JPS6034304B2 - Video special effect signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a video special effect signal generating device employed in a video image transmitting device used in a television broadcasting station, and particularly relates to a video special effect signal generating device having a circular shape (including an elliptical shape).

) relates to a wipe key signal generation device; An example of a special effect on a television screen is a so-called wipe or montage, in which a part of one image is embedded with another image.

In order to obtain such an effect, a key signal for selectively selecting two video signals is generated. A fader operating device for controlling the key signal to enlarge or decrease the size of the iron inset area of another image, that is, the wipe pattern area, and a positioner operating device for controlling the key signal to move the center of the wipe pattern are provided. There is. Here, the most common video special effect signal generating device will be explained with reference to FIG.

In FIG. 1, 2 is a horizontal fundamental wave generator, and 4 is a vertical fundamental wave generator. Normally, parabolic waves, mirror-tooth waves, triangular waves, etc. with a horizontal period and a vertical period are generated, respectively. In the explanation of the parabolic wave necessary for generating the key signal for the circular wipe, which is the object of the present invention (see Fig. 2b, for convenience of explanation, the horizontal period day and the vertical period V are expressed the same in Fig. 2). ) is generated. Each of the fundamental wave generators 2 and 4 is usually constructed from a simple integrating circuit, and since it is a common technique, a detailed explanation will be omitted.

Parabolic wave signals with horizontal and vertical periods respectively generated by the fundamental wave generators 2 and 4 are added in a synthesis circuit 5 to generate a superimposed parabolic wave as shown in FIG. 3a.

This superimposed parabolic wave signal is sliced at a slice level Ls by a slicing circuit 6 to generate a circular wipe key signal as shown in FIG. 3b. This key signal is applied to the video switching circuit 7, where two types of video signals V^,
The VB input is selected by the above key signal, and the output signal is V. is derived. When this world power signal Vo is displayed as an image on the television screen, an image B corresponding to the video signal VB is embedded in a circular shape into an image A corresponding to the video signal V^, as shown in FIG. Become something. Here, the fader operating device 10 in FIG. 1 changes the slice level Ls, and as a result, the size of the circle in FIG. 4 is zero (that is, the entire image is A).

) to the maximum state (that is, all images are Bo). In the above explanation, each fundamental wave generator 2
, 4 generate a parabolic wave as shown in Fig. 2b, which has a symmetrical waveform with respect to the center of the period of the horizontal drive pulse and vertical drive pulse as shown in Fig. 2a, and A wipe pattern located in the center of the television screen was obtained as shown.

On the other hand, the horizontal drive pulse and the vertical drive pulse are advanced or delayed in time by pulse phase adjustment circuits 1 and 3, respectively, as shown in FIG. When the fundamental wave generators 2 and 4 are driven, the center of the wipe pattern can be moved to any position on the screen above, below, left or right.

Figures 2c and d show drive pulses and parabolic waves that are delayed tH (for horizontal waveforms) and tv (for vertical waveforms) of the input driving pulses, and as a result, the center position of the wipe pattern on the TV screen is as shown in Figure 5. Move as shown. Note that in the phase adjustment circuits 1 and 3, the driving pulses may be simply delayed (
However, if the wipe pattern is increased using the fader controller 10, a portion of the parabolic wave as shown by the dotted line in FIG. 2d remains. This is undesirable because an unnecessary wipe pattern appears in another part of the screen, and usually waveform processing (twin prohibition processing) is used to remove part of the parabolic wave as described above so that it does not remain.

) is being carried out. Also, the positioner operating device 8 in Fig. 1
, 9 control the movement of the center position of the wipe pattern by generating a control signal for adjusting the amount of phase shift of the phase adjustment circuits 1 and 3.

However, the above-mentioned video special effect signal generation system has the following drawbacks.

