What is a pixel?

16 September 2019
Last week, Pixar co-founder and first director of computer graphics at Lucasfilms, Dr Alvy Ray Smith joined our Dean of Engineering to discuss the immeasurable impact of one 20th century invention: the pixel.
Dean of Engineering, Professor Willy Zwaenepoel has described Dr Smith as a “true pioneer in computer graphics”.

Dean of Engineering, Professor Willy Zwaenepoel has described Dr Smith as a “true pioneer in computer graphics”.

What is a pixel?

If you ask most people, the majority will say pixels are small squares that make up digital images. 

However, this isn’t entirely correct, according to Pixar co-founder and world-renowned computer scientist, Dr Alvy Ray Smith; keynote speaker at last week's Dean’s Lecture hosted by the Faculty of Engineering Dean, Professor Willy Zwaenepoel.

“Pixels have never been little squares,” he explained. Instead, they’re “the unit of everything in terms of graphics and light” that are represented as the tiny squares or dots you see when you look closely at a digital screen.

This new contemporary vision, Dr Smith says, is what underpins every digital device, giving the world access to almost any medium in a digital format.

From Instagram posts to blockbusters, “digital light is any picture made of pixels -- that’s almost every picture in the world now,” he said.  

Although the pixel first appeared in the late 1940s, with coloured pixels soon following in 1967, the most revolutionary shift took place in the late nineties, turning the analogue world digital.

This pivot is what Dr Smith calls the Great Digital Convergence -- a “huge event at the turn of the millennium where all old media disappeared, replaced by a single new one -- digital, of course. All media collapsed into one and we began picking flowers from that garden,” he said.

Thirty years ago, we may have read paperbacks, posted letters or watched films captured on 35mm. In 2019, digital devices are ubiquitous, used to access photographs, paintings, films, books and games all without the original analogue medium with which they would previously have been created.

The future of pixels - and beyond

The computers Dr Smith first worked with were huge, ponderous and slow. Simple computer chips were capable of processing large swathes of information, but would take a long time to perform simple functions.

Over the past 50 years, computing has developed rapidly, proving Intel co-founder, Gordon E. Moore’s 1965 theory, Moore’s Law, that the speed and capability of computers will continue to increase, while manufacturing costs will decrease.

Some experts now believe computing will reach its physical limit in the next 10-20 years. 

Dr Smith doesn’t agree, instead believing there will be no plateau, with computing power will continue to rise exponentially.

“Anything good about computers, such as higher speed or more memory, gets better by an order of magnitude every five years,” he said, meaning that computers today are over 100 billion times more powerful than they were in 1965.

If history is anything to go by, it’s a trajectory almost impossible to imagine.

About Dr Alvy Ray Smith

Co-founder of both Pixar and Altamira, Dr Smith was the first director of computer graphics at Lucasfilms, and saw the birth of the personal computer, internet, and some of the earliest colour pixels.

While at Lucasfilm he directed the first use of full computer graphics in a successful major motion picture, Star Trek II: The Wrath of Khan. 

The team he formed for these early pieces later created Tin Toy, the first computer animation ever to win an Academy Award, and the first completely computer-generated film, Toy Story.

Dr Smith was one of the first people to ever complete post-doctoral studies in computer science, which he completed at Stanford University.

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