JP4034548B2 - Image creation device - Google Patents

Description

次に、プロセッサ１０１は、算出した第２のヨーレートω₂ および受信した速度Ｖを次式（４）および（５）に代入して、座標値ｘ_CPおよびｙ_CPを算出する。なお、本実施形態では、座標値ｚ_CPは、時間に対して一定値（つまり、ｚ_CP0 ）とみなせるので、算出しない。
【数２】

上式（４）および（５）において、δは車両Ｍの重心の横滑り角であり、駐車時のように車両Ｍが低速走行している場合には、０とみなせる。座標値ｘ_CPおよびｙ_CPの算出後、プロセッサ１０１は、初期位置Ｐ₀ から現在位置Ｐまでの移動量ＴＡ（ｘ_CP−ｘ_CP0 ，ｙ_CP−ｙ_CP0 ）を算出する。
【００４７】
ステップＳ１１の次に、プロセッサ１０１は、以上の移動量ＴＡを使って、現在保持している最適軌跡ＬＴを変形して、現在の最適軌跡ＬＴを作成し保持する（ステップＳ１２）。より具体的には、車両Ｍは基準時刻ｔ_REF から現在時刻ｔ_CPの間に上述の移動量ＴＡだけ移動している。最適軌跡ＬＴは、上述のように、現在位置Ｐ_CPから始まる性質を有するから、保持中の最適軌跡ＬＴにおいて、この移動量ＴＡに相当する分は不必要となる。
【００４８】
例えば、図１３に示すように、基準時刻ｔ_REF の時点では、最適軌跡ＬＴ（選択オブジェクトＢ_N ）の開始線Ｌ_STを規定する座標値Ｐ_v1およびＰ_vrは必要である。しかしながら、時間経過と共に、車両Ｍは、基準時刻ｔ_REF の時点の最適軌跡ＬＴ上を移動していくような感じになるので、基準時刻ｔ_REF が過ぎてしまえば、座標値Ｐ_v1およびＰ_vrは不要になる。そのため、初めて実行されるステップＳ１２では、プロセッサ１０１は、保持中の最適経路ＬＴを構成する座標列Ｐ_v1〜Ｐ_vrから、車両Ｍが基準時刻ｔ_REF から現在時刻ｔ_CPまでに移動した領域Ｒ_M1に含まれる座標値を削除して、現在の最適軌跡ＬＴを作成する。ここで、移動領域Ｒ_M1は、ｘ_v1以上ｘ_v1＋（ｘ_CP−ｘ_CP0 ）以下の範囲である。
【００４９】
また、２回目以降に実行されるステップＳ１２においても、初回の場合と同様に、プロセッサ１０１は、保持中の最適経路ＬＴを構成する座標列から、車両Ｍが基準時刻ｔ_REF から現在時刻ｔ_CPまでに移動した領域Ｒ_M1に含まれる座標値を削除して、現在の最適軌跡ＬＴを作成する。
【００５０】
次に、プロセッサ１０１は、予想走行軌跡ＥＴを作成する（ステップＳ１３）。より具体的には、プロセッサ１０１は最初に、メインメモリ１０２上のオブジェクトＢ₁ 〜Ｂ_N の中から、ステップＳ８で得た現在の操舵角α_i に割り当てられているオブジェクトＢ_q を選択する。ここで、ｑは、１からＮのいずれかの自然数である。次に、プロセッサ１０１は、オブジェクトＢ_q を構成する座標列から少なくとも４個の座標値を選択する。この時、オブジェクトＢ_q の開始線Ｌ_ST（図７参照）を示す２個の座標値を必ず含む。
【００５１】
ステップＳ１３の次に、図５に示す表示画像Ｉ_DPY が作成・表示される（ステップＳ１４）。ステップＳ１４をより具体的に説明すると、まず、ステップＳ１２で作成された最適経路ＬＴを構成する車両座標系の座標列が、画像座標系の座標列に変換される。さらに、ステップＳ１３で作成された予想走行軌跡ＥＴを構成する車両座標系の座標列が、画像座標系の座標列に変換される。なお、このような座標変換については、例えば、国際公開ＷＯ００−０７３７３号公報に開示されているので、ここではその詳細な説明を省略する。以上の座標変換された最適経路ＬＴおよび予想走行軌跡ＥＴが、ステップＳ７でフレームメモリに格納された撮影画像Ｉ_CPT に重畳され、これによって、現在時刻ｔ_CPでの表示画像Ｉ_DPY が完成する。次に、プロセッサ１０１の制御下で、完成した表示画像Ｉ_DPY が表示装置１６に転送され、表示装置１６は、受信表示画像Ｉ_DPY を表示する。
【００５２】
次に、プロセッサ１０１は、入力装置１１から、上述の終了指示Ｄ_TDが到着しているか否かを判断する（ステップＳ１５）。終了指示Ｄ_TDが到着済であれば、プロセッサ１０１は、車両Ｍが停止位置Ｐ_SPに到達したと見なして、画像表示処理を終了し、そうでなければ、次の表示画像Ｉ_DPY を作成するために、ステップＳ７に戻る。
【００５３】
ここで、図１４は、基準時刻ｔ_REF から終了指示Ｄ_TDの到着時までに、表示装置１６で表示される表示画像Ｉ_d がどのように遷移するかを示す模式図である。図１４には、４フレーム分の表示画像Ｉ_DPY が示されている。最上段の表示画像Ｉ_d は、運転支援装置１が基準時刻ｔ_REF に上述の処理を実行することで表示される。また、その下段の表示画像Ｉ_DPY は、時刻（ｔ_REF ＋Δｔ）に表示される。さらに、時刻（ｔ_REF ＋Δｔ）および（ｔ_REF ＋２×Δｔ）に表示される表示画像Ｉ_DPY が示されている。また、図１４の最下段には、時刻（ｔ_REF ＋３×Δｔ）に表示され、終了指示Ｄ_TDの到着直前の表示画像Ｉ_DPY が示されている。以上の表示画像Ｉ_DPY の時間に対する変化を見れば分かるように、終了指示Ｄ_TDの到着時に近づくに連れて、表示装置１６の画面上において、最適軌跡ＬＴの形状は、車両Ｍの動きに応じて変化し、より具体的には、車両Ｍの停止位置Ｐ_SPに向かって縮んでいく最適軌跡ＬＴが表示される。また、車両Ｍは、縮んでいく最適軌跡ＬＴに追従するように表示される。これによって、ドライバは、従来よりも、駐車スペースにおける停止位置Ｐ_SPに車両Ｍが正しく向かっているかどうかを確認しやすくなる。
【００５４】
さらに、表示画像Ｉ_d には、最適軌跡ＬＴだけでなく予想走行軌跡ＥＴも合成される。もし、ドライバが適切なハンドル操作を行い、車両Ｍが正しく停止位置Ｐ_SPに向かっている場合には、図１４に示すように、表示装置１６の画面上において、予想走行軌跡ＥＴは、最適軌跡ＬＴ上を動くように表示される。しかしながら、もし、ドライバが不適切なハンドル操作を行った場合には、図１５に示す表示画像Ｉ_DPY のように、予想走行軌跡ＥＴは、最適軌跡ＬＴから外れてしまう。これによって、ドライバは、瞬時に、ハンドル操作の誤りに気づくことが可能となり、さらに使い勝手の良い運転支援装置１を提供することが可能になる。
【００５５】
また、以上の実施形態では、最適軌跡ＬＴおよび予想走行軌跡ＥＴの双方が撮影画像Ｉ_CPT に重畳されるとして説明した。しかし、本願で設定された課題を解決するには、少なくとも、最適軌跡ＬＴが重畳されれば良い。また、撮像装置１２のレンズに生じる歪みを補正された撮影画像Ｉ_CPT に、最適軌跡ＬＴおよび予想走行軌跡ＥＴの双方が重畳されても良い。
【００５６】
なお、以上の実施形態では、ドライバは、初期表示画像Ｉ_D0を見ながら、この終端線Ｌ_TMが停止位置Ｐ_SPに合うように、車両Ｍを移動させるとして説明した。その結果、最適軌跡ＬＴは、車両Ｍの現在位置Ｐ_CPからその停止位置Ｐ_SPまでを表すようにしていた。しかし、これに限らず、運転支援装置１は、プログラムＣ₁ の実行を開始直後、予め定められたオブジェクトＢ_j を最適経路ＬＴとして選択してもよい。この場合、初期表示画像Ｉ_D0において、オブジェクトＢ_j （つまり、最適経路ＬＴ）の終端線Ｌ_TMは、大抵の場合、停止位置Ｐ_SPを指示しない。このような最適経路ＬＴであっても、ドライバは、停止位置Ｐ_SPに至る途中までの最適経路が分かるという技術的効果を奏する。つまり、最適経路ＬＴは、少なくとも、車両Ｍの現在位置Ｐ_CPからの最適経路を表せば良い。
【００５７】
また、以上の実施形態では、撮影画像Ｉ_CPT は、撮像装置１２の位置を視点として車両Ｍの後方を見た画像であった。しかし、これに限らず、撮影画像Ｉ_CPT に対して視点変換処理を行って、撮像装置１２の位置以外の視点（例えば、車両Ｍの上方）から車両Ｍの後方を見た画像（以下、視点変換画像と称する）を作成し、プロセッサ１０１は、作成した視点変換画像に、最適軌跡ＬＴおよび／または予想走行軌跡ＥＴを重畳して、表示画像（以下、視点変換表示画像と称する）を作成しても良い。さらに、プロセッサ１０１は、前述の表示画像Ｉ_DPY および上述の視点変換表示画像を画像合成して、両者を同時に表示装置１６に表示させても良い。
【００５８】
また、以上の実施形態では、撮像装置１２は１台として説明したが、複数台であっても良い。この場合、プロセッサ１０１は、複数台からの撮影画像Ｉ_CPT を１枚の画像につなぎ合わせた後に、最適軌跡ＬＴおよび／または予想走行軌跡ＥＴを重畳して、表示画像を作成する。また、撮像装置１２は必ずしも、車両Ｍの両側面から等距離に固定されるなくともよく、縦中心面Ｓ_C から車両Ｍの左右方向にずれた位置に固定されても良い。なお、このように撮像装置１２が設置されたとしても、上述の視点変換処理により、運転支援装置１は、車両Ｍの中心から見たときの表示画像Ｉ_DPY を作成することができる。
【００５９】
また、以上の実施形態では、撮影画像Ｉ_CPT を参照すれば明らかなように、左右方向に並ぶ２台の車両の間の駐車スペースの右斜め前方から、車両Ｍを駐車するような状況を例に取り上げて説明した。しかし、このような例だけでなく、駐車スペースの左斜め前方から駐車するような状況にも、本画像作成装置１０は簡単に応用できる。さらに、前後方向に並ぶ２台の車両の間に駐車する場合にも応用することができる。ただし、この場合には、車両Ｍは、図１６に示すように、、Ｓ字を描くように駐車スペースに向かって移動するので、このような形状を表すオブジェクトＢ_S を予め準備する必要がある。
【００６０】
また、以上の実施形態では、最適軌跡ＬＴおよび予想走行軌跡ＥＴは平面的な図形で表現されていたが、これに限らず、単なる線で表現されても良い。
【００６１】
「第２の実施形態」
ところで、第１の実施形態では、図９のステップＳ１０において、プロセッサ１０１は、ヨーレートセンサ１５から第１のヨーレートω₁ を受信していた。しかし、第２の実施形態では、第１のヨーレートω₁ を算出できる運転支援装置２を提供することを目的とする。
【００６２】
図１７は、第２の実施形態に係る画像作成装置２０を組み込んだ運転支援装置２のハードウェア構成を示すブロック図である。図１７において、運転支援装置２は、図１に示す運転支援装置１と比較すると、ヨーレートセンサ１５が不要である点と、プログラムメモリ１０３にソフトウェアＳ₁ の代わりに、図１７に示すようなソフトウェアＳ₂ が格納される点で相違する。それ以外に相違点は無いので、図１７において、図１の構成に相当するものには、同一の参照符号を付けて、その説明を省略する。また、ソフトウェアＳ₂ は、図１８に示すように、ソフトウェアＳ₁ （図６参照）と比較すると、プログラムＣ₁ の代わりに、コンピュータプログラム（以下、単にプログラムと称する）Ｃ₂ を含む点で相違する。オブジェクトＢについては、第１の実施形態と同様であるため、本実施形態では説明を省略する。プログラムＣ₂ は、本運転支援装置２の動作を規定する。
【００６３】
次に、以上の構成を有する運転支援装置２の動作を説明する。運転支援装置２の電源投入後、プロセッサ１０１はまず、プログラムメモリ１０３からソフトウェアＳ₂ をメインメモリ１０２に読み出す。プロセッサ１０１は、入力装置１１からの開始指示Ｄ_SDの受信に応答して、メインメモリ１０２上のプログラムＣ₂ の実行、つまり画像表示処理を開始する。
【００６４】
ここで、図１９および図２０は、プログラムＣ₂ に記述されている運転支援装置２の動作手順を示すフローチャートである。図１９および図２０のフローチャートは、図８および図９のフローチャートと比較すると、ステップＳ１０がステップＳ２１に代わる点で相違する。それ以外に、両フローチャートの間に相違点はないので、図１９および図２０において、図８および図９のステップに相当するものには、同じステップ番号を付け、それらの説明を省略する。
【００６５】
以下、ステップＳ１０の具体的な説明の前に、そこで必要となる各パラメータおよび理論を、図面を参照して説明する。まず、図２１には、その質量がｍの車両Ｍが示されている。また、車両Ｍの重心位置Ｐ_BYC から、その両前輪の回転中心同士を結ぶ線分までの距離をＤ_f 、また、その両後輪の回転中心同士を結ぶ線分までの距離をＤ_r とおく。また、車両ＭのホイールベースをＬとすると、Ｌ＝（Ｄ_f ＋Ｄ_r ）である。さらに、図２１には示していないが、車両Ｍのヨーイング慣性モーメントをＩ_m 、車両Ｍの前輪コーナリングパワーをＫ_f 、その後輪コーナリングパワーをＫ_r とする。以上の質量ｍ、ヨーイング慣性モーメントＩ_m 、ホイールベースＬ、距離Ｄ_f 、距離Ｄ_r 、前輪コーナリングパワーＫ_f 、および後輪コーナリングパワーＫ_r の値は、車両Ｍに固有で既知の値である。
【００６６】
また、図２１において、車両Ｍの前輪の実舵角をεとおく。ここで、実舵角εは、車両Ｍのハンドル操舵角α_i に比例する値であり、次式（６）で算出することができる。
ε＝Ｂ×α_i …（６）
ここで、Ｂは、車両Ｍに固有で既知の定数である。
さらに、図２１には、車両Ｍの進行方向（速度Ｖのベクトル）と、第１のヨーレートω₁ および横滑り角δとが図示されている。しかし、これらについては、第１の実施形態で説明しているので、ここではその説明を省略する。
【００６７】
以上のパラメータを有する車両Ｍの運動方程式は次式（７）で表される。
【数３】

