JP3596174B2 - Image data generation method - Google Patents

Description

【００８５】
ただし、上記式（２）において、αは、図１０に示すように、被写体５０又は撮影装置５２の回転中心５０ａと、撮影装置５２の視点位置５２ａとを結ぶ仮想線をＬａとし、拡大又は縮小処理の対象となる画像位置Ｐａと、撮影装置５２の視点位置５２ａとを結ぶ仮想線をＬｂとしたとき、仮想線Ｌａと仮想線Ｌｂとの間の角度を示している。
【００８６】
このように各画像の画像データについてキーストン歪みの補正処理を施すことにより、視差画像列の画像データは、撮影装置５２を平行に動かしたときに得られる画像データと同様なものとなる。したがって、このようにキーストン歪みを補正することにより、平面状のホログラフィックステレオグラムを作成したときに、キーストン歪みに起因する画像の乱れが生じるようなことがなくなる。
【００８７】
以上のようなキーストン歪みの補正処理の流れについて詳細に説明する。
【００８８】
ここで、視差画像列の各画像は、視差方向となる横方向と、非視差方向となる縦方向とに複数の画素を有している。具体的には、例えば、図１１に示すように、１画像毎に横方向に４８０［ｐｉｘｅｌ］の画素を有し、縦方向に６４０［ｐｉｘｅｌ］の画素を有するようにする。このとき、１画像は、縦方向に６４０［ｐｉｘｅｌ］の画素が並んだ画素列ｇが、横方向に４８０［ｐｉｘｅｌ］分だけ並んで構成されることとなる。
【００８９】
そして、キーストン歪みを補正する際は、図１２に示すように、先ず、ステップＳＴ２−１において、キーストン歪みの補正の対象となる画像を構成する各画素列ｇにそれぞれ対応する上記角度αを計算する。
【００９０】
次に、ステップＳＴ２−２において、上記式（２）に基づいて、１つの画素列ｇについて、当該画素列ｇに対応する上記比率ｒａｔｉｏを計算する。
【００９１】
次に、ステップＳＴ２−３において、ステップＳＴ２−２で算出された比率ｒａｔｉｏに基づいて、当該画素列ｇによる画像に対して拡大又は縮小処理を行い、当該画素列ｇによる画像のキーストン歪みを補正する。
【００９２】
また、このとき、元となる画像を撮影した撮影装置５２の受光面と、ホログラム用記録媒体３０の露光面とが互いに平行となるように、すなわち、撮影装置５２によって撮影された元画像と、ホログラム用記録媒体３０に記録される画像とが互いに平行となるように、画像データの座標変換を行う。
【００９３】
この座標変換では、図１０に示すように、撮影装置５２で撮影された元画像の座標位置ｘ’と、ホログラム用記録媒体３０に記録される画像の座標位置ｘとを設定し、ホログラム用記録媒体３０に記録される画像上において等間隔でサンプリングされた複数の点について、下記式（３）で表されるαを算出する。
【００９４】
【数２】

【００９５】
そして、上記式（３）で算出されたαから、ホログラム用記録媒体３０に記録される画像の座標位置ｘに対応した元画像の座標位置ｘ’を、下記式（４）より算出する。
【００９６】
ｘ’＝ｄ_ｖ ・ｔａｎα ・・・（４）
上記式（３）及び式（４）から、元画像の座標位置ｘ’と、ホログラム用記録媒体３０に記録される画像の座標位置ｘとの関係が明らかとなる。そこで、上記式（３）及び式（４）に基づいて座標変換を行い、ホログラム用記録媒体３０に記録される画像が、ホログラム用記録媒体３０に対して平行な画像となるように、画像データのマッピングを行う。なお、実際の計算では、ｄ_ｖ 、ｘ、ｘ’の単位系を、画像データを構成する各画素に対応させて行う。
【００９７】
次に、ステップＳＴ２−４において、全ての画素列ｇについてキーストン歪みの補正が完了したかを判別する。そして、キーストン歪みの補正が完了していない画素列ｇがあるときは、ステップＳＴ２−２に戻って、キーストン歪みの補正が完了していない画素列ｇに対してキーストン歪みの補正を施す。
【００９８】
一方、キーストン歪みの補正が完了していない画素列ｇが無く、全ての画素列ｇについてキーストン歪みの補正が完了しているときには、ステップＳＴ２−５に進む。
【００９９】
ステップＳＴ２−５において、キーストン歪みの補正が全ての画像について完了したかを判別する。そして、キーストン歪みの補正が完了していない画像があるときは、ステップＳＴ２−１に戻って、キーストン歪みの補正が完了していない画像に対してキーストン歪みの補正を施す。
【０１００】
以上の処理により、視差画像列を構成する全画像に対して、キーストン歪みの補正処理が完了する。
【０１０１】
なお、以上のようなキーストン歪みの補正処理を行うタイミングは、後述する視点変換処理の前であれば、いつ行ってもよい。すなわち、キーストン歪みの補正は、例えば、視差画像列撮影システムから画像データ処理部６０に１画像分の画像データが入力される毎に行うようにしてもよいし、また、視差画像列撮影システムから画像データ処理部６０に視差画像列を構成する全画像の画像データが入力された後に行うようにしてもよい。
【０１０２】
つぎに、以上にようにキーストン歪みの補正処理が施された画像データに対して施される視点変換処理について説明する。
【０１０３】
ホログラフィックステレオグラムにおいて、撮影時における撮影装置５２の視点と被写体５０との位置関係は、作成されたホログラフィックステレオグラムの再生像に対しても保持されるため、撮影された視差画像列の画像データをそのまま用いてホログラフィックステレオグラムを作成すると、図１３に示すように、再生像６０はホログラフィックステレオグラムＨのホログラム面Ｈａよりも奥に結像してしまう。このため、このようなホログラフィックステレオグラムＨでは、再生像６０と視点６１の距離ｄ_ｖ０が撮影時における被写体５０の中心から撮影装置５２の視点までの距離ｄ_ｖ に一致するように、観察時に視点６１をホログラム面Ｈａにおいて再生像６０を見ない限り、再生像６０に歪みが生じてしまう。
【０１０４】
また、特に白色光によって再生される白色再生ホログラフィックステレオグラムでは、再生像６０の結像位置がホログラム面Ｈａから遠ざかるほど、再生像６０がぼける性質があるため、上述のように再生像６０がホログラム面Ｈａよりも奥に結像してしまうと、再生像６０がぼけてしまう。
【０１０５】
そこで、これらの問題を解決するために、元の画像データに対して視点変換処理を施し、図１４に示すように、再生像６２がホログラフィックステレオグラムＨのホログラム面Ｈａ近傍に結像するようにする。これにより、ホログラム面Ｈａから離れた位置に視点６３をおいても、歪みやぼけのない再生像６２が得られることとなる。
【０１０６】
この視点変換処理では、視差画像列生成時の画像の視点位置と、ホログラム露光時の画像の視点位置との関係に基づいて、横視差方向の画像のマッピングを行い、ホログラム面Ｈａから離れた視点６３に対応した画像の画像データを生成する。すなわち、視点変換処理では、視差画像列の複数の画像の画像データに対して、縦方向のスリット状の画像のデータである画素列ｇの順序を入れ替え、これにより、視点位置を変換した新たな画像データを再構築する。
【０１０７】
視点変換処理の詳細な説明の前に、視点変換処理の元となる視差画像列について、図１５を参照して説明する。
【０１０８】
この図１５において、Ｈは、ホログラフィックステレオグラムを示し、ｅ_１ ，ｅ_２ ，・・・，ｅ_ｎ−１ ，ｅ_ｎ は、要素ホログラムの露光位置を示しており、Ｗは、ホログラフィックステレオグラムＨの横方向の長さを示し、ｄ_ｖ は、被写体５０の中心から撮影装置５２の視点までの距離を示している。また、ｖ_１ ，ｖ_２ ，・・・，ｖ_ｎ−１ ，ｖ_ｎ は、視差画像列を撮影する際の撮影装置５２の視点位置を示し、θ_ｖ は、撮影時の画角を示しており、Ｐ_１ ，Ｐ_２ ，・・・，Ｐ_ｎ−１ ，Ｐ_ｎ は、撮影された視差画像列の各画像を示し、Ｑ_１ ，Ｑ_２ ，・・・，Ｑ_ｎ−１ ，Ｑ_ｎ は、キーストン歪みの補正が施された画像を示している。
【０１０９】
この図１５に示すように、複数の画像Ｐ_１ ，Ｐ_２ ，・・・，Ｐ_ｎ−１ ，Ｐ_ｎ からなる視差画像列は、視点Ｖ_１ からＶ_ｎ までの間を、撮影装置５２を同一の曲率で回動させて順次撮影することにより得られる。そして、これらの画像Ｐ_１ ，Ｐ_２ ，・・・，Ｐ_ｎ−１ ，Ｐ_ｎ に対して、上述のようにキーストン歪みを補正することにより、キーストン歪みが補正された画像Ｑ_１ ，Ｑ_２ ，・・・，Ｑ_ｎ−１ ，Ｑ_ｎ が得られる。そして、視点変換処理では、キーストン歪みが補正された画像Ｑ_１ ，Ｑ_２ ，・・・，Ｑ_ｎ−１ ，Ｑ_ｎ から視点変換が施された新たな画像データを生成する。
【０１１０】
ここで、ホログラフィックステレオグラムＨの中心を原点とし、ホログラフィックステレオグラムＨに平行な横方向をＸ軸、ホログラフィックステレオグラムＨに垂直でＸ軸に直交する方向をＺ軸としたとき、視点ｖ_１ の座標（ｘ_１ ，ｚ_１ ）は、下記式（５）で示すように設定し、視点ｖ_ｎ の座標（ｘ_ｎ ，ｚ_ｎ ）は、下記式（６）で示すように設定する。これにより、後述する視点変換処理に必要な視差画像列が得られることとなる。
【０１１１】
【数３】

【０１１２】
ところで、図１５に示すように、撮影装置５２によって撮影された画像Ｐ_１ ，Ｐ_２ ，・・・，Ｐ_ｎ−１ ，Ｐ_ｎ の視点位置ｖ_１ ，ｖ_２ ，・・・，ｖ_ｎ−１ ，ｖ_ｎ は、円弧状に移動している。これは、キーストン歪みが補正された画像Ｑ_１ ，Ｑ_２ ，・・・，Ｑ_ｎ−１ ，Ｑ_ｎ においても同様であり、これらの画像Ｑ_１ ，Ｑ_２ ，・・・，Ｑ_ｎ−１ ，Ｑ_ｎ の視点位置も、円弧状に移動している。このように、円弧状に視点位置が移動している視差画像列を、このまま平面状のホログラム記録媒体に記録すると再生像が歪んでしまう。そこで、再生像がホログラム面上に結像するように視点位置を変換する際に、同時に、視点位置がホログラム面に対して平行に移動するように変換する。
