JP2004117195A - Digital camera with speed measuring function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel digital camera consisting of a solid imaging element, having the function of measuring the speed of a moving subject. <P>SOLUTION: The digital camera uses a photographing optical system 14 for forming an optical subject image on the receiving face of a solid imaging element 32 at a predetermined photograph magnifying power for a preset charge accumulating time and photoelectrically converting it into one-frame pixel signals to generate a photographic image in accordance with the one-frame pixel signals. The digital camera has the speed measuring function for measuring the speed of the moving subject in accordance with the photograph magnifying power and the charge accumulating time when the photographic image is photographed as a measured image including the moving subject. <P>COPYRIGHT: (C)2004,JPO

Description

【００４１】
背景画像（図２）から位置補正背景画像（図４）を得るために、該背景画像をＸ−Ｙ座標原点の回りで回転させる回転角度θ及びＸ−Ｙ座標系に対して背景画像を平行移動させるための平行移動量（Δｘ，Δｙ）は以下のように表せる。
θ＝ｓｉｎ^−１（ｕ_ｅｙ_ｅ　−　ｖ_ｅｘ_ｅ）
Δｘ＝ｘ_１　−　ｕ_１
Δｙ＝ｙ_１　−　ｖ_１
【００４２】
即ち、位置補正背景画像（図４）の任意の画素信号の座標Ｐ_ｉ（ｘ_ｉ，　ｙ_ｉ）とされたとき、その座標Ｐ_ｉ（ｘ_ｉ，　ｙ_ｉ）に対応した元の背景画像（図２）の上の画素信号の座標Ｐ_ｏｒｇ（ｘ_ｏｒｇ，　ｙ_ｏｒｇ）は以下の式で表せる。
ｘ_ｏｒｇ＝（ｘ_ｉ　−　ｕ_ｉ）ｃｏｓθ　−　（ｙ_ｉ　−　ｖ_ｉ）ｓｉｎθ　＋　Δｘ
ｙ_ｏｒｇ＝（ｘ_ｉ　−　ｕ_ｉ）ｓｉｎθ　＋　（ｙ_ｉ　−　ｖ_ｉ）ｃｏｓθ　＋　Δｙ
【００４３】
位置補正背景画像（図４）上で座標Ｐ_ｉ（ｘ_ｉ，　ｙ_ｉ）で表された画素信号は測定画像（図３）上の画素信号に対応するものである。従って、座標Ｐ_ｉ（ｘ_ｉ，　ｙ_ｉ）で表される画素信号と背景画像（図２）上で座標Ｐ_ｏｒｇ（ｘ_ｏｒｇ，　ｙ_ｏｒｇ）で表せる画素信号とは互いに対応するので、その輝度値の差分がほぼ等しいとき、即ち所定の微小範囲内に含まれるとき、測定画像（図３）上で座標Ｐ_ｉ（ｘ_ｉ，　ｙ_ｉ）で表される画素信号は像ブレ領域ＢＲに含まれないものとして該測定画像から除去される。一方、該双方輝度値の差分が大巾に異なるとき、即ち上述の所定の微小範囲外となるとき、測定画像（図３）側上で座標Ｐ_ｉ（ｘ_ｉ，　ｙ_ｉ）で表される画素信号は像ブレ領域ＢＲに含まるものとして該測定画像に残される。
【００４４】
このような処理を繰り返すことにより、測定画像（２）から背景画像が除去されて像ブレ領域ＢＲだけが図５に示すように抽出される。次いで、図６に示すように、像ブレ領域ＢＲの幅Ｗ_Ｃ及びその高さＨ_Ｃが画像処理により求められる。その後、ボール速度Ｓ_Ｂが以下の式により演算される。
Ｓ_Ｂ＝（Ｗ_Ｃ　−　Ｈ_Ｃ）／ＭＴ_Ｃ
ここで、“Ｍ”は測定画像の撮影倍率であり、“Ｔ_Ｃ”は測定画像（図３）の電荷蓄積時間である。
【００４５】
図７を参照すると、メインスイッチ（ＳＷ_Ｍ）１２がオンされた直後にシステム制御回路１０で一度だけ実行される初期化ルーチンのフローチャートが示される。
【００４６】
ステップ７０１では、記録モード及び再生モードのいずれかが選択されているか否かが判断される。即ち、メインスイッチ１２のオン時に、例えば記録／再生スイッチ（Ｒ／Ｐ　ＳＷ）２６が記録側にあれば、記録モードが選択され、このときステップ７０２に進み、そこで撮影処理ルーチンの実行開始が指令される。一方、メインスイッチ１２のオン時に、記録／再生スイッチ（Ｒ／Ｐ　ＳＷ）２６が再生側にあれば、ステップ７０３に進み、そこで再生処理ルーチンの実行開始が指令される。なお、撮影処理ルーチンは本デジタルカメラを用いて被写体を撮影する際に実行されるものであり、再生処理ルーチンは撮影された画像をＬＣＤパネル５０でモニタする際に実行されるものであり、撮影処理ルーチンについては図１０を参照して、再生処理ルーチンについては図１１及び図１２を参照して後で詳しく説明する。
【００４７】
ステップ７０４では、フラグＢＦＫ及びＳＭＦが“０”に初期化される。フラグＢＫＦは記録モード時に被写体を速度計測の際に使用される背景画像（図２）として撮影する背景画像撮影モードが選択されているか否かを指示するためのフラグであり、ＢＫＦ＝１のとき、背景画像撮影モードが選択されていることが指示され、ＢＫＦ＝０のとき、背景画像撮影モードの選択が解除されていることが指示される。また、フラグＳＭＦは再生モード時に速度計測モードが選択されているか否かを指示するためのフラグであり、ＳＭＦ＝１のとき、速度計測モードが選択されていることが指示され、ＳＭＦ＝０のとき、速度計測モードの選択が解除されていることが指示される。ステップ７０５では、その他の初期化処理が実行されるが、これら初期化化処理自体は本発明には特に直接関係しないものである。
【００４８】
図８及び図９を参照すると、システム制御回路１０で実行されるスイッチ操作監視ルーチンのフローチャートが示され、このスイッチ操作監視処理ルーチンの実行開始は図７の初期化ルーチンの実行完了後となる。
【００４９】
ステップ８０１では、記録／再生スイッチ（Ｒ／Ｐ　ＳＷ）２６が操作されたか否かが監視され、記録／再生スイッチ２６の操作が確認されると、ステップ８０２に進み、そこで記録モードが選択されたか否かが判断される。記録／再生スイッチ２６の操作により記録モードが選択されたことが確認されると、ステップ８０３に進み、そこで再生処理ルーチンの実行停止が指令され、次いでステップ８０４に進み、そこで撮影処理ルーチンの実行開始が指令される。一方、ステップ８０２で再生モードが選択されたことが確認されると、ステップ８０５に進み、そこで撮影処理ルーチンの実行停止が指令され、次いでステップ８０６に進み、そこで再生処理ルーチンの実行開始が指令される。
【００５０】
ステップ８０１で記録／再生スイッチ２６の操作が確認されないとき、或いは撮影処理ルーチンの実行開始指令後（ステップ８０４）若しくは再生処理ルーチンの実行開始指令後（ステップ８０６）の実行後、ステップ８０７に進み、そこでメニュー表示スイッチ（ＳＷ_ＭＤ）５８が操作されたか否かが監視される。メニュー表示スイッチ５８の操作が確認されると（即ち、ＬＣＤパネル５０の表示がメニュー表示画面に切り替わると）、ステップ８０８に進み、そこで実行中の処理が中断される。即ち、例えば、撮影処理ルーチンが実行されていれば、その撮影処理ルーチンの実行が中断され、再生処理ルーチンが実行されていれば、その再生処理ルーチンの実行が中断される。
【００５１】
ステップ８０９では、メニュー選択スイッチ（ＳＷ_Ｓ）６０の操作に従ってメニュー表示処理が実行される。即ち、メニュー表示処理では、メニュー選択スイッチ（十字スイッチ）６０を操作することにより、反転カーソルがシフトさせられる。ステップ８１０では、メニュー確定スイッチ（ＳＷ_Ｋ）６２が操作されたか否かが監視される。要するに、メニュー確定スイッチ６２の操作が確認されるまで、メニュー表示処理がメニュー選択スイッチ６０の操作に従って続けられ、所望のメニュー選択が行われる。
【００５２】
ステップ８１０でメニュー確定スイッチ６２の操作が確認されると、即ち選択メニューが確定すると、ステップ８１１に進み、選択メニューが速度計測メニューであるか否かが判断される。もし速度計測メニューが選択されたならば、ステップ８１２に進み、フラグＳＭＦに“１”が与えられ、これにより速度計測モードが選ばれたことが指示される。選択メニューが背景画像撮影メニューではないとき、ステップ８１１からステップ８１３に進み、そこで選択メニューが速度計測解除メニューであるか否かが判断される。もし速度計測解除メニューが選択されたならば、ステップ８１４に進み、そこでフラグＳＭＦに“０”が与えられ、これにより速度計測モードの選択が解除されたことが指示される。
【００５３】
選択メニューが速度計測メニューでも速度計測解除メニューでもないとき、ステップ８１３からステップ８１５に進み、そこで選択メニューが背景画像撮影メニューであるか否かが判断される。もし背景画像撮影メニューが選択されたならば、ステップ８１６に進み、フラグＢＫＦに“１”が与えられ、これにより背景画像撮影モードが選ばれたことが指示される。選択メニューが背景画像撮影メニューではないとき、ステップ８１５からステップ８１７に進み、そこで選択メニューが背景画像撮影解除メニューであるか否かが判断される。もし解除メニューが選択されたならば、ステップ８１８に進み、そこでフラグＢＫＦに“０”が与えられ、これにより背景画像撮影モードの選択が解除されたことが指示される。
【００５４】
選択メニューが背景画像撮影メニューでも背景画像撮影解除メニューでもないとき、ステップ８１７からステップ８１９に進み、そこでメニュー確定スイッチ６２の操作により確定されたその他のメニューに従う処理が実行される。なお、そのような選択メニュー自体は本発明とは直接関係するものではないので説明を省略する。
【００５５】
