(バージョン情報なし。おそらく SVN 版にしか存在しないでしょう)
ImagickPixel::isPixelSimilarQuantum — Description
$color
[, string $fuzz
] )Returns true if the distance between two colors is less than the specified distance. The fuzz value should be in the range 0-QuantumRange. The maximum value represents the longest possible distance in the colorspace. e.g. from RGB(0, 0, 0) to RGB(255, 255, 255) for the RGB colorspace
color
fuzz