JP2006166337A - Skin detail circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a skin detail circuit which prevents wrinkles, a rough skin, spots and the like of a human figure from being conspicuous in both zooming-up and zooming-back and avoids degradation of a resolution of a flesh-colored part in the case of zooming-back. <P>SOLUTION: A flesh-colored area detection circuit 8 counts the number of flesh-colored parts from R, G and B signals for the unit of a single pixel or for the unit of multiple pixels, detects a flesh-colored area from the counted number, outputs a signal regarding the flesh-colored area to a skin DTL gain control unit 9 and outputs a signal regarding whether it is a flesh-colored part to a DTL signal multiplication unit 10. The skin DTL gain control unit 9 calculates a ratio of the counted number of pixels and the number of pixels in one picture. The DTL signal multiplication unit 10 controls a gain of a contour intensifying signal according to the signal regarding whether it is a flesh-colored part from the flesh-colored area detection circuit 8, and a skin DTL gain coefficient from the skin DTL gain control unit 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  According to the present invention, when outputting a video signal whose outline is emphasized in a television camera or the like having a zoom lens, the detail amount of the entire screen (degree of outline enhancement, hereinafter referred to as “DTL amount”) is not changed. The present invention relates to a skin detail circuit that reduces a partial DTL amount.

  In a television camera, an edge emphasis signal is created for a video signal obtained by imaging, and these signals are added and output. This is intended to improve the resolution, and is a well-known technique particularly for a broadcast television camera. The contour emphasis signal is created by extracting the contour component of the imaged object from the video signal acquired from the image sensor by a differentiation operation or the like.

The skin detail is a function for reducing the skin color portion DTL amount without changing the DTL amount of the entire screen. As a result, it is possible to avoid a situation where wrinkles, moles or the like of a person's face are emphasized by a contour signal, and a smoother expression can be performed (for example, see Patent Document 1).
Japanese Patent No. 2582701

  A TV camera uses a zoom lens for shooting. The skin DTL function is very effective when zooming up, because people's wrinkles, rough skin, moles, etc. are conspicuous. Conversely, when zooming back, the resolution of the flesh-colored portion of the image decreases, resulting in a blurred image. The inconvenience arises.

  An object of the present invention is to provide a skin detail circuit that makes a person's wrinkles, rough skin, moles, etc. inconspicuous in both zoom-up and zoom-back, and avoids a decrease in the resolution of the flesh-colored part during zoom-back. It is.

The skin detail circuit according to the present invention comprises:
An image signal is generated by photoelectrically converting an optical signal acquired through a zoom lens with a solid-state imaging device, and an outline enhancement signal with skin color correction is added to the imaging signal, thereby changing a detail amount of the entire screen. It is a skin detail circuit that reduces only the detail amount of the skin color part,
Detecting means for detecting whether the skin color part area and skin color part from the imaging signal;
A setting means for calculating a ratio of the area of the skin color portion to an area of the entire screen, and performing setting such that the skin detail gain increases as the ratio increases;
Control means for controlling the gain of the contour emphasis signal based on whether it is the skin color portion and the skin detail gain.

  According to the present invention, the area of the flesh color portion and whether or not the flesh color portion is detected from the imaging signal, the ratio of the flesh color portion area to the entire screen area is calculated, and the skin detail gain increases as the ratio increases. And the gain of the edge emphasis signal is controlled based on whether or not it is a skin color portion and the skin detail gain.

As a result, when the area ratio of the skin color portion is increased by zooming up, the skin DTL gain can be increased to make a person's wrinkles, rough skin, moles, etc. inconspicuous. On the other hand, when the area ratio of the flesh color portion is reduced by zoom back, the skin DTL gain can be reduced to avoid a decrease in the resolution of the flesh color portion of the video during zoom back.
In zoom back, since a person's wrinkles and rough skin are not conspicuous from the beginning, there is no effect even if the skin DTL gain is reduced.

  The skin detail gain increases, for example, linearly or quadratic as the ratio increases. Thereby, linear control or gradual control of the skin DTL gain can be performed.

An embodiment of a skin detail circuit according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing an embodiment of a skin detail circuit according to the present invention. This skin detail circuit includes input terminals 1, 2, 3, phase adjustment circuit units 4, 5, 6, DTL signal generation circuit unit 7, skin color area detection circuit 8, skin DTL gain control unit 9, A DTL signal multiplier 10, adders 11, 12, and 13, and output terminals 14, 15, and 16 are provided.

