Forensic Image Analysis
Selfies can be used to identify age of adolescents

Did you know you can accurately guess the age of a child from the diameter of their pupils? Pupil diameter seems to increase pretty predictably as a child grows, unlike other features of the face, according to Neeka Parker’s assessment of pertinent studies in her paper “Age Estimation of Adolescents Using Eye Measurements from Various Angles in Videos.”

Did you also know that kid’s love selfies? I probably don’t have to tell you that a selfie is a picture a person takes of him or herself. Because of this, the selfie is often at a unique angle from other pictures. Selfies, though, are almost epidemic, especially among younger people and millennials. (Over 55% of millennials say they’ve taken a selfie.) Forensic analysis of selfies as regards to a young person’s age could be an important part of a legal case.

But can you figure out a child’s age from their pupils in a selfie? In her study, Neeka Parker wanted to find out what selfie angles and cellphone pictures did to the angle of an adolescent face and to how well you could see their pupils.


With permission from their parents, Parker gathered twenty-one children from ages eleven to nineteen, twelve girls and nine boys, some African-American and some Caucasian, with one Mayan. Most of these children had brown eyes, which will be important later.


With these participants gathered, Parker had to deal with some variables in the way eyes change. Pupils can be affected by lighting, medication, or even just a person’s mood. Parker asked her participants questions about their mood and medication so she could account for those variables. And, of course, she made sure the lighting was controlled.


Parker took pictures with an iPad and a Nikon D3100 camera and video with the Nikon. She took reference pictures and then had the participants take selfies, which were analyzed in Photoshop.


Selfie Forensics
In the end, Parker found that since most of her participants had brown eyes, generally she could only distinguish the pupil on the Nikon images but not the iPad images or the Nikon video stills. This made further analysis and measurements difficult. Note that the pupil diameter is the most important part of judging a child’s age by their face and that brown is the most common eye color.


Although Parker did compare her device, the iPad, to other smartphones and concluded that camera hasn’t improved, at least in the iPhone, it would have been useful if Parker had included more imaging devices, including actual cellphones in her study. In my experience, a teenager would rather be caught dead than using something clunky like a tablet or iPad to take pictures. Selfies are the domain of the smartphone, which is light and convenient to use when taking pictures with your arm stretched awkwardly.

What does this mean for determining children’s age in the forensic image analysis of selfies? Parker says more research needs to be done. But right now it looks like whether your selfie is useful depends on what device it was taken with. She also pointed out it’s possible other ways besides pupil diameter may be needed to judge age in a selfie. But as phone cameras get better and better, it’ll get easier to figure out a child’s age and tons of other useful information, from the humble selfie.

Want to know more about forensic image analysis of selfies? You can read Parker’s research paper here.