JPS60154782A - Device for preparing insertion picture signal - Google Patents

Abstract

PURPOSE:To realize a function which inserts a reduced screen on an ordinary screen by using one frame memory composed of a sequential access memory. CONSTITUTION:An image signal reaching an input terminal 10 is converted into a digital image signal by an AD converter 11, reduced and written by one field memory 12. Since one field memories 12 and 13 are composed of a sequential access memory, said memories are transferred to an output terminal by a clock from a control circuit 14 and then read out. One field memories 12 and 13 are connected by a control signal from a control circuit 15 by a switch circuit 16 and a clock is written in the prescribed position of the one field memory 13. A switch circuit 17 displays ordinary picture signals during a period except the time of displaying a reduced picture signal on the screen.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides an insertion image signal for inserting a screen reduced to a predetermined size at an arbitrary position on a television screen using a sequential access memory. Concerning the creation device - Structure of conventional example and its problems Traditionally, television receivers that have the function of displaying a reduced screen on a normal TV screen have a reduced screen as shown in Figure 1. The reduced screen is stored in a reduced screen forming circuit 1 equipped with a memory having a capacity corresponding to the size of the screen to be reduced,
The switching circuit 2 switches between the normal screen and the reduced screen,
A reduced screen was inserted into the normal screen.

However, with the recent development of semiconductor technology, large-capacity memories have become easily available, and TV reception is now equipped with one-frame memory, noise reduction function, and frame comb filter function to improve image quality. A machine is being considered.

Furthermore, in order to simplify the memory configuration as a one-frame memory, a one-frame memory configured with a sequential access memory instead of a random access memory is being considered.

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide an insertion image signal generation device having a function of inserting a reduced screen into a normal screen using a one-frame memory configured with a sequential access memory.

Structure of the Invention The present invention provides a first 1-field memory configured with a sequential access memory that stores a reduced video signal, and a reduced video signal stored in the first 1-field memory. a first control circuit for controlling movement at a predetermined position in one field memory;
The first
a second memory for storing the video signal stored in the field memory;
1-field memory; and a second control circuit that performs control to write the contents of the first 1-field memory to a predetermined position of the second 1-field memory.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 is a block diagram of an insertion image signal generating apparatus according to an embodiment of the present invention. In Figure 2, 11 is A/
A D converter, 12.13 is a one-field memory constituted by a sequential access memory, 14.15 is a control circuit, 16.17 is a switching circuit, and 18 is a D/A converter.

The operation of the insertion image signal generating device of this embodiment configured as described above will be described below.

The video signal arriving at the input end 1o is converted into a digital video signal by an A/D converter 11. Let the sampling frequency at this time be fs. This digital video signal is reduced and written into the one twist memory 12.

Writing and reading operations to and from the 1-field memory 12 will be explained. As shown in FIG. 3a, the size of the reduced screen is assumed to be reduced to H of the normal screen. i.e. horizontally,
% in both the vertical direction.

As shown in Figure 4, if the circles including double circles are sampling points even when sampling at sampling frequency fs, doubling the sambling period will make the double circles become sampling points, and the horizontal direction will increase by %. Thinned out. In the vertical direction, sampling is performed every other horizontal scanning line and thinned out to %. That is, the repetition frequency is set to fs/2 by the control circuit 14 for each horizontal scanning period as shown in FIG.
A write clock signal of 1 is supplied to the 1-field memory 12. Regarding the method of writing to the 1 field memory 12, in order to write the thinned out signal within the 1 field memory in a manner that corresponds to the reduced image, the thinned out 1
Once the video signal for one horizontal scanning line has been written to the first column of one field memory 12, the video signal for one horizontal scanning line is written to the first column at an appropriate period until the next horizontal scanning line's worth of video signal arrives. The video signal that has been thinned out is line-shifted to the second column directly below by a line shift signal from the control circuit 14, and the next thinned-out video signal for one horizontal scanning line is written in the first column. . The above-described operation is repeated, and one field's worth of thinned out signals is written at position D in FIG. 3.

Next, reading will be explained. 1 field memory 1
2.13 is composed of a sequential access memory as mentioned above, so it outputs the signal written in the position D in FIG. 3 near the input terminal by the clock from the control circuit 14. After moving to the position of FIG. 3A, near the edge, a read operation is performed.

When you try to display the reduced screen at the position A in Figure 3a on the gold plate, the corresponding 3rd field of the 1st field memory 13
It is necessary to write at position A in the figure. As mentioned above, the reduced image signal is stored in the third field memory 12.
Since it has been moved to the position A in the figure, a clock having a repetition frequency fs is supplied from the control circuit 14 to the one-field memory 12 for a period corresponding to A in FIG. 3A, and is read out. At the same time, the one-field memories 12 and 13 are connected by the switching circuit 16 in response to a control signal from the control circuit 15 for a period corresponding to A in FIG. 3a. Furthermore, the control circuit 15 determines that the repetition frequency is fs.
The clock is supplied to the 1-field memory 13 and written into a predetermined position (A in FIG. 3).

The 1-field memory 13 is read by being supplied with a repetition frequency clock from the control circuit 15. The switching circuit 17 is used to display normal image signals during periods other than when the reduced image signals are displayed on the screen, that is, in portions B, C, and D in FIG. 3a.

The periods corresponding to B, C, and D in Fig. 3d are for the A/D converter 1.
During the period in which the 1 output signal corresponds to A, one output signal of the 1 field memory 13 is switched by the control signal from the control circuit 15. The output signal of the switching circuit 17 is D
The signal is converted into an analog signal by the /A converter 18, and an X7 video signal including the reduced image signal is obtained at the output terminal 19. The other output signal of the 1-field memory 13 is returned to the 1-field memory 13 via the switching circuit 16, and is written and switched to the 1-field memory 13 again. By repeating this operation while displaying the reduced image, a reduced still image is obtained, and the reduced still image is inserted into the normal screen.

In the above explanation, we have taken as an example the case where the inserted image is displayed at the position A in Figure 3a, but it goes without saying that the inserted image is not limited to the position A, and it can be displayed not only in one place but in several places. It goes without saying that the present invention is also effective for display. Further, although the size of the inserted screen has been described using the normal screen A as an example, it is needless to say that the size of the inserted screen is not limited.

Effects of the Invention The insertion image signal generating device of the present invention includes a control circuit that generates a control signal for moving the video signal written in one field memory to a location near the output end, and a control circuit that generates a control signal for moving the video signal written in one field memory to a location near the output end. By providing a control circuit for writing data into the memory, it is possible to create an insertion image signal using a single frame memory composed of a sequential access memory, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a conventional insertion image signal generation device, FIG. 2 is a block diagram of an insertion image signal generation device in an embodiment of the present invention, and FIG. 3 is a diagram showing the correspondence between a screen and one field memory. , FIG. 4 is a diagram showing sampling points, and FIG. 6 is a diagram showing clock timing. 12.13...1 field memory, 14, 1
6...Control circuit, 16.17...Switching circuit. Name of agent: Patent attorney Toshio Nakao and one other IR
I Figure 2 Figure 4- Figure 3 (Q,) Figure 4 Figure 5

Claims (1)

[Claims] A first 1-field memory configured with a sequential access memory that stores a reduced video signal; and a reduced video signal stored in the first 1-field memory is stored in the first 1-field memory. a first control circuit that controls movement at a predetermined position; and a second one-field memory that is composed of a seven-dimensional access memory and stores the video signal stored in the first one-field memory. and a second control circuit for controlling whether or not to write the contents of the first one-field memory to a predetermined position of the second one-field memory.