US2218498A - Telecine system - Google Patents

Telecine system Download PDF

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Publication number
US2218498A
US2218498A US174122A US17412237A US2218498A US 2218498 A US2218498 A US 2218498A US 174122 A US174122 A US 174122A US 17412237 A US17412237 A US 17412237A US 2218498 A US2218498 A US 2218498A
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United States
Prior art keywords
film
image
frame
scanning
prism
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Expired - Lifetime
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US174122A
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English (en)
Inventor
Bunger Walter
Kosche Erich
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FIRM OF FERNSEH AG
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FIRM OF FERNSEH AG
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    • 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
    • H04N3/36—Scanning of motion picture films, e.g. for telecine
    • H04N3/38—Scanning of motion picture films, e.g. for telecine with continuously moving film
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B35/00—Stereoscopic photography
    • G03B35/08—Stereoscopic photography by simultaneous recording
    • G03B35/10—Stereoscopic photography by simultaneous recording having single camera with stereoscopic-base-defining system
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output
    • H01J31/42—Image pick-up tubes having an input of visible light and electric output with image screen generating a composite electron beam which is deflected as a whole past a stationary probe to simulate a scanning effect, e.g. Farnsworth pick-up tube

Definitions

  • This invention relates to a method of and to devices for scanning films by means ofcathode ray tubes particularly of the dissector type. While standard sound film projectors are operated with 5 24 or 25 frames per second, it is desirable to use a higher field frequency in television in order to avoid flicker. This increasein the rate of scanning is not difiicult when a mechanical scanner is used. There are, however, great difficulties when aninterlaced scanning method is used, operating on a purely electrical principle.
  • Another method of scanning uses a continuously moving film and the movement of the film is compensated by the electric movement, for example by using a dissector-type tube with a fixed scanning aperture.
  • Such a method requires three deflection frequencies, namely the transverse or high scanning frequency, the field frequency, for example 50 cycles per second, and a frequency equal to half the field frequency in a single interlace; usually called the repetition frequency.
  • a third method the image moving across the photoelectric cathode with uniform speed is scanned by a ray moving in the opposite direction in order to produce the necessary rate of scanning. If, for example, 25 frames per second are on the film and if the scanning ray is moved with a frequency of 25 cycles per second against the movement of the image, each frame is scanned twice.
  • This method has the drawback that the amplitude of the repetition frequency must be kept very nearly constant in order to obtain a correct interlace.
  • the first frame of the film is scanned during the first part of the deflection period, that is, during the first second.
  • the scanning of the second picture follows without interrupting the scanning deflection.
  • Fig. 1 shows in heavy lines the two frames at andb. The contents of the two pictures are, an oblique line ,c.
  • the scanning frequency is the field frequency and not therepetition frequency;
  • the electrical scanning has an amplitude corresponding to 1/12 height of the frame while the frequency is equal to n times the repetition frequency.
  • This method has the advantage that the requirements forthe electricallrelaxation generatorwlth regard to the exactness of the amplitude are lower because-the exactness of the interlace depends only on optical and mechanical adjustments. This optical adjustment is much easier to carry out than the electrical control. Besides it is possible to use a continuously moving film even in case subsequent frames are scanned a different number of times.
  • Figs. 3 and 4 are schematic showings of the elements of a projection system containing a double prism and a rotating shutter;
  • Fig. 5 shows the shutter disc in front View
  • Fig. 6 is a showing of a particularly useful arrangement containing as television analyzer a dissector tubeand representing the lateral displacement of the light rays;
  • Fig. '7 shows another form of the shutter disc
  • Fig. 8 indicates the scanning principle
  • Fig. 9 shows an arrangement in which alternating frames are scanned a different number of times.
  • the film l of Figs. 3 and l moves continuously in the direction of the arrow through the gate 2 and is reproduced on the light-sensitive layer 3' of the analyzer 4.
  • a double prism 6 is arranged behind an objective 5 dividing the frame picture into two laterally displaced images on the photoelectric cathode.
  • a shutter disc I is rotated in front of the double prism and exposes alternatively one or the other prism. It is assumed that a film with 25 frames per second is used for a transmission with 50 fields per second of 200 lines each.
  • Fig. 3 shows the position of a frame at the beginning and at the end of second
  • Fig. 4 shows the position of the next frame at the beginning and at the end of the following second.
  • the frame positioned in the gate at the beginning of the scanning movement is represented by the arrow 8.
  • the arrow 9 shows the image of the frame.
  • the frame is moving into position l0 so that the'image is moving into position I l.
  • the scanning ray is moving from position l2 into position l3 so that it is moving in a direction opposite that of the image of the frame.
  • the shutter 1 has exposed the upper prism 6.
  • the shutter disc 1 exposes the lower prism and covers the upper prism.
  • the following part of the movement is represented in Fig. 4.
