JP4565903B2 - On-screen display device - Google Patents

Description

  The present invention relates to an on-screen display that superimposes and displays other images such as a telop, a caption, and a setting menu of a display device on a part of a main image displayed on a display device.

A technique called α blending is known as an on-screen display technique that superimposes and displays other images such as telops, subtitles, and display device setting menus on part of the main image displayed on the display device. Yes.
Hereinafter, for convenience of explanation, a main image displayed on the display device is referred to as a “base image”, and an image superimposed on a part of the base image is referred to as an “OSD image”.
The α blend is an image obtained by mixing an image portion in the arrangement area of the base image and the OSD image arranged in the arrangement area at a ratio of a: (1−a) in the arrangement area of the OSD image on the base image. By displaying, the OSD image is displayed on the base image as if the OSD image is translucent and the base image behind it is seen through. Also, with this α blending technology, the mixing ratio (transparency) with the base image can be controlled for each pixel of the OSD image by data called α channel layer data.

In addition, as a technology to which such α blending technology is applied, the luminance of the pixels of the base image in the OSD image arrangement area is reduced, thereby making the character portion displayed opaquely in the OSD image by the base image. A technique that suppresses the deterioration of visibility is known (for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-146275

In the above-described OSD image display technique using α blending, the mixing ratio of the OSD image and the base image can be freely controlled for each pixel, so that an on-screen display excellent in visibility and decoration can be performed.
However, according to this technology, in addition to the base image and the OSD image, it is necessary to perform processing that handles α channel layer data for controlling the transparency of each pixel of the OSD image. In some cases, the amount of processing for on-screen display may be excessive. In addition to the OSD image, it is also necessary to create α channel layer data in advance and supply it to a device that performs on-screen display together with the base image and the OSD image.

  Therefore, an object of the present invention is to realize an on-screen display excellent in visibility and decoration with a configuration that does not use data for controlling transparency for each pixel.

  In order to achieve the above object, the present invention provides an on-screen display device that superimposes and displays a sub-image on a part of a base image, and each pixel value of the sub-image includes a set pixel value that is a preset pixel value. Match detection means for detecting whether or not they match, and for each pixel of the sub-image, a mixing ratio of the pixel and the pixel of the base image is set to a pixel whose pixel value matches the set pixel value A mixture ratio setting means for setting the mixture ratio to be set to a different value for a pixel whose pixel value does not match the set pixel value, and each pixel of the sub-image is set to the pixel And a mixing unit that mixes and outputs the pixels of the base image at a mixing ratio. Hereinafter, the on-screen display device configured as described above is referred to as a first on-screen display device.

  Now, according to such a first on-screen display device, without using data for controlling the transparency for each pixel such as the α channel data of the α blend, the transparency of the pixel of the sub-image is determined for each pixel. It becomes possible to control according to the pixel value. Therefore, by using this, an on-screen display that is more excellent in visibility and decoration can be performed.

  More specifically, in such a first on-screen display device, for example, in the mixing ratio setting unit, the mixing ratio set to the pixel of the sub-image whose pixel value matches the set pixel value is It may be configured to set such that the mixing ratio of the pixels of the sub-image in the mixing unit is larger than the mixing ratio set to the pixels of the sub-image whose pixel value does not match the set pixel value. Good.

  And by doing in this way, for example, if the pixel value of the color used as the character color in the sub-image is set as the set pixel value, the characters in the sub-image are clearly displayed with relatively low transparency, About the background part of the character in a subimage, it can display as a relatively high transparency so that a base image can be seen through to some extent.

  The on-screen display device described above further includes a control device that selectively designates one of a plurality of transparent levels in the mixing ratio setting unit, and the setting pixel in the mixing ratio setting unit. A specified transparency level indicates a mixture ratio set for pixels of the sub-image whose values and pixel values match, and a mixture ratio set for pixels of the sub-image whose pixel values do not match the set pixel values. You may make it change so that the ratio of the pixel of the said subimage in the said mixing means may become large, so that it is small.

