KR100552685B1 - Method and apparatus for converting interlaced image into sequential image - Google Patents

Abstract

The present invention discloses a method and apparatus for converting an interlaced image into a sequential image. The image conversion method of the present invention comprises the steps of: (a) detecting a motion of a pixel to be interpolated of an input field image using preceding field images and trailing field images; (b) when the motion is detected, determining the interpolation direction of the pixel to be interpolated using pixel values on another scan line; (c) spatially interpolating a pixel to be interpolated using a predetermined filter along the interpolation direction; And (d) resetting the value of the pixel to be interpolated using the corresponding pixel values of the preceding field and the trailing field, and the spatially interpolated pixel values, if there is a vertical high frequency component in the pixel to be interpolated.

Description

Method and apparatus for converting the interlaced images into progressive images.

1 is a diagram illustrating a pixel layout for describing a conventional edge-dependent interpolation scheme.

FIG. 2A is a block diagram showing the configuration of an interlaced scan image conversion apparatus according to a preferred embodiment of the present invention, and FIG. 2B is a detailed block diagram showing the configuration of the interpolation direction determiner 220 shown in FIG. 2A.

3A is a flowchart illustrating a method of converting interlaced scan images according to an exemplary embodiment of the present invention, and FIG. 3B is a detailed flowchart of step S320 of FIG. 3A.

4 is a layout view of pixels for explaining a motion detection method of the present invention.

5 is a pixel layout view illustrating a method of determining an interpolation direction according to an exemplary embodiment of the present invention.

FIG. 6 is a pixel layout view illustrating a method of performing spatial filtering using only information of a current input field according to the determined interpolation direction.

7A to 7C and 8A to 8C are diagrams illustrating input interlaced images, sequential scan images converted according to the present invention, and sequential scan images converted according to the prior art, respectively.

The present invention relates to a method and apparatus for converting an interlaced image into a progressive image. Specifically, a method for converting an interlaced image into a progressively scanned image by interpolating the interlaced image in the direction of a pixel. And to an apparatus.

As a method of converting interlaced images into sequential scan images, various techniques are known. Two representative methods are a blend method and an edge dependent interpolation method, which are briefly described as follows.

The blending method is a method of interpolating a pixel value of an interlaced scan of a pixel to be processed and an upper and lower pixel value in the vertical direction of the pixel, and then using the interpolated value as the value of the pixel to be processed. This method is particularly advantageous in that the edges of an image can be smoothly and naturally expressed. However, when the interlaced scan image having a lot of motion is transformed by using the above-described method, there is a drawback of blurring and afterimages, and a step of generating a stepped edge when expressing an oblique edge portion.

), 왼쪽 아래 대각선 방향 화소값(

), 오른쪽 위 대각선 방향 화소값(

), 오른쪽 아래 대각선 방향 화소값(

), 상하 화소값(

)을 사용한다.The edge dependent interpolation method uses the upper and lower pixel values of the pixel to be processed and the left and right pixel values of the upper and lower pixel values to obtain the pixel value to be processed, as shown in FIG. 1. To obtain the sequentially scanned pixel value (X '),

), Lower left diagonal pixel value (

), The upper right diagonal pixel value (

), Lower right diagonal pixel value (

), The top and bottom pixel values (

).

), 대각선 방향 화소값의 차(

)를 구해 그 차가 가장 작은 방향의 값으로 처리대상 화소값(X)을 보간하여 순차주사된 화소값(X')을 구한다. 이 방식은 상술한 바와 같이 대각선 방향의 화소를 고려하므로 자연스러운 사선 에지 표현이 가능하여 계단 현상을 방지시킬 수 있는 장점이 있다.This method uses the difference between the upper and lower pixel values

), The difference between the diagonal pixel values (

) Is obtained, and the pixel value X 'sequentially scanned is obtained by interpolating the pixel value X to be processed in the direction in which the difference is the smallest. As described above, since the pixels in the diagonal direction are considered as described above, natural diagonal edges can be expressed, thereby preventing the step phenomenon.

However, this method has the risk of error in the determination of the diagonal direction of the boundary (edge), and since only one field of the interlaced scan image is used for interpolation, the chromaticity value of the interlaced image and the chromaticity of the sequential scan image differ significantly. There is a problem that a color bleeding phenomenon may occur during the sequential conversion of the image that can fly and fast moving the subject. That is, in order to use this method, it is important to determine whether it is advantageous to interpolate each pixel in the diagonal direction or to interpolate in the vertical direction.

