What's up, bot? Google tries new Captcha method
Which way is up? Google's test relies on finding images that are easy for people but hard for computers to orient correctly.
(Credit: Google)Google has released research results about a new test to foil computers pretending to be humans by requiring them to orient an image so it's upright.
A persistent problem on the Internet is screening out automated computer systems that can be used, for example, to sign up for spam-sending e-mail accounts or post comments designed to improve a site's search results. Google, which already devotes a lot of resources to block e-mail and Web spam, has tried a new test to keep the bots at bay.
The test is the latest variation on a screening technique called a Captcha (completely automated public Turing test to tell computers and humans apart). The idea is that people can often tell which way is up in a photo, but computers have a harder time.
Captchas are in widespread use today, usually in the form of obscured or distorted text that people can still read. But there's a lot of work in the area, including identifying 3D images and distinguishing between cats and dogs.
Here's how Google authors Rich Gossweiler, Maryam Kamvar, and Shumeet Baluja described the image-orientation technique in their paper (click for PDF):
This task requires analysis of the often complex contents of an image, a task which humans usually perform well and machines generally do not.
Given a large repository of images, such as those from a web search result, we use a suite of automated orientation detectors to prune those images that can be automatically set upright easily. We then apply a social feedback mechanism to verify that the remaining images have a human-recognizable upright orientation.
The main advantages of our Captcha technique over the traditional text recognition techniques are that it is language-independent, does not require text-entry (e.g. for a mobile device), and employs another domain for Captcha generation beyond character obfuscation. This Captcha lends itself to rapid implementation and has an almost limitless supply of images.
We conducted extensive experiments to measure the viability of this technique...Our Captcha technique achieves high success rates for humans and low success rates for bots, does not require text entry, and is more enjoyable for the user than text-based Captcha.
Images can be hard for people to orient upright, too. One 500-person test showed wide disparities in the opinion of which way was up for the left image but not the right image.
(Credit: Google)The tricky part is finding the right balance between too easy and too confusing. Some images are hard for people to orient correctly, and some have cues--faces, text, blue skies, and green grass--that computers can use to figure out which way is up.
To get around this issue, while being able to draw from the large number of images on the Web, the technique presents people with new images as well as those known to perform well. If people have trouble consistently telling which way is up, that image isn't included in the library.
The researchers like their system in part because the image doesn't have to be obscured or distorted, as in text-based Captchas such as those Google currently employs. But image-based Captchas aren't immune from the bot vs. Web site arms race.
"As advances are made in orientation detection systems, these advances will be incorporated in our filters so that those images that can be automatically oriented are not presented to the user," the researchers said. "The use of distortions may eventually be required."
Stephen Shankland writes about a wide range of technology and products, but has a particular focus on browsers and digital photography. He joined CNET News in 1998 and since then also has covered Google, Yahoo, servers, supercomputing, Linux and open-source software, and science. E-mail Stephen, or follow him on Twitter at http://www.twitter.com/stshank. 
This kind of captcha research wasn't intended to serve blind people. It was intended to serve the interests of people who might use it to protect their resources that DON'T CATER TO BLIND PEOPLE. It was done to THWART AUTOMATED BOTS THAT HAVE FIGURED OUT CAPTCHA!
Do I sound mean? Yes. Does this smack of common sense? ABSOLUTELY! Want me to slap you with some?
The challenge would be to have enough questions with enough answers to make it impractical to have a bot net try all of the answers.
I have less than perfect sight, though I'm not blind (perhaps the Internet was half-designed for me but will serve me less and less over time?).
"It was intended to serve the interests of people who might use it to protect their resources that DON'T CATER TO BLIND PEOPLE"
That's bollocks, WarpKat. Captchas are used to "protect" many things that blind and hard-of-sight people use a lot - email systems, blog and commenting systems, account registrations. But then, we should probably just go back and get some help from those who can actually see rather than trying to be independent. Yeah OK.
"Do I sound mean?" No, you sound like a... never mind.
"Does this smack of common sense?"
No, it's lazy. Work on identifying and eliminating spam and spammers rather than hurting legitimate users. The fact that CAPTCHA has to evolve because it can be cracked automatically (or, at least, spammers are using humans to solve them) means that the system isn't working.
"Want me to slap you with some?"
Some what? Try using complete sentences and you might make sense.
Same for you Nashville2.
People who automatically just push a button, or who just like to type "Accessibility," or who don't read the article / directions will probably fail.
This is an improvement on the image distortion of text test. You might as well say "What about people who don't know how to use a mouse?" This is not the end-all-be-all of test scenarios.
If you only use a text / screen reader, then going through lots of spam is very time consuming and very annoying. This will reduce the amount of spam that you get.
