JP2004354435A - Stereoscopic imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stereoscopic imaging apparatus equipped with a stereoscopic imaging optical system made small in size and having a large viewing angle in the horizontal direction (parallax direction). <P>SOLUTION: The stereoscopic imaging apparatus has 1st and 2nd objective groups 1L and 1R arranged by leaving space in between and having negative refractive power, an image forming lens group 3 arranged in an optical path nearer to the side of a single imaging device 4 than the objective groups 1L and 1R and having positive refractive power, and 1st reflection surfaces 21L and 21R reflecting incident luminous flux on the objective groups 1L and 1R to the sides of the objective groups 1R and 1L on an opposite side and 2nd reflection surfaces 22L and 22R reflecting the luminous flux from the 1st reflection surfaces 21L and 21R to the side of the imaging device 4. The 2nd reflection surfaces 22L and 22R are arranged to reflect their reflected luminous flux to the side of a subject, and the imaging device 4 is arranged on the side of the reflected luminous flux by the 2nd reflection surfaces 22L and 22R. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０１２３】

【０１２４】

【０１２５】
以上の表１〜表３において、寸法を表す値の単位はｍｍである。
【０１２６】
以上にこの実施例のステレオ撮像光学系の左の光学系を説明したが、上記のように、右の光学系は、結像レンズ群３を共有し、右の対物レンズ群１Ｒと右の導光光学系２Ｒは、左の対物レンズ群１Ｌと右の導光光学系２Ｌと同一構成のものであり、右の対物レンズ群１Ｒと右の導光光学系２Ｒは、結像レンズ群３の光軸１１_３ を中心に相互に１８０°の回転対称の位置に配置されるものであり、同一の撮像素子４の撮像面の上半分に右の視差像が結像されることになる。
【０１２７】
図８は、撮像素子４の撮像面に投影される左の視差像１２Ｌと右の視差像１２Ｒの位置関係を示す図であり、撮像素子４の撮像面は長辺方向と短辺方向を持つ矩形形状をしており、その長辺方向は左右の視差像１２Ｌ、１２Ｒの回転に合わせてｚ軸正方向に向いて右回りに１３．１°回転して配置される。そして、右の視差像１２Ｒと左の視差像１２Ｌは、矩形の撮像素子４の撮像面の走査方向である長辺方向に略直交する短辺方向に並んで投影される。この際、左の光学系に入射する主光線１０Ｌは、この像面のｘ＝０．１９ｍｍ、ｙ＝−０．８２ｍｍの位置に入射する。右の光学系に入射する主光線１０Ｒは、それと対称なｘ＝−０．１９ｍｍ、ｙ＝０．８２ｍｍの位置に入射する。なお、ここで用いた座標系は先に撮像素子４の像面（撮像面）中心に定義した座標系である。
【０１２８】
以上の説明から明らかなように、本実施例のステレオ撮像光学系は、左右の同一構成の対物レンズ群１Ｌ、１Ｒを視差方向へずらして配置し、それら対物レンズ群１Ｌ、１Ｒから入射した光束を、それぞれ２枚の反射面２１Ｌと２２Ｌ、２１Ｒと２２Ｒからなる左右の同一の導光光学系２Ｌ、２Ｒにより、共通の結像レンズ群３の入射瞳位置へ導き、結像レンズ群３の入射瞳のそれぞれ下半分と上半分を通って結像レンズ群３の像面の下半分と上半分に左右の視差像を投影するようにしたものであり、しかも、対物レンズ群１Ｌと結像レンズ群３、対物レンズ群１Ｒと結像レンズ群３は、それぞれ同じ同軸光学系を構成するように対物レンズ群１Ｌ、１Ｒを配置するため、等価的には１つの対物レンズ群の上側所定画角範囲の光束で左の視差像を、下側所定画角範囲の光束で右の視差像を同じ像面に分けて投影させるようにするために、それら上側所定画角範囲と下側所定画角範囲が被写体の同じ画角範囲をカバーできるように、左右の対物レンズ群１Ｌ、１Ｒのへ入射する主光線１０Ｌ、１０Ｒは相互に平行か被写体までの距離に応じた微小な内輳角を形成するようにする。そのため、左右の対物レンズ群１Ｌ、１Ｒの光軸１１_１Ｌ、１１_１Ｒは平行ではなく、結像レンズ群３の光軸１１_３ を中心に相互にねじれの関係になるように、途中の複数の反射面からなる導光光学系２Ｌ、２Ｒで光路を導くように構成したものである。したがって、左右の対物レンズ群１Ｌ、１Ｒの光軸１１_１Ｌ、１１_１Ｒ相互の角度差は、入射主光線１０Ｌ、１０Ｒ相互の角度差に比較して大きくなる。入射主光線１０Ｌ、１０Ｒ相互は、上記のように平行か被写体までの距離に応じた微小な内輳角を形成しているが、左の対物レンズ群１Ｌの光軸１１_１Ｌと右の対物レンズ群１Ｒの光軸１１_１Ｒとは相互に非平行で反対側を向いている。なお、上記実施例の場合、左の対物レンズ群１Ｌの光軸１１_１Ｌと右の対物レンズ群１Ｒの光軸１１_１Ｒとは交差しないが、一方を含む平面に他方を投影したときの角度差は上記の関係にある。
【０１２９】
ところで、撮像素子４の撮像面は、上記のように、左右の視差像１２Ｌ、１２Ｒの回転に合わせて傾けて配置しており、視差像１２Ｌ、１２の視差方向が撮像素子４の走査線に対して概ね平行になるようにすることが望ましい。通常、撮像系で取得された画像は、水平走査によって画像処理系のフレームメモリーに転送され、一旦記憶され、その後の一連の画像処理に利用される。画像処理の一例として、視差像１２Ｌ、１２Ｒ間の視差画像ステレオマッチング処理の対応点探索を考えると、視差像中の対応点は視差方向に存在するため、対応点探索方向は視差方向に行われるのが最も効率が高い。
【０１３０】
上記のようにフレームメモリーに蓄積された画像情報の読み出しは、読み出しアドレスの指定の観点から、蓄積順に順次読み出すのが効率が高く、結局水平走査方向が視差方向であれば、その後の画像処理に最も効率的な撮像が可能となる。
【０１３１】
また、画像処理の高速化のための並列処理を考えた場合にも、水平走査が前提となれば、垂直走査方向に所定量シフトさせた水平走査線上の画像の処理が、結果的に画素読み出しアドレスにオフセットを加えて処理するだけの単純処理になり、効果的な処理が可能となる。
【０１３２】
したがって、本実施例の場合、ＣＣＤ等の撮像素子４の撮像面を傾け、視差方向が走査線に対して概ね平行になるよう設置されているため、フレームメモリーから無駄なアドレッシング処理なしに、高速に画像処理のための画像読み出しが可能となる。
【０１３３】
ところで、図１〜図８の実施例においては、共通の単一の撮像素子４の撮像面は被写体側と反対側を向くように、導光光学系２Ｌ、２Ｒの第１反射面２１Ｌ、２１Ｒと第２反射面２２Ｌ、２２Ｒによって光路折り曲げているが、その撮像素子４の撮像面が被写体側を向くように導光光学系２Ｌ、２Ｒを構成することも可能である。その場合は、例えば図１において、左の第１反射面２１Ｌは、左の対物レンズ群１Ｌから入射した光路を右の対物レンズ群１Ｒ側へ概ね９０°折り曲げ、第２反射面２２Ｌは、その折り曲げられた光路を左の対物レンズ群１Ｌへ入射する光路と略平行な方向であってその入射光路と略同じ方向へ概ね９０°折り曲げて、共通の結像レンズ群３へ入射させ、同様に、右の第１反射面２１Ｒは、右の対物レンズ群１Ｒから入射した光路を左の対物レンズ群１Ｌ側へ概ね９０°折り曲げ、第２反射面２２Ｒは、その折り曲げられた光路を右の対物レンズ群１Ｒへ入射する光路と略平行な方向であってその入射光路と略同じ方向へ概ね９０°折り曲げて、共通の結像レンズ群３へ入射させるようにすればよい。この場合でも、左右の対物レンズ群１Ｌ、１Ｒ、左右の導光光学系２Ｌ、２Ｒは同一構成のものを用い、結像レンズ群３の光軸１１_３ を中心に相互に１８０°の回転対称の関係に配置し、かつ、左右の対物レンズ群１Ｌ、１Ｒの光軸１１_１Ｌ、１１_１Ｒと結像レンズ群３の光軸１１_３ とを一致した１つの光軸とすることができる。
【０１３４】
ところで、図１（ａ）、（ｂ）からも明らかなように、対物レンズ群１Ｌ、１Ｒに入射する光束は視野マスク５Ｌ、５Ｒによって制限される。これら視野マスク５Ｌ、５Ｒの開口形状は、主光線１０Ｌ、１０Ｒを略中心にした半円形あるいは視差方向に長い矩形のものであり、対物レンズ群１Ｌ、１Ｒの光軸１１_１Ｌ、１１_１Ｒから外れた位置にそれら開口が位置するため、対物レンズ群１Ｌ、１Ｒに入射する光束が通る有効領域も光軸１１_１Ｌ、１１_１Ｒに対して偏心しており、対物レンズ群１Ｌ、１Ｒの有効領域以外をトリミングする際には、対物レンズ群１Ｌ、１Ｒの少なくとも何れかのレンズの外形を、光軸１１_１Ｌ、１１_１Ｒに対して主光線１０Ｌ、１０Ｒが入射する側とは反対側において光軸１１_１Ｌ、１１_１Ｒに最も近づく非回転対称な形状にトリミングすることが望ましい。
【０１３５】
次に、図９は、上記の本発明の実施例に係るステレオ撮像装置を適用したステレオ撮像システムの構成を示す図である。なお、このステレオ撮像システムは、車両に搭載された例として説明する。
【０１３６】
すなわち、このステレオ撮像システムは、距離画像入力装置１００と、制御装置１０４、物体認識装置１０５、警告装置１０６、運転装置１０７、表示装置１０８、車速センサ１０９、測距レーダ１１０、照度センサ１１１、外部カメラ１１２、ＧＰＳ（全地球測位システム）１１３、ＶＩＣＳ（渋滞情報取得装置）１１４、及び、外部通信装置１１５から構成されるものである。
【０１３７】
ここで、上記距離画像入力装置１００は、被写体４００を撮影する撮像素子１０２とこの撮像素子１０２の前方に取り付けられるステレオ撮像光学系１０１とを備えたステレオ撮像装置１１６と、被写体４００の距離画像２０５を計測する距離画像処理装置１０３と、から構成される。