  Conventional methods mostly use the absolute value | x (k)-y (-k) | of the difference between the pixel values on the upper scan line and the pixel values on the lower scan line to determine the oblique direction. Use the method k,-= N, .., 0, .... N to determine that there is an oblique line in the direction with the smallest value. However, this method requires a comparison of the absolute values of the combinations of the up and down pixels in the diagonal direction as possible, so that all possible diagonal lines are complex and some types of diagonal lines are needed. If only checked, there is a problem that noise may be caused by wrong judgment because the slant of the unchecked direction is not considered.

In addition, motion estimation is required for accurate conversion, but this method requires a lot of computational power and memory bandwidth, so it is difficult to convert interlaced images in real time.

The technical problem to be achieved by the present invention is to determine the motion only and adaptively convert the interlaced scan image to the sequential scanning image, and by judging the diagonal of various angles at once and interpolating in the diagonal direction, the complexity of the diagonal determination becomes low. Therefore, to provide a conversion method and apparatus that can mitigate the zigzag phenomenon of the diagonal portion while reducing the noise caused by the wrong diagonal determination.

According to an aspect of the present invention, there is provided a method of converting an image, the method comprising: (a) detecting a motion of a pixel to be interpolated of an input field image using preceding field images and trailing field images; (b) when the motion is detected, determining the interpolation direction of the pixel to be interpolated using pixel values on another scan line; (c) spatially interpolating a pixel to be interpolated using a predetermined filter along the interpolation direction; And (d) resetting the value of the pixel to be interpolated using the corresponding pixel values of the preceding field and the trailing field, and the spatially interpolated pixel values, if there is a vertical high frequency component in the pixel to be interpolated.

In addition, in the step (a) of the above-described conversion method, it is preferable to detect the motion by using a difference between the pixels of the preceding field images and the following field images, which correspond to adjacent pixels of the pixel to be interpolated.

In addition, in step (a) of the above-described conversion method, the difference between the pixels of the preceding field image and the pixels of the trailing field image corresponding to the first pixel to be interpolated and adjacent second pixels on the same scan line as the first pixel. The difference between the pixels of the preceding field image corresponding to the third and third pixels on the upper and lower scanning lines adjacent to the first pixel, and the pixels of the following field image corresponding to the third pixel. It is desirable to detect the movement by using the.

Also, in the step (a) of the above-described conversion method, when it is determined that there is no movement of the pixel to be interpolated, the pixel value of the preceding field image corresponding to the pixel to be interpolated is set as the pixel value of the pixel to be interpolated and the pixel to be interpolated. It is preferable to further include the step of interpolating.

Further, in the step (b) of the above-described conversion method, if the difference between the pixel value on the upper scan line corresponding to the pixel to be interpolated and the pixel value on the lower scan line is less than a predetermined threshold value, the interpolation direction of the pixel to be interpolated is set in the vertical direction. If it is determined to be equal to or larger than a predetermined threshold value, it is preferable to determine whether the interpolation direction of the pixel to be interpolated is diagonal or vertical.

Also, in the step (b) of the above-described conversion method, if the difference between the predetermined number of pixel values on the upper scan line adjacent to the pixel to be interpolated and the predetermined number of pixel values on the lower scan line is larger than the threshold value, the interpolation is performed in the direction of minimizing the difference. It is desirable to determine the direction.

Further, step (b) of the above-described conversion method may include: (b1) obtaining a first difference value between pixels located in an upper scan line and a lower scan line in a first oblique direction in the input field image, centering on a pixel to be interpolated; (b2) obtaining a second difference value between pixels located in an upper scan line and a lower scan line in a second oblique direction in the input field image centering on a pixel to be interpolated; (b3) obtaining a third difference value between the first difference value and the second difference value and comparing it with a predetermined threshold value; And (b4) determining the interpolation direction in a direction corresponding to a smaller difference value between the first difference value and the second difference value when the third difference value is larger than the threshold value.

In addition, in the step (d) of the above-described conversion method, the spatially interpolated pixel value is multiplied by a predetermined first weight, and the corresponding pixel value of the preceding field and the corresponding pixel value of the subsequent field are multiplied and added to the predetermined second weight. It is preferable to reset the value of the pixel by dividing one result by a predetermined constant.

