JP4593805B2 - Auto focus camera - Google Patents

Description

と求められる。ただし、ｍはカメラのファインダー光学系で決まる定数である。
ここで視線の個人差を補正する係数はＡ１、Ｂ１と二つであるため、例えば使用者に位置の異なる二つの視標を見てもらい、該指標の位置と上記（５）式に従い算出された固視点の位置とを一致させることにより、前記係数Ａ１，Ｂ１を求めることが可能である。
【００３０】
このようにして、撮影者が撮影画面のどこを見ているのかを検出する事により、検出された座標（ｘｎ，ｙｎ）に最も近い位置に存在する焦点検出点を、撮影レンズの焦点調節動作を行うための焦点検出点として決定できる。
【００３１】
【発明が解決しようとする課題】
カメラが焦点検出点から得られる被写体空間情報をもとに、撮影レンズの焦点調節動作を行う焦点検出点を決定する従来方式の自動選択アルゴリズムにおいては、一連のグルーピング手法によって、全ての焦点検出点から一部の焦点検出点が抽出され、さらに撮影画面上の焦点検出点の相対位置によって対象とする焦点検出点は絞り込まれ、最終的に近点優先の原理によって一つの焦点検出点が選択されている。すなわち、撮影画面上に存在する焦点検出点は、各情報によって篩に掛けられ、それぞれの情報で１つでも条件を満足しない場合には、最終的に撮影レンズの焦点調節動作を行うための焦点検出点として選択されない仕組みになっている。
【００３２】
このアルゴリズムでは、撮影画面上の焦点検出点が増えた場合を考えると、互いに近傍に存在する隣接した２つの焦点検出点においても、各条件を当てはめたとき、微妙な差異によってでも篩で分断されてしまうことが生じ、極端に異なる結果が得られることになる。
【００３３】
従って、このような篩方式による焦点検出点の抽出方法は、特定の焦点検出点が選択されにくかったり、被写体やカメラの構え方のわずかな変化によって、大きく異なるピント結果が得られることになる。
【００３４】
また自動選択アルゴリズムにおいては、本質的にカメラが撮影者の意図を予測している点からして、撮影シーンによっては撮影者の意図する焦点検出点とはずれが生じる事は避けられない。例えば図２０のように、撮影画面上主被写体となる候補が２つ以上存在する場合、自動選択アルゴリズムによると手前の花にピントが合される。しかし実際には、撮影者は手前をぼかして奥の花を主被写体としてピントを合わせたかったのかもしれない。
【００３５】
さらに、図２１のようなシーンにおいて、手前の植木と中央付近の車では、自動選択アルゴリズムでは、近点優先の原理から手前の植木にピントを合わせることになる。撮影者が観察すれば主被写体になりにくいと容易に判断できる物体でも、自動選択アルゴリズムは、被写体情報であるデフォーカス量から一律に主被写体を予測するので、撮影者の意思情報がない以上、このような問題が必然的に残ってしまう。
【００３６】
一方で撮影者の眼球像を観察する事により、視線方向を検出して撮影レンズの焦点調節動作を行う焦点検出点を決定する、視線選択アルゴリズムでは、算出される撮影画面上での座標が必ずしも撮影者が意図していた座標とは一致しないという問題がある。この原因は数多く確認されているが、代表的なものとして、眼球動作が無意識のうちに続けられていたり、周辺視野でもって外界を観察する事があることから、視線を捉えればその人が何を観察しているのかを必ず検出できるとは限らない点、睫や瞼が瞳孔に掛かったり、外乱光によって偶発的に生じる像の乱れによって取得眼球画像に不具合が生じる点、撮影ごとに変化するカメラの構え方による点、周辺照度変化による瞳孔径の変化や回転角の変化による点などが挙げられる。
【００３７】
以上のように従来方式による自動選択アルゴリズム、視線選択アルゴリズム双方にそれぞれ問題があり、撮影者は思い通りの焦点検出点を選択することに必ずしも成功するとは限らなかったのである。
【００３８】
（発明の目的）
本発明の目的は、複数の焦点検出点のうち特定の焦点検出点が選択されにくかったり、被写体やカメラの構え方のわずかな変化によって大きくピントがずれてしまうといったことを無くすことのできる自動焦点カメラを提供しようとするものである。
【００３９】
【課題を解決するための手段】
上記目的を達成するために、本発明は、撮影画面上の複数の焦点検出点のうちの１つの焦点検出点を選択し、該焦点検出点にて得られる焦点検出情報によって撮影レンズの焦点調節動作を行う合焦手段を有する自動焦点カメラにおいて、焦点検出点ごとにデフォーカス量を検出する第１の検出手段と、姿勢を検出する第２の検出手段と、前記第１の検出手段によって検出された複数の焦点検出点に対応するデフォーカス量から最も近い１の焦点検出点および当該１の焦点検出点に離散していて且つ無限遠側のデフォーカス量を示す焦点検出点の点数を当該１の焦点検出点に離散していなく且つ無限遠側のデフォーカス量を示す焦点検出点の点数よりも高い点数を付与するとともに、前記第２の検出手段によって検出された姿勢に基づいて予め定められた点数化マップに従って前記複数の焦点検出点の各々に対して点数を付与する点数化手段とを有し、前記合焦手段は、前記点数化手段により、付与された前記複数の焦点検出点の点数をそれぞれの焦点検出点毎に合計した数値の多寡により、前記複数の焦点検出点のうちの１つの焦点検出点を選択して撮影レンズの焦点調節動作を行う自動焦点カメラとするものである。
【００４０】
【発明の実施の形態】
以下、本発明を図示の実施の形態に基づいて詳細に説明する。
【００４１】
図１は本発明を一眼レフカメラに適用したときの実施の一形態を示す要部概略図である。
【００４２】
図１において、１は撮影レンズで、便宜上２枚のレンズで示したが、実際はさらに多数のレンズから構成されている。２は主ミラーで、ファインダ系による被写体像の観察状態と被写体像の撮影状態に応じて撮影光路へ斜設され或は退去される。３はサブミラーで、主ミラー２を透過した光束をカメラボディの下方の後述する焦点検出装置６へ向けて反射する。４はシャッタ、５は感光部材で、銀塩フィルム或はＣＣＤやＭＯＳ型等の固体撮像素子等である。６は焦点検出装置であり、結像面近傍に配置されたフィールドレンズ６ａ，反射ミラー６ｂ及び６ｃ，二次結像レンズ６ｄ，絞り６ｅ、複数のＣＣＤから成るラインセンサ６ｆ等から構成されている。
【００４３】
この実施の形態における焦点検出装置６は、周知の位相差方式にて焦点検出を行うものであり、図３に示すように、撮影画面内（ファインダ視野内）の複数の領域である２００〜２０６（７箇所）を焦点検出点として、該焦点検出点が焦点検出可能となるように構成されている。
７は撮影レンズ１の予定結像面に配置されたピント板、８はファインダ光路変更用のペンタプリズム、９，１０は各々観察画面内の被写体輝度を測定するための結像レンズと測光センサである。結像レンズ９はペンタプリズム８内の反射光路を介してピント板７と測光センサ１０を共役に関係付けている。
【００４４】
上記ペンタプリズム８の射出後方には光分割器１１ａを備えた接眼レンズ１１が配置され、使用者の眼１５によるピント板７の観察に使用される。光分割器１１ａは、例えば可視光を透過し赤外光を反射するダイクロイックミラーより成っている。１２は受光レンズ、１４はＣＣＤ等の光電変換素子列を二次元的に配したイメージセンサで、受光レンズ１２に関して所定の位置にある使用者の眼球１５の瞳孔近傍と共役になるように配置されている。１３ａ〜１３ｆは各々照明光源であるところの赤外発光ダイオードである。
【００４５】
２１は明るい被写体の中でも視認できる高輝度のスーパーインポーズ用ＬＥＤで、ここから発光された光は投光用プリズム２２を介し、主ミラー２で反射されてピント板７の表示部に設けた微小プリズムアレイ７ａで垂直方向に曲げられ、ペンタプリズム８，接眼レンズ１１を通って使用者の眼１５に達する。
【００４６】
そこで、ピント板７の焦点検出点に対応する複数の位置にこの微小プリズムアレイ７ａを枠状に形成し、これを各々に対応した７つのスーパーインポーズ用ＬＥＤ２１（各々をＬＥＤ−Ｌ１，ＬＥＤ−Ｌ２，ＬＥＤ−Ｃ，ＬＥＤ−Ｒ１，ＬＥＤ−Ｒ２，ＬＥＤ−Ｕ，ＬＥＤ−Ｄとする）によって照明する。これによって前述のように、図３に示したファインダ視野において、各々の焦点検出点２００，２０１，２０２，２０３，２０４，２０５，２０６がファインダー視野内で光り、焦点検出点を表示させることができるものである。２３はファインダ視野領域を形成する視野マスク、２４はファインダ視野外に撮影情報を表示するためのファインダ内ＬＣＤで、照明用ＬＥＤ（Ｆ−ＬＥＤ）２５によって照明される。上記ファインダ内ＬＣＤ２４を透過した光は三角プリズム２６によってファインダ視野外に導かれ、図３に示した様に使用者に各種の撮影情報を視認させることができる。
【００４７】
２７はカメラの姿勢を検出するための公知の姿勢センサであり、この出力によりカメラが縦位置に構えられているのか、横位置に構えられているのかといった情報を検出する。
【００４８】
３１は撮影レンズ１内に設けた絞り、３２は後述する絞り駆動回路１１１を含む絞り駆動装置、３３はレンズ駆動用モータ、３４は駆動ギヤ等から成るレンズ駆動部材である。３５はフォトカプラで、前記レンズ駆動部材３４に連動するパルス板３６の回転を検知して焦点調節回路１１０に伝えている。焦点調節回路１１０は、この情報とカメラ側からのレンズ駆動量の情報に基づいて前記レンズ駆動用モータ３３を所定量駆動させ、撮影レンズ１を合焦位置に移動させるようになっている。３７は公知のカメラとレンズとのインターフェイスとなるマウント接点である。
【００４９】
図２（Ａ），（Ｂ）は、上記の構成より成る一眼レフカメラの上面と背面の概略図である。図２において、４１はレリーズ釦であり、４２は外部モニタ表示装置としてのモニタ用ＬＣＤである。４４は撮影モード等の選択を行うためのモードダイヤルである。
【００５０】
４５は他の操作部材及びモードと組み合わせることによって、種々の設定値を設定するための回転式電子ダイヤルである。４６は、本発明の特徴と直接かかわる、画面内の複数の焦点検出点２００〜２０６のいずれかを用いて、焦点検出を行うかを選択する焦点検出点選択釦である。この動作については後で詳細に説明する。また、他の図２に記載されている操作部材は本発明と特に関係しない為、説明を省略する。
【００５１】
図４は上記構成の一眼レフカメラに内蔵された電気回路図であり、図１と同じ部分は同一符号を付してある。
【００５２】
カメラ本体に内蔵されたマイクロコンピュータ（以下、ＣＰＵと記す）１００には、視線検出回路１０１、測光回路１０２、自動焦点検出回路１０３、信号入力回路１０４、ＬＣＤ駆動回路１０５、ＬＥＤ駆動回路１０６、ＩＲＥＤ駆動回路１０７、シャッタ制御回路１０８、モータ制御回路１０９が接続されている。また、撮影レンズ１内に配置された焦点調節回路１１０、絞り駆動回路１１１とは、図１で示したマウント接点３７を介して信号の伝達がなされる。
【００５３】
ＣＰＵ１００に付随したＥＥＰＲＯＭ１００ａは記憶手段としての視線の個人差を補正する視線補正データの記憶機能を有している。前記視線検出回路１０１は、イメージセンサ１４（ＣＣＤ−ＥＹＥ）からの眼球像の信号をＡ／Ｄ変換し、この像情報をＣＰＵ１００に送信する。ＣＰＵ１００は後述するように視線検出に必要な眼球像の各特徴点を所定のアルゴリズムにしたがって抽出し、さらに各特徴点の位置から使用者の視線を算出する。
【００５４】
ラインセンサ６ｆは、前述の図３に示すファインダ視野内の７つの焦点検出点２００〜２０６に対応した７組のラインセンサＣＣＤ−Ｌ２，ＣＣＤ−Ｌ１，ＣＣＤ−Ｃ，ＣＣＤ−Ｒ１，ＣＣＤ−Ｒ２，ＣＣＤ−Ｕ，ＣＣＤ−Ｄから構成される公知のＣＣＤラインセンサである。前記自動焦点検出回路１０３は、上記のラインセンサ６ｆから得た電圧をＡ／Ｄ変換し、ＣＰＵ１００に送る。
【００５５】
ＳＷ１はレリーズ釦４１の第１ストロークでオンし、測光，ＡＦ，視線検出動作等を開始させる為のスイッチ、ＳＷ２はレリーズ釦の第２ストロークでオンするレリーズスイッチ、ＳＷ−ＡＥＬは４３のＡＥロック釦を押すことによってオンするＡＥロックスイッチ、ＳＷ−ＤＩＡＬ１とＳＷ−ＤＩＡＬ２は、４５の電子ダイアル内に設けられたダイアルスイッチで、信号入力回路１０４のアップダウンカウンタに入力され、この電子ダイアルの回転クリック量がここでカウントされる。
【００５６】
前記ＬＣＤ駆動回路１０５は、ファインダ内ＬＣＤ２４やモニタ用ＬＣＤ４２を表示駆動させるための公知の構成より成るもので、ＣＰＵ１００からの信号に従い、絞り値，シャッタ秒時，設定した撮影モード等の表示をモニタ用ＬＣＤ４２とファインダ内ＬＣＤ２４の両方に同時に表示させることができる。
【００５７】
前記ＬＥＤ駆動回路１０６は、照明用ＬＥＤ（Ｆ−ＬＥＤ）２５とスーパーインポーズ用ＬＥＤ２１を点灯，点滅制御する。前記ＩＲＥＤ駆動回路１０７は、赤外発光ダイオード（ＩＲＥＤ１〜６）１３ａ〜１３ｆを状況に応じて選択的に点灯させる。
【００５８】
前記シャッタ制御回路１０８は、通電すると先幕を走行させるマグネットＭＧ−１と、後幕を走行させるマグネットＭＧ−２を制御し、感光部材に所定光量を露光させる。前記モータ制御回路１０９は、フィルムの巻き上げ、巻き戻しを行うモータＭ１と主ミラー２及びシャッタ４のチャージを行うモータＭ２を制御するためのものである。
【００５９】
これらのシャッタ制御回路１０８、モータ制御回路１０９によって一連のカメラのレリーズシーケンスが動作する。
【００６０】
次に、本実施の形態における複数の焦点検出点から実際に撮影レンズの焦点調節動作を行うために用いられる焦点検出点を選択する方法について説明する。
【００６１】
図５（Ａ）〜（Ｈ）は、焦点検出点選択釦４６を押下ながら電子ダイヤル４５を時計方向にクリック回転させるごとに（Ａ）→（Ｂ）→…→（Ｈ）とファインダ内のスーパーインポーズ表示が順次変化し、さらにもう１クリック回転させることで（Ａ）に戻る様子を示している。また、反時計方向に電子ダイヤル４５を回転させたときには、図５の矢印とは正反対の順に表示を行う。
【００６２】
図５（Ａ）の表示状態において、他の操作部材の操作に移行すると、カメラが７つの焦点検出点２００〜２０６より撮影レンズの焦点調節動作を行うための焦点検出点を、各焦点検出点のデフォーカス量の状態、および焦点検出点の相対位置、および撮影者の視線方向をそれぞれ考慮して選択する焦点検出点融合選択モードに設定される。この融合選択モードにおける融合選択アルゴリズムが本実施の形態の中心となるので、後に詳細に説明する。
【００６３】
図５（Ｂ）〜（Ｈ）は７つの焦点検出点から撮影レンズの焦点調節動作を行うための焦点検出点を、撮影者が予めある１つの焦点検出点に限定しておくための、焦点検出点手動選択モードにおける表示状態を表す。例えば図５（Ｂ）は焦点検出点２００に限定したものであり、図５（Ｃ）は焦点検出点２０１に限定したものである。
【００６４】
この焦点検出点手動選択モードによる焦点検出点選択は、焦点検出点を１点に絞っているために焦点検出時間が短くなり、合焦スピードのアップが図れると同時に、被写体がファインダ視野に対して一定の位置関係に固定されている場合においては、撮影者の意図する主被写体に正確にピント合わせを行うことができるといった効果がある。
【００６５】
逆に焦点検出点が１点しか存在しないために、被写体が動いたり、構図を少し変えただけで主被写体を焦点検出点から外してしまい、焦点検出が不可能となる欠点がある。さらに手動にて焦点検出点を切換えるのは手間がかかり、シャッタチャンスを逃す恐れもある。
【００６６】
そこで、撮影シーンと撮影者の意思に応じて、７つの焦点検出点から任意の１つをカメラが自動的に選択する、焦点検出点融合選択モードが有効となる。
【００６７】
図６は、図５（Ａ）の表示状態において撮影を行う焦点検出点融合選択モードに設定された場合の、融合選択アルゴリズムのフローチャートを示す。ここでの融合選択アルゴリズムは、撮影モードにおいて撮影者が被写体に対してカメラを構え、レリーズ釦４１の第１ストロークによってＯＮされるスイッチＳＷ−１をＯＮしたときに開始される。
【００６８】
スイッチＳＷ−１がＯＮされると、７つのラインセンサによって焦点検出が行われる（Ｓ１００）。このときそれぞれの焦点検出点に対応した被写体空間領域のデフォーカス量が検出される。ステップＳ１０１に移行し、このデフォーカス量を基準に被写体空間情報の点数化が行われる。
【００６９】
被写体空間情報の点数化とは、
【００７０】
【数式１】

