JP4082166B2 - Photodetection device, projector, photodetection method, program, and recording medium - Google Patents

Description

で定義されるサンプルスクリーン特性ベクトルＰnを計算し、Ｐn保存部６０ｃに保存する（Ｓ１６）。
【００３８】
プロジェクタ用マトリックスＭdnの生成処理
次に、図５を参照して、プロジェクタ用マトリックスＭdnの生成処理について説明する。
【００３９】
まず、Ｍdn計算部６０ｄは、ＬＭＳ／ＸＹＺ対記録部６０ａに記録されるデータに基づき、各スクリーンに対するプロジェクタ用マトリックスＭdn：
【００４０】
【数２】

を求め（Ｓ２０）、Ｐn保存部６０ｃに保存する（Ｓ２４）。
【００４１】
標準センサによる照明光の測定処理
次に、図６を参照して、本発明の一実施形態にかかる標準センサによる照明光の測定処理を説明する。
【００４２】
図６に示すように、数種類のサンプルスクリーン上に各種照明光を照射し（Ｓ３０）、標準センサ７５によってＬＭＳ値を測定するとともに、三刺激値を測定可能な輝度計７０によってＸＹＺ値を測定する（Ｓ３２）。照明光としては、白熱灯、白色蛍光灯（色温度4000Ｋ程度）、昼白色蛍光灯（色温度5000Ｋ程度）など、使用環境でよく用いられるものを選択する。
【００４３】
なお、プロジェクタ光の測定処理と同様に、サンプルスクリーンの色は、光センサ６０で測定可能にしたいスクリーンの色の範囲内で可能な限り均等に選択することが好ましい。また、サンプルスクリーンの数は多いほど変換精度が高くなるが、一方、計算量は多くなってしまうので、６〜９種類程度が適当である。
【００４４】
そして、Ｓ３２における測定によって、各スクリーンおよび各照明光に対する、輝度計７０によって測定される正しいＸＹＺ値と、標準センサ７５からの出力電圧（ＬＭＳ）とのデータ対が得られ、これらの対応関係がＬＭＳ／ＸＹＺ対記録部６０ａに記録される（Ｓ３４）。ＬＭＳ／ＸＹＺ対記録部６０ａに記録されるデータの一例は以下のとおりである。
【００４５】
測色する照明が照明αのときの標準センサでの測定値を(L_{α n},M_{α n},S_{α n})とし、輝度計での測定値を(X_{α n},Y_{α n},Z_{α n})とする。
【００４６】
測色する照明が照明βのときの標準センサでの測定値を(L_{β n},M_{β n},S_{β n})とし、輝度計での測定値を(X_{β n},Y_{β n},Z_{β n})とする。
【００４７】
測色する照明が照明γのときの標準センサでの測定値を(L_{γ n},M_{γ n},S_{γ n})とし、輝度計での測定値を(X_{γ n},Y_{γ n},Z_{γ n})とする。
【００４８】
ここで、ｎは0,1,2,…,Nであり、スクリーンの種類を表す。
【００４９】
照明用マトリックスＭinの生成処理
次に、図７を参照して、照明用マトリックスＭinの生成処理について説明する。
【００５０】
まず、Ｍin計算部６０ｆは、ＬＭＳ／ＸＹＺ対記録部６０ａに記録されるデータに基づき、各スクリーンに対する照明用マトリックスＭin：
【００５１】
【数３】

を求め（Ｓ４０）、Ｍin保存部６０ｆに保存する（Ｓ４２）。
【００５２】
プロジェクタ毎の付属センサ６０ｈによるプロジェクタ光の測定処理
次に、図８を参照して、プロジェクタ毎の付属センサ６０ｈによるプロジェクタ光の測定処理を説明する。当該処理は、付属センサの個体差を補正するために、各機体毎にキャリブレーション用のマトリックスを生成するために行う。
【００５３】
図８に示すように、まず、各機体について、暗室下において、基準スクリーン上に表示装置（プロジェクタ）のＲ(赤)Ｇ(緑)Ｂ(青)３色を照射し（Ｓ５０）、付属センサ６０ｈによってＬＭＳ値を測定する（Ｓ５２）。Ｓ５２における測定データの一例は以下のとおりである。
【００５４】
測色する色が赤(R,G,B)＝(255,0,0)のときの付属センサでの測定値を(L_R0',M_R0',S_R0')とする。
【００５５】
測色する色が緑(R,G,B)＝(0,255,0)のときの付属センサでの測定値を(L_G0',M_{G 0}',S_G0')とする。
【００５６】
測色する色が青(R,G,B)＝(0,0,255)のときの付属センサでの測定値を(L_B0',M_B0',S_B0')とする。
【００５７】
そして、Ｍo計算部６０ｉは、以下の式(3)を用いて、
【００５８】
【数４】

