KR100240254B1 - Method for peaking a video signal for compensation vertical edge and a video signal peaking circuit for performing the same - Google Patents

Abstract

A contour correction method for compensating an edge in the vertical direction in accordance with a motion of a luminance signal through a low pass filter and a contour correction circuit for performing the same are disclosed. The delay unit delays the input luminance signal for a predetermined time, the low pass filter lowers the input luminance signal, and the motion detector detects the detection signal based on the motion of the luminance signal, which is a low-frequency low-frequency image signal through the low pass filter. As a result, the smaller the amount of motion of the motion sensor is, the higher the amplification factor α value is in inversely proportional relationship with the variable amplifier. The adder adds the luminance signal delayed for a predetermined time and the variable amplified signal. That is, the low-pass filtered signal is delayed by 1H line, and the motion of the low-pass filtered signal is sensed with respect to the signal subtracted from the 1H delayed signal and the low-pass filtered signal. In many cases, the amount of edge compensation can be made very small, which can be configured according to the characteristics of the human eye, thereby improving image quality.

Description

Contour correction method for compensating vertical edges and contour correction circuit for performing the same

The present invention relates to a contour correction method for compensating vertical edges and a contour correction circuit for performing the same. In particular, in emphasizing a high frequency component in a vertical direction of a luminance component, a high frequency portion of a vertical portion is selected and applied to the high frequency portion. The present invention relates to a contour correction method capable of compensating edges in a vertical direction according to an amount of motion, and a contour correction circuit for performing the same.

In general, contour correction is an image quality adjustment known as sharpness adjustment. The sharpness can be improved by emphasizing the high range of the luminance signal. In order to improve the visual effect of the contour correction, a second differential phase correction is sometimes performed.

1 is a diagram showing a contour correction circuit for emphasizing the high range portion of a conventional luminance signal.

As shown in FIG. 1, the conventional contour correction circuit includes a first retarder 121, a first summer 131, and a second derivative circuit 100. The second differential circuit 100 performs second derivative of the luminance signal input from the luminance signal input terminal 101 to generate the contour correction signal 142. The second differential circuit 100 includes a second delayer 122, a third delayer 123, a second adder 132, a subtractor 141, and a half amplifier 151.

The first and second delayers 121 and 122 delay the luminance signal input through the input terminal 101 for a predetermined time T, respectively. The second delayer 122 outputs the luminance signal delayed by T time to the first summer 131 and the subtractor 141, respectively.

The third delayer 123 further delays the luminance signal delayed for the T time by the second delayer 122 by T time, and outputs the 2T time delayed luminance signal to the second summer 132.

The second summer 132 sums the luminance signal delayed by the third delayer 123 by the third delayer 123 to the current luminance signal input through the input terminal 101 and outputs the luminance signal to the 1/2 amplifier 151. do. The 1/2 amplifier 151 amplifies the summed luminance signal input from the second summer 132 a half and outputs the amplified signal to the subtractor 141. The subtractor 141 subtracts the 1/2 amplified signal from the 1/2 amplifier 151 from the T time delayed luminance signal from the second delayer 122 to generate a contour correction signal 142. In addition, the generated contour correction signal 142 is provided to the first summer 131. The first summer 131 sums the generated contour correction signal 142 from the subtractor 141 to the luminance signal delayed by the T time from the first delayer 121 to obtain the contour corrected luminance signal. Is generated and output to the matrix (not shown) through the output terminal 103.

Therefore, in the above-described conventional contour correction circuit, the high frequency portion of the luminance signal is simply emphasized, and there is a problem of over-correction or low-correction in the portion of the luminance signal having a high or low level.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and a first object of the present invention is to suppress a high frequency portion in a horizontal direction of a luminance signal, and to predict a vertical portion in a vertical direction according to a motion component. To provide a contour correction method that can compensate for.

It is also a second object of the present invention to provide a contour correction circuit which is particularly suitable for performing the above method.

1 is a block diagram showing a conventional contour correction circuit.

2 is a block diagram illustrating a contour correction circuit capable of compensating a vertical edge according to an embodiment of the present invention.

FIG. 3 is a flowchart for explaining the principle of the operation of the contour correction circuit capable of adjusting the vertical edge shown in FIG.

<Description of the code | symbol about the principal part of drawing>

101: input terminal 103: output terminal

121: delay unit 131: adder

210: low pass filter 220: 1H delay

230: subtractor 240: motion detector

250: variable amplifier

In order to realize the first object of the present invention, the present invention

Outputting a delayed signal by delaying an input luminance signal for a predetermined time;

Low-pass filtering the luminance signal to output a low-pass filtered signal;

Delaying the low-pass filtered signal by a 1H line to output a 1H delay signal;

Subtracting the 1H line delayed signal and the low pass filtered signal to output a subtracted signal;

Sensing a momentum of the low-pass filtered signal and outputting a detection signal;

Amplifying the subtracted signal by an amplification factor α and outputting an α amplified signal based on the detection signal; And

It provides a contour correction method comprising the step of adding the delay signal and the contour correction signal.

