JP2004233480A

JP2004233480A - Stereoscopic endoscope system

Info

Publication number: JP2004233480A
Application number: JP2003019775A
Authority: JP
Inventors: Moriyasu Kanai; 守康金井
Original assignee: Pentax Corp
Current assignee: Pentax Corp
Priority date: 2003-01-29
Filing date: 2003-01-29
Publication date: 2004-08-19
Anticipated expiration: 2023-01-29
Also published as: JP4246510B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stereoscopic endoscope system capable of realizing a stable stereoscopic vision during a sergery operation or the like. <P>SOLUTION: This system is provided with: a rigid scope 10 which has a first and a second CCD 15, 16; and a signal processor 30 to which a monitor 40 and the rigid scope 10 are connected. Then, optical magnification m and electric enlargement ratio M are determined so as to satisfy the following equation. 0.00102 ≤ ¾M×m×p×Δs/(s×L)¾ ≤ 0.0091, where M is an electric enlargement ratio, m is an optical magnification, p is half a distance of the entrance pupil interval, s is a distance from a focal point position to the tip end of the endoscope, Δs is a depth of field, and L is a distance from a viewer to the display screen. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、視差のある左右の像を得ることが可能な撮像システムを有し、その２つの像に基づいて立体視用画像を画面に表示する立体表示システムに関し、特に、観察部位を立体視しながら手術等を行うことができる立体内視鏡システムに関する。
【０００２】
【従来の技術】
従来、視差を有する左右の像が得られるように観察部位を撮像し、その視差のある像（視差画像）を表示させて立体視を可能にする立体表示システムが知られている。特に、開腹等をせずに内視鏡を使用して手術をする「低浸襲手術」において、観察部位を立体視することが可能な立体内視鏡システムが知られている（例えば、特許文献１）。特許文献１では、立体内視鏡の先端部における画角αとＨＭＤ（ＨｅａｄＭｏｕｎｔＤｉｓｐｌａｙ）の視角βの条件式が示されており、さらに、奥行き感を得るための入射瞳間隔Ｅと内視鏡挿入部の外径Ｄとの関係が明らかにされている。
【０００３】
【特許文献１】
特開平８−３１３８２８号公報
（段落〔００２３〕〜〔００３２〕、第３−４図）
【０００４】
【発明が解決しようとする課題】
特許文献１では、先端部から観察部位までの距離をＸ、先端部の外径Ｄとした場合、ＸとＤとの関係が、“Ｘ＝２Ｄ”と規定されている。しかしながら、内視鏡を使用して縫合や止血クリッピングを行う場合、観察部位までの距離は術者の作業状況によって変わるため、特許文献１に示された条件では、術中において奥行き感を得るのが難しく、効率よく適切に手術を行うことができない。
【０００５】
そこで本発明では、術中等に安定して立体視することが可能な立体内視鏡システムおよび立体表示システムを得ることを目的とする。
【０００６】
【課題を解決するための手段】
本発明の立体内視鏡システムは、視差のある２つの像を形成し、立体視可能となるように立体視用画像を表示する立体内視鏡システムであり、手術下において術者が十分に立体視できるように構成されている。立体内視鏡システムの１つの構成としては、立体視用内視鏡と立体視用の画像信号処理装置とが備えられ、例えば２眼２カメラ方式の硬性鏡と、シャッタ機能付き眼鏡を用いた立体表示方式による画像処理装置とが設けられる。本発明の１つの特徴を示す立体内視鏡システムは、被写体を立体視可能にするため一対の撮像素子を有する撮像部と、１つの被写体から視差のある一対の像を形成し、一対の撮像素子に結像させる光学系と、撮像素子から読み出される一対の像に応じた一対の画像信号に基づいて、立体視用画像を表示装置に表示させる信号処理手段とを備える。
【０００７】
本発明の立体内視鏡システムは、以下の式を満たすことを特徴とする。
０．００１０２ ≦ ｜Ｍ×ｍ×ｐ×Δｓ／（ｓ×Ｌ）｜ ≦ ０．００９１
ここで、Ｍは電気的拡大率、ｍは内視鏡内に設けられた光学系の光学倍率、ｐは光学系における入射瞳間隔の半分の距離、ｓは焦点位置から内視鏡先端までの距離、Δｓは被写体の奥行き間隔、そして、Ｌは観察者から表示画面までの距離を示す。なお、電気的拡大率Ｍは、立体視用内視鏡内に設けられた撮像素子に形成される被写体像と表示画面に表示される被写体像との大きさ（サイズ）に関する比を示す。この式の下限値は、従来の開腹手術下において術者が知覚している立体感と同等の立体感（奥行き感）を最低限感じさせる必要があるとの考えにより定められており、奥行き間隔を過度に強調して立体視することが困難になる閾値を上限値として定めている。
【０００８】
一方、ビュアー方式による本発明の立体内視鏡システムは、拡大観察用光学系を介して立体視される立体内視鏡システムであって、拡大観察用光学系は、表示装置の立体視用画像を光学的に拡大する。この場合、立体内視鏡システムは、以下の式を満たすことを特徴とする。
０．００１０２ ≦｜Ｍ×ｍ×ｐ×Δｓ／（ｓ×Ｌ’）｜ ≦ ０．００９１
ただし、Ｌ’は拡大観察用光学系による仮想の観察者から表示画面までの距離を示す。
【０００９】
本発明の立体表示システムは、視差のある２つの像を形成し、立体視可能となるように立体視用画像を表示する立体表示システムであって、内視鏡の有無に関係なく立体表示可能である。立体表示システムは、以下の式を満たすことを特徴とする。
０．００１０２ ≦ ｜Ｍ×ｍ×ｐ×Δｓ／（ｓ×Ｌ）｜ ≦ ０．００９１
また、ビュアー方式による立体表示システムは、以下の式を満たすことを特徴とする。
０．００１０２ ≦｜Ｍ×ｍ×ｐ×Δｓ／（ｓ×Ｌ’）｜ ≦ ０．００９１
【００１０】
【発明の実施の形態】
以下では、図面を用いて、本発明の実施形態である立体内視鏡システムについて説明する。
【００１１】
図１は、本実施形態である立体内視鏡システムのブロック図である。本実施形態の立体内視鏡システムは、腹部などに硬性鏡を挿入し、立体視しながら手術を行うための内視鏡システムである。
【００１２】
立体内視鏡システムは、硬性鏡１０、信号処理装置３０、立体映像表示用のモニタ４０を備えており、硬性鏡１０は信号処理装置３０に接続されている。硬性鏡１０は、挿入部１２および撮像部１４から構成されており、患部を立体的に観察可能にする２眼２カメラ方式の電子内視鏡である。挿入部１２には、対物レンズ１１Ａ、１１Ｂ、および光学像を撮像部１４まで伝達する中継用（リレー）光学系１３Ａ、１３Ｂが設けられている。
【００１３】
硬性鏡１０の先端部１２Ｓに設けられた対物レンズ１１Ａは観察者の左目用の観察像（以下では、第１の観察像という）を形成する。そして、第１の観察像に応じた光はリレー光学系１３Ａを介して撮像部１４へ伝達される。一方、対物レンズ１１Ｂは右目用の観察像（以下では、第２の観察像という）を形成し、第２の観察像に応じた光はリレー光学系１３Ｂを介して撮像部１４へ伝達される。
【００１４】
撮像部１４には、反射ミラー１７Ａ、１７Ｂ、１８Ａ、１８Ｂ、第１のＣＣＤ（Ｃｈａｒｇｅ−ＣｏｕｐｌｅｄＤｅｖｉｃｅ）１５、第２のＣＣＤ１６、およびズームレンズ１９Ａ、１９Ｂが設けられており、第１の観察像に応じた光は、反射ミラー１７Ａ、１８Ａにおいて反射され、第１のズームレンズ１９Ａを介して第１のＣＣＤ１５に到達する。これにより、第１の観察像がＣＣＤ１５に形成され、画像信号が発生する。発生した画像信号（以下では、第１の画像信号という）は撮像部１４から読み出され、信号処理装置３０へ送られる。同様に、第２の観察像に応じた光は、反射ミラー１７Ｂ、１８Ｂ、第２のズームレンズ１９Ｂを介して第２のＣＣＤ１６に到達し、第２の観察像が第２のＣＣＤ１６上に形成され、画像信号（以下では、第２の画像信号という）が信号処理装置３０へ送られる。
【００１５】
信号処理装置３０には、第１信号処理部３２、第２信号処理部３３、映像同期部３４、制御部３５が設けられており、第１の画像信号、第２の画像信号は、それぞれ第１信号処理部３２、第２信号処理部３３へ送られる。第１信号処理部３２、第２信号処理部３３では、それぞれ第１の画像信号、第２の画像信号に対して所定の処理が施される。処理された画像信号は、映像同期部３４へ送られる。
【００１６】
本実施形態では、シャッタ付き眼鏡および時系列表示により立体視を実現させており、観察者はシャッタ機能付き眼鏡（図示せず）を掛けて立体視する。映像同期部３４では、第１の観察像および第２の観察像がモニタ４０上において交互に時系列表示されるように、第１の画像および第２の画像信号が所定のタイミングで出力される。また、映像同期部３４では、１画面上において第１の観察像と第２の観察像とが両眼視差に応じた距離だけ相対的にずれて表示されるように、信号処理が施される。シャッタ機能付き眼鏡では、映像同期部３４から出力される第１および第２の画像信号の出力タイミングと同期して左目用シャッタおよび右目用シャッタが交互に切り替えられる。その結果、硬性鏡１０によって捉えられた観察部位が立体視される。
【００１７】
硬性鏡１０の操作部にはズーム操作用レバー２１が備えられており、ズーム操作用レバー２１が操作されると、第１、第２レンズ駆動機構２２Ａ、２２Ｂが動き、操作量に従ってそれぞれ第１、第２のズームレンズ１９Ａ、１９Ｂを光軸に沿って移動させる。これにより、硬性鏡１０の光学的倍率が変動する。一方、制御部３５は、信号処理装置３０の動作を制御しており、後述するように電気的拡大率を設定可能である。オペレータが硬性鏡１０の光学倍率を設定するためキーボード３９を操作すると、それに応じて電気的拡大率が設定される。
【００１８】
図２は、モニタ画面と観察者との立体視関係を示した図であり、図３は、硬性鏡先端部１２Ｓおよび観察部位における光の軌跡を示した図である。図２、図３を用いて、術中において立体視するための立体内視鏡システムの条件について説明する。
【００１９】
