[Mimedefang] Image validator/OCR SA plugin

[Martin Blapp]

> Interesting... What's the performance like with this? How many messages
> do you scan per day with it?

It is rather fast. On a Pentium IV 3Ghz I can scan a average jpg/gif picture in
0,2 - 0,3 seconds.

I've limited the scantime to 5 seconds per image, and I allow only three images 
to be scanned per mail. Of course this is user configurable.

The greps here are just up to now, not a full day.

grep hits= /var/log/maillog | wc -l
    78050

grep "X-Spam-Status: Yes" /var/log/maillog | wc -l
    48400

grep hits=.*SPAMPIC /var/log/maillog | wc -l
     9572

grep "X-Spam-Status: Yes.*hits=.*SPAMPIC" /var/log/maillog | wc -l
     9558

grep "X-Spam-Status: Yes.*hits=.*SPAMPIC" /var/log/maillog | grep HTML_IMAGE_ONLY | wc -l
     9528

# grep HTML_IMAGE_ONLY /var/log/maillog | wc -l
    35834

This means 60% of all mails we get are SPAM. More than 10% of the SPAM
are some gif and jpg pictures advertizing for stocks and meds.

But almost 45% of all mails match HTML_IMAGE_ONLY, so it's unusable
at all. I even use lower scores for those rules now - which gives
me less FPS:

score HTML_IMAGE_ONLY_04        1.400
score HTML_IMAGE_ONLY_08        1.300
score HTML_IMAGE_ONLY_12        1.200
score HTML_IMAGE_ONLY_16        1.100
score HTML_IMAGE_ONLY_20        0.950
score HTML_IMAGE_ONLY_24        0.900
score HTML_IMAGE_ONLY_28        0.700
score HTML_IMAGE_ONLY_32        0.400

Martin