JPS6034309B2 - Video special effect signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video special effect signal generation device employed in a video transmission device used in a television broadcasting station, and more particularly to a rotation wipe key signal generation device.

There are many types of key signals for wiping a TV screen, but most of them simply move the wipe boundary line in parallel or in the enlarged direction. Typical examples include circular wipe, diamond wipe, and vertical wipe. , horizontal wipe, corner wipe, etc.

In addition to these wipes, there is a method of rotating the border line around a certain point, but it has not been widely used because it has the disadvantage that the center part cannot be fixed sufficiently on the screen. A circuit system for obtaining rotational wipe of a slave will be described below with reference to FIG.

1 and 2 are horizontal and vertical fundamental wave generation circuits, in which sawtooth waves, triangular waves, etc. having respective periods are generated.

The following explanation will focus on an example of a sawtooth wave to facilitate understanding of the content, and cases of other waveforms such as a triangular wave will be explained as necessary, but essentially they are the same. 3 and 4 are bell regulators, which are expressed here as variable resistors for convenience, but of course other circuit systems may be used.

5 is a mixing circuit that mixes and adds horizontal and vertical fundamental waves that have been adjusted by a bell, and slices the world's power at a specific level in a slicing circuit 6 to create a key signal for wiping.

The key signals created in step 6 are two television video signals V^, V
It is added to the selection gate circuit 8 of B, where the screen is switched according to the key signal, and a signal Vo is created in which one image is embedded in the other image according to a predetermined wipe pattern.

Here, it is the level adjusters 3 and 4 that cause the wipe boundary line on the screen to rotate. This relationship will be explained using the waveform in FIG. 2 and the effect on the screen in FIG. 3. In order to make the following explanation easy and accurate, the horizontal and vertical fundamental waves are expressed as WH and Wv, their mixed fundamental wave as WHv, and the gate key signal obtained by slicing it as Wx. did. In Figure 2, the horizontal fundamental wave WH and the vertical fundamental wave W
By mixing v with the same amplitude, a mixed fundamental wave WHv shown by a solid line in the waveform diagram a is obtained. Here, the horizontal and vertical time ratios in Figure 2 are exaggerated compared to reality. When this mixed fundamental wave W is sliced at the slice level Ls, the waveform shown in FIG. 2b is obtained as the key signal WK.

This b waveform controls the switching circuit 8 and outputs V. When the signal obtained as is expressed on the screen as shown in Figure 3, A
, B The two television screens are separated by a boundary line indicated by a solid line. Next, when the level adjusters 3 and 4 increase or decrease the horizontal fundamental wave WH and the vertical fundamental wave Wv in opposite directions, for example, the horizontal fundamental wave WH increases and the vertical fundamental wave Wv
, the mixed fundamental wave W shown by the dotted line in waveform diagram a
Hv' is obtained, and in the same way, the key signal WK' is shown in the waveform diagram c.
obtained as follows.

If we look at the phase of the rising part of the key signal WK' that creates the wipe boundary line, we can see that at the top of the screen, that is, to the left of the waveform diagram, the key signal WK' is to the left of WK, and at the bottom of the screen, the key signal WK' is To the right of WK, press P in the center of the screen.
It doesn't move at points. Therefore, the boundary line in FIG. 3 rotates around point P as a dotted line. This is the basic principle of rotary wipe. However, the rotation center point P cannot always be stably obtained.

This will be explained with reference to FIGS. 4, 5, and 6.

FIG. 4 shows the mixed fundamental wave WHv of FIG. 2 in another representation, that is, in a state where the waveform is monitored at a vertical period on an oscilloscope.

First, the wipe boundary of the screen by the key signal obtained by slicing the waveform a of FIG. 4 at the slice level Ls is the same as that of FIG. 3, and is represented by a in FIG. 5.

Next, by slicing at the slice level L3 using a waveform b obtained by increasing the horizontal fundamental wave WH and subtracting the vertical fundamental wave Wv, the boundary line b in FIG. 5 is obtained. With the same machine, boundary line c in FIG. 5 is obtained corresponding to the waveform in FIG. 4 c. What needs to be noted here is the mixed fundamental wave WHv and the slice level Ls.
In the above explanation, it is assumed that the slice level Ls is always at the center of the amplitude of the mixed fundamental wave WHv, as shown in FIG. However, it is generally difficult to maintain such a state all the time. Because, ○}
The level adjusters 3 and 4 not only change the horizontal and vertical fundamental waves WH and Wv, which are AC components, but also change the DC component.

