bool Imagick::gaussianBlurImage    ( float $radius   , float $sigma   [, int $channel = Imagick::CHANNEL_DEFAULT  ] )

Imagick::gaussianBlurImageBlurs an image

radius

The radius of the Gaussian, in pixels, not counting the center pixel.

sigma

The standard deviation of the Gaussian, in pixels.

channel

Provide any channel constant that is valid for your channel mode. To apply to more than one channel, combine channeltype constants using bitwise operators. Refer to this list of channel constants.