まず、立体内視鏡システムを使用した手術において、医師等の観察者が１つの画面上の立体視用画像から観察部位を３次元的に知覚することができるための条件を求める。
【００２０】
図２に示すように、モニタ４０の表示画面４０Ｓと観察者ＯＨとの距離（以下では、表示距離という）を“Ｌ”，眼福の半分の距離を“ｑ”と表す。また、観察対象はオペレータＯＨの真正面上に知覚されるものとする。すなわち、観察者ＯＨの正面（左目ＬＥ、右目ＲＥの二等分線となる中心線ＧＨ）に観察対象が立体視されるように立体視用映像が画面４０Ｓに表示される。立体視用画像によって観察対象が３次元的に知覚されている場合、その観察対象の先端位置（以下では仮想先端位置という）を“Ｐ”と表し、画面４０Ｓ上にあって中心線ＧＨ上にある観察対象点を“Ｐ１”と表す。また、表示画面４０Ｓからの距離、すなわち観察対象の奥行き（以下では、仮想奥行き距離という）を“ΔＬ”と表す。
【００２１】
本実施形態では、硬性鏡１０によって撮像された観察対象は、「距離Ｌだけ離れ、“ΔＬ”だけ奥行きがある」物体として立体視される。そして、そのような立体感を知覚できる立体視用映像がモニタ４０に表示される必要があり、表示画面４０Ｓには、左目用の第１の観察像と右目用の第２の観察像とが両眼視差に応じたずれをもって交互に表示される。このとき、第１の観察像と第２の観察像との間における視差によるずれ量の半分の距離（以下では、表示側視差という）を“ΔＹ”とする。表示側視差ΔＹは、中心線ＧＨからのずれた距離に相当する。
【００２２】
ここで、左目ＬＥから仮想先端位置Ｐを通る視線Ｘ１が表示画面４０Ｓ上に到達する点をＱ１、右目ＲＥから仮想先端位置Ｐを通る視線Ｘ２が表示画面４０Ｓに到達する点をＱ２とする。仮想先端位置Ｐおよび、Ｑ１、Ｑ２を結ぶことで構成される三角形Ｓ１と、仮想物体先端Ｐおよび左目ＬＥ，右目ＲＥを結ぶことで構成される三角形Ｓ２は、相似関係にある。したがって、以下の式が成り立つ。
ΔＹ／ΔＬ＝ｑ／Ｌ・・・・（１１）
（１１）式により、表示側視差ΔＹは、以下の式に従って定められる。
ΔＹ＝ｑ×ΔＬ／Ｌ・・・・（１２）
【００２３】
次に、図３を用いて、実際に観察対象を硬性鏡１０により撮像した場合に得られる左右の像のずれを求める。ただし、説明を簡単にするため、光学系としては１つの対物レンズ１１Ａ、１１Ｂのみ表す。
【００２４】
図３に示すように、観察対象となる部位の先端位置を“Ｚ１”、対物レンズ１１Ａ、１１Ｂから先端位置Ｚ１までの距離を“ｓ”、観察部位の奥行きを“Δｓ”、観察部位の先端部１２Ｓから一定距離だけ離れた位置（以下では、最後尾位置という）を“Ｚ２”とする。また、入射瞳間隔（基線長）の半分の距離を“ｐ”、対物レンズ１１Ａ、１１Ｂを結ぶ部線ＧＧから第１および第２のＣＣＤ１５、１６までの像距離を“ｓ’”と表す。観察部位は対物レンズ１１Ａ、１１Ｂの中心を通る基準線Ｋ上にあるものとする。距離ｓは、対物レンズ１１Ａ、１１Ｂの焦点距離に対し十分大きいとき実質的に先端部１２Ｓと観察部位までの距離に等しいため、以下では被写体距離を“ｓ”とする。
【００２５】
観察対象の奥行きΔｓにより、第１のＣＣＤ１５、および第２のＣＣＤ１６の受光面上では、先端位置Ｚ１に応じた像の位置と最後尾位置Ｚ２に応じた像の位置とが異なる。ここでは、この距離（以下では、撮像側視差という）を“Δｙ”で表す。表示側視差ΔＹ（図２参照）の大きさは、この撮像側視差Δｙに比例する。
【００２６】
内視鏡を使用した手術下において、被写体距離ｓは、観察対象の奥行きΔｓに比べて十分長く、Δｓ≪ｓとみなせる。よって、基準線Ｋと最後尾位置Ｚ２から第２のＣＣＤ１６へ到達する光線Ｒ２ととの角度を“θ’”とすると、θ’は入射瞳間隔の半分の距離をｐ、被写体距離ｓを用いて以下のように表される。
θ’≒ θ ＝ｐ／ｓ・・・・・・（１３）
【００２７】
先端位置Ｚ１から対物レンズ１１Ｂを通って第２のＣＣＤ１６に到達する光線を“Ｒ１”とし、先端位置Ｚ１を含む断面における光線Ｒ１と光線Ｒ２との距離を“Δｈ”とする。ΔｈはΔｓ、θ’を用いて以下のように表される。
Δｈ＝Δｓ×θ’≒ Δｓ×ｐ／ｓ・・・・（１４）
また、光学系全体の倍率を“ｍ”とすると、光学倍率ｍは、被写体距離ｓと像距離ｓ’あるいは撮像側視差ΔｙとΔｈを用いて以下のように表される。
ｍ＝ｓ’／ｓ＝ Δｙ／Δｈ・・・・（１５）
【００２８】
したがって、（１４）（１５）式より、Δｙは、ｍ、ｐ、Δｓ、ｓを用いて次式のように表される。
Δｙ＝ｍ×ｐ×Δｓ／ｓ・・・（１６）
第１の撮影光学系１１Ａ、第１のＣＣＤ１５に関しても、同様に撮像側視差Δｙが求められる。
【００２９】
なお、ｓ’≪ｓの場合、ｓ’は実質的に焦点距離ｆに等しい（ｓ’≒ ｆ）。したがって、Δｙは、以下のように焦点距離ｆを用いて表すことができる。
Δｙ＝（ｓ’／ｓ）×ｐ×Δｓ／ｓ
＝ｆ×ｐ×Δｓ／ｓ^２・・・・（１７）
【００３０】
ここで、第１、第２のＣＣＤ１５、１６に結像される像の大きさに対するモニタ４０上の表示画像との比を電気的拡大率“Ｍ”とした場合、ΔＹとΔｙは以下の関係を満たす。
ΔＹ＝｜Δｙ×Ｍ｜・・・・（１８）
したがって、上記（１２）、（１７）、（１８）式より、以下の関係式が導かれる。
ΔＹ＝ｑ×ΔＬ／Ｌ＝｜Ｍ×ｍ×ｐ×Δｓ／ｓ｜・・（１９）
【００３１】
さらに、（１９）式の両辺に１／Ｌを乗じることにより、（１９）式は以下のように無次元化して表すことができる。
ΔＹ／Ｌ＝（ｑ×ΔＬ）／Ｌ^２
＝｜Ｍ×ｍ×ｐ×Δｓ／（ｓ×Ｌ）｜・・・（２０）
ΔＹが表示側視差を示すことから、ΔＹ／Ｌは視差角を表すものとみなせる。表示側視差ΔＹが大きいほど、あるいは表示距離Ｌが小さいほど立体感が得られることから、“ΔＹ／Ｌ”は立体感を表す係数と定義できる。眼福の半分の距離ｑはおよそ一定とみなせることから、表示距離Ｌと仮想奥行き距離ΔＬとの関係に従って“ΔＹ／Ｌ”の値は変化する。
【００３２】
ここで、立体内視鏡システムを利用している状況下においてオペレータに最低限必要な立体感を考える。内視鏡を使用しない開腹手術の下では、術者の眼球位置から観察物体までの距離は、腕を伸ばした長さほどの距離に相当し、およそ５００ｍｍである。さらに、開腹術では主に縫合作業が行われるが、そのとき使用される針の大きさは、平均的に８〜１０ｍｍ程度である。本実施形態では、このような開腹手術下で知覚できる立体感（奥行き感）をオペレータにとって最低限必要な立体感とみなす。すなわち、少なくとも開腹手術により得られる立体感と同等と立体感を立体内視鏡システムによって提供できるように（２０）式の下限値を定める。
【００３３】
眼福の半分の距離ｑは平均３２ｍｍである。（２０）式においてｑ＝３２、Ｌ＝５００、ΔＬ＝８を代入すると、（２０）式の下限値が以下のように求められる。
（ｑ×ΔＬ）／Ｌ^２＝３２×８／５００^２＝０．００１０２・・（２１）
よって、次式が導かれる。
０．００１０２ ≦ ｜Ｍ×ｍ×ｐ×（Δｓ／ｓ）×Ｌ｜・・（２２）
【００３４】
一方、光学倍率ｍあるいは電気的拡大率Ｍを必要以上に大きくすると、システムの大型化や画質劣化を招く。さらに、奥行き感が過度に強調された立体視用画像をモニタ４０に表示させると、オペレータＯＨは画像の融合がしにくくなり、立体視が困難になる。そこで、（２０）式の上限値を以下の条件に基づいて算出する。
【００３５】
３０歳前後の人の近点は、最も眼球（観察者）に近い場所で６ディオプター（以下、Ｄで表す）程度である。人間の眼球における焦点調節機能（単眼視でも可能）と輻輳（両眼視による機能）とは連動して一体的に作用することから、この近点での両眼視差によるズレ量が、オペレータの観察可能な限界点とみなせる。（２０）式の左辺にＬ＝１６７（ｍｍ）を代入すると、以下のように（２０）式の上限値が求められる。
｜Ｍ×ｍ×ｐ×（Δｓ／（ｓ×Ｌ）｜ ≦ ０．００９１・・（２３）
本実施形態の立体内視鏡では、（２２）式かつ（２３）式を満たすように、光学倍率ｍ、電気拡大率Ｍが定められ、信号処理装置３０の制御部３５が電気拡大率Ｍを調整する。
【００３６】
ここで、（２２）、（２３）式を、光学的倍率ｍ、電気的拡大率Ｍ、入射瞳間隔の半分の距離ｐをパラメータとした式で表すことを考える。腹腔鏡手術の場合、立体視が要求される作業は主に縫合作業であり、針の大きさが８〜１０ｍｍ、観察部位までの距離は４０〜１００ｍｍである。したがって、Δｓ／ｓは、少なくとも１／１０あればよい。Δｓ＝１０、ｓ＝１００とすると、以下の式が成り立つ。
１０．２ ≦ ｜（Ｍ×ｍ×ｐ）／Ｌ｜ ≦ ９１．０・・・（２４）
【００３７】
次に、図４を用いて第２の実施形態について説明する。第２の実施形態では、表示装置の前に光学系を配置するビュアー方式によって立体視される。それ以外の構成については、第１の実施形態と実質的に同じである。
【００３８】
図４は、第２の実施形態である立体内視鏡システムのブロック図である。
【００３９】
信号処理装置３０Ａには一対の表示装置４０Ａが接続されており、第１信号処理部３２から出力される第１の画像信号は第１の表示部４１へ出力され、第２信号処理部３３から出力される第２の画像信号は第１の表示部４２へ出力される。これにより、第１の表示部４１、第２の表示部４２にそれぞれ左目、右目用の視差のある画像が表示される。さらに、一対の表示装置４０ＡとオペレータＯＨとの間にはルーペＲＰが配置され、オペレータＯＨはルーペＲＰを介して立体視する。ルーペＲＰは左目用の第１レンズ４３、右目用の第２レンズ４４から構成され、第１の表示部４１、第２の表示部４２にそれぞれ表示された画像が拡大観察される。
【００４０】
ルーペＲＰは、仮想的に観察距離をルーペ焦点距離ｆｅ［ｍｍ］以下まで近づける機能をもつ。仮想の観察距離を“Ｌ’”と表した場合、仮想観察距離Ｌ’は以下の式で表される。ただし、仮想観察距離Ｌ’は、いわゆる機械近視（オペレータＯＨの視度が−１Ｄ）の状態に基づいて定められる。
Ｌ’＝ｆｅ−ｆｅ^２／１０００・・・（２５）
したがって、ビュアー方式の立体内視鏡システムでは、次式の関係が成り立つ。０．００１０２ ≦｜Ｍ×ｍ×ｐ×（Δｓ／（ｓ×Ｌ’）｜ ≦ ０．００９１
・・・（２６）
【００４１】
なお、立体表示方法については、第１、第２実施形態で示した表示方法以外の方法（例えば、ＨＭＤ方式など）によって立体視させてもよい。また、２眼２カメラ方式以外の立体視用硬性鏡（１眼２カメラ方式など）を使用してもよい。また、軟性鏡に適用することも可能である。
【００４２】
第１、第２実施形態では、開腹手術下の条件に従って（２２）式を導いているが、内視鏡を使用しない立体表示システムにも適用可能である。この場合、その立体表示システムが適用される環境（ロボット遠隔操作など）に従って上限値、下限値を求めればよい。
【００４３】
【発明の効果】
以上のように本発明によれば、術中等に安定して立体視することが可能である。
【図面の簡単な説明】
【図１】第１の実施形態である立体内視鏡システムのブロック図である。
【図２】モニタ画面と観察者との立体視関係を示した図である。
【図３】硬性鏡先端部および観察部位における光の軌跡を示した図である。
【図４】第２の実施形態である立体内視鏡システムのブロック図である。
【符号の説明】
１０硬性鏡
１１Ａ、１１Ｂ対物レンズ
１３Ａ、１３Ｂリレー系レンズ
１５第１のＣＣＤ
１６第２のＣＣＤ
１９Ａ、１９Ｂズームレンズ
３０、３０Ａ信号処理装置