また、車両Ｍの重心位置Ｐ_BYC の鉛直軸周りのヨーイング運動方程式は、次式（８）で表される。
【数４】

上式（７）および（８）を整理すると、次式（９）および（１０）が得られる。
【数５】

【００６８】
さらに、上式（９）および（１０）をラプラス変換すると、車両Ｍの運動方程式およびヨーイング運動方程式は、次式（１１）のように表現される。
【数６】

ここで、ｓはラプラス演算子である。
【００６９】
さて、図２０のステップＳ２１において、プロセッサ１０１は、ステップＳ８およびＳ９で受信した操舵角α_i および速度Ｖを使って、車両Ｍの移動量ＴＡを求める。より具体的には、プロセッサ１０１は、受信した操舵角α_i を、前式（６）に代入して、実舵角εを算出する。それゆえ、上式（１１）において、未知数は、第１のヨーレートω₁ のみとなる。なお、δは横滑り角であるが、駐車時のように車両Ｍが低速走行している場合には、０とみなせるので既知の値である。実舵角εの算出後、プロセッサ１０１は、受信した速度Ｖおよび算出した実舵角εを使って、上式（１１）を解き、第１のヨーレートω₁ を算出する（ステップＳ２１）。
【００７０】
次のステップＳ１１において、プロセッサ１０１はまず、ステップＳ２１で算出した第１のヨーレートω₁ を前式（３）に代入して、第２のヨーレートω₂ を算出する。以降、プロセッサ１０１は、第１の実施形態で説明したようにして、移動量ＴＡ（ｘ_CP−ｘ_CP0 ，ｙ_CP−ｙ_CP0 ）を算出する。
以上のように、本実施形態によれば、運転支援装置１のようにヨーレートセンサ１５が不要になるので、本運転支援装置２の構成を簡素化できるという技術的効果を得ることができる。
【００７１】
「第３の実施形態」
また、第１の実施形態では、図９のステップＳ９において、プロセッサ１０１は、車速センサ１４から速度Ｖを受信していた。しかし、第３の実施形態では、速度Ｖを算出できる運転支援装置３を提供することを目的とする。
【００７２】
図２２は、第２の実施形態に係る画像作成装置３０を組み込んだ運転支援装置３のハードウェア構成を示すブロック図である。図２２において、運転支援装置３は、図１に示す運転支援装置１と比較すると、車速センサ１４が不要である点と、プログラムメモリ１０３にソフトウェアＳ₁ の代わりに、図２３に示すようなソフトウェアＳ₃ が格納される点である。それ以外に相違点は無いので、図２２において、図１の構成に相当するものには、同一の参照符号を付けて、その説明を省略する。また、図２３において、ソフトウェアＳ₃ は、ソフトウェアＳ₁ （図６参照）と比較すると、プログラムＣ₁ の代わりに、コンピュータプログラム（以下、単にプログラムと称する）Ｃ₃ を含む点で相違する。オブジェクトＢについては、第１の実施形態と同様であるため、本実施形態では説明を省略する。プログラムＣ₃ は、本運転支援装置３の動作を規定する。
【００７３】
次に、以上の構成を有する運転支援装置３の動作を説明する。運転支援装置３の電源投入後、プロセッサ１０１はまず、プログラムメモリ１０３からソフトウェアＳ₃ をメインメモリ１０２に読み出す。プロセッサ１０１は、入力装置１１からの開始指示Ｄ_SDの受信に応答して、メインメモリ１０２上のプログラムＣ₃ の実行、つまり画像表示処理を開始する。
【００７４】
ここで、図２４および図２５は、プログラムＣ₃ に記述されている運転支援装置３の動作手順を示すフローチャートである。図２４および図２５のフローチャートは、図８および図９のフローチャートと比較すると、ステップＳ９がステップＳ３１に代わる点で相違する。それ以外に、両フローチャートの間に相違点はないので、図２４および図２５において、図８および図９のステップに相当するものには、同じステップ番号を付け、それらの説明を省略する。
【００７５】
以下、ステップＳ３１の具体的な説明の前に、そこで必要となる空間フィルタリングによる車速の測定について説明する。なお、空間フィルタリングについては、例えば、空間フィルタとその応用〔Ｉ〕（計測自動制御学会誌「計測と制御」Vol.19,No.4 ）に詳しく記載されている。図２６は、空間フィルタリングの基本原理を示す模式図である。図２６には、スリット列４１と、点光源４２と、光学系４３とが示されている。スリット列４１は、同一平面Ｓ_SLT 上に一定ピッチｐで同一方向に配列された複数のスリットである。また、点光源４２は、スリット列４１に対し相対速度Ｖ’で、スリット列４１上をその配列方向に移動しながら、スリット列４１に向けて光を出射する。光学系４３は、スリット列４１および点光源４２の間に置かれ、点光源４２からの光を通過させる。光学系４３の通過光は、スリット列４１上で焦点を結ぶ。このようにして、スリット列４１上には、スポット光Ｌ_SPT が投影される。
【００７６】
また、図２６に示すように、このスリット列４１を間において点光源４２を見るような位置で、上述のスポット光Ｌ_SPT を観測した場合、スリット列４１を通過中のスポット光Ｌ_SPT の光強度は、スリットの配列方向の変位ｐ毎に、１つのパルスが表れる信号になる。このような信号（パルス）の周期Ｔ_CYL は、ｐ／Ｖ’となる。また、信号の周波数ｆ_SPT はＶ’／ｐとなり、相対速度Ｖ’に比例することが分かる。つまり、スポット光Ｌ_SPT の相対速度Ｖ’は時間的に変動する場合、その時間変動に応じて、周波数ｆ_SPT も変化する。しかし、スポット光Ｌ_SPT が平面Ｓ_SLT 上を変位ｐだけ移動する度に、光信号には１つのパルスが現れるという性質は不変である。
【００７７】
また、上述の撮影画像Ｉ_CPT のような一般的な光学的パターンには、多くの光強度を有する多数の点光源がランダムに配置されていると考えることができる。また、光学的パターンに含まれる多数の点光源は、互いの位置関係を変えることなく、一定方向に同時に並行移動していると考えることができる。このような光学的パターンを、図２６における点光源４２と置き換えて、点光源と同様に移動させた場合、スリット列４１を間において点光源４２を見るような位置では、互いに同一周波数ｆ_SPT を有するが、その位相および振幅が相違する多数の信号を加算（合成）した信号が観測される。以下、観測された信号を、狭帯域ランダム信号と称する。この狭帯域ランダム信号の平均的な周波数ｆ_AVE は、上述のＶ’／ｐであり、その位相および振幅は、時間的に不規則かつゆっくりと変動する。
【００７８】
次に、以上のような波形を有する狭帯域ランダム信号から、光学的パターン自体の相対速度Ｖ’_PTN の算出方法を説明する。図２７は、相対速度Ｖ’_PTN の算出に使用されるモデルの模式図である。図２７には、光学パターン５１と、空間フィルタ５２と、光学系５３と、光検出器５４とが示されている。光学パターン５１は、ランダムな光強度分布ｆ（ｘ，ｙ）を有する。空間フィルタ５２は、光学パターン５１の直上に密接して配置される。また、空間フィルタ５２は、２次元直交座標系における点Ｐ_FLT を原点として、ｘ軸方向の長さがＸ_FLT で、ｙ軸方向の長さがＹ_FLT の矩形形状を有しており、予め定められた透過率分布ｈ（ｘ，ｙ）を持つ空間荷重関数である。以上の空間フィルタ５２は、光学パターン５１から発する光を通過させる。光学系５３は、空間フィルタ５２を通過した光を集束する。光検出器５４は、光学系５３により集められた光を電気に変換して、瞬時出力ｇ（ｘ₀ ，ｙ₀ ）を生成する。ここで、瞬時出力ｇ（ｘ₀ ，ｙ₀ ）は、比例定数を無視した場合、次式（１２）で表される。
【００７９】
【数７】