By doing in this way, it becomes possible to realize more diverse or flexible on-screen displays.
Alternatively, the above-described first on-screen display device is provided with a control device that selectively designates one of a plurality of transparency levels in the mixing ratio setting means, and the setting of the setting ratio in the mixing ratio setting means The mixing ratio set for the pixel of the sub-image whose pixel value matches the pixel value and the mixing ratio set for the pixel of the sub-image whose pixel value does not match the specified pixel value Is changed so that the mixing ratio of the pixels of the sub-image in the mixing unit increases, and the mixing ratio in which the mixing ratio of the pixels of the sub-image in the mixing unit is less than 100% is set to the mixing ratio. When the setting means specifies a transparency level that specifies that the set pixel value does not match the pixel value of the sub-image, the setting pixel value is set. The mixing ratio set in the pixel of the sub-image in which the pixel value matches the pixel value is higher than the mixing ratio set in the pixel of the sub-image in which the set pixel value does not match the pixel value. You may make it set so that the mixing ratio of the pixel of a subimage may become large.

  By doing in this way, the said control part can perform the fade-in display of the said sub image by reducing gradually the transparency level set to the said mixture ratio setting means at the time of the display start of the said sub image, for example. It becomes like this. Further, when the display of the sub-image is finished, the sub-image can be faded out by gradually increasing the transparency level set in the mixing ratio setting means.

  Further, the fade-in display and the fade-out display can be made excellent in decorativeness. That is, for example, if a pixel value of a color used as a character color in the sub-image is set as the set pixel value, the sub-image is clarified little by little in the form in which the character background portion is delayed with respect to the character manifestation. The fade-in display with excellent characteristics and the fade-out display with excellent decorativeness in which the sub-image is erased little by little in the form where the disappearance of the characters is delayed with respect to the disappearance of the background portion of the characters.

  As described above, according to the present invention, an on-screen display excellent in visibility and decorativeness can be realized by a configuration that does not use data for controlling transparency for each pixel.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows a configuration of an on-screen display device according to the present embodiment.
As illustrated, the on-screen display device includes an OSD display control unit 1, an OSD image generation unit 2, a blend control unit 3, a mixing processing unit 4, and a delay processing unit 5. The blend control unit 3 includes a character color register 31, a coincidence detection unit 32, and a transmittance control unit 33.

  In such a configuration, the OSD image generation unit 2 generates an OSD image having contents instructed by the OSD display control unit 1 and outputs an OSD image signal representing the OSD image. Here, a base image signal that is a video signal serving as a base image and a base image synchronization signal that is a horizontal / vertical synchronization signal of the base image signal are input to the on-screen display device from the outside. Then, the OSD image generation unit 2 is synchronized with a base image synchronization signal input from the outside at a timing at which a base image signal representing a portion of the base image in the OSD image arrangement area instructed from the OSD display control unit 1 is input. , Output an OSD image. The OSD image generation unit 2 outputs the OSD area signal to the mixing processing unit 4 while outputting the OSD image signal.

  Next, the mixing processing unit 4 inputs the base image signal and the OSD image signal, mixes the base image signal and the OSD image signal, and outputs it as a display image signal. The mixing processing unit 4 controls the mixing ratio of the base image signal and the OSD image signal as follows. That is, the mixing ratio of the base image signal and the OSD image signal during the period when the OSD area signal is not output from the OSD image generation unit 2 is 100% for the base image and 0% for the OSD image. The mixing ratio of the base image signal and the base image signal during the period when the OSD area signal is output from the OSD image generation unit 2 is a mixing ratio according to the transmittance control signal TP instructed from the blend control unit 3. .

Next, the delay processing unit 5 delays the base image synchronization signal by the processing delay in the mixing processing unit 4 and outputs it as a synchronizing signal of the display image signal output from the mixing processing unit 4.
Then, the blend control unit 3 sets the pixel value representing the color used as the character color in the OSD image, the blend level BL specified by the OSD display control unit 1, and the OSD set in the character color register 31 by the OSD display control unit 1. Using the OSD image signal output from the image generation unit 2, the mixing ratio of the OSD image signal and the base image signal in the mixing processing unit 4 is designated by the transmission ratio control signal TP for each pixel of the OSD image.

