Ordering techniques for facsimile coding: A review

Netravali, Arun N.; Mounts, F. W.

doi:10.1109/proc.1980.11745

Cited by 25 publications

(6 citation statements)

References 6 publications

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“…This gives a better result than simple filtering would do, leading to improved sharpness and reduced risk of Moirt disturbance. Tests have been carried out on a representative halftone test image achieving compression rates of [16][17][18][19][20][21][22]. The image quality is preserved at normal viewing distance, though close examination reveals a slight degradation in sharpness and one slightly visible artifact.…”

Section: Discussionmentioning

confidence: 99%

Data compression of scanned halftone images

Forchhammer

Jensen

1994

IEEE Trans. Commun.

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Section: Discussionmentioning

confidence: 99%

Data compression of scanned halftone images

Forchhammer

Jensen

1994

IEEE Trans. Commun.

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“…This is the opposite conclusion* from that given in our earlier paper, which used a different source material. 1 For the pictures used in Ref. 1, we had found that ordering schemes with two sets of codes resulted in 10 to 18 percent higher entropies than the entropies obtainable with one set of codes.…”

Section: * This Algorithm Is Related To the One Proposed By Preu/i (Rmentioning

confidence: 92%

“…T h e predictor varies from picture to picture; however, the variation is not great, as shown in our earlier paper. 1 The predictor for a typical picture [ C C I T T picture 2 ( Fig. l b ) ] is shown in Table I.…”

Section: Prediction Algorithmmentioning

confidence: 99%

Some Extensions of the Ordering Techniques for Compression of Two-Level Facsimile Pictures

Mounts¹,

Netravali²,

Walsh³

1978

Bell System Technical Journal

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We present extensions of our earlier published ordering techniques for efficient coding of two-level (black and white) facsimile pictures. Ordering techniques use the two-dimensional correlation present in spatially close picture elements to change the relative order of trans mission of elements in a scan line so as to increase the average length of the runs of consecutive black or white elements in the ordered line, making the data more amenable to one-dimensional run-length coding. The extensions that we consider allow us to use different run-length codes to match the statistics of different parts of the ordered data, and to drop certain runs from transmission. Computer simulations using the eight standard CCITT pictures, which have a resolution of ap proximately 200 dots/inch, indicate that these extensions can result in transmission bit rates which are about 11 to 21 percent lower than the ordering schemes described in our earlier work. The entropies vary between 0.021 and 0.125 bits/pel for the eight pictures.

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“…i.e., where t > kT and k = 1;2;3111: (15) In general, T = 1 or 2 iterations is sufficient for most input data distributions. Note that when a new period starts, initial vitality of each node normally will not equal 1=M(0) as in the first period.…”

Section: B Redistribution Of Learning Ratesmentioning

confidence: 99%

Online learning vector quantization: a harmonic competition approach based on conservation network

Wang

Sun

1999

IEEE Trans. Syst., Man, Cybern. B

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Abstract-This paper presents a self-creating neural network in which a conservation principle is incorporated with the competitive learning algorithm to harmonize equi-probable and equi-distortion criteria [1]. Each node is associated with a measure of vitality which is updated after each input presentation. The total amount of vitality in the network at any time is 1, hence the name conservation. Competitive learning based on a vitality conservation principle is near-optimum, in the sense that problem of trapping in a local minimum is alleviated by adding perturbations to the learning rate during node generation processes. Combined with a procedure that redistributes the learning rate variables after generation and removal of nodes, the competitive conservation strategy provides a novel approach to the problem of harmonizing equi-error and equiprobable criteria. The training process is smooth and incremental, it not only achieves the biologically plausible learning property, but also facilitates systematic derivations for training parameters. Comparison studies on learning vector quantization involving stationary and nonstationary, structured and nonstructured inputs demonstrate that the proposed network outperforms other competitive networks in terms of quantization error, learning speed, and codeword search efficiency.

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Ordering techniques for facsimile coding: A review

Cited by 25 publications

References 6 publications

Data compression of scanned halftone images

Data compression of scanned halftone images

Some Extensions of the Ordering Techniques for Compression of Two-Level Facsimile Pictures

Online learning vector quantization: a harmonic competition approach based on conservation network

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