able to.
[0044]
Therefore, when the above model is generalized and the number of scanning lines m and n is defined as described above, the imaging time Fn per screen in the horizontal mode 2 is theoretically obtained by the following calculation formula.
[0045]
[Equation 3]

For example, the imaging time Fn per screen of the above model can be obtained by substituting m = 8 and n = 4 into equation (3).
[0046]
FIG. 9 explains the operating principle of the vertical mode 2 in the coincidence mode and its imaging time. The high-speed pulse pattern S2 corresponding to the horizontal mode 2 does not include the required mode such as the continuous VΦ common to the horizontal modes 1 and 2 but includes only the portion PΦ, and the timing is the number of vertical pixel groups in the target area A1. Determined by
[0047]
For example, when the model similar to the above is considered, in the target area A1 including the vertical mode 2 illustrated in FIG. 9, the vertical direction of the target area A1 is illustrated at the timing illustrated in FIG. After reading the signal charges up to the pixel group, the third transfer a3 is stopped and the second transfer a2 is executed. Thereby, the signal charge of the horizontal pixel group of the last (right side) non-target area Aa1 can be read for rejection by overlapping the signal charge of the horizontal pixel group of the next first (left side) non-target area A2a.
[0048]
Therefore, by generalizing the above model, in addition to the number m of scanning lines as described above, the scanning line length S determined by the number of vertical pixel groups in the imaging surface Ia and the scanning line determined by the number of vertical pixel groups in the target area A1. Is defined, the imaging time per screen Fn in the vertical mode 2 is theoretically obtained by the following calculation formula.
[0049]
[Expression 4]

