Cameras, Photos and People

Tuesday , 23, July 2019

Camera technology is not what it was a generation ago. Photogaphs and videos captured using smartphones have revolutionized how we see the world, how we share information and how we document our lives. But few understand the technologies involved and how they are analyzed. In these next few posts I want to share what I know about this topic, which is limited and will be getting outdated by the time I finish typing this introduction.

Most of us use mobile phones because they are incredibly convenient. The actual phone function is only one of many that we use though; another important feature are the cameras. With builtin 12 megapixel cameras being no big deal, we take photos of food, scenery, friends, and of course selfies. What we don’t realize is that it’s important for “big marketing” to identify cameras, and the photos they take, and match them to people.

Surveillance cameras are going through an unprecedented population growth, and feed data into AI systems that identify us by our faces and our gait. They combine this with realtime location data from our phones and suddenly every detail of your activity since you stepped out of your house is known and recorded.

We post them to social media sites as if the world needed to know where we ate lunch. We pull them into apps to manipulate them, put cute sunglasses on our selfies and use apps to share them with the entire planet for all of recorded history. Welcome to a tiny preview of what we can expect in the future.

Image credit: Public Library of Science:

People dramatically underestimate how much information is available to anyone analyzing their posted photographs. Aside from information about your camera which is linked to you, a lot of extraneous data can be extracted from photographs. For example, shown above is a system that identifies people not in line of sight of a camera by their reflection in someone’s cornea! In the image above, we see five individuals identified from the reflection in the eye of a person in view of a camera.

Identifying images and determining that they came from a specific camera, or were manipulated with a computer program associated to a specific individual is important. Photographs are used as evidence in courtrooms, and forensics is used to support the validity claims. However, if you are determined to post a selfie on a dating site, you should take precautions to not include too much evidence that identifies you.

Next we’re going to take a closer look at camera fingerprinting. You might be surprised at the sophistication of the techniques used.