Konishiroku Photo Industry Co., Ltd.

Matsushita Electric Industrial Co., Ltd.

Konica Corporation

Seiichiro Hiratsuka

Satoshi Haneda

Hisashi Shoji

Masahiko Matsunawa

Koji Washio

Takashi Hasebe

Tetsuya Niitsuma

Tadao Kishimoto

Masaaki Kobayashi

Yoshinori Abe

Hiroshi Tokunaga

Kazuyoshi Tanaka

Yukihiro Nishida

Hiroshi Yamaguchi

Hiroyuki Yamamoto

Masahiko Itaya

Yukio Okamoto

Nagaaki Ohyama

Jun Yokobori

Hiroyuki Maruyama

Hiroshi Fuma

Toshio Honda

Kunihisa Yoshino

Akihiko Tamura

Yuuji Toyomura

Junpei Tsujiuchi

Toshifumi Isobe

Masaya Shimada

Kazushi Hayakawa

Yuji Toyomura

Hiroyuki Morimatsu

Takashi Kitada

Shinobu Soma

Yoshitsugu Hayashi

Takunori Tsuji

Takanobu Kajikawa

Etsuko Satoh

Etsuko Himoto

Keiichi Nakashima

Noriko Takeuchi

Mutsuaki Noma

Tadaomi Asou

Tetsuo Tanaka

A three-dimensional space formed by three-channel input signals is divided into a plurality of polyhedrons having vertices at points corresponding to a conversion table. A particular polyhedron is determined which is associated with the points corresponding to the three-channel input signals. The nonlinear interpolation is carried out using the conversion data corresponding to the vertices of the intended polyhedron thus determined and the conversion data corresponding to the vertices of the polyhedrons in surface contact with the intended polyhedron.

Method and apparatus for three-dimensional signal conversion

An image processor includes: a color conversion unit for converting an input signal to color signals of at least four colors; a gamma correction unit for performing gamma correction on the color signals; a binarization unit for binarizing the color signals through comparison with a threshold value; a superimposing unit for superimposing a color signal of at least one color but of the binarized color signals on another color signal to convert the signals to a superimposed color signal; logical operation unit for performing a logical operation previously defined for an image of three or fewer colors on the superimposed color signal; and a separator for separating color signals as an output of the logical operation unit into separated color signals of at least four colors.

Image processor

A continuous-tone image data is converted to a bi-level image data by halftoning conversion, then the bi-level image data i.e. binary image data is compressed by compressing means including predictive coding and image data compressing. These operations are done in a image coding apparatus. In this apparatus, when the continuous-tone image is converted into bi-level image data in halftoning so that predictions of predictive coding become strong. As a result, halftoning conversion is performed within a scope of binary image-coding-rules. This permits to produce a binary data easy to compress. Compressing a binary data in a low distortion quality and at a high compression rate is achievable through a method of image coding, and by an image coding apparatus of the present invention. Also a recording medium including a program carrying out this method is obtainable.

Method of image coding, image coding apparatus, and recording medium including image coding program

A binary image encoding method includes a predicting step of predicting a binary image, and a blocking step of blocking a data sequence, which indicates the prediction hit or miss in the predicting step, into blocks to produce blocked data. Also, a binary image encoding method includes an encoding step of switching a Huffman table in accordance with the blocked data around a Huffman-block-encoding-target block to apply the Huffman block encoding to the encoding-target block.

Image encoding method and apparatus

Still color image data is separated into plural planes, and pixels of each plane are processed predictive coding within plane and/or between planes, and the predictive error data is modified by using the correlation of predictive errors within plane and/or between planes, and the modified data is coded by entropy coding so as to curtail the quantity of data, thereby realizing high speed and efficient predictive coding.

Reversible coding method, reversible coding apparatus, and memory medium used therein

A method of gradation reproduction including (a) taking image data of a pixel subject to transaction as observing pixel data; (b) weighting the image data with an error diffusion matrix based on an error data calculated on a previously processed neighboring pixel of the observing pixel; (c) obtaining a data of pixel neighboring the observing pixel; (d) calculating a density gradient around the observing pixel from the weighted observing pixel data and the neighboring pixel data, and determining whether or not the pixel lies in an image edge region; (e) determining a dot size by comparing the weighted observing pixel data with a threshold value corresponding to an individual dot size, and selecting a predetermined smaller dot size if the weighted observing pixel data lies in the edge region; (f) producing an output of dot data by taking dot coordinates as a standard position of the observing pixel, if the dot size data is greater than a threshold value for coordinates determination after a comparison between them; and (g) calculating an error data from the observing pixel data, the dot size data and the dot coordinates, and storing it in a storage means for use in a transaction of the succeeding pixel. Repeating the foregoing transaction controls both the dot size and dot coordinates, to realize a method of gradation reproduction that can prevent moire and texture from merging, and maintain fine transaction in the edge region.

