JP3216359B2 - Display control device for child image - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a child image display control device that superimposes and displays a child image such as a counter program on a partial area on a screen such as a V or VTR.

[0002]

2. Description of the Related Art In recent TVs and VTRs, a picture-in-picture function (hereinafter, referred to as a program) for displaying a counter program or the like in a corner of a screen is provided.
P (in short). In a TV commercialized with a P-in-P, which is currently commercialized, humans control the on / off of the P-in-P using a remote controller or the like. Also, when important information in the parent image is hidden by the display of the child image, a person manually moves the display area of the child image or deletes the child image.

Here, a block diagram of a general P-in-P is shown in FIG. In the figure, 1 is an A / D converter for converting a TV signal for a child image into a digital signal, 2 is a memory storing compressed data, 3 is an image compressor for performing image compression using the memory 2, and 4 is a compression device. A D / A converter 5 for returning image data to an analog signal is a switcher for switching between a parent image and a child image.

[0004]

In the conventional P-in-P, the parent image is difficult to see due to the display of the child image, and the troublesome manual operation for viewing important information in the hidden parent image is difficult. Because of that, it is not really used much. In addition, even in the case of demonstration effects in stores, the present situation is that display of a child image is almost no longer novel.

The present invention has been made based on such a background, and provides a child image display control device capable of grasping child image information while minimizing loss of information in a parent image. The purpose is to do.

[0006]

According to a first aspect of the present invention, a child image different from the parent image is superimposed in a partial area on a screen displaying the parent image. In a child image display control device for displaying in a paused state, a frequency component detecting unit for detecting a frequency component of an image signal of the parent image on the screen, and at least two or more partial regions on the screen. Comparing means for comparing the magnitude of the frequency component of the image signal of the parent image detected by the frequency component detecting means, based on the comparison result of the comparing means, the frequency component is small within the area on the screen Display control means for superimposing and displaying the child image.

According to a third aspect of the present invention, there is provided a timing detecting device for detecting a timing at which at least one of a predetermined image pattern and a predetermined audio pattern is generated based on at least one of the image signal and the audio signal of the child image. The display control means automatically superimposes the child image on the parent image at a timing when the timing detection means detects at least one of the predetermined image pattern and the predetermined sound pattern. Is displayed.

[0008]

According to the present invention, the frequency component of the image signal of the parent image on the screen is examined, and the child image is displayed at a portion where the frequency component is low, that is, at a place where the picture is not fine or where the picture changes little. Thus, the lack of information of the parent image is minimized. Further, at a timing when the timing detecting means detects at least one of the predetermined image pattern and the predetermined sound pattern from at least one of the image signal and the audio signal of the child image, the display control means sets the child image to the parent image. By superimposing and displaying automatically, a more efficient child image display can be performed, and the commercial value is also increased.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In the present invention, in order to display a child image at a position that does not disturb the parent image as much as possible, it is assumed that the frequency components of the entire parent image are examined. For example, a plurality of pixels constituting a screen may be used. There is a method of summing up the difference between the frequency components of adjacent pixels in the image and detecting the state of change of the parent image on the screen or the distribution of the low frequency component region. FIG. 1 shows the concept.

A certain area on the screen (a range surrounded by a dotted line)
In order to check the change of the parent image on a, each pixel (P
1, P2, Pn) in order and sum the absolute value of the difference from the immediately preceding pixel (| P2-P1 | + | P3-P2
| ++++ Pn-1−Pn |). Similarly, the next line is also summed (| Q2-Q1 | + | Q3-Q2
| + | Qn−1−Qn |) and add the sum of the lines P1 to Pn (there is no correlation between Pn and Q1, so there is no difference).

As shown in FIG. 2, if the display position of the P-in-P is selected from, for example, four corners of the screen, the sum of the differences is calculated for the four corners and the smallest one is selected. The child image can be displayed at a position where the child image does not appear. For example, an image such as a blue sky, which is a parent image displayed in the area a, has the least change in frequency components. Therefore, if a child image is displayed in the area a, all important information portions of the parent image are removed. It will be alive.

FIG. 3 is a block diagram of a child image display control device according to the embodiment. This embodiment relates to a method for detecting and summing the difference between the frequency components of adjacent pixels as described above, and includes an adder 10, registers 11 to 16, a negative number generator 17, and a comparator 18. Register (1) 1
1 temporarily stores the frequency component of the adjacent pixel, and the register (2) 12 temporarily stores the difference between the frequency components of the adjacent pixels. The registers (3) 13 to (6) 16
For each of the display candidate areas a to d of the child image (see FIG. 2), the sum of the difference between the frequency components of adjacent pixels is stored. The number of bits (the number of digits) required for the registers (3) 13 to (6) 16 varies depending on the size of the range in which the difference is viewed and the degree of change of the pixel.

Next, the operation will be described. First, P1 (see FIG. 1) is converted to a negative number (here, 2's complement) by a negative number generator 17 and stored in the register (1) 11. And
Adder 10 adds P2. MSB of the result obtained
By setting the (most significant bit) to 0, the absolute value is stored in the register (2) 12. At the same time, P2 is set to a negative number and stored in the register (1) 11. Then, the register (2) 12 and the register (3) 13 (0 is initially set) are added, and the result is stored in the register (3) 13. Hereinafter, similarly, P3 and -P2 may be added, and the absolute value of the result may be added to the value of the register (3) 13.