For example, the imaging time Fn per screen of the above model can be obtained by substituting m = 8 and (S + Q) / (2 · S) = 2/3 into the equation (4).
[0050]
Note that the vertical / horizontal mode 2 in the coincidence mode can be arbitrarily set by a combination of the horizontal mode 2 and the vertical mode 2 as shown in FIG.
[0051]
Here, returning to the embodiment, the overall operation will be described based on FIG. 11 with a focus on the processing of the CPU 10 of the drive control unit 7. Here, it is assumed that the coincidence mode among the high-speed modes is set.
[0052]
First, it is assumed that the operator operates the input device 14 to instruct the position data of the target area in the high speed mode. In response to this instruction, the CPU 10 executes the processing shown in FIG. First, when the designated target area A1 is input in step S1, it is determined whether or not the target area A1 is in the horizontal direction, the vertical direction, or the vertical and horizontal direction in step S2. For example, if the vertical direction is determined, the position in the vertical direction is input in step S3a, and the vertical mode 2 is determined in step S4a. Also, in the case of the horizontal direction or the vertical / horizontal direction, the horizontal mode 2 or the vertical / horizontal mode 2 is determined by the same processing as in steps S3a and S4a.
[0053]
Next, in step S5, a high-speed pulse pattern S2 corresponding to the determined high-speed mode is determined and individually output to each of the counters C1 to C3. Therefore, each of the counters C1... C3 counts the count value of the reference clock based on the high-speed pulse pattern S2, so that the drive pulses RΦ, VΦ, and PΦ are output from the pulse generators P1.
[0054]
As described above, in this embodiment, the target area is set on the imaging surface of the CCD, and each transfer timing of the signal charge is controlled and read according to the position information of the target area. Speeding up can be realized, thereby enabling effective use of slow motion images and the like. Further, since it can be easily applied to a general CCD, the entire apparatus can be constructed at a low cost. Furthermore, when the coincidence mode is adopted as the high-speed mode, the center of the image and the center of the lens can always coincide with each other, so that a slow motion image can be displayed at a center position having a relatively excellent lens resolving power. The operability is improved.
[0055]
In the above-described embodiment, the horizontal pixel is swept away in the state where unnecessary pixel signals are added to the horizontal transfer path by the continuous VΦ and the discard VΦ in the horizontal mode, but the present invention is not necessarily limited thereto. . For example, when a CCD having a function of sweeping away to the drain or the like is used, it may be applied to sweep away from the horizontal transfer path to the drain or the like. In this case, the horizontal transfer (third transfer) at the time of discard VΦ can be omitted, and the speed can be further increased by the omission.
[0056]
(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the configuration for the high speed mode of the first embodiment is partially changed. Here, the same or equivalent components in the first embodiment are given the same or equivalent reference numerals, and the description thereof will be simplified or omitted.
[0057]
In the imaging system using the CCD shown in FIG. 12, a light-shielding portion 14 that is a light transmissive member that operates in the high-speed mode is disposed between the CCD 1 and the optical system OP. For example, the light-shielding portion 14 includes an openable / closable light-shielding mask 15 having an opening of at least the same size as the imaging surface Ia of the CCD 1 and a substantially rectangular opening state of the mask 15 in the vertical direction in the imaging surface Ia. And a mask opening / closing mechanism 16 including a step motor for opening and closing along the lateral direction. The mask opening / closing mechanism 16 receives position data S4 related to each target area A1 for the high speed mode from the drive control unit 7, and controls the opening / closing state of the mask 15.
[0058]
With the above configuration, the light shielding unit 14 causes the light from the objective optical system OP to enter only the target region A1 in the imaging surface Ia of the CCD 1 through the opening of the mask 15.
[0059]
Here, the operation principle and imaging time of the high-speed mode using the mask 15 (hereinafter referred to as “mask high-speed mode”) will be described.
[0060]
First, in the target area A1 in the imaging surface Ia to be the target of the mask high-speed mode, “horizontal mode”, “vertical mode”, “match mode” and “mismatch mode” similar to the high-speed mode, respectively, And “vertical / horizontal mode”, and in addition to this, “high-speed vertical mode” (described later) is newly set (see FIG. 13).
[0061]
Further, in the high-speed pulse pattern S3 corresponding to each of the mask high-speed modes, as shown in FIG. 13, “discard PΦ” among the five required patterns is excluded. This is because, when the mask 14 is used, the light is shielded and does not enter the non-target region A2, and therefore, for example, a dark current generation situation due to the influence of diffracted light or the like is assumed. This is because the signal charge of each pixel may be assumed to be zero. That is, if the signal charge in the non-target area A2 is set to 0, a pattern in which the signal charge in the target area A1 is superimposed at this position may be assumed.
[0062]
Hereinafter, the operation principle and the imaging time will be described for each mask high-speed mode.
[0063]
FIGS. 14A and 14B illustrate the operation principle and imaging time of the mask lateral mode 1 in the mismatch mode. Compared with the horizontal mode 2, the high-speed pulse pattern S3 corresponding to the mask horizontal mode 1 includes only the omitted VΦ and the omitted PΦ without the continuous VΦ and the discard VΦ, and the timing thereof is the horizontal pixel group of the target area A1. It is determined by the number m of scanning lines L1. For example, when the model similar to the above is considered, in the target area A1 including the horizontal mode 1 shown in FIG. 14A, the horizontal pixel group L1 of the first target area A1 at the timing shown in FIG. A signal charge of only L4 is read in the same pulse pattern as in the normal mode, and the horizontal pixel group L5... L8 in the subsequent non-target region A2 is stopped at a position in the target region A1 by the omitted VΦ and the omitted VΦ. Finish reading. Since the signal charges of the horizontal pixel groups L5... L8 can be regarded as 0, even if the signal charges of the horizontal pixel groups L1. That is, the next screen reading can be executed after the above-mentioned one screen reading is completed.
[0064]
Therefore, when the above model is generalized and the number n of scanning lines in the target area A1 is defined as described above, the imaging time Fn per screen is theoretically obtained by the following calculation formula.
[0065]
[Equation 5]
Fn = Rt + n × (Vt + Pt) (5a)
For example, the imaging time Fn per screen of the above model can be obtained by substituting n = 4 into the equation (2). In general, since the relationship of Rt << n × (Vt + Pt) is assumed, assuming that Rt is 0, the imaging time ratio R between the imaging time Fn in the mask lateral mode 1 and the imaging time Fm in the normal mode is It becomes.
[0066]
[Formula 6]

