How to remove an image's solid background using ImageMagick convert command

I'm finding a way to make the solid background of an image become as transparent as possible (with little halo). ImageMagick is a powerful tool however it's not easy to use. I tried one command

convert image.jpg \
-bordercolor white \
-border 1x1 \
-alpha s开发者_开发问答et \
-channel RGBA \
-fuzz 20% \
-fill none \
-floodfill +0+0 white \
-shave 1x1 \
image.png

, which works kinda well. However, this requires me to know the exact color of the solid background while I need something to work with any background color. Anyone could help me with this? Th

As a heuristic, you could ask for the color of the pixels at the corners (http://studio.imagemagick.org/pipermail/magick-users/2005-March/015034.html) and then see which color is used the most. Not exactly fool-proof, though...