In order to avoid this, a fundamental wave generation method can be considered in which the DC components of the horizontal fundamental wave WH and the vertical fundamental wave Wv are made zero, but since the DC components are zero, it is difficult to obtain long-term stability.

'3' Furthermore, the fundamental wave generating circuits 1 and 2 must be directly connected to the slice circuit 6, and stability is likely to be lacking in this respect as well. ■ Instead of using the above direct coupling method, use AC coupling,
A predetermined bias may be applied just before the slicing circuit 6, but if the rotation is controlled rapidly, a transient phenomenon will occur and it will take time to settle down.

For these reasons, it is difficult to maintain stable conditions on a daily basis, even immediately after carefully adjusting the circuit.

As a result, the slice level L for the mixed fundamental wave WHv
The mutual relationship of s varies, and for example, as shown in b and c of FIG. 4, the slice level changes to Ls'. In the example of Fig. 4, as the waveform changes from a to b to c, the relative relationship of the slice level to the mixed fundamental wave WHv becomes Ls', and as a result, the rotation boundary line moves as shown in Fig. 6. The rotation is performed independently of the point P at the center of the screen, and there is no point that is the center of rotation.

Although the case where both the horizontal fundamental wave WH and the vertical fundamental wave Wv are sawtooth waves has been described above, the same can be said about the case of other waveforms.

For example, if you want to obtain the wipe effect as shown in Figure 7, use the vertical fundamental wave Wv, which used a sawtooth wave in the explanation up to now.
A triangular wave can be used for this.

Figures 8, 9, and 1 represent the waveform changes and screen changes in this case in the same way as Figures 4, 5, and 6.
This is figure 0. In this case, the 9th change, which is originally a desirable change,
In order to obtain the rotational movement of the boundary line shown in the figure, unless the relationship between the mixed fundamental wave WHv and the slice level Ls in FIG. 8 is maintained accurately, the center of rotation will shift as shown in FIG. 10. In FIG. 8, the slice level Ls' is shown as an example in which it deviates above Ls, but if it deviates downward, it becomes as shown by the dotted line in FIG. Such defects occur regardless of the fundamental wave, and another example is the 11th wave.
As shown in the figure, the effect that the shaded area spreads in a fan shape around point P can be created by using triangular waves for both the horizontal fundamental wave WH and the vertical fundamental wave Wv, but the mutual relationship between the slice point and the mixed fundamental wave WHv is still If it is not fixed, the tip will become separated as shown in Figure 12. These things not only make it impossible to obtain the desired wipe screen, but also result in an unsightly wipe screen where the center of rotation is not determined. A complete conversion to screens will not be possible. As described above, it is not sufficient to obtain the rotation center P point approximately, but it must be obtained accurately and reliably, but this has been difficult with conventional devices for the reasons mentioned above.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and provides a video special effect signal generating device that makes it possible to realize a variety of tap functions by easily, reliably, and accurately fixing the center of rotation. It is.

An embodiment of the present invention will be described in detail below with reference to the drawings.

The video special effect signal generation device shown in FIG. 13 differs from the conventional video special effect signal generation device described above with reference to FIG. The same parts as those in FIG.

Now, the first difference between the device of the present invention and the conventional device is that
Rather than using the fundamental wave generated by the fundamental wave generation circuits 1 and 2 as is, a reference level is inserted into a predetermined section by the reference level insertion circuits 11 and 12, and then the level is adjusted and mixed.

The predetermined period referred to here is a period inserted in advance to clamp the fundamental wave or its mixture before slicing, and normally a pulse within the horizontal planking period is desirable.

Pulse a shown in FIG. 14a is a pulse for creating a predetermined section, and may be a horizontal planking pulse or a horizontal driving pulse.

Figures 14b and 14c show examples of inserting reference pulses when sawtooth waves are selected as the horizontal and vertical fundamental waves. In each waveform, reference levels LH and Lv are inserted during the period of pulse a. has been done.

Although any means may be used to insert such a bell into the original fundamental wave, the circuit shown in FIG. 15 can be used, for example. Here, the transistor TRI forms an emitter follower, and the original fundamental wave applied to the input appears at its emitter. On the other hand, the transistor TR3 generates a reference level, and a DC voltage determined by the ratio of the resistors R2 and R3 is applied to the base, and a DC voltage is applied from the low impedance emitter to the emitter of the transistor TR2.

