JP3929420B2

JP3929420B2 - Vehicle light amount detection device and vehicle illumination control device

Info

Publication number: JP3929420B2
Application number: JP2003147481A
Authority: JP
Inventors: 英樹塚岡; 賢一藤江; 早苗塚岡
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2003-05-26
Filing date: 2003-05-26
Publication date: 2007-06-13
Anticipated expiration: 2023-05-26
Also published as: JP2004347555A

Description

【０００１】
【発明の属する技術分野】
この発明は、車両用の撮像装置を使用した光量検出装置、及び当該光量検出に基づいて照明を制御する照明制御装置に関するものである。
【０００２】
【従来の技術】
従来、撮像手段を用いて車両外部の明るさを判断して車両制御を行う装置として、例えば特許文献１（特開２００１−２０６２０１号公報）や特許文献２（特開平９−６６８０３号公報）に記載されるようなものがある。
【０００３】
特許文献１では、車両用雨滴検出装置において、カメラから取り込んだ画像が明る過ぎたり暗過ぎたりしないように調整する撮影感度調整機能を有し、暗過ぎればカメラの感度を上げ、明る過ぎれば感度を下げる補正を実行する。これにより、天候の影響あるいはトンネルや方位などの影響を排除する。
【０００４】
また、特許文献２では、ＡＤＡ（Active Drive Assist system）の画像認識において、距離データが異常な場合はカメラのシャタースピードをチェックし、カメラのシャッタースピードが所定値未満で遅い場合は外が暗いことを判断して、オートライト装置を作動することが示されている。
【０００５】
一般に、撮像手段は高価であり、得られる画像情報は様々な用途に使用できるため、撮像手段を複数の用途に兼用することが多い。前記特許文献１や前記特許文献２に記載される装置も例外でなく、撮像手段は複数の用途に兼用されている。
【０００６】
撮像手段の対象及びその用途に関して、撮影の対象を車両の前方の景色とし、その利用用途を白線の検出、ナンバープレートの認識等を行うものが存在し、撮影の対象を車両の後方の景色として、その用途を後方監視モニタとして利用するものが存在する。しかしながらこれらの場合、撮影の対象は車両前方水平方向、後方水平方向等、所定の方向（特に水平方向）に限られる。そのため、現在提案されている装置では、所定の方向（特に水平方向）の景色を撮像範囲とし、得られる所定の方向（特に水平方向）の景色像信号から車両外部の明るさを判断している。
【０００７】
【特許文献１】
特開２００１−２０６２０１号公報
【特許文献２】
特開平９−６６８０３号公報
【０００８】
【発明が解決しようとする課題】
上述のように、現在は、一般に所定の方向、特に水平方向の景色を撮影して得られる画像信号を用いて、車両外部の明るさを判断している。しかし、水平方向の景色には、対向車のヘッドライト、道路際の店舗の照明、看板の照明など様々な光源が含まれるため、明るさの検出に際して誤る可能性が高い。これに比べて、車両上方向の景色には、誤検出の要因となる光源が含まれる可能性は低いので、上方向の景色を撮影して得られる画像信号を用いて、車両外部の明るさを判断すれば、かなり精度が向上すると考えられる。しかしながら、撮影の対象を車両の上方向の景色と限定すれば、撮像手段を他の用途に使えず、車両外部の明るさ判断専用となってしまい、非経済的であると共に汎用性に劣る。
【０００９】
この発明は、上記のような課題を解消するためになされたもので、様々な用途に使用できる所定の方向（特に水平方向）の景色を所定の用途（前方車両認識、白線検出、ナンバープレート認識、後方監視等）に利用しつつ、ノイズの少ない自車周辺の光量を用いて明るさを判断する精度の良い光量検出装置及びそれを利用した照明制御装置を提供するものである。
【００１０】
さらに、車両の上方向の景色を用いた光量検出装置は、現在の環境における明るさを正確に判断することを目的とするため、唯一懸念される点は、車両の前方における明るさが判断できないことであるが、この点における解決案もあわせて提案する。
【００１１】
【課題を解決するための手段】
この発明による車両用光量検出装置は、所定の視野の景色を取り込む撮像レンズと撮像レンズで取り込まれた景色を結像する撮像素子とを備えた撮像手段と、所定の視野以外の外光であって車両周辺の外光を撮像レンズに入射させて所定の視野の景色と同時に撮像手段に取り込むための光学手段と、光学手段を介して撮像手段により取り込まれた車両周辺の外光から車両周辺の光量を検出する光量検出手段を備えたことを特徴とする。
【００１２】
また、この発明による車両用照明制御装置は、所定の視野の景色を取り込む撮像レンズと撮像レンズで取り込まれた景色を結像する撮像素子とを備えた撮像手段と、所定の視野以外の外光であって車両周辺の外光を撮像レンズに入射させて所定の視野の景色と同時に撮像手段に取り込むための光学手段と、光学手段を介して撮像手段により取り込まれた車両周辺の外光から車両周辺の光量を検出する光量検出手段と、光量検出手段により検出された車両周辺の光量に基づいて照明を制御する照明制御手段を備え、光量検出手段は、所定方向の景色のうち遠方の領域の光量も同時に検出し、照明制御手段は、車両周辺の光量と、遠方領域の光量のいずれか一方の検出光量が暗くなったときに照明を点灯することを特徴とする。
【００１３】
【発明の実施の形態】
実施の形態１．
図１はこの発明の実施の形態１による車両用光量検出装置及び照明制御装置の構成を示すブロック図である。
【００１４】