[0067]
FIGS. 15A and 15B illustrate the operation principle and imaging time of the mask vertical mode 1 in the mismatch mode. The high-speed pulse pattern S3 corresponding to the mask vertical mode 1 includes only the portion PΦ as in the vertical mode 2, and the timing is determined by the number of vertical pixel groups in the target area A1. For example, when the model similar to the above is considered, in the target area A1 composed of the vertical mode 2 shown in FIG. 15A, the timing shown in FIG. Thus, after reading the signal charges of the vertical pixel group in the target area A1, the third transfer a3 is stopped and the second transfer a2 is executed. That is, even if the signal charge of the horizontal pixel group of the next target area A1 is superimposed on the O signal charge of the horizontal pixel group of the non-target area A2, there is substantially no influence.
[0068]
Therefore, when the above model is generalized and the same scanning line number m, scanning line length S, and partial length Q as above are defined, the imaging time Fn per screen is theoretically obtained by the following calculation formula.
[0069]
[Expression 7]

For example, the imaging time Fn per screen of the above model can be obtained by substituting m = 8 and (Q / S) = 1/2 into the equation (6a). Here, since the relationship of Rt << n × (Vt + Pt) and Vt << Pt is generally satisfied, assuming that Rt and Pt are O, the imaging time Fn in the mask vertical mode 1 and the imaging time Fm (in normal mode) The imaging time ratio R with the expression (1) is as follows.
[0070]
[Equation 8]

[0071]
FIGS. 16A and 16B illustrate the operation principle and imaging time of the mask vertical / horizontal mode 1 in the mismatch mode. The high-speed pulse pattern S3 corresponding to the mask vertical and horizontal mode 1 is a combination of the mask horizontal and vertical mode 1 patterns. For example, when the model similar to the above is considered, in the target area A1 including the mask vertical / horizontal mode 2 shown in FIG. 16A, the horizontal pixel groups L1... L4 of the target area A1 at the timing shown in FIG. And the abbreviations VΦ and PΦ that target the horizontal pixel groups L5... L8 that are part of the non-target region A2.
[0072]
Therefore, by generalizing the above model and defining the same scanning lines m, n, scanning line length S, and partial length Q as described above, the imaging time Fn per screen in the mask vertical / horizontal mode 2 is theoretically It is obtained by the calculation formula.
[0073]
[Equation 9]

For example, the imaging time Fn per screen of the above model can be obtained by substituting n = 8 and (Q / S) = 1/2 into the equation (7a). Here, since the relationship of Rt << n × (Vt + Pt) and Vt << Pt is generally satisfied, when Rt and Pt are regarded as 0, the imaging time Fn in the mask vertical / horizontal mode 1 and the imaging time Fm (in normal mode) The imaging time ratio R with the expression (1) is as follows.
[0074]
[Expression 10]

[0075]
FIGS. 17A and 17B illustrate the operation principle and imaging time of the mask horizontal mode 2 in the coincidence mode. The high-speed pulse pattern S3 corresponding to the mask horizontal mode 2 is different from the above-described horizontal mode 2 in that the discard PΦ is excluded. For example, when the model similar to the above is considered, in the target area A1 including the horizontal mode 2 shown in FIG. 17A, the horizontal pixel group L1 of the first non-target area A2a is shown at the timing shown in FIG. And L2 are accumulated in the horizontal transfer path by the continuous VΦ (signal charge is 0), the horizontal pixel groups L3... L6 in the target area A1 are read in the normal pulse pattern. Subsequently, the reading of one screen is terminated in a state where the horizontal pixel groups L7 and L8 of the upper non-target region A2b are stopped at the position in the lower non-target region A2a by the omitted VΦ and the omitted VΦ. That is, when the next screen is read, the horizontal pixel groups L7 and L8 of the previous screen are stored in the horizontal transfer path together with the horizontal pixel groups L1 and L2 of the next screen (signal charge is 0) by continuous VΦ.
[0076]
Therefore, when the above model is generalized and the number of scanning lines m and n is defined in the same manner as described above, the imaging time Fn per screen is theoretically obtained by the following calculation formula.
[0077]
[Expression 11]

