DE1086739B - Method and device for recording and reproducing images produced by television means - Google Patents

Description

GERMAN

Magnetically storing television image transmissions is known. To the belt speed and thus To reduce the consumption of magnetic tapes, it is also known to move the magnetic heads periodically. Furthermore, methods have become known in which the to be transmitted. Images divided into image parts be e.g. B. in that each line is assigned a track that is longitudinal or oblique to Direction of movement of the tape is recorded. You also have the television signals in several Tracks saved on one or more drums. In doing so, each track was just one Contains part of the image to be transmitted, assigned a pair of heads. About an inertial transition To receive the signals from track to track, an electronically controlled distributor was provided. These known methods and devices have in common that a larger number of magnetic heads is required, which have to be switched electrically, which in practice encounters great difficulties.

The main patent application relates to a method and a device for recording and reproducing of X-ray images with television means, those produced by an X-ray image television recording tube, time-divided X-ray image television impulses on the circumference of an image frequency revolving, magnetic, endless memory are recorded, so that each a complete X-ray image the size of the memory is omitted. The means described there are intended to prevent the The photon noise of the X-ray images was limited To improve the visibility of contrast and detail by making a limited number richer in information Images is saved without any appreciable delay for observation for any be available for a long time.

It is known to record image pulses on an endlessly revolving tape, and also in several adjacent tracks can be made. It is also already known the traces in adjacent Record turns. To with a time expansion or time lapse impulses of a television picture To be able to play back, the blanking gaps of the recorded signal from picture track to picture track have to be increased the same surface line of the magnetic drum storage. With a helical record the image impulses alone therefore cannot be expanded or compressed in time.

It is also known to use magnetic memories for time expansion or time lapse.

According to the present invention, the magnetic recording of television means reproduced X-ray images required setup procedures and equipment

for recording and playback

by means of television means

generated images

Addition to patent application Z 4773 VIIIc / 21 g
(Auslegesdmft 1 055 700)

Applicant:

Zeiss Ikon Aktiengesellschaft,
Stuttgart S, Dornhaldenstr. 5

Dr. Manfred Keller, Kiel-Wik,
has been named as the inventor

Device for partial playback of slow-motion or time-lapse recordings as well as individual recordings used from television broadcasts.

When using the magnetic image memory as a time stretcher (slow motion), the a television broadcast coming video-frequency television signals continuously to the scope of the Recorded in memory. However, the recorded television signals are sampled in slow motion, d. that is, each saved image is not just once, but; many times depending on what you want Time stretching, sampled. When using the magnetic image storage as time-lapse or as Individual image generators, on the other hand, are only the desired individual images from the incoming television signal sequence faded out and saved. The sampling of these temporally gathered single images takes place either with normal frame rate, or each individual image is scanned many times in a row, z. B. those that are not related to each other in terms of image content.

When storing image content that does not change continuously, the television signals applied next to each other in a ring on the circumference of the memory.

When using the memory to record continuously changing image content, like this z. B. is the case with slow motion recordings, the image signals are helical and, if the phases of movement change slowly, temporarily recorded in one another. The recording takes place as an intensity font.

009 570/17 +

3 4

If a head is assigned to each image track, it is displayed, that is, in the case of time-lapse recordings. Because in this

there is an extraordinarily great effort. Hence the case between the frames to be recorded in

if there is only one recording for all tracks - there is usually enough time, the

head and one or two playback heads are used, the image signals of the individual images when the recording

Moving along the axis of the drum storage unit, the drawing head is moved separately in a ring on the circumference

the can. of the memory. For storage

If the recording is carried out with the next image signal ringing side by side, the recording

head lying on the circumference of the accumulator beforehand by a full track width

Tracks, the magnetic head must shift during the time.

duration of the blanking intervals between the individual images. The playback head moves

dern, i.e. in a very short time (Vsoo second), from appropriately step-by-step from track to track, whereby

be transported from one lane to the other. The length of time for this movement depends on whether a

the recording can be achieved helically on the circumference hard or soft dissolve effect

of the memory, these difficulties should be avoided, larger or smaller than the storage time of the

went. Depending on how quickly the recording eye (about 0.1 second) is to be selected. It understands

opening head is moved along the storage drum, it goes without saying that this arrangement can also be used as a single

can already during the recording process by the imager, z. B. for test images can be used

Writing the traces of images into one another can result in a time lapse.

be made. In the case of a fast moving target, a television picture is displayed on the circumference of the drum where each image is to be recorded separately 20 with 625 lines according to the interlaced method, If the head has to be drawn for each revolution of the memory, then for the case that the line drum be shifted by a full track width. clock of the scanned signals with the line clock of the

