KR920003394B1 - Motion Detection Circuit for Interpolation of Scanning Line of TV Signal - Google Patents

Abstract

No content.

Description

Motion Detection Circuit for Interpolation of Scanning Line of TV Signal

1a is a sampling structure and color phase diagram of the vertical-time axis plane of a television signal transmitted by interlaced scanning;

1b is a spectral diagram of the frequency domain of the signal of FIG.

2 is a circuit diagram according to the present invention.

3 is a frequency characteristic diagram according to the present invention.

3A is a frequency characteristic diagram of intrafield scan line interpolation,

3B is a frequency characteristic diagram of interfield scan line interpolation.

4 is an exemplary diagram of characteristics of the second level conversion circuit 210 according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion detection circuit in a television receiver. In particular, in converting a television signal transmitted by interlaced scanning into a sequential scan, a scan line interpolation function is adaptively processed according to a motion component of the signal to detect accurate motion. The present invention relates to a motion detection circuit for scanning line interpolation of a TV signal.

In general, in converting a television signal transmitted by interlaced scanning into sequential scanning, a motion detection circuit is required in order to be able to adaptively process the scanning line interpolation function according to the motion component of the signal. It is widely used in high definition TV.

For example, an interlaced television signal is shown in a sampled form of an offset in time, vertical plane as shown in FIG. 1a, which is shown in FIG. 1b in the form of time and a vertical axis in the frequency space.

Here, in sequential scanning, the keyier enters the empty area by interlaced scanning, whereby the line flicker phenomenon caused by (a) and the flat line moving image by (b) Disturbance causes image quality deterioration.

To eliminate this, interpolation scan is converted to sequential scan, and scanning line interpolation is performed to remove carrier of (C). This scanning line interpolation can be adaptively processed according to the degree of movement (movement) to double the effect. .

However, the conventional dynamic detection method uses two frames to detect phase by phase of color signal by color subcarrier, and detects motion by using the detected coral. This difficulty prevented the creation of motion signals for smooth motion adaptive scanline interpolation.

Accordingly, an object of the present invention is to provide a circuit capable of adaptively processing a scan line interpolation function according to a motion component of a signal in converting a television signal transmitted by interlaced scanning into a sequential scan. have.

In order to accomplish the above object, the present invention uses a frame memory, a subtractor, a low pass filter, and an absolute value circuit to detect a motion signal in a scan line interpolation that is performed to remove a deterioration factor of image quality. The first means for detecting the motion signal and the frame memory used for the motion signal detection of the luminance band, and the motion signal in the color band (or high range) from the band pass filter, the absolute value circuit, the subtractor and the multiplier. The second means for detecting and the output value of the said 1st, 2nd means select a maximum value by a 1st maximum value circuit, and a 1st level converting circuit changes a number of bits of a sample, And correcting the corrected signal by a field memory, a line memory, a second maximum value circuit, a sample delay, and a third maximum value circuit. And a second level conversion circuit for converting the motion signal to a value in the range 0-1 so that the motion signal can be used for scanning line interpolation. .

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a circuit diagram according to an embodiment of the present invention, wherein the first motion detecting unit 250 stores a frame memory 10 for storing an image signal converted into digital data in frame units corresponding to one screen, and the digitalized image data. A subtractor 20 subtracting the output of the frame memory 10, a divider 30 dividing the output of the subtractor 20, and a low pass filtering the luminance band from the output of the divider 30. A pass filter 40 and a first absolute value circuit 50 for converting the output of the low pass filter 40 into an absolute value to detect the movement of the luminance band (or the low pass).

The second motion detecting unit 260 may include first and second band pass filters 60 and 70 for filtering the digitalized image data and the output data of the frame memory 10 in color bands, and the first and second bands. First and second absolute value circuits 80 and 90 for converting the outputs of the pass filters 60 and 70 to absolute values, and a second subtractor subtracting the outputs of the first and second absolute value circuits 80 and 90, respectively. 100, a fourth absolute circuit 100 converting the output of the second subtractor 100 into an absolute value, and a multiplier 120 multiplying the output of the fourth absolute circuit 100 by a predetermined value. It is composed.

A first maximum value circuit 130 for selectively outputting the maximum values of the first and second motion signal detection means 250 and 260 and the first maximum value circuit 130 to receive the output of the first and second motion signal detection means; A first level converting circuit 140 for firstly correcting a signal, a field memory 150 capable of storing one field of a screen for output data of the first level converting circuit 140, and the field memory 150 Line memory 160 for storing the data read from each line), and a second maximum value circuit for selectively outputting the maximum value output from the first level conversion circuit 140, the field memory 150, and the line memory 160. And first and second delay elements 180 and 190 for delaying the output of the second maximum circuit 170 by one sample (one sample delay is delayed by the inverse of the sampling frequency). A third maximum circuit 200 for selecting the maximum output of the second maximum circuit 170 and the first and second delay elements 180 and 190; And a second level converting circuit 210 for converting the number of bits into a value in the range 0-1 so that the motion signal output from the third maximum circuit 200 can be used for interpolation.