In order to achieve the second object of the present invention described above, the present invention

A delayer for delaying an input luminance signal for a predetermined time and outputting a delayed signal;

A low pass filter for low pass filtering the luminance signal to suppress a high range in a horizontal direction and output a high range portion in a vertical direction;

A 1H delayer for delaying the low-pass filtered signal by a 1H line;

A subtractor configured to subtract the 1H delayed signal and the low pass filtered signal to output a subtracted signal;

A motion detector for detecting an amount of exercise from the low-pass filtered signal;

A variable amplifier amplifying the subtracted signal by α based on the output signal of the motion detector; And

An outline correction circuit comprising a summer for adding up the delay signal and the outline correction signal is provided.

According to the present invention, the low-pass filtered signal is delayed by 1H line, and the amount of edge compensation is greatly increased when there is no motion by detecting the motion amount of the low-pass filtered signal with respect to the signal subtracted from the 1H delayed signal and the low-pass filtered signal. When there is a lot of motion, the amount of edge compensation is very small.

Therefore, by adjusting the amount of edge compensation according to the motion component of the low-pass filtered signal with respect to the signal subtracted from the 1H delayed signal and the low-pass filtered signal, it can be configured according to the characteristics of the human eye, thereby improving the image quality. have.

Hereinafter, with reference to the accompanying drawings, it will be described in detail the present invention through an embodiment of the present invention.

2 is a block diagram illustrating a contour correction circuit capable of compensating a vertical edge according to an embodiment of the present invention. Referring to FIG. 2, a contour correction circuit capable of compensating vertical edges according to the present invention includes a delay unit 121, a contour correction unit 200, and a summer 131.

The delay unit 121 outputs the delay signal 122 by delaying the first signal 102 of the luminance signal Y input from the input terminal 101 for a predetermined time T.

The contour correction unit 200 includes a low pass filter 210, a 1H retarder 220, a subtractor 230, a motion detector 240, and a variable amplifier 250. The contour correction unit 200 outputs the contour correction signal 251 by second-order differentiating the luminance signal Y input from the input terminal 101.

The low pass filter 210 receives the second signal 103 of the luminance signal Y from the input terminal 101 and performs low pass filtering on the filtered signal 211 to the 1H delayer 220 and the subtractor 230. And a motion detector 240.

The 1H delayer 220 receives the filtered signal 211 from the low pass filter 210, delays the filtered signal 211 by 1H line, and then subtracts the 1H line delayed signal 221. To provide.

The subtractor 230 performs a subtraction operation on the low pass filtered signal 211 and the 1H line delayed signal 221 to provide a subtraction operation signal 231 to the amplifier 250.

The motion detector 240 detects the amount of motion from the signal 211 filtered by the low pass filter 210, and outputs it as a motion detection signal 241. The motion detection signal 241 outputs a variable amplifier when the amount of motion is large. The variable amplifier 250 is adjusted by increasing the amplification factor α to a small value and increasing the amplification factor α when the momentum is small. In this case, the motion detector 240 generates a detection signal of logic high when the detected motion is greater than or equal to a predetermined reference size, and generates a detection signal of logic low when the motion is detected to be less than a predetermined reference magnitude.

The variable amplifier 250 subtracts the 1H delay signal 221 output from the 1H delayer 220 and the low pass filtered signal 211 based on the motion detection signal 241 of the motion detector 240 ( 231 is amplified at an amplification factor α to provide a contour correction signal 251 to the summer 131.

The adder 131 receives the delay signal 122 from the delayer 121 and the contour correction signal 251 output from the variable amplifier 250 and adds the sum signal to adjust the vertical edge of the output terminal. Through 103, it outputs as the last contour-corrected signal Y '.

The operation of the contour correction circuit configured as described above will be described in more detail with reference to the accompanying drawings.

FIG. 3 is a flowchart illustrating an operation principle of a contour adjustment circuit capable of adjusting the amount of compensation in inverse proportion to the amount of motion of the luminance signal in the vertical edge portion of the luminance signal shown in FIG. 2.

Among the luminance signals Y input through the input terminal 101, the first signal 102 is input to the delay unit 121, and the delay unit 121 delays the first signal 102 for a predetermined time. After that, a delay signal 122 is generated (step S1).

The second signal 103 of the luminance signal Y input through the input terminal 101 is provided to the low pass filter 210 in order to suppress the high frequency portion where the ratio of noise is relatively high, and the low pass filter 210. ) Suppresses the high frequency portion in the horizontal direction with respect to the input signal and generates the low frequency filtering signal 211 used for edge compensation by the operation of outputting the high frequency portion in the vertical direction (step S2).

