Patent EP0230361A2 successfully refreshed from Google Patents.
EP0230361A2
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EP
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System and method for adjusting image brightness in electronic printer
Assignee: Polaroid Corp
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Filing: 1987-01-09
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Granted: —
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Expires: 2007-01-09
Abstract
Abstract A system and method for displaying an image for photographic reproduction operates to calibrate the brightness of the image display prior to each photographic reproduction in a manner that accounts for the variations in the brightness characteristics of the images of different scenes to be photographically reproduced.
Inventors
- 👤 Guillermo S. Ferla
- 👤 Dean Gross
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 12:28
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40025; H04N1/4005; H04N1/407
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
255 words
An electronic printer for displaying an image for photographic reproduction, the printer comprising display means (14) for visually displaying the image to be photographed; photoresponsive means (26) for detecting the intensity of light emanating from the display means and providing an output signal corresponding to the intensity of light so detected; comparator means (30) for comparing the output signal from the photoresponsive means (26) with a select one of a plurality of different voltage reference signals and providing an output signal indicative of the comparison; and control means (24,32,34,36) for initially applying a steady state select voltage (V REP ) to the display means (14) in place of an image defining electronic information signal so that the display means displays a substantially uniform light intensity; for thereafter adjusting, if necessary, the light intensity of the display means (14) in response to the output of the comparator means (30) so that the light intensity of the display means corresponds to the one select voltage reference signal; for thereafter applying an image defining electronic information signal (VIDEO) in place of the steady state select voltage to the display means (14) so that the display means displays the image to be photographed; for thereafter selecting, if necessary, other ones of the plurality of different voltage reference signals until the ouput signal from the comparator means (30) meets a select condition; and for thereafter adjusting, if necessary, the light intensity of the display means as a function of the different voltage reference signals selected in the immediately preceding step.
Claim 2
Dependent Claim
255 words
An electronic printer for displaying an image for photographic reproduction, the printer comprising display means (14) for visually displaying the image to be photographed; photoresponsive means (26) for detecting the intensity of light emanating from the display means and providing an output signal corresponding to the intensity of light so detected; comparator means (30) for comparing the output signal from the photoresponsive means (26) with a select one of a plurality of different voltage reference signals and providing an output signal indicative of the comparison; and control means (24,32,34,36) for initially applying a steady state select voltage (V REP ) to the display means (14) in place of an image defining electronic information signal so that the display means displays a substantially uniform light intensity; for thereafter adjusting, if necessary, the light intensity of the display means (14) in response to the output of the comparator means (30) so that the light intensity of the display means corresponds to the one select voltage reference signal; for thereafter applying an image defining electronic information signal (VIDEO) in place of the steady state select voltage to the display means (14) so that the display means displays the image to be photographed; for thereafter selecting, if necessary, other ones of the plurality of different voltage reference signals until the ouput signal from the comparator means (30) meets a select condition; and for thereafter adjusting, if necessary, the light intensity of the display means as a function of the different voltage reference signals selected in the immediately preceding step.
Claim 3
Dependent Claim
74 words
An electronic printer according to claim 1, wherein the display means comprises a cathode ray tube (14) having cathode and grid terminals, the control means being adapted to apply the steady state voltage and the image defining electronic information signal to the cathode terminal of the cathode ray tube and to adjust the light intensity of the cathode ray tube by varying the voltage applied to the grid terminal of the cathode ray tube.
Claim 4
Dependent Claim
59 words
An electronic printer according to claim 1 or claim 2, wherein the control means comprises a first plurality of resistors (R₁-R₅) and first switch means (S₁-S₅) for connecting the resistors in select parallel relationship with respect to each other, the switch means being selectively controlled to vary the voltage applied to the grid terminal of the cathode ray tube.
Claim 5
Dependent Claim
54 words
An electronic printer according to claim 3, wherein the control means comprises a second plurality of resistors (R₆,R₇) and a second switch means (S₆,S₇) for connecting the resistors in select parallel relationship with respect to each other, the switch means being selectively controlled to select one of the plurality of different voltage reference signals.