  • the image of the next frame I4 is indicated by arrow l5 and is scanned by ray [2 while it is moving into the position l6 during second. At the end of the stroke the next frame has reached position I! in the gate 2. This frame is scanned a second time in the same manner as the frame indicated by the arrow 8,.so that each frame is scanned twice. If an odd-line interlace is used, the two images must be displaced for exactly onehalf of the frame height; if an even-line interlace is used, the displacement must be equal to one-half the height of a frame plus one-half of the width of a line.
  • the exact adjustment of the images is produced by an adjustment of one or both prisms. The whole prism arrangement or only one of the prisms is mounted on an adjustment device in order to permit exact positioning.
  • the relaxation oscillator frequencies remain unchanged and may have an integral or non-integral ratio to one another.
  • the shutter disc is represented in Fig. 5.
  • the double prism 6 is indicated as a rectangle of which only one-half is exposed by the slots l8 and I9 alternatively.
  • the circumference of the disc is dependent on the fact that the change from one prism to the next one shall not take a longer time than the return movement of the cathode ray, that is, 5 to 10% of the scanning period.
  • Half the circumference of the circle 2! must therefore be at least 10 times as long as the distance 22.
  • the disc is rotated in the present case at 1500 revolutions per minute.
  • an optical arrangement for instance a reflecting prism or a mirror arrangement, can be used for producing not only an overlapping of the images but also a lateral displacement or shifting of the light rays.
  • the lateral displacement of the rays is used to avoid an interference of the electrode system with the light rays.
  • FIG. 6 An embodiment of this kind is represented in Fig. 6.
  • the image of the frame is split up by a double prism 23, producing a lateral shifting of the light rays.
  • the prism has the general form of a plane-parallel prism.
  • the prism is adjustably mounted and both parts of the prism can be moved relatively to one another so that the images produced on the photoelectric cathode can be adjusted exactly for the fraction of a line width.
  • Such a prism arrangement is disclosed and claimed in our copending application Serial No. 189,010, filed February 5, 1938.
  • the electrode system 24 of the dissector tube 26 is situated perpendicularly to the plane of the drawing outside of the path of the light rays.
  • the synchronism between the film and the shutter disc can be obtained by a mechanical drive common to both devices or by separate driving means fed from the same mains.
  • the phasing is obtained by an adjusting device 2'! arranged between the motor 30 of the disc and the driving mechanism 3
  • an adjusting device 28 is provided in order to adjust the phase of the relaxation oscillator 29 in relation to the film drive.
  • the adjusting device may consist for instance of a motor, the stator of which is adjustable.
  • the oscillator 29 is fed from the same mains as the motor.
  • the film frame may be reproduced on the photo-cathode with a relation of 1:1 or preferably on an enlarged scale.
  • the rotating shutter it is also possible to use a movable prism changing its position for each of a second. It is also possible to use a movable mirror or a rotating ring prism.
  • a shutter moving closely adjacent to the film gate or in the plane of an intermediate optical image of the film frame.
  • Such a device is represented in Figs. '7 and 8. It is assumed that, in Fig. 8, the scanning ray 45 is scanning line 46.
  • a part 4'! of the frame is covered by the shutter 38 so that the shaded parts of the overlapping pictures represented by arrows 43 and 44 are not reproduced on the photoelectric layer.
  • Each sector 39 of the shutter disc 38, in Fig. '7 must move across the gate during the time of a picture repetition, so that the relation between the scanned line and the covered part of the frame is maintained.
  • the cone-shaped form of the shutter disc 38 represented in Fig. '7 has the advantages that the device can more easily be arranged nearer the film gate, that the movement of the single sectors 39 is more easily kept parallel to the moveaarsncs ment. ofthe and thatthe sectors 39..have approximately rectangular form-even-when the disc has a small diameter. Instead 'ofthe disc 38 a spiral shutter maybe used coveringalways the part of the picture which is not being scanned.
  • the optical arrangement corresponds otherwise to that of the foregoing figures, having the source of light 31, a condenser lens 36,'the mm 35, the objective 4!], the prism arrangement M and thephotoelectric cathode 42.
  • the arrangement of the shutter closely adjacent the gate is preferable because it is possible to use a disc of smaller diameter in comparison with the arrangement of Figs. 3 and 4, on account of the small size of the film frames.
  • the scanning movement must be opposite to the movement of the film and equal to of the height of the image.
  • the scanning takes place with a frequency of 60 cycles per second, and the scanning amplitude equals the height of the image.
  • each alternate frame is scanned three times and the frames in between two times.
  • the movement of the film is accounted for by an optical system in the following manner.
  • the first frame of the fllrn may have the position of the arrow IBM. Its image appears at arrow Ill when the ratio of reproduction is 1:1.
  • the image is moved downwardly by means of a prism IZI from the situation Ill so that the point of the arrow (the edge of the image) is situated on the line Hi6,
  • the shutter disc I has such a position that the light traversing the objective 5 can pass through the prism l2! only'during the first 4 second while all other prisms are covered.
  • the prism shifts the image downwardly for of its height.
  • the scanning movement reaches the position I I3 at the end of the first second.
  • the film frame moves into position I02 when the scanning movement is making the return stroke.
  • the image is produced without the use of a prism through the central part of the arrangement.
  • the image is represented by arrow H2.
  • prism It? acts to move image H3 upwardly for of the height of the image. .At the end of the third 4 second, thenext frame of the film. is reproduced, having reached the position I04.
