Identifying manipulated images

Photo-editing software gets more sophisticated all the time, allowing users to alter pictures in ways both fun and fraudulent. Automatic data backup software Last month, for example, a photo of Tibetan antelope roaming alongside a high-speed train was revealed to be a fake, according to the Wall Street Journal, after having been published by China’s state-run news agency. Backup software for pc Researchers are working on a variety of digital forensics tools, including those that analyze the lighting in an image, in hopes of making it easier to catch such manipulations.


External hard drive backup software free True or false? The tool used above spots whether an image has been manipulated by modeling the lighting in the image based on an analysis of visible surfaces. Open source backup software To analyze an image, a user indicates the surfaces to consider using contour lines (shown above in white). Driver backup and restore software The system checks for inconsistencies in the way that those surfaces are lit.

Tools that analyze lighting are particularly useful because “lighting is hard to fake” without leaving a trace, says Micah Kimo Johnson, a researcher in the brain- and cognitive-sciences department at MIT, whose work includes designing tools for digital forensics. Tape backup software As a result, even frauds that look good to the naked eye are likely to contain inconsistencies that can be picked up by software.

Many fraudulent images are created by combining parts of two or more photographs into a single image. Driver backup software free download for windows 7 When the parts are combined, the combination can sometimes be spotted by variations in the lighting conditions within the image. Automatic data backup software free download An observant person might notice such variations, Johnson says; however, “people are pretty insensitive to lighting.” Software tools are useful, he says, because they can help quantify lighting irregularities–they can give solid information during evaluations of images submitted as evidence in court, for example–and because they can analyze more complicated lighting conditions than the human eye can. Best backup recovery software Johnson notes that in many indoor environments, there are dozens of light sources, including lightbulbs and windows. Pc software backup Each light source contributes to the complexity of the overall lighting in the image.

Johnson’s tool, which requires an expert user, works by modeling the lighting in the image based on clues garnered from various surfaces within the image. Software free backup (It works best for images that contain surfaces of a fairly uniform color.) The user indicates the surface he wants to consider, and the program returns a set of coefficients to a complex equation that represents the surrounding lighting environment as a whole. Best backup software for servers That set of numbers can then be compared with results from other surfaces in the image. Backup schedule software If the results fall outside a certain variance, the user can flag the image as possibly manipulated.

Hany Farid, a professor of computer science at Dartmouth College, who collaborated with Johnson in designing the tool and is a leader in the field of digital forensics, says that “for tampering, there’s no silver button.” Different manipulations will be spotted by different tools, he points out. Beste backup software As a result, Farid says, there’s a need for a variety of tools that can help experts detect manipulated images and can give a solid rationale for why those images have been flagged.

Neal Krawetz, who owns a computer consulting firm called Hacker Factor, presented his own image-analysis tools last month at the Black Hat 2008 conference in Washington, DC. Free server backup software Among his tools was one that looks for the light direction in an image. Best backup image software The tool focuses on an individual pixel and finds the lightest of the surrounding pixels. Xp backup software It assumes that light is coming from that direction, and it processes the image according to that assumption, color-coding it based on light sources. Data backup and recovery software While the results are noisy, Krawetz says, they can be used to spot disparities in lighting. Software untuk backup driver He says that his tool, which has not been peer-reviewed, is meant as an aid for average people who want to consider whether an image has been manipulated–for example, people curious about content that they find online.

Cynthia Baron, associate director of digital media programs at Northeastern University and author of a book on digital forensics, is familiar with both Krawetz’s and Farid’s work. Best pc backup software She says that digital forensics is a new enough field of research that even the best tools are still some distance away from being helpful to a general user. Apps backup software In the meantime, she says, “it helps to be on the alert.” Baron notes that, while sophisticated users could make fraudulent images that would evade detection by the available tools, many manipulations aren’t very sophisticated. Continuous backup software “It’s amazing to me, some of the things that make their way onto the Web and that people believe are real,” she says. Free backup software for external hard drive “Many of the things that software can point out, you can see with the naked eye, but you don’t notice it.”

Johnson says that he sees a need for tools that a news agency, for example, could use to quickly perform a dozen basic checks on an image to look for fraud. Auto backup software windows 7 While it might not catch all tampering, he says, such a tool would be an important step, and it could work “like an initial spam filter.” As part of developing that type of tool, he says, work needs to be done on creating better interfaces for existing tools that would make them accessible to a general audience.

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