The low pass filtering signal 211 generated by the low pass filter 210 is provided to the 1H delayer 220, and the 1H delayer 220 delays the 1H time to generate the 1H delay signal 221 ( Step S3).

The 1H delay signal 221 output from the 1H delayer 211 and the low pass filtering signal 211 output from the low pass filter 211 are provided to the subtractor 230, and the subtractor 230 is provided with a 1H delay signal ( 221 and the low pass filtering signal 211 are subtracted to generate a subtracted signal 231 (step S4).

In addition, the low-pass filtering signal 211 is provided to the motion sensor 240, the motion sensor 240 detects the amount of motion of the low-pass filtering signal 211 to generate a motion detection signal 241 (step S5).

The motion detection signal 241 of the low pass filtering signal 211 is provided to the amplifier 250 to change the amplification factor α of the amplifier 250. The amplifier 250 generates an amplified signal 251 by amplifying the subtracted signal 231 of the 1H delay signal 221 and the low pass filtering signal 211 by an amplification factor α so as to be inversely proportional to the magnitude of the sensing signal 241 ( Step S6).

The amplified signal 251 output from the variable amplifier 250 and the delay signal 122 output from the delayer 121 are added to generate a final contour corrected signal capable of correcting the vertical edge (step) S7).

In the contour correction circuit capable of compensating vertical edges having the above-described configuration, in particular, a signal passing through a low pass filter is used for edge compensation in order to suppress a high frequency portion having a relatively high noise ratio. In addition, by outputting only the high-pass section of the vertical section and multiplying it by the amplification factor α, the effect is emphasized. In addition, the motion detector 240 generates a detection signal 241 based on the motion of the luminance signal, which is a low-frequency low-frequency image signal through the low pass filter 210, so that the smaller the amount of motion of the motion detector 240, The value is increased and the momentum is inversely proportional to the variable amplifier 250. In this case, the amplification factor α is larger than 0 and smaller than 0.2, and when there is no motion, the amount of edge compensation is increased, and when there is a lot of motion, the amount of edge compensation is made very small so that the image quality can be improved by configuring it according to the characteristics of the human eye. Can be.

As described above, the present invention provides a momentum detection unit using a low pass filter after delaying an input luminance signal through a retarder and subtracting the input luminance signal to subtract the filtered signal and the signal delayed by the 1H line delayer. Adjust the amplification rate according to the degree detected by. Thereafter, the vertical edge can be compensated by adding the luminance signal by the delayer and the luminance signal whose luminance is adjusted. In this case, the momentum detector is used to adjust the amplification factor of the variable amplifier to increase the amount of edge compensation when there is no motion and to reduce the amount of edge compensation when there is a lot of motion. Can be.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

Claims (4)

Outputting a delayed signal by delaying an input luminance signal for a predetermined time; Low-pass filtering the luminance signal to output a low-pass filtered signal; Delaying the low-pass filtered signal by a 1H line to output a 1H delay signal; Subtracting the 1H line delayed signal and the low pass filtered signal to output a subtracted signal; Sensing a momentum of the low-pass filtered signal and outputting a detection signal; Amplifying the subtracted signal by an amplification factor α and outputting an α amplified signal based on the sensed signal; And adding the delay signal and the contour correction signal. According to claim 1, wherein the value of the amplification rate α is 0 to 0.2, the motion detection signal for detecting the momentum of the low-pass filtered signal is the value of the amplification rate α is closer to 0 as the detected amount of exercise increases, the amount of exercise The value of the amplification factor α approaches 0.2 as this decreases. A delay unit 121 for delaying the input luminance signal Y for a predetermined time and outputting a delay signal; A low pass filter (210) for low-pass filtering the luminance signal (Y) to suppress high frequencies in a horizontal direction, and output a high frequency portion in a vertical direction; A 1H delayer (220) for delaying the low-pass filtered signal (211) by 1H line; A subtractor 231 for performing a subtraction operation on the 1H delayed signal 221 and the low pass filtered signal 211 to output a subtracted signal 231; A motion detector 240 for detecting an amount of exercise from the low-pass filtered signal 211; A variable amplifier 250 that amplifies the subtraction signal 231 by an amplification factor α based on the output signal 241 of the motion detector 240; And a summer (131) for summing the delay signal and the contour correction signal. 4. The detection signal 241 of claim 3, wherein a value of the amplification factor α of the motion detector 240 is 0 to 0.2, based on the amount of motion of the luminance signal which is a low-frequency low-frequency image signal through the low pass filter 210. By adjusting the variable amplifier 250 so that the value of the amplification factor α is closer to the value of 0 as the momentum of the motion sensor 240 is larger, and the value of the amplification rate is closer to the value of 0.2 as the momentum is smaller. Contour correction circuit, characterized in that to compensate for the vertical edge.

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