JP2012142755A - Image signal adjustment apparatus and image signal adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress a phenomenon in which a skin color in an image looks like a different color due to psychological complementary color.SOLUTION: An image signal adjustment apparatus 10 comprises: a skin color area detection circuit 11 for detecting a skin color area in an image signal; a skin color area expansion circuit 12 which detects a skin color peripheral area that is the peripheral area of the skin color area detected by the skin color area detection circuit 11; a hue detection circuit 13 which detects the pixels of a predetermined hue, in the skin color peripheral area; an integration circuit 14 which integrates the number of pixels of the predetermined hue detected by the hue detection circuit 13; and an image signal adjustment circuit 15 which when the number of pixels of the predetermined hue integrated by the integration circuit 14 exceeds a predetermined threshold, adjusts the image signal of at least one of the skin color in the skin color area or a predetermined hue in the skin color peripheral area.

Description

  The present invention relates to a video signal adjusting device and a video signal adjusting method for adjusting a video signal.

  With the expansion of the viewing area for digital broadcasting and the rapid spread of high-definition recording media such as digital-compatible receivers and Blu-ray (registered trademark), a high-definition and high-quality viewing environment in ordinary homes is being prepared. Along with this, there is a growing demand for user color adjustment functions for displays.

  Since a liquid crystal display device has a unique color reproduction range and does not match the color reproduction range of video shooting, a liquid crystal display device generally has a color adjustment circuit that adjusts both hues. Many of these color adjustment circuits perform a plurality of color conversions such as correction for skin color or characteristic color.

  Therefore, by detecting the dominant color that has been used most frequently in the entire image, and adjusting the saturation and brightness for the complementary color of the dominant color, color vision can be further improved. There is an image correction apparatus and method that enhances the color contrast and gives the user an image with a better impression than the actual color reproducibility by adding a special effect (see, for example, Patent Document 1).

JP 2009-278227 A

  However, even with such a color adjustment circuit, a psychological hue change to the skin color occurs in particular due to the complementary color due to the increase in the screen size of the liquid crystal display device. For example, if there is a uniform background color that has a skin color complementary color component and high saturation around the human face, a negative afterimage (psychological complementary color based on the background color) appears in accordance with the background color. , It appears to change hue as it mixes with the skin color. As a result, a phenomenon such as dullness of the human face may occur.

  The present invention has been made in view of the above, and it is an object of the present invention to provide a video signal adjustment device and a video signal adjustment method that can effectively suppress a phenomenon in which skin color in a video looks different due to the influence of psychological complementary colors. To do.

  In order to solve the above problems, a first feature of the video signal adjustment device of the present invention is that a skin color area detection unit (11) for detecting a skin color area in a video signal and the skin color area detected by the skin color area detection unit A peripheral region detection unit (12) that detects a skin color peripheral region, a hue detection unit (13) that detects pixels of a predetermined hue in the skin color peripheral region, and the hue detection unit An integration unit (14) that integrates the number of pixels of the predetermined hue, and a skin color of the skin color region or the skin color peripheral region when the number of pixels of the predetermined hue integrated by the integration unit exceeds a predetermined threshold And a video signal adjusting unit (15) for adjusting at least one video signal of the predetermined hue.

  A second feature of the video signal adjusting apparatus according to the present invention is that the hue detector (13) detects a hue having a complementary color relationship with the skin color of the video signal as the predetermined hue.

  According to a third feature of the video signal adjusting device of the present invention, the video signal adjusting unit (15) includes the hue and saturation of the video signal of the predetermined hue in the skin color of the skin color area or the skin color peripheral area. It is to adjust at least one of them.

  According to a fourth aspect of the video signal adjustment device of the present invention, the skin color area video signal detected by the skin color area detection unit (11) and the skin color area adjusted by the video signal adjustment unit (15) are provided. Or the video signal of the skin color peripheral area detected by the peripheral area detection unit (12) and the video signal of the skin color peripheral area adjusted by the video signal adjustment unit (15), An OSD display unit (18) that displays corresponding to the area adjusted by the video signal adjustment unit (15) and displays a button for selecting whether or not to adjust the video signal by the video signal adjustment unit (15). And when the video signal adjustment unit (15) is selected to adjust the video signal, the video signal adjustment unit (15) is adjusted.

  Further, the first feature of the video signal adjustment method of the present invention is a step of detecting a skin color area in the video signal, a step of detecting a skin color peripheral area that is a peripheral area of the skin color area, and the skin color peripheral area, Detecting a pixel of a predetermined hue; integrating the number of pixels of the predetermined hue; and if the number of pixels of the predetermined hue exceeds a predetermined threshold, the skin color of the skin color region or the skin color peripheral region And adjusting the video signal of at least one of the predetermined hues.

  According to a second feature of the video signal adjustment method of the present invention, in the step of detecting pixels of the predetermined hue, a hue having a complementary color relationship with the skin color of the video signal is detected as the predetermined hue. It is in.

  According to a third feature of the video signal adjustment method of the present invention, in the step of adjusting the video signal, the hue and saturation of the video signal of the predetermined hue in the skin color of the skin color area or the skin color peripheral area are selected. It is to adjust at least one of them.

  The fourth feature of the video signal adjustment method of the present invention is that the skin color region video signal and the skin color region video signal adjusted in the step of adjusting the video signal or the skin color peripheral region video signal are adjusted. One of the video signals in the skin tone peripheral area adjusted in the step of adjusting the video signal is OSD-displayed corresponding to the area adjusted in the step of adjusting the video signal, and the video signal is adjusted. A button for selecting whether or not to perform an OSD display, and a step of executing an adjustment when the adjustment of the video signal is selected.

  According to the present invention, it is possible to effectively suppress a phenomenon in which a skin color in an image looks different due to the influence of psychological complementary colors.

