Abstract:
A picture output apparatus comprising a generator unit configured to generate an on-screen signal having a plurality of gradations, an acquisition unit configured to acquire color information which corresponds to each of the gradations possessed by the on-screen signal generated by the generator unit, and a converter unit configured to apply a highlight converting process to the on-screen signal based on the color information which corresponds to each of the gradations acquired by the acquisition unit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2004-347313, filed Nov. 30, 2004, the entire contents of which are incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a picture output apparatus and a picture output method for outputting a signal for on-screen display.  
         [0004]     2. Description of the Related Art  
         [0005]     As is well known, in an on-screen display (OSD) on a character by character basis, for example, there is provided a so-called highlight function of highlighting only a specific character in a screen by changing a color of the specific character. This highlight function can carry out highlight conversion for changing two colors between a color of a specific character itself and a background color of the character.  
         [0006]     On the other hand, in recent years, in a television receiver apparatus or the like, a gray scale font is used to improve the apparent resolution. However, in the case where this gray scale font has been used, there is an inconvenience that highlight conversion relevant to an intermediate gradation cannot be carried out with a current highlight function.  
         [0007]     In Jpn. Pat. Appln. KOKAI Publication No. 10-126710, there is disclosed a technique of using an externally rewritable look up-table to carry out a process for superimposing a main screen and a graphics screen on each other, thereby making it possible to change the contents of the superimposing process (such as overlay, mask, monochrome processing, or highlight) without any circuit change merely by rewriting the contents of the look-up table.  
         [0008]     However, in this technique described in Jpn. Pat. Appln. KOKAI Publication No. 10-126710, the contents of the look-up table are rewritten. Thus, the contents of the superimposing process on the entire screen can be changed. However, unlike the highlight function, it is impossible to highlight only a specific character in a screen by changing a color of the specific character.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     According to one aspect of the present invention, there is provided a picture output apparatus comprising: a generator unit configured to generate an on-screen signal having a plurality of gradations; an acquisition unit configured to acquire color information which corresponds to each of the gradations possessed by the on-screen signal generated by the generator unit; and a converter unit configured to apply a highlight converting process to the on-screen signal based on the color information which corresponds to each of the gradations acquired by the acquisition unit.  
         [0010]     According to another aspect of the present invention, there is provided a picture output method comprising: a first step of generating an on-screen signal having a plurality of gradations; a second step of acquiring color information which corresponds to each of the gradations possessed by the on-screen signal based on input color information and gradation number; and a third step of applying a highlight converting process to the on-screen signal based on the color information which corresponds to each of the gradation acquired by the second step. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0011]      FIG. 1  is a block diagram showing a first embodiment of the present invention, the block diagram being adopted to explain a television receiver apparatus;  
         [0012]      FIG. 2  is a view adopted to explain an example of a gray scale font before highlight conversion, the font being displayed on the television receiver apparatus in the first embodiment;  
         [0013]      FIG. 3  is a view adopted to explain an intermediate color generated by a highlight processor unit of the television receiver apparatus in the first embodiment;  
         [0014]      FIG. 4  is a view adopted to explain an example of a gray scale font after highlight conversion, the font being displayed on the television receiver apparatus in the first embodiment;  
         [0015]      FIG. 5  is a view adopted to explain an example of an intermediate color before and after highlight conversion, the intermediate color being generated by the highlight processor unit of the television receiver apparatus in the first embodiment;  