  • the first frame is represented by the dotted line NM.
  • the image lid of the second frame is moved downwardly by prism [24 for /5 of the height and scanned during the fourth second.
  • the second frame having first the position I 95, is scanned again. Its image H5 is moved upwardly by prism E25 for of the height of the image. After the fifth 4 second, the third frame is scanned in the same manner as frame MI.
  • the film gate has a height of .the height of the frame.
  • the prisms represented in Fig. 9 it is preferable to usean arrangement of prisms according to Fig. 6. These prisms have the advantage of producing less distortion.
  • a shutter stead of the disc 1 a shutter, accordingto Fig. 7, may be used.
  • the method has the advantage that the film is moving continuously past the window so that the necessity of a swiftintermediate movement is avoided.
  • a cathode ray device comprising an envelope having a photoelectric cathode disposed therein at one end and a pencillikev anode disposed therein at an opposite end,
  • a cathode ray device comprising an envelope having a photoelectric cathode and a pencil-like anode, both located on the longitudinal axis of said envelope, means external to said device but located on said axis in line with said anode and said cathode for producing an optical image, and a prism located intermediate said optical image producing means and said anode to intercept an optical image from said optical image producing means and deflect the entire intercepted image around said anode onto said cathode, whereby said anode will not cast a shadow on said cathode.
  • a cathode ray device comprising an envelope having a screen at one end and a pencil-like electrode at the other end, means for directing a beam of light in line with said electrode and said screen and means for bending said beam about said electrode to preclude casting of a shadow of said electrode on said screen, said means comprising a prism having an incident surface substantially normal to the direction of incident light, an emerging surface substantially parallel to said incident surface but laterally offset with respect thereto, and light reflecting surfaces joining corresponding edges of said incident and emerging surfaces at an angle with the normal between said incident and emerging surfaces.
  • a cathode ray device comprising an envelope having a photo-electric cathode at one end thereof and a pencil-like electrode at the opposite end of said device, means for directing a pair of optical images of a subject, on said cathode from a point'external to said device and in line with said electrode and cathode, without casting'a shadow of said electrode on said screen, said means including a pair of prisms substantially symmetrically disposed with respect to said electrode, each prism having substantially vertical incident and emerging surfaces and light reflecting surfaces joining said vertical surfaces at an angle to the normal between said vertical surfaces to cause an incident ray to emerge in a direction to miss said electrode and strike said cathode, said prisms being spaced to cast overlapping images on said cathode offset with respect to each other by at least half scanning line thickness, and means for alternately intercepting the light through one prism and then the other.
  • means for two-dimensional scanning at a repetition frequency greater than the normal frame frequency of the film which comprises means for optically deflecting the image of said film frames in the direction of film travel, means for optically deflecting the image of said film frames in a direction opposite to that of the film travel, and means for obturating said deflecting means alternately in synchronism with the movement of said film.
  • means for deflecting a portion of successive images on said film in the direction of film travel, and means for deflecting a portion of said film images in a direction opposite to that of film travel comprising a plurality of prisms positioned to deflect light passing therethrough, said prisms being adjusted to provide deflections in opposite directions differing by half the width between successive scanning lines, and means for alternately obturating said deflecting means.
  • Means for scanning motion-picture film associated with television apparatus comprising a source of projection light, means for focusing said projection light to form an optical image of said film, means for displacing said image in the same direction as that of travel of film to be televised, means for displacing said image in a direction opposite to the direction of travel of said film, an obturating shutter arranged to sequentially and alternately cover and uncover said light-deflecting means, and means' for transforming an optical image into television signals.
  • the method of two-dimensional scanning at a repetition frequency greater than the normal frame frequency of the film which comprises the steps of optically deflecting the image of said film frames in the direction of film travel,
  • the method of two-dimensional scanning at a repetition frequency greater than the normal frame frequency of the film which comprises the steps of prismatically deflecting the image of said film frames in the direction of film travel, prismatically deflecting the image of said film frames in a direction opposite to that of the film travel, and obturating said deflected images alternately in synchronism with the movement of said film.
  • a moving-picture projector for television use, the method which comprises focusing light from a source to form an optical image of the film to be televised, displacing said image in a direction opposite to the direction of travel of said film, sequentially and alternately intercepting said displaced images, and transforming said images into television signals.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Details Of Television Scanning (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Microscoopes, Condenser (AREA)
  • Studio Devices (AREA)
US174122A 1936-11-12 1937-11-11 Telecine system Expired - Lifetime US2218498A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE202379X 1936-11-12
DE60237X 1937-02-06

