JP2004328053A

JP2004328053A - Flaw detecting method of wide dynamic range solid-state image pickup device, pixel defect inspection device, and digital camera

Info

Publication number: JP2004328053A
Application number: JP2003115828A
Authority: JP
Inventors: Hirokazu Kobayashi; 寛和小林; Kazuya Oda; 和也小田
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 2003-04-21
Filing date: 2003-04-21
Publication date: 2004-11-18

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flaw detecting method capable of determining flaws on a master photosensitive section and a slave photosensitive section arranged on each pixel in a wide dynamic range solid-state image pickup device, and to provide a pixel defect detecting device and a digital camera. <P>SOLUTION: The pixel defect inspection device 10 compares master photosensitive section data with a predetermined threshold (S106) to perform either of determinations that the master photosensitive section has flaws (S108) or that it has no flaw (S110). In the case of the determination that the master photosensitive section has no flaw, the device 10 compares slave photosensitive section data with the master photosensitive section data using a sensitivity ratio of the master and slave photosensitive sections (S112) to perform either of determinations that the slave photosensitive section has flaws (S114) or that it has no flaw (S116). In the case of that the slave photosensitive section has flaws, the device 10 records the address of the flaw of the master photosensitive section which is determined that it has flaws (S115), determines that the slave photosensitive section has flaws (S116), and can record the address of flaw of the slave photosensitive section which is determined that it has flaws (S118). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、各画素に感度の異なる感光部を配置して広ダイナミックレンジで画像情報を得る固体撮像素子のキズ検出方法および画素欠陥検査装置ならびにこのキズ検出方法を適用したディジタルカメラに関するものである。
【０００２】
【従来の技術】
たとえば、電子スチルカメラまたはビデオカメラなどの撮像装置には、数十万ないし数百万個の感光部が形成される固体撮像素子が用いられている。このような固体撮像素子には、その製造工程等に起因して、入射光に反応しない感光部や、入射光がなくても異常に多い暗電流を発生する感光部が含まれていることがある。この欠陥のある感光部を有する欠陥画素は、たとえば、液晶表示などに動画表示する際にいわゆる黒キズや白キズなどとして現われる。
【０００３】
そこで、従来から、固体撮像素子の欠陥画素を検査するために、固体撮像素子における感光部のキズを検出する方法および装置が知られている。特許文献１に記載の固体撮像素子の黒欠陥検出装置では、感度差のある光フィルタを用いた固体撮像素子について正確な黒欠陥検出を実現している。この黒欠陥検出において、感度差を有する複数種のフィルタについてあらかじめ決められた利得係数をそれぞれ設定し、各光フィルタに対応する受光素子の出力信号レベルに対してこの利得係数を乗じることにより、それぞれの光フィルタの感度特性がそろうようにレベル補正を行い、黒欠陥の発生している画素について欠陥レベルおよびその位置を検出することができる。
【０００４】
【特許文献１】
特願２００２−２９０８３７。
【０００５】
【発明が解決しようとする課題】
ところで、固体撮像素子には、入射光に対する感度が高い主感光部、および入射光に対する感度が低い従感光部を各画素に配置して広ダイナミックレンジで撮像するものがある。たとえば、図４に示すように、主感光部は、飽和レベルが高く、多くの信号電荷を測定することができるが、被写界が明るいと飽和しやすく、高い入射光量を測定できない。一方、従感光部は、飽和しにくく、高い入射光量を測定することができるが、その飽和レベルは主感光部よりも低い。
【０００６】
しかし、特許文献１に記載の黒欠陥検出装置は、上記のような広ダイナミックレンジ固体撮像素子において、各画素における主感光部および従感光部のそれぞれのキズを検出することができない。
【０００７】
したがって、このような従感光部における明時欠陥を判定するとき、主感光部が飽和する入射光量付近において従感光部データを取得し、これを主感光部キズ判定と同様に閾値比較を行って従感光部キズ判定を行う方法がある。しかし、この方法は、主感光部キズの判定には適しているが、従感光部データの出力値はかなり小さく、またＳ／Ｎが低いため、正確なキズ判定を行うことができない。また、主感光部が飽和する入射光量よりもさらに大きな光量で従感光部のデータを取得し、主感光部キズ判定と同様に閾値比較を行って高いＳ／Ｎで従感光部キズ判定を行う方法があるが、主感光部キズ判定と合わせ２回分の光量調節およびデータ取り込みを要するため作業効率が悪化する。
【０００８】
本発明はこのような従来技術の欠点を解消し、広ダイナミックレンジ固体撮像素子において、各画素に配置された主感光部および従感光部のキズを判定することができるキズ検出方法および画素欠陥検査装置ならびにディジタルカメラを提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明によれば、入射光を光電変換する第１の感光部と、第１の感光部より低い感度で入射光を光電変換する第２の感光部とを配して各画素を形成する固体撮像素子を用いて、第１の感光部および第２の感光部の欠陥を検査する画素欠陥検査装置は、この固体撮像素子を露光して、第１の感光部および第２の感光部から、それぞれ第１の画像信号および第２の画像信号を得る露光手段と、第１の画像信号を第１の閾値を用いて比較して、第１の感光部にキズがあるか否かを判定する第１の判定手段と、第２の画像信号を第１の感光部と第２の感光部との感度比を用いて比較して、第２の感光部にキズがあるか否かを判定する第２の判定手段とを含み、第１の判定手段の結果が、キズなし判定のときには、第２の判定手段で第２の感光部のキズの有無を判定し、キズあり判定のときには、第２の感光部にキズがあると判定することを特徴とする。
【００１０】
【発明の実施の形態】
次に添付図面を参照して本発明による広ダイナミックレンジ固体撮像素子のキズ検出方法を適用した画素欠陥検査装置の実施例を詳細に説明する。
【００１１】
第１の実施例として、画素欠陥検査装置１０は、図１に示すように、主感光部データを所定の閾値と比較して（ステップＳ１０６）、主感光部キズなし判定（ステップＳ１０８）および主感光部キズあり判定（ステップＳ１１０）のいずれかを判定し、主感光部キズなし判定の場合には、さらに同じ画素位置の従感光部データを主感光部と従感光部との感度比を用いて主感光部データと比較して（ステップＳ１１２）、従感光部キズなし判定（ステップＳ１１４）および従感光部キズあり判定（ステップＳ１１６）のいずれかを判定し、主感光部キズあり判定の場合には、キズありと判定された主感光部のキズアドレスを記録し（ステップＳ１１５）、従感光部キズあり判定（Ｓ１１６）を判定して、キズありと判定された従感光部のキズアドレスを記録する（ステップＳ１１８）。
【００１２】
実施例の画素欠陥検査装置１０には、図２に示すように、被写界からの入射光を光学レンズ系１２において取り込み、システム制御部１４およびタイミングパルス発生器１６で各部を制御して、この被写界像を固体撮像素子１８で撮像するもので、撮像した画像を信号処理部２０で信号処理して、メモリ２２で記憶し、キズ検出の条件や結果などの情報を記録部２４で記録する装置である。なお、本発明の理解に直接関係のない部分は、図示を省略し、冗長な説明を避ける。
【００１３】
光学レンズ系１２には、具体的な構成を図示しないが、レンズ、絞り調整機構、シャッタ機構、ズーム機構および自動焦点調節機構などが含まれて、所望の被写界像を取り込んで固体撮像素子１８の撮像面に入射する光入射機構である。なお、以下の説明において、各信号はその現れる接続線の参照番号で特定する。
【００１４】
システム制御部１４は、本装置全体の動作を制御、統括する制御機能部である。本実施例において、システム制御部１４は、図示しないが、たとえば中央演算処理装置（ＣｅｎｔｒａｌＰｒｏｃｅｓｓｉｎｇＵｎｉｔ：ＣＰＵ）を含んでいる。
【００１５】
本実施例におけるシステム制御部１４は、露光の開始や信号電荷の読み出しを指示する制御信号２０４をタイミング発生器１６に供給して露光を制御する。また、制御信号２１２によりメモリ２２を制御して、メモリ２２に記憶された主感光部データおよび従感光部データを読み出す。システム制御部１４は、主感光部データおよび従感光部データを、たとえば画素ごとに検査して、主感光部および従感光部におけるキズの有無を検出する。また、キズが検出された主感光部および従感光部のキズアドレス、つまり画素位置を、制御信号２１４により記録部２４に記録する。このとき、主感光部と従感光部とを区別してキズアドレスを記録し、このキズが主感光部および従感光部の両方に検出された場合には、両方に記録する。
【００１６】
また、システム制御部１４は、平面光を入射した場合の主感光部データおよび従感光部データから、主感光部と従感光部との感度比をあらかじめ測定しておくことができる。このとき、画面中心部あるいは画面全体にわたって、画素ごとに感度比を測定してもよく、また、デバイス生産上、感度比の制御性が高い場合、感度比として代表する設計値を用いてもよい。
【００１７】
タイミングパルス発生器１６は、本装置１０を動作させる基本クロック（システムクロック）を発生する発信機を有して、たとえば、図示しないが、基本クロックをほとんど全てのブロックに供給すると共に、この基本クロックを分周して様々なタイミング信号も生成する。本実施例では特に、タイミングパルス発生器１６は、システム制御部１４から供給される制御信号２０４に基づいて固体撮像素子１８を制御する制御信号２０６を供給する。
【００１８】
固体撮像素子１８は、具体的な構成は図示しないが、撮影画像の１画面を形成する撮像面を含み、この撮像面は、複数の各画素に対応する受光部を備えている。固体撮像素子１８は、その撮像面に結像される被写界像を電気信号２０８に光電変換する機能を有し、たとえば、電荷結合素子（ＣｈａｒｇｅＣｏｕｐｌｅｄＤｅｖｉｃｅ：ＣＣＤ）や金属酸化膜型半導体（ＭｅｔａｌＯｘｉｄｅＳｅｍｉｃｏｎｄｕｃｔｏｒ：ＭＯＳ）等のいずれのイメージセンサでもよい。
【００１９】
この撮像面において、複数の受光部は、行方向および列方向に１つおきに位置をずらして配列する、ハニカム配列を用いるとよく、また、行方向および列方向に１つおきに位置をずらして配列してもよい。本実施例では、これらの受光部のそれぞれが、高感度の受光素子である主感光部、および低感度の受光素子である従感光部を備えている。主感光部および従感光部は、入射光を受光した際に、光を受光光量に応じた信号電荷に光電変換する光センサであり、たとえば、フォトダイオードが用いられる。本実施例では、図４に示すように、主感光部は、主感光部飽和レベルで飽和する。一方、従感光部は、主感光部飽和レベルより低い従感光部飽和レベルで飽和するが、入射光量が多い、たとえばハイライト領域に達しても飽和しにくい。
【００２０】
本実施例の固体撮像素子１８は、制御信号２０６に制御されて、各感光部で光電変換によって得た信号電荷を読み出し、この信号電荷を出力回路（図示せず）においてアナログ画像信号２０８に変換して信号処理部２０に出力する。
【００２１】
信号処理部２０は、アナログ画像信号に信号処理を施してディジタル画像信号に変換する機能を有し、本実施例ではアナログ・ディジタル（Ａ／Ｄ）変換器を含んでアナログ画像信号の信号レベルを所定の量子化レベルにより量子化してディジタル画像信号に変換する。
【００２２】
メモリ２２は、ディジタル画像信号を書き換え可能に保存する機能を有する。本実施例では、保存するディジタル画像信号には主感光部データおよび従感光部データが含まれる。
【００２３】
記録部２４は、キズ検出の条件や結果などの情報２１４を記録する機能を有する。本実施例では、記録部２４は、インターフェース（Ｉ／Ｆ）２６を介して検出情報２１６を情報記録媒体２８で記録する。情報記録媒体２８は、書き込み可能なＲＯＭ（ＲｅａｄＯｎｌｙＭｅｍｏｒｙ）でよいが、半導体メモリが搭載されたメモリカードや光磁気ディスク等の回転記録体を収容したパッケージなどを用いて、着脱可能としてもよい。
【００２４】
本実施例では、情報記録媒体２８は、たとえば、図３に示すように、感度比データなどのキズ検出に要した条件を記録するセクション３０２と、キズアドレスなどのキズ検出の結果を記録するセクション３０４を有する。たとえば、セクション３０２は、感度比をＲ，Ｇ，Ｂで表わして、それぞれ上から記録する。また、セクション３０２は、主感光部データや従感光部データの比較に用いた閾値などを記録してもよい。一方、セクション３０４におけるキズアドレスは、たとえば、キズが検出された画素位置の横方向および縦方向の座標を、キズが検出された順に上から記録する。また、セクション３０４は、主感光部と従感光部とのキズアドレスを分別して記録するとよい。