標準センサの測定値と各機体の付属センサでの測定値に基づき、キャリブレーション用マトリックスＭoを求め（Ｓ５４）、Ｍo保存部６０ｊに保存する（Ｓ５６）。
【００５９】
使用環境下での光測定処理
図１０に、使用環境下における光測定処理を行う光センサ６０の機能ブロック図を示す。
【００６０】
図１０に示す光センサ６０は、測定対象光のＬＭＳ値を測定する付属センサ６０ｈと、Ｍo保存部６０ｊに保存されているキャリブレーション用マトリックスＭoを用いてキャリブレーションを行うキャリブレーション部６０Ｋと、キャリブレーション後のセンサ出力をプロジェクタ光成分と照明光成分とに分離する光分離手段６０ｍと、使用環境下でのスクリーン特性ベクトルＰと、サンプルスクリーン特性ベクトルPnとの相関係数P(n)を求める相関係数P(n)計算部６０ｎと、相関係数P(n)から使用環境下でのマトリックスを合成するための重み付け係数Ｗnを求めるＷn計算部６０ｐと、プロジェクタ用マトリックスＭdnと重み付け係数Ｗnとから使用環境下におけるプロジェクタ用マトリックスＭdを合成するＭd合成部６０ｑと、照明光用マトリックスＭinと重み付け係数Ｗnとから使用環境下における照明光用マトリックスＭiを合成するＭi合成部６０ｒと、プロジェクタ光成分をプロジェクタ用マトリックスＭdを用いてＬＭＳ値からＸＹＺ値に変換するプロジェクタ光成分変換部６０ｓと、照明光成分を照明光用マトリックスＭiを用いてＬＭＳ値からＸＹＺ値に変換する照明光成分変換部６０ｔと、プロジェクタ光変換部６０ｓによって変換されたＸＹＺ値と、照明光成分変換部６０ｔによって変換されたＸＹＺ値とを和演算することによって使用環境下におけるプロジェクタのＲＧＢの三刺激値ＸＹＺを求める合成部６０ｕと、を備えて構成される。
【００６１】
次に、図９を参照して、使用環境下における光センサ６０による光測定処理を説明する。
【００６２】
ここで説明する光センサ６０における光測定処理は、光センサ６０のプログラム格納部（図示せず）に記録されたプログラムを実行することによって行われる。前記プログラム格納部は、プログラムを記録した媒体を構成する。さらに、当該処理プログラム自体も、本願発明の範囲内に包含される。
【００６３】
図９に示すように、使用環境下（照明あり、任意のスクリーン）において、表示装置（プロジェクタ）のＲ(赤)Ｇ(緑)Ｂ(青)Ｋ(黒)の４色を照射し（Ｓ６０）、付属センサ６０ｈによってＬＭＳ値を測定する（Ｓ６２）。Ｓ６２における測定データの一例は以下のとおりである。
【００６４】
測色する色が赤(R,G,B)＝(255,0,0)のときの付属センサでの測定値を(L_R',M_R',S_R')とする。
【００６５】
測色する色が緑(R,G,B)＝(0,255,0)のときの付属センサでの測定値を(L_G',M_G',S_G')とする。
【００６６】
測色する色が青(R,G,B)＝(0,0,255)のときの付属センサでの測定値を(L_B',M_B',S_B')とする。
【００６７】
測色する色が黒(R,G,B)＝(0,0,0)のときの付属センサでの測定値を(L_K',M_K',S_K')とする。
【００６８】
そして、キャリブレーション部６０Ｋは、Ｍo保存部６０ｊに保存されているキャリブレーション用マトリックスＭoを用いて、以下の式(4)のように、
【００６９】
【数５】

キャリブレーションを行う（Ｓ６４）。
【００７０】
L_G',M_G',S_G'、L_B',M_B',S_B'およびL_K',M_K',S_K'に関しても同様にキャリブレーションを行う。
【００７１】
そして、光分離手段６０ｍは、Ｓ６４で求めたキャリブレーション後のセンサ出力を、プロジェクタ光成分と照明光成分とに分離する（Ｓ６６）。
【００７２】
具体的には、Ｓ６６において、表示装置でＫ（黒）を出力したときのセンサ出力値Ｌ_KＭ_KＳ_Kは、表示装置の黒の出力と照明光との和と考えられるので、プロジェクタ光成分は、
Ｌ_R−Ｌ_K,Ｍ_R−Ｍ_K,Ｓ_R−Ｓ_K
Ｌ_G−Ｌ_K,Ｍ_G−Ｍ_K,Ｓ_G−Ｓ_K
Ｌ_B−Ｌ_K,Ｍ_B−Ｍ_K,Ｓ_B−Ｓ_K
となり、照明光成分は、
Ｌ_K,Ｍ_K,Ｓ_K
となる。
【００７３】
このようにして、プロジェクタ光成分と照明光成分とが分離される。
【００７４】
一方、相関係数P(n)計算部６０ｎは、使用環境におけるスクリーン特性を調べるために、使用環境下でのスクリーン特性ベクトルＰと、サンプルスクリーン特性ベクトルPnとの相関係数P(n)を求める（Ｓ６８およびＳ７０）。ここで、使用環境下でのスクリーン特性ベクトルＰは、
【００７５】
【数６】

によって定義され、相関係数P(n)は

と定義される。ここで、nは０〜Ｎの整数であり、スクリーンの種類を表す。
【００７６】
このように、前記スクリーン特性ベクトルＰは、表示装置のＲを光検出部の長波長用チャネルで測定した値と、表示装置のＧを光検出部の中波長用チャネルで測定した値と、表示装置のＢを光検出部の短波長用チャネルで測定した値と、を成分とするベクトルであり、相関係数P(n)は、２つの特性ベクトルの内積を変数とする関数である。
【００７７】
使用するスクリーンがサンプルスクリーンと同一であればP(n)＝１であり、使用するスクリーンがサンプルスクリーンと全く相関がなければP(n)＝０となる。
【００７８】
すなわち、複数のサンプルスクリーンについての測定結果と、使用しているスクリーンについての測定結果とに基づき、サンプルスクリーンと使用しているスクリーンとの相関度を示す相関係数を求める。そして、当該相関係数に基づき、使用しているスクリーンがどのサンプルスクリーンと相関度が強いか否かに応じて重み付けを行うことによって、プロジェクタ用マトリックスＭdnおよび照明用マトリックスＭinの合成を行う。
【００７９】
そして、Ｗn計算部６０ｐは、Ｓ７０で求めた相関係数P(n)から、使用環境下でのマトリックスを合成するための重み付け係数Ｗnを求める（Ｓ７２）。重み付け係数Ｗnは、
Ｗn＝Ｑn／(Ｑ₀＋Ｑ₁＋Ｑ₂＋ ・・・ ＋Ｑ_N)
によって定義される。重み付け係数Ｗnの求め方には以下の２例がある。
【００８０】
第１例
第１例は、
Ｑn＝１／(1001−1000Ｐn)
とする場合である。図１１に、重み付け係数Ｗnを求める第１例の場合のＰnとＱnとの関係を示す図を示す。
【００８１】
第２例
第２の例は、

とする場合である。図１２に、重み付け係数Ｗnを求める第２例の場合のＰnとＱnとの関係を示す図を示す。当該例で、Ｐ'は約0.98とするが、サンプルスクリーンの選択の仕方によってＰ'の値は異なる。
【００８２】
第１例の方が変換精度が期待できるため、変数のサイズなどに支障がなければ第１例を用いることが好ましい。第２例の方は、計算が第１例よりも簡単になるが、閾値Ｐ'を決める必要がある。閾値Ｐ'はサンプルスクリーンの選び方によって最適値が異なってくるが、おおむねＰ'＝0.98前後の値が適当である。下式のＷnおよびＱnとも、０〜1の範囲の値をとる。
【００８３】
次に、Ｍd合成部６０ｑは、Ｍdn保存部６０ｅに保存されているプロジェクタ用マトリックスＭdnと、Ｗn計算部６０ｐで計算された重み付け係数Ｗnとから、以下の式：

