JPS6034305B2 - Video special effects signal generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a generator for video special effect signals used as control signals when combining a plurality of television video signals in a specific pattern.

A video special effect signal generator such as the one shown in FIG. 1 is known.

That is, 1 and 2 are generators for horizontal component fundamental waves and vertical component fundamental waves, respectively, and their output waveforms are normally as shown in Fig. 2a,
These are sawtooth waves, triangular waves, and parabolic waves as shown in b and c, or harmonics of integral multiples (usually 3 to 12 times) of these waves. The type, polarity and phase of these waveforms, as well as their combinations, are arbitrarily selected depending on the special effect pattern finally obtained. The outputs of horizontal and vertical components from the fundamental wave generators 1 and 2 are sent to the slicing circuits 7 and 2 via mixing circuits 3 and 4 and control circuits 5 and 6, respectively.
Added to 8.

The characteristics of the slice circuits 7 and 8 are generally as shown in FIG. 3a, so that the input waveform as shown in FIG. 3b becomes the sliced output waveform as shown in FIG. 3c. By increasing the amplitude of the input waveform or making the sloping part of the slice characteristic steeper, the output waveform can be made close to the rectangular shape shown in figure d, and by using these properly, the final It is also possible to softly blur the boundaries of the screen (Figure c) or sharpen them (Figure d). Further, the outputs of such slice circuits 7 and 8 are delivered to a terminal 10 as an effect control output signal via a combination selection circuit 9, and a gain control/mixing circuit 12 is controlled by this signal.

That is, in this gain control/mixing circuit 12, two video input signals A and B are converted into a fourth video signal by the effect control output signal.
It is controlled as shown in the figure. In the above, the mixing circuits 3 and 4 are used to change the type of effect screen that can be obtained. For example, after closing the switch 11 and combining the vertical fundamental wave with the horizontal fundamental wave, the slicing circuits 7 and 4
By holding and slicing it, it is possible to create an effect screen such as a diagonal wipe, a diamond wipe, or a circular wipe.

The control circuits 5 and 6 are composed of gain control, polarity inversion, DC addition circuits, etc., and as mentioned above, by changing the gain, the boundaries of the effect screen can be changed from soft to sharp, and horizontal and vertical gain can be changed. You can change the aspect ratio of the effect screen by changing them separately. This gain control may be performed at the output section of each of the fundamental wave generators 1 and 2. Furthermore, it is possible to determine the changing direction of the effect screen by reversing the polarity, and to change the slice position and move the border of the effect screen by controlling the added DC value by operating the feeder on the control desk. FIG. 5 shows, as a specific example of the above, the case where the horizontal and vertical fundamental waves are both mirror-toothed waves, the switch 11 is turned on, and the combination selection circuit 9 selects only the output of one of the slice circuits 7. The figure a shows the input waveform of the slice circuit 7, the figure b shows the input waveform of the slice circuit 7,
c is the waveform of the effect control output signal derived from the terminal 10'.

Also, d and e in the same figure are screens when the output of the gain control/mixing circuit 12 controlled by the effect control output signal is viewed on an image receiving monitor. However, the conventional video special effect signal generator as described above has the following drawbacks. In other words, the position of the boundary line on the effect screen is determined by the relative relationship between the slice level (points P, S, and T in Figure 3) and the waveform to be sliced, so both of them are stable and can be controlled in the desired control form. However, since an IJ actance component such as a coupling capacitor is usually included before the slice circuit, balance remains during gain control, fader operation, etc., making the screen difficult to see. Therefore, if the circuit is designed using a DC coupling method as much as possible in order to eliminate this, humidity drift is likely to occur.

Additionally, clamping with a horizontal pulse just before the slice circuit can improve the situation, but even if you clamp the horizontal component waveform, if you clamp the vertical component waveform as it is, you will end up removing the necessary waveform component, which is inconvenient. be. In addition, if the boundary of the effect screen is to be changed continuously from a soft shape to a sharp shape, the input waveform amplitude of the slice circuit can be increased by performing gain control before the slice circuit as described above. The waveform U is changed to V as shown in
Considering the case of amplification to a level of , the center position of the slice moves from P to Q, which is undesirable because the center of the boundary of the effect screen moves as a result.

In this case, ideally the waveform U and waveform V as shown in figure b
′, but in order to achieve this, it is necessary to change the superimposed DC level or slice level in a constant relationship at the same time as changing the gain, and it is necessary to develop a circuit that can stably perform this type of operation. This is extremely difficult to achieve. Furthermore, in the specific example shown in Fig. 5, if the amplitudes of both the horizontal and vertical fundamental waves are changed in opposite directions, the horizontal fundamental wave and the vertical fundamental wave are changed as shown in Fig. 10 a, b, and c. A so-called rotating wipe is obtained in which the boundary I rotates in the direction of arrow A in relation to the waves and the effect screen, but in this case it is extremely difficult to fix the rotation center Ro for the same reason as in the above case. It is. Above all, since analog integrating circuits are generally used as fundamental wave generators, errors when compared with ideal waveforms, such as poor linearity and symmetry, and insufficient stability, It becomes even more difficult to fix Ro.

