JP2004241882A

JP2004241882A - Video signal correction circuit

Info

Publication number: JP2004241882A
Application number: JP2003026737A
Authority: JP
Inventors: Toshiyuki Kato; 敏行加藤; Masahiro Takeshima; 正弘竹島
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-02-04
Filing date: 2003-02-04
Publication date: 2004-08-26
Anticipated expiration: 2023-02-04
Also published as: JP4155043B2

Abstract

<P>PROBLEM TO BE SOLVED: To view a video in an optimum skin color reproduction state. <P>SOLUTION: A video signal correction circuit is provided with a skin color luminance distribution detecting circuit which detects a luminance distribution of skin-color parts in one frame, luminance distribution detecting circuit which detects a luminance distribution in one frame from a luminance signal of a video signal, a histogram conversion type gradation correcting circuit which multiplies luminance signal by gradations of a luminance signal corresponding to the luminance distribution of skin-color parts of the video signal and a histogram conversion type gradation correcting circuit control signal corresponding to the luminance distribution, a color saturation degree correcting circuit controller which generates a color saturation degree correcting circuit control signal corresponding to the histogram conversion type gradation correcting circuit control signal, and a color saturation degree correcting circuit which inputs the output of the color saturation degree correcting circuit controller and the luminance signal and multiplies color saturation degree corrections corresponding to the color saturation degree correcting circuit control signal by a color difference signal. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明はヒストグラム変換型階調補正回路および色飽和度補正回路の制御に関し、特に映像信号の肌色部分の輝度分布に応じてヒストグラム変換型階調補正回路および色飽和度補正回路を制御する回路および映像信号補正回路に関する。
【０００２】
【従来の技術】
近年、テレビジョンの大画面化は目ざましいものがあり、そのため画質に関する要求はますます高まりつつある。とりわけ人間の目は人の肌の再現に関しては敏感であり、人の肌の階調が画質に与える影響は大なるものがある。
【０００３】
図７は従来の肌色輝度向上回路のブロック構成図を示す（例えば特許文献１）。映像信号補正回路制御装置は映像信号の色差信号から１フレーム中の肌色部分の面積を検出する肌色面積検出回路７０１と、映像信号の色差信号と輝度信号から１フレーム中の肌色部分の平均輝度レベルを検出する肌色平均輝度レベル検出回路７０２と、映像信号の輝度信号から１フレームの平均輝度レベルを検出する平均輝度レベル検出回路７０３と、前記肌色面積検出回路からの出力と前記肌色平均輝度レベル検出回路からの出力と前記平均輝度レベル検出回路からの出力を入力として１フレームの肌色部分の面積と１フレームの肌色部分の平均輝度レベルと１フレームの平均輝度レベルに応じたガンマ補正回路制御信号を作成するガンマ補正回路制御装置７０４と、前記ガンマ補正回路制御装置からの出力を入力としてガンマ補正回路制御信号に応じたガンマ補正を映像信号の輝度信号に掛けるガンマ補正回路７０５を備えた構成である。
【０００４】
以上のように構成された従来の肌色輝度向上回路においては、テレビジョンセットのＣＲＴのビーム量を調整するＡＣＬや映像信号の黒レベルを調整する黒伸長補正の副作用によって暗くくすんでしまった肌色の輝度レベルを、映像信号の平均輝度レベルと肌色部分の平均輝度レベルに応じて向上させる。
【０００５】
【特許文献１】
特開平７−２８８８３９号公報
【０００６】
【発明が解決しようとする課題】
しかしながら前記のような構成では、映像信号の平均輝度レベルと肌色部分の平均輝度レベルで補正を行うだけであり、肌色部分の輝度分布が高輝度側と低輝度側の両側に大きく分かれている場合と中輝度に集中している場合にはともに肌色部分の平均輝度が中輝度域となることから双方の区別が付かず、また肌色部分の輝度レベルを向上すると同時に肌色部分の階調性を損なうという不具合があるなど、肌色の輝度分布に応じた適切な映像信号補正を掛けることができなかった。
【０００７】
本発明はかかる点に鑑み、視聴者が映像の状態に応じた最適な映像信号補正状態でのテレビジョンの視聴を可能とする映像信号補正回路を提供することを目的とする。
【０００８】
【課題を解決するための手段】
映像信号の色差信号と輝度信号から１フレーム中の肌色部分の輝度分布を検出する肌色輝度分布検出回路と、映像信号の輝度信号から１フレーム中の輝度分布を検出する輝度分布検出回路と、前記肌色輝度分布検出回路からの出力と前記輝度分布検出回路からの出力を入力として１フレーム中の映像信号の肌色部分の輝度分布と１フレーム中の輝度分布に応じたヒストグラム変換型階調補正回路制御信号を作成するヒストグラム変換型階調補正回路制御装置と、前記ヒストグラム変換型階調補正回路制御装置からの出力を入力としてヒストグラム変換型階調補正回路制御信号に応じた階調補正を輝度信号に掛けるヒストグラム変換型階調補正回路と、前記ヒストグラム変換型階調補正回路制御装置からの出力を入力としてヒストグラム変換型階調補正回路制御信号に応じた色飽和度補正回路制御信号を作成する色飽和度補正回路制御装置と、前記色飽和度補正回路制御装置からの出力と輝度信号を入力として色飽和度補正回路制御信号に応じた色飽和度補正を色差信号に掛ける色飽和度補正回路を備えた構成としている。
【０００９】
本発明は前記した構成により、映像信号の色差信号と輝度信号から１フレーム中の肌色部分の輝度分布を検出する肌色輝度分布検出回路の出力と映像信号の輝度信号から１フレーム中の輝度分布を検出する輝度分布検出回路の出力の前者または両者からヒストグラム変換型階調補正回路制御装置において映像状態を算出し、ヒストグラム変換型階調補正回路制御装置においてこの映像状態に応じたヒストグラム変換型階調補正回路制御信号を作成し、ヒストグラム変換型階調補正回路制御装置からの出力信号により映像信号の状態に応じた最適なヒストグラム変換型階調補正を行い、また場合によって色飽和度補正回路制御装置においてヒストグラム変換型階調補正回路制御装置からの出力信号に応じた色飽和度補正回路制御信号を作成し、色飽和度補正回路制御装置からの出力信号によりヒストグラム変換型階調補正回路制御装置からの出力信号に応じた最適な色飽和度補正を行う。
【００１０】
【発明の実施の形態】
（実施の形態１）
図１は本発明の一実施例における映像信号補正回路を示す。図１において、１０１は映像信号から１フレーム中の肌色部分の輝度分布を検出する肌色輝度分布検出回路であり、１０２は前記肌色輝度分布検出回路からの出力を入力として１フレームの肌色輝度分布に応じたヒストグラム変換型階調補正回路制御信号を作成するヒストグラム変換型階調補正回路制御装置であり、１０３は前記ヒストグラム変換型階調補正回路制御装置からの出力を入力としてヒストグラム変換型階調補正回路制御信号に応じた階調補正を輝度信号に掛けるヒストグラム変換型階調補正回路である。
【００１１】
以上のように構成された映像信号補正回路について以下その動作説明を行う。まず、図１における肌色輝度分布検出回路１０１において映像信号から１フレーム中の肌色部分の輝度分布を検出し、検出した結果を電圧に変換する。なお、検出回路の出力は電圧だけでなく電流でも良いことはいうまでもない。検出された肌色部分の輝度分布を図１におけるヒストグラム変換型階調補正回路制御装置１０２に入力し１フレームの肌色輝度分布に応じたヒストグラム変換型階調補正回路制御信号を作成し電圧または電流に変換して出力する。出力されたヒストグラム変換型階調補正回路制御信号はヒストグラム変換型階調補正回路１０３に入力され、ヒストグラム変換型階調補正回路制御信号に応じたヒストグラム変換型階調補正を映像信号の輝度信号に掛ける。
