[SIGCIS-Members] Alvy Ray Smith's "The Biography of the Pixel"

Brian Randell brian.randell at newcastle.ac.uk
Mon Sep 6 04:29:16 PDT 2021


I strongly  recommend Alvy Ray Smith's  "The Biography of the Pixel", just published by MIT Press:

Amazon has only two reviews as yet , but both are informative, well-argued and very enthusiastic:

I have to declare an interest - I was consulted for the section of the book on the early history of digital computers, and am listed in the acknowledgements. However only now have I seen the whole book, and I am *very* impressed. I attach, as a small sample of the book, a scan of three pages from the Introduction.

I'm still in the middle of reading the book myself, but I think it's terrific - I agree with every word of the two (at time of writing) Amazon reviews (by Potash and McGee).


Brian Randell


From the Introduction "Beginnings: A Signal Event":

Even as late as 1800, just two centuries ago, a picture of Napoleon crossing the Alps AND the canvas on which Jacques-Louis David painted it AND the oil paints he used were an integral unit. Imagine that you wanted to share Napoleon's delightfully hagiographic picture (figure 0.2) in Europe with a friend in New York. There were no cellphones or video cameras yet, not even such a thing as a photograph. The only way to display him in New York was to transport the one physical painting there-if you dared. An engraving, etching, or sketch might help, but those were only better or worse copies--new images that would never fully and faithfully capture the original. Through all that time a painting and its medium of creation were inseparable. No one even conceived of separating the two. What could a picture be, independent of its medium?
Then in the early nineteenth century photography was invented, ushering in the world of what we now call "the media." Faithful reproduction was upon us. Movies followed in the late nineteenth century and television in the early twentieth. All media then were analog smooth and continuous. And a picture could be transferred from one medium to another a hint that something, after all, about a picture floats separate from its medium.
The notion of the digital discrete and spiky-didn't fully exist until 1933. At midcentury, 1950, there were only a couple of digital pictures in existence. The few people who knew about them actually thought they were frivolous distractions from the more serious projects of digital computers. All the other pictures in the world were made and viewed with analog means-oil on canvas, ink on paper, and chemical emulsion on photographic film, to name a few.
But at the millennium, 2000, there was an unheralded event--the Great Digital Convergence: a single new digital medium-the all-encompassing bit replaced nearly all analog media. The bit became the universal medium, and the pixel--a particular packaging of bits conquered the world. It became possible to remove a painting, so to speak, from its canvas. As a consequence, most pictures in the world are now digital. Analog pictures have all but vanished relative to ubiquitous digital imagery. Museums and kindergartens are among the few reliable places to find the analog. This book heralds that signal millennial event by celebrating Digital Light - the vast realm that includes any picture, for any purpose, made from pixels. It extends from parking meters to virtual reality, from dashboards to digital movies and television, from CAT scans to videogames to cellphone displays, and many, many more--anything mediated by pixels.
What's puzzling about the new medium is that you can't see it. Bits, and pixels made of bits, are invisible. Pixels are not to be confused, as they often are, with the little glowing areas on a screen, called display elements. The technical heart of this book is the explanation of how to make pictures composed of invisible stuff visible-how to convert digital pixels to analog display elements.
That the Great Digital Convergence happened at the millennium was just a coincidence, but a convenient one. Pixar released the first digital movie, Toy Story, in 1995. The first broadcast of the new high-definition television (HDTV) signal was in 1998. A digital camera of sufficient quality to threaten film cameras astonished the market in 1999. The digital video disc, or DVD, debuted in 2000. Apple introduced the ubiquitous iPhone in 2007. What had been ink and paper, photographs, movies, and television became-in a blink of the historical eye-just bits. The change was so fast that young people today may have never experienced non-digital media-outside those last bastions of the analog: art museums and preschools.
We are all now aswim in an ocean of pixels. carry billions of them on my person, and I suspect that you do too. But curiously there's been little serious notice taken of this pervasive change in our daily experience. Perhaps this is because most people haven't realized that Digital Light is single unified technology. The notion is new. Making it clear is a major purpose of this book.

Foundations: Three Great Ideas

Just three ideas-waves, computations, and pixels underlie all the apparent complexity of Digital Light. Each idea is intuitively simple, profound, and beautiful. These are the technological cornerstones of our modern world, and you don't need mathematics to understand them. The first three chapters (part I of this book) present these foundational ideas with the surprising and fascinating stories of the people who made them possible.
Waves are an analog idea. You probably know that music is made of simultaneous sound waves of different frequencies (pitches) and amplitudes (loudnesses). Two centuries ago the Frenchman Joseph Fourier extended that notion to all our sensory experience. Everything we see and hear is a sum of waves. It's all music. In this book I show you how to see the music in a visual scene.
Computers are a digital idea. Machines that make computations go fast are the very exemplars of the digital in ordinary life. But the idea of computation dates back only to 1936 when the Englishman Alan Turing invented it to capture the notion of a careful, precise process. That might sound plodding and boring, but the consequences are anything but. Computers are humankind's most malleable tool. And their awesome speed is the most consequential engineering miracle of all time. With that speed, computers amplify what we puny humans can do by unimaginable amounts.
But all of the mind-boggling, world-changing power of computers really reduces to a careful flipping between two states, often named 0 and 1. Computation is all bits. That may sound trivial, but I hope to inspire you with the unexpected beauty--and mystery--inherent in computation. Again, no mathematics required.
The most important but least known of the three fundamental ideas is the underlying theme of this book: you can pass back and forth between waves and bits - between the analog and digital worlds. The idea dates back only to 1933 when the Russian Vladimir Kotelnikov established it as we know it today. Its formal name is the Sampling Theorem. This entire book-being a biography of the pixel, with pixel being our name for a sample of the visual world - is about sampling. Pixels are invisible bits that represent visible waves. My fervent intent is that you understand this piece of magic and be amazed by how it works. No mathematics is required here either.
Now that I've said no math required three times in two pages, you might be thinking: But what if some of us care about the math? For you - but really for all my readers - I provide an online annotations site at http://alvyray.com/DigitalLight/. There you will find additional details about people, places, and events that would have made this book too unwieldy to fit between its physical covers and you will find as well mathematical equations to support the magic of Digital Light and the pixels that make it possible. There's a common misconception that a pixel is a little square of color. But in fact, the pixel is a profound and abstract concept that binds our modern media world together. It's the organizing principle of Digital Light.
A visual scene consists of an infinite number of points of color. Infinite is, by definition, too large to deal with. So how can we replace a smooth visual scene with only a finite number of discrete bits the pixels - and not lose an infinity of information between them? The Sampling Theorem tells us how to do it. It's the secret that makes the modern media world work.
Sampling, which depends on Fourier's waves, was created almost simultaneously with computation in the mid-1930s. Sampling met computation and conceived a child, Digital Light, the subject of this book.


School of Computing, Newcastle University, 1 Science Square, Newcastle upon Tyne, NE4 5TG
EMAIL = Brian.Randell at ncl.ac.uk   PHONE = +44 191 208 7923
URL = http://www.ncl.ac.uk/computing/people/profile/brianrandell.htm

School of Computing, Newcastle University, 1 Science Square, Newcastle upon Tyne, NE4 5TG
EMAIL = Brian.Randell at ncl.ac.uk   PHONE = +44 191 208 7923
URL = http://www.ncl.ac.uk/computing/people/profile/brianrandell.html

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