It is a figure which shows an example of the hue ring which shows a psychological complementary color. It is a figure which shows the hue change of the skin color when a background color is green. It is a figure which shows the hue change of the skin color when a background color is red. It is a block diagram which shows the structural example of the video signal video signal adjustment apparatus of Embodiment 1 which concerns on this invention. It is explanatory drawing showing the area | region when the UPPER limit (UL) and the LOWER limit (LL) are defined for each of the Y-axis, U-axis, and V-axis according to the first embodiment of the present invention. It is a block diagram which shows the structural example of the skin color area | region detection circuit of Embodiment 1 shown in FIG. (A) to (d), waveforms of Y ′ signal, U ′ signal, V ′ signal output from Y signal limiter, U signal limiter, and V signal limiter shown in FIG. It is a figure which shows an example of a product signal. It is a figure which shows an example of the image information which a skin color area | region detection circuit acquires as a video signal. (A)-(d), respectively, is explanatory drawing which shows an example of the human face in the image information shown in FIG. 9, a skin color area | region, the extension of a skin color area | region, a skin color extended area | region, and a skin color periphery area | region. It is a figure which shows an example of the weighting coefficient in three distance levels from a gravity center. It is a block diagram which shows the example of an internal structure of the integrating circuit of Embodiment 1 shown in FIG. FIG. 2 is a block diagram illustrating an internal configuration example of a video signal adjustment circuit according to the first embodiment illustrated in FIG. 1. It is a block diagram which shows the structural example of the video signal video signal adjustment apparatus of Embodiment 2 which concerns on this invention. 6 is a flowchart illustrating an operation of the video signal processing apparatus according to the second embodiment. It is a figure which shows an example of the OSD information of the skin color detection frame and the background color detection frame which are displayed superimposed on the image according to the second embodiment. It is a figure which shows an example of the OSD information of the skin color automatic correction column in Embodiment 2. It is a figure which shows an example of the OSD information of the background color automatic correction column in Embodiment 2.

  Before describing the embodiments of the video signal adjusting apparatus and the video signal correcting method according to the present invention, first, the influence of the psychological complementary color on the hue will be described.

(About the influence of psychological complementary colors)
For example, when there are two types of skin color background colors, green and red, even if the skin color is the same, if the background color is green, the skin color appears to be “red”. On the other hand, when the background color is red, the skin color appears to be “green”.

  This is a phenomenon caused by the color relative ratio. This is because, when the background color is green, it is affected by magenta, which is a psychological complementary color of green, and when it is red, it is influenced by blue-green, which is a psychological complementary color of red.

  FIG. 1 is a diagram of a hue circle in which psychological complementary color relationships are arranged in pairs.

  If the hue circles are in a mutually complementary relationship, the hue does not change. However, when there is no relationship between the complementary colors of each other, for example, when the skin color is a green background or the skin color is a red background, the hue of the skin color is “reddish” in the direction of the arrows shown in FIGS. It appears to change to “skin color” or “greenish skin color”.

  As for the saturation, even if the skin color is the same, the saturation of the skin color appears to be enhanced on the background color with low saturation. On the other hand, on the background color with high saturation, it seems that the saturation of the skin color is low. This is a phenomenon caused by saturation contrast, and when there is a combination of colors having different saturations, it seems to change so as to emphasize the difference in saturation between each other.

  Therefore, in the embodiments of the video signal adjustment device and the video signal correction method according to the present invention, “reddish skin color”, “greenish skin color”, or “highly saturated skin color” due to the influence of psychological complementary color as described above. '' Or `` Saturated skin color '' or other color relative ratio or saturation contrast, the influence of the color relative ratio or saturation contrast on at least one of the hue or saturation of each of the background color or skin color. By shifting to the optimum hue and saturation so as to cancel out, a scene in which the skin color such as the face color looks bad is avoided.

  Further, in the embodiment of the video signal adjustment apparatus and the video signal correction method according to the present invention, for the conversion between the hue and saturation of the skin color, the video that attracts attention from the face, the video that occurs at short intervals, etc. Considering the possibility of giving the viewer a sense of incongruity, it is also possible to perform hue or saturation conversion processing only on the background color, not on the skin color.

  The embodiment of the video signal adjusting device and the video signal correcting method according to the present invention uses not only the skin color but also any color as the color for which the hue or saturation contrast phenomenon is to be suppressed, and information on the color is used. If specified, color conversion can be performed by shifting to the optimum hue or saturation so as to cancel the influence of hue or saturation contrast using the same method.

(Description of Video Signal Adjustment Device and Video Signal Correction Method of Embodiment 1)
Next, Embodiment 1 of the video signal adjusting device and the video signal correcting method according to the present invention will be described.

  Here, the video signal adjusting device includes a video signal display device provided with a display and a monitor, a hard disk, a DVD, and a Blu-ray disc that are not provided with a display and a monitor and are connected to the display and the monitor. Including high-definition recording media recording / playback devices, and imaging devices such as digital cameras and camcorders with which a small liquid crystal display device is integrated or attached.

  FIG. 4 is a block diagram showing a configuration example of Embodiment 1 of the video signal adjustment device according to the present invention.

  As shown in FIG. 4, the video signal adjustment device 10 according to the first embodiment includes a flesh color area detection circuit 11, a flesh color area expansion circuit 12, a hue detection circuit 13, an integration circuit 14, a video signal adjustment circuit 15, A first delay device 16 and a second delay device 17 are provided. The video signal adjustment device 10 corrects or adjusts the skin color or background color of the video signal S1 such as a primary color signal (RGB signal) obtained by decoding a TV signal or the like, or an RGB signal of a personal computer (PC).

  Next, the operation of the video signal adjustment apparatus 10 will be briefly described.

  First, the skin color area detection circuit 11 receives the video signal S1 and outputs a skin color area signal S2 indicating a skin color area, which is a skin color area, to the skin color area expansion circuit 12. The video signal S1 is, for example, a YUV signal or an RGB signal.