Publications (1)

Publication Number Publication Date
US2218498A true US2218498A (en) 1940-10-15

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ID=25749285

Family Applications (2)

Application Number Title Priority Date Filing Date
US174122A Expired - Lifetime US2218498A (en) 1936-11-12 1937-11-11 Telecine system
US189010A Expired - Lifetime US2265264A (en) 1936-11-12 1938-02-05 Prism arrangement for producing double images, particularly for television purposes

Family Applications After (1)

Application Number Title Priority Date Filing Date
US189010A Expired - Lifetime US2265264A (en) 1936-11-12 1938-02-05 Prism arrangement for producing double images, particularly for television purposes

Country Status (6)

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US (2) US2218498A (es)
BE (1) BE424562A (es)
CH (1) CH202379A (es)
FR (1) FR829035A (es)
GB (1) GB505574A (es)
NL (1) NL60010C (es)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2590281A (en) * 1948-08-13 1952-03-25 Rca Corp Television film scanner
US3198067A (en) * 1962-04-12 1965-08-03 Columbia Broadcasting Syst Inc Optical recording-reproducing scanning system

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2701503A (en) * 1952-01-21 1955-02-08 Calvi Pericles Production of parallax panoramagrams
US2882782A (en) * 1953-11-06 1959-04-21 Earl M Welch Photography and projection apparatus
DE9013557U1 (de) * 1990-09-27 1990-12-06 Mesacon Gesellschaft für Meßtechnik mbH, 44227 Dortmund Optisches Gerät, insbesondere zur Messung der Geschwindigkeit einer bewegten Oberfläche mittels eines von einem Laser ausgehenden Meßlichtstrahls
GB2281166B (en) * 1993-08-16 1997-08-06 Rank Cintel Ltd Telecines

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2590281A (en) * 1948-08-13 1952-03-25 Rca Corp Television film scanner
US3198067A (en) * 1962-04-12 1965-08-03 Columbia Broadcasting Syst Inc Optical recording-reproducing scanning system

Also Published As

Publication number Publication date
BE424562A (es)
FR829035A (fr) 1938-06-08
NL60010C (es)
CH202379A (de) 1939-01-15
GB505574A (en) 1939-05-12
US2265264A (en) 1941-12-09

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