に従って、使用環境下におけるプロジェクタ用マトリックスＭdを合成する（Ｓ７４）。
【００８４】
そして、同様に、Ｍi合成部６０ｒは、Ｍin保存部６０ｇに保存されている照明光用マトリックスＭinと、Ｗn計算部６０ｐで計算された重み付け係数Ｗnとから、以下の式：

に従って、使用環境下における照明光用マトリックスＭiを合成する（Ｓ７６）。
【００８５】
そして、プロジェクタ光成分変換部６０ｓは、光分離手段６０ｍによって分離されたプロジェクタ光成分を、Ｓ７４において生成されたプロジェクタ用マトリックスＭdを用いて、以下の式(5)より、
【００８６】
【数７】

ＬＭＳ値からＸＹＺ値に変換する（Ｓ７８）。(L_G−L_K,M_G−M_K,S_G−S_K)および(L_Ｂ−L_K,M_Ｂ−M_K,S_Ｂ−S_K)についても同様である。
【００８７】
また、照明光成分変換部６０ｔは、光分離手段６０ｍによって分離された照明光成分を、Ｓ７６において生成された照明光用マトリックスＭiを用いて、以下の式(6)より、
【００８８】
【数８】

ＬＭＳ値からＸＹＺ値に変換する（Ｓ８０）。
【００８９】
そして、合成部６０ｕが、プロジェクタ光変換部６０ｓによって変換されたＸＹＺ値と、照明光成分変換部６０ｔによって変換されたＸＹＺ値とを和演算することによって、使用環境下におけるプロジェクタのＲＧＢの三刺激値ＸＹＺが求められる（Ｓ８２）。すなわち、使用環境下におけるプロジェクタのＲＧＢの三刺激値ＸＹＺは、式(7)：
【００９０】
【数９】

