Abstract: An image processing method for detection and removal of halftone dots includes converting a gray scale image into a binary thresholded image with halftone dots; identifying halftone regions within the binary thresholded image; and removing halftone dots from the identified halftone regions. The identifying halftone regions step is effected by classifying the binary thresholded image to produce a halftone classification map; reclassifying the halftone classification map to produce a halftone reclassification map of lines with plural halftone pixels in each line; merging the halftone pixels in each line in the halftone reclassification map to produce a halftone line map; and merging the lines of the halftone line map to produce a halftone region map.

Abstract: A technique, specifically apparatus and an accompanying method, for accurately thresholding an image based on local image properties, specifically luminance variations, and particularly such a technique that uses multi-windowing for providing enhanced immunity to image noise and lessened boundary artifacts. Specifically, a localized intensity gradient, G(i,j), is determined for a pre-defined window (300) centered about each image pixel (i, j ) . Localized minimum and maximum pixel intensity measures, L.sub.min and L.sub.max, respectively, are also determined for another, though larger, window (330) centered about pixel (i,j). Also, a localized area gradient measure, GS(i,j), is determined as a sum of individual intensity gradients for a matrix of pixel positions (370) centered about pixel position (i,j). Each image pixel (i,j) is then classified as being an object pixel, i.e., black, or a background pixel, i.e., white, based upon its area gradient, GS (i,j), and associated L.sub.min and L.sub.max measures.

Abstract: An LED Printhead having a row of LED's includes a binary architectured driver that drives each LED on for a series of sub-intervals related to a series of binary weighted recording clocking pulses to record a grey level pixel in accordance with an appropriate series of data bits latched in the driver. The series of data bits are formatted for presentation to the driver by a retransmit line buffer which transmits n times the data of one line of grey level pixels represented by n bits each to a process correction look-up table. Another look-up table provides a signal to the process look-up table as to the intensity characteristics of the particular LED which is to print the pixel. The corrected grey level data is then input to a multiplexer which selects one of the n bits for printing in accordance with count signals related to the binary weight of the recording clock pulses.