This transistor TR2 forms a switching circuit,
When a positive pulse is applied to the base through the capacitor C, it is turned on for that period, and the collector is connected to the transistor T.
It becomes a constant level determined by the DC voltage supplied from R3 to the emitter. This level is inserted as a reference level and
During other periods, the transistor TR2 is connected through the resistor RI.
The original fundamental wave appears at the collector of . The pulse supplied via capacitor C here is, of course, the inverted polarity of the pulse shown in FIG. 14a. A transistor TR4 forming an output emitter follower is connected to the collector of the transistor TR2, and a signal is supplied to the next stage via the transistor TR4. Note that the reference level insertion circuit shown in FIG. 15 described above is an example, and the reference level that has a certain relationship with the original fundamental wave is inserted before performing processing such as level control on the original fundamental wave. Any means of insertion may be used.

As mentioned above, the fundamental waves WH, W with the reference level inserted
v is controlled and further mixed, but this is exactly the same as before.

Next, the second difference between the device of the present invention and the conventional device is that
When slicing the waveform-processed mixed fundamental wave WHv, this mixed fundamental wave WHv is pulse-clamped within the predetermined section by the clamp circuit 13, and the clamp level is kept at a constant value, and the constant value, that is, the clamp level. This means slicing at the same slicing level.

Figure 14 d shows the relationship between the mixed fundamental wave WHv and the slice level Ls. Of course, it is a mixture including the parts, but the reference level part is clamped as described above,
As a result of slicing at the same slice level Ls, a key signal WK is obtained as shown in FIG.

What is important here is the case where the horizontal fundamental wave WH and the vertical fundamental wave Wv are respectively increased or decreased, and the respective waveforms at that time, that is, WH, Wv, WHv, WK are shown by dotted lines in FIGS. 14b to 14d and f. When the increase or decrease is made in this way, as can be seen from the figure, the slice is sliced at the same slice level Ls as when no increase or decrease is made as shown by the solid line, and this slice level Ls
Since is always the same as the reference level section, no matter how the bell control or mixing is performed, whether the transmission path is direct connection, AC coupling, or even if there are DC fluctuations, Irrespective of this, since it is clamped before slicing, the waveform relationship shown in FIG. 14d is obtained. This relationship is equivalent to the relationship between the mixed fundamental waves WHv, WHv' and the slice level Ls shown in FIG. 2, and the relationship between the mixed fundamental wave W-v and the slice level Ls shown in FIG. The relationship between the mixed fundamental wave WHv and the varied slice level Ls' as shown in FIG. 1 does not essentially occur.

If the reference pulse is normally inserted within the horizontal retrace period, its presence will be ignored on the final television screen.

Further, when we examine the device of the present invention, we find the following interesting facts.

FIG. 16 represents each waveform shown in FIG. 14 in another way, and is convenient for understanding waveform processing by the apparatus of the present invention.

That is, in Fig. 16, the horizontal and vertical fundamental waves WH and Wv shown in Fig. 14b and c are displayed on the screen in the respective time directions in correspondence with the time axis on the TV screen. The relationship between the reference level on the fundamental wave and the rotation center of the wipe pattern created by the mixed fundamental wave in which each fundamental wave is mixed can be seen at a glance. In this figure, it goes without saying that there are exactly as many reference level cuts in the vertical fundamental wave Wv as there are scanning lines, but for convenience of display, they are expressed as a set. As can be seen from Figures 14b and 14c, the rotation center point P on the TV screen corresponds to the timing at which Pv coincides with the point PH where the original fundamental wave and the reference level intersect for each of the horizontal and vertical fundamental waves WH and Wv. is obtained as a point that does not move no matter how the levels of the fundamental waves WH and Wv are controlled. Therefore, according to the apparatus of the present invention, by determining the intersection points PH and Pv between each fundamental wave and the reference level, the rotation center point P of the wipe pattern can be easily determined.

As another example, what happens when the wipe pattern shown in FIG. 7 described above is obtained by employing the present invention will be described. That is, in order to obtain the wipe pattern shown in FIG. 17, the horizontal fundamental wave WH is a sawtooth wave and the vertical fundamental wave Wv is a triangular wave, as is the case with the prior art, but the reference level is set as shown in FIG. The horizontal fundamental wave WH is inserted at the lower end of the sawtooth wave, and the vertical fundamental wave Wv is also inserted at the same level as the tip of the triangular wave. As a result, the intersection points PH and Pv between each fundamental wave and the reference level are at the positions shown in the figure, and the rotation center point on the TV screen that corresponds to the timing when these intersection points PH and Pv coincide is fixed at the center of the left side of the screen. Since the wipe boundary changes at the center,
The phenomenon of change in the center of rotation as shown in FIG. 10 does not occur. Similarly, FIG. 18 shows an example in which a triangular wave is applied to the horizontal fundamental wave WH and a sawtooth wave is applied to the vertical fundamental wave Wv.