         [0016]      FIG. 6  is a view adopted to explain another example of an intermediate color before and after highlight conversion, the intermediate color being generated by the highlight processor unit of the television receiver apparatus in the first embodiment;  
         [0017]      FIG. 7  is a flow chart adopted to explain a processing operation of the highlight processor unit of the television receiver apparatus in the first embodiment;  
         [0018]      FIG. 8  is a block diagram showing a second embodiment of the present invention, the block diagram being adopted to explain a television receiver device;  
         [0019]      FIG. 9  is a block diagram showing a third embodiment of the present invention, the block diagram being adopted to explain a television receiver device;  
         [0020]      FIG. 10  is a view adopted to explain in detail a CLUT unit of the television receiver apparatus in the third embodiment; and  
         [0021]      FIG. 11  is a block diagram showing a fourth embodiment of the present invention, the block diagram being adopted to explain a television receiver apparatus. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]     Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.  FIG. 1  shows a television receiver apparatus  1  explained in the first embodiment. That is, in  FIG. 1 , reference numeral  12  denotes an antenna. A television broadcast signal received by this antenna  12  is supplied to a receiver unit  14  via an input terminal  13 .  
         [0023]     This receiver unit  14  generates R, G, and B signals by applying a predetermined decoding process to the input television broadcast signal. For example, in the case of Japan, the receiver unit  14  applies a channel selecting process, a demodulating process, an national television system committee (NTSC) decoding process or the like to the television broadcast signal.  
         [0024]     Then, each of the R, G, and B signals generated by the receiver unit  14  is supplied to a blending unit  15 . The blending unit  15  superimposes an on-screen signal output from a highlight processor unit  16  with respect to each of the input R, G, and B signals and supplies the superimposed signals to a picture display unit  17  which consists of a cathode ray tube (CRT) or the like and displays the supplied signal as a picture.  
         [0025]     Here, the on-screen signal is generated by an on-screen signal generator unit  18 . In the on-screen signal generator unit  18 , an OSD controller  20  generates an on-screen signal based on operational information supplied from an operating unit  19  which includes a remote controller or the like, for example.  
         [0026]     That is, the OSD controller  20  reads out an on-screen signal from a font read only memory (ROM)  22 , and outputs the read-out signal to the highlight processor unit  16  in accordance with a command from the operating unit  19  and a display timing based on horizontal and vertical sync signals generated by a timing generator unit  21  based on the RGB signals output from the receiver unit  14 .  
         [0027]     The on-screen signal includes a font having a plurality of gradations, like a gray scale font, for example, and is composed of a blend value α used by the blending unit  15  and each of the R, G, and B signals. The blend value α may be stored in a font ROM  22  or may be generated by the OSD controller  20 .  
         [0028]     In addition, the OSD controller  20  generates and outputs a control signal for setting ON/OFF of a highlight function; a color before and after highlight conversion (two colors, color 1 and color 2); or a gradation number of a gray scale or the like, with respect to the highlight processor unit  16  based on a command from the operating unit  19 .  
         [0029]     Further, the timing generator unit  21  generates and outputs a highlight control signal indicating a timing to highlight with respect to the highlight processor unit  16  based on each of the R, G, and B signals output from the receiver unit  14 .  
         [0030]     Then, the highlight processor unit  16  computes each intermediate color before and after highlight conversion, in the case where highlight conversion has been made with respect to a gray scale font based on colors (two colors, color 1 and color 2) before and after highlight conversion and a gradation number of a grayscale, the colors and the gradation number having been input via the operating unit  19 .  
         [0031]     Computational formulas of intermediate colors, in the case where the gradation number of the gray scale is “m”, are shown below. 
 
