New CAPTCHA

[MKruer]

I don’t think that would work by it self. If you adjust the luminance you can easily read the image. On top of that a bot would be able to easily distinguish between red and green dots, probably more so then humans, however if you change the color through the image then it might work better but be much more difficult to read.

[robertmf]

Well, you 3 are a "small sample". The numbers say when 12-13 people look at the [7], then 1 of them will not be able to see the "7".

What I really should have done for a better control is put up the [7] and ask who sees a [4] !!! LOLOOL ... not that anyone here would lie ........... PP

Color vision online test :
http://colorvisiontesting.com/online%20 ... Number%201" target="_blank

How color-challenged view the world :
http://colorvisiontesting.com/what%20co ... %20see.htm" target="_blank

I knew the "what it is" but until now not the term "captcha". Getting it correct for optically challenged people seems difficult; since color blindness comes in several degrees of severeness

... so perhaps best to lay off colors and keep things black and white ? ...

... Although colorvisiontesting.com claims [attachment] colors combo should be seen by all.

[ElbertF]

A few examples of my CAPTCHA.. Using several fonts and rotations, characters never look the same.

3.jpg (19.31 KiB) Viewed 7214 times

613E7

2.jpg (19.4 KiB) Viewed 7223 times

2A7A8

1.jpg (21.18 KiB) Viewed 7216 times

8BF0

[EXreaction]

A few examples of my CAPTCHA.. Using several fonts and rotations, characters never look the same.

Looks pretty good...but that 1 in the second one really looks like a 7.

[LEW21]

On the 1st image last number is more like 7 than 1.

EDIT: EXreaction was first

[ElbertF]

Yeah it's not perfect yet.. All 7's should probably be dashed for more clarity.

The letters look a little 3D-ish, I think a computer will have a hard time reading it since the front color is the same as the background (well almost). It still obvious or humans (the "2" in the second picture for example).

[DavidMJ]

In the world of OCR, almost never counts. Sharp changes in color make it very easy for an edge detection to occur.

[ElbertF]

Edge detection is no good if you can't extract relevant information from the rest. Especially the A's here become even less readable, although the 8 is a give away

download.gif (23.58 KiB) Viewed 7411 times

I'd like to work with blur, I know there is a function for it but it's not working with my PHP-version..

[robertmf]

A few examples of my CAPTCHA.. Using several fonts and rotations, characters never look the same.

Looks pretty good...but that 1 in the second one really looks like a 7.

It **is** a [7] !!!

I do prefer these latter pastels.

[NeoThermic]

Edge detection is no good if you can't extract relevant information from the rest.

Edge detection is but a tool in the toolkit for breaking captcha's. Also, I'm not sure why you made the result black and white. Decent edge detection doesn't need to make things black/white to work. You can overlay the edge detection to the coloured image and work from that (since you now have a diffrent colour on the "inside" of the letter (and yes, you can work out what "inside" is from this method).

Here's a quick 7 line example I whipped up. Also notice how it is rather sensitive (it picked up on the JPG compression...)

Edge detection in 7 lines

namloos.png (16.19 KiB) Viewed 7478 times

(click it to see the correct size, as the resized image is expanded)

If you throw in a milti-coloured background, and possibly do the same for the letters, you might have something decent enough, but I do have to ask what is the CPU cost of one of these images?

NeoThermic