Tutorial 2: (Lossy vs. Loseless compression)
This week I am going to talk about the differences between Lossy and Loseless compression. Many of you may ask the same questions about what are Lossy and Loseless compressions. Simply, let’s start off with some terminologies.
Losseless compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. It laminates redundancy in the images in order to save space.
Lossy compression is a data encoding method which compresses data by discarding (losing) some of it. The procedure aims to minimize the amount of data that needs to be held, handled, or transmitted by a computer.
Lossless data compression is used in many applications. It can be used for archiving your original data so that you can edit later without losing any data. Editing and archiving are two places where lossless is an ideal. Zip file format is a perfect example of Lossless compression. By contrast, Lossy compression is most commonly used to compress multimedia data (audio, video, still images), especially, it is largely used for website by delivering your content to web customers or other uses.
The first image is the Lossless image, we can still have the same image quality, but the size of image is much smaller. Moreover, the second image is Lossy image, as you can see at the image (d) we are dramatically losing the quality of the image. The image looks so jagged.
There are four kinds of image file formats BMP, GIF, JPG, and PNG. Each format has its pros and cons, let’s take a brief look about the differences among these formats.
BMP- “Bitmap” is most common in Windows environments for uncompressed images.
GIF- “Graphical Interchange File” is a compressed technic that will throw out redundant pixels to save space. There is no loss of quality with GIF; however, it does lose the color depth information. GIF files are small and have capabilities to create animation images.
JPG- Joint photographic Experts Group is a commonly used method of lossy compression for digital photography (image). It is the most common format for storing and transmitting photographic images on the website visitors.
PNG- Portable Network Graphic is becoming increasingly popular. PNG files are typically lossless and very nice for presenting extremely high resolution images to users. Both GIF and PNG have transparent capability.
I hope some of you will get a better understanding of what Lossless and Lossy compressions are and better recognition of four types of image file format. When someone ask you about these relevant questions in the future, you have the ability the answer them all.
Work cited
http://en.wikipedia.org/wiki/Lossless_data_compression
http://computer.yourdictionary.com/lossless-compression
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