DE2315032C3 - Image display device - Google Patents

Description

The invention relates to a picture display device for optionally moving picture or still picture display

drove in video recording devices with tape-shaped recording media, as specified in the preamble of claim I.

Such image display devices are known (DT-OS 19 57 427, US-PS 36 27 922). With the known

ίο image display devices there is a considerable Operating difficulty is that after switching to still image mode, the tape-shaped recording medium must first be brought into a position by hand in which correct scanning is possible will. In the known picture display devices, however, this is indispensable and then particularly unfortunate.

if the user of the device frequently wants to view still pictures.

The object of the invention is therefore to provide an image reproduction

To create input device for the optional motion picture and still picture operation, when switching from motion picture mode to still picture mode automatically the still picture grid, i.e. the scanning grid for the Still picture mode, the width of which in the direction of film travel; coincides with that of a field, with one Field is brought into congruence. The solution to this problem is given in claim 1. Appropriate Refinements are given in the subclaims.

It can be seen that with such a design, the image display device is automatic and without any influence the operator ensures that the still picture grid with the field to be scanned is brought to congruence. For the operation of such an image display device, the optional allows a moving picture or a still picture operation, it is a considerable simplification of the operation that by simply pressing the switch to the still image mode without any manual tracking of the film tape the still picture grid with the field to be scanned comes to coincide. One such automation is of considerable importance with regard to the achieved simplification of operation.

In the drawing, the invention is illustrated by way of example, namely shows

F i g. 1 is a plan view of a tape-shaped recording medium;

F i g. 2 is a perspective view of a known image display device (EFR);

3 is a view showing the known Image scanning,

F i g. 4 shows a view of a known device for deriving a synchronizing signal from the EVR film,
5 shows a view of the mutual arrangement of the EVR film and scanning raster to explain the known EVR device,

F i g. 6 is a perspective view showing the structure of a tape recording material drive for use in FIG

tiner image display device according to the invention,

7 is a schematic view for explanation In an embodiment of the picture display device »EmäC of the invention,

F i g. 8 is a plan view of the known EV R film;

9 shows a plan view of a tape-shaped recording material according to the invention,

10 shows a plan view of a tape-shaped recording material according to the invention and

F i g. 11 is a plan view of a modified one Embodiment of the tape-shaped recording material according to the invention.

The following is the known EVR device with respect to FIG. 1 to 5 described.

The EVR device (electronic video recording device) is one of the American company. Columbia Broadcasting Corporation (CBS) developed facility. According to this facility, a Television signa! by means of an electron beam recording device (EBR) recorded on a black and white film and the recording as a mother negative for Making copies used; the copy of the film contained in a cassette is stored in a playback device played and the reproduced black and white signal or video color signal is in an ordinary TV receiver made visible.

Fig. 1 shows a typical EVR film. The movie is 8.75 mm wide and has two parallel image recording tracks 1 and 2, which are arranged in sets are. In track 1 the luminance signal is recorded and in track 2 the chrominance or Color signal in a coded form suitable for recording and reproduction. Between A synchronous signal track is provided for both tracks, in which a transparent synchronous signal marking is provided for each field 3 is recorded. These markings are used as the television picture is displayed Vertical sync signal. There are magnetic recording tracks on the opposite edges of the film 4 intended for storing the audio signals.

The so constructed EVR-FiIm is played by passing it at a certain speed through a Film drive of the player is moved therethrough (i.e. 60 fields per second and in the NTSC system in the PAL system 50 fields per second), its surface with a light point scanning tube Raster-scanned is used to achieve luminance and chrominance signals by photo-multipliers.

F i g. Figure 2 shows an embodiment example for the movie drive. In this embodiment, the EVR film is 5 from its cassette 6 at a certain speed by means of a tape drive spindle 7 and a Pressure roller 8 unwound and wound onto a take-up reel 9. A drive motor 10 drives the film drive on. Its torque is transmitted via an endless belt 11 to a flywheel 12 to this and to set the tape drive spindle 7 firmly connected to it in rotation.

