I have written this article to provide an insight into the world of data compression. It's objective is to provide those interested in photography a basic understanding of how image data is compressed. Some of you may of come across debates on the benefits of Raw format over the Jpeg format. Many of the points raised about the Jpeg format are basically true but based on guesswork due to the lack of detailed knowledge on it's internal workings. I intend to examine and explain the Baseline Jpeg compression methods strengths and weakness.
Let me first explain how and why data can be compressed. In order to understand this there are some concepts you need to grasp.
To illustrate the last point consider a sheet of A4 size paper with some printed text.
Compared to "Hello World" the Electricity Bill contains more information such as Address, telephone number, price, usage, date, etc. Therefore the first example will fit onto a smaller sheet of paper and a larger sheet is required for the Electricity bill.It then follows that a smaller envelope or container can be used to hold the first example.
Key point being there is a lot of wasted ( redundant - unused ) space on
the "Hello World" example. Data Compression is about finding a more
efficient code to hold the information. If the information is already
stored efficiently with no waste then it will not be easy to compress it