The speed with which the playback head is to match the signals to be recorded, which is moved, is arbitrary and depends on the playback head to be offset by 312 or 313 lines with respect to the desired time expansion or time lapse in the case of the recording head. Dignity of playback. When the playback / playback head is quasi stationary, namely exactly the recording head head, the latter alternates between two tracks, if opposite, this would come to 312.5. Line so that a cross-faded image content to lie in the image direction, which would have the consequence that the lines of two temporally adjacent images are reproduced beginning of the scanned image compared to that of the. Since the frame rate with 25 frames shifts by half a line for every 30 lines to be recorded. Second during the recording process not as in the case of the displaced by half a line the arrangement of a cinematographically working slow motion increased playback head, on the other hand, the can shift, at least not when it comes to the image blanking gaps by half a line width. Since the storage is from a current program, blanking gaps can be re-entered into the scanned signal anyway, only the movement phases per V25 second are to be keyed in, this shifting and fixing. In the case of fast-moving processes, half a line is irrelevant. If the devices to be connected to the jump memory, which is unavoidable during playback, do not result in an adhesion of the images.
To achieve that one does not scan the two fields second second field then also repeatedly from head with regard to its position to the circumference of the Speitastet. In this way, the image scanners can assume the same height as the sequence of 25 images per second to 50 images per 45 drawing head.

Artificially double the second. Inevitably, an image the size of the storage device is required

in the event of a loss of resolution in the image, the following considerations serve: The? u

direction. planning drum diameter of the memory is

In order to determine the image content with regard to the temporal increase by the upper limit frequency to be scanned,

resolving power to the field frequency of 50 with a realizable gap width s = 3 μ des

To increase 50 frames per second, the following playback head, a peripheral speed

Process engineering are applied: On the Um- z / = 30m / sec, which at 25 U / sec = 1500 U / min a

At the beginning of the drum, as before, two drum diameters of 38 cm are obtained

Corresponding fields by means of a recording at a recordable limit wavelength λ = 50μ

head recorded. However, an amplitude response of the in

two playback heads, the voltage induced in their distance by 312 after the playback head

or 313 lines are offset from one another. Fig. 1, curve a.

These heads are now alternately conphas to In this graph, the abscissa is the frequency and the image phase is switched to 25 Hz. In this way the tension is plotted as an ordiante. This span can be for each field separately, as can easily be seen from the formula:
can be scanned in succession as often as desired. J_ ■

The switch to the following field is done E - kfe ^ -,

by reversing the polarity of the 25 Hz switching frequency in such a way, ^α

that this is expediently done automatically when. _jts . _ ν

^{the playback heads} by half a track width 65 ^{wonn a} ~~} T '^ -

have moved. It can be advantageous, the s means the gap width of the playback head,

Moment of polarity reversal conphas with the image phase λ the wavelength of the oscillation to be recorded

to be done. gen, ν is the peripheral speed of the upper drum

It is different when recording a single image area and α or ^ ₁ limit values of the wavelength or

follow procedure that does not have continuous content 70 of the frequency.

χ ν / vj Kj ι

The losses due to self-demagnetization of the carrier material and the influence of the gap function were taken into account. When using Ni-Zn ferrite, the head losses of up to 10 ⁷ Hz can be neglected. The widening of the gap resulting from porosity was disregarded. It was further assumed that the field strength at a point above the gap of the recording head is proportional to the input voltage. From the curve α it can be seen that the EMF drop at 5 MHz has the same level as at 1 kHz. However, frequencies lower than about 1 kHz do not necessarily have to be recorded with television signals, since this lower frequency range including the direct current component can be regained to the level of the line blanking intervals by automatic black control. As a comparison, curve b shows the idle EMF for a magnetic sound device. The calculation was based on a gap width j = 14μ, a belt speed ν = 72 cm / sec and a _{cutoff wavelength A 1} = 100 μ. After that, the level drops below that at 1 kHz from 20 kHz. Due to the low dynamics of the television images (1:10 to 1:15), a track width of 1 mm is sufficient. Since an average scene duration of 5 seconds can be expected, with 25 images per second and a track width of 1 mm a drum length of 125 mm results. As these general considerations show, usable drum dimensions are obtained.

An embodiment of the proposed device is explained with reference to FIG. It puts an embodiment, as it is as a time stretcher or time lapse or as a single image generator in television broadcasting Can be used.

The mechanical device of the arrangement consists of the storage drum 1, which is particularly careful must be balanced and stored. The drum shell is covered with a ferromagnetic film 2, which has a small band flow loss, d. H. has a small cutoff wavelength and coercive force. The magnetic head 3 is used for recording and the magnetic head 4 is used for reproducing. Thus the eddy currents and hysteresis losses in the core material of the heads remain small, are either finely laminated sheets (50 μ) or ferrites should be used. An extinguishing head 5 with an extinguishing generator is also to be provided. A synchronous motor 6 is used to drive the storage drum rotating at frame rate. The transport device 7 and 8 with the transport spindles 9 and 10 ensures the lateral displacement of the magnetic heads. A control unit 11 and 12 are provided for each recording and playback.

