JPH07281626A - Interlace display device - Google Patents

Abstract

PURPOSE:To provide an interlace display device without flickering even when a thin line is displayed by using an interlace CRT 13. CONSTITUTION:This device is provided with a comparison arithmetic means 19 for reading three pixels from an image frame memory 11, one on a current scanning line specified by a field address counter 14, one on a vertical scanning line adjacent but one to the specified current scanning line pixel on a screen and one on a vertical scanning line adjacent but two thereto on the screen, and comparing a difference in luminance among these pixels and a switch means 20 for outputting, based on the calculation result of the comparison arithmetic means 19, the pixel on the vertical scanning line adjacent but one to the specified current scanning line pixel on the screen as a selected pixel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlaced display device which prevents screen flicker.

[0002]

2. Description of the Related Art In recent years, with the spread of multimedia technology, there has been a demand for displaying facsimile data and a computer display screen even on a conventional television (generally an interlaced display device) that displays only video images. .

FIG. 4 is a block diagram of a conventional interlaced display device. In the figure, an interlaced display device includes an interlaced display unit 9 and a control unit 10 which is responsible for overall control.
The details of the interlaced display section 9 are as follows.

Reference numeral 1 is an image frame memory, 2 is a D / A converter, 3 is an interlaced CRT, 4 is a field address counter for counting dot clocks and outputting the image position on the screen, and 5 is also for vertical scanning of the screen. , A vertical address counter for outputting the image position of 6, a horizontal address counter for outputting the image position on the horizontal scanning of the screen in the same manner, and 7 for generating a synchronizing signal for generating a synchronizing signal according to three kinds of addresses of field, vertical and horizontal Means, 8 is an oscillator for outputting a dot clock corresponding to a display dot on the screen.

The pixel signal output from the image frame memory 1 is converted into an analog signal by the D / A converter 2 and is supplied to the interlaced CRT 3 as a video signal in synchronization with the synchronization signal output from the synchronization signal generating means 7. The screen is displayed. In the interlaced CRT 3, the horizontal scanning line alternately scans an odd field displaying an odd-numbered raster and an even field displaying an even-numbered raster to smoothly display a video image.

[0006]

However, in such a conventional interlaced display device, when a thin line or a dot corresponding to one scanning line is displayed on the interlaced CRT 3 in the direction of the scanning line, an odd number or an even number is displayed. Since it is displayed only in one of the fields, it becomes flickering to the human eye, and there is a problem that the image display is very difficult to see.

An object of the present invention is to solve the above problems and to provide an interlaced display device which does not flicker even when fine lines are displayed using an interlaced CRT.

[0008]

In order to achieve the above object, the present invention relates to a pixel on a current scanning line designated by a field address counter from an image frame memory and a pixel on the designated current scanning line. Three pixels are read out, one on the vertical scanning line next to the screen and one on the vertical scanning line two next to the specified pixel on the current scanning line, and the brightness of these three pixels is read. And a switch for outputting a pixel on a vertical scanning line next to the designated pixel on the current scanning line as a selected pixel based on the calculation result of the comparison calculating unit. And means.

[0009]

With this configuration, if there is a difference in brightness above a certain level, the selected pixel is displayed by replacing it with the pixel on the specified current scanning line, so even if dots or thin lines are displayed using the interlaced CRT, flicker occurs. Can be displayed without.

In comparison with the brightness of the pixel of the adjacent scanning line, if the scanning line in the past direction is selected with respect to the current scanning line, the scanning line in the future direction with respect to the moving image or the current scanning line is selected. If is selected, it can be effectively applied to each still image.

[0011]

【Example】

(Embodiment 1) FIG. 1 is a block diagram of an interlaced display device according to a first embodiment of the present invention. In the figure,
The interlaced display device is composed of an interlaced display unit 9a and a control unit 10 which is responsible for overall control. The details of the interlaced display unit 9a are as follows.

Reference numeral 11 is an image frame memory, and 12 is a D / A.
A converter, 13 is an interlaced CRT, 14 is a field address counter that counts a dot clock and outputs an image position on the screen, 15 is a vertical address counter that similarly outputs an image position on a vertical scan of the screen, and 16 is the same. A horizontal address counter for outputting the image position on the horizontal scanning of the screen, 17 is a synchronizing signal generating means for generating a synchronizing signal in accordance with three kinds of addresses of field, vertical and horizontal, and 18 is a dot clock corresponding to a display dot on the screen. , 19 is a comparison calculation means for comparing and calculating the difference in luminance of pixels, and 20 is a pixel on the vertical scanning line next to the specified pixel on the current scanning line as a selected pixel. Switch means for

FIG. 2 is a diagram showing pixels on the CRT screen of the interlaced display device according to the first embodiment of the present invention. In the figure, 21 is a field address counter 1
The pixel designated by 4, 22 is the first adjacent pixel on the scanning line adjacent to the pixel 21 by one, and 23 is the second adjacent pixel on the scanning line adjacent by two above the pixel 21, and 24 is the odd field. Scanning lines, 25 are scanning lines of even fields.

