JP3173063B2 - Color adaptive contour enhancement device and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for enhancing the outline of an image by controlling luminance information in the image signal.

[0002]

2. Description of the Related Art Heretofore, there has been known a method of enhancing a contour portion of a subject in order to improve the sharpness and resolution of an image. For example, in the field of electronic video such as a television system, the outline of luminance information of video is emphasized. The control of the amount of horizontal and vertical enhancement of this type of contour enhancement is performed manually or by automatic gain control (AGC).
It was linked to the level. As the edge enhancement method corresponding to the color information of a video, there are a resolution deterioration correction (constant luminance signal processing) of a high chroma portion in the EDTV system and a detail improvement of a dark portion corresponding to a luminance level (adaptive emphasis).

[0003]

However, in the conventional apparatus, depending on the degree of the emphasis, not only the outline but also the noise of the image is emphasized, so that the image quality is degraded or the situation of the subject is reduced. Since the optimum degree of emphasis is different, an unnatural image may be obtained. The present invention solves the above problem, and focuses on a masking effect among human perceptual characteristics of an image, and changes the degree of enhancement of a contour portion of luminance information according to chromaticity information of an image signal. Accordingly, an object of the present invention is to provide a color-adaptive contour emphasizing device that is excellent in sharpness and resolution and can obtain an image with little noise.

[0004]

In order to achieve the above object, according to the present invention, there is provided a color information extracting means for extracting chromaticity information as color information from a video signal, and a method for generating a luminance signal from the video signal. Contour signal generating means for generating a contour signal from the luminance signal; and outputting the contour signal generated by the contour signal generating means to output information of the color information extracting means .
And a contour correcting means for correcting according to the scanning position of the image . According to a second aspect of the present invention, in the color adaptive contour emphasizing apparatus according to the first aspect, the color information extracting means is configured to uniformly extract the color information in the uniform perceived chromaticity diagram (u, v), (u ′, v ′). This is for extracting quantized chromaticity information. According to a third aspect of the present invention, in the color adaptive contour enhancing device according to the first aspect, the contour correcting means corrects the contour signal based on a masking effect which is a visual characteristic of the image. According to a fourth aspect of the present invention, a first step of extracting chromaticity information as color information from a video signal, a second step of generating a luminance signal from the video signal and generating an outline signal from the luminance signal, Chromaticity information
And a third step of correcting according to the scanning position of the image . According to a fifth aspect of the present invention, in the color adaptive contour enhancement method according to the fourth aspect, in the first step, the uniform perceived chromaticity diagram (u, v), (u ′, v ′) is used as color information.
Is a method for extracting chromaticity information that has been quantized uniformly. According to a sixth aspect of the present invention, in the color adaptive contour enhancing apparatus according to the first aspect, in the third step, the contour signal is corrected based on a masking effect which is a visual characteristic of the image.

According to the above arrangement and method, the color information extracting means extracts chromaticity information as color information from the video signal, and the contour signal generating means generates a luminance signal from the video signal and generates a contour signal from the luminance signal. Generate The contour correcting means corrects the contour signal generated by the contour signal generating means according to the output information of the color information extracting means and the scanning position of the image . This contour correction is made by focusing on the masking effect.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the present invention focuses on the masking effect of the human perceptual characteristics of an image. This masking effect will be described below.
The masking effect is one of human visual characteristics. For example, an outline of a figure is controlled by luminance information, and chromaticity information is controlled by an outline based on the luminance information. FIG.
Shows a state in which a luminance signal and a chromaticity signal of a certain video signal are superimposed in the horizontal direction.
b shows a chromaticity pattern. The contour of the chromaticity pattern b is blurred due to the narrow band frequency transmission characteristics of the television system. In the figure, ΔE corresponds to the saturation of a hue having chromaticity information, ΔL represents the luminance level of the luminance information (the degree of the luminance contour), and L represents the luminance level of the background.