図１において、撮像手段１０は車両外部の景色を画像信号として取り込む車両用カメラ等であって、所定方向の視野２０の景色を取り込む撮像レンズ１１と、撮像レンズ１１で取り込まれた景色を結像する撮像素子１２を備えている。この撮像手段１０は、所定方向の視野の景色を取り込むために設置され、後述する所定の処理を行い、所定の制御を行う。すなわち、例えば、撮像手段１０は、所定方向の景色として車両前方の水平方向の景色を取り込むために設置され、後述する画像処理手段１７が前方障害物検知や走行レーン用の白線検出を行い、追突予防警報制御、車間距離自動制御、レーン逸脱警報制御、自動操縦制御を行う。また、撮像手段１０は、所定方向の景色として車両後方の水平方向の景色を取り込むために設置され、所定の処理として後方障害物検知や白線検出を行い、所定の制御として後退運転支援制御、高速道路における車線変更時の後側方接近車両検出制御を行う。
【００１５】
光学手段１３は、前述の所定の視野以外、特に車両前方又は車両後方の水平方向の視野以外であって、当該車両周辺の外光、特に車両上方の外光を撮像手段１０に取り込むために設置される。光量検出手段１４は、光学手段１３を介して撮像手段１０に取り込まれた外光の明るさから車両周辺の光量を検出する装置である。照明制御手段１５は、光量検出手段１４により検出された車両周辺の光量に基づいてヘッドライト等の照明手段１６による照明を制御するものである。画像処理手段１７は、撮像手段１０により取り込まれた車両前方の水平方向の景色や車両後方の水平方向の景色等に基づいて、前方又は後方障害物の検知や走行レーン用の白線検出を行うためのものである。
【００１６】
図２はこの発明の実施の形態１による撮像手段及び光学手段の設置例を示す構成図である。撮像手段１０は、車両のフロントガラス２１越しに車両前方の水平方向視野２０ａの景色が撮像できるように設置されている。また、光学手段１３として乱反射層１３ａを使用し、この乱反射層１３ａは撮像手段１０の視野の一部であるフロントガラス２１の表面に、すりガラス状の加工を施すことにより構成している。また、この乱反射層１３ａは車両上方からの光を集光するように設置されている。
【００１７】
次に、図１及び図２の構成において本実施の形態の動作を説明する。車両上方からの入射光は、フロントガラス２１に設置した乱反射層１３ａで乱反射して撮像レンズ１１に入射し、撮像素子１２に像を結ぶ。車両前方の水平方向視野２０ａからの入射光は、フロントガラス２１を透過して撮像レンズ１１に入射し、撮像素子１２に像を結ぶ。撮像手段１０は、撮像素子１２上に結ばれた像を画像信号に変えて出力する。撮像手段１０より出力される画像信号は、光量検出手段１４と画像処理手段１７に入力され、光量検出装置１４では車両上方の光像を用いて光量の検出を行い、画像処理手段１７では車両前方の景色像を用いて前方又は後方の障害物検知や白線の検出を行う。
【００１８】
図３は撮像手段１０より出力される画像信号によって構成される画像の一例である。図３に示すように、撮像手段１０により得られた画像５０には、車両上方の光像５１と車両前方の景色像５２が含まれており、車両上方の光像５１は、前方障害物検知や白線検知等の処理に使用される景色像の妨げとならない画像上方の一部に撮像されるようにする。
【００１９】
光量検出手段１４は、車両上方の光像５１の画像信号を用いて、各画素の輝度の平均値を求める。求められた輝度の平均値は、車両外部の光量を表している。図４は上記輝度の平均値すなわち車両外部の光量を時間軸上で表わしたグラフである。照明制御手段１５は、光量検出手段１４で求められた結果を用いて、照明の制御を行う。照明が消灯されている場合は、照明を点灯するための点灯閾値ＴＨonと光量（輝度の平均値）の比較を行い、光量（輝度の平均値）が点灯閾値ＴＨon以下であれば、照明を点灯させる制御を行う。照明が点灯されている場合は、照明を消灯するための消灯閾値ＴＨoffと光量（輝度の平均値）の比較を行い、光量（輝度の平均値）が消灯閾値ＴＨoff以上であれば、照明を消灯させる制御を行う。この場合、点灯閾値ＴＨonは消灯閾値ＴＨoffより小さな値に設定し、ヒステリシスを持たせておくことで、一時的な光量の変化による影響を受けにくくしておく。
【００２０】
画像処理手段１７は、車両前方の景色像５２の画像信号を用いて、前記先行車両、対向車両、障害物の検知や、白線の検出を行う。これらの検知処理は既知の技術であるため、説明は省略する。
【００２１】
図２に示す構成では、光学手段１３である乱反射層１３ａをフロントガラス２１上に設置し、当該乱反射層１３ａを介して車両上方の光像を撮像手段１０に照射させるようにしたが、図５に示すように、フロントガラス２１と撮像手段１０の間に、すりガラス等の乱反射体１３ｂを設置し、当該乱反射体１３ｂを介して車両上方の光像を撮像手段１０に照射させるような構成を採用しても良い。また、図６に示すように、フロントガラス２１と撮像手段１０の間に、鏡等の反射板１３ｃを設置し、当該反射板１３ｃを介して車両上方の光像を撮像手段に照射させるような構造でも同様の効果を得ることができる。なお、図２に示す構成によれば、光学手段１３である乱反射層１３ａを撮像手段１０であるカメラを別体で構成することができ、撮像手段１０の装置構成がシンプルになる。一方、図５又は図６の構成では、光学手段１３である乱反射体１３ｂ又は反射板１３ｃを撮像手段１０であるカメラに取り付けることもでき、更に、車両への設置位置の自由度が広がる。
【００２２】
上記説明では、撮像手段１０の撮像した画像信号を白線検知処理等に使用しているため、撮像手段１０は車両前方の景色が撮影できるように設置しているが、撮像手段１０の用途に応じた設置を行えばよい。例えば、後方監視モニタに用いる場合は、撮像手段１０を後方景色が撮影できるように設置すればよい。また、光学手段１３を用いて車両上方の光像を照射させる範囲も、画像の上部に限定せず、兼用する用途に応じて設定すればよい。
【００２３】