3 is a frequency characteristic diagram according to the present invention, FIG. 3a is a frequency characteristic diagram of scan line interpolation in a field, and FIG. 3b is a frequency characteristic diagram of inter-field scan line interpolation.

4 shows an example of the second level conversion circuit 210.

Therefore, a specific embodiment of the present invention will be described in detail with reference to FIGS. 2 to 4, but the interlaced scanning of a television signal (MTSC method) can halve the transmission frequency bandwidth, but when the resolution of the receiver is improved. Thin horizontal flicker is generated, and in a moving picture, image quality deterioration occurs such as a field image formed from a rough scan line structure.

In order to eliminate such deterioration factors, scanning line interpolation is performed to convert interlaced scanning into sequential scanning. Such scanning line interpolation can be performed by using an adjacent vertical pixel or by operation of pixels in adjacent fields.

The spectral structure of the interlaced television signal is shown in FIG. 1, where the hatched portion is the baseband signal (fv is 525, fT is 60, fv, fT is the vertical and time axis sampling frequencies, respectively).

Line in the edge portion of the yellow pattern which changes rapidly in the vertical direction in the signal region (the rhombic frequency region) having the carrier of (C) of FIG. 1B formed by interlaced scanning, by the influence of the part (A) of FIG. Flickering occurs, and the disturbance of the scanning line that passes through the flat moving image appears due to the region (b) of FIG. 1b.

Therefore, as shown in FIG. 3, the scanning line interpolation for removing the image quality deterioration factor may further intensify image quality when fixed in either direction in the interpolation between fields or between fields.

That is, in the case of FIG. 3a, D and E are used when interpolating C of FIG. 1a. In this case, the pass band is hatched.

In this case, the area of <b> is removed (attenuated), so that the disturbance of the rough scan line structure in the flattened moving picture cannot be recognized, but the baseband signal (c) is attenuated for the line flicker generated in the still image, and <a> remains. It becomes annoying more than an original image.

In the case of interpolating C of FIG. 1a with A and B (or A) as shown in FIG. 3b, the line flicker does not occur due to the attenuation of a Deterioration is seen.

Therefore, in order to ensure such scanning line interpolation, the processing in the field and the field must be mixed according to the state of the image, and for this reason, the state of movement of the image is detected. However, the conventional motion detection circuit performs two-frame detection because the color phase is inverted from frame to frame, but it cannot obtain a motion signal for fast movement within two frame periods.

However, the present invention proposes a circuit capable of recognizing movement even with fast movement by a combination of operations between a frame and a field.

Referring to FIG. 1a, a motion signal obtained by one frame difference of D ', D, A, B, E', and E is obtained only for a low band without a color band to detect a motion signal for interpolating a sample point of C- (Because the color signal is inverted frame by frame, an error may occur in the detection of 1 frame motion)-Here, a signal corresponding to the color signal is obtained by using a band pass filter having a pass region corresponding to the color band. The motion signal obtained by one frame difference is obtained by using the motion signal. The larger value is used as the motion signal, and the maximum value is obtained through a comparison circuit having an average meaning (a kind of smoothing) on the horizontal axis.

Through such a circuit, the degree of motion for scanning line interpolation at point C can be reliably determined, and a motion signal capable of adaptively mixing the scanning line interpolation of FIGS. 3A and 3B according to the movement can be obtained.

The embodiment according to the present invention will be described in detail with reference to FIG. 2. When a digitally changed video signal is input in the analog, the frame memory 10 is delayed by about one frame, and the digital signal and the digitalized video signal are delayed. Subtraction is performed in the first subtractor 20. The subtracted value is averaged by dividing the divider 20 by two (the divider 20 is actually processed by removing the least significant bit of the first subtracter 20). This value passes 0-2.1 MHz. Only a value for the luminance signal is obtained by passing through the low pass filter 40. The absolute value is passed through the first absolute value circuit 50 to be input to the first maximum value circuit 130.

In addition, the first frame delayed signal and the current input signal of the video signal in the first and second band pass filters 60 and 70 (color band, band pass filter centered on 2.1-4.2 MHz 4 or 3.58 MHz), respectively. Passed through, a signal corresponding to the color signal component (or a high frequency signal of the luminance signal) is obtained.

These absolute values are taken from the second and third absolute circuits 80 and 90 to obtain one frame difference through the second subtractor 100 as described above. The absolute value is changed in the fourth absolute value circuit 110, and the signal is multiplied by the multiplier 120 to give a weighting value.