Here, the structural example of the mixing process part 4 is shown to FIG.
As shown in the figure, the mixing processing unit 4 can be configured by, for example, a mask control unit 41, a mask circuit 42, and an adder 43.
The mask circuit 42 includes an OSD image signal X0, a 1/2 OSD image signal X1 in which the pixel value of the OSD image signal is halved, a 1/4 OSD image signal X2 in which the pixel value of the OSD image signal is ¼, and OSD. A 1/8 OSD image signal X3 in which the pixel value of the image signal is 1/8 and a 1/16 OSD image signal X4 in which the pixel value of the OSD image signal is 1/16 are input. The mask circuit 42 also includes a base image signal Y0, a ½ base image signal Y1 in which the pixel value of the base image signal is halved, and a ¼ base image in which the pixel value of the base image signal is ¼. The signal Y2, the 1/8 base image signal Y3 in which the pixel value of the base image signal is 1/8, and the 1/16 base image signal Y4 in which the pixel value of the base image signal is 1/16 are input.

  Here, when the image signal is a digital signal, the division of each image signal by 2 to the power of n can be realized by bit-shifting the pixel data to the lower side by n bits. For example, division of pixel data by 2 can be realized if 8 bits are pixel data, 2-8 bits are 1-7 bits, and the eighth bit is 0.

Now, the mask circuit 42 has ten outputs D0 to D9 corresponding to each of the ten input signals X0 to X4 and Y0 to Y4, and each output has a corresponding input signal. One of the signals representing the pixel value 0 is selectively output according to the control of the mask control unit 41.
The ten output signals D0 to D9 output from the mask circuit 42 are added by the adder 43 and output as a display image signal.
According to such a configuration of the mask circuit 42 and the adder 43, as shown in FIG. 2b, OSD image pixel: base image pixel = 100%: 0% to OSD image pixel: base image pixel = 0%: 100%. Up to the above, it is possible to realize the mixing of the pixels of the base image and the pixels of the OSD image with the mixing ratio of 17 steps.

In FIG. 2 b, each row in the row range 200 of columns 201 to 205 and columns 206 to 210 represents a value output from the mask circuit 42 to the outputs D0 to D9 shown in the row 211. Indicates that a signal representing a pixel having a value of 0 is output.
Each row of the column 221 represents a mixing ratio of OSD image pixels realized by a combination of outputs of the row, and a column 222 represents a mixing ratio of base image pixels by a combination of outputs of the row.
Each row of the column 231 is a value of the transmittance control signal TP output by the blend control unit 3 in order to specify the mixing ratio of the OSD image pixel and the base image pixel, which is realized by a combination of the outputs of the row. Is shown.
Now, as described above, the mask control unit 41 masks the mixture ratio so that the OSD image pixel: base image pixel = 0%: 100% during the period when the OSD area signal is not output from the OSD image generation unit 2. The operation of the circuit 42 is controlled. That is, the mask circuit 42 is caused to perform the output indicated by the row 241 in FIG.

  On the other hand, the mask control unit 41 transmits the transmission ratio instructed from the blend control unit 3 according to the transmission ratio control signal TP instructed from the blend control unit 3 during the period when the OSD area signal is output from the OSD image generation unit 2. The mask circuit 42 is caused to perform the output shown in the row of FIG. 2b corresponding to the value (0 to 16) of the control signal TP.

  Returning to FIG. 1, the blend control unit 3 includes a pixel value representing a color used as a character color in the OSD image set by the OSD display control unit 1 in the character color register 31 and the OSD display control unit 1 Using the blend level BL to be specified and the OSD image signal output from the OSD image generation unit 2, the mixing ratio of the OSD image signal and the base image signal in the mixing processing unit 4 is determined for each pixel of the OSD image. Specify by. Here, the blend control unit 3 outputs a value from 0 to 16 as the blend level BL.

That is, the coincidence detection unit 32 compares the pixel value represented by the OSD image signal with the pixel value set in the character color register 31 and outputs the coincidence / mismatch to the transmittance control unit 33. The character color register 31 is configured so that the OSD display control unit 1 can set a plurality of pixel values for the plurality of pixel values. In the coincidence detection unit 32, the pixel value represented by the OSD image signal is the character color register 31. It is also possible to output coincidence to the transmittance control unit 33 when the pixel value matches any one of the plurality of pixel values set to, and mismatch in other cases. In this way, a plurality of character colors can be used in the OSD image.
Now, the transmittance control unit 33 receives the transmittance control signal TP output to the mixing processing unit 4 in accordance with the blend level BL input from the OSD display control unit 1 and the match / mismatch input from the match detection unit 32. It changes according to the table | surface shown in FIG.