That is, firstly, when the center of the wipe pattern is at the center of the screen, there is a complete cutoff from image A to image B, that is, the boundary line of the circle that is the area of image B in FIG. It expands to the circle F, and the entire surface is image B.
However, even if the pattern center position is moved using the positioner operating devices 8 and 9, the maximum radius R remains unchanged, and the farther the center of the circle is from the center of the screen, the more part of image A remains, and the entire area becomes part of image B. It is not possible to do so.

This is explained by the positioner operating device 8 as shown in FIG. 2d.
, 9, the cause is simply a movement of the phase of the parabolic wave, so it is considered unavoidable. In FIG. 2, due to the above-mentioned twin prohibition process, tH, tv
Since the parabolic wave component is removed during the period, depending on the position and size of the circle, it may not be the desired circle as shown by the dotted line in Figure 6, but may be a pattern that does not resemble a circle, as shown by the solid line. Put it away. Note that both the circular wipe pattern and the elliptical wipe pattern use parabolic waves, and the amplitude ratio of the horizontal parabolic wave and vertical parabolic wave determines whether the pattern will be circular or elliptical. Also suitable for both cases.

Now, as mentioned above, in order to be able to completely cut out the pattern even when the center of the pattern is moved, both the horizontal and vertical fundamental waves must have one horizontal wave no matter where the apex of the parabolic wave is, as shown in Figure 7. (or vertical) period, it is necessary to generate a continuous parabolic wave.

The present invention has been made to eliminate the above-mentioned drawbacks, and it is possible to move the position of a circular or oval wipe pattern stably and reliably, and it is also possible to move from one image to another regardless of where the center of the wipe pattern is on the screen. An object of the present invention is to provide a video special effect signal generating device that can completely cut out images.

That is, in the present invention, a parabolic wave whose phase and level are fixed and a separately generated sawtooth wave are mixed without changing the phase of the drive pulse input of the fundamental wave generator, and by changing this mixing ratio, the parabolic wave is generated. In other words, the phase of the parabolic wave is controlled, and continuous parabolic waves (see FIG. 7) are generated within each period in both the horizontal and vertical systems without performing twin prohibition processing.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 8 and 9. FIG. 8 shows a desirable waveform when the center of the circular wipe pattern is moved, that is, the apex of the parabolic wave in each of the horizontal and vertical fundamental waves is moved.

However, for convenience of explanation, the center of the screen where the wipe pattern related to the parabolic wave is obtained is shown as ○, and the left and right (or top and bottom) of the screen are shown as -1 and 11. Here, the parabolic wave when the center of the circular wipe is at the center of the screen is indicated by A, and its amplitude is set to 1. On the other hand, the parabolic wave when the wipe center goes to the horizontal scan start edge or vertical scan start edge of the screen, that is, the left edge or top edge, is shown as B, and its amplitude is 4.
It is. Similarly, the parabolic wave when the wipe center is at the right or bottom edge of the screen is indicated by C, and its amplitude is 4. Next, consider the case where the wipe center is at an arbitrary point a.

If the parabolic wave D at this time is expressed mathematically on the x and y coordinates shown in Figure 8, y=-(x-a)2
...{1).

Of course, when a=0, parabolic wave A, and when a=-1, parabolic wave B
, a=+1, which corresponds to parabolic wave C. The previous formula {1 Peng, if expanded, y; 1 x 20 x - a2
...(2}, and the above equation (2) can be expressed using the equation (y^=-x2) representing parabolic wave A, y=y^+back x-a2...{31, In short, for the parabolic wave A used in the prior art, that is, the waveform shown in Fig. 2b,
...{4' is added.

Here, the {4} formula is the sum of the negative equation of x and a constant term a2, and if expressed in a waveform, it is sufficient to superimpose the sawtooth wave and the DC component on the parabolic wave A. Furthermore, a2, which is a direct current component, changes depending on the control amount of the positioner, but this can be solved in terms of circuit technology by fixing the peak of the parabolic wave at a constant level.

