Patent ID: 6078691
Filing Date: 2000-06-20
Classification: G06K,G06T

Abstract:
A method of performing an image processing operation on pixels of one or more images divided into pixels, wherein an image is represented by a series of consecutive runs with runlengths and corresponding pixel values wherein a runlength represents the number of consecutive pixels having mutually identical pixel values and the image processing operation is performed successively on groups of consecutive pixels, the method comprising the steps of:a first selection step for selecting at least two runs from one or more series of runs of one or more images on the basis of pixel position information including values for a column and a row of each image;a runlength processing operation for processing the runlengths and the pixel values of the runs selected in said first selection step in accordance with the image processing operation in order to obtain a resultant run having a resultant runlength and a resultant pixel value;a shortening step for shortening at least one of the runlengths of the selected runs by a value derived from the determined resultant runlength;storing the resultant run in a series of resultant runs;a step size determining step for determining a step size derived from the resultant runlength;a second selection step for selecting the one or more shortened runs and/or one or more following runs from the one or more series of runs representing the one or more images on the basis of the step size determined by said step size determining step; andrepeatedly performing the above steps until all the runs have been processed;said first and second selecting steps selecting runs from a first and a second series of runs which represent a first and second image respectively, wherein runs with an identical pixel starting position are selected from both series in each of said first and second selection steps;said runlength processing operation including the following steps:comparing the pixel value for a run from the first series with the pixel value of a run from the second serieswherein in a first event that the pixel value of the first run has a first value, the pixel value of the run from the second series is selected as the value of a resultant run andwherein in a second event the pixel value of the run from the first series is selected as the resultant pixel value of the resultant run;the method further comprising:a smallest runlength selecting step for selecting the smallest runlength of the runs from the first and second series as the resultant runlength of the resultant run;said shortening step shortening the runlength of the largest selected runlength by the length of the resultant runlength; andsaid step size determining step takes the resultant runlength as the step size.