JPH08181889A - Contour correction device - Google Patents

Abstract

PURPOSE: To provide a contour correction device capable of contour-correcting only title superimposition selectively. CONSTITUTION: A contour correction circuit 50 generates delay digital component video signals RD, GD and BD in which digital component video signals Rin , Gin and Bin are delayed by one line in line memory 52, 60 and 68, respectively and generates digital component video signals RE, GE and BE to which contour emphasis is applied by comparators 54, 62 and 70 and encoders 56, 64 and 72. While, it is judged whether or not the present positions of the signals RD, GD and BD are within a title superimposition area by a line position judging circuit 10, then, a judging signal is outputted. The selectors 58, 66 and 74 of the contour correction circuit 50 output by selecting the signals RE, GE and BE when the present line positions of the signals RD, GD and BD are within the title superimposition area and output by selecting the signals RD, GD and BD when they are not within the title superimposition area based on the judging signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contour correcting device, and more particularly to a contour correcting device that makes it easy to see a subtitle superimposed on the lower portion of a video frame.

[0002]

2. Description of the Related Art In video software such as foreign movies and karaoke, as shown in FIGS. 10 (1) and 10 (2), a caption super showing words or lyrics may be combined at the bottom or right end of the frame. To make it easier to see the subtitle supermarket, the contour of the character may be emphasized by passing the video signal through the contour correction device.

[0003]

However, since the conventional contour correcting device corrects the contour of the entire frame, a normal image portion other than the subtitle supermarket (see FIG. 10 (1)).
There is also a problem that the contour correction is also performed on A of FIG. 10 and A ′ of FIG. 10 (2), resulting in an unnatural image.
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a contour correction device capable of selectively performing contour correction only on a subtitle super.

[0004]

In the contour correcting apparatus according to the present invention, a discriminating circuit for discriminating whether or not the scanning position of the video signal is within a predetermined area of the frame, and the discriminating circuit determines that the scanning position is within the predetermined area of the frame. A contour correction circuit that emphasizes and outputs the contour of the video signal while it is determined to be included is provided.

In another contour correcting apparatus according to the present invention, a line color discriminating circuit for discriminating whether or not there are only two types of line colors for each line of a video signal, and a line color discriminating circuit for discriminating only two types of line colors. A contour correction circuit that emphasizes and outputs the contour of the video signal for each of the generated lines is provided.

According to still another contour correction device of the present invention,
A line position discriminating circuit that discriminates whether each line of the video signal is within a predetermined area of the frame, a line color discriminating circuit that discriminates whether each line of the video signal has only two types of line colors, and a line position discriminating circuit. The contour that is output by emphasizing the contour of the video signal for the line that is determined to be within the predetermined area of the frame by the line and the line color determination circuit determines that there are only two types of line colors And a correction circuit.

In still another contour correction device according to the present invention,
The line color discriminating circuit discriminates for each line of the video signal whether or not the color of the line is only a predetermined two kinds of colors, and at this time, a period other than the specific two kinds of colors is constant. In the following case, the existence of colors other than these two specific types of colors is ignored.

[0008]

According to the contour correcting device of the present invention, it is determined whether the scanning position of the video signal is within the predetermined area of the frame, and while it is determined that the scanning position is within the predetermined area of the frame, The contour of the video signal is emphasized and output. As a result, the contour correction is performed only in a predetermined area in the frame where the subtitle super is synthesized, so that it is possible to prevent the image from becoming unnatural in the area in which the subtitle super is not synthesized.

According to another contour correction device of the present invention,
For each line of the video signal, it is determined whether or not there are only two types of line colors, and for the lines for which only two types of line colors have been determined, the contour of the video signal is emphasized and output. The area of the subtitle supermarket is usually 2 with a character color such as white and a background color such as black.
Since it is formed by types, when subtitles are combined in the lower part of the frame, only the subtitles are contour-corrected, so it is possible to avoid unnatural images in areas where subtitles are not combined. In addition, when the subtitle super is not combined, it is possible to prevent the image in the entire frame from being unnatural.