The linear equation of x, that is, the sawtooth wave component, can be changed by the positioner control amount, that is, the corollary a of x, from a negative cointooth wave signal through zero to a positive sawtooth wave signal, and then added to the parabolic wave A. .

The maximum amplitude of the mirror tooth wave is x=1 and x=- when a=1
Since it is sufficient to take the difference between the values of the previous expression '4' in 1, it becomes 4, which is four times the parabolic wave A.

FIG. 9 shows an example of a circuit configuration for actually performing the above operation. In FIG. 9, 20 is a generator for a parabolic wave A having its apex at the center of the horizontal period, and may be the same as 2 in FIG. 1 described above. Reference numeral 21 designates a mirror-tooth wave generator whose output is applied to a transistor 22 constituting a polarity inverting circuit, and a sawtooth wave having opposite polarities and equal amplitude b is obtained at the collector and emitter of this transistor 22, respectively.

This chain tooth wave signal has an amplitude 4b that is four times the parabolic wave output amplitude b of the parabolic wave generator 20, and the variable resistor 23
The sawtooth wave whose amplitude and polarity are adjusted by the mixer 24
By mixing it with the parabolic wave A in addition to the parabolic wave A, it is possible to obtain the parabolic wave D whose apex is located at an arbitrary location and which is continuous over one period as shown in FIG. Here, the variable resistor 23 may be the positioner adjuster itself, or may be a circuit system of the same mechanism controlled by the positioner adjuster.

For convenience of explanation, taking the variable resistor 23 as an example, when the movable contact of the variable resistor 23 is at the upper end in FIG. 9, the parabolic wave C in FIG. When the contact point is at the lower end in FIG. 9, the parabolic wave B in FIG. 8 appears at the output of the mixer 24, and the movable contact point is located in the middle part of the sliding range, and the two polar waveforms exactly cancel each other out. 8, the output of the mixer 24 is of course the parabolic wave A in FIG. The output waveform of the mixer 24 is determined by the capacitor 25 and diode 26 that constitute the peak clamp circuit.
As shown in FIG. 8, the apex of the parabolic device is adjusted to a constant level, and the signal is further guided to a mixer 28 via a buffer amplifier 27. On the other hand, the vertically periodic parabolic wave signal produced in the same manner as above is led to the mixer 28, where the horizontal and vertical parabolic waves are mixed, and then the slice circuit (corresponding to FIG. 16).

). This peak clamping operation automatically corrects the constant term a2 in the previous equation (2).

In other words, simply mixing a sawtooth wave of variable amplitude with the parabolic wave A using the variable resistor 23 does not result in the DC level of the peak portion of the resulting waveform being in the equation {4'; however, this is corrected. be. Next, another embodiment of the present invention will be described with reference to FIGS. 10 and 11.

The previous formula (can be transformed into a quadratic formula).

y ni {1 x 2-Koichi 1} 10 {2(a+1)x-(a
2-1)} ...'5} The first term on the right side of the above formula {5- is
This is parabolic wave B in FIG. 8, and the second term consists of a linear expression of x and a constant term.The coefficient of x changes from 14 to 0 while changing from a=1 to -1.