【００１２】
以上のように本実施の形態１によれば１フレームの肌色部分の輝度分布を検出することで映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正が可能となる。
【００１３】
（実施の形態２）
図２は本発明の一実施例における映像信号補正回路のブロック構成図を示す。図２において、上記実施の形態１と構成が異なる点は、肌色輝度分布検出回路１０１に加えて輝度分布検出回路２０６を備え、肌色輝度分布検出回路１０１の出力に加えて輝度分布検出回路２０６の出力をヒストグラム変換型階調補正回路制御装置２０２の入力とした構成としていることである。輝度分布検出回路２０６は輝度信号から１フレーム中の輝度分布を検出する。他の構成については実施の形態１と同様なので説明を省略する。
【００１４】
以上のように構成された映像信号補正回路について以下その動作説明を行う。まず、図２における肌色輝度分布検出回路１０１において映像信号から１フレーム中の肌色部分の輝度分布を検出し、検出した結果を電圧に変換する。なお、検出回路の出力は電圧だけでなく電流でも良いことはいうまでもない。また図２における輝度分布検出回路２０６において映像信号から１フレーム中の輝度分布を検出し、検出した結果を電圧または電流に変換する。検出された肌色部分の輝度分布と輝度分布を図２におけるヒストグラム変換型階調補正回路制御装置２０２に入力し１フレーム中の映像信号の肌色部分の輝度分布と１フレーム中の輝度分布に応じたヒストグラム変換型階調補正回路制御信号を作成し電圧または電流に変換して出力する。出力されたヒストグラム変換型階調補正回路制御信号はヒストグラム変換型階調補正回路１０３に入力され、ヒストグラム変換型階調補正回路制御信号に応じたヒストグラム変換型階調補正を映像信号の輝度信号に掛ける。
【００１５】
以上のように本実施の形態２によれば１フレーム中の映像信号の肌色部分の輝度分布と１フレーム中の輝度分布を検出することで映像の肌色部分の輝度分布と輝度分布に応じた最適なヒストグラム変換型階調補正が可能となる。
【００１６】
（実施の形態３）
図３は本発明の一実施例における映像信号補正回路のブロック構成図を示す。図３において、１０１は映像信号から１フレーム中の肌色部分の輝度分布を検出する肌色輝度分布検出回路であり、１０２は前記肌色輝度分布検出回路からの出力を入力として１フレームの肌色輝度分布に応じたヒストグラム変換型階調補正回路制御信号を作成するヒストグラム変換型階調補正回路制御装置であり、１０３は前記ヒストグラム変換型階調補正回路制御装置からの出力を入力としてヒストグラム変換型階調補正回路制御信号に応じた階調補正を輝度信号に掛けるヒストグラム変換型階調補正回路であり、３０４は前記ヒストグラム変換型階調補正回路制御装置からの出力を入力としてヒストグラム変換型階調補正回路制御信号に応じた色飽和度補正回路制御信号を作成する色飽和度補正回路制御装置であり、３０５は前記色飽和度補正回路制御装置からの出力と輝度信号を入力として色飽和度補正回路制御信号に応じた色飽和度補正を色差信号に掛ける色飽和度補正回路である。
【００１７】
以上のように構成された映像信号補正回路について以下その動作説明を行う。まず、図３における肌色輝度分布検出回路１０１において映像信号から１フレーム中の肌色部分の輝度分布を検出し、検出した結果を電圧に変換する。なお、検出回路の出力は電圧だけでなく電流でも良いことはいうまでもない。検出された肌色部分の輝度分布を図３におけるヒストグラム変換型階調補正回路制御装置１０２に入力し１フレームの肌色輝度分布に応じたヒストグラム変換型階調補正回路制御信号を作成し電圧または電流に変換して出力する。出力されたヒストグラム変換型階調補正回路制御信号はヒストグラム変換型階調補正回路１０３に入力され、ヒストグラム変換型階調補正回路制御信号に応じたヒストグラム変換型階調補正を映像信号の輝度信号に掛ける。また出力されたヒストグラム変換型階調補正回路制御信号は色飽和度補正回路制御装置３０４に入力され、ヒストグラム変換型階調補正回路制御信号に応じた色飽和度補正回路制御信号を作成し電圧または電流に変換して出力する。出力された色飽和度補正回路制御信号は色飽和度補正回路３０５に入力され、色飽和度補正回路制御信号に応じた色飽和度補正を映像信号の色差信号に掛ける。
【００１８】
以上のように本実施の形態３によれば１フレームの肌色部分の輝度分布を検出することで映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正が可能となり、またそのヒストグラム変換型階調補正に応じた最適な色飽和度補正が可能となる。
【００１９】
（実施の形態４）
図４は本発明の一実施例における映像信号補正回路のブロック構成図を示す。図４において、上記実施の形態３と構成が異なる点は、肌色輝度分布検出回路１０１に加えて輝度分布検出回路６を備え、肌色輝度分布検出回路１の出力に加えて輝度分布検出回路６の出力をヒストグラム変換型階調補正回路制御装置の入力とした構成としていることである。輝度分布検出回路２０６は輝度信号から１フレーム中の輝度分布を検出する。他の構成については実施の形態３と同様なので説明を省略する。
【００２０】
以上のように構成された映像信号補正回路について以下その動作説明を行う。まず、図４における肌色輝度分布検出回路１０１において映像信号から１フレーム中の肌色部分の輝度分布を検出し、検出した結果を電圧に変換する。なお、検出回路の出力は電圧だけでなく電流でも良いことはいうまでもない。また図４における輝度分布検出回路２０６において映像信号から１フレーム中の輝度分布を検出し、検出した結果を電圧または電流に変換する。検出された肌色部分の輝度分布と輝度分布を図４におけるヒストグラム変換型階調補正回路制御装置２０２に入力し１フレーム中の映像信号の肌色部分の輝度分布と１フレーム中の輝度分布に応じたヒストグラム変換型階調補正回路制御信号を作成し電圧または電流に変換して出力する。出力されたヒストグラム変換型階調補正回路制御信号はヒストグラム変換型階調補正回路１０３に入力され、ヒストグラム変換型階調補正回路制御信号に応じたヒストグラム変換型階調補正を映像信号の輝度信号に掛ける。また出力されたヒストグラム変換型階調補正回路制御信号は色飽和度補正回路制御装置３０４に入力され、ヒストグラム変換型階調補正回路制御信号に応じた色飽和度補正回路制御信号を作成し電圧または電流に変換して出力する。出力された色飽和度補正回路制御信号は色飽和度補正回路３０５に入力され、色飽和度補正回路制御信号に応じた色飽和度補正を映像信号の色差信号に掛ける。
【００２１】
以上のように本実施の形態４によれば１フレーム中の映像信号の肌色部分の輝度分布と１フレーム中の輝度分布を検出することで映像の肌色部分の輝度分布と輝度分布に応じた最適なヒストグラム変換型階調補正が可能となり、またそのヒストグラム変換型階調補正に応じた最適な色飽和度補正が可能となる。
【００２２】
（実施の形態５）
図５は本発明の一実施例におけるヒストグラム変換型階調補正回路制御装置のブロック構成図を示す。本実施の形態においては、図８のように２つ以上に分割されたＮ個の分割輝度領域を有するヒストグラム変換型階調補正の場合を取り上げて説明する。
【００２３】
図５において、５０７は１フレーム中の輝度領域ｉより高輝度領域における肌色部分の輝度分布であるＰ［ｉ＋１］からＰ［Ｎ］を入力として前記１フレーム中の輝度領域ｉより高輝度領域における肌色部分の輝度分布Ｐ［ｉ＋１］からＰ［Ｎ］に応じてヒストグラム変換型階調補正傾きへ加える補正量を作成する傾き増加量演算回路であり、５０８は１フレーム中の前記輝度領域ｉより低輝度領域における肌色部分の輝度分布であるＰ［１］からＰ［ｉ−１］を入力として前記１フレーム中の前記輝度領域ｉより低輝度領域における肌色部分の輝度分布Ｐ［１］からＰ［ｉ−１］に応じてヒストグラム変換型階調補正基本傾きより減じる補正量を作成する傾き減少量演算回路であり、５０９は輝度領域ｉにおける映像信号に依存しないヒストグラム変換型階調補正基本傾きＢ［ｉ］と前記傾き増加量演算回路からの出力を入力とし演算結果を出力とする加算器であり、５１０は前記加算器の出力と前記傾き減少量演算回路からの出力を入力とし輝度領域ｉにおける肌色輝度分布適応ヒストグラム変換型階調補正傾きＧ［ｉ］を出力する減算器であり、５１１は全輝度領域における前記肌色輝度分布適応ヒストグラム変換型階調補正傾きを入力としてヒストグラム変換型階調補正回路制御信号を作成するヒストグラム変換型階調補正回路制御信号演算回路である。
また本発明の前記一実施の形態における映像信号補正回路は上記実施の形態１と同じであるので説明を省略する。
【００２４】
以上のように構成されたヒストグラム変換型階調補正回路制御装置について以下その動作説明を行う。
まず、輝度領域ｉにおける映像信号に依存しないヒストグラム変換型階調補正基本傾きＢ［ｉ］に対して、前記輝度領域ｉより高輝度領域における肌色部分の輝度分布Ｐ［ｉ＋１］からＰ［Ｎ］に応じて作成された傾き増加量演算回路５０７の出力を加え、前記輝度領域ｉより低輝度領域における肌色部分の輝度分布Ｐ［１］からＰ［ｉ−１］に応じて作成された傾き減少量演算回路５０８の出力を減じ、輝度領域ｉにおける肌色輝度分布適応ヒストグラム変換型階調補正傾きＧ［Ｉ］を作成し、これを電圧または電流に変換して出力する。なお、ヒストグラム変換型階調補正基本傾きＢ［１］に対する傾き減少量演算回路５０８の出力はゼロであり、ヒストグラム変換型階調補正基本傾きＢ［Ｎ］に対する傾き増加量演算回路５０７の出力はゼロであることは言うまでもない。
【００２５】
次に、出力された各輝度領域における肌色輝度分布適応ヒストグラム変換型階調補正傾きＧはヒストグラム変換型階調補正回路制御信号演算回路へ入力され、各輝度領域における肌色輝度分布適応ヒストグラム変換型階調補正傾きに応じたヒストグラム変換型階調補正回路制御信号を作成し電圧または電流に変換して出力する。
【００２６】
