Representing data - Representing text, images and sound - KS3 Computer Science Revision - BBC Bitesize (2024)

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How are text, images, and sounds represented in a computer? ›

Computers use bits (binary digits) to represent data as ones and zeroes. Bits are the smallest piece of information a computer can store. Explore how computers use the binary number system to represent numbers, text, images, and sound with electrical signals in their circuits.

Data Representation is... Computers are digital machines, so ultimately all the data that we see on a computer is actually stored in electrical circuits as electrical pulses which we commonly represent as 1's and 0's. These 1's and 0's are known as Binary.

Sound is represented in computer systems through a process called sampling. In this, analog sound waves are converted into digital data by measuring the wave's intensity at various points, this data is then stored as binary code.

How are images represented in computer systems? Images in computer systems are represented as a matrix of pixel values. Each pixel holds numbers related to the intensity of the composition of Red, Green, and Blue (RGB values). These values range from 0-255 providing a wide range of colour variations.

When any key on a keyboard is pressed, it needs to be converted into a binary number so that it can be processed by the computer and the typed character can appear on the screen. A code where each number represents a character can be used to convert text into binary. One code we can use for this is called ASCII.

Digital systems represent text, image and audio data using integers. Text, images and other data can all be represented in binary.

An analogue sound wave is picked up by a microphone and sent to an Analogue to Digital (ADC) converter in the form of analogue electrical signals. The ADC converts the electrical signals into digital values which can be stored on a computer.

A waveform representation shows how the amplitude (y-axis) of a sound varies over time (x-axis). The figure below shows a waveform representation of a very short sound segment. Time is shown along the horizontal axis. Notice how the amplitude varies above and below the 0 line.

In common with most data that arises in the natural world, sound is analogue data. This means that it is formed and varies in a continuous manner; the particles vibrate continously until they run out of energy. In order to be stored and processed within a computer system, data must be held in binary form.

If you look closely at a computer screen, you will see that it is made up of millions of tiny squares. Each one of those squares is a pixel . To display an image, the computer tells the screen to show a particular colour for each of the pixels .

How image is used as the representation of data? ›

An image is broken down into the smallest single piece of information: a single color. This one color is represented as a number. An image is broken down into pixels. Each pixel holds the information about its color.

URL copied. [data capture] Data produced by scanning a surface with an optical or electronic device. Common examples include scanned documents, remotely sensed data (for example, satellite images), and aerial photographs.

Data in a computer system is represented in binary format, as a sequence of 0s and 1s, denoting 'off' and 'on' states respectively. The smallest component of this binary representation is known as a bit, which stands for 'binary digit'.

In binary code, characters are represented using a series of bits. Each character is assigned a unique binary pattern based on the character encoding scheme used. For example, in ASCII, each character is represented by a 7-bit binary number.

So a number such as 3 in 4 bits is represented as 0011 which is binary for 3.

A monitor is an electronic output device that is used to display images, text, video, and graphics information generated by a connected computer.