以上のように、実施の形態１によれば、所定の視野の景色を取り込むための撮像手段１０と、所定の視野以外の外光であって車両周辺の外光を撮像手段１０に取り込むための光学手段１３と、光学手段１３を介して撮像手段１０により取り込まれた車両周辺の外光から車両周辺の光量を検出する光量検出手段を備えたので、所定の視野の景色と車両周辺の外光の画像が１つの撮像手段１０から同時に得られ、車両周辺の光は、車両周辺の明るさを判断する用途に使用し、所定の視野の景色は、前方又は後方障害物検知や、先行車又は後行車検知や、白線検知等その他の用途に用いることができる。
【００２４】
特に、車両周辺の外光としてノイズの少ない車両上方の外光を検出することにより、車両周辺の外部の明るさを正確に判断することができる。
【００２５】
また、光学手段１３として、フロントガラス等の表面に加工した乱反射層を使用することにより、この乱反射層は車両の周辺の光を乱反射させて、撮像手段１０に取り込むので、１つの撮像手段１０から、車両の周辺の光量と所定方向（特に水平方向）の景色像を同時に得ることができる。そのため、車両周辺の光は、車両外部の明るさを判断する光量検出に用い、所定方向（水平方向）の景色像は、その他の用途に用いることができる。
【００２６】
また、光学手段１３として、フロントガラス等と撮像手段の間に設置された乱反射体を使用することにより、設置された乱反射体は、車両周辺の光を乱反射させて、撮像手段から監視させるので、１つの撮像手段から、車両周辺の光と所定方向（特に、水平方向）の景色像を同時に得ることができる。そのため、車両周辺の光は、車両外部の明るさを判断する光量検出に用い、所定方向（水平方向）の景色像は、その他の用途に用いることができる。
【００２７】
更に、光学手段１３として、フロントガラス等と撮像手段の間に設置された反射板を使用することにより、設置された反射曲面は、車両の上方向等の景色を反射させて、撮像手段に照射するので、１つの撮像手段から、車両の上方向などの景色像と所定方向（特に水平方向）の景色像を同時に得ることができる。そのため、上方向等の景色像は、車両外部の明るさを判断する光量検出に用い、所定方向（水平方向）の景色像は、その他の用途に用いることができる。
【００２８】
実施の形態２．
図７はこの発明の実施の形態２による車両用光量検出装置及び照明制御装置の構成を示すブロック図である。
【００２９】
図７において、光量検出手段１４は、撮像手段１０より得られる画像信号を用いて、車両上方の光像５１の各画素の輝度の平均値を検出する車両周辺光量検出部１４ａと、車両前方の景色像５２の一部に設定された光量検出範囲６０の各画素の輝度の平均値を検出する車両前方光量検出部１４ｂを備えている。ここで、車両前方光量検出部１４ｂの光量検出範囲６０は、当該車両が所定時間後に到達する領域の外部の明るさを検出するために設定されるものであり、車速信号等に基づいて設定される。車両上方の光像５１の平均輝度値は、車両上方の光量であり、車両周辺の外部の明るさを表している。また、光量検出範囲６０の平均輝度値は車両前方の光量であり、所定時間後の車両外部の明るさを表している。
【００３０】
図８は撮像手段１０より出力される画像信号によって構成される画像の一例である。図８に示すように、撮像手段１０により得られた画像５０には、車両上方の光像５１と、車両前方の景色像５２と、光量検出範囲６０が含まれいる。光量検出範囲６０は、前述のように所定時間後の車両の到達する位置の外部の明るさが判断できるように、車速に応じて設定される。例えば、１秒後の状況が判断できるように、時速１００ｋｍで走行していれば２８ｍより遠方の領域、時速３６ｋｍで走行していれば１０ｍより遠方の領域というように、車速に応じて設定される。
【００３１】
照明制御手段１５は、車両周辺光量検出部１４ａより得られる車両上方の光量と、車両前方光量検出部１４ｂより得られる車両前方の光量をそれぞれ閾値と比較して、それぞれに明暗の判断を行う。比較の際の閾値は、車両前方の光量に応じた値と、車両上方の光量に応じた値をそれぞれに設定し、光量が閾値以上であれば明、閾値以下であれば暗と判断する。その結果を用いて、図９に示す照明制御を行う。前方及び上方のいずれも暗と判断された場合は、夜間やトンネル内部など照明を必要とする状態であると考えられるので、照明制御手段１５は照明点灯の制御信号を発する。前方が暗、上方が明と判断された場合は、トンネルなどが存在し所定時間（１秒後）には照明が必要となる状態であると考えられるので、照明制御手段１５は照明点灯の制御信号を発する。前方が明、上方が暗と判断された場合は、夜間やトンネル内部など照明を必要とする状態であるが、光量検出範囲６０には、対向車のヘッドライトなど光源が含まれ、正確な光量が得られなかったと考えられるので、照明制御手段１５は照明点灯の制御信号を発する。前方及び上方のいずれも明と判断された場合は、昼間など照明を必要としない状態であると考えられるので、照明消灯の制御信号を発する。照明手段１６は、照明制御手段１５より発せられる制御信号に基づいて点消灯を行う。
【００３２】
上記説明では、トンネル進入のような状況においては、約１秒前に照明の点灯を行いたいので、所定時間として約１秒を設定し、光量検出範囲６０は約１秒後に通過する景色に設定しているが、これに限定せず、用途に応じて設定すればよい。
【００３３】
以上のように実施の形態２によれば、車両周辺の光量と前方水平方向の画像の一部を用いて明るさの判断を行うため、車両周辺の光量からは現在の車両外部の明るさを正確に判断することができ、前方水平方向の画像の一部からは、先方の明るさを判断することができる。そのため、現在の車両外部の明るさを正確に把握しつつ、車両周辺の光量を先読みすることが可能な光量検出装置を実現することができる。また、前方水平方向の画像は様々な用途に用いることができるため、撮像手段を汎用的に利用することができる。
【００３４】
また、光量検出装置から得られる現在の車両外部の明るさと、先読みされた車両外部の明るさを用いて、照明の点消灯の制御が行える。そのため、トンネル進入時等では早目の点灯が可能で、精度の良い照明制御を行うことができる。
【００３５】
【発明の効果】