ここで、ｘ₀ およびｙ₀ は、空間フィルタ５２の原点Ｐ_FLT 上に位置する光学パターン５１のｘ座標値およびｙ座標値である。
【００８０】
以上のようなモデルにおいて、光学パターン５１がｘ軸方向に一定速度Ｖ’_PTN で平行移動している時には、ｘ₀ およびｙ₀ は、次式（１３）および（１４）で表される。
ｘ₀ ＝Ｖ’_PTN ・ｔ＋ｃ₁ …（１３）
ｙ₀ ＝ｃ₂ …（１４）
ここで、ｔは時間であり、ｃ₁ およびｃ₂ は定数である。
【００８１】
今、ｙ₀ を固定し、ｇ（ｘ₀ ，ｙ₀ ）を変位ｘ₀ の関数と考えると、ｘ軸方向の空間領域でのパワースペクトル密度関数Ψ（μ）は、次式（１５）のように表される。
【数８】

ここで、μおよびνは、ｘ軸方向およびｙ軸方向の空間周波数である。また、Ｈ（μ，ν）は、次式（１６）で示される。また、Φ（μ，ν）は、ｆ（ｘ，ｙ）に関する空間領域での２次元的パワースペクトル密度関数である。
【数９】

【００８２】
また、上式（１５）は、透過率分布ｈ（ｘ，ｙ）がｙ軸方向に一定であると仮定すると、近似的に次式（１７）のように表される。
【数１０】

ここで、Ｈ（μ）は、次式（１８）で示される。
【数１１】

【００８３】
ここで、光学パターン５１の速度Ｖ’_PTN による影響を考慮するために、瞬時出力ｇ（ｘ₀ ，ｙ₀ ）を時間ｔの関数ｇ（ｘ₀ ，ｙ₀ ，ｔ）とすると、時間領域でのパワースペクトル密度関数Ω（ｆ）は、次式（１９）で表される。
【数１２】

