US 5,177,797 AGranted

Block transformation coding and decoding system with offset block division

AssigneeFujitsu Limited

InventorsYuji Takenaka, Yoshitsugu Nishizawa, Takahiro Hosokawa, Yuji Mori, Hideki Miyasaka

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Abstract

An image data coding system, wherein an image data in a bit map form is divided into first and second groups, pixels in each group of which are distributed over the whole area of the image data in the bit map form. First and second coders respectively code the first and second groups of image data into first and second groups of coded image data. The first and second groups of image data in the original image data are respectively input into first and second memories, respectively. Blocks of the first group of image data are supplied to the first coder at first times, respectively, and blocks of the second group of image data are supplied to the second coder at second times, respectively. Boundaries of the blocks in the first group of image data are located in different positions from boundaries of the blocks in the second group of image data, and the first times are different from the second times. In the receiver side, first and second decoders respectively decode the above first and second groups of coded image data into first and second groups of decoded image data. By composing the first and second groups of decoded image data, the original image data in the bit map form is restored.

Claims11

Dependent claims

An image data coding and decoding system for coding and decoding pixels in bit map frames comprising:

an image data coder comprising:
first block supply means for receiving a first group of pixels from the bit map frames and for dividing the first group into a plurality of first blocks along first boundaries, each first block containing a predetermined number of pixels;
second block supply means for receiving a second group of pixels from the bit map frames, the second group being interlaced with the first group, and for dividing the second group into a plurality of second blocks along second boundaries chosen to be offset by a predetermined distance from the first boundaries, each second block containing the predetermined number of pixels;
a first coder connected to receive and code the first blocks from said first block supply means by block transformation coding;
and
a second coder connected to receive and code the second blocks from said second block supply means by block transformation coding;
and
an image data decoding apparatus comprising:
a first decoder operatively coupled to said first coder;
a second decoder operatively coupled to said second coder;
bit map memory means for receiving first and second blocks from said first and second decoders and for storing the pixels from the first and second blocks to produce pixels in bit map frames;
first block transfer means for transferring the first blocks from said first decoder to said bit map memory means;
and
second block transfer means for transferring the second blocks from said second decoder to said bit map memory means, the predetermined distance being determined such that a block like pattern is reduced in a decoded image constituted by the pixels in the bit map frames stored in said bit map memory means.

11 more elements

An image data coding apparatus for coding pixels in bit map frames comprising:

first block supply means for receiving a first group of pixels from the bit map frames and for dividing the first group into a plurality of first blocks along first boundaries, each first block containing a predetermined number of pixels;
second block supply means for receiving a second group of pixels from the bit map frames, the second group being interlaced with the first group, and for dividing the second group into a plurality of second blocks along second boundaries chosen to be offset by a predetermined distance from the first boundaries, each second block containing the predetermined number of pixels, the predetermined distance being determined such that a block like pattern is reduced when the image is decoded;
a first coder connected to receive and code the first blocks from said first block supply means by block transformation coding;
and
a second coder connected to receive and code the second blocks from said second block supply means by block transformation coding.

2 more elements

An image data decoding apparatus for decoding coded data to provide pixels in bit map frames comprising:

a first decoder connected to receive the coded data and provide a plurality of first blocks, each of the first blocks defined by first boundaries dividing a first group of the pixels so that each of the first blocks contain a predetermined number of pixels;
a second decoder connected to receive the coded data and provide a plurality of second blocks, each of the second blocks defined by second boundaries dividing a second group of the pixels so that each of the second blocks contains the predetermined number of pixels, the second group being interlaced with the first group;
bit map memory means for receiving the first and second blocks from said first and second decoders and for storing the pixels from the first and second blocks to produce the pixels in the bit map frames;
first block transfer means for transferring the first blocks from said first decoder to said bit map memory means;
and
second block transfer means for transferring the second blocks from said second decoder to said bit map memory means so that the second boundaries dividing the second group of the pixels are offset by a predetermined distance from the first boundaries, the predetermined distance being determined such that a block like pattern is reduced in a decoded image constituted by the pixels in the bit map frames in said bit map memory means.

3 more elements

Dependencies are inferred from the claim text.