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data representation text images
A LevelComputer Science~4 min read
Overview
This lesson explores how computers represent text and images digitally. We will cover character encoding schemes like ASCII and Unicode, and delve into the principles of representing images using pixels, colour depth, and resolution.
Introduction to Character Sets and Encoding
Computers process information in binary, so every character, including letters, numbers, and symbols, must be converted into a binary code. A **character set** is a defined list of characters that a computer can recognise and process. Each character in the set is assigned a unique binary code throug...
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Key Concepts
- Character Set: A defined list of characters that a computer can recognise and process.
- Character Encoding: The process of assigning a unique binary code to each character in a character set.
- ASCII: American Standard Code for Information Interchange, an early 7-bit character encoding standard.
- Unicode: A universal character encoding standard designed to represent text from all writing systems, using variable-length encoding (e.g., UTF-8, UTF-16).
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Exam Tips
- →Be able to calculate the storage requirements for text given the character set size and number of characters, and for images given resolution and colour depth.
- →Clearly distinguish between ASCII, Extended ASCII, and Unicode/UTF-8, explaining their advantages and limitations.
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