Legacy ImageMagick Discussions Archive

Hi, I'm running IM 6.9.0-10 Q16 x64.

I have an image where I'd like to analyze a certain portion of the image. The portion is an irregular shape, so I cannot crop to the portion. I have decided to make all other pixels transparent, but doesn't care - it still analyzes the whole image, including the transparent pixels. If I set all the transparent pixels to white, or all to black, it obviously skews the mean up massively, or down massively, respectively. What am I to do!? I just want to know the mean value of the opaque pixels!

Any help would be very much appreciated.

Tom

see the "Better Method" at http://www.fmwconcepts.com/imagemagick/ ... shape_mean

After making all other pixels transparent, do
for range 0 to quantumrange

or
for range 0 to 255

for range 0 to 1

I didn't realise the -scale operator ignored all transparent values. That's really helpful. Thanks!