In other words, the waveform of the previous equation '5' can be created by adding the parabolic wave B whose apex is at the end in FIG. 8 and the sawtooth wave whose amplitude changes. The waveforms in FIGS. 11a and 11b show this relationship. The waveform of a is the first term on the right side of the previous equation (5), that is, the parabolic wave B in Figure 8, and the waveform of b is the sawtooth waveform that is the linear expression of x in the second term on the right side of the previous equation shows a wave E,
The amplitude may be changed from 0 to the maximum amplitude as a changes from -1 to 11, and this maximum amplitude is twice that of the parabolic wave B from the previous equation {5-. Next, FIG. 10 shows an example of a circuit configuration for performing the above operation. In Figure 10, 31 is a parabolic wave B whose apex is at the edge of the horizontal period.
32 is a sawtooth wave generator shown in FIG. 11b. Reference numeral 33 denotes an amplitude controller for the sawtooth wave signal, in which the amplitude-controlled mirror-tooth wave signal is mixed with the parabolic wave B at a mixing register 24. The subsequent circuit configuration is the same as that shown in FIG. 9, and will therefore be omitted. The circuit shown in Fig. 10 differs from the circuit shown in Fig. 9 in that the sawtooth wave signal only needs to have one polarity, and has the advantage that the amplitude of the sawtooth wave can be controlled with a simple circuit configuration. . Note that the DC component a2
9 and 10 both show a peak clamp method using a simple diode and capacitor as a correction method.
Any other method may be used as long as the peak level of the parabolic wave is fixed.

Furthermore, in both the circuits shown in Figs. 9 and 10, the desired waveform can be obtained only by a combination of the parabolic wave and the mirror-toothed wave, and furthermore, the apex movement of the desired parabolic wave is simply a function of the amplitude and polarity of the mirror-toothed wave. It has the advantage that it can be realized by a reliable and easy configuration in terms of circuit design, since it only needs to be controlled.

Note that the above-mentioned features are not limited to the circuits shown in FIGS. 9 and 10, but in short, the parabolic wave signal is continuous within each cycle and has a constant amplitude, and at least the amplitude and polarity are controlled. Other circuit configurations can also be obtained by using a combination with a sawtooth signal.

As described above, according to the present invention, a parabolic wave whose phase and level are fixed is mixed with a separately generated key-tooth wave, and by changing this mixing ratio, the peak of the parabolic wave,
In other words, the phase of the parabolic wave is controlled, and continuous parabolic waves are generated in each period in the horizontal and vertical systems without performing twin prohibition processing, and after the parabolic waves in the horizontal period and the vertical period are combined, A key signal for wiping is generated by slicing.

Therefore, it is possible to provide a video special effect signal generating device that can completely cut out one image into another image no matter where on the screen the center position of the circular or elliptical wipe pattern is moved.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing a subsidiary video special effect signal generating device, FIGS. 2 a to d and FIGS. 3 a and b are timing waveform diagrams shown to explain the operation of FIG. Figures 6 to 6 are diagrams shown to explain wipe patterns on the television screen in different operating states of Figure 1, Figure 7 is a timing waveform diagram showing parabolic waves to be generated by the device of the present invention, and Figure 8 9 is a diagram showing the time and amplitude of the parabolic waves to be generated by the apparatus of the present invention in relation to the scale of the television screen, and FIG. 9 is an embodiment of the video special effect signal generating apparatus according to the present invention. A configuration explanatory diagram showing
FIG. 10 is a configuration explanatory diagram showing another embodiment of the present invention;
1A and 1B are waveform diagrams shown to explain the operation of FIG. 10. 20... Parabolic wave generator, 21...
Mirror tooth wave generator, 23... Variable resistor, 24, 28
...Mixer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] 1. Generating a wipe key signal for selectively controlling two types of video signals to generate a circular or oval wipe pattern on the television screen, and controlling the movement of the center position of the wipe pattern on the television screen. In a video special effect signal generation device equipped with a positioner operation means for generating a parabolic wave signal that is symmetrical or asymmetrical with respect to the center of the television horizontal period and a parabolic wave signal that is symmetrical or asymmetrical with respect to the center of the television vertical period. parabolic wave generating means for generating a signal, sawtooth wave generating means for generating a sawtooth wave signal of a television horizontal period and a sawtooth wave signal of a television vertical period, and an amplitude of a sawtooth wave signal output by the means. means for arbitrarily controlling the polarity by the positioner operating means; and means for synthesizing the sawtooth wave signal controlled by this means and the parabolic wave signal and slicing the synthesized signal to obtain a wipe key signal. A video special effect signal generating device comprising: