Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1993-04-27
1996-04-09
Coles, Sr., Edward L.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358447, 358458, 382264, H04N 140, G06K 940
Patent
active
055066992
ABSTRACT:
A method and apparatus for converting a binary image into a gray scale image includes a pipeline having a number of nearly identical stages. At each stage, modifications occur to provide the gray scale image by following a sequence of steps including: (1) determining a sample mean value representing an averaging of pixel values within a neighborhood containing a selected pixel; (2) determining a weighted variation value representing pixel value variations within the neighborhood; and (3) adjusting the pixel value of the selected pixel toward the sample mean value if the difference between the pixel value and the sample mean value exceeds the weighted variation value. The adjustment to the pixel value is in the direction of the sample mean value. Preferably, the weighting of the variation value is different at each stage. At each stage along the pipeline, low pass filtering is provided to remove high frequency noise generated by the process.
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Coles Sr. Edward L.
Esposo Allan A.
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