【００７１】
で表されるように、デフォーカス量を基準に各焦点検出点に数値を割り振ることである。具体的には、図７の被写体空間情報の点数化動作を示すサブルーチンを用いて説明する。
【００７２】
図７のサブルーチンである被写体空間情報の点数化に移行（Ｓ１０１）すると、まずデフォーカス量を基準に被写体のグループ化を試みるサブルーチンＳ１０２へ進む。図８は焦点検出ラインによるグループ化を示すサブルーチンである。ステップＳ１１１において焦点検出に成功したライン数がカウントされ、焦点検出成功ラインが１ラインのみで、残り６ラインで出力エラーとなった場合、撮影レンズの焦点調節動作を行うための焦点検出点は、このラインに対応した焦点検出点に決定される（Ｓ１１２）。この場合、カメラはこの焦点検出点でしかピント合せができないので、被写体空間情報のみによって、この焦点検出点が選択されることになる。
【００７３】
複数のラインで焦点検出に成功した場合、ステップＳ１１３に移行する。この複数の焦点検出成功ラインの中で、検出されたデフォーカス量から、カメラから被写体の距離が最も近いと判断された検出ラインをラインＡと名付ける。次にステップＳ１１４において、ラインＡからカメラに対して無限遠側の中デフォーカス範囲内に焦点検出成功ラインが存在するか確認する。中デフォーカス範囲とは、予定結像面５の近傍において、光軸方向にピントのずれ量換算でＡ（ｍｍ）のデフォーカス量を表す。
【００７４】
すなわち、撮影レンズの焦点距離をｆ（ｍｍ）、予定結像面５からカメラに最も近い被写体までの距離をＬ（ｍｍ）とすると、カメラに最も近い被写体から無限遠側に略｛（Ｌ−ｆ）^２／ｆ^２ ｝×Ａ（ｍｍ）の範囲内に存在する被写体のグルーピングを目的とする。この中デフォーカス範囲内に焦点検出成功ラインが存在すれば、ステップＳ１１５に移り、存在するこれら全てのラインをラインＢと名付ける。次にステップＳ１１６に移行し、カメラから最も遠い被写体を捉えたラインＢからさらに、小デフォーカス範囲内に焦点検出ラインが存在するか確認する。このときの小デフォーカス範囲とは、予定結像面５の近傍において、光軸方向にピントのずれ量換算でＢ（ｍｍ）のデフォーカス量を表す。ただし、Ａ＞Ｂである。小デフォーカス範囲内に焦点検出成功ラインが存在すれば、それらをラインＣと名付ける。
【００７５】
すなわち、カメラから最も近い被写体に対し、中デフォーカス範囲内に被写体が存在する場合には、グルーピングの範囲をもう少し広げることを意図する。ラインＣが存在した場合には、ステップＳ１１８のおいて、ラインＡ，ラインＢ、ラインＣを主被写体グループとする。ステップＳ１１６で、小デフォーカス範囲内に焦点検出ラインが存在しなかった場合、すなわちラインＣが存在しない場合には、ステップＳ１１９において、ラインＡ，ラインＢを主被写体グループとする。ステップＳ１１４において、中デフォーカス範囲内に焦点検出成功ラインが存在しない場合には、ステップＳ１２０において、ラインＡをラインＯと名前を付け直し、２番目にカメラから近い被写体を捉えた焦点検出成功ラインをラインＡとする。
【００７６】
次に、ステップＳ１２１に移行し、ステップＳ１１４と同様に、ラインＡからカメラに対して無限遠側に中デフォーカス範囲内に焦点検出成功ラインが存在するか確認する。存在すればそれらのラインを全てラインＢと名付け（Ｓ１２２）、ステップＳ１２３に移り、ステップＳ１１６と同様にカメラから最も遠い被写体を捉えたラインＢからさらに、小デフォーカス範囲内に焦点検出ラインが存在するか確認する。存在すればステップＳ１２４で、それら全てのラインをラインＣと名付ける。この場合、ラインＯ，ラインＡ，ラインＢ，ラインＣを主被写体グループとする。
【００７７】
上記ステップＳ１２３で、小デフォーカス範囲内に焦点検出成功ラインが存在しない場合には、ラインＯ，ラインＡ，ラインＢを主被写体グループとする。また、上記ステップＳ１２１で、中デフォーカス範囲内に焦点検出成功ラインが存在しない場合には、ラインＯ，ラインＡを主被写体グループとする。
【００７８】
以上のように、カメラから最も近い被写体を基準に主被写体グループを定義する。
【００７９】
このようにして主被写体グループが定義されると、図７のステップＳ１０３に移行し、ラインＯ、Ａ、Ｂ，Ｃに対して特定の点数が与えられる。このときの点数化ルールを示すのが図９である。
【００８０】
本実施の形態においては、得られる各情報に関して、主被写体が存在するであろう焦点検出点には高得点を、そうでない焦点検出点には低得点を与えることにした。さらに、割り振る点数の範囲は任意に設定可能であるが、本実施の形態では、１点〜５点を各焦点検出点に割り振ることにした。
【００８１】
図９の点数化ルールでは、まずデフォーカス量検出によって被写体グループを捉えたラインに、ラインＯ，Ａ，Ｂ，Ｃのいずれが存在するかによって分類している。さらにグループに存在するラインＯ，Ａ，Ｂ，Ｃを捉えた焦点検出点の撮影画面上での配列が、互いに隣り合うか、もしくは離れた位置に存在するかによって分類している。こうして分類されたラインＯ，Ａ，Ｂ，Ｃに点数が与えられる。ただし、ラインＯ，Ａは図８のフローチャートによると、それぞれ１本もしくは０本しか存在しないが、ラインＢ，Ｃはグループ化によっては複数存在し得るので、とくに隣接および離散のいずれの可能性もあり、主被写体の構成に影響の大きい、複数のラインＢが存在する場合の為に＃Ｂを設けた。
【００８２】
一例を図１０を用いて説明する。
【００８３】
焦点検出点が不可能であった焦点検出点２０５は対象から外し、残りの焦点検出点に点数を割り振る。焦点検出点２０３がラインＡとなったとすると、まずこの焦点検出点に点数５がつく。ラインＢは焦点検出点２００と２０４に名付けられた。このとき焦点検出点２０３に隣り合う焦点検出点２０４には点数４が与えられるが、これらと離れた焦点検出点２００には点数５が与えられる。ラインＣと名付けられた焦点検出点２０６には点数４が与えられる。その他の焦点検出は可能であったが遠距離に存在する被写体を捉えた焦点検出点２０１，２０２には点数１が付けられる。このようにして、ラインに付けられた点数をステップＳ１０４で実際の全ての焦点検出点に被写体空間情報として対応させることができる。ちなみにこの場合には、
【００８４】
【数式２】

【００８５】
となる。
【００８６】
このようにして被写体空間情報を点数化した後、図７のステップＳ１０４を介して図６のメインルーチンへ戻り、ステップＳ２００へ進む。
【００８７】
図６のステップＳ２００では、本体に具備された姿勢センサ２７によってカメラの姿勢を検出する。これにより、撮影者がカメラを横位置に構えているのか縦位置に構えているのか、さらに縦位置であれば、カメラグリップ４０を天方向に向けた構え方なのか、もしくは地方向に向けた構え方なのかを検出できる。これら３つのタイプの構え方を、図１１（Ａ），（Ｂ），（Ｃ）の各状態とする。
【００８８】
カメラの姿勢検出が終わると、ステップＳ２０１へ移行し、焦点検出点情報の点数化が行われる。焦点検出点情報とは、カメラの構え方による撮影画面上の焦点検出点の相対的な配置状態と、それに対応する一般的な傾向としての、主被写体出現頻度を表す。すなわち、撮影画面に対し中央寄りもしくは上方に主被写体を置く構図が一般的に多いことを考慮したものであり、撮影画面中央寄りもしくは上方の焦点検出点を選ばれやすいように点数操作を行うものである。一方で、従来の篩方式にこの考えを適用したときに生じる、特定の焦点検出点が極端に選ばれにくいといった弊害を取り除くための操作でもある。
【００８９】
この焦点検出点情報の点数化とは、具体的には、
【００９０】
【数式３】

【００９１】
で表すこととし、カメラの状態図１１の（Ａ），（Ｂ），（Ｃ）それぞれに図１２で示す点数マップに従い、
【００９２】
【数式４】

【００９３】
と本実施の形態では定めることにする。
【００９４】
次に、ステップＳ３００に進み、撮影者の視線検出を行う。視線検出原理は従来例に示した通りであるので、ここでは省略する。
【００９５】
視線検出によって撮影者が撮影画面上どの点を観察しているのか、多少の誤差は含むものの、おおよその座標（Ｘｎ，Ｙｎ）が検出される。おおよその座標（Ｘｎ，Ｙｎ）が検出されると、ステップＳ３０１に移行し、視線情報の点数化を行う。
【００９６】
視線情報の点数化とは、
【００９７】
【数式５】

【００９８】
で表されるように、視線座標を基準に各焦点検出点に数値を割り振ることである。具体的には図１３の視線情報の点数化動作を示すサブルーチンを用いて説明する。
【００９９】
ステップＳ３０１でサブルーチンである視線情報の点数化に入ると、ステップＳ３１１に移行し、視線座標の撮影画面エリアへの対応付けが行われる。撮影画面エリアとは、図１４のように、撮影画面を１９の領域に分割した各エリアａ〜ｓであると本実施の形態では定義する。検出された視線座標（Ｘｎ，Ｙｎ）がどのエリアに属するかによって、７つの焦点検出点に与えられる点数を変化させることを目的とする。従ってステップＳ３１１では、具体的には、視線座標→撮影画面エリアの変換が行われる。
【０１００】
次に、撮影画面エリア→各焦点検出点への点数割り振りをステップＳ３１２で行う。本実施の形態では、図１５に示す点数化ルールを適用する。これは、図１４の各エリアａ〜ｓに対し、検出視線座標がその領域に属したとき、カメラは７つの焦点検出点のうち、どの焦点検出点で撮影レンズの焦点調節動作を行うのが妥当であるのかを基準に、高い点数から順に低い点数までを割り振ったものである。例えば、エリアａに視線座標（Ｘｎ，Ｙｎ）が検出されると、エリアａが対象とする焦点検出点はエリアａに最も近い焦点検出点２０４のみであり、この焦点検出点に点数５が与えられ、その他の焦点検出点には点数１が与えられる。
【０１０１】
また、エリアｏに検出されると、エリアｏに含まれる焦点検出点２０５にもっとも高い点数５が与えられ、焦点検出点２０５に隣接する焦点検出点２０２に点数４が、次に近い焦点検出点２０１，２０３に点数３が与えられ、エリアｏの対象外である焦点検出点２００，２０４，２０６には点数１が与えられる。これは、検出視線座標には誤差が含まれていることを前提としているため、たとえエリア内に焦点検出点が存在していても、その点のみを対象とはせず、少し広い範囲での焦点検出点の全てを対象として、最終的に撮影レンズの焦点調節動作を行うための焦点検出点として選択される可能性を持たせておくためである。
【０１０２】
以上の操作により視線情報の点数化が終わると、図６のメインルーチンに戻り、ステップＳ４００の情報の融合／比較演算に移行する。ここでは、これまでのルーチンにより数値化された被写体空間情報および焦点検出点情報および視線情報を融合し、７つの焦点検出点の間で比較を行う。
【０１０３】
各焦点検出点の合計得点を、
【０１０４】
【数式６】

