Browse Prior Art Database

SCANLINE DELAY WINDOW COMPENSATION

IP.com Disclosure Number: IPCOM000027046D
Original Publication Date: 1995-Feb-28
Included in the Prior Art Database: 2004-Apr-07
Document File: 4 page(s) / 234K

Publishing Venue

Xerox Disclosure Journal

Abstract

Typically, the user specifies an area or window on which image processing functions are to be performed by entering coordinants of a rectangular area. These coordinants identify the corner pixels of the rectangle wherein the coordinant represents a scanline and a pixel (SL, PX). A window control function then decodes the coordinants by counting scanlines and pixels and turning ON the desired functions when the image processing operations encounters the initial pixel at the upper-most left corner of the rectangular window. Moreover, the window control function turns OFF the desired functions when the image processing operations depart the rectangular window.

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I

XEROX DISCLOSURE JOURNAL

 Image Processing Module 2

SCANLINE DELAY WINDOW COMPENSATION
Robert J. Dash
David B. Baum

Proposed Classification

U.S. C1.3181085 Int. C1. H02p 5/50

Scan Line and Pixel

XEROX DISCLOSURE JOURNAL - Vol. 20, No. 1 January/February 1995 17

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Video

Data

 Image N Scan Processing ---+

Module 1 Line Delay

Video

Data

[This page contains 2 pictures or other non-text objects]

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SCANLINE DELAY WINDOW COMPENSATION (Cont'd)

Typically, the user specifies an area or window on which image processing functions are to be performed by entering coordinants of a rectangular area. These coordinants identify the corner pixels of the rectangle wherein the coordinant represents a scanline and a pixel (SL, PX). A window control function then decodes the coordinants by counting scanlines and pixels and turning ON the desired functions when the image processing operations encounters the initial pixel at the upper-most left corner of the rectangular window. Moreover, the window control function turns OFF the desired functions when the image processing operations depart the rectangular window.

A problem is encountered in specifying functions to be carried out by the generation of a window is related to a time delay of N scanlines. More specifically, when a desired function B is at scanline X, a desired function A can be at scanline X + N. Thus, due to this delay of N scanlines, it is impossible for the user to apply both functions A and B to the same area since the scanline count for function A will always be N scanlines ahead of the scanline count for function B. In other words, if a single counter is utilized to track the osition of

will have N scanlines of image data to be processed within the window. In other words, function B will be prematurely terminated before the process reaches the end of the window area.

the image processing operation, function A will be completed while P unction B

This problem can be solved by using a separate counter for each specified image processing function. However, since a typical machine contains numerous image processing modules, the addition of a counter for each image processing module greatly increase the cost of such a machine. Therefore, it is desirable to separately track the numerous image processing operations without the utilization of separate counter.

It is proposed that the separate image processing operations can be tracked separately without utilizing a distinct counter for each image processing operation. More specifically, a separate window for each image processing function can be specified, thus allowing the separate tracking of the image processing operations without using separate counters.

If two sets of window coordinant decoders are available in a window control function module, a simple routine can be preprogrammed so that the user can apply both functions A and B to the same area. This routine can compensate for any real time delay by defining a separate real time...