  The flesh color area expansion circuit 12 detects a flesh color expansion area including the flesh color area based on the flesh color area signal S2 indicating the flesh color area output from the flesh color area detection circuit 11 in order to obtain an area that has a complementary color effect on the flesh color. A skin color peripheral region signal S3 indicating a region around the skin color region (hereinafter referred to as a skin color peripheral region) is output to the hue detection circuit 13 from the skin color region and the skin color extension region. The skin color extended region may be a region that includes the skin color region and has a larger area than the skin color region, and may have a region extended from the skin color region around the skin color region.

  The hue detection circuit 13 receives the flesh color peripheral area signal S3 output from the flesh color area expansion circuit 12, and based on the flesh color peripheral area signal S3, a specific relationship mainly with the flesh color in the flesh color peripheral area of the video signal S1, that is, Hue that is in the complementary color relationship is detected. For this reason, the hue detection circuit 13 is set or stored in advance with specific hue information to be detected so that a hue having a complementary color relationship with the skin color can be detected.

  Here, it is desirable that the hue information has a central hue and a width of the hue. Further, as the color space indicating the hue, it is desirable to use a YUV signal that can handle the hue information separately on the UV axis, rather than an RGB signal including luminance information. The conversion from RGB signals to YUV signals is performed by ITU-R BT. Follow the 601 standard. ITU-R BT. In the 601 standard, the relationship between the YUV signal and the RGB signal is defined by the following formula (1).

Y = 0.299 × R + 0.587 × G + 0.114 × B
U = −0.168 × R−0.331 × G + 0.500 × B (1)
V = 0.500 × R−0.419 × G−0.081 × B
The hue detection circuit 13 outputs a detection signal S4 to the integration circuit 14 when detecting color information within the range of the hue information in accordance with the hue information to be detected set in advance. That is, when the hue detection circuit 13 detects a pixel having hue information mainly in a complementary color relationship with the skin color in the skin color peripheral region based on the skin color peripheral region signal S3 and the video signal S1, The detection signal S4 is output to the integrating circuit 14. The hue detection circuit 13 can also set a plurality of hue information and detect pixels corresponding to each hue information. At this time, the detection signal S4 is output to the integration circuit 14 by the number (n) of the set hue information (S41 to S4n).

  The integration circuit 14 integrates the number of pixels of a specific hue in the skin color peripheral area detected by the hue detection circuit 13, that is, a hue having a color-catching relationship with the skin color in this embodiment. Specifically, the integrating circuit 14 performs the presence / absence and quantitative determination of a predetermined hue signal having a color-catching relationship with the skin color in the skin color peripheral region based on the detection signal S4 output from the hue detection circuit 13. For example, the number of pixels of a predetermined hue in the skin color peripheral region is integrated within one screen by the number of times the detection signal S4 is input, and it is determined whether or not the integrated value of the number of pixels exceeds a predetermined threshold. When the integrated value of the number of pixels exceeds a predetermined threshold value, an integrated value signal S5 is output to the video signal adjustment circuit 15.

  The video signal adjustment circuit 15 adjusts a video signal of a predetermined hue in the skin color of the skin color area or the skin color peripheral area. Specifically, when the integrated value signal S5 is sent from the integrating circuit 14, the video signal adjusting circuit 15 adjusts or corrects the hue of the video signal having a predetermined hue in the flesh color in the flesh color area or in the flesh color peripheral area. Processing is performed and output as an output video signal S6. This hue adjustment process is performed in units of one frame. Whether the video signal adjustment circuit 15 adjusts the video signal in the skin color area or the skin color peripheral area may be determined in advance.

  Note that the output format of the video signal adjustment circuit 15 is converted into an RGB signal when the hue adjustment (correction) processing is performed with a YUV signal, and is set as an output video signal S6. The video signal S1 input to the video signal adjustment apparatus 10 is processed in the same way when handling not only RGB signals but also YUV signals. In this case, the skin color area detection circuit 11 in the foremost stage does not need to convert RGB signals into YUV signals, and the video signal adjustment circuit 15 in the last stage converts the YUV signals into RGB signals and outputs the output video signal S6. Output as.

  In the first embodiment, the number of hue axes to be set is not limited for the hue set by the hue detection circuit 13.

  In the first embodiment, the first delay unit 16 is provided to adjust the time for performing the processing in the flesh color area detection circuit 11 and the flesh color area expansion circuit 12, and the hue detection circuit 13 and the integration circuit 14 The second delay unit 17 is provided for time adjustment in performing the above process.

  Next, a detailed configuration and an operation example of each component constituting the video signal adjustment device 10 of FIG. 4 will be described.

(Details of Configuration and Operation of Skin Color Area Detection Circuit 11)
As described above, the flesh color area detection circuit 11 detects a flesh color area component indicating a specific flesh color from the input video signal S1 (YUV signal), and outputs a flesh color area signal as a signal indicating the flesh color area having the flesh color area component. S2 is output. At this time, the flesh color area detection circuit 11 provides a certain hue width centering on the flesh color and detects the flesh color vicinity color.

  That is, when detecting the skin color region detection circuit 11 including the neighboring colors of the skin color, for example, as shown in FIG. 5, the upper limit value (UL; UPPER limit) is set for each of the Y axis, the U axis, and the V axis. ) And lower limit value (LL; LOWER limit), Y axis upper limit value YUL, Y axis lower limit value YLL, U axis upper limit value UUL, U axis lower limit value ULL, V axis upper limit value VUL, and V axis lower limit value VLL are determined. .

  FIG. 6 is a block diagram illustrating a configuration example of the flesh color area detection circuit 11.

  In FIG. 6, the skin color area detection circuit 11 includes an RGB / YUV conversion circuit 111, a Y signal limiter 112, a U signal limiter 113, and a V signal limiter 114. When a YUV signal is input as the video signal S1, the RGB / YUV conversion circuit 111 can be omitted.