【０１１３】
以下、視点変換処理について、視点変換処理の様子を示す図１６と、視点変換の流れを示す図１７のフローチャートとを参照して説明する。
【０１１４】
なお、図１６では、元の視差画像列から、要素ホログラムの露光位置ｅ_ｍ に対応した１枚の露光用画像Ｒ_ｍ の画像データを再構成する様子を示しており、実際は、要素ホログラムの露光位置ｅ_１ ，ｅ_２ ，・・・，ｅ_ｎ−１ ，ｅ_ｎ に対応した露光用画像Ｒ_１ ，Ｒ_２ ，・・・，Ｒ_ｎ−１ ，Ｒ_ｎ の画像データをそれぞれ再構成する。具体的には、要素ホログラムの数は、５００程度であり、露光用画像の画像データも、これらの数だけ再構成する。ただし、要素ホログラムの数は、作成するホログラフィックステレオグラムの大きさと要素ホログラムの露光ピッチによって決まるものであり、当然の事ながら、要素ホログラムの数は５００に限定されるものではない。
【０１１５】
また、以下の説明において、各画像は、横方向に４８０［ｐｉｘｅｌ］の画素を有し、縦方向に６４０［ｐｉｘｅｌ］の画素を有するものとする。すなわち、この視点変換処理では、キーストン歪みが補正された画像Ｑ_１ ，Ｑ_２ ，・・・，Ｑ_ｎ−１ ，Ｑ_ｎ から、横方向に４８０［ｐｉｘｅｌ］の画素を有し、縦方向に６４０［ｐｉｘｅｌ］の画素を有する画像の画像データを、要素ホログラムの分だけ生成する。
【０１１６】
視点変換処理を行う際は、図１７に示すように、先ず、ステップＳＴ３−１において、露光用画像Ｒを横方向の解像度に対応させて画素列毎に分割し、各画素列に対応した分割点ｒｍを設定する。なお、ここでの露光用画像Ｒ_ｍ は、横方向に４８０［ｐｉｘｅｌ］の画素を有しているので、露光用画像をスリット状の４８０本の画素列に分割し、各画素列に対応した４８０の分割点ｒを設定する。このとき、各画素列は、横方向に１［ｐｉｘｅｌ］の画素を有し、縦方向に６４０［ｐｉｘｅｌ］の画素を有するものとなる。
【０１１７】
次に、ＳＴ３−２において、ステップＳＴ３−１で設定された分割点ｒのうちの１つを選択し、当該分割点ｒと、要素ホログラムの露光位置ｅ_ｍ とを結ぶ仮想線ｋ_１ を定義する。このとき、露光用画像Ｒ_ｍ と、ホログラフィックステレオグラムＨとの間の距離ｄ_ｖ１は、元の視差画像列の視点が通る円弧Ｖ_ｐａｔｈの半径に一致させ、露光用画像の画角θ_ｅｖは、図２に示したホログラム用記録媒体３０上に物体光を集束させるためのシリンドリカルレンズ４２の画角θ_ｓ と一致させる。
【０１１８】
次に、ＳＴ３−３において、ステップＳＴ３−２で定義された仮想線ｋ_１ と、元の視差画像列の視点が通る円弧Ｖ_ｐａｔｈとの交点を算出する。
【０１１９】
次に、ＳＴ３−４において、キーストン歪みが補正された画像の視点位置の中から、ステップＳＴ３−３で算出された交点に最も近い視点位置ｖ_ｍ を探索する。
【０１２０】
次に、ＳＴ３−５において、キーストン歪みが補正された画像の中から、ステップＳＴ３−４で探索された視点位置Ｖ_ｍ を視点とする画像Ｑ_ｍ を選択する。
【０１２１】
次に、ＳＴ３−６において、ステップＳＴ３−４で探索された視点位置ｖ_ｍ と、要素ホログラムの露光位置ｅ_ｍ とを結ぶ仮想線ｋ_２ を定義する。
【０１２２】
次に、ＳＴ３−７において、ステップＳＴ３−６で定義された仮想線ｋ_２ と、ステップＳＴ３−５で選択された画像Ｑ_ｍ との交点ｊ_ｍ を算出する。
【０１２３】
次に、ＳＴ３−８において、ステップＳＴ３−５で選択された画像Ｑ_ｍ を構成する画素列の中から、ステップＳＴ３−７で算出された交点ｊ_ｍ に位置する画素列を選択し、選択された画素列を、露光用画像Ｒ_ｍ の分割点ｒに対応する画素列にマッピングする。
【０１２４】
すなわち、キーストン歪みが補正された画像の画素列のうち、図１６において■で示される交点ｊ_ｍ に位置する画素列が、露光用画像Ｒ_ｍ の●で示される位置にマッピングされる。
【０１２５】
次に、ＳＴ３−９において、全ての分割点ｒについて、画素列のマッピングが完了したかを判別する。そして、全ての分割点ｒについてマッピングが完了していないときは、ステップＳＴ３−２に戻って、マッピングが完了していない分割点ｒについて、画素列のマッピングを行う。
【０１２６】
以上の処理により、１枚の露光用画像Ｒ_ｍ について視点変換処理が完了し、１枚の露光用画像Ｒ_ｍ の画像データが再構成され生成される。
【０１２７】
そして、この視点変換処理を各要素ホログラムの露光位置ｅ_１ ，ｅ_２ ，・・・，ｅ_ｎ−１ ，ｅ_ｎ に対応させて繰り返し行い、要素ホログラムの数だけ露光用画像Ｒ_１ ，Ｒ_２ ，・・・，Ｒ_ｎ−１ ，Ｒ_ｎ の画像データを再構成する。これにより、再生像がホログラム面上に結像するように視点位置が変換されるとともに、視点位置がホログラム面に対して平行に移動するようになされた視差画像列の画像データが生成される。
【０１２８】
ところで、視点変換処理は、画素列を入れ替えて新たな画像データを生成することにより実現される。そして、この入れ替えの順序は、視点変換処理のパラメータが同じであるならば、視差画像列が異なっていても同じである。したがって、視点変換処理において、元となる視差画像列の視点等が同じであるならば、上述のような計算を繰り返し行う必要はなく、画素列の入れ替えの順序を記録したデータを用意しておき、当該データを参照して、画素列の入れ替えを行うようにしてもよい。
【０１２９】
すなわち、初回だけ、図１７に示したフローに従って視点変換処理を行い、このときに、元の画像の画素列と、露光用画像の画素列との対応関係を求め、当該対応関係をハードディスクドライブ装置等の外部記憶装置に保存しておき、次回以降の視点変換処理では、この対応関係に基づいて、視点変換処理を行うようにしてもよい。これにより、計算処理の繰り返しが無くなり、処理速度を大幅に向上することができる。
【０１３０】
以上のように、キーストン歪みの補正処理と、視点変換処理とを行い、視差画像列の画像データを再構成し、再構成された画像データを用いてホログラフィックステレオグラムを作成することにより、再生像がホログラム面上に歪むことなく結像する平面状のホログラフィックステレオグラムを作成することが可能となる。
【０１３１】
すなわち、このような画像データに基づいて作成されたホログラフィックステレオグラムでは、横方向の視差に関してはキーストン歪みの補正処理及び視点変換処理により、視点位置情報が補正されている。また、縦方向については、視差画像撮影時の情報がそのまま保存されている。したがって、このような画像データに基づいて作成されたホログラフィックステレオグラムでは、撮影時の撮影装置の視点の移動と同様に、視点を円弧状に移動させることにより、ホログラム面近傍に歪むことなく再生される再生像を観察することができる。
【０１３２】
【発明の効果】
以上の説明から明らかなように、本発明によれば、被写体が大きくても、視差画像列を得るための視差画像列撮影システムを小型化することができる。しかも、撮影装置の画角を大きく取る必要がないので、広角レンズのような特別なレンズを用いる必要がなく、撮影装置の低コスト化を図ることもできる。
【０１３３】
また、本発明では、無駄な画像データが少なくて済むので、データを有効に利用することができる。したがって、例えば、同じ量の画像データを扱った場合、従来に比べて、ホログラフィックステレオグラムの画質を向上することができる。
【０１３４】
しかも、本発明では、撮影された複数の画像の画像データに対してキーストン歪みの補正処理を施しているので、本発明に係る画像データ生成方法によって生成された画像データでは、平面状のホログラフィックステレオグラムを作成することができる。
【図面の簡単な説明】
【図１】ホログラフィックステレオグラム作成システムの一構成例を示すブロック図である。
【図２】ホログラフィックステレオグラムプリンタ装置の光学系の一構成例を示す図である。
【図３】視差画像列撮影システムの一例を示す模式図である。
【図４】視差画像列撮影システムの他の例を示す模式図である。
【図５】ホログラフィックステレオグラムと撮影装置の画角との関係を示す図である。
【図６】画像データ処理部の一構成例を示すブロック図である。
【図７】画像データ処理のフローチャートである。
【図８】被写体の正面に撮影装置が位置しているときの撮影の様子と、撮影された画像とを示す図である。
【図９】被写体の正面に撮影装置が位置していないときの撮影の様子と、撮影された画像とを示す図である。
【図１０】キーストン歪みの補正処理に用いるパラメータを示す図である。
【図１１】視差画像列を構成する画像の一例を示す図である。
【図１２】キーストン歪み補正処理のフローチャートである。
【図１３】視点変換処理を行わずに作成したホログラフィックステレオグラムからの再生像を観察する様子を示す模式図である。
【図１４】視点変換処理を行った上で作成したホログラフィックステレオグラムからの再生像を観察する様子を示す模式図である。
【図１５】視点変換処理の元となる視差画像列と、ホログラフィックステレオグラムとの位置関係を示す図である。
【図１６】視点変換処理を説明するための図である。
【図１７】視点変換処理のフローチャートである。
【図１８】ホログラフィックステレオグラムの作成方法を示す模式図である。
【図１９】従来の視差画像列撮影方法の一例を示す図である。
【図２０】従来の視差画像列撮影方法の他の例を示す図である。
【符号の説明】
１ 画像データ生成部、 ２ 制御用コンピュータ、 ３ ホログラフィックステレオグラムプリンタ装置、 ５０ 被写体、 ５１ 回転台、 ５２ 撮影装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image data generating method for generating image data of an image recorded on a holographic stereogram.