Therefore, in order to eliminate the above-mentioned drawbacks, this invention
A digital fundamental wave oscillator is used to control the fundamental wave generator so that a portion of its output waveform corresponding to part or all of the planking period reaches a specific reference level. The slicing point is stabilized by synthesizing the bound fundamental wave or a plurality of similarly bound fundamental waves, and performing pulse clamping on this composite signal in front of the slicing circuit and within the period of the above reference level. At the same time, by making the center values of the clamp level and the slice level the same, the center point of the slice does not move even if the amplitude of the fundamental wave and their composite wave is changed, and the reference level is changed. It is an object of the present invention to provide an extremely good video special effect signal generator that can move the boundary of the effect screen independently of the change in amplitude. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

However, in FIG. 6, components that are the same as those shown in FIG. In order to obtain stability, a digital system is used, as will be described later.

Further, 23 and 24 are clamp circuits for the above-mentioned pulse clamp inserted before the slice circuits 7 and 8. Also 2
5 is a reference pulse generation circuit for determining the position and width of the period from the horizontal planking pulse to the reference level, but this reference pulse may be the horizontal planking pulse or the horizontal drive pulse as it is. However, depending on some circuit design reason, the width may be made narrower than that. Further, reference numeral 26 denotes a clamp pulse generation circuit for the pulse clamp, but this may normally be the same as the reference pulse or a pulse having a width narrower than that of the reference pulse. By the way, the digital fundamental wave generation circuits 21 and 22 described above will be described later, but before that, the shape of the generated waveform, which is one of the features of the present invention, will be explained.

That is, as shown in FIGS. 7b and 7c, the reference level EH,
This is the waveform with E and v inserted. In other words, in FIG. 7c, pulse notches and protrusions appear in the fundamental wave output of the vertical component, and the level of that portion is Ev. Also the 7th
In the example of FIG. b, the horizontal component wave has no cut or protrusion, but the reference level EH is also inserted. Here, whether the reference levels EH and Ev are the same or different is essentially irrelevant. It goes without saying that the reference levels EH and Ev are inserted during a period corresponding to the blanking period of the reference pulse shown in FIG. Figure 7d shows the sixth
In the figure, when the switch 11 is turned on, the waveform is a composite waveform of two fundamental waves, corresponding to the specific example of FIG. 5.

This is because the clamp pulse from the clamp pulse generation circuit 26 is applied to the slice circuit 7 after clamping the reference pulse portion of the clamp level Lc in the clamp circuit 23, and is sliced due to the characteristic of having a slice width W centered at the slice level Ls. Indicates the case where Therefore, in this case, the output of the slice circuit 7 is as shown in FIG.
As shown in FIG. 5g, a waveform similar to that shown in FIGS. 5b and 5c is obtained. Note that the reference level is omitted in FIGS. 7f and 7g. Next, another feature of the present invention, in which the clamp level Lc and the slice center level Ls are made the same, will be explained with reference to FIG.

That is, FIG. 8a shows a case where Lc and Ls are different, and in this case, if the waveform U to be sliced is amplified to form a waveform V, the center point P to be sliced because Lc and Ls are different. moves to Q, the waveform obtained as an output also changes from X to Y, and the boundary changes from a soft shape to a sharp shape on the effect screen, and at the same time, the position also moves, which is inconvenient. However, as shown in Figure 8b, if Lc = Ls, which is a feature of this invention, even if the input waveform is amplified from U to V', the point P will not move, and the output waveform will also have the relationship between X and Y. Since the center does not move, only the width of the border on the effect screen changes from soft to sharp. Further, in this invention, the clamp circuits 23, 2
Due to the function of 4, even if various waveform controls are performed by the control circuit 5 as in the past, the vertical component is not impaired, and a stable effect control signal waveform is obtained regardless of the DC drift before the clamp circuit. be able to. The above is mainly the signal path 3 → 5 → 23 → 7 of the above example in Figure 6.
As explained above, the lower signal path 4→6→24→8
The same applies to

