Abstract: The background compensation circuit defines a background threshold signal in dependence on an average value between the positive-peak and negative-peak signals previously received from the elements for scanning the pixels of the image, and in dependence on the analog signal (AS) of the pixel added to a reference signal. The circuit comprises two detectors (21, 22) for respectively detecting a positive peak and a negative peak and which each have a short charge time constant and a long discharge time constant. A summing circuit (25) generates a threshold signal (V.sub.s) as a linear combination of the signals (V.sub.max, V.sub.min) of the detectors (21, 22) the analog signal (AS) of the pixel and a reference signal (V.sub.r). Finally the threshold signal is compared (26) to the analog signal (AS) of the pixel to produce a binary reading signal which is at "one" level when the threshold signal is greater than the analog signal and is at "zero" level when the threshold signal is less than the analog signal.

Abstract: The apparatus for reading and digital processing of color images comprises groups of CCD sensing elements for reading the individual pixels forming the image. Each group of the sensing elements is associated with one primary color, for generating corresponding reading signals, which control a color indication circuit generating a color indicatory signal for indicating the presence of any color in the image. The colour indicator signal is derived from a table of zones of colours which is recorded in a ROM and can be addressed by the reading signals of the various colours, input from corresponding reading elements via compensation circuits. The colour signal is capable of controlling second selective scanning of document for recording the reading signals for all the primary colours of the image. The ROM is also capable of providing an indication of the mixture of colours of each pixel, which is compared to a predetermined mask for the purposes of suppressing a particular mixture of colours from the recording.

Abstract: A device for reading graphic symbols impressed on a sheet, comprising light sources for illuminating the sheet, an optical reading system and an array of photo-electric sensors for generating electrical reading signals. The device is compact in structure and of small dimensions, so as to allow it to be mounted upon the head-carrying carriage of a printing machine or typewriter. The device makes it possible to create, in a particularly simple form, reading apparatus for facsimiles or for optical character recognition (OCR) reading apparatus for memorizing signatures, graphical symbols and drawings or mathematical symbols, or apparatus for copying documents.

Abstract: The method enables images recorded with different definitions to be printed by the same printer, and the information to be printed with maximum print definitions. For this purpose, the print definitions (dots per mm) is a common multiple of the possible recording definitions. The information to be printed is extracted from a signal generator with a frequency corresponding to the recording definition, and is repeated in accordance with the multiple. For example with a print definition of 24 dots/mm defined by a row and column grid L1, L2, etc., C1, C2, etc., a character definition of 8 dots/mm is obtained by printing each dot three times in each row and repeating each row a further two times. The printer, which is therefor suitable for various purposes, for example as a word processor printer and as a facsimile printer, repeatedly prints each dot, along the horizontal and/or along the vertical, for a number of times corresponding to the multiple, to provide a line continuity and an improved image resolution.