Abstract: A method and system detects a halftone frequency. A digitized image is received. An autocorrelation function is performed upon the digitized image to generate an autocorrelation function value for each halftone frequency of a predetermined set of possible halftone frequencies. A demerit term for each possible halftone frequency, based upon the autocorrelation function value, is calculated. A halftone frequency from a predetermined set of possible halftone frequencies, based upon the calculated demerit terms, is selected.

Abstract: One aspect of the invention provides a method of halftoning an image which involves determining a quantization error for a selected target pixel of an image, selecting a diffusion mask, the mask relating to the target pixel and pixels neighboring thereto, receiving a first pair of neighboring pixel values for a first pixel pair including a first neighboring pixel and a second neighboring pixel, and receiving a second pair of neighboring pixel values for a second pixel pair including a third neighboring pixel and a fourth neighboring pixel. The method further involves determining a ranking order of the first, second, third and fourth neighboring pixels by comparing pixel values of the first, second, third and fourth neighboring pixels, and diffusing error to at least one of the first, second, third and fourth neighboring pixels based on the determined ranking order of the first, second, third and fourth neighboring pixels.

Abstract: A method and system detects a halftone frequency. A digitized image is received. An autocorrelation function is performed upon the digitized image to generate an autocorrelation function value for each halftone frequency of a predetermined set of possible halftone frequencies. A demerit term for each possible halftone frequency, based upon the autocorrelation function value, is calculated. A halftone frequency from a predetermined set of possible halftone frequencies, based upon the calculated demerit terms, is selected.