JPH0412677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention of this application relates to a recording device and a recording method for image signals, particularly a recording device and a recording method suitable for recording still images, and also relates to a recording device and a recording method suitable for recording still images. An object of the present invention is to produce a record carrier that can reproduce still images with good image quality and that can easily search for a desired screen.

Regarding the prior art Recently, attempts have been made to record and play back still images using image signal recording and playback devices that use magnetic tape (hereinafter referred to as video tape recorders). In addition to the method of taking the created photograph with a video tape recorder, it is also possible to take the photograph directly with a video tape recorder without using film. The invention of this application belongs to the latter category.

Record still images with existing video tape recorders
If you want to play it back, the following methods can be used:

() Recording is done by regular continuous shooting, and when playing back, the tape is stopped and viewed as a still image.

() Record the same signal for several frames using frame memory, etc., and then stop the tape during playback and view it as a still image. Or, repeatedly watch the part where the same signal is recorded.

() Stop the tape and record one frame, and also stop the tape when playing back. In the case of a two-head system, the same operation is performed using a head with a step of one track pitch.

Among these methods, () is not strictly a still image recording method, but is the simplest method. However, as shown in Figure 2, the tape T running in the direction of the white arrow
The recording head scans in the X direction in the figure when the tape is running, but the trajectory of this head (solid line) and the trajectory of the head when the tape is stopped (broken line) are 1 at the end of the recording track.
Since the head is shifted by the amount of the track, the output of the head becomes uneven when it is reproduced, and unless a special reproduction device that can displace the head using an electromechanical transducer or the like is used, deterioration in image quality is inevitable.
The same applies to (). In contrast, ()
Although this method does not have the disadvantages of methods () and (), it is difficult to search for a desired screen during playback because only one frame can be recorded. In other words, when the tape is run at normal playback speed, the display time of one screen in the NTSC format is only about 1/30 second, so unless you use a playback device that is capable of slow motion or single-frame forwarding, you will not be able to get the desired result. It is difficult to locate the screen.

Purpose of the invention of this application Therefore, the first invention of this application is a device for recording an image signal by winding a tape diagonally around a cylinder and scanning the tape with a rotating recording head. An object of the present invention is to provide a recording device capable of reproducing still images of good image quality even with a normal reproducing device having no functions.

The second invention is a method of recording an image signal by running a tape by winding it diagonally around a cylinder and scanning the tape with a rotating pre-recording head, in which an ordinary playback device having no special functions is used. It is also possible to play still images with good image quality,
Another object of the present invention is to provide a recording method that allows a desired screen to be easily searched during playback.

Structure of the invention of this application A first invention of this application is an apparatus for winding a tape obliquely around a cylinder and scanning the tape with a rotating head provided on the cylinder to record an image signal. a displacement means for displacing the tape in a direction transverse to the scanning direction; a pattern signal generation means for supplying a pattern signal to the displacement means for effectively matching the track pattern formed by the rotation head; a displacement means for displacing the rotary head in a direction transverse to its scanning direction; For example, the electrical/mechanical elements 17, 1 of FIG.
The image signal recording apparatus is characterized by comprising a circuit for applying a sawtooth voltage to the recording head 7' to apply a displacing force to the recording head.

A second invention is a method for recording image signals by winding a tape diagonally around a cylinder and scanning the tape with a rotary head provided on the cylinder, in which the tape is run and the same image signal is recorded in a plurality of frames. (In the specific example described later, the image signal is recorded in the frame memory 21 in FIG.
and record this. ), the track pattern formed by the rotating head effectively matches the track pattern formed by the rotating head when the tape is at rest and the rotating head is not displaced in the direction of its axis of rotation. The image signal recording method is characterized in that the rotary head is displaced in a direction transverse to its scanning direction.

In the above, the citation of the specific examples described later does not limit the scope of the invention of this application in any way, and the invention of this application can be modified as appropriate within the scope of the claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A tape running mechanism, an image signal recording apparatus embodying the first invention of this application, and an image signal recording method embodying the second invention of this application will be described in detail below with reference to the drawings.