On the other hand, the image conversion apparatus of the present invention for achieving the above-described technical problem, the motion detection unit for detecting a motion using the preceding field images and the following field images for the pixel to be interpolated of the input field image; An interpolation direction determiner which determines an interpolation direction of a pixel to be interpolated from which motion is detected using pixel values on another scan line; A first interpolation unit for spatially interpolating pixels to be interpolated using a predetermined filter along the interpolation direction; And a second interpolation unit for resetting the values of the pixels to be interpolated by using corresponding pixel values of the preceding field and the following field and spatially interpolated pixel values when the vertical high frequency component exists in the pixel to be interpolated.

In addition, it is preferable that the above-described motion detector of the conversion device detects motion by using a difference between pixels of preceding field images and trailing field images corresponding to adjacent pixels of the pixel to be interpolated.

The motion detector of the above-described conversion apparatus may further include a difference between pixels of the preceding field image and pixels of the following field image corresponding to the first pixels to be interpolated and adjacent second pixels on the same scan line as the first pixel. By using the difference between the pixels of the preceding field image corresponding to the third pixel and the third pixel on the upper and lower scanning lines adjacent to one pixel, and the pixels of the following field image corresponding to the third pixel, It is desirable to detect movement.

In addition, the above-described conversion apparatus may include a third interpolation unit that interpolates the pixel to be interpolated by setting the pixel value of the preceding field image corresponding to the pixel to be interpolated with no motion as the pixel value of the pixel to be interpolated. It is preferable to further include.

In addition, the interpolation direction determination unit of the above-described conversion apparatus determines the interpolation direction of the pixel to be interpolated in the vertical direction when the difference between the pixel value on the upper scan line and the pixel value on the lower scan line corresponding to the pixel to be interpolated is less than a predetermined threshold value. If it is equal to or greater than a predetermined threshold value, it is preferable to determine whether the interpolation direction of the pixel to be interpolated is an oblique direction or a vertical direction.

Further, the interpolation direction determiner of the above-described conversion apparatus interpolates in a direction in which the difference is minimum when the difference between a predetermined number of pixel values on the upper scan line adjacent to the pixel to be interpolated and a predetermined number of pixel values on the lower scan line is larger than a predetermined threshold value. It is desirable to determine the direction.

In addition, the interpolation direction determiner of the above-described conversion apparatus calculates a first difference value that calculates a first difference value between pixels located in an upper scan line and a lower scan line in a first oblique direction in the input field image based on the pixels to be interpolated. part; A second difference value calculator for calculating a second difference value between pixels located in an upper scan line and a lower scan line in a second oblique direction around the pixel to be interpolated; When the third difference value between the first difference value and the second difference value is obtained and the third difference value is larger than the predetermined threshold value, the interpolation direction in the direction corresponding to the smaller difference value between the first difference value and the second difference value. It is preferable to include a direction determining unit for determining the.

In addition, the second interpolation unit of the above-described conversion apparatus multiplies the spatially interpolated pixel value by a predetermined first weight, and multiplies and adds the corresponding pixel value of the preceding field and the corresponding pixel value of the subsequent field by a predetermined second weight. It is desirable to reset the value of the pixel by dividing the result by a predetermined constant.

Hereinafter, with reference to the accompanying drawings, a conversion method and apparatus according to a preferred embodiment of the present invention will be described.

2A is a block diagram showing the configuration of an interlaced scan image converting apparatus according to a preferred embodiment of the present invention. The converter of the present invention includes a motion detector 200, an interpolation direction determiner 220, a first interpolator 230, a second interpolator 240, a third interpolator 210, and an output unit 250. It includes.

2B is a detailed block diagram illustrating the configuration of the interpolation direction determiner 220 illustrated in FIG. 2A. The interpolation direction determiner 220 includes a vertical difference calculator 222 and a first difference calculator. 224, a second difference value calculator 226, and a direction determiner 228.

3A is a flowchart illustrating a method of converting interlaced scan images according to a preferred embodiment of the present invention. Referring to FIG. 3A, a method of converting an interlaced image of the present invention into a progressive scan image will be described.

First, the interlaced image is input to the motion detector 200, and the motion detector 200 determines whether motion is detected. The operation of the motion detector 200 will be described with reference to FIG. 4, which is a pixel arrangement diagram for explaining the motion detection method of the present invention.

