JP2009177524A - Scanning line interpolating device and scanning line interpolating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scanning line interpolating device and method which leave an improvement effect of an oblique interpolation, and reduce an image quality deterioration near a still image such as a caption, etc. of image quality deteriorations as an abuse of oblique interpolation processing. <P>SOLUTION: A first retarding means 12 retards an input video signal by one frame, a still determining means 13 inputs the input video signal and an output of the first retarding means to determine whether a pixel is still, a still continuity determining means 14 inputs an output of the still determining means and an output of a third retarding means to determine a temporal direction continuity of a still state of the pixel, a second retarding means 15 and the third retarding means 16 retard an output of the still continuity determining means by one field and further retard it by one field, an interpolative direction determining means 17 inputs the output of the still continuity determining means and an output of the second retarding means to determine a generating direction of a deterioration by an oblique interpolation, and an interpolating means 18 excludes a direction of the image quality deterioration from interpolative direction choices to carry out the oblique interpolation processing to generate an interpolative line signal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a scanning line interpolation apparatus and a scanning line interpolation method for generating an interpolation line by performing oblique interpolation processing when, for example, converting an interlaced scanning image into a sequential scanning image.

  In general, when an interlaced image (hereinafter referred to as an interlaced) image is converted into a progressively scanned (hereinafter referred to as a progressive) image, when the interlaced image is a still image, one field scan line is connected to the other Inter-field interpolation is performed to generate an interpolated scan line (hereinafter referred to as an interpolated line) by interpolating between the field scan lines, and when the interlaced image is a moving image, the interlaced image on the adjacent scan line in the same field. Intra-field interpolation is performed to generate an interpolation line using pixels.

  When generating an interpolated line between interlaced n lines and interlaced n + 1 lines in the interpolation process in the field, the pixels U and D on the upper and lower scanning lines n and n + 1 are added and averaged as the pixel A on the interpolated line. The method of obtaining the value (= (U + D) / 2) is simple. However, when this vertical interpolation method is applied, depending on the pattern, an oblique line may appear jagged, so-called jaggy is noticeable.

As a technique for converting an interlaced image into a progressive image, there is a motion adaptive progressive conversion. This technique is a technique in which motion detection is performed in units of pixels or pixel blocks, and the inter-field interpolation processing result and inter-field interpolation processing result are mixed with a mixing ratio corresponding to the motion detection result. As motion detection, estimation is performed from a difference in signal level between pixels at the same position in one frame.
However, in the motion adaptive progressive conversion processing, if the upper and lower pixel average values are used as the intra-field interpolation processing, the vertical resolution is lowered, and there is a problem that the diagonal lines appear jagged.

On the other hand, as a method for solving such a problem, a method called diagonal interpolation is known.
In the oblique interpolation process, when generating the interpolation pixel A, a pair of pixels that are point-symmetric with respect to the pixel A on the interpolation line is selected from the upper and lower scanning lines n and n + 1, and the average value is selected. This is a method used as an interpolated pixel value.

  As an example of the method of selecting the interpolation direction, there is a method of using the one having the smallest absolute difference value between a pair of pixels. For example, the difference between a pair of pixels in the vertical and diagonal directions centered on the pixel to be interpolated is taken, a large diagonal correlation signal is used to determine the direction with high diagonal correlation, and an interpolation pixel is created. is there.

  As a prior art according to the applicant's application relating to oblique interpolation, there is one described in Patent Document 1. In Patent Literature 1, information for estimating the contour of a pattern of input image data is calculated, and the output of the contour information is compared with a positive threshold value and a negative threshold value to be ternarized. Using the data, an interpolation direction candidate for generating an interpolation line is selected, and a final interpolation direction is determined from the selected interpolation direction candidate. The input image data is subjected to interpolation processing using pixels in the determined interpolation direction to generate an interpolation line. According to this method, by first detecting the contour of the interlaced image, the interpolation pixel A is generated on the interpolation line using the appropriate pixels U and D along the contour line on the upper and lower lines n and n + 1. Therefore, it is possible to prevent an error in generating the interpolation pixel A by ignoring the outline of the pattern.