その後、ステップ８２０に進み、そこで中断中の処理（８０８）が再開される。次いで、ステップ８２１でメインスイッチ１２がオフされたか否かが判断され、もしメインスイッチ１２がオン状態であれば、ステップ８０１に戻り、記録／再生スイッチ２６及びメニュー表示スイッチ５８の操作が監視される。一方、ステップ８２１でもしメインスイッチ１２がオフであれば、ステップ８２２に進み、そこでスリープモードに移行して本ルーチンは終了する。
【００５６】
図１０を参照すると、撮影処理ルーチンのフローチャートが示され、この撮影処理ルーチンの実行開始指令は既に述べたように初期化ルーチン（図７）のステップ７０２或いはスイッチ操作監視処理ルーチン（図８及び図９）のステップ８０４で行われる。
【００５７】
ステップ１００１では、ＬＣＤパネル表示処理ルーチンが実行される。このようなＬＣＤパネル表示処理ルーチン自体は従来のデジタルカメラでよく知られているものであり、その実行によりＬＣＤパネル４８には上述したような態様で被写体像が動画として表示される。即ち、ＣＣＤ撮像素子３２からは一フレーム分の間引きカラー画素信号が所定の時間間隔で順次読み出され、これら間引きカラー画素信号に基づいて被写体像がＬＣＤパネル５０に動画として表示される。なお、ＬＣＤパネル表示処理ルーチンの実行中、ＣＣＤ撮像素子３２から一フレーム分の間引きカラー画素信号が読み出される度毎に、合焦レンズ機構２４が上述したようなコントラスト法に従って駆動させられ、これによりＬＣＤパネル５０での動画表示は常にピントが合った状態で行われる。
【００５８】
ステップ１００２では、ズーム処理ルーチンが実行される。このようなズーム処理ルーチン自体も従来のデジタルカメラでよく知られているものである。即ち、ズーム処理ルーチンでは、テレ側スイッチ（ＳＷ_Ｔ）１８及びワイド側スイッチ（ＳＷ_ｗ）２０のいずれかの操作が監視され、この双方のスイッチの一方が操作されると、ズーム駆動機構１６が駆動されて撮影光学系１４の焦点距離はｆ_１、ｆ_２、ｆ_３、ｆ_４及びｆ_５のうちの１つに設定される。
【００５９】
ステップ１００３では、レリーズスイッチ釦の半押しによって、測光スイッチ（ＳＷ_Ｐ）２８がオンされたか否かが監視される。もし測光スイッチ２８がオフであれば、ステップ１００２に戻る。要するに、撮影光学系１４で捉えられた被写体像をＬＣＤパネル５０に動画として表示しつつ、測光スイッチ２８のオン操作がステップ１００３で監視される。
【００６０】
ステップ１００３で測光スイッチ２８のオン操作が確認されると、ステップ１００４に進み、そこで測光処理が実行される。測光処理では、ＣＣＤ撮像素子３２から読み出された一フレーム分の間引きカラー画素信号から得られた一フレーム分の輝度信号の平均輝度値（測光値）に基づいて最適露出値が求められる。次いで、ステップ１００５では、合焦レンズ機構２４が上述したコントラスト法に従って駆動させられ、これにより撮影動作直前の合焦処理が実行される。
【００６１】
ステップ１００６では、ズームエンコーダ２２から焦点距離データが取り込まれ、現時点で撮影光学系１４で設定されている焦点距離（ｆ_１、ｆ_２、ｆ_３、ｆ_４、ｆ_５）が焦点距離データによって認識される。次いで、ステップ１００７では、焦点距離データに基づいて被写体距離が演算され、続いてステップ１００８で撮影倍率Ｍが演算される。
【００６２】
ステップ１００９では、ステップ１００４で得られた最適露出値に基づいて電荷蓄積時間Ｔ_Ｃが演算される。次いで、ステップ１０１０では、レリーズスイッチ釦の全押しにより、レリーズスイッチ（ＳＷ_Ｒ）３０がオンされた否かが監視される。もしレリーズスイッチ３０がオフであれば、ステップ１００１に戻る。もし測光スイッチ２８のオン状態が維持されていれば、ステップ１００４ないし１００９の撮影直前処理が繰り返される。
【００６３】
ステップ１０１０でレリーズスイッチ３０のオンが確認されると、ステップ１０１１に進み、そこでＣＣＤ撮像素子３２から不要電荷が掃き出される。次いで、ステップ１０１２では、電荷蓄積時間Ｔ_Ｃの経過が監視される。電荷蓄積時間Ｔ_Ｃの経過が確認されると、ステップ１０１３に進み、そこでＣＣＤ撮像素子３２から一フレーム分のカラー画素信号が間引きかれることなくすべて読み出され、この一フレーム分のカラー画素信号は相関二重サンプリング回路３８、増幅器４０及びＡ／Ｄ変換器４２を経て一フレーム分のデジタルカラー画素信号としてシステム制御回路１０に取り込まれる。
【００６４】
そして、一フレーム分のデジタルカラー画素信号はホワイトバランス処理、ガンマ補正処理等の画像処理が施され、静止画データが生成される（ステップ１０１４）。次いで、ステップ１０１５では、速度計測モードが選択されているか否かが判断される。速度計測モードが選択されているとき（ＳＭＦ＝１）、ステップ１０１６に進み、そこで静止画データがインタフェース（Ｉ／Ｆ）回路５６及びＣＦカードドライバ５４を介してＣＦカードメモリ５３の所定のメモリ領域に所定のフォーマットに従って書き込まれ、このとき撮影倍率データ（Ｍ）、電荷蓄積時間データ（Ｔ_Ｃ）及びフラグデータ（ＢＫＦ）も該メモリ領域のヘッダに格納される。即ち、速度計測モードの選択時には、ＣＦカードメモリ５３には静止画像データと共に撮影倍率データ（Ｍ）、電荷蓄積時間データ（Ｔ_Ｃ）及びフラグデータ（ＢＫＦ）が格納され、その静止画像データがフラグデータ（ＢＫＦ）により背景画像データ（ＢＦＦ＝１）及び測定画像データ（ＢＦＦ＝０）のいずれであるかが判別され得るようにされる。
【００６５】
ステップ１０１７では、ＦＣカードメモリ５３のヘッダ領域を検索し、フラグデータＢＦＦ＝１の背景画像とフラグデータＢＫＦ＝０の測定画像がそれぞれ１枚以上あるか否かが判断される。背景画像と測定画像の双方がある場合には、図１１及び図１２に示す再生処理ルーチンのステップ１１０２にジャップし、直ちに再生モード下での速度計測動作に移行する。なお、速度計測動作については図１１及び図１２を参照して後で詳しく説明する。速度計測を目的として撮影行う場合、速度計測に必要な一対の背景画像と計測画像は比較的近い時間間隔で撮影されるケースが多い。そして、計測画像と背景画像の一方を撮影した後、他方を撮影するケースも頻度が高い。また、背景画像は同じ背景で同じ背景で撮影された各測定画像に対しては共用できるため、計測したい画像を先に複数枚撮影した後、最後に背景画像を１枚撮影するケースも多い（シャッターチャンスの関係から、撮影の優先度が測定画像の方が高い）。従って、上記構成にしておけば、最後に背景画像が撮影されて、速度計測が可能な条件が満たされると、直ちに再生モード下における速度計測処理に移行するので、手動操作によって記録モードから再生モードに変更する煩わしさから解放される。
【００６６】
一方、ステップ１０１５で速度計測モードが選択されていない場合（フラグＳＭＦ＝０）、即ち通常の撮影が行われた場合には、ステップ１０１５からステップ１０１９に進み、そこで静止画像データがインタフェース（Ｉ／Ｆ）回路５６及びＣＦカードドライバ５４内を介してＣＦカードメモリ５３の所定のメモリ領域に所定のフォーマットに従って書き込まれ、このときＣＦカードメモリ５３のヘッダ領域には、撮影倍率データＭ及びフラグデータ（ＢＫＦ）は記録されない。
【００６７】
図１１及び図１２を参照すると、再生処理ルーチンのフローチャートが示され、この再生処理ルーチンの実行開始指令は既に述べたように初期化ルーチン（図７）のステップ７０３或いはスイッチ操作監視処理ルーチン（図８及び図９）のステップ８０６で行われる。
【００６８】
ステップ１１０１では、フラグＳＭＦが“１”であるか“０”であるかが判断される。ＳＭＦ＝０であるとき、即ち速度計測モードの選択が解除されているとき、ステップ１１０２に進み、そこで通常再生処理が実行される。この通常再生処理はＣＦカードメモリに格納された静止画像データに基づいて撮影画像を所定の手続きに従ってＬＣＤパネル５０でモニタするための処理であり、このような再生処理自体は従来のデジタルカメラで行われているものである。なお、ＬＣＤパネル５０での撮影画像の再生画面には速度計測モードの選択メニューが表示され、速度計測モードをメニュー選択スイッチ（ＳＷ_Ｓ）６０で選択した後にメニュー確定スイッチ（ＳＷ_Ｋ）６２を操作すると、フラグＳＭＦは“０”から“１”に書き換えられる。
【００６９】
ステップ１１０１でＳＭＦ＝１のとき、即ち速度計測モニタが選択されているとき、ステップ１１０３に進み、そこで背景画像（図２）の検索が行われる。即ち、ＣＦカードメモリ内に格納された静止画像データの中でフラグデータ（ＢＫＦ）に“１”が与えられている静止画像データが検索される。次いで、ステップ１１０４で背景画像の検索結果が判断される。即ち、背景画像がＣＦカードメモリ内に含まれているときには、ステップ１１０５に進み、そこで背景画像（図２）がＬＣＤパネル５０に表示される。即ち、ＢＫＦ＝１とされた静止画像データ即ち背景画像データがＣＦカードメモリから間引かれて読み出され、この間引き背景画像データから表示用ビデオ信号が作成され、このビデオ信号に基づいて背景画像がＬＣＤパネル５０に表示される。なお、背景画像が複数枚あるときには、その枚数をＬＣＤパネル５０に表示することが好ましい。
【００７０】
ステップ１１０６では、メニュー選択スイッチ６０の操作に従って背景画像の表示切替処理が行われ、次いでステップ１１０７でメニュー確定スイッチ６２が操作されたか否かが判断される。メニュー確定スイッチ６２の操作が確認されないときには、ステップ１１０６に戻る。要するに、メニュー確定スイッチ６２が操作されるまでは、メニュー選択スイッチ６０の操作に従って背景画像の表示が切り替わり、これにより背景画像の選択が行われる。ステップ１１０７でメニュー確定スイッチ６２の操作が確認されると、即ち背景画像の選択が確定されると、ステップ１１０８に進み、そこで確定背景画像に対応した一フレーム分の静止画像データが間引かれることなくＣＦカードメモリからすべて読み出されてＤＲＡＭ５２に一旦格納される。
【００７１】