As shown in FIG. 4, since there is almost no change in pixel values between the preceding field image and the trailing field image of the input field image when there is no motion, the pixel values of the preceding field images and the following field images are changed. The method determines whether there is motion in the pixel of the currently input field image. The motion detector 200 obtains a value M representing the degree of change of the pixel value using two preceding field images and two trailing field images according to Equation 1 below, and when the M value is smaller than a predetermined threshold, the motion is detected. It is determined that there is no, and if the M value is larger than the predetermined threshold value, it is determined that there is motion.

M = | g-j | + | h-k | + | i-l | + | a-m | + | b-n | + | c-o | + | d-p | + | e-q | + | f-r | + | a-s | + | b-t | + | c-u | + | d-v | + | e-w | + | f-x |

In Equation 1 and FIG. 4, X represents a pixel to be interpolated in the currently input field image, and a to x represent pixel values of the field image shown in FIG. 4.

If the motion detector 200 determines that there is no motion in the pixel of the input field image, the third interpolator 210 interpolates the pixel to be interpolated of the input field image to a corresponding pixel of the preceding field image. The pixel value of the preceding field is set as the pixel value to be interpolated in the input field.

Hereinafter, the case where the motion is detected will be described with reference to FIG. 5 which is a pixel arrangement diagram for explaining the interpolation direction determination method according to the preferred embodiment of the present invention, and FIG. 3B which is a detailed flowchart of S320.

When the motion detector 200 determines that there is motion in the pixel to be interpolated, first, in order to determine whether the interpolation direction is the vertical direction, the vertical difference value calculator 222 of the interpolation direction determiner 220 determines the following equation (2). When the value is calculated and the calculated value is output to the direction determiner 228, the direction determiner 228 compares the input vertical difference value vert with a predetermined threshold value T1 (S321).

vert = | E-B |

In Equation 2, B and E refer to pixel values above and below the pixel to be interpolated, as shown in FIG. 5.

If the vertical difference value is less than the threshold value T1, the direction determiner 228 determines the interpolation direction in the vertical direction and outputs the interpolation direction to the first interpolator 230 (S323).

On the other hand, when the vertical difference value is greater than or equal to the threshold value T1, the direction determiner 228 receives the difference value in the first diagonal direction shown in FIG. 5 from the first difference value calculator 224, and The difference value calculation unit 226 receives the difference value in the second oblique direction shown in FIG. 5, and calculates a bias value as shown in Equation 3 below (S325).

 Bias = || -B-C + D + E | -| -A-B + E + F ||

In Equation 3, | -B-C + D + E | represents a difference value in the first diagonal direction input from the first difference value calculator 224, and | -A-B + E + F | represents a second value. The difference value in the second diagonal direction input from the difference value calculation unit 226 is shown.

After that, the direction determining unit 228 checks whether the input Bias value is larger than the predetermined threshold value T2 (S327), and if the Bias value is not larger than the threshold value T2, determines the interpolation direction as the vertical direction. If the bias value is greater than the threshold value T2 (S323), the interpolation direction is determined in an oblique direction according to the bias (S329).

Steps S327 and S329 are described in detail. Once it is determined that the high frequency component is present in the vertical direction, i.e., it is determined that the difference between the value of the upper pixel and the lower pixel of the pixel to be interpolated is large, it should be determined whether the pixel to be interpolated is included in the diagonal region. . As shown in FIG. 5, to determine the direction of the current pixel X, values of the upper three pixels and the lower three pixels of X are used, and the weights of the upper pixels A, B, and C, and the lower pixels D and E are used. , The sign of the weight of the value of F is reversed, and the direction is determined by multiplying the weight. The effect of adding the signs of the pixels belonging to the upper and lower scan lines differently is that when one pixel of the upper scan line and one pixel of the lower scan line have similar values, the different signs add up to a number close to zero, so the total sum is This is because the value is small, so that the diagonal line can be detected because it is different from the value when there is no similar value. After all, this is the same as finding the difference between the pixel values, and by calculating as described above, the diagonal line is added by differently adding the sign of the upper scan line and the lower scan line without considering the number of all cases where the diagonal lines come out in the various pixel groups. Can be detected.

The direction determining unit 228 uses the Bias value of Equation 3 above to determine the diagonal direction. When the bias value is larger than the threshold value T2, the direction determining unit 228 determines the diagonal direction in the direction of the difference value having the smallest absolute value. That is, Bias> T2 and | -B-C + D + E | <| -A-B + E + F | If it is determined that a diagonal line exists in a 1st diagonal direction (upper left lower direction), | -B-C + D + E | > | -A-B + E + F | If it is, it is determined that the diagonal lines exist in the second diagonal direction (left upper right lower direction).