Intermediate color 1=color 1±[|color 1−color 2|×1/( m− 1)]
 
Intermediate color 2=color 1±[|color 1−color 2|×2/( m− 1)]
 
Intermediate color ( m− 2)=Intermediate color 1=color 1+[|color 1−color 2|×( m− 2)/( m− 1)] 
 
 (note that − is assigned in the case where color 1≧color 2, and + is assigned in the case where color 1&lt;color 2) 
 
         [0032]     The highlight processor unit  16  computes and holds a respective one of the R, G, and B signals of an intermediate color according to a full gradation of the gray scale before and after highlight conversion, in accordance with these computational formulas.  
         [0033]     Then, in the case where an active highlight control signal is supplied from the timing generator unit  21 , the highlight processor unit  16  determines whether or not an input on-screen signal coincides with a color before highlight conversion, based on the computation result and the setting of the OSD controller  20 . In the case where the determination result is negative, the highlight processor unit  16  outputs the on-screen signal as is. In the case where the determination result is affirmative, the processor unit  16  converts the signal to data after conversion, and outputs the converted data.  
         [0034]      FIG. 2  shows a font before highlight conversion, in the case where the gradation number of the gray scale is 4. In this case, in the figure, a pre-conversion color 1 indicated by fine dotted line corresponds to black; and a pre-conversion color 2 indicated by a whitened portion corresponds to white. In the figure, a pre-conversion intermediate color 1 indicated by a right upward hatching and a pre-conversion intermediate color 2 indicated by the right downward hatching correspond to intermediate colors obtained by dividing the gradation into three equal sections from black to white.  
         [0035]     Here, information on the pre-conversion colors 1 and 2 and post-conversion colors 1 and 2 (black and white) and the gradation number (4) of the gray scale are input from the operating unit  19 , whereby the highlight processor unit  16  generates pre-conversion intermediate colors 1 and 2 before highlight conversion and post-conversion intermediate colors 1 and 2 after highlight conversion, as shown in  FIG. 3 . In this manner, a gray scale font after highlight conversion as shown in  FIG. 4  can be obtained.  
         [0036]      FIG. 5  shows values of the R, G, and B colors in the case where highlight conversion for inverting black and white has been made in a four-step gray scale font, as shown in  FIGS. 2 and 4 . In the conventional values after conversion, only the colors 1 and 2 are inverted. On the contrary, in the values after conversion according to the embodiment, it is found that the intermediate values 1 and 2 are inverted as well.  
         [0037]      FIG. 6  shows values of the R, G, and B colors in the case where highlight conversion for inverting red and yellow has been made in a four-step gray scale font. In the conventional values after conversion, only the colors 1 and 2 are inverted. On the contrary, in the values after conversion according to the present embodiment, it is found that the intermediate values 1 and 2 are inverted as well.  
         [0038]      FIGS. 5 and 6  each show an example of inverting the colors 1 and 2 before highlight conversion. However, even when different colors are used before and after highlight conversion, computation of an intermediate color can be carried out smoothly without any problem.  
         [0039]      FIG. 7  shows a flow chart illustrating a processing operation of the above described highlight processor unit  16 . That is, when processing is started (in step S 1 ), the highlight processor unit  16  records two colors, namely, pre-conversion color 1 or 2 and post-conversion color 1 or 2, respectively, before and after highlight conversion, the two colors having been input by a user, in step S 2 .  
         [0040]     Then, in step S 3 , the highlight processor unit  16  computes required pre-conversion color intermediate colors 1 to (m−2) from the pre-conversion colors 1 and 2 and the gradation number “m” of the gray scale and computes required post-conversion intermediate colors 1 to (m−2) from the post-conversion colors 1 and 2 and the gradation number “m” of the gray scale; and then, holds these computation results.  
         [0041]     Then, in step S 4 , the highlight processor unit  16  inputs an on-screen signal output from the OSD controller  20 . In step S 5 , the highlight processor unit  16  determines whether or not the input on-screen signal coincides with the highlight pre-conversion color [pre-conversion colors 1 and 2 and pre-conversion intermediate colors 1 to (m−2)] in units of pixels, for example.  
         [0042]     In the case where the determination result is negative (NO), the highlight processor unit  16  outputs the font data as is on the input on-screen signal to the blending unit  15 , in step S 7 , and terminates processing (in step S 8 ).  
         [0043]     In the case where it has been determined that font data on the on-screen signal input in the step S 5  coincides with the highlight pre-conversion color (YES), the highlight processor  16  converts the font data to the highlight post-conversion color [post-conversion color 1 and 2 and post-conversion intermediate colors 1 to (m−2)] in step S 6 ; outputs the converted color to the blending unit  15  in step S 7 ; and terminates processing (in step S 8 ).  
         [0044]     Here, the blending unit  15  blends each of the R, G, and B signals which is an output of the receiver unit  14  and the on-screen signal output from the highlight processor unit  16  with each other. Although an example of this blending method is shown below, the blending method, of course, is not limited to this example. That is, an output of the blending unit  15  is as follows: 
 
Each of R, G, and B signals×(1−α)+on-screen signal×α(note that 0≦α≦1) 
 