【０１０５】
で計算することにする。
【０１０６】
本実施の形態では、ｄ_i ，ｐ_i ，ｅ_i の全ての点数化に対し点数０から５の範囲で与えている。すなわちどの情報も均等に取り扱っていることになる。そこで各情報間の重み付け係数として、α, β, γを用意する。これはどの情報を重視するかによって自由に設定可能な係数である。例えば、視線情報を補助情報として、被写体空間情報や焦点検出点情報を主たる情報として取り扱うならば、γを小さくしてα，βを大きくすれば良いし、逆に視線情報を重視するならばγを大きくすれば良い。
【０１０７】
このように重み付け係数を介して合計された各焦点検出点の合計得点を比較する。本実施の形態では、主被写体が存在するであろう焦点検出点には高得点を、そうでない焦点検出点には低い得点を与え、さらに重視する情報には重み付け係数で高い比率を与えてきたので、最終的にどの焦点検出点で撮影レンズの焦点調節動作を行うかは、合計得点の最も高い焦点検出点を選択すれば良い（ステップＳ５００）。
【０１０８】
以上のプロセスにより、最終的に撮影レンズの焦点調節動作を行うための焦点検出点が１つ選択された。１つの焦点検出点が選択されると、その焦点検出点をスーパーインポーズ表示で撮影者に知らしめ、公知の撮影動作が実行される。
【０１０９】
以上の実施の形態によれば、カメラに具備されるセンサ群（ラインセンサ群６ｆ、イメージセンサ１４、姿勢センサ２７）から得られる各種の情報を、焦点検出点を基準として数値化し、最終的に合計して得られる数値の多寡により、撮影レンズの焦点調節動作を行うための焦点検出点を選択する方式であるため、複数存在する焦点検出点のうち特定の焦点検出点が選択されにくかったり、被写体やカメラの構え方のわずかな変化によって大きく異なるピント結果になってしまうといった課題が解決される。
【０１１０】
具体的には、複数の焦点検出点によって検出されるデフォーカス量や被写体までの距離による被写体空間情報、およびカメラの構え方による、主被写体出現の頻度を表す焦点検出点情報、および撮影者が撮影画面上の注視座標を略表す視線情報のうち、少なくとも２つを用いることとしている。また、各情報間の足し合わせを行う際に、どの情報カテゴリーを優先するかによって、足し合わせの比率を変化させるようにしている。又、焦点検出点で捉えた、カメラに最も近接する被写体から一定距離に存在する被写体を被写体グループとし、このグループを捉えた焦点検出点に対して、近接する被写体を捉えた焦点検出点から順に点数を付与したり、前記被写体グループ内に、空間的に離れた被写体が存在すると思われる場合には、主被写体である可能性を同等とする点数を付与するようにしている。又、撮影画面を複数の領域に分割し、視線座標がある領域に計算された場合、どの焦点検出点において撮影レンズの焦点調節動作をさせるのが妥当かを基準に、全ての焦点検出点に対して点数を付与した点数化マップを用意している。
【０１１１】
また、従来の自動選択アルゴリズムでは、撮影者の意思を情報として取り込んでいなかったため、思いもよらない被写体にピントが合わせられたり、一方で、撮影者の視線によって焦点検出点を選択する視線選択方式では、種々の理由から正確な撮影画面上の視線座標は検出できないために、必ずしも撮影者が意図していた座標と一致しなかったりしていた。しかし本実施の形態によれば、特定の情報に偏ることなく、各情報の数値化操作によって、互いの情報の不足する部分を補い、総合的に主被写体の存在する可能性が最も高い焦点検出点を選択するため、従来のアルゴリズムでは成し得なかった主被写体の捕捉率を実現することが可能となった。
【０１１２】
（変形例）
情報のカテゴリーとして、上記の実施の形態では、被写体空間情報および焦点検出点情報および視線情報の３つを対象としたが、最終的に撮影レンズの焦点調節動作を行うための焦点検出点を選択するための情報としては、このうち任意の２つのみを用いても良い。
【０１１３】
また同様に、対象とする情報のカテゴリーは、この３つに絞られるものではなく、焦点検出点を選択するために有意な情報であれば、カテゴリーの対象としても良い。
【０１１４】
また、焦点検出点を７つとしたが、この点数に限るものではない。
【０１１５】
また、情報の点数化の設定点数範囲を０〜５の整数値を用いたが、この範囲は任意の実数値を設定しても良い。また、被写体が存在すると思われる焦点検出点ほど高得点を与えたが、逆にそのような焦点検出点に低い点数を与え、最終的に最も低い得点が付与された焦点検出点を選択されるようにしてもよい。
【０１１６】
本実施の形態で用いた各情報の点数化マップは、実情に即して任意に変更可能である。
【０１１７】
また、視線情報における撮影画面の領域分割数を１９とし、図１４のように設定したが、この境界の分割ラインと領域分割数は自由に設定可能である。
【０１１８】
また、本実施の形態での点数化の順序は、被写体空間情報→焦点検出点情報→視線情報の順であったが、この順序は任意に設定可能である。
【０１１９】
【発明の効果】
以上説明したように、本発明によれば、複数の焦点検出点のうち特定の焦点検出点が選択されにくかったり、被写体やカメラの構え方のわずかな変化によって大きくピントがずれてしまうといったことを無くすことができる自動焦点カメラを提供できるものである。
【図面の簡単な説明】
【図１】本発明の実施の一形態に係る一眼レフカメラの要部概略図である。
【図２】図１の一眼レフカメラの要部外観図である。
【図３】図１のファインダ視野図である。
【図４】図１の一眼レフカメラの電気的構成を示すブロック図である。
【図５】図３のファインダ視野内の表示状態を説明する為の図である。
【図６】本発明の実施の一形態における動作を示すフローチャートである。
【図７】図６内のサブルーチンを示すフローチャートである。
【図８】同じく図６内のサブルーチンを示すフローチャートである。
【図９】本発明の実施の一形態における点数化マップ図である。
【図１０】本発明の実施の一形態における点数化例を示す図である。
【図１１】一般的なカメラの構え方について説明する為の図である。
【図１２】本発明の実施の一形態における点数化マップ図である。
【図１３】図６内のサブルーチンを示すフローチャートである。
【図１４】本発明の実施の一形態における撮影画面分割を示す図である。
【図１５】本発明の実施の一形態における点数化マップ図である。
【図１６】従来例のファンダ視野図である。
【図１７】従来例の自動選択アルゴリズムを示すフローチャートである。
【図１８】一般的な視線検出装置の要部概略図である。
【図１９】眼球像の要部概略図である。
【図２０】撮影シーンの一例を示す図である。
【図２１】同じく査定シーンの他の例を示す図である。
【符号の説明】
１ 撮影レンズ
６ 焦点検出装置
６ｆ ラインセンサ群
１３ 赤外発光ダイオード（ＩＲＥＤ）
１４ イメージセンサ（ＣＣＤ−ＥＹＥ）
２４ ファインダ内ＬＣＤ
２７ 姿勢センサ
４１ レリーズ釦
４６ 焦点検出点選択釦
１００ ＣＰＵ
１０１ 視線検出回路
１０３ 焦点検出回路
１１０ 焦点調節回路
２００〜２０６ 焦点検出点[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of an autofocus camera having a plurality of focus detection points on a photographing screen.
[0002]
[Prior art]
As one type of focus detection device, the exit pupil of the photographing lens is divided by the optical system of the focus detection system, and two subject images formed by the light flux that has passed through each pupil region are received by the photoelectric conversion element array. A method for detecting the focus state of a photographic lens by detecting the amount of displacement (displacement) of the relative positions of two subject images is widely known. In this way, the relative position displacement is obtained, and the defocus amount of the photographing lens, so-called defocus amount, is detected. When the detection method for detecting the defocus amount is used, the pair of sensors extract only the luminance distribution of a specific area in the subject space, and therefore the defocus amount is calculated for a subject that does not have the luminance distribution in that area. I can't. Therefore, a method that enables focus detection for a larger number of subjects by preparing multiple sensor pairs and corresponding focus optical systems and extracting the luminance distribution of the multiple subject areas has been disclosed. 59-28886, JP-A-62-212611 and the like.
[0003]
The camera grasps the state of the subject space, that is, the relative position of the subject existing in the space corresponding to the focus detection point, based on the defocus amount detected from the plurality of focus detection points (meaning a region where focus detection is performed). I can do things. The plurality of focus detection points for performing focus detection are, for example, 200 to 206 in FIG. 16 (actually, focus detection point marks are shown. As A method for obtaining a final defocus amount from a plurality of focus detection mechanisms corresponding to the plurality of focus detection points, that is, a focus adjustment operation of the photographing lens. As a method for determining a focus detection point for performing the focusing, a near point priority method in which the central focus detection point is weighted, and a grouping method in which subjects whose relative positions are close to each other are grouped are known. .
[0004]
An example is shown based on the focus detection point automatic selection algorithm of Japanese Patent Application No. 11-062551, which is a proposal by the present applicant.
[0005]
FIG. 17 is a flowchart of an automatic focus detection point selection algorithm that employs the near point priority and grouping method. The line in the figure indicates a line sensor composed of a photoelectric conversion element array corresponding to each focus detection point. Since the actual detection is performed by the output of the line sensor, description will be made with reference to seven lines corresponding to the focus detection points 200 to 206.
[0006]
When automatic focus detection point selection is started, focus detection is performed by the seven line sensors. At this time, the luminance distribution of the area is extracted from the subject corresponding to each focus detection point. If there is no luminance distribution in the subject area, the line output becomes an error.
[0007]
First, in step S01, when the luminance distribution is successfully extracted, that is, the number of lines for which focus detection is successful is counted, and there is only one focus detection success line and an output error occurs in the remaining six lines, the focus of the photographing lens A focus detection point for performing the adjustment operation is determined as a focus detection point corresponding to this line (S02).
[0008]
If focus detection is successful for a plurality of lines, the process proceeds to step S03. Among the plurality of focus detection success lines, a detection line that is determined to be the closest to the subject from the camera based on the detected defocus amount is named line A. Next, in step S04, it is confirmed whether a focus detection success line exists in the middle defocus range from the line A to the camera at infinity. The middle defocus range represents a defocus amount of a (mm) in the optical axis direction in the vicinity of the planned imaging plane.
[0009]
That is, if the focal length of the photographic lens is f (mm) and the distance from the planned imaging plane to the subject closest to the camera is L (mm), the object closest to the camera is approximately {(L−f ) ² / F ² } The purpose is to group subjects existing within a range of xa (mm). If a = 2 (mm), for example, when a photographic lens with a focal length of 50 (mm) is attached, and the subject closest to the camera is located 2.55 (m) from the image plane, The subject grouping is performed in the range of 5 (m) from the position to infinity.
[0010]
If a focus detection success line exists in the defocus range, the process moves to step S05, and all these existing lines are named line B. Next, the process proceeds to step S06, where it is confirmed whether a focus detection line exists within the small defocus range from the line B that captures the subject farthest from the camera. The small defocus range at this time represents a defocus amount of b (mm) in the optical axis direction in the vicinity of the planned imaging plane. However, a> b. If there are focus detection success lines in the small defocus range, they are named line C.
[0011]
That is, when the subject is within the middle defocus range with respect to the subject closest to the camera, the grouping range is intended to be expanded a little more. If line C exists, in step S08, line A, line B, and line C are set as the main subject group. If no focus detection line exists in the small defocus range in step S06, that is, if no line C exists, line A and line B are set as main subject groups in step S09.
[0012]
In step S04, if there is no focus detection success line in the middle defocus range, in step S10, the line A is renamed as line O, and the focus detection succeeds in capturing the subject closest to the camera. Let line A be line A.
[0013]
Next, the process proceeds to step S11, and as in step S04, it is confirmed whether a focus detection success line exists in the middle defocus range from the line A to the infinity side with respect to the camera. If they exist, all those lines are named line B (S12), and the process proceeds to step S13. As in step S06, there is a focus detection line within the small defocus range from line B that captures the subject farthest from the camera. Confirm whether to do. If it exists, all these lines are named line C in step S14. In this case, line O, line A, line B, and line C are set as the main subject group. If the focus detection success line does not exist within the small defocus range in step S13, line O, line A, and line B are set as the main subject group. In step S11, when there is no focus detection success line in the middle defocus range, the lines O and A are set as the main subject group.
[0014]
As described above, the main subject group is defined based on the subject closest to the camera.
[0015]
A line corresponding to the focus detection point close to the center detection point is extracted from the main subject group defined in this manner (S18). If there is one line extracted at this time (S21), that line is selected. If there are two or more lines, the line that detects the object closest to the camera is selected, and the focus detection corresponding to the selected line is detected. It is determined that the focus adjustment operation of the taking lens is performed at the point.
[0016]
With the above algorithm, a focus detection point where the main subject is supposed to exist is extracted from a plurality of focus detection points, and the focus adjustment operation of the photographing lens is performed at the focus detection point.
[0017]
On the other hand, cameras with a line-of-sight detection function for detecting which direction on the shooting screen the photographer is gazing at are widely provided. In Japanese Patent Laid-Open No. 2-264632, eye gaze detection is performed to irradiate a photographer's eyeball with infrared light, and to use the cornea reflection image by the reflected light from the cornea of the eyeball and the imaging position of the pupil. An apparatus is disclosed.
[0018]
FIG. 18 is a diagram illustrating the principle of a known gaze detection method.
[0019]
In the figure, reference numerals 13a and 13b denote light sources such as light emitting diodes that emit insensitive infrared light to the user, and the light sources 13a and 13b are substantially symmetrical in the x direction with respect to the optical axis of the light receiving lens 12. Furthermore, it arrange | positions so that a user's eyeball 15 may be illuminated from the downward direction (position offset in the y direction). Part of the illumination light reflected by the eyeball 15 is condensed on the image sensor 14 via the light receiving lens 12. 16 is a cornea, 17 is an iris.
[0020]
FIG. 19A is a schematic diagram of an eyeball image projected on the image sensor 14, and FIG. 19B is a diagram showing an intensity distribution of a signal from the output line of the image sensor 14.
[0021]
Hereinafter, the gaze detection method will be described with reference to each of the above-described drawings.
[0022]
The infrared light emitted from the light source 13b irradiates the cornea 16 of the user's eyeball 15. At this time, the reflected cornea image d (virtual image) formed by a part of the infrared light reflected by the surface of the cornea 16 is collected by the light receiving lens 12 and formed at a position d ′ on the image sensor 14. Similarly, the infrared light emitted from the light source 13 a irradiates the cornea 16 of the eyeball 15. At this time, the cornea reflection image e formed by a part of the infrared light reflected by the surface of the cornea 16 is condensed by the light receiving lens 12 and formed at a position e ′ on the image sensor 14.
[0023]
Further, the light beams from the ends a and b of the iris 17 form images of the ends a and b at positions a ′ and b ′ on the image sensor 14 via the light receiving lens 12. When the rotation angle θ of the optical axis of the eyeball 15 with respect to the optical axis of the light receiving lens 12 is small, if the x coordinates of the ends a and b of the iris 17 are xa and xb, the coordinate x of the center position c of the pupil 19 is
xc≈ (xa + xb) / 2
It is expressed.
[0024]
Further, the x coordinate of the midpoint of the cornea reflection images d and e and the x coordinate xo of the center of curvature o of the cornea 16 substantially coincide. Therefore, the x-coordinates of the corneal reflection image generation positions d and e are xd and xe, the standard distance from the center of curvature o of the cornea 16 to the center c of the pupil 19 is Loc, and a coefficient that considers individual differences with respect to the distance Loc. Is A1, the rotation angle θ of the optical axis 15a of the eyeball 15 is
A1 × Loc × sin θ≈xc− (xd + xe) / 2 (1)
Is substantially satisfied. For this reason, as shown in FIG. 19A, the optical axis of the eyeball 15 is detected by detecting the position of each feature point (corneal reflection image and the center of the pupil) of the eyeball 15 projected on the image sensor 14. The rotation angle θ of 15a can be obtained.
[0025]
The rotation angle of the optical axis 15a of the eyeball 15 is obtained from the equation (1).
β × A1 × Loc × sin θ≈ (xa ′ + xb ′) / 2
− (Xd ′ + xe ′) / 2 (2)
It can be rewritten. However, β is a magnification determined by the position of the eyeball 15 with respect to the light receiving lens 12 and is substantially obtained as a function of the interval | xd′−xe ′ |
[0026]
The rotation angle θ of the optical axis of the eyeball 15 is
θ≈arcsin {(xc′−xf ′) / (β × A1 × Loc)} (3)
It can be rewritten as However,
xc′≈ (xa ′ + xb ′) / 2
xf′≈ (xd ′ + xe ′) / 2
It is.
[0027]
By the way, since the optical axis 15a of the user's eyeball 15 does not coincide with the visual axis, when the horizontal rotation angle θ of the optical axis of the user's eyeball is calculated, the angle correction between the optical axis and the visual axis is corrected. By doing so, the user's horizontal line of sight θH is obtained. If a coefficient (line-of-sight correction coefficient) that takes into account individual differences with respect to the correction angle δ between the optical axis 15a of the eyeball 15 and the visual axis is B1, the visual line θH in the horizontal direction of the user is
θH = θ ± (B1 × δ) (4)
Is required. Here, when the rotation angle to the right with respect to the user is positive, the sign ± is selected when the user's eyes except the observation apparatus (finder system) are left eyes, and when the right eye is −, signs are selected.
[0028]
Further, in the figure, an example in which the user's eyeball rotates in the zx plane (horizontal plane) is shown, but even when the user's eyeball rotates in the yz plane (vertical plane). Similarly, it can be detected. However, since the vertical component of the user's line of sight coincides with the vertical component θ ′ of the optical axis 15a of the eyeball 15, the vertical line of sight θV is
θV = θ ′
It becomes.
[0029]
Further, when a single-lens reflex camera is used as the optical device, the position (xn, yn) on the focusing screen that the user is viewing from the line-of-sight data θH, θV is

