How do I get "-selective-blur" to work faster?

[dev.alex89]

How do I get "-selective-blur" and "gaussian-blur" to work faster? May by configure imagemagick, some options ?

[fmw42]

Only possibility is to compile IM in Q8 format so that less memory is needed, but I am not sure that will help. There may be some other memory options that might help, but I am not an expert on those.

[anthony]

gaussian-blue is a single pass 2-dimention convolution, as such it it quite slow. A faster way is to just use -blur which is a 2-pass 1-dimentional blur.

For detailed low level examples of this see.. Gaussian vs Blur Kernels
http://www.imagemagick.org/Usage/convol ... an_vs_blur

For VERY VERY large gaussian blurs or convolution with non-gaussian shapes, you can switch to using a multiple of images in a Frequency Space (using Fast Fourier Transforms or FFT) see...
http://www.imagemagick.org/Usage/fourie ... /#multiply

Multiple of the double FFT images this is not built into ImageMagick

FUTURE: eventually we may get someone who will be able to add -fourier multiply of FFT images or even a more direct -blur-fourier of normal image as built in operators.

[dev.alex89]

anthony thanks will try

fmw42 yes I known about Q8 but there is no effect on the speed