JPS6320072B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a television screen wipe effect generating device, and more particularly to a novel soft border wipe effect generating device that blurs the border line.

Conventional border wipe effect generating devices generally use a slicer to extract a point between two points on the amplitude of a soft wipe waveform, gate a border signal such as a back color, and use it as a boundary line. At this time, the slicer output signal has an extremely faster rise time than the period of the color subcarrier signal (approximately 0.28μsec), so when gating the border signal including the color subcarrier signal, the phase of the color subcarrier signal is significantly changed. This caused the colors reproduced on the receiver screen to partially change. Furthermore, as is well known, the phase of the color subcarrier is reversed for each horizontal scanning line, but these points act synergistically, causing flickering and color changes at the border, which are unsightly. It had become a phenomenon.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a soft border wipe device that does not cause color disturbance or flickering at the border between a border signal and other screens, except for the drawbacks of the prior art.

According to the present invention, a soft border wipe device is obtained in which a gate signal for gating a border signal is generated by differentiating a soft wipe waveform, and a linear gate circuit is used as a circuit for gating the border signal. In the soft border wipe device according to the present invention, the gate signal for inserting the border signal has an appropriate rise time, that is, it has a rise time of 1/2 cycle or more of the color subcarrier, so that the border signal does not overlap at the border. The phase of the included subcarriers does not change abruptly. This corresponds to limiting the color subcarrier frequency components in the gate signal. Furthermore, since the gate signal has a rise time, the border signal and the video signal overlap at the boundary, so that blurring effects, color disturbance, and zigzag appearance do not occur.

Next, the present invention will be described in detail with reference to the drawings showing one embodiment of the present invention. FIG. 1 is a diagram showing one embodiment of the present invention, and FIG. 2 is a waveform diagram of each main part of FIG. 1. In Figure 1, input terminals 1 and 2
A video signal to be synthesized is supplied from the . Two video signals v ₁ and v ₂ supplied by the rear gate circuit 3 are combined in accordance with a gate signal C ₄ from the slice circuit 4. The combined video signal v ₃ is supplied to the linear gate circuit 5 to insert a border signal v ₆ between the combined video signal v ₁ and video signal v ₂ . In the border signal generation circuit 6, a border signal _v6 containing a color subcarrier representing a desired color is generated and sent to the linear gate circuit 5. The border signal generating circuit 6 has the same function as a conventional back color generating circuit.

The soft wipe waveform generation circuit 7 generates a soft wipe waveform v ₇ whose rising and falling edges are sloped.
is created and sent to the slice circuit 4 and the differentiation circuit 8. The slicing circuit 4 slices the waveform v ₇ at a predetermined level to generate a gate signal C ₄ for combining the video signals v ₁ and v ₂ . The differentiating circuit 8 differentiates the soft wipe waveform v ₇ to generate a gate signal for gating the border signal, and sends the differentiated waveform to the rectifier circuit 9 . Although FIG. 2 only shows waveforms in the horizontal direction, it is also performed in the vertical direction. The rectifier circuit 9 matches the polarities of the differential waveforms to generate a gate signal _C9 for inserting the border signal _v6 at the boundary of the synthesized video signal _v3 . An output video signal _v5 with a border signal inserted at the boundary of the composite screen is obtained from the linear gate circuit 5, and is sent to the output terminal 10.
is supplied to

In the present invention, as shown in FIG. 2, the soft wipe waveform _V7 is differentiated to create the border waveform insertion gate signal _C9 , so the output video signal _V5
Here is the inserted border signal _V6 and video signal
Since the boundary between v ₁ and v ₂ does not change sharply, there is no sudden change in the phase of the subcarrier included in the border signal v ₆ , which may cause screen color disturbance or flickering at the boundary. Never. Note that if the soft wipe waveform generating circuit 7 directly sends out the gate signal _C4 for synthesizing the video signals _v1 and _v2 separately from the soft wipe waveform _v5 , the slice circuit 4 is not necessary.

The differentiating circuit 8 may be used for differentiating a wipe waveform with a horizontal period using a normal differentiating circuit, but for differentiating a wipe waveform with a long vertical period, a vertical period differentiating means using, for example, a plurality of horizontal delay lines may be used. Just use it. FIG. 3 is a diagram showing an example of a vertical period differentiation circuit, which is composed of one horizontal period delay means 11, 12, coefficient units 13, 14, 15, and subtraction means 16. Figure 4 shows the linear gate circuit 3 of Figure 1,
5, each input is a gate circuit 1.
7 and 18, and are sent to a mixing circuit 20 in response to gate signals whose polarities are reversed by an inverter 19, where they are combined.

In the configuration diagram shown in Figure 1, there is actually a clamp circuit for reproducing the DC component of the video signal and a circuit for inserting blanking into the wipe waveform, and these are the same as the conventional wipe device and border wipe device. be.

In the video signal _v5 in Figure 2, the width of the border signal _v6 corresponds to the width of the border, and the border signal
The magnitude of the rise time of _v6 determines how blurred the boundary is. The width of the border and the degree of blur can be determined by changing the soft width of the waveform in the soft wipe waveform generator.

As explained above, the present invention uses a differentiating circuit to obtain a border waveform to obtain a border wipe with a blurred border, thereby eliminating color disturbances in the border portion caused by partial phase changes of color subcarriers. This has the effect of preventing flickering.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing waveforms of the main parts of FIG. 1, and FIG. 3 is an example of a vertical period differentiation circuit of the differentiation circuit 8 in FIG. 1. Figure 4 shows the linear gates 3 and 5 in Figure 1.
Configuration diagram. In the figure, 3, 5... linear gate circuit,
4... Slice circuit, 6... Border signal generation circuit, 7... Soft wipe waveform generation circuit, 8... Differential circuit, 9... Rectifier circuit, 11, 12... 1H delay circuit, 13, 14, 15... ...Coefficient unit, 16...
Subtraction circuit, 17, 18... Gate circuit, 19...
Inverter, 20... mixed circuit.

Claims (1)

[Claims] 1. means for generating a soft wipe waveform whose waveform has a sloped rise and fall; a slicing circuit which slices the soft wipe waveform to generate a first gate signal whose rise and fall are steep; The first step is to synthesize a plurality of video signals using the gate signal as a control signal to create a composite video signal.
a linear gate circuit, a means for generating a border signal to be inserted at the boundary of a plurality of video signals in the composite video signal, and differentiation processing and subsequent rectification processing of the soft wipe waveform so that rising and falling edges are at least colored. means for creating a second gate signal having a slope of 1/2 or more of the subcarrier period for inserting the border signal at the boundary of a plurality of video signals; the combined video signal, the border signal, and a control signal; and a second linear gate circuit that receives the second gate signal and inserts the border signal at the boundary of the plurality of video signals.