Patent ID: 8482801

Claim:
A method for processing image data in an image processing device, the image processing device including an image processing algorithm that can produce processed images that are either stored in a computer readable medium, generated as a physical hardcopy such as a print, or used to display an image, the image data including a plurality of scanlines with each scanline having a plurality of pixel positions, the method comprising: using a computer memory to store a starting stamp value for the scanline that includes at least one input pixel, the starting stamp value corresponding to a pixel threshold modification value for error diffusion; using the computer memory to store a plurality of delta stamp values for pixels in the scanline, the delta stamp values each representing a difference in pixel stamp values between two adjacent input pixels in the scanline, the pixel stomp values corresponding to pixel threshold modification values for error diffusion; receiving an input pixel intensity value for the input pixel; determining an output pixel intensity value for the input pixel; and determining a pixel stamp value for the input pixel from (1) a pixel stamp value for a previous pixel in the scanline and (2) a delta stamp value for the input pixel, the pixel stamp value relating to a countdown or stamp field method of stamp function, wherein when the output pixel intensity value for the input pixel is equal to a value of a dot in a highlight region or a hole in a shadow region, the stored delta stamp values for at least one adjacent pixel is updated to a predetermined value.