JP5221397B2 - Impose character color automatic selection device - Google Patents

Description

The present invention relates to a superimpose display device that superimposes characters on video information when transmitting and reproducing video information captured by a still camera, a video camera, or the like.

Superimpose is a video effect that superimposes characters and figures on a video, and is also called a telop (television opaque projector). In television broadcasting, time announcements, weather forecasts, lyrics display in song programs, etc. This technology has been used for a long time. Hereinafter, superimposing characters on a video is referred to as “impose”.

Currently, the color of the characters to be imposed is often fixed to white, but with this method, for example, when there is a cloud or white building in the background, or when there is strong sunlight, the character can be distinguished from the background. It becomes unintentional, and the reading by the viewer is significantly hindered.

For example, in the case of fixed point monitoring for disaster prevention, even if the subject to be photographed is the same for a long time, the brightness of the image changes greatly between day and night when monitoring for 24 hours. It would be ideal to impose black letters or white letters at night.

In the early days of television broadcasting, a white or black card called an opec card was used to display black characters for white opec cards and white characters for black opec cards to make it easier to read.

On the other hand, as disclosed in Patent Document 1, for example, a means has been proposed for changing the character color to be imposed on the video information recorded on the recording medium according to the background color of the video information read from the recording medium. This is to determine the optimal character color by extracting the color information of the area where the character information is superimposed and calculating the average value of the saturation and hue between one frame.

Patent Document 2 also proposes means for changing the character color to be imposed by the contrast of the background color with respect to the display method of video and characters in the liquid crystal finder portion of the camera with a liquid crystal finder.

JP-A-8-195968 JP-A-10-319488

In general, in the case of an image transmission apparatus, the character imposing process to be mounted must be real-time, and is therefore often realized by hardware. However, when the character color is determined based on the average value of the background colors as described above, the color information for each pixel dot on the screen must be added and then divided by the number of pixels when calculating the background color. Rather, the calculation is complicated because of the increase in the number of bits due to the addition and the change in the divisor of the division.

In addition, the number of pixels tends to increase due to the development of electronic devices and communication technologies, and the increase in the amount of computation accompanying this is also a major barrier.

In addition, since video information changes from moment to moment, frequent changes in text color due to changes in video are painful for viewers, making it easier to read and preventing smooth viewing. It can also be a thing. Therefore, a protection function for preventing so-called chattering that the impose character color frequently changes is essential.

As described above, in order to solve the problem of low computational complexity and avoiding frequent character color changes, the following measures are taken in the present invention.

The present invention, for example, in a system for viewing moving image information captured by a camera or the like installed for monitoring a road or a river on a monitor via a network,
An impose area pixel reading unit that reads out pixel data of an area in which character impose is performed from video information data photographed by the photographing equipment;
A pixel lightness comparison unit that determines whether the lightness of the pixel read by the impose area pixel reading unit is higher or lower than the reference value A when the lightness value of the halftone is the reference value A;
A brightness integration unit that adds 1 to the white value W if it is determined that the pixel brightness comparison unit is high;
An integral value comparison unit that compares the white value W and the black value B as a result of the pixel brightness comparison unit comparing all the pixel data read by the impose region pixel reading unit;
A character color determining unit that determines the impose character color to be black when the integral value comparing unit determines that the white value W is high, and determines the impose character color to be white when it is determined that the black value B is high;
A character information generation unit that generates character information according to the character color determined by the character color determination unit;
The automatic character selection device for impose characters consisting of

By this means, the processing is not complicated, and the character can be imposed with a low calculation amount, and further, all procedures can be automated.

Further, according to the present invention, the processing unit of video information is called a frame, and the number of consecutive white frames W continuously determined by the integral value comparison unit as the white value W being large is the number of consecutive white frames X, and When the continuous number determined that the value B is large is the continuous black frame count Y, the continuous white frame count X threshold is the continuous white frame threshold M, and the continuous black frame count Y threshold is the continuous black frame threshold N,
The protection unit that receives the comparison result of the integral value comparison unit compares the continuous white frame count X with the continuous white frame threshold M, and determines that the continuous white frame count X is equal to or greater than the continuous white frame threshold M. The character color determining unit determines the impose character color to be black, compares the continuous black frame count Y with the continuous black frame threshold N, and determines that the continuous white frame count X is equal to or greater than the continuous black frame threshold N. In this case, the character color determination unit determines the impose character color to be white, and provides an impose character automatic color selection device.