によって求められる。また、プロジェクタの任意の出力色についても同様に、以下の式(8)を用いて求めることができる。
【００９１】
【数１０】

このようにして、本発明の一実施形態にかかる光センサ６０を用いて光検出を行えば、使用しているスクリーンがどのサンプルスクリーンと相関が強いかに応じて重み付けを行うことによって合成されたプロジェクタ用マトリックスＭdと照明光用マトリックスＭiとを用いてＬＭＳからＸＹＺへの変換を行っているので、プロジェクタの出力と照明光とが重なった色に対してもより高精度な測定が可能となる。
【図面の簡単な説明】
【図１】本実施形態の一例にかかるプロジェクタ２０を用いたシステムの概略説明図である。
【図２】本発明の一実施形態にかかる光センサ６０を備えるプロジェクタ２０内の画像処理部の機能ブロック図である。
【図３】本発明の一実施形態にかかる光センサ６０の機能ブロック図である。
【図４】本発明の一実施形態にかかる標準センサによるプロジェクタ光の測定処理を説明するためのフローチャートである。
【図５】プロジェクタ用マトリックスＭdnの生成処理について説明するためのフローチャートである。
【図６】本発明の一実施形態にかかる標準センサによる照明光の測定処理を説明するためのフローチャートである。
【図７】照明用マトリックスＭinの生成処理について説明するためのフローチャートである。
【図８】プロジェクタ毎の付属センサ６０ｈによるプロジェクタ光の測定処理を説明するためのフローチャートである。
【図９】使用環境下における光センサ６０による光測定処理を説明するためのフローチャートである。
【図１０】本発明の一実施形態にかかる使用環境下における光測定処理を行う光センサ６０の機能ブロック図である。
【図１１】重み付け係数Ｗnを求める第１例の場合のＰnとＱnとの関係を示す図である。
【図１２】重み付け係数Ｗnを求める第２例の場合のＰnとＱnとの関係を示す図である。
【符号の説明】
１０ スクリーン
２０ プロジェクタ
５０ 照明器具
６０ 光センサ
６０ａ ＬＭＳ／ＸＹＺ記録部
６０ｂ Pn計算部
６０ｃ Pn保存部
６０ｄ Ｍdn計算部
６０ｅ Ｍdn保存部
６０ｆ Ｍin計算部
６０ｇ Ｍin保存部
６０ｈ 付属センサ
６０ｉ Ｍo計算部
６０ｊ Ｍo保存部
６０ｋ キャリブレーション部
６０ｍ 光分離手段
６０ｎ 相関係数Ｐ(n)計算部
６０ｐ Ｗn計算部
６０ｑ Ｍd合成部
６０ｒ Ｍi合成部
６０ｓ プロジェクタ光成分変換部
６０ｔ 照明光成分変換部
６０ｕ 合成部
７０ 輝度計
８０ 外部照明
１００ 画像処理部
１１０ Ａ／Ｄ変換部
１２０ 色補正部
１３０ Ｄ／Ａ変換部
１４０ Ｌ／Ｖ駆動部
１５０ 色補正テーブル生成部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to light detection, more specifically, a light detection device, a projector, a light detection method, a program, and a recording medium that can perform measurement with higher accuracy.
[0002]
[Prior art]
When an image display device such as a projector is used, it is important that an image intended by the manufacturer can be reproduced even if the usage environment changes. As an idea for adjusting the appearance of such an image, there is an idea of color management for reproducing colors by managing input / output characteristics of a device.
[0003]
For example, a projector with a correction circuit described in Patent Document 1 includes a correction circuit suitable for appropriate white balance adjustment and luminance adjustment, and color information and luminance information of a projection surface on which an image is projected from the projector. Based on the above, white balance adjustment and luminance adjustment on the projection surface are performed, respectively, so that good white balance adjustment is possible and luminance unevenness can be avoided. Thus, in order to perform appropriate color reproduction, it is necessary to consider changes in the usage environment (for example, changes in the brightness and color of external illumination, changes in the color of the projection surface, etc.) detected using an optical sensor. There is.
[0004]
When a projector is provided with an optical sensor and information on the usage environment is acquired using the optical sensor, an expensive optical sensor cannot be used in order to prevent an increase in the cost of the projector as a whole. As such an optical sensor, for example, a three-channel optical sensor in which an RGB filter is superimposed on a photodiode is used. In this case, it is necessary to convert the RGB output of the optical sensor into tristimulus values XYZ. Conventionally, the RGB output of a projector is measured using the optical sensor and a high-precision luminance meter, a 3 × 3 matrix for conversion is obtained from the correspondence relationship, and conversion from RGB to XYZ is performed using the matrix. It is common to do.
[0005]
[Patent Document 1]
Japanese Patent No. 2973477
[Problems to be solved by the invention]
However, according to the above method, the output of the projector can be accurately converted from RGB to XYZ, but the illumination spectral distribution is different from that of the projector. For this reason, it is difficult to accurately convert RGB to XYZ even if the same matrix as the matrix is used for illumination. Further, when the color of the projection surface changes, the output of the projector and the spectral distribution of illumination change. For this reason, unless the matrix is changed to an appropriate one according to the color of the projection surface, it is difficult to perform conversion from RGB to XYZ with high accuracy.
[0006]
SUMMARY An advantage of some aspects of the invention is to provide a photodetection device, a projector, a photodetection method, a program, and a recording medium that can perform measurement with higher accuracy.
[0007]
[Means for Solving the Problems]
In view of the above problems, the invention described in claim 1 is a light detection device that measures luminance characteristics of a specific color output from a display device to a specific projection surface under a specific illumination light. The output of the light detection device for the color component of the specific color using the display device operator generated by combining the display device operators for the sample projection surface and the plurality of sample illumination lights, Display device conversion means for converting into a coordinate system value independent of the display device is provided.
[0008]
The invention according to claim 2 is the light detection device according to claim 1, wherein the light detection device is generated by combining the illumination operators for the plurality of sample projection surfaces and the plurality of sample illumination lights. The apparatus further includes illumination conversion means for converting the output of the light detection device for the color component of the illumination light into a coordinate system value independent of the display device using an operator.
[0009]
The invention according to claim 3 is the light detection device according to claim 1 or 2, wherein the sample is based on the measurement results for the plurality of sample projection planes and the measurement results for the projection plane being used. Correlation coefficient calculating means for obtaining a correlation coefficient indicating the degree of correlation between the projection plane and the projection plane being used is further provided, and based on the correlation coefficient, the projection plane being used and a plurality of sample projection planes The operator is synthesized by weighting according to the degree of correlation.
[0010]
According to a fourth aspect of the present invention, there is provided the photodetector according to the third aspect, wherein the correlation coefficient is a function having an inner product of characteristic vectors as a variable. A value measured by the long wavelength channel of the detection unit, a value of G of the display device measured by the medium wavelength channel of the light detection unit, and a value of B of the display device measured by the short wavelength channel of the light detection unit , As a component.
[0011]
The invention according to claim 5 is the light detection device according to any one of claims 1 to 4, wherein the specific illumination is converted before the conversion by the display conversion means or the illumination conversion means. It further comprises a light separating means for separating the light color component and the color component of the specific color.
[0012]
The invention according to claim 6 is the light detection device according to claim 5, wherein the light separation means outputs a luminance characteristic when the display device outputs black in a specific color output by the display device. The color component of the illumination light is separated from the color component of the specific color by subtracting from the luminance characteristic.
[0013]
The invention according to claim 7 is the photodetection device according to any one of claims 2 to 6, wherein the value of the coordinate system independent of the display device converted by the display device conversion means, It is configured to perform a sum operation on the coordinate system values independent of the display device converted by the illumination conversion means.
[0014]
The invention according to an eighth aspect is the light detection device according to any one of the first to seventh aspects, wherein the value of the coordinate system independent of the display device is XYZ.
[0015]
A ninth aspect of the present invention is a projector including the light detection device according to any one of the first to eighth aspects.
[0016]
The invention according to claim 10 is a light detection method for measuring a luminance characteristic of a specific color output from a display device to a specific projection plane under a specific illumination light, and includes a plurality of sample projection planes and Coordinates that do not depend on the display device for the output of the light detection device for the color component of the specific color using the display device operator generated by combining the display device operators for a plurality of illumination lights A display device conversion step for converting to a system value is provided.
[0017]
The invention according to claim 11 is a program for causing a computer to execute a light detection process for measuring a luminance characteristic of a specific color output from a display device to a specific projection plane under a specific illumination light. The output of the light detection device for the color component of the specific color using the display device operator generated by combining the display device operators for the plurality of sample projection planes and the plurality of illumination lights Is a program for causing a computer to execute display device conversion processing for converting the value into a coordinate system value independent of the display device.
[0018]
The invention according to claim 12 records a program for causing a computer to execute a light detection process for measuring a luminance characteristic of a specific color output from a display device to a specific projection surface under a specific illumination light. A computer-readable recording medium using the display device operator generated by combining the display device operators for a plurality of sample projection planes and a plurality of illumination lights. A computer-readable recording medium storing a program for causing a computer to execute a conversion process for a display device for converting an output of the light detection device for a color component of the display device into a coordinate system value independent of the display device is there.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0020]
System configuration
FIG. 1 is a schematic explanatory diagram of a system using a projector 20 including a photosensor 60 as a photodetection device according to the present invention.
[0021]
A predetermined image is projected from a projector 20 provided almost in front of the screen 10 (projection surface). In this case, the appearance of the image projected on the screen 10 by the external illumination 80 from the luminaire 50 is greatly different. For example, even when the same white is displayed, it looks bright white or dark white depending on the intensity of the external illumination 80. Further, the appearance of the image differs depending on the color of the screen regardless of the intensity of the external illumination 80 (even if it is 0).
[0022]
FIG. 2 is a functional block diagram of the image processing unit 100 in the projector 20 including the optical sensor 60 according to the embodiment of the present invention.
[0023]
The image processing unit 100 in the projector 20 shown in FIG. 2 applies an A / D conversion unit 110 that converts an analog image input signal to a digital signal, and applies a color correction table to each RGB image input signal. A color correction unit 120 for performing color correction of the image, a D / A conversion unit 130 for converting a digital signal into an analog signal, and an L / V (light valve) for projecting and displaying an image by driving a liquid crystal light valve. ) A drive unit 140, a device characteristic storage memory 160 for storing device (projector) characteristics, and a color correction table generation unit 150. When the optical sensor 60 according to the present invention measures the brightness of the reflected light from the projector and the screen of the external illumination, the color correction table generation unit 150 determines the device characteristics stored in the device characteristic storage memory 160 and the optical sensor 60. A color correction table in consideration of the influence of external illumination is generated based on the colorimetric values.
[0024]
Configuration of optical sensor 60
Next, with reference to FIG. 3, the measurement process in the optical sensor 60 concerning one Embodiment of this invention is demonstrated.
[0025]
The optical sensor 60 shown in FIG. 3 records the correspondence between the value LMS measured by the standard sensor 75 and the value XYZ (value of the coordinate system independent of the display device) measured by the luminance meter 70 for the same measurement target light. LMS / XYZ recording unit 60a, Pn calculation unit 60b for calculating sample screen characteristic vector Pn, Pn storage unit 60c for storing calculated sample screen characteristic vector Pn, and projector matrix Mdn are calculated. Mdn calculating unit 60d for storing, an Mdn storing unit 60e for storing the projector matrix Mdn, a Min calculating unit 60f for calculating the lighting matrix Min, and a Min storing unit for storing the lighting matrix Min 60g and the light to be measured is received by an optical sensor with three types of filters superimposed, and three types corresponding to each. Value (hereinafter referred to as “LMS value”) attached sensor 60h provided for each machine, correspondence between LMS and XYZ recorded in LMS / XYZ recording unit 60a, and measured value of attached sensor 60h And a Mo calculation unit 60i for calculating the calibration matrix Mo and a Mo storage unit 60j for storing the calibration matrix Mo.
[0026]
The standard sensor 75 is a reference sensor determined for one model, and the measurement target light is received by an optical sensor in which three types of filters are superimposed, and three types of values ( (Hereinafter referred to as “LMS value”).
[0027]
In this embodiment, the projector itself includes an LMS / XYZ recording unit 60a, a Pn calculation unit 60b, a Pn storage unit 60c, an Mdn calculation unit 60d, an Mdn storage unit 60e, a Min calculation unit 60f, a Min storage unit 60g, and an attached sensor. Although 60h, Mo calculation part 60i, and Mo preservation | save part 60j are provided, it is not necessary to provide these in a projector main body, and it can also comprise with a computer system separate from a projector main body.
[0028]
Measurement processing of projector light by standard sensor
Next, with reference to FIG. 4, the projector light measurement process by the standard sensor according to the embodiment of the present invention will be described.
[0029]
As shown in FIG. 4, first, under a dark room, four types of R (red), G (green), B (blue), and K (black) colors of a display device (projector) are irradiated on several types of sample screens (S10). The LMS value is measured by the standard sensor 75, and the XYZ value is measured by the luminance meter 70 capable of measuring tristimulus values (S12). Here, the color of the sample screen is preferably selected as evenly as possible within the range of the screen color desired to be measurable by the optical sensor 60. Also, the greater the number of sample screens, the higher the conversion accuracy. On the other hand, the amount of calculation increases, so about 6 to 9 types are appropriate.
[0030]
The measurement in S12 provides a data pair of the correct XYZ value measured by the luminance meter 70 and the output voltage (LMS) from the standard sensor 75 for each screen and each output light. It is recorded in the LMS / XYZ pair recording unit 60a (S14). An example of data recorded in the LMS / XYZ pair recording unit 60a is as follows.
[0031]
When the color to be measured is red (R, G, B) = (255, 0, 0), the measured value with the standard sensor is (L_Rn, M_Rn, S_Rn) And the measured value on the luminance meter is (X_Rn, Y_Rn, Z_Rn).
[0032]
When the color to be measured is green (R, G, B) = (0, 255, 0), the measured value with the standard sensor is (L_Gn, M_Gn, S_Gn) And the measured value on the luminance meter is (X_Gn, Y_Gn, Z_Gn).
[0033]
When the color to be measured is blue (R, G, B) = (0, 0, 255), the measured value with the standard sensor is (L_Bn, M_Bn, S_Bn) And the measured value on the luminance meter is (X_Bn, Y_Bn, Z_Bn).
[0034]
When the color to be measured is black (R, G, B) = (0, 0, 0), the measured value with the standard sensor is (L_Kn, M_Kn, S_Kn) And the measured value on the luminance meter is (X_Kn, Y_Kn, Z_Kn).
[0035]
Here, n is 0, 1, 2,..., N and represents the type of screen.
[0036]
Then, the Pn calculation unit 60b is based on the data recorded in the LMS / XYZ pair recording unit 60a and has the following formula:
[0037]
[Expression 1]

