Thursday, October 15, 2009

Video: Exposing Digital Forgeries from Inconsistencies in Lighting

I found this video from a conference on photo forensics, through DGrin.  It is a rather long (one hour) but very good presentation by Prof Hany Farid of Dartmouth, from 2007.

We all do computer post-processing in our digital photos to some extent, be it cropping for composition, improving light and contrast, or removing unwanted objects or subjects as too distracting. All of this is ok as photography is art, unless you do photojournalism; then you can get in trouble.

From their site:


With the advent of high-resolution digital cameras, powerful personal computers and sophisticated photo-editing software, the manipulation of digital images is becoming more common. To this end, we have been developing a suite of tools to detect tampering in digital images. I will discuss two related techniques for exposing forgeries from inconsistencies in lighting. In each case we show how to estimate the direction to a light source from only a single image: inconsistencies across the image are then used as evidence of tampering.

Worth watching if you have the time. It gets a little technical in the middle but still interesting nonetheless.

Video Link here.

Thanks Stephen!

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