JPH01187593A - Displaying area designating device - Google Patents

Abstract

PURPOSE:To designate a displaying area in real time by obtaining the absolute values of outputs by subtracting data indicating the central position of the displaying area from count values indicating the displaying position of a screen and outputting signals designating the displaying area by subtracting the data indicating the half value of the width of the displaying area from the absolute values. CONSTITUTION:A horizontal and vertical counters 11 and 14 which indicate the horizontal and vertical positions of a picture are provided and, by subtracting the data 'X1' and 'Y1' indicating the central position of a displaying area in the horizontal and vertical directions from the outputs of the counters 11 and 14, the central position of the displaying area is determined. Then the absolute value of each subtracted output is obtained and the horizontal and vertical widths of the displaying area are determined by subtracting the data 'X2' and 'Y2' indicating the half values of the horizontal and vertical widths of the displaying area from the absolute value outputs. After determining the horizontal and vertical widths, a horizontal and vertical displaying area designating signals Sh and Sv are produced. therefore, almost all processes can be performed by means of hardware and the displaying area can be designated in real time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a display area specifying device for specifying a display area for displaying a predetermined image on a screen.

(Prior Art) In recent years, as the tendency to use television receivers as monitor devices has increased, special display modes for images have been required. Here, the special display mode includes, for example, an enlarged display mode in which a part of the screen is enlarged and displayed, and a picture-in-picture display mode (hereinafter referred to as PIF mode) in which a child image is displayed in a part of a parent image. , a channel search display mode that divides and displays images of multiple channels at equal sizes, etc.

In order to realize the special display mode as described above, it is necessary to specify a display area in which an enlarged image or the like is to be displayed.

In conventional display area specifying devices, the display area is specified by the CPU according to the display position.

However, in such a configuration, the calculations used by the CPU to specify the display area according to the display position are complex, so it may not be possible to specify the display area in real time. For this reason, in the conventional display area specifying device, the calculation of the CPU lags behind the image scanning, and the image may not be displayed in the desired display area.

(Problems to be Solved by the Invention) As described above, in the conventional display area designation device,
Since the display area is specified by CPU calculation, it is not possible to determine the display area according to the display position in real time, and it may not be possible to display the image in the desired display area. Therefore, an object of the present invention is to provide a display area specifying device that can specify a display area in real time and can always display an image in a desired display area.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention subtracts data indicating the center position of the display area from a count value indicating the display position on the screen, and calculates the result of this subtraction. A signal specifying the display area is output by taking an absolute value and subtracting data indicating a value of half the width of the display area from this absolute value output.

(Function) According to the above configuration, by subtracting data indicating the center position from the count value, when this subtraction output becomes "0", the center position of the display area is determined, and the absolute value of this subtraction output By subtracting data representing half of the width of the display area from it, when the subtraction output becomes "O", both ends of the display area are determined. Therefore, the display area can be specified by the latter subtraction output.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention.

The configuration and operation of FIG. 1 will be explained below with reference to FIGS. 2 to 6. In the following explanation, the display area specifying operation in FIG. 1 will be explained using as an example the display area specifying operation in special reproduction modes such as enlarged display mode, PNP display mode, and channel search mode.

(1) First, specification of the display area of the enlarged image in the enlarged display mode will be explained.

This designation is made as follows.

In FIG. 1, numeral 11 is a horizontal counter that outputs an 8-bit count value indicating the horizontal position of the screen. The horizontal counter 11 is reset by the horizontal synchronization pulse H8 supplied to the terminal 13 when it counts 128 system clocks CK supplied to the terminal 12. 14 is a vertical counter that outputs an 8-bit count value indicating the vertical position of the screen. When the vertical counter 11 counts 256 horizontal synchronizing pulses H8, the vertical counter 11
It is reset by the vertical synchronization pulse vS supplied to 5.

FIG. 2 shows the relationship between the count values of the counters 11 and 14 and the horizontal and vertical positions of the screen. In the figure, IH is one horizontal scanning period, and 1v is one vertical scanning period.

The count output of the horizontal counter 11 is sent to the adder circuit 16.
is supplied to This addition circuit 16 includes a horizontal counter 11
The latch data “X” of the latch circuit 17 is obtained from the count output of
l" to obtain a 9-bit subtraction output. The latch circuit 17 holds 8-bit data "Xl" indicating the horizontal center position of the display area. This data "Xl"
Latch pulse LP given from PU 18 via mode setting circuit 19 and output from mode setting circuit 19
It is held in the latch circuit 17 according to I.

