JPH0724858Y2 - Fricker removal device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is an image forming an interlaced scanning video signal of a composite image in which a background image of a character pattern is superposed on a character pattern. The present invention relates to a flickering removing device which is provided in a processing device and reduces flickers in a vertical direction of a portion where a font pattern is inserted based on a brightness difference between a background image and a font pattern when the video signal is reproduced on a screen.

[Conventional technology]

Conventionally, image processing devices such as the superimposing device of the TVR often use digital image processing that uses a frame memory or the like to collect characters and symbols such as characters and symbols formed on a background image data by a character generator. The image data of the font pattern is superimposed, and the image data of the composite image of the frame structure is formed.

Further, the image data of the composite image is converted into an analog signal to form a video signal of interlaced scanning, and this video signal is supplied to a CRT or the like for a monitor to reproduce the screen of the composite image.

On the other hand, an image file device equipped with a large-capacity image storage medium such as an optical disk, a computer, etc. supplies a high-quality still image interlaced scan video signal to a CRT for a monitor, and a screen for editing or searching. It is supposed to play.

Also in the image file device, it is desired that the image processing device superimposes an image of a character font pattern such as an explanatory note on a background image having a still image structure and reproduces the image on the screen.

By the way, when a video signal of interlaced scanning is reproduced on a screen by a CRT, for example, as shown in FIG. 4, a frame image in which high-luminance scanning lines (h) and low-luminance scanning lines (l) alternately appear , The field screen of only the scanning line (h) and the field screen of the scanning line (l) are displayed alternately, so that a vertical flickering occurs on the screen.

Even when the video signal of the composite screen is reproduced on the screen, when the difference between the brightness of the background image and the brightness of the font pattern such as superimposed characters and symbols is large and the font pitch is narrow, the image of the font pattern is narrowed. Vertical flickering occurs in the font area where data is inserted.

When this flitska background image is a still image composition, it is easily noticeable,
In particular, when performing a superimpose with the image file device or the like, the flickers become extremely noticeable because the background image is a high-quality still image.

And, in the special table Sho 62-501464 (H04N 5/445),
When superimposing a character pattern on a background image of a television signal and displaying it on the screen by interlaced scanning, the line scanning is shifted by one line at the boundary between the inside and the outside of the font area to reduce the flickering. A removal device is described.

[Problems to be solved by the device]

In the case of the conventional flickering device, in the font area,
Since line scanning is only shifted at the outer boundary, it is not possible to reduce the flickering due to the brightness difference between the background pixel and the font pattern pixel in the font area, and moreover, the brightness of the background image and the font pattern. Therefore, the flickering is newly generated by shifting the line scanning.

Therefore, the flickers based on the brightness difference between the background image and the font pattern cannot be satisfactorily reduced, and particularly when a high-quality still image is used as the background image, high-quality screen reproduction cannot be performed. There is a point.

It is an object of the present invention to provide a flicker removing device that satisfactorily reduces the flicker.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the flickering removing device of the present invention includes background pixels of a font area in which the font pattern is inserted in a composite image having a frame structure formed by superimposing a character font pattern on the background image. In-area brightness correction means for correcting the brightness of the image data according to the brightness around each background pixel inside the font area, and image data of each background pixel in the vicinity of the font pattern outside the font area. And an out-of-area luminance correction unit that corrects the luminance so that the closer the vertical distance to the font pattern is, the closer it becomes to the luminance of the font pattern.

[Action]

In the case of the flickering removing apparatus of the present invention configured as described above, the in-area brightness correction means corrects the brightness of each background pixel in the vicinity of the font pattern in the font area so as to approach the brightness of the font pattern. .

In addition, the outside-area brightness correction unit corrects the brightness of each background pixel near the font pattern outside the font area so that the brightness becomes closer to the brightness of the font pattern as the scanning line becomes closer to the font area.

Therefore, when the luminance of the font pattern is high in the composite image of the frame structure corrected by both the correction means, the luminance of the background image portion in the font area and the boundary portion approaches the luminance of the font pattern.

Therefore, in the case of the font area portion of the composite image before correction, for example, as shown in FIG. 4, when the scan line (h) of the font pattern and the scan line (l) of the background image occur alternately, The luminance of the scanning line (l) of the image is increased and the luminance difference between the scanning lines (h) and (l) is reduced, and the inside of the font area when the image signal of the interlaced scanning of the composite image is reproduced on the screen and Vertical flicker at the boundary is reduced.

〔Example〕

One embodiment will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows a case where the present invention is applied to an image processing device provided in an image file device. In FIG. 1, (1) is an image capturing device such as an image scanner, and (2) is image data of a frame structure of a background image. Holding background frame memory,
(3) is a frame memory, and (2) is an address generator for addressing.