Explaining in time series, only one scanning line is scanned in the past in the pixel 21 of the scanning line currently being displayed and the scanning line 24 of the same odd field as the present, and the pixel 21 is scanned. On the other hand, the second adjacent pixel 23, which is the next upper scanning line, and the first adjacent pixel, which is the scanning line 25 of the even field one field past and which is the next upper scanning line with respect to the pixel 21. 22 and 22.

The operation of the interlaced display device configured as described above will be described. First, the oscillator 18
Outputs a dot clock for display of the interlaced CRT 13. Based on this dot clock, the field address counter 14 outputs the field address of the display screen, the vertical address counter 15 outputs the vertical address of the display screen, and the horizontal address counter 16 outputs the horizontal address. The image frame memory 11 has the pixel 21 on the current scan line designated by the field address, vertical address, and horizontal address, for example, the scan line 24 of the odd field, and the pixel one above the pixel 21 on the screen. Next even field scan line 25
The first adjacent pixel 22 on the upper side and the second adjacent pixel 23 on the scanning line 24 of the odd field two adjacent to the upper side on the screen with respect to the pixel 21 are output.

Now, the brightness of the pixel 21 is X ₀ , the brightness of the first adjacent pixel 22 is X ₁ , and the brightness of the second adjacent pixel 23 is X.
_2. Let Y be the threshold value for determining the difference in brightness. As represented by (Equation 1), with respect to the luminance X ₁ of the first adjacent pixel 22 is a brightness X ₀ of the pixel 21 the average value of the luminance X ₂ of the second neighboring pixel 23, the luminance exceeds the threshold Y If there is a difference, first
Determines that the adjacent pixel 22 is a representation of a point or line, to display in brightness X ₁ substituting luminance X ₀ of the pixel 21 to the brightness X ₁ of the first adjacent pixel 22.

[0017]

[Equation 1]

Further, as expressed by (Equation 2), the first
Relative intensity X ₁ adjacent pixels 22 with the brightness X ₀ of the pixel 21 the average value of the luminance X ₂ of the second neighboring pixel 23, if there is only a difference in brightness is less than the threshold value Y, the first adjacent pixel 22 It is determined that the pixel or line is not expressed, and the luminance X _{0 of the} pixel 21 is displayed with the original luminance X ₀ .

[0019]

[Equation 2]

In this way, the comparison calculation means 19 (Equation 1)
The comparison calculation result calculated based on (Equation 2) is output to the switch unit 20. Switch means 20 outputs the luminance X ₀ of the pixel 21 as the selected pixel by replacing the luminance X ₁ of the first adjacent pixel 22, comparison operation result is less than the threshold Y when the comparison operation result exceeds the threshold value Y If the pixel 2
The brightness X ₀ of 1 is output as the selected pixel while maintaining the original brightness X ₀ .

Next, the selected pixel output from the switch means 20 is converted into an analog signal by the D / A converter 12, and is supplied to the interlaced CRT 13 as a video signal in synchronization with the sync signal output from the sync signal generation means 17. Is displayed. Therefore, in the interlaced CRT 13 for displaying the screen of the present embodiment, the horizontal scanning line alternately scans an odd field for displaying an odd numbered raster and an even field for displaying an even numbered raster, and a pixel of a dot or a thin line is used. Even if there is, the display is performed in the odd field and the even field, so that the display without flicker can be performed.

According to the first embodiment of the present invention, the judgment criterion of the selected pixel is obtained by the past first adjacent pixel 22 and second adjacent pixel 23 with respect to the pixel 21, so that a moving image is displayed. Can be effectively applied to.

(Embodiment 2) FIG. 3 is a diagram showing pixels on a CRT screen of an interlaced display device according to a second embodiment of the present invention. In the figure, 21 is the pixel specified by the field address counter 14, and 22 is the pixel 2
1 is the first adjacent pixel on the scan line adjacent to the pixel one below, 23 is the second adjacent pixel on the scan line adjacent two below the pixel 21, 24 is the scan line of the odd field, and 25 is the scan line of the even field. is there.