以上のように、この発明によれば、所定の視野の景色を取り込む撮像レンズと前記撮像レンズで取り込まれた景色を結像する撮像素子とを備えた撮像手段と、所定の視野以外の外光であって車両周辺の外光を前記撮像レンズに入射させて前記所定の視野の景色と同時に撮像手段に取り込むための光学手段と、光学手段を介して撮像手段により取り込まれた車両周辺の外光から当該車両周辺の光量を検出する光量検出手段を備えたので、１つの撮像手段から、車両周辺の光量と所定方向（特に水平方向）の景色画像を同時に得ることができる。そのため、誤検出の要因が少ない車両周辺の光量を用いて車両外部の明るさを判断することができる。また、所定方向（特に水平方向）の景色像は、白線検知装置やナンバープレート認識装置などに用いることができる。このように、本発明によれば、精度の良い光量検出装置を実現しつつ、撮像手段を光量検出装置だけでなく、様々な用途に利用することを可能とする。
【００３６】
また、車両周辺の光量と前方水平方向の画像の一部を用いて明るさの判断を行うため、車両周辺の光量からは現在の車両外部の明るさを正確に判断することができ、前方水平方向の画像の一部からは、先方の明るさを判断することができる。そのため、現在の車両外部の明るさを正確に把握しつつ、車両周辺の光量を先読みすることが可能な光量検出装置を実現することができる。また、前方水平方向の画像は様々な用途に用いることができるため、撮像手段を汎用的に利用することができる。
【００３７】
また、光量検出装置から得られる現在の車両外部の明るさと、先読みされた車両外部の明るさを用いて、照明の点消灯の制御が行える。そのため、トンネル進入時等では早目の点灯が可能で、精度の良い照明制御を行うことができる。
【図面の簡単な説明】
【図１】この発明の実施の形態１による車両用光量検出装置及び照明制御装置の構成を示すブロック図である。
【図２】この発明の実施の形態１による撮像手段及び光学手段の設置例を示す構成図である。
【図３】この発明の実施の形態１による撮像手段により出力される画像信号によって構成される画像の一例を示す図である。
【図４】この発明の実施の形態１により求められた車両外部の光量を時間軸上で表現した図である。
【図５】この発明の実施の形態１による撮像手段及び光学手段の他の設置例を示す構成図である。
【図６】この発明の実施の形態１による撮像手段及び光学手段の他の設置例を示す構成図である。
【図７】この発明の実施の形態２による車両用光量検出装置及び照明制御装置の構成を示すブロック図である。
【図８】この発明の実施の形態２による撮像手段により出力される画像信号によって構成される画像の一例を示す図である。
【図９】この発明の実施の形態２による照明制御手段の制御を示す図である。
【符号の説明】
１０撮像手段、１１撮像レンズ、１２撮像素子、１３光学手段、
１３ａ乱反射層、１３ｂ乱反射体、１３ｃ反射板、１４光量検出手段、
１５照明制御手段、１６照明手段、１７画像処理手段、２０撮像手段の視野、
２１フロントガラス、５０撮像手段の画面、５１車両上方の光像、
５２車両前方の景色像、６０光量検出範囲。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light amount detection device that uses an imaging device for a vehicle, and an illumination control device that controls illumination based on the light amount detection.
[0002]
[Prior art]
Conventionally, as an apparatus for performing vehicle control by determining brightness outside a vehicle using an imaging unit, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2001-206201) and Patent Document 2 (Japanese Patent Laid-Open No. 9-66803). Some are described.
[0003]
In Patent Document 1, the vehicle raindrop detection apparatus has a photographing sensitivity adjustment function for adjusting an image captured from a camera so that the image is not too bright or too dark. If the image is too dark, the camera sensitivity is increased, and if the image is too bright, the sensitivity is increased. Perform correction to lower This eliminates the influence of weather or the influence of tunnels and headings.
[0004]
Also, in Patent Document 2, in ADA (Active Drive Assist system) image recognition, when the distance data is abnormal, the camera shutter speed is checked, and when the camera shutter speed is lower than a predetermined value, the outside is dark. It is shown that the auto light device is activated.