However, this technique increases the visual resolution in the vertical direction, but it has been found that image quality deterioration due to erroneous determination in determining the interpolation direction can occur as a negative effect. For example, when image data in which a graphic still image (for example, still characters) is superimposed on a moving image is supplied as input, the jagged feeling of the diagonal lines of the moving image on the back is improved, but diagonal interpolation processing is performed around the still character. Degradation of image quality due to the harmful effects of This is a portion of a stationary character placed on a background video that is bolded or surrounded by a line, or a recessed space formed between a stationary character and a background object portion that is adjacent or overlapped with the stationary character. In addition, since the interpolation pixels are formed using the pixels of the stationary character so as to follow the contour of the stationary character itself or the pseudo contour line of the stationary character and the background image adjacent thereto, This is due to the fact that the bolded or encircled part is interpolated with pixels similar to a stationary character and the shape of the original stationary character is impaired.
JP 2007-142669 A

  In view of the above-described problems, the present invention leaves an improvement effect of diagonal interpolation while interpolating by inputting an interlaced image in which a still image such as subtitles is superimposed in a moving image, and performing the diagonal interpolation processing. An object of the present invention is to provide a scanning line interpolation apparatus and a scanning line interpolation method capable of reducing image quality deterioration in the vicinity of a still image among image quality deterioration as a negative effect.

  According to one aspect of the present invention, first delay means for delaying an input video signal by one frame, and whether or not a pixel is stationary by using the input video signal and the output of the first delay means as inputs A stationary continuity determining unit, a stationary continuity determining unit that determines the temporal continuity of a stationary state of a pixel by using the output of the stationary determination unit and the output of the third delay unit as inputs. A second delay means for delaying the output by one field; a third delay means for delaying the output of the second delay means by one field; an output of the static continuity determining means and the second delay; Interpolation direction determination means for determining a direction in which there is a possibility of deterioration due to oblique interpolation, with the output of the means as input, and by interpolating the interpolation direction determined by the interpolation direction determination means from the choice of interpolation directions A scanning line interpolation device comprising: an interpolation processing means for generating an interpolation line by performing processing is provided.

  According to another aspect of the present invention, the input video signal is delayed by one frame, and the input video signal and the video signal delayed by one frame are input to the stillness determining means, and the pixel is stationary at around one frame. And whether the stationary determination result and the determination output obtained by delaying the determination output of the stationary continuity determining unit by one frame are input to the stationary continuity determining unit, and the temporal continuity of the still state of the pixel is determined. The static continuity determination output of the static continuity determination means is delayed by one field, further delayed by one field, and the static continuity determination output delayed by two fields is supplied to the static continuity determination means. The static continuity determination output of the static continuity determination means and the static continuity determination output delayed by one field are input to the interpolation direction determination means, and there is a risk of deterioration due to oblique interpolation. Interpolation processing is performed by determining the interpolation direction and performing the diagonal interpolation process by excluding the interpolated direction determined by the interpolation direction determination means from the interpolation direction options in the interpolation processing means for executing the diagonal interpolation process. A scanning line interpolation method is provided that is characterized by generating.

  According to the present invention, when an interlaced image in which a still image such as subtitles is superimposed on a moving image is input and interpolated, the improvement effect of the diagonal interpolation is left and the adverse effect of the diagonal interpolation processing is It is possible to provide a scanning line interpolation apparatus and a scanning line interpolation method that can reduce the deterioration in image quality in the vicinity of a still image among image quality deteriorations.

Prior to describing embodiments of the present invention with reference to FIGS. 1 to 6, related techniques of the present invention will be described with reference to FIGS. 7 to 11.
As a technique for converting an interlaced image to a progressive image, a motion adaptive progressive conversion technique that is generally used performs motion detection in units of pixels or pixel blocks, and results of intra-field interpolation processing and inter-field interpolation processing Are mixed at a mixing ratio corresponding to the motion detection result.

  FIG. 7 shows an example of motion adaptive IP (interlace / progressive) conversion. In FIG. 7, one frame of an interlaced image is composed of a top field (also referred to as a first field, abbreviated as top) and a bottom field (also referred to as a second field, abbreviated as bottom). As regards the three fields A, B, and C, the time A is input every time one field period (1V or simply referred to as one field) passes in the order of the fields A, B, and C. Therefore, the field A and the field C have a time difference of 2 field periods (same as 1 frame period, 2V or simply 2 fields).

