Large networks of IBM computers use it. So do high-definition television, modems and a popular electronic device that takes the brain work out of programming a videocassette recorder. All these digital wonders rely on the results of a 40-year-old term paper by a modest Massachusetts Institute of Technology graduate student—a data compression scheme known as Huffman encoding. In 1951 David A. Hu...

This paper presents the architecture and design of a high-performance asynchronous Huffman decoder for compressed-code embedded processors. In such processors, embedded programs are stored in compressed form in instruction ROM, then are decompressed on demand during instruction cache refill. The Huffman decoder is used as a code decompression engine. The circuit is non-pipelined, and is impleme...

4ompetitively optimal coding is considered and the following is proved. 1) If the competitively optimal code exists for a glven source probability p(z), then it also attains the minimum expected codeword length 2) If the Huffman code tree for p(z) is unbalanced in probability weight, then the competitively optimal code does not exist. Furthermore, the relation between competitively optimal codi...

New concepts are defined, in particular the quasi-question or vertex with an outgoing arc of zero probability. A quasi-questionnaire is a probabilistic homogeneous (rooted) tree with quasiquestions. It is shown that every instantaneous code is a quasi-questionnaire with precise restrictive conditions; it may also be a questionnaire, without an arc of zero probability. Also, an approximation is ...

This paper proposes a method for the compression of color images by Haar transform, quantization and construction of minimum redundancy code using conventional Huffman coding. Wavelet compression is accomplished by decomposing the row and column of the image matrix using the Harr transform. And the reconstruction of the image is feasible just from 1/4 of the decomposed image and even 1/16 of th...

The Huffman tree is a well known concept in data compression discovered by David Huffman in 1952 [7]. A Huffman tree is a binary tree and represents the most efficient binary code for a given alphabetwith respect to a distribution of frequency of its characters. In this paper, we associate any Huffman tree of n leaves with the point in Qn having as coordinates the length of the paths from the r...

A strategy for computing upper code-length limits of AC Huffman codes for an 8x8 block in JPEG Baseline coding is developed. The method is based on a geometric interpretation of the DCT, and the calculated limits are as close as 14% to the maximum code-lengths. The proposed strategy can be adapted to other transform coding methods, e.g., MPEG 2 and 4 video compressions, to calculate close upper...

Several factors are considered in the development of embedded systems, among which may be mentioned: physical size, weight, mobility, power consumption, memory, safety, all combined with a low cost and ease of use. There are several techniques to optimize the execution time and power consumption in embedded systems. One such technique is the code compression, the majority of existing proposals ...

The class of k-bit delay decodable codes, source codes allowing decoding at most k bits for ≥ 0, can attain a shorter average codeword length than Huffman codes. This paper discusses the general properties with finite number code tables and proves two theorems which enable us to limit scope be considered when discussing optimal