Method and system for processing multi-level tone value images including text, graphic images and continuous tone images by using halftoning technique

An image processing system for binarizing a plurality of multilevel tone value images including at least a first multi-level tone value image and a second multi-level tone value image, said image processing system comprising:

• (a) a first converting device for converting said first multi-level tone value image into a first bitmap image consisting of binary values;
• (b) a replacing device for replacing each binary value of said first bitmap image representing an on condition by a maximum value in a tone value range of said second multi-level tone value image and replacing each binary value of said first bitmap image representing an off condition by a minimum value in said tone value range of said second multi-level tone value image;
• (c) a storage device for storing said first bitmap image, whose each binary value has been replaced by said maximum value or said minimum value in said tone value range of said second multi-level tone value image, and said second multi-level tone value image as a single intermediate image;
• (d) a second converting device for converting said intermediate image into a second bitmap image consisting of binary values, by using a threshold data matrix;
• and
• (e) an outputting device for outputting said second bitmap image.

A program storage device readable by a computer, tangibly embodying a program of instructions executable by said computer to perform method processes for binarizing a plurality of multi-level tone value images including at least a first multi-level tone value image and a second multi-level tone value image, said method processes comprising:

• (a) converting said first multi-level tone value image into a first bitmap image consisting of binary values;
• (b) replacing each binary value of said first bitmap image representing an on condition by a maximum value in a tone value range of said second multi-level tone value image, and replacing each binary value of said first bitmap image representing an off condition by a minimum value in said tone value range of said second multi-level tone value image;
• (c) managing said first bitmap image, whose each binary value has been replaced in said replacing process, and said second multilevel tone value image as a single intermediate image;
• (d) converting said intermediate image into a second bitmap image consisting of binary values, by using a threshold data matrix;
• and
• (e) outputting said second bitmap image.