This is a deeply personal blog post, written by Kairos in-house journalist, Andrew Loader.

I write this having just lost my best friend and mentor of more than 25 years, John Waldron.

On the night of his funeral I was suffering a disrupted sleep, remembering the good old days. The thing that struck me was just how vividly I visualised his face. There are few photos of John - he hated having his picture taken with a passion. Yet John's face will be forever ingrained in my mind: the cheeky grin, the vivid blue eyes, the well-worn leather-like complexion, the bushy grey beard (that only got trimmed for weddings and funerals), the nearly bald pate, with just wisps of hair around the edges, his absent teeth which added character to his smile.

I know it is not long since his passing, but I am surprised how well I remember his face. It was a face that was distinctively his - so clearly, and so individually, John - Little John to his friends.

So at 1am, somewhat bleary-eyed and desperately craving sleep, I began to think about the importance of how we all have distinctively personalised faces.

Your Face

Your face is the most recognisable part of you.

Your face is what makes you unique.

When you visualise people from your past, it is their face that pushes forward and jumps out at you from your mind.

You visualise your girlfriend, boyfriend, wife, husband, soulmate, friend. A smile beckons. The most vivid part of your vision is the memory of their face. Maybe it's their eyes appealing to you, or the slightly lopsided grin.

When people pass on, and you grieve them, it is their face that reappears in your mind to comfort you. You can see their lips move, soundlessly hear them, as you remember happy days that have passed.

On the day of your wedding, your ultimate moment of exhilaration is both hearing and seeing your beloved's lips move to make the words "I do".

You will always remember that twinkle in their eyes, that little twitch of the nose, the upward curves at the outer edges of their mouth, as they smile at you.

You remember the full-bellied laughter in those oh-so-happy days of your past - the memories you most cherish, the smiles and expressions of joy. You can still visualise the wide-opening of the eyes in delight.

Of course, not all days are happy. There are memories of your friends, partners and lovers with frowns, with scowls, with tears dripping from their eyes, besmirching their faces. In the case of wives or girlfriends, it may be the smearing of their make-up that leaves the most vivid image in your memory.

Sometimes you may have stumbled in late, perhaps a bit worse for wear. Perhaps your most vivid memory is worry on a loved one's face - or perhaps once you have arrived home their face may have shown signs of relief - whew, you are safe!

Then in the bad times, all you might see is pain and hurt. Disappointment perhaps. Dejection. Despair.

Our Face is the Window to Our Soul

We are all human beings. We have a myriad of expressions. There is an old expression saying that our "eyes are the mirror of the soul".

But in reality it is more than that. According to Dr Steven Gutstein of RDIConnect the entire face is in reality the window to our soul. "What distinguishes referencing from eye contact is that referencing is all about looking at your social partners faces to gain important information about what they are feeling, perceiving or desiring".

Our face gives away all of our inner feelings. Only the best poker players can hide the microexpressions that we nearly all briefly display.

And each of our faces are different. Fat, thin, round, oblong, square (well, none of us really looks like a Lego brick). I might have big ears. You might have a hooked nose. My teeth may be crooked. Your eyes might be bright and vivid. I might have bushy eyebrows. Your face might be a minefield of freckles.

Our Faces are Truly Unique

That is the joy of being human. Our face is a part of us that is ours and ours alone, but we can share the visions of that face with all that we come into contact with as we go about living.

My grandfather had the misfortune of going blind for the last decade of his life. But he had many years of sight prior to this. He at least had the opportunity to build up a memory bank of the faces of those nearest and dearest to him. Of course, we never aged for Pop - our faces, as he remembered them, became eternal.

Face recognition is inherent. It is an important part of being human.

Programmers have tried to replicate facial recognition using computers. They too have tried to find ways in which computers can recognise and differentiate peoples' faces. Facial recognition can be part of a computer’s memory as well. Developers have even managed to measure and display emotions, for instance using the Kairos Emotion Analysis API. I wonder how long it will be until computers can actually feel these emotions too?

There is much joy in having face recognition memory. In my sad or indecisive times I only need to think back, to visualise the face of my old mentor, and I can see his lips move and almost hear his help and advice. He lives forever inside my head. Indeed, he lives inside the heads of all those who cared for him.

Ironically, John was old-school and a technophobe. He certainly was not into having his face recognised. With a friendship that goes back more than 25 years, there are no photos in existence that have the two of us in. He was proud of me when he learned I began working for Kairos, though, and told his friends and family about it. I am sure he would have chuckled at the irony of his tale appearing on a facial recognition technology website - just as long as his photo was never published!.

Rest in peace, John. You will not be forgotten. Your face depicted intense character and a lifetime of experience. It will forever be remembered.