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AI Explorers 3-5 / Week 02 / Tuesday
2/6
Week 02 · Sensors and Perception

Tuesday

From signals to meaning
// How computers sense the world
⏱ about 15 min

Tuesday: From Signals to Meaning

Rocket holds up a new photo from Nova's camera. It is a blur of green and brown.

"The camera picked up light," he says. "But what is it?"

Raven tilts her head. "What do you notice? There are pointy shapes, like leaves."

Nova blinks her lights. "A signal is only the start," she hints. "What does it mean?"

Rocket looks again. Maybe it is a plant!

What is perception?

Perception means getting meaning from signals.

Your eyes pick up light. Your brain says, "That is a cat."

A computer camera picks up light too. Then a program tries to work out what it shows.

Making computers see and hear is one of AI's biggest wins.

A sensor picks up a signal
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The signal goes to the computer
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A program looks for meaning
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The computer makes a guess
PUT PERCEPTION IN ORDER
  • ?The camera picks up light from a scene.
  • ?The signal goes into the computer.
  • ?A program looks for meaning in the signal.
  • ?The computer guesses: this photo shows a plant.
WHY THIS EXERCISEPerception starts with a signal and ends with meaning.
PERCEPTION CHECK
  • Read the question.
  • Tap your answer.
What does perception mean?
A microphone picks up a bark. The computer guesses "dog." Which part is perception?
Which comes first?

Perception can be wrong

Sometimes a signal is fuzzy. A photo can be dark or blurry.

A sound can be very quiet, or mixed with other noise.

Then the meaning is harder to find. The guess might be wrong.

That is true for people and for computers.

StatementTrue or false?
Perception means getting meaning from signals.?
A blurry photo is easy to understand every time.?
A computer can make a wrong guess from a fuzzy signal.?
The signal comes after the meaning.?
WHY THIS EXERCISEFuzzy signals make perception harder for people and for computers.
Getting meaning from signals is called ____.
A camera picks up ____.
A microphone picks up ____.
Can a blurry photo lead to a wrong guess? Type yes or no.
WHY THIS EXERCISEA fuzzy signal makes meaning harder to find, so guesses can be wrong.
CLEAR OR FUZZY SIGNAL?
  • Read the question.
  • Tap your answer.
A photo taken in a dark room. Clear or fuzzy?
A quiet voice next to a loud fan. Clear or fuzzy?
A sharp photo of a rock in bright light. Clear or fuzzy?
Try it
Look at an object through a glass of water or wax paper.
Can you still tell what it is? What clues help you?

You learned a big word today: perception! Tomorrow you test your own perception in the lab.

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