４０、４０Ａモニタ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stereoscopic display system having an imaging system capable of obtaining left and right images with parallax, and displaying a stereoscopic image on a screen based on the two images. The present invention relates to a stereoscopic endoscope system capable of performing an operation or the like while operating.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a stereoscopic display system which captures an observation region so that left and right images having parallax are obtained, and displays an image having parallax (parallax image) to enable stereoscopic viewing. In particular, a stereoscopic endoscope system capable of stereoscopically observing a part to be observed in “low invasive surgery” in which an operation is performed using an endoscope without performing an abdomen or the like is known (for example, Patent Reference 1). Patent Document 1 discloses a conditional expression of an angle of view α and a viewing angle β of an HMD (Head Mount Display) at the distal end of a stereoscopic endoscope, and furthermore, an entrance pupil interval E and an endoscope for obtaining a sense of depth. The relationship with the outer diameter D of the mirror insertion portion is clarified.
[0003]
[Patent Document 1]
JP-A-8-313828 (paragraphs [0023] to [0032], FIG. 3-4)
[0004]
[Problems to be solved by the invention]
In Patent Literature 1, when the distance from the distal end to the observation site is X and the outer diameter D of the distal end is X, the relationship between X and D is defined as “X = 2D”. However, when performing suturing or hemostatic clipping using an endoscope, since the distance to the observation site varies depending on the work situation of the operator, it is difficult to obtain a sense of depth during the operation under the conditions shown in Patent Document 1. Difficult and unable to perform surgery efficiently and properly.
[0005]
Therefore, an object of the present invention is to provide a stereoscopic endoscope system and a stereoscopic display system capable of stably performing stereoscopic vision during an operation or the like.
[0006]
[Means for Solving the Problems]
The stereoscopic endoscope system of the present invention is a stereoscopic endoscope system that forms two images with parallax and displays a stereoscopic image so that the image can be stereoscopically viewed. It is configured to enable stereoscopic viewing. One configuration of the stereoscopic endoscope system includes a stereoscopic endoscope and a stereoscopic image signal processing device, and uses, for example, a two-lens two-camera rigid mirror and glasses with a shutter function. And an image processing apparatus using a stereoscopic display method. A stereoscopic endoscope system according to one aspect of the present invention includes an imaging unit having a pair of imaging elements for enabling a subject to be viewed stereoscopically, and forming a pair of images having parallax from one subject to form a pair of images. An optical system for forming an image on the element, and signal processing means for displaying a stereoscopic image on a display device based on a pair of image signals corresponding to a pair of images read from the imaging element.
[0007]
The stereoscopic endoscope system of the present invention is characterized by satisfying the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L) | ≦ 0.0091
Here, M is an electrical magnification, m is an optical magnification of an optical system provided in the endoscope, p is a half distance of an entrance pupil interval in the optical system, and s is a distance from a focus position to a tip of the endoscope. The distance, Δs indicates the depth interval of the subject, and L indicates the distance from the observer to the display screen. Note that the electrical magnification ratio M indicates a ratio of a subject image formed on an image sensor provided in the endoscope for stereoscopic vision to a subject image displayed on a display screen. The lower limit of this formula is determined based on the idea that it is necessary to make the operator feel at least a stereoscopic effect (depth effect) equivalent to the stereoscopic effect perceived by the operator under conventional laparotomy. Is excessively emphasized, and a threshold value at which stereoscopic viewing becomes difficult is determined as an upper limit value.
[0008]
On the other hand, the stereoscopic endoscope system of the present invention based on the viewer system is a stereoscopic endoscope system that is stereoscopically viewed through an optical system for magnifying observation, and the optical system for magnifying observation is a stereoscopic image of a display device. Is optically magnified. In this case, the stereoscopic endoscope system is characterized by satisfying the following equation.
0.00102 ≦ | M × m × p × Δs / (s × L ′) | ≦ 0.0091