The multiplier 120 inputs the signal weighted by the value of α to the first maximum circuit 130 (where α is a variable value and a range of 0-3 is appropriate).

The signal input to the first maximum value circuit 130 selects a signal having a large value by comparing the two signals, that is, the outputs of the first absolute value circuit 50 and the multiplier 120, to the first level conversion circuit 140. In the first level converting circuit 140, the number of bits of the output value of the first maximum value circuit 130 is reduced (for example, 8 bits to 4 bits) by a method of reducing the number of bits of data. )

Using this value, the maximum value of the outputs A, B, and C delayed by the field memory 150 and the line memory 160 of the 262 line delay is obtained from the second maximum circuit 170.

Here, the input A of the output terminal of the line memory 160 corresponds to the operation of D and D 'in FIG. 1A, the input B corresponds to the operation of E and E', and the input of C corresponds to the operation of A and B.

sec, fsc는 칼라 부반송파 주파수)를 이용하여 수평축 방향의 연속하는 3샘플점의 움직임의 최대치를 구함으로써 이를 통해 일종의 평균적 의미를 움직임 검출의 누락에 대해 상당한 정도 보정할 수 있다.The maximum motion output output from the second maximum circuit 170 is again sample delay (sample delay is

sec, fsc is the color subcarrier frequency) to obtain the maximum value of the motion of three consecutive sample points in the horizontal axis direction, thereby making it possible to correct a kind of average meaning for the omission of motion detection to a large extent.

The output signal of the second maximum circuit 170 is delayed by one sample and two samples through the first and second delay elements 180 and 190, so that the output of the second maximum value circuit 170 and the first and second delay elements 180 and 190 are delayed. Each output of is input to the third maximum circuit 200.

The third maximum value circuit 200 detects the final motion signal by selecting the maximum value by comparison. The motion signal is output by the second level converting circuit 210 in the range of 0-1 with respect to the input value by the function characteristic as shown in FIG.

The characteristics of the second level conversion circuit 210 are linear in the threshold operation and ab section so that the output value becomes zero when the output value of the third maximum value circuit 200 is a value (or It can be configured nonlinearly) Fixed to 1 for inputs of b or more.

Using this value, the above-described scan line interpolation can be adaptively adapted to the movement.

As described above, in converting a television signal transmitted by interlaced scanning sequentially, a high-definition television can be realized by adaptively processing a scanning line interpolation function according to a motion component of a signal.

Claims (3)

A motion detection circuit for scanning line interpolation in a television receiver, wherein the digitalized video signal data of the television receiver is stored by one frame, subtracting a signal and previous data from the frame memory 10 by one; A first motion detection means 250 for obtaining a motion signal at a low band without a color band by a frame difference, and a signal corresponding to the color of the television receiver from a signal through the frame memory 10 and previous data, and then obtained one frame. A second motion detection means 260 for obtaining a motion signal by a difference, a first maximum value circuit 130 for selectively outputting a maximum value of the first and second motion signal detection means 250, 260, and the first maximum value circuit A first level converting circuit 140 which firstly corrects the detected motion signal by converting the number of bits of a sample by receiving the output of 130 and the first level converting circuit 140 A field memory 150 capable of storing one field of a screen for output data, a line memory 160 for storing data read from the field memory 150 for each line, and the first level conversion circuit 140. The second maximum circuit 170 selects and outputs a maximum value from the values output from the field memory 150 and the line memory 160, and a first delay of each of the outputs of the second maximum circuit 170 by one sample. A third maximum circuit 200 for selecting a maximum value from the maximum outputs of the second delay elements 180 and 190, the second maximum value circuit 170, and the first and second delay elements 180 and 190, and the third maximum value circuit ( And a second level conversion circuit (210) for converting the number of bits to a value in the range 0-1 so that the motion signal output from the signal 200 can be used for scanning line interpolation. The method of claim 1, wherein the first motion detecting unit 250 divides the output of the digitalized image data and the frame memory 10, and divides the output of the subtractor 20 by two. The period 30, the low pass filter 40 for filtering a signal corresponding to the luminance band at the output of the divider 30, and the output of the low pass filter 40 is converted into an absolute value to convert the luminance band ( Or a first absolute value circuit (50) for detecting low-pass motion. The first and second band pass filters 60 and 70 of claim 1, wherein the second motion detection unit 260 filters the digitalized image data and the output data of the frame memory 10 for color bands, respectively. And the first and second absolute value circuits 80 and 90 for converting the outputs of the first and second band pass filters 60 and 70 into absolute values, respectively. A second subtractor 100 for subtracting the output, a fourth absolute circuit 110 for converting the output of the second subtractor 100 into an absolute value, and an output of the fourth absolute value circuit 110 for a predetermined value. A circuit, characterized in that consisting of a multiplication (120) to multiply by.

Images