Lossless compression algorithms reduce file size with no loss in image quality.
- When the file is saved it is compressed, when it is decompressed (opened) the original data is retrieved.
- The file data is only temporarily 'thrown away', so that the file can be transferred.
Compression lossless techniques
- Huffman Coding
- Huffman Coding of Images
- Adaptive Huffman Coding
- Arithmetic Coding
Huffman compression is simpler and faster but produces poor results for models that deal with symbol probabilities close to 1.
Arithmetic coding achieves compression rates close to the best possible for a particular statistical model, which is given by the information entropy.
Lossless compression methods include RLE (Run Length Encoding), string-table compression, LZW (Lempel Ziff Welch) and zlib.