ヒストグラム変換型階調補正回路制御装置以外の動作は上記実施の形態１と同じであるので説明を省略する。
【００２７】
以上のように本実施の形態５によれば１フレーム中の肌色部分の輝度分布を検出することで映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正回路制御信号の作成を作成し、肌色部分の階調性を損なうことなく映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正が可能となる。
【００２８】
（実施の形態６）
図６は本発明の一実施例におけるヒストグラム変換型階調補正回路制御装置のブロック構成図を示す。本実施の形態においては、図８のように２つ以上に分割されたＮ個の分割輝度領域を有するヒストグラム変換型階調補正の場合を取り上げて説明する。
【００２９】
図６において、上記実施の形態５のヒストグラム変換型階調補正回路制御装置と構成が異なる点は、１フレーム中の輝度分布を入力として１フレーム中の輝度分布に応じた輝度分布適応ヒストグラム変換型階調補正傾きＨ［ｉ］を作成する輝度分布適応ヒストグラム変換型階調補正傾き演算回路６１２を備え、上記実施の形態５における映像信号に依存しないヒストグラム変換型階調補正基本傾きＢ［ｉ］を置き換えたことである。
【００３０】
ヒストグラム変換型階調補正回路制御装置に関する他の構成については実施の形態５と同様なので説明を省略する。
【００３１】
また本発明の前記一実施例における映像信号補正回路は上記実施の形態２と同じであるので説明を省略する。
【００３２】
以上のように構成されたヒストグラム変換型階調補正回路制御装置について以下その動作説明を行う。
まず、１フレーム中の輝度分布を入力として１フレーム中の輝度分布に応じた輝度分布適応ヒストグラム変換型階調補正傾きＨ［ｉ］を作成する輝度分布適応ヒストグラム変換型階調補正傾き演算回路６１２において１フレーム中の輝度分布に応じた輝度分布適応ヒストグラム変換型階調補正傾きＨ［ｉ］を作成し電圧または電流に変換して出力する。
【００３３】
次に、輝度領域ｉにおける輝度分布適応ヒストグラム変換型階調補正傾きＨ［ｉ］に対して、前記輝度領域ｉより高輝度領域における肌色部分の輝度分布であるＰ［ｉ＋１］からＰ［Ｎ］に応じて作成された傾き増加量演算回路５０７の出力を加え、前記輝度領域ｉより低輝度領域における肌色部分の輝度分布であるｐ［１］からＰ［ｉ−１］に応じて作成された傾き減少量演算回路５０８の出力を減じ、輝度領域ｉにおける肌色輝度分布適応ヒストグラム変換型階調補正傾きＧ［ｉ］を作成し、これを電圧または電流に変換して出力する。なお、ヒストグラム変換型階調補正基本傾きＨ［１］に対する傾き減少量演算回路５０８の出力はゼロであり、ヒストグラム変換型階調補正基本傾きＨ［Ｎ］に対する傾き増加量演算回路５０７の出力はゼロであることは言うまでもない。
【００３４】
次に、出力された各輝度領域における肌色輝度分布適応ヒストグラム変換型階調補正傾きＧはヒストグラム変換型階調補正回路制御信号演算回路へ入力され、各輝度領域における肌色輝度分布適応ヒストグラム変換型階調補正傾きに応じたヒストグラム変換型階調補正回路制御信号を作成し電圧または電流に変換して出力する。
【００３５】
ヒストグラム変換型階調補正回路制御装置以外の動作は上記実施の形態２と同じであるので説明を省略する。
【００３６】
以上のように本実施の形態６によれば１フレーム中の肌色部分の輝度分布と１フレーム中の輝度分布を検出することで映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正回路制御信号を作成し、肌色部分の階調性を損なうことなく映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正が可能となる。
【００３７】
（実施の形態７）
本発明の一実施例におけるヒストグラム変換型階調補正回路制御装置の構成は上記実施の形態５と同じであるので説明を省略する。
【００３８】
本発明の前記一実施例における映像信号補正回路は上記実施の形態３と同じであるので説明を省略する。
【００３９】
ヒストグラム変換型階調補正回路制御装置の動作は上記実施の形態５と同じであるので説明を省略する。
【００４０】
ヒストグラム変換型階調補正回路制御装置以外の動作は上記実施の形態３と同じであるので説明を省略する。
【００４１】
以上のように本実施の形態７によれば１フレーム中の肌色部分の輝度分布を検出することで映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正回路制御信号を作成し、肌色部分の階調性を損なうことなく映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正が可能となり、またそのヒストグラム変換型階調補正に応じた最適な色飽和度補正が可能となる。
【００４２】
（実施の形態８）
本発明の一実施例におけるヒストグラム変換型階調補正回路制御装置の構成は上記実施の形態６と同じであるので説明を省略する。
【００４３】
本発明の前記一実施例における映像信号補正回路は上記実施の形態４と同じであるので説明を省略する。
ヒストグラム変換型階調補正回路制御装置の動作は上記実施の形態６と同じであるので説明を省略する。
【００４４】
ヒストグラム変換型階調補正回路制御装置以外の動作は上記実施の形態４と同じであるので説明を省略する。
【００４５】
以上のように本実施の形態８によれば１フレーム中の肌色部分の輝度分布と１フレーム中の輝度分布を検出することで映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正回路制御信号を作成し、肌色部分の階調性を損なうことなく映像の肌色部分の輝度分布に応じた最適なヒストグラム変換型階調補正が可能となり、またそのヒストグラム変換型階調補正に応じた最適な色飽和度補正が可能となる。
【００４６】
【発明の効果】
以上のように本発明は、視聴者が映像信号の肌色部分の輝度分布と映像信号の輝度分布に応じた最適なヒストグラム変換型階調補正と色飽和度補正での視聴を可能とすることができ、その実用的効果は大きい。
【図面の簡単な説明】
【図１】本発明の第一の実施の形態および第五の実施の形態における映像信号補正回路のブロック構成図
【図２】本発明の第二の実施の形態および第六の実施の形態における映像信号補正回路のブロック構成図
【図３】本発明の第三の実施の形態および第七の実施の形態における映像信号補正回路のブロック構成図
【図４】本発明の第四の実施の形態および第八の実施の形態における映像信号補正回路のブロック構成図
【図５】本発明の第五の実施の形態および第七の実施の形態におけるヒストグラム変換型階調補正回路制御装置のブロック構成図
【図６】本発明の第六の実施の形態および第八の実施の形態におけるヒストグラム変換型階調補正回路制御装置のブロック構成図
【図７】従来の肌色輝度向上回路のブロック構成図
【図８】分割輝度領域の説明図
【符号の説明】
１０１肌色輝度分布検出回路
１０２、２０２ヒストグラム変換型階調補正回路制御装置
１０３ヒストグラム変換型階調補正回路
３０４色飽和度補正回路制御装置
３０５色飽和度補正回路
２０６輝度分布検出回路
５０７傾き増加量演算回路
５０８傾き減少量演算回路
５０９加算器
５１０減算器
５１１ヒストグラム変換型階調補正回路制御信号演算回路
５１２輝度分布適応ヒストグラム変換型階調補正傾き演算回路[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to control of a histogram conversion type gradation correction circuit and a color saturation correction circuit, and more particularly, to a circuit for controlling a histogram conversion type gradation correction circuit and a color saturation correction circuit according to the luminance distribution of a flesh color portion of a video signal. The present invention relates to a video signal correction circuit.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there has been a remarkable increase in the size of a television screen. In particular, human eyes are sensitive to the reproduction of human skin, and the gradation of human skin greatly affects image quality.
[0003]