Method of gradation reproduction

In a method for color adjustment of a color image, a color adjustment software window is displayed and color image data on an RGB color space before color adjustment is displayed on a before-adjustment image window of a color monitor screen. An operator for color adjustment designates a color on the before-adjustment image window (or a designated color) and sets an adjustment color for the designated color (or a designated adjustment color). The designated adjustment color is set from a color pallet or by changing the R, G and B levels of a designated-color window and color adjustment parameters for the designated color are determined from the designated color and the designated adjustment color. In performing the color adjustment of a color other than the designated color (or an interpolated color), color adjustment parameters for the interpolated color are calculated on the basis of a distance between the interpolated color and the designated color on a color space to obtain the interpolated color after color adjustment which is to be displayed on an after-adjustment image window.

Color adjustment method for pixels of color images that designates color

An image with multiple gradations is divided into a plurality of pixel blocks each of which comprises a plurality of pixels. Pixel data of the pixel block are compressed to two representing values indicative of pixel levels and a binary block pattern by block approximation coding. Representing patterns of which the number is less than that of the block patterns are set previously. A plurality of block patterns having a specific relationship with one of the representing patterns are replaced with the one of the representing patterns, so that the block patterns are compressed.

Image compression method

An image compression method for encoding gradation image data for use in, for example, a printer or a copying machine handling the gradation image. When a difference between two representative values in one block E)f the image data is less than a predetermined amount, a block code made up of a single piece of gradation data and one pixel array pattern is generated. When the difference is not less than the predetermined amount, the representative values are replaced by any of sixteen substitute values, and a block code is formed to include two gray scale data each of four bits and a single pixel array pattern, thereby realizing coding compression of the image information.

A color image processor that corrects a color image signal for the disagreement of images caused by the vibration of the image sensor when scanning a manuscript. The image sensor delivers an image signal that includes three signals, each one representing the level of brightness of one of the primary colors contained on the scanned image. Each signal includes a discrete value for each pixel reading the sensor and hence, comprises the brightness levels for a plurality of pixels. One of the three signals is called a standard color signal; the other two are called non-standard color signals. Each of the brightness levels of a non-standard color signal is sequentially stored in a register array. Individual levels of the pixels in the register array are examined to determine whether a pixel exists at an edge portion of a letter image. A pixel that exists at an edge portion is called a correction objective pixel. Various detectors connected to the register array are used to determine whether a pixel is a correction objective pixel. If a pixel is determined to be a correction objective pixel, the levels of brightness of neighboring pixels together with the level of brightness of the standard color pixel corresponding to the correction objective pixel are used to calculate a correction factor, which factor is used to adjust the level of brightness of the correction objective pixel. By adjusting the value of the level of brightness of the correction objective pixel of the non-standard color pixels the image signal is corrected for unwanted movements of the image sensor.

Color image processing apparatus

In a color separating device, three reflection elements each formed by laminating a dichroic mirror and a total reflection mirror via a transparent layer interposed therebetween are used. The three reflection elements have mutually different spectral characteristics and are arranged to separate incident light reflected from a color original into three color lights without causing a difference in optical paths of the respective color lights. Two of the reflection elements may be used in combination with a condenser lens having principal points whose positions differ depending on wavelengths of light, so as to perform the three-color separation in a similar manner.

Color separating device and color image reading device incorporating same

An image processing apparatus for converting red, green, and blue luminance signals into cyan, magenta, and yellow density signals comprises: a first signal processing circuit for producing the cyan density signal from the red luminance signal; a second signal processing circuit for producing the magenta density signal from the green luminance signal and the cyan density signal; and a third signal processing circuit for producing the yellow density signal from the blue luminance signal, the cyan signal, and the magenta signal. Each of signal processing circuits comprises one or more look-up tables. The table of the second signal processing circuit may include the function of the first signal processing circuit and is supplied with red and green luminance signals. The third signal processing circuit has first and second tables. The first table responds to the cyan density signal and the blue luminance signal. The second table responds to the magenta density signal and the result of the first table. An image formation apparatus including the image signal processing apparatus mentioned above is disclosed also.

Image signal processing apparatus and image formation apparatus

An image processing apparatus for processing a digital color signal, given from outside the image processing apparatus, into a digital color recording signal, comprising; a color code generator for generating a color code signal representing a color of a digital pixel image signal, and a color reproduction unit for generating a color recording signal by processing another digital pixel image signal, in which these two digital pixel image signals are processed separately.

Color image processing apparatus capable of discriminating between a

An image formation apparatus for performing a gradation recording by changing a size of a dot on the basis of an image data inputted to the apparatus. The apparatus divides an image into a plurality of blocks each comprising a predetermined number of pixels and gives a preferential order with respect to a position within each of the plurality of divided blocks. When the preferential order is higher, the size of the corresponding dot is first enlarged on the basis of a density of the image data. This arrangement can prevent generation of a texture and deterioration of the image resolution irrespective of the case that characters or line drawings are mixed with half-tone pictures in the image.

Halftone image forming apparatus including density based dot enlargement

An image processing system provided with a reception device for receiving image information and an output device for outputting image information at high resolution in case where the received image information is binary image information, and for outputting image information at resolution lower than resolution of the received image data in case where the received image information is other than binary image data. Thereby, a quantity of image information can be reduced without degradation of picture quality. Thus an image can be transmitted and stored.

Image processing separately processing two-density-level image data and

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Kitakyushu, Japan

Seiichiro Hiratsuka