FIG. 2 is an equivalent perceptual chromaticity diagram (u, v).
FIG. 4A is a chromaticity diagram, in which “a” denotes a frequency band of a chromaticity signal of 0.7 MHz, L = 10 [cd / m ² ], and ΔL =
B indicates the chromaticity range in which the masking effect can be visually recognized when 0, and b indicates the chromaticity range when the frequency band and L of the chromaticity signal are the same as above and ΔL = 10 [cd / m ² ]. Show. From the figure, it can be seen that the chromaticity distribution range to be masked widens outward from the achromatic chromaticity point c depending on the degree of the luminance contour (corresponding to ΔL). From this result, it can be said that the masking effect of the chromaticity contour by the luminance contour is extremely remarkable. Also, the narrow band hue of color vision, yellow-blue (referred to as yb), has a larger masking effect than the red-green (referred to as rg), which is a broadband hue. It is also known that even if there is a jitter in the pattern, which is a random shaking of the contour, if the luminance pattern has no jitter, it can be seen as a color image with a clear contour. In FIG. 2, R, G, B
Indicates the chromaticity point of the three primary colors of the receiving image of the NTSC standard, and indicates the C
The marks indicate achromatic chromaticity points.

According to the present invention, the outline of the luminance information is emphasized in accordance with the chromaticity information of the image, thereby masking the outline of the chromaticity signal with limited narrow band frequency transmission characteristics in the television system. To enhance the sense of sharpness and resolution of the image, and improve the quality of the image. In particular, in this embodiment, the visual narrow-band hue axis y-b
The luminance contour emphasis amount is controlled based on the chromaticity information focusing on the relationship between the chromaticity information and the broadband hue axis rg and the masking effect. For example, the luminance contour of the video signal having the chromaticity information near r-g with less masking effect is more emphasized than the case where the chromaticity information near yb is provided. Alternatively, the luminance contour of a video signal having chromaticity information with high saturation is more emphasized than that with low saturation. Further, as a secondary effect, the contour is enhanced as the color becomes darker, so that an apparatus using video signal processing other than the constant luminance method has an effect of improving the detail characteristics.

FIG. 3 shows a block configuration of the apparatus according to the present embodiment. Of the captured video signals R, G, B, signals R, B
Are input to a gain control amplifier (GC) for white balance 1 and 2 (WB) adjustment. G
The gains of C1 and GC2 are determined by a control signal from the WB control unit 3. The WB sensor 4 detects the color temperature of the illumination light source of the subject or an artificial light source such as a fluorescent lamp, and outputs information on the detection result to the WB control unit 3. The WB control unit 3 automatically performs WB adjustment on the captured video signal by outputting a predetermined control signal to each of the GC1 and GC2 according to the information. Note that the means of WB adjustment is not particularly limited to the above configuration. For example, an internal measurement type automatic WB adjustment in which the color temperature of an illumination light source or the like is detected from a video signal to perform WB adjustment may be used.

A video signal G, which is a video signal whose WB has been adjusted by the WB adjusting means, and output signals R and B of GC1 and GC2 are input to a signal processing section 5. In the signal processing section 5, the input signal undergoes normal video signal processing such as gamma correction and knee processing, and then generates color difference signals R'-Y 'and B'-Y' by matrix processing, and the narrow-band luminance signal YL.
', A luminance signal Y' is generated from the broadband luminance signal YH '. The color difference signals R'-Y 'generated by the signal processing unit 5,
The B'-Y 'and the luminance signal Y' are output to the encoder unit 6, and the color difference signal balance-modulates the color subcarrier fsc. The encoder unit 6 combines the luminance signal Y ′, the modulated wave, the color reference signal (burst signal), and the horizontal and vertical synchronization signals φH and φV to obtain a composite video signal Vs conforming to the target television standard. Generate The signal processing unit 5 includes a vertical contour signal generation unit (VA) for generating a contour signal.
P) 7 and a horizontal contour signal generation unit (HAP)
8 to perform edge enhancement by adding each edge signal to the luminance signal. The adjustment of the output signal levels of VAP7 and HAP8, that is, the control of the degree of contour enhancement, is performed by control signals Vcont and Hcont of the data processing unit 9, respectively.