Now, as shown in FIG. 7, when generating the value of the pixel b of the interpolation line (indicated by the dotted line) between the scanning lines adjacent to the upper and lower sides of the field B (indicated by the solid line),
Inter-field interpolation result (for example, average value of pixel a in field A and pixel c in field C)
Inter-field interpolation result (for example, average value of upper and lower pixels bu and bd of field B)
These two types of interpolation pixels are mixed according to the amount of motion at the position of the pixel b. Here, the amount of motion is estimated from the difference between the pixel a and the pixel c, for example.

  In the above-mentioned motion adaptive progressive conversion processing, if the upper and lower pixel average values (average values of bu and bd in the example of FIG. 7) are used as the intra-field interpolation processing, the resolution in the vertical direction becomes low and the diagonal lines become jagged. There is a problem to see.

As a countermeasure, there is a technique called diagonal interpolation.
Although the prior art of oblique interpolation (Patent Document 1) increases the apparent resolution in the vertical direction, image quality deterioration due to misjudgment in determining the interpolation direction can occur as an adverse effect. As an example, a simulation image showing the effect of diagonal interpolation and its adverse effects is shown below. Here, as an example of an interlaced image that may cause such image quality degradation, a case where an interlaced image in which a graphic image (still image) such as a still character is superimposed on a natural image (for example, a moving image) on the back is input will be described. .

  For comparison, FIG. 8 shows an example of the intra-field interpolation result when diagonal interpolation is not performed (only vertical interpolation), and FIG. 9 shows an example of the intra-field interpolation result when diagonal interpolation is performed. . FIG. 10 shows an enlarged main image quality degradation portion in FIG.

  When the diagonal interpolation of FIG. 9 is performed, the jagged feeling of the diagonal lines of the natural image on the back is improved as compared with the case where the diagonal interpolation of FIG. 8 is not performed, but as shown in FIGS. Image quality degradation due to the negative effects of diagonal interpolation processing is seen in the vicinity of the stationary characters (circled).

  In Patent Document 1, as shown in FIG. 11, an interlaced image has a portion with a small pixel value and a portion with a large pixel value (for example, a black portion and a white portion), and the boundary between the two portions is an outline. In order to generate the interpolation pixel A in the vicinity of the contour in the interpolation line generated between the interlace n line and the interlace n + 1 line, first, the contour of the interlaced image is detected, and the oblique direction along the detected contour Is selected as the interpolation direction, and for each pixel U, D on the n, n + 1 line corresponding to that direction, that is, for the pixel U on the n line and the pixel D on the n + 1 line, the average value of the sum of both pixels is calculated. The calculated value is output (generated) as the pixel value of the interpolation pixel A. However, image quality degradation as shown in FIGS. 9 and 10 occurs when an interlaced image in which a graphic image (still image) such as a still character is superimposed on a natural image (for example, a moving image) on the back is input. This is because the pixel of the graphic image is used instead of the pixel used for the position of the background moving image on the erroneous interpolation direction during the interpolation process in order to detect the contour direction in error.

  Therefore, in the embodiment of the present invention, when oblique interpolation processing is used to convert an interlaced image to a progressive image, image quality degradation in the vicinity of still images such as subtitles may occur as a harmful effect, but this image quality degradation is reduced. In addition, a long-time stationary state determination process is performed for each pixel, and a pixel that is not in a long-time stationary state is not used to generate an interpolation pixel at a position that is not in a stationary state for a long time (that is, a position that is determined as a moving image). Is.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a scanning line interpolation apparatus according to an embodiment of the present invention.
The scanning line interpolation apparatus 10 shown in FIG. 1 includes an input terminal 11, a first delay unit 12, a stationary determination unit 13, a stationary continuity determination unit 14, a second delay unit 15, and a third delay. Means 16, interpolation direction determination means 17, interpolation processing means 18, and output terminal 19 are provided.

An interlace video signal is input to the input terminal 11. The first delay means 12 includes a 2V delay unit that delays the video signal input from the input terminal 11 by one frame. The stillness determination means 13 inputs two video signals, the currently input video signal and the video signal delayed by one frame from the first delay means 12, and determines whether or not the pixel is still.
Since the two video signals input to the stillness determination means 13 have a time difference corresponding to two field periods, the stillness determination means 13 is simultaneously input with the video signals of the top fields or the bottom fields.