[0005]
In general, the imaging means is expensive, and the obtained image information can be used for various purposes. Therefore, the imaging means is often used for a plurality of purposes. The devices described in Patent Document 1 and Patent Document 2 are no exception, and the imaging unit is also used for a plurality of purposes.
[0006]
Regarding the object of the imaging means and its application, the object to be imaged is the scenery in front of the vehicle, the use application is to detect white lines, recognize the license plate, etc., and the object to be imaged is the scenery behind the vehicle There are those that use the application as a rear monitor. However, in these cases, the object of photographing is limited to a predetermined direction (particularly the horizontal direction) such as the vehicle front horizontal direction and the rear horizontal direction. Therefore, in the currently proposed apparatus, a scene in a predetermined direction (particularly in the horizontal direction) is used as an imaging range, and the brightness outside the vehicle is determined from the obtained scene image signal in the predetermined direction (particularly in the horizontal direction). .
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-206201 [Patent Document 2]
JP-A-9-66803 [0008]
[Problems to be solved by the invention]
As described above, at present, the brightness outside the vehicle is generally determined using an image signal obtained by photographing a landscape in a predetermined direction, particularly a horizontal direction. However, since the landscape in the horizontal direction includes various light sources, such as headlights of oncoming vehicles, store lighting on the road, and signboard lighting, there is a high possibility of errors in detecting brightness. Compared to this, since the scenery above the vehicle is unlikely to contain a light source that causes false detection, the brightness of the exterior of the vehicle is determined using the image signal obtained by photographing the scenery above. If it is judged, the accuracy is considered to be improved considerably. However, if the object to be photographed is limited to the scenery in the upward direction of the vehicle, the image pickup means cannot be used for other purposes and is dedicated to the brightness determination outside the vehicle, which is uneconomical and inferior in versatility.
[0009]
The present invention has been made in order to solve the above-described problems. A landscape in a predetermined direction (especially a horizontal direction) that can be used for various applications is used for a predetermined application (front vehicle recognition, white line detection, license plate recognition). The present invention provides a light amount detection device with high accuracy for determining brightness using the light amount around the own vehicle with less noise while using it for rear monitoring, etc., and an illumination control device using the same.
[0010]
Furthermore, since the light amount detection device using the landscape in the upward direction of the vehicle is intended to accurately determine the brightness in the current environment, the only concern is that the brightness in front of the vehicle cannot be determined. However, we also propose a solution for this point.
[0011]
[Means for Solving the Problems]
The vehicle light quantity detection device according to the present invention includes an imaging unit including an imaging lens that captures a scene of a predetermined field of view and an imaging element that forms an image of the scene captured by the imaging lens, and external light other than the predetermined field of view. The optical means for making the outside light around the vehicle incident on the imaging lens and taking it into the imaging means at the same time as the scenery of the predetermined field of view, and the outside light around the vehicle taken in by the imaging means through the optical means A light amount detecting means for detecting the light amount is provided.
[0012]
Further, the present invention vehicle lighting control apparatus according to an image pickup means having an image pickup device for imaging the scene captured by the imaging lens and the imaging lens for capturing a view of the predetermined field-of-view, the outside light other than the predetermined field of view An optical means for allowing external light around the vehicle to enter the imaging lens and taking it into the imaging means simultaneously with a predetermined field of view, and from outside light around the vehicle taken by the imaging means via the optical means A light amount detecting means for detecting the amount of light in the periphery, and an illumination control means for controlling the illumination based on the light amount around the vehicle detected by the light amount detecting means; The amount of light is also detected at the same time, and the illumination control means turns on the illumination when the detected light amount of either the light amount in the vicinity of the vehicle or the light amount in the far region becomes dark.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a block diagram showing the configuration of a vehicle light quantity detection device and an illumination control device according to Embodiment 1 of the present invention.
[0014]
In FIG. 1, an imaging unit 10 is a vehicle camera or the like that captures scenery outside the vehicle as an image signal. The imaging lens 11 captures scenery in a field of view 20 in a predetermined direction, and images the scenery captured by the imaging lens 11. An image sensor 12 is provided. The imaging means 10 is installed to capture a field of view in a predetermined direction, performs a predetermined process to be described later, and performs a predetermined control. That is, for example, the imaging means 10 is installed to capture a landscape in the horizontal direction ahead of the vehicle as a landscape in a predetermined direction, and the image processing means 17 described later performs forward obstacle detection and white line detection for a driving lane, and rear-end collision. Preventive warning control, inter-vehicle distance automatic control, lane departure warning control, and autopilot control are performed. The imaging means 10 is installed to capture a landscape in the horizontal direction behind the vehicle as a landscape in a predetermined direction, performs rear obstacle detection and white line detection as a predetermined process, and performs reverse driving support control and high speed as predetermined control. Carry out rear side approaching vehicle detection control when changing lanes on the road.
[0015]
The optical means 13 is installed in order to capture the outside light around the vehicle, particularly outside the vehicle, into the image pickup means 10 other than the above-described predetermined field of view, particularly outside the horizontal field of view in front of or behind the vehicle. Is done. The light amount detection unit 14 is a device that detects the amount of light around the vehicle from the brightness of external light captured by the imaging unit 10 via the optical unit 13. The illumination control means 15 controls illumination by the illumination means 16 such as a headlight based on the light quantity around the vehicle detected by the light quantity detection means 14. The image processing means 17 detects a front or rear obstacle or detects a white line for a driving lane based on the horizontal scenery in front of the vehicle, the horizontal scenery in the rear of the vehicle, or the like captured by the imaging means 10. belongs to.