ステップ１１０９では、測定画像（図３）の検索が行われる。即ち、ＣＦカードメモリ内に格納された静止画像データの中でフラグデータ（ＢＫＦ）に“０”が与えられている静止画像データが検索される。次いで、ステップ１１１０で測定画像の検索結果が判断される。即ち、測定画像がＣＦカードメモリ内に含まれているときには、ステップ１１１０に進み、そこで測定画像（図３）がＬＣＤパネル５０に表示される。即ち、ＢＫＦ＝０とされた静止画像データ即ち測定画像データがＣＦカードメモリから間引かれて読み出され、この間引き測定画像データから表示用ビデオ信号が作成され、このビデオ信号に基づいて背景画像がＬＣＤパネル５０に表示される。なお、測定画像が複数枚あるときには、その枚数をＬＣＤパネル５０に表示することが好ましい。
【００７２】
ステップ１１１２では、メニュー選択スイッチ６０の操作に従って測定画像の表示切替処理が行われ、次いでステップ１１１３でメニュー確定スイッチ６２が操作されたか否かが判断される。メニュー確定スイッチ６２の操作が確認されないときには、ステップ１１１２に戻る。要するに、メニュー確定スイッチ６２が操作されるまでは、メニュー選択スイッチ６０の操作に従って測定画像の表示が切り替わり、これにより測定画像の選択が行われる。ステップ１１１３でメニュー確定スイッチ６２の操作が確認されると、即ち測定画像の選択が確定されると、ステップ１１１４に進み、そこで確定測定画像に対応した一フレーム分の静止画像データが間引かれることなくＣＦカードメモリからすべて読み出されてＤＲＡＭ５２に一旦格納される。
【００７３】
ステップ１１１５では、確定背景画像（ステップ１１０８）の撮影倍率（Ｍ）と確定測定画像（ステップ１１１４）の撮影倍率（Ｍ）とが一致しているが否かが判断される。双方の画像の撮影倍率が不一致のときには、ステップ１１１６に進み、そこで撮影倍率の不一致のために速度計測が不能である旨の警告表示がＬＣＤパネル５０で行われ、次いでステップ１１１２に戻る。即ち、その他の測定画像の選択が促される。
【００７４】
ステップ１１１５で確定背景画像と確定測定画像との撮影倍率（Ｍ）が一致していることが確認されたとき、ステップ１１１７に進み、そこで背景画像（図２）からターゲットＴＧの小円反射領域Ｒ_１及びＲ_２のそれぞれの中心座標Ｐ_１（ｘ_１，　ｙ_１）及びＰ_２（ｘ_２，　ｙ_２）がラベリング処理等の画像処理によって求められ、また測定画像（図３）からターゲットＴＧの２つの小円反射領域Ｒ_１及びＲ_２のそれぞれの中心座標Ｑ_１（ｕ_１，　ｖ_１）及びＱ_２（ｕ_２，　ｖ_２）がラベリング処理等の画像処理によって求められ、これら中心座標から背景画像と測定画像のそれぞれの方向ベクトル（ｘ_ｅ，　ｙ_ｅ）及び（ｕ_ｅ，　ｖ_ｅ）が以下の式に基づいて演算される。
【数２】

【００７５】
ステップ１１１８では、測定画像（図３）に対する背景画像（図２）の回転角度θが以下の演算により求められる。
θ←　ｓｉｎ^−１（ｕ_ｅｙ_ｅ　−　ｖ_ｅｘ_ｅ）
【００７６】
ステップ１１１９では、測定画像（図３）に対する背景画像（図２）の平行移動量（Δｘ，Δｙ）が以下の演算により求められる。
Δｘ　←　ｘ_１　−　ｕ_１
Δｙ　←　ｙ_１　−　ｖ_１
【００７７】
ステップ１１２０では、上述の回転角度θ及び平行移動量（Δｘ，Δｙ）に基づいて位置補正背景画像（図４）が生成され、次いでステップ１１２１で測定画像（図２）を位置補正背景画像（図４）で差分処理することにより移動被写体の像ブレ領域ＢＲが抽出される。続いて、ステップ１１２２で像ブレ領域ＢＲの幅Ｗ_Ｃ及びその高さＨ_Ｃが画像処理により求められ、ステップ１１２３で移動被写体の速度Ｓ_Ｂが以下の演算により求められる。
Ｓ_Ｂ＝（Ｗ_Ｃ　−　Ｈ_Ｃ）／ＭＴ_Ｃ
勿論、ここで、“Ｍ”は測定画像（或いは背景画像）の撮影倍率であり、“Ｔ_Ｃ”は測定画像の電荷蓄積時間である。
【００７８】
ステップ１１２４では、上述のように演算された移動被写体の速度Ｓ_Ｂが図１３に例示的に示すようにＬＣＤパネル５０に表示された測定画像上にスパーインポーズされる。即ち、同図の例では、移動被写体即ちボールの速度として、９５ｋｍが測定画像上にスパーインポーズされる。かくして、本デジタルカメラのユーザはＬＣＤパネル５０に表示された測定画像中の移動被写体の速度を認識することができる。
【００７９】
ステップ１１２５では、メニュー選択スイッチ６０の操作に従って測定画像のメニュー選択処理が実行され、次いでステップ１１２５でメニュー確定スイッチ６２が操作されたか否かが判断される。メニュー確定スイッチ６２の操作が確認されないときには、ステップ１１１２に戻る。要するに、メニュー確定スイッチ６２が操作されるまでは、メニュー選択スイッチ６０の操作に従って測定画像上のメニュー選択処理が実行される。詳述すると、図１３に示すように、測定画面にはメニューとして“変更１”、“変更２”及び“終了”が表示され、図１３に示す例では、“変更１”が反転カーソルによって反転表示される。反転カーソルはメニュー選択スイッチ６０の操作により３つのメニュー、即ち“変更１”、“変更２”及び“終了”の間でシフトさせられ、反転表示のメニューが選択対象となる。
【００８０】
なお、ここでは、“変更１”は測定画像の変更を意味し、“変更２”は背景画像の変更を意味し、“終了”は速度計測モード選択の解除を意味する。
【００８１】
ステップ１１２６でメニュー確定スイッチ６２が操作されると、ステップ１１２７に進み、そこで選択メニューが“変更１”であるか否かが判断される。即ち、測定画像の変更が選択されたか否かが判断される。測定画像の変更が選択されたときは、ステップ１１１２に戻り、測定画像の表示切替処理が行われ、新たな測定画像が選択されると（ステップ１１１３）、その新たな測定画像に写された移動被写体の速度演算が上述した態様で行われる。
【００８２】
選択メニューが“変更１”即ち測定画像の変更でないとき、ステップ１１２７からステップ１１２８に進み、そこで選択メニューが“変更２”であるか否かが判断される。即ち、背景画像の変更が選択されたか否かが判断される。背景画像の変更が選択されたときは、ステップ１１０６に戻り、背景画像の表示切替処理が行われ、新たな背景画像が選択されると（ステップ１１０７）、その新たな背景画像に対する測定画像が適宜選択され（ステップ１１１２及び１１１３）、その後測定画像に写された移動被写体の速度演算が上述した態様で行われる。
【００８３】
選択メニューが“変更１”でも　“変更２”でもないとき、即ち“終了”が選択されたとき、ステップ１１２９に進み、そこでフラグＳＭＦが“１”から“０”に書き替えられた後にステップ１１０１に戻り、通常再生処理（ステップ１１０２）が実行されることになる。
【００８４】
上述の実施形態では、背景画像及び測定画像は共にデジタルカメラを手で持った状態で撮影することが前提とされているが、デジタルカメラを三脚上の固定して背景画像及び測定画像を撮影してもよく、この場合には背景画像を測定画像に一致させるための位置補正背景画像の生成処理については省くことができる。即ち、背景画像と測定画像とから直ちに移動被写体の像ブレ領域を抽出することができる。
【００８５】
また、上述の実施形態では、背景画像及び測定画像をそれぞれＣＦカードメモリに格納した後の画像再生モード時に移動被写体の速度演算が行われているが、速度演算処理をリアルタイム処理を行うことも可能である。即ち、例えば、或る時点で撮影された画像を背景画像として指定し、その後の撮影で得られる画像を測定画像とし、個々の測定画像が撮影される度毎に移動被写体の速度計測を行うようにしてもよい。
【００８６】
【発明の効果】
以上の記載から明らかなように、本発明によるデジタルカメラには撮影機能に加えて移動被写体の速度計測機能が与えられるので、その商品価値が高められるだけでなくデジタルカメラに対する新たな需要を喚起することができる。
【図面の簡単な説明】
【図１】本発明によるデジタルカメラの一実施形態を示す概略ブロック図である。
【図２】本発明による速度計測に用いられる背景画像を例示的に示す模式図である。
【図３】本発明による速度計測に用いられる測定画像を例示的に示す模式図である。
【図４】図２の背景画像を図３の測定画像に空間的に一致させるように位置補正された位置補正背景画像を示す模式図である。
【図５】図３の測定画像と図４の位置補正背景画像とから抽出された移動被写体の像ブレ領域を示す模式図である。
【図６】図５に示した移動被写体の像ブレ領域を拡大して示す拡大図であって、該移動被写体の速度計測に必要なディメンジョンを示す図である。
【図７】図１に示すシステム制御回路で実行される初期化ルーチンのフローチャートである。
【図８】図１に示すシステム制御回路で実行されるスイッチ操作監視処理ルーチンのフローチャートの一部である。
【図９】図８に示したスイッチ操作監視処理ルーチンのフローチャートの残りの部分である。
【図１０】図１に示すシステム制御回路で実行される撮影処理ルーチンのフローチャートである。
【図１１】図１に示すシステム制御回路で実行される再生処理ルーチンのフローチャートの一部である。
【図１２】図８に示した再生処理ルーチンのフローチャートの残りの部分である。
【図１３】速度計測モード時にＬＣＤパネルに表示される測定画像を例示的に示す模式図である。
【符号の説明】
１０　システム制御回路
１２　メインスイッチ（ＳＷ_Ｍ）
１４　撮影光学系
１６　ズーム駆動機構
１８　テレ側スイッチ（ＳＷ_Ｔ）
２０　ワイド側スイッチ（ＳＷ_Ｗ）
２２　ズームエンコーダ
２４　合焦レンズ駆動機構
２６　記録／再生スイッチ（Ｒ／Ｐ　ＳＷ）
２８　測光スイッチ（ＳＷ_Ｐ）
３０　レリーズスイッチ（ＳＷ_Ｒ）
３２　ＣＣＤ撮像素子
３４　光学的ローパスフィルタ（ＬＰＦ）
３６　ＣＣＤ駆動回路
３８　相関二重サンプリング回路（ＣＤＳ）
４０　増幅器（ＡＭＰ）
４２　アナログ／デジタル（Ａ／Ｄ）変換器
４４　ビデオラム（ＶＲＡＭ）
４６　デジタル／アナログ（Ｄ／Ａ）変換器
４８　ビデオエンコーダ
５０　液晶表示（ＬＣＤ）パネル
５２　ダイナミックラム（ＤＲＡＭ）
５４　ＣＦカードドライバ
５６　インタフェース（Ｉ／Ｆ）回路
５８　メニュー表示スイッチ（ＳＷ_ＭＤ）
６０　メニュー選択スイッチ（ＳＷ_Ｓ）
６２　メニュー確定スイッチ（ＳＷ_Ｋ）[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a so-called digital camera including a solid-state imaging device, for example, a CCD (charge-coupled device) imaging device.