FIG. 4 shows an example of the signal processing section 5 constituting the contour emphasizing means. First, a configuration for vertical contour enhancement will be described. The luminance signal YL generated by the signal processing unit 5
Is input to the delay unit 10 (hereinafter, referred to as DL), and the output signal is output to the synthesizing unit 11 and the VAP 7. The level of the vertical contour signal generated by the VAP 7 is adjusted by the control signal Vcont, output to the synthesizing unit 11, and synthesized with the luminance signal YL 'to become a signal in which the vertical outline is enhanced.

An example of the configuration of the VAP 7 is shown in FIG.
Here, the one using the delay means (1 HDL) 12 for one horizontal period time is shown. The input signal P (FIG. B) of the VAP 7 is delayed by one horizontal period time by the 1HDL 12 to become a signal Q (FIG. C), and the subtraction unit 13 performs a subtraction process (P-Q) on the signal P and the signal Q. You. The output signal R of the subtractor 13 is adjusted in level by the GC 14 whose gain is controlled by the control signal Vcont.
It is output to the synthesizing unit 11. The output of the synthesizing unit 11 is input to a Y 'generating unit 16 (described later) for generating a luminance signal Y'. As another configuration example of VAP7, two 1HD
Some use L. Next, as means for enhancing the horizontal contour, in FIG. 4, the luminance signal YH ′ generated by the signal processing unit 5 is input to the DL 15. The output signal is output to the HAP 8, the luminance signal YH ′ from the HAP 8 is output to the Y ′ generating unit 16, and the luminance signal Y ′ is generated by the output signal (vertical contour emphasized signal) of the synthesizing unit 11. The signal Y ′ is output to the combining unit 17. The level of the horizontal contour signal generated by the HAP 8 is adjusted by the control signal Hcont, output to the synthesizing unit 17, and synthesized with the luminance signal Y 'to enhance the horizontal and vertical outlines of the signal Y. '.

An example of the configuration of the HAP 8 is shown in FIG.
The input signal S of the HAP 8 (FIG. B) has a predetermined delay time Td.
And a reflected wave T (see FIG. C) due to the high impedance of the receiving end of the delay LC filter 18 (referred to as DLFIL), and is output to the subtraction unit 19.
The output signal V (FIG. E) of the DLFIL 18 is subjected to the subtraction processing (V−U) by the subtraction unit 19 with the composite wave U. As a result,
The signal W (FIG. F) is output. This signal means a horizontal contour signal. The level of the signal W is adjusted by the GC 20 whose gain is controlled by the control signal Hcont, and then output to the combining unit 17. Further, the output signal V of the DLFIL 18 becomes a luminance signal YH ′ delayed by Td and becomes Y ′
Output to the generation unit 16. By the way, Td is about 100ns
ec. Note that the resistance Ro in FIG.
Prevents the attenuation of the reflected signal of DLFIL,
And DLFIL18 serve as a buffer.

Next, the chromaticity / luminance extracting section 29 in FIG.
Will be described. The video signal G having undergone the WB adjustment by the WB adjusting means and the output signals R and B of the GC1 and GC2 are also provided in a matrix section (hereinafter referred to as an MTX section) 21,
The matrix signals W1, W2, and W3, which are respectively output to the signals 22 and 23, are determined according to the following equations. Output signal of MTX unit 21 W1 = R11 + Gm1 + Bn1 Output signal of MTX unit 22 W2 = R12 + Gm2 + Bn2 Output signal of MTX unit 23 It is a value that becomes a three primary color signal in a broad sense in color science. That is, there is a color system that uses the signals W1, W2, and W3 as tristimulus values. W1, W
2 and W3 are converted to analog-digital converters (A / D
) Are converted to quantized data. The A / D units 24, 25, and 26 are provided with band limiting filters for removing aliasing noise based on the sampling theorem for the input signal, and perform the conversion operation at the timing of the clock signal CLK1 having the sampling frequency f. The signal data of W1, W2, and W3 obtained from the A / D units 24, 25, and 26 are respectively divided by the division unit 2
7 and 28.