According to still another contour correction device of the present invention, it is determined whether the position of the line for each line of the video signal is within a predetermined area of the frame, and there are only two types of line colors for each line of the video signal. It is determined that the position of the line is within the predetermined area of the frame,
In addition, the contour of the video signal is emphasized and output for the line for which the line color is determined to be only two types. This allows
Even if it happens that there are only two types of line colors in areas other than the subtitle superimposing area, there is no possibility that the contour will be erroneously corrected to give an unnatural image.

According to still another contour correction device of the present invention, the line color discrimination circuit discriminates for each line of the video signal whether or not the color of the line is only two predetermined specific colors. At this time, when the duration of the colors other than the specific two types of colors is less than a certain period, the existence of the colors other than the specific two types of colors is ignored. As a result, the subtitle super is formed with a specific character color and a specific background color, but due to the rounding of the video signal, the character color changes from the character color to the background color at the boundary between the character and the background. Even if there is a change, the line of the subtitle super can be surely discriminated and the contour correction of the subtitle super can be performed.

[0012]

1 is a circuit diagram of a contour correcting apparatus according to an embodiment of the present invention. It is assumed that the contour correction apparatus of FIG. 1 performs contour correction for R, G, B digital component video signals by a non-interlaced scanning method in which the size of one frame is 525 lines × 858 pixels. The effective image area is 480 lines (line positions 46 to 525) x 7 excluding the vertical blanking period of 45 lines (line positions 1 to 45) and the horizontal blanking period of 154 pixels.
The size is 04 pixels. Then, it is assumed that the subtitle super is composed in an area of 61 lines whose line positions at the bottom of the effective screen are 465 to 525. Also, R, G,
Various sync clocks paired with the B digital component video signal (a frequency which becomes L only during the last line of the vertical blanking period of one frame 29.97 Hz frame clock FCK, a frequency which becomes L only at the last part of the horizontal blanking period) 15.734 kHz line clock LCK, frequency that becomes L only in the portion immediately before the horizontal blanking period 15.734
A line clock LCK 'of kHz and a pixel clock PCK of frequency 13.5 MHz having a period for one pixel (one sample period of a digital component video signal) are to be input (frame clock FCK, line clocks LCK, LCK'). (See FIGS. 2, 4, and 6).

In FIG. 1, R _in , G _in , and B _in are digital component video signals input from the outside, and are 0 to 255 (sync tip tip 0, black level = 1).
6, the peak level = 235). Reference numeral 10 is a line position discriminating circuit for discriminating whether or not the line position of the digital component video signal is within the subtitle super area, and delays R _in , G _in , and B _in by one line _in the contour correction circuit described later. When the line positions n of the delayed digital component video signals R _D , G _D , and B _D are in the range of 465 to 525, the H level is output, and when they are not, the L level is output. Reference numeral 12 is a counter for inputting the frame clock FCK to the preset terminal and inputting the line clock LCK to the clock terminal, preset 44 at the falling edge of the frame clock FCK, and then the line clock LC
Each time K is input, it is incremented by 1 to count the line position n of the delayed digital component video signals R _D , G _D , and B _D. 14 indicates the count value of the counter 12 by 46
5 and 525, and outputs an H level when 465 ≦ count value of the counter 12 ≦ 525, and outputs an L level otherwise.

A line color discrimination circuit 20 discriminates whether each line of the digital component video signals of R _in , G _in and B _in inputted from the outside is formed by only two kinds of colors, white and black. , The determination result is output during the scanning period of the next line. When it is formed of only two kinds of colors, white and black, it outputs H level, and otherwise outputs L level. 22, 26, and 30 are R _in , G _in , and B _in , respectively.
Of the R _in , G _in , and B _in are individually compared with each other by comparing the levels of R _in , G _in , and B _in individually with each other and outputting an H level at a high level between 216 and 235. And a comparison circuit that outputs an H level when the level is 35 or less, and 34 is a comparison circuit 22 or 2.
An AND circuit which is provided on the output side of 6 and 30 and outputs an H level when the digital component video signals of R _in , G _in , and B _in almost reach the white level, 36 is a comparison circuit 24, 28, 32 R _in , G provided on the output side of
_This is an AND circuit that outputs an H level when the digital component video signals of _in and B _in have almost reached the black level (here, the sync chip is also treated as a black level, but there is no particular problem. 28, 32
16 to 3 for the R _in , G _in , and B _in levels, respectively.
It may be configured to output the H level when the low level is between 16 and 35 as compared with 5.

Numeral 38 is provided on the output side of the AND circuits 34 and 36, and the digital component video signals of R _in , G _in and B _in have almost reached the white level or the black level, and either of the AND circuits 34 or 36. When the output is H level, it outputs L level, the digital component video signals of R _in , G _in and B _in are _in a color level different from white or black, and the outputs of the AND circuits 34 and 36 are both. NOR circuit that outputs H level when L level,
A counter 40 inputs the output of the NOR circuit 38 to the clear terminal and inputs the pixel clock PCK to the clock terminal. While the L level is being input from the NOR circuit 38, the counter 40 is in the clear state and the count value is 0. , NOR circuit 3
When the output of 8 becomes H level, the pixel clock PCK
Each time you input, the count is incremented by 1 and R _in , G _in ,
The duration of the state _{in which} the B _in digital component video signal is _in a color that is neither white nor black is counted. Reference numeral 42 is a comparison circuit, which counts the count value of the counter 40 by 5 (for 5 pixels).
In comparison with, the L level indicating that there is no color other than white and black is output for less than 5, and the H level indicating the presence of colors other than white and black is output for the first time when 5 or more.

As described above, if the digital component video signals of R _in , G _in , and B _in have a color state that is neither white nor black less than 5, it indicates that there is a color other than white and black H.
The level is not output only when the line colors are white and black, but when the waveform of the digital component video signal changes from white level to black level or from black level to white level. This is to prevent erroneous determination that another color exists between white and black.

44 is an R / S-flip-flop (hereinafter,
(Abbreviated as R / S-FF), when the line clock LCK is input to the S terminal, a set state is set and the Q terminal output is set to the H level, and thereafter, the H level is input to the R terminal from the comparison circuit 42. Then, it resets and drops the Q terminal output to L level. In the case of normal video software such as movies, it is usual that two or more colors exist in one line including the subtitle super. If the Q terminal output goes to H level at the beginning of the line and H continues until the end of the line, there is no color other than the two colors of white and black on the line this time, and in the end, there are two colors of white and black. It turns out that there are only kinds of colors. Also, when the Q terminal output goes to H level at the beginning of the line and then drops to L level in the middle of the line, it can be seen that colors other than white and black exist for this line.

Reference numeral 46 designates the Q terminal output of the R / S-FF44 as D
It is a D-flip-flop (hereinafter abbreviated as D-FF) which is input to a terminal and a line clock LCK 'is input to a clock terminal. The R / S-FF4 is provided immediately before the start of the next line.
By latching the Q terminal output of No. 4, the discrimination signal indicating whether or not there are only two kinds of colors of white and black on the current line is output from the Q terminal during the period of the next line. D-FF4
It is shown that when the Q terminal output of No. 6 is at the H level, only two kinds of colors are present, and at the L level, colors other than white and black are also present.

Reference numeral 50 denotes a contour correction circuit, which has R _in , G _in ,
Among the lines of the digital component video signal of B _in , the line position determination circuit 10 enters the subtitle super area, and the line color determination circuit 20 determines that the line color is only two types, white and black. A correction for emphasizing the contour is performed on the formed line and output as digital component video signals of R _out , G _out , and B _out .

52, 60 and 68 are R _in , G _in and B, respectively.
_in a delayed one line R _D, G _D, line memory for outputting the delayed digital component video signal of B _D, 54,62,70 each, R _D, G _D, the level of B _D compared to 216 A comparator circuit that outputs an H level when 216 or more, and an L level when less than 216, 5
6, 64 and 72 are individually compared circuits 54, 62 and 7 respectively.
It is an encoder ( _RD , GD) that outputs 235 when the 0 output is at the H level and outputs 16 when it is at the L level to output the contour-corrected digital component video signals of R _E , G _E , and B _E (R _D , G _D , B _D , R _E , G _E , and B _E, see FIGS. 5 and 7. When the delayed digital component video signals of R _D , G _D , and B _D have almost white levels, and each has a level of 216 or higher, it is replaced with 235 which is a perfect white level. In the case of a subtitle supermarket of two colors of white and black, the contour of the character is sharpened by setting the black level other than the white level to the complete black level.

Reference numerals 58, 66 and 74 denote R _D , G _D and B, respectively.
Delayed digital component video signal of _D and R _E , G
A selector for selectively selecting and outputting the contour-corrected digital component video signals of _E and B _E. Reference numeral 76 is an AND circuit that ANDs the output of the line position determination circuit 10 and the output of the line color determination circuit 20 and outputs a select signal. The select signal is 465 to 52 in which the line position n corresponds to the subtitle super area for each line of the delayed digital component video signals of R _D , G _D , and B _D.
When it is between 5 and there are only two kinds of colors of white and black in the line, it becomes H level, and the other becomes L level. Each of the selectors 58, 66 and 74 receives the L level select signal from the AND circuit 76 and receives the line memory 5
The delayed digital component video signals of R _D , G _D , and B _D input from 2, 60, and 68 are R _out , G _out , and B.
_When the H level select signal is output, the contour correction digital component video signals input from the encoders 56, 64 and 72 are output as R _out and G.
Output as _out and B _out .

Next, the operation of the above embodiment will be described with reference to FIGS. 3 is a time chart showing the operation of the line position discriminating circuit, FIG. 4 is a time chart showing the operation of the color discriminating circuit in the caption super, and FIG. 5 is a time chart showing the operation of the contour correction circuit in the caption super.
6 is a time chart showing the operation of the color discrimination circuit other than the subtitle super, FIG. 7 is a time chart showing the operation of the contour correction circuit other than the subtitle super, and FIG. 8 is an explanatory diagram showing the scanning operation in the subtitle super.

When there is a subtitle super, the line position discrimination circuit 10 counts the line position n of R _D , G _D , and B _D output from the line memories 52, 60, and 68 of the contour correction circuit 50 with the counter 12, Between 465 and 525 corresponding to the super area, the comparison circuit 14 outputs the H level determination signal indicating that the line position is in the subtitle super area, and outputs the other L level (see FIG. 3). Therefore, while the line position n of R _D , G _D , and B _D is 1 to 464 which is the normal image area, the AND circuit 76 of the contour correction circuit 50 outputs the L level select signal, and thus the selectors 58 and 66, 74 selects R _D , G _D , and B _D output from the line memories 52, 60, and 68, and outputs them as R _out , G _out , and B _out . As a result, the normal image area is not unnaturally edge-enhanced. On the other hand, the line position n of R _D , G _D , and B _D is 465.
Since the comparison circuit 14 outputs the H level when it is in the subtitle super area of ~ 525, the selectors 58, 6
The selection of 6 and 74 is left to the discrimination result in the line color discrimination circuit 20 (see FIGS. 5 and 7).

The line color discrimination circuit 20 includes R _in , G _in and B
Based on the input digital component video signals _in per line, detects a period in which almost white level by the comparator circuit 22,26,30 and AND circuit 34, comparator circuit 24,28,32 and AND circuit 36 AND circuit 34 detects the period when the black level is almost
And the outputs of 36 are taken, and a signal which becomes H only during a period which is neither a white level nor a black level is inputted to the clear terminal of the counter 40, and the continuation period of the period which is neither a white level nor a black level is determined. Count. And counter 4
The count value of 0 is compared with 5 by the comparison circuit 42. If the count value is less than 5, L indicating that there is no color other than white and black is output, and the count value exceeds 5 in the middle of one line. When it does, H indicating that there is a color other than white and black is output.

As shown in FIG. 8, when the current line position n of R _in , G _in , and B _in is 475 that hangs over the subtitle character in the subtitle super area, R at the boundary from the background to the character.
_in , G _in , and B _in normally rise from 35 or less to 216 or more in a short time less than 5 cycles of the pixel clock PCK, and at the boundary from the character to the background, 5 cycles of the pixel clock PCK from 216 to 35 or less. Get down in less than a short time. Therefore, n _in R _in , G _in , and B _in =
During scanning of the line 475, the operation of the line color discrimination circuit 20 becomes as shown in FIG. 4, the count value of the counter 40 never becomes 5 or more, and the output of the comparison circuit 42 maintains the L level. Then, the Q output is set to H by the input of the line clock LCK at the start of the n = 475 line of R _in , G _in , and B _in , and the R / S-FF 44 outputs the H output during scanning of 475 lines. The D-FF 46 which maintains the line clock LCK ′ at the end of the same line receives R /
The Q output of the S-FF 44 is latched to set the Q output to the H level, and during scanning of n = 476 lines of R _in , G _in , and B _in , there are only two types of lines of n = 475, white and black. The determination signal H indicating that is output.