【０１３８】
ステレオ撮像装置１１６は、一般のビデオカメラ、デジタルスティルカメラなどと同様に、撮影絞り調整装置（図示せず）と、撮影フォーカス調整装置（図示せず）と、撮影シャッタ速度調整装置（図示せず）と、感度調整装置（図示せず）とを適宜備えている。
【０１３９】
また、ステレオ撮像光学系１０１は、複数のミラー（１０１Ａ、１０１Ｂの対）からなる反射光学系２１１を有する。この反射光学系２１１は、撮像素子１０２の前方の結像レンズ群１０２Ａの前に取り付けられ、対物レンズ群１０１Ｃから入射した異なる視点からの被写体４００の像を撮像素子１０２に結像することができるようになっている。
【０１４０】
このようにしてステレオ撮像装置１１６で撮影された、すなわち、撮像素子１０２で捕らえたステレオ画像２０１は、図９に示すように、距離画像処理装置１０３に供給される。そして、この距離画像処理装置１０３により処理されて三次元距離画像２０５となり、制御装置１０４及び物体認識装置１０５に出力される。
【０１４１】
なお、「距離画像」という用語は、本明細書では、被写体画像のピクセルに距離情報を有する画像を意味している。
【０１４２】
なお、図９中の参照番号２１２は露出制御装置であり、この露出制御装置２１２は、ステレオ撮像装置１１６が備える上記撮影絞り調整装置、撮影フォーカス調整装置、撮影シャッタ、速度調整装置、及び、感度調整装置（何れも図示せず）に接続されている。また、この露出制御装置２１２は、制御装置１０４に接続されており、この制御装置１０４で、撮像素子１０２からの輝度情報により算出された露出値に応じて撮像装置１１６を制御する。
【０１４３】
また、距離画像処理装置１０３には、上述したように、撮像素子１０２で撮像されたステレオ画像２０１が入力される。このステレオ画像２０１は、フレームメモリ２１３に入力され、デジタル画像２０２となる。
【０１４４】
このフレームメモリ２１３の出力は、レクティフィケーション装置２１４に入力される。このレクティフィケーション装置２１４は、距離算出装置２１５に、左画像２０３及び右画像２０４を出力する。距離算出装置２１５は、距離画像出力２１６を通して物体認識装置１０５に、三次元距離画像２０５を出力する。また、制御装置１０４に対しても、二次元画像（ステレオ画像２０１）、距離画像２０５なども出力する。
【０１４５】
なお、距離画像処理装置１０３には、キャリブレーション装置２１７が別途存在し、レクティフィケーション装置２１４に対してはレクティフィケーションパラメータを、距離算出装置２１５に対しては距離算出用パラメータを、物体認識装置１０５に対しては、物体認識用パラメータを出力する。
【０１４６】
物体認識装置１０５は、入力された三次元距離画像２０５を利用して、その中にある物体あるいは物体領域を認識し、その結果である物体データ（図示せず）を出力する。
【０１４７】
なお、距離画像処理装置１０３内の各装置は、計算機上のソフトウェアで実現してもよい。
【０１４８】
制御装置１０４は、画像情報と車両情報を統括する役割を持っており、例えば、距離画像処理装置１０３で処理された結果を表示装置１０８に表示したり、距離画像処理装置１０３で得られた距離情報と車速センサ１０９等の情報とを分析して、警告装置１０６に警告を発生させたり、運転装置１０７を制御して運転者に安全運転を促すことができるようになっている。なお、警告装置１０６は、音声装置や振動装置などからなり、例えば、音声装置はスピーカ等からの音声、振動装置は運転席シートの振動により運転者に警告を発するものである。
【０１４９】
このように、このステレオ撮像装置を用いたシステムによると、本発明に直接関係しないためその詳細説明は省略するが、本実施例に係るステレオ撮像装置１１６及び距離画像入力装置１００から得られた画像情報と各種センサ等から得られた車両情報とを統合することができ、表示装置１０８による画像情報の表示、警告装置１０６による警告、運転装置１０７の制御等により、運転者に安全走行を促すことができる。
【０１５０】
例えば、前方の被写体に近づきすぎたときに注意を促す表示、警告、さらには運転装置１０７（例えばブレーキ）の制御を行うことができる。
【０１５１】
若しくは、道路の分離帯を読み取って自動で運転を制御する等に用いることができる。
【０１５２】
その他に、車外を観察し、前方や後方の走行車両、障害物、白線検知等に用いる他、車内の運転者、搭乗者の顔の位置、向きを検出し、脇見運転や居眠りの検知、エアバック点火時に、大人か子供かや顔の位置方向を判断し、安全にエアバッグを作動させるセンサとして利用することも可能である。
【０１５３】
また、本発明によるステレオ撮像装置は、車載のステレオ撮像システムの他に、ロボット、鉄道、飛行機、船舶、監視カメラ、遠隔会議システム用カメラ等にも応用ができるものである。
【０１５４】
なお、図９のミラー１０１Ａ、１０１Ｂは、それぞれ図１〜８の第１反射面２１Ｌ、２１Ｒ、第２反射面２２Ｌ、２２Ｒに対応し、対物レンズ群１０１Ｃは対物レンズ群１Ｌ、１Ｒに対応し、結像レンズ群１０２Ａは結像レンズ群３に対応し、撮像素子１０２は撮像素子４に対応する。
【０１５５】
以上の本発明のステレオ撮像装置を適用したステレオ撮像システムは次のように構成することができる。
【０１５６】
〔１〕 請求項１から２２の何れか１項記載のステレオ撮像装置と、前記ステレオ撮像装置からの画像を元に、被写体までの距離を算出し距離信号を出力する画像処理装置と、その距離信号に基づいて他の装置を制御する制御装置とを備えたことを特徴とするステレオ撮像システム。
【０１５７】
〔２〕 前記他の装置が表示装置である上記〔１〕記載のステレオ撮像システム。
【０１５８】
〔３〕 前記他の装置が警告装置である上記〔１〕記載のステレオ撮像システム。
【０１５９】
〔４〕 前記他の装置が運転装置である上記〔１〕記載のステレオ撮像システム。
【０１６０】
【発明の効果】
以上の説明から明らかなように、本発明のステレオ撮像装置によると、小型かつ水平方向（視差方向）の画角が大きいステレオ撮像光学系を備えたステレオ撮像装置を提供することができる。また、収差補正をより良好になし得るステレオ撮像光学系を備えたステレオ撮像装置を提供することができる。さらには、撮像素子上における視差を持つ画像の利用効率が良好なステレオ撮像光学系を備えたステレオ撮像装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の１実施例のステレオ撮像装置の概略の構成を示す模式的な斜視図である。
【図２】図１の実施例の左の光学系の例を示す光路展開図である。
【図３】図２の例のレンズ系の縦収差図である。
【図４】図２の例のレンズ系の横収差図である。
【図５】図２の例のステレオ撮像装置の左の光学系のｘ−ｚ面への投影図である。
【図６】図２の例のステレオ撮像装置の左の光学系のｙ−ｚ面への投影図である。
【図７】図２の例のステレオ撮像装置の左の光学系の斜視図である。
【図８】図１の実施例のステレオ撮像装置の撮像素子の撮像面に投影される左の視差像と右の視差像の位置関係を示す図である。
【図９】本発明の実施例に係るステレオ撮像装置を適用したステレオ撮像システムの構成を示す図である。
【符号の説明】
Ｌ_１ …負メニスカスレンズ（第１レンズ）
Ｌ_２ …平凹負レンズ（第２レンズ）
Ｌ_３ …正メニスカスレンズ（第３レンズ）
Ｌ_４ …両凸正レンズ（第４レンズ）
Ｌ_５ …正メニスカスレンズ（第５レンズ）
Ｌ_６ …平凹負レンズ（第６レンズ）
Ｌ_７ …両凸正レンズ（第７レンズ）
１Ｌ、１Ｒ…対物レンズ群
２Ｌ、２Ｒ…導光光学系
３…結像レンズ群
４…撮像素子
５Ｌ、５Ｒ…視野マスク
６、７…回路部品を配置するスペース
１０Ｌ、１０Ｒ…主光線
１１_１Ｌ、１１_１Ｒ…対物レンズ群の光軸（中心軸、回転軸）
１１_３ …結像レンズ群の光軸（中心軸、回転軸）
１１Ｌ…光軸
１２Ｌ、１２Ｒ…視差像
２１Ｌ、２１Ｒ…第１反射面
２２Ｌ、２２Ｒ…第２反射面
１００…距離画像入力装置
１０１…ステレオ撮像光学系
１０１Ａ、１０１Ｂ…ミラー
１０１Ｃ…対物レンズ群
１０２Ａ…結像レンズ群
１０２…撮像素子
１０３…距離画像処理装置
１０４…制御装置
１０５…物体認識装置
１０６…警告装置
１０７…運転装置
１０８…表示装置
１０９…車速センサ
１１０…測距レーダ
１１１…照度センサ
１１２…外部カメラ
１１３…ＧＰＳ（全地球測位システム）
１１４…ＶＩＣＳ（渋滞情報取得装置）
１１５…外部通信装置
１１６…ステレオ撮像装置
２０１…ステレオ画像
２０２…デジタル画像
２０３…左画像
２０４…右画像
２０５…三次元距離画像
２１１…反射光学系
２１２…露出制御装置
２１３…フレームメモリ
２１４…レクティフィケーション装置
２１５…距離算出装置
２１６…距離画像出力
２１７…キャリブレーション装置
４００…被写体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stereo imaging device, and more particularly, to a stereo imaging device capable of capturing a stereo image having a small size and a large angle of view in a horizontal direction.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, cameras are known in which two images with parallax are arranged side by side and photographed at the same time for the same subject. It is common to shoot images side by side. However, in such photographing, if it is attempted to obtain a stereo image that is long in the horizontal direction, the result is that two images that are long in the horizontal direction are arranged in the horizontal direction, and a useless space is generated on the imaging surface. When a single image sensor simultaneously captures these two images and uses them for distance measurement or the like, it becomes difficult to obtain detailed image information.
