(PECL imagick 3 >= 3.3.0)
Imagick::setImageBiasQuantum — Sets the image bias
此函数在 Imagick 3.4.4 中被 废弃，强烈建议不要应用此函数。
$bias
Sets the image bias. Bias should be scaled with 0 (no adjustment) to 1 (quantum value).
0
1
bias
