Kelly Jones wrote:
> Spammers are starting to put "speckles" in their images to defeat
> OCR-scanning plugins such as FuzzyOCR.
That's a very old technique.
> I thought ImageMagick's -despeckle option would help, but it doesn't
> seem to, not even when applied multiple times, not even in conjunction
> with -monochrome.
Have you tried a simple `gocr -d 4 ...` it does a good job with those images.
> I want a filter that does this for each pixel X:
man gocr:
...
-d size
set dust size in pixels (clusters smaller than this are
removed), 0 means no clusters are removed, the default is -1 for
auto detection
...
> 1) if any of X's 8 neighbor pixels is the same color, turn X black
> 2) otherwise, turn X white
>
> Can some combination of options to convert do this?
>
> I realize that:
>
> 1. This will only work w/ indexed-color images (eg, GIFs) and not JPEGs,
> etc.
> 2. Spammers will soon work around this, so this is just a short-term
> bandage.
> 3. I could write something in libgd to do this (blech!)
Whatever.
--
René Berber