[0003]
To solve such a problem, Patent Document 1 discloses a stereo imaging optical system that captures a stereo image in a vertical direction of a horizontally long imaging surface.
[0004]
As shown in FIGS. 1 and 2 of Patent Document 1, this optical system divides a film surface into upper and lower portions, and guides an image having left and right parallaxes to upper and lower portions of a film screen by two reflecting surfaces. It is of a configuration.
[0005]
FIG. 7 of Patent Document 1 also discloses a stereo imaging optical system in which a negative lens is arranged on the subject side and a retrofocus type lens configuration is used to reduce the size and wide angle.
[0006]
[Patent Document 1]
JP-A-8-171151
[0007]
[Problems to be solved by the invention]
However, the imaging optical system described in Patent Literature 1 has a configuration in which the image plane is located on the photographer side. Therefore, when the entire optical system is viewed, the depth direction (incident direction) is configured to be large.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of such a problem of the related art, and an object of the present invention is to provide a stereo imaging apparatus including a stereo imaging optical system which is small and has a large angle of view in a horizontal direction (parallax direction). That is.
[0009]
Still another object of the present invention is to provide a stereo image pickup apparatus including a stereo image pickup optical system capable of better correcting aberrations.
[0010]
It is still another object of the present invention to provide a stereo image pickup apparatus including a stereo image pickup optical system having good use efficiency of an image having parallax on an image pickup device.
[0011]
[Means for Solving the Problems]
A first stereo imaging apparatus according to the present invention that achieves the above object includes a single imaging device and a stereo imaging optical system that forms at least two parallax images having parallax on the single imaging device. A stereo imaging device,
The stereo imaging optical system includes a first objective lens group and a second objective lens group having a negative refractive power and arranged at intervals.
An imaging lens group having a positive refractive power and disposed in an optical path closer to the image sensor than the first objective lens group and the second objective lens group;
A 1-1 reflecting surface for reflecting the light beam incident on the first objective lens group toward the second objective lens group, and a 1-2 for reflecting the light beam from the 1-1 reflecting surface toward the image sensor. A reflective surface,
A 2-1 reflecting surface that reflects the light beam incident on the second objective lens group toward the first objective lens group and a 2-2 that reflects the light beam from the 2-1 reflecting surface toward the image sensor. And a reflecting surface,
The 1-2 reflection surface and the 2-2 reflection surface are disposed so as to reflect the respective reflected light beams toward the subject, and the single imaging device includes the 1-2 reflection surface and the second reflection surface. 2-2 It is characterized by being arranged on the side of the light beam reflected by the reflecting surface.
[0012]
Hereinafter, the operation and effect of the first stereo imaging device of the present invention will be described.
[0013]
Prior to the description, in the present invention, the parallax direction refers to the position of a center ray of light incident on the entrance surface of the first objective lens group and the entrance surface of the second objective lens group from the same subject in the stereo imaging optical system. This is a direction connecting the position of the incident central ray and is usually selected in a horizontal direction (left-right direction), but this direction is not limited, and may be either a vertical direction or an oblique direction. In a parallax image on an image sensor (imaging plane), a relative displacement direction of the same subject in a plurality of parallax images is a parallax direction.
[0014]
Further, in the present invention, a single image sensor is not limited to one having a single light receiving surface (imaging surface), but includes a plurality of light receiving surfaces on the same substrate (substrate; usually a semiconductor substrate). Also means that it is attached.
[0015]
Now, in the stereo imaging optical system of the stereo imaging apparatus of the present invention, a negative objective lens group (first and second lens groups) arranged side by side (hereinafter, the parallax direction means unless otherwise specified). The luminous flux incident from the subject on the objective lens group) is reflected on the respective reflective surfaces (the first objective lens group, the 1-1 reflective surface and the 1-2 reflective surface, and the second objective lens). The group is reflected by the (2-1 reflection surface and the 2-2 reflection surface), and an image having parallax (parallax image) is guided to the image sensor via the imaging lens group. .
[0016]
At this time, the image sensor can be used as a common member, the number of components can be reduced, and the device can be reduced in size and weight.
[0017]
Further, when two image sensors are provided separately for the left and right parallax images, it is not easy to correct the variation in the characteristics of the left and right image sensors and to synchronize the reading of the left and right image sensors. These problems can also be solved by using a single imaging device.
[0018]
Also, since the objective lens group has a negative refractive power and the imaging lens group on the image plane side has a positive refractive power, each of the left and right optical systems can be configured as a retrofocus type, Wide angle of view can be achieved.
[0019]
By the way, if the left and right directions are reduced to further reduce the size of the stereo imaging optical system, an appropriate parallax cannot be obtained, and it is difficult to obtain an effective stereo image. In order to suppress the stereo imaging optical system from being enlarged in the depth direction and the height direction, in the present invention, the optical path is bent as described above, so that the imaging element is disposed between the left and right objective lens groups. I have.
[0020]
As a result, compared to the conventional configuration in which the optical path is bent in the direction in which the depth direction and the height direction increase, the image sensor is arranged in the dead space between the left and right objective lens groups, thereby further miniaturizing the optical system. Can be achieved.
[0021]
According to a second stereo imaging device of the present invention, in the first stereo imaging device, the imaging lens group is disposed immediately before the single imaging device.
[0022]
The operation and effect of the second stereo imaging device will be described.
[0023]
By arranging the imaging optical system in front of the imaging device in this way, it is not necessary to increase the diameter of the imaging optical system as compared with the case where the imaging optical system is arranged only between two reflection surfaces, It is easy to secure telecentricity for the image sensor.
[0024]
According to a third stereo imaging device of the present invention, in the second stereo imaging device, the imaging lens group receives a light beam forming the at least two parallax images and has only one optical axis. It is characterized by the following.
[0025]
The operation and effect of the third stereo imaging device will be described.
[0026]
In addition to the imaging element, the lens group behind the reflecting surface can be used as a common member, and the number of components can be further reduced.
[0027]
A fourth stereo imaging device according to the present invention is the stereoscopic imaging device according to any one of the first to third stereo imaging devices, wherein the 1-1-reflecting surface, the 1-2-reflecting surface, the 2-1-reflecting surface, and the 2- The two reflecting surfaces are arranged such that the parallel arrangement direction of each parallax image projected on the single image sensor is different from the parallel arrangement direction of the first objective lens group and the second objective lens group. Are provided.
[0028]
The operation and effect of the fourth stereo imaging device will be described.
[0029]
By configuring each of the reflecting surfaces in this way, the light beams incident on the left and right objective lens groups are imaged in parallel in a substantially vertical direction of the image sensor through the respective reflecting surfaces. Therefore, when the image sensor is arranged in accordance with the image forming position, it is possible to obtain an image having a wide angle of view in the left-right direction.
[0030]
According to a fifth stereo imaging device of the present invention, in the fourth stereo imaging device, the optical axis of the imaging lens group in the reverse ray tracing of the imaging lens group is equal to the 1-2 reflection surface and the 1-1 reflection surface, and The optical axis when configured to pass through one objective lens group is a first virtual optical axis, and the optical axis of the imaging lens group in reverse ray tracing is the 2-2 reflection surface and the 2-1 reflection surface. And the second virtual optical axis when the optical axis is configured to pass through the first objective lens group, the first virtual optical axis incident on the first objective lens group and the second objective lens group The incident second virtual optical axes are not parallel to each other and are not located in the same plane.
[0031]
The operation and effect of the fifth stereo imaging device will be described.
[0032]
When the imaging lens group is configured to pass through a plurality of left and right reflecting surfaces and the objective lens group when the imaging lens group is used as a common optical system for the left and right rays, the left and right parallax images are formed. In order to avoid this, the light is vignetted by the first and second reflecting surfaces, ie, the first and second reflecting surfaces, which are the optical members closest to the image forming lens group. In order to prevent the occurrence of such vignetting, the first and second reflecting surfaces, the second and second reflecting surfaces, and the objective when the first and second reflecting surfaces are enlarged. Each optical axis passing through the lens group is defined as a virtual optical axis.
[0033]
By setting the virtual optical axes to be non-parallel to each other and not positioned on the same plane, light beams from a common subject are guided so as not to be superimposed on a common image sensor via an imaging lens group. Is possible, and the displacement of the visual field between the parallax images can be prevented. Further, the distance range from the stereo image pickup device where the common subject is arranged can be widened.
[0034]
A sixth stereo imaging apparatus according to the present invention is the fourth stereo imaging apparatus, wherein the first objective lens group and the second objective lens group each include a lens system having a rotationally symmetric optical axis. Are substantially coincident with the optical axis of the imaging lens group when the optical path is expanded, and the optical axis of the first objective lens group and the optical axis of the second objective lens group are non-parallel to each other. , And are not located in the same plane.
[0035]
The operation and effect of the sixth stereo imaging device will be described.
[0036]
If the deviation of the optical axis between the objective lens group and the imaging lens group is large in the state where the optical path is expanded, if the aberration correction is not performed for both the objective lens group and the imaging lens group, the optical axis of both Eccentric aberration is likely to occur due to the deviation.
[0037]
On the other hand, as in the present invention, when the optical axis of the objective lens group and the imaging lens group is made substantially common in a state where the optical path is expanded, residual aberration symmetrical to the optical axis of the imaging lens group is substantially reduced. Since the correction can be performed by the coaxial objective lens group, the influence of the optical axis shift can be reduced.
[0038]
However, when the optical axis of the objective lens group is substantially coincident with the optical axis of the imaging lens group in this way, simply bending the optical axis on the same plane causes the left and right incident light beams to overlap on the subject side. And stereo photography in which a plurality of parallax images having parallax are photographed cannot be performed.
[0039]
Therefore, as described above, by making the optical axes of both objective lens groups non-parallel and not located in the same plane, the left and right parallax images having parallax mutually due to the light flux from the common subject. It can be guided separately on the image sensor.
[0040]
A seventh stereo imaging device of the present invention is the fifth stereo imaging device, wherein the first objective lens group, the 1-1 reflection surface, the 1-2 reflection surface, and the imaging lens group The central ray of the light flux reaching the center of the parallax image projected on a single image sensor is a first principal ray, the second objective lens group, the 2-1 reflecting surface, the 2-2 reflecting surface, and When a central ray of a light flux reaching the center of the parallax image projected onto the single imaging device via the imaging lens group is a second principal ray, the first principal ray incident on the first objective lens group And the second principal ray incident on the second objective lens group is different from the first virtual optical axis incident on the first objective lens group and the second virtual ray incident on the second objective lens group. It is characterized in that it is smaller than the angle difference with the optical axis.
