China
Africa
Explore chapters and articles related to this topic
Images and Image Display
Published in Julio Sanchez, Maria P. Canton, William Perrizo, Space Image Processing, 2018
Julio Sanchez, Maria P. Canton, William Perrizo
LZW is a compression technique suited to color image data. The method is named after Abraham Lempel, Jabob Ziv, and Terry Welch. The algorithm, also known as Ziv-Lempel compression, was first published in 1977 in the IEEE Transactions on Information Theory. The compression technique was refined by Welch and the results published in another article titled “A Technique for High-Performance Data Compression” that appeared in Computer, in 1984. LZW compression is based on converting raw data into a reversible encoding in which the data repetitions are tokenized and stored in compressed form. LZW compression is used in many popular data and image compression programs, including some versions of Compuserve GIF image data encoding format and in some variations of the TIFF standard. Notice that LZW compression has been patented by Unisys Corporation; therefore, its commercial use requires a license from the patent holders.
Image Compression
Published in Vipin Tyagi, Understanding Digital Image Processing, 2018
Lempel–Ziv–Welch (LZW) coding algorithm is a lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch in 1978. Lempel–Ziv–Welch (LZW) coding is a dictionary coding scheme, in which the source input is encoded by creating a list or a dictionary of the frequently recurring patterns. The frequently occurring patterns are located in the source input and encoded by their address in the dictionary. The algorithm is easy to implement and can be implemented in hardware. This algorithm is used in GIF image format.
Multimedia Data Compression
Published in Sreeparna Banerjee, Elements of Multimedia, 2019
The LZW compression method was derived from LZ78 by Jacob Ziv and Abraham Lempel and later invented by Terry A. Welch in 1984 who had published his considerations in the article “A Technique for High-Performance Data Compression.” LZW is an important part of a variety of data formats. Graphic formats like gif, tiff (optional), and Postscript use LZW for entropy coding.
An email-based high capacity text steganography using repeating characters
Published in International Journal of Computers and Applications, 2021
Step 1: In the first step, the secret message is converted to a stream numbers using the LZW compression [14]. LZW is lossless dictionary based adaptive compression algorithm. LZW compression works by reading a sequence of symbols, grouping the symbols into strings, and converting the strings into integer codes. Decompression converts codes back into strings, obtaining the original symbols. 6. After that, these numbers are converted to binary and a bit stream is generated from the secret message.
A Novel Hybrid Medical Data Compression Using Huffman Coding and LZW in IoT
Published in IETE Journal of Research, 2022
Hossein Mohammadi, Abdulbaghi Ghaderzadeh, Amir Sheikh Ahmadi
To this end, a major change should be applied in the LZW dictionary preload with all possible characters that might occur. LZW compression substitutes the string of characters with a code. The LZW algorithm is a dictionary-based lossless data compression algorithm [39]. This compressor maintains the records with characters read from a document for compression. Each character is represented with an index number in the dictionary.