  Here, the Y signal limiter 112, the U signal limiter 113, and the V signal limiter 114 are respectively shown in the block diagram of FIG. 6 when the region defined by the limit values x and y is the limit function LM (x, y). As shown, limit processing is performed by LM (YLL, YUL) for the Y axis, LM (ULL, UUL) for the U axis, and LM (VLL, VUL) for the V axis. That is, each of the detected values of Y, U, and V is compared with a specific threshold value (limit function LM) for each of Y, U, and V. For example, if the detected value is greater than or equal to a specific threshold value, “1” is assigned. If it is smaller than the threshold, “0” is assigned and output as Y ′, U ′, V ′, respectively. As a result, the flesh color area detection circuit 11 can detect the flesh color and the flesh color neighborhood color having a width near the flesh color by the limit function LM (x, y).

  7A to 7D show the waveform of the Y ′ signal output from the Y signal limiter 112, the waveform of the U ′ signal output from the U signal limiter 113, and the waveform output from the V signal limiter 114, respectively. It is a figure which shows an example of the waveform of a V 'signal, and the AND signal of a Y' signal, a U 'signal, and a V' signal.

  The logical product signal of the Y ′ signal, U ′ signal, and V ′ signal shown in FIG. 7D is represented by the following mathematical formula (2).

LM (YLL, YUL) & LM (ULL, UUL) & LM (VLL, VUL) (2)
In formula (2), “&” indicates a logical product.

  As described above, the skin color area detection circuit 11 can detect a skin color area within a specific range.

(Detailed operation of the skin color area expansion circuit 12)
Usually, when the skin color is seen in the video signal, the human face color occupies the majority.

  For example, when the skin color area detection circuit 11 acquires an image 91 as shown in FIG. 8 as the video signal S1, for example, first, a known face recognition technique such as luminance detection or facial feature recognition is used as shown in FIG. As shown in a), a human face or face area is detected. Next, the flesh color area detection circuit 11 detects the flesh color area A of the person's face from the luminance, hue, and the like as shown in FIG. 9B, and outputs the flesh color area signal S2 to the flesh color area expansion circuit 12.

  When the flesh color area detection circuit 11 receives the flesh color area signal S2, the flesh color area expansion circuit 12 expands the flesh color area A by a predetermined range as shown in FIG. A skin color expansion region B as shown is generated. In this embodiment, it is set as the skin color expansion | extension area | region B which extended the area | region concentrically centering on the skin color area | region A.

  Here, the skin color region A is included in the skin color extension region B⊃skin color region A, that is, the skin color extension region B. Therefore, the skin color area expansion circuit 12 can obtain the skin color peripheral area C as shown in FIG. 9E by subtracting the skin color area A from the skin color expansion area B.

  Next, two detection examples of the skin color peripheral region C in the skin color region expansion circuit 12 are given below.

(First detection example of skin color peripheral region C)
In the first detection example, the skin color region expansion circuit 12 performs LPF as a process for region expansion on the logical product signal “1” of the Y ′ signal, the U ′ signal, and the V ′ signal shown in FIG. (Low Pass Filter).

  Various configurations of this LPF can be considered, but the following method will be described as an example. Since the values of the normal U signal and V signal become extremely small due to the LPF processing, the weighting processing is performed before the LPF processing.

  That is, the flesh color region expansion circuit 12 multiplies the logical product signal “1” of the Y ′ signal, U ′ signal, and V ′ signal shown in FIG. 7D by a weighting coefficient M (M is greater than 1). Thereafter, LPF processing is performed, and thereafter, threshold value processing, that is, “1” is assigned when the threshold value is larger than a specific threshold value, and “0” is assigned otherwise, thereby obtaining a region signal. The skin color area expansion circuit 12 sets a skin color expansion area B obtained by extending the skin color area A as shown in FIG. 9 and a skin color peripheral area C obtained by removing the skin color area A from the skin color expansion area B as shown in FIG. Can be generated.

  Here, in order to expand the flesh-color area A and set the flesh-color expansion area B, it is necessary to increase the order of the LPF, and it is desirable to apply a high-order LPF in the horizontal and vertical directions. However, when a face as shown in FIG. 9B is detected as the skin color area A from the image 91 as shown in FIG. 8, the background image is adjacent to the left and right areas of the skin color area A, and is adjacent in the upward direction. There is a high possibility that an image of hair or a hat is present in the region to be worn, and an image of clothing or the like is present in the region adjacent downward. For this reason, in the skin color peripheral area C, it is rare that the skin color area A has a color having the same hue as the skin color in the vertical direction (vertical direction). Therefore, in the skin color peripheral region C, the skin color is affected as a psychological complementary color by a color of a certain hue in a region horizontally aligned with the cheeks and forehead, that is, a background region adjacent to the skin color region A in the left-right direction. This is a case that exists continuously.

  Further, applying a high-order LPF in the vertical direction of the screen requires a lot of hardware such as a memory.

  For this reason, the flesh color region expansion circuit 12 can use only the horizontal direction processing for the LPF for region expansion and omit the memory necessary for the LPF processing in the vertical direction.

  The flesh color area expansion circuit 12 obtains a flesh color peripheral area C that is a peripheral area of the flesh color area A from the flesh color area A by the above-described method, and uses the flesh color peripheral area signal S3 indicating the flesh color peripheral area C as a hue detection circuit 13. Output to.

(Second detection example of skin color peripheral region C)
The skin color area expansion circuit 12 outputs a skin color peripheral area signal S3 to the hue detection circuit 13, and the hue detection circuit 13 calculates a hue signal S41 based on the skin color peripheral area signal S3. At that time, the hue detection circuit 13 may weight the hue signal S41 depending on the distance from the center of gravity of the skin color region A. This is because even when there is a psychological complementary color in the skin color peripheral area C, there is a case where a psychological complementary color exists in an area in contact with the outermost periphery of the skin color area A in the skin color peripheral area C and an area near the outermost periphery of the skin color peripheral area C, The influence of the psychological complementary color on the skin color area A differs from the case where the psychological complementary color exists in the area farthest from the area A. Of the skin color peripheral region C, the region closer to the skin color region A has the greatest influence of the psychological complementary color on the skin color region A, and the effect decreases as the distance from the skin color region A increases.