Here, L 'indicates the distance from the virtual observer to the display screen by the magnifying observation optical system.
[0009]
The stereoscopic display system of the present invention is a stereoscopic display system that forms two images with parallax and displays a stereoscopic image so that stereoscopic viewing is possible. It is. The stereoscopic display system is characterized by satisfying the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L) | ≦ 0.0091
Further, the stereoscopic display system based on the viewer system is characterized by satisfying the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L ′) | ≦ 0.0091
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a stereoscopic endoscope system according to an embodiment of the present invention will be described with reference to the drawings.
[0011]
FIG. 1 is a block diagram of a stereoscopic endoscope system according to the present embodiment. The stereoscopic endoscope system of the present embodiment is an endoscope system for performing an operation while stereoscopically viewing by inserting a rigid endoscope into an abdomen or the like.
[0012]
The stereoscopic endoscope system includes a rigid endoscope 10, a signal processing device 30, and a monitor 40 for displaying a stereoscopic image, and the rigid endoscope 10 is connected to the signal processing device 30. The rigid endoscope 10 is a two-lens two-camera electronic endoscope that includes an insertion unit 12 and an imaging unit 14 and enables a three-dimensional observation of an affected part. The insertion section 12 is provided with objective lenses 11A and 11B and relay (relay) optical systems 13A and 13B for transmitting an optical image to the imaging section 14.
[0013]
The objective lens 11A provided at the distal end 12S of the rigid endoscope 10 forms an observation image for the left eye of the observer (hereinafter, referred to as a first observation image). Then, light corresponding to the first observation image is transmitted to the imaging unit 14 via the relay optical system 13A. On the other hand, the objective lens 11B forms an observation image for the right eye (hereinafter, referred to as a second observation image), and light corresponding to the second observation image is transmitted to the imaging unit 14 via the relay optical system 13B. .
[0014]
The imaging unit 14 includes reflection mirrors 17A, 17B, 18A, 18B, a first CCD (Charge-Coupled Device) 15, a second CCD 16, and zoom lenses 19A, 19B. Is reflected by the reflection mirrors 17A and 18A, and reaches the first CCD 15 via the first zoom lens 19A. As a result, a first observation image is formed on the CCD 15, and an image signal is generated. The generated image signal (hereinafter, referred to as a first image signal) is read from the imaging unit 14 and sent to the signal processing device 30. Similarly, the light corresponding to the second observation image reaches the second CCD 16 via the reflection mirrors 17B and 18B and the second zoom lens 19B, and the second observation image is formed on the second CCD 16 Then, an image signal (hereinafter, referred to as a second image signal) is sent to the signal processing device 30.
[0015]
The signal processing device 30 includes a first signal processing unit 32, a second signal processing unit 33, a video synchronization unit 34, and a control unit 35. The first image signal and the second image signal The signals are sent to the first signal processor 32 and the second signal processor 33. In the first signal processing unit 32 and the second signal processing unit 33, predetermined processing is performed on the first image signal and the second image signal, respectively. The processed image signal is sent to the video synchronization unit 34.
[0016]
In the present embodiment, stereoscopic vision is realized by glasses with shutters and time-series display, and the observer wears glasses with shutter functions (not shown) to perform stereoscopic vision. In the video synchronizing unit 34, the first image and the second image signal are output at a predetermined timing such that the first observation image and the second observation image are alternately displayed in time series on the monitor 40. . In the video synchronization unit 34, signal processing is performed such that the first observation image and the second observation image are displayed on one screen so as to be relatively shifted by a distance corresponding to the binocular disparity. . In the glasses with a shutter function, the left-eye shutter and the right-eye shutter are alternately switched in synchronization with the output timing of the first and second image signals output from the video synchronization unit 34. As a result, the observation site captured by the rigid endoscope 10 is stereoscopically viewed.
[0017]