This means can prevent so-called character color change chattering, in which the character color changes frequently.

Further, in the present invention, the character color is fixed to an arbitrary color, and when the character color determination unit determines the character color to be white, the border color of the character is set to white and the character color is determined to be black. In such a case, the automatic character selection device for the impose character is characterized in that the border color of the character is black.

By this means, even if the character color remains fixed, it is possible to help the viewer of the video information understand the separation of the background color and the character by changing the color of the edge of the character.

According to the present invention, since the character color to be imposed on the video information can be automatically determined, for example, an image captured by a photographing device that performs fixed point monitoring on a 24-hour basis, which requires changing the character color between day and night It is possible to simplify the work of changing the character color superimposed on the. Further, by adopting means that does not frequently change the character color, flickering of the screen can be prevented, and the viewer can easily view the video information and the character information.

Overall block diagram Processing flowchart Processing flow of protection unit Change in character color to be determined

A preferred embodiment relating to means for determining an impose character color while preventing chattering according to the present invention will be described with reference to the drawings.

FIG. 1 is an overall block diagram according to the present invention. From the video information data sequence photographed by the photographing equipment, the impose area pixel reading unit 101 reads the brightness data of each pixel in the area on the screen where the character is to be imposed. In the video information data sequence, a processing unit for one screen drawing on the screen is referred to as a frame.

Next, the pixel lightness comparison unit 103 determines whether the lightness value of the read pixel is higher or lower than the predetermined reference value A105. Based on the determination result, the lightness integration unit 107 increments the white value W109 or the black value B111 by one, and obtains the white value W and the black value B when the processing for all the pixels in the impose area is completed. The integrated value comparison unit 113 determines the size.

The magnitude relationship between the white value W and the black value B indicates whether there are many white parts or many black parts in the area where the character is to be imposed. If it is determined, the color of the imposed character is black, and if it is determined that the value of the black value B is large and the color of the imposed character is white, it is one means. There is a high possibility that the magnitude relationship of the black value B is frequently changed.

At that time, if the character color to be imposed is changed every time the integral value comparison unit 113 determines, flickering of the screen due to so-called chattering that the character color changes frequently occurs, and it is painful for the viewer to watch the video and characters. Can be a forcing. Therefore, the protection unit 115 implements means for minimizing the change of the character color to be imposed and preventing chattering.

A numerical value indicating how many frames the white value W is greater than the black value B continues for a number of consecutive white frames X, and a numerical value indicating how many frames the black value B is greater than the white value W continues for a continuous black The number of frames is Y, and the predetermined threshold values are a continuous white frame threshold value M and a continuous black frame threshold value N.

The protector 115 manages the increase and initialization of the continuous white frame count X and the continuous black frame count Y, compares the continuous white frame threshold M with the continuous black frame threshold N, and compares the continuous white frame count X with the continuous white frame threshold M. The magnitude relationship between the continuous black frame count Y and the continuous black frame threshold N is transmitted to the character color determination unit 125, and the character color to be imposed is determined. Next, the character information generation unit 127 generates a necessary character string with the determined character color.

Next, a more detailed processing flow will be described with reference to FIG.

A video is photographed with a photographing device such as a video camera (S201), and the brightness data of the pixel in the region where the character is imposed in the video information is read (S203). The data number of the read pixel is n, the counter that increases when the brightness of the pixel is greater than a predetermined reference value A is the white value W, the counter that increases when the pixel brightness is smaller is the black value B, and before the loop processing Variables n, W, and B are initialized (S205).

In the loop processing for sequentially verifying pixels, first, it is determined whether the brightness of the nth pixel is brighter or darker than a predetermined reference value A (S207). As a result, when it is determined that it is brighter than the reference value A, 1 is added to the white value W (S209). If it is determined that the image is darker than the reference value A, 1 is added to the black value B (S211). Thus, the value of the white value W is the number of pixels in the bright part in the character impose area, and the value of the black value B is the number of pixels in the dark part.

