GB701884A - Gamma control apparatus - Google Patents
Gamma control apparatusInfo
- Publication number
- GB701884A GB701884A GB10805/52A GB1080552A GB701884A GB 701884 A GB701884 A GB 701884A GB 10805/52 A GB10805/52 A GB 10805/52A GB 1080552 A GB1080552 A GB 1080552A GB 701884 A GB701884 A GB 701884A
- Authority
- GB
- United Kingdom
- Prior art keywords
- scanning
- control
- photo
- contrast
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000004048 modification Effects 0.000 abstract 3
- 238000012986 modification Methods 0.000 abstract 3
- 230000003287 optical effect Effects 0.000 abstract 3
- 230000000694 effects Effects 0.000 abstract 2
- 238000000926 separation method Methods 0.000 abstract 2
- 238000010894 electron beam technology Methods 0.000 abstract 1
- 238000000034 method Methods 0.000 abstract 1
- 230000001360 synchronised effect Effects 0.000 abstract 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/30—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical otherwise than with constant velocity or otherwise than in pattern formed by unidirectional, straight, substantially horizontal or vertical lines
- H04N3/34—Elemental scanning area oscillated rapidly in direction transverse to main scanning direction
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/80—Camera processing pipelines; Components thereof
- H04N23/82—Camera processing pipelines; Components thereof for controlling camera response irrespective of the scene brightness, e.g. gamma correction
- H04N23/83—Camera processing pipelines; Components thereof for controlling camera response irrespective of the scene brightness, e.g. gamma correction specially adapted for colour signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/14—Picture signal circuitry for video frequency region
- H04N5/20—Circuitry for controlling amplitude response
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/11—Scanning of colour motion picture films, e.g. for telecine
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Projection-Type Copiers In General (AREA)
Abstract
701,884. Copying telegraphy; television. RADIO CORPORATION OF AMERICA. April 29, 1952 [May 1, 1951], No. 10805/52. Class 40 (3). [Also in Group XL(c)] In a copying-telegraphy (i.e. colour printing or television transmitter, the scanning apparatus comprises means for scanning successive areas of the subject which are sufficiently small to resolve a desired amount of detail and further scanning means, synchronized with the first scanning means, which scans the subject without resolving the same amount of detail ; the signals derived from the second scanning means being used to effect "gamma" or contrast control of the signals derived from the first scanning means. The control signals are used to reduce the contrast in large areas of the picture ; however, due to the lack of small-area definition in the control signals, the contrast in small areas of the picture is not reduced. Copying-telegraphy.-Fig. 1 illustrates a colourprinting system employing three colour-separation transparencies 10, 20 and 30 and a further transparency 36 representing brightness. A scanning raster on the screen of a cathode-ray tube 2 is focused on each of the transparencies by means of suitable optical systems including partially silvered mirrors 4, 12 and 28, the caster however being but imperfectly focused on the transparencies 36 so that the signals generated in photo-cell 40 correspond to a lower definition than those generated in photo-cells 16, 26, 34. The control signal generated in the photo-cell 40 may be used in either of two ways ; it may either be applied via a non-linear amplifier 44 to control the responses of the photo-cells 16, 26 and 34, or it may be applied via a second non-linear amplifier 46 to control the brilliance of the raster on the screen of the cathode-ray tube. In a modification, Fig. 6 (not shown), a single colour transparency is used together with one representing brightness, the colour separation being effected by a suitable optical system including dichroic mirrors. Television.-In a film-scanning system employing flying-spot scanning a sharply focused image of the scanning spot is produced in the film gate 104, Fig. 7, and a corresponding signal is developed in the photo-cell 108. An out-offocus image of the scanning spot is produced in the film gate 114 and the corresponding signal developed in the photo-cell 120 is used to effect contrast control. This control may be achieved by applying the output from photo-cell 120 either via non-linear amplifier 124 to control the response of the photo-cell 108 or via non-linear amplifier 126 to control the brilliance of the spot on the screen of the cathode-ray tube. The flying-spot scanner may scan a full raster on the screen of the cathode-ray tube 100, the film being moved intermittently, or it may scan a single line on the tube in which case the film is moved continuously. In a modification, Fig. 8 (not shown), both scanning processes are effected within the same film-gate, an optical system being provided to cause the two rasters to be projected on the film-gate from slightly different directions. In a further modification, Fig. 9, employing two camera tubes, the image produced on camera tube 166 is scanned by a de-focused electron beam and the output from the tube is applied through a non-linear amplifier to a gain control device 162 controlling the amplitude of the output signals from the tube 160. Should the invention be applied to systems employing films or transparencies which have been so treated as to reduce their contrast range, further non-linear amplifiers, as indicated by the dotted rectangles in Figs. 1, 7 and 9, may be provided to compensate for the further reduction in contrast provided by the invention thus restoring the large-area contrast to its value in the film or transparency and increasing the contrast in the detail above its original value.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US304909XA | 1951-05-01 | 1951-05-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB701884A true GB701884A (en) | 1954-01-06 |
Family
ID=21854445
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB10805/52A Expired GB701884A (en) | 1951-05-01 | 1952-04-29 | Gamma control apparatus |
Country Status (4)
Country | Link |
---|---|
BE (1) | BE511089A (en) |
CH (1) | CH304909A (en) |
FR (1) | FR1059081A (en) |
GB (1) | GB701884A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2985065A (en) * | 1957-03-15 | 1961-05-23 | Rca Corp | Composite photography |
US2985064A (en) * | 1957-03-15 | 1961-05-23 | Rca Corp | Composite photography |
US3037422A (en) * | 1957-03-15 | 1962-06-05 | Rca Corp | Composite photography |
US3041932A (en) * | 1957-09-24 | 1962-07-03 | Hunter Penrose Ltd | Photographic colour reproduction apparatus |
US3270611A (en) * | 1961-08-24 | 1966-09-06 | Ibm | Apparatus for monitoring relative contrast |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2911468A (en) * | 1958-01-24 | 1959-11-03 | Gen Precision Lab Inc | Video resolution control |
FR77955E (en) * | 1959-10-27 | 1962-05-18 | Electronique & Physique | Improvements in gamma correction processes in television and equipment for this purpose |
GB1057253A (en) * | 1962-11-09 | 1967-02-01 | Emi Ltd | Improvements relating to television camera arrangements |
FR2967153B1 (en) | 2010-11-04 | 2014-10-03 | Solvay | PROCESS FOR THE TREATMENT OF WASTEWATER FROM THE PREPARATION OF A HALOGEN POLYMER |
-
0
- BE BE511089D patent/BE511089A/xx unknown
-
1952
- 1952-04-22 FR FR1059081D patent/FR1059081A/en not_active Expired
- 1952-04-29 GB GB10805/52A patent/GB701884A/en not_active Expired
- 1952-04-30 CH CH304909D patent/CH304909A/en unknown
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2985065A (en) * | 1957-03-15 | 1961-05-23 | Rca Corp | Composite photography |
US2985064A (en) * | 1957-03-15 | 1961-05-23 | Rca Corp | Composite photography |
US3037422A (en) * | 1957-03-15 | 1962-06-05 | Rca Corp | Composite photography |
US3041932A (en) * | 1957-09-24 | 1962-07-03 | Hunter Penrose Ltd | Photographic colour reproduction apparatus |
US3270611A (en) * | 1961-08-24 | 1966-09-06 | Ibm | Apparatus for monitoring relative contrast |
Also Published As
Publication number | Publication date |
---|---|
FR1059081A (en) | 1954-03-22 |
CH304909A (en) | 1955-01-31 |
BE511089A (en) |
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