Next, another feature of the present invention, which is the addition of a reference level to the digital fundamental wave generation circuits 21 and 23, will be explained. That is, FIG. 9 shows one representative example of the configuration of the digital fundamental wave generation circuits 21 and 22. Normally, to digitally generate this type of fundamental wave as shown in Figure 2, a predetermined waveform relationship is stored in a non-volatile memory and read out during horizontal or vertical periods, or horizontally or vertically. A predetermined waveform relationship may be created by performing calculations each time at vertical timing. In FIG. 9, 92 is a non-volatile memory or an arithmetic circuit, and 91 is a control circuit for the output address of the non-volatile memory or a control section of the arithmetic circuit. Here, the output of the non-volatile memory or arithmetic circuit 92 is usually an 8-12 bit binary code signal, and this can be added to the D/A converter 93 and converted to an analog signal to produce the desired fundamental wave output. . A clock pulse 94 applied to the address control circuit (or arithmetic control unit) 91 is used to determine the address of the memory 92 and control the arithmetic speed, and a horizontal or vertical drive signal 95 is used to control the address and repeat the arithmetic operation. Used for synchronization. The characteristic of this case is that the planking pulse 9
8 or within the period of the above-mentioned reference pulse created by the driving pulse, a logic address corresponding to a specific level of the fundamental wave is given to the memory, or an output corresponding to the specific level of the fundamental wave can be taken out within the same period. This is to have an arithmetic circuit perform an operation. As a result, the output of the D/A converter 93 has E as shown in FIGS. 7b and 7c.
A waveform having reference levels H and Ev can now be extracted.

One of the controls corresponding to the specific level described above is performed by a fader signal 96' applied to the address control circuit (or arithmetic control section) 91. That is, a fader signal 96 from a fader adjuster (not shown) on the console is sent to move the border line on the effect screen, and this signal causes the EH, Ev
If we change the level of P in Figure 8b as a result,
You can move the points to achieve the objective. Similarly, a positioner adjuster 97 from a positioner adjuster (not shown) on the operation desk controls the timing of address specification and the timing of the calculation start point in the case of a normal effect waveform, thereby controlling the timing of the address specification and the timing of the calculation start point on the screen of the effect waveform. This is to move the position vertically and horizontally, but in order to determine the center of rotation for special effect waveforms such as rotation wipe, in place of the fader signal 96 in these effect waveform modes, E
Used for controlling H/Ev. In other words, if this is explained using the example of Fig. 7, the effect screen obtained by using b and c in the figure as fundamental waves will be as shown in Fig. 5 d and e, as described above. When the amplitude is increased and the amplitude of c is decreased, a rotational wimping effect is obtained in which the boundary line Lc rotates in the direction of arrow A, as shown in FIG. Here, waveforms g and h in Figure 10 (b in Figure 7)
If the relationship between EH/Ev in (corresponding to , c) and the Ro point is made to correspond as shown by the broken line in the figure, even if the amplitude of the g and h waveforms is changed, the center of rotation will always remain at the Ro point without moving. Become. Therefore, we want R to be the center of rotation on the screen. The address control circuit (or arithmetic control unit) 91 in FIG. 9 performs control to read out the level of the horizontal fundamental wave g at the timing th on the horizontal time axis of the point, that is, the level of the RH point, as the reference level EH of the reference pulse period. If this is done, a waveform g in FIG. 10 will be obtained, and a waveform h will also be obtained in the same way. Then, if the waveform obtained by combining g and h obtained in this way is clamped as described above and sliced at the same level, the point where RH and Rv coincide on the screen, that is, the Ro point, will be the amplitude of the g and h waveforms. It remains immovable no matter what.

In other words, even if the amplitude of the g and h waveforms in Fig. 10 are changed to produce a waveform as shown by the dashed line in the figure, the center of the slice level and the clamp level are the same as described above, so the Ro point will not be reached. Corresponding parts are fixed and do not change. In addition, in the above case, when a so-called circular wipe is performed by using parabolic waveforms for the horizontal and vertical fundamental waves as the fundamental wave, it is necessary to move the wipe boundary line using the fader on the console and to change the circular wipe screen obtained thereby. The relationship with the diameter becomes linear, and the non-linearity caused by the conventional method is improved.