[0002]
[Prior art]
In recent years, the progress of digital cameras has been remarkable, and they have become widely used together with personal computers. The main reason is that images taken by a digital camera can be taken into a personal computer, processed and stored as appropriate, and can be recorded as a hard copy by a printer if necessary. The major difference between a digital camera and a silver halide film camera is that in the former, a photographed image is recorded in a memory as a pixel signal for one frame, whereas in the latter, the photographed image is recorded on a film by a chemical change. It is in. In short, in the case of a digital camera, there is the convenience that pixel signals for one frame can be read out from the memory and appropriately processed. However, such convenience cannot be obtained at all with a silver halide film.
[0003]
[Problems to be solved by the invention]
By the way, in photographing during watching sports such as baseball and soccer, there is a demand to know, for example, the speed of a soccer ball or a car in a photographed image. However, when actually measuring the speed of the subject, it is necessary to install a dedicated speed measurement device and measure the speed at the same timing as when shooting, which is unrealistic and easily detects the speed of the subject I couldn't.
[0004]
Accordingly, it is an object of the present invention to provide a novel digital camera having a function of measuring the speed of a moving subject, utilizing the convenience of a digital camera that can perform signal processing of a captured image.
[0005]
[Means for Solving the Problems]
According to the digital camera of the present invention, a subject image formed on a light receiving surface of a solid-state image sensor at a predetermined photographing magnification by a photographing optical system is photoelectrically converted for a predetermined charge accumulation time and read out as a pixel signal for one frame. It is configured to generate a captured image based on pixel signals for one frame,
A speed measurement function is provided for measuring the speed of the moving subject based on the above-described shooting magnification and charge accumulation time when the shot image is captured as a measurement image including the moving subject.
[0006]
In the digital camera according to the present invention, the speed measurement function calculates an image blur area of the moving subject included in the measurement image from the measurement image, and calculates a width of the image blur area and a height thereof. The calculation unit includes a calculation unit that calculates the speed of the moving subject based on the width and height of the image blur area detected by the calculation unit, the above-described shooting magnification, and the charge accumulation time.
[0007]
According to the present invention, preferably, the extracting means performs the difference processing on the measurement image by using a background image corresponding to an image obtained by removing the moving subject from the measurement image, which is separately captured at the above-described imaging magnification and charge accumulation time. Thus, the image blur area of the moving subject is extracted from the measurement image.
[0008]
Further, according to the present invention, the extracting means detects the relative angular displacement and the relative translation between the background image and the measured image so as to spatially match one of the background image and the measured image with the other. May be included.
[0009]
In the digital camera according to the present invention, the photographing optical system can be configured as a zoom optical system. In this case, there are provided a focal length detecting means for detecting a focal length of the zoom optical system, and a focusing optical system position detecting means for detecting a position of the focusing optical system in the optical axis direction in the photographing optical system.
[0010]
In a preferred embodiment of the digital camera according to the present invention, monitor means for displaying a measurement image is provided, and the speed of the moving subject calculated by the calculation means is superimposed on the measurement image displayed by the monitor means. Paused.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a digital camera according to the present invention will be described with reference to the accompanying drawings.
[0012]
Referring to FIG. 1, a digital camera according to the present invention is schematically illustrated as a block diagram. The digital camera is provided with a system control circuit 10 for controlling the overall operation. The system control circuit 10 is composed of a microcomputer. This microcomputer temporarily stores a central processing unit (CPU), a program for executing various routines, a read-only memory (ROM) for storing constants and the like, and data. It includes a writable / readable memory (RAM) for storing and an input / output interface (I / O).
[0013]
The system control circuit 10 has a main switch (SW)_MWhen the main switch 12 is off, the system control circuit 10 is in the sleep mode. That is, when the digital camera is charged with a battery (not shown), the system control circuit 10 operates in the sleep mode (minimum power consumption state), and determines whether the main switch 12 is turned on only at a predetermined time interval. To monitor. When the main switch 12 is turned on, the mode shifts from the sleep mode to the operation mode, and the system control circuit 10 executes a switch operation monitoring processing routine as described later. That is, the system control circuit 10 monitors whether various switches described later are turned on, and when a predetermined switch is turned on, a process corresponding to the switch is executed by the system control circuit 10.
[0014]
The digital camera according to the present invention incorporates a zoom optical system 14 as a photographing optical system, and the zoom optical 14 employs a step zoom method in which a lens stop position is predetermined. In the present embodiment, for example, five steps of focal lengths are selected stepwise by a step zoom method from a so-called telephoto end to a wide end. For example, if the focal length at the telephoto end is f₁(Longest) and the focal length at the wide end is f₅(Shortest), three focal lengths f between them₂, F₃And f₄Is set (f₁> F₂> F₃> F₄> F₅). The photographing optical system 14 is driven by a zoom drive mechanism 16, and the zoom drive mechanism 16 incorporates an electric motor, for example, a stepping motor that is driven to rotate under the control of the system control circuit 10. By the rotational driving of such a drive motor, the focal length of the photographing optical system 14 is adjusted to the above-mentioned five focal lengths f.₁, F₂, F₃, F₄And f₅Is set to one of
[0015]
For the rotation drive control of the electric motor of the zoom drive mechanism 16, the system control circuit 10 controls the tele side switch (SW)._T) 18 and wide side switch (SW_W) 20. Each time the tele-side switch 18 is turned on, the drive motor of the zoom drive mechanism 16 is driven to rotate in the forward direction, whereby the focal length of the photographing optical system 14 is shifted stepwise toward the tele-end side. . For example, if the focal length of the photographing optical system 14 is f₄When the tele side switch 18 is turned on, the focal length of the photographing optical system 14 becomes f₄To f₃Move to On the other hand, each time the wide-side switch 20 is turned on, the drive motor of the zoom drive mechanism 16 is driven to rotate in the reverse direction, whereby the focal length of the photographing optical system 14 shifts stepwise toward the wide end. Let me do. For example, if the focal length of the photographing optical system 14 is f₃When the wide-side switch 20 is turned on, the focal length of the photographing optical system 14 becomes f₃To f₄Move to
[0016]
As shown in FIG. 1, a zoom encoder 22 is incorporated in the photographing optical system 14, and focal length data set by the photographing optical system 14 is output to the system control circuit 10 by the zoom encoder 22. In other words, the system control circuit 10 captures the focal length data output from the zoom encoder 22 to obtain the five focal lengths f described above.₁, F₂, F₃, F₄And f₅Can be identified as having been set by the photographing optical system 14. Further, the focal length data is used for calculating the photographing magnification M by the system control circuit 10 as described later.
[0017]
Further, in the present embodiment, the photographing optical system 14 employs an automatic focusing method. That is, the focusing lens included in the photographing optical system 14 is driven by the focusing lens driving mechanism 24, whereby the subject image is automatically focused. That is, similarly to the case of the zoom drive mechanism 16, the focusing lens drive mechanism 24 also incorporates an electric motor, such as a stepping motor, which is driven to rotate under the control of the system control circuit 10, and this electric motor will be described later. By rotating in such a manner as described above, the focusing lens of the photographing optical system 14 is driven to automatically focus the subject image.
[0018]
The system control circuit 10 includes a recording / reproducing switch (R / P @ SW) 26. The recording / reproducing switch 26 is configured as a slide switch that can slide between the recording side and the reproducing side. That is, when the recording / reproduction switch 26 is slid to the recording side, the recording (photographing) mode is selected as the operation mode, and when the recording / reproduction switch 26 is slid to the reproduction side, the reproduction mode is selected as the operation mode. The recording mode and the reproduction mode will be described later in detail.
