A method and apparatus for generating a half-tone representation of an original image is described. The apparatus comprises an exposing beam generator (8); a record medium support (11); and a mirror (10) for causing an exposing beam generated by the beam generator (8) to scan a record medium mounted on the support (11). An exposing beam control system (5) generates a two state control signal (CS) to control the condition of the exposing beam, the control signal being generated in accordance with...

An image processing apparatus includes an input unit for inputting an image signal, a conversion unit for converting the image signal input from the input unit and outputting the converted image signal, and an output unit for outputting a pulse-width modulation signal based on the converted image signal output from the conversion unit. The output unit is operated in a fixed period processing mode regardless of an output characteristic of the pulse-width modulation signal, and outputs the pulse-w...

A number of kinds of gradation correction data is prepared beforehand, and when the type of a facsimile machine is specified, a host CPU selects among the gradation correction data some gradation correction data in accordance with the type of the facsimile machine. Then, the selected gradation correction data are written into the RAM to make a gradation correction table optimum for the type of the facsimile machine. When the gradation correction data are written into the RAM, addresses of these ...

An image processing apparatus for processing a half tone image comprises: an input device to input an image signal; an image forming circuit to form an image onto a recording medium such as a photosensitive drum on the basis of the image signal supplied by the input device; a generator to generate a plurality of image data having different densities; a density detector to detect a density of the image formed on the recording medium by the image forming circuit on the basis of the image data gene...

An electronic half-tone generating circuit for enabling a black and white facsimile transmission system to accurately and efficiently transmit and reproduce images including shades of grey as well as black and white and including an integrator responsive to a first data signal and operative to integrate the difference between an input analog signal and a first reference potential to develop a first integral signal commensurate therewith, and responsive to a second data signal and operative to in...

A multi-tone image processing method and apparatus in which mutually dissimilar tone levels are realized by changing the additive condition of recording energy by means of different recording positions, even when the number of recording operations within a specific range is identical. For example, in an electrophotographic apparatus, when the number of irradiation by a light spot within a specific range remains constant as the irradiation position is changed in the specific range, there is a cha...

Ink jet and xerographic binary graphic printers are disclosed which make reproductions by marking the pixels within a raster pattern on a copy sheet with a high or low density (e.g. black or white) mark in response to electrical printing signals. The printing signals are generated by comparing the magnitude of video signals representative of a continuous tone raster image with electrical screen signals organized into halftone cells according to a pattern. A shift circuit processes received video...

A method and apparatus for reproducing an original image includes a scanner or other image source for generating digitized raw image data for each pixel of an image. For each pixel, the raw image data is transformed into a rendering gray level value by comparing the raw image data value with threshold values from a threshold mask set. There are various threshold mask sets that may be used in accordance with a dot type that is selected based on a calculated local contrast index. The dot type bein...

A method and device for recognizing half-tone image information having a local frequency within predetermined limits such that an information area which may also contain other kinds of image information, is scanned line by line to generate a video signal or series of pixels which is subjected to a recognition process to determine, for each part of the signal, whether the same belongs to half-tone image information, wherein: the grey level maxima in the signal above a predetermined high threshold...

An image processing apparatus comprises a pulse-width-modulation signal generator for processing an image signal generated by an image signal generator by using a pattern signal to produce a pulse-width modulation signal. The pulse-width modulation signal generator generates first and second pattern signals of different periods, selects one of the pattern signals in accordance with a property of an image to be processed, and inhibits the generation of the non-selected pattern signal.