KR100446721B1 - Interpolation and contour compensating circuit of a digital still camera, in particular relating to increasing an effect of an image contour emphasis of an image signal by preventing the amplitude of a contour signal from getting smaller while increasing the frequency of the contour signal - Google Patents

Abstract

PURPOSE: An interpolating and contour compensating circuit of a digital still camera is provided to interpolate color signals separated from image signals while extracting contours at the same time, and to add the interpolated signals to contour signals, thereby preventing the contour signals from deteriorating while increasing an effect of emphasizing contours of a specific image. CONSTITUTION: A pickup unit(100) is applied with light, and converts the light into electrical image signals. A color signal separator(200) separates color signals from the image signals. An interpolator(300) is applied with output signals(R,G,B) of the color signal separator(200), and interpolates the applied signals. A contour extractor(400) is applied with the output signals(R,G,B), and extracts specific image contours of the applied signals. A contour compensator(500) adds up the output signals of the contour extractor(400) and the interpolator(300), and outputs the added signals.

Description

Interpolation and contour correction circuit of digital still camera

The present invention relates to an interpolation and contour correction circuit of a digital still camera. In particular, after each color signal is separated from an image signal input through an image pickup device, interpolation and contour extraction are simultaneously performed, and the interpolated signal and the contour signal are added. The present invention relates to an interpolation and contour correction circuit of a digital still camera, which is configured to output a digital output signal and is suitable for obtaining a clear image quality.

In general, a digital still camera uses a solid state image pickup device (CCD) as the image pickup device. The charge coupling device receives light and converts it into an electrical signal and outputs the output signal. The output signal of the charge coupling device is processed through interpolation, contour correction, and the like to obtain a clearer picture quality. When described in detail with reference to the accompanying drawings, the interpolation and contour correction circuit.

1 is a block diagram of a conventional digital still camera, and as shown therein, an image capturing unit 1 for converting an input of light into an electric video signal and outputting it; A color signal separation unit 2 which receives an image signal of the imaging unit 1 and separates color signals RGB; An interpolation unit 3 for interpolating the color signals R, G, and B of the color signal separation unit 2; Contour extraction and correction unit 4 for extracting and correcting the contour signal from the interpolated color signals R, G, and B, which are output signals of the interpolation unit 3.

Hereinafter, the operation of the interpolation and contour correction circuit of the conventional digital still camera configured as described above will be described.

First, when the shape of an external subject is applied to the image capturing unit 1 as light, the image capturing unit 1 converts the applied light into an electric video signal and outputs the converted image signal.

Next, the color signal separator 2 receiving the video signal of the imaging unit 1 separates and outputs the color signal RGB from the video signal.

Then, the interpolation unit 3 receiving the color signals R, G, and B separated by the color signal separation unit 2 interpolates the respective color signals and outputs all the color signals to each pixel. That is, the imaging device CCD provided in the imaging unit 1 displays only one color signal applied through a filter to each pixel. However, when displaying on the screen, each color signal must be displayed on one pixel. For this purpose, an interpolation process is required. This interpolation process can be expressed as shown in Equation 1 below.

A _i = (A _i-1 + A _{i + 1} ) / 2 ------- <Equation 1>

In other words, when the output signal of the color signal separation unit 2 is input to the interpolation unit 3 with 4 4 4 4 4 8 8 8 8 as shown in Fig. 3, the average value of the two signals is divided between the two signals. The output will be printed as 4444444446888.

Next, the contour extraction and correction unit 4 receiving the interpolated video signal as described above delays the interpolated video signal twice by using two delayers (not shown). Using>, we extract the contour from the video signal that has been delayed twice after its interpolation.

E _i = 2A _i -A _i-1 + A _{i + 1} ------- <Equation 2>

(Where, E _i is the contour, A _i-1 is the interpolation image signal, A _i is A _i-1 is the first delayed value, A _{i + 1} is A _i-1, the second delayed value)

The contour is extracted by using the interpolated video signal, the value of the first delay of the interpolated video signal, and the value of the second delay of the interpolated video signal as shown in Equation 2, and the extracted contour is used as the original video signal. The image quality is improved by emphasizing the outline of the video signal more clearly.

At this time, in case of extracting the contour directly without interpolation process, as shown in Fig. 2, the video signal is delayed twice, the non-interpolated video signal, the value of the first delay of the video signal, and the video signal The contours are extracted by substituting the second delayed values into Equation 2, respectively.

이 되며, 보간한 윤곽의 주파수는 보간 하지 않은 윤곽의 주파수의 3배가 됨을 알 수 있다. 이는 추출된 윤곽의 크기가 클수록 영상신호의 특정 이미지의 윤곽을 강조하는 효과가 증가하며, 윤곽의 주파수가 높을수록 이미지의 윤곽을 강조하는 효과가 증가하게 된다.As shown in Fig. 2 and Fig. 3, the value of the contour when the contour is extracted after interpolation is the value of the contour value when the contour is extracted without interpolation.