Furthermore, other waveforms, such as parabolic waves, may be used as the fundamental wave, and as an example, FIG. 19 shows an example in which a parabolic wave is used as the horizontal fundamental wave WH. At this time, the effect is that the parabolic wipe border, which has a fixed center at the bottom center of the screen, expands to the left and right.

Moreover, as shown in FIG. 20, if each fundamental wave WH and Wv are triangular waves and the reference level is set to the middle level of the waveforms,
The intersection point PM and Pv of each fundamental wave and the slice level are both 2
Each point is tied, and a rotation effect around four points P, .about.P4 on the television screen can be obtained.

As described above, according to the device of the present invention, a reference level is inserted into each predetermined section of the horizontal and vertical fundamental waves, the mixed fundamental wave is pulse-clamped within the predetermined section of the front muscle, and the slice level is the same as this clamp level. Since the slices are sliced with a , the center of rotation can be easily and reliably fixed, and various rotational effects can be created accurately.

Further, when performing waveform processing such as level control, the DC level may be ignored in the design, increasing the degree of freedom in design.

Furthermore, even when rapid waveform control is performed, the movement of the center of rotation is hardly visible because it is clamped by horizontal period pulses. As described above, the present invention can provide a video special effect signal generating device that can realize a variety of wipe functions by easily, reliably, and accurately fixing the center of rotation.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing a conventional video special effect signal generation device, FIGS. 2 a to c are waveform diagrams shown to explain the operation of FIG. 1, and FIG. Figures 4a to 4c are waveform diagrams in which the horizontal and vertical waveform ratios of the waveform of Figure 2a are different, and Figures 5 and 6 are waveform diagrams of the The figure is shown to explain the rotational change of the wipe boundary line when the slice level Ls of the waveform shown in the figure is constant and when it changes. Figures illustrating examples; Figures 8a to 8e are diagrams showing the waveform changes of the composite fundamental wave necessary to obtain the rotational changes of the wipe boundary line in Figure 7; Figures 9 and 10 are the waveforms in Figure 8; The first diagram is shown to explain the rotational change of the wipe boundary line when the slice level of is constant and when it changes.
1 and 12 are other examples of the wipe pattern on the TV screen obtained by the operation shown in FIG. 1, showing cases in which the center of rotation is constant and cases in which the center of rotation changes, and FIG. 13 is a diagram showing cases in which the center of rotation is changed. 14a to 14f are waveform diagrams shown to explain the operation of FIG. 13, and FIG. 15 is a reference level insertion diagram of FIG. 13. A circuit diagram showing an example of the circuit, FIG. 16 is a diagram shown to explain the relationship between the horizontal and vertical fundamental waves in FIG. 14 and the wipe pattern on the TV screen, and FIGS. 17 to 20 are respectively shown in FIG. 13. FIG. 6 is a diagram shown to explain the relationship between the horizontal and vertical fundamental waves and the wipe pattern on the television screen in another example of the operation of the device. 1, 2... Fundamental wave generation circuit, 3, 4...
・Level adjuster, 5...Mixing circuit, 6...
... Slice circuit, 11, 12 ... Reference level insertion circuit, 13 ... Clamp circuit. Figure 1 Figure 3 Figure 5 Figure 6 Figure 7 Figure 2 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 15 Figure 20 Figure 4 Figure 8 Figure 16 Figure 17 Figure 14 Figure 18 Figure 19

Claims (1)

[Claims] 1. In a video special effect signal generation device that generates a key signal for controlling the switching and selection of two types of video signals to generate a rotating wipe pattern on a television screen, horizontal and vertical signals with a predetermined section set to a reference level are used. fundamental wave generating means for respectively generating a horizontal fundamental wave signal and a vertical fundamental wave signal having a period of a control means; a mixing means for mixing the horizontal fundamental wave signal and the vertical fundamental wave signal whose amplitudes are controlled by the means to obtain a mixed fundamental wave signal; A video special effect signal generating device comprising key signal generating means for clamping at a predetermined clamp level only in a level setting section and then slicing at the same level as the clamp level to generate a rotation wipe key signal.