The scanning period of n = 476 lines of R _in , G _in and B _in is the scanning period of n = 475 lines of R _D , G _D and B _D , and the line position discriminating circuit during this period. 10 and the AND circuit 76 of the contour correction circuit 50 which receives the H level from the line color discrimination circuit 20 outputs the H level as a select signal. The selector 58 that receives the H-level select signal inputs the signals R _E , G _E , and B that are input from the encoder 56.
Select _E. The encoder 56 uses n of R _D , G _D , and B _D.
= 475 lines, 216 and 216 are replaced with 235, and less than 216 are replaced with 16 and R _{E is} contour-corrected,
Since G _E and B _E are output, R _out , G _out , and B _out in which the contour of the subtitle super-character is emphasized from the selector 58.
Is output (see FIG. 5). In the same manner for the other lines hanging on subtitling characters, contours emphasized R _out, G _out, B _out are output.

As described above, the current line positions of R _D , G _D , and B _D are in the subtitle super area,
R _D, G _D, only contour-corrected R _out when both of the presence in the current line only specific two types of black and white B _D is satisfied, G _out, since B _{ou t} is output ,
Only the white letters in the subtitle supermarket can be emphasized to make it easier to see. The line color discrimination circuit 20 does not discriminate that there is any color other than white and black unless the count value of the counter 40 is 5 or more. Therefore, R _in , G _in Even if all or one of B _in and B _in changes, the contour can be surely emphasized. Also, for some reason, R _D , G _D , and B _D are n = 1 to 1
Even if the line color discrimination circuit 20 erroneously discriminates a certain line and outputs the H level when the image is in the normal image area 464, the line position discrimination circuit 10 outputs the L level discrimination signal in the normal image area. Is output,
The AND circuit 76 does not output the H-level select signal. As a result, it is possible to prevent the normal image from being unnatural due to incorrect contour correction.

When there is no subtitle super, when there is no subtitle super, R _in , G _in , and B _in
The current line position n is 475 in the subtitle super area
However, it is normal for colors other than white and black to exist in the middle of one line, and as shown in FIG. 6, the count value of the counter 40 becomes 5 or more at a certain timing, and the comparison circuit 42 becomes H level. Output level. The output of the comparison circuit 42 is n =
R / S-set at the start of scanning 475 lines
Since it is input to the R terminal of the FF44, when the output of the comparison circuit 42 becomes H, the R / S-FF44 is reset and Q
The terminal goes to L level, and DF occurs immediately before the start of the next line.
Latch to F46. As a result, the D-FF 46 is in the scanning period from the Q terminal to the line of n = 476, that is, R
During the scanning period of n = 475 when viewed from _D , G _D , and B _D ,
The Q terminal of the D-FF outputs an L level discrimination signal indicating that there are colors other than white and black on the line.

Therefore, the AND circuit 7 of the contour correction circuit 50
6 outputs an L level select signal based on the discrimination signal input from the line color discrimination circuit 20, so that the selector 5
8, 66 and 74 are line memories 52, 60 and 68, respectively.
R _D , G _D , and B _D output by are selected, and R _out ,
Output as G _out and B _out (see FIG. 7). As a result, the outline of the normal image in the subtitle super area is not artificially emphasized.

Even when the current line position n of R _in , G _in and B _in is within the normal image area of 1 to 464, colors other than white and black exist in the middle of one line. In the same manner as in the case of FIG. 6, the line color discrimination circuit 20 outputs an L level discrimination signal indicating that there are colors other than white and black in the current line during the scanning period of the next one line. Output to. If, for some reason, R _D , G _D , and B _D are n
= 1 to 464, when the line color discrimination circuit 20 erroneously discriminates a certain line and outputs H level, the line position discrimination circuit 10 outputs L level in the normal image area. Therefore, the AND circuit 76 does not output the H-level select signal. As a result, it is possible to prevent the normal image from being unnatural due to incorrect contour correction.