A step roller 13 firmly connected to the flywheel 12 also drives a roller roller 15 via a rubber roller 14. The rotation of the roll roller 15 is transmitted to the take-up reel 9 via a friction element 16 in order to set it in rotation. Due to the friction element 16, the film transport can be stopped by simply stopping the rotation of the film cassette 6 and releasing the pressure roller 8 without the drive motor 10 having to be switched off. A magnetic head 17 for reproducing the audio signals is in contact with the running film.

The half-image signals of the film are raster-scanned by a light point tube 18. A scanning raster area 19 is focused on a field area of the film by collecting lenses 20 and 21 and reflection prisms 22 and 23. A raster is thrown through the two lens-prism pairs onto two adjacent fields. The light passing through the respective fields is subjected to an intensity modulation as a function of the luminance and chrominance signals and is introduced into photoelectron multiplier tubes 26 and 27 through optical guides 24 and 25 in order to obtain corresponding electrical reproduction signals

To achieve the synchronous signal, light coming from a light source 28 is passed through an optical fiber 29 routed to the sync signal track. The light passing through the sync mark becomes as synchronous signal light through an optical tube 30 to a photoelectric converter 31, e.g. B. passed a phototransistor so that it is read out as a synchronous signal. This sync signal is called Vertical sync signal is used for the video signal and is also used as a control signal for speed control of the film can be used.

In order to be able to read out the signals by scanning the film fields supplied in the manner described above with a rectangular raster, the raster size on the field area must be twice as large as the field in the field direction, that is, the so-called "jumping scanning system" must be used, in which the scanning light point that just the scanning. subject field follows. The reason for the necessity of a double field length for the vertical raster amplitude goes from FIG. The vertical deflection beginning at the upper part of field 1, which is indicated with an arrow in the film position (a) , reaches the lower part of the same field, which is also indicated with an arrow in the film position ^, after one field period has elapsed.

In order to be able to start the vertical scanning of the next field, the scanning point must now jump back to position (c). Consequently, the vertical raster amplitude must be twice as long as the length of the field, ie the vertical scanning speed must be twice as high as the film speed.

For the sampling of the vertical sync signal, the sync mark is usually in one place provided, which is exactly one field length behind the assigned scanning raster, as in Fig.4 is shown. Theoretically, it can be removed from the grid by a whole multiple of the field length lie, however, the greater the distance, the greater the likelihood that the synchronization by elongation or shrinkage of the film or by fluctuations in the synchronous signal frequency is affected. If you place the sync signal mark exactly next to the assigned one Grid, then there are also many difficulties, such as the mechanical Ai.fMu be Ui e Limitations.

Fig.5 shows in detail the grid position and the Position of the assigned synchro-signal marking The is within the bold rectangular half-image limited shaded area 33 of the

Screen area that is twice as large as the field length in the direction of film travel or the vertical scanning direction. The assigned sync signal area lies on the sync signal track by one field length behind-the-grid. The vertical deflection begins when the vertical sync signal is in this relative position Arrangement is located, then an exact scanning of the fields is possible.

The EVR device enables the above-described reproduction of moving pictures and also has the advantage that any desired field can be stably reproduced as a still picture. Usually a still picture is obtained by stopping the film transport and adjusting the vertical grid size reduced to half the size of the screen when the film is running, d. H. the grid size of a length of a field, so that only a single field is scanned. At this point, that will Vertical sync signal generated from a separate frequency standard, e.g. B. an AC power line or also from a separate oscillator. This enables a single field area to be reproduced as a still picture will. However, the position of the field does not always match the position of the grid or is not always precisely aligned with respect to this. In the case of poor alignment, a so-called would not captured still image arise, which includes two adjacent fields The alignment of the Fields are usually hand-picked while viewing the reproduced still picture operable film transport mechanism made.

However, it is very troublesome to have to realign the position of the fields every time a should be reproduced, especially if you look at still images very often would like. Accordingly, it is desirable that the positions of the fields change each time they are reproduced automatically adjusts a still image.