Is calculated and stored in the Pn storage unit 60c (S16).
[0038]
Generation process of projector matrix Mdn
Next, generation processing of the projector matrix Mdn will be described with reference to FIG.
[0039]
First, the Mdn calculation unit 60d, based on data recorded in the LMS / XYZ pair recording unit 60a, a projector matrix Mdn for each screen:
[0040]
[Expression 2]

(S20) and stored in the Pn storage unit 60c (S24).
[0041]
Measurement process of illumination light by standard sensor
Next, with reference to FIG. 6, the measurement process of the illumination light by the standard sensor concerning one Embodiment of this invention is demonstrated.
[0042]
As shown in FIG. 6, various types of sample screens are irradiated with various illumination lights (S30), LMS values are measured by the standard sensor 75, and XYZ values are measured by a luminance meter 70 capable of measuring tristimulus values. (S32). As the illumination light, an incandescent lamp, a white fluorescent lamp (with a color temperature of about 4000K), a daylight white fluorescent lamp (with a color temperature of about 5000K), or the like that is often used in the usage environment is selected.
[0043]
As in the projector light measurement process, the color of the sample screen is preferably selected as uniformly as possible within the range of the screen color desired to be measurable by the optical sensor 60. Also, the greater the number of sample screens, the higher the conversion accuracy. On the other hand, the calculation amount increases, so about 6 to 9 types are appropriate.
[0044]
The measurement in S32 provides a data pair of the correct XYZ value measured by the luminance meter 70 and the output voltage (LMS) from the standard sensor 75 for each screen and each illumination light. It is recorded in the LMS / XYZ pair recording unit 60a (S34). An example of data recorded in the LMS / XYZ pair recording unit 60a is as follows.
[0045]
The measured value with the standard sensor when the illumination to be measured is illumination α (L_{α n}, M_{α n}, S_{α n}) And the measured value on the luminance meter is (X_{α n}, Y_{α n}, Z_{α n}).
[0046]
The measured value with the standard sensor when the illumination to be measured is illumination β (L_{β n}, M_{β n}, S_{β n}) And the measured value on the luminance meter is (X_{β n}, Y_{β n}, Z_{β n}).
[0047]
The measured value with the standard sensor when the illumination to be measured is illumination γ (L_{γ n}, M_{γ n}, S_{γ n}) And the measured value on the luminance meter is (X_{γ n}, Y_{γ n}, Z_{γ n}).
[0048]
Here, n is 0, 1, 2,..., N and represents the type of screen.
[0049]
Generation process of lighting matrix Min
Next, the generation process of the illumination matrix Min will be described with reference to FIG.
[0050]
First, the Min calculation unit 60f, based on the data recorded in the LMS / XYZ pair recording unit 60a, the illumination matrix Min for each screen:
[0051]
[Equation 3]