As shown in FIG. 3(a), the subtraction output of the adder circuit 16 is the count value of the horizontal counter 11 shifted by "Xl" in the negative direction, so that the count value of the horizontal counter 11 is "Xl". When , it becomes “0”. therefore,
When the subtraction output of the adder circuit 16 is "0", the horizontal center position of the display area is determined.

The subtracted output of the adder circuit 16 is supplied to the absolute value circuit 2o, and the absolute value is taken. As a result, the negative value portion of the subtracted output of the adder circuit 16 becomes a positive value, as shown in FIG. 3(b).

FIG. 4 shows an example of a specific configuration of the absolute value circuit 20. The illustrated absolute value circuit 2o is constituted by a two-man exclusive OR circuit. The eighth bit of the subtracted output of the adder circuit 16 is supplied to one input terminal of this exclusive OR circuit. The other terminal is supplied with data of the lower bits from the 7th bit of the subtracted output. With this data supply configuration, the lower 7 bits of data output from the exclusive OR circuit exhibit a positive value. As a result, as shown in FIG. 3(b), the negative portion of the subtracted output becomes a positive value. However, if you do this, the subtraction output will be "not only when the horizontal counter 11 is "Xl" but also when it is "Xl-1".
Therefore, in this embodiment, the horizontal center position is actually set between "Xl" and "Xl-1".This is because the horizontal width This is very effective for specifying.

The absolute value output of the absolute value circuit 20 is supplied to an adder circuit 21 . This adder circuit 21 outputs 9-bit data by subtracting 8-bit latch data "X2" latched in the latch circuit 22 from the absolute value output of the absolute value circuit 20. Latch data “X2” of latch circuit 22
” is data indicating half the width of the display area in the horizontal direction.

This data "X2" is applied from the CPU 19 to the latch circuit 22 via the mode setting circuit 19, and is latched by the latch circuit 22 by the latch pulse LP2 output from the mode setting circuit 19.

-8= Through this subtraction process, the absolute value output of the absolute value circuit 20 is
As shown in FIG. 3(c), the overall value decreases by "X2". Points at which such subtraction output becomes "0" determine both ends of the display area in the horizontal direction.

As shown in FIG. 3(b), the absolute value output of the absolute value circuit 20 is symmetrical with respect to the horizontal center position of the display area. Then, the subtraction output of the adder circuit 21 is:
It becomes "0" at a point that is "X2" away from this center position, that is, an intermediate position between "Xl" and "Xl-1" to the left and right.

If the center position is "Xl", the horizontal width of the display area is "X2-1" on the left side of the center position, and "X2-1" on the right side of the center position.
X2", making the left and right sides uneven. Therefore, in this embodiment, as described above, the center position is set to "Xl" and "Xl-1
” is set in the middle.

In the subtraction output of the adder circuit 21 as described above, when looking at the 8th bit which is the sign bit, it becomes "1" in the display area as shown in FIG. 3(c). Therefore, these 8 bits By using the eye data, a horizontal display area designation signal sh can be obtained.

Although the details of the vertical display area designation signal Sv are omitted,
Just like the horizontal display area designation signal sh, it is obtained by processing the count output of the vertical counter 14 by the subtraction circuits 2B and 26, the latch circuits 24 and 27, and the absolute value circuit 25.

Note that Yl and Y2 are data indicating the vertical center position and half the vertical width, respectively.

The horizontal and vertical display area designation signals S shown in FIG.
h, indicates Sv. These display area designation signals Sh and Sv are
After the AND circuit 28 performs the logical product, the signal inversion circuit 2
9. In the enlarged display mode, the signal inversion circuit 29 supplies the input signal as it is to the switch circuit 30 without inverting it. This switch circuit 30 is
When the display area designation signals Sh and Sv are at the “1” level,
Select the video signal for the enlarged image supplied to the input terminal 31, and if the level is "0", select the video signal supplied to the input terminal 32, that is, the video signal displayed in the part other than the enlarged display area. select. This selection output is the output terminal 33
The signal is then supplied to an image display circuit (not shown) and used for image display.