  An R signal, a G signal, and a B signal obtained from a solid-state imaging device such as a CCD are input to the input terminals 1, 2, and 3, respectively. The phase adjustment circuit units 4, 5, and 6 perform delays corresponding to the processing times of the DTL signal generation circuit unit 7, the flesh color area detection circuit 8, the skin DTL gain control unit 9, and the DTL signal multiplication unit 10.

  The DTL signal generation circuit 7 receives R, G, and B signals from terminals 1, 2, and 3, respectively, and generates and outputs a contour emphasis signal from the R, G, and B signals by a differentiation operation or the like. The flesh color area detection circuit 8 counts the flesh color part from the R signal, G signal, and B signal input to the terminals 1, 2, and 3 in units of one pixel or a plurality of pixels, and detects the flesh color area from the counted number. The skin DTL gain control unit 9 outputs a signal related to the skin color area, and the DTL signal multiplication unit 10 outputs a signal indicating whether the skin color portion is present.

  When an image near a human face is shown, the area of the face and neck becomes a skin color area, and the skin color area when zooming up as shown in FIG. 2 is compared with the skin color area when zooming back as shown in FIG. Become bigger.

  The skin DTL gain control unit 9 calculates the ratio between the number of pixels counted by the skin color area detection circuit 8 and the number of pixels in one screen (one field or one frame). The ratio calculated in this way is the area ratio of the skin color portion.

  A skin DTL gain coefficient with respect to the area ratio of the skin color portion is calculated based on the gain characteristic. The gain characteristic can be, for example, linear as shown in FIG. 4 or quadratic curve as shown in FIG. The skin DTL gain coefficient can be calculated by a memory element such as a ROM, and finer gain characteristics can be set using a look-up table or the like in addition to the power function.

  The DTL signal multiplication unit 10 enhances the contour from the DTL signal generation circuit unit 7 based on the signal indicating whether the skin color portion is from the skin color area detection circuit 8 and the skin DTL gain coefficient from the skin DTL gain control unit 9. The gain of the signal is controlled, and the DTL amount of the skin color portion of the contour enhancement signal is reduced and output.

  The adders 11, 12, and 13 respectively add the phase-adjusted R signal, G signal, and B signal to the contour enhancement signal that is skin DTL controlled. The output terminals 14, 15, and 16 output video signals with enhanced edges, respectively.

  At the time of zooming up as shown in FIG. 2, the area ratio of the skin color portion is increased by zooming up, so that the skin DTL amount, that is, the skin DTL gain is increased in order to make wrinkles, rough skin, moles, etc. inconspicuous. On the other hand, at the time of zoom back as shown in FIG. 3, the area ratio of the skin color portion is reduced by zoom back, so the skin DTL amount, that is, the skin DTL gain is reduced in order to improve the resolution. As a result, it is possible to avoid a decrease in the resolution of the flesh-colored portion of the video during zoom back.

The present invention is not limited to the above-described embodiment, and many changes and modifications can be made.
For example, the skin DTL gain coefficient can be set more finely by setting the skin DTL gain coefficient using a broken line gain characteristic other than the gain characteristic shown in FIG. 4 or FIG.

It is a figure which shows embodiment of the skin detail circuit by this invention. It is a figure which shows the image of zoom-up. It is a figure which shows the image of zoom back. It is a figure which shows an example of a gain characteristic. It is a figure which shows the other example of a gain characteristic.

Explanation of symbols

1, 2, 3 Input terminals 4, 5, 6 Phase adjustment circuit unit 7 DTL signal generation circuit unit 8 Skin color area detection circuit 9 Skin DTL gain control unit 10 DTL signal multiplication unit 11, 12, 13 Adder 14, 15, 16 Output terminal

Claims (2)

An image signal is generated by photoelectrically converting an optical signal acquired through a zoom lens with a solid-state imaging device, and an outline enhancement signal with skin color correction is added to the imaging signal, thereby changing a detail amount of the entire screen. It is a skin detail circuit that reduces only the detail amount of the skin color part,
Detecting means for detecting whether the skin color part area and skin color part from the imaging signal;
A setting means for calculating a ratio of the area of the skin color portion to an area of the entire screen, and performing setting such that the skin detail gain increases as the ratio increases;
A skin detail circuit comprising: control means for controlling the gain of the contour emphasis signal based on whether the skin color portion is present and the skin detail gain. 2. The skin detail circuit according to claim 1, wherein the skin detail gain increases linearly or quadratic as the ratio increases.

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