  Therefore, the hue detection circuit 13 calculates the center of gravity in the skin color region A, determines several points from the center of gravity to the boundary (outermost circumference) between the skin color region A and the skin color peripheral region C, and calculates the distance from the center of gravity. Then, they are threshold-processed, and levels are provided and classified as short distance a, medium distance b, and long distance c.

  FIG. 10 is a diagram illustrating an example of a weighting coefficient depending on the distance from the center of gravity of the flesh color region A, in which the hue detection circuit 13 weights the hue signal S41.

  In this embodiment, as shown in FIG. 10, the weighting coefficient is reduced as the distance from the center of gravity increases. That is, the weighting coefficient for the short distance a is set to the largest. Here, as an example, weighting coefficients at three distances, short distance a, medium distance b, and long distance c, are set as an example. However, as the most general method, weighting is performed using a linear function or the like for the distance. A technique for calculating a coefficient may be used. In any case, the method is not limited as long as the above characteristic that the weighting coefficient decreases as the distance from the center of gravity increases is satisfied. The distance from the center of gravity is preferably handled in the horizontal and vertical directions, but as described in the first detection example of the skin color peripheral region C, colors that affect the skin color as a psychological complementary color are cheeks and foreheads. Since there are many cases where the background regions are arranged in the horizontal direction, the distance in the horizontal direction alone may be selected and the weighting coefficient may be calculated.

  The detection method of the skin color area A, the skin color extension area B, and the skin color peripheral area C is not limited to the above-described method, and may be detected by a known technique. For example, the skin color and face area may be extracted using a human body area extraction method described in Japanese Patent Application Laid-Open No. 2008-15641 (name of invention “human body area extraction method and apparatus and program”).

(Detailed operation of the hue detection circuit 13)
In the hue detection circuit 13, the video signal S1 that has passed through the first delay device 16 is converted from an RGB signal to a YUV signal, if necessary, in the same manner as in the skin color area detection circuit 11, and then has a complementary color relationship mainly with the skin color. Specific hue information (Y, U, V) to be detected is set in advance so that a certain hue can be detected. It is desirable that this hue information has a central hue and its hue width in the same manner as when the flesh color hue range is extracted. Here, as an example, two types of hue axis 1 and hue axis 2 are set and each has a hue range, but the number of hue axes to be set is not limited. In the hue detection circuit 13, in the hue axis 1 and the hue axis 2, the upper limit value (UL) and the lower limit value (LL) are respectively shown in the Y axis, the U axis, and the V axis as shown in FIG. And the limiter processing described with reference to FIG. 6 is performed.

  When detecting the video signal having the set hue information, the hue detection circuit 13 outputs a detection signal S4 indicating that the pixel having the hue to be detected has been detected to the integration circuit. This makes it possible to determine whether or not there is a combination of Y, U, and V that are complementary to the skin color in the skin color peripheral area. In the present embodiment, pixels of a predetermined hue (complementary color) in the skin color peripheral area C are detected by the hue detection circuit 13, but pixels of a predetermined hue may be detected from the skin color expansion area B. At that time, the flesh color area expansion circuit 12 may supply a signal indicating the flesh color expansion area B to the hue detection circuit 13.

(Detailed operation of integrating circuit 14)
When the detection signal S4 is input from the hue detection circuit 13, the integration circuit 14 integrates the detection signal S4 and outputs an integrated value signal S5 based on the integrated detection signal S4 to the video signal adjustment circuit 15.

  When the integration value signal S5 is input from the integration circuit 14, the video signal adjustment circuit 15 is input with the time adjusted via the first delay device 16 and the second delay device 17 in accordance with the integration value signal S5. At least one of the hue and saturation of the video signal S1 is adjusted and output as the output video signal S6.

  FIG. 11 is a block diagram illustrating a configuration example of the integrating circuit 14.

  In FIG. 11, the integrating circuit 14 includes a selector 141, an adder 142, a limiter 143, and a divider 144.

  In the integrating circuit 14, for example, the selector 141 outputs an integrated value obtained by integrating the detection signal S4 from the hue detecting circuit 13 within one screen. When “1” is input as the detection signal S4, the selector 141 outputs the detection signal S4 to the adder 142. Note that the adder 142 resets the integration result in response to the input of the reset signal R.

  When the detection signal S4 is “1”, it indicates that a pixel of a specific hue (skin color complementary color) exists in the skin color peripheral area C.

  In the adder 142, a value obtained by adding the detection signal S4 is output to the limiter 143, and simultaneously input to the adder 142 and then added to the input detection signal S4. Note that if the addition result reaches a certain size or more, it is not necessary any more, so in the example of the integration circuit 14 shown in FIG. The integrated value indicating the number of pixels of a predetermined hue in the skin color peripheral area C thus obtained is normally adjusted in amplitude by the divider 144 and output as an integrated value signal S5. Here, simply, the divider 144 adjusts the amplitude by truncating the lower part of the bit length indicating the integrated value signal S5. The integration in the adder 142 is performed in units corresponding to one frame of the video signal S1 input to the video signal adjustment device 10 or the video signal S6 output from the video signal adjustment device 10. Therefore, it is necessary to reset the adder 142 once to “0” for each frame, and this is performed by the reset signal R.

  Note that the reset signal R does not need to be input every frame, and may be input once in a plurality of frames in the case of a configuration that requires time for calculation. This is because psychological complementary color is a psychological effect and has a cognitive period longer than the period of one frame. In this example, for convenience of explanation, the unit is one frame. Through the above processing, the integrating circuit 14 generates an integrated value signal S5 that is a control signal for performing video signal adjustment, and outputs the integrated value signal S5 to the video signal adjusting circuit 15. When a plurality of complementary hue axes are set, the integrated value signal S5 is generated for each hue axis by a similar circuit.

(Detailed configuration and operation of video signal adjustment circuit 15)
FIG. 12 is a block diagram illustrating a configuration example of the video signal adjustment circuit 15.

