US4052715A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital half-tone grey scale expansion system
Assignee: Xerox Corp
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Filing: 1976-02-25
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Granted: 1977-10-04
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Expires: 1996-02-25
Abstract
Abstract Method and apparatus for expanding the number of grey scale values in a digital flying-spot scanning system. The scanned recording medium is divided into a plurality of unit cells, each of which is assigned a desired grey scale value, and each unit cell is further divided into a plurality of subcells formed by a plurality of adjacent portions of scan lines comprising digitally controlled segments. The grey scale value of the unit cell is dependent upon the portion of the subcells within the unit cell which are activated or deactivated by the scanning beam. Additionally, the number of grey scale values between particular numbers of activated subcells is expanded by providing varying patterns of predetermined numbers of subcells within the unit cell with the varying patterns producing the optical effect of varying grey scale levels.
Inventors
- 👤 William Streifer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:18
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
161 words
A variable half-tone image generating system for use in a flying-spot scanning system comprising: an image surface having at least one unit cell which is divided into a plurality of elemental sub-cells of a given area, means for producing a light beam of high intensity, means adapted to scan said light beam across each of said sub-cell areas of said at least one unit cell, and means for both (1) modulating the intensity of said light beam so that only a selected number of said sub-cell areas within said at least one unit cell are exposed to said scanning light beam and (2) varying the position of said selected number of sub-cells within said at least one unit cell so that the ratio of the area of said selected number of sub-cells to the unexposed perimeter of said selected number of sub-cells varies to thereby provide a varying grey scale within said unit cell from a fixed number of exposed sub-cells.
Claim 2
Dependent Claim
161 words
A variable half-tone image generating system for use in a flying-spot scanning system comprising: an image surface having at least one unit cell which is divided into a plurality of elemental sub-cells of a given area, means for producing a light beam of high intensity, means adapted to scan said light beam across each of said sub-cell areas of said at least one unit cell, and means for both (1) modulating the intensity of said light beam so that only a selected number of said sub-cell areas within said at least one unit cell are exposed to said scanning light beam and (2) varying the position of said selected number of sub-cells within said at least one unit cell so that the ratio of the area of said selected number of sub-cells to the unexposed perimeter of said selected number of sub-cells varies to thereby provide a varying grey scale within said unit cell from a fixed number of exposed sub-cells.
Claim 3
Independent Claim
152 words
A method for providing a number of grey scale values on an image surface from a fixed number of addressed areas of said image surface comprising the steps of: dividing said image surface into a plurality of unit cells arrayed across said image surface and subdividing each of said unit cells into a plurality of arrayed sub-cells of a given area, selecting a predetermined number of said sub-cells of at least one of said unit cells to be exposed to a light beam, and varying the location of said predetermined number of sub-cells within said at least one unit cell to vary the perimeter to area ratio of said sub-cells of said at least one unit cell exposed to said light beam to thereby provide a number of grey scale values within said at least one unit cell from a fixed number of exposed sub-cells of said at least one unit cell.
Claim 4
Independent Claim
152 words
A method for providing a number of grey scale values on an image surface from a fixed number of addressed areas of said image surface comprising the steps of: dividing said image surface into a plurality of unit cells arrayed across said image surface and subdividing each of said unit cells into a plurality of arrayed sub-cells of a given area, selecting a predetermined number of said sub-cells of at least one of said unit cells to be exposed to a light beam, and varying the location of said predetermined number of sub-cells within said at least one unit cell to vary the perimeter to area ratio of said sub-cells of said at least one unit cell exposed to said light beam to thereby provide a number of grey scale values within said at least one unit cell from a fixed number of exposed sub-cells of said at least one unit cell.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-03 | 1981-04-04 | 1981-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-03 | 1985-04-04 | 1985-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-03 | 1989-04-04 | 1989-10-04 | $7700.00 | Window Closed / Lapsed |