In this paper we present online encoding and decoding algorithms for an infinite input alphabet. The well-known encoding algorithm that explicitly constructs the optimal codes is proposed by Huffman. This algorithm is clearly inappropriate for online encoding because the whole input data are not known before starting the process. We propose an algorithm that can be encoded while the input data ...

While compressing a file with a Huffman code, it is possible that the size of the file grows temporarily. This happens when the source letters with low frequencies (to which long codewords are assigned) are encoded first. The maximum data expansion is the average growth in bits per source letter resulting from the encoding of a source letter with a long codeword. It is a measure of the worst ca...

This research paper proposes a method for the compression of medical images using an efficient hybrid algorithm. The objective of this hybrid (DWT,DCT and Huffman quantization) scheme is to calculate the compression ratio, peak signal to noise ratio and mean square error by changing the DWT level and Huffman quantization factor. The goal is to achieve higher compression ratio by applying differ...

For some applications where the speed of decoding and the fault tolerance are important, like in video storing, one of the successful answers is Fix-Free Codes. These codes have been applied in some standards like H.263+ and MPEG-4. The cost of using fix-free codes is to increase the redundancy of the code which means the increase in the amount of bits we need to represent any peace of informat...

We describe the implementation of a data compression scheme as an integral and transparent layer within a full-text retrieval system. Using a semi-static word-based compression model, the space needed to store the text is under 30% of the original requirement. The model is used in conjunction with canonical Huffman coding, and together these two paradigms provide fast decompression. Experiments...

This paper describes the derivation of the T-Complexity and T-Information Theory from the decomposition of finite strings, based on the duality of strings and variable-length T-Codes. It further outlines its similarity to the string parsing algorithm by Lempel and Ziv. It is intended as a summary of work published mainly by Titchener and Nicolescu. 1 A brief Introduction to T-Codes This paper f...

We present an approach to compress arbitrary files using a Huffman-like prefix-free code generated through the use of a genetic algorithm, thus requiring no prior knowledge of substring frequencies in the original file. This approach also enables multiple-character substrings to be encoded. We demonstrate, through testing on various different formats of real-world data, that in some domains, th...

Test compression / decompression is an efficient method for reducing the test application cost. In this letter we propose a response compression method based on Huffman coding. The proposed method guarantees zero-aliasing and it is independent of the fault model and the structure of a circuit-under-test. Experimental results of the compression ratio and the size of the encoder for the proposed ...

Contour representation of binary object is increasingly used in image processing and pattern recognition. Chain code and crack code are popular methods of contour encoding. However, by using these methods, an accurate estimate of geometric features like area and perimeter of objects are difficult to obtain. Midcrack code, another contour encoding method, can help to obtain more accurate estimat...

An n symbol source which has a Huffman code with codelength vector Ln = (1, 2, 3, · · · , n − 2, n − 1, n − 1) is called an anti-uniform source. In this paper, it is shown that for this class of sources, the optimal fix-free code and symmetric fix-free code is C∗ n = (0, 11, 101, 1001, · · · , 1 n−2 { }} { 0 · · · 0 1).