FIG. 7 shows a block diagram of a conventional skin color luminance improving circuit (for example, Patent Document 1). The video signal correction circuit control device detects a skin color area in one frame from the color difference signal of the video signal, and an average luminance level of the skin color portion in one frame from the color difference signal and the luminance signal of the video signal. , An average luminance level detection circuit 703 that detects an average luminance level of one frame from a luminance signal of a video signal, an output from the skin color area detection circuit, and the skin color average luminance level detection The output from the circuit and the output from the average luminance level detection circuit are input, and the gamma correction circuit control signal corresponding to the area of the skin color part of one frame, the average luminance level of the skin color part of one frame, and the average luminance level of one frame is obtained. A gamma correction circuit control device 704 to be created, and a gamma correction circuit using an output from the gamma correction circuit control device as an input. Gamma adjustment according to a control signal which is a configuration that includes a gamma correction circuit 705 to be applied to the luminance signal of the video signal.
[0004]
In the conventional flesh color luminance improving circuit configured as described above, the flesh color darkened due to the side effect of the ACL for adjusting the beam amount of the CRT of the television set and the black extension correction for adjusting the black level of the video signal is provided. The luminance level is improved according to the average luminance level of the video signal and the average luminance level of the flesh color portion.
[0005]
[Patent Document 1]
JP-A-7-288839
[Problems to be solved by the invention]
However, in the above-described configuration, only the correction is performed with the average luminance level of the video signal and the average luminance level of the flesh color part, and the luminance distribution of the flesh color part is largely divided into both high luminance side and low luminance side. When the concentration is concentrated on the medium and medium luminances, the average luminance of the flesh color part is in the middle luminance range, so that it is not possible to distinguish between the two, and the luminance level of the flesh color part is improved and the gradation of the flesh color part is impaired Therefore, it was not possible to perform appropriate video signal correction according to the luminance distribution of the skin color.
[0007]
In view of the above, an object of the present invention is to provide a video signal correction circuit that enables a viewer to view a television in an optimum video signal correction state according to a video state.
[0008]
[Means for Solving the Problems]
A skin color luminance distribution detecting circuit for detecting a luminance distribution of a skin color portion in one frame from a color difference signal and a luminance signal of a video signal, a luminance distribution detecting circuit for detecting a luminance distribution in one frame from a luminance signal of the video signal, The output of the skin color luminance distribution detecting circuit and the output of the luminance distribution detecting circuit are input, and the luminance distribution of the flesh color portion of the video signal in one frame and the histogram conversion type gradation correction circuit control according to the luminance distribution in one frame A histogram conversion type gradation correction circuit control device for generating a signal; and an output from the histogram conversion type gradation correction circuit control device as an input, and performing gradation correction corresponding to the histogram conversion type gradation correction circuit control signal to a luminance signal. A histogram conversion type gradation correction circuit to be multiplied, and a histogram conversion type gradation correction circuit which receives an output from the histogram conversion type gradation correction circuit control device as an input. A color saturation correction circuit control device for generating a color saturation correction circuit control signal in accordance with a tone correction circuit control signal; and a color saturation correction circuit control using an output from the color saturation correction circuit control device and a luminance signal as inputs. The configuration is provided with a color saturation correction circuit that applies color saturation correction according to the signal to the color difference signal.