(4) is a control device having a computer configuration, (5) is a charactor generator that generates image data of charactor font patterns, (6) is a frame memory for fonts that holds image data of charactor font patterns, (7) Is an address generator for addressing the frame memory (6).

(8) is a distance measuring circuit to which the address information of the address generators (3) and (7) is input, and (9) is an out-of-area processing circuit to which the measurement result of the measuring circuit (8) is input. Out-of-area luminance correction means is formed together with (8) and a mixing circuit described later.

(10) is a mixing circuit for synthesizing the image data of the frame memories (2) and (6), and (11) is an intra-area processing circuit to which the image data of the composite image of the frame configuration of the mixing circuit (10) is input. , Forming an in-area luminance correction means.

(12) has a frame memory for buffer at the input stage
D / A converter circuit that outputs interlaced scanning video signals. (13) is a CRT for screen display.

The distance measuring circuit (8), both correction processing circuits (9),
(11) is formed by using, for example, a micro computer.

Then, the image data of each pixel of the background image having the high-quality still image structure captured by the image capturing device (1) is supplied to the background frame memory (2) together with the address information, and is stored in the memory (2). The image data of the background image is written and held.

In addition, the superimposing operation using a keyboard or the like supplies the code information of the charactor font pattern and the address information of the insertion position to the charactor generator (5) from the control device (4).

The charactor generator (5) supplies the image data of each pixel of the font pattern and the address information of the insertion position to the font frame memory (6), and the memory (6) receives the image of the font pattern for superimposing. Data is written and retained.

At this time, the font pattern is, for example, 16 × per character.
It consists of 16 pixels, and pixels such as characters and symbols (hereinafter referred to as font pixels) are set to high brightness (white).

Furthermore, the address generators (3) and (7) operate in synchronization under the control of the control device (4), and the address information of both address generators (3) and (7) causes both frame memories (2 ), (6) are read out to the repeating mixing circuit (10) in the order of the scanning lines of the frame screen.

Then, the image data of the combined image having a frame structure in which the character font pattern is superimposed on the background image is formed by the combination of the mixing circuit (10).

In the part of the font area in which the character font pattern of this composite image is inserted, characters and symbols are formed by high-intensity font pixels by superimposing the background image and the font pattern, and the surrounding area is surrounded by pixels of the background image. , That is, formed of background pixels.

Then, when the brightness correction described later is not performed, especially when the font pitch is narrow and the background pixel has low brightness (black), when the image signal of interlaced scanning is converted and the screen is reproduced, the vertical direction based on the brightness difference is displayed. Flickering occurs.

Therefore, the distance measurement circuit (8) and the out-of-area correction processing circuit (9) perform luminance correction outside the font area, and the in-area correction processing circuit (11) performs luminance correction inside the font area.

First, the brightness correction outside the font area will be described.

The address information of the address generators (3) and (7) is input to the distance measuring circuit (8), and by this measuring circuit (8),
Based on the address information of the address generator (3), the current pixel of the current scan line being inputted to the mixing circuit (10) is discriminated, and based on the address information of the address generator (7), the upper and lower ends of the font area are detected. Scan line (hereinafter referred to as end line)
And the positions of the font pixels of the end line are determined.

Further, it is determined whether or not the current pixel is the pixel at the same horizontal position as the font pixel of the end line, and whether the current scan line is outside the font area based on the comparison between the current scan line and the end line. Whether or not it is an outer line, the difference between the current scan line and the end line is calculated as the vertical distance from the current scan line to the font area.

Then, the determination result and the calculated value of the vertical distance are supplied from the distance measuring circuit (8) to the out-of-area correction processing circuit (9).

Since the correction processing circuit (9) corrects the brightness of the boundary portion between the font area and the outside thereof so as to prevent flickering, it operates when the vertical distance becomes equal to or less than the limit distance V of about several lines.

At this time, based on the quadratic curve-shaped luminance calibration characteristic of FIG. 2 set in the internal out-of-area luminance table memory, the correction processing circuit (9) only detects pixels at the same horizontal position as the font pixels of the end line. , And supplies luminance data corresponding to the vertical distance to the mixing circuit (10).

Then, by the data replacement of the mixing circuit (10), for each background pixel of the boundary portion, the brightness of the image data of the pixel at the same horizontal position as the font pixel of the end line becomes the brightness data of the correction processing circuit (9). Converted to luminance.

Due to this data replacement, the composite image of the frame configuration output from the mixing circuit (10) is such that the closer the vertical pixel distance to the font pixel is to the brightness of the background pixels above and below the boundary pixel, the closer the font pixel is to the pixel pixels. Is corrected to approach the high brightness of.

The output of the brightness data based on the processing time of the distance measuring circuit (8) and the correction processing circuit (9) is delayed by one frame from the output of the brightness data of the correction processing circuit (9).
Alternatively, a frame memory for buffer is provided at the output stage of the mixing circuit (10) for correction.