[0019]
The system control circuit 10 further includes a photometric switch (SW)._P) 28 and release switch (SW_R) 20, the operation of these switches 28 and 30 is effective only when the recording mode is selected by the recording / reproduction switch 26, and is invalid when the reproduction mode is selected by the recording / reproduction switch 26. The photometric switch 28 and the release switch 30 are operated by a common release button (not shown). That is, when the release button is half-pressed, the photometric switch 28 is turned on, and when the release button is fully pressed, the release switch 30 is turned on. As will be described later, when the photometric switch 28 is turned on, a photometric process is performed, and when the release switch 30 is turned on, a photographing process is performed.
[0020]
The photographing optical system 14 is combined with a solid-state imaging device, for example, a CCD (charge-coupled device) imaging device 32, and an optical low-pass filter 34 is provided on a light receiving surface of the CCD imaging device 32. In addition, the digital camera is capable of performing full-color photographing. For this reason, a color filter (not shown) is interposed between the light receiving surface of the CCD image sensor 32 and the optical low-pass filter 34. A subject image captured by the photographing optical system 14 is formed on a light receiving surface of the CCD image pickup device 32 through an optical low-pass filter 34, and the optical subject image is photoelectrically converted into a color pixel signal for one frame.
[0021]
Color pixel signals are sequentially read from the CCD image sensor 32, and the reading is performed according to a read clock pulse output from the CCD drive circuit 36 to the CCD image sensor 32. When the recording mode is selected by the recording / reproducing switch 26 and the release switch 30 is turned off, the reading of the color pixel signals from the CCD image sensor 32 is appropriately thinned out. That is, the number of pixels smaller than the actual number of pixels of the CCD image sensor 32 is read out from the CCD image sensor 32 as a color pixel signal for one frame. On the other hand, immediately after the release switch 30 is turned on when the recording mode is selected by the recording / reproducing switch 26, all the color pixel signals for one frame are read out from the CCD image sensor 32 once without being thinned out for photographing and recording.
[0022]
Such reading is performed by switching the read clock pulse from the CCD drive circuit 36. That is, the CCD drive circuit 36 is operated under the control of the system control circuit 10, and normally, a thinning-out read clock pulse for thinning out and reading out color pixel signals from the CCD image pickup device 32 is output. Immediately after the release switch 30 is turned on, an imaging read clock pulse is output. When all the color pixel signals for one frame are read out from the CCD image pickup device 32 without being thinned out in accordance with the photographing readout clock pulse, the thinning-out readout clock pulse is output from the CCD drive circuit 36 again.
[0023]
The color pixel signals sequentially read from the CCD image sensor 32 are input to an amplifier (AMP) 40 through a noise reduction circuit, ie, a correlated double sampling circuit (CDS) 38, where they are amplified with an appropriate gain. Next, the color pixel signal is input to an analog / digital (A / D) converter 42, where it is converted into a digital color image signal and then taken into the system control circuit 10.
[0024]
In the present embodiment, when the recording mode is selected by the recording / reproducing switch 26, the image captured by the photographing optical system 14 is monitored as a moving image. A VRAM 44, a digital / analog (D / A) converter 46, a video encoder 48, and a liquid crystal display (LCD) panel 50 are provided. Further, in order to monitor the image captured by the imaging optical system 14 as a moving image, the reading of the thinned pixel signals for one frame from the CCD image sensor 32 is repeated every predetermined time. For example, when the NTSC method is adopted, the reading of the thinned pixel signals for one frame is repeated 30 times per second.
[0025]
The thinned-out digital color pixel signal received from the A / D converter 42 by the system control circuit 10 is subjected to appropriate image processing, for example, white balance processing, gamma correction processing, and the like, and then converted into a luminance signal and two color difference signals. The luminance signal and the color difference signal are temporarily written into a dynamic RAM (DRAM) 52 once. When the writing of the luminance signal and the color difference signal in the DRAM 52 reaches one frame, the luminance signal and the color difference signal for one frame are read from the DRAM 52 and written in the VRAM 44. Next, the luminance signal and the color difference signal are sequentially read from the VRAM 44 and input to the D / A converter 46, where they are converted into an analog luminance signal and an analog color difference signal. Subsequently, the analog luminance signal and the analog color difference signal are input to a video encoder 48, where they are converted into appropriate video signals and input to a liquid crystal display (LCD) panel 50. Thus, the subject image captured by the imaging optical system 14 is displayed as a moving image on the LCD panel 50 according to the video signal.
[0026]
When the subject image captured by the photographing optical system 14 is displayed as a moving image on the LCD panel 50, the charge accumulation time when the CCD image sensor 32 obtains one frame of color pixel signals is appropriately set as a fixed time. However, the gain of the amplifier 40 is adjusted in order to keep the brightness of the moving image display on the LCD panel 50 constant. That is, the average luminance value of the luminance signal for one frame obtained from the thinned color pixel signal for each frame is compared with the reference value, and the gain of the amplifier 40 is adjusted so that the difference between them is eliminated. Irrespective of the brightness of the moving image, the brightness of the moving image display on the LCD panel 50 can be kept constant.
[0027]
The luminance signal for one frame obtained from the thinned color pixel signals for each frame is also used for operating the focusing lens driving mechanism 24. That is, in the present embodiment, the automatic focusing of the photographing optical system 14 is controlled based on a so-called contrast method. That is, the system control circuit 10 calculates the luminance difference between the pixels adjacent to each other in at least a part of the subject image formed on the light receiving surface of the CCD image sensor 32 so that the contrast of the region becomes maximum. Then, the focusing lens driving mechanism 24 is driven and controlled to perform focusing control of the focusing lens of the photographing optical system 14. Thus, moving image display on the LCD panel 50 is always performed in focus. The system control circuit 10 also knows the current position of the focusing lens of the photographing optical system 14 as a lens extension from the lens position where the focusing lens of the photographing optical system 14 focuses on infinity. The photographing magnification M is calculated from the feeding amount and the above-mentioned focal length data. In the present embodiment, the shooting magnification M is obtained by an arithmetic expression M = f / D (where f is a focal length and D is a subject distance), and the subject distance D is not shown from the detected lens extension amount. Determined by referring to the table.
[0028]
Further, the luminance signal for one frame obtained from the thinned-out color pixel signals for each frame is also used as a photometric value to obtain an optimal exposure when a still image is taken. That is, when the photometric switch 28 is turned on when the recording mode is selected by the recording / reproducing switch 26, the luminance signal for one frame is processed as the luminance value (brightness) of the subject, and the CCD image pickup device at the time of photographing the subject The charge accumulation time for 32 is calculated based on the brightness value, so that when the release switch 30 is turned on, the subject is photographed as a still image by the CCD image sensor 32 with optimal exposure.
[0029]
As described above, immediately after the release switch 30 is turned on (that is, after the lapse of the charge accumulation time), the output of the read clock pulse from the CCD drive circuit 36 is switched from the thinning read clock pulse to the photographing read clock pulse. Thereby, all the color pixel signals for one frame are read from the CCD image pickup device 32 without being thinned out. Similarly to the case where the color pixel signals for one frame are thinned out and read, the color pixel signals without thinning for one frame are also input to the amplifier (AMP) 40 through the correlated double sampling circuit (noise reduction circuit) 38. Then, after being amplified with an appropriate gain, the analog / digital (A / D) converter 42 converts the image into a digital color image signal without decimation for one frame and takes it into the system control circuit 10.
[0030]
As in the case of the thinned digital color pixel signal, the digital color image signal without thinning is subjected to image processing such as white balance processing and gamma correction processing by the system control circuit 10 and then stored as still image data by an appropriate storage means. Is done. In the present embodiment, a CF card memory 53 (flash memory) is used for storing still image data, and this CF card memory is removably loaded in a CF card driver 54. As shown in FIG. 1, the CF card driver 54 is connected to the system control circuit 10 via an interface (I / F) circuit 56. In short, the still image data is written and stored in the CF card memory 53 via the interface (I / F) circuit 56 and the CF card driver 54.
[0031]
When the reproduction mode is selected by the recording / reproduction switch 26, a captured image can be displayed on the LCD panel 50 based on the still image data stored in the CF card memory. In this case, predetermined one frame of still image data is read out from the CF card memory, subjected to appropriate thinning processing, and then written into the VRAM 44, whereby the captured image can be monitored on the LCD panel 50. It is.
[0032]
The system control circuit 10 further includes a menu display switch (SW_MD) 58, menu selection switch (SW_S) 60 and menu confirmation switch (SW_K) 62 is provided. When the menu display switch 58 is operated, the display on the LCD panel 50 is switched to a menu display screen, and one of the menus is highlighted by a highlight cursor. The menu selection switch 60 is configured as a cross switch, and by operating the cross switch 60, the reverse cursor is shifted up, down, left, and right, thereby selecting a desired menu. When the menu selection switch 62 is operated after the desired menu is selected by operating the menu selection switch 60, the processing corresponding to the selected menu is executed by the system controller 10 and the display on the LCD panel 50 is also executed. It switches according to.
[0033]
The menu selection switch 60 and the menu confirmation switch 62 are not only used when the menu display screen is displayed on the LCD panel 50 by operating the menu display switch 58, but the menu is displayed on the display screen of the LCD panel 50. Are used to select and confirm those menus.
[0034]
The digital camera described above has a function of measuring the speed of a moving subject according to the present invention, and the principle of such speed measurement will be described below.
[0035]
First, a specific place through which a moving subject should pass is photographed as a background image by the above digital camera, and the background image is exemplarily shown in FIG. As the background image, an image of an immovable (still) object whose shape is easily extracted in later image processing, for example, a structure such as a building or a wall is selected, and trees may be used if there is no wind. As shown in FIG. 2, a target TG is imprinted on the background image, and the target TG remains set at a predetermined position until the measurement of the speed of the moving subject ends. In the present embodiment, the target TG is formed of a plate-like member painted in jet black, and has two small circular reflection regions R on its surface.₁And R₂Is formed. For example, a small circular reflection region (R₁, R₂Is obtained by attaching an aluminum foil piece of an appropriate size to the surface of the target TG.