[0009]
According to the present invention, the output of the skin color luminance distribution detecting circuit for detecting the luminance distribution of the flesh color portion in one frame from the color difference signal and the luminance signal of the video signal and the luminance distribution in one frame from the luminance signal of the video signal can be obtained. The image state is calculated by the histogram conversion type gradation correction circuit control device from the former or both of the output of the luminance distribution detection circuit to be detected, and the histogram conversion type gradation correction circuit control device according to the histogram conversion type gradation correction circuit control device. Creates a correction circuit control signal, performs optimal histogram conversion type gradation correction according to the state of the video signal based on an output signal from the histogram conversion type gradation correction circuit control device, and, in some cases, color saturation correction circuit control device A color saturation correction circuit control signal corresponding to the output signal from the histogram conversion type gradation correction circuit control device is created, Perform optimum color saturation correction in accordance with the output signal from the histogram conversion type gradation correction circuit controller by the output signal from the saturation correction circuit controller.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
FIG. 1 shows a video signal correction circuit according to one embodiment of the present invention. In FIG. 1, reference numeral 101 denotes a flesh color luminance distribution detecting circuit for detecting a flesh color luminance distribution of a flesh color portion in one frame from a video signal, and 102 denotes a flesh color luminance distribution of one frame by using an output from the flesh color luminance distribution detecting circuit as an input. A histogram conversion type gradation correction circuit control device for generating a corresponding histogram conversion type gradation correction circuit control signal, and 103 receiving the output from the histogram conversion type gradation correction circuit control device as an input. This is a histogram conversion type gradation correction circuit that applies gradation correction according to a circuit control signal to a luminance signal.
[0011]
The operation of the video signal correction circuit configured as described above will be described below. First, the skin color luminance distribution detecting circuit 101 in FIG. 1 detects the luminance distribution of a flesh color portion in one frame from a video signal, and converts the detection result into a voltage. It goes without saying that the output of the detection circuit may be a current as well as a voltage. The detected luminance distribution of the flesh color portion is input to the histogram conversion type gradation correction circuit control device 102 in FIG. 1, and a histogram conversion type gradation correction circuit control signal corresponding to the flesh color luminance distribution of one frame is created to generate a voltage or a current. Convert and output. The output histogram conversion type gradation correction circuit control signal is input to the histogram conversion type gradation correction circuit 103, and the histogram conversion type gradation correction according to the histogram conversion type gradation correction circuit control signal is applied to the luminance signal of the video signal. Multiply.
[0012]
As described above, according to the first embodiment, by detecting the luminance distribution of the flesh color portion of one frame, it is possible to perform optimal histogram conversion type gradation correction according to the luminance distribution of the flesh color portion of the video.
[0013]
(Embodiment 2)
FIG. 2 is a block diagram of a video signal correction circuit according to one embodiment of the present invention. In FIG. 2, the difference from the first embodiment is that a luminance distribution detection circuit 206 is provided in addition to the skin color luminance distribution detection circuit 101, and the luminance distribution detection circuit 206 The configuration is such that the output is input to the histogram conversion type gradation correction circuit control device 202. The luminance distribution detection circuit 206 detects a luminance distribution in one frame from the luminance signal. The other configuration is the same as that of the first embodiment, and the description is omitted.
[0014]
The operation of the video signal correction circuit configured as described above will be described below. First, the skin color luminance distribution detection circuit 101 in FIG. 2 detects a luminance distribution of a flesh color portion in one frame from a video signal, and converts the detection result into a voltage. It goes without saying that the output of the detection circuit may be a current as well as a voltage. A luminance distribution detection circuit 206 in FIG. 2 detects a luminance distribution in one frame from a video signal, and converts the detection result into a voltage or a current. The luminance distribution and the luminance distribution of the detected flesh color portion are input to the histogram conversion type gradation correction circuit control device 202 in FIG. 2 and the luminance distribution of the flesh color portion of the video signal in one frame and the luminance distribution in one frame are determined. A histogram conversion type gradation correction circuit control signal is created, converted into a voltage or a current, and output. The output histogram conversion type gradation correction circuit control signal is input to the histogram conversion type gradation correction circuit 103, and the histogram conversion type gradation correction according to the histogram conversion type gradation correction circuit control signal is applied to the luminance signal of the video signal. Multiply.
[0015]
As described above, according to the second embodiment, the luminance distribution of the flesh-color portion of the video signal in one frame and the luminance distribution of the flesh-color portion of the video signal are detected, so that the luminance distribution of the flesh-color portion of the video and the optimal distribution according to the luminance distribution are detected. This makes it possible to perform a histogram conversion type gradation correction.
[0016]
(Embodiment 3)
FIG. 3 is a block diagram showing a video signal correction circuit according to one embodiment of the present invention. In FIG. 3, reference numeral 101 denotes a flesh color luminance distribution detecting circuit for detecting a flesh color luminance distribution of a flesh color portion in one frame from a video signal, and 102 denotes a flesh color luminance distribution of one frame by using an output from the flesh color luminance distribution detecting circuit as an input. A histogram conversion type gradation correction circuit control device for generating a corresponding histogram conversion type gradation correction circuit control signal, and 103 receiving the output from the histogram conversion type gradation correction circuit control device as an input. Reference numeral 304 denotes a histogram conversion type gradation correction circuit which multiplies the luminance signal by gradation correction according to the circuit control signal, and 304 receives the output from the histogram conversion type gradation correction circuit control device and controls the histogram conversion type gradation correction circuit. A color saturation correction circuit control device for generating a color saturation correction circuit control signal according to the signal; The output and color saturation correction in accordance with the color saturation correction circuit control signal a luminance signal as an input from degrees correction circuit controller of the color saturation correction circuit multiplying the color difference signal.
[0017]
The operation of the video signal correction circuit configured as described above will be described below. First, the skin color luminance distribution detection circuit 101 in FIG. 3 detects a luminance distribution of a flesh color portion in one frame from a video signal, and converts the detection result into a voltage. It goes without saying that the output of the detection circuit may be a current as well as a voltage. The detected luminance distribution of the flesh color portion is input to the histogram conversion type gradation correction circuit control device 102 in FIG. 3 to create a histogram conversion type gradation correction circuit control signal corresponding to the flesh color luminance distribution of one frame, and to generate a voltage or a current. Convert and output. The output histogram conversion type gradation correction circuit control signal is input to the histogram conversion type gradation correction circuit 103, and the histogram conversion type gradation correction according to the histogram conversion type gradation correction circuit control signal is applied to the luminance signal of the video signal. Multiply. The output histogram conversion type gradation correction circuit control signal is input to the color saturation correction circuit control device 304, and a color saturation correction circuit control signal corresponding to the histogram conversion type gradation correction circuit control signal is created to generate a voltage or Convert to current and output. The output color saturation correction circuit control signal is input to the color saturation correction circuit 305, and is subjected to color saturation correction according to the color saturation correction circuit control signal to the color difference signal of the video signal.
[0018]
As described above, according to the third embodiment, by detecting the luminance distribution of the flesh-color portion of one frame, it is possible to perform the optimum histogram conversion type gradation correction according to the luminance distribution of the flesh-color portion of the video. Optimum color saturation correction according to the conversion type gradation correction can be performed.
