JPH05328160A - Automatic changeover device for video display size - Google Patents

Abstract

PURPOSE:To conduct the changeover applied to a television receiver or the like to automatically apply changeover control to a video display size in accordance with a video signal. CONSTITUTION:A maximum brightness value detection section 2 detects a maximum brightness in a line designed by a line number designation section 1 designating a line number for each of 10 lines. A video start line identification section 3 compares the detected maximum brightness of a preceding line with the maximum brightness of a current line and identifies the current line as a video start line when the difference is a threshold level or over. A video end line identification 4 identifies similarly a video end line. A video line number calculation section 5 calculates a video line number from the difference between the video start line number and the video end line number. A video mode identification section 6 identifies the video mode of an input video signal from the video line number, and a video display size changeover section 7 applies changeover control to a video display size onto a CRT automatically to an optimum size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a television (TV).
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video display size automatic switching device used for a receiver or the like and capable of automatically switching a video display size according to a video signal.

[0002]

2. Description of the Related Art Conventional TV receivers have been unable to enlarge or reduce the displayed image vertically and horizontally. Therefore, when an attempt is made to view a Vista-sized image such as movie software on this TV receiver, an image display in which the upper and lower parts are masked by black bands (see FIG. 2) causes the black bands to be annoying.

Recently, TV receivers have finally appeared which are capable of vertically and horizontally enlarging / reducing displayed images. Most of these TV receivers have an aspect ratio of 1
It is equipped with a 6: 9 horizontally long display, and can display images with a conventional aspect ratio of 4: 3, Vista-sized images, etc. on the horizontally long screen in an optimal image display size. (If the input is a Vista-size video signal, only the original video part can be displayed in full screen, and the video without black bands at the top and bottom can be displayed.)

However, in order for the viewer to use the image display size switching function of the TV receiver, the viewer himself / herself performs the switching operation of the size switching knob provided in the TV receiver in accordance with the image each time. It had to be done in, and was troublesome.

[0005]

The problem to be solved by the present invention is to provide a switching device capable of automatically switching the video display size in accordance with a video signal without requiring the viewer to perform the switching operation by himself / herself. What kind of measures should be taken to achieve this?

[0006]

In order to solve the above problems, the present invention provides a line number designating section for designating a line number of a video signal input, and a maximum luminance within one line of the designated line number. The brightness maximum value detection unit that sequentially detects the values and the detected brightness maximum values of the previous line and the current line are compared, and when the difference is equal to or more than a predetermined threshold, the video start line and the video end line are A line identification section for identifying, a video line number calculation section for calculating the number of video lines from the difference between the line number of the video start line and the line number of the video end line, and the video signal input video from the video line number A video mode identification unit for identifying the mode, and a video display size switching unit for automatically switching the video display size on the display unit to a predetermined size according to the identified video mode. There is provided a video display size automatic switching apparatus, characterized in that more configurations.

[0007]

EXAMPLES First, an outline of the examples will be described. Here, consider a case where signals of two types of video modes, that is, a video signal having an aspect ratio of 4: 3 and a video signal having a vista size are supplied. Now, assume that a video signal of a Vista size as shown in FIG. 2 is input. All lines in one field of this image (here, all lines are 262.5 lines)
When the maximum luminance value of each line is obtained by sequentially specifying
The result shown in is obtained.

In a Vista-size image, the boundary between the portion masked by the black band (the hatched portion in FIG. 2) and the original image signal portion is generally within the range of line numbers 0 to 100 on the upper side ( The upper boundary line is the video start line),
It is expected that the lower side is within the range of line numbers 160 to 260 (the lower boundary line is the video end line).

Therefore, in the present embodiment, in order to find the boundary line efficiently in a short time, all the lines are not specified to obtain the maximum brightness value, but the lines within the above range are specified for each predetermined line (here Then, every 10 lines are specified), and the maximum luminance value in each line of the specified lines is obtained. And the previous line (10 lines before)
If the difference between the maximum luminance value and
Any line between the line before the line and the line currently specified is regarded as the boundary, and the line currently specified is detected as the boundary line. From the line numbers of the detected upper and lower boundary lines, the range in which the image exists (hereinafter,
Call the number of video lines).

According to this method, the switching device of the embodiment repeatedly calculates the number of video lines, and if the calculated number of video lines becomes a stable value for a predetermined period, the video display size is changed based on the number of video lines. Size switching control is performed on the display unit so that the size is optimal. The above is the outline of the embodiment.

Next, the details of the embodiment will be described with reference to FIG. 1 which is a functional block diagram, FIG. 4 which is a flow chart showing a method for calculating the number of video lines, and FIG. 5 which is a flow chart showing a method for controlling switching of a video display size. Will be explained together. Figure 1
In FIG. 1, 1 is a line number designating section that designates a line number for every 10 lines, and 2 is a maximum luminance value detecting section that detects a maximum luminance value in the designated line. 3 is
A video start line discriminating unit that discriminates the video start line when the detected maximum luminance values of the previous line and the current line are compared and the difference is equal to or more than a threshold value, and 4 is a video start line discriminating unit. Similarly, it is a video end line identification unit for identifying a video end line. Reference numeral 5 is a video line number calculation unit that calculates the number of video lines from the difference between the line number of the video start line and the line number of the video end line, and 6 identifies the video mode of the input video signal from the number of video lines. It is a video mode identification unit that does. 7 is a CRT which is a display unit according to the identified video mode.
This is a video display size switching unit for automatically switching and controlling the video display size above (aspect ratio 16: 9) to the optimum size.

First, a method for calculating the number of video lines, which is performed between the line number designation unit 1 and the video line number calculation unit 5, will be described. In FIG. 4, in order to obtain the video start line number, steps 101 to 1 are initially set.
In 03, the designated line number, the video start line number, and the maximum luminance value 10 lines before are set to 0 (operation in the video start line identification unit 3 in FIG. 1).