ここで、ｆは、時間的周波数である。
【００８４】
上式（１５）〜（１９）において、｜Ｈ（μ）｜² が、μ＝μ₀ のみを選択する特性を持つと仮定すると、Φ（μ₀ ，０）＝０でない限り、Ψ（μ）は、μ＝μ₀ で急峻なスペクトルを持つ。したがって、Ω（ｆ）にも、ｆ＝Ｖμ₀ のところに際だったスペクトルが現れる。したがって、速度Ｖ’_PTN に比例する周波数の正弦波信号が瞬時出力ｇ（ｘ₀ ，ｙ₀ ，ｔ）として得られることになり、この正弦波信号に対して、フーリエ変換またはウェーブレット変換に代表される周波数測定を行うことにより、速度Ｖ’_PTN を検出することが可能になる。
【００８５】
以上の空間フィルタリングを運転支援装置３に応用するために、図２８に示すように、メインメモリ１０２における撮影画像Ｉ_CPT の記憶領域には、仮想的なスリット列６１が予め設定されている。スリット列６１は、メインメモリ１０２のメモリ空間に、一定ピッチｐで同一方向に配列された複数のスリットであり、撮影画像Ｉ_CPT において路面Ｓ_R が映っていると想定されるところに配置される。各スリットの位置および形状は、第１の実施形態で説明した画像座標系の座標値で指定される。プロセッサ１０１は、ステップＳ３１において、メインメモリ１０２内の撮影画像Ｉ_CPT においてスリット列６１に含まれる複数の画素を、上述の光学パターン５１とみなし、この光学パターン５１に対して空間フィルタリングを実行する。
【００８６】
より具体的には、一般的に、撮影画像Ｉ_CPT は、白黒の場合には、それを構成する各画素の輝度値を示すデータを含んでいる。また、カラーの場合、撮影画像Ｉ_CPT は、各画素毎に、光の３原色の輝度値を示すデータを含んでいるが、周知の方法で、白黒の輝度値に変換することが可能である。プロセッサ１０１はまず、今回格納された撮影画像Ｉ_CPT を使って、そのスリット列６１に含まれる全ての画素の白黒の輝度値を加算する。それによって、プロセッサ１０１は、輝度の合計値を求め、メインメモリ１０２上に蓄積する。ここで、メインメモリ１０２には、今回の合計値を含む、過去数フレーム分の撮影画像Ｉ_CPT から求められた合計値を格納するための記録領域が予約されている。従って、メインメモリ１０２には、図２９（ａ）に示すような時間軸上での合計値の変化を示すデータが格納されることになる。次に、プロセッサ１０１は、時間軸上で表された合計値の変化を、図２９（ｂ）に示すような周波数軸上のものに変換した後、得られた周波数軸上の合計値から、ピーク値を検出する。さらに、プロセッサ１０１は、検出したピーク値に対応する周波数成分ｆを検出する。その後、プロセッサ１０１は、検出した周波数成分ｆと、上述のピッチｐとから、光学パターン５１、つまり路面Ｓ_R の車両Ｍに対する相対速度Ｖ’_PTN （＝ｐ／ｆ）を算出する。プロセッサ１０１は、このようにして得られた相対速度Ｖ’_PTN の極性を反転させ、車両Ｍの速度Ｖを導出する（ステップＳ３１）。
【００８７】
以上のように、本実施形態によれば、運転支援装置１のように車速センサ１４が不要になるので、運転支援装置３の構成を簡素化できるという技術的効果を得ることができる。
【００８８】
なお、以上の第１〜第３の実施形態では、プログラムＣ₁ 〜Ｃ₃ は、プログラムメモリ１０３に格納されていた。しかし、これに限らず、プログラムＣ₁ 〜Ｃ₃ は、ＣＤ−ＲＯＭに代表される記録媒体に記録された状態で頒布されてもよいし、インターネットに代表される通信ネットワークを通じて頒布されてもよい。
【００８９】
また、現在の最適経路ＬＴの導出方法には、上述の実施形態で説明したもの以外に、周知のアッカーマンモデルを使う方法もある。アッカーマンモデルでは、最適経路ＬＴは、操舵角α_i および速度Ｖに基づいて導出される。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る運転支援装置１のハードウェア構成を示すブロック図である。
【図２】図１の撮像装置１２の固定位置を示す模式図である。
【図３】図１の撮像装置１２により生成される撮影画像Ｉ_CPT の一例を示す模式図である。
【図４】図１のヨーレートセンサ１５で検出される第１のヨーレートω₁ を説明するための模式図である。
【図５】図１のプロセッサ１０１により作成される表示画像Ｉ_DPY の一例を示す模式図である。
【図６】図１のプログラムメモリ１０３に格納されるソフトウェアＳ₁ の詳細な構成を示す模式図である。
【図７】図６に示すオブジェクトＢ_N を説明するための模式図である。
【図８】図１の運転支援装置１の動作手順を示すフローチャートの前半部分である。
【図９】図１の運転支援装置１の動作手順を示すフローチャートの後半部分である。
【図１０】図８のステップＳ３で確定通知Ｉ_NTの到着前に作成される初期表示画像Ｉ_D0を示す模式図である。
【図１１】図８のステップＳ５の時点で表示されている初期表示画像Ｉ_D0を示す模式図である。
【図１２】図９のステップＳ１１において算出される第２のヨーレートω₂ を説明するための模式図である。
【図１３】図９のステップＳ１２におけるプロセッサ１０１の処理内容を説明するための模式図である。
【図１４】図１の表示装置１６の表示画面の時間に対する変化を示す模式図である。
【図１５】ドライバがハンドル操作を誤った時、図１の表示装置１６に表示される表示画像Ｉ_DPY を示す模式図である。
【図１６】図６に示すオブジェクトＢ_N をの代替例であるオブジェクトＢ_S を説明するための模式図である。
【図１７】本発明の第２の実施形態に係る運転支援装置２のハードウェア構成を示すブロック図である。
【図１８】図１７のプログラムメモリ１０３に格納されるソフトウェアＳ₂ の詳細な構成を示す模式図である。
【図１９】図１７の運転支援装置２の動作手順を示すフローチャートの前半部分である。
【図２０】図１７の運転支援装置２の動作手順を示すフローチャートの後半部分である。
【図２１】図２０のステップＳ２１で必要となる車両Ｍのパラメータを示す模式図である。
【図２２】本発明の第３の実施形態に係る運転支援装置３のハードウェア構成を示すブロック図である。
【図２３】図２２のプログラムメモリ１０３に格納されるソフトウェアＳ₃ の詳細な構成を示す模式図である。
【図２４】図２２の運転支援装置３の動作手順を示すフローチャートの前半部分である。
【図２５】図２２の運転支援装置３の動作手順を示すフローチャートの後半部分である。
【図２６】図２２の運転支援装置３に応用される空間フィルタリングの基本概念を示す模式図である。
【図２７】図２６の空間フィルタリングを使って、空間パターン５１の相対速度Ｖ’_PTN の算出に使用されるモデルの模式図である。
【図２８】図２２の運転支援装置３に予め設定されるスリット列６１を示す模式図である。
【図２９】図２５のステップＳ３１における相対速度Ｖ’_PTN の検出方法を説明するための模式図である。
【図３０】従来のモニター装置において表示される４フレーム分の表示画像Ｉ_d1〜Ｉ_d4を示す模式図である。
【符号の説明】
１，２，３…運転支援装置
１０，２０，３０…画像作成装置
１０１…プロセッサ
１０２…メインメモリ
１０３…プログラムメモリ
Ｓ₁ ，Ｓ₂ ，Ｓ₃ …ソフトウェア
Ｃ₁ ，Ｃ₂ ，Ｃ₃ …コンピュータプログラム
１１…入力装置
１１１，１１２、１１３…操作ボタン
１２…撮像装置
１３…操舵角センサ
１４…車速センサ
１５…ヨーレートセンサ
１６…表示装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image creating apparatus, and more particularly to an image creating apparatus that creates an image for driving support of a vehicle based on a captured image obtained from an in-vehicle imaging device.
[0002]
[Prior art]
Conventionally, the above-described image creating apparatuses have been actively researched and developed. As such an image creating apparatus, in the section of the prior art, a monitor apparatus disclosed in Japanese Patent Application Laid-Open No. 59-114139 will be described. In this monitor device, an in-vehicle camera creates an image (hereinafter referred to as a captured image) obtained by capturing a scene behind the host vehicle. Based on the steering angle from the steering angle sensor, the CPU creates a figure (hereinafter simply referred to as an “anticipated traveling locus”) indicating an expected traveling locus that the vehicle is supposed to follow. The CPU superimposes the created predicted travel locus on the captured image to create a display image. The display device receives and displays the above display image.
[0003]
Now, assume that the driver actually puts the vehicle in the parking space. Here, FIG. 30 shows the display image I for four frames displayed on the display device from the start of parking until the end of parking._d1~ I_d4It is a schematic diagram which shows. In FIG. 30, display image I_d1At the start of parking (time t_d1Displayed on the display device. Furthermore, the display image I_d2Is the time t_d1Later time t_d2Display image I_d3Is the time t_d3Later time t_d3Is displayed. The display image I_d4Is the time t_d3Later andSelfTime t when vehicle and parking space are aligned_d4Is displayed. Display image I_d1~ I_d4The above-mentioned predicted travel locus ET is superimposed on any of the above. In addition, the predicted travel locus ET is the time t_d1~ T_d4The display image I is determined from the steering angle of the host vehicle at_d1~ I_d4The vehicle M has a predetermined length from the vehicle M. Display image I_d1~ I_d4By looking at, the driver can check how the vehicle will proceed with the current steering wheel operation.
[0004]
[Problems to be solved by the invention]
Next, the problems that the above monitor device has will be described. At the time of parking, most drivers first move their vehicle to a place (hereinafter referred to as an initial position) where it is easy to enter the parking space, and then move the vehicle toward the parking space. During the movement of the host vehicle, the driver is concerned whether the host vehicle is correctly heading to the stop position in the parking space. However, the conventional display image (see FIG. 30) shows only the trajectory that the host vehicle is supposed to follow by the current steering wheel operation. Therefore, if the steering wheel operation is mistaken, the predicted traveling locus will deviate from the parking space. In such a case, there is a problem that it is difficult for the driver to understand how much the steering operation is corrected and how the host vehicle goes to the stop position.
[0005]
Therefore, an object of the present invention is to provide an image creation device that creates an image that makes it easy to understand whether or not the host vehicle is correctly heading toward a stop position.
[0006]
[Means for Solving the Problems and Effects of the Invention]
  The first aspect of the present invention is directed to an image creating apparatus for driving assistance of a vehicle. The present invention provides an imaging device installed in a vehicle, a steering angle sensor that detects the steering angle of the vehicle, an image captured by the imaging device, and a display image based on the steering angle detected by the steering angle sensor. A processor to create, a main memory assigned to a plurality of steering angles, and stores a plurality of objects that are graphic data for specifying the shape of a trajectory that the vehicle is supposed to follow while maintaining the steering angles; A display device for displaying a display image created by the processor;Accept operation input from vehicle driverAn input device, and a processorAn object assigned to a predetermined steering angle is selected from the main memory, and a scene represented by an image captured by the imaging device is displayed.An initial display image is created by superimposing, the display device displays the initial display image, and the input deviceHowever, due to the movement of the vehicleObject displayed in the initial display imageButEnter information that indicates the optimal trajectory that represents the optimal trajectory from the current position of the vehicle to the stop position.From the driverAcceptanceWhenThe processor determines the object displayed in the initial display image as the optimum locus based on the information received by the input device, and is stored in the main memory based on the steering angle detected by the steering angle sensor. Using the object, an expected traveling trajectory expected to be followed by the vehicle is created, and a display image in which the optimum trajectory and the predicted traveling trajectory are superimposed on a scene is created in the main memory.
[0007]
  In this way, since an optimal trajectory and an expected travel trajectory can be created using an object prepared in advance, an image can be created quickly.
[0008]
  Further, it is preferable that the processor transfers the display image created by being superimposed on the main memory to a display device connected to be communicable with the processor, and the display device displays the received display image from the main memory.
[0009]
  The second aspect of the present invention is directed to an image creation method for driving support of a vehicle. The present inventionA plurality of objects, which are graphic data that are assigned to a plurality of steering angles and specify the shape of a trajectory that the vehicle is supposed to follow while maintaining the steering angles, are stored in the main memory.A steering angle detection step for detecting a steering angle of the vehicle, an image captured by the imaging device, a display image generation step for generating a display image based on the steering angle detected in the steering angle detection step, and a display image generation A display step for displaying the display image created in the step;An object assigned to a predetermined steering angle is selected from the main memory, and a scene represented by an image captured by the imaging device is displayed.An initial display image creation step for creating an initial display image by superimposing; an initial display image display step for displaying an initial display image;By moving the vehicleObject displayed in the initial display imageButEnter information that indicates the optimal trajectory that represents the optimal trajectory from the current position of the vehicle to the stop position.From the vehicle driverAn optimal trajectory input step, an optimal trajectory determination step for determining an object displayed in the initial display image as the optimal trajectory based on the information received in the optimal trajectory input step, and a steering angle detection step. Based on the steering angle, MeUsing the object stored in the in-memory, an expected traveling locus creating step for creating an expected traveling locus that the vehicle is expected to follow from now on, and a display image in which the optimum locus and the predicted traveling locus are superimposed on the scene are stored in the main memory. A creation step for creating.
[0010]
  In this way, since an optimal trajectory and an expected travel trajectory can be created using an object prepared in advance, an image can be created quickly.
[0011]
  And a transfer step of transferring a display image created by being superimposed on the main memory to a display device communicably connected to the main memory, and a received display image display step of displaying a received display image from the main memory. Is preferred.
[0012]
  The third aspect of the present invention is directed to an image creation program executed by a computer of an image creation device for driving support of a vehicle. The present inventionA plurality of objects, which are graphic data that are assigned to a plurality of steering angles and specify the shape of a trajectory that the vehicle is supposed to follow while maintaining the steering angles, are stored in the main memory.A steering angle detection step for detecting a steering angle of the vehicle in the computer; an image captured by the imaging device; and a display image creation step for creating a display image based on the steering angle detected in the steering angle detection step; A display step for displaying the display image created in the display image creation step;An object assigned to a predetermined steering angle is selected from the main memory, and a scene represented by an image captured by the imaging device is displayed.An initial display image creation step for creating an initial display image by superimposing; an initial display image display step for displaying an initial display image;By moving the vehicleObject displayed in the initial display imageButEnter information that indicates the optimal trajectory that represents the optimal trajectory from the current position of the vehicle to the stop position.From the driverAn optimal trajectory input step, an optimal trajectory determination step for determining an object displayed in the initial display image as an optimal trajectory based on information received in the optimal trajectory input step, and steering detected in the steering angle detection step Based on corner, MeUsing the object stored in the in-memory, an expected traveling locus creating step for creating an expected traveling locus that the vehicle is expected to follow from now on, and a display image in which the optimum locus and the predicted traveling locus are superimposed on the scene are stored in the main memory. Let the creation step to create and run.
[0013]
  In this way, since an optimal trajectory and an expected travel trajectory can be created using an object prepared in advance, an image can be created quickly.
[0014]
  In addition, a transfer step of transferring a display image created by superimposing on the main memory to a display device connected to be communicable with the main memory and a reception display image display step of displaying a reception display image from the main memory are executed. It is preferable.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
“First Embodiment”
FIG. 1 is a block diagram showing a hardware configuration of a driving support apparatus 1 incorporating an image creating apparatus 10 according to the first embodiment of the present invention. In FIG. 1, the image creating apparatus 10 includes at least a processor 101, a main memory 102, and a program memory 103. The driving support device 1 is mounted on a vehicle M (see FIG. 2), and in addition to the image creation device 10, an input device 11, at least one imaging device 12, a steering angle sensor 13, a vehicle speed sensor 14, and a yaw rate. A sensor 15 and a display device 16 are provided.
[0026]
The input device 11 is operated by a driver of the vehicle M, and is configured by three operation buttons 111 to 113 in the present embodiment. A start function for image display processing (see FIGS. 8 and 9) is assigned to the operation button 111. The driver operates the operation button 111 when entering the vehicle M into the parking space from diagonally forward to the right. In response to this operation, the input device 11 receives information (hereinafter referred to as a start instruction) D for instructing the start of the image display process._SDIs output to the processor 101. The operation button 112 is assigned a function for determining the optimum locus LT (see FIG. 5). When the driver operates this operation button 112, the input device 11 provides information for notifying that the optimum trajectory LT is confirmed (hereinafter referred to as a confirmation notice) D._NTIs output to the processor 101. The operation button 113 is assigned with an image display processing end function. The driver operates the operation button 113 when the vehicle M is completely in the parking space. In response to this operation, the input device 11 provides information for instructing the end of the image display process (hereinafter referred to as an end instruction) D._TDIs output to the processor 101.
[0027]
