Patent US4766503A successfully refreshed from Google Patents.
US4766503A
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US
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Color film writing system with closed loop control for electronic images
Assignee: General Electric Co
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Filing: 1986-07-21
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Granted: 1988-08-23
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Expires: 2006-07-21
Abstract
Abstract An imaging system for generating a color image on film from electronic video image data incorporates feedback control techniques to provide control of film density. The system includes variable gain amplifiers responsive to light intensity output of a film writing device for maintaining the output at a desired set level. In addition, the system includes apparatus and a method for monitoring the density of film images produced by the system and for utilizing the monitored values to modify the system transfer function in a direction to effect a change in the film density towards a desired value.
Inventors
- 👤 Thomas W. Lambert
- 👤 Barry F. Belanger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:01
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/72; H04N1/00; H04N1/40; H04N1/407; H04N1/4076; H04N1/4078; H04N5/76; H04N5/84; H04N5/87; H04N9/00; H04N9/79; H04N9/80; H04N9/82
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
196 words
In an imaging system for generating an image on film from electronic image data, the system including a plurality of controllable transfer devices, each of said devices controlling image data corresponding to one of a plurality of regions of the light spectrum, a method for controlling film density comprising the steps of: providing at least one film writing device having a predetermined light intensity output in response to a predetermined input command signal amplitude; generating for each of the regions of the light spectrum an input command signal having an amplitude varying as a function of position of a light beam from the film writing device whereby the light intensity output varies in correspondence with beam position; exposing a film to the light output from the film writing device; developing the exposed film; reading the image density on the film for each of the plurality of regions of the light spectrum using the film writing device; adjusting each of the controllable transfer devices to correct for deviations in film density from a desired value; and repeating the steps of generating, exposing, developing, reading and adjusting until a film image is obtained having the desired density value.
Claim 2
Dependent Claim
196 words
In an imaging system for generating an image on film from electronic image data, the system including a plurality of controllable transfer devices, each of said devices controlling image data corresponding to one of a plurality of regions of the light spectrum, a method for controlling film density comprising the steps of: providing at least one film writing device having a predetermined light intensity output in response to a predetermined input command signal amplitude; generating for each of the regions of the light spectrum an input command signal having an amplitude varying as a function of position of a light beam from the film writing device whereby the light intensity output varies in correspondence with beam position; exposing a film to the light output from the film writing device; developing the exposed film; reading the image density on the film for each of the plurality of regions of the light spectrum using the film writing device; adjusting each of the controllable transfer devices to correct for deviations in film density from a desired value; and repeating the steps of generating, exposing, developing, reading and adjusting until a film image is obtained having the desired density value.
Claim 3
Dependent Claim
98 words
The method of claim 1 wherein said step of reading the image density on the film comprises the further steps of: generating a light beam of uniform intensity; scanning the generated light beam through a neutral density sensitometric block; detecting the light beam passing through the sensitometric block with a photodetector; calibrating the photodetector to produce output signals corresponding to the grey scale values of the sensitometric block based upon the light beam passing therethrough; scanning the generated light beam through the exposed film; and reading the film density with the calibrated photodetectors to produce film density signals.
Claim 4
Dependent Claim
39 words
The method of claim 2 wherein the film density signals developed by the photodetector during the film reading step are applied to corresponding ones of the transfer devices to modify its transfer characteristic to compensate for film density deviations.
Claim 5
Dependent Claim
72 words
The method of claim 1 wherein said step of providing at least one film writing device having a predetermined light intensity output comprises the substeps of: driving the at least one film writing device with a signal having a predetermined value through a first controllable gain amplifier; measuring the light intensity output of the film writing device; and adjusting the gain of the first amplifier to force the predetermined light intensity output.
Claim 6
Dependent Claim
45 words
The method of claim 4 and including the further steps of: measuring the minimum light intensity output of the at least one film writing device; and setting the amplitude of bias voltage applied to the device such that a desired minimum light intensity is achieved.
Claim 7
Dependent Claim
184 words
A color film imaging system for generating a color image on film from electronic image data, the color image being formed by film exposure to light created by a combination of a plurality of different color light beams having a controlled intensity, the system comprising: at least one film writing device for providing a controllable light intensity output in response to at least one of a plurality of write intensity input signals, each of said signals representative of the different color light beams; means for exposing the film to the light output of said device; means for developing the exposed film; means for determining the film density of the developed film using light output from said film writing device and for generating a signal representative of the film density for each different color light beam; and means responsive to said film density representative signal for varying the write intensity input signal in a manner to adjust the light intensity output corresponding to each of the different color light beams to compensate in subsequent film exposures for deviations in film density from a desired level.
Claim 8
Dependent Claim
184 words
A color film imaging system for generating a color image on film from electronic image data, the color image being formed by film exposure to light created by a combination of a plurality of different color light beams having a controlled intensity, the system comprising: at least one film writing device for providing a controllable light intensity output in response to at least one of a plurality of write intensity input signals, each of said signals representative of the different color light beams; means for exposing the film to the light output of said device; means for developing the exposed film; means for determining the film density of the developed film using light output from said film writing device and for generating a signal representative of the film density for each different color light beam; and means responsive to said film density representative signal for varying the write intensity input signal in a manner to adjust the light intensity output corresponding to each of the different color light beams to compensate in subsequent film exposures for deviations in film density from a desired level.
