Image analysis – Histogram processing – For setting a threshold
Patent
1990-12-03
1993-03-09
Boudreau, Leo H.
Image analysis
Histogram processing
For setting a threshold
382 18, 377 45, G06K 934
Patent
active
051931222
ABSTRACT:
A simple technique for determining and indicating, in real times as an image is scanned, the presence of halftones within a page. in brief, the technique contemplates monitoring a pixel stream, typically on a line basis, determining the proportion of pixel transitions (relative to the overall number of pixel intervals), and controlling the process based on this information. In one embodiment, a numerical value representing such a proportion is compared to a threshold, and a value in excess of the threshold is taken to signify the presence of halftone regions. Based on this, special processing for halftones is enabled or special processing for non-halftone regions is disabled. In a specific hardware embodiment, the pixel monitoring circuitry includes a transition detector (50), an up/down activity counter (52), a threshold selector (55), and a counter controller (57).
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Bloomberg Dan S.
Kowalski Robert P.
Boudreau Leo H.
Stellrecht Barry
Xerox Corporation
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