[0036]
After the background image is captured, the moving subject is photographed together with the background image, and the moving subject may be, for example, a thrown baseball. As exemplarily shown in FIG. 3, such a moving subject, that is, a baseball is photographed as an image blur area (shaded area) BR due to high speed. The length of the image blur area BR indicates the speed of the baseball, and the speed can be calculated by an algorithm described later. For the sake of convenience in the following description, a captured image obtained by capturing a moving subject together with a background image will be referred to as a measurement image.
[0037]
To calculate the length of the image blur region BR, the image blur region BR is extracted from the measurement image (FIG. 3). In other words, the background image is removed while leaving only the image blur region BR from the measurement image. In such processing, the individual pixel signals forming the background image in FIG. 2 and the individual pixel signals forming the background image in FIG. 3 are compared with each other in correspondence with each other. , The pixel signal on the measurement image (FIG. 3) side is removed from the measurement image as not included in the image blur region BR. On the other hand, when the difference between the two luminance values is significantly different, that is, when the difference is out of the above-mentioned predetermined minute range, the pixel signal on the measurement image (FIG. 3) side is included in the image blur region BR and included in the measurement image. Will be left. In short, the image blur area of the moving subject is extracted from the measurement image by performing the difference processing on the measurement image with the background image.
[0038]
As shown in FIG. 2, an XY coordinate system is set along two directions of a horizontal direction and a vertical direction of the background image in order to specify the position of each pixel signal on the background image. Is located at the lower left corner of the background image, and its X and Y axes respectively extend along the bottom and left sides of the background image. On the other hand, as shown in FIG. 3, a similar XY coordinate system is set for the measurement image in order to specify the position of each pixel signal on the measurement image. In this embodiment, since the background image and the measurement image are both taken with the digital camera held in hand, the measurement image may be inclined with respect to the background image taken earlier. In order to associate the individual pixel signals on the background image with the individual pixel signals on the measurement image, one of the background image and the measurement image is relatively centered on the coordinate origin 0 with respect to the other. It is necessary to make the position of the background image coincide with the position of the measurement image with respect to the XY coordinate system by moving.
[0039]
Referring to FIG. 4, there is shown a background image in which the background image is moved with respect to the measurement image so that both positions are coincident with the XY coordinate system, and this background image is referred to as a position-corrected background image. To
[0040]
In order to obtain a position-corrected background image as shown in FIG. 4, two small circular reflection areas R on the target TG of the background image (FIG. 2)₁And R₂Center coordinates P of₁(X₁, Y₁) And P₂(X₂, Y₂) Are obtained by image processing such as labeling processing, and two small circular reflection areas R on the target TG of the measurement image (FIG. 3).₁And R₂Center coordinates Q of₁(U₁, V₁) And Q₂(U₂, V₂Is obtained by image processing such as labeling processing. At this time, the direction vector (x) of each of the background image (FIG. 2) and the measurement image (FIG. 3)_e,
y_e) And (u)_e, V_e) Can be expressed by the following equation.
(Equation 1)

[0041]
In order to obtain a position-corrected background image (FIG. 4) from the background image (FIG. 2), the background image is parallel to a rotation angle θ and an XY coordinate system that rotate the background image around the XY coordinate origin. The translation amount (Δx, Δy) for the movement can be expressed as follows.
θ = sin^-1(U_ey_e-V_ex_e)
Δx = x₁-U₁
Δy = y₁-V₁
[0042]
That is, the coordinates P of an arbitrary pixel signal of the position-corrected background image (FIG. 4)_i(X_i, Y_i), The coordinates P_i(X_i, Y_i), The coordinates P of the pixel signal on the original background image (FIG. 2)_org(X_org, Y_org) Can be expressed by the following equation.
x_org= (X_i-U_i) Cos θ-(y_i-V_i) Sin θ + Δx
y_org= (X_i-U_i) Sin θ + (y_i-V_i) Cosθ + Δy
[0043]
The coordinates P on the position correction background image (FIG. 4)_i(X_i, Y_i) Correspond to the pixel signals on the measured image (FIG. 3). Therefore, the coordinates P_i(X_i, Y_i) And the coordinates P on the background image (FIG. 2)._org(X_org, Y_org) Correspond to each other, so that when the difference between the brightness values is substantially equal, that is, when the difference is included in a predetermined minute range, the coordinates P on the measurement image (FIG. 3)_i(X_i, Y_i) Is removed from the measurement image as not included in the image blur region BR. On the other hand, when the difference between the two brightness values is significantly different, that is, when the difference is outside the above-described predetermined minute range, the coordinates P on the measurement image (FIG. 3) side_i(X_i, Y_i) Is left in the measurement image as being included in the image blur region BR.
[0044]
By repeating such processing, the background image is removed from the measurement image (2), and only the image blur region BR is extracted as shown in FIG. Next, as shown in FIG. 6, the width W of the image blur region BR_CAnd its height H_CIs determined by image processing. Then, the ball speed S_BIs calculated by the following equation.
S_B= (W_C-H_C) / MT_C
Here, “M” is the photographing magnification of the measured image, and “T”_C"" Is the charge accumulation time of the measured image (FIG. 3).
[0045]
Referring to FIG. 7, the main switch (SW)_M2) shows a flowchart of an initialization routine executed only once by the system control circuit 10 immediately after the switch 12 is turned on.
[0046]
In step 701, it is determined whether any of the recording mode and the reproduction mode has been selected. That is, when the main switch 12 is turned on, for example, if the recording / reproducing switch (R / P @ SW) 26 is on the recording side, the recording mode is selected. Is done. On the other hand, if the recording / reproduction switch (R / P @ SW) 26 is on the reproduction side when the main switch 12 is turned on, the process proceeds to step 703, where an instruction to start execution of the reproduction processing routine is issued. The photographing processing routine is executed when photographing a subject using the digital camera, and the reproduction processing routine is executed when monitoring a photographed image on the LCD panel 50. The processing routine will be described later in detail with reference to FIG. 10, and the reproduction processing routine will be described later in detail with reference to FIGS.
[0047]
In step 704, the flags BFK and SMF are initialized to "0". The flag BKF is a flag for indicating whether or not a background image photographing mode for photographing a subject as a background image (FIG. 2) used for speed measurement in the recording mode is selected. When BKF = 1 When BKF = 0, it is instructed that the selection of the background image shooting mode has been released. The flag SMF is a flag for instructing whether or not the speed measurement mode is selected in the reproduction mode. When SMF = 1, it is instructed that the speed measurement mode is selected. At this time, it is instructed that the selection of the speed measurement mode has been released. In step 705, other initialization processing is executed, but these initialization processing itself is not directly related to the present invention.
[0048]
8 and 9, there is shown a flowchart of a switch operation monitoring routine executed by the system control circuit 10. The execution of the switch operation monitoring processing routine is started after the execution of the initialization routine of FIG. 7 is completed.
[0049]
In step 801, it is monitored whether or not the recording / reproducing switch (R / P @ SW) 26 has been operated. If the operation of the recording / reproducing switch 26 has been confirmed, the process proceeds to step 802, where a recording mode has been selected. It is determined whether or not. When it is confirmed that the recording mode has been selected by operating the recording / reproducing switch 26, the process proceeds to step 803, where an instruction to stop execution of the reproducing process routine is issued, and then proceeds to step 804, where execution of the photographing process routine is started. Is commanded. On the other hand, if it is confirmed in step 802 that the reproduction mode has been selected, the process proceeds to step 805, where an instruction to stop the execution of the photographing process routine is issued, and then to step 806, where an instruction to start execution of the playback process routine is issued. You.
[0050]
When the operation of the recording / reproduction switch 26 is not confirmed in step 801, or after the execution start instruction of the photographing processing routine (step 804) or after the execution start instruction of the reproduction processing routine (step 806), the process proceeds to step 807. Then, the menu display switch (SW_MD) 58 is monitored to see if it has been operated; When the operation of the menu display switch 58 is confirmed (that is, when the display on the LCD panel 50 is switched to the menu display screen), the process proceeds to step 808, where the processing being executed is interrupted. That is, for example, if the photographing processing routine is being executed, the execution of the photographing processing routine is interrupted, and if the reproducing processing routine is being executed, the execution of the reproducing processing routine is interrupted.
[0051]
At step 809, a menu selection switch (SW_SThe menu display processing is executed in accordance with the operation 60). That is, in the menu display processing, the reverse cursor is shifted by operating the menu selection switch (cross switch) 60. At step 810, a menu confirmation switch (SW_K) It is monitored whether 62 has been operated. In short, until the operation of the menu confirmation switch 62 is confirmed, the menu display process is continued according to the operation of the menu selection switch 60, and a desired menu is selected.
[0052]
When the operation of the menu confirmation switch 62 is confirmed in step 810, that is, when the selection menu is confirmed, the process proceeds to step 811 to determine whether the selection menu is the speed measurement menu. If the speed measurement menu has been selected, the process proceeds to step 812, where "1" is given to the flag SMF, thereby indicating that the speed measurement mode has been selected. If the selected menu is not the background image shooting menu, the process proceeds from step 811 to step 813, where it is determined whether or not the selected menu is the speed measurement release menu. If the speed measurement release menu is selected, the process proceeds to step 814, where "0" is given to the flag SMF, thereby indicating that the selection of the speed measurement mode has been released.
[0053]
If the selected menu is neither the speed measurement menu nor the speed measurement release menu, the process proceeds from step 813 to step 815, where it is determined whether the selected menu is a background image shooting menu. If the background image shooting menu is selected, the process proceeds to step 816, where "1" is given to the flag BKF, thereby indicating that the background image shooting mode has been selected. If the selected menu is not the background image shooting menu, the process proceeds from step 815 to step 817, where it is determined whether the selected menu is the background image shooting canceling menu. If the release menu has been selected, the process proceeds to step 818, where "0" is given to the flag BKF, thereby indicating that the selection of the background image shooting mode has been released.
[0054]
When the selection menu is neither the background image shooting menu nor the background image shooting cancel menu, the process proceeds from step 817 to step 819, where processing according to the other menu determined by operating the menu determination switch 62 is executed. It should be noted that such a selection menu itself is not directly related to the present invention, and a description thereof will be omitted.