That is, when the input from the coincidence detection unit 32 is inconsistent, the transmittance control unit 33, therefore, the OSD image pixel represented by the OSD image signal being output by the OSD image generation unit 2 is not a pixel constituting the character. In this case, the value of the blend level BL input from the OSD display control unit 1 is output as it is as the transmittance control signal TP.
On the other hand, when the input from the coincidence detection unit 32 is coincident, the transmittance control unit 33 is, therefore, the pixel of the OSD image represented by the OSD image signal being output by the OSD image generation unit 2 is a pixel constituting a character. In some cases, a value obtained by subtracting 8 from the value of the blend level BL input from the OSD display control unit 1 is output as the transmittance control signal TP. However, when the value obtained by subtracting 8 from the value of the blend level BL is smaller than the minimum value 0 of the transmittance control signal TP, 0 is output as the transmittance control signal TP.

  As a result, as shown in FIG. 3, the mixing ratio of pixels in the OSD image that do not constitute characters to the base image is controlled to 17 levels by the blend level BL. Further, the mixing ratio of the pixels constituting the character in the OSD image to the base image is controlled to be 50% larger than the pixels not constituting the character in the OSD image in a range not exceeding 100%.

The operation of the OSD display control unit 1 when performing on-screen display is, for example, as follows.
That is, the OSD display control unit 1 first sets a pixel value representing a color used as a character color in the OSD image to be displayed in the character color register 31 of the blend control unit 3, and outputs a value 4 as the blend level BL. To do. Then, the OSD image generation unit 2 is instructed about the contents of the OSD image to be generated and the OSD image arrangement area on the base image.

  As a result, the image represented by the display image signal output from the on-screen display device has an OSD image on the base image, and the non-character portion has a mixing ratio of the base image pixel and the OSD image pixel of 25%. : 75%, and the character portion is displayed with the mixing ratio of the base image pixel and the OSD image pixel being 0%: 100% (see the line of FIG. 3, blend level BL = 4).

Here, FIG. 4A shows an example of an image represented by the display image signal output from the on-screen display device.
As shown in the figure, in this image, an OSD image 41 is displayed on the base image 40. The character portion 411 of the OSD image 41 is clearly displayed opaque (mixing ratio of base image pixels and OSD image pixels = 0%: 100%), and the background portion 412 of characters other than the characters of the OSD image 41 is displayed. Is displayed in a translucent manner (the mixing ratio of the base image pixel and the OSD image pixel = 25%: 75%) so that the base image 40 below can be seen through.

  Here, FIG. 4B shows an image when the entire OSD image 41 is displayed on the base image 40 in an opaque manner (mixing ratio of the base image pixel and the OSD image pixel = 0%: 100%). As shown in the figure, in this case, the character portion 411 is clearly displayed with good visibility, but the base image 40 below the OSD image 41 cannot be visually recognized at all. On the other hand, FIG. 4C shows an image when the OSD image 41 is displayed on the base image 40 in a semi-transparent manner with the same mixing ratio (the mixing ratio of the base image pixel and the OSD image pixel is 25%: 75%). As shown in the figure, in this case, the entire base image 40 of the OSD image 41 can be seen through, but the visibility of the character 411 of the OSD image 41 is lower than that of the OSD image 41. The base image 41 is somewhat degraded.

  Now, the OSD display control unit 1 performs fade-in display in which the OSD image is displayed on the base image little by little after the start of the on-screen display, and when the on-screen display ends, the OSD image is gradually displayed from the base image. The fade-out display to be erased can also be controlled.

  That is, when performing fade-in display, OSD display control performs the following operations. That is, the OSD display control unit 1 first sets a pixel value representing a color used as a character color in the OSD image to be displayed in the character color register 31 of the blend control unit 3, and outputs a value 16 as the blend level BL. . Then, the OSD image generation unit 2 is instructed about the contents of the OSD image to be generated and the OSD image arrangement area on the base image. Thereafter, as indicated by an arrow 301 in FIG. 3, the blend level BL value is periodically decreased by 1 from 16 until the blend level BL value becomes 4.

  When performing fade-out display, OSD display control performs the following operations. That is, the OSD display control unit 1 periodically increases the value of the blend level BL from 4 to 1 until the value of the blend level BL reaches 16, as indicated by the arrow 302 in FIG. Then, the OSD image generation unit 2 finishes generating the OSD image.