The division unit 27 outputs a division result W1 / W2 using the W1 signal as a numerator and the W2 signal as a denominator as signal data. Similarly, the division unit 28 outputs the division result W3 / W2 using the W3 signal as a numerator and the W2 signal as a denominator as signal data. The configuration of the dividers 27 and 28 may be a look-up table method using a memory, a divider having a logic configuration, or processing by a program in a microcomputer or the like. It is well known in chromatic science that W1 / W2 and W3 / W2 obtained in this way represent chromaticity information (chromaticity data) of the video signal. If the input signal data W2 in the division processing indicates 0 or a value meaning 0 (the denominator becomes a value equivalent to 0), for example, chromaticity data indicating an achromatic color or a chromaticity in the vicinity thereof is output. Is also good. The above processing may be used in the horizontal and vertical blanking periods of the video signal, the black level, and the like.

Next, the chromaticity data W1 / W2, W3 / W2
The state of the distribution of the quantization points on the chromaticity diagram will be described with an example. The imaging and video display system used now is NTS
It is assumed that the chromaticity data conforms to the C television standard, and the chromaticity data is developed on a CIE1976 UCS chromaticity diagram ((u ′, v ′) chromaticity diagram, uniform perceptual chromaticity diagram). Each MTX
The mixing ratio of the parts 21, 22, 23 is set as follows. Output signal of MTX unit 21 W1 = R (l = 1, m1 = n1 = 0) Output signal of MTX unit 22 W2 = 0.261R + 0.469G + 0.2 70B (12 = 0.261, m2 = 0.469, n2) = 0.270 0 ≦ W2 ≦ 1) Output signal of MTX section 23 W3 = B (13 = m3 = 0, n3 = 1)

The mixing ratio in the MTX section 22 is (u ', v
') The mixing ratio of the following equation, which represents the sum of stimuli (U + V + W) in the UVW color system, which is the color system of the chromaticity diagram, using the respective stimulus values R, G, and B in the NTSC standard RGB color system, This is the result of normalizing the W2 signal. U + V + W = 0.8482R + 1.5288G + 0.8773B From the above formula, W2 = 0.261R + 0.469G + 0.
270B 0 ≦ W2 ≦ 1 (0 ≦ R, G, B ≦ 1). Therefore, the chromaticity data W1 / W2, W3 / W2 mean the following equation. W1 / W2 = R / (0.261R + 0.469G + 0.270B) W3 / W2 = B / (0.261R + 0.469G + 0.270B) Here, focusing on the value range of each chromaticity data, 0 ≦ W1 / W2 ≦ 1 / 0.261, 0 ≦ W3 / W2 ≦
1 / 0.270, and the respective upper value ranges are very close.

Therefore, the mixing ratio of the MTX unit 22 is approximated,
For example, l2: m2: n2 = 0.261: 0.469: 0.27
0 = 1: 1.80: 1.03 is set to 12: m2: n2 = 1: 1.8: 1 = 0.263: 0.474: 0.263. As a result, the value range of the chromaticity data becomes equal to 0 ≦ W1 / W2, W3 / W2 ≦ 1 / 0.263, so that the division units 27 and 28 can use exactly the same configuration. 27, 28 designs,
The manufacturing cost can be reduced, and the division processing can be performed by time division using only one division unit. FIG. 7 shows the distribution of quantization points on the (u ′, v ′) chromaticity diagram where the chromaticity data W1 / W2, W3 / W2 obtained in this manner are shown on the (u ′, v ′) chromaticity diagram. And).

In FIG. 7, the circles of R, G and B indicate NTS.
The chromaticity points of the C standard three primary colors are shown, and the circle of C indicates the chromaticity point of the reference white. Each value of the chromaticity data W1 / W2, W3 / W2 corresponds to a coordinate value (from 0 to 31) when the (G, R) axis and the (G, B) axis are coordinate axes, respectively. It can be seen that the position determined by the value indicates the chromaticity coordinate value on the (u ′, v ′) chromaticity diagram. The distribution of the quantization points is evenly located on the chromaticity diagram plane along the axis. That is,
It can be said that quantization noise for human chromaticity perception is made uniform by uniformly quantizing the perceptual chromaticity diagram.
This is the basis for considering the minimum required number of bits when considering the quantization of chromaticity information with a finite number of bits.