[0055]
Thereafter, the process proceeds to step 820, where the interrupted process (808) is restarted. Next, in step 821, it is determined whether or not the main switch 12 is turned off. If the main switch 12 is on, the process returns to step 801 to monitor the operation of the recording / reproduction switch 26 and the menu display switch 58. . On the other hand, if the main switch 12 is off in step 821, the process proceeds to step 822, where the mode is shifted to the sleep mode, and the present routine ends.
[0056]
Referring to FIG. 10, there is shown a flowchart of the photographing processing routine, and the execution start command of the photographing processing routine is, as described above, the step 702 of the initialization routine (FIG. 7) or the switch operation monitoring processing routine (FIG. 8 and FIG. This is performed in step 804 of 9).
[0057]
In step 1001, an LCD panel display processing routine is executed. Such an LCD panel display processing routine itself is well known in a conventional digital camera, and by executing the LCD panel display processing routine, a subject image is displayed as a moving image on the LCD panel 48 in the manner described above. That is, thinned color pixel signals for one frame are sequentially read from the CCD image sensor 32 at predetermined time intervals, and a subject image is displayed as a moving image on the LCD panel 50 based on the thinned color pixel signals. During execution of the LCD panel display processing routine, the focusing lens mechanism 24 is driven in accordance with the above-described contrast method every time a thinned-out color pixel signal for one frame is read from the CCD image sensor 32. The moving image display on the LCD panel 50 is always performed in focus.
[0058]
In step 1002, a zoom processing routine is executed. Such a zoom processing routine itself is well known in a conventional digital camera. That is, in the zoom processing routine, the tele side switch (SW_T) 18 and wide side switch (SW_w20) is monitored, and when one of these two switches is operated, the zoom drive mechanism 16 is driven and the focal length of the photographing optical system 14 becomes f₁, F₂, F₃, F₄And f₅Is set to one of
[0059]
In step 1003, the photometry switch (SW) is pressed by half-pressing the release switch button._P) 28 is turned on. If the photometry switch 28 is off, the process returns to step 1002. In short, while the subject image captured by the photographing optical system 14 is displayed as a moving image on the LCD panel 50, the on operation of the photometric switch 28 is monitored in step 1003.
[0060]
When the on operation of the photometric switch 28 is confirmed in step 1003, the process proceeds to step 1004, where a photometric process is executed. In the photometric processing, an optimal exposure value is obtained based on an average luminance value (photometric value) of a luminance signal for one frame obtained from a thinned color pixel signal for one frame read from the CCD image sensor 32. Next, in step 1005, the focusing lens mechanism 24 is driven in accordance with the above-described contrast method, whereby focusing processing immediately before the photographing operation is performed.
[0061]
In step 1006, the focal length data is fetched from the zoom encoder 22, and the focal length (f₁, F₂, F₃, F₄, F₅) Is recognized by the focal length data. Next, in step 1007, the subject distance is calculated based on the focal length data, and subsequently, in step 1008, the shooting magnification M is calculated.
[0062]
In step 1009, based on the optimal exposure value obtained in step 1004, the charge accumulation time T_CIs calculated. Next, in step 1010, the release switch (SW) is pressed by fully pressing the release switch button._RIt is monitored whether or not 30) is turned on. If the release switch 30 is off, the process returns to step 1001. If the ON state of the photometry switch 28 is maintained, the processing immediately before photographing in steps 1004 to 1009 is repeated.
[0063]
If it is confirmed in step 1010 that the release switch 30 is turned on, the process proceeds to step 1011, where unnecessary charges are swept out of the CCD image sensor 32. Next, in step 1012, the charge accumulation time T_CIs monitored. Charge accumulation time T_CWhen the progress is confirmed, the process proceeds to step 1013, where all the color pixel signals for one frame are read out from the CCD image pickup device 32 without being thinned out. The signal is taken into the system control circuit 10 as a digital color pixel signal for one frame via the amplifier 38, the amplifier 40 and the A / D converter 42.
[0064]
The digital color pixel signals for one frame are subjected to image processing such as white balance processing and gamma correction processing to generate still image data (step 1014). Next, at step 1015, it is determined whether or not the speed measurement mode is selected. When the speed measurement mode is selected (SMF = 1), the process proceeds to step 1016, where the still image data is transferred to the predetermined memory area of the CF card memory 53 via the interface (I / F) circuit 56 and the CF card driver 54. Is written according to a predetermined format. At this time, the photographing magnification data (M) and the charge accumulation time data (T_C) And flag data (BKF) are also stored in the header of the memory area. That is, when the speed measurement mode is selected, the photographing magnification data (M) and the charge accumulation time data (T) are stored in the CF card memory 53 together with the still image data._C) And flag data (BKF) so that the still image data can be determined based on the flag data (BKF) as either background image data (BFF = 1) or measurement image data (BFF = 0). Is done.
[0065]
In step 1017, the header area of the FC card memory 53 is searched to determine whether there is at least one background image with the flag data BFF = 1 and one or more measurement images with the flag data BKF = 0. If there is both the background image and the measured image, the process jumps to step 1102 of the reproduction processing routine shown in FIGS. 11 and 12, and immediately shifts to the speed measurement operation in the reproduction mode. The speed measurement operation will be described later in detail with reference to FIGS. When photographing is performed for the purpose of speed measurement, a pair of background image and measurement image required for speed measurement are often photographed at relatively close time intervals. In addition, there is a high frequency of photographing one of the measurement image and the background image and then photographing the other. In addition, since the background image can be shared for each measurement image photographed on the same background with the same background, in many cases, a plurality of images to be measured are photographed first, and then one background image is photographed last ( The priority of the photographing is higher for the measurement image because of the photo opportunity.) Therefore, according to the above configuration, when the background image is captured at the end and the speed measurement condition is satisfied, the process immediately shifts to the speed measurement process in the playback mode. You will be free from the hassle of changing to.
[0066]
On the other hand, if the speed measurement mode has not been selected in step 1015 (flag SMF = 0), that is, if normal shooting has been performed, the process proceeds from step 1015 to step 1019, where the still image data is transferred to the interface (I / I / O). F) The data is written into a predetermined memory area of the CF card memory 53 via the circuit 56 and the CF card driver 54 according to a predetermined format. At this time, the photographing magnification data M and the flag data ( BKF) is not recorded.
[0067]
Referring to FIGS. 11 and 12, there is shown a flowchart of the reproduction processing routine. As described above, the execution start command of this reproduction processing routine is executed at step 703 of the initialization routine (FIG. 7) or the switch operation monitoring processing routine (FIG. 7). 8 and FIG. 9).
[0068]
In step 1101, it is determined whether the flag SMF is "1" or "0". When SMF = 0, that is, when the selection of the speed measurement mode is cancelled, the process proceeds to step 1102, where the normal reproduction process is executed. The normal reproduction process is a process for monitoring the captured image on the LCD panel 50 according to a predetermined procedure based on the still image data stored in the CF card memory. Such a reproduction process itself is performed by a conventional digital camera. It is what is being done. A selection menu of the speed measurement mode is displayed on the playback screen of the captured image on the LCD panel 50, and the speed measurement mode is set by a menu selection switch (SW)._S) After selecting with 60, the menu confirmation switch (SW_K) 62, the flag SMF is rewritten from "0" to "1".
[0069]
When SMF = 1 in step 1101, that is, when the speed measurement monitor is selected, the process proceeds to step 1103, where the background image (FIG. 2) is searched. That is, the still image data in which the flag data (BKF) is given “1” is searched from the still image data stored in the CF card memory. Next, in step 1104, the search result of the background image is determined. That is, when the background image is included in the CF card memory, the process proceeds to step 1105, where the background image (FIG. 2) is displayed on the LCD panel 50. That is, the still image data with BKF = 1, that is, the background image data is thinned out from the CF card memory and read out, a display video signal is created from the thinned background image data, and the background image is generated based on the video signal. Is displayed on the LCD panel 50. When there are a plurality of background images, it is preferable to display the number on the LCD panel 50.
[0070]
In step 1106, display switching processing of the background image is performed in accordance with the operation of the menu selection switch 60, and then in step 1107, it is determined whether or not the menu determination switch 62 has been operated. If the operation of the menu confirmation switch 62 is not confirmed, the process returns to step 1106. In short, until the menu determination switch 62 is operated, the display of the background image is switched according to the operation of the menu selection switch 60, whereby the background image is selected. When the operation of the menu confirmation switch 62 is confirmed in step 1107, that is, when the selection of the background image is confirmed, the process proceeds to step 1108, where one frame of still image data corresponding to the confirmed background image is thinned out. Without being read from the CF card memory and temporarily stored in the DRAM 52.
[0071]
In step 1109, a search for a measurement image (FIG. 3) is performed. That is, the still image data in which the flag data (BKF) is given “0” is searched from the still image data stored in the CF card memory. Next, in step 1110, a search result of the measurement image is determined. That is, when the measured image is included in the CF card memory, the process proceeds to step 1110, where the measured image (FIG. 3) is displayed on the LCD panel 50. That is, the still image data with BKF = 0, that is, the measured image data, is thinned out from the CF card memory and read out, a display video signal is created from the thinned measured image data, and the background image is generated based on the video signal. Is displayed on the LCD panel 50. When there are a plurality of measurement images, it is preferable to display the number on the LCD panel 50.
[0072]
In step 1112, display switching processing of the measurement image is performed in accordance with the operation of the menu selection switch 60, and then, in step 1113, it is determined whether the menu determination switch 62 has been operated. If the operation of the menu confirmation switch 62 is not confirmed, the process returns to step 1112. In short, until the menu confirmation switch 62 is operated, the display of the measurement image is switched according to the operation of the menu selection switch 60, whereby the measurement image is selected. When the operation of the menu confirmation switch 62 is confirmed in step 1113, that is, when the selection of the measurement image is confirmed, the process proceeds to step 1114, where one frame of still image data corresponding to the confirmed measurement image is thinned out. Without being read from the CF card memory and temporarily stored in the DRAM 52.