Next, 1 is added to the pixel number n (S213), and it is determined whether or not all the determinations for one frame have been completed for the pixels in the region to be character-imposed (S215). If it is not the last pixel, the process returns to the comparison process S207 with the reference value A again.

When the pixel processed immediately before is the last pixel number, a chattering protection process (S217) described later is performed.

The chattering protection process operates so as to prevent chattering in which the implied character color frequently changes, and as a result, the character color of the impose character is determined, and character information is generated with the character color (S219).

The generated character information is superimposed on the video information, and the process of imposing characters on the video is completed (S221). The video information on which the character is imposed is distributed to the viewer via a network or the like (S223).

Next, chattering protection processing (S217) including the protection unit 115 and the character color determination unit 125 will be described with reference to FIG.

A white value W and a black value B for one frame are input to the chattering protection processing unit. First, the magnitude determination of the white value W and the black value B is performed (S301). As a result, if the white value W is larger than the black value B, 1 is added to the number X of consecutive white frames, and the number Y of consecutive black frames is set to 0 (S303). If the black value B is larger than the white value W, 1 is added to the continuous black frame count Y, and the continuous white frame count X is set to 0 (S305).

If 1 is added to the number of consecutive white frames X, it is then determined whether or not the number of consecutive white frames X has reached the continuous white frame threshold M as a result (S307). If 1 is added to the continuous black frame count Y, it is then determined whether or not the continuous black frame count Y has reached the continuous black frame threshold N as a result (S309).

If the number of consecutive white frames X is equal to or greater than the continuous white frame threshold value M, it is determined that the state of high brightness of the video continues for a certain time or more, and the character color to be imposed is determined to be black (S311). If the continuous black frame count Y is equal to or greater than the continuous black frame threshold N, it is determined that the low brightness of the video continues for a certain time or more, and the imposed character color is determined to be white (S313). . If the continuous white frame threshold value M and the continuous black frame threshold value N have not been reached, the character color continues the state one frame before (S315).

FIG. 4 shows an example of how the implied character color actually changes when the chattering protection process is not performed and when it is performed.

In FIG. 4, the horizontal axis represents the number of video frames. As described above, in the video information data sequence, the processing unit for one screen of drawing is called a frame, and the horizontal axis moves to the right as the time changes.

The vertical axis represents the number of consecutive white frames X and the number of consecutive black frames Y at the end of processing for one frame, and the continuous white frame threshold M and the continuous black frame threshold N are shown in the graph. As described above, one of the continuous white frame count X and the continuous black frame count Y is incremented by 1 and one is initialized to 0. Therefore, the section in which one extends in the vertical axis direction is The other takes a value of zero.

First, a case where there is no chattering protection function will be described.

First, the state where the white value W at the end of the frame is larger than the black value B, that is, the state where the number of consecutive white frames X is increasing continues. In this state, since it is determined that the brightness of the image in the area to be imposed is high, the character color to be imposed is determined to be black if there is no chattering protection function. Since the magnitude relationship between the white value W and the black value B is reversed at the number of frames b and the black value B is determined to be larger than the white value W, the number of consecutive white frames X is set to 0, and the number of consecutive black frames Y is Start increasing. During this time, since it is determined that the brightness of the image in the area to be imposed is low, the character color to be imposed changes to white.

Further, at the frame number c, the white value W is again larger than the black value B, and the character color to be imposed changes to black. In this way, in the comparison between the white value W and the black value B, the character color to be imposed is all black for the section where the white value W is larger, and the character color to be imposed is all for the section where the black value B is larger. Decided to be white.

Next, a case where a chattering protection function is provided will be described.

The chattering protection function uses whether the number of consecutive white frames X has reached the continuous white frame threshold M or whether the number of consecutive black frames Y has reached the continuous black frame threshold N as a character color criterion. The character color in the previous frame is maintained up to the number of frames a, and the number of consecutive white frames X reaches the continuous white frame threshold value M in the number of frames a. Therefore, the character color is determined to be black here.

