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Topic: Entropy encoding

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	Information entropy - Wikipedia, the free encyclopedia
		Entropy is a measure of this randomness, suggested by Claude E. Shannon in his 1948 paper A Mathematical Theory of Communication.
		Entropy effectively bounds the performance of the strongest lossless (or nearly lossless) compression possible, which can be realized in theory by using the typical set or in practice using Huffman, Lempel-Ziv or arithmetic coding.
		Thus, the entropy of the source alphabet, with its given empiric probability distribution, is a number equal to the number (possibly fractional) of symbols of the "ideal alphabet", with an optimal probability distribution, necessary to encode for each symbol of the source alphabet.
	en.wikipedia.org /wiki/Entropy_(information_theory) (1613 words)

	Entropy encoding - Wikipedia, the free encyclopedia
		An entropy encoding is a coding scheme that assigns codes to symbols so as to match code lengths with the probabilities of the symbols.
		Typically, entropy encoders are used to compress data by replacing symbols represented by equal-length codes with symbols represented by codes proportional to the negative logarithm of the probability.
		If the approximate entropy characteristics of a data stream are known in advance (especially for signal compression), a simpler static code such as unary coding, Elias gamma coding, Fibonacci coding, Golomb coding, or Rice coding may be useful.
	en.wikipedia.org /wiki/Entropy_encoding (228 words)

	Talk:Entropy encoding - Wikipedia, the free encyclopedia
		Entropy encoding is encoding where each symbol is assigned a pattern whose length/cost corresponds to its entropy (hence the name).
		Well, the JPEG standard defines "entropy encoding" as "A lossless procedure which converts a sequence of input symbols into a sequence of bits such that the average number of bits per symbol approaches the entropy of the input symbols", a description which does not apply to dictionary coding.
		Entropy is the expected value of the negative log of the probability, not the actual value of the negative log of the probability associated with a particular symbol's value.
	www.wikipedia.org /wiki/Talk:Entropy_encoding (1488 words)

	Encyclopedia: Entropy encoding (Site not responding. Last check: 2007-11-07)
		Typically, entropy encoders are used to compress data by replacing symbols represented by equal-length codes with symbols represented by codes proportional to the negative logarithm logarithm is a function that gives the exponent in the equation b
		Three of the most common entropy encoding techniques are Huffman coding In computer science, Huffman coding is an entropy encoding algorithm used for lossless data compression.
		The term refers to the use of a variable-length code table for encoding a source symbol (such as a character in a file) where the variable-length code table has been derived in a particular way based on the estimated probability of occurrence for each possible value of the source symbol.
	www.nationmaster.com /encyclopedia/Entropy-encoding (908 words)

	Signal encoding and decoding system and method - Patent 6680975 (Site not responding. Last check: 2007-11-07)
		The decoder according to claim 19, wherein the entropy encoded data, the pattern signal and the additional information are multiplexed together as part of the coded data signal, and wherein said decoder further includes a demultiplexer which demultiplexes the entropy encoded data, the pattern signal and the additional information.
		The decoder according to claim 26, wherein the entropy encoded data and the pattern signal are multiplexed together as part of the coded data signal, and wherein said decoder further includes a demultiplexing means for demultiplexing the entropy encoded data, the pattern signal and the additional information.
		The decoding apparatus according to claim 34, wherein the entropy encoded data, the pattern signal and the additional information are multiplexed together as part of the coded data signal and wherein said decoding apparatus further includes a demultiplexer which demultiplexes the entropy encoded data, the pattern signal and the additional information.
	www.freepatentsonline.com /6680975.html?highlight=teletext (4631 words)

	esp@cenet description view
		In the aforesaid entropy encoding system, a code consisting of a small number of bits (for example, the Huffman code) is assigned to signals exhibiting high appearance probability among the signals of various values which arise, and a code consisting of a comparatively large number of bits is assigned to signals exhibiting low appearance probability.
		Specifically, in order to efficiently compress, for example, image signals by entropy encoding, it is necessary to create an optimal encoding table on the basis of a statistical analysis of each image and to carry out signal compression by use of the created table.
		The aforesaid entropy encoding system is thus desired to be improved particularly when it is necessary to process and store large numbers of images.
	v3.espacenet.com /textdes?&DB=EPODOC&IDX=EP128764 (1458 words)

	eEdition JJS :: Technical Article
		However, this type of entropy must be measured with the objective over time in mind, also recognizing that an up-front investment is made with the expectation of a long-term payoff.
		Since this is the additive inverse sense of the entropy (greater entropy is less valuable), the conversion from inputs to outputs requires intermediate representations for the possibilistic entities.
		This corresponds to an entropy metric of one.
	www.system-safety.org /~journal/eJSSv41n4/techarticle2_page2.html (2013 words)