[0041]
An eighth stereo imaging device according to the present invention, in the sixth stereo imaging device, wherein the first objective lens group, the 1-1 reflecting surface, the 1-2 reflecting surface, and the imaging lens group are passed through the first and second reflecting surfaces. The central ray of the light flux reaching the center of the parallax image projected on a single image sensor is a first principal ray, the second objective lens group, the 2-1 reflecting surface, the 2-2 reflecting surface, and When a central ray of a light flux reaching the center of the parallax image projected onto the single imaging device via the imaging lens group is a second principal ray, the first principal ray incident on the first objective lens group And the second principal ray incident on the second objective lens group has an angle difference smaller than the angle difference between the optical axis of the first objective lens group and the optical axis of the second objective lens group. It is assumed that.
[0042]
The operation and effect of the seventh and eighth stereo imaging devices will be described.
[0043]
When these angle differences satisfy the above relation, corresponding points exist in the left and right parallax images, and can be used for, for example, distance measurement of a subject.
[0044]
According to a ninth stereo imaging device of the present invention, in the fourth to eighth stereo imaging devices, the imaging surface of the single imaging element has a rectangular shape having a long side direction and a short side direction. A long-side direction is inclined with respect to a parallax direction of the stereo imaging optical system.
[0045]
According to a tenth stereo imaging device of the present invention, in the fourth to ninth stereo imaging devices, the different direction is a direction substantially orthogonal to a parallax direction of the parallax image. .
[0046]
The operation and effect of the ninth and tenth stereoscopic imaging devices will be described.
[0047]
As in the present invention, in the case of an optical system in which the incident principal rays reaching each parallax image when the optical path is developed are mutually inclined, the optical path is set so that the two principal rays come closer to parallel while bringing the parallax images closer to each other. Is bent, at least one of the first reflection surface (1-1 reflection surface, 2-1 reflection surface) and the second reflection surface (1-2 reflection surface, 2-2 reflection surface) Since the normal must be inclined with respect to a plane including the parallax direction of the stereo imaging optical system, the image plane is inclined with respect to the parallax direction of the stereo imaging optical system.
[0048]
Therefore, by inclining the imaging surface of the imaging device along the inclined image plane, it is possible to effectively use the imaging area. In particular, by setting the direction in which the left and right parallax images are arranged to be substantially perpendicular to the parallax direction of the parallax image, the imaging region can be used most effectively.
[0049]
According to an eleventh stereo imaging device of the present invention, in the first to tenth stereo imaging devices, the imaging surface of the single imaging device has a rectangular shape having a long side direction and a short side direction; Disposing the single imaging element such that a parallax image via a lens group and a parallax image via the second objective lens group are projected side by side in a short side direction of the single imaging element. It is a feature.
[0050]
The operation and effect of the eleventh stereo imaging device will be described.
[0051]
Since the left and right parallax images are projected side by side in the short side direction of the rectangular image sensor, a more horizontally long parallax image can be obtained. This makes it possible to provide a stereo imaging device suitable for a vehicle-mounted stereo imaging device that requires information of a wide angle of view in a substantially horizontal direction.
[0052]
According to a twelfth stereo imaging device of the present invention, in the first to eleventh stereo imaging devices, a scanning direction of the single imaging device is inclined with respect to a parallax direction of the stereo imaging optical system. Things.
[0053]
According to a thirteenth stereo imaging device of the present invention, in the first to twelfth stereo imaging devices, a scanning direction of the single imaging element is substantially parallel to a parallax direction of a parallax image. .
[0054]
The function and effect of the twelfth and thirteenth stereo imaging devices will be described.
[0055]
As in the present invention, in the case of an optical system in which the incident principal rays reaching each parallax image when the optical path is developed are mutually inclined, the optical path is set so that the two principal rays come closer to parallel while bringing the parallax images closer to each other. Is bent, at least one of the first reflection surface (1-1 reflection surface, 2-1 reflection surface) and the second reflection surface (1-2 reflection surface, 2-2 reflection surface) Since the normal must be inclined with respect to a plane including the parallax direction of the stereo imaging optical system, the image plane is inclined with respect to the parallax direction of the stereo imaging optical system. Therefore, by inclining the scanning direction of the image sensor along the inclined image plane, it is possible to shorten the image processing time.
[0056]
According to a fourteenth stereo imaging device of the present invention, in the first to thirteenth stereo imaging devices, the parallax image via the first objective lens group and the parallax image via the second objective lens group are the single unit. Wherein the single imaging element is arranged so as to be projected side by side in a direction substantially perpendicular to the scanning direction of the imaging element.
[0057]
The operation and effect of the fourteenth stereo imaging device will be described.
[0058]
In the case where the image pickup device uses an image receiving surface that is vertically divided and can be read simultaneously, simultaneous parallel processing becomes possible without using a memory, and the image information processing time can be reduced.
[0059]
According to a fifteenth stereo imaging device of the present invention, in the first to fourteenth stereo imaging devices, the focal lengths of the first objective lens group and the second objective lens group are each set to f. _T1 , F _T2 , The focal length of the imaging lens group is f _K , The focal length of the entire system including the first objective lens group is f ₁ , The focal length of the entire system including the second objective lens group is f ₂ , The following conditional expressions (1), (2), (3), and (4) are satisfied.
[0060]
-10.0 <f _T1 / F ₁ <-2.0 (1)
-10.0 <f _T2 / F ₂ <-2.0 (2)
1.5 <f _K / F ₁ <10 ... (3)
1.5 <f _K / F ₂ <10 ... (4)
The operation and effect of the fifteenth stereo imaging device will be described.
[0061]
These conditional expressions define the focal length of each objective lens group and the focal length of the imaging lens group by the focal length of the entire system in order to obtain an image with a short focal length and an appropriate parallax by the entire system. Things. If the lower limit of conditional expressions (1) and (2) exceeds -10.0 and the refractive power of the objective lens group becomes weak, a wide angle of view cannot be obtained, and the diameter of the objective lens group becomes large.
[0062]
On the other hand, when the value exceeds the upper limit of -2.0 of the conditional expressions (1) and (2), the interval between both lens groups becomes short, and it is difficult to arrange and bend a plurality of mirrors between both lens groups. It is becoming.
[0063]
Similarly, when the refractive power of the imaging lens group is increased beyond the lower limit of 1.5 of the conditional expressions (3) and (4), the distance between the two lens groups is shortened, and the imaging exceeds the upper limit of 10 to form a lens. When the refractive power of the image lens group becomes small, the distance between the two lens groups becomes too long, and the device becomes large.
[0064]
Furthermore, the lower limit of conditional expressions (1) and (2) may be set to -8.0. Furthermore, the lower limit of conditional expressions (1) and (2) may be set to -6.0.
[0065]
Further, the upper limit of conditional expressions (1) and (2) may be set to −3.0. Further, the upper limit of conditional expressions (1) and (2) may be set to -4.0.
[0066]
Further, the lower limit of conditional expressions (3) and (4) may be set to 2.5. Furthermore, the lower limit of conditional expressions (3) and (4) may be set to 3.0.
[0067]
Furthermore, the upper limit of conditional expressions (3) and (4) may be set to 7.0. Further, the upper limit of conditional expressions (3) and (4) may be set to 5.0.
[0068]
According to a sixteenth stereo imaging device of the present invention, in the first to fifteenth stereo imaging devices, the lateral magnification of the imaging lens group is β _K Satisfies the following conditional expression (5).
[0069]
−0.4 <β _K <−0.06 (5)
The operation and effect of the sixteenth stereo imaging device will be described.
[0070]
This conditional expression (5) defines the lateral magnification of the imaging lens unit. If the lower limit of -0.4 to condition (5) is not reached, the back focus becomes longer and the entire optical system becomes larger. On the other hand, when the value exceeds the upper limit of -0.06 in the conditional expression (5), the refractive power of the objective lens group becomes weak, so that a wide angle of view cannot be achieved and the diameter of the objective lens group becomes too large.
[0071]
Further, the lower limit of conditional expression (5) may be set to -0.3. Further, the lower limit of conditional expression (5) may be set to -0.25.
[0072]
Further, the upper limit of conditional expression (5) may be set to -0.1. Further, the upper limit of conditional expression (5) may be set to -0.15.
[0073]
With respect to the above conditional expressions (1) to (5), the values of the stereo imaging optical system of the later-described embodiment are as follows.
[0074]
f _T1 = -22.908
f _T2 = -22.908
f _K = 18.714
f ₁ = 5.00
f ₂ = 5.00
f _T1 / F ₁ = -4.57
f _T2 / F ₂ = -4.57
f _K / F ₁ = 3.74
f _K / F ₂ = 3.74
β _K = -0.218
A seventeenth stereo imaging device according to the present invention is the diaphragm member according to any one of the first to sixteenth stereo imaging devices, wherein an aperture pupil is formed between the first objective lens group, the second objective lens group, and the imaging lens group. Is located.
[0075]
The function and effect of the seventeenth stereo imaging device will be described.
[0076]
This makes it easier for the light beam incident on the image sensor to be telecentric. In addition, enlargement of the diameters of the objective lens group and the imaging lens group can be suppressed.
[0077]
An eighteenth stereo imaging device according to the present invention is the seventeenth stereo imaging device, wherein the distance from the aperture member to the entrance surface of the imaging lens group is D when the optical path is expanded. _PK , The focal length of the imaging lens group is f _K Satisfies the following conditional expression (6).
[0078]
0.03 <D _PK / F _K <1.5 ... (6)
The operation and effect of the eighteenth stereo imaging device will be described.
[0079]
Exceeding the lower limit of 0.03 to condition (6) will reduce the effect of making the image sensor telecentric. On the other hand, when the value exceeds the upper limit of 1.5, vignetting of off-axis light flux by the imaging lens group is likely to occur.
[0080]
Further, the lower limit of conditional expression (6) may be set to 0.1. Further, the lower limit of conditional expression (6) may be set to 0.2.
[0081]
Further, the upper limit of conditional expression (6) may be set to 1.0. Further, the upper limit of conditional expression (6) may be set to 0.5.
[0082]
Regarding the above conditional expression (6), the values of the stereo imaging optical system of the later-described embodiment are as follows.
