Fuji Xerox Co., Ltd.

Shinji Shishido

Yutaka Koshi

Koh Kamizawa

Akihiro Andoh

Shunichi Kimura

Setsu Kunitake

Masanori Sekino

Ikken So

An image coding apparatus includes an approximating element having plural different prediction techniques to approximate, a value of a target pixel to be coded with reference to values of peripheral pixels surrounding the target pixel; a holding element which holds information about ranks of the prediction techniques, the ranks obtained upon processing of the pixel preceding the target pixel; a determining element computing an error between each of approximate values obtained by the prediction techniques and that of the target pixel, selecting one of the prediction techniques for the target pixel based on the computer error, and performing the selection by preferentially referencing the rank information if the error is within a predetermined tolerance; and a coding element which codes the value of the target pixel using the approximate value obtained by the selected prediction technique.

Image coding apparatus and image coding method

Images are to be efficiently and easily encoded while suppressing block distortion and pseudo-contour generation. A quantization characteristics determining unit receives pixel values from a pixel value input unit, measures the length S of the consecutive occurrence of the same pixel values in connection with a pixel to be encoded and the pixel value differences D, and determines quantization characteristics n with reference to the result of sensory evaluation. A quantization/inverse quantization unit quantizes pixel values to be inputted with the quantization characteristics n, and further inverse quantizes them to reduce the number of gray-scale levels. The output pixel values of the quantization/inverse quantization unit are encoded and outputted by an entropy encoding unit.

Image encoding apparatus and quantization characteristics determining apparatus

The present invention has an object to determine whether image data is generated by data processing such as PDL, or optically captured scan-in image, for each area. To achieve the object, a determining table is provided for distribution patterns of pixels having substantially the same pixel value for image data area composed of plural pixels. Then a reference area designating unit designates a reference area by selecting from input image data the pixel of interest having a pixel value and the reference pixels surrounding thereof. A same pixel value distribution generating unit compares the pixel value of the pixel of interest with the pixel values of the reference pixels in the reference area to generate a distribution pattern of the pixel having substantially the same pixel value. Next, a determining unit compares the generated distribution pattern with the distribution patterns held in the determining table to determine the reference area to be the image data generated by data processing.

Image processing apparatus

The memory capacity required for temporarily holding image data with respect to a printer is reduced, and loads involved in supplying image data, such as decoding and conversion processes, are dispersed and reduced. The apparatus divides image data in parallel with a main scanning direction by an image divider, stores the divided data in image data memory, and supplies the divided image data to image data temporary memory by an image data supply to perform a decoding process. In order to provide a matching with a process speed, the image data temporary memory temporarily retains the divided image data, and a printer prints an image on a sheet of paper on the basis of the divided image data stored in the image data temporary memory. A predictor predicts a supply process time by way of image data supply, and an image data supply control causes the image data supply to start the supply process of the divided image data at a time preceding the time for the start of the print process by the printer according to the time predicted.

Image forming apparatus

In an image forming apparatus, memory capacity necessary for temporarily retaining image data is reduced. A decoding process is carried out by diving image data for one frame into element data for each color component Y, M, C and K. The element data for each color component is stored in the temporary memory. A controller starts conveyance of recording media on the basis of estimation of the completion time of decoding processing by a decoding speed estimator, and controls the recorders for Y, M, C and K to execute the recording process of element data retained in the temporary memory. This results in an image being recorded on the recording medium for each element data retained in the temporary memory, such that the conveyance of the recording media and the supply of data to the recorders for Y, M, C and K are matched, and the data amount to be retained in the temporary memory is reduced.

An auxiliary storage controlling device is able to assure the data transferring rate even when an irregular occurs. The controlling device comprises a plurality of auxiliary storage units each of which stores the same data, a readout system for reading out said data from said plurality of auxiliary storage units simultaneously in response to a readout command, a detecting system for detecting an auxiliary storage unit in which the reading out of said data is finished at the earliest, a selecting system for selecting said data which is read from said detected auxiliary storage unit, an irregular detecting system for detecting an irregular auxiliary storage unit which is still working, and a readout prohibiting system for prohibiting a consecutive readout command against said irregular auxiliary storage unit. Additional features to assure the data transferring rate are also disclosed.

Auxiliary storage controlling method and auxiliary storage controlling

The order of pixel data is converted on a frame-by-frame basis to produce a prescribed combination of pixel data. To construct frames, sequence numbers representing the order of the frames are attached to respective frame data each composed of a plurality of pixel data thus produced. The frames thus constructed are transmitted to the transmission line. On the receiving side, the sequence numbers of the frames received from the transmission line are checked to detect a missing frame. Pixel data of the missing frame is replaced by those of a frame having a sequence number immediately before that of the missing frame. An image is reconstructed by inversely converting the order of the pixel data which include the replaced pixel data.

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Nakai-machi, Japan

Shinji Shishido