The latest issue of Scientific American (June’s), has an article on techniques used to detect when digital images have been manipulated. Here’s an extract:
[quote author=“Scientific American”]History is riddled with the remnants of photographic tampering. Stalin, Mao, Hitler, Mussolini, Castro and Brezhnev each had photographs manipulated—from creating more heroic-looking poses to erasing enemies or bottles of beer. In Stalin’s day, such phony images required long hours of cumbersome work in a darkroom, but today anyone with a computer can readily produce fakes that can be very hard to detect.
Barely a month goes by without some newly uncovered fraudulent image making it into the news. In February, for instance, an award-winning photograph depicting a herd of endangered Tibetan antelope apparently undisturbed by a new high-speed train racing nearby was uncovered to be a fake. The photograph had appeared in hundreds of newspapers in China after the controversial train line was opened with much patriotic fanfare in mid-2006. A few people had noticed oddities immediately, such as how some of the antelope were pregnant, but there were no young, as should have been the case at the time of year the train began running. Doubts finally became public when the picture was featured in the Beijing subway this year and other flaws came to light, such as a join line where two images had been stitched together.
[...]
The validity of an image can determine whether or not someone goes to prison and whether a claimed scientific discovery is a revolutionary advance or a craven deception that will leave a dark stain on the entire field. Fake images can sway elections, as is thought to have happened with the electoral defeat of Senator Millard E. Tydings in 1950, after a doctored picture was released showing him talking with Earl Browder, the leader of the American Communist Party.
Political ads in recent years have seen a startling number of doctored photographs, such as a faux newspaper clipping distributed on the Internet in early 2004 that purported to show John Kerry on stage with Jane Fonda at a 1970s Vietnam War protest. More than ever before, it is important to know when seeing can be believing.
The author, Henry Farid, has a website here.
