Ricoh Company, Ltd.

Shiro Kofuji

Nobuyuki Sato

Naoyuki Urata

Takeshi Shibuya

Hitoshi Tamura

Hiroyuki Hitachi Inform Techn Co Ltd Abiru

Toshiyuki Hitachi Inform Techn Co Ltd Yamada

A halftoning device that converts an input pixel signal of 8 bits per pixel into an output pixel signal of r bits per pixel(r&#x3c;8), the halftoning device includes: a gradation correction unit that expands the input pixel signal into an expanded pixel signal of n bits per pixel(n&#x3e;8); a threshold value array storage that stores a threshold value array having a threshold value of 8 bits; and a threshold value expansion unit that expands the threshold value of 8 bits to expanded threshold value of n bits per pixel. A range of the expanded pixel signal output from the gradation correction unit is matched with a range of the expanded threshold value. The output pixel signal is set according to a comparison of the expanded pixel signal with the expanded threshold value corresponding to the threshold value that is selected for each input pixel signal.

Halftoning device and halftoning method and laser printer including the same

An image processing apparatus for compressing and decompressing image data is disclosed that is capable of image processing with a small memory area. The image processing apparatus includes a compression unit to compress the image data to a predetermined compression format; an omission secondary compression unit to omit a portion of the compressed image data given by the compression unit, divide the compressed image data into blocks having predetermined block sizes, and perform secondary compression to generate omission secondary compression image data; a data recovery unit to recover the omission secondary compression image data into the compressed image data; an image rotation unit to rotate the compressed image data decompressed by the data decompression unit according to the block sizes; a block storage unit to store the rotated compressed image data in units of the block sizes; and a data decompression unit to decompress the compressed image data stored in the block storage unit according to predetermined conditions.

Image processing apparatus and image processing method

Growing community of inventors

Kanagawa, Japan

Shiro Kofuji