[0083]
D _PK = 8.24
f _K = 18.714
D _PK / F _K = 0.440
According to a nineteenth stereo imaging device of the present invention, in the first to eighteenth stereo imaging devices, a visual field limiting member that separates and forms the at least two parallax images on an imaging surface of the imaging device is provided. It is characterized by having.
[0084]
The function and effect of the nineteenth stereo imaging device will be described.
[0085]
It is preferable to arrange the view restriction members at any positions in the left and right optical paths so that the left and right parallax images do not overlap on the imaging surface. In this case, if there is no intermediate image forming position in the left and right optical paths, the visual field is limited by vignetting.
[0086]
According to a twentieth stereo imaging device of the present invention, in the nineteenth stereo imaging device, at least one of the field limiting members is arranged on a subject side of the objective lens group, and has a substantially rectangular opening. It is characterized by being.
[0087]
The operation and effect of the twentieth stereo imaging device will be described.
[0088]
By disposing the field mask at a position near the subject in the objective lens group, the mask can be easily provided with a field stop function. In addition, by forming the shape close to the desired image shape (substantially rectangular), the function of the field stop and the function of the hood can be fulfilled at the same time.
[0089]
According to a twenty-first stereo imaging device of the present invention, in the twentieth stereo imaging device, the field mask is disposed at a position deviated from the optical axis of the objective lens group.
[0090]
The function and effect of the twenty-first stereo imaging device will be described.
[0091]
When it is desired to form a parallax image in a desired area of the imaging device, it is preferable to dispose the field mask at a position deviated from the objective lens group regardless of the inclination of the objective lens group.
[0092]
According to a twenty-second stereo imaging device of the present invention, in the first to twenty-first stereo imaging devices, the first objective lens group, the 1-1 reflection surface, the 1-2 reflection surface, and the imaging lens group are included. The central ray of the light beam that reaches the center of the parallax image projected on the single image sensor via the first principal ray, the second objective lens group, the 2-1 reflection surface, and the 2-2 reflection surface The first objective lens group and the second objective lens when a central ray of a light flux reaching the center of the parallax image projected onto the single imaging device via the imaging lens group and the second principal ray The outer shape of at least one of the lenses in the group has a non-rotationally symmetrical shape that is closest to the optical axis on the side opposite to the side on which the respective principal rays are incident with respect to the optical axis of the lens. Is what you do.
[0093]
The function and effect of the twenty-second stereo imaging device will be described.
[0094]
It is preferable to remove portions other than the effective surface in the objective lens group. In particular, when the objective lens group is decentered with respect to the principal ray, a part of the region on the opposite side to the principal ray becomes unnecessary, so that the above-described shape can reduce the weight. Furthermore, it is also possible to make such a lens shape to function as a part of the field limiting member.
[0095]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a stereo imaging device of the present invention will be described based on embodiments.
[0096]
FIG. 1 is a schematic perspective view showing a schematic configuration of a stereoscopic imaging apparatus according to one embodiment of the present invention. FIGS. 1A and 1B differ only in the shape of field masks 5L and 5R. Since other configurations are the same, no distinction is made below except for special cases.
[0097]
In the following description, “L” and “R” after a symbol are used to distinguish components and the like belonging to left and right optical paths, unless otherwise specified.
[0098]
This stereo image pickup apparatus includes, for left and right optical paths, left and right objective lens groups 1L and 1R, and first reflection surfaces 21L and 21R and a second reflection surface for sequentially reflecting light incident from the objective lens groups 1L and 1R. 22L and 22R, a common imaging lens group 3 on which the light reflected by the left and right second reflection surfaces 22L and 22R is incident, and a common single imaging arranged on the image plane of the imaging lens group 3 And element 4.
[0099]
As can be seen from the drawing, the reflection directions of the first reflection surfaces 21L and 21R and the second reflection surfaces 22L and 22R are such that the left first reflection surface 21L reflects the light path incident from the left objective lens group 1L on the right objective lens. The second reflecting surface 22L is bent by approximately 90 ° toward the lens group 1R, and the bent optical path is bent by approximately 90 ° in the direction substantially parallel to the optical path incident on the left objective lens group 1L and in the opposite direction. Similarly, the right first reflecting surface 21R bends the optical path incident from the right objective lens group 1R by approximately 90 ° to the left objective lens group 1L side, The reflecting surface 22R bends the bent optical path in a direction substantially parallel to the optical path incident on the right objective lens group 1R and in a direction opposite to the direction by approximately 90 °, so that the light enters the common imaging lens group 3. It has become.
[0100]
For this purpose, in this stereo image pickup apparatus, a common imaging lens group 3 and image pickup device 4 can be arranged between the left and right objective lens groups 1L and 1R, and the width in the left and right direction is set to the left and right objective lens groups 1L and 1R. (The distance obtained by adding the aperture of one objective lens group to the base line length), and the thickness in the depth direction with respect to the subject is determined by the tip surfaces of the objective lens groups 1L and 1R and the first reflecting surface. The distance between the light guide optical system 2L and the rear end surface of the light guide optical system 2L, 2R comprising the second reflection surfaces 22L and 22R is determined by the distance between the light guide optical systems 2L and 2R. Since the area other than the effective area of the groups 1L and 1R can be trimmed, the diameter is substantially equal to or less than the aperture.) Therefore, the size can be reduced.
[0101]
Then, the left parallax image of the binocular parallax image which enters from the left objective lens group 1L, passes through the first reflection surface 21L and the second reflection surface 22L in order, and is formed on the imaging device 4 by the imaging lens group 3 Is inverted and projected on the lower half of the rectangular imaging surface of the imaging device 4, enters from the right objective lens group 1R, passes through the first reflection surface 21R and the second reflection surface 22R in that order, and is formed by the imaging lens group 3. The parallax image on the right side of the binocular parallax image formed on the imaging element 4 is inverted and projected on the upper half of the rectangular imaging surface of the imaging element 4.
[0102]
Here, the parallax direction of the entire optical system of the stereo imaging device is such that when the left and right principal rays are 10L and 10R, the left and right principal rays are incident on the incident lens surfaces of the left and right objective lens groups 1L and 1R or the field masks 5L and 5R. The parallax direction of the parallax image projected on the image sensor 4 is a direction of a straight line B- parallel to a rectangular side of the image sensor 4, which is a direction of a straight line AA 'connecting the points where the light rays 10L and 10R are incident. As is apparent from FIG. 1, in the stereoscopic imaging apparatus of this embodiment, the parallax direction AA ′ of the entire optical system and the parallax direction B of the parallax image projected on the image sensor 4 are shown in FIG. The parallax direction BB ′ is not parallel to −B ′ and is inclined with respect to the parallax direction AA ′. This is because the inclination of the first reflection surfaces 21L and 21R and the inclination of the second reflection surfaces 22L and 22R are not simply inclinations about axes perpendicular to the same plane but inclinations about two axes. This is because rotation of the subject image projected on the element 4 occurs. Here, the left and right principal rays 10L and 10R enter from the objective lens groups 1L and 1R, respectively, pass through the first reflecting surfaces 21L and 21R, and the second reflecting surfaces 22L and 22R in order, and form the imaging element 4 in the imaging lens group 3. It is defined by the center ray of the light flux reaching the center of each of the left and right parallax images formed above.
[0103]
Before the detailed description of the optical system of this embodiment, it is briefly described that the left and right principal rays 10L and 10R are defined as above, whereas the left and right objective lens groups 1L and 1R Are optical axes (center axis, rotation axis) 11 _1L , 11 _1R And the imaging lens group 3 has one optical axis (center axis, rotation axis) 11 ₃ have. Then, when the optical paths of the first reflection surfaces 21L and 21R and the second reflection surfaces 22L and 22R are developed to make each of the left and right optical systems (lens systems) one lens system, the light of the left objective lens group 1L is used. Axis 11 _1L And the optical axis 11 of the imaging lens group 3 ₃ Correspond to one optical axis. Also, the optical axis 11 of the right objective lens group 1R _1R And the optical axis 11 of the imaging lens group 3 ₃ Correspond to one optical axis. The left and right luminous fluxes from the same subject are incident on the left and right objective lens groups 1L and 1R along the left and right principal rays 10L and 10R, respectively, and are respectively placed on the lower half and the upper half of the rectangular imaging surface of the imaging device 4. The left and right parallax images are inverted to form an image.
[0104]
Here, in this embodiment, the principal rays 10L and 10R incident on the left and right objective lens groups 1L and 1R are _1L , 11 _1R Does not coincide with the left optical axis 11L. _1L And the right incident chief ray 10R is directed to the right optical axis 11 _1R Angled below. However, in order to form the left and right parallax images, the principal rays 10L and 10R incident on the left and right objective lens groups 1L and 1R are parallel to each other or have an inner convergence angle corresponding to the distance to the subject in substantially the same plane. The optical axes 11 of the left and right objective lens groups 1L, 1R _1L , 11 _1R Is the optical axis 11 of the imaging lens group 3 ₃ Are in a torsional relationship with each other, and are in a 180 ° rotationally symmetric relationship.
[0105]
Field masks 5L and 5R for passing an image forming light beam centered on the principal rays 10L and 10R and restricting unnecessary light are arranged on the incident sides of the left and right objective lens groups 1L and 1R, respectively, as shown in FIG. 1) is an example in which the lower objective lens group 1L is covered with a substantially lower side and the right objective lens group 1R is covered with a substantially upper side, and in the case of FIG. A horizontally long rectangular shape that covers a substantially lower side of the objective lens group 1L and restricts the parallax image formed on the image sensor 4 to a rectangular shape that is long to the left and right, and covers a substantially upper side of the right objective lens group 1R. This is an example in which the parallax image formed on the image 4 is formed in a horizontally long rectangular shape that restricts the parallax image to a rectangular shape that is long in the left and right directions.
[0106]
The first reflecting surfaces 21L and 21R have a size and a shape that do not limit the effective light beam transmitted through the objective lens groups 1L and 1R, and are approximately 45 ° in the horizontal direction and several degrees toward the image sensor 3 in the vertical direction. It is arranged to be inclined, and makes the reflected light flux enter the second reflection surfaces 22L and 22R. The second reflecting surfaces 22L and 22R are arranged substantially vertically to the second reflecting surfaces 22L and 22R in the horizontal direction and at a slight angle toward the image sensor in the vertical direction. Is incident. As shown in FIG. 1, the second reflecting surfaces 22L and 22R are arranged such that, when viewed from the vertical direction, the left second reflecting surface 22L and the right second reflecting surface 22R cross each other. It is arranged to deflect a light beam incident from the left and right in the direction of the imaging lens group 3 so as to be incident from above and below. Here, the second reflecting surfaces 22L and 22R constitute an aperture member forming an exit pupil.