FIG. 8 shows the distribution of quantization points in this example in the CIE 1960 UCS chromaticity diagram ((u, v) chromaticity diagram, uniform perceptual chromaticity diagram). The (u, v) chromaticity diagram, in which the stimulus sum of the UVW color system is the same, shows the same characteristics as described above. Further, as described above, the output signal W2 of the MTX unit 22 appropriately includes the R, G, and B stimulus values, and its value range is 0 ≦ W2 ≦ 1, so that the output signal W2 may be regarded as the luminance information of the video signal. It is possible (the quantized W2 signal is used as luminance data). For example, the W2 signal or a signal obtained by gamma-correcting the W2 signal may be used as YH ′ generated by the signal processing unit 5. In this example, the MTX units 21 and 23
Are 1: 0: 0 and 0: 0: 1, respectively, so that the MTX units 21 and 23 are eliminated, and the A / D units 24 and 26 are used.
, And the R and B signals may be directly input to the respective components. MTX unit 2
The mixture ratio of 1, 22, 23 has various values and combinations, but it can be generally said that the mixture ratio of the MTX units 21, 23 is the chromaticity data W1 / W2,
Two coordinate axes for determining the W3 / W2 value are determined, and the mixture ratio of the MTX unit 22 determines the distribution state of the quantization points on the chromaticity diagram plane. Therefore, these mixing ratios may be determined according to the function, purpose, cost, etc. of the apparatus.

The following table shows the mixing ratio of the MTX unit 22 in this embodiment, including other television standards.

[Table 1] TABLE1 Standard name NTSC PAL / SECAM HDTV II: m2: n2 0.261: 0.469: 0.270 0.199: 0.590: 0.211 0.189: 0.584: 0.227 ────────────────────────────────近似 Approximate example of upper mixture ratio 1 1: (1.7 to 1.8): 1 1: (2.8 to 3.0): 1 1: (2.6 to 3.1): 1 ────────────近似 Approximate example of upper mixture ratio 2 1: (2 to 3): 1 1: (2 to 3): 1 1 : (2 to 3): 1 where l2: m2: n2 is the mixture ratio of the MTX unit 22 for equal quantization of the (u ′, v ′) or (u, v) chromaticity diagram.

Approximate example 2 of TABLE1 can exist within a range that does not significantly impair the effects and objects of the present invention for various reasons such as simplification of the configuration of the imaging and receiving system and common use of each television standard. Value. Incidentally, in the description of this example, the (u ′, v ′) chromaticity diagram was used, but the UVW
The same can be said for the (u, v) chromaticity diagram in which the stimulus sum of the display system is the same. Also, assuming the NTS
Although the imaging and receiving system conforming to the C standard has been described, there is no practical problem with the currently operated system. The same is true for other television systems.

Next, another example in which only the mixing ratio of the MTX section 22 is changed will be described. Assuming that the mixture ratio of the MTX unit 22 is a Y stimulus value of the XYZ color system, that is, a value representing luminance, W2 = Y = 0.299R + 0.587G + 0.144B, 0 ≦ Y ≦ 1 (l2 = 0.299, m2 = 0.587, n2 = 0.1
14). Therefore, the chromaticity data W1 / W2, W3 /
W2 is given by the following equation. W1 / W2 = R / Y = R / (0.299R + 0.587G + 0.114B) W3 / W2 = B / Y = B / (0.299R + 0.587G + 0.114B) The above chromaticity data is (u, v) color FIG. 9 shows the distribution of the quantization points shown on the degree diagram (the number of quantization bits is 5).
Bit).

The chromaticity data W1 / W2, W3 / W2, and luminance data W2 of the input video signal obtained according to the above principle are output to the data processing unit 9. In the data processing unit 9, the input chromaticity data W1 / W2, W3 / W
The control of the amount of contour enhancement corresponding to the masking effect at the chromaticity coordinates designated by the control signal Vcon
Perform at t and Hcont. This control is performed, for example, as shown in FIG.
And the chromaticity data coordinate values (W1) obtained by uniformly quantizing the uniform perceptual chromaticity diagram plane shown in FIG.
/ W2, W3 / W2). The point of the qualitative weighting is as described at the beginning of this embodiment.

