Matsushita Electric Industrial Co., Ltd.

Matsushita Graphic Communication Systems, Inc.

Matsushita Research Institute Tokyo, Inc.

Hiroaki Kotera

Yukifumi Tsuda

Hiroyoshi Tsuchiya

Kunio Yoshida

Yoshimitsu Kanno

Heijiro Hayami

Teruo Fumoto

Katsuhiro Kanamori

Motohiko Naka

Hidehiko Kawakami

Tsutomu Shibata

Toshiharu Kurosawa

Kunio Sannomiya

Ryuzo Kan

Hideto Motomura

Osamu Yamada

Shin Yamada

Akiyoshi Tanaka

Atsuharu Yamamoto

Katsuo Nakazato

Katsura Kawakami

Nobuyoshi Kihara

Shigeo Komizo

Mikio Fujita

Yoshihiro Uno

Shigeo Shimazaki

Toshihide Hane

Yuetsu Ochiai

Kazufumi Suzuki

Etsuko Hirokami

Hiroaki Miwa

Mutuo Hashizume

Hideaki Ohira

Rika Hashimoto

Kaoru Sasabe

Masao Takebe

Ryuzo Itabashi

Haruko Sugita

A color converting apparatus is provided with a table memory for storing pieces of color converting data defined in an output color space at color converting addresses, and a signal receiving section for receiving three signals designating an input color in a lightness-color difference space. The color converting addresses are placed at lattice points of cubic blocks formed by partitioning the lightness-color difference space in a lightness direction and first and second color difference directions. Each of the cubic blocks has the lattice points Pa, Pb, Pc and Pd at its lower plane and the lattice points Pe, Pf, Pg and Ph at its upper plane. Each of the cubic blocks is partitioned into a first triangular prism having the lattice points Pa, Pb, Pc, Pe, Pf and Pg and a second triangular prism having the lattice points Pa, Pd, Pc, Pe, Ph and Pg. A particular triangular prism in which the input color is included is specified, and six pieces of color converting data Da, Db (or Dd), Dc, De, Df (or Dh) and Dg addressed at the lattice points Pa, Pb (or Pd), Pc, Pe (or Ph), Pf of the particular triangular prism are read out from the table memory, and an output color which corresponds to the input color and is defined in the output space is interpolated with the color converting data read out.

Color converting apparatus for performing a three-dimensional color

A color value correction apparatus for converting each of successive combinations of input tricolor digital values into an output color value in accordance with predetermined data stored in memory, includes three table memories which store values which are respective differences between color values corresponding to vertices of unit tetrahedra in a color space and a reference color value that is common to all of a set of tetrahedra forming one of an array of unit cubes or parallelepipeds which constitute that color space, and also includes a table memory that stores these reference color values. To obtain an interpolated output value, each of these memories is addressed three-dimensionally by the high-order bits of an input tricolor value combination to thereby specify one of the unit cubes or parallelepipeds, and the difference value memories are in addition addressed by a value, derived from the low-order bits of the input value combination, specifying a specific tetrahedron containing the interpolation point. An interpolated output value can thereby be obtained by executing only three multiplication operations followed by addition operations.

Apparatus for correction of color signal values

A correspondence relation between a structure of a bi-level pattern A and a structure of a bi-level pattern B is statistically learned by use of a learning high-density image. The bi-level pattern A forms a partial region of a low-density character and line image except a screened dot image. The bi-level pattern B forms a corresponding partial region of a desired high-density image. A judgement is made as to whether the low-density image is equal to or different from a screened dot image. Reference pixels are selected from the partial region of the low-density image. The low-density bi-level pattern A is converted into the high-density bi-level pattern B on the basis of a result of the learning by use of the selected reference pixels when the low-density image is different from a screened dot image. A pixel of the low-density image is repeated to convert the low-density image into the high-density image when the low-density image is equal to a screend dot image.

Method and apparatus for converting a line density of a bi-level image

A color conversion apparatus is described whereby color within at least one specific region of a color picture can be converted to a different color in a reproduced picture, while enabling gradations of color and lightness within that region to be left substantially unchanged. The conversion is based upon setting of pre-calculated output values in a table memory within a color conversion section, by an initialization operation, and conversion can be a change in one color attribute or in a combination of attributes of respective color values within the selected region. The table memory subsequently responds to successive input color values supplied thereto by producing color-converted output values which can be supplied for example to a color printer apparatus, with resultant degrees of color change being determined in accordance with degrees of closeness of one attribute or a combination of attributes of each input color value to the corresponding attribute or combination of attributes of a predetermined color value.

Color conversion apparatus for altering color values within selected

A method of data display for a system which includes a main image memory having stored therein data representing a main image, a display memory coupled to temporarily hold data transferred thereto form the main image memory, and a display apparatus for displaying at least a selected portion of the data held in the display memory, whereby while scrolling is being executed in the horizontal or vertical display direction, new data are transferred from the main image memory to the display memory only when the limits of the data currently held in the display memory are exceeded, and with only data for one display line or column being transferred in such a case.

