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How do I get "-selective-blur" to work faster?
Posted: 2012-01-08T13:50:13-07:00
by dev.alex89
How do I get "-selective-blur" and "gaussian-blur" to work faster? May by configure imagemagick, some options ?
Re: How do I get "-selective-blur" to work faster?
Posted: 2012-01-08T13:56:20-07:00
by 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.
Re: How do I get "-selective-blur" to work faster?
Posted: 2012-01-08T19:15:50-07:00
by 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.
Re: How do I get "-selective-blur" to work faster?
Posted: 2012-01-09T03:49:26-07:00
by dev.alex89
anthony thanks will try
fmw42 yes I known about Q8 but there is no effect on the speed