On 6/11/07, Robert Cummings <robert@xxxxxxxxxxxxx> wrote:
On Mon, 2007-06-11 at 14:29 -0400, Daniel Brown wrote: > > > To be a bit easier, I whipped up a quick example on the web. It's > > > just static images, not a working system, but you'll see what we're > > > getting at here: > > > http://pilotpig.net/captcha-example.php > > > > > > > You could even use a color check here to see which color matches the best ;) > > > > Ah, but that validates my exact point --- the system will see the > overlay over the legitimate cigarette image as being image-synonymous > with the snake as an option by color pattern, while the parent image > matches best with the first child option image in shape. Not as easy as Tijnema thinks... all the icons are in a single image so first he needs to find the icon boundaries to extract them to perform colour analysis. And that can be more or less hard depending on how the icons are merged. For instance using PNG images with alpha transparency so that an overlay and merge looks right would make edge detection of the icon difficult ths making colour analysis difficult.
Sure, but what if I convert the image first to JPEG or GIF? GIF would be the easiest option I think, because if I convert both then I could easily count the color of each pixel and you can call the job done. :)
Also, the colour analysis only works in the case where you're presented with an image and asked to pick the same image form the set. It doesn't work in the semantic example where you are asked "which of the following doesn't belong?" :)
Of course, it was just an easy example, as there could be images presented with exactly the same color. Different CAPTCHA program needs different kind of hack... Tijnema -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