Method of image display with scrolling capability

An apparatus for receiving input data values representing an array of picture elements of a source image containing one or more bar code regions, whereby the input data values are converted to bi-level values representing black or white states which are stored in an image memory, while in addition the bi-level values are processed to obtain data representing an image in which a 'skeleton' central portion of the bar code region appears as an all-black region, while background black regions are eliminated. A central position and the slope of a central axis of the bar code region are computed based on that 'skeleton' region, and data values in the image memory which conform to the central axis are then read out, to read the bar code data.

Image signal processing apparatus for bar code image signal

A color correction method applicable to a digital processing type of color copier, whereby a set of color patches of respectively different sample colors is printed using a set of printing data values, the color patches are then scanned and analyzed to obtain color patch input data values by the color copier, and each of all of the possible input color data values that can be produced by the scanner/analyzer section of the color copier is then related to one of the color patch input data values which is closest thereto in a 3-dimensional color space. Each of these possible input color data values is thereby related to an appropriate color printing value, whereby a color correction table can be generated which provides correction accuracy that is independent of non-linearity of color printing characteristics.

Color correction method for color copier utilizing correction table

In a method and an apparatus for processing an image, a small screen dot pattern is prepared. A large screen dot pattern is generated by copying or repeatedly reading out the small screen dot pattern. Data of a variable tone image are processed with the large screen dot pattern and are thereby converted into processed image data representative of a screen dot image. The screen dot image may be recorded in a suitable way.

Method and apparatus for processing an image

Color correction method and processor for improving the quality of color reproduction in a color picture recording unit or display unit in a color copy machine, a color facsimile or a color printer. A memory means previously stores in a table values of secondary color correction image data used for recording corresponding to values of primary image data produced through a color scanning of a color picture. The secondary color correction image data are read out from the table by addressing signals formed from the three color components of the primary image data. Data bits for the addressing signals of the three color components of the primary image data are assigned unevenly depending on the contribution factor of each in forming the three color components of the secondary color crrection image data, thereby reducing the required number of addressing bits and associated memory.

Color correction processor with memory addressed by color component

An apparatus for expanding or contracting image data includes an input for storing the image data to be processed, a first barrel shifter for shifting the output data of the input register, a control register for storing a mapping pattern which indicates a position of the image data bits to be extracted in the expansion mode or which indicates the number of times when the image data are to be copied, an expansion and contraction circuit for expanding or contracting the image data by referring to the mapping pattern, and a second barrel register for shifting the output image data of the expansion and contraction circuit before the data are loaded in an output data register.

Image data expanding and/or contracting method and apparatus

A halftone signal having one of two discrete levels is generated for each print position along each print line by comparison between a gray scale value of an original with a threshold value stored in a memory. The memory has an .alpha.M.times..beta.N matrix array of cells each storing a particular threshold value, where M, N, .alpha. and .beta. are integers. The memory is divided into .alpha..times..beta. identical imaginary matrices of M.times.N elemental areas each containing a cell in a particular one of .alpha..times..beta. positions. The threshold values stored in each imaginary matrix have a prescribed ordered-dither distribution and those stored in positionally corresponding elemental areas have a dot-dispersive or a dot-concentrative distribution. The memory is addressed in a given direction in response to each print position and in a direction normal to the given direction in response to each print line to read a stored threshold value for each print position for comparison with the gray scale value.

Method and apparatus for generating pseudo-halftone dots by comparing

In a band compression method using an adaptive prediction system preferably applicable to facsimile transmission, a method of selecting picture elements to be referred (hereinafter defined as reference picture elements) for predicting an information value of a picture element wherein the reference picture elements are not selected uniformly and continuously from the neighborhood of the predicted picture element, but a group of picture elements (the first order picture elements) adjacent to the predicted picture element and further a group of picture elements of equal or higher order than the third order are selected as reference picture elements by excluding those shaded picture elements which lie on lines connecting the predicted picture element and the first order picture elements.

Method of band compression

A color image duplicating device comprises a function generator (60) for generating a plurality of functions of n degree wherein elements of color separated data (201, 202, 203) from a color original (1) are variable, a storing device (66) for storing predetermined coefficients, and an arithmetic unit (61, 62, 63) for performing the calculation to find the product and sum of outputs from the function generator (60) and that of the storing device (66). An output from the arithmetic unit (61, 62, 63) is applied to a color recorder (3) to form a color duplicated image.

Color image duplicating system

To overcome the tendency of the recording head of a dot printer to become inoperative in a range below a threshold level, a gray scale input signal is modulated with an oscillating signal so that the modulated signal oscillates above and below the threshold level to reproduce halftone values below the otherwise inoperative range.

Dot printer for reproduction of halftone images

Light beams scans patterns of a subject copy, being reflected therefrom, and being converted into pulsating electrical signals. Color borders between two different colored patterns are detected based on the pulsating signals. On the other hand, a color of a predetermined scanned line following each of the color borders is sensed for determining the sensed color as a color between the adjacent color borders.

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Hiroaki Kotera