The operation unit of the rigid endoscope 10 is provided with a zoom operation lever 21. When the zoom operation lever 21 is operated, the first and second lens driving mechanisms 22A and 22B move, and the first and second lens driving mechanisms 22A and 22B respectively move according to the operation amounts. Then, the second zoom lenses 19A and 19B are moved along the optical axis. Thereby, the optical magnification of the rigid endoscope 10 changes. On the other hand, the control unit 35 controls the operation of the signal processing device 30 and can set an electrical magnification as described later. When the operator operates the keyboard 39 to set the optical magnification of the rigid endoscope 10, the electric magnification is set accordingly.
[0018]
FIG. 2 is a diagram showing a stereoscopic relationship between a monitor screen and an observer, and FIG. 3 is a diagram showing a trajectory of light at a rigid end portion 12S and an observation site. The conditions of the stereoscopic endoscope system for stereoscopically viewing during surgery will be described with reference to FIGS. 2 and 3.
[0019]
First, in an operation using a stereoscopic endoscope system, a condition for an observer such as a doctor to be able to three-dimensionally perceive an observation region from a stereoscopic image on one screen is obtained.
[0020]
As shown in FIG. 2, the distance between the display screen 40S of the monitor 40 and the observer OH (hereinafter, referred to as the display distance) is represented by "L", and the distance of half of the eye is represented by "q". It is assumed that the observation target is perceived right in front of the operator OH. That is, the stereoscopic video is displayed on the screen 40S such that the observation target is stereoscopically viewed in front of the observer OH (the center line GH which is a bisector of the left eye LE and the right eye RE). When the observation target is three-dimensionally perceived by the stereoscopic image, the tip position of the observation target (hereinafter, referred to as a virtual tip position) is represented by “P”, and is displayed on the screen 40S and on the center line GH. A certain observation target point is represented as “P1”. The distance from the display screen 40S, that is, the depth of the observation target (hereinafter, referred to as a virtual depth distance) is represented as “ΔL”.
[0021]
In the present embodiment, the observation target imaged by the rigid endoscope 10 is stereoscopically viewed as an object that “is separated by a distance L and has a depth of“ ΔL ””. Then, it is necessary to display a stereoscopic image capable of perceiving such a stereoscopic effect on the monitor 40, and the display screen 40S includes a first observation image for the left eye and a second observation image for the right eye. The images are displayed alternately with a shift according to the binocular parallax. At this time, a distance (hereinafter, referred to as a display-side parallax) that is a half of the shift amount due to the parallax between the first observation image and the second observation image is “ΔY”. The display-side parallax ΔY corresponds to a distance deviated from the center line GH.
[0022]
Here, the point at which the line of sight X1 passing through the virtual tip position P from the left eye LE reaches the display screen 40S is Q1, and the point at which the line of sight X2 passing through the virtual tip position P from the right eye RE reaches the display screen 40S is Q2. A triangle S1 formed by connecting the virtual tip position P and Q1 and Q2 and a triangle S2 formed by connecting the virtual object tip P and the left eye LE and the right eye RE have a similar relationship. Therefore, the following equation holds.
ΔY / ΔL = q / L (11)
According to the equation (11), the display-side parallax ΔY is determined according to the following equation.
ΔY = q × ΔL / L (12)
[0023]
Next, using FIG. 3, the deviation between the left and right images obtained when the observation target is actually imaged by the rigid endoscope 10 is determined. However, for simplicity, only one objective lens 11A, 11B is shown as an optical system.
[0024]
As shown in FIG. 3, the tip position of the part to be observed is “Z1”, the distance from the objective lenses 11A and 11B to the tip position Z1 is “s”, the depth of the observation part is “Δs”, and the tip of the observation part is “Z1”. A position separated from the unit 12S by a certain distance (hereinafter, referred to as a tail position) is defined as “Z2”. Further, a distance that is a half of the entrance pupil interval (base line length) is represented by “p”, and an image distance from the part line GG connecting the objective lenses 11A and 11B to the first and second CCDs 15 and 16 is represented by “s ′”. The observation site is on a reference line K passing through the centers of the objective lenses 11A and 11B. The distance s is substantially equal to the distance between the tip 12S and the observation site when the distance s is sufficiently large with respect to the focal length of the objective lenses 11A and 11B.