It can be seen that the frequency of the interpolated contour is three times the frequency of the non-interpolated contour. The larger the size of the extracted contour, the greater the effect of emphasizing the contour of a specific image of the image signal, and the higher the frequency of the contour, the greater the effect of emphasizing the contour of the image.

As described above, the interpolation and contour correction circuit of the conventional digital still camera increases the frequency of the contour signal when the contour is extracted after interpolation but decreases the value of the contour signal, and increases the value of the contour signal when extracting the contour without interpolation. However, since the frequency is reduced, the effect of emphasizing the image contour of the video signal is small, and thus the image quality is not good.

In view of the above problems, the present invention interpolates a digital still camera by improving the image quality by increasing the frequency of the contour signal and preventing the size of the contour signal from decreasing. And to provide a contour correction circuit.

1 is a block diagram of a conventional digital still camera.

FIG. 2 is a diagram for explaining a process of extracting contours from color signals not interpolated in FIG. 1; FIG.

FIG. 3 is a diagram for explaining a process of extracting contours from interpolated color signals in FIG. 1; FIG.

4 is a block diagram of a digital still camera according to the present invention;

Fig. 5 is a circuit diagram of the contour extraction section in Fig. 4;

Fig. 6 is a circuit diagram of contour correction in Fig. 4;

FIG. 7 is a waveform diagram of the main part of FIG. 4; FIG.

*** Description of the symbols for the main parts of the drawings ***

100: imaging unit 200: color signal separation unit

300: interpolation unit 400: contour extraction unit

410: Extraction unit 420: Government

500: Contour Water Administration

The above object is interpolated means for interpolating a color signal separated from an input video signal, contour signal extraction means for receiving the color signal and extracting a contour signal, and receiving the output signal and the contour signal of the interpolation means. And a first delay unit for delaying the color signal in synchronization with the first clock signal, and a delay delayed by the first delay unit in synchronization with the first clock signal. A second delayer for delaying the signal again, a first subtractor for subtracting the color signal from the output signal of the first delayer, and a second subtractor for subtracting the output signal of the second delayer from the output signal of the first delayer; An extraction unit provided; A first latch configured to latch and output an output signal of the first subtractor according to an input of a second clock signal having a period twice as long as the first clock signal, and the extraction unit according to an input of the second clock signal; A second latch for latching and outputting an output signal of a second subtractor provided therein; a first and gate outputting by combining the output signal of the first latch and the first clock signal; and the output signal of the second latch; And a correction unit including a second end gate for AND-combining and outputting a first clock signal, and an adder for extracting contours by adding output signals of the first and second end gates. A delay unit for delaying the output signal of the contour extraction means; This is achieved by adding an output signal of the delay unit and an output signal of the interpolator and outputting an image signal. The interpolation and contour correction circuit of the digital still camera of the present invention will be described in detail with reference to the accompanying drawings. Same as

4 is a block diagram of a digital still camera according to the present invention, which includes an image capturing unit 100 that receives light and converts the light into an electrical video signal; A color signal separator (200) for separating the color signal from the image signal of the imaging unit (100); An interpolation unit 300 for interpolating the output signals R, G, and B of the color signal separation unit 200; An outline extracting unit 400 receiving the output signals R, G, and B of the color signal separating unit 200 and extracting a specific image outline of the video signal; The contour extracting unit 400 and the interpolation unit 300 is configured to add and output the contour correction unit 500.

5 is a circuit diagram of the contour extracting unit 400. As shown in FIG. 5, the output signals R, G, and B of the color signal separation unit 200 are synchronized with the first clock signal CLK1. A first delay unit 411 for delaying, a second delay unit 412 for delaying the signal delayed by the delay unit 411 in synchronization with the first clock signal CLK1, and the first delay unit A first subtractor 413 which subtracts the output signals R, G, and B of the color signal separation unit 200 from the output signal of 411, and a second delay in the output signal of the first delay unit 411; An extraction unit 410 having a second subtractor 414 for subtracting the output signal of the unit 412; Latching and outputting an output signal of the first subtracter 413 included in the extractor 410 according to the input of the second clock signal CLK2 having a period twice as long as the first clock signal CLK1 A second latch LATCH2 for latching and outputting an output signal of the second subtractor 414 included in the extractor 410 according to the first latch LATCH1 and the second clock signal CLK2; The first and gate AND1 outputs the AND signal of the first latch LATCH1 and the first clock signal CLK1 in combination with each other, and the output signal and the first clock signal CLK1 of the second latch LATCH2. ) And an adder 421 for extracting a contour by adding output signals of the first and second AND1 AND1 and AND2. It is composed of a government (420).

