Computer Science GCSE
Data Encryption
Encryption plays a crucial part in allowing people to make effective use of computer networks.
Image Encoding
Just like anything, in order to be stored on a computer, images need to be encoded as numbers. The way this happens is important to understand.
In this section you need to be concerned about how Bitmap images work. Other image formats (such as JPEG) come into the section on data compression. The key things to understand in this section are:
- what Bitmaps are and how they are encoded
- what pixels are and how they are encoded
- how image resolution effects the quality and storage of an image
- what colour depth is and how it works
Exam questions will focus on knowing the technical terms and how they work together to encode an image. You may well find that there are links to either data compression or file storage and transfer rates.
Image representation - part 1 (detailed resource sheet)
Image representation - part 2 of the above.
Bitmap image - a simple grid showing how a black and white bitmap is encoded using pixels
Resolution and Colour Depth - slides from class.
There is a section of the BBC Bitesize site with notes about image encoding
, although not all of this is directly relevant to what you need to know. Focus on the points above - and the glossary at the bottom of the page is quite useful.