[0002]
[Prior art]
A holographic stereogram is a method in which a large number of images obtained by sequentially photographing an object from different observation points are used as original images, and these are sequentially recorded as strip-shaped or dot-shaped element holograms on a single hologram recording medium. It is produced by
[0003]
For example, when creating a holographic stereogram having parallax information only in the horizontal direction, as shown in FIG. 18, first, the subject 100 is sequentially photographed from different observation points in the horizontal direction, so that the parallax information in the horizontal direction is obtained. Is obtained from a plurality of images having a parallax image sequence 101. Then, each image 102 of the parallax image sequence is sequentially recorded as a strip-shaped element hologram on the hologram recording medium 103 so as to be continuous in the lateral direction. Thereby, a holographic stereogram having parallax information in the horizontal direction is obtained.
[0004]
In the holographic stereogram, information of a plurality of images obtained by sequentially photographing from different observation points in the horizontal direction is sequentially recorded so as to be continuous in the horizontal direction as a strip-shaped element hologram. When the observer views the holographic stereogram with both eyes, the two-dimensional images appearing in the left and right eyes are slightly different. As a result, the observer feels parallax, and a three-dimensional image is reproduced.
[0005]
[Problems to be solved by the invention]
By the way, as shown in FIG. 19, for example, as shown in FIG. 19, the parallax image sequence which is an image serving as a source of the holographic stereogram is obtained by moving the photographing device 111 toward the subject 110 while keeping its direction constant, as indicated by an arrow B1 Are obtained by photographing a large number of subjects 110 from different positions by moving them in parallel as shown in FIG. That is, the photographing device 111 facing the subject 110 is moved in parallel from the position where the subject 110 enters the photographing range of the photographing device 111 to the position where the subject 110 is out of the photographing range of the photographing device 111, and during this time, a large number of Take an image.
[0006]
However, in such a photographing method, when the subject 110 is large, the moving distance of the photographing device 111 needs to be large in order to photograph the entire image, and the entire parallax image sequence photographing system for obtaining a parallax image sequence is required. There is a problem that the size of the image becomes large.
[0007]
Also, when taking a picture as described above, the angle of view θ _v Is reflected in the horizontal viewing angle of the holographic stereogram, so it is desirable to keep it sufficiently large. However, the angle of view θ of the photographing device 111 _v It is necessary to use a wide-angle lens in order to obtain a large value, which causes an increase in the cost of the imaging device 111. Further, the angle of view θ of the photographing device 111 using a wide-angle lens _v If the image is taken with a large value, the image is likely to be distorted, which causes deterioration of the image quality of the holographic stereogram.
[0008]
Further, when the parallax image sequence is photographed as described above, the image of the parallax image sequence includes many unnecessary portions where the subject 110 is not shown. In particular, in the first image and the last image in the parallax image sequence, the subject 110 is captured only at the edge of the image, and most of the portion is an unnecessary portion unrelated to the subject 110. Therefore, when image data is generated from the parallax image sequence, a large amount of useless image data is included, which is extremely disadvantageous in terms of effective use of the data.
[0009]
Alternatively, a parallax image sequence, which is an image that is a source of a holographic stereogram, is obtained by, for example, placing the subject 110 on a turntable 112, fixing the photographing device 111, and photographing the subject 110, as shown in FIG. In addition, as shown by an arrow B2 in the figure, by rotating the turntable 112 by a predetermined angle, a plurality of images having different viewpoints can be obtained.
[0010]
Such a photographing method, compared with a method of moving the photographing device 111 in parallel as shown in FIG. 19, reduces the size of the entire parallax image sequence photographing system for obtaining a parallax image sequence even if the subject 110 is large. There is an advantage that the size can be reduced. Also, the angle of view θ of the photographing device 111 _v Is small, a sufficient horizontal viewing angle can be obtained by rotating the subject 110. Furthermore, since the subject 110 is always located in front of the photographing device 111 even when the turntable 112 is rotated, an unnecessary portion where the subject 110 is not shown in the image of the parallax image sequence is hardly included. Therefore, when image data is generated from the parallax image sequence, useless image data is hardly included, which is very advantageous in terms of effective use of data.
[0011]
However, since the conventional holographic stereogram is created corresponding to the viewpoint at the time of shooting, the holographic stereogram created based on the parallax image sequence obtained by rotating the subject 110 as described above. Becomes an arc-shaped object corresponding to the viewpoint of the photographing device 111. However, considering that the holographic stereogram creating system is put into practical use as a printer device that outputs a hard copy capable of obtaining a three-dimensional image, it is naturally preferable that the holographic stereogram is planar.
[0012]
The present invention has been proposed in view of such a conventional situation, and is an image data generation method for generating image data corresponding to a planar holographic stereogram. Image data generation that can reduce the size of the parallax image sequence photographing system, does not require a large angle of view of the photographing device, and uses less data with less wasteful image data. It is intended to provide a way.
[0013]
[Means for Solving the Problems]
The image data generation method according to the present invention, which has been completed to achieve the above-described object, includes a method of rotating a subject or a photographing device while maintaining a distance between the subject and the photographing device substantially constant, to obtain a plurality of images having different viewpoints. A keystone distortion correction process is performed on image data of a plurality of captured images, and a viewpoint position is converted for the keystone distortion correction image data. Perform the conversion process, Flat Generate image data of an image to be recorded on the holographic stereogram.
Further, in the image data generating method according to the present invention, the subject or the photographing device is rotated, a plurality of images having different viewpoints are photographed by the photographing device, and the image data of the photographed images are arranged in the vertical direction. Correction of keystone distortion by obtaining a ratio based on when the imaging device is located in front of the subject corresponding to the pixel row, and performing enlargement or reduction processing for each vertical line of the image based on the ratio. The image data that has been subjected to the keystone distortion correction processing is subjected to viewpoint conversion processing for converting the position of the viewpoint to generate image data of an image to be recorded on a planar holographic stereogram.
Further, in the image data generation method according to the present invention, the subject or the photographing device is rotated in the horizontal direction with respect to the screen, and a plurality of images having different viewpoints are photographed by the photographing device. For each vertical line according to the rotation angle due to the rotation of the imaging device with respect to the time when the camera is moving, the coordinate position of the image where the holographic stereogram is recorded, and the distance between the imaging device and the viewpoint position. Determine the ratio, perform an enlargement or reduction process on each vertical line of the image according to the ratio, perform a viewpoint conversion process for converting the position of the viewpoint on the image data subjected to the enlargement or reduction process, Generate image data of an image to be recorded on a planar holographic stereogram.
The image data generating apparatus according to the present invention, which has been completed to achieve the above-described object, includes a plurality of different viewpoints captured by rotating the subject or the photographing device while keeping the distance between the subject and the photographing device substantially constant. Keystone distortion correction means for performing keystone distortion correction processing on image data of a plurality of input images, and image data on which keystone distortion correction processing has been performed. Viewpoint conversion means for performing a viewpoint conversion process for converting the position of the viewpoint and generating image data of an image to be recorded on a planar holographic stereogram.
Further, the image data generating device according to the present invention is configured such that image data of a plurality of images having different viewpoints taken by rotating a subject or a photographing device is input, and the image data of the input plurality of images is vertically aligned. A keystone distortion is obtained by obtaining a ratio based on when the imaging device is located in front of the subject corresponding to the aligned pixel row, and performing enlargement or reduction processing for each vertical line of the image based on the ratio. Image processing means for performing the correction processing of the image, and performing the viewpoint conversion processing for converting the position of the viewpoint on the image data on which the correction processing of the keystone distortion has been performed, and the image of the image to be recorded in the planar holographic stereogram. Viewpoint conversion means for generating data.
Further, the image data generating device according to the present invention is configured such that image data of a plurality of images of different viewpoints taken by rotating a subject or a photographing device in a lateral direction with respect to a screen is input, and an image pickup device is provided in front of the subject. Depending on the angle of rotation of the imaging device with respect to the position of the holographic stereogram, and the coordinate position of the image where the holographic stereogram is recorded, and the distance between the imaging device and the viewpoint position. An image processing unit that obtains a ratio for each line and performs an enlargement or reduction process on each vertical line of the image according to the ratio, and converts a viewpoint position with respect to the image data that has been subjected to the enlargement or reduction process. Viewpoint conversion means for performing a viewpoint conversion process and generating image data of an image to be recorded in a planar holographic stereogram.
