Method of displaying continuous tone picture using limited number of different colors or black-and-white levels, and display system therefor

A method of displaying continuous tone images from input color data signals representing each color of a respective picture element of picture elements forming a plurality of lines of an image to be displayed by parallel processing of lines in sequence, comprising the steps of:

• (a) comparing each of the input color data signals forming a first line of said image with a plurality of standard color data signals each representing a respective one of a plurality of displayable colors and selecting for each input color data signal the one standard value data signal which is closest to that input image value data signal;
• (b) calculating the quantifying error between each input color data signal forming said first line of said image and the standard color data signal selected for each input color data signal;
• (c) generating a respective compensation quantity for each input color data signal of said first line of said image based on predetermined weighting coefficients and the quantifying error for that input color data signal and the quantifying errors of a predetermined number of adjacent input color data signals;
• (d) adding the generated compensation quantity for each input color data signal of said first line only to a color data signal of a subsequent line of said image to be displayed to produce a compensated set of said input color data signals;
• (e) repeating steps (a) through (d) until standard color data signals have been selected for the input color data signals of all of the lines of said image;
• and
• (f) displaying said selected standard color data signals to produce the appearance of a continuous tone image.

A method of displaying continuous tone images from input color data signals representing each color of a respective picture element of picture elements forming a plurality of successive lines of an image to be displayed by parallel processing of lines in sequence, comprising the steps of:

• (a) comparing each of the input color data signals forming a first line of said image with a plurality of standard color data signals each representing a respective one of a plurality of displayable colors and selecting for each input color data signal the one standard value data signal which is closest to that input image value data signal;
• (b) calculating the quantifying error between each input color data signal forming said first line of said image and the standard color data signal selected for each input color data signal;
• (c) generating a respective compensation quantity for each input color data signal of said first line of said image based on predetermined weighting coefficients and the quantifying error for that input color data signal and the quantifying errors of a predetermined number of adjacent input color data signals in said first line;
• (d) adding the generated compensation quantity for each input color data signal of said first line only to a corresponding color data signal of a second line of said image to be displayed to produce a compensated set of said input color data signals of said second line;
• (e) repeating steps (a) through (d) until standard color data signals have been selected for the input color data signals of all of the lines of said image;
• and
• (f) displaying said selected standard color data signals to produce the appearance of a continuous tone image.

A system for displaying continuous tone images from input color data signals representing each color of a respective picture element of picture elements forming a plurality of successive lines of an image to be displayed by parallel processing of line in sequence, comprising:

• means for comparing each of the input color data signals forming a first line of said image with a plurality of standard color data signals each representing a respective one of a plurality of displayable colors and selecting for each input color data signal the one standard color data signal which is closest to that input color data signal;
• means for calculating the quantifying error between each input color data signal forming said first line of said image and the standard color data signal selected for each input color data signal;
• means for generating a respective compensation quantity for each input color data signal of said first line of said image based on predetermined weighting coefficients and the quantifying error for that input color data signal and the quantifying errors of a predetermined number of adjacent input color data signals in said first line;
• means for adding the generated compensation quantity for each input color data signal of said first line only to a corresponding color data signal of a second line of said image to be displayed to produce a compensated set of said input color data signals of said second line;
• and
• means for displaying said selected standard color data signals to produce the appearance of a continuous tone image.