When all the differences of the display candidate areas a to d are summed up, the values of the registers (3) 13 to (6) 16 are compared by the comparator 18 to determine which position has the largest pixel change amount. It can be detected whether it is small. Then, as described above, the child image may be displayed in the display candidate areas a to d having the smallest pixel change amount.

FIG. 4 shows a case where pixel data is 2 bits.
FIG. 4 is a circuit diagram showing a specific example of the block diagram shown in FIG. 3;
Reference numeral 9 denotes a selector. The comparator 18 is omitted.

Here, it is not necessary to always display the child image, and it is effective to display the important image only when important information in the child image is output. In that case, when it is displayed, the simplest way is to detect that the sound has increased. For example, when the child image is a sports program such as a baseball game or a soccer game, when a score is obtained, the shouting is increased. However, since this alone may cause a malfunction, the sound signal of the child image can be more reliably detected by applying a band-pass filter to the sound signal at several frequency points to determine the sound. If a buffer memory of P in P is prepared for several tens of fields, the broadcast can be delayed by several seconds by always storing the buffer memory as FIFO (first in first out). Then, it becomes possible to play back a few seconds before the shout.

Further, for example, when the child image is a foreign film, a sports program, or the like, the superimposed subtitles and the score display superimposed in the image have a steep change unlike pictures such as landscapes. Therefore, if the image signal of the child image is differentiated by the high-pass filter, it can be understood that the subtitle superimposition and the score display are superimposed. In order to simplify the operation, for example, when the difference from the frequency component of the adjacent pixel exceeds a certain value, it is determined that the subtitle superimposition or the score display is inserted. Of course, there are many malfunctions as it is,
More accurate detection can be made by making full use of such means as pattern recognition. In addition, news and weather forecasts often have the same logo and location every time,
It is relatively easy to detect these logos and display positions and superimpose news, weather forecast, and the like as child images on the display screen of the parent image.

If such P-in-P becomes widespread, T
It seems that the V station will also broadcast marks such as logos and barcodes that are easy to detect. For example, it is also possible to attach an easily identifiable mark to an emergency broadcast, extraordinary news, or the like, and to output it in a child image when the broadcast starts. As a method for detecting the frequency component of the image signal of the parent image on the screen, in addition to the method described in the embodiment, for example, a method of performing a spectrum analysis by Fourier transform may be used.

[0019]

According to the first and second aspects of the present invention, the frequency component of the image signal of the parent image on the screen is examined, and a portion having a low frequency component, that is, a place where the picture is not fine or a change in the picture is obtained. By displaying the child image in a place where there is little, the loss of information of the parent image is minimized, so that the characteristics of P-in-P can be maximized.

According to the third and fourth aspects of the present invention, the timing detecting means detects at least one of a predetermined image pattern and a predetermined audio pattern from at least one of the image signal and the audio signal of the child image. Then, the display control means superimposes the child image on the parent image and automatically displays the superimposed image, so that the child image can be displayed more efficiently and the commercial value is increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a method of detecting a frequency component of an entire parent image from a sum of frequency component differences of an image signal for adjacent pixels.

FIG. 2 is a schematic diagram illustrating a change in frequency component for each display candidate region of a child image on a screen.

FIG. 3 is a block diagram of a child image display control device according to the embodiment of the present invention.

FIG. 4 is a circuit diagram showing a specific example of a block shown in FIG. 3 when pixel data is 2 bits.

FIG. 5 is a block diagram of a general P-in-P.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 adder (frequency component detecting means component) 11 to 16 register (frequency component detecting means component) 17 negative number generator (frequency component detecting means component) 18 comparator (comparing means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/445-5/45 H04N 5/262-5/278 H04N 7/18

Claims (4)

(57) [Claims] 1. A child image display control device for superimposing and displaying a child image different from the parent image in a partial area on a screen where a parent image is being displayed, wherein the parent image on the screen is displayed. Frequency component detecting means for detecting a frequency component of the image signal of the image signal; and at least two or more partial regions on the screen, the magnitude of the frequency component of the image signal of the parent image detected by the frequency component detecting means. And a display control unit that superimposes and displays the child image in an area on the screen where the frequency component is small, based on the comparison result of the comparison unit. Display control device for child images. 2. The child image display control device according to claim 1, wherein said frequency component detection means sums the difference between the frequency components of adjacent pixels among a plurality of pixels constituting said screen. . 3. The display device according to claim 1, further comprising a timing detection unit configured to detect a timing at which at least one of a predetermined image pattern and a predetermined audio pattern occurs based on at least one of the image signal and the audio signal of the child image. The control unit superimposes the child image on the parent image at the timing when the timing detection unit detects at least one of the predetermined image pattern and the predetermined audio pattern, and automatically displays the child image. The child image display control device according to claim 1. 4. The predetermined image pattern is a character image such as a title image of a broadcast program or a superimposed subtitle image, and the predetermined sound pattern is a theme song of a broadcast program, a call of a program entrant, 4. The child image display control device according to claim 3, wherein the sound is a sound such as a time signal.