[0014]
Here, when photographing a plurality of images having different viewpoints, for example, placing the subject on a turntable and rotating the turntable by a predetermined angle each time the subject is photographed, the plurality of images having different viewpoints can be captured. Shoot. Alternatively, for example, every time a subject is photographed, a plurality of images having different viewpoints are photographed by rotating the photographing device by a predetermined angle about the subject.
[0015]
When performing the viewpoint conversion process, for example, for pixels constituting an image subjected to the keystone distortion correction process, data is exchanged for each pixel column, and a reproduced image is formed near the hologram surface of the holographic stereogram. Generates image data of an image to be recorded on the holographic stereogram such that an image is formed.
[0016]
In the image data generation method according to the present invention as described above, since the subject or the imaging device is rotated to capture a plurality of images having different viewpoints, compared to a method in which the imaging device is moved in parallel, even if the subject is large, In addition, the size of the entire parallax image sequence photographing system for obtaining the parallax image sequence can be reduced. Further, even if the angle of view of the imaging device is small, a sufficient horizontal viewing angle can be obtained by rotating the subject or the imaging device. Further, even if the photographing position is moved, the subject is always located in front of the photographing device, and therefore, unnecessary portions where the subject is not shown in the image of the parallax image sequence are hardly included. Therefore, when image data is generated from the parallax image sequence, useless image data is hardly included, which is very advantageous in terms of effective use of data.
[0017]
Furthermore, in the image data generating method according to the present invention, the keystone distortion correction processing is performed on the image data of a plurality of captured images, so that the image data is obtained when the imaging device is moved in parallel. The image data is the same as the image data of the image. Therefore, the holographic stereogram created based on the image data obtained by the image data generating method according to the present invention is a planar holographic stereogram.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.
[0019]
First, a configuration example of a holographic stereogram creating system to which the present invention is applied will be described.
[0020]
This holographic stereogram creation system is a system for creating a so-called one-step holographic stereogram, in which a film-shaped holographic recording medium on which interference fringes between object light and reference light are recorded is used as a holographic stereogram. is there.
[0021]
As shown in FIG. 1, the holographic stereogram creating system includes an image data generating unit 1 for generating image data of an image to be recorded on the holographic stereogram, and a control computer 2 for controlling the entire system. And a holographic stereogram printer device 3 having an optical system for creating a holographic stereogram.
[0022]
The image data generation unit 1 applies the present invention to generate image data of a plurality of images corresponding to a plurality of element holograms recorded in a holographic stereogram. The generation of the image data by the image data generation unit 1 will be described later in detail.
[0023]
When recording an image on the hologram recording medium, the image data generation unit 1 sends the generated image data D1 to the holographic stereogram printer device 3 for each image in the order of recording on the hologram recording medium. At the same time, every time the image data D1 is sent to the holographic stereogram printer 3, a timing signal S1 indicating that the image data D1 has been sent is sent to the control computer 2.
[0024]
The control computer 2 drives the holographic stereogram printer device 3 based on the timing signal S1 from the image data generation unit 1 and converts the image based on the image data D1 generated by the image data generation unit 1 into a holographic stereogram. The holograms are sequentially recorded as strip-shaped element holograms on a hologram recording medium set in the gram printer device 3.
[0025]
At this time, the control computer 2 controls a shutter, a recording medium feed mechanism, and the like provided in the holographic stereogram printer device 3 as described later. That is, the control computer 2 sends a control signal S2 to the holographic stereogram printer device 3 to control opening and closing of the shutter, feeding operation of the hologram recording medium by the recording medium feeding mechanism, and the like.
[0026]
The holographic stereogram printer device 3 will be described in detail with reference to FIG. FIG. 2A is a view of the entire optical system of the holographic stereogram printer 3 as viewed from above, and FIG. 2B is a view of the optical system of the holographic stereogram printer 3 for the object light. 3 is a view of a portion viewed from a lateral direction.
[0027]
As shown in FIG. 2A, the holographic stereogram printer device 3 includes a laser light source 31 for emitting laser light of a predetermined wavelength, and a shutter disposed on the optical axis of the laser light L1 from the laser light source 31. 32 and a half mirror 33. The shutter 32 is controlled by the control computer 2 and is closed when the hologram recording medium 30 is not exposed, and is opened when the hologram recording medium 30 is exposed. The half mirror 33 is for separating the laser light L2 passing through the shutter 32 into reference light and object light, and the light L3 reflected by the half mirror 33 is used as reference light. The light L4 transmitted through becomes the object light.
[0028]
On the optical axis of the light L3 reflected by the half mirror 33, as a reference light optical system, a cylindrical lens 34, a collimator lens 35 for converting the reference light into parallel light, and a parallel light from the collimator lens 35 Are arranged in this order.
[0029]
The light reflected by the half mirror 33 is first diverged by the cylindrical lens 34. Next, the light is collimated by the collimator lens 35. Thereafter, the light is reflected by the total reflection mirror 36 and enters the hologram recording medium 30.
[0030]
On the other hand, as shown in FIGS. 2A and 2B, the transmitted light from the half mirror 33 is reflected on the optical axis of the light L4 transmitted through the half mirror 33 as an optical system for object light. Total reflection mirror 38, a spatial filter 39 combining a convex lens and a pinhole, a collimator lens 40 for converting object light into parallel light, a display device 41 for displaying an image to be recorded, and a hologram for converting the object light to a hologram. And a cylindrical lens 42 for condensing light on the recording medium 30 for printing.
[0031]
Then, the light L <b> 4 transmitted through the half mirror 33 is reflected by the total reflection mirror 38, and is then converted into diffused light from a point light source by the spatial filter 39. Next, the light is collimated by the collimator lens 40 and then enters the display device 41. Here, the display device 41 is a transmissive image display device including, for example, a liquid crystal panel, and displays an image based on the image data D1 sent from the image data generation unit 1. Then, the light transmitted through the display device 41 is modulated according to the image displayed on the display device 41, and then enters the cylindrical lens 42.
[0032]
The light transmitted through the display device 41 is converged in the lateral direction by the cylindrical lens 42, and the converged light is incident on the hologram recording medium 30 as object light. That is, in the holographic stereogram printer device 3, the projection light from the display device 41 is incident on the hologram recording medium 30 as strip-shaped object light.
[0033]
Here, the reference light and the object light are such that the reference light is incident on one main surface of the hologram recording medium 30 and the object light is incident on the other main surface of the hologram recording medium 30. That is, the reference light is made incident on one main surface of the hologram recording medium 30 at a predetermined incident angle, and the object light is incident on the other main surface of the hologram recording medium 30 with respect to the hologram recording medium 30. The light is incident so that the optical axis is almost perpendicular. As a result, the reference light and the object light interfere with each other on the hologram recording medium 30, and interference fringes caused by the interference are recorded on the hologram recording medium 30 as a change in the refractive index.
[0034]
Further, the holographic stereogram printer device 3 includes a recording medium feeding mechanism 43 that can intermittently feed the hologram recording medium 30 under the control of the control computer 2. The recording medium feeding mechanism 43 is configured to output one image based on the image data D1 generated by the image data generating unit 1 to the hologram recording medium 30 set in the recording medium feeding mechanism 43 in a predetermined state. Every time a hologram is recorded as an element hologram, the hologram recording medium is intermittently advanced by one element hologram based on a control signal S2 from the control computer 2. As a result, images based on the image data D1 generated by the image data generating unit 1 are sequentially recorded as element holograms on the hologram recording medium 30 so as to be continuous in the horizontal direction.
[0035]
In the holographic stereogram printer device 3, the optical path length of the reference light reflected by the half mirror 33 and entering the hologram recording medium 30 and the hologram recording medium 30 transmitted through the half mirror 33 and via the display device 41. It is preferable that the optical path length of the object light incident on the optical path be substantially the same. Thereby, the coherence between the reference light and the object light increases, and the image quality of the holographic stereogram improves.
[0036]
Further, in the holographic stereogram printer device 3, a diffusion plate may be provided on the optical path of the object light in order to improve the image quality of the holographic stereogram. By disposing the diffusion plate in this manner, noise included in the object light is dispersed, and the light intensity distribution of the object light incident on the hologram recording medium becomes more uniform, so that the holographic stereogram to be created is Image quality is improved.
[0037]
However, when disposing the diffusion plate in this manner, it is preferable to dispose a mask having a strip-shaped opening corresponding to the shape of the element hologram between the diffusion plate and the hologram recording medium 30. By arranging the mask in this manner, an extra portion of the object light diffused by the diffusion plate is blocked by the mask, and a higher-quality holographic stereogram can be created.
[0038]
Further, in the holographic stereogram printer device 3, a one-dimensional diffusing plate for vertically diffusing the object light is disposed on the optical path of the object light so that the holographic stereogram has a vertical viewing angle. You may. By arranging the one-dimensional diffuser in this way, the object light is diffused in the vertical direction, that is, in the long axis direction of the element hologram to be created, whereby the created holographic stereogram has a vertical viewing angle. Will have.
[0039]
However, when such a one-dimensional diffusion plate is provided, it is preferable to provide a louver film having a fine grid-like lattice between the hologram recording medium 30 and the one-dimensional diffusion plate. By disposing the louver film in this manner, it is possible to prevent the reference light transmitted through the hologram recording medium 30 from being reflected by the one-dimensional diffusion plate and entering the hologram recording medium 30 again.
[0040]
Next, the operation of the holographic stereogram creating system will be described.
[0041]
When creating a holographic stereogram, the image data generator 1 sends the image data D1 to the display device 41 of the holographic stereogram printer device 3 and displays an exposure image based on the image data D1 on the display device 41. Let it. At this time, the image data generator 1 sends a timing signal S1 to the control computer 2 indicating that the image data D1 has been sent to the display device 41 of the holographic stereogram printer device 3.