The stationary continuity determining unit 14 determines the temporal continuity of a pixel in a stationary state using the determination output of the stationary determining unit 13 and a delay output from a third delay unit 16 described later as inputs. The second delay means 15 is composed of a 1V delay section that delays the output of the static continuity determination means 14 by one field. The third delay means 16 is composed of a 1V delay section that delays the output of the second delay means 15 by one field.
Since the two stillness determination outputs input to the stillness continuity determination means 14 have a time difference corresponding to two field periods, the stillness determination outputs for the top fields or the bottom fields are simultaneously input to the stillness continuity determination means 14. It will be.

The interpolation direction determination means 17 receives the output of the static continuity determination means 14 and the delay output of the second delay means 15 as inputs, in a direction in which degradation may occur due to diagonal interpolation (in other words, an interpolation direction candidate for diagonal interpolation). (Interpolation direction to be excluded).
Since the two static continuity determination outputs input to the interpolation direction determination means 17 have a time difference corresponding to one field period, either one of the two static continuity determination outputs is the top field. In the other, the bottom field static continuity determination output is input simultaneously.

  The interpolation processing unit 18 excludes the interpolation direction determined by the interpolation direction determination unit 17 from a plurality of choices of interpolation direction candidates, and generates an interpolation line signal by performing diagonal interpolation processing. The output terminal 19 outputs the interpolation line signal from the interpolation processing means 18.

  In addition, by adopting a configuration in which the line selection means is provided at the subsequent stage of the output terminal 19, the interpolation line signal from the output terminal 19 is supplied to one input terminal of the line selection means (not shown) and the other of the line selection means is supplied. The video signal for one horizontal line input from the input terminal 11 is supplied to the input terminal of the input terminal, and the current input video signal and the interpolation line signal are alternately switched for each horizontal line and output. A progressive video signal in which lines are vertically interpolated can be output.

FIG. 2 shows a configuration example of the stillness determination means 13.
The stillness determination means 13 shown in FIG. 2 includes a subtraction means 21 that takes the difference between the input video signal from the input terminal 11 and the output from the first delay means 12, and an absolute value that takes the absolute value of the difference from the subtraction means 21. A value determination unit 22 and a comparison determination unit 23 that compares the absolute difference value from the absolute value conversion unit 22 with a threshold value, determines that the difference absolute value is equal to or less than the threshold value, and determines that the moving image is larger than the threshold value. I have.

  In such a configuration, the stillness determination unit 13 compares the absolute difference between the input video signal and the output of the first delay unit 12 with a threshold value for each pixel, and determines whether the stillness determination result is “0” or “1”. Is output in binary. If the output of the stationary determination means 13 is “0”, it means “moving”, and if it is “1”, it means “still”. Here, if the threshold is set to “0”, it is determined as “still” only in the completely stationary state (that is, the difference absolute value = 0), and the determination result “1” is output. The determination result “0” is output.

FIG. 3 shows a configuration example of the stationary continuity determination means 14.
3 receives the output of the stillness determination means 13 and the output of the third delay means 16, and outputs the output delayed by two fields from the third delay means 16 (= 1 frame). For example, a multi-bit counter that counts up each time (delay output) is input, and the count value of the counter is output as a still continuity determination result indicating the length of the still state. The stationary continuity determining unit 14 counts up if the input from the stationary determining unit 13 is a determination result of “still”, and is reset to 0 otherwise. And when the result reaches a certain limit value, it can be realized by a method of performing saturation processing. More specifically, (1) if the input from the stillness determination means 13 is the determination result that the moving image is “0”, 0 is output as the count value of the counter, and (2) the third delay instead. When the output of the means 16 reaches the limit value of the counter (abbreviated as LIMIT, here the upper limit value), the limit value is held and output, and the two conditions (1), (3) If it does not correspond to 2), the counter counts up (count ⁺⁺ ) and the count value is output. The three conditions (1) to (3) are: (1) has the highest priority, (3) has the lowest priority, (2) has an intermediate priority between (1) and (3) It has become.

