PHP Manual: Sharpens an image

Description

bool Imagick::unsharpMaskImage ( float $radius , float $sigma , float $amount , float $threshold [, int $channel = Imagick::CHANNEL_ALL ] )

Sharpens an image. We convolve the image with a Gaussian operator of the given radius and standard deviation (sigma). For reasonable results, radius should be larger than sigma. Use a radius of 0 and Imagick::UnsharpMaskImage() selects a suitable radius for you.

Parameters

radius
sigma
amount
threshold
channel

Return Values

Returns TRUE on success.

Errors/Exceptions

Throws ImagickException on error.