Patent US2845758A successfully refreshed from Google Patents.
Patent US3752916A successfully refreshed from Google Patents.
US3752916A
Expired / Lapsed
US
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Method and apparatus for improving the horizontal sharpness of electronically scanned images
Assignee: DIGITAL LASER TRANSFORM Ltd
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Filing: 1971-09-30
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Granted: 1973-08-14
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Expires: 1991-09-30
Abstract
Abstract Superior sharpness at interface between low-and high-intensity image areas of an electronically scanned image is obtained by controlling the scan speed of the beam in addition to, and in accordance with changes in, its intensity. The scan speed variation signal is produced by time-delaying and mathematically processing the incoming intensity signal. In the preferred embodiment, the scan speed variation signal is superimposed upon the linear horizontal scan signal by applying it to an extra push-pull-connected pair of horizontal deflection plates.
Inventors
- 👤 J Lowry
- 👤 K Holland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:18
CPC Classifications
H; H04; H04N; H04N3/00; H04N3/10; H04N3/30; H04N3/32; H04N5/00; H04N5/14; H04N5/20; H04N5/205; H04N5/208
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
125 words
A method of producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising the steps of: a. deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal: b. using said control signal to vary the scan velocity of said scanning beam; c. delaying said intensity signal; and d. causing said control signal to have an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at the center of said transition, and gradually decreases after said transition, so as to cause an abrupt change in the scan velocity of said scanning beam during said transition.
Claim 2
Independent Claim
125 words
A method of producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising the steps of: a. deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal: b. using said control signal to vary the scan velocity of said scanning beam; c. delaying said intensity signal; and d. causing said control signal to have an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at the center of said transition, and gradually decreases after said transition, so as to cause an abrupt change in the scan velocity of said scanning beam during said transition.
Claim 3
Dependent Claim
34 words
The method of claim 1, further comprising the step of causing the sign of said control signal to be determined by the direction in which said intensity signal amplitude changes during said amplitude transition.
Claim 4
Independent Claim
149 words
A method of producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising the steps of: a. deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal; b. using said control signal to vary the scan velocity of said scanning beam; c. delaying said intensity signal; and d. causing said control signal to have an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at substantially the center of said transition, and gradually decreases after said transition, so as to cause an abrupt change in the scan velocity of said scanning beam during said transition, peak being displaced from the midpoint of said transition in one direction for increasing-intensity transitions, and in the opposite direction for decreasing-intensity transitions.
Claim 5
Independent Claim
149 words
A method of producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising the steps of: a. deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal; b. using said control signal to vary the scan velocity of said scanning beam; c. delaying said intensity signal; and d. causing said control signal to have an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at substantially the center of said transition, and gradually decreases after said transition, so as to cause an abrupt change in the scan velocity of said scanning beam during said transition, peak being displaced from the midpoint of said transition in one direction for increasing-intensity transitions, and in the opposite direction for decreasing-intensity transitions.
Claim 6
Independent Claim
129 words
A method of producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising the steps of: a. deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal; b. using said control signal to vary the scan velocity of said scanning beam; c. delaying said intensity signal; d. causing said coNtrol signal to have an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at substantially the center of said transition, and gradually decreases after said transition, said sharp amplitude peaking occurring only at those transitions of said delayed intensity signal which have less than a predetermined transition time.
Claim 7
Independent Claim
129 words
A method of producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising the steps of: a. deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal; b. using said control signal to vary the scan velocity of said scanning beam; c. delaying said intensity signal; d. causing said coNtrol signal to have an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at substantially the center of said transition, and gradually decreases after said transition, said sharp amplitude peaking occurring only at those transitions of said delayed intensity signal which have less than a predetermined transition time.
Claim 8
Dependent Claim
147 words
Apparatus for producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising: a. means for receiving said intensity signal; b. means for deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal; c. means responsive to said control signal for varying the scan velocity of scanning beam; d. means for delaying said intensity signal; and e. means for causing said control signal to have a sign determined by the direction of said amplitude variation, and an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at substantially the center of said transition, and gradually decreases after said transition, so as to cause an abrupt change in the scan velocity of said scanning beam at said transition.
Claim 9
Dependent Claim
147 words
Apparatus for producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising: a. means for receiving said intensity signal; b. means for deriving from said intensity signal a control signal related to variations in the amplitude of said intensity signal; c. means responsive to said control signal for varying the scan velocity of scanning beam; d. means for delaying said intensity signal; and e. means for causing said control signal to have a sign determined by the direction of said amplitude variation, and an amplitude which gradually increases prior to the transition of said delayed intensity signal, peaks sharply at substantially the center of said transition, and gradually decreases after said transition, so as to cause an abrupt change in the scan velocity of said scanning beam at said transition.