For example, the imaging time Fn per screen of the above model can be obtained by substituting m = 8 and n = 4 into equation (3).
[0078]
FIG. 18 explains the operation principle and the imaging time of the mask vertical mode 2 in the coincidence mode. The high-speed pulse pattern S3 corresponding to the mask vertical mode 2 includes only the portion PΦ, and the timing is determined by the number of vertical pixel groups in the target area A1. For example, when the model similar to the above is considered, in the target area A1 including the mask vertical mode 2 shown in FIG. 18, the target P at the timing shown in FIG. After reading the signal charges up to the vertical pixel group in the area A1, the third transfer a3 is stopped and the second transfer a2 is executed. That is, the signal charge (almost 0) of the horizontal pixel group in the right non-target area A2b may be read together with the signal charge (almost 0) of the horizontal pixel group in the left non-target area A2a at the next third transfer a3.
[0079]
Therefore, if the number of scanning lines m, the scanning line length S, and the partial length Q are defined by generalizing the above model, the imaging time Fn per screen is theoretically obtained by the following calculation formula.
[0080]
[Expression 12]

[0081]
FIG. 19 explains the principle of operation of the mask high-speed vertical mode in the coincidence mode and the imaging time thereof. This mask high-speed vertical mode is intended to increase the speed of the mask vertical mode 2 and shortens the operation period of the portion PΦ of the corresponding high-speed pulse pattern S3. For example, when a model similar to the above is considered, in the target area A1 from the mask high-speed vertical mode shown in FIG. 19, the portion PΦ for all horizontal pixel groups is used at the timing shown in FIG. The second transfer a2 is executed before or during the start of reading of the horizontal pixel group. In other words, if the signal charges in the left and right non-target areas A2a and A2b are regarded as 0, even if the signal charges in the target area A1 are superimposed on the non-target areas A2a and A2b, there is substantially no influence. Because.
[0082]
Therefore, if the number of scanning lines m, the scanning line length S, and the partial length Q are defined by generalizing the above model, the imaging time Fn per screen is theoretically obtained by the following calculation formula.
[0083]
[Formula 13]

[0084]
Note that the mask vertical / horizontal mode 2 in the matching mode shown in FIG. 20 is set by arbitrarily combining the mask horizontal mode 2 and the mask vertical mode 2 (including the high-speed vertical mode). As for the vertical and horizontal modes, for example, as shown in FIG. 21, the horizontal and vertical modes 2 according to the first embodiment and the mask horizontal and vertical modes 2 (including the high-speed vertical mode) according to the present embodiment are mutually connected. It is also possible to set the composite vertical / horizontal modes 1 and 2 in combination.
[0085]
As described above, in this embodiment, in addition to the same operation as the first embodiment, the opening shape of the mask 15 of the light shielding portion 14 is arbitrarily changed by the position data S4 from the CPU 10 of the drive control portion. . Other operations are executed in accordance with the mask high-speed mode. The light-shielding portion 14 is not limited to the configuration of the mask and the mask opening / closing mechanism. For example, the light-transmitting liquid crystal display is used to display the opening shape corresponding to the target area A1 and display the display. You may employ | adopt the structure which permeate | transmits light only to opening. Moreover, the structure which opens and closes a mask manually may be sufficient.
[0086]
As described above, with regard to representative ones of the high-speed modes according to the first and second embodiments, a practical numerical value (Rt) in which about 1/2 of the imaging surface Ia is the target area is calculated in the calculation formula of the imaging time Fn. = 1, Vt = 1, Pt = 500, m = 500, n = 250, S = 500, Q = 250), and the following results were obtained.
[0087]
First, the transverse mode 1 (equation (2)) in the mismatch mode according to the first embodiment (without mask), the transverse mode 2 (equation (3)) in the coincidence mode, and the longitudinal mode 2 ((4) The imaging time of each of the formulas was Fn = 126K (K = 1,000), 126K, and 188K. Further, in the coincidence mode according to the second embodiment, each of the imaging in the mask horizontal mode 2 (expression (8)), the mask vertical mode 2 (expression (9)), and the mask vertical high-speed mode (expression (10)). Times were Fn = 125K, 188K, and 125K.
[0088]
That is, there is almost no difference in the imaging time in the horizontal mode in any high-speed mode, and the imaging speed in the vertical mode is the highest in the mask high-speed vertical mode. Incidentally, the imaging time in the normal mode (equation (1)) was Fm = 250K. Therefore, theoretically, for example, when about 1/2 of the imaging surface Ia is set as the target area A1 in the high speed mode, compared with the normal mode, about 1/2 in the horizontal mode and the high-speed mask vertical mode, and 3 / in the vertical mode. It was confirmed that the imaging time can be shortened by about 4, that is, the speed can be increased.
[0089]
The configuration of the drive control unit according to the first and second embodiments is not necessarily limited to the above. For example, FIG. 22 illustrates the flow of the basic concept of the operation principle of the drive control unit, and any operation is possible as long as the operations of steps 100 to 106 can be realized as shown in FIG. In other words, any circuit configuration capable of realizing the operation represented by the counters in steps 100, 101, 103 (and 104) and the processing of the microcomputer, etc. represented in step 102 may be used.
[0090]
Therefore, the drive control unit may be configured to set a counter value to be counted from the outside to the counter, or may be configured to include a plurality of counter circuits corresponding to each of the high speed modes. In short, the drive control unit may be a circuit that can generate a drive signal necessary for the operation principle of the high-speed mode. For example, the CPU used in the first and second embodiments is not used as a main part configuration, and the flip-flop It is also possible to configure with a digital circuit whose main part is.
[0091]
【The invention's effect】
As described above, in the imaging system using the CCD according to the first to eighth aspects of the invention, a part of the CCD imaging surface is divided by the virtual dividing line along at least one of the horizontal direction and the vertical direction. Based on the position data including the center position of the target area and the partitioning direction of the virtual partition line. According to the target area The timing judging means for judging the respective operation timings of the vertical transfer and the horizontal transfer, and it is judged by the timing judging means that the respective operation timings have been reached. During the above target area The pixel signals of the image sensor groups are continuously read at an imaging interval shorter than the predetermined interval. So Since the image reading means for controlling the direct transfer and the horizontal transfer is provided, it is possible to reduce the number of pixels read by the CCD, to shorten the imaging time per screen, and to increase the imaging speed.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing an overall configuration of an imaging system using a CCD according to first and second embodiments.
FIG. 2 is a schematic explanatory diagram of an imaging surface of a CCD.
FIG. 3 is a schematic block diagram showing a main configuration of a drive control unit.
FIG. 4 is a schematic diagram of a model for explaining the operating principle of a CCD during normal imaging.
FIG. 5 is a timing chart showing the operation of each part of the model shown in FIG. 4;
FIG. 6 is a correspondence diagram between types of high-speed modes and pulse patterns in the first embodiment.
7A and 7B are models for explaining the operation principle of the transverse mode in the mismatch mode, where FIG. 7A is a schematic diagram, and FIG. 7B is a schematic timing chart.
FIG. 8 is a model for explaining the operation principle of the transverse mode in the coincidence mode, wherein (a) to (c) are schematic diagrams, and (d) is a schematic timing chart.
FIG. 9 is a schematic diagram of a model for explaining an operation principle of a longitudinal mode in a coincidence mode.
FIG. 10 is a schematic diagram of a model for explaining a vertical / horizontal mode in a coincidence mode.
FIG. 11 is a schematic flowchart showing processing of a CPU of a drive control unit.
FIG. 12 is a schematic block diagram showing a main configuration of an imaging system using a CCD according to a second embodiment.
FIG. 13 is a correspondence diagram between types of mask high-speed modes and pulse patterns according to the second embodiment.
14A and 14B are diagrams for explaining the operation principle of the mask transverse mode in the mismatch mode. FIG. 14A is a schematic diagram, and FIG. 14B is a schematic timing chart.
15A and 15B are models for explaining the operation principle of the mask longitudinal mode in the mismatch mode, where FIG. 15A is a schematic diagram, and FIG. 15B is a schematic timing chart.
16A and 16B are models for explaining the operation principle of the mask vertical / horizontal mode in the mismatch mode, where FIG. 16A is a schematic diagram, and FIG. 16B is a schematic timing chart;
FIGS. 17A and 17B are models for explaining the operation principle of the mask transverse mode in the coincidence mode, where FIG. 17A is a schematic diagram, and FIG. 17B is a schematic timing chart;
18A and 18B are diagrams for explaining the operation principle of the mask vertical mode in the coincidence mode, where FIG. 18A is a schematic diagram, and FIG. 18B is a schematic timing chart.
FIG. 19 is a schematic diagram of a model for explaining the operation principle of the mask high-speed vertical mode in the coincidence mode.
FIG. 20 is a schematic diagram of a model for explaining a mask vertical / horizontal mode in a coincidence mode.
FIG. 21 is a combination correspondence diagram of composite modes.
FIG. 22 is a schematic flowchart for explaining the flow of the concept of the operation principle of the drive control unit of the first and second embodiments.
[Explanation of symbols]
1 CCD
2 Device section
3 Image processing section
4 Image display section
Ia Imaging surface
5 Image sensor
6 Vertical transfer path
7 Horizontal transfer path
8 Drive controller
10 CPU