【００２５】
次に画素欠陥検査装置１０の動作を、図１のフローチャートを参照しながら説明する。操作者は本装置を操作して、まず被写界からの入射光を露光する（Ｓ１０２）。このとき、本装置１０では、入射光が光学レンズ系１２を介して、固体撮像素子１８の撮像面に入射する。
【００２６】
一方、システム制御部１４では、露光開始を指示する制御信号２０４がタイミングパルス発生部１６に供給され、タイミングパルス発生部１６では、制御信号２０６が固体撮像素子１８を制御して、たとえば電子シャッタが駆動して露光を開始させる。さらに、信号電荷読み出しを指示する制御信号２０４がタイミングパルス発生部１６に供給され、タイミングパルス発生部１６では、制御信号２０６が固体撮像素子１８を制御して各感光部の信号電荷を読み出させる。本実施例では特に、露光時に主感光部出力がｋ［ｍＶ］となるように制御する。
【００２７】
固体撮像素子１８において、各感光部から読み出された信号電荷は、アナログ画像信号２０８として信号処理部２０に供給される。アナログ画像信号２０８は、信号処理部２０において、アナログ・ディジタル変換などの信号処理が施されてディジタル画像信号２１０に変換される。さらに、ディジタル画像信号２１０は、メモリ２２に保存される（Ｓ１０４）。
【００２８】
次に、システム制御部１４において、メモリ２２に保存されたディジタル画像信号２１０に含まれる主感光部データＭａｉｎ（ｙ，ｘ）および従感光部データＳｕｂ（ｙ，ｘ）に基づいて、主感光部および従感光部のキズを画素ごとに検査する。これらｙおよびｘは、それぞれ画素位置の縦方向および横方向の座標を示す。
【００２９】
まず、主感光部データを所定の閾値と比較する（Ｓ１０６）。たとえば、上述の出力値ｋを用いて、Ｍａｉｎ（ｙ，ｘ）／ｋ＜０．１が正の場合、主感光部はキズなし（Ｓ１０８）と判定し、負の場合、主感光部はキズあり（Ｓ１１０）と判定する。
【００３０】
主感光部キズなし（Ｓ１０８）の場合、従感光部データをその感度比ｊを用いて主感光部データと比較する（Ｓ１１２）。たとえば、閾値εを用いて、｜Ｓｕｂ（ｙ，ｘ）×ｊ−Ｍａｉｎ（ｙ，ｘ）｜＜εが正の場合、従感光部はキズなし（Ｓ１１４）と判定し、負の場合、従感光部はキズあり（Ｓ１１６）と判定する。
【００３１】
一方、主感光部キズあり（Ｓ１１０）の場合、その主感光部の画素位置が記録部２４に記録され（Ｓ１１５）、さらに、従感光部データにかかわらず、従感光部はキズあり（Ｓ１１６）と判定される。
【００３２】
さらに、従感光部キズあり（Ｓ１１６）である場合、主感光部のキズの有無にかかわらず、その従感光部の画素位置を記録部に記録する（Ｓ１１８）。
【００３３】
上記の主感光部および従感光部のキズの検査がされていない画素がある場合、ステップＳ１２０において、ステップＳ１０６に戻る。また、全画素に対して検査が終了した場合、終了する。
【００３４】
また、本発明では、露光（Ｓ１０２）において、主感光部および従感光部を異なる露光時間で露光してもよい。たとえば、図５に示すように、電子シャッタ（ａ）の駆動が開始してから、１回目のタイミングパルスに応じて主感光部データ読出しパルスが立ち上がり、２回目のタイミングパルスに応じて従感光部データ読出しパルスが立ち上がる。これによって、従感光部は、その露光時間が長いために、より微弱な光を検出することができる。
【００３５】
第２の実施例として、画素欠陥検査装置１０において、システム制御部１４は、主感光部キズありと判定した場合に、さらに従感光部データを所定の閾値と比較することによって、従感光部のキズの有無を判定してもよい。たとえば、図６に示すように、主感光部キズあり判定（Ｓ１１０）であった場合、この主感光部のキズアドレスを記録部２４に記録する（ステップＳ１１５）。次に、従感光部データを所定の閾値と比較する（ステップＳ６０４）。たとえば、上述の出力値ｋおよび感度比ｊを用いて、Ｓｕｂ（ｙ，ｘ）／ｋ／ｊ＜０．５が正の場合、従感光部はキズなし（ステップＳ６０６）と判定し、負の場合、従感光部はキズあり（ステップＳ６０８）と判定する。従感光部キズあり判定（Ｓ６０８）であった場合に限り、この従感光部のキズアドレスを記録部２４に記録する（ステップＳ６１０）。
【００３６】
第３の実施例として、画素欠陥検査装置１０において、システム制御部１４は、主感光部キズなしと判定した場合に、従感光部データをその感度比を用いて比較し、さらに所定の閾値と比較して従感光部のキズの有無を判定してもよい。たとえば、図７に示すように、主感光部キズなし判定（Ｓ１０８）であった場合、従感光部をその感度比ｊを用いて主感光部データと比較して評価値Ａを算出する（ステップＳ７０２）。たとえば評価値Ａは、｜Ｓｕｂ（ｙ，ｘ）×ｊ−Ｍａｉｎ（ｙ，ｘ）｜で算出される。次に、従感光部データを所定の閾値と比較して評価値Ｂを算出する（ステップＳ７０４）。たとえば評価値Ｂは、Ｓｕｂ（ｙ，ｘ）／ｋ／ｊで算出される。次に、ステップ（ステップＳ７０６）において、所定の比較値αおよびβと、閾値δとを用いて、αＡ＋βＢ＜δが正の場合、従感光部はキズなし（Ｓ１１４）と判定し、負の場合、従感光部はキズあり（ステップＳ７０８）と判定する。
【００３７】
また、他の実施例として、本発明のキズ検出方法は、ディジタルカメラに適用することができる。たとえば、ディジタルカメラは、図８に示すように、システム制御部５０からの制御信号８０２に制御されて、Ａ／Ｄ変換器５２から供給されるディジタル画像信号８０４に対して、信号処理部５４でディジタル信号処理するもので、このディジタル信号処理を施したディジタル画像信号８０６および８０８を、それぞれ記録部５６および表示部５８に供給する。
【００３８】
本実施例では、ディジタル画像信号８０４には主感光部データおよび従感光部データが含まれ、信号処理部５４は、画像メモリ６０および８０を有して、主感光部データおよび従感光部データをそれぞれ主画像信号および従画像信号として一時蓄積する。また、信号処理部５４は、主画像信号を処理するホワイトバランス（ＷＢ）ゲイン部６２およびガンマ（γ）変換部６４、ならびに従画像信号を処理するＷＢゲイン部８２およびγ変換部８４を有する。さらに、主画像信号と従画像信号とを合成する画像加算部６６を有し、また、同時化処理部６８、各種補正部７０、ＪＰＥＧ（ＪｏｉｎｔＰｈｏｔｏｇｒａｐｈｉｃＥｘｐｅｒｔｓＧｒｏｕｐ）圧縮部７２および画像縮小部７４において、合成後の主画像信号を処理する。
【００３９】
本実施例では特に、システム制御部５０は、制御信号８０２により信号処理部５４を制御して、画像メモリ６０および８０から、それぞれ、たとえば露光時の主感光部データおよび従感光部データを読み出す。さらに、上述のような実施例、すなわち図１、図６または図７に示すようなフローを実行して、読み込んだ主感光部データおよび従感光部データから主感光部および従感光部のキズを検出する。
【００４０】
ここで、主感光部のキズアドレスを示す主感光部キズ補正データ、および従感光部のキズアドレスを示す従感光部キズ補正データを作成し、これらをシステム制御部５０におけるＲＯＭ９２に格納する。システム制御部５０は、これらのキズ補正データに基づいて、撮影時の主感光部データおよび従感光部データをキズ補正することができる。
【００４１】
これらのキズ補正データは、露光時に毎回作成しなくてもよく、たとえば、電源を入れて最初の露光時にのみ作成してもよい。また、キズ補正データの作成において用いられる主感光部データおよび従感光部データは、露光時のデータに限らず、撮影時のデータを用いてもよい。また、各種補正部７０において、これらのキズ補正データを用いて、合成後の主画像信号を補正してもよい。
【００４２】
【発明の効果】
このように本発明のキズ検出方法によれば、主感光部データを所定の閾値と比較した後で、従感光部データをその感度比と比較することにより、広ダイナミックレンジ固体撮像素子に対して、主感光部および従感光部のそれぞれにキズがあるかを検出することができ、この固体撮像素子の出荷における検査に効果的に適用することができる。
【００４３】
また、本発明は、従感光部における入射光量を高くしてキズ判定し、光量調節およびデータ取り込みを２回分行うことなく、高いＳ／Ｎでキズ判定を行うことができる。
【００４４】
また、本発明のキズ検出方法をディジタルカメラなどに適用すると、各画素の主感光部および従感光部のそれぞれに欠陥を検出することができるため、主感光部データおよび従感光部データのそれぞれに適した補正をすることができる。
【図面の簡単な説明】
【図１】本発明のキズ検出方法を適用した画素欠陥検査装置の動作手順を説明するフローチャートである。
【図２】本発明に係るキズ検出方法を適用した画素欠陥検査装置の一実施例を示すブロック図である。
【図３】図２に示す実施例の画素欠陥検査装置が有するメモリが格納するキズ検出の条件および結果を例示した図である。
【図４】図２に示す実施例の画素欠陥検査装置が有する固体撮像素子において、入射光量と、主感光部および従感光部における信号電荷量との関係を示す図である。
【図５】図２に示す実施例の画素欠陥検査装置において、従感光部の露光時間を主感光部より長くする際の、システム制御部およびタイミングパルス発生部におけるタイミングチャートである。
【図６】本発明に係るキズ検出方法を適用した画素欠陥検査装置において、第２の実施例のキズ検出方法の動作手順を説明するフローチャートである。
【図７】本発明に係るキズ検出方法を適用した画素欠陥検査装置において、第３の実施例のキズ検出方法の動作手順を説明するフローチャートである。
【図８】本発明に係るキズ検出方法を適用したディジタルカメラが有する信号処理部について詳細に示すブロック図である。
【符号の説明】
１０画素欠陥検査装置
１２光学レンズ系
１４システム制御部
１６タイミングパルス発生部
１８固体撮像素子
２０信号処理部
２２メモリ
２４記録部
２６インターフェース
２８情報記録媒体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flaw detection method and a pixel defect inspection apparatus for a solid-state imaging device that obtains image information in a wide dynamic range by arranging photosensitive portions having different sensitivities for each pixel, and a digital camera to which this flaw detection method is applied. .
[0002]
[Prior art]
For example, an imaging apparatus such as an electronic still camera or a video camera uses a solid-state imaging device on which hundreds of thousands to millions of photosensitive parts are formed. Such a solid-state imaging device may include a photosensitive part that does not react to incident light due to its manufacturing process or the like, or a photosensitive part that generates an abnormally large dark current without incident light. is there. The defective pixel having the defective photosensitive portion appears as a so-called black defect or white defect when displaying a moving image on a liquid crystal display, for example.
[0003]
In order to inspect defective pixels of a solid-state image sensor, a method and an apparatus for detecting a scratch on a photosensitive part in the solid-state image sensor are conventionally known. In the black defect detection device for a solid-state image sensor described in Patent Document 1, accurate black defect detection is realized for a solid-state image sensor using an optical filter having a sensitivity difference. In this black defect detection, a predetermined gain coefficient is set for each of a plurality of types of filters having sensitivity differences, and the output signal level of the light receiving element corresponding to each optical filter is multiplied by this gain coefficient, respectively. The level correction is performed so that the sensitivity characteristics of the optical filters are aligned, and the defect level and its position can be detected for the pixel in which the black defect occurs.
[0004]
[Patent Document 1]
Japanese Patent Application No. 2002-290837.
[0005]
[Problems to be solved by the invention]