About the record carrier traveling mechanism (Figure 1) Figure 1 shows a known tape traveling mechanism, in which the magnetic tape T is wound diagonally about 180 degrees around an upper rotary cylinder 1 and a lower fixed cylinder 2, and a capstan (not shown) is wound around the magnetic tape T. One or more rotary recording heads 3 fixed to the upper rotary cylinder 1 scan the magnetic tape T diagonally to perform recording. Therefore tape T
It is well known that the upper recording track is formed obliquely to the traveling direction of the tape T, as shown in FIGS. 2 and 3. In FIG. 1, 4 and 5 indicate vertical pins and inclined pins on the inlet side, respectively, and 6 and 7 indicate inclined pins and vertical pins on the outlet side, respectively.

Regarding the image signal recording device embodying the first invention of this application (FIGS. 3 to 5) FIG. 3 shows an example of a recording track pattern recorded by the recording device according to the invention of this application. There is. In the first and second inventions of this application, the recording head scans diagonally with respect to the tape T running in the direction of the white arrow in the figure, and a displacing force is applied to the recording head in a direction transverse to the scanning direction. . Therefore, when compared with the trajectory (broken line) when the above-mentioned displacement force is not applied to the recording head while the tape is running, the scanning locus (solid line) of the recording head changes at a rate of 1 track pitch t per 1 track length 1 in the figure. Since it moves in the Y direction, the track pattern when recording by running the tape is effectively the same as the track pattern when recording one track at a time by stopping the tape without applying any displacement force to the head. The means for applying a displacement force to the recording head is to support the recording head by an electro-mechanical transducer (for example, an electro-mechanical transducer bimorph element made of a piezoelectric crystal plate), and to apply a displacing force to the electro-mechanical transducer as shown in FIG. It is possible to apply a periodically repeated sawtooth voltage. Note that the manner in which the electromechanical transducer is displaced by the applied voltage and the manner in which the recording head is supported by the element are well known in tracking devices and the like, so detailed explanations will be omitted.

FIG. 4 shows the main parts of an image signal recording device embodying the invention of this application, in which 10 is a clock oscillator, 11 is a counter, 12 is a head switching pulse generation source, 13 is a DA converter, and 14 is a In the switching circuit, 15 and 15' are low frequency devices, 16 and 16' are amplifiers, and 17 and 17' are electromechanical conversion elements. This example is a two-head system, with two heads 3 and 3' each supported by an electromechanical transducer.
This is a device that switches and records. When recording still images, switch SW1 is switched to S contact,
A counter 11 counts clock pulses from a clock oscillator 10. Note that the counting operation of the counter 11 is set by inputting a head switching pulse to the RS terminal. The count output of the counter 11 is converted into a step wave by the DA converter 13, and the output is converted into a step wave by the switching circuit 14.
The signals are switched by a head switching pulse at , converted into a sawtooth wave by low frequency converters 15 and 15', and applied to electromechanical conversion elements 17 and 17' via amplifiers 16 and 16', respectively. As a result, electricity
The recording heads 3, 3' supported by the mechanical transducers 17, 17', respectively, receive a displacement force in a direction transverse to the scanning direction, so that their scanning loci are effectively made parallel to the scanning locus when they are at rest. .

The tape recorded by the above method is
It does not have a head displacement mechanism using mechanical conversion elements, etc.
A case will be described in which playback is performed using the most common video tape recorder, which does not have slow motion or frame-by-frame forwarding functions, but is capable of playing back when the tape is stopped. In the second invention of this application,
As shown in FIG. 3, the same screen A is repeatedly recorded in one cut, and the next screen B is recorded in the subsequent cut.
Therefore, when a tape having the recording track pattern shown in FIG. 3 is played back at normal tape speed,
The trajectory of the head will look like the broken line in Figure 3, so
The head output decreases in the latter half of the track, and there is more noise at the bottom of the screen, but this does not affect search.
Since the same screen can be viewed for a fraction of a second to several seconds, a desired screen can be easily found. For example, if 15 frames are recorded using the NTSC method, the screen will be switched approximately once every 1/2 second. When the desired screen appears, stop the tape and enter still image playback mode. At this time, as described above, the trajectory of the head effectively matches the recording track, the output of the head becomes constant, and good image quality can be obtained over the entire screen.