[0107]
The luminous fluxes restricted by the field masks 5L and 5R are transmitted through a low-pass filter (not shown) by the imaging lens group 3, and then form respective parallax images in one of the upper and lower halves of the image sensor 4. . Due to the action of the field masks 5L and 5R, the upper and lower parallax images are separated and formed on the image sensor 4 without overlapping each other.
[0108]
Here, it is important that the left and right objective lens groups 1L and 1R and the left and right light guide optical systems 2L and 2R are the same, and the optical axis 11 of the imaging lens group 3 is used. ₃ Are arranged in a rotationally symmetric relationship with respect to each other at 180 °, so that the same pair of components may be arranged at positions mutually rotated by 180 ° to the left and right.
[0109]
Since the objective lens groups 1L and 1R have a negative refractive power and the imaging lens group 3 has a positive refractive power, the left and right optical systems each have a retrofocus type configuration, and have a wide angle of view. Left and right parallax images can be captured.
[0110]
In FIG. 1, reference numerals 6 and 7 denote upper and lower spaces in which circuit components of the stereo imaging device are arranged.
[0111]
Next, details of the stereo imaging optical system of the stereo imaging device of the present embodiment will be described.
[0112]
As described above, the left and right objective lens groups 1L and 1R and the left and right light guide optical systems 2L and 2R have the same configuration. ₃ Are arranged in a 180 ° rotationally symmetric relationship with each other. Then, the optical axes 11 of the left and right objective lens groups 1L, 1R _1L And the optical axis 11 of the imaging lens group 3 ₃ Are the same optical axis, so the left optical system will be mainly described.
[0113]
FIG. 2 is an optical path development diagram showing the left optical system. The left objective lens group 1L, the first reflecting surface 21L, the second reflecting surface 22L, and the imaging lens group 3 are arranged such that the optical axis 11L indicated by a chain line is shown. A rotationally symmetric optical system having a center is formed. In this drawing, the first reflection surface 21L and the second reflection surface 22L are represented by straight lines perpendicular to the optical axis 11L. However, in a state where the optical path is not expanded, the first reflection surface 21L and the second reflection surface 22L are not reflected by this light. As described later, the optical system is not rotationally symmetrical with respect to the arrangement of the optical system because the optical system is inclined around two axes with respect to the axis 11L.
[0114]
As is clear from FIG. 2, the left objective lens group 1L has a negative meniscus lens L having a convex surface facing the object side. ₁ And a plano-concave negative lens L ₂ And a positive meniscus lens L having a convex surface facing the object side ₃ The imaging lens group 3 includes a biconvex positive lens L ₄ And a positive meniscus lens L having a convex surface facing the object side ₅ And a plano-concave negative lens L ₆ And a biconvex positive lens L ₇ , And a stop is disposed at the position of the second reflection surface 22L (the outer shape of the second reflection surface 22L forms a stop). The angle of view (the angle between the optical axis 11L and the principal ray 10L) through which the principal ray 10L reaches the center of the left parallax image formed on the lower half of the imaging plane (image plane) of the imaging element 4 is 9. 7 °.
[0115]
The lens data of this lens system is as shown in Table 1 below. However, in the table, r ₁ , R ₂ ... is the lens L ₁ The radius of curvature of each lens surface (including the reflecting surface and the image surface) in order from the incident side surface of d, d ₁ , D ₂ ... is the distance between the lens surfaces, n _d1 , N _d2 ... is the d-line refractive index of each lens, ν _d1 , Ν _d2 ... is the Abbe number of each lens. In Table 1, the full angle of view of the lens system itself is shown, but the angle of view shown as the left optical system is from 9.7 ° ± 7 ° in the vertical direction (vertical direction) from 2.7 ° to 16 °. In the left-right direction (horizontal direction, parallax direction), it is 42 °.
[0116]
FIG. 3 shows a longitudinal aberration diagram of the lens system of this embodiment, and FIG. 4 shows a lateral aberration diagram thereof. In these aberration diagrams, “SA” indicates spherical aberration, “AS” indicates astigmatism, “DT” indicates distortion, and “CC” indicates lateral chromatic aberration. In each aberration diagram, “ω” indicates an angle of view on one side.
[0117]
Now, the coordinates are defined here. At the center of the image plane (imaging plane) of the imaging element 4, the z-axis, which is a normal direction toward the subject (a direction from the front to the back of the image plane), is orthogonal to the z-axis, An x-axis that is positively directed from the surface in the direction of the objective lens group, a y-axis that is orthogonal to the z-axis and the x-axis and that constitutes a right-handed coordinate system are defined.
[0118]
FIG. 5 is a projection view of the left optical system of the stereo imaging device of the present embodiment on the xz plane, and FIG. 6 is a projection view of the left optical system on the yz plane. As described above, the first reflection surface 21L and the second reflection surface 22L are inclined around two axes, but the rotation (tilt) of the first reflection surface 21L and the second reflection surface 22L is the y-axis. As the rotation angle, the clockwise direction is positive and the counterclockwise direction is negative in the positive y-axis direction of the coordinate system set at the center of the image plane, and the normal of each reflecting surface is in the positive z-axis direction. The position is defined as a rotation angle of 0 °. As the rotation angle around the x-axis, the x-axis of the coordinate system set at the center of the image plane is rotated together with the rotation of each reflection surface, that is, the x-axis is orthogonal to the y-axis in each reflection surface. It is defined that the clockwise direction is defined as positive, and the counterclockwise direction is defined as negative in the positive direction of the newly set x-axis.
[0119]
In this embodiment, as shown in Table 2 below, the rotation angle of the first reflection surface 21L around the y axis is -44.6 °, the rotation angle around the x axis is + 8 °, and the rotation angle of the second reflection surface 22L is + 8 °. The rotation angle around the y axis is + 45 °, and the rotation angle around the x axis is −1.2 °.
[0120]
In addition, the surface top positions of the lens surfaces (including the reflection surface and the image surface) in the coordinate system defined at the center of the image plane (imaging plane) of the imaging element 4 are as shown in Table 3 below.
[0121]
FIG. 7 is a perspective view of the left optical system shown in the optical path development view in FIG. 2 described above, the projection view on the xz plane in FIG. 5, and the projection view on the yz plane in FIG. .
[0122]

[0123]

[0124]

[0125]
In Tables 1 to 3 above, the unit of the value representing the dimension is mm.
[0126]
The left optical system of the stereo imaging optical system of this embodiment has been described above. However, as described above, the right optical system shares the imaging lens group 3 and the right objective lens group 1R and the right guiding lens group. The optical optical system 2R has the same configuration as the left objective lens group 1L and the right light guide optical system 2L, and the right objective lens group 1R and the right light guide optical system 2R Optical axis 11 ₃ Are arranged at positions 180 ° rotationally symmetric with respect to each other, and a right parallax image is formed on the upper half of the imaging surface of the same imaging device 4.
[0127]
FIG. 8 is a diagram showing a positional relationship between the left parallax image 12L and the right parallax image 12R projected on the imaging surface of the imaging device 4, wherein the imaging surface of the imaging device 4 has a long side direction and a short side direction. It has a rectangular shape, and its long side is rotated 13.1 ° clockwise in the positive z-axis direction in accordance with the rotation of the left and right parallax images 12L and 12R. Then, the right parallax image 12R and the left parallax image 12L are projected side by side in a short side direction substantially orthogonal to a long side direction which is a scanning direction of the imaging surface of the rectangular imaging element 4. At this time, the principal ray 10L entering the left optical system enters the image plane at a position of x = 0.19 mm and y = −0.82 mm. The principal ray 10R incident on the right optical system enters at a position symmetrical to x = −0.19 mm and y = 0.82 mm. Note that the coordinate system used here is the coordinate system previously defined at the center of the image plane (imaging plane) of the image sensor 4.
[0128]
As is apparent from the above description, the stereo imaging optical system of the present embodiment arranges the left and right objective lens groups 1L and 1R having the same configuration so as to be displaced in the parallax direction, and the luminous flux incident from the objective lens groups 1L and 1R. Are guided to the entrance pupil position of the common imaging lens group 3 by the same left and right identical light guide optical systems 2L and 2R each composed of two reflection surfaces 21L and 22L, and 21R and 22R. The left and right parallax images are projected onto the lower half and the upper half of the image plane of the imaging lens group 3 through the lower half and the upper half of the entrance pupil, respectively. The lens group 3, the objective lens group 1R, and the imaging lens group 3 have the objective lens groups 1L, 1R arranged so as to form the same coaxial optical system. Left parallax with luminous flux in angular range In order to project the right parallax image on the same image plane with the luminous flux in the lower predetermined angle of view range, the upper predetermined angle of view range and the lower predetermined angle of view range have the same angle of view of the subject. The main rays 10L and 10R incident on the left and right objective lens groups 1L and 1R are formed so as to be parallel to each other or to form a small angle of convergence according to the distance to the subject so as to cover. Therefore, the optical axes 11 of the left and right objective lens groups 1L, 1R _1L , 11 _1R Is not parallel, and the optical axis 11 of the imaging lens group 3 is ₃ The optical path is guided by the light guide optical systems 2L and 2R comprising a plurality of reflection surfaces on the way so that the optical paths are twisted about each other. Therefore, the optical axes 11 of the left and right objective lens groups 1L, 1R _1L , 11 _1R The angle difference between them becomes larger than the angle difference between the incident principal rays 10L and 10R. Although the incident principal rays 10L and 10R are parallel or form a small angle of convergence according to the distance to the subject as described above, the optical axis 11 of the left objective lens group 1L is formed. _1L And the optical axis 11 of the right objective lens group 1R _1R Are non-parallel to each other and facing away from each other. In the case of the above embodiment, the optical axis 11 of the left objective lens group 1L _1L And the optical axis 11 of the right objective lens group 1R _1R Does not intersect, but the angle difference when the other is projected on a plane including one has the above relationship.