According to this embodiment, when the subtitle super is not present at the bottom of the frame, when the current line position n of R _D , B _D , and G _D is within the normal image area of 1 to 464. The line position discrimination circuit 10 outputs an L level discrimination signal, and when n is in the subtitle super area of 465 to 525, the line color discrimination circuit 20 outputs an L level discrimination signal, and the selectors 58, 66, 74 with R _D ,
Since B _D and G _D are selected, it is possible to avoid erroneous contour enhancement for one frame.

On the other hand, when the subtitle super is present at the bottom of the frame, the line position discriminating circuit 10 is provided only when the current line position n of R _D , B _D , and G _D overlaps the subtitle super in the subtitle super area. And the line color discrimination circuit 20 both output an H level discrimination signal. At this time, the line color discrimination is performed even if all or any of R _in , G _in , and B _in changes at the boundary between the background and the character. The circuit 20 outputs the H-level discrimination signal indicating that there are only two kinds of colors of the background and the character, and the selectors 58 and 6 are provided.
Since 6 and 74 are made to select R _E , B _E and G _E , it is possible to surely carry out the contour emphasis of the subtitle super.

When the subtitle super is present at the bottom of the frame and the current line position n of R _D , B _D , and G _D is within the subtitle super area, but does not overlap the subtitle super characters. , The line color discrimination circuit 20 is L
When the current line position n of R _D , B _D , and G _D is within the normal image area, the line position determination circuit 10 outputs the L level determination signal. Since the selectors 58, 66 and 74 are made to select R _D , B _D and G _D , it is possible to avoid erroneous contour enhancement.

In the above embodiment, the output AN of both the line position discriminating circuit 10 and the line color discriminating circuit 20 is AN.
Although D is taken and the select signals of the selectors 58, 66 and 74 are created, the line color discrimination circuit 20 is omitted and the discrimination signal output of the line position discrimination circuit 10 is directly used as the select signal. It is also possible to omit 10 and use the discrimination signal output of the line color discrimination circuit 20 as it is as the select signal. Line position determination circuit 10
When the output of is used as a select signal as it is, the contour is emphasized only in the subtitle super area, so when the subtitle super exists, the characters are easy to see, and the normal image area becomes unnatural regardless of the presence or absence of the subtitle super. Can be avoided. When the output of the line color discrimination circuit 20 is used as it is as the select signal, only the subtitle super characters are contour-emphasized when the subtitle super is present, so that it is possible to prevent the normal image other than the subtitle super characters from being unnaturally emphasized. it can.

Further, the line color discrimination circuit 20 discriminates whether or not there are only two kinds of colors, white and black, at the current line position, but there is also a subtitle supermarket represented by white characters on a blue background. Therefore, it may be determined whether there are only two types of colors other than the combination of white and black. Further, the invention can be applied to an interlaced video signal, or can be applied to a video signal of a standard other than 525 lines × 858 pixels in one frame.

When the subtitle super is synthesized in the area of the line position n = 46 to 106 of the frame, the comparing circuit 14 of the line position discriminating circuit 10 keeps the H level while the count value of the counter 12 is 46 to 106. The output may be performed, and the L level may be output during other periods.

In the above embodiment, the line position discriminating circuit 10 has been described as an example of the discriminating circuit for discriminating whether the scanning position of the video signal is within the predetermined area of the frame. As shown in 10 (2), in the case of combining in the range of 778 to 858 pixels in one line at the right end, the line position determination circuit 10 is replaced with the scanning position determination circuit 80 shown in FIG. The scanning position determination circuit 80 compares the counter 82 to which the line clock LCK is input to the preset terminal PRS and the pixel clock PCK is input to the clock terminal, and a comparison circuit 84 for comparing whether the count value of the counter 82 is within the range of 778 to 858. It consists of and. The counter 82 is preset with 154 when the line clock LCK becomes L level, and thereafter, the counter 82 counts up by 1 each time the pixel clock PCK is input. When the count value of the counter 82 is between 778 and 858, the comparison circuit 84
To H level, and L level at other periods. Then, the output of the comparison circuit 84 is directly used as a select signal for the selectors 58 and 6 of the contour correction circuit 50 of FIG.
By inputting 6 and 74, the outline can be emphasized only in the subtitle super area in one frame, and it is possible to avoid unnatural emphasis in the normal image area.

