The RGB color
space is the default color space for most available image
formats. Any other color space can be obtained from a
linear or non-linear transformation from RGB. The color
space transformation is assumed to decrease the overlap
between skin and non-skin pixels thereby aiding skin-pixel
classification and to provide robust parameters against
varying illumination conditions. It has been observed that
skin colors differ more in intensity than in chrominance
[11]. Hence, it has been a common practice to drop the
luminance component for skin classification. Several color
spaces have been proposed and used for skin detection. In
this section, we review the most widely used color spaces
for skin detection and their properties.