In order to determine whether a pixel belongs to the vertical direction or the oblique direction, existing methods generally use the absolute value of the difference between the upper and lower pixel values to determine whether there is an edge in the direction. It is advantageous to make direction determination to find edges of various angles compared to using one at a time. In the example of FIG. 5, edges of various angles covering A, B, E, and F are determined at once. According to the method of the present invention, it is possible to reduce the artifact (artifact) caused by the error of the diagonal detection, and to significantly reduce the complexity compared to the existing method.

The first interpolator 230 receiving the interpolation direction from the interpolation direction determiner 220 spatially interpolates the input pixel using a predetermined spatial filter according to the interpolation direction (S330).

FIG. 6 is a pixel layout view illustrating a method of performing spatial filtering using only information of a current input field according to the determined interpolation direction. When obtaining the X value to be interpolated, the first interpolator 230 uses a 2tab filter having a low pass filter in the diagonal direction and a 6tab filter having a high pass filter in the vertical direction. Specific interpolation methods for interpolating using spatial filters are described in Equations 4 to 6 below.

X = (C + D) >> 1

X = (A + F) >> 1

X = (20 * (B + E)-5 * (H + I) + G + J) >> 5,

In Equations 4 to 6, the values A to J are values of the pixel illustrated in FIG. 6, the operator >> is a shift operator, and the x >> y function is a function of dividing the x value by 2 ^y .

The first interpolator 230 calculates an X value by Equation 4 when the interpolation direction input from the interpolation direction determiner 220 is a first diagonal direction (upper left and lower right directions), and the interpolation direction is set to zero. 2 In the diagonal direction (upper left and lower right), calculate the X value by the equation (5). In addition, when the interpolation direction is vertical, the value of the pixel X to be interpolated is calculated according to Equation 6, which is filtered by 6 tabs.

In the present invention, unlike the general method of using a high pass filter that uses the diagonal direction when there is an oblique edge, in order to eliminate the zigzag phenomenon, a smoothing effect is achieved by using a low pass filter, a 2 tab filter, and a high pass in the remaining areas. The high frequency component was saved by using a 6 tab filter as a filter.

On the other hand, the second interpolator 240 that receives the spatially interpolated input pixel value from the first interpolator 230 compares the vert value calculated by Equation 2 with a predetermined threshold value T3. It is determined whether a vertical high frequency component exists in the spatially interpolated input pixel (S340). The second interpolator 240 determines that there is a vertical high frequency component when the vert value is larger than the threshold value T3, and determines that there is no small value.

If there is a vertical high frequency component, it is an edge in the horizontal direction, and to compensate for the problem that flickering occurs because the value of the previous field and the current field are clearly different, the spatially interpolated pixel using temporal information Reset the value. To this end, the second interpolator 240 resets the pixel value by using Equation 7 below (S350).

X ’= (10 * X + 3 * h + 3 * k) >> 4

The present invention performs steps S310 to S350 on all the pixels to be interpolated of the input field image, converts the input field image into a sequential image, and the output unit 250 outputs the converted sequential image. (S360).

Examples of converting an 720 * 240 interlaced image into a 720 * 480 sequential image are shown in FIGS. 7A to 7B and 8A to 8C, respectively.

7A is an interlaced input image, FIG. 7B is a sequential image converted by the present invention, and FIG. 7C is a sequential image converted by the prior art. In the case of FIG. 7C, the zigzag phenomenon appears in the right arm part and the left shoulder part of the person, but the phenomenon is alleviated in FIG. 7B according to the present invention. In addition, in the case of FIG. 7C, although the line of the table tennis table looks crushed, it can be seen that the phenomenon is alleviated in FIG. 7B according to the present invention.

Similarly, FIG. 8A illustrates an interlaced input image, FIG. 8B illustrates a sequential image converted by the present invention, and FIG. 8C illustrates a sequential image converted by the prior art. It can be seen that the zigzag phenomenon appears in the oblique portions of the letters shown in Figure 8c, the zigzag phenomenon can be seen in Figure 8b.

