JP2007110303A - Contour correction circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contour correction circuit in which contour correction output same as that of prior arts is obtained even when RGB processing is applied to signals from an input to a display element part. <P>SOLUTION: In the contour correction circuit, a luminance signal extract circuit extracts from red, green, and blue video signals, a horizontal high frequency band pass filter 103 and a vertical high frequency band pass filter 104 extract horizontal and vertical high frequency components from the luminance signal, prescribed constants are respectively multiplied with filter outputs, and thereafter the products are summed by an adder circuit, and an output of the adder circuit is added respectively to the red, green, and blue video signals. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a contour correcting apparatus for correcting a contour of a video signal.

  As a conventional contour correcting device, for example, there is a device described in Section 903 of the Television Image Information Engineering Handbook / Television Society (1990) used as a conventional example of JP-A-5-252421. FIG. 6 shows the configuration of a conventional contour correction apparatus. In FIG. 6, reference numeral 601 denotes a video signal input terminal, 602 a horizontal high-pass filter, 603 a vertical high-pass filter, 604 and 606 adders, 605 a multiplier, and 607 an output terminal. The operation of the contour correction apparatus configured as described above will be described. First, the luminance signal input from the input terminal 601 is supplied to the horizontal high-pass filter 602, the vertical high-pass filter 603, and the adder 606. The The horizontal high-pass filter 602 extracts a high-frequency portion in the horizontal direction, and the vertical high-pass filter 603 extracts a high-frequency portion in the vertical direction, and each high-frequency component is supplied to the adder 604. The output signal from the adder 604 is supplied to the multiplier 605 and the amplitude is adjusted with a predetermined gain. An output signal from the multiplier 605 is supplied to the adder 606, and an addition output with the luminance signal from the input terminal is output from the output terminal 607.

As a result, high frequency components in the horizontal and vertical directions are added to the input luminance signal, the contour portion of the image corresponding to the input luminance level is emphasized, and an image with improved blur can be obtained (for example, Patent Literature 1).
JP-A-5-252421

  However, in the configuration as described above, when the input signal is an RGB (red, green, blue) signal, the contour correction signal is processed for each of the RGB video signals, unlike when the contour correction is performed with the luminance signal. Unlike the conventional case of performing contour correction with a luminance signal, a portion where the RGB ratio is lost due to the contour correction processing occurs, and a color different from the original color is displayed in the contour portion. Was.

  SUMMARY OF THE INVENTION In view of this point, the present invention has an object to provide a contour correction device that can obtain the same contour correction output as before even when RGB processing is performed from the input to the display element portion.

  Further, in addition to the above object, the invention according to claim 4 is suitable for the case where the user prefers the contour correction in RGB when the user prefers the contour correction in RGB. It is an object of the present invention to provide a contour correction apparatus capable of performing the above process.

  In order to achieve the above object, a luminance signal extracting means for extracting a luminance signal from a red video signal, a green video signal and a blue video signal, and a horizontal direction from the luminance signal output from the luminance signal extracting means. A horizontal high-pass filter that extracts a high-frequency component, a vertical high-pass filter that extracts a high-frequency component in the vertical direction from the luminance signal, and a first constant that multiplies the output of the horizontal high-pass filter by a predetermined constant. Multiplication means, second multiplication means for multiplying the output of the vertical high-pass filter by a predetermined constant, and first addition means for adding outputs from the first multiplication means and the second multiplication means A second addition means for adding the output of the first addition means to the red video signal; a third addition means for adding the output of the first addition means to the green video signal; The output of the first adding means is added to the video signal. Is characterized in that a fourth adding means for calculation.

  Further, according to a second aspect of the present invention, the luminance extraction unit multiplies each of the red video signal, the green video signal, and the blue video signal by a fixed constant, and adds each multiplication result obtained from the multiplication unit. It is characterized by seeking.

  Further, in the third aspect of the present invention, the first addition means adding the multiplication results of the horizontal high-pass filter and the vertical high-pass filter includes a red video signal, a green video signal, and a blue video signal. The same value is added to each.

