ONE of the tragedies of children who go missing is that the longer they are gone, the harder they are to find. Their faces can change so rapidly that years later it is hard to imagine what they look like.
But there are now ways round that. At the National Center for Missing & Exploited Children (NCMEC) in Alexandria, Virginia, we are using “age-progression” techniques to create pictures of how children who have been missing a long time might look today.
The techniques are a combination of art and science. There is no such thing as face-ageing software that can “age” a face from a photograph at the touch of a button. Instead, our artists use off-the-shelf photographic manipulation software – and their artistic skills.
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The artist starts with a clear photograph of the missing child, along with photographs of their biological parents and siblings at or around the child’s current age. The software allows the artist to merge the photograph of the missing child with a picture of a parent or sibling. First the two sets of eyes are aligned, then the face of the missing child is stretched to match the growth of the older family member. The two images are then merged. The process allows the artist to “borrow” the mature facial features of the relative, while preserving the unique genetic likeness. The artist must decide how much of each face to use in the merging, and the software allows them to make very subtle changes. Once the artist is satisfied that the face looks the correct age, the final stage is to add a modern hairstyle and clothes – again at the artist’s discretion.
Artificially ageing the face of a child is very difficult because children’s faces grow and change rapidly. Most facial growth occurs shortly after birth, but it continues through the teens. The face continues to grow out and down until the age of about 20 for males and 16 for females. By age 20, all facial growth ceases. The age progression artist has to be very aware of the facial characteristics that define a person’s face at a particular age, and how they will change. In young children, the eyes appear larger and rounder than those of adults or teens. The bridge of the nose is broader and less defined. The neck is shorter and thinner. As we age, the eyes begin to elongate, the nose becomes more defined and the face gets longer. Baby fat eventually gives way to identifiable features.
One crucial factor the artist must always bear in mind is what I call “unique genetic likeness”. This is the recognisable facial quality that separates one person from all others. This quality is by far the most important aspect in age-progression technology, and the most elusive. It has to do with the way the eyes, nose and mouth relate to each other, and it is apparent only when looking at the whole face rather than the individual parts. If the artist fails to preserve this relationship then the final image will be of little value. While lifestyle and diet can change some aspects of how a person looks, the genetically driven facial features will remain the same.
Ageing adults is easier than ageing children. With adults, you have to account for changes caused by gravity. As fat begins to build in the face, particularly around the eyelids and cheeks, gravity causes these deposits to sag. Depending on the age of the adult, the normal facial lines begin to deepen. The bridge of the nose becomes more refined and shadows begin to form over the eyes. All these changes are easier to take account of than the rapid structural growth that transforms children’s faces.
How accurately can we age a face? As with anything involving art, it depends on the eye of the beholder. There are many variables, but the true measure is in the results. When someone recognises a missing child after seeing an age-progressed image in a newspaper or on television, or on a missing children’s website or flyer, then the image has done its job.
A few years ago, I age-progressed the face of a girl who had been missing since the age of 5. She was now 12. The child was the victim of a typical non-custodial parental abduction. Her age-progressed image appeared on a national advertisement that is mailed to millions of homes each week. The child and her siblings were recovered after neighbours recognised her image and called the police. They were eventually returned to their mother.
I have learned that with age progression images, the public is very forgiving. If we manage to preserve a recognisable portion of a person’s genetic likeness, and the right person sees the image, they’ll make the connection. While we strive for perfection, we cannot always please everyone. Months later I had the pleasure of meeting the young girl and her family. I couldn’t help but ask if she thought my age-progressed image looked like her. Her very honest answer was “not really”.