Is required. Here, m is a constant determined by the finder optical system of the camera.
Here, there are two coefficients A1 and B1 for correcting the individual differences in the line of sight. For example, the user sees two targets at different positions, and is calculated according to the position of the index and the above equation (5). The coefficients A1 and B1 can be obtained by matching the positions of the fixed viewpoints.
[0030]
In this way, by detecting where the photographer is looking at the photographing screen, the focus detection point present at the position closest to the detected coordinates (xn, yn) is used to adjust the focus of the photographing lens. It can be determined as a focus detection point for performing.
[0031]
[Problems to be solved by the invention]
In the conventional automatic selection algorithm that determines the focus detection point for the focus adjustment operation of the photographic lens based on the subject space information obtained from the focus detection point, all focus detection points are obtained by a series of grouping methods. A part of the focus detection points are extracted, and the target focus detection points are narrowed down by the relative position of the focus detection points on the shooting screen, and finally one focus detection point is selected by the principle of near point priority. ing. That is, the focus detection points existing on the photographing screen are sieved by each piece of information, and if even one of the pieces of information does not satisfy the condition, the focal point for finally performing the focus adjustment operation of the photographing lens. The system is not selected as a detection point.
[0032]
In this algorithm, considering the increase in the number of focus detection points on the shooting screen, even when two conditions are applied to adjacent two focus detection points that are close to each other, even if there are subtle differences, they are divided by a sieve. Result in extremely different results.
[0033]
Therefore, the focus detection point extraction method based on such a sieving method makes it difficult to select a specific focus detection point, or obtains a significantly different focus result depending on a slight change in the subject or the way the camera is held.
[0034]
Further, in the automatic selection algorithm, it is unavoidable that the camera predicts the intention of the photographer, so that a deviation from the focus detection point intended by the photographer occurs depending on the photographing scene. For example, as shown in FIG. 20, when there are two or more candidates to be main subjects on the shooting screen, according to the automatic selection algorithm, the front flower is focused. However, in reality, the photographer may have wanted to blur the front and focus on the back flower as the main subject.
[0035]
Furthermore, in the scene as shown in FIG. 21, in the front plant and the car near the center, the automatic selection algorithm focuses on the front plant from the principle of near point priority. Even for objects that can be easily determined to be difficult to become the main subject if the photographer observes, the automatic selection algorithm uniformly predicts the main subject from the defocus amount that is the subject information, so as long as there is no intention information of the photographer, Such a problem inevitably remains.
[0036]
On the other hand, by observing the eyeball image of the photographer, the gaze selection algorithm that detects the gaze direction and determines the focus detection point for performing the focus adjustment operation of the photographic lens, the calculated coordinates on the photographic screen are not necessarily There is a problem that it does not match the coordinates intended by the photographer. Many causes have been confirmed, but as a typical example, eye movements continue unconsciously or the outside world may be observed with peripheral vision. It is not always possible to detect whether or not you are observing the eye, the eyelids are trapped in the pupil, or the eyeball image is defective due to the disturbance of the image caused by ambient light, and changes with every shooting Examples include points depending on how the camera is held, points due to changes in pupil diameter due to changes in ambient illumination, and changes in rotation angle.
[0037]
As described above, both the conventional automatic selection algorithm and the line-of-sight selection algorithm have problems, and the photographer has not always succeeded in selecting the desired focus detection point.
[0038]
(Object of invention)
An object of the present invention is to provide an automatic focus that can eliminate the difficulty of selecting a specific focus detection point from among a plurality of focus detection points, or a large focus shift due to a slight change in the way the subject or camera is held. Is to provide a camera.
[0039]
[Means for Solving the Problems]
In order to achieve the above object, the present invention selects one focus detection point from among a plurality of focus detection points on a shooting screen, and adjusts the focus of the shooting lens based on focus detection information obtained at the focus detection point. In an autofocus camera having a focusing means for performing an operation, First detection means for detecting a defocus amount for each focus detection point When, A second detection means for detecting an attitude; and one focus detection point closest to the defocus amount corresponding to the plurality of focus detection points detected by the first detection means and the one focus detection point. In addition, the number of focus detection points indicating the defocus amount on the infinity side is not discrete at the one focus detection point, and a score higher than the number of focus detection points indicating the defocus amount on the infinity side is given. And based on the posture detected by the second detection means Scoring means for assigning a score to each of the plurality of focus detection points according to a predetermined scoring map, and the focusing means by the scoring means, Grant The focus adjustment operation of the photographic lens is performed by selecting one of the plurality of focus detection points according to the numerical value obtained by summing the scores of the plurality of focus detection points for each focus detection point. The auto focus camera to be used.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on illustrated embodiments.
[0041]
FIG. 1 is a main part schematic diagram showing an embodiment when the present invention is applied to a single-lens reflex camera.
[0042]
In FIG. 1, reference numeral 1 denotes a photographic lens, which is shown as two lenses for convenience, but actually includes a larger number of lenses. Reference numeral 2 denotes a main mirror, which is obliquely disposed on the photographing optical path or moved away depending on the observation state of the subject image by the finder system and the photographing state of the subject image. Reference numeral 3 denotes a sub-mirror that reflects the light beam transmitted through the main mirror 2 toward a focus detection device 6 described below below the camera body. Reference numeral 4 denotes a shutter, and 5 denotes a photosensitive member, which is a silver salt film or a solid-state imaging device such as a CCD or MOS type. Reference numeral 6 denotes a focus detection device, which includes a field lens 6a, reflection mirrors 6b and 6c, a secondary imaging lens 6d, an aperture 6e, a line sensor 6f composed of a plurality of CCDs, and the like disposed in the vicinity of the imaging surface. .
[0043]
The focus detection device 6 in this embodiment performs focus detection by a well-known phase difference method, and, as shown in FIG. 3, is a plurality of regions 200 to 206 in the photographing screen (in the viewfinder field). Using (seven places) as focus detection points, the focus detection points can be detected.
Reference numeral 7 denotes a focusing plate arranged on the planned imaging plane of the taking lens 1, 8 denotes a finder optical path changing pentaprism, and 9 and 10 denote an imaging lens and a photometric sensor for measuring subject brightness in the observation screen. is there. The imaging lens 9 has a conjugate relationship between the focusing plate 7 and the photometric sensor 10 via the reflected light path in the pentaprism 8.
[0044]
An eyepiece lens 11 having a light splitter 11 a is arranged behind the pentaprism 8 and is used for observing the focusing screen 7 by the user's eye 15. The light splitter 11a is composed of, for example, a dichroic mirror that transmits visible light and reflects infrared light. Reference numeral 12 denotes a light receiving lens, and reference numeral 14 denotes an image sensor in which a photoelectric conversion element array such as a CCD is two-dimensionally arranged. The image sensor is conjugated with the vicinity of the pupil of the user's eyeball 15 at a predetermined position with respect to the light receiving lens 12. ing. Reference numerals 13a to 13f denote infrared light emitting diodes which are illumination light sources.
[0045]
Reference numeral 21 denotes a high-intensity superimposing LED that can be seen even in a bright subject. Light emitted from the LED is reflected by the main mirror 2 via the projection prism 22 and is provided on the display unit of the focusing screen 7. The light is bent in the vertical direction by the prism array 7 a, and reaches the user's eye 15 through the pentaprism 8 and the eyepiece 11.
[0046]
Therefore, the microprism array 7a is formed in a frame shape at a plurality of positions corresponding to the focus detection points on the focus plate 7, and is formed into seven superimposing LEDs 21 (each of which is LED-L1, LED- L2, LED-C, LED-R1, LED-R2, LED-U, and LED-D). Accordingly, as described above, in the finder field shown in FIG. 3, each focus detection point 200, 201, 202, 203, 204, 205, 206 shines in the finder field, and the focus detection point can be displayed. Is. Reference numeral 23 denotes a field mask for forming a finder field area. Reference numeral 24 denotes an in-finder LCD for displaying photographing information outside the finder field, which is illuminated by an illumination LED (F-LED) 25. The light transmitted through the in-viewfinder LCD 24 is guided out of the viewfinder field by the triangular prism 26 and allows the user to visually recognize various types of photographing information as shown in FIG.
[0047]
Reference numeral 27 denotes a known posture sensor for detecting the posture of the camera, and this output detects information such as whether the camera is held in the vertical position or the horizontal position.
[0048]
Reference numeral 31 denotes an aperture provided in the photographing lens 1, and reference numeral 32 denotes an aperture drive circuit described later. 111 , A lens driving motor, and a lens driving member including a driving gear. Reference numeral 35 denotes a photocoupler, which detects the rotation of the pulse plate 36 interlocked with the lens driving member 34. Focus adjustment circuit 110 To tell. Focus adjustment circuit 110 The lens driving motor 33 is driven by a predetermined amount based on this information and the lens driving amount information from the camera side, and the photographing lens 1 is moved to the in-focus position. Reference numeral 37 denotes a mount contact serving as an interface between a known camera and a lens.
[0049]
2A and 2B are schematic views of the upper surface and the rear surface of a single-lens reflex camera having the above-described configuration. In FIG. 2, 41 is a release button, and 42 is a monitor LCD as an external monitor display device. Reference numeral 44 denotes a mode dial for selecting a shooting mode or the like.
[0050]
Reference numeral 45 denotes a rotary electronic dial for setting various set values by combining with other operation members and modes. Reference numeral 46 denotes a focus detection point selection button for selecting whether to perform focus detection using any one of a plurality of focus detection points 200 to 206 in the screen, which is directly related to the features of the present invention. This operation will be described in detail later. Further, the other operation members shown in FIG. 2 are not particularly related to the present invention, and thus the description thereof is omitted.
[0051]
FIG. 4 is an electric circuit diagram built in the single-lens reflex camera having the above-described configuration, and the same parts as those in FIG.
[0052]
A microcomputer (hereinafter referred to as CPU) 100 built in the camera body includes a line-of-sight detection circuit 101, a photometry circuit 102, an automatic focus detection circuit 103, a signal input circuit 104, an LCD drive circuit 105, an LED drive circuit 106, and an IRED. A drive circuit 107, a shutter control circuit 108, and a motor control circuit 109 are connected. Further, signals are transmitted to the focus adjustment circuit 110 and the aperture driving circuit 111 arranged in the photographing lens 1 through the mount contact 37 shown in FIG.
[0053]
The EEPROM 100a attached to the CPU 100 has a storage function of line-of-sight correction data for correcting individual differences in line-of-sight as storage means. The line-of-sight detection circuit 101 A / D-converts the eyeball image signal from the image sensor 14 (CCD-EYE) and transmits this image information to the CPU 100. As will be described later, the CPU 100 extracts each feature point of the eyeball image necessary for eye-gaze detection according to a predetermined algorithm, and further calculates the user's eye-gaze from the position of each feature point.
[0054]
The line sensor 6f includes seven sets of line sensors CCD-L2, CCD-L1, CCD-C, CCD-R1, and CCD-R2 corresponding to the seven focus detection points 200 to 206 in the finder field shown in FIG. , CCD-U, CCD-D, a known CCD line sensor. The automatic focus detection circuit 103 A / D converts the voltage obtained from the line sensor 6 f and sends it to the CPU 100.
[0055]
SW1 is turned on by the first stroke of the release button 41, a switch for starting photometry, AF, line-of-sight detection operation, etc., SW2 is a release switch that is turned on by the second stroke of the release button, and SW-AEL is 43 AE lock. The AE lock switches SW-DIAL1 and SW-DIAL2 that are turned on by pressing a button are dial switches provided in the 45 electronic dial, which are input to the up / down counter of the signal input circuit 104 and rotate the electronic dial. Clicks are counted here.
[0056]
The LCD driving circuit 105 has a known configuration for driving the LCD in the finder 24 and the LCD 42 for monitoring, and monitors the display of the aperture value, shutter time, set photographing mode, etc. in accordance with signals from the CPU 100. Can be displayed on both the LCD 42 and the in-finder LCD 24 simultaneously.
[0057]
The LED driving circuit 106 controls lighting and blinking of the illumination LED (F-LED) 25 and the superimposing LED 21. The IRED drive circuit 107 selectively turns on the infrared light emitting diodes (IRED1 to 6) 13a to 13f according to the situation.
[0058]
When energized, the shutter control circuit 108 controls the magnet MG-1 that travels the front curtain and the magnet MG-2 that travels the rear curtain, and exposes the photosensitive member to a predetermined amount of light. The motor control circuit 109 controls the motor M1 that winds and rewinds the film and the motor M2 that charges the main mirror 2 and the shutter 4.
[0059]
These shutter control circuit 108 and motor control circuit 109 operate a series of camera release sequences.
[0060]
Next, a method for selecting a focus detection point used for actually performing the focus adjustment operation of the photographing lens from a plurality of focus detection points in the present embodiment will be described.
[0061]
5 (A) to 5 (H), (A) → (B) →... → (H) each time the electronic dial 45 is clicked and rotated clockwise while depressing the focus detection point selection button 46, the super in the viewfinder. The impose display changes sequentially, and the state of returning to (A) is shown by rotating it one more click. When the electronic dial 45 is rotated counterclockwise, the display is performed in the order opposite to the arrow in FIG.
[0062]
In the display state of FIG. 5A, when the operation shifts to the operation of another operation member, the focus detection point for the camera to perform the focus adjustment operation of the photographing lens from the seven focus detection points 200 to 206 is set to each focus detection point. The focus detection point fusion selection mode is selected in consideration of the defocus amount state, the relative position of the focus detection point, and the line of sight of the photographer. The fusion selection algorithm in this fusion selection mode is the center of this embodiment, and will be described in detail later.
[0063]
FIGS. 5B to 5H show the focus for limiting the focus detection point for performing the focus adjustment operation of the photographing lens from the seven focus detection points to one focus detection point in advance by the photographer. The display state in the detection point manual selection mode is shown. For example, FIG. 5B is limited to the focus detection point 200, and FIG. 5C is limited to the focus detection point 201.
[0064]
The focus detection point selection in this focus detection point manual selection mode is because the focus detection point is reduced to one point, the focus detection time is shortened, the focusing speed can be increased, and at the same time the subject is in the viewfinder field of view. When the positional relationship is fixed, there is an effect that the main subject intended by the photographer can be accurately focused.
[0065]
On the other hand, since there is only one focus detection point, there is a drawback that the main subject is removed from the focus detection point even if the subject moves or the composition is slightly changed, and focus detection is impossible. Further, manually switching the focus detection point is time-consuming and may miss a photo opportunity.
[0066]
Therefore, the focus detection point fusion selection mode in which the camera automatically selects any one of the seven focus detection points according to the shooting scene and the photographer's intention is effective.
[0067]
FIG. 6 shows a flowchart of the fusion selection algorithm when the focus detection point fusion selection mode for performing photographing in the display state of FIG. 5A is set. The fusion selection algorithm here is started when the photographer holds the camera on the subject in the shooting mode and turns on the switch SW-1 that is turned on by the first stroke of the release button 41.
[0068]
When the switch SW-1 is turned on, focus detection is performed by the seven line sensors (S100). At this time, the defocus amount of the subject space area corresponding to each focus detection point is detected. In step S101, the subject space information is scored based on the defocus amount.
[0069]
What is scoring of subject space information?
[0070]
[Formula 1]