[0042]
Then, the control computer 2 having received the timing signal S1 sends the control signal S2 to the shutter 32, opens the shutter 32 for a predetermined time, and exposes the hologram recording medium 30. At this time, of the laser light L2 emitted from the laser light source 31 and transmitted through the shutter 32, the light L3 reflected by the half mirror 33 enters the hologram recording medium 30 as reference light. Further, the light L4 transmitted through the half mirror 33 becomes projection light on which the image displayed on the display device 41 is projected, and the projection light enters the hologram recording medium 30 as object light. As a result, the exposure image displayed on the display device 41 is recorded on the hologram recording medium 30 as a strip-shaped element hologram.
[0043]
When the recording of one image on the hologram recording medium 30 is completed, the control computer 2 sends a control signal S2 to the recording medium feeding mechanism 43 to send the hologram recording medium 30 by one element hologram. Let
[0044]
The above operation is repeated by sequentially changing the exposure images to be displayed on the display device 41 in the parallax image sequence. Thus, the exposure image based on the image data generated by the image data generation unit 1 is sequentially recorded on the hologram recording medium 30 as a strip-shaped element hologram.
[0045]
When the element holograms are sequentially recorded as described above, the hologram recording medium 30 slightly vibrates when the hologram recording medium is sent by the recording medium feeding mechanism 43. Therefore, each time the hologram recording medium 30 is fed, the vibration is subsided, and after the vibration subsides, the element hologram is recorded.
[0046]
As described above, in this holographic stereogram creating system, a plurality of exposure images based on the image data generated by the image data generating unit 1 are sequentially displayed on the display device 41, and the shutter 32 is provided for each image. The images are released, and the respective images are sequentially recorded on the hologram recording medium 30 as strip-shaped element holograms. At this time, since the hologram recording medium 30 is sent by one element hologram for each image, each element hologram is continuously arranged in the horizontal direction. As a result, a plurality of images including lateral parallax information are recorded on the hologram recording medium 30 as a plurality of laterally continuous element holograms, and a holographic stereogram having lateral parallax is obtained.
[0047]
Next, the image data generator 1 of the holographic stereogram creating system as described above will be described in detail.
[0048]
The image data generating unit 1 includes a parallax image sequence photographing system that photographs a plurality of images serving as a source of a holographic stereogram, that is, a parallax image sequence.
[0049]
As shown in FIG. 3, the parallax image sequence photographing system includes a turntable 51 on which a subject 50 is placed, and a photographing device 52 arranged to face a rotation center of the turntable 51. Is fixed to face the subject 50, and the distance d between the subject 50 and the photographing device 52 is fixed. _v Is held substantially constant, and the subject 50 placed on the turntable 51 can be rotated.
[0050]
When a parallax image sequence is photographed by this parallax image sequence photographing system, the subject 50 is placed on the turntable 51, and every time the subject 50 is photographed by the photographing device 52, the turntable 51 is moved by a predetermined angle by an arrow in the figure. By rotating in a certain direction as shown in A1, a plurality of images with different viewpoints are captured. Thereby, a parallax image sequence having a horizontal parallax is obtained.
[0051]
Also, the distance d between the subject 50 and the photographing device 42 without moving the subject 50 _v Is held substantially constant, and the side of the photographing device 52 is rotated about the subject 50, a similar parallax image sequence can be obtained. At this time, as shown in FIG. 5, each time the subject 50 is photographed while the subject 50 is fixed, the photographing device 52 is held at a predetermined angle around the subject 50 while keeping the photographing device 52 facing the subject 50. However, by rotating in a certain direction as shown by an arrow A2 in the figure, many images with different viewpoints are taken.
[0052]
The method shown in FIG. 3 and the method shown in FIG. 4 are equivalent, and a similar parallax image sequence can be captured by either method. When the parallax image sequence is actually photographed, the viewpoint of the photographing device 52 with respect to the subject 50 is continuously changed by rotating the subject 50 or the photographing device 52 by a predetermined angle as described above. Approximately 1000 images are photographed.
[0053]
When the parallax image sequence is photographed by rotating the subject 50 or the photographing device 52 as described above, the angle of view θ of the photographing device 52 _v Does not need to be large, and may be set to such an extent that the subject 50 falls within the shooting range. Therefore, in this parallax image sequence photographing system, there is no need to widen the angle of view using a wide-angle lens, and photographing can be performed with an inexpensive photographing device. Also, the angle of view θ per screen _v Can be narrowed, so that the resolution of the image can be increased.
[0054]
Angle of view θ of photographing device _v Specifically, as shown in FIG. 5, the horizontal length of the holographic stereogram to be created is W and the vertical length is H, and the distance between the holographic stereogram to be created and the observer's viewpoint is Distance of d _v Is set as in the following equation (1).
[0055]
θ _v = 2 tan ^-1 (W / 2d _v …… (1)
In the parallax image sequence photographing system as described above, since the subject 50 or the photographing device 52 is rotated to photograph a plurality of images having different viewpoints, the subject 50 is larger than a method in which the photographing device 52 is moved in parallel. Also, the size of the entire parallax image sequence photographing system can be reduced. Also, the angle of view θ of the photographing device 52 _v Is small, a sufficient viewing angle in the horizontal direction can be obtained by rotating the subject 50 or the photographing device 52. In addition, since the subject 50 is always located in front of the photographing device 52 even if the photographing position moves, unnecessary portions where the subject 50 is not shown in the image of the parallax image sequence are hardly included. Therefore, useless image data is hardly included, which is very advantageous in terms of effective use of data.
[0056]
By the way, the photographed parallax image sequence is read as image data by an image data processing unit that processes image data, as described later. Specifically, in the present embodiment, the parallax image sequence is supplied to the image data processing unit as an NTSC video signal. Therefore, the photographing device 52 is preferably a photographing device that can directly output a photographed image as image data, such as a still camera or a video camera using a charge-coupled device (CCD: Charge Coupled Device) in the photosensitive section. is there. Note that a camera that records an image on a photosensitive film may be used as the photographing device 52. However, at this time, it is necessary to convert the image recorded on the photosensitive film into image data using an image reading device or the like.
[0057]
Here, the parallax image sequence is obtained by actually photographing the subject 50 with the parallax image sequence photographing system, but the parallax image sequence may be generated by a computer. That is, using a computer, a plurality of CAD (Computer Aided Design) images, CG (Computer Graphics) images, or the like may be sequentially created by sequentially giving parallax in the horizontal direction, and these images may be used as a parallax image sequence.
[0058]
The image data generation unit 1 includes an image data processing unit that reads a parallax image sequence as image data from the above-described parallax image sequence photographing system and performs predetermined image data processing.
[0059]
As shown in FIG. 6, the image data processing unit 60 includes an arithmetic processing unit 61 including a central processing unit (CPU) for performing image data processing and the like, and an internal storage device 62 provided for the arithmetic processing unit 61. It has. Here, the arithmetic processing unit 61 includes an input board capable of inputting an NTSC video signal at a full frame rate, and a compression / expansion board for compressing / expanding image data by the JPEG method. Here, the JPEG method is adopted as the image compression method, but it goes without saying that another image compression method may be adopted.
[0060]
The flow of image data processing in the image data processing unit 60 will be described with reference to the flowchart shown in FIG.
[0061]
When performing image data processing, first, in step ST1-1, a parallax image sequence is photographed by the parallax image sequence photographing system, and the image data of the parallax image sequence is input to the image data processing unit 60. Specifically, every time the subject 50 is photographed by the photographing device 52 of the parallax image sequence photographing system, the image data of the photographed image is output from the parallax image sequence photographing system as an NTSC video signal via the input board. The data is sequentially input to the arithmetic processing unit 61 of the image data processing unit 60. That is, in the image data generation unit 1 according to the present embodiment, while the subject 50 is photographed by the photographing device 52 of the parallax image sequence photographing system, the image data Enter image data.
[0062]
At this time, every time image data for one image is input, the image data input to the arithmetic processing unit 61 is subjected to data compression by a compression / decompression board provided in the arithmetic processing unit 61, and the compressed image data Is read into the internal storage device 62. Therefore, when the parallax image sequence photographing system completes capturing the parallax image sequence, all the image data obtained by compressing the image data of the parallax image sequence is read into the internal storage device 62. Here, the original image data of the parallax image sequence is an enormous amount of data. By compressing and reading the image data in this way, the image data of the enormous amount of the Can be read into the internal storage device 62.
[0063]
In the following image data processing, image data necessary for image data processing among the image data read into the internal storage device 62 is decompressed on the internal storage device 62 as needed. That is, in the present embodiment, image data processing is performed on the internal storage device 62 having a very high processing speed. Therefore, in this embodiment, image data processing can be performed at a very high speed. On the other hand, conventionally, the original image data is stored in an external storage device such as a hard disk drive, and image data processing is performed while accessing the external storage device. However, since an external storage device such as a hard disk drive has a low processing speed, image data processing requires a very long time.
[0064]
Next, in the state where the image data is read into the internal storage device 62 as described above, in step ST1-2, a predetermined image data conversion process is performed on the image data read into the internal storage device 62, Image data of one image to be recorded in the graphic stereogram is generated.
[0065]
In step ST1-2, first, in step ST1-2-1, image data necessary for image data conversion processing is selected from the image data read into the internal storage device, and the image data is converted by the compression / decompression board. Elongate. Next, in step ST1-2-2, image data conversion processing is performed based on the decompressed image data, and one image data D1 of an image to be recorded in the holographic stereogram is generated.