The image display device according to the invention is shown below described with reference to FIGS. 6 to 11.

1. Field adjustment mechanism according to the invention:

Fig. B shows a field adjustment mechanism according to the invention. So far, as already described, the field adjustment has been achieved by operating a manual film transport mechanism; according to the invention, however, this is done by means of an auxiliary motor 35. The auxiliary motor 35 is put into operation by coupling when the playback mode (for the reproduction of moving images) is switched to the standing mode (for the reproduction of still images), and it is through a field adjustment signal to be described below is stopped. The motor torque is transmitted through reduction gears 36 to 43 to a film cassette 6, which is driven thereby and film 5 is reeled out. This mechanism is - as shown in the drawing - below that of the cassette according to FIG. 2 corresponding cassette 6 arranged. The torque transmission gears 41 and 42 sit on a lever 44 which is rotatable about the rotating shaft of gears 39 and 40. The gears 42 and 43 can be brought into or out of engagement with one another by the pivoting movement of the lever 44. The end of the lever 44 opposite the gears 41 and 42 carries a plunger core coil 45 and is pretensioned by a spring 46. In playback mode, the plunger core coil is not fed or is active or kept in the operating state, so that the lever 44 assumes a position in which it keeps the gearwheel 42 out of engagement with the gearwheel 43 due to the tensile force of the spring 46. When switching from playback mode to standing mode, the plunger core coil is driven under coupling with the switching mode and causes a pivoting movement of the lever 44 against the tensile force of the spring 46, so that the gears 42 and 43 are brought into engagement with one another. As a result, the torque of the auxiliary motor 35 is transmitted to the cassette 6. During the standing operation, the plunger core reel 45 is kept in the active or working state and the pressure roller 8 is kept away from the tape drive spindle 7. If playback is switched back to, the pressure roller 8 comes into engagement with the tape drive spindle 7 via the film 5 and unwinds the film at a predetermined speed.

If, with the structure described, the field is not precisely aligned when switching on in standing mode is, the film is driven by the auxiliary motor 35 with appropriate reduction ratio and with appropriate Speed unwound until the correct alignment of the field is determined; whereupon the auxiliary motor 35 is stopped. In this way an automatic field adjustment can be carried out be achieved. At this point the film unwind speed should not be too slow. The Reduction ratio is such that the film oversize or the film extra advance due to the inertia-based rotation of the auxiliary motor 35 after it has been switched off is sufficient is low.

2. Method of obtaining a control signal for

Controlling the auxiliary engine.
4 ~

The easiest and most practical way to achieve the field adjustment signal is that - as in playback mode - a signal is used which is derived from the vertical synchronizing signal marking on the synchronizing signal track. In other words, after switching to standing mode, the auxiliary motor 35 can be switched off as soon as an output signal due to the aligned position between field

SP synchronous window or opening and synchronous signal scanning position present. If this method were used directly, however, the reproduced still image would deviate by exactly half a field, as shown in FIG. 5 can be seen in FIG. 5 shows that the movie is now

is then stopped when the sync signal sampling position 32 coincides with the sync signal mark. At this point in time, the raster size for the Standing mode reduced to half its size during playback mode d. H. the sawtooth-shaped

th vertical scanning amplitude is reduced by half. This means that the standing grid is in the middle of the Playback operating grid is arranged, as can be seen from the cross-shaded and surrounded by a dashed rectangle box so that

Therefore, the scan extends over half of two adjacent fields the reproduced field is deflected by the length of half a field

2a. First measure in the event of inaccurate alignment of a stationary film half-image in relation to the grid position.

A first measure to rule out inaccurate alignment can be that the position of the grid on the light point tube shifted by exactly half a field length in the vertical scanning direction can be. This can easily be done by applying a direct current or a direct voltage of the required Amplitude as a direct current signal to the vertical deflection coil or the deflection electrode of the Light point tube happen. One can also get a direct current through a dedicated one for shifting Let the designated auxiliary deflection yoke flow. In this way, by decreasing the vertical grid amplitude to half the value given during playback operation and by moving the Grid position by half a field length - at the same time as switching to standing mode - one static representation of a precisely aligned field can be achieved.