[0071]
In other words, a numerical value is assigned to each focus detection point on the basis of the defocus amount. Specifically, a description will be given using a subroutine showing the operation of scoring the subject space information in FIG.
[0072]
When the process shifts to scoring of subject space information, which is the subroutine of FIG. 7 (S101), the process proceeds to a subroutine S102 that attempts to group subjects based on the defocus amount. FIG. 8 is a subroutine showing grouping by focus detection lines. When the number of lines successfully detected in step S111 is counted, and there is only one focus detection success line and an output error occurs in the remaining six lines, the focus detection point for performing the focus adjustment operation of the photographing lens is The focus detection point corresponding to this line is determined (S112). In this case, since the camera can focus only at this focus detection point, this focus detection point is selected only by subject space information.
[0073]
If focus detection is successful for a plurality of lines, the process proceeds to step S113. Among the plurality of focus detection success lines, a detection line that is determined to be the closest to the subject from the camera based on the detected defocus amount is named line A. Next, in step S114, it is confirmed whether a focus detection success line exists in the middle defocus range on the infinity side from the line A to the camera. The middle defocus range represents the defocus amount of A (mm) in the vicinity of the planned imaging plane 5 in terms of the amount of focus shift in the optical axis direction.
[0074]
That is, if the focal length of the photographic lens is f (mm) and the distance from the planned imaging plane 5 to the subject closest to the camera is L (mm), the object closest to the camera is approximately {(L− f) ² / F ² } The purpose is to group subjects existing within the range of × A (mm). If a focus detection success line exists in the defocus range, the process moves to step S115, and all these existing lines are named line B. Next, the process proceeds to step S116, where it is confirmed whether a focus detection line exists within the small defocus range from the line B that captures the subject farthest from the camera. The small defocus range at this time is the planned imaging plane Of 5 In the vicinity, the defocus amount of B (mm) is expressed in terms of the amount of focus shift in the optical axis direction. However, A> B. If there are focus detection success lines in the small defocus range, they are named line C.
[0075]
That is, when the subject is within the middle defocus range with respect to the subject closest to the camera, the grouping range is intended to be expanded a little more. If line C exists, in step S118, line A, line B, and line C are set as the main subject group. If the focus detection line does not exist in the small defocus range in step S116, that is, if the line C does not exist, line A and line B are set as the main subject group in step S119. In step S114, if there is no focus detection success line within the middle defocus range, in step S120, the line A is renamed as line O, and the focus detection success line that captures the second closest subject from the camera. Is line A.
[0076]
Next, the process proceeds to step S121, and as in step S114, it is confirmed whether a focus detection success line exists in the middle defocus range from the line A to the infinity side with respect to the camera. If there are, all these lines are named line B (S122), and the process proceeds to step S123. Similar to step S116, there is a focus detection line in the small defocus range from line B that captures the subject farthest from the camera. Confirm whether to do. If there are, all these lines are named line C in step S124. In this case, line O, line A, line B, and line C are set as the main subject group.
[0077]
If the focus detection success line does not exist within the small defocus range in step S123, line O, line A, and line B are set as the main subject group. If there is no focus detection success line in the middle defocus range in step S121, line O and line A are set as the main subject group.
[0078]
As described above, the main subject group is defined based on the subject closest to the camera.
[0079]
When the main subject group is defined in this way, the process proceeds to step S103 in FIG. 7, and specific points are given to the lines O, A, B, and C. FIG. 9 shows the scoring rules at this time.
[0080]
In the present embodiment, for each piece of information obtained, a high score is given to a focus detection point where the main subject will be present, and a low score is given to a focus detection point that is not. Furthermore, although the range of the number of points to be allocated can be arbitrarily set, in the present embodiment, 1 to 5 points are allocated to each focus detection point.
[0081]
In the scoring rule of FIG. 9, first, classification is made according to which of lines O, A, B, and C is present in the line that captures the subject group by defocus amount detection. Further, the focus detection points that capture the lines O, A, B, and C existing in the group are classified according to whether they are adjacent to each other or separated from each other on the photographing screen. Points are given to the lines O, A, B, and C thus classified. However, according to the flowchart of FIG. 8, there are only one or zero lines O and A, respectively, but there may be a plurality of lines B and C depending on the grouping. Yes, #B is provided for the case where there are a plurality of lines B that greatly affect the configuration of the main subject.
[0082]
An example will be described with reference to FIG.
[0083]
The focus detection points 205 where the focus detection points were not possible are excluded from the target, and points are assigned to the remaining focus detection points. If the focus detection point 203 becomes line A, first, the focus detection point is given a score of 5. Line B is named focus detection points 200 and 204. At this time, the focus detection point 204 adjacent to the focus detection point 203 is given a score of 4, but the focus detection point 200 away from these is given a score of 5. The focus detection point 206 named line C is given a score of 4. Although other focus detections are possible, the focus detection points 201 and 202 that capture a subject existing at a long distance are given a score of 1. In this way, the number of points attached to the line can be made to correspond to all actual focus detection points as subject space information in step S104. By the way, in this case,
[0084]
[Formula 2]

