Gimp effect (Value propagate) in ImageMagick

[rcosta]

Hello,

First sorry for my english, I'm portuguese.

I'm trying to apply an effect to an image in order to highlight a digital signature.

Already managed to achieve some results but still not what I wanted.

I'm doing the following treatment:

Code: Select all

convert teste.png -fuzz 10% -fill white -opaque '#C5E2FF' teste.png; 
mogrify -monochrome  teste.png
convert teste.png -morphology close diamond teste.png
mogrify -unsharp 0x3 teste.png

this is what I can achieve

screen capture windows 7

but if i use gimp and the filter "value propagate" i can enlarge the black area of signature like this

upload jpg

I've looked at all the available documentation and can not find a way to enlarge the black areas.

How can I achieve this effect using ImageMagick?

Thank you.

[fmw42]

Have you tried using diamond:2 or octagon:1 or octagon:2?