  In FIG. 12, the video signal adjustment circuit 15 includes a correction amount setting unit 151 and a hue / saturation correction processing unit 152. The correction value setting unit 151 receives the integrated value signal S <b> 5 from the integrating circuit 14. When the integration circuit 14 generates integration value signals S51 and S52 for the hue axis 1 and the hue axis 2, the integration value signals S51 and S52 are input to the correction amount setting unit 151.

  In the correction amount setting unit 151, correction amounts of hue and saturation with respect to the integrated value are set in advance for each hue axis. Accordingly, when the integrated value signals S51 and S52 for the hue axes 1 and 2 are input to the correction amount setting unit 151, the correction amount signals for the hue and saturation depending on the magnitudes of the integrated value signals S51 and S52. The hue correction amount signal S511 of the hue axis 1, the saturation correction amount signal S512 of the hue axis 1, the hue correction amount signal S521 of the hue axis 2, and the saturation correction amount signal S522 of the hue axis 2 are hue / saturation correction. The data is output to the processing unit 152. Here, since the correction amount setting unit 151 requires adjustment while watching an actual video, a lookup table that can be easily changed may be used.

  The hue / saturation correction processing unit 152 detects the hue and saturation for each hue axis with respect to the YUV signal of the input video signal S1 in order to control the hue or saturation of the input video signal S1. At least one of the saturation is corrected. The hue / saturation correction processing unit 152 of the present embodiment receives the input video signal S1 as an RGB signal, and converts the RGB signal into a YUV signal by an RGB / YUV conversion circuit (not shown).

  Here, the hue / saturation correction processing unit 152 of the first embodiment detects the hue and saturation for each hue axis for the skin color of the skin color region A in the input video signal S1, and out of the hue and saturation. By performing at least one of the correction processes, a phenomenon in which the skin color of the skin color area A looks different due to the influence of the psychological complementary color due to the background color of the skin color peripheral area C may be suppressed, or the input video signal S1 Of these, the background color of the skin color peripheral region C is detected by detecting the hue and saturation for each hue axis, and performing correction processing of at least one of the hue and saturation, so that the skin color differs due to the influence of the psychological complementary color by the background color. You may make it suppress the phenomenon seen in a color.

  As described above, the skin color area A of the skin color vicinity color is detected by detecting the skin color vicinity color, and the skin color peripheral area C excluding the skin color area A by expanding the skin color area A is detected. It is possible to solve the problem of the complementary color that the skin color in the skin color region A or the skin color near the skin color looks different due to the influence of the background color.

  The details of the video signal adjustment circuit 15 are described in, for example, Japanese Patent Application Laid-Open No. 2007-49341 (name of invention “video correction device”). In particular, the color correction circuit shown in FIG. It can be used as a reference. Similar to the video signal adjustment circuit 15 necessary for the configuration in the first embodiment, this color correction circuit is configured to be able to adjust independent hue and saturation with a plurality of hue axes. The hue 2 (p2) input to the correction coefficient calculation unit 3n in the color correction circuit shown in FIG. 6 of Japanese Patent Application Laid-Open No. 2007-49341 and the hue corresponding to the saturation s are the hues in FIG. 12 of the first embodiment. Since the correction amount signals S511 and S521 and the saturation correction amount signals S512 and S522, the video signal adjustment circuit 15 according to the present invention processes them in the same manner as the color correction apparatus described in Japanese Patent Application Laid-Open No. 2007-49341. Thus, the hue and saturation can be corrected.

  Then, the video signal adjustment circuit 15 obtains the Y′U′V ′ signal of the output video signal S6, which is the corrected video signal, as a result of correcting the hue and saturation of the YUV signal of the input video signal S1. As for the output format of the video signal adjustment circuit 15, since the above processing is performed on the YUV signal, the Y′U′V ′ signal is subjected to matrix conversion by an RGB / YUV conversion circuit (not shown) into an RGB signal. , R′G′B ′ signal is an output video signal S6.

  As described above, the video signal adjustment apparatus 10 according to the first embodiment expands the skin color area in the video signal by a predetermined range to detect the skin color area peripheral area, and specifies the skin color of the video signal in the skin color peripheral area. A specific hue having a relationship is detected, the number of pixels of a specific hue having a complementary color relationship with the skin color is integrated, and the video signal of the skin color region or the skin color peripheral region is adjusted based on the integrated value of the number of pixels. Accordingly, it is possible to effectively suppress a phenomenon in which the skin color of the skin color region appears to be different due to the influence of the psychological complementary color due to the background color of the skin color peripheral region in the video.

(Embodiment 2)
In the first embodiment, in order to solve the problem of the complementary color that the skin color of the skin color area looks different due to the influence of the background color of the skin color peripheral area, the hue or saturation of the skin color of the skin color area or the background color of the skin color peripheral area is solved. The video signal adjusting apparatus according to the second embodiment has been described as automatically adjusting at least one of them, but the on-screen adjustment result of the hue or saturation of the video signal of the skin color of the skin color area or the background color of the skin color peripheral area is displayed on the screen. By displaying on the display (OSD), it can be confirmed as a simulation, and the user can adjust the correction level of hue and saturation. In addition, the user can determine whether or not to perform the hue and saturation correction processes by looking at the simulation results by OSD display.

(Configuration of video signal adjusting apparatus according to Embodiment 2)
FIG. 13 is a block diagram illustrating a configuration example of the video signal adjustment apparatus according to the second embodiment.

  In FIG. 13, the video signal adjustment device 10 </ b> A according to the second embodiment is obtained by providing a new OSD display circuit 18 with respect to the video signal adjustment device 10 shown in FIG. 4. This is the same as the video signal adjustment device 10. Therefore, in FIG. 13, the same components as those of the video signal adjustment device 10 of FIG.

