No Location Metadata? No Problem.

Many of today’s smart phones and digital cameras geo-tag images with GPS data that can be used to automatically categorize one’s images based on location. This information can, of course, be extremely useful in a criminal investigation such as a child abduction. Unfortunately, the GPS information is stored in the image EXIF data, which can be easily altered or removed. I will describe an amazing technique that can, using only the visual image content, narrow the likely locations where an image was taken.

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Seeing Behind the Camera

Imagine sitting in a room with a single open window. Across from this window is a white wall. Why isn’t an image of the outside world projected onto the wall? After all, the room and window are just a larger version of a camera (the window is the aperture and the wall is the sensor). The outside world is in fact imaged onto the wall — it is just very blurry. With some clever tricks, however, this image can be reconstructed, providing a view of the scene completely outside of the image frame.

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A Real-Life Lesson in Customer Service

If you tried visiting our site any time over the past week, it’s quite possible that you received a “site not found” message from your web browser. I can assure you that our site hasn’t gone anywhere, but finding the site has indeed been an intermittent problem due to issues at our domain registrar, Dotster. They are in the midst of a transition to a new management platform, and somehow that has triggered problems with the DNS tables that direct internet traffic to our site. As you can imagine, this is incredibly frustrating for us as we gear up for our first product launch.

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Photo Forensics from Thumbnails

At the time of initial recording, most cameras generate a thumbnail sized version of the full resolution image. Thumbnails are themselves stored as a JPEG image and embedded within the header of the full resolution image. A thumbnail is used to preview the image thus avoiding having to load and display the full resolution image. The process by which a thumbnail is created and stored is somewhat distinct across different camera manufacturers and photo editing software. As a result, the image thumbnail, an often over-looked part of a digital image, can be useful in an image forensic setting.

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Cloning: Biological or Photoshop?

Over the years I have worked on several scientific misconduct cases and have been surprised at the egregiousness and scope of the misconduct. From the biological to the astronomical, many scientific disciplines now rely on some form of scientific imaging. As a result, conclusions in scientific studies often rely on interpreting data in digital images. Because scientific images tend to be simpler than photographs of scenes and people, it is often much easier to manipulate them and can be much harder to detect the manipulations.

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