ENGSCI Week 3 Lesson 3 | Data Representation

Data

-Refers to the symbols that represent people, events, things and ideas. But in a technological standpoint, data refers to a text/character, number, color in a photograph or sound that needs to be processed by a computer.
-Since data and instructions cannot be entered and processed directly into our computers using human language, we use a binary number system to represent these values.

Data Representation

Refers to the form in which data is stored, processed, and transmitted in our computer.

Digitization

-Is the process of converting information, such as text, numbers, photo, or music, into digital data that can be manipulated by electronic devices.
-Once this information is collected, it is saved as a file with a specific type of file format.

File Formats

-txt files
-WAV/MP3 for music
-BMP and JPEG for images
-and many more…

Text files

-Contains text which is represented as binary in our computer.
-Inside of our text file, is a huge collection of numbers stored as binary.
-We can view this as a decimal value instead. Using our ASCII table from module 1, we can interpret this data as characters.

Digitization of Text files

Digital devices employ several types of codes to represent character data, including ASCII, Unicode, EBCDIC and their variants.

Encoding Scheme

-Digital devices employ several types of codes to represent character data, including ASCII, Unicode, EBCDIC and their variants.
-When we have some text and we want to either store it inside a computer, we need to convert it to binary representation because that’s the only language a binary-based computer can understand.

Encoding Scheme ASCII

-ASCII codes are used for numerals, such as Social Security numbers and phone numbers.
-Plain, unformatted text is sometimes called ASCII text and is stored in a so-called text file with a name ending in .txt.
-In order for us to create documents with styles and formats, formatting codes have to be embedded in the text.
-One of the most commonly used file formats that can format plain text into another form is the DOCX which is produced by creating a document using MS Word.

Digitization of Audio

-In digitizing sound or audio, we need to consider some parameters that determine the amount of information stored in a file and the quality of the digital sound, like the bit rate, size of the file and header/format header.
-When a sound is captured, our digital microphone samples the sound pressure thousands of times to create digital sounds.

Header

A part of audio’s metadata that provides specifications on the file type, sample rate, sample size and bit size of the file.

Bit rate

The number of bits that are conveyed or processed per unit of time.

Amplitude

-Larger numbers means higher sound pressure.
-There are thousands of amplitudes stored in every second of an audio.

Pixel

In our computer, pictures are made up of tiny square element.

Additive Primary Colors

-Each pixel is a combination of three color: red, green, and blue
-They can be mixed together to create any other color on our electronic display.

Digitization of pictures

-Just like in our audio, we also consider some parameters in digitizing our image like the height, width, file size and color depth.
-Suppose that we have a 4x4 pixel image with a 24bit color depth. That means 8bit for red, 8bit for green and 8bit for blue.
-And we all know that an 8bit is equivalent to 1byte and the smallest value that it can store is 0 and the largest is 255