  According to a fourth aspect of the present invention, there is provided a luminance signal extracting means for extracting a luminance signal from a red video signal, a green video signal and a blue video signal, an output of the luminance extracting means and a video signal inputted from an input terminal. An input switching means for selecting and outputting, a horizontal high-pass filter for extracting a horizontal high-frequency component from the output of the input switching means, and a vertical for extracting a high-frequency component in the vertical direction from the luminance signal A high-pass filter, a first multiplier for multiplying the output of the horizontal high-pass filter by a predetermined constant, a second multiplier for multiplying the output of the vertical high-pass filter by a predetermined constant, First addition means for adding outputs from the first multiplication means and the second multiplication means, and second addition means for adding the output of the first addition means to an input signal It is characterized by.

  According to a fifth aspect of the present invention, the input switching means is a first input switching means for switching between a red video signal and a luminance signal, a second input switching means for switching between a green video signal and a luminance signal, It is characterized by comprising third input switching means for switching between a video signal and a luminance signal.

  According to a sixth aspect of the present invention, the horizontal high-pass filter and the vertical high-pass filter are connected to the first, second, and third input switching means in the same configuration, and each color component On the other hand, the configuration is such that the horizontal / vertical high-frequency component of the luminance component or the horizontal / vertical high-frequency component of each color can be added.

  The present invention extracts a luminance component by calculation from RGB (red, green, blue) video signals input to an input terminal, performs horizontal and vertical contour correction processing on the luminance component, and this contour correction component. Is added to each of R, G, and B, an image without blur similar to the case where the contour correction processing is performed on the luminance component without converting the input video signal into the luminance and color components can be realized. Furthermore, by providing an input switching circuit, if the blur is improved when there are few luminance components and contour correction is performed with RGB, it is possible to use a video signal that has been subjected to contour correction processing with RGB. The effect is great.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
The contour correction apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a contour correction apparatus according to Embodiment 1 of the present invention.

  The contour correction apparatus shown in FIG. 1 has an input terminal 101 to which RGB (red, green, and blue) video signals are input, and a luminance signal that extracts a luminance signal from the three-color video signals input to the input terminal 101. An output from the extraction circuit 102, a horizontal high-pass filter 103 that extracts a high-frequency portion in the horizontal direction, a vertical high-pass filter 104 that extracts a high-frequency portion in the vertical direction, and an output from the horizontal high-pass filter 103 are arbitrary. , A multiplier 106 that multiplies the output from the vertical high-pass filter 104 by an arbitrary gain, an adder 107 that adds the outputs from the multipliers 105 and 106, and an adder 107 The adder 108 adds the RGB video signals input from the input terminal 101 to the output from the input terminal 101, and the output terminal 110.

  Next, the operation of the video signal processing apparatus according to the first embodiment configured as described above will be described.

  In FIG. 1, when RGB video signals are input to the input terminal 101, the luminance signal extraction circuit calculates a luminance signal from the RGB video signals. Here, the following relationship is established between RGB, luminance Y, and color differences Cr and Cb.

Y = 0.299R + 0.587G + 0.114B (1)
Cr = 0.713 (R−Y)
Cb = 0.564 (BY)
When calculating RGB using luminance and color difference from this equation: G = Y−0.7144Cr−0.4350Cb
R = Y + 1.4025Cr
B = Y + 1.730 Cb
It becomes.

  As a result, when the contour correction is performed on the RGB video signal with the luminance component, the luminance component is obtained by adding the same level to each of the RGB, so the contour correction signal also adds the same signal level to each of the GBR video signals. It will be good. For this reason, first, the luminance signal extraction circuit 102 multiplies each coefficient for each of RGB according to the calculation formula shown in (1) to obtain a luminance signal. The luminance signal obtained by the luminance signal extraction circuit 102 is input to the horizontal high-pass filter 103 and the vertical high-pass filter 104, and each contour component is extracted. The contour components are multiplied by, for example, a gain arbitrarily adjusted by the user in the multipliers 105 and 106, and the result is added by the adder 107 to obtain a contour correction signal.