In the quantization example shown in FIG. 8, the chromaticity data represents a representative chromaticity having a uniform chromaticity based on human chromaticity perception, and the control method corresponding to the chromaticity data is chromaticity perception. This is a so-called perceptual control that enables setting of the degree of fine and smooth contour enhancement. Further, in this example, the weighting of the luminance data W2 is also possible. The point is that, when the subject of the video is dark or when the entire video is dark, the emphasis amount is suppressed so that noise and the like are not noticeable. In the case of FIG. 9 where the amount of enhancement is increased or the like, the luminance data W2 indicates the luminance (Y stimulus value) of the input video signal. It is expensive.

An example of data processing relating to the above-mentioned contents in the data processing section 9 will be described. The data processing unit 9 previously stores, in a memory or the like, a data group (hereinafter referred to as masking data) obtained by weighting the contour enhancement amount for the chromaticity data coordinates (W1 / W2, W3 / W2), By comparing or referencing with the masking data, a predetermined emphasis amount is instructed to VAP7 and HAP8 (look-up table method). Clock signals CLK2, φH, and φV are input to the data processing unit 9, and the above-described data processing is performed at the timing of these signals. CLK2 and C
LK1 is in a synchronous relationship and maintains a predetermined frequency ratio and phase difference. Further, since these are in synchronism with φH and φV, they may be formed from the chrominance subcarrier signal fsc, for example. Thus, in the data processing of the data processing unit 9,
It takes a certain amount of time from the input of the chromaticity data to the control of the contour enhancement amount by the VAP 7 and the HAP 8.

DL10 and DL15 in FIG. 4 are VAP7 and HA
This is delay means for adjusting the timing at which control of the signal is started at P8 and the timing of luminance signals YH 'and YL' corresponding to performing contour enhancement. DL31, 32
Are the luminance signals YH ', YL' and the color difference signals R'-Y ',
This is delay means for maintaining a predetermined phase relationship between B 'and Y'. By the way, VAP7, HAP8 of the data processing unit 9
It is preferable to control the amount of emphasis for each of them so that both the horizontal and vertical directions are visually natural and of the same level.

The components of the present invention operate as described above. Here, a modified example of the configuration of the chromaticity / luminance extraction unit 29 will be described again. Chromaticity / luminance extraction unit 29
Are the chromaticity data W1 / W2, W3 of the input video signal
Since the purpose is to extract / W2 and the luminance data W2, the configuration and combination of the MTX unit, A / D unit, division unit and the like as the means are not limited to those shown in FIG. The A / D units 24, 25, 26 are not fixed at the positions shown. For example, the A / D units 24, 25, and 26 can be placed in front of the MTX units 21, 22, and 23 to convert the input video signals R, G, and B into signal data.
The TX units 21, 22, and 23 have a digital processing configuration),
Also, they may be placed after the division units 27 and 28 (however, the division units 27 and 28 have an analog processing configuration). Further, the dividing units 27 and 28 may be configured as one. FIG. 11A shows the MTX units 21, 22, 23 and the division units 27, 28.
Is performed by one arithmetic unit 31 and can be realized by, for example, a look-up table method using a memory. FIG. 7B shows a case where only the luminance data W2 is generated by the MTX unit 33 in the configuration of FIG.

The input signals R, G,
B is a linear signal proportional to the amount of input light and is a signal directly related to image display, and may be taken from any component. The signal may be a signal subjected to the knee processing in the signal processing unit 5. Further, the signals R ′,
G 'and B' can also be taken, but in this case, the control characteristics of the outline enhancement for the input chromaticity information are different from those described above. In the present embodiment, the configuration of the signal processing 5 is analog processing, but the same principle can be applied to a digital processing configuration. In this case, there is an advantage that the timing with the data processing unit 9 can be easily limited, and the accuracy is improved.