(2) Next, the operation of specifying the display area in the PIF display mode will be explained.

The processing in this case is exactly the same as in the enlarged display mode described above. In this case, the center position of the display area of the child image is determined by the data “Xi” set in the latch circuit 17.24.
, "Yl". Also,
The area ratio of the display area of the child image and the parent image is determined by the latch circuit 22.
．． It can be selected as appropriate by data “X2” and “Y2” set in 27. Furthermore, even in this enlarged display mode, the signal inversion circuit 29 passes the output of the AND circuit 28 as it is without inverting it. In addition, the input terminal 31
．． 32 are supplied with video signals of a child image and a parent image, respectively.

(3) Finally, specifying the display area in channel search mode will be explained.

Now, as shown in Figure 6(a), set the screen horizontally.

Channel search that allows you to search for images from 9 channels by dividing vertically into 3 areas and setting 9 areas R1 to R9, and displaying images from different channels in each area. Explain the mode. Note that the video signals of each channel displayed in each region R1 to R9 are time-division multiplexed in advance, and are sent to the input terminal 31 in FIG.
is supplied to The input terminal 32 is supplied with a video signal that is completely unrelated to the channel image and shows only a certain color, for example.

By the way, as mentioned above, in the channel search mode, there is a case where channel images are displayed in all nine areas as shown in FIG.
) to (d), there are cases where an image is attached only to an area other than the shaded area. In the latter case, the display area (other than the shaded area) should be aligned with one center position and one
Two horizontal lines.

The vertical width cannot be specified; the display area must be divided into two or more areas, and the center position and width in the horizontal and vertical directions must be specified for each divided display area.

However, if we pay attention to the shaded areas in Fig. 6(b) to (d),
This shaded area is one center position and horizontal.

This can be specified by specifying the vertical width.

Therefore, in this embodiment, when performing a channel search mode as shown in FIGS. 6(b) to 6(d), signals Sh and Sv specifying the shaded portion are generated and sent to the signal inverting circuit 29. It is specified by inverting it with . Whether or not the signal inversion circuit 29 is caused to perform an inversion operation is controlled by the CPU 18 via the mode setting circuit 19.

As detailed above, in this embodiment, the screen is horizontal.

Horizontal and vertical counters 11 and 14 are provided to indicate the vertical position,
From the count outputs of these counters 11 and 14, data “Xl” and “
Determine the center position of the display area by subtracting "Yl", take the absolute value of each subtraction output, and subtract data "X2" and "Y2" indicating half the horizontal and vertical width from these absolute value outputs. Accordingly, the horizontal and vertical widths of the display area are determined, and the horizontal and vertical display area designation signals Sh and Sv are generated.

According to such a configuration, it is possible to perform most of the processing by hardware, and in this case, the CPU 18 inputs data “Xl” to the latch circuits 17, 22, 24°27.
X2”, “Yl”.

All you need to do is to latch “Y2”, so
Display area can be specified in real time. Thereby, the image can always be displayed in the desired display area.

In addition, in the previous embodiment, the case where this invention is implemented by hardware was explained, but it goes without saying that it may be implemented by software of the CPU 18.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a display area specifying device that is capable of specifying a display area in real time.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
3 and 3 are diagrams for explaining the operation of FIG. 1, and FIG.
This figure is a circuit diagram showing an example of a specific configuration of the absolute value circuit shown in FIG. 1, and FIGS. 5 and 6 are diagrams showing the operation of FIG. 1. 11... Horizontal counter, 12.13.15... Terminal, 14... Vertical counter, 16, 21, 23.26.
...Addition circuit, 17, 22, 24.27...Latch circuit, 18...CPU, 19...Mode setting circuit, 2
0゜25... Absolute value circuit, 28... AND circuit, 2
9... Signal inversion circuit, 30... Switch circuit, 31
．． 32...Input terminal, 33...Output terminal. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Scope of Claims] A display area specifying device for specifying a display area for displaying a predetermined image on a screen, comprising a count means for outputting a count value indicating a display position of the screen; a first data holding means for holding data indicating the center position; a second data holding means for holding data indicating half the width of the display area; a first subtraction means for subtracting the data held in the data holding means; an absolute value means for taking the absolute value of the subtracted output of the first subtraction means; An image display control device comprising: second subtraction means for outputting a display area designation signal by subtracting data held in the data holding means.