U.S. Philips Corporation

Raymond G Schayes

Pol A Gustin

Ulf Rothgordt

Robert Bodart

Gerhard Renelt

Pieter Homan

Michel F Berck

It is known in the transmission of facsimile pictures to transmit the black-white data represented by one binary position per picture element via a run length coding. For the transmission of pictures in which the individual picture elements are represented by binary words having a plurality of binary positions, the individual binary positions of all the binary words are now always subjected picture line-sequentially to a run length coding and are transmitted. When a hierarchic code is used for the representation of P.E. values a compatability with the conventional facsimile receivers is simultaneously provided, which then processes only the most significant binary positions. In addition, measures for the preprocessing of the scanning values are described, so as to obtain a smoothed sequence which can more effectively be transmitted by means of run length coding.

Method of transmitting pictures and an arrangement for performing the

Facsimile transmission arrangement for documents which are divided into document lines and which contain photographs in addition to text. The text zones of a document line are subjected to a normal run-length coding. The photo zones are subjected to a photo coding. Therein, areas which have a uniform grey tone are first converted into a sequence of binary '0' and '1' elements which succeed each other in a regular alternation. Thereafter a first and a second code word are generated which indicate the number of binary '0' elements and the number of binary '1' elements, respectively of the sequence. These code words are transmitted to the receiver either directly or after having been converted into a Huffman code.

Facsimile transmission arrangement

A method of manufacturing an electrostatic write head comprises an insulating plate-shaped substrate having conductor tracks which extend as parallel conductor tracks in a strip-shaped region on the substrate. The substrate is divided into two plates along a dividing line which extends in the strip-shaped region, perpendicularly to the conductor strips. The two plates are subsequently joined so that their sides provided with conductor tracks face each other.

Method of manufacturing electrostatic write head

An electrostatic write head. An insulating plate-shaped substrate is provided with conductor tracks which extend as parallel conductor tracks in a strip-shaped region on the substrate. The substrate is divided into two plates according to a dividing line which extends in the strip-shaped region, perpendicularly to the conductor strips. The two plates are joined so that their sides provided with conductor tracks face each other.

Electrostatic write head

A facsimile circuit for a transmitter or a receiver, having an automatic switch-over between a photo and a text information signal processing. The more or less analog changing, photo information signal and the pulse-shaped changing, text information signal are converted into a binary signal suitable for supply to a reproduction device. A detection circuit, which performs a dual signal differentiation for detecting the presence of photo or text information controls a switch-over device through which the facsimile signal becomes available for transmission and/or reproduction after it has passed through an analog-binary or pulse-binary signal conversion circuit respectively.

Facsimile circuit

In facsimile transmission the sequences of picture elements having the same luminance are transmitted in coded form. The code words have, in general, different lengths and no ambiguous beginning or end marking respectively. Consequently, in case of a disturbance during the transmission not only the luminance values are generally falsified but also the plurality of successive picture elements so that in situ of the receipt picture lines appear which are too long or too short. In accordance with the invention it is now proposed in the case of a picture line which was received in a disturbed manner to compare it to one or both adjacent picture lines respectively, to take-over the portions having an adequate correlation, and, as regards the place of the disturbed portion to shift the end of the disturbed picture line in such a way that the definite line gets the prescribed length and to replace the portions of insufficient correlation by the corresponding information of one of the two adjacent picture lines. This comparison can be done relative to the two ends of the disturbed picture line. It is particularly favorable for the comparison that the picture elements of each picture line are grouped in equal groups and to check if the ratio of the number of, for example, black picture elements having a corresponding position in adjacent lines relative to the total number of black elements in the groups of the two lines together, remains below a given threshold value (decorrelation).

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Brussels, Belgium

Raymond G Schayes