This function is
currently not documented; only the argument list is
available.
Warning:
This function is
EXPERIMENTAL. The behaviour of this function, the
name of this function, and anything else documented about this
function may change without notice in a future release of PHP.
Use this function at your own risk.
Adds blur filter to image. Optional third parameter to blur a specific channel.
Parameters
radius
Blur radius
sigma
Standard deviation
channel
The Channeltype constant. When not supplied, all channels are blurred.