[0019]
(Embodiment 4)
FIG. 4 is a block diagram of a video signal correction circuit according to an embodiment of the present invention. 4 is different from the third embodiment in that a luminance distribution detecting circuit 6 is provided in addition to the flesh color luminance distribution detecting circuit 101, and the luminance distribution detecting circuit 6 The configuration is such that the output is input to the histogram conversion type gradation correction circuit control device. The luminance distribution detection circuit 206 detects a luminance distribution in one frame from the luminance signal. The other configuration is the same as that of the third embodiment, and the description is omitted.
[0020]
The operation of the video signal correction circuit configured as described above will be described below. First, the skin color luminance distribution detection circuit 101 in FIG. 4 detects a luminance distribution of a flesh color portion in one frame from a video signal, and converts the detection result into a voltage. It goes without saying that the output of the detection circuit may be a current as well as a voltage. The luminance distribution detection circuit 206 in FIG. 4 detects the luminance distribution in one frame from the video signal, and converts the detection result into a voltage or a current. The luminance distribution and the luminance distribution of the detected flesh color portion are input to the histogram conversion type gradation correction circuit control device 202 in FIG. 4, and the luminance distribution of the flesh color portion of the video signal in one frame and the luminance distribution in one frame are determined. A histogram conversion type gradation correction circuit control signal is created, converted into a voltage or a current, and output. The output histogram conversion type gradation correction circuit control signal is input to the histogram conversion type gradation correction circuit 103, and the histogram conversion type gradation correction according to the histogram conversion type gradation correction circuit control signal is applied to the luminance signal of the video signal. Multiply. The output histogram conversion type gradation correction circuit control signal is input to the color saturation correction circuit control device 304, and a color saturation correction circuit control signal corresponding to the histogram conversion type gradation correction circuit control signal is created to generate a voltage or Convert to current and output. The output color saturation correction circuit control signal is input to the color saturation correction circuit 305, and is subjected to color saturation correction according to the color saturation correction circuit control signal to the color difference signal of the video signal.
[0021]
As described above, according to the fourth embodiment, the luminance distribution of the flesh color portion of the video signal in one frame and the luminance distribution of the flesh color portion in one frame are detected, so that the luminance distribution of the flesh color portion of the video and the optimal distribution according to the luminance distribution are obtained. Histogram conversion type gradation correction, and optimal color saturation correction in accordance with the histogram conversion type gradation correction.
[0022]
(Embodiment 5)
FIG. 5 is a block diagram of a histogram conversion type gradation correction circuit control device according to an embodiment of the present invention. In the present embodiment, a case of a histogram conversion type gradation correction having N divided luminance regions divided into two or more as shown in FIG. 8 will be described.
[0023]
In FIG. 5, reference numeral 507 denotes an input of P [i + 1] to P [N], which are the luminance distribution of the flesh color portion in the luminance region higher than the luminance region i in one frame, in the luminance region higher than the luminance region i in the frame. A slope increase amount calculation circuit for creating a correction amount to be added to the histogram conversion type gradation correction slope in accordance with the brightness distribution P [i + 1] to P [N] of the flesh color portion. The luminance distributions P [1] to P [i-1] of the skin color portion in the low luminance region are input and the luminance distributions P [1] to P of the skin color portion in the luminance region lower than the luminance region i in the one frame. A slope reduction amount calculation circuit that creates a correction amount that is smaller than the histogram conversion type gradation correction basic slope in accordance with [i-1]. Reference numeral 509 denotes a hiss independent of the video signal in the luminance area i. An adder which receives the output of the Gram conversion type gradation correction basic slope B [i] and the output from the slope increase calculation circuit and outputs the calculation result; and 510, the output of the adder and the slope decrease calculation circuit 511 is a subtractor that receives the output of the above as an input, and outputs the skin color luminance distribution adaptive histogram conversion type gradation correction gradient G [i] in the luminance region i. This is a histogram conversion-type gradation correction circuit control signal operation circuit that creates a histogram conversion-type gradation correction circuit control signal by using an inclination as an input.
Further, the video signal correction circuit according to the one embodiment of the present invention is the same as that of the first embodiment, and the description is omitted.
[0024]
The operation of the histogram conversion type gradation correction circuit control device configured as described above will be described below.
First, for the histogram conversion type gradation correction basic slope B [i] that does not depend on the video signal in the luminance area i, the luminance distributions P [i + 1] to P [N] of the skin color portion in the luminance area higher than the luminance area i. The output of the slope increase amount calculation circuit 507 created according to the above is added, and the slope decrease created according to the brightness distributions P [1] to P [i-1] of the skin color portions in the brightness region lower than the brightness region i is added. The output of the quantity calculation circuit 508 is reduced to create a skin color luminance distribution adaptive histogram conversion type gradation correction gradient G [I] in the luminance area i, which is converted into a voltage or a current and output. Note that the output of the slope decrease amount calculation circuit 508 for the histogram conversion type gradation correction basic slope B [1] is zero, and the output of the slope increase amount calculation circuit 507 for the histogram conversion type gradation correction basic slope B [N] is It goes without saying that it is zero.
[0025]
Next, the output skin color luminance distribution adaptive histogram conversion type gradation correction slope G in each luminance region is input to a histogram conversion type gradation correction circuit control signal calculation circuit, and the skin color luminance distribution adaptive histogram conversion type floor scale in each luminance region is output. A histogram conversion type gradation correction circuit control signal corresponding to the gradation correction inclination is created, converted into a voltage or a current, and output.
[0026]
Operations other than the histogram conversion type gradation correction circuit control device are the same as those in the first embodiment, and thus description thereof is omitted.
[0027]
As described above, according to the fifth embodiment, by detecting the luminance distribution of the flesh color portion in one frame, it is possible to generate an optimum histogram conversion type gradation correction circuit control signal according to the luminance distribution of the flesh color portion of the video. This makes it possible to perform optimum histogram conversion type gradation correction according to the luminance distribution of the skin color portion of the video without impairing the gradation characteristics of the skin color portion.
[0028]
(Embodiment 6)
FIG. 6 is a block diagram showing a histogram conversion type gradation correction circuit control device according to an embodiment of the present invention. In the present embodiment, a case of a histogram conversion type gradation correction having N divided luminance regions divided into two or more as shown in FIG. 8 will be described.
[0029]
In FIG. 6, the difference from the histogram conversion type gradation correction circuit control device of the fifth embodiment is that the luminance distribution adaptive histogram conversion type according to the luminance distribution in one frame with the luminance distribution in one frame as input. A luminance distribution adaptive histogram conversion type gradation correction inclination calculation circuit 612 for generating the gradation correction inclination H [i] is provided, and the histogram conversion type gradation correction basic inclination B [i] independent of the video signal according to the fifth embodiment. Has been replaced.
[0030]
The other configuration relating to the histogram conversion type gradation correction circuit control device is the same as that of the fifth embodiment, and thus the description is omitted.
[0031]
Further, the video signal correction circuit in the one embodiment of the present invention is the same as that in the second embodiment, and the description is omitted.
[0032]
The operation of the histogram conversion type gradation correction circuit control device configured as described above will be described below.
First, a luminance distribution adaptive histogram conversion type gradation correction inclination calculating circuit 612 for generating a luminance distribution adaptive histogram conversion type gradation correction inclination H [i] corresponding to the luminance distribution in one frame by using the luminance distribution in one frame as an input. , A luminance distribution adaptive histogram conversion type gradation correction gradient H [i] corresponding to the luminance distribution in one frame is created, converted into a voltage or a current, and output.