Claim 9
Dependent Claim
136 words
The control system of claim 6 wherein said at least one film writing device comprises: a controllable light source; at least one variable gain amplifier having an input terminal for receiving at least one of the plurality of write intensity input signals and an output terminal for providing a drive signal to said light source, and further including a first control terminal for receiving a gain control signal; means for monitoring the light intensity output of said light source, said monitoring means providing a signal representative of the intensity of light output from said light source; and means coupling said light intensity representative signal to said amplifier control terminal for selectively varying the gain of said amplifier in a direction to provide a predetermined light intensity output in response to a predetermined magnitude of input signal.
Claim 10
Dependent Claim
98 words
The control system of claim 6 wherein said means responsive to said film density representative signal comprises a controllable transfer device for image data corresponding to each of the color light beams, each device having a data input signal terminal, a data output terminal and a control terminal, each said transfer device operating on the image data applied to said input terminal to provide an output signal at said data output terminal having a determinable relationship to the image data, said determinable relationship being variable in response to said film density representative signal applied to said control terminal.
Claim 11
Dependent Claim
17 words
The control system of claim 8 wherein each said transfer device comprises a variable gain analog amplifier.
Claim 12
Dependent Claim
51 words
The control system of claim 8 wherein each said transfer device comprises a digital memory device having a plurality of light intensity values stored in a look-up table format, the image data being formatted as an address to effect readout of selected stored values in response to the corresponding image data.
Claim 13
Dependent Claim
87 words
The control system of claim 7 wherein said at least one amplifier includes a second control terminal, said amplifier being arranged to have a variable zero offset in response to a signal applied to said second control terminal, said control system including: means for determining minimum light intensity output of said film writing device and for producing a signal representative thereof; and means for coupling said minimum intensity signal to said second control terminal whereby said amplifier offset is adjusted to provide a desired minimum light intensity.
Claim 14
Dependent Claim
79 words
The control system of claim 7 wherein said at least one amplifier comprises: a first variable gain linear amplifier providing an output signal proportional to a corresponding one of the write intensity input signals, the proportional relationship being variable in response to said light intensity representative signal; and a second linear amplifier having a predetermined fixed gain and an adjustable minimum output signal, said second amplifier including said second control terminal for effecting adjustment of said minimum output signal.
Claim 15
Dependent Claim
51 words
The control system of claim 12 wherein said means for monitoring the light intensity output comprises a light sensing device connected in a light path of said light source, said light sensing device providing an output signal proportional to the light output of said light source adjacent said light sensing device.
Claim 16
Dependent Claim
75 words
The control system of claim 13 wherein said means coupling said light intensity representative signal to said amplifier control terminal comprises: means for selectively sampling the output signal from said light sensing device; means for comparing said sampled output signal to a predetermined reference signal and for providing a summation signal representative of the difference therebetween; means for storing said summation signal; and means for applying said stored summation signal to said first control terminal.
Claim 17
Dependent Claim
51 words
The control system of claim 11 wherein said means for determining minimum light intensity output comprises a light sensing device connected in a light path of said light source, said light sensing device providing an output signal proportional to the light output of said light source adjacent said light sensing device.
Claim 18
Dependent Claim
69 words
The control system of claim 15 wherein said means for coupling said minimum intensity signal comprises: means for selectively sampling the output signal from said light sensing device; means for comparing said sampled signal to a predetermined reference signal and for providing a summation signal representative of the difference therebetween; means for storing said summation signal; and means for applying said stored summation signal to said second control terminal.
Claim 19
Dependent Claim
44 words
The control system of claim 16 wherein said means for applying said stored summation signal comprises a clamp circuit synchronized to a standard video wave form such that said minimum intensity level is set only when said video signal is at corresponding minimum level.
Claim 20
Dependent Claim
16 words
The control system of claim 7 wherein said coupling means includes said film density responsive means.
Claim 21
Dependent Claim
84 words
The control system of claim 18 wherein said film density responsive means comprises a plurality of variable offset proportional plus integral signal transfer devices, each device processing image data representative of one of the color light beams, each device having a signal input terminal for receiving a signal representative of the difference between an intensity reference signal and said light intensity representative signal and further including a control terminal for receiving said film density representative signal for varying said difference signal in proportion thereto.
Claim 22
Dependent Claim
46 words
The control system of claim 7 wherein said monitoring means includes a first photodetecting sensor for monitoring light output of said light source at a first minimum level and a second photodetecting sensor for monitoring light output of said light source at a second maximum level.
Claim 23
Dependent Claim
34 words
The control system of claim 7 wherein said coupling means includes a first control loop for adjusting the minimum light intensity output and a second control loop for adjusting the maximum light intensity output.
Claim 24
Dependent Claim
15 words
The imaging system of claim 6 wherein said film writing device comprises a color monitor.
Claim 25
Dependent Claim
53 words
The imaging system of claim 6 wherein said film writing device comprises a monochrome monitor, the color image being obtained by time sequential exposure of the film to the monitor through a light filter having a color corresponding to the color associated with the image data driving the monitor during each time sequence.
Claim 26
Dependent Claim
58 words
The imaging system of claim 6 wherein said film writing device comprises a plurality of monochrome monitors, each monitor being driven by image data corresponding to one of the color light beams and each monitor having a light filter corresponding to one of the associated color light beams, the film being sequentially exposed to light from each monitor.
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) | 1991-08-23 | 1992-02-22 | 1992-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-23 | 1996-02-22 | 1996-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-23 | 2000-02-22 | 2000-08-23 | $7700.00 | Window Closed / Lapsed |