Claim 10
Dependent Claim
39 words
Apparatus according to claim 5, said last-named means being arranged so that said abrupt change of slope is displaced from the midpoint of said transition in one direction for increasing-intensity transitions, and in the opposite direction for decreasing-intensity transitions.
Claim 11
Dependent Claim
139 words
Apparatus for producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising: a. means for receiving an original intensity signal; b. means for producing at least one delayed intensty signal from said original intensity signal; c. delaying and comparing means for deriving from said intensity signals a pair of mutually delayed difference signals each representing the difference between two of said intensity signals; d. means for comparing at least a portion of each of said mutually delayed difference signals to derive therefrom a peaked control signal; and e. means for operatively combining said control signal with the scan signal of said scanning beam to produce an abrupt change in the scan velocity of said beam at said peak of said control signal.
Claim 12
Dependent Claim
139 words
Apparatus for producing substantially instantaneous exposure transitions on a target scanned by a scanning beam whose intensity is controlled by a variable intensity signal having a limited bandwidth, comprising: a. means for receiving an original intensity signal; b. means for producing at least one delayed intensty signal from said original intensity signal; c. delaying and comparing means for deriving from said intensity signals a pair of mutually delayed difference signals each representing the difference between two of said intensity signals; d. means for comparing at least a portion of each of said mutually delayed difference signals to derive therefrom a peaked control signal; and e. means for operatively combining said control signal with the scan signal of said scanning beam to produce an abrupt change in the scan velocity of said beam at said peak of said control signal.
Claim 13
Dependent Claim
36 words
Apparatus according to claim 7, further including means for causing the amplitude of said control signal at any given time to be the lower of the amplitudes of the signals being compared by said comparing means.
Claim 14
Dependent Claim
44 words
Apparatus according to claim 7, further including means for causing the magnitude of said delays to be such that said control signal is peaked substantially only for intensity transitions having less than a predetermined transition time, and becomes substantailly rounded for slower intensity transitions.
Claim 15
Dependent Claim
26 words
Apparatus according to claim 7, in which said means for operatively combining said control signal with said scan signal include means for amplifying said control signal.
Claim 16
Dependent Claim
12 words
Apparatus according to claim 10, in which said amplifying means are nonlinear.
Claim 17
Dependent Claim
38 words
Apparatus according to claim 11, in which said amplifying means emphasize low signal amplitudes substantially more than high signal amplitudes but substantially preserve the abruptness of the change of slope of said control signal at the peak thereof.
Claim 18
Dependent Claim
17 words
Apparatus according to claim 11, further comprising control means for controlling the gain of said amplifying means.
Claim 19
Dependent Claim
149 words
Apparatus for producing sharp edge effects in a scanned picture in which a sharp edge in scanned picture is represented by an intensity transition having a predetermined minimum transition time dictated by bandwidth restrictions, comprising: a. delaying and comparing means for deriving From the intensity signal a control signal whose amplitude gradually increases prior to the transition, peaks sharply at the center of the transition, and gradually decreases after the transition, and whose sign is determined by the direction of the transition; and b. means for varying the sweep velocity of the picture scan in accordance with said control signal; c. said delaying and comparing means being so arranged that the peak amplitude and peaking sharpness of said control signal rapidly diminishes as the transition time of an intensity transition in said picture increases beyond said predetermined minimum transition time associated with a sharp edge in said original scene.
Claim 20
Dependent Claim
149 words
Apparatus for producing sharp edge effects in a scanned picture in which a sharp edge in scanned picture is represented by an intensity transition having a predetermined minimum transition time dictated by bandwidth restrictions, comprising: a. delaying and comparing means for deriving From the intensity signal a control signal whose amplitude gradually increases prior to the transition, peaks sharply at the center of the transition, and gradually decreases after the transition, and whose sign is determined by the direction of the transition; and b. means for varying the sweep velocity of the picture scan in accordance with said control signal; c. said delaying and comparing means being so arranged that the peak amplitude and peaking sharpness of said control signal rapidly diminishes as the transition time of an intensity transition in said picture increases beyond said predetermined minimum transition time associated with a sharp edge in said original scene.
Claim 21
Dependent Claim
58 words
Apparatus according to claim 14, further comprising means for amplifying said control signal before using it to vary the sweep velocity of said scan, said amplifying means having a response curve such as to amplify higher control signal levels substantially more than lower control signal levels, whereby transitions involving small intensity changes such as noise remain substantially unenhanced.
References Cited (Backward Citations)
US3479453A
Cited
US3536826A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |