JPS6058630B2 - special effects waveform generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a special effects waveform generator for practical use in television special effects, and more particularly to a stripe wipe special effects waveform generator.

To generate a special effect waveform signal for a so-called stripe wipe in which the boundaries of the screen change sequentially over several lines as shown in Fig. 1 a, b, and c, the conventional method is shown in Fig. 2 a. It was obtained by superimposing the vertical periodic fundamental wave shown in FIG. 2 with the horizontal periodic fundamental wave shown in FIG. 2 and comparing it with the fader voltage in a comparison circuit.

In this method, as shown in FIG. 2, it is necessary to make the amplitude of the horizontal period smaller than the vertical period fundamental wave. Therefore, it becomes susceptible to the influence of mixed noise. For example, this is 8
It is easy to see that as the number of lines increases, the effect of noise increases. Furthermore, when obtaining a so-called soft edge waveform with blurred boundaries, it is not possible to uniformly blur all boundaries because a stepped fundamental wave is used. SUMMARY OF THE INVENTION It is an object of the present invention to provide a special effects waveform generator that generates special effects waveforms whose boundaries move over several lines without these problems except for the drawbacks of the prior art. In the special effect waveform generator of the present invention, the determination of stripe connections is performed digitally accurately and stably, and the comparison operation that creates changes due to the fader control voltage is always obtained by comparison with a signal with a large amplitude. Therefore, unlike in the past, when the number of lines is increased, the boundary will not become unstable due to noise.

Next, the present invention will be described in detail with reference to the drawings showing one embodiment of the present invention.

FIG. 3 shows an embodiment of the present invention. In the figure, there are a vertical periodic fundamental wave generation circuit 1 and a horizontal periodic fundamental wave generation circuit 2 for generating a fundamental wave according to a special effect. The outputs of the fundamental wave generation circuits 1 and 2 are sent to comparison circuits 3, 4 and 5, and compared with respective predetermined slice levels to form special effect waveforms. The special effect waveforms are combined by logic operation circuits 6 and 7 and output from an output terminal 8. In FIG. 3, the vertical periodic fundamental wave is sent to comparison circuits 3 and 5, and the horizontal periodic fundamental wave is sent to comparison circuit 4. On the other hand, a control voltage from a fader 9 that controls the movement of the special effect waveform is sent to a sampling hold circuit 10 and an analog-to-digital (A/D) conversion circuit 12.

A sampling pulse with a vertical period is supplied to the sample hold circuit 10 from a terminal 11. The sample hold circuit 10 compensates for delays caused by the A/D conversion circuit 12 and the like. A vertical periodic pulse is supplied to the A/D conversion circuit 12 from a terminal 13 . The A/D converter 12 converts the control voltage from the fader 9 into a multi-bit digital code. The fader data division control circuit 14 receives the digital code from the A/D conversion circuit 12 and the row number selection control signal from the terminal 20, and converts the digital to analog conversion circuit 15,
16 and 17. The operation of the fader data division control circuit 14 will be explained next. Now, for example, when performing the special effect shown in FIG. 1, it is necessary to move three lines of stripes with one movement of the fader 9. Therefore, the fader division control circuit 14 divides the output data of the A/D converter 12 into three stages, and sends output data that changes stepwise in three stages to the D/A converter 15. The D/A converter 15 converts it into an analog signal, and the mixing circuit 18 converts it into a sampling hole. It is mixed with the fader control voltage from the field circuit 10 to create a sawtooth wave with three cycles per period of operation of the fader 9 at the output of the mixing circuit 18. Mixing circuit 18
The output is a sawtooth pattern with a period corresponding to the number of stripes that divide the screen per one operation of the fader 9. Since waves are generated, the amplitude decreases as the number of lines increases. Therefore, the output of the mixing circuit 18 is amplified by the gain control circuit 19. Since the degree of amplification can be set constant depending on the number of rows, the row number selection control signal from the terminal 20 is also supplied to the gain control circuit 19. The output of the gain control circuit 19 is sent to the comparator circuit 4.
It becomes the slice level of the horizontally periodic fundamental wave.