The imaging device 12 in FIG. 1 is fixed to the rear end of the vehicle M at an equal distance from both side surfaces of the vehicle M as shown in FIG. More specifically, the optical axis OA of the imaging device 12 is the longitudinal center plane S._CIt extends toward the rear of the vehicle M, and the optical axis OA is the road surface S._RThe imaging device 12 is fixed so that it intersects with. Here, the longitudinal center plane S_CIs a vertical plane that bisects a line segment connecting the rotation centers of both front wheels (or both rear wheels) of the vehicle M. The imaging device 12 fixed as described above captures a scene in the field of view behind the vehicle M, and a captured image I as shown in FIG._CPTIs generated. Here, the captured image I_CPTIt is preferable that the rear end of the vehicle M is reflected.
[0028]
The steering angle sensor 13 in FIG. 1 detects an angle (that is, a steering angle) by which a handle attached to the vehicle M is rotated from a predetermined reference position, and a steering angle α indicating a detection result._iIs sent to the processor 101. Here, i is any natural number from 1 to N. N is determined according to the design requirements of the driving support device 1, but is assumed to be an odd number in this embodiment for convenience. The reference position described above is preferably the position of the steering wheel when the vehicle M is traveling straight ahead. In the present embodiment, for the sake of convenience, the steering angle α₁= -Α_L , Α₂= -Α_L + Δα, α_Three= -Α_L + 2 × Δα, ..., α_{(N-1) / 2 + 1}= 0, α_(N-1)= Α_L-Δα, α_N= Α_LAssume that Where -α_L And α_L Is a steering angle when the steering wheel is cut to the maximum in the left direction and the right direction, and is a unique and known value for the vehicle M. Δα is 2 × α_L/ N.
[0029]
The vehicle speed sensor 14 detects the current traveling speed (hereinafter simply referred to as speed) V of the vehicle M and transmits it to the processor 101. The yaw rate sensor 15 is connected to the first yaw rate ω₁Is transmitted to the processor 101. Here, FIG. 4 shows the first yaw rate ω.₁It is a schematic diagram for demonstrating. In FIG. 4, the vehicle M (only the outline is shown)₀And arrow A₀Retreats in the direction indicated by. Also, time t₀From time to time T, the vehicle M moves backward diagonally to the right as indicated by two dotted arrows. During this time T, the traveling direction of the vehicle M is the arrow A₀To arrow A₁It has changed in the direction indicated by. Now arrow A₀And A₁If the angle formed by the directions of β is β, the first yaw rate ω₁Is represented by the following equation (1).
ω₁= Β / T (1)
[0030]
Further, a vehicle coordinate system necessary for the following description will be described with reference to FIG. In FIG. 4, the vehicle coordinate system is X₁Axis, Y₁Axis and Z₁It is a three-dimensional orthogonal coordinate system composed of axes. First, Z₁The axis is the current center of gravity position P of the vehicle M_BYCThe vertical direction is shown with reference to. X₁The axis is the center of gravity P_BYCIndicates the traveling direction of the vehicle M. Y₁The axis is the center of gravity position P of the vehicle M_BYCWith reference to X above₁Axis and Z₁Indicates the direction perpendicular to the axis. The above-mentioned first yaw rate ω₁X above₁It is also the amount of rotation per time T of the shaft.
[0031]
Further, the display device 16 of FIG. 1 has a display image I described later._DPY(See FIG. 5) is displayed. The processor 101 performs the above-described captured image I._CPTTo display image I_DPYCreate Here, FIG. 5 shows the display image I._DPYIt is a schematic diagram which shows an example. In FIG. 5, the display image I_DPYIs the captured image I_CPTAnd the optimum trajectory LT and the predicted travel trajectory ET superimposed on the trajectory. The optimal trajectory LT is preferably the current position P of the vehicle M._CPTo its stop position P_SPIt is a figure showing the optimal locus until. In addition, the predicted travel locus ET is the current steering angle α_iWhen the vehicle M keeps the current position P_CPThis is a figure representing a trajectory assumed to be traced from now on. Stop position P_SP, Current position P_CPWill be described in detail in the description of the operation of the driving support device 1, so that the description thereof is omitted here.
[0032]
1 is mainly used as a working area for the processor 101. In particular, in the main memory 102, the display image I_DPYThe storage area in which it is created is called a frame memory. The program memory 103 is typically composed of a ROM (Read Only Memory), and software S necessary for the operation of the driving support device 1 is provided.₁Is stored. Software S₁As shown in FIG. 6, a computer program (hereinafter simply referred to as a program) C₁And a predetermined number of objects B. Program C₁Defines the operation of the driving support device 1. Each object B is the basis of the above-mentioned optimum locus LT or predicted traveling locus ET. That is, the processor 101 creates an optimal trajectory LT and an expected travel trajectory ET from the object B. Here, since the steering angle that can be detected by the steering angle sensor 13 is N as described above, N objects B are used as the predetermined number of objects B.₁~ B_NIs prepared. Object B₁~ B_NIs the steering angle α₁~ Α_NMore specifically, the steering angle α₁~ Α_NThe figure data specifies the shape of the trajectory that the vehicle M is supposed to follow while maintaining Object B_{(N-1) / 2 + 1}Object B except₁~ B_NSubstantially has a shape like a partial ring (that is, an arc shape and a belt shape). However, the steering angle α_{(N-1) / 2 + 1}Is 0, so object B_{(N-1) / 2 + 1}Only becomes a rectangular figure.
[0033]
Next, referring to FIGS. 7A and 7B, the object B_NAn exemplary data structure will be described. In FIG. 7A, object B_NIs r coordinate values P (r is a predetermined natural number)._v1~ P_vrConsists of. Where the coordinate value P_v1~ P_vrIs a coordinate value of the above-described vehicle coordinate system (see FIG. 4). The above coordinate value P_v1~ P_vrBy connecting the steering angle α as shown in FIG._NThe trajectory of the vehicle M at the time is expressed. In FIGS. 7A and 7B, four coordinate values P are shown for convenience._v1, P_vj, P_vkAnd P_vrOnly shown. Where the coordinate value P_v1And P_vrAre the coordinate values of the right rear wheel and the left rear wheel of the vehicle M, and the start line L of the trajectory of the vehicle M_STIdentify both ends of. Also, the coordinate value P_vjAnd P_vkIs the end line L of the trajectory of the vehicle M_TMIdentify both ends of.
[0034]
Other object B₁~ B_(N-1)The steering angle α₁~ Α_(N-1)Since the shape of the trajectory of the vehicle M according to the above is expressed by the same data structure as described above, detailed description thereof will be omitted.
[0035]
Next, operation | movement of the driving assistance apparatus 1 which has the above structure is demonstrated. First, when the driving support device 1 is turned on, the processor 101 reads the software S from the program memory 103.₁Are read into the main memory 102. Further, it is assumed that the vehicle M is currently located diagonally to the right of the parking space and that the driver is about to put the vehicle M into the parking space. At this time, the operation button 111 is operated by the driver, and as a result, the above-described start instruction D is sent to the processor 101._SDIs sent. Processor 101 receives reception start instruction D_SDIn response to the program C on the main memory 102₁Execution, that is, image display processing is started.
[0036]
Here, FIG. 8 and FIG.₁It is a flowchart which shows the operation | movement procedure of the driving assistance apparatus 1 described in (2). In FIG. 8, the processor 101 first starts the object B on the main memory 102.₁~ B_NA predetermined object B_jIs selected (step S1). Currently, the vehicle M is located diagonally right forward of the parking space. In such a situation, the driver turns the steering wheel in the right direction in order to put the vehicle M into the parking space. From the above, in step S1, the steering angle α having a positive value._{(N-1) / 2 + 2}~ Α_NObject B assigned to one of_jIs selected. That is, j is any natural number from (N−1) / 2 + 2 to N. In the following embodiments, for convenience, it is assumed that j is N, and the object B selected in step S1._jThe selected object B_NCalled.
[0037]
Next, the processor 101 generates an imaging instruction and transmits it to the imaging device 12. In response to the received imaging instruction, the imaging device 12 captures an image I representing a scene currently included in its field of view._CPT(See FIG. 3) is generated and stored in the frame memory in the main memory 102 (step S2). That is, in step S <b> 2, the image creation device 10 receives the captured image I from the imaging device 12._CPTReceive
[0038]
Next, the initial display image I shown in FIG._D0Is created and displayed (step S3). More specifically, in step S3, first, the selected object B_NCoordinate value P constituting_v1~ P_vrIs converted into a coordinate sequence of the image coordinate system by the processor 101. Here, the image coordinate system is a captured image I as shown in FIG._CPTX indicating the horizontal direction of₂Y indicating the axis and its vertical direction₂It consists of an axis. Such coordinate transformation is disclosed in, for example, International Publication No. WO 00-07373, and detailed description thereof is omitted here. The above-selected coordinate-selected object B_N(See the shaded area) is the captured image I on the frame memory._CPTThus, the initial display image I as shown in FIG._D0Is completed. Here, FIG. 10 further shows a stop position P where the driver wants to stop the vehicle M in the parking space._SPIt is shown. However, this stop position P_SPIs only shown because it is necessary for the following explanation, and the actual captured image I_CPTNote that it is not superimposed on. Initial display image I completed as described above_D0Is transferred to the display device 16 under the control of the processor 101, and the display device 16 receives the received initial display image I._D0Is displayed.
[0039]
Next, the processor 101 receives the confirmation notification D from the input device 11._NTIt is determined whether or not has arrived (step S4). Confirmation notification D_NTHas arrived, the processor 101 proceeds to step S5, otherwise returns to step S2. Here, in step S3 executed for the first time, the selected object B is simply used._NIs simply superimposed. Therefore, as shown in FIG._D0The selected object B_NTermination line L_TMIs the stop position P where the driver wants to stop the vehicle M._SPIs often not shown accurately. In this case, selected object B_NIs not yet the optimal path LT. Therefore, the driver is responsible for the initial display image I_D0While looking at this termination line L_TMIs the stop position P_SPThe vehicle M is moved so that If the two do not match, the driver does not operate the operation button 112, so “No” is determined in step S 4, and the driving support device 1 repeats a series of operations from step S 1 to S 4. During this time, each time step S3 is executed, a new initial display image I_D0Is created and displayed. From the above, with the passage of time, the termination line L_TMIs the stop position P_SPGet closer and closer.
[0040]
And the termination line L_TMIs the stop position P_SP, The initial display image I as shown in FIG._D0The selected object B_NIs the current position P of the vehicle M_CPTo stop position P_SPRepresents the optimum route LT up to. Here, in the following description, the termination line L_TMIs the stop position P_SPCurrent position P of vehicle M when_CPParking start position P_stCalled. At this time, the driver operates the operation button 112 for the first time, whereby the input device 11 receives the confirmation notification D described above._NTIs transmitted to the processor 101. Confirmation notification D when executing step S4 described above_NTIs already arrived, the processor 101 determines that the selected object B_NIs determined as the optimum trajectory LT and held in the main memory 102 (step S5). Further, after the operation button 112 is operated, the driver places the vehicle M in the parking start position P._stTo stop position P_SPStart moving towards.
[0041]
Next, the processor 101 performs initial setting (step S6). More specifically, first, the processor 101 sets the execution time of step S6 to the reference time t._REFSet as. Further, the processor 101 determines the second yaw rate ω of the vehicle M.₂Is the initial value ω₂₀And the current position P of the vehicle M_CPTo the initial position P₀Set to.
[0042]
Reference time t above_REFThe world coordinate system is defined by setting. Next, the world coordinate system will be described with reference to FIG. In FIG. 12, the world coordinate system indicates the reference time t._REF Center of gravity P of vehicle M at_BYCAs the origin and X_ThreeAxis, Y_ThreeAxis and Z_ThreeIt is a three-dimensional orthogonal coordinate system composed of axes. X_ThreeThe axis indicates the traveling direction of the vehicle M with respect to the origin. Z_ThreeThe axis indicates the vertical direction with respect to the origin. Y_ThreeThe axis is X_ThreeAxis and Z_ThreeOrthogonal to the axis. The above world coordinate system differs from the vehicle coordinate system described above in the following points. That is, the vehicle coordinate system moves with the vehicle M as shown in FIG._REF Center of gravity P of vehicle M at_BYCIt is fixed with. That is, the world coordinate system does not move even when the vehicle M moves.
[0043]
Next, referring to FIG. 12, the second yaw rate ω₂Will be explained. In FIG. 12, the vehicle M has a reference time t_REFAnd the above X_ThreeIt is retracting in the axial direction. Also, the reference time t_REFTo current time t_CPIn the meantime, the vehicle M moves backward diagonally to the right as indicated by two dotted arrows. During this time, the traveling direction of the vehicle M is X_ThreeArrow A from the axial direction₂The direction is changing. The current time t_CPCenter of gravity P of vehicle M at_BYCTo X_ThreeAuxiliary line L parallel to the axis_a2pull. In addition, auxiliary line L_a2And arrow A₂If the angle formed by the direction of γ is γ, the second yaw rate ω₂Is represented by the following equation (2).
ω₂= Γ / (t_CP-T_REF) ... (2)
The first yaw rate ω₁Is the yaw rate of the vehicle M on the vehicle coordinate system, whereas the above-mentioned second yaw rate ω₂Is different on the world coordinate system. In addition, the above initial value ω₂₀Is the reference time t_REFSecond yaw rate at₂And 0.
[0044]
In addition, the current position P_CPIs the current time t_CPCenter of gravity P of vehicle M at_BYCAnd the coordinate value of the world coordinate system (x_CP, Y_CP, Z_CP). In addition, the initial position P₀Is the reference time t_REFCenter of gravity P of vehicle M at_BYCAnd the coordinate value of the world coordinate system (x_CP0, Y_CP0, Z_CP0). That is, the initial position P₀Is (0, 0, 0) since it is the origin of the world coordinate system.
[0045]
Next, the processor 101 performs the captured image I from the imaging device 12 in the same manner as in step S1._CPT(FIG. 8; step S7). Next, the processor 101 determines the steering angle α of the vehicle M from the steering angle sensor 13, the vehicle speed sensor 14, and the yaw rate sensor 15._i, Velocity V and first yaw rate ω₁Is received (steps S8 to 10).
[0046]
Next, the processor 101 receives the received velocity V and the first yaw rate ω.₁Is used to determine the movement amount TA of the vehicle M (step S11). More specifically, the processor 101 first receives the received first yaw rate ω.₁Is substituted into the following equation (3) to obtain the second yaw rate ω₂Is calculated. The processor 101 cannot use the above equation (2) because the angle γ cannot be detected in this embodiment.
[Expression 1]

Next, the processor 101 calculates the calculated second yaw rate ω₂And the received velocity V is substituted into the following equations (4) and (5), and the coordinate value x_CPAnd y_CPIs calculated. In this embodiment, the coordinate value z_CPIs a constant value over time (ie z_CP0) Is not calculated.
[Expression 2]

In the above equations (4) and (5), δ is the skid angle of the center of gravity of the vehicle M, and can be regarded as 0 when the vehicle M is traveling at a low speed as in parking. Coordinate value x_CPAnd y_CPAfter the calculation, the processor 101 determines that the initial position P₀Travel distance TA (x_CP-X_CP0, Y_CP-Y_CP0) Is calculated.
[0047]
After step S11, the processor 101 uses the above movement amount TA to deform the currently held optimum locus LT, and creates and holds the current optimum locus LT (step S12). More specifically, the vehicle M has a reference time t_REFTo current time t_CPIn the meantime, it has moved by the above-mentioned movement amount TA. As described above, the optimal trajectory LT is the current position P._CPTherefore, the amount corresponding to the amount of movement TA is unnecessary in the optimum trajectory LT that is being held.
[0048]
For example, as shown in FIG._REFAt the time of the optimal trajectory LT (selected object B_N) Starting line L_STCoordinate value P_v1And P_vrIs necessary. However, with time, the vehicle M_REFSince it feels like moving on the optimal locus LT at the time of, the reference time t_REFIf the time passes, the coordinate value P_v1And P_vrIs no longer needed. Therefore, in step S12 that is executed for the first time, the processor 101 determines that the coordinate sequence P that constitutes the held optimum route LT._v1~ P_vrFrom the vehicle M, the reference time t_REFTo current time t_CPRegion R moved up to_M1Is deleted, and the current optimum locus LT is created. Here, moving region R_M1Is x_v1X_v1+ (X_CP-X_CP0) The following range.
[0049]
In step S12 executed after the second time as well, as in the first time, the processor 101 determines that the vehicle M is the reference time t from the coordinate sequence constituting the optimum route LT being held._REFTo current time t_CPRegion R moved up to_M1Is deleted, and the current optimum locus LT is created.
[0050]
Next, the processor 101 creates an expected traveling locus ET (step S13). More specifically, the processor 101 first sets the object B on the main memory 102.₁~ B_NFrom the current steering angle α obtained in step S8._iObject B assigned to_qSelect. Here, q is any natural number from 1 to N. Next, the processor 101 determines that the object B_qAt least four coordinate values are selected from the coordinate sequence that constitutes. At this time, object B_qStarting line L_STAlways include two coordinate values indicating (see FIG. 7).
[0051]
Following step S13, the display image I shown in FIG._DPYIs created and displayed (step S14). Step S14 will be described more specifically. First, the coordinate sequence of the vehicle coordinate system that forms the optimum route LT created in step S12 is converted into the coordinate sequence of the image coordinate system. Furthermore, the coordinate sequence of the vehicle coordinate system that constitutes the predicted travel locus ET created in step S13 is converted into the coordinate sequence of the image coordinate system. Such coordinate transformation is disclosed in, for example, International Publication No. WO 00-07373, and detailed description thereof is omitted here. The coordinate-converted optimum route LT and the predicted traveling locus ET are captured image I stored in the frame memory in step S7._CPTIs superimposed on the current time t_CPDisplay image I_DPYIs completed. Next, the completed display image I is controlled under the control of the processor 101._DPYIs transferred to the display device 16, and the display device 16 receives the received display image I._DPYIs displayed.
[0052]
Next, the processor 101 receives the above-described end instruction D from the input device 11._TDIt is determined whether or not has arrived (step S15). End instruction D_TDHas arrived, the processor 101 determines that the vehicle M is at the stop position P_SPThe image display process is terminated, otherwise the next display image I_DPYIn order to create the process, the process returns to step S7.
[0053]
Here, FIG. 14 shows the reference time t._REFTo end instruction D_TDDisplay image I displayed on the display device 16 before the arrival of_d It is a schematic diagram which shows how is changed. FIG. 14 shows a display image I for four frames._DPYIt is shown. Uppermost display image I_d Is the reference time t_REFIs displayed by executing the above-described processing. The lower display image I_DPY Is the time (t_REF+ Δt). Furthermore, the time (t_REF+ Δt) and (t_REFDisplay image I displayed at (+ 2 × Δt)_DPY It is shown. In addition, at the bottom of FIG._REF+ 3 × Δt) and the end instruction D_TDImage I just before arrival_DPY It is shown. Display image I_DPY As you can see from the change over time, the end instruction D_TDAs the vehicle approaches, the shape of the optimum trajectory LT changes according to the movement of the vehicle M on the screen of the display device 16, and more specifically, the stop position P of the vehicle M._SPAn optimal locus LT that shrinks toward is displayed. Further, the vehicle M is displayed so as to follow the shrinking optimum trajectory LT. As a result, the driver can stop the parking position P in the parking space._SPIt becomes easy to confirm whether the vehicle M is heading correctly.
[0054]
Furthermore, the display image I_d In addition to the optimal trajectory LT, the predicted travel trajectory ET is also synthesized. If the driver performs an appropriate steering wheel operation, the vehicle M is correctly stopped._SP14, the predicted traveling locus ET is displayed on the screen of the display device 16 so as to move on the optimum locus LT as shown in FIG. However, if the driver performs an inappropriate handle operation, the display image I shown in FIG._DPYAs described above, the predicted traveling locus ET deviates from the optimum locus LT. As a result, the driver can instantly notice an error in the steering wheel operation, and can provide a more convenient driving support device 1.
[0055]
Further, in the above embodiment, both the optimal trajectory LT and the predicted travel trajectory ET are taken as the captured image I._CPTIt was described as being superimposed on. However, in order to solve the problem set in the present application, at least the optimum trajectory LT may be superimposed. In addition, the captured image I in which distortion generated in the lens of the imaging device 12 is corrected is corrected._CPTBoth the optimal trajectory LT and the predicted travel trajectory ET may be superimposed on each other.
[0056]
In the above embodiment, the driver performs the initial display image I._D0While looking at this termination line L_TMIs the stop position P_SPAs described above, the vehicle M has been described as being moved. As a result, the optimum trajectory LT is the current position P of the vehicle M._CPTo its stop position P_SPIt was supposed to represent up to. However, the present invention is not limited to this, and the driving support device 1 is not limited to₁Immediately after starting execution of the object B, a predetermined object B_jMay be selected as the optimum route LT. In this case, the initial display image I_D0In object B_j(That is, the termination line L of the optimum route LT)_TMIs usually the stop position P_SPDo not instruct. Even in such an optimum route LT, the driver can stop at the stop position P._SPThere is a technical effect that the optimum route to the middle of the route can be understood. That is, the optimum route LT is at least the current position P of the vehicle M._CPThe optimal route from
[0057]
In the above embodiment, the captured image I_CPTIs an image of the rear of the vehicle M viewed from the position of the imaging device 12 as a viewpoint. However, the present invention is not limited to this._CPTIs subjected to viewpoint conversion processing to create an image (hereinafter referred to as a viewpoint conversion image) in which the rear of the vehicle M is viewed from a viewpoint other than the position of the imaging device 12 (for example, above the vehicle M). May superimpose the optimal trajectory LT and / or the predicted travel trajectory ET on the generated viewpoint conversion image to generate a display image (hereinafter referred to as a viewpoint conversion display image). Further, the processor 101 performs the display image I described above._DPYAlternatively, the above-described viewpoint conversion display images may be combined and displayed on the display device 16 at the same time.
[0058]
Moreover, although the imaging device 12 was demonstrated as 1 unit | set in the above embodiment, multiple units | sets may be sufficient. In this case, the processor 101 uses the captured images I from a plurality of units._CPTAre connected to one image, and then the optimum trajectory LT and / or the predicted travel trajectory ET are superimposed to create a display image. Further, the imaging device 12 does not necessarily have to be fixed at an equal distance from both side surfaces of the vehicle M, and the longitudinal center plane S_CThe vehicle M may be fixed at a position shifted in the left-right direction. Even if the imaging device 12 is installed in this way, the driving support device 1 displays the display image I when viewed from the center of the vehicle M by the viewpoint conversion process described above._DPYCan be created.
[0059]
In the above embodiment, the captured image I_CPTAs will be apparent from the above description, the situation in which the vehicle M is parked from the diagonally right front of the parking space between the two vehicles arranged in the left-right direction has been described as an example. However, the present image creation apparatus 10 can be easily applied not only to such an example but also to a situation where parking is performed from the diagonally left front of the parking space. Furthermore, the present invention can also be applied when parking between two vehicles arranged in the front-rear direction. However, in this case, as shown in FIG. 16, the vehicle M moves toward the parking space so as to draw an S shape, and therefore the object B representing such a shape._SMust be prepared in advance.
[0060]
In the above embodiment, the optimal trajectory LT and the predicted travel trajectory ET are expressed by planar figures. However, the present invention is not limited to this and may be expressed by simple lines.
[0061]
“Second Embodiment”
By the way, in 1st Embodiment, in step S10 of FIG. 9, the processor 101 is 1st yaw rate (omega) from the yaw rate sensor 15.₁Was receiving. However, in the second embodiment, the first yaw rate ω₁An object of the present invention is to provide a driving support device 2 that can calculate the above.
[0062]
FIG. 17 is a block diagram illustrating a hardware configuration of the driving support apparatus 2 in which the image creation apparatus 20 according to the second embodiment is incorporated. In FIG. 17, the driving support device 2 does not require the yaw rate sensor 15 as compared with the driving support device 1 shown in FIG.₁Instead of software S as shown in FIG.₂Is different in that is stored. Since there is no difference other than that, in FIG. 17, the thing equivalent to the structure of FIG. 1 is attached with the same referential mark, and the description is abbreviate | omitted. Software S₂As shown in FIG.₁Compared to (see FIG. 6), program C₁A computer program (hereinafter simply referred to as a program) C₂It differs in that it includes. Since the object B is the same as that of the first embodiment, the description thereof is omitted in this embodiment. Program C₂Defines the operation of the driving support device 2.
[0063]
Next, operation | movement of the driving assistance apparatus 2 which has the above structure is demonstrated. After the driving support device 2 is turned on, the processor 101 first starts the software S from the program memory 103.₂Are read into the main memory 102. The processor 101 sends a start instruction D from the input device 11_SDIn response to the reception of the program C on the main memory 102₂Execution, that is, image display processing is started.
[0064]
Here, FIG. 19 and FIG.₂It is a flowchart which shows the operation | movement procedure of the driving assistance apparatus 2 described in (2). The flowcharts of FIGS. 19 and 20 differ from the flowcharts of FIGS. 8 and 9 in that step S10 is replaced with step S21. Other than that, there is no difference between the two flowcharts. Therefore, in FIG. 19 and FIG. 20, the steps corresponding to the steps of FIG. 8 and FIG.
[0065]
Hereinafter, before the specific description of step S10, parameters and theories required there will be described with reference to the drawings. First, FIG. 21 shows a vehicle M whose mass is m. Further, the center of gravity position P of the vehicle M_BYCTo the line connecting the rotation centers of both front wheels_fIn addition, the distance to the line segment connecting the rotation centers of both rear wheels is D_rfar. If the wheel base of the vehicle M is L, L = (D_f+ D_r). Further, although not shown in FIG. 21, the yawing moment of inertia of the vehicle M is expressed as I_mThe front wheel cornering power of vehicle M_f, Rear wheel cornering power K_rAnd Mass m above, yawing moment of inertia I_m, Wheelbase L, distance D_f, Distance D_rFront wheel cornering power K_f, And rear wheel cornering power K_rIs a known value that is unique to the vehicle M.
[0066]
In FIG. 21, the actual steering angle of the front wheels of the vehicle M is set to ε. Here, the actual steering angle ε is the steering angle α of the steering wheel α of the vehicle M._iIt can be calculated by the following equation (6).
ε = B × α_i... (6)
Here, B is a known constant specific to the vehicle M.
Further, FIG. 21 shows the traveling direction of the vehicle M (vector of the speed V) and the first yaw rate ω.₁And the side slip angle δ are shown. However, since these are described in the first embodiment, the description thereof is omitted here.
[0067]
The equation of motion of the vehicle M having the above parameters is expressed by the following equation (7).
[Equation 3]

