Photographers have been manipulating images ever since Abraham Lincoln’s head was attached to John C. Calhoun’s body in one of Lincoln’s most famous portraits. But today, digital technology has made tampering easier and more pervasive than ever. Some believe the trend threatens the public’s fundamental faith in the practice of photojournalism.
In this context, Dr. Hany Farid should be a hero to photojournalists and lovers of photojournalism. Farid, who runs the Image Science Group at Dartmouth College, has emerged as a leading authority on digital forensics. His team has developed some of the most advanced software currently available to detect photo manipulation.
While media organizations — increasingly rocked by photo-doctoring scandals — have not yet invested in Farid’s technology, it seems only a matter of time before this occurs. Here’s our Q&A with Farid:
Q: Tell us a little about the Image Science Group and its origins.
A: The Image Science Group is my research group at Dartmouth College, and was founded when I came to Dartmouth in 1999. The group typically consists of 3-4 graduate students, a few undergraduates and a programmer. Since its inception, we have focused on various research topics in image analysis, computer vision, medical imaging, and human perception. For the past five years, we have focused almost exclusively on digital forensics.
Q: How do you define “digital forensics” as it applies to photography? Why is it important?
A: In the field of digital forensics, we develop computational and mathematical techniques to detect tampering in digital images (and audio/video). Recent advances in this field operate in the absence of digital watermarks or signatures and hence require no specially equipped cameras. Advances in digital cameras and software have made it easier to manipulate digital images. As a result, we are beginning to lose faith in photography. As such, I believe that it is important to develop techniques to authenticate digital images.
Q: Most photojournalists are familiar with the ethical issue of photo manipulation in journalism. In what other fields has the issue arisen as a concern?
A: We are seeing the impact of digital manipulation in the media, courts, science, politics and business. The courts in particular are struggling with this issue. Our work in digital forensics has been used in many legal cases where digital images or video are introduced as evidence. From criminal cases to civil cases to medical malpractice cases, digital recordings are frequently introduced into a court of law as evidence. And, the specter of digital tampering is being raised to counter such evidence.
Q: Tell us about the algorithm-based tools you’ve developed — and are developing — to help identify altered images.
A: We have developed many different tools to detect tampering. One tool detects cloning (copy/paste), another detects inconsistencies in lighting, another detects inconsistencies in optical aberrations, and there are many more. Our general philosophy has been to develop a large suite of tools, each of which detects a different form of tampering. Combined, these tools will make it harder to create convincing forgeries (but, of course, never impossible).
Q: Are any journalistic organizations using these tools currently?
A: There are no media outlets using these tools right now, but I expect that they will as we further refine and expand on our work.
Q: What do your tools do that a savvy editor scrutinizing an image in Photoshop can’t do on his or her own?
A: While a good photo editor can spot certain types of fakes, there are many subtle statistical and geometric inconsistencies that are effectively impossible to spot with the naked eye. And, as photo-editing software improves, it will become increasingly more difficult to detect fakes.
Q: How are you working with companies like Microsoft and Adobe?
A: Both Adobe and Microsoft partially fund our group. Both companies believe that it is important to support academic research, and believe that digital tampering is an important problem that needs to be addressed on the technical, legal, and ethical level.
Q: What advances do you expect to see in digital forensics over the next three to five years? Will the violators always be able to stay a step ahead — or do you think the pervasiveness of improper digital alteration can be reduced over the long term?
A: We continue to develop digital forensic tools to detect tampering in audio, image and video. A particularly exciting new frontier is in digital ballistics — that of linking an image with a specific camera (similar to handgun ballistics). Tampering and forensics is similar to spam/anti-spam and virus/anti-virus. It will always be easier to create forgeries than it will be to detect them. I predict, however, that we will take the ability to create convincing forgeries out of the hands of the average user, and make it more difficult and time consuming for the expert to create a fake that cannot be detected.
[tags]dartmouth, digital photography, digital forensics, doctored photos, Photoshop, digital manipulation[/tags]