  However, a normal on-screen display may be performed with the blend level BL value set to 0. In this case, in the fade-in display, the blend level BL value is changed from 16 and the blend level BL value is set to 0. Until it becomes, the value is decreased by 1 periodically, and in the fade-out display, the value of the blend level BL is periodically increased from 0 by 1 until the value of the blend level BL becomes 16. It may be.

5a and 5b show examples of display images with blend levels BL from 0 to 16. FIG.
In FIGS. A and b, C is an example of the display image according to the present embodiment, and A is the case where the same mixing ratio is applied to the character portion of the OSD image as the portion other than the character, that is, the coincidence detection unit. 32 is an example of a display image similar to the case where a mismatch is always detected, and B is a case where the mixing ratio of the base image pixel and the OSD image pixel in the character portion of the OSD image is fixed to 0%: 100%. It is an example of a display image.

  As understood from comparison with A and B in the figure, according to the fade-in display of the present embodiment, the OSD image is clarified little by little in the form in which the appearance of the background portion of the character is delayed with respect to the appearance of the character. Fade-in display with excellent decorativeness is realized. Further, according to the fade-out display of the present embodiment, fade-out display with excellent decorativeness is realized in which the OSD image is erased little by little in a form in which the disappearance of the character is delayed with respect to the disappearance of the background portion of the character.

The embodiment of the present invention has been described above.
As described above, according to the present embodiment, an on-screen display excellent in visibility and decoration is realized by a configuration that does not use data for controlling transparency for each pixel, such as α channel data of α blend. Can do.

It is a block diagram which shows the structure of the on-screen display apparatus which concerns on embodiment of this invention. It is a figure which shows the structural example of the mixing process part which concerns on embodiment of this invention. It is a figure which shows the output of the transmittance | permeability control part of the blend control part which concerns on embodiment of this invention. It is a figure which shows the example of a display image of the on-screen display apparatus which concerns on embodiment of this invention. It is a figure which shows the relationship between the display image and blend level of the on-screen display apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... OSD display control part, 2 ... OSD image generation part, 3 ... Blend control part, 4 ... Mixing process part, 5 ... Delay processing part, 31 ... Character color register, 32 ... Match detection part, 33 ... Transmission control part , 41... Mask controller, 42... Mask circuit, 43.

Claims (4)

An on-screen display device that superimposes and displays a sub-image on a part of a base image,
A match detection means for detecting whether each pixel value of the sub-image matches a set pixel value that is a preset pixel value;
For each pixel of the sub-image, the mixing ratio of the pixel to the pixel of the base image, the mixing ratio set to the pixel whose pixel value matches the set pixel value, and the set pixel value match the pixel value Mixing ratio setting means for setting the mixing ratio to be set to different pixels to different values;
Mixing means for mixing each pixel of the sub-image with a pixel of the base image at a mixing ratio set to the pixel ;
A control device that selectively designates one of a plurality of transparency levels in the mixing ratio setting means;
The mixing ratio setting unit is configured to set a mixing ratio to be set for pixels of the sub-image in which the set pixel value matches the pixel value, and a mixing to be set for pixels in the sub-image in which the set pixel value and the pixel value do not match. a ratio as specified transparency level is low, the on-screen display and wherein said that the mixing ratio of the pixels of the sub-picture is varied to be larger in said mixing means. The on-screen display device according to claim 1,
The transparency level is such that the mixing ratio setting means sets the mixing ratio set to the pixels of the sub-image whose pixel value does not coincide with the set pixel value is the mixing ratio of the pixels of the sub-image in the mixing means is 100. Including a transparency level of less than 100%, which is a transparency level of less than 100%,
The blending ratio setting means sets a blending ratio to be set for the pixel of the sub-image whose pixel value matches the set pixel value when the transparency level of less than 100% is designated. An on-screen display device, wherein the mixing ratio of the sub-image pixels in the mixing unit is set to be larger than the mixing ratio set for the sub-image pixels whose values do not match. The on-screen display device according to claim 2,
The on-screen display device, wherein the control unit performs fade-in display of the sub-image by gradually decreasing a transparency level set in the mixing ratio setting unit at the start of display of the sub-image. The on-screen display device according to claim 2 or 3,
The on-screen display device, wherein the control unit performs fade-out display of the sub-image by gradually increasing a transparency level set in the mixing ratio setting unit at the end of the display of the sub-image.