By the way, there are solid-state imaging devices in which a main photosensitive portion having high sensitivity to incident light and a secondary photosensitive portion having low sensitivity to incident light are arranged in each pixel and imaged in a wide dynamic range. For example, as shown in FIG. 4, the main photosensitive portion has a high saturation level and can measure a large amount of signal charges. However, when the object field is bright, it is easily saturated and cannot measure a high amount of incident light. On the other hand, the secondary photosensitive portion is less likely to be saturated and can measure a high amount of incident light, but its saturation level is lower than that of the main photosensitive portion.
[0006]
However, the black defect detection device described in Patent Document 1 cannot detect the scratches of the main photosensitive portion and the secondary photosensitive portion in each pixel in the wide dynamic range solid-state imaging device as described above.
[0007]
Therefore, when determining such a light-time defect in the secondary photosensitive portion, secondary photosensitive portion data is acquired in the vicinity of the incident light amount at which the primary photosensitive portion is saturated, and this is compared with the threshold in the same manner as the primary photosensitive portion scratch determination. There is a method for determining whether the secondary photosensitive portion is scratched. However, this method is suitable for determining the scratch on the main photosensitive portion, but the output value of the secondary photosensitive portion data is considerably small and the S / N is low, so that accurate scratch determination cannot be performed. Further, the data of the secondary photosensitive portion is acquired with a light amount greater than the amount of incident light that saturates the primary photosensitive portion, the threshold comparison is performed in the same manner as the primary photosensitive portion scratch determination, and the secondary photosensitive portion scratch determination is performed with a high S / N. Although there is a method, work efficiency is deteriorated because it is necessary to adjust the amount of light and fetch data for two times together with determination of scratches on the main photosensitive portion.
[0008]
The present invention eliminates the disadvantages of the prior art, and in a wide dynamic range solid-state imaging device, a flaw detection method and a pixel defect inspection capable of determining flaws in a main photosensitive portion and a sub-photosensitive portion arranged in each pixel. An object is to provide an apparatus and a digital camera.
[0009]
[Means for Solving the Problems]
According to the present invention, the first photosensitive part that photoelectrically converts incident light and the second photosensitive part that photoelectrically converts incident light with lower sensitivity than the first photosensitive part are arranged to form each pixel. A pixel defect inspection apparatus that inspects defects in the first photosensitive portion and the second photosensitive portion using the imaging element exposes the solid-state imaging element, and from the first photosensitive portion and the second photosensitive portion, The exposure means for obtaining the first image signal and the second image signal, respectively, is compared with the first image signal using the first threshold value, and it is determined whether or not the first photosensitive portion is damaged. The first determination means and the second image signal are compared using the sensitivity ratio between the first photosensitive portion and the second photosensitive portion to determine whether the second photosensitive portion is flawed. And when the result of the first determination means is no scratch determination, the second determination means causes the second photosensitive portion to be scratched. It determines the presence, when the scratches determination, and judging that there is a flaw in the second photosensitive section.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a pixel defect inspection apparatus to which a scratch detection method for a wide dynamic range solid-state imaging device according to the present invention is applied will be described in detail with reference to the accompanying drawings.
[0011]
As a first example, as shown in FIG. 1, the pixel defect inspection apparatus 10 compares the main photosensitive portion data with a predetermined threshold (step S106), determines whether there is no main photosensitive portion flaw (step S108), and If any of the photosensitive part scratch determination (step S110) is determined and there is no main photosensitive part scratch determination, the secondary photosensitive part data at the same pixel position is further used as the sensitivity ratio between the primary photosensitive part and the secondary photosensitive part. In comparison with the main photosensitive portion data (step S112), it is determined whether there is any secondary photosensitive portion scratch determination (step S114) or secondary photosensitive portion scratch determination (step S116). Is recorded with the scratch address of the primary photosensitive portion determined to be scratched (step S115), the secondary photosensitive portion scratch determination is determined (S116), and the secondary photosensitive portion determined to be scratched is scratched. Les record (step S118).
[0012]
In the pixel defect inspection apparatus 10 of the embodiment, as shown in FIG. 2, the incident light from the object scene is taken in the optical lens system 12, and each part is controlled by the system control unit 14 and the timing pulse generator 16, The object scene image is picked up by the solid-state image sensor 18. The picked-up image is signal-processed by the signal processing unit 20 and stored in the memory 22, and information such as a flaw detection condition and result is recorded in the recording unit 24. It is a recording device. Note that portions not directly related to understanding the present invention are not shown and redundant description is avoided.
[0013]
The optical lens system 12 includes a lens, an aperture adjustment mechanism, a shutter mechanism, a zoom mechanism, an automatic focus adjustment mechanism, and the like, although a specific configuration is not shown in the figure, and captures a desired object scene image to obtain a solid-state imaging device. This is a light incident mechanism that is incident on the image pickup surface 18. In the following description, each signal is specified by the reference number of the connecting line in which it appears.
[0014]
