Half-tone image processing system

A half-tone image processing system, comprising:

• density data storage means for storing density data of each pixel of an original image;
• Laplacian calculation means for reading out the density data from the density data storage means, for performing a Laplacian calculation on an object pixel and peripheral pixels around the object pixel to obtain corrected data, the Laplacian calculation being performed in such a manner that a difference in density between the object pixel and each of the peripheral pixels is calculated and all the differences are summed;
• average error calculation means for receiving a binary-coded error and an error weighted matrix and for obtaining average correction data based on the binary coded error and the error weighted matrix;
• addition means for adding the corrected data of the object pixel, and the average correction data to output resultant data;
• binary-coding means for comparing the resultant data with a fixed threshold value to obtain binary-coded data indicating either black or white color in accordance with the fixed threshold value;
• and
• error calculation means for obtaining a difference between the resultant data and the binary-coded data to output binary-coded error.

A half-tone image processing system, comprising:

• density data storage means for storing density data of each pixel of an original image;
• Laplacian calculation means for reading out the density data from the density data storage means, for performing a Laplacian calculation on an object pixel and peripheral pixels around the object pixel to obtain corrected data, the Laplacian calculation being performed in such a manner that a difference in density between the object pixel and each of the peripheral pixels is calculated and all the differences are summed;
• binary-coding means for comparing the corrected data and the density data of the object pixel to obtain binary-coded data indicating either block or white color in accordance with the density data of the object pixel;
• error calculation means for determining a difference between the density data and the binary-coded data to obtain a binary-coded error;
• an error distribution means for receiving the binary-coded error and a predetermined error diffusion matrix and for obtaining a weighted binary-coded error for each peripheral pixel based on the received binary-coded error and the predetermined error diffusion matrix;
• and
• calculation means for adding the weighted binary-coded error to the density data corresponding to each peripheral pixel to produce corrected density data, and for replacing the density data in the density data storage means.

A half-tone image processing system, comprising:

• density data storage means for storing density data of each pixel of an original image;
• Laplacian calculation means for reading out the density data from the density data storage means, for performing a Laplacian calculation on an object pixel and peripheral pixels around the object pixel to obtain corrected data, the Laplacian calculation being performed in such a manner that a difference in density between the object pixel and each of the peripheral pixels is calculated and all the differences are summed;
• average error calculation means for receiving a binary-coded error and an error weighted matrix, and for obtaining average correction data based on the binary coded error and the error weighted matrix;
• addition means for adding the density data of the object pixel and the average correction data to output resultant data;
• binary-coding means for comparing the resultant data and the corrected data to obtain binary-coded data indicating either black or white color in accordance with the corrected data;
• and
• error calculation means for obtaining a difference between the resultant data and the binary-coded data to output a binary-coded error.

A half-tone image processing system for processing an image made of pixels having density data wherein one of the pixels is an object pixel and pixels around the object pixel are peripheral pixels, comprising:

• Laplacian calculation means for determining differences in density between the object pixel and each of the peripheral pixels and for summing the differences to obtain corrected data;
• binary-coding means for thresholding based on at least the corrected data to obtain binary-coded data;
• and
• error calculation means for determining a difference based on at least the binary coded data to obtain a binary-coded error.