Further, the center of gravity position P of the vehicle M_BYCThe yaw motion equation around the vertical axis is expressed by the following equation (8).
[Expression 4]

By arranging the above equations (7) and (8), the following equations (9) and (10) are obtained.
[Equation 5]

[0068]
Furthermore, when the above equations (9) and (10) are Laplace transformed, the equation of motion and the yawing equation of motion of the vehicle M are expressed as the following equation (11).
[Formula 6]

Here, s is a Laplace operator.
[0069]
In step S21 in FIG. 20, the processor 101 determines that the steering angle α received in steps S8 and S9._iAnd the moving amount TA of the vehicle M is obtained using the speed V. More specifically, the processor 101 determines that the received steering angle α_iIs substituted into the previous equation (6) to calculate the actual steering angle ε. Therefore, in the above equation (11), the unknown is the first yaw rate ω₁It becomes only. Note that δ is a side slip angle, but is a known value because it can be regarded as 0 when the vehicle M is traveling at a low speed as in parking. After calculating the actual rudder angle ε, the processor 101 solves the above equation (11) using the received speed V and the calculated actual rudder angle ε to obtain the first yaw rate ω.₁Is calculated (step S21).
[0070]
In the next step S11, the processor 101 starts with the first yaw rate ω calculated in step S21.₁Is substituted into the previous equation (3) and the second yaw rate ω₂Is calculated. Thereafter, the processor 101, as described in the first embodiment, moves the movement amount TA (x_CP-X_CP0, Y_CP-Y_CP0) Is calculated.
As described above, according to the present embodiment, since the yaw rate sensor 15 is not required as in the driving support device 1, the technical effect that the configuration of the driving support device 2 can be simplified can be obtained.
[0071]
“Third Embodiment”
In the first embodiment, the processor 101 receives the speed V from the vehicle speed sensor 14 in step S9 of FIG. However, an object of the third embodiment is to provide a driving support device 3 that can calculate the speed V.
[0072]
FIG. 22 is a block diagram illustrating a hardware configuration of the driving support device 3 in which the image creation device 30 according to the second embodiment is incorporated. In FIG. 22, the driving support device 3 does not require the vehicle speed sensor 14 as compared with the driving support device 1 shown in FIG.₁Instead of software S as shown in FIG._ThreeIs the point where is stored. Since there is no difference other than that, in FIG. 22, the thing equivalent to the structure of FIG. 1 is attached with the same referential mark, and the description is abbreviate | omitted. In FIG. 23, software S_ThreeIs software S₁Compared to (see FIG. 6), program C₁A computer program (hereinafter simply referred to as a program) C_ThreeIt differs in that it includes. Since the object B is the same as that of the first embodiment, the description thereof is omitted in this embodiment. Program C_ThreeDefines the operation of the driving support device 3.
[0073]
Next, operation | movement of the driving assistance apparatus 3 which has the above structure is demonstrated. After the driving support device 3 is turned on, the processor 101 first starts the software S from the program memory 103._ThreeAre read into the main memory 102. The processor 101 sends a start instruction D from the input device 11_SDIn response to the reception of the program C on the main memory 102_ThreeExecution, that is, image display processing is started.
[0074]
Here, FIG. 24 and FIG._ThreeIt is a flowchart which shows the operation | movement procedure of the driving assistance apparatus 3 described in (2). The flowcharts of FIGS. 24 and 25 are different from the flowcharts of FIGS. 8 and 9 in that step S9 is replaced with step S31. Other than that, there is no difference between the flowcharts, and therefore, in FIG. 24 and FIG. 25, the steps corresponding to the steps in FIG. 8 and FIG.
[0075]
Hereinafter, measurement of the vehicle speed by the spatial filtering necessary therefor will be described before specific description of step S31. The spatial filtering is described in detail in, for example, the spatial filter and its application [I] (Journal of the Society of Instrument and Control Engineers “Measurement and Control” Vol. 19, No. 4). FIG. 26 is a schematic diagram showing the basic principle of spatial filtering. In FIG. 26, a slit row 41, a point light source 42, and an optical system 43 are shown. The slit row 41 has the same plane S_SLTA plurality of slits arranged in the same direction at a constant pitch p. The point light source 42 emits light toward the slit row 41 while moving on the slit row 41 in the arrangement direction at a relative speed V ′ with respect to the slit row 41. The optical system 43 is placed between the slit row 41 and the point light source 42 and allows the light from the point light source 42 to pass therethrough. The light passing through the optical system 43 is focused on the slit row 41. Thus, on the slit row 41, the spot light L_SPTIs projected.
[0076]
Further, as shown in FIG. 26, the above-described spot light L is located at a position where the point light source 42 is viewed with the slit row 41 interposed therebetween._SPT, The spot light L passing through the slit row 41_SPTIs a signal in which one pulse appears for each displacement p in the arrangement direction of the slits. The period T of such a signal (pulse)_CYLBecomes p / V '. Also, the frequency f of the signal_SPTV ′ / p, which is proportional to the relative speed V ′. That is, the spot light L_SPTWhen the relative speed V ′ of the motor fluctuates with time, the frequency f ′_SPTAlso changes. However, spot light L_SPTIs plane S_SLTThe property that one pulse appears in the optical signal each time it moves by the displacement p is unchanged.
[0077]
In addition, the above-described captured image I_CPTIt can be considered that a large number of point light sources having many light intensities are randomly arranged in the general optical pattern as described above. In addition, it can be considered that a large number of point light sources included in the optical pattern are simultaneously moved in a certain direction without changing the positional relationship with each other. When such an optical pattern is replaced with the point light source 42 in FIG. 26 and moved in the same manner as the point light source, at the position where the point light source 42 is viewed between the slit rows 41, the same frequency f is obtained._SPTHowever, a signal obtained by adding (synthesizing) a large number of signals having different phases and amplitudes is observed. Hereinafter, the observed signal is referred to as a narrowband random signal. Average frequency f of this narrowband random signal_AVEIs V '/ p as described above, and its phase and amplitude vary irregularly and slowly over time.
[0078]
Next, from the narrowband random signal having the waveform as described above, the relative velocity V ′ of the optical pattern itself._PTNThe calculation method of will be described. FIG. 27 shows the relative speed V ′._PTNIt is a schematic diagram of the model used for calculation. In FIG. 27, an optical pattern 51, a spatial filter 52, an optical system 53, and a photodetector 54 are shown. The optical pattern 51 has a random light intensity distribution f (x, y). The spatial filter 52 is disposed in close contact with the optical pattern 51. The spatial filter 52 is a point P in the two-dimensional orthogonal coordinate system._FLTThe length in the x-axis direction is X_FLTAnd the length in the y-axis direction is Y_FLTAnd a spatial load function having a predetermined transmittance distribution h (x, y). The spatial filter 52 described above passes light emitted from the optical pattern 51. The optical system 53 focuses the light that has passed through the spatial filter 52. The photodetector 54 converts the light collected by the optical system 53 into electricity, and outputs an instantaneous output g (x₀, Y₀) Is generated. Here, instantaneous output g (x₀, Y₀) Is expressed by the following equation (12) when the proportionality constant is ignored.
[0079]
[Expression 7]

Where x₀And y₀Is the origin P of the spatial filter 52_FLTIt is the x coordinate value and the y coordinate value of the optical pattern 51 located above.
[0080]
In the above model, the optical pattern 51 has a constant velocity V ′ in the x-axis direction._PTN X when moving in parallel₀And y₀Is represented by the following equations (13) and (14).
x₀= V ’_PTN ・ T + c₁... (13)
y₀= C₂... (14)
Where t is time and c₁And c₂Is a constant.
[0081]
Now y₀And g (x₀, Y₀) For displacement x₀When the power spectral density function Ψ (μ) in the spatial region in the x-axis direction is expressed as the following expression (15):
[Equation 8]

Here, μ and ν are spatial frequencies in the x-axis direction and the y-axis direction. H (μ, ν) is expressed by the following equation (16). Φ (μ, ν) is a two-dimensional power spectral density function in the spatial domain with respect to f (x, y).
[Equation 9]

[0082]
Further, the above equation (15) is approximately expressed as the following equation (17) assuming that the transmittance distribution h (x, y) is constant in the y-axis direction.
[Expression 10]

Here, H (μ) is expressed by the following equation (18).
## EQU11 ##

[0083]
Here, the speed V ′ of the optical pattern 51._PTN In order to consider the influence of the instantaneous output g (x₀, Y₀) To a function g (x of time t₀, Y₀, T), the power spectral density function Ω (f) in the time domain is expressed by the following equation (19).
[Expression 12]

