PHP fastest way to apply strong blur

5
votes

I need to write a script to blur an image. That wouldn't be a problem if I didn't need it to blur it really hard.

Now, GD's gaussian blur filter is really weak. And imageconvolution accepts only 3x3 matrixes for some reason so I can't generate gaussian matrix with larger radius for stronger blur? Even if I could, I'm not sure how fast it would be.

Running gaussian blur multiple times does the trick, but is really slow. To achieve effect I'm searching for, I need to run it 40-100 times over an image, and, ofcourse, it takes 10-20 seconds to finish.

Is there a way to achieve what I'm looking for in reasonable time using libraries that come bundled with PHP?

Here is the exact effect. Generation time: 10.972307920456 seconds. 80 passes.

Original:

enter image description here

Processed:

enter image description here

1
phpimagegaussian
You could check how ImageMagick would perform. It has PHP native interface: imagemagick.org/Usage/blur – ddinchev
But I need it to come bundled with PHP, and it doesn't unfortunately. I would be really happy if somebody even knew about some extremely inaccurate but really fast algorithm which I could run over the image on per-pixel basis. – user2742648
But GD (what you are currently using) is NOT bundled with PHP. It just has wrapper for PHP much like IM... – ddinchev
You could check out stackblur filter and port it to PHP. – bitWorking
A differt approach you could try is to resize the image to 10% of its original size and then either blow it up again or just have the browser render it in it's original size. – Christiaan

1 Answers

0
votes

bool Imagick::blurImage ( float $radius , float $sigma [, int $channel ] )

a). $radius Blur radius

b). $sigma Standard deviation

c). $channel The Channeltype constant. When not supplied, all channels are blurred.