(S40) and stored in the Min storage unit 60f (S42).
[0052]
Measuring process of projector light by attached sensor 60h for each projector
Next, projector light measurement processing by the attached sensor 60h for each projector will be described with reference to FIG. This process is performed to generate a calibration matrix for each aircraft in order to correct individual differences of attached sensors.
[0053]
As shown in FIG. 8, first, for each airframe, under the dark room, the reference screen is irradiated with the three colors R (red), G (green), and B (blue) of the display device (projector) (S50). The LMS value is measured by 60h (S52). An example of the measurement data in S52 is as follows.
[0054]
When the color to be measured is red (R, G, B) = (255, 0, 0), the measured value with the attached sensor is (L_R0', M_R0', S_R0').
[0055]
When the color to be measured is green (R, G, B) = (0, 255, 0), the measured value with the attached sensor is (L_G0', M_{G 0}', S_G0').
[0056]
When the color to be measured is blue (R, G, B) = (0, 0, 255), the measured value with the attached sensor is (L_B0', M_B0', S_B0').
[0057]
And Mo calculation part 60i uses the following formula | equation (3),
[0058]
[Expression 4]

Based on the measurement value of the standard sensor and the measurement value of the attached sensor of each aircraft, a calibration matrix Mo is obtained (S54) and stored in the Mo storage unit 60j (S56).
[0059]
Light measurement processing under usage environment
FIG. 10 is a functional block diagram of the optical sensor 60 that performs the light measurement process under the usage environment.
[0060]
The optical sensor 60 shown in FIG. 10 includes an attached sensor 60h that measures the LMS value of the measurement target light, a calibration unit 60K that performs calibration using the calibration matrix Mo stored in the Mo storage unit 60j, The light separation means 60m for separating the sensor output after calibration into the projector light component and the illumination light component, the correlation coefficient P (n) between the screen characteristic vector P in the use environment and the sample screen characteristic vector Pn Correlation coefficient P (n) calculation unit 60n to be obtained, Wn calculation unit 60p for obtaining a weighting coefficient Wn for synthesizing a matrix in a use environment from the correlation coefficient P (n), a projector matrix Mdn, and a weighting coefficient An Md synthesis unit 60q for synthesizing a projector matrix Md in a use environment from Wn, and an illumination light matrix Mi synthesizer 60r for synthesizing illumination light matrix Mi under the usage environment from the projector Min and weighting coefficient Wn, and projector light component converter for converting projector light components from LMS values to XYZ values using projector matrix Md 60s, an illumination light component conversion unit 60t that converts the illumination light component from an LMS value to an XYZ value using the illumination light matrix Mi, an XYZ value converted by the projector light conversion unit 60s, and an illumination light component conversion unit 60t And a synthesizer 60u that obtains RGB tristimulus values XYZ of the projector in the operating environment by performing a sum operation on the XYZ values converted by the above.
[0061]
Next, with reference to FIG. 9, the light measurement process by the optical sensor 60 under the use environment will be described.
[0062]
The light measurement process in the optical sensor 60 described here is performed by executing a program recorded in a program storage unit (not shown) of the optical sensor 60. The program storage unit constitutes a medium on which a program is recorded. Further, the processing program itself is included within the scope of the present invention.
[0063]
As shown in FIG. 9, in a use environment (with illumination, any screen), four colors of R (red), G (green), B (blue), and K (black) of the display device (projector) are irradiated (S60). ), The LMS value is measured by the attached sensor 60h (S62). An example of the measurement data in S62 is as follows.
[0064]
When the color to be measured is red (R, G, B) = (255, 0, 0), the measured value with the attached sensor is (L_R', M_R', S_R').
[0065]
When the color to be measured is green (R, G, B) = (0, 255, 0), the measured value with the attached sensor is (L_G', M_G', S_G').
[0066]
When the color to be measured is blue (R, G, B) = (0, 0, 255), the measured value with the attached sensor is (L_B', M_B', S_B').
[0067]
When the color to be measured is black (R, G, B) = (0, 0, 0), the measured value with the attached sensor is (L_K', M_K', S_K').
[0068]
Then, the calibration unit 60K uses the calibration matrix Mo stored in the Mo storage unit 60j, as shown in the following equation (4).
[0069]
[Equation 5]

Calibration is performed (S64).
[0070]
L_G', M_G', S_G', L_B', M_B', S_B'And L_K', M_K', S_KPerform the same calibration for '.
[0071]
Then, the light separating unit 60m separates the sensor output after calibration obtained in S64 into a projector light component and an illumination light component (S66).
[0072]
Specifically, in S66, the sensor output value L when K (black) is output by the display device._KM_KS_KIs considered to be the sum of the black output of the display device and the illumination light, so the projector light component is
L_R-L_K, M_R-M_K, S_R-S_K
L_G-L_K, M_G-M_K, S_G-S_K
L_B-L_K, M_B-M_K, S_B-S_K
The illumination light component is
L_K, M_K, S_K
It becomes.
[0073]
In this way, the projector light component and the illumination light component are separated.
[0074]
On the other hand, the correlation coefficient P (n) calculation unit 60n calculates the correlation coefficient P (n) between the screen characteristic vector P in the use environment and the sample screen characteristic vector Pn in order to examine the screen characteristic in the use environment. Obtain (S68 and S70). Here, the screen characteristic vector P under the usage environment is
[0075]
[Formula 6]