Here, f is a temporal frequency.
[0084]
In the above formulas (15) to (19), | H (μ) |²Is μ = μ₀Φ (μ₀, 0) = 0, unless Ψ (μ) is μ = μ₀And has a steep spectrum. Therefore, for Ω (f), f = Vμ₀A prominent spectrum appears at. Therefore, the speed V ′_PTN A sine wave signal with a frequency proportional to the instantaneous output g (x₀, Y₀, T), and by performing frequency measurement represented by Fourier transform or wavelet transform on the sine wave signal, the velocity V ′_PTN Can be detected.
[0085]
In order to apply the above spatial filtering to the driving support device 3, as shown in FIG._CPTIn the storage area, a virtual slit row 61 is set in advance. The slit row 61 is a plurality of slits arranged in the same direction at a constant pitch p in the memory space of the main memory 102, and the captured image I_CPTRoad surface S_RIt is placed where it is assumed that is reflected. The position and shape of each slit are specified by the coordinate values of the image coordinate system described in the first embodiment. In step S31, the processor 101 determines the captured image I in the main memory 102._CPTThe plurality of pixels included in the slit row 61 are regarded as the optical pattern 51 described above, and spatial filtering is performed on the optical pattern 51.
[0086]
More specifically, generally, the captured image I_CPTIn the case of black and white, it includes data indicating the luminance value of each pixel constituting the black and white. In the case of color, the captured image I_CPTIncludes data indicating the luminance values of the three primary colors of light for each pixel, but can be converted into monochrome luminance values by a well-known method. First, the processor 101 stores the captured image I stored this time._CPTAre used to add the black and white luminance values of all the pixels included in the slit row 61. As a result, the processor 101 obtains the total luminance value and stores it on the main memory 102. Here, the main memory 102 stores the captured images I for the past several frames including the current total value._CPTA recording area for storing the total value obtained from the above is reserved. Accordingly, the main memory 102 stores data indicating changes in the total value on the time axis as shown in FIG. Next, the processor 101 converts the change of the total value represented on the time axis into that on the frequency axis as shown in FIG. 29B, and then, from the obtained total value on the frequency axis, Detect peak value. Further, the processor 101 detects a frequency component f corresponding to the detected peak value. Thereafter, the processor 101 determines the optical pattern 51, that is, the road surface S, from the detected frequency component f and the pitch p described above._RRelative speed V 'to vehicle M_PTN(= P / f) is calculated. The processor 101 uses the relative velocity V ′ thus obtained._PTNIs reversed to derive the speed V of the vehicle M (step S31).
[0087]
As described above, according to the present embodiment, the vehicle speed sensor 14 is not required as in the driving support device 1, so that the technical effect that the configuration of the driving support device 3 can be simplified can be obtained.
[0088]
In the above first to third embodiments, the program C₁~ C_ThreeIs stored in the program memory 103. However, the program C is not limited to this.₁~ C_ThreeMay be distributed in a state of being recorded on a recording medium typified by a CD-ROM, or may be distributed through a communication network typified by the Internet.
[0089]
In addition to the method described in the above embodiment, there is a method using a well-known Ackermann model as a method for deriving the current optimum route LT. In the Ackermann model, the optimum path LT is the steering angle α._iAnd the speed V.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a hardware configuration of a driving support apparatus 1 according to a first embodiment of the present invention.
FIG. 2 is a schematic diagram showing a fixed position of the image pickup apparatus 12 of FIG.
3 is a captured image I generated by the imaging device 12 of FIG._CPTIt is a schematic diagram which shows an example.
4 is a first yaw rate ω detected by the yaw rate sensor 15 of FIG.₁It is a schematic diagram for demonstrating.
5 is a display image I created by the processor 101 of FIG._DPYIt is a schematic diagram which shows an example.
6 is software S stored in the program memory 103 of FIG.₁It is a schematic diagram which shows the detailed structure of these.
7 is an object B shown in FIG._NIt is a schematic diagram for demonstrating.
8 is a first half of a flowchart showing an operation procedure of the driving support device 1 of FIG. 1;
9 is the latter half of the flowchart showing the operation procedure of the driving support device 1 of FIG. 1;
10 is a notification of confirmation I in step S3 of FIG._NTInitial display image I created before arrival_D0It is a schematic diagram which shows.
11 is an initial display image I displayed at the time of step S5 in FIG._D0It is a schematic diagram which shows.
12 is a second yaw rate ω calculated in step S11 of FIG. 9;₂It is a schematic diagram for demonstrating.
FIG. 13 is a schematic diagram for explaining the processing content of the processor 101 in step S12 of FIG. 9;
14 is a schematic diagram showing a change of the display screen of the display device 16 of FIG. 1 with respect to time. FIG.
15 is a display image I displayed on the display device 16 of FIG. 1 when the driver makes a handle operation mistake._DPYIt is a schematic diagram which shows.
FIG. 16 is an object B shown in FIG._NObject B, an alternative to_SIt is a schematic diagram for demonstrating.
FIG. 17 is a block diagram showing a hardware configuration of a driving support apparatus 2 according to a second embodiment of the present invention.
18 shows software S stored in the program memory 103 of FIG.₂It is a schematic diagram which shows the detailed structure of these.
FIG. 19 is a first half of a flowchart showing an operation procedure of the driving support apparatus 2 of FIG. 17;
20 is the latter half of the flowchart showing the operation procedure of the driving support apparatus 2 of FIG.
FIG. 21 is a schematic diagram showing parameters of the vehicle M required in step S21 of FIG.
FIG. 22 is a block diagram showing a hardware configuration of a driving support apparatus 3 according to a third embodiment of the present invention.
23 shows software S stored in the program memory 103 of FIG._ThreeIt is a schematic diagram which shows the detailed structure of these.
24 is a first half portion of a flowchart showing an operation procedure of the driving support device 3 of FIG. 22;
25 is the latter half of the flowchart showing the operation procedure of the driving support device 3 of FIG.
26 is a schematic diagram showing a basic concept of spatial filtering applied to the driving support device 3 of FIG.
FIG. 27 shows the relative velocity V ′ of the spatial pattern 51 using the spatial filtering of FIG._PTNIt is a schematic diagram of the model used for calculation.
FIG. 28 is a schematic diagram showing slit rows 61 set in advance in the driving support device 3 of FIG. 22;
FIG. 29 shows the relative speed V ′ in step S31 of FIG._PTNIt is a schematic diagram for demonstrating the detection method.
FIG. 30 is a display image I for four frames displayed on a conventional monitor device._d1~ I_d4It is a schematic diagram which shows.
[Explanation of symbols]
1, 2, 3 ... Driving support device
10, 20, 30 ... Image creation device
101. Processor
102 ... Main memory
103 ... Program memory
S₁, S₂, S_Three…software
C₁, C₂, C_Three... Computer program
11 ... Input device
111, 112, 113 ... operation buttons
12 ... Imaging device
13. Steering angle sensor
14 ... Vehicle speed sensor
15 ... Yaw rate sensor
16 ... Display device

Claims (6)

An image creation device for driving support of a vehicle,
An imaging device installed in the vehicle;
A steering angle sensor for detecting a steering angle of the vehicle;
A processor that creates a display image based on an image captured by the imaging device and a steering angle detected by the steering angle sensor;
A main memory assigned to a plurality of steering angles and storing a plurality of objects which are graphic data for specifying the shape of a trajectory that the vehicle is supposed to follow while maintaining the steering angles;
A display device for displaying the display image created by the processor;
An input device for receiving an operation input of a driver of the vehicle ,
The processor is
The object assigned to a predetermined steering angle is selected from the main memory, and an initial display image is created by superimposing on the scene represented by the image captured by the imaging device ,
The display device displays the initial display image;
Wherein the input device, the input of the information indicating that the object displayed on the initial display image by the movement of the vehicle is optimal locus representing the optimal trajectory to the stop position from the current position of the vehicle, from the driver If accepted Ru,
The processor is
Based on the information received by the input device, the object displayed in the initial display image is determined as the optimal locus,
Based on the steering angle detected by the steering angle sensor, using the object stored in the main memory, create an expected traveling locus that the vehicle is expected to follow from now on,
An image creation device that creates a display image in which the optimum trajectory and the predicted travel trajectory are superimposed on the scene in the main memory. The processor transfers the display image created by being superimposed on the main memory to a display device connected to be communicable with the processor,
The image creation device according to claim 1, wherein the display device displays a received display image from the main memory. An image creation method for driving support of a vehicle, wherein a plurality of graphic data is assigned to a plurality of steering angles and specifies a shape of a trajectory that the vehicle is supposed to follow while maintaining the steering angles. The object is stored in the main memory,
A steering angle detecting step for detecting a steering angle of the vehicle;
A display image creation step of creating a display image based on the image captured by the imaging device and the steering angle detected in the steering angle detection step;
A display step for displaying the display image created in the display image creation step;
An initial display image creation step of creating an initial display image by selecting the object assigned to a predetermined steering angle from the main memory and superimposing the object on a scene represented by the image captured by the imaging device ; ,
An initial display image display step for displaying the initial display image;
Optimal trajectory input of information indicating that the object displayed on the initial display image by the movement of the vehicle is optimal trajectory representing the optimal trajectory to the stop position from the current position of the vehicle receives from the vehicle driver An input step;
An optimal trajectory determining step for determining an object displayed in the initial display image as the optimal trajectory based on the information received in the optimal trajectory input step;
The steering angle detected based on the steering angle detected in step, with the objects stored in said main memory, a predicted travel locus generating step of generating a predicted traveling locus in which the vehicle is expected to follow from this,
And a creation step of creating, in the main memory, a display image in which the optimal trajectory and the predicted travel trajectory are superimposed on the scene. A transfer step of transferring a display image created by being superimposed on the main memory to a display device connected to be communicable with itself;
The image creation method according to claim 3, further comprising: a received display image display step for displaying a received display image from the main memory. An image creation program executed by a computer of an image creation device for driving support of a vehicle, which is assigned to a plurality of steering angles, and a shape of a trajectory assumed to be followed by the vehicle while maintaining the steering angles Multiple objects that are graphic data that identify
In the computer,
A steering angle detecting step for detecting a steering angle of the vehicle;
A display image creation step of creating a display image based on the image captured by the imaging device and the steering angle detected in the steering angle detection step;
A display step for displaying the display image created in the display image creation step ;
An initial display image creation step of creating an initial display image by selecting the object assigned to a predetermined steering angle from the main memory and superimposing the object on a scene represented by the image captured by the imaging device ; ,
An initial display image display step for displaying the initial display image;
Optimal trajectory input of information indicating that the object displayed on the initial display image by the movement of the vehicle is optimal trajectory representing the optimal trajectory to the stop position from the current position of the vehicle receives from the vehicle driver An input step;
An optimal trajectory determining step for determining an object displayed in the initial display image as the optimal trajectory based on the information received in the optimal trajectory input step;
The steering angle detected based on the steering angle detected in step, with the objects stored in said main memory, a predicted travel locus generating step of generating a predicted traveling locus in which the vehicle is expected to follow from this,
An image creation program for executing a creation step of creating a display image in which the optimum trajectory and the predicted travel trajectory are superimposed on the scene in the main memory. A transfer step of transferring a display image created by being superimposed on the main memory to a display device connected to be communicable with itself;
The image creation program according to claim 5, wherein a reception display image display step of displaying a reception display image from the main memory is executed.

Images