         [0045]     According to the first embodiment, by inputting the two pre-conversion colors 1 and 2 and two post-conversion colors 1 and 2 before and after highlight conversion and the gradation number “m” of the gray scale, the highlight processor unit  16  computes and holds the required pre-conversion intermediate colors 1 to (m−2) and post-conversion intermediate colors 1 to (m−2), and then, converts the colors to the highlight post-conversion colors to be output to the gray scale font which correspond to the highlight pre-conversion colors. Therefore, it is possible to easily achieve a highlight function which corresponds to the gray scale font.  
         [0046]     The intermediate colors are computed by the OSD controller  20  without being computed by the highlight processor  16 , so that it is possible to notify the highlight processor unit  16  of the result and hold the notified result.  
         [0047]     In  FIG. 1 , although an on-screen signal is stored in the font ROM  22 , the signal may be stored in a random access memory (RAM) instead of the ROM. Further, the OSD controller  20  may generates a font by way of computation without using the ROM or RAM.  
         [0048]     Further, while the foregoing first embodiment has described a construction having an antenna  12  and a receiver unit  14  because the embodiment is directed to a television receiver apparatus  11 , the present invention is not limited to the television receiver apparatus  11 . That is, instead of the antenna  12  or the receiver unit  14 , for example, the present invention can be widely applied to equipment for outputting a picture signal such as a digital versatile disk (DVD) reproducing unit or an hard disk drive (HDD).  
         [0049]     By operation of the operating unit  19 , it is possible to provide settings which cause the highlight processor unit  16  not to carry out highlight conversion. In this case, the highlight processor unit  16  operates so as to output the input on-screen signal as is to the blending unit  15 .  
         [0050]      FIG. 8  shows a second embodiment of the present invention. In  FIG. 8 , like constituent elements in  FIG. 1  are designated by like reference numerals. Referring to  FIG. 8 , the OSD controller  20  outputs an on-screen signal to an OSD RAM  23 , and creates an on-screen display image. Then, the highlight processor unit  16  operates so as to sequentially reads out fonts from the OSD RAM  23 , and configure an on-screen display (raster processing).  
         [0051]     In this way, by using the OSD RAM  23 , it becomes possible to create a screen more slowly than a data speed requested by the picture display unit  17 . Thus, the use of the OSD RAM  23  is effective in the case where a processing speed of the OSD controller  20  is low or at the time of creating a complicated on-screen display.  
         [0052]      FIG. 9  shows a third embodiment of the present invention. In  FIG. 9 , like constituent elements in  FIG. 1  are designated by like reference numerals. Referring to  FIG. 9 , a color look-up table (CLUT) unit  24  is interposed between the highlight processor unit  16  and the blending unit  15 . Generally, the CLUT unit  24  is composed of a RAM, and a color look up table as shown in  FIG. 10  is used.  
         [0053]     In this case, the OSD controller  20  generates an Index signal which corresponds to an on-screen signal. The Index signal is produced as an address of the CLUT unit  24 . Then, in this third embodiment, the highlight processor unit  16  carries out highlight conversion for converting an Index signal to another Index signal.  
         [0054]     The highlight processor unit  16  also reads out the corresponding color information from the CLUT unit  24  based on the gradation number and input Index signal of the gray scale instructed from the OSD controller  20 . A method of computing an intermediate color from the read out color information is identical to that according to the first embodiment. The computation result and the Index signal with which each data portion of α, R, G, or B of the CLUT unit  24  coincides are stored, respectively. At the time of highlight conversion, in the case where an input Index signal coincides with an Index signal before highlighted, the input Index signal is converted to an Index signal after highlighted. In the case where the signal does not coincide, the input Index signal is output as is.  
         [0055]     The CLUT unit  24  outputs the corresponding blend value α and each of the R, G, and B signals while the Index signal supplied from the highlight processor unit  16  is produced as an address.  
         [0056]     The Index signal is composed of fewer bits than a total bit number of each of the R, G, and B signals. For example, assuming that the Index signal is 8 bits, and the blend value a and each of the R, G, and B signals are 8 bits, respectively, the bit number of the Index signal becomes smaller by 24 bits with respect to 32 bits of color data including the blend value α.  
         [0057]     At the same time, although the displayable color number is limited to index 8 bits=256 colors, this is sufficient as an on-screen. Thus, a circuit scale can be reduced without any problem.  
         [0058]     In addition, the CLUT unit  24  is interposed, whereby the OSD controller  20  and the highlight processor unit  16  carry out processing of an Index signal. In this case, 8-bit processing will suffice, thus making it possible to reduce a circuit scale.  
         [0059]     There is a need for the highlight processor unit  16  to carry out processing by way of an Index signal, and thus, the OSD controller  20  notifies the highlight processor unit  16  of the Index signal of a color to be highlighted. In the case where the highlight processor unit  16  carries out computation of an intermediate color or in the case where the OSD controller  20  does, an access is provided to the CLUT unit  24  based on the Index signal notified by the OSD controller  20 , and computation is carried out after acquiring a color signal value.  
         [0060]     While the present embodiment has described that the blend value α and each of the R, G, and B signals are 8 bits, the present invention, of course, is not limited thereto.  
         [0061]      FIG. 11  shows a fourth embodiment of the present invention. In  FIG. 11 , like constituent elements in  FIG. 9  are designated by like reference numerals. Referring to  FIG. 11 , the OSD controller  20  outputs an Index signal to an OSD RAM  25  and creates an on-screen display image. In order to create the on-screen display image by way of the Index signal, the OSD RAM  25  can be composed of fewer bits than that of each of the R, G, and B signals.  
         [0062]     According to this fourth embodiment, as in the second embodiment, it becomes possible to create a screen more slowly than a data speed requested by the picture display unit  17  by using the OSD RAM  25 . Thus, the use of the RAM is effective in the case where a processing speed of the OSD controller  20  is low or at the time of creating a complicated on-screen display.  
         [0063]     The present invention is not limited to the embodiments. At a stage of carrying out the invention, the present invention can be applied to a graphics process or the like of a personal computer (PC), for example, and constituent elements can be embodied by variously modifying them without departing from the spirit of the invention.  
         [0064]     In addition, a variety of inventions can be formed by properly combining a plurality of constituent elements disclosed in the above describe embodiments. For example, some of all the constituent elements disclosed in the embodiments may be eliminated. Further, the constituent elements according to the different embodiments may be properly combined with each other.