[0016]
FIG. 2 is a block diagram showing an installation example of the imaging means and optical means according to Embodiment 1 of the present invention. The imaging means 10 is installed so that the scenery of the horizontal visual field 20a in front of the vehicle can be imaged through the windshield 21 of the vehicle. Further, the irregular reflection layer 13a is used as the optical means 13, and the irregular reflection layer 13a is constituted by applying a ground glass processing to the surface of the windshield 21 which is a part of the field of view of the imaging means 10. The irregular reflection layer 13a is installed so as to collect light from above the vehicle.
[0017]
Next, the operation of the present embodiment in the configuration of FIGS. 1 and 2 will be described. Incident light from above the vehicle is diffusely reflected by the irregular reflection layer 13 a installed on the windshield 21, enters the imaging lens 11, and forms an image on the imaging element 12. Incident light from the horizontal visual field 20a in front of the vehicle passes through the windshield 21 and enters the imaging lens 11, and forms an image on the imaging element 12. The imaging means 10 converts the image formed on the imaging element 12 into an image signal and outputs it. The image signal output from the imaging unit 10 is input to the light amount detection unit 14 and the image processing unit 17. The light amount detection device 14 detects the light amount using the light image above the vehicle, and the image processing unit 17 detects the front of the vehicle. The front or rear obstacle detection or white line detection is performed using the scenery image of
[0018]
FIG. 3 is an example of an image constituted by an image signal output from the imaging means 10. As shown in FIG. 3, the image 50 obtained by the imaging means 10 includes a light image 51 above the vehicle and a landscape image 52 in front of the vehicle. The light image 51 above the vehicle is detected by front obstacle detection. Or a white line detection or the like, the image is captured in a part above the image that does not interfere with the scenery image.
[0019]
The light quantity detection means 14 obtains the average value of the luminance of each pixel using the image signal of the light image 51 above the vehicle. The obtained average value of luminance represents the amount of light outside the vehicle. FIG. 4 is a graph showing the average value of the brightness, that is, the amount of light outside the vehicle on the time axis. The illumination control unit 15 controls the illumination using the result obtained by the light amount detection unit 14. When the illumination is turned off, the lighting threshold THon for turning on the illumination is compared with the amount of light (average value of luminance). If the amount of light (average value of luminance) is less than the lighting threshold THon, the illumination is turned on. To control. When the illumination is turned on, the turn-off threshold THoff for turning off the illumination is compared with the amount of light (average luminance), and if the amount of light (average luminance) is equal to or greater than the turn-off threshold THoff, the illumination is turned off. To control. In this case, the lighting threshold value THon is set to a value smaller than the extinguishing threshold value THoff, and hysteresis is provided so that the lighting threshold value THon is hardly affected by a temporary light amount change.
[0020]
The image processing unit 17 detects the preceding vehicle, the oncoming vehicle, the obstacle, and the white line using the image signal of the landscape image 52 in front of the vehicle. Since these detection processes are known techniques, description thereof is omitted.
[0021]
In the configuration shown in FIG. 2, the irregular reflection layer 13a, which is the optical means 13, is installed on the windshield 21, and the light image above the vehicle is irradiated to the imaging means 10 through the irregular reflection layer 13a. As shown in the figure, a diffused reflector 13b such as ground glass is installed between the windshield 21 and the imaging means 10, and a configuration is adopted in which the imaging means 10 is irradiated with a light image above the vehicle via the irregular reflector 13b. You may do it. Further, as shown in FIG. 6, a reflection plate 13c such as a mirror is installed between the windshield 21 and the image pickup means 10, and the image pickup means is irradiated with a light image above the vehicle via the reflection plate 13c. The same effect can be obtained with the structure. In addition, according to the configuration shown in FIG. 2, the irregular reflection layer 13a that is the optical means 13 can be configured separately from the camera that is the imaging means 10, and the apparatus configuration of the imaging means 10 is simplified. On the other hand, in the configuration of FIG. 5 or FIG. 6, the irregular reflector 13b or the reflector 13c, which is the optical means 13, can be attached to the camera, which is the imaging means 10, and the degree of freedom of the installation position on the vehicle is further increased.
[0022]
In the above description, since the image signal captured by the imaging unit 10 is used for white line detection processing or the like, the imaging unit 10 is installed so that a scene in front of the vehicle can be captured. Just install it. For example, when used for a rear monitoring monitor, the image pickup means 10 may be installed so that a rear view can be taken. Further, the range in which the optical image 13 is used to irradiate the light image above the vehicle is not limited to the upper part of the image, but may be set according to the intended use.
[0023]
As described above, according to the first embodiment, the imaging unit 10 for capturing a scene with a predetermined field of view, and the external light outside the predetermined field of view and for capturing outside light around the vehicle into the imaging unit 10. Since the optical means 13 and the light quantity detection means for detecting the light quantity around the vehicle from the external light around the vehicle captured by the imaging means 10 via the optical means 13 are provided, the scenery of the predetermined field of view and the external light around the vehicle Are simultaneously obtained from one imaging means 10, and the light around the vehicle is used for the purpose of judging the brightness around the vehicle, and the scenery of a predetermined field of view is the detection of obstacles ahead or behind, It can be used for other purposes such as detection of a following vehicle and white line detection.
[0024]
In particular, it is possible to accurately determine the external brightness around the vehicle by detecting the outside light above the vehicle with little noise as the outside light around the vehicle.
[0025]
Further, by using an irregular reflection layer processed on the surface of a windshield or the like as the optical means 13, the irregular reflection layer diffuses light around the vehicle and takes it into the imaging means 10. The light quantity around the vehicle and a landscape image in a predetermined direction (particularly in the horizontal direction) can be obtained simultaneously. Therefore, the light around the vehicle can be used for light amount detection for determining the brightness outside the vehicle, and the landscape image in a predetermined direction (horizontal direction) can be used for other purposes.
[0026]
Further, by using a diffuse reflector installed between the windshield or the like and the imaging means as the optical means 13, the installed irregular reflector diffusely reflects the light around the vehicle and monitors it from the imaging means. From one image pickup means, it is possible to simultaneously obtain light around the vehicle and a landscape image in a predetermined direction (particularly in the horizontal direction). Therefore, the light around the vehicle can be used for light amount detection for determining the brightness outside the vehicle, and the landscape image in a predetermined direction (horizontal direction) can be used for other purposes.
[0027]
Further, by using a reflector installed between the windshield or the like and the imaging means as the optical means 13, the installed reflection curved surface reflects the scenery such as the upward direction of the vehicle and irradiates the imaging means. Therefore, it is possible to simultaneously obtain a landscape image such as an upward direction of the vehicle and a landscape image in a predetermined direction (particularly the horizontal direction) from one image pickup means. Therefore, the landscape image in the upward direction or the like can be used for light amount detection for determining the brightness outside the vehicle, and the landscape image in a predetermined direction (horizontal direction) can be used for other purposes.
[0028]
Embodiment 2. FIG.
FIG. 7 is a block diagram showing the configuration of the vehicle light quantity detection device and illumination control device according to Embodiment 2 of the present invention.
[0029]
In FIG. 7, the light quantity detection means 14 uses the image signal obtained from the imaging means 10, a vehicle peripheral light quantity detection unit 14 a that detects the average value of the luminance of each pixel of the light image 51 above the vehicle, A vehicle front light amount detection unit 14b that detects an average value of the luminance of each pixel in the light amount detection range 60 set in a part of the landscape image 52 is provided. Here, the light amount detection range 60 of the vehicle front light amount detection unit 14b is set to detect the brightness outside the area where the vehicle reaches after a predetermined time, and is set based on a vehicle speed signal or the like. The The average luminance value of the light image 51 above the vehicle is the amount of light above the vehicle and represents the external brightness around the vehicle. The average luminance value in the light amount detection range 60 is the light amount in front of the vehicle and represents the brightness outside the vehicle after a predetermined time.
[0030]
FIG. 8 is an example of an image constituted by an image signal output from the imaging means 10. As shown in FIG. 8, the image 50 obtained by the imaging unit 10 includes a light image 51 above the vehicle, a landscape image 52 in front of the vehicle, and a light amount detection range 60. The light quantity detection range 60 is set according to the vehicle speed so that the brightness outside the position where the vehicle reaches after a predetermined time can be determined as described above. For example, in order to be able to judge the situation after 1 second, it is set according to the vehicle speed, such as a region farther than 28 m if traveling at 100 km / h, and a region farther than 10 m if traveling at 36 km / h. The
[0031]
The illumination control means 15 compares the light amount above the vehicle obtained from the vehicle peripheral light amount detection unit 14a and the light amount ahead of the vehicle obtained from the vehicle front light amount detection unit 14b with a threshold value, and makes a light / dark judgment for each. As the threshold value for comparison, a value corresponding to the light amount in front of the vehicle and a value corresponding to the light amount above the vehicle are set, respectively. The illumination control shown in FIG. 9 is performed using the result. If both the front and the upper are determined to be dark, it is considered that lighting is required such as at night or inside the tunnel, so the lighting control means 15 issues a lighting lighting control signal. If it is determined that the front is dark and the upper is bright, a tunnel or the like exists and it is considered that illumination is necessary for a predetermined time (after one second), so the illumination control means 15 controls illumination lighting. Send a signal. If it is determined that the front is bright and the upper is dark, it is necessary to illuminate such as at night or inside the tunnel. However, the light amount detection range 60 includes a light source such as a headlight of an oncoming vehicle, and an accurate light amount. Therefore, the illumination control means 15 issues a lighting control signal. If it is determined that both the front and the upper are bright, it is considered that the lighting is not necessary, such as daytime, and a control signal for turning off the lighting is issued. The illumination means 16 turns on and off based on a control signal issued from the illumination control means 15.
[0032]
In the above description, in a situation such as entering a tunnel, since it is desired to turn on the light about 1 second before, about 1 second is set as the predetermined time, and the light amount detection range 60 is set to a scenery that passes after about 1 second. However, the present invention is not limited to this, and may be set according to the application.
[0033]
As described above, according to the second embodiment, the brightness is determined using the amount of light around the vehicle and a part of the image in the front horizontal direction. It is possible to determine accurately, and it is possible to determine the brightness of the other side from a part of the image in the front horizontal direction. Therefore, it is possible to realize a light amount detection device that can pre-read the amount of light around the vehicle while accurately grasping the current brightness outside the vehicle. Further, since the image in the front horizontal direction can be used for various purposes, the imaging means can be used for general purposes.
[0034]
In addition, the lighting on / off control of the illumination can be performed using the current brightness outside the vehicle obtained from the light quantity detection device and the previously read brightness outside the vehicle. Therefore, early lighting is possible when entering a tunnel, etc., and accurate illumination control can be performed.
[0035]
【The invention's effect】
As described above, according to the present invention, the imaging means including the imaging lens that captures the scenery of the predetermined field of view, the imaging device that images the scenery captured by the imaging lens, and external light other than the predetermined field of view An optical means for causing ambient light around the vehicle to enter the imaging lens and capturing it into the imaging means simultaneously with the scenery of the predetermined field of view, and external light around the vehicle captured by the imaging means via the optical means Since the light amount detecting means for detecting the light amount around the vehicle is provided, the light amount around the vehicle and a landscape image in a predetermined direction (particularly in the horizontal direction) can be obtained simultaneously from one imaging means. Therefore, the brightness outside the vehicle can be determined using the amount of light around the vehicle that is less likely to cause erroneous detection. A landscape image in a predetermined direction (particularly in the horizontal direction) can be used for a white line detection device, a license plate recognition device, or the like. As described above, according to the present invention, it is possible to use the imaging unit for various purposes as well as the light amount detection device while realizing a highly accurate light amount detection device.
[0036]
In addition, since the brightness is determined using the amount of light around the vehicle and a part of the image in the front horizontal direction, the current brightness outside the vehicle can be accurately determined from the amount of light around the vehicle. The brightness of the other side can be determined from a part of the image in the direction. Therefore, it is possible to realize a light amount detection device that can pre-read the amount of light around the vehicle while accurately grasping the current brightness outside the vehicle. Further, since the image in the front horizontal direction can be used for various purposes, the imaging means can be used for general purposes.
[0037]
In addition, the lighting on / off control of the illumination can be performed using the current brightness outside the vehicle obtained from the light quantity detection device and the previously read brightness outside the vehicle. Therefore, early lighting is possible when entering a tunnel, etc., and accurate illumination control can be performed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a vehicle light quantity detection device and an illumination control device according to Embodiment 1 of the present invention.
FIG. 2 is a configuration diagram showing an installation example of an imaging unit and an optical unit according to Embodiment 1 of the present invention.
FIG. 3 is a diagram showing an example of an image constituted by an image signal output by an imaging unit according to Embodiment 1 of the present invention.
FIG. 4 is a diagram representing on the time axis the amount of light outside the vehicle determined according to the first embodiment of the present invention.
FIG. 5 is a configuration diagram showing another installation example of the imaging unit and the optical unit according to Embodiment 1 of the present invention.
FIG. 6 is a configuration diagram showing another installation example of the imaging means and the optical means according to the first embodiment of the present invention.
FIG. 7 is a block diagram showing a configuration of a vehicle light quantity detection device and an illumination control device according to Embodiment 2 of the present invention.
FIG. 8 is a diagram showing an example of an image configured by an image signal output by an imaging unit according to Embodiment 2 of the present invention.
FIG. 9 is a diagram showing control of illumination control means according to Embodiment 2 of the present invention.
[Explanation of symbols]
10 imaging means, 11 imaging lens, 12 imaging element, 13 optical means,
13a diffuse reflection layer, 13b diffuse reflector, 13c reflector, 14 light quantity detection means,
15 illumination control means, 16 illumination means, 17 image processing means, 20 field of view of imaging means,
21 windshield, 50 screen of imaging means, 51 light image above the vehicle,
52 Landscape image in front of the vehicle, 60 light intensity detection range.

Claims

An imaging unit including an imaging lens that captures a scene of a predetermined field of view, and an imaging element that forms an image of the scene captured by the imaging lens; and external light that is outside the predetermined field of view and that is outside the vehicle. Optical means for entering the image pickup lens and taking in the image pickup means simultaneously with the scenery of the predetermined field of view, and external light around the vehicle taken in by the image pickup means via the optical means A vehicle light quantity detection device comprising a light quantity detection means for detecting a light quantity.

The landscape of the predetermined field of view is a landscape in a horizontal direction in front of or behind the vehicle, and the outside light around the vehicle is outside light above the vehicle. Vehicle light quantity detection device.

3. The vehicle light quantity detection device according to claim 1, wherein the optical means is a diffuse reflection layer installed on a windshield or rear glass of the vehicle.

3. The vehicle light amount detection device according to claim 1, wherein the optical means is a diffuse reflector disposed between a windshield or a rear glass of the vehicle and the imaging means.

3. The vehicle light amount detection device according to claim 1, wherein the optical unit is a reflection plate installed between a windshield or a rear glass of the vehicle and the imaging unit.

6. The vehicle light amount detection device according to claim 1, wherein the light amount detection unit simultaneously detects a light amount of a distant region in the scenery in the predetermined direction.

An imaging unit including an imaging lens that captures a scene of a predetermined field of view, and an imaging element that forms an image of the scene captured by the imaging lens; and external light that is outside the predetermined field of view and that is outside the vehicle. Optical means for entering the image pickup lens and taking in the image pickup means simultaneously with the scenery of the predetermined field of view, and external light around the vehicle taken in by the image pickup means via the optical means An illumination control device for a vehicle, comprising: a light amount detection unit that detects a light amount; and an illumination control unit that controls illumination based on a light amount around the vehicle detected by the light amount detection unit.

The light amount detecting means simultaneously detects a light amount in a distant area of the scenery in the predetermined direction, and the illumination control means detects a light amount detected in one of the light amount around the vehicle and the light amount in the distant area. The vehicle lighting control device according to claim 7, wherein the lighting is turned on when the vehicle is turned on.