Really, the BEST captcha...... a valid e-mail address. There should be a requirement on ALL these systems that you have to sign up for them, and that you HAVE TO VALIDATE WITH A LINK IN AN E-MAIL SENT TO YOU!
That is what most of the internet forums I look at do: CAPTCHA AND a validation e-mail before you can post.
I remember using file2hd.com once last year, they had a terrible captcha. It took my ~30 tries to get it because it was so distorted that the letters were beyond recognition. At least they took images from a pool of around 20 or so(they didn't generate them!) which meant I had a second chance at some. Still gives me nightmares :P
Lets ban colors to its unfair that blind people can't enjoy them and games as well.
There is no way around using some sort of a test to see if you are a human or not. Another proposal is to require users to pay real money to submit forms, but that isn't as palatable as CAPTCHA.
Yes!! To sign up for an email address you must first have an email address! It's genius!
On a serious note, if you're blind, ask for some human assistance.
FYI
The Web is not accessible. Sorry.
"...It is important to note that computer-vision techniques have not yet been successful at unconstrained object detection; therefore, it is infeasible to recognize the vast majority of objects in typical images and use the knowledge of the object?s shape to orient the image."
Fundamentally I think the limitation in the technique is that... there is no real limitation for object detection. Google itself if I recall already has a primitive tool for doing this, and it is only a matter of time, not machine intelligence, before it becomes accurate enough for this purpose. A true CAPTCHA has to rely on some inherent machine-human limitation that cant' be rectified by brute force. Spoken language, for example, is much tougher because a machine must imitate a human by splicing words/phonemes to articulate sentences. The key distinction now is, no matter how good the machine gets at such imitation, another machine can be trained to detect these splices. Sort of like using a thief to catch a thief.
I think the real problem will be the occasional porn that may slip through. :)
At least Google is testing this and evaluating it to improve it.
And there are people who have vision problems, but are not blind. Let's keep them in mind, too.
The problem with face recognition is not everyone owns a webcam and some won't support the face recognition.
Even with image recognition, unless the bot/computer software has a way to compare the orginal image as a reference, I doubt it would be capable of determining depth perception.
As long as there is a valid alternative for users with vision loss to get through the captcha code entry, as far as I'm concerned anything that makes it harder for spammers to spew their garbage online is a good thing.
For the people who think their snide comments regarding blind/low-vision users are funny... not all my blind friends were born blind. If, God forbid, you suffer vision loss later in life, let me know how funny you think your comments are then.
In the words of Tom Raftery, captchas are lame because "1. they force the burden of work back on your [user]r and pushing extra work on your [users] displays a lack of respect;" and "2. they show you are too lazy to properly secure your [site] against [attacks]" using other methods.
It uses things like biometrics Finger Face and Voice verification, and even a special biometric smart card. It also has other methods as well. The face verification uses a standard web cam. So seems to be better than just entering random so the site can actually verify it is the valid user.
A site can easily implement this, and once a user has installed it at their end, they can verify to any web site that has implemented it.
It is highly secure and simple to use and can be for registering, logging on, even payment approval.
Worth taking a look.
coocurrence in a small context is really hard for a computer to deal with.
However I do not think the problem with this one is its accessibility but how easy it will be to crack it. The problem is not how easy it will be for a bot to crack the image but the small size of the answer set. The user will have given a valid answer if it is orientated a few degrees either side of what is considered the correct orientation. This means that there are only 20-30 correct answers, a bot will happily keep trying and a one in thirty hit rate guaranteed with little processing power required is really no protection.
Putting my accessibility hat on again. Accessibility is not just about people with vision impairments but about people with other disabilities including disabilities that limit the use of the mouse or keyboard. Question how would someone who used voice recognition respond.
- by bubazoo April 21, 2009 10:10 AM PDT
- another problem with captcha's, most of the time even SIGHTED people have problems seeing them!!! You don't know how many times I've been on a site and haven't been able to see a captcha, so I turn and ask like 12 different people, and there not able to see it either!!! It isn't just the blind that has problems seeing captcha's folks... I mean, not everybody has teenager eagle eyes....its just that people don't care about anyone but themselves, they look out for #1 and thats it, thats the whole problem with this world, nobody cares about anyone but themselves.
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(47 Comments)I personally like the idea that discussion forums have used for years. I mean common, who doesn't have an email address?!! Let me put it this way, who DOESN'T have an email address!! I mean common my 12 year old nephew has an email address, don't give me that. I've got probably 50 of 'em at least I'm sure. lol forums even go a step further by not accepting email addresses from places like yahoo, hotmail, etc. thats a good idea, because a spammer can break into yahoo or hotmail quite easily, so to accept a verizon or comcast or aol address is a very good idea, that way you know the person is legit...and like I said, even my 8 year old nephew has an aol email address. I mean common. lol kids even have email in grade school now.