  The OSD display circuit 18 performs the operation shown in FIG. 14, the video signal of the flesh color of the flesh color area after adjustment by the video signal adjustment circuit 15 or the background color of the flesh color peripheral area, and the flesh color or flesh color periphery of the flesh color area before adjustment An OSD display of the background background video signal and OSD display of an ON / OFF button or the like for selecting whether or not to perform adjustment are performed. The OSD display circuit 18 receives the skin color area signal S2 from the skin color area detection circuit 11, receives the skin color peripheral area signal S3 from the skin color area expansion circuit 12, and performs OSD display based on each.

(Operation of the video signal adjusting apparatus of the second embodiment)
Next, the operation of the video signal adjustment apparatus 10A will be described.

  FIG. 14 is a flowchart showing the operation of the video signal adjustment apparatus 10A.

  First, in the video signal adjusting apparatus 10A, as in the first embodiment, a video signal is acquired (step S1600), and then the skin color area A or the skin color peripheral area C is recognized (step S1610).

  Next, the OSD display circuit 18 performs a skin color detection frame 171 indicating a skin color area A and a background color detection frame 172 indicating a skin color peripheral area C on the display image 91 by OSD superimposition processing, for example, as shown in FIG. OSD display is performed, and marking processing is performed on the display image 91 (step S1620).

  FIG. 15 shows an example of OSD information displayed on the image by the video signal adjustment apparatus 10A. In the second embodiment, the flesh color area expansion circuit 12 defines the flesh color peripheral area C as the peripheral area expanded in the horizontal direction with respect to the flesh color area A for the reason described above.

  Next, the OSD display circuit 18 displays the OSD information in the skin color automatic correction column 180 as shown in FIG. 16 and the OSD information in the background color automatic correction column 190 as shown in FIG. Then, the skin color or background color before correction is OSD-displayed in the OSD information of the skin color automatic correction column 180 and the background color automatic correction column 190 (step S1630). Note that the OSD information of either the skin color automatic correction column 180 or the background color automatic correction column 190 may be displayed corresponding to the region (skin color region or skin color peripheral region) adjusted by the video signal adjustment circuit 15. The OSD information is displayed superimposed on a part or the whole of the image 91.

  FIG. 16 shows an example of the OSD information in the skin color automatic correction column 180 displayed by the processing in step S1630 when the video signal adjustment circuit 15 adjusts the skin color of the skin color region.

  As shown in FIG. 16, the OSD information in the skin color automatic correction field 180 includes an ON / OFF button 181 for selecting skin color automatic correction, and a hue adjustment bar 182 for manually adjusting the hue and saturation of the skin color. The image includes a saturation adjustment bar 183, a pre-processing window 184 that displays the pre-processing and post-processing states when the skin color is automatically or manually adjusted, and a post-processing window 185.

  Therefore, when the skin color is adjusted, the skin color before correction is displayed in the pre-processing window 184 of the skin color automatic correction column 180 by the processing of step S1630. In step S1630, since the adjustment by the video signal adjustment circuit 15 is not performed, nothing is displayed in the post-processing window 185, or the skin color automatic correction column 180 where the post-processing window 185 is not displayed is displayed. That's fine.

  FIG. 17 shows an example of the OSD information in the background color automatic correction column 190 displayed by the processing in step S1630 when the video signal adjustment circuit 15 adjusts a predetermined hue in the skin color peripheral area. In the present embodiment, a predetermined hue included in the skin color peripheral area detected by the hue detection circuit 13 is set as a background color adjusted by the video signal adjustment circuit 15.

  The OSD information in the automatic background color correction column 190 shown in FIG. 17 also has an ON / OFF button 191 for selecting automatic background color correction and the background color as in the OSD information in the automatic skin color correction column 180 shown in FIG. A hue adjustment bar 192 for manually adjusting the hue and saturation, a saturation adjustment bar 193, a pre-processing window 194 for displaying the pre-processing and post-processing states when the background color is automatically or manually adjusted, An image with the post-processing window 195 is included.

  Therefore, when the background color is adjusted, the background color before correction is displayed in the pre-processing window 194 of the background color automatic correction column 190 by the processing of step S1630.

  Here, the video signal adjustment device 10A executes the adjustment of the skin color in the skin color region A or the background color in the skin color peripheral region C, that is, the correction process, similarly to the video signal adjustment device 10 of the first embodiment (step S1640). .

  Next, the OSD display circuit 18 OSD superimposes the corrected skin color or background color on the post-processing window 185 in the OSD information in the skin color automatic correction column 180 or the post-processing window 195 in the OSD information in the background color automatic correction column 190. It is displayed (step S1650). The OSD display circuit 18 displays the skin color before correction in the pre-processing window 184 and the skin color after correction in the post-processing window 185 in the OSD information of the skin color automatic correction column 180. In the OSD information in the background color automatic correction column 190, the pre-processing and post-processing background colors are OSD superimposed on the pre-processing window 194 and the post-processing window 195.

  At that time, in the video signal adjustment apparatus 10A, the user can adjust the hue adjustment bar 182 and the saturation adjustment bar 183 in the OSD information in the skin color automatic correction column 180 shown in FIG. 16 or the OSD in the background color automatic correction column 190 shown in FIG. By manually operating the hue adjustment bar 192 and the saturation adjustment bar 193 in the information, the user refers to the skin color or background color before and after processing, and the hue in the skin color or background color corrected by the processing in step S1640 Alternatively, the saturation may be further manually adjusted (step S1660). Note that the process of step S1660 is a manual operation process by the user, and may be omitted if not necessary or may be performed before step S1650.

  The user confirms the color after correction displayed in the post-processing window 185 or the post-processing window 195, and the ON / OFF button 181 in the OSD information in the skin color automatic correction column 180 or the OSD information in the background color automatic correction column 190. It is possible to select whether to perform image adjustment (ON) or not (OFF) as if it was manually adjusted with the ON / OFF button 191. The video signal adjustment device 10A receives the selection operation by the user (step S1670). The video signal adjustment device 10A determines whether or not ON is selected in step S1670 (step S1680). The signal indicating the selection operation by the user may be received by the OSD display circuit 18 or the video signal adjustment circuit 15. When the OSD display circuit 18 receives a signal indicating a selection operation, the OSD display circuit 18 may supply a signal indicating the selection operation to the video signal adjustment circuit 15, and the video signal adjustment circuit 15 receives a signal indicating the selection operation. Based on this, the steps after step S1670 are processed.

