US4945422A
Expired / Lapsed
US
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False density contour suppression using stored random probabilities to form print/no-print decisions
Assignee: Eastman Kodak Co
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Filing: 1990-01-02
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Granted: 1990-07-31
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Expires: 2010-01-02
Abstract
Abstract False contouring of a screened halftone image without including more sub-elements in each cell, increasing the size of each cell, or decreasing the screen frequency of the image is accomplished by assigning to each sequential sub-element of a halftone cell a weighted probability of being "ON" in accordance with the value of the associated input signal. The weighted probability signal is converted to a binary value without a real time random number generator by a memory device having a plurality of rows, wherein each row represents a different probability that a sub-element will be "ON". The rows are accessed on the basis of the weighted probability of a sub-element being "ON".
Inventors
- 👤 Yee S. Ng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:53
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
129 words
Apparatus for suppressing false density contours in halftone reproduction of continuous tone original images which have been converted to a series of discrete picture element signals, said apparatus comprising: means for selectively printing sub-elements sequentially organized into halftone cells; means for assigning to each sequential sub-element of a halftone cell a weighted probability of being "ON" in accordance with the value of an associated picture element signal; and means for converting the weighted probability of each sub-element into a print/no-print decision, said converting means including (1) memory means having a plurality of rows, wherein each row represents a different probability that a sub-element will be "ON", and (2) means for accessing different rows of said memory means on the basis of the weighted probability of a sub-element being "ON".
Claim 2
Dependent Claim
129 words
Apparatus for suppressing false density contours in halftone reproduction of continuous tone original images which have been converted to a series of discrete picture element signals, said apparatus comprising: means for selectively printing sub-elements sequentially organized into halftone cells; means for assigning to each sequential sub-element of a halftone cell a weighted probability of being "ON" in accordance with the value of an associated picture element signal; and means for converting the weighted probability of each sub-element into a print/no-print decision, said converting means including (1) memory means having a plurality of rows, wherein each row represents a different probability that a sub-element will be "ON", and (2) means for accessing different rows of said memory means on the basis of the weighted probability of a sub-element being "ON".
Claim 3
Dependent Claim
153 words
Apparatus for suppressing false density contours in halftone reproduction of continuous tone original images which have been converted to a series of discrete picture element signals, said apparatus comprising: means for selectively printing sub-elements sequentially organized into halftone cells; means for assigning to each sequential sub-element of a halftone cell a weighted probability of being "ON" in accordance with the value of an associated picture element signal; and means for converting the weighted probability of each sub-element into a print/no-print decision, said converting means including memory means having (1) a plurality of rows, wherein each row represents a different probability that a sub-element will be "ON", and (2) a plurality of memory locations in each row, said memory locations being filled with print and no-print commands randomly distributed within the row, with the percent of print commands being equal to the percent probability that the sub-element represented by that row will be "ON".
Claim 4
Dependent Claim
153 words
Apparatus for suppressing false density contours in halftone reproduction of continuous tone original images which have been converted to a series of discrete picture element signals, said apparatus comprising: means for selectively printing sub-elements sequentially organized into halftone cells; means for assigning to each sequential sub-element of a halftone cell a weighted probability of being "ON" in accordance with the value of an associated picture element signal; and means for converting the weighted probability of each sub-element into a print/no-print decision, said converting means including memory means having (1) a plurality of rows, wherein each row represents a different probability that a sub-element will be "ON", and (2) a plurality of memory locations in each row, said memory locations being filled with print and no-print commands randomly distributed within the row, with the percent of print commands being equal to the percent probability that the sub-element represented by that row will be "ON".
Claim 5
Dependent Claim
25 words
Apparatus as set forth in claim 2 further comprising addressing means for accessing a row based on the weighted probability of a sub-element being "ON".
Claim 6
Dependent Claim
37 words
Apparatus as set forth in claim 2 further comprising: addressing means for accessing a row based on the weighted probability of a sub-element being "ON"; and means for randomly selecting a memory location of an accessed row.
Claim 7
Dependent Claim
112 words
Apparatus for suppressing false density contours in halftone reproduction of continuous tone original images which have been converted to a series of discrete picture element signals, said apparatus comprising: means for selectively printing sub-elements sequentially organized into halftone cells; means for assigning to each sequential sub-element of a halftone cell a weighted probability of being "ON" in accordance with the value of an associated picture element signal; and means for converting the weighted probability of each sub-element into a print/no-print decision, said converting means including memory means having a plurality of rows and columns, wherein each row represents a uniform probability increment from 0% to 100% that a sub-element will be "ON".
Claim 8
Dependent Claim
112 words
Apparatus for suppressing false density contours in halftone reproduction of continuous tone original images which have been converted to a series of discrete picture element signals, said apparatus comprising: means for selectively printing sub-elements sequentially organized into halftone cells; means for assigning to each sequential sub-element of a halftone cell a weighted probability of being "ON" in accordance with the value of an associated picture element signal; and means for converting the weighted probability of each sub-element into a print/no-print decision, said converting means including memory means having a plurality of rows and columns, wherein each row represents a uniform probability increment from 0% to 100% that a sub-element will be "ON".
Claim 9
Dependent Claim
30 words
Apparatus as set forth in claim 5 further comprising means for accessing different rows of said memory means on the basis of the weighted probability of a sub-element being "ON".
Claim 10
Dependent Claim
19 words
Apparatus as set forth in claim 6 further comprising means for randomly selecting a column of an accessed row.
References Cited (Backward Citations)
US4245258A
Cited
US4821109A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-30 | 1994-01-29 | 1994-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-30 | 1998-01-29 | 1998-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-30 | 2002-01-29 | 2002-07-31 | $7700.00 | Window Closed / Lapsed |