Therefore, the output φ1 of the comparator circuit 4 has an effect waveform in which the operation of the screen rising from the left end is repeated three times for each operation of the fader 9. In the operation of the comparison circuits 3 and 4, even if the number of rows increases, the amplitude of the output of the gain control circuit 19 does not decrease, so that an accurate and stable effect waveform can be obtained. Further, the fader data division control circuit 14 outputs data indicating the slice level corresponding to the position on the screen of the stripe that divides the screen.
The signal is sent to A converters 16 and 17. D/JA converter 16,
The signals indicating the slice level converted into analog signals at 17 are supplied to comparators 3 and 5, respectively, to slice the vertical periodic fundamental wave. Therefore, the outputs φ2 and φ4 of the comparison circuits 3 and 5, respectively, become waveforms that divide the screen at predetermined height points on the screen. The data to the D/A converters 16 and 17 is predetermined in the form of a special effect, that is, a stripe wipe, and is controlled by the fader data division control circuit 14. FIG. 4 shows the comparison circuit 4,
Outputs φ1, φ2, φ4 of 3 and 5, output φ3 obtained by ANDing outputs φ1 and φ2 in logic operation circuit 6, and output φ5 obtained by ORing outputs φ and output φ4 in logic operation circuit 7. and are displayed in correspondence with the effects on the screen. Of course, if the outputs φ1, φ2, and φ4 of the comparison circuits 4, 3, and 5 are combined in other ways, even different effects can be obtained. It is clear that when the number of boundaries formed by stripes increases, the number of outputs from the fader division control circuit 14, D/A converters 16 and 17, and comparison circuits 3 and 5 should be increased accordingly. be.

In addition, in the description of the embodiment, a sawtooth wave is used as the horizontal periodic fundamental wave and the vertical periodic fundamental wave, and the horizontal periodic fundamental wave is sliced by the fader control voltage, but various other embodiments are possible. I can make it. For example, if a triangular wave is used for each fundamental wave, a stripe wipe that changes from two places at the same time can be created. Moreover, if a signal with an integral multiple of the fundamental frequency is used as the fundamental wave, even more special effects can be created. In other words,
Horizontal and vertical fundamental wave generating circuits generate fundamental waves of different shapes, fundamental waves of fundamental periods, harmonics, and waves of different polarities, and all these signals are passed through a switch to each comparison circuit 3, 4, and 5. The slice levels of the D/A converters 16 and 17 are controlled according to the special effect, the combination of outputs of each comparison circuit, the width of the staircase wave output from the D/A converter 15, etc. If the switching data of the switching device is stored in the memory included in the fader data division control circuit, it is possible to automatically create various stripe wipes.

FIG. 5 shows the fader control voltage in the embodiment of the present invention;
3 is a diagram showing the relationship between the output of a D/A converter 15 and the output of a gain control circuit 19. FIG. In FIG. 5, a is the fader control voltage, b is the output of the D/A converter 15, and c is the gain control circuit 1.
9, the vertical axis shows the voltage and the horizontal axis shows the rotation angle of the fader. The output of the gain control circuit 19 provides a control voltage that changes just by operating the fader once, as if the fader had been operated several times. Furthermore, according to the present invention, a plurality of comparators are used to compare the fundamental wave and the control voltage that determines the slice level, and the outputs are logically synthesized. Another important feature is that it can be blurred.

FIG. 6 is a diagram showing an example of a special effect obtained by the present invention, which changes as shown in FIG. 6 a-+f.

Changes in a+f can be made with a single fader operation. In this case, it is natural that the number of comparison circuits is increased compared to that shown in the present invention.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a special effect of a stripe wipe, FIG. 2 is a diagram for explaining how to make a conventional stripe wipe, FIG. 3 is a diagram showing the configuration of an embodiment of the present invention, and FIG.
The figure shows a part of the waveform of the main part of FIG. 3, and FIG. 5 shows the relationship among the fader control voltage, the output of the D/A converter 15, and the output of the gain control circuit 19 in FIG. , FIG. 6 is a diagram showing an example of special effects obtained by the present invention.

Claims (1)

[Claims] 1. When creating a stripe wipe special effect waveform, at least one horizontal comparison circuit that compares special effect waveforms synchronized with the horizontal period at a predetermined level to obtain an effect waveform that vertically divides the television screen; at least one vertical comparison circuit that obtains an effect waveform that horizontally divides the television screen by comparing special effect waveforms synchronized with the above at a predetermined level; and a stripe combining the outputs of the horizontal comparison circuit and the vertical comparison circuit. a logical operation circuit for obtaining a wipe effect signal; and means for generating a first slice level that varies stepwise from row to row of the stripes and varies continuously between one row of said stripes in response to a fader control voltage. means for synthesizing the first and second slice levels and supplying the synthesized slice level to one of the horizontal comparator circuit and the vertical comparator circuit; generating a third slice level according to the position of the stripe on the screen;
A special effects waveform generator comprising means for supplying the third slice level to the other of the horizontal comparison circuit and the vertical comparison circuit.