	[No title] (Site not responding. Last check: 2007-11-07)
		During encoding, an input signal is typically pre-processed, sampled, converted, compressed or otherwise manipulated into a form for transmission or storage.
		The objective of entropy coding is to take advantage of such data correlation and minimize the average length of the code words among expected inputs having certain highly probable inputs.
		Preferred implementations overcome the resource requirements of large dimension vector encoding, and the inapplicability of coding into words of equal lengths, by providing an entropy based variable-to-variable code, where variable length code words are used to encode variable length X sequences.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/36751.000622&ELEMENT_SET=DECL (5612 words)

	Entropy encoding with a reduced memory size of code table - Patent 5673043 (Site not responding. Last check: 2007-11-07)
		More particularly, the present invention relates to an encoder for use in image processors for encoding digital image data by an entropy encoding process, wherein the data size of a code table, which is referred to at the time of entropy encoding, is substantially reduced.
		The encoded data are supplied either from the RAM 109 or from the IC card 110 to an entropy decoder 111 via the interface circuit 108, wherein the entropy decoder 111 decodes the data supplied thereto by referring to the loop up table 107.
		Thereby, the entropy decoder 111 restores the original coefficient data of discrete cosine transform as an output, and the output of the entropy decoder 111 thus obtained is then supplied to a quantization circuit 112 for quantization and further therefrom to an inverse discrete cosine transform unit 113 for inverse discrete cosine transformation.
	www.freepatentsonline.com /5673043.html (5423 words)

	Search Encyclopedia.com (Site not responding. Last check: 2007-11-07)
		entropy entropyĕn´trepē, quantity specifying the amount of disorder or randomness in a system bearing energy or information.
		Originally defined in thermodynamics in terms of heat and temperature, entropy indicates the degree to which a given quantity of thermal energy is available for doing useful work—the greater the entropy...
		As originally developed for audio systems, the sound signal is sampled at a rate of 44,100 times a second, then each sample is measured and digitally encoded on the 43/4 in (12 cm) disc as a series of microscopic pits on an otherwise polishe...
	www.encyclopedia.com /searchpool.asp?target=Entropy+encoding (597 words)

	Entropy Coding (EC)
		The process of entropy coding (EC) can be split in two parts: modeling and coding.
		Entropy coding can be done with a coding scheme, which uses a discrete number of bits for each symbol, for example Huffman coding, or with a coding scheme, which uses a discrete number of bits for several symbols.
		Range encoding was first proposed by this paper from G. Martin in 1979, which describes the algorithm not very clearly.
	www.data-compression.info /Algorithms/EC (1429 words)

	United States Patent Application: 0040101205
		A method for coding uncompressed data, the method comprising: defining a context based upon a position of a most significant bit in the uncompressed data and a context value; encoding the context to generate an encoded context; and compiling the uncompressed data based on the encoded context and remaining bits of the uncompressed data.
		In an embodiment, the decoded data is passed to a position decoding block (not shown), which performs the decoding of the context based on the context value and the position of the most significant bit.
		The context is encoded and combined with the RAW to generate the coded bit stream.
	appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=dhavala.IN.&OS=IN/dhavala&RS=IN/dhavala (4036 words)

	Encoding
		Simply adding bits to a gamma encoding does not result in a good distribution of steps, because we can no longer assume that the viewer is adapted to a particular luminance level, and the relative quantization error tends towards infinity as the luminance tends towards zero.
		One of the first groups to arrive at a standard for HDR image encoding was the Computer Graphics Division of Lucasfilm, which branched off in the mid-80’s to become Pixar.
		Although the basic encoding is 48 bits/pixel as opposed to 32 for the LogLuv and RGBE formats, the additional precision is valuable when applying multiple blends and other operations where errors might accumulate.
	www.anyhere.com /gward/hdrenc/hdr_encodings.html (6879 words)

	DVP contribution (Site not responding. Last check: 2007-11-07)
		The additional functionality introduced by grouping of encoded fields or frames as well as the mechanism for controlling picture quality and bitrate, which is necessary in order to define an upper limit for the performance of a server or a transmission link located downstream, is not defined by any common standard.
		For encoding of the DC coefficient, only the difference between the actual DC value and the DC value of the spatially preceeding block is encoded (DPCM), thus again establishing a probability distribution which is well suited for the following entropy encoding step.
		The final entropy coding stage assigns codes of different length to the events to be encoded by taking into account their probability.
	viswiz.gmd.de /DVP/Public/deliv/deliv.211/m_jpeg/irt_jpeg.htm (1465 words)

	Unit - 2 Data Encoding
		Data encoding as used in this chapter means representing the data with less number of bit than the original by exploiting the redundancy in it.
		We can use entropy, source, and hybrid encoding techniques to compress image and video data used in the multimedia applications.
		It has also be noted that encoding and compression shall be used interchangibly in this chapter.
	www.ii.metu.edu.tr /~ion514/MASTER/lectures/Chapter4/42.html (333 words)