[0025]
The position of the image corresponding to the front end position Z1 and the position of the image corresponding to the rearmost position Z2 are different on the light receiving surfaces of the first CCD 15 and the second CCD 16 depending on the depth Δs of the observation target. Here, this distance (hereinafter, referred to as imaging side parallax) is represented by “Δy”. The magnitude of the display-side parallax ΔY (see FIG. 2) is proportional to the imaging-side parallax Δy.
[0026]
Under the operation using the endoscope, the subject distance s is sufficiently longer than the depth Δs of the observation target, and can be regarded as Δs≪s. Therefore, assuming that the angle between the reference line K and the ray R2 reaching the second CCD 16 from the rearmost position Z2 is “θ ′”, θ ′ uses p as the distance of half of the entrance pupil distance and s as the object distance. Is expressed as follows.
θ ′ ≒ θ = p / s (13)
[0027]
The light beam that reaches the second CCD 16 from the tip position Z1 through the objective lens 11B is defined as “R1”, and the distance between the light beam R1 and the light beam R2 in the cross section including the tip position Z1 is defined as “Δh”. Δh is represented as follows using Δs and θ ′.
Δh = Δs × θ ′ ≒ Δs × p / s (14)
Further, assuming that the magnification of the entire optical system is “m”, the optical magnification m is expressed as follows using the subject distance s and the image distance s ′ or the imaging-side parallaxes Δy and Δh.
m = s' / s = Δy / Δh (15)
[0028]
Therefore, from equations (14) and (15), Δy is expressed as follows using m, p, Δs, and s.
Δy = m × p × Δs / s (16)
Similarly, the imaging-side parallax Δy is obtained for the first imaging optical system 11A and the first CCD 15.
[0029]
In the case of s'ｓs, s 'is substantially equal to the focal length f (s' ≒ f). Therefore, Δy can be expressed using the focal length f as follows.
Δy = (s ′ / s) × p × Δs / s
= F × p × Δs / s ² (17)
[0030]
Here, when the ratio of the size of the image formed on the first and second CCDs 15 and 16 to the display image on the monitor 40 is an electric magnification “M”, ΔY and Δy have the following relationship. Meet.
ΔY = | Δy × M | (18)
Therefore, the following relational expressions are derived from the above expressions (12), (17), and (18).
ΔY = q × ΔL / L = | M × m × p × Δs / s | (19)
[0031]
Further, by multiplying both sides of the expression (19) by 1 / L, the expression (19) can be expressed in a dimensionless manner as follows.
ΔY / L = (q × ΔL) / L ²
= | M × m × p × Δs / (s × L) | (20)
Since ΔY indicates the display-side parallax, ΔY / L can be regarded as representing the parallax angle. The larger the display-side parallax ΔY or the smaller the display distance L, the more the three-dimensional effect is obtained. Therefore, “ΔY / L” can be defined as a coefficient representing the three-dimensional effect. Since the distance q that is half of the eyesight can be regarded as substantially constant, the value of “ΔY / L” changes according to the relationship between the display distance L and the virtual depth distance ΔL.
[0032]
Here, consider the minimum stereoscopic effect required by the operator under the situation where the stereoscopic endoscope system is used. Under laparotomy without using an endoscope, the distance from the operator's eyeball position to the object to be observed is equivalent to the length of the extended arm, and is about 500 mm. Furthermore, suturing is mainly performed in laparotomy, and the size of the needle used at that time is about 8 to 10 mm on average. In the present embodiment, the three-dimensional effect (depth effect) that can be perceived under such a laparotomy is regarded as the minimum required three-dimensional effect for the operator. That is, the lower limit of the expression (20) is determined so that the stereoscopic endoscope system can provide a stereoscopic effect at least equivalent to the stereoscopic effect obtained by open surgery.
[0033]
The distance q that is half of the eyesight is 32 mm on average. By substituting q = 32, L = 500, and ΔL = 8 in equation (20), the lower limit of equation (20) is obtained as follows.
(Q × ΔL) / L ² = 32 × 8/500 ² = 0.00102 (21)
Therefore, the following equation is derived.
0.00102 ≦ | M × m × p × (Δs / s) × L | (22)
[0034]
On the other hand, if the optical magnification m or the electric magnification M is increased more than necessary, the system becomes large and the image quality deteriorates. Further, when a stereoscopic image in which the sense of depth is excessively emphasized is displayed on the monitor 40, it becomes difficult for the operator OH to fuse the images, and the stereoscopic vision becomes difficult. Therefore, the upper limit of the equation (20) is calculated based on the following conditions.
[0035]