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, which are also implemented in the form of a carrier wave (for example, transmission over the Internet). It also includes. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

According to the present invention, interpolation is performed on the moving part as described above, and the interpolated scanned image is adaptively reduced while the damage of the original image is adaptively applied to the moving part by using the pixel value of the previous field as it is. There is an effect that can be converted into a sequentially scanned image.

  In particular, there is an effect of reducing noise by reducing the possibility of false direction determination at the time of pixel direction determination. In addition, there is an effect that can detect the oblique portion using a simple algorithm when determining the direction.

Claims (27)

A method of interpolating interlaced field images and converting them into progressively scanned frame images, (a) detecting a motion of a pixel to be interpolated of the input field image by using preceding field images and trailing field images; (b) when the motion is detected, determining an interpolation direction of the pixel to be interpolated using pixel values on another scan line; (c) spatially interpolating the pixels to be interpolated using a predetermined filter along the interpolation direction; And (d) resetting the value of the pixel to be interpolated by using corresponding pixel values of a preceding field and a trailing field and the spatially interpolated pixel value when a vertical high frequency component exists in the pixel to be interpolated; Method for converting interlaced scan image to a sequential image, characterized in that. The method of claim 1, wherein step (a) And detecting a motion using a difference between the pixels of the preceding field images and the following field images corresponding to adjacent pixels of the pixel to be interpolated. The method of claim 1, wherein step (a) The difference between the pixels of the preceding field image and the pixels of the following field image corresponding to the first pixel to be interpolated and adjacent second pixels on the same scan line as the first pixel, and upper and lower sides adjacent to the first pixel Detecting the movement by using a difference between the third pixels on the scan line and the pixels of the preceding field image corresponding to the third pixels, and a difference between the pixels of the trailing field image corresponding to the third pixels. A method for converting an interlaced scan image into a sequential image. The method of claim 3, wherein the difference between the pixels is The absolute value of the difference between the values of the pixels, and if the sum of the absolute value is greater than a predetermined threshold value, characterized in that the movement is determined. The method of claim 1, wherein step (a) If it is determined that there is no movement of the pixel to be interpolated, setting the pixel value of the preceding field image corresponding to the pixel to be interpolated as the pixel value of the pixel to be interpolated and interpolating the pixel to be interpolated. Method for converting interlaced scan image to a sequential image, characterized in that. The method of claim 1, wherein step (b) When the difference between the pixel value on the upper scan line corresponding to the pixel to be interpolated and the pixel value on the lower scan line is less than a predetermined threshold value, the interpolation direction of the interpolated scan image is determined in the vertical direction. How to convert to video. The method of claim 1, wherein step (b) If the difference between the pixel value on the upper scan line corresponding to the pixel to be interpolated and the pixel value on the lower scan line is greater than or equal to a predetermined threshold value, the interpolation direction of the interpolation scan image is determined in an oblique direction. How to convert to video. 8. The method of claim 7, wherein step (b) The interlaced scanning image is determined as a sequential image, wherein the interpolation direction is determined in a direction in which the difference between the predetermined number of pixel values on the upper scan line adjacent to the pixel to be interpolated and the predetermined number of pixel values on the lower scan line is minimized. How to convert. The method of claim 1, wherein step (b) (b1) obtaining a first difference value between pixels located in an upper scan line and a lower scan line in a first oblique direction around the pixel to be interpolated; (b2) obtaining a second difference value between pixels located in an upper scan line and a lower scan line in a second oblique direction in the input field image centering on the pixel to be interpolated; (b3) obtaining a third difference value between the first difference value and the second difference value and comparing it with a predetermined threshold value; And (b4) determining the interpolation direction in a direction corresponding to a smaller difference value between the first difference value and the second difference value when the third difference value is larger than the threshold value. How to convert interlaced images into sequential images. The method of claim 1, wherein step (c) And interpolating the pixel using a six-tap filter when the interpolation direction is vertical. The method of claim 1, wherein step (c) And interpolating the pixel using a 2-tap filter along the diagonal direction when the interpolation direction is not the vertical direction. The method of claim 1, wherein step (d) The result of multiplying the spatially interpolated pixel value by a predetermined first weight, multiplying the corresponding pixel value of the preceding field and the corresponding pixel value of the preceding field by a predetermined second weight, and dividing the result by a predetermined constant divides the value of the pixel. A method for converting an interlaced image into a sequential image, characterized by resetting. The interlace of claim 1, wherein the preceding field images are two field images that temporally precede the input field image, and the