	Adaptive probability estimator for entropy encoding/decoding - Patent 5025258 (Site not responding. Last check: 2007-11-07)
		It is known that entropy, e.g., arithmetic, encoding and decoding requires a probability estimate of the symbol to be encoded and subsequently decoded.
		Entropy decoder 103, also including aspects of the invention, interfaces to the transmission media to obtain the receiver data stream and decodes it into replicas of the transmitted symbols s(k).
		By way of example, and not to be construed as limiting the scope of the invention, for an image compression system, symbol s(k) is representative of the color of a current pixel to be encoded and the context c(k) may be determined by the colors of prescribed prior pixels.
	www.freepatentsonline.com /5025258.html (4242 words)

	CSE 126 Multimedia Systems
		Two classes of encoding techniques are Source Encoding and Entropy Encoding.
		Source encoding is lossy and applies techniques based upon properties of the media.
		Entropy Encoding techniques are lossless techniques which tend to be simpler than source encoding techniques.
	www-cse.ucsd.edu /classes/su03/cse126/lecture4.htm (702 words)

	A JPEG2000 Primer (Site not responding. Last check: 2007-11-07)
		In the Elias entropy code, a positive integer x is represented by 1 + floor(log(2) x) in unary, followed by the binary representation of x without its most significant bit.
		This means that it is not necessary to transmit the entropy coding table with the compressed file.
		Again, since the image is broken up into sub-bands and tiles, we can apply the entropy encoding to every tile in parallel.
	www.gvsu.edu /math/wavelets/student_work/Miljour/entropy.html (199 words)

	Lossless Compression (Site not responding. Last check: 2007-11-07)
		Lossless compression is generally required in fields such as medical imaging and digital editing, where image quality is of paramount importance.
		A simple approach to coding a pair of stereo images together is to jointly encode the corresponding pairs of pixels using an optimal entropy code.
		This is also equivalent to jointly coding the left image pixel and the difference between the right and left image pixels.
	www.stanford.edu /~mbax/ee392c/node10.html (103 words)

	Joint entropy (Site not responding. Last check: 2007-11-07)
		The joint entropy measures how much entropy (information theory) is contained in a joint system of two random variables.
		The joint entropy is always at least equal to the entropies of the original system, adding a new system can never reduce the available uncertainty.
		The joint entropy is used in the definitions of the conditional entropy:
	read-and-go.hopto.org /Information-theory/Joint-entropy.html (282 words)

	JPEG Baseline Compression
		Since the DC coefficients are usually highly correlated, this reduces the entropy of the DC data stream (within the class of images usually seen, in any pixel ordering).
		The result is a series of numbers, e.g., 1,2,-1,0,2,3,-3,..., one number for each tile in the image, which is to be compressed with a lossless entropy encoding method.
		In the third column of numbers, the first unsigned binary number can be seen to be a 4 bit PCM code for the minimum number of bits required to transmit all potential values of the second signed 12 bit binary number.
	dakx.com /theory/jpegbaseline.html (1273 words)

	United States Patent Application: 0060009867
		The source ASVD modem 1312 combines the data stream 1316 and the audio stream 1310, encodes the combined data in digital form, and communicates the encoded data through the communications medium 1318 to a recipient ASVD modem 1320 at location 1304.
		However, the system 1300 requires that each participant at a separate location have the required ASVD modem hardware to interpret the encoded, digital data from the source location.
		The encoded, digital data communicated via the communications medium 1318 cannot be interpreted without a recipient ASVD modem 1320 to decode the received data.
	appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtml/PTO/search-adv.html&r=1&f=G&l=50&d=PG01&p=1&S1=Malvar.IN.&OS=IN/(Malvar)&RS=IN/Malvar (9065 words)

	Entropy encoding - Encyclopedia, History, Geography and Biography
		Entropy encoding - Encyclopedia, History, Geography and Biography
		Three of the most common entropy encoding techniques are Huffman coding, range encoding, and arithmetic encoding.If the approximate entropy characteristics of a data stream are known in advance (especially for signal compression), a simpler static code such as unary coding, Elias gamma coding, Fibonacci coding, Golomb coding, or Rice coding may be useful.
		Entropy encoding, See also, Lossless compression algorithms and Entropy.
	www.arikah.com /encyclopedia/Entropy_coded (217 words)

	Entropy Encoding (Site not responding. Last check: 2007-11-07)
		Each DC component is encoded by a VLC representing the number of significant bits in the DC term followed by a VLI representing the value itself.
		The VLC is coded by first determining the number of significant bits, SSSS, in the differential DC coefficient.
		To be complete, one must note that the first column is used for codes containing control functions and that in the baseline proces the complete table must not be defined.
	www.cs.kuleuven.ac.be /cwis/education/multimedia/94-95/Jpeg_And_Gif/entropy.html (410 words)

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