[0129]
By the way, as described above, the imaging surface of the imaging element 4 is arranged to be inclined in accordance with the rotation of the left and right parallax images 12L and 12R, and the parallax direction of the parallax images 12L and 12 is aligned with the scanning line of the imaging element 4. It is desirable to make them substantially parallel to each other. Normally, an image obtained by an imaging system is transferred to a frame memory of an image processing system by horizontal scanning, temporarily stored, and used for a series of subsequent image processing. As an example of image processing, considering a corresponding point search of the parallax image stereo matching process between the parallax images 12L and 12R, the corresponding point in the parallax image exists in the parallax direction, and the corresponding point search direction is performed in the parallax direction. Is the most efficient.
[0130]
As described above, in order to read out the image information stored in the frame memory, it is highly efficient to sequentially read out the image data in the order of storage from the viewpoint of specifying the read address. If the horizontal scanning direction is the parallax direction after all, the subsequent image processing is performed. The most efficient imaging becomes possible.
[0131]
Also, in consideration of parallel processing for speeding up image processing, if horizontal scanning is assumed, processing of an image on a horizontal scanning line shifted by a predetermined amount in the vertical scanning direction results in pixel reading. Simple processing is performed simply by adding an offset to an address, and effective processing can be performed.
[0132]
Therefore, in the case of the present embodiment, since the image pickup surface of the image pickup device 4 such as a CCD is tilted and the parallax direction is set substantially parallel to the scanning line, high-speed operation can be performed without unnecessary addressing processing from the frame memory. Thus, image reading for image processing becomes possible.
[0133]
By the way, in the embodiment of FIGS. 1 to 8, the first reflecting surfaces 21L and 21R of the light guide optical systems 2L and 2R such that the imaging surface of the single common imaging device 4 faces the opposite side to the subject side. Although the optical path is bent by the second reflection surfaces 22L and 22R, the light guide optical systems 2L and 2R can be configured so that the imaging surface of the imaging device 4 faces the subject. In that case, for example, in FIG. 1, the left first reflecting surface 21L bends the optical path incident from the left objective lens group 1L toward the right objective lens group 1R by approximately 90 °, and the second reflecting surface 22L is The bent optical path is bent by approximately 90 ° in a direction substantially parallel to the optical path incident on the left objective lens group 1L and substantially in the same direction as the incident optical path, and is incident on the common imaging lens group 3, similarly. The right first reflecting surface 21R bends the optical path incident from the right objective lens group 1R toward the left objective lens group 1L by approximately 90 °, and the second reflecting surface 22R converts the bent optical path into the right objective lens group. What is necessary is just to bend approximately 90 ° in a direction substantially parallel to the optical path incident on the lens group 1R and substantially the same direction as the incident optical path, and to make it be incident on the common imaging lens group 3. Also in this case, the left and right objective lens groups 1L and 1R and the left and right light guide optical systems 2L and 2R have the same configuration, and the optical axis 11 of the imaging lens group 3 is used. ₃ And the optical axes 11 of the left and right objective lens groups 1L, 1R _1L , 11 _1R And the optical axis 11 of the imaging lens group 3 ₃ Can be set as one optical axis that matches.
[0134]
By the way, as is clear from FIGS. 1A and 1B, the light flux incident on the objective lens groups 1L and 1R is restricted by the field masks 5L and 5R. The aperture shape of each of the field masks 5L, 5R is a semicircle centered on the principal rays 10L, 10R or a rectangular shape long in the parallax direction, and the optical axis 11 of the objective lens groups 1L, 1R. _1L , 11 _1R Since the apertures are located at positions deviated from the optical axis, the effective area through which the light beams incident on the objective lens groups 1L and 1R pass also has the optical axis 11 _1L , 11 _1R When trimming other than the effective area of the objective lens groups 1L and 1R, the outer shape of at least one of the objective lens groups 1L and 1R is changed to the optical axis 11 _1L , 11 _1R The optical axis 11 on the side opposite to the side on which the chief rays 10L and 10R enter. _1L , 11 _1R It is desirable to trim to a non-rotationally symmetrical shape that comes closest to
[0135]
Next, FIG. 9 is a diagram showing a configuration of a stereo imaging system to which the stereo imaging device according to the embodiment of the present invention is applied. Note that this stereo imaging system will be described as an example mounted on a vehicle.
[0136]
That is, this stereo imaging system includes a range image input device 100, a control device 104, an object recognition device 105, a warning device 106, a driving device 107, a display device 108, a vehicle speed sensor 109, a ranging radar 110, an illuminance sensor 111, an external It comprises a camera 112, a GPS (Global Positioning System) 113, a VICS (Congestion Information Acquisition Device) 114, and an external communication device 115.
[0137]
Here, the range image input device 100 includes a stereo image pickup device 116 including an image pickup device 102 for photographing a subject 400 and a stereo image pickup optical system 101 mounted in front of the image pickup device 102, and a distance image 205 of the subject 400. And a distance image processing device 103 for measuring the distance.
[0138]
The stereo imaging device 116 includes a shooting aperture adjustment device (not shown), a shooting focus adjustment device (not shown), and a shooting shutter speed adjustment device (not shown), like a general video camera, digital still camera, or the like. ) And a sensitivity adjusting device (not shown) as appropriate.
[0139]
Further, the stereo imaging optical system 101 has a reflection optical system 211 including a plurality of mirrors (a pair of 101A and 101B). The reflection optical system 211 is mounted in front of the imaging lens group 102A in front of the imaging device 102, and can form an image of the subject 400 from a different viewpoint incident from the objective lens group 101C on the imaging device 102. It has become.
[0140]
The stereo image 201 thus captured by the stereo imaging device 116, that is, captured by the image sensor 102, is supplied to the distance image processing device 103 as shown in FIG. Then, the image is processed by the distance image processing device 103 to become a three-dimensional distance image 205, which is output to the control device 104 and the object recognition device 105.
[0141]
Note that the term “distance image” in this specification means an image having distance information in pixels of a subject image.
[0142]
Reference numeral 212 in FIG. 9 denotes an exposure control device. The exposure control device 212 includes the above-described shooting aperture adjustment device, shooting focus adjustment device, shooting shutter, speed adjustment device, and sensitivity provided in the stereo imaging device 116. It is connected to an adjusting device (neither is shown). The exposure control device 212 is connected to the control device 104, and controls the imaging device 116 according to the exposure value calculated based on the luminance information from the imaging device 102.
[0143]
Further, the stereo image 201 captured by the image sensor 102 is input to the distance image processing device 103 as described above. The stereo image 201 is input to the frame memory 213 and becomes a digital image 202.
[0144]
The output of the frame memory 213 is input to the rectification device 214. The rectification device 214 outputs the left image 203 and the right image 204 to the distance calculation device 215. The distance calculation device 215 outputs the three-dimensional distance image 205 to the object recognition device 105 through the distance image output 216. Further, a two-dimensional image (stereo image 201), a distance image 205, and the like are also output to the control device 104.
[0145]
Note that a calibration device 217 is separately provided in the distance image processing device 103, a rectification parameter is provided for the rectification device 214, a distance calculation parameter is provided for the distance calculation device 215, and an object recognition An object recognition parameter is output to the device 105.
[0146]
The object recognizing device 105 recognizes an object or an object region therein using the input three-dimensional distance image 205, and outputs the resulting object data (not shown).
[0147]
Each device in the distance image processing device 103 may be realized by software on a computer.
[0148]
The control device 104 has a role of controlling the image information and the vehicle information. For example, the control device 104 displays a result processed by the distance image processing device 103 on the display device 108, or displays a distance obtained by the distance image processing device 103. By analyzing the information and the information from the vehicle speed sensor 109 and the like, a warning can be issued to the warning device 106 and the driving device 107 can be controlled to prompt the driver to drive safely. The warning device 106 includes a voice device, a vibration device, and the like. For example, the voice device is a voice from a speaker or the like, and the vibration device warns a driver by vibration of a driver's seat.
[0149]
As described above, according to the system using the stereo imaging device, since it is not directly related to the present invention, the detailed description is omitted, but the image obtained from the stereo imaging device 116 and the range image input device 100 according to the present embodiment is omitted. The information can be integrated with vehicle information obtained from various sensors and the like, and the driver is encouraged to drive safely by displaying image information on the display device 108, warning by the warning device 106, controlling the driving device 107, and the like. Can be.
[0150]
For example, it is possible to perform a display, a warning, and a control of the driving device 107 (for example, a brake) for calling attention when the subject is too close to the subject in front.
[0151]
Alternatively, it can be used for reading a road divider and automatically controlling driving.
[0152]
In addition to observing the outside of the vehicle and using it to detect vehicles running ahead and behind, obstacles, white lines, etc., it also detects the position and orientation of the driver's and passenger's faces in the vehicle, detection of inattentive driving and dozing, air At the time of back ignition, it is also possible to determine the position direction of an adult, a child, or a face, and use the sensor as a sensor for activating an airbag safely.
[0153]
Further, the stereo imaging device according to the present invention can be applied to a robot, a railway, an airplane, a ship, a surveillance camera, a camera for a remote conference system, and the like, in addition to a stereo imaging system mounted on a vehicle.
[0154]
The mirrors 101A and 101B in FIG. 9 correspond to the first reflecting surfaces 21L and 21R and the second reflecting surfaces 22L and 22R in FIGS. 1 to 8, respectively. The objective lens group 101C corresponds to the objective lens groups 1L and 1R. , The imaging lens group 102A corresponds to the imaging lens group 3, and the imaging device 102 corresponds to the imaging device 4.
[0155]
A stereo imaging system to which the above-described stereo imaging apparatus of the present invention is applied can be configured as follows.
[0156]
[1] The stereo imaging device according to any one of claims 1 to 22, an image processing device that calculates a distance to a subject based on an image from the stereo imaging device, and outputs a distance signal, and the distance A stereo imaging system comprising: a control device that controls another device based on a signal.
[0157]
[2] The stereo imaging system according to [1], wherein the other device is a display device.
[0158]
[3] The stereo imaging system according to the above [1], wherein the other device is a warning device.
[0159]
[4] The stereo imaging system according to the above [1], wherein the other device is a driving device.
[0160]
【The invention's effect】
As is clear from the above description, according to the stereo imaging apparatus of the present invention, it is possible to provide a stereo imaging apparatus including a stereo imaging optical system that is small and has a large angle of view in the horizontal direction (parallax direction). Further, it is possible to provide a stereo image pickup device including a stereo image pickup optical system capable of better correcting aberration. Further, it is possible to provide a stereo image pickup apparatus provided with a stereo image pickup optical system having good use efficiency of an image having parallax on an image pickup device.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a schematic configuration of a stereo imaging device according to an embodiment of the present invention.
FIG. 2 is an optical path development diagram showing an example of a left optical system in the embodiment of FIG. 1;
FIG. 3 is a longitudinal aberration diagram of the lens system in the example of FIG. 2;
FIG. 4 is a lateral aberration diagram of the lens system in the example of FIG. 2;
FIG. 5 is a projection view of the left optical system of the example of the stereoscopic imaging apparatus in FIG. 2 onto the xz plane.
FIG. 6 is a projection view of the left optical system of the example of the stereoscopic imaging apparatus of FIG. 2 onto the yz plane.
FIG. 7 is a perspective view of a left optical system of the stereo imaging device in the example of FIG. 2;
8 is a diagram illustrating a positional relationship between a left parallax image and a right parallax image projected on an imaging surface of an imaging element of the stereoscopic imaging device of the embodiment in FIG.
FIG. 9 is a diagram illustrating a configuration of a stereo imaging system to which the stereo imaging device according to the embodiment of the present invention is applied.
[Explanation of symbols]
L ₁ … Negative meniscus lens (first lens)
L ₂ … Plano-concave negative lens (second lens)
L ₃ … Positive meniscus lens (third lens)
L ₄ … Biconvex positive lens (4th lens)
L ₅ … Positive meniscus lens (fifth lens)
L ₆ ... plano-concave negative lens (sixth lens)
L ₇ … A biconvex positive lens (seventh lens)
1L, 1R: Objective lens group
2L, 2R ... Light guide optical system
3 ... imaging lens group
4: Image sensor
5L, 5R: Field mask
6, 7 ... space for arranging circuit components
10L, 10R ... chief ray
11 _1L , 11 _1R … The optical axis of the objective lens group (center axis, rotation axis)
11 ₃ … Optical axis (center axis, rotation axis) of the imaging lens group
11L: Optical axis
12L, 12R: Parallax image
21L, 21R: first reflection surface
22L, 22R: second reflecting surface
100 distance image input device
101: Stereo imaging optical system
101A, 101B ... Mirror
101C: Objective lens group
102A: imaging lens group
102: Image sensor
103: Range image processing device
104 ... Control device
105: Object recognition device
106 warning device
107 ... Driving device
108 display device
109 ... Vehicle speed sensor
110 ... Ranging radar
111 ... Illuminance sensor
112 ... External camera
113 ... GPS (Global Positioning System)
114 ... VICS (Congestion information acquisition device)
115 ... External communication device
116: Stereo imaging device
201: Stereo image
202 ... Digital image
203 ... left image
204 ... right image
205: 3D range image
211 ... Reflection optical system
212 ... Exposure control device
213 ... Frame memory
214 ... Rectification device
215—Distance calculation device
216: Distance image output
217: Calibration device
400 subject

Claims (22)

A stereo imaging device comprising a single imaging device and a stereo imaging optical system that forms at least two parallax images having parallax mutually on the single imaging device,
The stereo imaging optical system includes a first objective lens group and a second objective lens group having a negative refractive power and arranged at intervals.
An imaging lens group having a positive refractive power and disposed in an optical path closer to the image sensor than the first objective lens group and the second objective lens group;
A 1-1 reflecting surface for reflecting the light beam incident on the first objective lens group toward the second objective lens group, and a 1-2 for reflecting the light beam from the 1-1 reflecting surface toward the image sensor. A reflective surface,
A 2-1 reflecting surface that reflects the light beam incident on the second objective lens group toward the first objective lens group and a 2-2 that reflects the light beam from the 2-1 reflecting surface toward the image sensor. And a reflecting surface,
The 1-2 reflection surface and the 2-2 reflection surface are disposed so as to reflect the respective reflected light beams toward the subject, and the single imaging device includes the 1-2 reflection surface and the second reflection surface. 2-2 A stereo imaging device, which is disposed on the side of a light beam reflected by a reflection surface. The stereo imaging device according to claim 1, wherein the imaging lens group is disposed immediately before the single imaging device. The stereo imaging device according to claim 2, wherein the imaging lens group receives a light beam that forms the at least two parallax images and has only one optical axis. The 1-1 reflection surface, the 1-2 reflection surface, the 2-1 reflection surface, and the 2-2 reflection surface are arranged in parallel of respective parallax images projected on the single image sensor. 4. The arrangement according to claim 1, wherein the arrangement direction is different from the parallel arrangement direction of the first objective lens group and the second objective lens group. Stereo imaging device. The optical axis in the case where the optical axis of the imaging lens group in the reverse ray tracing is configured to pass through the 1-2 reflective surface, the 1-1 reflective surface, and the first objective lens group is defined as a first virtual. The optical axis, the optical axis in the reverse ray tracing of the imaging lens group, is configured so as to pass through the 2-2 reflection surface, the 2-1 reflection surface, and the second objective lens group. When the second virtual optical axis is set as the second virtual optical axis, the first virtual optical axis incident on the first objective lens group and the second virtual optical axis incident on the second objective lens group are not parallel to each other and are the same. The stereo imaging device according to claim 4, wherein the stereo imaging device is not located in a plane. The first objective lens group and the second objective lens group each include a lens system having an optical axis that is rotationally symmetric, and each optical axis is substantially the same as the optical axis of the imaging lens group when the optical path is expanded. The optical axis of the first objective lens group and the optical axis of the second objective lens group are not parallel to each other, and are not located in the same plane. Stereo imaging device. The center of a light beam that reaches the center of a parallax image projected on the single imaging device via the first objective lens group, the 1-1 reflection surface, the 1-2 reflection surface, and the imaging lens group. A parallax image projected on the single imaging device through a first principal ray, the second objective lens group, the 2-1 reflection surface, the 2-2 reflection surface, and the imaging lens group. Angle difference between the first principal ray incident on the first objective lens group and the second principal ray incident on the second objective lens group, where the central ray of the light beam reaching the center of Is smaller than the angle difference between the first virtual optical axis incident on the first objective lens group and the second virtual optical axis incident on the second objective lens group. 5 is the stereo imaging device described. The center of a light flux reaching the center of a parallax image projected on the single imaging device via the first objective lens group, the 1-1-reflection surface, the 1-2-reflection surface, and the imaging lens group. A parallax image projected on the single imaging device through a first principal ray, the second objective lens group, the 2-1 reflection surface, the 2-2 reflection surface, and the imaging lens group. Angle difference between the first principal ray incident on the first objective lens group and the second principal ray incident on the second objective lens group, where the central ray of the light beam reaching the center of 7. The stereo imaging apparatus according to claim 6, wherein an angle difference between an optical axis of the first objective lens group and an optical axis of the second objective lens group is smaller. The imaging surface of the single imaging device has a rectangular shape having a long side direction and a short side direction, and a long side direction of the imaging surface is inclined with respect to a parallax direction of the stereo imaging optical system. The stereo imaging device according to claim 4. The stereo imaging device according to claim 4, wherein the different direction is a direction substantially orthogonal to a parallax direction of the parallax image. The imaging surface of the single imaging device has a rectangular shape having a long side direction and a short side direction, and a parallax image passing through the first objective lens group and a parallax image passing through the second objective lens group, The stereo imaging device according to any one of claims 1 to 10, wherein the single image sensor is arranged so as to be projected side by side in a short side direction of the single image sensor. The stereo imaging device according to claim 1, wherein a scanning direction of the single imaging device is inclined with respect to a parallax direction of the stereo imaging optical system. The stereo imaging device according to claim 1, wherein a scanning direction of the single imaging element is substantially parallel to a parallax direction of a parallax image. The single parallax image passing through the first objective lens group and the parallax image passing through the second objective lens group are projected side by side in a direction substantially orthogonal to the scanning direction of the single imaging device. 14. The stereo image pickup device according to claim 1, further comprising: an image pickup device. The focal lengths of the first objective lens group and the second objective lens group are f _T1 and f _T2 , respectively, the focal length of the imaging lens group is f _K , and the focal length of the whole system including the first objective lens group is f _T1 . f ₁ , when the focal length of the entire system including the second objective lens group is f ₂ , the following conditional expressions (1), (2), (3), and (4) are satisfied. The stereo imaging device according to any one of claims 1 to 14, wherein:
_{-10.0 <f T1 / f 1 <} -2.0 ··· (1)
_{-10.0 <f T2 / f 2 <} -2.0 ··· (2)
_{1.5 <f K / f 1 <} 10 ··· (3)
_{1.5 <f K / f 2 <} 10 ··· (4) The lateral magnification of the imaging lens when the beta _K, the following conditional expression (5) Stereo imaging apparatus according to any one which satisfies the preceding claims, wherein 15 of the.
−0.4 <β _K <−0.06 (5) 17. The stereo imaging according to claim 1, wherein an aperture member that forms an exit pupil is located between the first objective lens group, the second objective lens group, and the imaging lens group. apparatus. In developed state of the optical path, the diaphragm distance D _PK from member to the entrance surface of the imaging _lens, the focal length of the imaging lens group when the f _K, the following conditional expression (6) The stereo imaging device according to claim 17, wherein the stereo imaging device is satisfied.
0.03 <D _PK / f _K <1.5 (6) The stereo imaging device according to claim 1, further comprising: a field-of-view limiting member configured to separate and form the at least two parallax images on an imaging surface of the imaging device. 20. The stereo imaging apparatus according to claim 19, wherein at least one of the field limiting members is a field mask arranged on the object side of the objective lens group and having a substantially rectangular opening. 21. The stereo imaging apparatus according to claim 20, wherein the field mask is arranged at a position deviated from an optical axis of the objective lens group. The center of a light beam that reaches the center of a parallax image projected on the single imaging device via the first objective lens group, the 1-1 reflection surface, the 1-2 reflection surface, and the imaging lens group. A parallax image projected on the single imaging device through a first principal ray, the second objective lens group, the 2-1 reflection surface, the 2-2 reflection surface, and the imaging lens group. When the central ray of the light flux reaching the center of the first objective lens group and the second objective lens group, the outer shape of at least one of the first objective lens group and the second objective lens group is each 22. The stereo imaging device according to claim 1, wherein the stereo imaging device has a non-rotationally symmetric shape closest to the optical axis on a side opposite to a side on which the principal ray is incident.

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