Maptcha: An Experiment in Map-Based CAPTCHA
maptcha.com
Maptcha: An Experiment in Map-Based CAPTCHA
1–10 of 31 posts
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#2I like how you are thinking outside the box a bit.
Having said that, there are a couple of issues: 1) This is really not a hard problem for a computer to solve. Detecting different image types is pretty trivial. You made it a lot easier by making the letters sit in the boxes in a regular manner. 2) A high percentage of captchas are now broken by humans, instead of robots. This is not a problem you will likely encounter in a small site, though.
(1) Is an easier problem to solve. You could do "input the letters near the cat", or "input the letters near the map of florida".
(2) Is harder, but most of the people who break captchas live in 3rd world countries, so you could possibly arbitrage cultural knowledge (see florida example above). They will catch on pretty damn quick, though.
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#3The first example is not indicative of the actual difficulty because the letters are pink (this is noted, but still).
Beyond that, the examples use extremely hard to see letters... that completely defeats the purpose. There's no need if the challenging part for the computer is detecting satellite imagery.
There are multiple letters on some of the images, sometimes hovering between two images. Again, why? The computer is going to have no problem divvying up the images, but the ambiguity is confusing for humans.
Make the letters as easy to read as possible please. If that breaks your captcha, find a new captcha method.
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#4Great idea but I don't think it's the solution to the captcha problem. There's a lot of visual noise for a person to analyse and I found it considerably harder than reCaptcha types. However that may be a bonus for deterring human solved captcha à la deathbycaptcha.com
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#5It's not very quick or readable, and it's not useful for users with impaired vision.
Technically it has two weaknesses:
- non-map images are chosen from a small set. Good implementation will need equally large set of non-map (and presumably non-offensive and deceptively map-like) images.
- satellite photos don't seem very hard to identify, e.g. even using histogram as an input to a simple classification algorithm could give decent accuracy (gray/brown/dark green color scheme dominates) and tree shadows, cars and rooftops may be easy features to detect with fancier algorithms.
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#6I was expecting "click on Tennessee" and then a region of the US - which might actually be an appropriate captcha if you assume the site users know US state geography.
This however, is difficult to read for a human and probably easy to write a bot for.
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#7No images are displayed in Firefox. I just see the pink letters.
Works fine in Chrome.
IE just shows nothing except a black bar on the left.
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#8one thing i found very irritating: in one of the tests that asked to type the group of letters where the image is from satellite, i find the group "y p k a 1" but the answer i got was 'wrong, group is "k p y a 1"'. if i am not mistaken, based on the mathematical definition of the group, groups "y p k a 1" and "k p y a 1" are the same
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#9This should be accompanied by an image classifier to demonstrate its effectiveness.
My guess is the contiguous nature of the satellite images might make the problem a bit easier, sort of like Battleship.
Re: Maptcha: An Experiment in Map-Based CAPTCHA
#10Apparently street view cars are also considered as satellite photos.