2 B. Second measure in the event of inaccurate alignment of a stationary film half-image in relation to the grid position.

This second measure consists in providing an additional synchronizing signal sampling device which corresponds to position 47 in FIG. In other words, a scanning device is provided for the re-enactment of a stationary film frame, with which a synchronous signal scanning mark located at 47 is to be detected, which is a distance of half a field length or any multiple thereof from the position of the scanning mark 32 for the Sync signal is arranged in playback mode. According to the sync signal pickup device provided at 32, a light source 48, an optical fiber 49, an optical tube 50 and a photoelectric converter 51 are e.g. B. a phototransistor for the arranged at 47 additional scanning device is provided. The output signal emitted by the scanning device can be coupled to the switchover to the standing mode: cin, so that it is only switched on during the standing mode and switched off during the playback mode. The auxiliary motor 35 can by this output signa! be switched off. As a result, even if the vertical raster amplitude is reduced to half, if the film is stopped by the locking device corresponding to position 47 when a synchronous signal marking is detected, the field and the raster corresponding to the cross shading 34 according to FIG. 7 can be aligned. In this way, a steady reproduction of a precisely aligned field can be achieved. In playback mode, the sync signal is derived from the sync signal marker in position 32. In this case too, the two light sources 28 and 48 can be replaced by a single common light source, e.g. B. the light source 28. In other words, the light coming from a common light source can be guided through the respective optical fibers 29 and 49 to the locking positions 32 and 47.

2c. Third measure in the event of inaccurate alignment of a stationary film half-image with respect to the _{raster position 6j}

In this third measure, which is a modification of the above-described second measure, the synchronizing signal scanning device for playback operation, as well as the light source 28 assigned to it, the optical fiber 29, the optical tube 30 and the photoelectric converter 31 can be dispensed with the scanning device provided in position 47 serves only to generate the field adjustment signal at the time of standing operation and to generate the vertical sync signal in playback mode. In this case, however, the output pulse sampled as a vertical synchronizing signal is delayed by a period corresponding to half the field length, e.g. B. '/ eox' / j second in the case of a film speed of 60 fields per second, and the delayed signal is used as a synchronous signal to initiate the raster scan. Since the film speed is constant in playback mode, the signal delayed by this delay time corresponds to a synchronous signal derived in position 32, which is half a field length from the sampling position of the non-delayed signal, so that an aligned image can be reproduced in playback mode.

With regard to the field adjustment at the point of switching from playback mode to It should also be noted that the field alignment can also be set when the Standing operation of a certain field, a stab operation of the next following field or one at a time or several fields later followed by the subsequent field. Especially when standing, when the Auxiliary motor 35 is switched off by the output signal originating from the synchronizing signal marking State is maintained by temporarily switching off the output signal using a manually operated switch, the motor 35 is switched on again to initiate the film transport. Consequently the output signal disappears from the synchronizing signal marking. By pressing the switch again, as soon as this condition sets in, the film is stopped again when the output signal from the Synchronsignalmarkicrung for the next field appears, so that a standing display of the next Field is possible. If the switch is left in the switched-off state for a long time, the film can be transported over more than one field.

As already described, according to the invention, an aligned field can always be automatically achieved at the point in time of the standing display. so that the conventional cumbersome manual operation is eliminated; this is particularly advantageous if standing pictures are to be reproduced very often. With the mechanism according to the invention it is also possible to reproduce successive fields as still images, so that it is particularly advantageous when it is to be used as a search system for checking recordings image by image.

Although the above description is based on an EV R device, the same can be true Principles are applied to other devices for recording and reproducing fields, but which are similar to the EVR device for reproducing moving and still images.

3. Automation of standing mode and field alignment.

The previous description is a Automatic field alignment can be achieved if the user of the playback device is entitled to a still image showing desired moving field from a

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Program selects. For teaching purposes in particular, however, it is advantageous if not only movable ones Fields, but also fields to be reproduced as stationary pictures accordingly in the program content Can be used and when the playback of moving pictures automatically to standing playback can be switched as soon as the field of a stationary image reaches the scanning position.