Next, the function of the processing unit 9 by the control signal 30 input to the data processing unit 9 in FIG. 3 will be described.
1. It is possible to switch between the conventional edge enhancement method and the edge enhancement method according to the present invention, or to specify ON / OFF of the enhancement and the degree of the enhancement. 2. It is possible to specify the contour enhancement amount of a specific color. That is, the input chromaticity data W1 / W2, W3
Since the reproduced color of the input image can be specified from / W2, for example, by specifying a skin color and reducing the degree of the emphasis, human skin can be expressed smoothly. 3. AGC that automatically raises the input video signal level when the illuminance of the subject falls below the full aperture
Although there is a circuit, the contour enhancement amount and the noise level are reduced with the increase of the noise level of the video related to this operation, or in conjunction with the aperture value, by lowering the enhancement amount according to the whole or the chromaticity information and the luminance information. Video expression that achieves a balance with the above becomes possible. 4. CLK2, φ
By inputting H and φV, the current scanning position of the screen is determined, so that the contour enhancement amount is weighted to the screen position of the image. For example, the closer to the center of the screen, which is more noticeable, the higher the amount of enhancement. The source of the control signal 30 having these functions may be inside or outside the device using the present apparatus. As an external example, a function designation using an IC card or the like can be considered.

As described above, according to the present invention, attention is paid to the masking effect on the chromaticity information of an image,
Since the degree of edge enhancement of luminance information is controlled according to the scanning position of , the sense of sharpness and the sense of resolution of a video can be improved. Therefore, for example, an effect of improving the feeling of color fringing with respect to color fringing caused by the narrow band transmission frequency characteristic of a color signal in a television system can be obtained. Further, noise is reduced because extra emphasis by chromaticity information of the subject is not performed, and, automatically contour emphasis matching the visual characteristics due Masking effect is obtained in accordance with the chromaticity information, for example, more
It is possible to increase the amount of emphasis on the contour of the center of the screen
As a result , a natural image expression can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a relationship between a luminance signal and a chromaticity signal of a video signal.

FIG. 2 is a uniform perception chromaticity diagram.

FIG. 3 is a block diagram of an outline emphasis device according to an embodiment of the present invention;

FIG. 4 is a configuration diagram of a signal processing unit.

FIG. 5 is a configuration of a vertical contour signal generation unit and a signal waveform diagram of each unit.

FIG. 6 is a diagram illustrating a configuration of a horizontal contour signal generation unit and a signal waveform diagram of each unit.

FIG. 7 is a distribution diagram of quantization points on a chromaticity diagram.

FIG. 8 is a distribution diagram of quantization points on a chromaticity diagram.

FIG. 9 is a distribution diagram of quantization points on a chromaticity diagram.

FIG. 10 is an explanatory diagram of a masking effect.

FIG. 11 is a configuration diagram illustrating another example of the chromaticity / luminance extraction unit.

[Explanation of symbols]

 Reference Signs List 5 signal processing section 7 vertical contour signal generation section 8 horizontal contour signal generation section 9 data processing section 29 chromaticity / luminance extraction section

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 9/44-9/78 H04N 1/46

Claims (6)

(57) [Claims] 1. A color information extracting means for extracting chromaticity information as color information from a video signal, a contour signal generating means for generating a luminance signal from the video signal and generating a contour signal from the luminance signal, and The contour signal generated by the generating means is output to the output information of the color information extracting means ,
A color adaptive contour emphasizing device comprising: a contour correcting means for correcting according to a scanning position . Wherein the color information extraction unit, equally perceived chromaticity diagram as color information (u, v), (u' , v') uniformly in an amount
2. The color adaptive contour enhancing device according to claim 1, wherein child chromaticity information is extracted. 3. An apparatus according to claim 1, wherein said contour correcting means corrects the contour signal based on a masking effect which is a visual characteristic of the image. 4. A first step of extracting chromaticity information as color information from a video signal, a second step of generating a luminance signal from the video signal and generating an outline signal from the luminance signal. A color adaptive contour enhancement method, comprising: a third step of correcting a contour signal according to chromaticity information and an image scanning position . 5. In a first step, color information is uniformly represented in a uniform perceived chromaticity diagram (u, v), (u ′, v ′).
5. The color adaptive contour enhancement method according to claim 4, wherein the quantized chromaticity information is extracted. 6. The color adaptive contour correction / enhancement method according to claim 1, wherein in the third step, a contour signal is corrected based on a masking effect which is a visual characteristic of an image.