And the correlation coefficient P (n) is

It is defined as Here, n is an integer of 0 to N and represents the type of screen.
[0076]
Thus, the screen characteristic vector P is a value obtained by measuring R of the display device using the long wavelength channel of the light detection unit, a value of G of the display device measured by the medium wavelength channel of the light detection unit, and a display. This is a vector whose component is a value obtained by measuring B of the apparatus with the short wavelength channel of the light detection unit, and the correlation coefficient P (n) is a function having the inner product of two characteristic vectors as a variable.
[0077]
If the screen to be used is the same as the sample screen, P (n) = 1. If the screen to be used has no correlation with the sample screen, P (n) = 0.
[0078]
That is, a correlation coefficient indicating the degree of correlation between the sample screen and the screen being used is obtained based on the measurement results for the plurality of sample screens and the measurement results for the screen being used. Then, the projector matrix Mdn and the illumination matrix Min are synthesized by performing weighting according to which sample screen and the correlation degree of the screen being used are strong based on the correlation coefficient.
[0079]
Then, the Wn calculator 60p obtains a weighting coefficient Wn for synthesizing the matrix under the use environment from the correlation coefficient P (n) obtained in S70 (S72). The weighting factor Wn is
Wn = Qn / (Q₀+ Q₁+ Q₂+ ... + Q_N)
Defined by There are the following two examples of how to obtain the weighting coefficient Wn.
[0080]
First example
The first example is
Qn = 1 / (1001-1000Pn)
This is the case. FIG. 11 is a diagram showing the relationship between Pn and Qn in the case of the first example for obtaining the weighting coefficient Wn.
[0081]
Second example
The second example is

This is the case. FIG. 12 shows a relationship between Pn and Qn in the case of the second example for obtaining the weighting coefficient Wn. In this example, P ′ is about 0.98, but the value of P ′ varies depending on how the sample screen is selected.
[0082]
Since the conversion accuracy of the first example can be expected, it is preferable to use the first example if there is no problem in the size of variables. The calculation in the second example is simpler than that in the first example, but the threshold value P ′ needs to be determined. The optimum value of the threshold value P ′ varies depending on how the sample screen is selected, but a value around P ′ = 0.98 is appropriate. Both Wn and Qn in the following formula take values in the range of 0-1.
[0083]
Next, the Md combining unit 60q uses the following formula from the projector matrix Mdn stored in the Mdn storage unit 60e and the weighting coefficient Wn calculated by the Wn calculation unit 60p:

Thus, the projector matrix Md under the usage environment is synthesized (S74).
[0084]
Similarly, the Mi combining unit 60r uses the following formula from the illumination light matrix Min stored in the Min storing unit 60g and the weighting coefficient Wn calculated by the Wn calculating unit 60p:

Thus, the illumination light matrix Mi under the usage environment is synthesized (S76).
[0085]
Then, the projector light component conversion unit 60s uses the projector matrix Md generated in S74, the projector light component separated by the light separating means 60m, from the following equation (5):
[0086]
[Expression 7]

The LMS value is converted into an XYZ value (S78). (L_G−L_K, M_G−M_K, S_G−S_K) And (L_B−L_K, M_B−M_K, S_B−S_KThe same applies to).
[0087]
Further, the illumination light component conversion unit 60t uses the illumination light matrix Mi generated in S76 to convert the illumination light component separated by the light separation means 60m from the following equation (6):
[0088]
[Equation 8]

The LMS value is converted into an XYZ value (S80).
[0089]
Then, the combining unit 60u calculates the sum of the XYZ values converted by the projector light conversion unit 60s and the XYZ values converted by the illumination light component conversion unit 60t, so that the RGB tristimulus of the projector in the usage environment is obtained. A value XYZ is obtained (S82). That is, the RGB tristimulus values XYZ of the projector under the usage environment are expressed by the following equation (7):
[0090]
[Equation 9]

Sought by. Similarly, any output color of the projector can be obtained using the following equation (8).
[0091]
[Expression 10]

In this way, when light detection is performed using the optical sensor 60 according to the embodiment of the present invention, the light is synthesized by weighting according to which sample screen the screen being used has a strong correlation with. Since conversion from LMS to XYZ is performed using the projector matrix Md and the illumination light matrix Mi, more accurate measurement is possible even for colors in which the projector output and illumination light overlap. .
[Brief description of the drawings]
FIG. 1 is a schematic explanatory diagram of a system using a projector 20 according to an example of the present embodiment.
FIG. 2 is a functional block diagram of an image processing unit in the projector 20 including the optical sensor 60 according to the embodiment of the present invention.
FIG. 3 is a functional block diagram of an optical sensor 60 according to an embodiment of the present invention.
FIG. 4 is a flowchart for explaining projector light measurement processing by a standard sensor according to an embodiment of the present invention.
FIG. 5 is a flowchart for explaining generation processing of a projector matrix Mdn.
FIG. 6 is a flowchart for explaining illumination light measurement processing by a standard sensor according to an embodiment of the present invention.
FIG. 7 is a flowchart for explaining generation processing of an illumination matrix Min.
FIG. 8 is a flowchart for explaining projector light measurement processing by an attached sensor 60h for each projector.
FIG. 9 is a flowchart for explaining light measurement processing by the optical sensor 60 in a use environment.
FIG. 10 is a functional block diagram of an optical sensor 60 that performs light measurement processing under a use environment according to an embodiment of the present invention.
FIG. 11 is a diagram showing the relationship between Pn and Qn in the case of the first example for obtaining a weighting coefficient Wn.
FIG. 12 is a diagram showing a relationship between Pn and Qn in the case of a second example for obtaining a weighting coefficient Wn.
[Explanation of symbols]
10 screens
20 Projector
50 Lighting equipment
60 Optical sensor
60a LMS / XYZ recording part
60b Pn calculator
60c Pn storage
60d Mdn calculator
60e Mdn storage
60f Min calculation part
60g Min storage
60h Attached sensor
60i Mo calculator
60j Mo storage
60k calibration section
60m light separation means
60n correlation coefficient P (n) calculator
60p Wn calculator
60q Md synthesis unit
60r Mi synthesis unit
60s projector light component converter
60t illumination light component converter
60u synthesis unit
70 Luminance meter
80 External lighting
100 Image processing unit
110 A / D converter
120 color correction unit
130 D / A converter
140 L / V drive
150 color correction table generator

