[magick-users] Finging Face edges and remove backgrounds (correction)

[Claus Cyrny]

Claus Cyrny wrote:
> Hi Chris,
> 
> Chris Cinelli wrote:
>> Hi,
>>
>> I am trying to find an automated effective way to:
>>
>> 1) detect the face edges and minimize the details in the face (like nose
>> etc) in a portrait image.  The images are taken on white background 
>> but it may be a little gray and
>> have shadows. The ideal result would be an image that has in black thick
>> borders of the edges of the faces, the hair, eyebrows and a minimal 
>> details
>> of nose and mouth. Everything on a white background. Anybody can help 
>> with
>> that ?
>>
>> 2) remove the background and make that part of the image transparent. 
>> Again
>> it is still a portrait with a white-ish background.
> 
> 
> regarding the background part, I tried this successfully myself,
> albeit with a strictly white background. In your case, I would
> copy the image and paint over the face in a bitmap editor like
> Gimp etc. in order to remove the face completely and have just
> the background on a separate image. You can then proceed as
> follows (this is a shell script for Linux, but you can modify
> this easily for any other OS):
> 
> ----
> #!/bin/sh
> 
> convert image_with_face.extension -fuzz 25% -background.extension \
> -compose change-mask -composite final_image.extension
> 
> display final_image.extension
> ----

sorry, I found an error in the script. Actually, it should read:

#!/bin/sh

convert image_with_face.extension -fuzz 25% -transparent white 
background.extension \
-compose change-mask -composite final_image.extension

display final_image.extension

Besides that, I realized that on a background with shades
of white this will probably not work. One quick solution
in order to get a white background would be, to select the
background (with the quickmask inside a bitmap editor)
and change the levels/curves, until the background is just
white.

Claus


> 
> The last line is optional, of course. You may have
> to try out different valuers for '-fuzz'.
> 
> Here's an example from my blog (the text is in
> German, but I guess the image speaks for itself):
> 
> http://grafomatic01.twoday.net/stories/4839779/
> 
> I found this to work really smoothly, and as you can
> see, the final image doesn't contain any color "spill"
> at the edges of the object.
> 
> HTH,
> 
> Claus
> 


-- 
Claus Cyrny : Webdesign |  Grafik | Fotografie
:: Web: http://home.arcor.de/ccyrny/ ::.