Tag Archives: John Graham-Cumming

Fake Photos-A Thing of the Past?

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image from WSJ.com

You may have already heard about the Chinese antelope that weren’t: This, from WSJ’s Jane Spencer and Juliet Ye:

Earlier this week, Xinhua, China’s state-run news agency, issued an unusual public apology for publishing a doctored photograph of Tibetan wildlife frolicking near a high-speed train.

The deception — uncovered by Chinese Internet users who sniffed out a Photoshop scam in the award-winning picture — has brought on a big debate about media ethics, China’s troubled relationship with Tibet, and how pregnant antelope react to noise.

The photographer and editor involved have since resigned. But this took two years to out; you look at the photo now and you just know that it’s not real. And this, of course, is not the first time photos have been doctored by news organisations that should know better (there’s Reutersgate, as it’s sometimes called, when Lebanese freelance photographer Adnan Hajj was caught allegedly duplicating flares, buildings and plumes of smoke for Reuters. More on photoshopping at Wikipedia). How can we avoid this?

One option is to be a bit more discerning about the pictures we see, whatever their provenance. Another is to turn to technology. Academics Jessica Fridrich, David Soukal and Jan Lukáš looked at

detection of a special type of digital forgery – the copy-move attack in which a part of the image is copied and pasted somewhere else in the image with the intent to cover an important image feature.

Their paper [PDF] investigated the problem of detecting the copy-move forgery and described what they called “an efficient and reliable detection method”. John Graham-Cumming, best known for his work on Bayesian spam filters, made it a reality with an algorithm that implements automatic detection of image alteration using copy/paste. (OK, he did it because he wanted to win money in a spot the ball competition, but it’s still good work.)

A guy called John Wiseman has made a few modifications to the code so it works faster, and has shown how it works well in detecting the alterations in Adnan’s photos:

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The blue and red bits are where there are duplicated pixels. The code didn’t work very well on the Chinese antelope picture because that involves splicing two pictures together more than copy/move. But it’s worth a look.

Is this going to bring to an end Photoshopping? Probably not. But it might make us more skeptical, and if tools like this are readily available, more likely to run suspect photos through the wringer until we’re sure that what we see actually happened like that.

China Eats Crow Over Faked Photo Of Rare Antelope – WSJ.com

A New Image for Your Email Address

John Graham-Cumming, author of Bayesian spam filter POPFile, points me to a neat tool he’s created which will turn an email address into an image that may spare you some spam from bots scouring web pages for email addresses:

This site converts a text-based email address (such as me@example.com) and creates an image that can be inserted on a web site. The image contains the email address and is easily read by a human, but is intended to fool web crawlers that search for email addresses.

I can’t guarantee that this is foolproof, but Project Honeypot reports that image obfuscation of an email address is very effective (they say 100%) against web crawlers.

Enter your email address in the box and the server returns a string of gobbledygook which contains the email address (padded with a large amount of random data to avoid a dictionary attack) encrypted using a key known only to the server. When the image is loaded into the web page the server decrypts the email address and creates the image. (The email address is not stored by the server; it resides only in the HTML on your website.)

 Here’s what mine looks like:


Made using jeaig

If you need to put a contact address on your webpage or blog, but hate the amount of spam you’re getting, it’s worth a try.

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Put My Book in Your Toilet

John Graham-Cumming, the father of the excellent Bayesian spam killer POPFile, has written a review of my column collection, Loose Wire. It’s a fun read (the review, not the book, although the book is. Really.) He even adds a word to my lexicon:

‘wagstaff (v): to poke any new technology with a long stick, make sure it does what it says on the box, and summarize the experience in less than 2,000 words’.

John concludes that the book “should be in the toilet. In fact, I think it’s such a good book for reading in small doses in a small, quiet room, that a global band of Gideons-like technology evangelists should be leaving copies in the smallest room in the house of any technophile.” Excellent idea. I’ll get onto my publisher about that.

Note: Getting Your Head Around Spam

 This is not new, but worth passing on to those folk that would like to understand spam a bit better. Spam is a pain for all of us, and it’s not likely to get better. But the more we understand it, the more we can do something about it. If you think it’s just a bunch of sleazy guys who don’t know about computers and don’t know how much damage they cause, read this. It’s a PDF Acrobat file version of the presentation by one John Graham-Cumming, who designed the free POPFile spam filter I use and rave about every chance I get.
 
 
John goes into fascinating detail about the tricks spammers use, which helps us realise a couple of things:
 
1) These spammers are smart, or have smart people working for them;
2) Spamming is not going to go away, and spam filters are going to have to get smarter to keep up;
3) It may be worth splashing out on spam filter software if you’re a big company, but if you’re an individual, you may well be better off using POPFile and doing what you can to support folk like John, who are as close to the cutting edge of anti-spam design as anyone. (If you really like his work, buy some of his stuff.)