The system control unit 14 is a control function unit that controls and controls the overall operation of the apparatus. In the present embodiment, the system control unit 14 includes, for example, a central processing unit (CPU), although not shown.
[0015]
The system control unit 14 in this embodiment controls the exposure by supplying a control signal 204 for instructing the start of exposure or reading of signal charges to the timing generator 16. Further, the memory 22 is controlled by the control signal 212 to read out the main photosensitive portion data and the secondary photosensitive portion data stored in the memory 22. The system control unit 14 inspects the main photosensitive portion data and the secondary photosensitive portion data for each pixel, for example, and detects the presence or absence of scratches in the primary photosensitive portion and the secondary photosensitive portion. Further, the flaw addresses of the main photosensitive portion and the sub-photosensitive portion where the flaw is detected, that is, the pixel positions are recorded in the recording portion 24 by the control signal 214. At this time, a flaw address is recorded by distinguishing between the main photosensitive portion and the sub-photosensitive portion, and when this flaw is detected in both the main photosensitive portion and the sub-photosensitive portion, it is recorded in both.
[0016]
Further, the system control unit 14 can measure in advance the sensitivity ratio between the main photosensitive unit and the secondary photosensitive unit from the primary photosensitive unit data and the secondary photosensitive unit data when plane light is incident. At this time, the sensitivity ratio may be measured for each pixel over the center of the screen or the entire screen, and if the controllability of the sensitivity ratio is high in device production, a design value representative of the sensitivity ratio may be used. .
[0017]
The timing pulse generator 16 includes a transmitter that generates a basic clock (system clock) for operating the apparatus 10. For example, although not shown, the timing pulse generator 16 supplies the basic clock to almost all the blocks. To generate various timing signals. Particularly in the present embodiment, the timing pulse generator 16 supplies a control signal 206 for controlling the solid-state imaging device 18 based on the control signal 204 supplied from the system control unit 14.
[0018]
Although a specific configuration is not illustrated, the solid-state imaging device 18 includes an imaging surface that forms one screen of a captured image, and the imaging surface includes a light receiving unit corresponding to each of a plurality of pixels. The solid-state imaging device 18 has a function of photoelectrically converting an object scene image formed on the imaging surface into an electric signal 208. For example, a charge coupled device (CCD) or a metal oxide semiconductor ( Any image sensor such as Metal Oxide Semiconductor (MOS) may be used.
[0019]
In this imaging surface, it is preferable to use a honeycomb arrangement in which the plurality of light receiving portions are arranged with the positions shifted every other in the row direction and the column direction, and every other position is shifted in the row direction and the column direction. May be arranged. In this embodiment, each of these light receiving portions includes a main photosensitive portion that is a highly sensitive light receiving element and a secondary photosensitive portion that is a low sensitive light receiving element. The main photosensitive portion and the secondary photosensitive portion are optical sensors that photoelectrically convert light into signal charges corresponding to the amount of received light when receiving incident light, and a photodiode is used, for example. In the present embodiment, as shown in FIG. 4, the main photosensitive portion is saturated at the main photosensitive portion saturation level. On the other hand, the secondary photosensitive portion is saturated at the secondary photosensitive portion saturation level lower than the primary photosensitive portion saturation level. However, the secondary photosensitive portion is not easily saturated even when the amount of incident light is large, for example, reaches a highlight region.
[0020]
The solid-state imaging device 18 of this embodiment is controlled by a control signal 206 to read out signal charges obtained by photoelectric conversion in each photosensitive portion, and convert the signal charges into an analog image signal 208 in an output circuit (not shown). And output to the signal processing unit 20.
[0021]
The signal processing unit 20 has a function of performing signal processing on the analog image signal to convert it into a digital image signal. In this embodiment, the signal processing unit 20 includes an analog / digital (A / D) converter to adjust the signal level of the analog image signal. Quantization is performed at a predetermined quantization level and converted into a digital image signal.
[0022]
The memory 22 has a function of storing a digital image signal in a rewritable manner. In this embodiment, the stored digital image signal includes main photosensitive portion data and secondary photosensitive portion data.
[0023]
The recording unit 24 has a function of recording information 214 such as scratch detection conditions and results. In the present embodiment, the recording unit 24 records the detection information 216 on the information recording medium 28 via the interface (I / F) 26. The information recording medium 28 may be a writable ROM (Read Only Memory), but may be detachable using a package containing a rotating recording body such as a memory card on which a semiconductor memory is mounted or a magneto-optical disk. .
[0024]
In the present embodiment, for example, as shown in FIG. 3, the information recording medium 28 has a section 302 for recording conditions required for detecting defects such as sensitivity ratio data, and a section for recording the results of detecting defects such as flaw addresses. 304. For example, in section 302, sensitivity ratios are represented by R, G, and B, and recorded from above. In addition, the section 302 may record a threshold value used for comparison of the main photosensitive portion data and the secondary photosensitive portion data. On the other hand, the scratch address in the section 304 records, for example, the horizontal and vertical coordinates of the pixel position where the scratch was detected from the top in the order in which the scratch was detected. Further, the section 304 may separately record the flaw addresses of the main photosensitive portion and the secondary photosensitive portion.