[0066]
In the image data conversion processing here, keystone distortion correction processing and viewpoint conversion processing, which will be described later, are performed. However, the viewpoint conversion processing requires a very large number of data accesses. Conventionally, image data of a parallax image sequence is stored in an external storage device, and image data conversion processing is performed while accessing the external storage device. For this reason, conventionally, this image data conversion process required a very long time. On the other hand, in the present embodiment, the image data of the parallax image sequence is compressed and read into the internal storage device 62, and the image data conversion process is performed on the internal storage device 62. Processing can be performed. The image data conversion processing here will be described later in detail.
[0067]
Next, in step ST1-3, the image data D1 generated in step ST1-2-2, that is, the image data D1 of the image to be recorded on the hologram recording medium 30, is displayed on the display device of the holographic stereogram printer device 3. 41, and an image based on the image data D1 is displayed on the display device 41 as an exposure image. At this time, a timing signal S1 indicating that the exposure image has been displayed on the display device 41 is transmitted from the image data generation unit 1 to the control computer 2.
[0068]
Here, when the control computer 2 receives the timing signal S1, it opens the shutter 32 of the holographic stereogram printer device 3 for a predetermined time to expose the hologram recording medium 30, and the holographic recording medium 30 is displayed on the display device 41. The image is recorded on the hologram recording medium as an element hologram. When the exposure is completed, the recording medium feed mechanism 43 is driven to feed the hologram recording medium 30 by one element hologram.
[0069]
That is, in the holographic stereogram creating system according to the present embodiment, the image data D1 is sent from the image data processing unit 60 to the display device 41, and an image based on the image data D1 is sent to the display device 41 as an exposure image. Each time the exposure image is displayed on the display device 41, a timing signal S1 indicating that the exposure image has been displayed is sent from the image data processing section 60 to the control computer 2 so that the display device 41 is displayed. The timing of image display on the hologram and the timing of exposure of the hologram recording medium 30 are synchronized. In other words, in this holographic stereogram creating system, processing relating to images is performed only by the parallax image sequence photographing system and the image data generating unit 1 including the image data processing unit 60, and the control computer 2 uses the holographic stereogram printer. Only the control of the device 3 is performed.
[0070]
Next, in step ST1-4, the image data D1 of the exposure image generated in step ST1-2-2, that is, the image data D1 of the image recorded on the hologram recording medium 30 is erased from the internal storage device 62. I do. As a result, image data unnecessary for the subsequent processing is deleted from the internal storage device 62, and a wide area in the internal recording device 62 is always secured. If necessary, the image data D1 generated in step 1-2-2 may be stored in an external storage device such as a hard disk device.
[0071]
Through the above steps, one image data of the image for exposure is generated from the image data of the original parallax image sequence, and an image based on the image data is recorded on the hologram recording medium as a one-element hologram.
[0072]
Next, in step ST1-5, it is determined whether all the element holograms have been created, that is, whether all the exposures to the hologram recording medium 30 have been completed. If the exposure has not been completed, the process returns to step ST1-2 to generate image data of the next image to be recorded on the hologram recording medium 30, and stores the next image in the hologram recording medium 30 as an element hologram. Record as Then, the above processing is repeated, and when all the exposures to the hologram recording medium 30 are completed, the processing is terminated.
[0073]
By the way, in the present embodiment, each time the timing signal S1 is sent from the image data processing unit 60 to the control computer 2, a one-element hologram is created. Therefore, the transmission interval of the timing signal S1 is set to be equal to or longer than the time until the vibration generated for feeding the hologram recording medium 30 by the recording medium feeding mechanism 43 stops. Thereby, the hologram recording medium 30 is exposed in a state where the vibration of the hologram recording medium 30 is reduced, and the image quality of the holographic stereogram to be created is improved.
[0074]
By performing image data processing on the internal storage device 62 as described above, it is not necessary to transfer image data having a large data amount to and from the external storage device, and the processing speed is greatly improved. Therefore, the time from the input of the disparity image sequence that is the source of the holographic stereogram to the completion of the holographic stereogram can be significantly reduced.
[0075]
Further, when the image data is processed while compressing and expanding the image data on the internal storage device 62 as described above, the processing time required for the image data conversion processing is greatly reduced. Therefore, even if the image data is further increased by achieving full color and high resolution, the image data conversion processing can be performed within a practical time.
[0076]
Moreover, since there is a margin in the processing time, it is possible to incorporate processing other than the viewpoint conversion processing described later as the image data conversion processing. Specifically, for example, image data conversion processing for color correction in a color hologram, image data conversion processing for lens aberration correction, and the like may be performed as image data conversion processing. Thereby, the image quality of the holographic stereogram can be further improved.
[0077]
Also, in general, when vibration occurs when creating a holographic stereogram, the diffraction efficiency of the holographic stereogram deteriorates. Therefore, when creating a holographic stereogram, anti-vibration measures are very important. . An external storage device such as a hard disk drive device used in the conventional image data conversion process involves mechanical operations, which causes vibration. However, the external storage device used in the image data conversion process according to the present embodiment is used. Generally, the internal storage device 62 does not generate vibration because the processing is performed only by an electrical operation. Therefore, in the present embodiment, a holographic stereogram excellent in diffraction efficiency can be created without generating vibrations due to the image data conversion processing.
[0078]
Further, the internal storage device 62 that does not involve a mechanical operation is far more durable than an external storage device such as a hard disk drive. Therefore, the durability of the system can be improved by performing the image data conversion processing in which a great number of data accesses are performed on the internal storage device 62.
[0079]
Next, the image data conversion processing performed by the image data processing unit 60 will be described in detail.
[0080]
In the present embodiment, keystone distortion correction processing is performed on the image data of each image captured by the parallax image sequence imaging system, and further, the viewpoint data is corrected for the keystone distortion correction image data. Is performed to convert the position of. Thereby, image data of an image to be recorded on the hologram recording medium 30 is generated.
[0081]
First, the keystone distortion correction processing will be described.
[0082]
In the present embodiment, as described above, the parallax image sequence is obtained by rotating the subject 50 or the photographing device 52. For this reason, when the photographing device 52 is located in front of the subject 50 as shown in FIG. 8A, the subject 54 shown in the photographed image 53 is distorted as shown in FIG. 8B. However, as shown in FIG. 9A, when the photographing device 52 is not located in front of the subject 50 as shown in FIG. 9A, as shown in FIG. Keystone distortion occurs. Therefore, in the present embodiment, this keystone distortion is corrected.
[0083]
As shown in FIG. 10, the correction of the keystone distortion is based on the case where the photographing device 52 is located in front of the subject 50, and the rotation angle when the subject 50 or the photographing device 52 is rotated is θ. The distance between the rotation center 50a of the subject 50 or the photographing device 52 and the viewpoint position 52a of the photographing device 52 is represented by d. _v And the angle of view in the horizontal direction of the photographing device 52 is θ _v Can be realized by performing enlargement or reduction processing for each vertical line of the image at the ratio defined by the following equation (2).
[0084]
(Equation 1)

[0085]
However, in the above equation (2), α is, as shown in FIG. 10, an imaginary line connecting the rotation center 50 a of the subject 50 or the imaging device 52 and the viewpoint position 52 a of the imaging device 52 is La, and The angle between the virtual line La and the virtual line Lb is shown when a virtual line connecting the image position Pa to be processed and the viewpoint position 52a of the imaging device 52 is Lb.
[0086]
By performing the keystone distortion correction processing on the image data of each image in this manner, the image data of the parallax image sequence becomes the same as the image data obtained when the imaging device 52 is moved in parallel. Therefore, by correcting the keystone distortion in this way, when a planar holographic stereogram is created, the image is not disturbed due to the keystone distortion.
[0087]
The flow of the keystone distortion correction processing as described above will be described in detail.
[0088]
Here, each image of the parallax image sequence has a plurality of pixels in a horizontal direction as a parallax direction and a vertical direction as a non-parallax direction. Specifically, for example, as shown in FIG. 11, each image has 480 [pixels] in the horizontal direction and 640 [pixels] in the vertical direction. At this time, one image has a pixel row g in which pixels of 640 [pixels] are arranged in the vertical direction by 480 [pixels] in the horizontal direction.
[0089]
Then, when correcting the keystone distortion, as shown in FIG. 12, first, in step ST2-1, the angles α corresponding to the respective pixel rows g constituting the image to be corrected for the keystone distortion are calculated. I do.
[0090]
Next, in step ST2-2, the ratio ratio corresponding to the pixel row g is calculated for one pixel row g based on the above equation (2).
[0091]
Next, in step ST2-3, based on the ratio ratio calculated in step ST2-2, enlargement or reduction processing is performed on the image based on the pixel row g to correct the keystone distortion of the image based on the pixel row g. I do.
[0092]
At this time, the light receiving surface of the photographing device 52 that has photographed the original image and the exposure surface of the hologram recording medium 30 are parallel to each other, that is, the original image photographed by the photographing device 52 is The coordinate conversion of the image data is performed so that the images recorded on the hologram recording medium 30 are parallel to each other.
[0093]
In this coordinate conversion, as shown in FIG. 10, a coordinate position x ′ of the original image photographed by the photographing device 52 and a coordinate position x of the image recorded on the hologram recording medium 30 are set, and the hologram recording is performed. For a plurality of points sampled at equal intervals on the image recorded on the medium 30, α represented by the following equation (3) is calculated.
[0094]
(Equation 2)

[0095]
Then, the coordinate position x ′ of the original image corresponding to the coordinate position x of the image recorded on the hologram recording medium 30 is calculated from the following equation (4) from α calculated by the above equation (3).
[0096]
x '= d _v ・ Tanα (4)
From the above equations (3) and (4), the relationship between the coordinate position x ′ of the original image and the coordinate position x of the image recorded on the hologram recording medium 30 becomes clear. Therefore, coordinate conversion is performed based on the above equations (3) and (4), and the image data is recorded so that the image recorded on the hologram recording medium 30 is parallel to the hologram recording medium 30. Perform mapping. In the actual calculation, d _v , X, and x ′ are made to correspond to each pixel constituting the image data.