  In such a configuration, the static continuity determination unit 14 can output a value having some temporal width. That is, it is possible to output the length of the stationary state as to how long it is stationary as the count value. If the count value is, for example, an 8-bit counter, the limit value is 256. The determination as to whether or not this value should be in a stationary state is shown in the flowchart of FIG. Judge by threshold THT. If the count value of the counter is larger than the threshold value THT, it is determined that the pixel is a still image. Note that if the threshold value THT in FIG. 5 is set to 30, for example, the counter counts 30 times. In other words, the state in which the pixel stillness determination output continues 30 times during the period until the 1-frame delay output is input (that is, 1 It is equivalent to a state of being stationary for a second).

  The output of the static continuity determination means 14 is input to the interpolation direction determination means 17 together with the output of the second delay means 15 that delays the output by one field period.

  In the present embodiment, as illustrated in FIG. 4, the number of horizontal taps for determining an interpolation direction option for oblique interpolation will be described as 5 taps, for example. At this time, there are five interpolation directions, direction 0 to direction 4, as shown in FIG. Static continuity judgment result for upper line used for interpolation is U0 to U4, stationary continuity judgment result for lower line used for interpolation is D0 to D4, and static continuity judgment at interpolation output position (shown with a hatched circle) The result is OUT. These still continuity determination results all correspond to the count value of the counter of the still continuity determination means 14.

  At this time, the interpolation direction determination means 17 determines that the interpolation output position is a moving image if the stillness continuity determination result OUT at the interpolation output position does not exceed the threshold value THT (when it exceeds this threshold value, the interpolation direction). The directions that can be used as candidates for the pair are the directions in which the pair of U0 to U4 and D0 to D4 does not exceed the threshold value THT, and at least one of the pair of U0 to U4 and D0 to D4 exceeds the threshold value THT If so, the direction of the pair including the pixel is excluded from the interpolation direction candidates. This will be specifically described with reference to the flowchart of FIG.

FIG. 5 shows a flowchart as a specific example of the interpolation direction determination in the interpolation direction determination means 17.
In FIG. 5, the interpolation direction determination means 17 is based on two static continuity determination results for the top field and the bottom field that are simultaneously input from the output of the static continuity determination means 14 and the output of the second delay means 15. The interpolated output position in the bottom field corresponding to the static continuity determination results U0 to U4 and D0 to D4 for the pixels on the top and bottom two horizontal lines in the top field and the top and bottom two horizontal lines in the top field. The static continuity determination result OUT for the pixels of is obtained.

  First, the still continuity determination result OUT for the pixel at the interpolation output position is compared with a threshold value THT for determining whether or not the image is a still image (step S1). If the still continuity determination result OUT is greater than the threshold value THT, the interpolation output position is determined. If it is a still image, nothing is done (that is, the interpolation output position is a still part in the graphic and there are no interpolation direction candidates to be excluded), and if the still continuity determination result OUT is less than the threshold value THT, the interpolation output position Is determined to be a moving image, and the process proceeds to the next step S2.

  In step S2, if the interpolation output position is determined to be a moving image and the still continuity determination result U0 or D4 of the pixel on one of the upper and lower horizontal lines is greater than the threshold value THT. Assuming that the pixel position of U0 or D4 is a still image, the interpolation direction 0 connecting the pixel position and the interpolation output position is supplied to the interpolation processing means 18 as information to be excluded from the diagonal interpolation direction candidates (step S3). The process proceeds to step S4. If the still continuity determination result U0 or D4 of the pixels on the horizontal line is equal to or smaller than the threshold value THT in step S2, it is determined that the pixel position of U0 or D4 is a moving image, and the process proceeds to the next step S4.

  In step S4, if the still continuity determination result U1 or D3 of the pixel on one of the upper and lower horizontal lines is greater than the threshold value THT, the pixel position of U1 or D3 is determined to be a still image, and the pixel Interpolation direction 1 connecting the position and the interpolation output position is supplied to the interpolation processing means 18 as information to be excluded from the diagonal interpolation direction candidates (step S5), and the process proceeds to the next step S6. If the still continuity determination result U1 or D3 of the pixel on the horizontal line is equal to or smaller than the threshold value THT in step S4, the pixel position of U1 or D3 is determined to be a moving image, and the process proceeds to the next step S6.