Claims (11)

A light detection device that measures a luminance characteristic of a specific color output from a display device to a specific projection surface under a specific illumination light,
Using the display device operator generated by summing each display device operator multiplied by a weighting coefficient, the output of the light detection device for the color component of the specific color is displayed on the display device. a display device for converting means for converting the value of the independent coordinate,
Based on the measurement results for the plurality of sample projection planes and the measurement results for the projection plane in use, a correlation coefficient indicating the degree of correlation between the plurality of sample projection planes and the projection plane in use is obtained. Correlation coefficient calculation means,
The display device operator is:
The measurement value of the coordinate system depending on the device when outputting K of the display device is subtracted from the measurement value of the coordinate system depending on the device when RGB of the display device is output to the sample projection plane. What
The measurement value of the coordinate system independent of the device when outputting K of the display device is subtracted from the measurement value of the coordinate system independent of the device when outputting RGB of the display device to the sample projection plane. matrix der which associates to what was is,
Based on the correlation coefficient, the weighting coefficient is determined.
Photodetector. The photodetection device according to claim 1,
Using the illumination operator generated by summing each of the illumination operators multiplied by a weighting factor, the output of the light detection device for the color component of the illumination light depends on the display device Further comprising an illumination conversion means for converting into a coordinate system value that is not
The lighting operator is:
It is a matrix in which the measurement value of the coordinate system depending on the device when the sample illumination light is irradiated to the sample projection surface is associated with the measurement value of the coordinate system independent of the device.
Photodetector. The photodetection device according to claim 1 or 2 ,
The correlation coefficient is a function having the inner product of characteristic vectors as a variable;
The characteristic vector is a value obtained by measuring R of the display device using the long wavelength channel of the light detection unit, a value of G of the display device measured by the medium wavelength channel of the light detection unit, and a light detection of B of the display device. Detection device, which is a vector whose components are the values measured by the short wavelength channel of the unit. The photodetection device according to any one of claims 1 to 3 ,
A light detection device further comprising: a light separation unit that separates the color component of the specific illumination light and the color component of the specific color before the conversion by the display device conversion unit or the illumination conversion unit. The light detection device according to claim 4 ,
The light separation means subtracts the luminance characteristic when black is output from the display device from the luminance characteristic of the specific color output by the display device, and the color component of the specific illumination light and the specific color Detection device that separates the color components of the light. The light detection device according to claim 2 ,
A photodetection device that performs a sum operation on a coordinate system value that does not depend on the display device converted by the display device conversion unit and a coordinate system value that does not depend on the display device converted by the illumination conversion unit . The photodetection device according to any one of claims 1 to 6 ,
The photodetection device, wherein the value of the coordinate system independent of the display device is XYZ. Projector including a light detecting device according to any one of claims 1 to 7. A light detection method for measuring a luminance characteristic of a specific color output from a display device to a specific projection surface under a specific illumination light,
Using the display device operator generated by summing each display device operator multiplied by a weighting coefficient, the output of the light detection device for the color component of the specific color is displayed on the display device. a display device for a conversion step for converting the value of the independent coordinate,
Based on the measurement results for the plurality of sample projection planes and the measurement results for the projection plane in use, a correlation coefficient indicating the degree of correlation between the plurality of sample projection planes and the projection plane in use is obtained. A correlation coefficient calculation step,
The display device operator is:
The measurement value of the coordinate system depending on the device when outputting K of the display device is subtracted from the measurement value of the coordinate system depending on the device when RGB of the display device is output to the sample projection plane. What
The measurement value of the coordinate system independent of the device when outputting K of the display device is subtracted from the measurement value of the coordinate system independent of the device when outputting RGB of the display device to the sample projection plane. matrix der which associates to what was is,
Based on the correlation coefficient, the weighting coefficient is determined.
Light detection method. A program for causing a computer to execute a light detection process for measuring a luminance characteristic of a specific color output from a display device to a specific projection plane under a specific illumination light,
Using the display device operator generated by summing each display device operator multiplied by a weighting coefficient, the output of the light detection device for the color component of the specific color is displayed on the display device. display a device for conversion processing to convert the value of the independent coordinate,
Based on the measurement results for the plurality of sample projection planes and the measurement results for the projection plane in use, a correlation coefficient indicating the degree of correlation between the plurality of sample projection planes and the projection plane in use is obtained. A program for causing a computer to execute correlation coefficient calculation processing ,
The display device operator is:
The measurement value of the coordinate system depending on the device when outputting K of the display device is subtracted from the measurement value of the coordinate system depending on the device when RGB of the display device is output to the sample projection plane. What
The measurement value of the coordinate system independent of the device when outputting K of the display device is subtracted from the measurement value of the coordinate system independent of the device when outputting RGB of the display device to the sample projection plane. matrix der which associates to what was is,
Based on the correlation coefficient, the weighting coefficient is determined.
program. A computer-readable recording medium storing a program for causing a computer to execute a light detection process for measuring a luminance characteristic of a specific color output from a display device to a specific projection surface under a specific illumination light There,
Using the display device operator generated by summing each display device operator multiplied by a weighting coefficient, the output of the light detection device for the color component of the specific color is displayed on the display device. display a device for conversion processing to convert the value of the independent coordinate,
Based on the measurement results for the plurality of sample projection planes and the measurement results for the projection plane in use, a correlation coefficient indicating the degree of correlation between the plurality of sample projection planes and the projection plane in use is obtained. A computer-readable recording medium that records a program for causing a computer to execute correlation coefficient calculation processing ,
The display device operator is:
The measurement value of the coordinate system depending on the device when outputting K of the display device is subtracted from the measurement value of the coordinate system depending on the device when RGB of the display device is output to the sample projection plane. What
The measurement value of the coordinate system independent of the device when outputting K of the display device is subtracted from the measurement value of the coordinate system independent of the device when outputting RGB of the display device to the sample projection plane. matrix der which associates to what was is,
Based on the correlation coefficient, the weighting coefficient is determined.
recoding media.

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