In step 201, a line number is designated for every 10 lines (operation in the line number designating section 1), and in step 202 the maximum luminance value in one line of the designated line number is obtained (in the maximum luminance value detecting section 2). Behavior). Step 301
In steps 304 to 304, the maximum luminance value of the current designated line obtained in the previous stage and the maximum luminance value of the previous designated line (10 lines before) are compared. If the difference is equal to or more than a predetermined threshold value, the current designated line number is determined. Set the video start line number and proceed to step 401. If the difference is smaller than the predetermined threshold value, the current designated line number is set as the previous designated line number (the maximum luminance value of the current designated line is set as the maximum luminance value of the previous designated line), and the line number is 100 or more. If there is, the process proceeds to step 401, and if the line number is smaller than 100, the process returns to step 201 (operation in the video start line identification unit 3).

In steps 401 to 403, in order to obtain the video end line number, the designated line number and the video end line number are initially set to 260, and the maximum luminance value 10 lines before is set to 0 (video end). Operation in line identification unit 4). In step 501, the line number is designated in reverse for every 10 lines (operation in the line number designation unit 1), and in step 502 the maximum luminance value in one line of the designated line number is obtained (the maximum luminance value detection unit 2).
Operation).

In steps 601-604, the maximum brightness value of the current designated line obtained in the preceding stage is compared with the maximum brightness value of the previous designated line. If the difference is not less than a predetermined threshold value, the current designated line number is determined. The video end line number is set and the process proceeds to step 701. If the difference is less than the predetermined threshold,
The current designated line number is the previous designated line number (the maximum luminance value of the current designated line is the maximum luminance value of the previous designated line),
If the line number is 160 or less, the process proceeds to step 701, and if the line number is greater than 160, the process returns to step 501 (operation in the video end line identification unit 4). In the last step 701, the difference between the video start line number and the video end line number is obtained, and the difference is taken as the number of video lines (operation in the video line number calculation unit 5).

Steps 101 to 701 are repeated several times (this repetition will be described later) to obtain a stable number of video lines. When the number of video lines of the video signal of the Vista size shown in FIG. 2 is calculated by the above method, the video start line number is 50 and the video end line number is 210 (the line number is 10 as shown in FIG. 3). Since each line is included), the number of video lines is 160.

Next, a method of controlling the switching of the image display size will be described with reference to FIG. First, in step a, as the initial setting, the number of video lines is set to 260 (set by the video line number calculation unit 5). Next, the number of video lines is obtained by the above method (step b). Then, the number of image lines obtained this time is compared with the number of image lines obtained last time, and if they are equal, the counter is incremented by 1 (steps c and d) and the process proceeds to step g. Is retained as the detected value of (1) and the counter is reset (steps c, e, f), and the process returns to step a. Steps c to f are operations in the video mode identification unit 6.

In step g, while the counter value is less than 5 (if the number of video lines does not remain the same for a certain period of time), the operation is returned to step a and the counter value becomes 5 or more. If so, the operation proceeds to the next step h.
Steps g and h are also operations in the video mode identification unit 6.
In step h, in order to identify the video mode of the input video signal, the number of video lines obtained up to the previous stage is compared with the preset number of Vista size lines, and the obtained number of video lines is the Vista size. If it is larger than the number of lines,
The video mode of the input video signal is identified as a video mode with an aspect ratio of 4: 3, and the operation proceeds to step i. On the contrary, if the calculated number of video lines is equal to or smaller than the number of Vista size lines, the video mode of the input video signal is identified as the video mode of Vista size, and the operation proceeds to step j.

In step i, the deflection of the CRT with the aspect ratio of 16: 9 is controlled so that the signal in the image mode with the aspect ratio of 4: 3 has the optimum image display size on the CRT. In the step j, the deflection of the CRT is controlled so that the Vista size signal has the optimum image display size on the CRT. Steps i and j are operations in the video display size switching unit 7.
In this way, the present embodiment can automatically control the switching of the image display size.

In order to deal with a wider variety of video modes, it is possible to set a larger number of comparison lines in step h so that more video modes can be identified. Alternatively, the maximum brightness value may be detected for each line to more accurately calculate the number of video lines.

[0021]

As described above, the video display size automatic switching circuit according to the present invention changes the video display size according to the video mode of the input signal.
The video display size can be automatically switched to the optimum size.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an embodiment.

FIG. 2 is a diagram showing a display example of a Vista-size video signal.

FIG. 3 is a diagram showing a relationship between a line number and a maximum luminance value in a Vista-size video signal.

FIG. 4 is a flowchart showing a method for calculating the number of video lines.

FIG. 5 is a flowchart showing a switching control method of a video display size.

[Explanation of symbols]

 1 line number designation section 2 maximum brightness detection section 3 video start line identification section (line identification section) 4 video end line identification section (line identification section) 5 video line number calculation section 6 video mode identification section 7 video display size switching section

Claims (1)

[Claims] 1. A line designating a line number of a video signal input.
And the maximum brightness value within one line of the specified line number.
Compare the maximum luminance value detection section that detects sequentially and the maximum luminance value of the detected previous line and current line.
When the difference is more than a predetermined threshold, the video start try
Line identification section for distinguishing between the video end line and the video end line, the line number of the video start line and the video end line
Calculate the number of video lines from the difference between the line numbers
A video line number calculation unit, and a video mode of the video signal input based on the video line number.
The image mode identification section for identifying and the image table on the display section according to the identified image mode.
Video display that automatically switches the display size to a specified size
Video display server characterized by being composed of a size switching unit
Automatic switching device.