[0025]
Next, the operation of the pixel defect inspection apparatus 10 will be described with reference to the flowchart of FIG. The operator operates this apparatus to first expose incident light from the object scene (S102). At this time, in the present apparatus 10, incident light is incident on the imaging surface of the solid-state imaging device 18 via the optical lens system 12.
[0026]
On the other hand, in the system control unit 14, a control signal 204 instructing the start of exposure is supplied to the timing pulse generation unit 16, and in the timing pulse generation unit 16, the control signal 206 controls the solid-state imaging device 18, for example, an electronic shutter Drive to start exposure. Further, a control signal 204 for instructing signal charge readout is supplied to the timing pulse generator 16, and in the timing pulse generator 16, the control signal 206 controls the solid-state imaging device 18 to read out the signal charges of each photosensitive unit. . In this embodiment, in particular, control is performed so that the main photosensitive portion output becomes k [mV] during exposure.
[0027]
In the solid-state imaging device 18, the signal charge read from each photosensitive unit is supplied to the signal processing unit 20 as an analog image signal 208. The analog image signal 208 is subjected to signal processing such as analog / digital conversion in the signal processing unit 20 and converted into a digital image signal 210. Further, the digital image signal 210 is stored in the memory 22 (S104).
[0028]
Next, in the system control unit 14, based on the main photosensitive unit data Main (y, x) and the secondary photosensitive unit data Sub (y, x) included in the digital image signal 210 stored in the memory 22, the main photosensitive unit. In addition, the sub photosensitive portion is inspected for each pixel. These y and x indicate the vertical and horizontal coordinates of the pixel position, respectively.
[0029]
First, the main photosensitive portion data is compared with a predetermined threshold (S106). For example, when Main (y, x) / k <0.1 is positive using the output value k described above, the main photosensitive portion is determined not to be scratched (S108), and when negative, the main photosensitive portion is scratched. It is determined that there is (S110).
[0030]
In the case where there is no scratch on the main photosensitive portion (S108), the slave photosensitive portion data is compared with the main photosensitive portion data using the sensitivity ratio j (S112). For example, using the threshold value ε, if | Sub (y, x) × j−Main (y, x) | <ε is positive, it is determined that the secondary photosensitive portion is not scratched (S114). The photosensitive part is determined to be scratched (S116).
[0031]
On the other hand, in the case where there is a scratch on the main photosensitive portion (S110), the pixel position of the main photosensitive portion is recorded in the recording unit 24 (S115), and the secondary photosensitive portion is scratched regardless of the secondary photosensitive portion data (S116). It is determined.
[0032]
Further, if there is a scratch on the secondary photosensitive portion (S116), the pixel position of the secondary photosensitive portion is recorded on the recording portion regardless of whether the primary photosensitive portion is scratched (S118).
[0033]
If there is a pixel that has not been inspected for scratches on the main photosensitive portion and the secondary photosensitive portion, the process returns to step S106 in step S120. If the inspection is completed for all the pixels, the process is terminated.
[0034]
In the present invention, in the exposure (S102), the main photosensitive portion and the secondary photosensitive portion may be exposed with different exposure times. For example, as shown in FIG. 5, the main photosensitive portion data read pulse rises in response to the first timing pulse after the driving of the electronic shutter (a) starts, and the secondary photosensitive portion in response to the second timing pulse. Data read pulse rises. As a result, the secondary photosensitive unit can detect weaker light because the exposure time is long.
[0035]
As a second embodiment, in the pixel defect inspection apparatus 10, when the system control unit 14 determines that there is a scratch on the main photosensitive unit, the system control unit 14 further compares the secondary photosensitive unit data with a predetermined threshold value, thereby The presence or absence of scratches may be determined. For example, as shown in FIG. 6, when it is determined that there is a scratch on the main photosensitive portion (S110), the scratch address of the main photosensitive portion is recorded on the recording unit 24 (step S115). Next, the slave photosensitive portion data is compared with a predetermined threshold value (step S604). For example, if Sub (y, x) / k / j <0.5 is positive using the output value k and the sensitivity ratio j described above, it is determined that the secondary photosensitive unit is not scratched (step S606) and negative. In this case, it is determined that the secondary photosensitive unit is scratched (step S608). Only when it is determined that there is a flaw in the sub-photosensitive portion (S608), the flaw address of the sub-photosensitive portion is recorded in the recording unit 24 (step S610).
[0036]
As a third embodiment, in the pixel defect inspection apparatus 10, when the system control unit 14 determines that there is no scratch on the main photosensitive unit, the system compares the secondary photosensitive unit data using the sensitivity ratio, and further compares the data with a predetermined threshold value. In comparison, the presence or absence of a flaw in the secondary photosensitive portion may be determined. For example, as shown in FIG. 7, when the determination is made that there is no scratch on the main photosensitive portion (S108), the slave photosensitive portion is compared with the main photosensitive portion data using the sensitivity ratio j to calculate an evaluation value A (step S702). For example, the evaluation value A is calculated by | Sub (y, x) × j−Main (y, x) |. Next, the slave photosensitive portion data is compared with a predetermined threshold value to calculate an evaluation value B (step S704). For example, the evaluation value B is calculated by Sub (y, x) / k / j. Next, in step (step S706), when αA + βB <δ is positive using predetermined comparison values α and β and threshold value δ, it is determined that the secondary photosensitive unit is not scratched (S114), and is negative. The secondary photosensitive unit is determined to be scratched (step S708).