The near point of a person around the age of 30 is about 6 diopters (hereinafter, referred to as D) at a position closest to the eyeball (observer). Since the focus adjustment function (possible even with monocular vision) and the convergence (function with binocular vision) in the human eyeball work in conjunction with each other, the amount of displacement due to binocular parallax at this near point is determined by the operator. It can be regarded as the observable limit. When L = 167 (mm) is substituted into the left side of Expression (20), the upper limit of Expression (20) is obtained as follows.
| M × m × p × (Δs / (s × L) | ≦ 0.0091 (23)
In the stereoscopic endoscope of the present embodiment, the optical magnification m and the electric magnification M are determined so as to satisfy the expressions (22) and (23), and the control unit 35 of the signal processing device 30 sets the electric magnification M to adjust.
[0036]
Here, it is considered that the expressions (22) and (23) are expressed by using the optical magnification m, the electric magnification M, and the distance p, which is a half of the entrance pupil interval, as parameters. In the case of laparoscopic surgery, operations requiring stereoscopic vision are mainly suturing operations, and the size of the needle is 8 to 10 mm, and the distance to the observation site is 40 to 100 mm. Therefore, Δs / s may be at least 1/10. If Δs = 10 and s = 100, the following equation holds.
10.2 ≦ | (M × mx × p) /L|≦91.0 (24)
[0037]
Next, a second embodiment will be described with reference to FIG. In the second embodiment, stereoscopic viewing is performed by a viewer system in which an optical system is arranged in front of a display device. Other configurations are substantially the same as those of the first embodiment.
[0038]
FIG. 4 is a block diagram of a stereoscopic endoscope system according to the second embodiment.
[0039]
A pair of display devices 40A is connected to the signal processing device 30A. The first image signal output from the first signal processing unit 32 is output to the first display unit 41, and the first image signal is output from the second signal processing unit 33. The output second image signal is output to the first display unit 42. Thereby, images having parallax for the left eye and the right eye are displayed on the first display unit 41 and the second display unit 42, respectively. Further, a loupe RP is arranged between the pair of display devices 40A and the operator OH, and the operator OH performs a stereoscopic view through the loupe RP. The loupe RP includes a first lens 43 for the left eye and a second lens 44 for the right eye, and the images displayed on the first display unit 41 and the second display unit 42 are magnified and observed.
[0040]
The loupe RP has a function of virtually reducing the observation distance to the loupe focal length fe [mm] or less. When the virtual observation distance is represented by “L ′”, the virtual observation distance L ′ is represented by the following equation. However, the virtual observation distance L 'is determined based on the state of so-called mechanical myopia (the diopter of the operator OH is -1D).
^{L '= fe-fe 2/} 1000 ··· (25)
Therefore, in the viewer-type stereoscopic endoscope system, the following relationship is established. 0.00102 ≦ | M × m × p × (Δs / (s × L ′) | ≦ 0.0091
... (26)
[0041]
As for the stereoscopic display method, stereoscopic viewing may be performed by a method other than the display method described in the first and second embodiments (for example, an HMD method). Further, a rigid stereoscope (such as a one-lens two-camera system) other than the two-lens two-camera system may be used. It is also possible to apply to a flexible endoscope.
[0042]
In the first and second embodiments, the expression (22) is derived according to the conditions under open surgery, but the present invention can also be applied to a stereoscopic display system that does not use an endoscope. In this case, the upper limit value and the lower limit value may be obtained according to the environment to which the stereoscopic display system is applied (such as remote operation of a robot).
[0043]
【The invention's effect】
As described above, according to the present invention, it is possible to perform a stereoscopic view stably during an operation or the like.
[Brief description of the drawings]
FIG. 1 is a block diagram of a stereoscopic endoscope system according to a first embodiment.
FIG. 2 is a diagram showing a stereoscopic relationship between a monitor screen and an observer.
FIG. 3 is a diagram showing a trajectory of light at a distal end portion of a rigid endoscope and an observation site.
FIG. 4 is a block diagram of a stereoscopic endoscope system according to a second embodiment.
[Explanation of symbols]
10 Rigid endoscope 11A, 11B Objective lens 13A, 13B Relay lens 15 First CCD
16 Second CCD
19A, 19B Zoom lens 30, 30A Signal processing device 40, 40A Monitor