To such an automatic switching and halftone alignment to achieve, are usually in advance in the appropriate places on the recorded film special control signals z. B. Automatic shutdown recorded so that when such a signal is sampled the operating status of the player switches automatically. Fig. 8 shows a recording film with Automatic shutdown signals. In this film, the automatic shutdown signal consists of alternating black and and white areas in a constant sequence recorded on the synchronous signal track. the In contrast to the white area, the black area does not allow light to pass through, so that from the synchronous signal detector an output signal of a certain frequency can be determined. Since the film speed is constant, is ensures that an output signal is obtained at a certain fixed frequency. This alternating signal is assigned to an appropriate section in front of the image to be reproduced as a still image Automatic stop signal field recorded. If this is on the section of normal movable The alternating signal section following the field is controlled by the synchronizing signal detector reached, this emits a signal of a certain frequency, so that due to the Operation switching mechanism of the player is operated. However, this requires a frequency discriminator, which complicates the setup of the facility.

In the following, a device is described with which an automatic shutdown signal can be made usable in a very simple manner in the automatic sound and field alignment mechanism using two such synchronous signal detection devices. In the film, as shown in Fig. 9, additional sync marks 3 'are boldly provided between the adjacent ordinary field sync marks 3. In other words, there is a series of synchronsignalmurkicrungen arranged, the distance from each other is exactly half the length of the field. These markings are used instead of the alternating signals according to FIG. 8 as an automatic shutdown signal.

Two synchronous signal detectors are used to detect this signal series, which are spaced apart by a mid-to-center distance corresponding to half a field length or any multiple thereof are arranged from one another. With this arrangement, a automatic shutdown mechanism when operated by these two detectors simultaneously Output signals are issued.

The pattern of automatic shutdown signals according to FIG. 9 can be recorded and determined much more simply and easily than the alternating signal pattern according to FIG. 8 Numerous effects can be achieved by using the automatic shutdown signal. In the former case it is e.g. B. necessary to record sync signals having the same shape as the ordinary sync markings on the middle between adjacent marks, and according to the invention it is not necessary to provide alternating signal patterns separately. No frequency discriminator is needed for scanning, but only a coincidence circuit with two inputs.

4. Automatic standing mode and field alignment without changing the grid size.

Fig. 10 shows one of the films in which fields for automatic standing mode are recorded in the In contrast to the ordinary movable half-di- • orers twice as long as the usual fields in the vertical scanning direction, as well as a mistake for recording an image in this auto standing playback film. This type of field will used to move the still picture with the scanning raster in normal playback mode Reproduce images. When playing back moving pictures, there is a need for Jump scanning the size of the scanning raster twice as large as the field size on the film in Vertical scanning direction. Accordingly, for the exact reproduction of a stationary field without Changing the scanning raster size the stationary field must have the same size as the scanning raster. For this reason, the field must be twice the length for exclusive use in standing display of the moving ordinary field.

F i g. 11 shows a film in which the field for the automatic standing mode is the same size as the raster and the field for the moving picture. One of the reasons why the size of the field for the automatic standing mode is not increased to twice the size of the field for the moving image, nor is the method of contracting the scanning grid size to half the size in the 3S stitching mode is that the contraction of the scanning grid size results in focal points in the phosphor screen of the light point scanning tube in the area of the contracted grid. In other words, the brightness in the contracted screen portion is likely to be lower than that in the rest of the phosphor screen due to the deterioration of the screen at this point. If this is the case, the brightness is no longer the same at the time the moving images are played back. This is also the case when a moving picture is displayed as a still picture. In this case, however, the duration of the standing operation is usually relatively short. On the other hand, in the case of the automatic still mode, the still image field on ^{SO becomes βη} 8 ^ βΐ «η for a relatively long time. in order to be explained and examined in detail, so that the probability of burning points is much greater and much more urgent countermeasures 8 ^β ! ^Γ0 '· ^β "have to be. A second reason is then as" SS a field which as a stand-where to be played back on a higher Auflösevermogen to be granted. When a still image, it often more on details than the mobile As a result, the same grid size is used for the reproduction of still images as for the continuous reproduction of moving images, so that an impairment of the resolution due to a contraction of the grid size is avoided.