[0037]
As another embodiment, the scratch detection method of the present invention can be applied to a digital camera. For example, as shown in FIG. 8, the digital camera is controlled by a control signal 802 from a system control unit 50, and a digital image signal 804 supplied from an A / D converter 52 is processed by a signal processing unit 54. For digital signal processing, digital image signals 806 and 808 subjected to the digital signal processing are supplied to the recording unit 56 and the display unit 58, respectively.
[0038]
In the present embodiment, the digital image signal 804 includes main photosensitive portion data and secondary photosensitive portion data, and the signal processing unit 54 has image memories 60 and 80 to store the primary photosensitive portion data and secondary photosensitive portion data. Each is temporarily stored as a main image signal and a sub image signal. The signal processing unit 54 includes a white balance (WB) gain unit 62 and a gamma (γ) conversion unit 64 that process the main image signal, and a WB gain unit 82 and a γ conversion unit 84 that process the sub image signal. Further, the image adding unit 66 that combines the main image signal and the sub-image signal is provided. The synchronization processing unit 68, various correction units 70, JPEG (Joint Photographic Experts Group) compression unit 72, and image reduction unit 74 are provided. Then, the synthesized main image signal is processed.
[0039]
Particularly in the present embodiment, the system control unit 50 controls the signal processing unit 54 with a control signal 802 to read, for example, main photosensitive portion data and secondary photosensitive portion data at the time of exposure from the image memories 60 and 80, respectively. Further, the above-described embodiment, that is, the flow as shown in FIG. 1, FIG. 6 or FIG. 7 is executed, and the main photosensitive portion and the secondary photosensitive portion are scratched from the read main photosensitive portion data and secondary photosensitive portion data. To detect.
[0040]
Here, the main photosensitive portion flaw correction data indicating the flaw address of the main photosensitive portion and the sub photosensitive portion flaw correction data indicating the flaw address of the sub photosensitive portion are created and stored in the ROM 92 in the system control unit 50. The system control unit 50 can correct the scratch on the main photosensitive portion data and the secondary photosensitive portion data at the time of shooting based on the scratch correction data.
[0041]
These scratch correction data may not be created every time during exposure, and may be created only at the first exposure after the power is turned on, for example. Further, the main photosensitive portion data and the secondary photosensitive portion data used in creating the defect correction data are not limited to the data at the time of exposure, and data at the time of photographing may be used. In addition, the various correction units 70 may correct the combined main image signal using these defect correction data.
[0042]
【The invention's effect】
As described above, according to the scratch detection method of the present invention, the main photosensitive portion data is compared with the predetermined threshold value, and then the secondary photosensitive portion data is compared with the sensitivity ratio thereof, so that the wide dynamic range solid-state imaging device is compared. It is possible to detect whether each of the main photosensitive portion and the secondary photosensitive portion is flawed, and can be effectively applied to inspection in shipping of the solid-state imaging device.
[0043]
Further, according to the present invention, it is possible to determine a scratch by increasing the amount of incident light in the slave photosensitive portion, and to perform a scratch determination with a high S / N without performing light amount adjustment and data fetching twice.
[0044]
Further, when the flaw detection method of the present invention is applied to a digital camera or the like, defects can be detected in each of the main photosensitive portion and the secondary photosensitive portion of each pixel, so that each of the primary photosensitive portion data and the secondary photosensitive portion data is detected. Appropriate correction can be made.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating an operation procedure of a pixel defect inspection apparatus to which a scratch detection method of the present invention is applied.
FIG. 2 is a block diagram showing an embodiment of a pixel defect inspection apparatus to which a scratch detection method according to the present invention is applied.
3 is a diagram exemplifying flaw detection conditions and results stored in a memory included in the pixel defect inspection apparatus according to the embodiment shown in FIG. 2;
4 is a diagram showing the relationship between the amount of incident light and the amount of signal charge in the main photosensitive portion and the secondary photosensitive portion in the solid-state imaging device included in the pixel defect inspection apparatus of the embodiment shown in FIG.
5 is a timing chart in the system control unit and the timing pulse generation unit when the exposure time of the slave photosensitive unit is made longer than that of the main photosensitive unit in the pixel defect inspection apparatus of the embodiment shown in FIG.
FIG. 6 is a flowchart for explaining the operation procedure of the defect detection method of the second embodiment in the pixel defect inspection apparatus to which the defect detection method according to the present invention is applied.
FIG. 7 is a flowchart for explaining the operation procedure of the defect detection method of the third embodiment in the pixel defect inspection apparatus to which the defect detection method according to the present invention is applied.
FIG. 8 is a block diagram showing in detail a signal processing unit included in a digital camera to which a scratch detection method according to the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Pixel defect inspection apparatus 12 Optical lens system 14 System control part 16 Timing pulse generation part 18 Solid-state image sensor 20 Signal processing part 22 Memory 24 Recording part 26 Interface 28 Information recording medium