Regarding a method of recording an image signal embodying the second invention of this application (FIG. 6) Next, a method of continuously recording a plurality of frames of the same screen will be described. In the second invention of this application, when continuously recording a plurality of frames of the same screen, the output signal of a normal video camera may be recorded as is. However, this method cannot be called still image recording in the strict sense; for example, NTSC format
If you record 15 frames, it will record for 1/2 second,
If the screen changes during that time, the screen you see during playback will be different. However, one record is 1/5 to 1/2
If it is about seconds, there is no practical problem in most cases.

However, in cases where the subject changes at high speed, still image recording is required in a strict sense. To do this, it is sufficient to record using a frame memory. As shown in FIG. 6, the output of the imaging device 20 is transferred directly or via the frame memory 21 to the recording heads 3, 3' by the changeover switches SW2, SW3.
is supplied to When recording a still image, these switches are switched to the S side, and the output of the imaging device 20 is stored in the frame memory 21 and recorded by the post-recording heads 3, 3'. When shooting video, switch the switch to the M side and record directly. As the frame memory 21, a charge coupled device or a video disk may be used. Note that when the imaging device 20 is composed of a charge-coupled device, its transfer section can be used as a memory. As an alternative, it is also possible to use a signal obtained by reproducing, by an auxiliary head, a track that is one track ahead of the track to be recorded by the recording head. In any of the embodiments described above, a displacement force is applied to the recording heads 3, 3' in a direction transverse to the scanning direction so that when the tape is running, the scanning locus is the same as when the tape is at rest.

Effects of the Invention of this Application The first invention of this application is based on the above-described structure and operation, and provides a tape stop when the track pattern formed by the rotating head during tape running is not displaced in the direction transverse to the scanning direction. Since recording is performed by applying a displacement force to the rotary head in a direction transverse to its scanning direction so that the track pattern is effectively the same as that of the actual recording, it is possible to obtain good image quality even with an ordinary playback device without special functions. Still images can be played back.

In addition to the effects of the first invention, the second invention can realize a recording method that allows a desired screen to be easily searched during playback.

[Brief explanation of drawings]

FIG. 1 is a perspective view of main parts of a known tape running mechanism, FIG. 2 is an explanatory diagram showing a track pattern recorded by a conventional device, and FIG. 3 is a diagram showing a track pattern recorded by an image signal recording device of the invention of this application. FIG. 4 is an explanatory diagram showing the track pattern of this application.
FIG. 5 is a waveform diagram showing the voltage applied to the electromechanical conversion element in the device of FIG. 4, and FIG. 6 is a block diagram of an image signal recording device embodying the invention of FIG. 1 is a block diagram showing an apparatus for recording a plurality of consecutive frames of a screen; FIG. In the figure, 3 and 3' are rotary recording heads, 10 is a clock oscillator, 11 is a counter, 13 is a DA converter,
15, 15' are low frequency devices, 17, 17' are electric/
A mechanical transducer, 20 an imaging device, 21 a frame memory, and T a magnetic tape.

Claims (1)

[Scope of Claims] 1. A device for recording an image signal by winding a tape diagonally around a cylinder and scanning the tape with a rotating head provided on the cylinder, comprising: rotating the rotating head in a direction transverse to the scanning direction; a displacement means for displacing the tape; and a track pattern formed by the rotary head while the tape is running to be a track pattern formed by the rotary head when the tape is stopped and the displacement means is not operating. An image signal recording apparatus comprising: pattern signal generation means for supplying a pattern signal for effective matching to the displacement means. 2. The first aspect of claim 1, wherein the displacement means includes an electromechanical transducer that supports the rotary head, and the pattern signal is a signal that periodically has a level that changes over time. The image signal recording device described in Section 1. 3. A method of winding a tape diagonally around a cylinder and scanning the tape with a rotating head provided on the cylinder to record an image signal, in which the tape is run and the image signal of the same screen is transmitted over multiple screens. When recording continuously, the track pattern formed by the rotary head is the same as the track pattern formed by the rotary head when the tape is stopped and the rotary head is not displaced in the direction of its rotation axis. A method for recording image signals, characterized in that the rotary head is displaced in a direction transverse to its scanning direction so as to achieve effective coincidence. 4. The method for recording an image signal according to claim 3, wherein the image signal is stored in a memory that stores image signals for one screen, and image signals for the same screen are continuously obtained from the memory. .