The film of Fig. 11 is synchronized with a sync signal mark. «Markings for the automatic field alignment in In the case of a reproduction of moving fields provided as still pictures recorded on the synchronous signal track at positions which are of the

<f

Center line of the scanning raster perpendicular / ur vertical scanning direction are separated by a distance of one-half the field length or any Corresponds to multiples of this. These sync markers can also be used for automatic field alignment can be used in automatic standing mode. For this purpose, the sync markers as automatic standby field sync signals on the sync signal track of the film be provided in such places that the described scanning position for the alignment of the automatic The still image field and the scanning raster correspond. While the positions of the sync markers from the center line of the assigned automatic still image field by any Multiples / are removed (wooei / the distance from the front end of a moving field to the front

end of the next adjacent moving field), these sync markers belong to either row a or row b , as in Pig. 11 is shown. One of these rows is used selectively depending on the position of the sync markers with respect to the sync sampling position. This also means that the position of the detector can be determined in such a way that it corresponds to either row;) or row b.

By providing synchronic signal markers therefore, there is an automatic field alignment within the fields for automatic standing operation possible by means of a common detector, which unc at the same time serves the fields for standing operation, which is very advantageous for the reproduction as a standing picture.

For this (1 sheet of drawings

Claims (6)

Patent claims: K Image reproducing device for reproducing the half or partial images recorded in strips of successive fields on a tape-shaped recording medium such as a film (5) by scanning the individual fields in raster areas with the aid of a cathode ray tube under the control of synchronous signal markings attached to the film, which are read out by a synchronous signal reading device can be read out at a location fixed with respect to the raster areas along the film runway , with the sync signals read out in motion picture mode with a motion picture raster, the length of which in the film direction is twice the field length in this direction, serving as vertical sync signals, while in still picture mode a still picture raster of one field length is used , which lies in the middle of the moving picture grid, characterized in that the read-out point (47) from the nearest edge of the moving picture grid (33) is the distance / plus ch has half a field length. where / is the distance from an edge of a field to the same edge of the field following on the film (5). that in motion picture reproduction the signal read out by the synchronous signal readout device (48-51) serves as the vertical sync signal initiating the raster scan only after a delay time, which is equal to the lead time of the film (5) over a distance ' Ii , and that when switching over from motion picture reproduction on still image reproduction the signal read out by the synchronous signal readout device is applied without delay as a stop signal to a tape drive device, for example an auxiliary drive (35-43) for aligning the still image grid (34) with the field to be displayed as a still image. 2. Device according to claim 1, characterized in that that for the still picture reproduction, the drive device for the tape-shaped recording medium can be switched to an auxiliary drive for the advance of the tape-shaped recording medium. 3. Device according to claim 2, characterized in that a first scanning device is provided for detecting synchronous signal markings in motion picture playback, and a second scanning device for scanning synchronous signals, which is arranged at a distance 1/2 from the first device. 4. Device according to claim 3, characterized in that the auxiliary drive upon detection of a Synchronous signal marking for a moving picture by one by the second scanning device generated signal can be stopped. 5. Device according to claim 3, characterized in that the tape-shaped recording medium comprises a Stehbeltrieb Halbbild which is twice as long as the field of the motion picture in the direction of tape travel, as well as synchronization marks on a synchronization track at a distance of 1/2 from the center of the respective Still image operation fields are provided that the tape drive device can be switched to the auxiliary drive when a synchronous pattern is detected by both synchronous signal marking scanning devices and that the auxiliary drive can then be shut off when a synchronous signal marking is detected by the second scanning device. 6. Device according to claim 5, characterized in that between two adjacent iSynchronsignalmarkierungen for motion picture playback a further sync mark before Still image field is provided.