Claims

In a stereoscopic endoscope system that forms two images with parallax and displays a stereoscopic image so that stereoscopic viewing is possible,
A stereoscopic endoscope system characterized by satisfying the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L) | ≦ 0.0091
・・・・・ (1)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the endoscope end, Δs is the depth interval of the subject, and L is the distance from the observer. Indicates the distance to the display screen.

In a stereoscopic endoscope system that forms two images with parallax and displays a stereoscopic image so that stereoscopic viewing is possible, and is stereoscopically viewed through an optical system for magnifying observation,
A stereoscopic endoscope system characterized by satisfying the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L ′) | ≦ 0.0091
.... (2)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the endoscope end, Δs is the depth interval of the subject, and L ′ is the magnification observation. The distance from the virtual observer to the display screen by the optical system is shown.

An imaging unit having a pair of imaging elements to enable a subject to be stereoscopically viewed,
An optical system that forms a pair of images having parallax from one subject and forms an image on the pair of imaging elements;
Signal processing means for displaying a stereoscopic image on a display device based on a pair of image signals corresponding to the pair of images read from the imaging element,
A stereoscopic endoscope system wherein an optical magnification of an optical system and an electric magnification in a signal processing unit are determined so as to satisfy the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L) | ≦ 0.0091
・・・・・ (3)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the end of the endoscope, Δs is the depth interval of the subject, and L is the display screen from the observer. Indicates the distance to.

An imaging unit having a pair of imaging elements to enable a subject to be stereoscopically viewed,
An optical system that forms a pair of images having parallax from one subject and forms an image on the pair of imaging elements;
Signal processing means for displaying a stereoscopic image on a display device based on a pair of image signals corresponding to the pair of images read from the image sensor,
An optical system for magnifying observation for optically enlarging a stereoscopic image of the display device, wherein an optical magnification of the optical system and an electric magnification in the signal processing unit are determined so as to satisfy the following expression. A stereoscopic endoscope system, characterized in that
0.00102 ≦ | M × m × p × Δs / (s × L ′) | ≦ 0.0091
... (4)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the endoscope end, Δs is the depth interval of the subject, and L ′ is the magnification observation. The distance from the virtual observer to the display screen by the optical system is shown.

The stereoscopic endoscope system according to any one of claims 1 to 4, wherein the stereoscopic endoscope system is a stereoscopic endoscope system using a two-lens two-camera system.

The stereoscopic endoscope system according to claim 2, wherein the magnifying observation optical system has a pair of loupes.

An image pickup unit having a pair of image sensors for enabling a subject to be viewed stereoscopically, and an optical system that forms a pair of images having parallax from one subject and forms an image on the pair of image pickup devices. An image processing apparatus of a stereoscopic endoscope system connected to an endoscope,
Signal processing means for generating a stereoscopic image signal based on a pair of image signals corresponding to the pair of images read from the image sensor,
Display means for displaying the stereoscopic image,
An image processing apparatus for a stereoscopic endoscope system, wherein an electrical magnification in the signal processing means is determined so as to satisfy the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L) | ≦ 0.0091
・・・・・ (5)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the endoscope end, Δs is the depth interval of the subject, and L is the distance from the observer. Indicates the distance to the display screen.

A stereoscopic endoscope connected to the image processing device of the stereoscopic endoscope system according to claim 7,
An imaging unit having a pair of imaging elements to enable a subject to be stereoscopically viewed,
An optical system that forms a pair of images having parallax from one subject and forms an image on the pair of imaging elements;
The stereoscopic endoscope, wherein an optical magnification of the optical system is determined so as to satisfy the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L) | ≦ 0.0091
・・・・・ (6)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the end of the endoscope, Δs is the depth interval of the subject, and L is the display screen from the observer. Indicates the distance to.

An image pickup unit having a pair of image sensors for enabling a subject to be viewed stereoscopically, and an optical system that forms a pair of images having parallax from one subject and forms an image on the pair of image pickup devices. An image processing apparatus of a stereoscopic endoscope system connected to an endoscope,
Signal processing means for generating a stereoscopic image signal based on a pair of image signals corresponding to the pair of images read from the image sensor,
Display means for displaying the stereoscopic image,
An optical system for magnifying observation for optically enlarging a stereoscopic image displayed by the display means,
An image processing apparatus for a stereoscopic endoscope system, wherein an electrical magnification in the signal processing means is determined so as to satisfy the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L ′) | ≦ 0.0091
... (7)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the endoscope end, Δs is the depth interval of the subject, and L ′ is the magnification observation. The distance from the virtual observer to the display screen by the optical system is shown.

A stereoscopic endoscope connected to the image processing device of the stereoscopic endoscope system according to claim 9,
An imaging unit having a pair of imaging elements to enable a subject to be stereoscopically viewed,
An optical system that forms a pair of images having parallax from one subject and forms an image on the pair of imaging elements;
The stereoscopic endoscope, wherein an optical magnification of the optical system is determined so as to satisfy the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L ′) | ≦ 0.0091
・・・・ (8)
Here, M is the electrical magnification, m is the optical magnification, p is the distance of half of the entrance pupil distance, s is the distance from the subject to the tip of the endoscope, Δs is the depth distance of the subject, and L ′ is the magnification observation optical. The distance from the virtual observer to the display screen by the system is shown.

An imaging unit having a pair of imaging elements to enable a subject to be stereoscopically viewed,
An optical system that forms a pair of images having parallax from one subject and forms an image on the pair of imaging elements;
Signal processing means for displaying a stereoscopic image on a display device based on a pair of image signals corresponding to the pair of images read from the image sensor,
A three-dimensional display system, wherein an optical magnification of the optical system and an electric magnification in the signal processing unit are determined so as to satisfy the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L) | ≦ 0.0091
・・・・・ (9)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the endoscope end, Δs is the depth interval of the subject, and L is the distance from the observer. Indicates the distance to the display screen.

An imaging unit having a pair of imaging elements to enable a subject to be stereoscopically viewed,
An optical system that forms a pair of images having parallax from one subject and forms an image on the pair of imaging elements;
Signal processing means for displaying a stereoscopic image on a display device based on a pair of image signals corresponding to the pair of images read from the image sensor,
An optical system for magnifying observation for optically enlarging a stereoscopic image of the display device,
A three-dimensional display system, wherein an optical magnification of the optical system and an electric magnification in the signal processing unit are determined so as to satisfy the following expression.
0.00102 ≦ | M × m × p × Δs / (s × L ′) | ≦ 0.0091
... (10)
Where M is the electrical magnification, m is the optical magnification, p is the distance of half the entrance pupil interval, s is the distance from the subject to the endoscope end, Δs is the depth interval of the subject, and L ′ is the magnification observation. The distance from the virtual observer to the display screen by the optical system is shown.