[0073]
In step 1115, it is determined whether or not the imaging magnification (M) of the confirmed background image (step 1108) matches the imaging magnification (M) of the confirmed measurement image (step 1114). If the photographing magnifications of both images do not match, the process proceeds to step 1116, where a warning display is displayed on the LCD panel 50 indicating that speed measurement is not possible due to the photographing magnification mismatch, and then the process returns to step 1112. That is, selection of another measurement image is prompted.
[0074]
When it is confirmed in step 1115 that the photographing magnification (M) of the confirmed background image and the confirmed measurement image match, the process proceeds to step 1117, where the small circular reflection area R of the target TG is extracted from the background image (FIG. 2).₁And R₂Center coordinates P of₁(X₁, Y₁) And P₂(X₂, Y₂) Are obtained by image processing such as labeling processing, and two small circular reflection areas R of the target TG are obtained from the measurement image (FIG. 3).₁And R₂Center coordinates Q of₁(U₁, V₁) And Q₂(U₂, V₂) Are obtained by image processing such as labeling processing, and the direction vectors (x_e, Y_e) And (u)_e, V_e) Is calculated based on the following equation.
(Equation 2)

[0075]
In step 1118, the rotation angle θ of the background image (FIG. 2) with respect to the measurement image (FIG. 3) is obtained by the following calculation.
θ ← sin^-1(U_ey_e-V_ex_e)
[0076]
In step 1119, the translation amount (Δx, Δy) of the background image (FIG. 2) with respect to the measurement image (FIG. 3) is obtained by the following calculation.
Δx ← x₁-U₁
Δy ← y₁-V₁
[0077]
In step 1120, a position-corrected background image (FIG. 4) is generated based on the rotation angle θ and the translation amount (Δx, Δy), and then in step 1121, the measured image (FIG. The image blur area BR of the moving subject is extracted by performing the difference processing in 4). Subsequently, in step 1122, the width W of the image blur area BR_CAnd its height H_CIs obtained by image processing, and in step 1123, the speed S of the moving subject_BIs obtained by the following calculation.
S_B= (W_C-H_C) / MT_C
Of course, here, “M” is the photographing magnification of the measurement image (or background image), and “T”_C"" Is the charge accumulation time of the measured image.
[0078]
In step 1124, the speed S of the moving subject calculated as described above is calculated._BIs spar-imposed on the measurement image displayed on the LCD panel 50 as exemplarily shown in FIG. That is, in the example shown in the figure, 95 km is spur imposed on the measurement image as the speed of the moving object, that is, the ball. Thus, the user of the digital camera can recognize the speed of the moving subject in the measurement image displayed on the LCD panel 50.
[0079]
In step 1125, the menu selection processing of the measurement image is executed in accordance with the operation of the menu selection switch 60. Next, in step 1125, it is determined whether the menu confirmation switch 62 has been operated. If the operation of the menu confirmation switch 62 is not confirmed, the process returns to step 1112. In short, until the menu confirmation switch 62 is operated, the menu selection process on the measurement image is executed according to the operation of the menu selection switch 60. More specifically, as shown in FIG. 13, “Change 1”, “Change 2”, and “End” are displayed as menus on the measurement screen. In the example shown in FIG. 13, “Change 1” is highlighted by a reverse cursor. Is displayed. The reverse cursor is shifted among three menus, that is, "change 1", "change 2", and "end" by operating the menu selection switch 60, and the menu of the reverse display is selected.
[0080]
Here, "change 1" means change of the measurement image, "change 2" means change of the background image, and "end" means release of the speed measurement mode selection.
[0081]
When the menu confirmation switch 62 is operated in step 1126, the process proceeds to step 1127, where it is determined whether or not the selected menu is "change 1". That is, it is determined whether or not the change of the measurement image is selected. When the change of the measurement image is selected, the process returns to step 1112, the display switching process of the measurement image is performed, and when a new measurement image is selected (step 1113), the movement transferred to the new measurement image is performed. The calculation of the speed of the subject is performed in the manner described above.
[0082]
When the selection menu is not "change 1", that is, when the measurement image is not changed, the process proceeds from step 1127 to step 1128, where it is determined whether or not the selection menu is "change 2". That is, it is determined whether the change of the background image has been selected. When the change of the background image is selected, the process returns to step 1106, the display switching process of the background image is performed, and when a new background image is selected (step 1107), the measurement image for the new background image is appropriately changed. The selected object is selected (steps 1112 and 1113), and thereafter, the speed calculation of the moving subject shown in the measurement image is performed in the above-described manner.
[0083]
If the selection menu is neither "change 1" nor "change 2", that is, if "end" is selected, the process proceeds to step 1129, where the flag SMF is rewritten from "1" to "0" and then step 1101 is performed. Then, the normal reproduction process (step 1102) is executed.
[0084]
In the above-described embodiment, it is assumed that the background image and the measurement image are both taken with the digital camera held in hand, but the background image and the measurement image are taken with the digital camera fixed on a tripod. In this case, the process of generating the position-corrected background image for matching the background image with the measurement image can be omitted. That is, the image blur area of the moving subject can be immediately extracted from the background image and the measurement image.
[0085]
In the above-described embodiment, the speed calculation of the moving subject is performed in the image playback mode after the background image and the measurement image are stored in the CF card memory. However, the speed calculation process may be performed in real time. It is. That is, for example, an image photographed at a certain point in time is designated as a background image, an image obtained in subsequent photographing is set as a measurement image, and the speed of the moving object is measured every time each measurement image is photographed. It may be.
[0086]
【The invention's effect】
As is apparent from the above description, the digital camera according to the present invention is provided with a function of measuring the speed of a moving subject in addition to a photographing function, so that not only the commercial value is enhanced, but also a new demand for the digital camera is generated. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing an embodiment of a digital camera according to the present invention.
FIG. 2 is a schematic diagram exemplarily showing a background image used for speed measurement according to the present invention.
FIG. 3 is a schematic view exemplarily showing a measurement image used for speed measurement according to the present invention.
4 is a schematic diagram showing a position-corrected background image whose position has been corrected so that the background image of FIG. 2 spatially matches the measured image of FIG. 3;
5 is a schematic diagram illustrating an image blur area of a moving subject extracted from the measurement image of FIG. 3 and the position-corrected background image of FIG. 4;
6 is an enlarged view showing the image blur area of the moving subject shown in FIG. 5 in an enlarged manner, showing the dimensions required for measuring the speed of the moving subject.
FIG. 7 is a flowchart of an initialization routine executed by the system control circuit shown in FIG. 1;
FIG. 8 is a part of a flowchart of a switch operation monitoring processing routine executed by the system control circuit shown in FIG. 1;
FIG. 9 is the remaining part of the flowchart of the switch operation monitoring processing routine shown in FIG. 8;
FIG. 10 is a flowchart of a photographing processing routine executed by the system control circuit shown in FIG. 1;
FIG. 11 is a part of a flowchart of a reproduction processing routine executed by the system control circuit shown in FIG. 1;
FIG. 12 is a remaining part of the flowchart of the reproduction processing routine shown in FIG. 8;
FIG. 13 is a schematic view exemplarily showing a measurement image displayed on an LCD panel in a speed measurement mode.
[Explanation of symbols]
10 system control circuit
12 Main switch (SW_M)
14 shooting optical system
16 zoom drive mechanism
18 Tele side switch (SW_T)
20 wide side switch (SW_W)
22 zoom encoder
24 ° focusing lens drive mechanism
26 record / playback switch (R / P SW)
28 ° photometric switch (SW_P)
30mm release switch (SW_R)
32mm CCD image sensor
34 ° optical low pass filter (LPF)
36 CCD drive circuit
38 correlated double sampling circuit (CDS)
40 amplifier (AMP)
42 analog / digital (A / D) converter
44 Video Ram (VRAM)
46 digital / analog (D / A) converter
48 video encoder
50mm liquid crystal display (LCD) panel
52 dynamic ram (DRAM)
54 CF card driver
56 interface (I / F) circuit
58 Menu display switch (SW_MD)
60 menu selection switch (SW_S)
62 Menu confirmation switch (SW_K)

Claims (7)

The subject image formed on the light receiving surface of the solid-state image sensor at a predetermined photographing magnification by the photographing optical system is photoelectrically converted for a predetermined charge accumulation time and read as one frame of pixel signal. A digital camera that generates a captured image based on the
A digital camera comprising a speed measurement function for measuring the speed of the moving subject based on the shooting magnification and the charge accumulation time when the shot image is shot as a measurement image including the moving subject. The digital camera according to claim 1, wherein the speed measurement function is:
Extraction means for extracting an image blur area of the moving subject included in the measurement image from the measurement image,
Calculating means for calculating the width and the height of the image blur area;
A digital camera, comprising: calculation means for calculating the speed of the moving subject based on the width and height of the image blur area detected by the calculation means, the imaging magnification, and the charge accumulation time. The digital camera according to claim 2, wherein the extraction unit is a background image corresponding to an image obtained by removing the moving subject from the measurement image, and is a separately captured image at the imaging magnification and the charge accumulation time, and the measurement image is used as the measurement image. A digital camera that extracts an image blur area of the moving subject from the measurement image by performing differential processing on the moving image. 4. The digital camera according to claim 3, wherein the extraction unit detects a relative angular displacement and a relative translation between the background image and the measurement image so as to spatially match one of the background image and the measurement image with the other. A digital camera, comprising: 5. The digital camera according to claim 1, wherein the photographing optical system is configured as a zoom optical system, a focal length detecting unit that detects a focal length of the zoom optical system, and the photographing optical system. 6. And a focusing optical system position detecting means for detecting a position of the focusing optical system in the optical axis direction. 6. The digital camera according to claim 1, further comprising a monitor for displaying the measured image, wherein the speed of the moving subject calculated by the calculator is displayed on the monitor. A digital camera characterized by being superimposed on a measurement image. 6. The digital camera according to claim 1, further comprising: a speed measurement mode selection unit for selectively selecting a speed measurement mode; and a measurement image when the speed measurement mode is selected by the speed measurement mode selection unit. And a control unit for automatically executing the speed measurement processing when one or more background images are captured.

Images