AI Anatomy Class · Part 1 · AI speaks in numbers

6. Everything is a number

Q. How does a computer remember photos, songs and letters?

1. Inside a computer, photos, songs and letters are all stored as numbers. Today, let's look at those numbers up close.
2. Zoom into a photo and you see tiny squares called pixels. Each pixel is one number for brightness: 0 is black, 255 is white.
3. Color photos use three numbers per pixel: red, green and blue. Mixing those three lights makes every color.
4. Sound is vibrating air. We measure the vibration over and over and write down numbers: a CD does it 44,100 times a second.
5. Letters too: every character has its own number. "A" is 65 and "B" is 66. This numbering system is called Unicode.
6. But the numbers carry no meaning. A and B are neighbors, yet different letters. Small "a", the same letter as A, is far off at 97.
7. So AI turns words into bundles of numbers that do carry meaning. Those bundles are vectors. See you in the next chapter.

Chapter summary

• A photo is stored as a brightness number (or red, green, blue numbers) for each pixel.
• Sound is the size of the vibration measured many times a second; letters are Unicode numbers.
• Code numbers carry no meaning, so AI uses bundles of numbers that do: vectors.