In order to record continuous image sequences, the recording head 3 is positioned above the transport spindle 9 moved continuously, whereby the speed can be regulated. The highest speed is so too choose that the head is offset by one track width per revolution of the drum. When recording single images the head stops while an image is being recorded and only afterwards will after the recording shifted by one track width. The mechanical means required for this are not shown. A similar device is provided for moving the playback head 4. To control the movements of the heads and the amplifiers are partly mechanical, partly Electrically operating operating devices for the recording 11 and playback device 12 are available.

The control of the motion sequences can be done manually or automatically, depending on the implementation of the Control devices and transport equipment.

The television signals are fed to the recording amplifier 13. To be as consistent as possible To obtain magnetization of the carrier 2, the high Frequencies increased and thus the frequency drop as a result of the head losses of the gap influence and to the

ίο Part also the influence of the self-demagnetization of the Bearer balanced. The output stage 15 contains a clamping circuit, which in a known manner Restores DC component in the image signal. The recordings of the television signals can likely take place without pre-magnetization. The distortion caused by the sharp curvature in the That occur around the zero point of the remanence curve are shifted to the area of the blanking pulses and are therefore meaningless. So that the blanking pulses are above the magnetization threshold (greater than about 60 Örsted), these must be re-keyed into the image signal, which is done via terminal 16 he follows.

Also a recording according to the HF pre-magnetization process, which has a better signal-to-noise ratio brings is conceivable. The decay strength of the field .111 of the trailing edge of the recording head must be however, be very small, which must be taken into account in the manufacture of the recording heads.

The recording amplifier is controlled from the operating device 11 via the line 17. Should one current image sequence are recorded, the preamplifier 18 is unlocked. When recording of a single image, on the other hand, the amplifier is only opened during the duration of an image. The there / .u required pulse has exactly the length of an image, and the phase position of this pulse is correct coincides with that of the image phase.

The playback amplifier 19 has the task of applying the voltage induced in the playback head to amplify the standardized output level. The input circle for elevation is useful as Form resonance circuit. A post-equalizer 20 is used to linearize the frequency response, the by the differentiating scanning process, by the gap influence and by those dependent on the frequency Self-demagnetization losses in the carrier is caused, as well as for delay equalization. By a clamp circuit in the output stage 21 becomes the direct current component as in the receiving side restored. To renew the output pulses, they are added via terminal 22. The playback amplifier is also controlled by the operating device 12 via the line 23. One Unlocking voltage releases the preamplifier stage 24, and the image signal reaches a fader stage 25. In this stage, the stored, temporally expanded or gathered image signal can be converted into the direct Transition line 26 are displayed.

The proposed procedures and the facilities required to carry them out are for the various fields of technology can be used, e.g. B. Radar technology, navigation, astronomy and microscopy.

Claims (10)

Patent claims: 1. Magnetic recording method and reproducing generated by television means Images, their temporally dismantled impulses recorded on the circumference of a magnetically writable memory rotating at frame rate are, according to patent application Z 4773 VIIIc / 21g, characterized by the use for the magnetic recording of x-ray images available as television images required facility for the partial playback of slow-motion or time-lapse recordings as well as individual recordings from television broadcasts. 2. The method according to claim 1, characterized in that in the storage of itself continuously changing picture contents the television signals helically on the circumference of the memory be applied. 3. The method according to claim 1, characterized in that not in the storage of itself continuously changing picture content the television signals side by side in a ring on the circumference of the memory can be applied. ao 4. Device for performing the method according to at least one of the preceding Claims, characterized in that the magnetic heads provided for recording and playback are arranged displaceably to the axis of the storage drum. 5. Device according to claim 4, characterized in that the magnetic heads step by step or can be moved continuously at a controllable speed. 6. Device according to claim 4 or 5, characterized in that the magnetic recording and playback devices on the circumference of the storage drum offset by an angular amount are arranged to one another, the 312 or 313 Lines of the image scan. 7. Device according to at least one of the preceding claims, characterized in that that two magnetic playback heads are provided, offset from one another by 312 or 313 lines, the konphas can be switched to the frame rate of 25 Hz. 8. Device according to claim 7, characterized in that the polarity reversal of the 25 Hz switching frequency takes place automatically at the point in time at which the playback heads have shifted by half a track width. 9. Device for storing individual images according to at least one of the preceding Claims, characterized in that special switching elements are provided from the incoming TV transmission, only the desired individual images get to the memory permit. 10. The method according to at least one of the preceding claims, characterized in, that the blanking pulses are keyed into the image signals to be recorded with such a size that these pulses form the non-linear part of the remanence curve during the magnetization process disqualify. Considered publications:
German patents No. 728 838, 856 075, 999; German patent application S 1258 VIII a / 21 ¹ made known on 15.2. 1951);
Umschau, 1953, no. 8, p. 247. 1 sheet of drawings