  By adding the contour correction signal output from the adder 107 to the RGB signal input from the input terminal by the adder 108, the contour correction processing by the luminance signal is performed on the input RGB video signal.

  FIG. 2 shows an example of the display state of the screen, and the horizontal contour correction processing operation will be described using color bar signals. At this time, the signal levels of one line of RGB are as shown in FIGS. 3 (a), 3 (b), and 3 (c). When the calculation shown in (1) is performed from this RGB video signal, the luminance signal shown in FIG. 3 (d) is obtained. As a result of extracting a high-frequency portion from the luminance signal by the horizontal high-pass filter 102 and the vertical high-pass filter 103 and further performing gain adjustment and horizontal / vertical addition processing, the contour correction signal shown in FIG. ) Is obtained.

  By adding the contour correction signals to FIGS. 3A, 3B, and 3C, the contour-corrected RGB video signals shown in FIGS. 3F, 3G, and 3H are obtained. . When the contour correction is performed using the luminance signal as in the circled portion in FIG. 3F, contour correction that cannot be obtained when the contour correction processing is performed with RGB as it is can be performed.

  As described above, according to the first embodiment, a luminance component is extracted by calculation from RGB (red, green, blue) video signals input to the input terminal, and horizontal and vertical contours for the luminance component are extracted. By performing correction processing and adding this contour correction component to each of RGB, the same blur as when the contour correction processing is performed on the luminance component without converting the input video signal into luminance and color components. It is possible to obtain an image without any image.

(Embodiment 2)
Next, a video signal processing apparatus according to Embodiment 2 will be described with reference to FIGS. FIG. 4 is a block diagram of the video signal processing apparatus according to the second embodiment. Parts corresponding to those in the first embodiment shown in FIG.

  In FIG. 4, reference numeral 401 denotes an input switching circuit that switches and outputs each of the RGB video signals input from the input terminal 101 and the video signal output from the luminance signal extraction circuit 102.

  The operation of the video signal processing apparatus according to the second embodiment of the present invention having the above configuration will be described below.

  When RGB video signals are input to the input terminal 101, the luminance signal extraction circuit 102 calculates luminance signals from the RGB video signals. In the input switching circuit 401, a mode (contour correction by RGB or luminance) selected by a user (not shown) of either the RGB video signals input from the input terminal 101 or the luminance signal from the luminance signal extraction circuit 102 is selected. According to the output.

  When the output of the input switching circuit 401 is RGB, the horizontal high-pass filter 103 and the vertical high-pass filter 104 extract the horizontal and vertical high-frequency components for each of RGB when the output of the input switching circuit 401 is RGB. When the output 401 is a luminance component, horizontal and vertical high-frequency components in the luminance component are extracted. The high-frequency components extracted by the horizontal high-pass filter 103 and the vertical high-pass filter 104 are subjected to horizontal and vertical gain adjustments by multipliers 105 and 106, and then both components are added by an adder 107. In 108, it is added to the RGB video signal input from the input terminal 101.

  FIG. 5 shows the operation when the color bar signal of FIG. 2 is input to the input terminal 101, and the signal levels of RGB are as shown in FIGS. 5 (a), (b), and (c). Yes. If an RGB video signal is output from the input switching circuit 401 at this time, horizontal and vertical high-frequency components are extracted for each of the RGB colors, and after gain adjustment, addition processing is performed on the video from the input terminal 101. 5 (d), (e), and (f) results are obtained. When the luminance signal extracted by the luminance signal extraction circuit 102 is output from the input switching circuit 401, horizontal and vertical high-frequency components are extracted from the luminance signal, and gain adjustment is performed. After that, addition processing is performed on the video from the input terminal 101, and the results shown in FIGS. 5 (g), (h), and (i) are obtained. The input switching circuit 401 performs RGB contour processing or luminance contour processing according to user switching (not shown) and outputs the result from the output terminal 108.

  As described above, according to the second embodiment, by providing an input switching circuit, blurring can be improved when the contour correction is performed with RGB with less luminance components, or when the user performs contour correction with RGB. Can be used, it is possible to use a video signal that has been subjected to contour correction processing with RGB, and its practical effect is great.

  The contour correction apparatus according to the present invention extracts a luminance component by calculation from RGB (red, green, blue) video signals input to an input terminal, and performs horizontal and vertical contour correction processing on the luminance component. By adding this contour correction component to each of RGB, a blur-free image similar to the case where the contour correction processing is performed on the luminance component without converting the input video signal into the luminance and color components is obtained. realizable. Furthermore, by providing an input switching circuit, if the blur is improved when there are few luminance components and contour correction is performed with RGB, it is possible to use a video signal that has been subjected to contour correction processing with RGB. The effect is great.

The block diagram of the outline correction apparatus in Embodiment 1 of this invention The figure which showed one example of the screen display for demonstrating operation | movement of the outline correction apparatus in Embodiment 1 of this invention Waveform diagram explaining the operation of the contour correction apparatus according to Embodiment 1 of the present invention Block diagram of the contour correction apparatus in Embodiment 2 of the present invention Waveform diagram explaining the operation of the contour correction apparatus according to Embodiment 2 of the present invention The block diagram which shows the structural example of the conventional contour correction apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 101,601 Input terminal 102 Luminance signal extraction circuit 103 Horizontal high-pass filter 104 Vertical high-pass filter 105,106 Multiplier 107,108 Adder 109 Output terminal 401 Input switching circuit

Claims (6)

Luminance signal extraction means for extracting a luminance signal from a red video signal, a green video signal, and a blue video signal, and a horizontal high frequency band for extracting a high frequency component in the horizontal direction from the luminance signal output from the luminance signal extraction means A vertical high-pass filter that extracts a high-frequency component in the vertical direction from the pass filter, the luminance signal, first multiplication means for multiplying an output of the horizontal high-pass filter by a predetermined constant, and the vertical high-pass A second multiplying means for multiplying the output of the filter by a predetermined constant; a first adding means for adding the outputs from the first multiplying means and the second multiplying means; A second adding means for adding the output of the first adding means; a third adding means for adding the output of the first adding means to the green video signal; and the first adding means for the blue video signal. A fourth adding means for adding the outputs of Contour correcting device, characterized in that was e. The luminance extracting means multiplies each of a red video signal, a green video signal, and a blue video signal by a fixed constant, and adds each multiplication result obtained from the multiplication means to obtain the luminance extraction means. The contour correction apparatus according to 1. The first addition means adding the multiplication results of the horizontal high-pass filter and the vertical high-pass filter adds the same value to each of the red video signal, the green video signal, and the blue video signal. The contour correction apparatus according to claim 1, wherein: A luminance signal extracting means for extracting a luminance signal from a red video signal, a green video signal, and a blue video signal, and either the output of the luminance extracting means or a video signal input from an input terminal is selected and output. An input switching unit, a horizontal high-pass filter that extracts a high-frequency component in the horizontal direction from an output of the input switching unit, a vertical high-pass filter that extracts a high-frequency component in the vertical direction from the luminance signal, and the horizontal high-pass filter First multiplication means for multiplying the output of the bandpass filter by a predetermined constant; second multiplication means for multiplying the output of the vertical high-pass filter by a predetermined constant; the first multiplication means and the first A contour correction apparatus comprising: first addition means for adding outputs from two multiplication means; and second addition means for adding the output of the first addition means to an input signal. The input switching unit includes a first input switching unit that switches between a red video signal and a luminance signal, a second input switching unit that switches between a green video signal and a luminance signal, and a third that switches between a blue video signal and a luminance signal. 5. The contour correcting device according to claim 4, wherein the contour correcting device comprises: The horizontal high-pass filter and the vertical high-pass filter are connected to the first, second, and third input switching units in the same configuration, and the horizontal and vertical luminance components for each color component. 6. The contour correcting apparatus according to claim 4, wherein the contour correcting apparatus is configured to be able to add a high frequency component or a horizontal / vertical high frequency component of each color.

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