A team of MIT scientists, led by Prof. Adelson and Dr. Johnson, have created an incredibly cool device for making extremely detailed and rapid surface measurements. Althought this is outside of the scope of image forensics, it does have some interesting applications to fingerprint and firearm forensics.
Welcome to the Fourandsix blog, where you’ll find tips on image forensics techniques and commentary on issues relevant to photo tampering and the responsible use of imaging tools.
I’ve always thought that one of the best features of a legal system is the notion that a person is innocent until proven guilty. In such a system, a defendant in a criminal trial does not have to prove their innocence. Rather, the prosecution must prove guilt beyond a reasonable doubt.1 I would argue that photo forensic analysts should employ similar standards. We should start with the assumption that a photo is authentic and only conclude that it is fake when the preponderance of evidence excludes any other reasonable conclusion.
For a while, I was publishing a semi-regular feature in this blog entitled “Truthful Photo Editing,” in which I described how best to approach the editing features in tools like Photoshop so as to maintain the original truth of a photo. One of the recurring themes of those posts is that there are, unfortunately, few firm rules about what tools and techniques are acceptable in a truthful workflow. Almost any tool can be used both sparingly in ways that enhance and severely in ways that distort, and what level of truth must be maintained is dependent on context. The type of editing permissible in photojournalism differs from what is permissible in a legal setting or in a medical image. Ultimately there is no substitute for good judgment. But applying good judgment is hard, especially when the baseline of truth you’re comparing against is itself open to interpretation.
This week, a controversy regarding this year’s winner of the World Press Photo contest came to a head. Since the contest winner was announced earlier this year, there have been concerns that the photo looked a little too unreal and even cinematic to be an authentic photo. Those concerns reached a new level this week when the Hacker Factor blog posted evidence which it claimed showed that the award-winning photo was in fact a composite of multiple images. After this claim blew up further on the Extreme Tech website, Fourandsix was enlisted by World Press Photo to help settle the issue. We provided our own analysis refuting the other evidence, and demonstrating that the photo is not a composite but rather a single photo to which adjustments have been applied to selective regions.
I was recently talking to my friend and colleague Prof. Michael Black about a seemingly unlikely image of President Obama and Vice President Biden putting on the White House lawn. We were discussing how a shadow and lighting analysis could be applied to this image to determine if it is fake. Michael made the clever observation that the President’s left ear provides further information about the lighting in the scene.