Then, the image data of the composite screen of the frame structure output from the mixing circuit (10) is input to the in-area correction processing circuit (11), and this processing circuit (11) corrects the brightness in the font area described below. Is applied.

That is, the correction processing circuit (11) temporarily holds the image data output from the mixing circuit (10) in the buffer frame memory.

Further, the background pixels of each scanning line inside the font area are sequentially detected based on the scanning line of the image data output from the mixing circuit (10) and the address information of the address generator (7).

Then, assuming that the detected background pixel is the target pixel (P ₀ ) in FIG. 3, for example, 3 × 3 pixels (P ₀ ), (P ₁ ), (P ₁ ), and (P ₁ ), inside the font area centered on this pixel (P ₀ ), ..., in (P _8), the luminance of the pixels surrounding the pixel of _{(P 0) (P 1)} ~ (P 8) is read.

At this time, based on the ratio between the number of high-intensity (= “1”) font pixels in the shaded area and the number of low-intensity (= “0”) background pixels in the non-diagonal area in FIG. The brightness of the image data of this pixel (P ₀ ) is corrected so that the brightness of the target pixel (P ₀ ) becomes higher as the number of pixels increases.

Therefore, the brightness of each background pixel inside the font area is corrected so as to approach the brightness of the font pixel particularly at the edge portion of the font pattern.

Then, the image data of the combined image corrected by the correction processing circuit (11) is supplied to the D / A conversion circuit (12), and the conversion circuit (12) converts the input image data of the combined image for each field. The scan line is shifted by one and converted to analog,
An interlaced scan video signal is formed.

Further, the video signal of the A / D conversion circuit (12) is supplied to the CRT (13), and the composite image is displayed on the screen by interlaced scanning on the CRT (13).

At this time, even if the inside of the font area and the boundary portion are in a luminance state where flickering occurs as shown in FIG. 4, for example, the both luminance correction makes the low-luminance scanning line (l) of FIG. Corrected, the brightness difference between the fields in the front area is reduced, and the vertical flickering is reduced.

Further, in the above-mentioned embodiment, the invention is applied to the image processing apparatus provided in the image file apparatus, but it can be applied to the image processing apparatus of various video equipment which performs the superimposing processing and outputs the interlaced scanning video signal. Of course you can.

When the font pixel has a low brightness (black), the brightness calibration characteristics shown in FIG.

The configurations of the in-area brightness correction means, the out-of-area brightness correction means, etc. are not limited to the embodiments.

[Effect of device]

Since the present invention is configured as described above, it has the following effects.

The in-area brightness correction unit corrects the brightness of each background pixel in the font area of the composite image of the frame structure so that the brightness of the background pattern is closer to the font pattern such as the edge portion of the font pattern.

Further, with respect to the boundary portion outside the font area, the outside-area brightness correction unit corrects the brightness of each background pixel in the vicinity of the font pattern so as to approach the brightness of the font pattern.

Then, an interlaced scanning video signal is formed based on the image data of the combined image corrected by both correction means.

Therefore, the brightness difference between the font pattern inside and inside the font area and the background image is reduced, and the vertical flickering at the time of screen reproduction of the interlaced scanning video signal based on this brightness difference can be sufficiently reduced. In particular, when a high-quality still image is used as the background image, it is possible to perform screen reproduction of a good composite image without flickering.

[Brief description of drawings]

1 to 3 show an embodiment of the flickering removing device of the present invention. FIG. 1 is a block diagram, FIGS. 2 and 3 are explanatory diagrams of brightness correction processing, and FIG. 4 is a flickering device. FIG. (1) ... Image capture device, (2) ... Background frame memory, (3), (7) ... Address generator, (4) ...
… Control device, (5) …… Character generator, (6) ……
Frame memory for fonts, (8) ... distance measuring circuit,
(9) …… Outside area correction processing circuit, (10) …… Mixing circuit, (11) …… Inside area correction processing circuit, (12) …… D / A
Conversion circuit, (13) …… CRT.

Claims (1)

[Scope of utility model registration request] 1. Image data of a background image and image data of a character pattern for superimposing are combined to form image data of a composite image having a frame structure in which the background pattern is superimposed on the background image. Then, in the anti-flicker device of the image processing device for converting the image data of the composite image into an analog signal to form a video signal of interlaced scanning, an image of each background pixel of the font area in which the font pattern of the composite image is inserted. In-area brightness correction means for correcting the brightness of the data in accordance with the brightness around each of the background pixels inside the font area, and the brightness of the image data of each background pixel near the font pattern outside the font area The closer the vertical distance to the font pattern is, the closer the brightness of the font pattern is. Flicker removing device provided with an area outside luminance correcting means for correcting.