trailing field images are two field images that temporally follow the input field image. A method of converting a scanned image into a sequential image. A recording medium recorded with executable program code that can be read by a computer and converting the interlaced image of any one of claims 1 to 13 into a sequential image. An apparatus for interpolating interlaced field images and converting them into progressively scanned frame images, A motion detector for detecting a motion of a pixel to be interpolated of the input field image by using preceding field images and trailing field images; An interpolation direction determiner which determines an interpolation direction of the pixel to be interpolated from which motion is detected using pixel values on another scan line; A first interpolation unit for spatially interpolating the pixels to be interpolated using a predetermined filter along the interpolation direction; And A second interpolation unit for resetting a value of the pixel to be interpolated by using corresponding pixel values of a preceding field and a subsequent field and the spatially interpolated pixel value when a vertical high frequency component exists in the pixel to be interpolated; The apparatus for converting interlaced scan image to a sequential image, characterized in that. The method of claim 15, wherein the motion detector And detecting motion using a difference between pixels of the preceding field images and the following field images corresponding to adjacent pixels of the pixel to be interpolated. The method of claim 15, wherein the motion detector The difference between the pixels of the preceding field image and the pixels of the following field image corresponding to the first pixel to be interpolated and adjacent second pixels on the same scan line as the first pixel, and upper and lower sides adjacent to the first pixel Detecting the movement by using a difference between the third pixels on the scan line and the pixels of the preceding field image corresponding to the third pixels, and a difference between the pixels of the trailing field image corresponding to the third pixels. A device for converting an interlaced image into a sequential image. 18. The method of claim 17, wherein the difference between the pixels is And an absolute value of a difference between the values of the pixels, and when the sum of the absolute values is greater than a predetermined threshold value, determining that there is a motion. The method of claim 15, And a third interpolation unit configured to interpolate the pixel to be interpolated by setting a pixel value of the preceding field image corresponding to the pixel to be interpolated as the pixel value of the pixel to be interpolated with respect to the pixel to be interpolated. Device for converting interlaced scan image to a sequential image, characterized in that. The method of claim 15, wherein the interpolation direction determiner When the difference between the pixel value on the upper scan line corresponding to the pixel to be interpolated and the pixel value on the lower scan line is less than a predetermined threshold value, the interpolation direction of the interpolated scan image is determined in the vertical direction. Device to convert to video. The method of claim 15, wherein the interpolation direction determiner If the difference between the pixel value on the upper scan line corresponding to the pixel to be interpolated and the pixel value on the lower scan line is greater than or equal to a predetermined threshold value, the interpolation direction of the interpolation scan image is determined in an oblique direction. Device to convert to video. The method of claim 21, wherein the interpolation direction determiner The interlaced scanning image is determined as a sequential image, wherein the interpolation direction is determined in a direction in which the difference between the predetermined number of pixel values on the upper scan line adjacent to the pixel to be interpolated and the predetermined number of pixel values on the lower scan line is minimized. Device to convert. The method of claim 15, wherein the interpolation direction determiner A first difference calculator configured to calculate a first difference value between pixels located in an upper scan line and a lower scan line in a first oblique direction around the pixel to be interpolated; A second difference calculator configured to calculate a second difference value between pixels located in an upper scan line and a lower scan line in a second oblique direction in the input field image based on the pixel to be interpolated; The third difference value between the first difference value and the second difference value is obtained, and when the third difference value is larger than a predetermined threshold value, the third difference value corresponds to the smaller difference value among the first difference value and the second difference value. And an orientation determiner configured to determine the interpolation direction in a direction. The method of claim 15, wherein the first interpolation unit And interlacing the pixel using a six-tap filter when the interpolation direction is a vertical direction. The method of claim 15, wherein the first interpolation unit And interlacing the pixel using a 2-tap filter along the diagonal direction when the interpolation direction is an oblique direction. The method of claim 15, wherein the second interpolation unit The result of multiplying the spatially interpolated pixel value by a predetermined first weight, multiplying the corresponding pixel value of the preceding field and the corresponding pixel value of the preceding field by a predetermined second weight, and dividing the result by a predetermined constant divides the value of the pixel. An apparatus for converting an interlaced image into a sequential image, characterized in that for resetting. The interlace of claim 15, wherein the preceding field images are two field images that temporally precede the input field image, and the trailing field images are two field images that temporally follow the input field image. A device for converting a scanned image into a sequential image.

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