Fujitsu Corporation

Fuji Xerox Co., Ltd.

Toshiba Lighting & Technology Corporation

Kazuhiko Sato

Hiromitsu Horie

Hiroshi Oshio

Takao Kamata

Masaki Nose

Jun Moroo

Shigeru Ainai

Toshio Konaka

Koji Takahashi

Hirotaka Chiba

Yosuke Saito

Hirokazu Otake

Masahiro Mori

Shigemi Nagata

Shinichiro Matsumoto

Masatoshi Kumagai

Hiroshi Terasaka

Kenji Sakai

Tomohisa Mikami

Hiromichi Nakajima

Shigeyoshi Nakamura

Kiyoteru Kosa

Hideo Kozuka

Hiroyuki Kudo

Eiji Sasaki

A power supply device includes a control circuit and a first circuit. The control circuit switches between a current control mode and a voltage control mode according to an inputted dimming signal and thus dims a light-emitting element. In the current control mode the control circuit controls an output current supplied to the light-emitting element to a target current, and in the voltage control mode the control circuit controls an output voltage supplied to the light-emitting element to a target voltage. The first circuit detects the output current and the output voltage, and sets the target voltage at which switching between the current control mode and the voltage control mode is carried out as a first voltage.

Power supply device and luminaire

The present invention relates to an image processing method using the error diffusion method to prevent jumps in a highlight part and darkening in a shadow part at high resolution. The image processing method comprises a step of calculating an average value of density values of N&#xd7;M (N, M&#x3e;1) pixels, a step of adding the average value and a diffused quantization error value, a step of quantizing the addition result with a predetermined number of tones, a step of selecting a quantization pattern corresponding to the quantization result, and a step of calculating the diffused quantization error value from the quantization error. The error diffusion algorithm has flexibility in outputting dots. In other words, error diffusion processing is performed in N&#xd7;M pixel units, and a plurality of quantization patterns are provided, and a quantization pattern is selected based on the quantization result. Therefore jumps in a highlight part and smears in a shadow part can be prevented, the tone maintenance characteristic unique to the error diffusion can be satisfied, and a smooth and sharp image can be obtained.

Image processing method, and image processor and storage medium thereof

The present invention relates to an image processing method, an image processing apparatus and a recording medium that convert a grey scale image into an area gradation image. The present invention intends to provide an image processing method, an image processing apparatus and a recording medium capable of increasing processing speed in a state where high image quality is maintained. In the image processing method and the image processing apparatus according to the present invention, image data of a C component and image data of an M component in grey scale image data are converted into halftone image data in accordance with an error diffusion method, and image data of a Y component are converted into halftone image data in accordance with a blue noise mask method.

Image processing method, image processing apparatus and recording medium

An image reproducing apparatus, that outputs and reproduces an image having a greater number of gradation levels than that of input image data, is comprised of a buffer memory that accumulates input image data for a plurality of lines; an image data storing unit that extracts and stores image data of region of a predetermined size from the buffer memory; a specified portion detecting unit that detects a specified portion in which gradation of image data varies slowly from the predetermined region of stored image data; and an intermediate density data generating unit that generates, based on a result of detection by the specified portion detecting unit, intermediate density data composed with step smaller than the minimum value of a step between different gradation levels of image data. In the above apparatus, an image having a greater number of gradation levels than that of image data is output based on the intermediate density data. On the other hand, an image reproducing method executed by the above-described image reproducing apparatus or the like, is disclosed.

Image reproducing apparatus, image reproducing method, and computer readable storage medium

An image correcting method and apparatus is disclosed in which processing other than a smoothing process can be performed in accordance with conditions of a line such as correction of a line width with a small circuit size and at low cost. The disclosed dot image correcting method stores correction data corresponding to a correction dot pattern(s) in a window(s), determines whether or not a dot pattern coincides with a correction dot pattern, and when coincidence is detected, performs correction in accordance with corresponding correction data, characterized in that there are a plurality of windows, and correction data are stored corresponding to a combination of correction dot patterns in various windows, and determination is made as to whether or not dot patterns in a plurality of windows coincide with a combination of correction dot patterns in various windows, and when coincidence is detected, correction is performed in accordance with corresponding correction data.

Image correction method and image correcting apparatus

A method of representing a half-tone level with dot sets each comprised of contiguous dots including the steps of providing a dot-set center at an offset point that is neither a center of a dot nor a midpoint between centers of dots, selecting dots that are included inside a symmetric-shape area having a center thereof at the dot-set center, an area size of the symmetric-shape area being commensurate with an input image level, and representing a half-tone level corresponding to the input image level by forming a dot set comprised of the selected dots.

Image processing method and device for half-tone representation

An image forming apparatus in which a character/line drawing emphasizing section previously stores a correlation between diameter of dots and position of remarked dots to be varied (including movement of a dot position) for each dot pattern in a table, detects a dot pattern matching a dot pattern based on dot image data inputted by a pattern detecting section, and varies and corrects (including movement of a dot position) the diameter of a dot corresponding to a position of a remarked dot in the dot pattern.

Image forming apparatus

An image processing apparatus includes a threshold value processing circuit subjecting a correction value with respect to an input image data to a threshold value process and outputting an output image data, a subtracting circuit outputting an error signal based on a difference between the correction value and the output image data, an error filter distributing, as a distributing error data dependent on a value of a diffusion matrix, the error signal to neighborhood pixels of a target pixel within the input image data, and a correction circuit multiplying a coefficient to the input image data or the output image data.

Image processing apparatus

An image forming apparatus, such as a laser printer, ink jet printer, or a thermal transfer, which comprises a neural network. The apparatus improves image quality by reducing a zigzag included, e.g., in input image data, reducing the circuit size by reducing the number of bits having small weights for an input combination, and concurrently correcting the size of center, left and right picture elements in a predetermined window. The neural network outputs correction data for the size and position of the center dot in a window in response to an input of dot image data in a window or subdot pattern exposure data for the center dot. Additionally, the neural network uses any of the three values, +1, -1 and 0, for the coefficient of input combination for a hidden layer neuron, e.g., after a teacher pattern is learned. Further, the neural network outputs correction data for 3.times.N subblocks of picture elements obtained by dividing blocks of picture elements in the center, left and right of a window.

A method of achieving halftone representation of image data by using a printer for printing the image data includes the steps of providing a plurality of tone curves which takes into consideration characteristics of the printer, and selecting a tone curve from the plurality of tone curves. The method further includes a step of printing the image data by using the selected tone curve.

Halftone representation taking into account characteristics of image and

An image forming apparatus includes a photosensitive drum, an intermediate transfer drum, a divisional image forming system for forming image segments into which an image to be formed is divided on the intermediate transfer drum one by one, a sheet feeding mechanism for feeding a recording sheet, and a transfer device for transferring an image segment from the intermediate transfer drum to a recording sheet fed by the sheet feeding mechanism every time the image segment is formed on the intermediate transfer drum. A control unit for controlling the sheet feeding mechanism and the transfer device is also provided so that the image segments formed by the divisional image forming system are successively transferred from the intermediate transfer drum to the recording sheet so as to be continuous with each other.

Growing community of inventors

Kawasaki, Japan

Kazuhiko Sato