Further, in terms of time series, only one scan line is scanned in the future in the pixel 21 of the scan line currently being displayed and the scan line 24 of the same odd field as the present, and the pixel 21 is scanned in the future. On the other hand, the second adjacent pixel 23, which is the next adjacent scanning line two below, and the first adjacent pixel, which is the next adjacent scanning line to the pixel 21 by scanning with the scanning line 25 of the even field in the future by one field. 22 and 22.

The operation of the interlaced display device constructed as described above is explained in FIG. 2 (Example 1).
Since it is the same as the case of 1, the duplicate description will be omitted.

According to the second embodiment of the present invention, the still image is displayed because the determination criterion of the selected pixel is found in the future first adjacent pixel 22 and second adjacent pixel 23 with respect to the pixel 21. It can be effectively applied in cases.

[0027]

According to the interlaced display device of the present invention, a pixel on the current scanning line designated by the field address counter from the image frame memory and a vertical pixel adjacent to the pixel on the designated current scanning line by one on the screen. A comparison operation of reading out three pixels of a pixel on a scanning line and a pixel on a vertical scanning line two adjacent to the pixel on the designated current scanning line, and comparing and calculating a difference in luminance of these three pixels. Means and
Switch means for outputting, as a selected pixel, a pixel on the vertical scanning line next to the designated pixel on the current scanning line based on the calculation result of the comparison calculation means.

With this configuration, if there is a difference in brightness above a certain level, the selected pixel is displayed by replacing it with the pixel on the designated current scanning line, so that even if dots or thin lines are displayed using the interlaced CRT, flicker occurs. Can be displayed without.

In comparison with the brightness of the pixel of the adjacent scanning line, if the scanning line in the past direction is selected with respect to the current scanning line, the scanning line in the future direction with respect to the moving image or the current scanning line is selected. If is selected, it can be effectively applied to each still image.

[Brief description of drawings]

FIG. 1 is a block diagram of an interlaced display device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing pixels on a CRT screen of the interlaced display device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing pixels on a CRT screen of an interlaced display device according to a second embodiment of the present invention.

FIG. 4 is a block diagram of a conventional interlaced display device.

[Explanation of symbols]

 1, 11 Image frame memory 2, 12 D / A converter 3, 13 Interlaced CRT 4, 14 Field address counter 5, 15 Vertical address counter 6, 16 Horizontal address counter 7, 17 Sync signal generating means 8, 18 Oscillator 9, 9a Interlaced display unit 10 Control unit 19 Comparison calculation unit 20 Switch unit 21 Pixel 22 First adjacent pixel 23 Second adjacent pixel 24 Scanning line of odd field 25 Scanning line of even field

Claims (3)

[Claims] 1. An image frame memory for storing image data to be displayed on a display screen, a D / A converter for D / A converting the image data in synchronization with horizontal and vertical synchronizing signals of the display screen, and an odd number. An interlaced display unit having an interlaced CRT for alternately displaying an odd field displayed on the screen with the th horizontal scanning line and an even field displayed on the screen with the even horizontal scanning line; and an interlaced display control for the interlaced display unit. An interlaced display device including: a control unit for controlling a pixel on a scan line which is currently displayed from the image frame memory, and a first adjacent scan line on a screen adjacent to the pixel. Data of three pixels, that is, a pixel and a second adjacent pixel on a scanning line two adjacent to the pixel on the screen are read out, When the difference between the data of the pixel and the data of the second adjacent pixel with respect to the average value of the data of the first adjacent pixel exceeds a predetermined threshold value, it is determined that the first adjacent pixel is a point or line expression. An interlaced display device, comprising: an interlaced display unit, comprising: a comparison calculation means; and a switch means for replacing the data of the pixel with the data of the first adjacent pixel and outputting the data based on the judgment of the comparison calculation means. 2. The second adjacent pixel is a pixel of a scanning line which is scanned by one scanning line in the past in the same field as the pixel and which is located on the upper side by two on the screen with respect to the pixel. 2. The first adjacent pixel is a pixel of a scanning line which is scanned one field past the pixel and is located one level above and adjacent to the pixel on the screen. Interlaced display device. 3. The second adjacent pixel is a pixel of a scanning line which is scanned by one scanning line in the future in the same field as the pixel and which is located two adjacent lines below the pixel on the screen. , The first adjacent pixel is 1 with respect to the pixel
2. The interlaced display device according to claim 1, wherein a pixel of a scanning line which is scanned in the future in the field and is located one lower on the screen next to the pixel concerned.