How to improve this one?

redice

I tried to solve this captcha(http://gsxt.hnaic.gov.cn/VerifierImage.jpg) with following filters, but the result is bad. The accuracy is less than 5%.

-scale 200%

-threshold 50%

-remove-dust 2

-remove-objects 30

-segment 50

How to improve it? Thanks a lot.

Sven

got a 50% success rate with just the Max / min filters...will add that on next release. Can probably improve success rate much further.