6 is a circuit diagram of the contour compensator 500, and as shown therein, a delay unit 501 for delaying the output signal of the contour extractor 400; The adder 502 outputs an image signal by adding the output signal of the delay unit 501 and the output signal of the interpolator 300.

Hereinafter, the operation of the interpolation and contour extraction circuit of the digital still camera of the present invention configured as described above will be described.

First, the image capturing unit 100 that receives the light of the subject converts the light input into an electrical image signal and outputs it, and the color signal separation unit 200 receiving the image signal receives the color signals R, G, and B, respectively. And print it out.

Next, the interpolation unit 300 that receives the color signals R, G, and B of the color signal separator 200 interpolates the color signals R, G, and B, as shown in FIG. Output the same output signal.

At the same time, the contour extraction unit 400 receiving the color signals R, G, and B of the color signal separation unit 200 extracts the contour and outputs the contour.

Referring to the operation of the contour extraction unit 400, first, the first delay unit 411 is shown in Figure 7 (b) in accordance with the input of the first clock signal (CLK1) as shown in Figure 7 (a) The color signals R, G, and B as shown in Fig. 8) are delayed by one period of the first clock signal CLK1 to output an output signal as shown in Fig. 7C. The output signal of the delay unit 411 is applied to the second delay unit 412 and is delayed again by one cycle of the first clock signal CLK1 as shown in FIG.

Next, the first and second subtracting parts 413 and 414 respectively include a difference between the color signals R, G, and B and an output signal of the first delay part 411, and the first delay part 411. ), The difference between the output signal and the output signal of the second delay unit 412 is obtained, and an output signal as shown in Figs. 7E and 7F is output.

Next, the second and second subtractors 413 and 414 receive the output signals to their respective data input terminals D and have a period two times longer than the first clock signal CLK1. The first and second latches LATCH1 and LATCH2 receiving the clock signal CLK2 to the clock input terminal CK are latched and output in synchronization with the second clock signal CLK2.

The output signals of the first and second latches LATCH1 and LATCH2 are then combined with the second clock signal CLK2 at the first and second AND gates AND1 and AND2, respectively. It outputs as shown to 7 (g) and (h).

Next, the output signals of the first and second AND gates AND1 and AND2 are added by the adder 421 and output.

Next, the contour compensator 500 receiving the output signal of the interpolator 300 and the output signal of the contour extractor 400 receives the output signal of the contour extractor 400 from the delay unit 501. After delaying and synchronizing with the output signal of the interpolation unit 300, the adder 502 adds the output signal of the contour extracting unit 400 and the output signal of the interpolation unit 300, as shown in FIG. 7 (j). The video signal is output as shown.

As described above, the interpolation and contour correction circuit of the digital still camera of the present invention interpolates the color signal separated from the input video signal, extracts the contour, and adds the interpolated signal and the contour signal to the value of the contour signal due to the interpolation. There is an effect of improving the image quality of the video signal by preventing the degradation and increasing the effect of emphasizing the outline of the video signal specific image.

Claims (5)

Interpolation means for receiving and interpolating the color signal separated from the input video signal, Contour signal extracting means for receiving the color signal and extracting the contour signal, Contour for outputting and adding the output signal and the contour signal of the interpolation means An interpolation and contour correction circuit of a digital still camera, characterized by comprising correction means. The method of claim 1, wherein the contour signal extracting means receives a color signal and delays a predetermined step, and extracts the contour signal by combining the delayed color signal and the original color signal, and a predetermined period of the signal extracted by the extracting unit. The interpolation and contour correction circuit of a digital still camera, characterized by comprising a correction unit for reducing the period of the contour signal in half in combination with the clock signal of the signal. 3. The extractor of claim 2, wherein the extractor comprises: a first delay unit delaying the color signals (R, G, B) in synchronization with the first clock signal, and a delay delayed in the first delay unit in synchronization with the first clock signal; A second delayer for delaying the signal again, a first subtractor for subtracting the color signal from the output signal of the first delayer, and a second subtractor for subtracting the output signal of the second delayer from the output signal of the first delayer; Interpolation and contour correction circuit of a digital still camera, characterized in that the configuration. The first latch of claim 2, wherein the correction unit latches and outputs an output signal of the first subtractor according to an input of a second clock signal having a period twice as long as the first clock signal, and the second clock. A second latch for latching and outputting an output signal of a second subtractor provided in the extractor according to the input of the signal, a first end gate for performing an AND-combination of the output signal and the first clock signal of the first latch; And an adder for extracting a contour by adding an output signal of the first and second and gates by adding and outputting the second and gates by combining the output signal of the second latch and the first clock signal. An interpolation and contour correction circuit of a digital still camera. The apparatus of claim 1, wherein the contour correction means comprises: a delay unit for delaying an output signal of the contour extraction means; And an adder configured to add an output signal of the delay unit and an output signal of the interpolator to output an image signal.

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