In other words, in the conventional method, a waveform that is a mixture of horizontal and vertical parabolic waves as shown in Fig. 11 is used at the slice level L.
A circular wipe with radius R is obtained by slicing with s, and the radius R is changed by controlling the DC superimposed value of Ls or the mixed waveform by fader operation, but the DC signal given from the fader and the radius R Since the fundamental wave is a parabolic waveform, the relationship between the two is a quadratic function, so even if you move the fader at a constant speed, when the radius R is large, the change will be slow, and conversely, when the radius R is small, the change will be rapid. As a result, linearity is lost. However, according to the present invention, the drawbacks of the above-mentioned conventional system can be essentially eliminated, and will be explained below with reference to FIGS. 12 to 14. That is, FIG. 12 shows a parabolic wave fundamental wave including a reference pulse obtained by the present invention, which is the same both horizontally and vertically except for the difference in time ratio and the accompanying vertical waveform notch. As described above, the amplitude of the reference pulse in this fundamental waveform is read out at the level at point P on the fundamental wave after time t has elapsed from the start point of the waveform. The waveform actually applied to the slice circuit is a composite of horizontal and vertical parabolic fundamental waves, as shown in Figure 13.
As described above, one feature of the present invention is to clamp the reference pulse synthesis portion and then slice it at the slice level Ls. However, for the explanation of Figures 12 to 14, the aspect ratio of the screen is set to 1 for ease of understanding.
:1, so in the case of actual aspect ratios, the values shown in these figures will partially differ, but this is not related to the essence of the present invention. By the way, in this case, the radius of the circular wipe on the final screen is R = 2, as shown in Figure 14.
It becomes r.

Here, r is given as r=tf-t from FIG. 12, and tf is the readout time t by the fader.
shows the range of change. Therefore, the relationship between the information t given by the fader and the radius R of the circular wipe obtained is a linear function, that is, a linear relationship, and when the circle on the screen is made smaller by fader operation as in the conventional method, the rate of change is It is easier to operate since it does not suddenly increase in size. Looking at this from a different perspective, the conventional method is equivalent to changing L by operating the fader in Fig. 12, and the relationship between r and L, which is proportional to the radius of the circle, is a quadratic function. According to this invention, since r itself is changed by the control signal from the fader, it is natural that the relationship is linear. Note that the waveforms in the figures used in each of the above explanations are expressed with the horizontal and vertical time ratios exaggerated for ease of understanding, and may differ slightly from the actual waveforms.

In addition, in each of the above explanations, horizontal planking (a certain part is a horizontal and vertical composite planking waveform) does not cause any trouble to the operation. Therefore, as explained above, according to the present invention, a digital fundamental wave generator is used to generate the fundamental wave so that a portion corresponding to a part or all of the blanking period of the output waveform becomes a specific reference level. Controlling the generator, synthesizing the fundamental wave obtained in this way or a plurality of fundamental waves obtained in the same way,
Pulse clamping is performed on this composite signal before the slicing circuit and within the period of the above reference level to stabilize the slicing point, and at the same time, by making the central value of the clamp level and the slicing level the same, the fundamental wave and the center point of the slice does not move even if the amplitude of the synthesized wave is changed, and by changing the reference level, the boundary of the effect screen can be moved regardless of the change in the amplitude. This makes it possible to provide an extremely good video special effect signal generator.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a conventional video special effect signal generator.
FIG. 2 is a waveform diagram showing various fundamental waves in FIG. 1, FIG. 3 is a waveform diagram explaining slice characteristics in FIG. 1,
Fig. 4 is a curve diagram showing the control characteristics of the two video inputs in Fig. 1, Fig. 5 is a waveform diagram and screen state diagram of each part showing a specific example of the effect screen obtained by Fig. FIG. 7 is a block diagram of the main parts showing one embodiment of the video special effect signal generator according to the present invention, and FIG. 7 is a waveform diagram of each part according to FIG.
The figure is a waveform diagram showing the effect when the slice level and clamp level in Figure 6 are made the same in correspondence with the conventional system. Figure 9 is a configuration diagram of the digital fundamental wave generation circuit in Figure 6. The figure is a diagram explaining the state of the effect screen obtained by FIG. 6, FIG. 11 is a diagram explaining the circular wipe effect according to the conventional method, and FIGS. 12 to 14 are diagrams explaining the circular wipe effect according to FIG. 6. It is a figure explaining an effect. 21...Horizontal fundamental wave generation circuit, 22...
・Vertical fundamental wave generation circuit, 3, 4... Mixing circuit, 5, 6... Control circuit, 23, 24... Crumb circuit, 7, 8... Slice circuit, 9... Combination selection circuit, 12...Gain control/mixing circuit, 25.
...Reference pulse generation circuit, 26 ... Clamp pulse generation circuit, 91 ... Address control circuit (or arithmetic control section), 92 ... Nonvolatile memory (or arithmetic circuit) , 93...D/A converter. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14

Claims (1)

[Claims] 1. A first means for digitally generating a desired fundamental wave by a digital waveform storage circuit or a digital arithmetic circuit, and a portion corresponding to part or all of the blanking period of the output fundamental wave by this first means. a second means for controlling the fundamental wave output by the first means to a specific level; a third means for converting the fundamental wave output by the first means into an analog fundamental wave; a fourth means for synthesizing the analog fundamental waves of and clamping them to the specific level; and a fifth means for slicing the clamped output signal from the fourth means so that the center value of the slice level and the clamp level are the same level. 1. A video special effect signal generator comprising the following means.