[0085]
It becomes.
[0086]
After scoring the subject space information in this way, the process returns to the main routine of FIG. 6 via step S104 of FIG. 7, and proceeds to step S200.
[0087]
In step S200 of FIG. 6, the posture of the camera is detected by the posture sensor 27 provided in the main body. As a result, whether the photographer is holding the camera in the horizontal position or in the vertical position, and if it is in the vertical position, the camera grip 40 is held in the celestial direction or in the ground direction. It can detect how to hold. These three types of ways are shown in FIGS. 11A, 11B, and 11C.
[0088]
When the camera posture detection is completed, the process proceeds to step S201, and the focus detection point information is scored. The focus detection point information represents the relative arrangement state of the focus detection points on the photographing screen depending on how the camera is held, and the main subject appearance frequency as a general tendency corresponding thereto. In other words, considering the fact that there are generally many compositions that place the main subject closer to the center or above the shooting screen, the point operation is performed so that the focus detection point near or above the shooting screen can be easily selected. It is. On the other hand, this is also an operation for removing the adverse effect of applying this idea to the conventional sieving method, such that a specific focus detection point is extremely difficult to select.
[0089]
Specifically, the focus detection point information is scored as follows:
[0090]
[Formula 3]

[0091]
In accordance with the score map shown in FIG. 12, each of (A), (B), and (C) of the camera state diagram 11
[0092]
[Formula 4]

[0093]
In this embodiment, it is determined.
[0094]
Next, the process proceeds to step S300 to detect the photographer's line of sight. Since the gaze detection principle is as shown in the conventional example, it is omitted here.
[0095]
Approximate coordinates (Xn, Yn) are detected, although there are some errors, which point the photographer is observing on the shooting screen by eye gaze detection. When the approximate coordinates (Xn, Yn) are detected, the process proceeds to step S301, and the line-of-sight information is scored.
[0096]
What is gaze information scoring?
[0097]
[Formula 5]

[0098]
In other words, a numerical value is assigned to each focus detection point based on the line-of-sight coordinates. Specifically, a description will be given using a subroutine showing the operation of scoring the line-of-sight information in FIG.
[0099]
When the scoring of the line-of-sight information, which is a subroutine, starts in step S301, the process proceeds to step S311 to associate the line-of-sight coordinates with the imaging screen area. The shooting screen area is an area obtained by dividing the shooting screen into 19 areas as shown in FIG. a In the present embodiment, it is defined as ~ s. The object is to change the number of points given to the seven focus detection points depending on which area the detected line-of-sight coordinates (Xn, Yn) belong to. Therefore, in step S311, specifically, the transformation from the line-of-sight coordinates to the imaging screen area is performed.
[0100]
Next, in step S312, score allocation from the shooting screen area to each focus detection point is performed. In this embodiment, the scoring rules shown in FIG. 15 are applied. This is each area in FIG. a In contrast, when the detected line-of-sight coordinates belong to that region, the camera is high based on which of the seven focus detection points it is appropriate to perform the focus adjustment operation of the photographing lens. The score is assigned from the lowest score to the lowest score. For example, area a If line-of-sight coordinates (Xn, Yn) are detected in a The focus detection points targeted by Area a Is the closest focus detection point 204, and a score of 5 is given to this focus detection point, and a score of 1 is given to the other focus detection points.
[0101]
Further, when detected in the area o, the focus detection point 205 included in the area o is given the highest score of 5, and the focus detection point 202 adjacent to the focus detection point 205 has a score of 4 and the next closest focus detection point. 201 and 203 are given a score of 3, and focus detection points 200 and 204 that are outside the object of area o. , 206 Is given 1 point. This is based on the assumption that the detected line-of-sight coordinates contain errors, so even if a focus detection point exists in the area, only that point is not targeted, This is to give the possibility of being selected as a focus detection point for finally performing the focus adjustment operation of the photographing lens for all the focus detection points.
[0102]
When the scoring of the line-of-sight information is completed by the above operation, the process returns to the main routine of FIG. 6 and proceeds to the information fusion / comparison operation in step S400. Here, the subject space information, the focus detection point information, and the line-of-sight information digitized by the routine so far are fused, and comparison is made among the seven focus detection points.
[0103]
The total score of each focus detection point,
[0104]
[Formula 6]

[0105]
We will calculate with
[0106]
In this embodiment, d _i , P _i , E _i Is given in the range of 0 to 5 points. In other words, all information is handled equally. Therefore, α, β, and γ are prepared as weighting coefficients between the pieces of information. This is a coefficient that can be freely set depending on which information is important. For example, if gaze information is handled as auxiliary information and subject space information and focus detection point information are handled as main information, γ may be reduced and α and β may be increased, and conversely, if gaze information is emphasized, γ Should be increased.
[0107]
Thus, the total score of each focus detection point totaled through the weighting coefficient is compared. In the present embodiment, a high score is given to a focus detection point where the main subject is likely to be, a low score is given to a focus detection point that is not, and a high ratio is given to weighted coefficients for more important information. Therefore, it is only necessary to select the focus detection point having the highest total score as to which focus detection point the focus adjustment operation of the photographing lens is finally performed (step S500).
[0108]
Through the above process, one focus detection point for finally performing the focus adjustment operation of the photographing lens is selected. When one focus detection point is selected, the focus detection point is notified to the photographer in a superimpose display, and a known shooting operation is executed.
[0109]
According to the above embodiment, various information obtained from the sensor group (line sensor group 6f, image sensor 14, attitude sensor 27) provided in the camera is digitized with reference to the focus detection point, and finally Because it is a method of selecting a focus detection point for performing the focus adjustment operation of the photographic lens according to the number of values obtained in total, it is difficult to select a specific focus detection point among a plurality of focus detection points, This solves the problem that a slightly different focus result can be obtained by a slight change in the way the subject or the camera is held.
[0110]
Specifically, subject space information based on the amount of defocus detected by a plurality of focus detection points and distance to the subject, focus detection point information indicating the frequency of appearance of the main subject depending on how the camera is held, and the photographer At least two pieces of line-of-sight information that represent the gaze coordinates on the photographing screen are used. In addition, when adding information, the ratio of addition is changed depending on which information category has priority. In addition, a subject group that is located at a fixed distance from the subject closest to the camera, captured at the focus detection point, is defined as a subject group. In the case where it is considered that there is a subject that is spatially separated in the subject group, a score that is equally likely to be a main subject is assigned. In addition, when the shooting screen is divided into a plurality of areas and the line-of-sight coordinates are calculated in a certain area, the focus detection point is determined based on which focus detection point is appropriate for the focus adjustment operation of the shooting lens. A scoring map with points is prepared.
[0111]
In addition, the conventional automatic selection algorithm did not capture the photographer's intention as information, so it was possible to focus on an unexpected subject, or on the other hand, to select the focus detection point based on the photographer's line of sight In the system, since the gaze coordinates on the photographing screen cannot be detected accurately for various reasons, the coordinates are not necessarily coincident with the coordinates intended by the photographer. But book Implementation According to this form, without focusing on specific information, each information is digitized to compensate for the lack of each other's information and select the focus detection point that is most likely to have the main subject overall. Therefore, it has become possible to realize a capture rate of the main subject that could not be achieved by the conventional algorithm.
[0112]
(Modification)
As the information category, in the above embodiment, the subject space information, the focus detection point information, and the line-of-sight information are targeted, but finally the focus detection point for performing the focus adjustment operation of the photographing lens is selected. As information for doing this, only two of them may be used.
[0113]
Similarly, the category of information to be targeted is not limited to these three, and may be a category target as long as it is significant information for selecting a focus detection point.
[0114]
In addition, although seven focus detection points are used, the number of points is not limited to this.
[0115]
Moreover, although the integer value of 0-5 was used for the set score range for information scoring, any real value may be set for this range. In addition, the higher the score is given to the focus detection point at which the subject is supposed to exist, the lower the score is given to the focus detection point, and the focus detection point to which the lowest score is finally given is selected. You may do it.
[0116]
The scoring map for each information used in the present embodiment can be arbitrarily changed according to the actual situation.
[0117]
Further, the number of area divisions of the photographing screen in the line-of-sight information is set to 19 and set as shown in FIG.
[0118]
Further, the order of scoring in this embodiment is the order of subject space information → focus detection point information → line-of-sight information, but this order can be arbitrarily set.
[0119]
【The invention's effect】
As described above, according to the present invention, it is difficult to select a specific focus detection point from among a plurality of focus detection points, or the focus is greatly shifted due to a slight change in the manner of holding the subject or the camera. Autofocus camera that can be eliminated Can offer Is.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a main part of a single-lens reflex camera according to an embodiment of the present invention.
2 is an external view of a main part of the single-lens reflex camera of FIG. 1. FIG.
FIG. 3 is a view of the viewfinder in FIG. 1;
4 is a block diagram showing an electrical configuration of the single-lens reflex camera of FIG. 1. FIG.
FIG. 5 is a diagram for explaining a display state in the viewfinder field of FIG. 3;
FIG. 6 is a flowchart showing an operation in one embodiment of the present invention.
FIG. 7 is a flowchart showing a subroutine in FIG. 6;
FIG. 8 is a flowchart showing the subroutine in FIG. 6;
FIG. 9 is a scoring map according to the embodiment of the present invention.
FIG. 10 is a diagram showing an example of scoring in an embodiment of the present invention.
FIG. 11 is a diagram for explaining how to hold a general camera.
FIG. 12 is a scoring map according to one embodiment of the present invention.
FIG. 13 is a flowchart showing a subroutine in FIG. 6;
FIG. 14 is a diagram showing shooting screen division according to the embodiment of the present invention.
FIG. 15 is a scoring map according to one embodiment of the present invention.
FIG. 16 is a view of a conventional fanda field.
FIG. 17 is a flowchart showing a conventional automatic selection algorithm.
FIG. 18 is a schematic diagram of a main part of a general visual line detection device.
FIG. 19 is a schematic view of a main part of an eyeball image.
FIG. 20 is a diagram illustrating an example of a shooting scene.
FIG. 21 is a diagram showing another example of an assessment scene.
[Explanation of symbols]
1 Photo lens
6 Focus detection device
6f Line sensor group
13 Infrared light emitting diode (IRED)
14 Image sensor (CCD-EYE)
24 LCD in the viewfinder
27 Attitude sensor
41 Release button
46 Focus detection point selection button
100 CPU
101 Eye-gaze detection circuit
103 Focus detection circuit
110 Focus adjustment circuit
200-206 Focus detection point

Claims (3)

In an autofocus camera having a focusing unit that selects one focus detection point from among a plurality of focus detection points on a shooting screen and performs focus adjustment operation of a shooting lens based on focus detection information obtained at the focus detection point ,
First detection means for detecting a defocus amount for each focus detection point ;
A second detection means for detecting the posture;
One focus detection point closest to the defocus amount corresponding to the plurality of focus detection points detected by the first detection means and the defocus amount on the infinity side that is discrete to the one focus detection point The number of focus detection points shown is not discrete at the one focus detection point, and is higher than the number of focus detection points showing the defocus amount on the infinity side, and is detected by the second detection means Scoring means for assigning a score to each of the plurality of focus detection points according to a scoring map determined in advance based on the determined posture ;
Said focusing means, by the scoring means, the amount of numerical values the sum granted a score of said plurality of focus detecting points for each of the focus detection point, one focus of the plurality of focus detection points An autofocus camera characterized by selecting a detection point and performing a focus adjustment operation of the taking lens. The scoring means, autofocus camera according to claim 1, characterized in that imparts a score based on the detection result of the third detecting means for detecting the gazing point on the imaging screen of the photographer. It said focusing means, by the scoring means, when the total previous SL plurality of focus detection points score for each respective focus detection point, and performs weighting for each of the plurality of detecting means The autofocus camera according to claim 1 or 2 .

Images