@techreport{oai:ipsj.ixsq.nii.ac.jp:00070202,
 author = {川村, 春美 and 米村, 俊一 and 大谷, 淳 and 松浦, 宣彦 and Harumi, Kawamura and Shunichi, Yonemura and Jun, Ohya and Norihiko, Matsuura},
 issue = {6},
 month = {Aug},
 note = {本報告では，色相に着目して灰色仮説に基づく照明光色の推定手法を提案する．灰色仮説は画像中の物体の色の平均を灰色であるとする仮説である．従来，この仮説を利用して画像の平均を照明光の色として推定する手法が提案されているが，仮説が成立しない場合には照明光の推定精度が悪くなるという問題があった．そこで，画素値を類似の色相をもつカテゴリに分類し，反対色の関係にある色相カテゴリから色を選択し灰色仮説の成立可否を判定することによって照明光の色を推定する手法を提案する．実験により，平均に偏りのある色分布に対しても本提案手法による推定照明光が従来手法に比較して正解値の近くに推定できること，推定誤差が人間が知覚できる色差よりも小さいことを示した．, This paper proposes a gray world assumption based method for estimating an illuminant color from an image by hue categorization. The gray world assumption hypothesizes that the average color of all the objects in a scene is gray. However, it is difficult to estimate an illuminant color correctly if the colors of the objects in a scene are dominated by certain colors. To solve this problem, our method roughly categorizes the colors in the image by hue and selects them one by one to decide whether the average of the selected colors can be regarded as an illuminant color or not. We use a surface reflectance set obtained from the object color spectra database and three illuminants, i.e., CIE standard illuminants A and D65, and blackbody radiation with 15000 K of color temperature, as an experiment for estimating an illuminant color. Experiment results show that estimated illuminants are closer to the correct one than that of the conventional one, and the estimation error by our method is within the just noticeable difference in human color perception.},
 title = {色相に着目した灰色仮説に基づく照明光推定法の一提案},
 year = {2010}
}