Claims

Using a solid-state imaging device that forms each pixel by arranging a first photosensitive portion that photoelectrically converts incident light and a second photosensitive portion that photoelectrically converts incident light with a lower sensitivity than the first photosensitive portion, In a pixel defect inspection apparatus for inspecting defects in the first photosensitive section and the second photosensitive section, the apparatus includes:
Exposure means for exposing the solid-state imaging device to obtain a first image signal and a second image signal from the first photosensitive portion and the second photosensitive portion, respectively;
A first determination unit that compares the first image signal using a first threshold and determines whether or not the first photosensitive portion has a scratch;
A second determination unit configured to compare the second image signal using a sensitivity ratio between the first photosensitive unit and the second photosensitive unit to determine whether or not the second photosensitive unit is flawed; Including
If the result of the first determination means is no scratch determination, the second determination means determines the presence or absence of a scratch on the second photosensitive part, and if the scratch determination is on the second photosensitive part, the second photosensitive part is scratched. A pixel defect inspection apparatus characterized by determining.

The pixel defect inspection apparatus according to claim 1, wherein the exposure unit exposes the solid-state imaging device using an incident light amount near a saturation level of the first photosensitive portion.

3. The pixel defect inspection apparatus according to claim 1, wherein the exposure unit exposes the second photosensitive portion with an exposure time longer than that of the first photosensitive portion to obtain a second image signal. A pixel defect inspection apparatus.

4. The pixel defect inspection apparatus according to claim 1, wherein the apparatus records a flaw address of the first photosensitive portion determined to be flawed, and a flaw of the second photosensitive portion determined to be flawed. A pixel defect inspection apparatus comprising a recording means for recording an address.

5. The pixel defect inspection apparatus according to claim 4, wherein the recording unit records the sensitivity ratio.

6. The pixel defect inspection apparatus according to claim 1, wherein the apparatus makes planar light incident on the solid-state imaging device, and uses the first image signal and the second image signal in advance to obtain the sensitivity. A pixel defect inspection apparatus characterized by measuring a ratio.

7. The pixel defect inspection apparatus according to claim 1, wherein the apparatus uses a representative design value as the sensitivity ratio.

8. The pixel defect inspection apparatus according to claim 1, wherein the exposure unit controls the output of the first photosensitive portion to k [mV], and the first image signal Main (y, x) and Obtain the second image signal Sub (y, x),
The first determination means uses the first threshold value k to determine that the first photosensitive portion is not scratched when Main (y, x) / k <0.1 is positive, and when negative, Determines that the first photosensitive area is scratched,
The second determination means uses the sensitivity ratio j and the second threshold value ε, and when | Sub (y, x) × j−Main (y, x) | <ε is positive, A pixel defect inspection apparatus, characterized in that it is determined that there is no flaw in the part, and that the second photosensitive part is flawed if it is negative.

9. The pixel defect inspection apparatus according to claim 1, wherein the apparatus compares the second image signal using the first threshold value to determine whether or not the second photosensitive portion is damaged. Including third determination means for determining
3. A pixel defect inspection apparatus, wherein when the result of the first determination means is a flaw determination, the third determination means determines the presence or absence of a flaw in the second photosensitive portion.

10. The pixel defect inspection apparatus according to claim 9, wherein the exposure unit controls the output of the first photosensitive portion to k [mV], and the first image signal Main (y, x) and the second image signal. Sub (y, x)
The third determination means uses the first threshold value k and the sensitivity ratio j, and when the sub (y, x) / k / j <0.5 is positive, the second photosensitive portion is not scratched. A pixel defect inspection apparatus, characterized in that, if negative, it is determined that there is a scratch on the second photosensitive portion.