  When ON is selected (step S1680 “YES”), the video signal adjustment circuit 15 of the video signal adjustment device 10A is similar to the video signal adjustment circuit 15 of the first embodiment, and the skin color or skin color of the skin color region A in the image 91 is displayed. Correction processing is executed for the background color of the peripheral area C (step S1690).

  On the other hand, when OFF is selected (step S1680 “NO”), the video signal adjustment circuit 15 resets the skin color or background color adjustment processing (step S1700).

  As described above, in the video signal adjustment apparatus 10A of the second embodiment, before applying the adjustment result of the skin color of the skin color area or the background color of the skin color peripheral area by the same adjustment processing as that of the first embodiment to the display image. The OSD is displayed on the display image. Thereby, the user can confirm beforehand the adjustment result of the skin color or background color in a display image as a simulation result by referring to the OSD display. As a result, the user can determine whether or not to perform the skin color or background color correction processing after seeing the simulation results by the OSD display, which improves the convenience for the user.

  In the description of the first and second embodiments, the video signal adjustment devices 10 and 10A are configured by hardware as shown in FIGS. 4 and 13, but the present invention is not limited to this, and the CPU Of course, it may be configured to execute the functions of the video signal adjustment apparatuses 10 and 10A shown in FIGS.

  In the first and second embodiments, the description is limited to skin color detection. However, the video signal adjustment device of the present invention is not limited to detecting a skin color image and adjusting a skin color region or a region in the vicinity thereof. . A circuit for detecting a predetermined color area is provided in place of the flesh color area detection circuit 11, and the hue detection circuit 13 detects the hue of a color complementary to the predetermined color, thereby adjusting the predetermined color in the same manner. Can be done.

  Further, the skin color area detection circuit 11 may detect a plurality of skin colors. The skin color area extension circuit 12 may set a skin color extension area for each detected skin color area to obtain a skin color peripheral area, and the hue detection circuit 13 may detect a complementary color for each skin color. Alternatively, a plurality of flesh colors can be detected by providing a circuit having a set of flesh color area detection circuit 11 and flesh color area expansion circuit 12 as many as the number of colors to be detected. It is also possible to detect a plurality of different color areas and their peripheral areas with the same configuration. Further, when a plurality of persons are included in the video, the skin color area detection circuit 11 may detect a plurality of skin color areas included in the video.

11. Skin color area detection circuit (skin color area detection unit)
12 Skin color area expansion circuit (peripheral area detector)
13 Hue detection circuit (Hue detection unit)
14 Integration circuit (integration unit)
15 Video signal adjustment circuit (Video signal adjustment unit)
16, 17 delay unit 18 OSD display circuit (OSD display unit)

Claims (8)

A skin color area detection unit for detecting a skin color area in the video signal;
A peripheral region detection unit that detects a skin color peripheral region that is a peripheral region of the skin color region detected by the skin color region detection unit;
A hue detection unit that detects pixels of a predetermined hue in the skin color peripheral area;
An integration unit for integrating the number of pixels of the predetermined hue detected by the hue detection unit;
Video signal adjustment for adjusting at least one video signal of the predetermined hue in the skin color of the skin color area or the skin color peripheral area when the number of pixels of the predetermined hue integrated by the integration unit exceeds a predetermined threshold And
A video signal adjusting apparatus comprising: The hue detection unit is
Detecting a hue complementary to the skin color of the video signal as the predetermined hue;
The video signal adjusting apparatus according to claim 1, wherein The video signal adjustment unit
Adjusting at least one of the hue and saturation of the video signal of the predetermined hue of the skin color of the skin color area or the peripheral area of the skin color;
3. The video signal adjusting apparatus according to claim 1, wherein the video signal adjusting apparatus is a video signal adjusting apparatus. A video signal of the skin color area detected by the skin color area detection unit and a video signal of the skin color area adjusted by the video signal adjustment unit, or a video signal of the skin color peripheral area detected by the peripheral region detection unit Either one of the video signals in the skin tone peripheral region adjusted by the video signal adjustment unit is displayed corresponding to the region adjusted by the video signal adjustment unit, and the video signal is adjusted by the video signal adjustment unit. An OSD display unit for displaying a button for selecting whether or not
When the video signal adjustment unit is selected to adjust the video signal, the video signal adjustment unit is adjusted.
The video signal adjusting device according to claim 1, wherein the video signal adjusting device is a video signal adjusting device. Detecting a skin color area in the video signal;
Detecting a skin color peripheral region that is a peripheral region of the skin color region;
Detecting pixels of a predetermined hue in the skin color peripheral area;
Integrating the number of pixels of the predetermined hue;
Adjusting the video signal of at least one of the predetermined hue in the skin color of the skin color area or the skin color peripheral area when the number of pixels of the predetermined hue exceeds a predetermined threshold;
A video signal adjustment method comprising: In the step of detecting pixels of the predetermined hue,
Detecting a hue complementary to the skin color of the video signal as the predetermined hue;
6. The video signal adjusting method according to claim 5, wherein In the step of adjusting the video signal,
Adjusting at least one of the hue and saturation of the video signal of the predetermined hue of the skin color of the skin color area or the peripheral area of the skin color;
7. The video signal adjustment method according to claim 5, wherein the video signal adjustment method is performed. The flesh color region image signal and the flesh color region image signal adjusted in the step of adjusting the image signal, or the flesh color region image signal and the image signal in the step of adjusting the image signal. One of the video signals is displayed in an OSD corresponding to the area adjusted in the step of adjusting the video signal, and a button for selecting whether to adjust the video signal is displayed in the OSD;
Further comprising the step of performing the adjustment when the adjustment of the video signal is selected.
The video signal adjustment method according to claim 5, wherein the video signal adjustment method is a video signal adjustment method.

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