On 6/11/07, Tijnema <tijnema@xxxxxxxxx> wrote:
On 6/11/07, Robert Cummings <robert@xxxxxxxxxxxxx> wrote: > On Mon, 2007-06-11 at 10:38 -0400, tedd wrote: > > Gnag: > > > > I know we can beat this thing to death, as we have in previous > > threads and I don't anyone wants to travel previously traveled ground. > > > > However, Rob said: > > > > "A good captcha will try to exploit a computer's weaknesses." > > > > So, let's expound on that -- what do you consider to be a computer's weakness? > > Well for instance as humans we can fairly easily recognize similar > shapes. We can recognize an apple whether it is red, green, yellow, has > a stem, has a leaf, is half eaten. A computer might recognize a circle, > and might guess that the circle is an apple based on further analysis. > But we as humans could recognize it as an apple even if we stretched it > a bit so it was no longer circular, or as I said, if it was a crescent > because someone had taken a huge bite out of it. This is something > humans excel at... inferring information from similar previous > experiences. > > Taking the image captcha to a different level, one could combine our > ability to understand language as well as imagery. For instance we could > have an icon repository of animals, vehicles, plants, etc (very obvious > ones anyways). Then to create a captcha we could randomly select X > icons, slightly morph them to spoof matching them within the captcha > image itself, then ask: > > What animal do you see in the above picture? > > I think someone already said microsoft or someone does something > similar. The principle is that we know what generally constitutes an > animal and a computer does not. Similarly, an audio complement would be > to have a background sound of maybe low level radio chatter overlaid > with the sounds of various everyday items... then one could ask: > > What did you hear ringing? > > Possible answers... a bell, the telephone, an alarm, etc. > > The problem then becomes an issue of people who can't spell or are > terrible at recognizing everyday things. > > Cheers, > Rob. Server builds up a database of pictures, client does the same with MD5 check, and problem solved...:) Tijnema -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
We're not talking about simply masking of the name of pictures (apple.jpg, car.jpg, fat_slut.jpg, bench.jpg, etc.), but rather morphing those images a bit. They'd still be recognized if skewed, noise is added, and so on, but not as readily to a computer as a human being (unless, perhaps, it's something like Robonova - http://www.robots-dreams.com/2007/05/robot_image_rec.html). -- Daniel P. Brown [office] (570-) 587-7080 Ext. 272 [mobile] (570-) 766-8107 -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