11. The pixel defect inspection apparatus according to claim 9, wherein the second determination unit compares the second image signal using the sensitivity ratio, and compares the second image signal using the first threshold value. Then, the pixel defect inspection apparatus characterized by determining whether or not the second photosensitive portion has a scratch.

12. The pixel defect inspection apparatus according to claim 11, wherein the exposure unit controls the output of the first photosensitive portion to k [mV], and the first image signal Main (y, x) and the second image signal. Sub (y, x)
The second determination means calculates the evaluation value A from the relationship of | Sub (y, x) × j-Main (y, x) | using the first threshold value k and the sensitivity ratio j, and sub ( The evaluation value B is calculated from the relationship of y, x) / k / j,
Using the predetermined coefficients α and β and the third threshold value δ, if αA + βB <δ is positive, it is determined that there is no scratch on the second photosensitive part, and if negative, the second photosensitive part is scratched. A pixel defect inspection device characterized by being determined to be present.

Using a solid-state imaging device that forms each pixel by arranging a first photosensitive portion that photoelectrically converts incident light and a second photosensitive portion that photoelectrically converts incident light with a lower sensitivity than the first photosensitive portion, In the scratch detection method for inspecting a defect of the first photosensitive portion and the second photosensitive portion, the method includes:
Exposing the solid-state imaging device to obtain a first image signal and a second image signal from the first photosensitive portion and the second photosensitive portion, respectively;
A first determination step of comparing the first image signal using a first threshold value to determine whether or not there is a scratch on the first photosensitive portion;
A second determination step of comparing the second image signal using a sensitivity ratio between the first photosensitive portion and the second photosensitive portion to determine whether or not the second photosensitive portion is damaged. Including
If the result of the first determination step is a determination that there is no flaw, the second determination step determines whether the second photosensitive portion is flawed. If the flaw is determined, the second photosensitive portion is flawed. A scratch detection method characterized by determining.

14. The scratch detection method according to claim 13, wherein the exposure step exposes the solid-state imaging device using an incident light amount near a saturation level of the first photosensitive portion.

15. The scratch detection method according to claim 13, wherein the exposure step exposes the second photosensitive portion with an exposure time longer than that of the first photosensitive portion to obtain a second image signal. Scratch detection method.

16. The flaw detection method according to claim 13, wherein the method records a flaw address of the first photosensitive portion determined to be flawed, and a flaw address of the second photosensitive portion determined to be flawed. A flaw detection method comprising a recording step of recording.

17. The scratch detection method according to claim 16, wherein the recording step records the sensitivity ratio.

The scratch detection method according to any one of claims 13 to 17, wherein the method is configured such that planar light is incident on the solid-state imaging device, and the sensitivity ratio is obtained in advance using a first image signal and a second image signal. A flaw detection method characterized by measuring the above.

The scratch detection method according to claim 13, wherein a representative design value is used as the sensitivity ratio.

20. The scratch detection method according to claim 13, wherein in the exposure step, the output of the first photosensitive portion is controlled to k [mV], and the first image signal Main (y, x) and the first output are controlled. 2 image signal Sub (y, x)
The first determination step uses the first threshold value k to determine that the first photosensitive portion is not scratched when Main (y, x) / k <0.1 is positive, and when negative, Determines that the first photosensitive area is scratched,
The second determination step uses the sensitivity ratio j and the second threshold value ε, and when | Sub (y, x) × j−Main (y, x) | <ε is positive, A scratch detection method characterized in that it is determined that there is no scratch on the part, and if it is negative, the second photosensitive part is determined to be scratched.

21. The scratch detection method according to any one of claims 13 to 20, wherein the method compares the second image signal using the first threshold value to determine whether the second photosensitive portion is scratched. Including a third determination step of determining,
A scratch detection method characterized by determining whether or not there is a scratch on the second photosensitive portion in a third determination step when the result of the first determination step is a scratch determination.

23. The scratch detection method according to claim 21, wherein in the exposure step, the output of the first photosensitive portion is controlled to k [mV], and the first image signal Main (y, x) and the second image signal Sub. (Y, x)
The third determination step uses the first threshold value k and the sensitivity ratio j, and when the sub (y, x) / k / j <0.5 is positive, the second photosensitive unit is not scratched. A scratch detection method comprising: determining, and if negative, determining that the second photosensitive portion is scratched.

23. The scratch detection method according to claim 21, wherein the second determination step compares the second image signal using the sensitivity ratio, and compares the second image signal using the first threshold. And determining whether there is a scratch on the second photosensitive portion.

24. The scratch detection method according to claim 23, wherein in the exposure step, the output of the first photosensitive portion is controlled to k [mV], and the first image signal Main (y, x) and the second image signal Sub. (Y, x)
The second determination step uses the first threshold value k and the sensitivity ratio j to calculate the evaluation value A from the relationship | Sub (y, x) × j−Main (y, x) | The evaluation value B is calculated from the relationship of y, x) / k / j,
Using the predetermined coefficients α and β and the third threshold value δ, if αA + βB <δ is positive, it is determined that there is no scratch on the second photosensitive part, and if negative, the second photosensitive part is scratched. A scratch detection method characterized by determining that there is.

Signal processing means for performing signal processing on the first image signal obtained from the high-sensitivity first photosensitive part and the second image signal obtained from the low-sensitivity second photosensitive part;
The signal processing means includes a first storage means for storing a first image signal and a second storage means for storing a second image signal.
The signal processing means compares the first image signal at the time of exposure using a first threshold value, and determines whether or not the first photosensitive portion has a flaw,
A second determination is made by comparing the second image signal at the time of exposure using the sensitivity ratio between the first photosensitive portion and the second photosensitive portion to determine whether or not the second photosensitive portion is flawed. Means,
When the result of the first determination means is a determination that there is no scratch, the second determination means determines the presence or absence of a scratch on the second photosensitive portion, and when the determination is that there is a scratch, it is determined that the second photosensitive portion is scratched. A digital camera characterized by that.

26. The digital camera according to claim 25, wherein the camera compares the second image signal at the time of exposure using the first threshold value, and determines whether or not the second photosensitive portion is damaged. 3 determination means,
A digital camera characterized in that when the result of the first determination means is a flaw determination, the third determination means determines the presence or absence of a flaw in the second photosensitive portion.

27. The digital camera according to claim 26, wherein the second determination means compares the second image signal at the time of exposure using the sensitivity ratio, and uses the first threshold value for the second image signal at the time of exposure. A digital camera characterized in that it is determined whether or not the second photosensitive portion is flawed.

28. The digital camera according to claim 25, wherein the camera generates first flaw correction data indicating a flaw address of the first photosensitive portion determined to be flawed, and the first flaw determined to be flawed. A digital camera characterized in that second defect correction data indicating a defect address of the second photosensitive portion is created.

29. The digital camera according to claim 28, wherein the camera corrects the first image signal at the time of shooting with the first scratch correction data, and converts the second image signal at the time of shooting to the second scratch correction data. A digital camera characterized by correcting with.