Claim 6
Dependent Claim
43 words
An electronic printer according to any of the preceding claims, wherein the cathode ray tube (14) displays a plurality of succeeding television fields and the control means responds to the output of the comparator means (30) only about the middle of each field.
Claim 7
Dependent Claim
46 words
An electronic printer according to any of the preceding claims, wherein the select condition of the output signal from the comparator means (30) corresponds to the output signal from the photoresponsive means (26) not exceeding the select one of the plurality of different voltage reference signals.
Claim 8
Dependent Claim
18 words
An electronic printer according to any of the preceding claims, wherein the control means includes a microprocessor (34).
Claim 9
Independent Claim
211 words
A method for adjusting the image brightness in a system for displaying images for photographic reproduction, the method comprising the steps of applying a steady state select voltage to an image display device (14) so that the display device displays a generally uniform light intensity; detecting the intensity of light emanating from the display device and providing a first output signal corresponding to the intensity of light so detected; comparing the first output signal with a select one of a plurality of different voltage reference signals and providing a second output signal indicative of the comparison; adjusting, if necessary, the light intensity of the display means (14) in response to the second output signal so that the light intensity of the display means corresponds to the one select voltage reference signal; applying an image defining electronic information signal in place of the steady state select voltage to the display means (14) so that the display means displays the image to be photographed; selecting, if necessary, other ones of the plurality of different voltage reference signals until the second output signal meets a select condition; and adjusting, if necessary, the light intensity of the display means (14) as a function of the different voltage reference signals selected in the immediately preceding step.
Claim 10
Independent Claim
211 words
A method for adjusting the image brightness in a system for displaying images for photographic reproduction, the method comprising the steps of applying a steady state select voltage to an image display device (14) so that the display device displays a generally uniform light intensity; detecting the intensity of light emanating from the display device and providing a first output signal corresponding to the intensity of light so detected; comparing the first output signal with a select one of a plurality of different voltage reference signals and providing a second output signal indicative of the comparison; adjusting, if necessary, the light intensity of the display means (14) in response to the second output signal so that the light intensity of the display means corresponds to the one select voltage reference signal; applying an image defining electronic information signal in place of the steady state select voltage to the display means (14) so that the display means displays the image to be photographed; selecting, if necessary, other ones of the plurality of different voltage reference signals until the second output signal meets a select condition; and adjusting, if necessary, the light intensity of the display means (14) as a function of the different voltage reference signals selected in the immediately preceding step.
Claim 11
Dependent Claim
71 words
A method according to claim 8, wherein the display device comprises a cathode ray tube (14) having cathode and grid terminals, the steady state voltage and the image defining electronic information signal being applied to the cathode terminal of the cathode ray tube and the adjustment to the light intensity of the cathode ray tube being accomplished by varying the voltage applied to the grid terminal of the cathode ray tube.
Claim 12
Dependent Claim
41 words
A method according to claim 9, wherein the grid voltage applied to the grid terminal of the cathode ray tube (14) is varied by switching select ones of a plurality of resistors (R₁-R₅) into parallel relation with respect to each other.
Claim 13
Independent Claim
42 words
A method according to any of claims 8 to 10, wherein the select one of the plurality of different voltage reference signals is selected by switching select ones of a plurality of resistors (R₆,R₇) into parallel relation with respect to each other.
Claim 14
Independent Claim
50 words
A method according to any of claims 8 to 11, wherein the display means (14) displays a plurality of succeeding television fields and the steps conducted in response to the second output signal are timed to respond to the second output signal only about the middle of each said field.
Claim 15
Independent Claim
42 words
A method according to any of claims 8 to 12, wherein the select condition of the second output signal corresponds to the output signal from the photoresponsive means (20) not exceeding the select one of the plurality of different voltage reference signals.
References Cited (Backward Citations)
No citation records indexed.
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