[0097]
Next, in step ST2-4, it is determined whether the correction of the keystone distortion has been completed for all the pixel rows g. When there is a pixel row g for which the correction of the keystone distortion has not been completed, the process returns to step ST2-2, and the keystone distortion is corrected for the pixel row g for which the correction of the keystone distortion has not been completed.
[0098]
On the other hand, when there is no pixel row g for which the correction of the keystone distortion has not been completed and the correction of the keystone distortion has been completed for all the pixel rows g, the process proceeds to step ST2-5.
[0099]
In step ST2-5, it is determined whether the correction of the keystone distortion has been completed for all the images. If there is an image for which the correction of the keystone distortion has not been completed, the process returns to step ST2-1 to correct the keystone distortion for the image for which the correction of the keystone distortion has not been completed.
[0100]
With the above processing, the correction processing of the keystone distortion is completed for all the images constituting the parallax image sequence.
[0101]
Note that the timing for performing the above-described keystone distortion correction processing may be performed any time before the viewpoint conversion processing described later. That is, the correction of the keystone distortion may be performed every time one image data of one image is input to the image data processing unit 60 from the parallax image sequence photographing system, or may be corrected from the parallax image sequence photographing system. The processing may be performed after image data of all images constituting the parallax image sequence is input to the image data processing unit 60.
[0102]
Next, the viewpoint conversion processing performed on the image data on which the keystone distortion correction processing has been performed as described above will be described.
[0103]
In the holographic stereogram, the positional relationship between the viewpoint of the photographing device 52 and the subject 50 at the time of photographing is also held for the created reproduced image of the holographic stereogram, and thus the image of the photographed parallax image sequence When a holographic stereogram is created using the data as it is, the reproduced image 60 is formed deeper than the hologram surface Ha of the holographic stereogram H, as shown in FIG. Therefore, in such a holographic stereogram H, the distance d between the reproduced image 60 and the viewpoint 61 is _v0 Is the distance d from the center of the subject 50 to the viewpoint of the photographing device 52 at the time of photographing. _v If the viewpoint 61 is not viewed on the hologram surface Ha during observation, the reproduced image 60 will be distorted so that
[0104]
Further, in particular, in a white reproduction holographic stereogram reproduced by white light, the reproduction image 60 is more blurred as the image formation position of the reproduction image 60 is farther from the hologram surface Ha. If the image is formed deeper than the hologram surface Ha, the reproduced image 60 is blurred.
[0105]
Therefore, in order to solve these problems, a viewpoint conversion process is performed on the original image data so that the reproduced image 62 is formed near the hologram surface Ha of the holographic stereogram H as shown in FIG. To As a result, even if the viewpoint 63 is placed at a position distant from the hologram surface Ha, a reproduced image 62 without distortion or blur can be obtained.
[0106]
In this viewpoint conversion processing, mapping of the image in the horizontal parallax direction is performed based on the relationship between the viewpoint position of the image at the time of generating the parallax image sequence and the viewpoint position of the image at the time of hologram exposure. Image data of an image corresponding to 63 is generated. That is, in the viewpoint conversion process, the order of the pixel array g, which is the data of the vertical slit-shaped image, is exchanged with respect to the image data of the plurality of images of the parallax image array, and thereby, a new viewpoint position is converted. Reconstruct image data.
[0107]
Prior to the detailed description of the viewpoint conversion process, a parallax image sequence that is a source of the viewpoint conversion process will be described with reference to FIG.
[0108]
In FIG. 15, H indicates a holographic stereogram, and e ₁ , E ₂ , ..., e _n-1 , E _n Indicates the exposure position of the element hologram, W indicates the horizontal length of the holographic stereogram H, and d indicates _v Indicates the distance from the center of the subject 50 to the viewpoint of the imaging device 52. Also, v ₁ , V ₂ , ..., v _n-1 , V _n Indicates the viewpoint position of the image capturing device 52 when capturing a parallax image sequence, and θ _v Indicates the angle of view at the time of shooting, and P ₁ , P ₂ , ..., P _n-1 , P _n Indicates each image of the captured parallax image sequence, and Q ₁ , Q ₂ , ..., Q _n-1 , Q _n Indicates an image to which keystone distortion has been corrected.
[0109]
As shown in FIG. 15, a plurality of images P ₁ , P ₂ , ..., P _n-1 , P _n Is a viewpoint V ₁ To V _n The period up to is obtained by rotating the photographing device 52 at the same curvature and sequentially photographing. And these images P ₁ , P ₂ , ..., P _n-1 , P _n By correcting the keystone distortion as described above, the image Q in which the keystone distortion has been corrected ₁ , Q ₂ , ..., Q _n-1 , Q _n Is obtained. In the viewpoint conversion process, the image Q in which the keystone distortion has been corrected ₁ , Q ₂ , ..., Q _n-1 , Q _n To generate new image data subjected to viewpoint conversion.
[0110]
Here, when the center of the holographic stereogram H is the origin, the horizontal direction parallel to the holographic stereogram H is the X axis, and the direction perpendicular to the holographic stereogram H and orthogonal to the X axis is the Z axis, v ₁ Coordinates (x ₁ , Z ₁ ) Is set as shown in the following equation (5), and the viewpoint v _n Coordinates (x _n , Z _n ) Is set as shown in the following equation (6). As a result, a parallax image sequence required for a viewpoint conversion process described later is obtained.
[0111]
(Equation 3)

[0112]
By the way, as shown in FIG. ₁ , P ₂ , ..., P _n-1 , P _n Viewpoint position v ₁ , V ₂ , ..., v _n-1 , V _n Are moving in an arc shape. This is the image Q with the keystone distortion corrected. ₁ , Q ₂ , ..., Q _n-1 , Q _n The same applies to these images Q ₁ , Q ₂ , ..., Q _n-1 , Q _n Is also moving in an arc shape. As described above, if the parallax image sequence in which the viewpoint position is moved in an arc shape is recorded on the flat hologram recording medium as it is, the reproduced image is distorted. Therefore, when the viewpoint position is changed so that the reproduced image is formed on the hologram surface, the conversion is performed so that the viewpoint position moves in parallel with the hologram surface.
[0113]
Hereinafter, the viewpoint conversion process will be described with reference to FIG. 16 showing a state of the viewpoint conversion process and a flowchart of FIG. 17 showing a flow of the viewpoint conversion.
[0114]
In FIG. 16, the exposure position e of the element hologram is calculated from the original parallax image sequence. _m Exposure image R corresponding to _m Of the image data of the element hologram. ₁ , E ₂ , ..., e _n-1 , E _n Exposure image R corresponding to ₁ , R ₂ , ..., R _n-1 , R _n Are respectively reconstructed. Specifically, the number of element holograms is about 500, and the image data of the exposure image is reconstructed by these numbers. However, the number of element holograms is determined by the size of the holographic stereogram to be created and the exposure pitch of the element holograms. Naturally, the number of element holograms is not limited to 500.
[0115]
In the following description, it is assumed that each image has 480 [pixels] in the horizontal direction and 640 [pixels] in the vertical direction. That is, in this viewpoint conversion processing, the image Q in which the keystone distortion has been corrected is ₁ , Q ₂ , ..., Q _n-1 , Q _n Therefore, image data of an image having 480 [pixels] in the horizontal direction and 640 [pixels] in the vertical direction is generated for the element hologram.
[0116]
When performing the viewpoint conversion process, as shown in FIG. 17, first, in step ST3-1, the image for exposure R is divided into pixel columns corresponding to the resolution in the horizontal direction, and the division corresponding to each pixel column is performed. Set the point rm. Here, the image for exposure R _m Has 480 [pixels] pixels in the horizontal direction, the exposure image is divided into 480 slit-like pixel columns, and 480 division points r corresponding to the respective pixel columns are set. At this time, each pixel column has 1 [pixel] pixels in the horizontal direction and 640 [pixel] pixels in the vertical direction.
[0117]
Next, in ST3-2, one of the division points r set in step ST3-1 is selected, and the division point r and the exposure position e of the element hologram are selected. _m Virtual line k connecting ₁ Is defined. At this time, the exposure image R _m And the distance d between the holographic stereogram H _v1 Is the arc V through which the viewpoint of the original parallax image sequence passes _path Of the image for exposure θ _ev Is the angle of view θ of the cylindrical lens 42 for focusing the object light on the hologram recording medium 30 shown in FIG. _s To match.
[0118]
Next, in ST3-3, the virtual line k defined in step ST3-2 ₁ And the arc V through which the viewpoint of the original parallax image sequence passes _path Is calculated.
[0119]
Next, in ST3-4, from the viewpoint positions of the image in which the keystone distortion has been corrected, the viewpoint position v closest to the intersection calculated in step ST3-3. _m To explore.
[0120]
Next, in ST3-5, the viewpoint position V searched in step ST3-4 from the image in which the keystone distortion has been corrected. _m Image Q from the viewpoint _m Select
[0121]
Next, in ST3-6, the viewpoint position v searched in step ST3-4. _m And the exposure position e of the element hologram _m Virtual line k connecting ₂ Is defined.
[0122]
Next, in ST3-7, the virtual line k defined in step ST3-6 ₂ And the image Q selected in step ST3-5. _m Intersection j with _m Is calculated.
[0123]
Next, in ST3-8, the image Q selected in step ST3-5 _m From the pixel rows constituting the intersection j calculated in step ST3-7. _m Is selected, and the selected pixel row is referred to as an exposure image R. _m Is mapped to the pixel column corresponding to the division point r.
[0124]
That is, in the pixel row of the image in which the keystone distortion has been corrected, the intersection j indicated by ■ _m Is located on the exposure image R. _m Is mapped to the position indicated by ●.
[0125]
Next, in ST3-9, it is determined whether the mapping of the pixel columns has been completed for all the division points r. If the mapping has not been completed for all the division points r, the process returns to step ST3-2, and the pixel columns are mapped for the division points r for which the mapping has not been completed.
[0126]
By the above processing, one exposure image R _m Is completed for one exposure image R _m Are reconstructed and generated.
[0127]
Then, this viewpoint conversion process is performed by exposing each element hologram to the exposure position e. ₁ , E ₂ , ..., e _n-1 , E _n The exposure image R is repeated by the number of the element holograms. ₁ , R ₂ , ..., R _n-1 , R _n Is reconstructed. As a result, the viewpoint position is converted so that the reproduced image is formed on the hologram surface, and the image data of the parallax image sequence in which the viewpoint position moves parallel to the hologram surface is generated.
[0128]
By the way, the viewpoint conversion processing is realized by exchanging pixel columns and generating new image data. The order of the replacement is the same even if the parallax image sequence is different, as long as the parameters of the viewpoint conversion process are the same. Therefore, if the viewpoint and the like of the original parallax image sequence are the same in the viewpoint conversion process, it is not necessary to repeat the above calculation, and data recording the order of replacement of the pixel sequences is prepared. Alternatively, the pixel rows may be replaced with reference to the data.
[0129]
That is, only for the first time, the viewpoint conversion process is performed in accordance with the flow shown in FIG. 17, and at this time, the correspondence between the pixel row of the original image and the pixel row of the exposure image is obtained, and the correspondence is determined by the hard disk drive. Or the like, and the viewpoint conversion process may be performed based on this correspondence in the next and subsequent viewpoint conversion processes. Thereby, the repetition of the calculation process is eliminated, and the processing speed can be greatly improved.
[0130]
As described above, the keystone distortion correction processing and the viewpoint conversion processing are performed, the image data of the parallax image sequence is reconstructed, and the holographic stereogram is created using the reconstructed image data, thereby reproducing the image. It is possible to create a planar holographic stereogram in which an image is formed on the hologram surface without distortion.
[0131]
That is, in the holographic stereogram created based on such image data, the viewpoint position information is corrected for the parallax in the horizontal direction by the keystone distortion correction process and the viewpoint conversion process. In the vertical direction, the information at the time of capturing the parallax image is stored as it is. Therefore, in the holographic stereogram created based on such image data, the viewpoint is moved in an arc shape, as in the case of the movement of the viewpoint of the photographing apparatus at the time of photographing, so that the holographic stereogram is reproduced without distortion near the hologram surface. The reproduced image to be reproduced can be observed.
[0132]
【The invention's effect】
As is clear from the above description, according to the present invention, even if the subject is large, the parallax image sequence photographing system for obtaining the parallax image sequence can be downsized. Moreover, since it is not necessary to increase the angle of view of the photographing device, it is not necessary to use a special lens such as a wide-angle lens, and the cost of the photographing device can be reduced.
[0133]
Further, according to the present invention, since useless image data can be reduced, the data can be used effectively. Therefore, for example, when the same amount of image data is handled, the image quality of the holographic stereogram can be improved as compared with the related art.
[0134]
In addition, in the present invention, the keystone distortion correction processing is performed on the image data of a plurality of captured images, so that the image data generated by the image data generating method according to the present invention requires a planar holographic image. Stereograms can be created.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of a holographic stereogram creating system.
FIG. 2 is a diagram illustrating a configuration example of an optical system of a holographic stereogram printer device.
FIG. 3 is a schematic diagram illustrating an example of a parallax image sequence photographing system.
FIG. 4 is a schematic diagram illustrating another example of a parallax image sequence photographing system.
FIG. 5 is a diagram showing a relationship between a holographic stereogram and an angle of view of a photographing device.
FIG. 6 is a block diagram illustrating a configuration example of an image data processing unit.
FIG. 7 is a flowchart of image data processing.
FIG. 8 is a diagram illustrating a state of shooting when a shooting device is positioned in front of a subject, and a shot image.
FIG. 9 is a diagram illustrating a state of shooting when the shooting device is not located in front of the subject and a shot image.
FIG. 10 is a diagram illustrating parameters used for a keystone distortion correction process.
FIG. 11 is a diagram illustrating an example of an image forming a parallax image sequence.
FIG. 12 is a flowchart of a keystone distortion correction process.
FIG. 13 is a schematic diagram showing a state in which a reproduced image from a holographic stereogram created without performing a viewpoint conversion process is observed.
FIG. 14 is a schematic diagram showing a state in which a reproduced image from a holographic stereogram created after performing a viewpoint conversion process is observed.
FIG. 15 is a diagram illustrating a positional relationship between a parallax image sequence as a source of a viewpoint conversion process and a holographic stereogram.
FIG. 16 is a diagram illustrating a viewpoint conversion process.
FIG. 17 is a flowchart of a viewpoint conversion process.
FIG. 18 is a schematic diagram showing a method for creating a holographic stereogram.
FIG. 19 is a diagram illustrating an example of a conventional parallax image sequence photographing method.
FIG. 20 is a diagram illustrating another example of a conventional parallax image sequence photographing method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image data generation part, 2 Control computer, 3 Holographic stereogram printer device, 50 subject, 51 turntable, 52 imaging device

Claims (10)

By rotating the subject or the photographing device while maintaining the distance between the subject and the photographing device substantially constant, a plurality of images having different viewpoints are photographed by the photographing device,
Performs keystone distortion correction processing on image data of a plurality of captured images,
An image characterized by performing a viewpoint conversion process for converting a viewpoint position on image data subjected to a keystone distortion correction process, and generating image data of an image to be recorded in a planar holographic stereogram. Data generation method. By rotating the subject or the imaging device, a plurality of images with different viewpoints are captured by the imaging device,
  A ratio corresponding to a pixel row arranged in the vertical direction of the image data of a plurality of captured images and a ratio based on when the imaging device is located in front of the subject is obtained,
  Performing keystone distortion correction processing by performing enlargement or reduction processing for each vertical line of the image based on the ratio,
  Performs viewpoint conversion processing to convert the position of the viewpoint on the image data that has been subjected to the keystone distortion correction processing,
  An image data generating method, which generates image data of an image to be recorded on a planar holographic stereogram. The keystone distortion correction process described above
  At least the rotation angle by the rotation of the imaging device based on when the imaging device is located in front of the subject, and the coordinate position of the image in which the holographic stereogram is recorded, and the imaging device and the viewpoint position Find the ratio for each vertical line according to the distance of
  2. The image data generation method according to claim 1, wherein the enlargement or reduction processing is performed on each vertical line of the image according to the ratio. By rotating the subject or the imaging device in the horizontal direction with respect to the screen, a plurality of images with different viewpoints are captured by the imaging device,
The rotation angle due to the rotation of the imaging device with respect to the time when the imaging device is located in front of the subject, and the coordinate position of the image in which the holographic stereogram is recorded, and the relationship between the imaging device and the viewpoint position According to the distance, find the ratio for each vertical line,
Enlarge or reduce each vertical line of the image according to the above ratio,
For the image data on which the above-mentioned enlargement or reduction processing has been performed, a viewpoint conversion processing for converting the position of the viewpoint is performed.
An image data generating method, which generates image data of an image to be recorded on a planar holographic stereogram . The method according to claim 1, wherein, when photographing the subject, the subject is placed on a turntable, and each time the subject is photographed, the turntable is rotated by a predetermined angle to photograph a plurality of images having different viewpoints . The image data generation method according to claim 3 . When photographing an object, for each photographing an object, by rotating the predetermined angle imaging apparatus as substantially around the object, claim 1, characterized in that to shoot a plurality of images having different viewpoints, wherein The image data generation method according to claim 3 or 4 . At the time of performing the viewpoint conversion processing, the data constituting the image subjected to the keystone distortion correction processing is replaced with data for each pixel row, and a reproduced image is formed near the holographic plane of the holographic stereogram. 5. The image data generating method according to claim 1, wherein the image data of the image to be recorded on the holographic stereogram is generated.   Image data of a plurality of images of different viewpoints taken by rotating the subject or the imaging device while maintaining the distance between the subject and the imaging device substantially constant is input, and the image data of the plurality of input images is input. Keystone distortion correction means for performing keystone distortion correction processing;
  A viewpoint that converts the position of the viewpoint for image data that has undergone keystone distortion correction processing Viewpoint conversion means for performing conversion processing and generating image data of an image to be recorded in a planar holographic stereogram;
  An image data generation device comprising: Image data of a plurality of images having different viewpoints taken by rotating the subject or the imaging device is input, and the image data of the input plurality of images corresponds to a pixel row aligned in the vertical direction, and is located in front of the subject. Image processing means for obtaining a ratio based on when the imaging device is located, performing keystone distortion correction processing by performing enlargement or reduction processing for each vertical line of the image based on the ratio,
  Viewpoint conversion means for performing viewpoint conversion processing for converting the position of the viewpoint on the image data subjected to the keystone distortion correction processing, and generating image data of an image to be recorded in a planar holographic stereogram;
  An image data generation device comprising: When image data of a plurality of images of different viewpoints taken by rotating the subject or the imaging device in the horizontal direction with respect to the screen is input, and when the imaging device is positioned in front of the subject, According to the rotation angle by the rotation of the imaging device, and the coordinate position of the image where the holographic stereogram is recorded, and the distance between the imaging device and the viewpoint position, the ratio is obtained for each vertical line, and according to the ratio, Image processing means for performing enlargement or reduction processing on each vertical line of the image,
  Viewpoint conversion means for performing viewpoint conversion processing for converting the position of the viewpoint on the image data subjected to the enlargement or reduction processing, and generating image data of an image to be recorded on a planar holographic stereogram;
  An image data generation device comprising:

Images