[0038]

According to the contour correcting apparatus of the present invention, it is determined whether the scanning position of the video signal is within the predetermined area of the frame, and it is determined that the scanning position is within the predetermined area of the frame. By emphasizing and outputting the contour of the video signal during this period, the contour is corrected only in a predetermined area in the frame where the subtitle super is synthesized, so that the image becomes unnatural in the area where the subtitle super is not synthesized. Can be avoided.

According to another contour correction device of the present invention,
For each line of the video signal, it is determined whether there are only two types of line colors, and for lines that have been determined to have only two types of line colors, the contour of the video signal is emphasized and output. Since the area is usually formed with two types of character color such as white and background color such as black, when subtitle superimposition is combined at the bottom of the frame,
Since only the subtitle super is contour-corrected, it is possible to prevent the image from becoming unnatural in the area where the subtitle super is not combined. You can prevent it from becoming natural.

According to still another contour correction device of the present invention, it is possible to determine whether the position of the line for each line of the video signal is within a predetermined area of the frame, and there are only two types of line colors for each line of the video signal. It is determined that the position of the line is within the predetermined area of the frame,
In addition, since the line of which the line color is determined to be only two types is emphasized and output, the outline of the video signal is output, so that the line color happens to be only two types outside the area where the subtitle superimposition is combined. However, there is no chance that the contour will be erroneously corrected to give an unnatural image.

According to still another contour correction device of the present invention, the line color discrimination circuit discriminates for each line of the video signal whether the color of the line is only two predetermined specific colors. At this time, when the duration of the color other than the specific two types of color is less than a certain period, the subtitle super is configured to ignore the existence of the color other than the specific two types of colors, so that the subtitle super However, even if the character color changes from the character color to the background color at the boundary between the character and the background due to the rounding of the video signal, it is certain that the character color and the background color will change. It is possible to determine the line of the subtitle super and to perform contour correction of the subtitle super.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a contour correction device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a video signal standard.

FIG. 3 is a time chart showing the operation of the line position determination circuit.

FIG. 4 is a time chart showing an operation of a line color discrimination circuit in a subtitle supermarket.

FIG. 5 is a time chart showing the operation of the contour correction circuit in the subtitle supermarket.

FIG. 6 is a time chart showing the operation of the line color discrimination circuit other than the subtitle supermarket.

FIG. 7 is a time chart showing the operation of the contour correction circuit other than the subtitle supermarket.

FIG. 8 is an explanatory diagram of a scanning operation in a subtitle supermarket.

FIG. 9 is a circuit diagram of a scanning position determination circuit according to a modified example of the present invention.

FIG. 10 is an explanatory diagram of a video frame including a subtitle super.

[Explanation of symbols]

10 line position discrimination circuit 20 line color discrimination circuit 50 contour correction circuit 80 scanning position discrimination circuit

Claims (4)

[Claims] 1. A discriminating circuit for discriminating whether a scanning position of a video signal is within a predetermined area of a frame, and a discriminating circuit for discriminating the video signal while the scanning position is discriminated as being within a predetermined area of the frame. A contour correction device comprising: a contour correction circuit for emphasizing and outputting a contour; 2. A line color discriminating circuit for discriminating only two types of line colors for each line of the video signal, and a contour of the video signal for each line discriminated by the line color discriminating circuit as having only two types of line colors. And a contour correction circuit that emphasizes and outputs the contour correction circuit. 3. A line position discriminating circuit for discriminating whether each line of the video signal is within a predetermined area of the frame, and a line color discriminating circuit for discriminating whether each line of the video signal has only two types of line colors. , The line position discriminating circuit discriminates that the position of the line is within a predetermined area of the frame, and the line color discriminating circuit discriminates only two types of line colors. And a contour correction circuit for outputting the contour correction circuit. 4. The line color discriminating circuit discriminates for each line of the video signal whether or not the line color is formed by only two predetermined types.
The contour correction device according to claim 2 or 3, wherein the presence of a color other than the specific two types of colors is ignored when the duration of the color other than the types of colors is less than a certain period. .