[0033]
Next, with respect to the luminance distribution adaptive histogram conversion type gradation correction gradient H [i] in the luminance region i, P [i + 1] to P [N] which are the luminance distribution of the skin color portion in the luminance region higher than the luminance region i. The output of the slope increase amount calculation circuit 507 created according to the above is added, and it is created according to the luminance distributions p [1] to P [i-1] of the skin color portion in the luminance region lower than the luminance region i. The output of the slope decrease amount calculation circuit 508 is reduced to create a skin color brightness distribution adaptive histogram conversion type gradation correction slope G [i] in the brightness area i, which is converted into a voltage or a current and output. Note that the output of the slope decrease amount calculation circuit 508 for the histogram conversion type gradation correction basic slope H [1] is zero, and the output of the slope increase amount calculation circuit 507 for the histogram conversion type gradation correction basic slope H [N] is It goes without saying that it is zero.
[0034]
Next, the output skin color luminance distribution adaptive histogram conversion type gradation correction slope G in each luminance region is input to a histogram conversion type gradation correction circuit control signal calculation circuit, and the skin color luminance distribution adaptive histogram conversion type floor scale in each luminance region is output. A histogram conversion type gradation correction circuit control signal corresponding to the gradation correction inclination is created, converted into a voltage or a current, and output.
[0035]
The operations other than the histogram conversion type gradation correction circuit control device are the same as those in the second embodiment, and therefore the description is omitted.
[0036]
As described above, according to the sixth embodiment, by detecting the luminance distribution of the flesh color portion in one frame and the luminance distribution in one frame, the optimum histogram conversion type gradation corresponding to the luminance distribution of the flesh color portion of the video is obtained. By generating a correction circuit control signal, it is possible to perform optimum histogram conversion type gradation correction according to the luminance distribution of the skin color portion of the video without impairing the gradation characteristics of the skin color portion.
[0037]
(Embodiment 7)
The configuration of the histogram conversion type gradation correction circuit control device according to one embodiment of the present invention is the same as that of the fifth embodiment, and the description is omitted.
[0038]
The video signal correction circuit in the one embodiment of the present invention is the same as that in the third embodiment, and the description is omitted.
[0039]
The operation of the histogram conversion-type gradation correction circuit control device is the same as that of the fifth embodiment, and a description thereof will be omitted.
[0040]
Operations other than the histogram conversion type gradation correction circuit control device are the same as those in the third embodiment, and thus description thereof is omitted.
[0041]
As described above, according to the seventh embodiment, the optimum histogram conversion type gradation correction circuit control signal corresponding to the luminance distribution of the flesh color portion of the video is created by detecting the luminance distribution of the flesh color portion in one frame. Optimum histogram conversion type gradation correction according to the luminance distribution of the skin color portion of the video is possible without impairing the gradation characteristics of the skin color portion, and optimal color saturation correction according to the histogram conversion type gradation correction Becomes possible.
[0042]
(Embodiment 8)
The configuration of the histogram conversion type gradation correction circuit control device according to one embodiment of the present invention is the same as that of the sixth embodiment, and a description thereof will be omitted.
[0043]
The video signal correction circuit according to the one embodiment of the present invention is the same as that of the fourth embodiment, and the description is omitted.
The operation of the histogram conversion-type gradation correction circuit control device is the same as that of the sixth embodiment, and a description thereof will be omitted.
[0044]
Operations other than the histogram conversion type gradation correction circuit control device are the same as those in the above-described fourth embodiment, and a description thereof will be omitted.
[0045]
As described above, according to the eighth embodiment, the luminance distribution of the flesh color portion in one frame and the luminance distribution of the flesh color portion in one frame are detected, so that the optimum histogram conversion type gradation corresponding to the luminance distribution of the flesh color portion of the image is obtained. By creating a correction circuit control signal, it is possible to perform optimal histogram conversion type gradation correction according to the luminance distribution of the skin color part of the video without impairing the gradation property of the skin color part, and according to the histogram conversion type gradation correction This makes it possible to perform optimal color saturation correction.
[0046]
【The invention's effect】
As described above, the present invention makes it possible for a viewer to view with the optimal histogram conversion type gradation correction and color saturation correction according to the luminance distribution of the flesh color portion of the video signal and the luminance distribution of the video signal. Yes, its practical effect is great.
[Brief description of the drawings]
FIG. 1 is a block diagram of a video signal correction circuit according to a first embodiment and a fifth embodiment of the present invention. FIG. 2 is a block diagram of a video signal correction circuit according to a second embodiment and a sixth embodiment of the present invention. FIG. 3 is a block diagram of a video signal correction circuit according to the third and seventh embodiments of the present invention. FIG. 4 is a block diagram of a video signal correction circuit according to a fourth embodiment of the present invention. FIG. 5 is a block diagram of a video signal correction circuit according to the eighth and eighth embodiments. FIG. 5 is a block diagram of a histogram conversion type gradation correction circuit control device according to a fifth embodiment and a seventh embodiment of the present invention. FIG. 6 is a block diagram of a histogram conversion type gradation correction circuit control device according to a sixth embodiment and an eighth embodiment of the present invention. FIG. 7 is a block diagram of a conventional skin color luminance improvement circuit. 8) Split Illustration of degrees area [Description of symbols]
101 Skin color luminance distribution detection circuit 102, 202 Histogram conversion type gradation correction circuit control device 103 Histogram conversion type gradation correction circuit 304 Color saturation correction circuit control device 305 Color saturation correction circuit 206 Luminance distribution detection circuit 507 Slope increase calculation Circuit 508 Slope decrease amount calculation circuit 509 Adder 510 Subtractor 511 Histogram conversion type gradation correction circuit Control signal calculation circuit 512 Luminance distribution adaptive histogram conversion type gradation correction inclination calculation circuit

Claims

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a flesh color portion in one frame from a color difference signal and a luminance signal of a video signal, and a histogram corresponding to a flesh color luminance distribution of one frame by using an output from the flesh color luminance distribution detecting circuit as an input A first histogram conversion type gradation correction circuit control device for generating a conversion type gradation correction circuit control signal, and a histogram conversion type gradation correction circuit control signal which receives an output from the histogram conversion type gradation correction circuit control device as an input. A histogram conversion type gradation correction circuit for applying a gradation correction to the luminance signal according to the luminance signal of the video signal in accordance with the luminance distribution of the flesh color portion of the video signal in one frame. Characteristic video signal correction circuit.

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a skin color portion in one frame from a color difference signal and a luminance signal of a video signal, a luminance distribution detecting circuit for detecting a luminance distribution in one frame from a luminance signal of the video signal, The output of the skin color luminance distribution detecting circuit and the output of the luminance distribution detecting circuit are input, and the luminance distribution of the flesh color portion of the video signal in one frame and the histogram conversion type gradation correction circuit control according to the luminance distribution in one frame A second histogram conversion type tone correction circuit control device for generating a signal, and a tone correction according to the histogram conversion type tone correction circuit control signal, using an output from the histogram conversion type tone correction circuit control device as an input. A histogram conversion type gradation correction circuit for multiplying the luminance signal is provided, and the luminance distribution of the flesh color portion of the video signal in one frame and the luminance distribution in one frame are adjusted. Video signal correction circuit, characterized in that multiplying the histogram conversion type gradation correction on the luminance signal of the video signal Te.