In the number of frames b, the black value B is larger than the white value W, and the number of continuous white frames is also 0. However, since the number of continuous black frames Y has not reached the continuous black frame threshold N, the character color does not change. . Since the continuous black frame number Y has reached the continuous black frame threshold N in the frame number e, the character color is changed to white here.

Similarly, although the white value W is larger than the black value B in the number of frames f, since the number of consecutive white frames X has not reached the continuous white frame threshold M, the character color is not changed.

As described above, in FIG. 4, when the change in the character color between the case without the protection function and the case with the protection function is compared, frequent character color change, that is, occurrence of chattering is suppressed by the effect of the protection function. I understand.

In this embodiment, the character color determining means for the character to be imposed and the chattering protection means for suppressing frequent character color changes have been described. In the present invention, regarding the reference value A, the continuous white frame threshold value M, and the continuous black frame threshold value N, there are no restrictions on the determination of the values.

In the present invention, the embodiment has been described by limiting the character color to white or black. However, the present invention is not limited to this. For example, the larger the value obtained by subtracting the black value Y from the white value X, the closer the character color is to white, and the larger the value obtained by subtracting the white value X from the black value Y is, the closer the character color is to black. A character color determining means using gray scale or color is also conceivable.

Although the present embodiment has been described in the present embodiment so as to change the character color itself as a means for making it easier for the viewer to view the video, the present invention is not limited to this. For example, according to the present invention, the character color is fixed and the color of the edge when the character is trimmed can be changed according to the present invention.

101 ... Impose area pixel reading unit, 103 ... Pixel brightness comparison unit,
105 ... reference value A, 107 ... lightness integration unit,
109 ... white value W, 111 ... black value B,
113 ... Integral value comparison unit, 115 ... Protection unit,
117: Continuous white frame count X, 119: Continuous black frame count Y,
121 ... Continuous white frame threshold M, 123 ... Continuous black frame threshold N,
125: Character color determining unit, 127: Character information generating unit,

Claims (3)

For example, in a system for viewing video information captured by a camera installed for monitoring roads and rivers on a monitor via a network,
An impose area pixel reading unit that reads out pixel data of an area in which character impose is performed from video information data photographed by the photographing equipment;
A pixel lightness comparison unit that determines whether the lightness of the pixel read by the impose area pixel reading unit is higher or lower than the reference value A when the lightness value of the halftone is the reference value A;
A brightness integration unit that adds 1 to the white value W if it is determined that the pixel brightness comparison unit is high;
An integral value comparison unit that compares the white value W and the black value B as a result of the pixel brightness comparison unit comparing all the pixel data read by the impose region pixel reading unit;
A character color determining unit that determines the impose character color to be black when the integral value comparing unit determines that the white value W is high, and determines the impose character color to be white when it is determined that the black value B is high;
A character information generation unit that generates character information according to the character color determined by the character color determination unit;
Impose character automatic color selection device consisting of The processing unit of the video information is called a frame, and the number of consecutive times in which the white value W is continuously determined to be large in the integral value comparison unit is determined to be the number of consecutive white frames X and the black value B is continuously large. When the number of consecutive black frames is the number Y of continuous black frames, the threshold of the number of consecutive white frames X is the continuous white frame threshold M, and the threshold of the number of consecutive black frames Y is the continuous black frame threshold N,
The protection unit that receives the comparison result of the integral value comparison unit compares the continuous white frame count X with the continuous white frame threshold M, and determines that the continuous white frame count X is equal to or greater than the continuous white frame threshold M. The character color determining unit determines the impose character color to be black, compares the continuous black frame count Y with the continuous black frame threshold N, and determines that the continuous white frame count X is equal to or greater than the continuous black frame threshold N. 2. The impose character automatic color selection apparatus according to claim 1, wherein the character color determination unit determines the impose character color to be white when the character color is determined. When the character color is fixed to an arbitrary color and the character color determining unit determines that the character color is white, the character border color is white, and when the character color is black, the character color is 3. The impose character automatic color selection device according to claim 1, wherein the border color is black.