Claims (8)

An interline type CCD is provided, and each pixel signal of a large number of image sensors arranged in a two-dimensional lattice along the horizontal and vertical directions in the imaging surface of the CCD is transferred to the horizontal transfer path via the vertical transfer path. By vertically transferring the pixel signals of the horizontal transfer path for each image sensor, the image data of one screen composed of the pixel signals of the many image sensors is continuously imaged at regular intervals. In an imaging system using a CCD,
Data indicating a position on the imaging plane of a target area divided by a virtual dividing line along at least one of the horizontal direction or the vertical direction in a part of the imaging plane, the center position of the target area and the virtual Timing determination means for determining the respective operation timings of the vertical transfer and the horizontal transfer according to the target area based on position data including the dividing direction of the dividing line;
While it is determined by the timing determination means that the respective operation timings have been reached, the vertical transfer and horizontal transfer are performed so that the pixel signals of the imaging element group in the target area are continuously read at an imaging interval shorter than the predetermined interval. An image reading system using a CCD, comprising: an image reading unit that controls transfer.   The imaging system using a CCD according to claim 1, wherein the center position is set to a center position of the imaging surface.   The division direction is set along the horizontal direction, and the imaging interval is determined according to the number of vertical imaging elements in the target area divided along the horizontal direction or the length in the vertical direction. Item 3. An imaging system using the CCD according to item 1 or 2. The operation timing is the timing for adding the pixel signals of the imaging element group other than the target region that put on the imaging surface in the horizontal transfer path, and when to reject collectively pixel signal added to the horizontal transfer path The imaging system using CCD as described in any one of Claims 1 thru | or 3 containing these.   The division direction is set along the vertical direction, and the imaging interval is determined according to the number of horizontal imaging elements in the target area divided along the vertical direction or the length in the horizontal direction. Item 3. An imaging system using the CCD according to Item 2.   The imaging system using a CCD according to claim 1, further comprising a light transmitting body that allows light to enter a target area in the imaging surface.   The imaging system using a CCD according to claim 6, wherein the light transmitting body includes a variable mask mechanism having an opening for allowing light to enter a set target region.   The imaging system using a CCD according to claim 6, wherein the operation time includes a time when a pixel signal of an image sensor group in the target area and a pixel signal of an image sensor group other than the target area are superimposed on each other.

Images