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a flesh color portion in one frame from a color difference signal and a luminance signal of a video signal, and a histogram corresponding to a flesh color luminance distribution of one frame by using an output from the flesh color luminance distribution detecting circuit as an input A first histogram conversion type gradation correction circuit control device for generating a conversion type gradation correction circuit control signal, and a histogram conversion type gradation correction circuit control signal which receives an output from the histogram conversion type gradation correction circuit control device as an input. A histogram conversion type gradation correction circuit for applying a gradation correction according to the luminance signal to the luminance signal, and a color saturation according to the histogram conversion type gradation correction circuit control signal with an output from the histogram conversion type gradation correction circuit control device as an input. A color saturation correction circuit control device for generating a color correction circuit control signal, and an output and a luminance signal from the color saturation correction circuit control device. A color saturation correction circuit for applying a color saturation correction according to the control signal to the color difference signal, and converting the luminance signal of the video signal into a luminance signal of a flesh color portion of the video signal in one frame. A video signal correction circuit, wherein the color difference signal of the video signal is corrected by applying a histogram conversion type gradation correction.

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a skin color portion in one frame from a color difference signal and a luminance signal of a video signal, a luminance distribution detecting circuit for detecting a luminance distribution in one frame from a luminance signal of the video signal, The output of the skin color luminance distribution detecting circuit and the output of the luminance distribution detecting circuit are input, and the luminance distribution of the flesh color portion of the video signal in one frame and the histogram conversion type gradation correction circuit control according to the luminance distribution in one frame A second histogram conversion type tone correction circuit control device for generating a signal, and a tone correction according to the histogram conversion type tone correction circuit control signal, using an output from the histogram conversion type tone correction circuit control device as an input. A histogram conversion type gradation correction circuit for multiplying a luminance signal; and a histogram which receives an output from the histogram conversion type gradation correction circuit control device as an input. A color saturation correction circuit control device for creating a color saturation correction circuit control signal corresponding to the conversion type gradation correction circuit control signal; A color saturation correction circuit for multiplying the color difference signal by a color saturation correction according to a correction circuit control signal, wherein a luminance distribution of a flesh color portion of the video signal in one frame and a luminance distribution of the video signal according to a luminance distribution in one frame are provided. A video signal correction circuit, wherein a luminance signal is subjected to a histogram conversion type gradation correction and a color difference signal of the video signal is corrected.

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a flesh color portion in one frame from a color difference signal and a luminance signal of a video signal, and a histogram conversion type for arbitrary luminance in one frame by using an output from the flesh color luminance distribution detecting circuit as an input A histogram conversion type gradation correction circuit control in which a gradation correction inclination is increased according to a luminance distribution of a skin color portion in a higher luminance region than the arbitrary luminance and is decreased according to a luminance distribution of a skin color portion in a lower luminance region than the arbitrary luminance. A third histogram conversion type gradation correction circuit control device for generating a signal, and a gradation correction corresponding to the histogram conversion type gradation correction circuit control signal with an output from the histogram conversion type gradation correction circuit control device as an input. A histogram conversion type gradation correction circuit for multiplying the luminance signal is provided, according to the luminance distribution of the flesh color portion of the video signal in one frame. Video signal correction circuit, characterized in that multiplying the histogram conversion type gradation correction on the luminance signal of the image signal.

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a skin color portion in one frame from a color difference signal and a luminance signal of a video signal, a luminance distribution detecting circuit for detecting a luminance distribution in one frame from a luminance signal of the video signal, A histogram conversion type gradation correction circuit control signal created in accordance with a luminance distribution in one frame with an output from the skin color luminance distribution detecting circuit and an output from the luminance distribution detecting circuit as inputs, and further, an arbitrary luminance in one frame The histogram conversion type gradation correction slope corresponding to is increased according to the luminance distribution of the flesh color portion in the higher luminance region than the arbitrary luminance and decreased according to the luminance distribution of the flesh color portion in the lower luminance region than the arbitrary luminance. A fourth histogram conversion type gradation correction circuit control device for generating a tone correction circuit control signal; A histogram conversion type gradation correction circuit for applying a gradation correction according to a control signal to a luminance signal with an output from the road control device as an input, and a histogram conversion type gradation correction circuit for a flesh color portion of a video signal in one frame. A video signal correction circuit, which performs a histogram conversion type gradation correction on a luminance signal of a video signal according to a luminance distribution and a luminance distribution in one frame.

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a flesh color portion in one frame from a color difference signal and a luminance signal of a video signal, and a histogram conversion type for arbitrary luminance in one frame by using an output from the flesh color luminance distribution detecting circuit as an input A histogram conversion type gradation correction circuit control in which a gradation correction inclination is increased according to a luminance distribution of a skin color portion in a higher luminance region than the arbitrary luminance and is decreased according to a luminance distribution of a skin color portion in a lower luminance region than the arbitrary luminance. A third histogram conversion type gradation correction circuit control device for generating a signal, and a gradation correction corresponding to the histogram conversion type gradation correction circuit control signal with an output from the histogram conversion type gradation correction circuit control device as an input. A histogram conversion type gradation correction circuit for multiplying a luminance signal and an output from the histogram conversion type gradation correction circuit control device are inputted. A color saturation correction circuit control device that creates a color saturation correction circuit control signal according to a histogram conversion type gradation correction circuit control signal, and an output from the color saturation correction circuit control device and a luminance signal as an input. Saturation correction circuit A color saturation correction circuit for applying a color saturation correction according to a control signal to a color difference signal is provided, and a histogram conversion into a luminance signal of a video signal is performed according to a luminance distribution of a flesh color portion of a video signal in one frame. A video signal correction circuit, wherein a color difference signal of a video signal is corrected by applying a tone correction.

A skin color luminance distribution detecting circuit for detecting a luminance distribution of a skin color portion in one frame from a color difference signal and a luminance signal of a video signal, a luminance distribution detecting circuit for detecting a luminance distribution in one frame from a luminance signal of the video signal, A histogram conversion type gradation correction circuit control signal created in accordance with a luminance distribution in one frame with an output from the skin color luminance distribution detecting circuit and an output from the luminance distribution detecting circuit as inputs, and further, an arbitrary luminance in one frame The histogram conversion type gradation correction slope corresponding to is increased according to the luminance distribution of the flesh color portion in the higher luminance region than the arbitrary luminance and decreased according to the luminance distribution of the flesh color portion in the lower luminance region than the arbitrary luminance. A fourth histogram conversion type gradation correction circuit control device for generating a tone correction circuit control signal; A histogram conversion type gradation correction circuit for applying a gradation correction according to a histogram conversion type gradation correction circuit control signal to a luminance signal by using an output from the road control device as an input; and a histogram conversion type gradation correction circuit control device. A color saturation correction circuit control device that creates a color saturation correction circuit control signal according to a histogram conversion type gradation correction circuit control signal with an output as an input, and an output and a luminance signal from the color saturation correction circuit control device. A color saturation correction circuit for inputting a color saturation correction in accordance with a control signal to the color difference signal according to a control signal, to obtain a luminance distribution of a flesh color portion of a video signal in one frame and a luminance distribution in one frame; A video signal correction circuit, wherein the luminance signal of the video signal is subjected to histogram conversion type gradation correction in response to the correction of the color difference signal of the video signal.