  In step S6, if the static continuity determination result U3 or D1 of a pixel on one of the upper and lower horizontal lines is larger than the threshold value THT, the pixel position of U3 or D1 is determined to be a still image, and the pixel Interpolation direction 3 connecting the position and the interpolation output position is supplied to the interpolation processing means 18 as information to be excluded from the diagonal interpolation direction candidates (step S7), and the process proceeds to the next step S8. In step S6, if the still continuity determination result U3 or D1 of the pixel on the horizontal line is equal to or less than the threshold value THT, it is determined that the pixel position of U3 or D1 is a moving image, and the process proceeds to the next step S8.

  In step S8, if the still continuity determination result U4 or D0 of a pixel on one of the upper and lower horizontal lines is greater than the threshold value THT, the pixel position of U4 or D0 is determined to be a still image, and the pixel Interpolation direction 4 that connects the position and the interpolation output position is supplied to the interpolation processing means 18 as information to be excluded from the oblique interpolation direction candidates (step S9), and the process ends. If the still continuity determination result U4 or D0 of the pixel on the horizontal line is equal to or smaller than the threshold value THT in step S8, the process ends, assuming that the pixel position of U4 or D0 is a moving image.

Then, the output of the interpolation direction determination means 17 is input to the interpolation processing means 18.
The interpolation processing means 18 is composed of, for example, a device 100, 100A or 100B as shown in FIG. 1, FIG. 25 or FIG. 26 of Patent Document 1 (Japanese Patent Laid-Open No. 2007-142669). From the interpolation direction options (interpolation direction candidates) output from the first pattern comparison unit 151 and the second pattern comparison unit 152, or the first pattern comparison unit 251 and the second pattern comparison unit 252). By performing the diagonal interpolation process by excluding the interpolation direction determined by the interpolation direction determination unit 17 of FIG. 1, it is possible to select the correct interpolation direction that does not cause image quality degradation and generate an interpolation line signal. The interpolation processing means 18 is not limited to the configuration of Patent Document 1, and has an algorithm that estimates a plurality of interpolation directions for oblique interpolation and finally determines one interpolation direction from them. If applicable, it is widely applicable.

FIG. 6 shows a simulation result obtained in this embodiment.
Even when image data in which a graphic still image is superimposed on a moving image is input, it is possible to prevent image quality degradation as shown in FIGS. 9 and 10 appearing in the vicinity of a still pixel from occurring.

  According to the embodiment of the present invention, when performing the interpolation processing of the scanning line using the diagonal interpolation processing, the pixels in the stationary state for a long time are detected, and the result is used for selecting the interpolation direction. While leaving the improvement effect, among the image quality deterioration as the adverse effect of the diagonal interpolation process, the image quality deterioration in the vicinity of the long-time still pixel, which is an adverse effect of the diagonal interpolation, can be reduced.

1 is a block diagram showing a scanning line interpolation apparatus according to an embodiment of the present invention. The block diagram which shows the structural example of the stillness determination means in this embodiment. The block diagram which shows the structural example of the static continuity determination means in this embodiment. Explanatory drawing which shows the interpolation direction of the diagonal interpolation in this embodiment. The flowchart explaining the specific example of the interpolation direction determination means in this embodiment. The figure which shows the simulation result of this invention. 7 to 11 show related techniques of the present invention, and FIG. 7 shows an example of motion adaptive IP conversion and an example of motion adaptive IP conversion. Explanatory drawing which shows the example of the interpolation result in a field when interpolation is not performed (only up-and-down interpolation). Explanatory drawing which shows the example of the interpolation result in the field in the case of performing diagonal interpolation. The enlarged view which expands and shows the main image quality degradation part in FIG. The figure explaining the prior art (patent document 1) of diagonal interpolation.

Explanation of symbols

10. Scanning line interpolation device
DESCRIPTION OF SYMBOLS 12 ... 1st delay means 13 ... Stillness determination means 14 ... Stillness continuity determination means 15 ... 2nd delay means 16 ... 3rd delay means 17 ... Interpolation direction determination means 18 ... Interpolation line generation means 21 ... Subtraction means 22 ... Absolute value means 23 ... Comparison determination means

Claims (5)

First delay means for delaying the input video signal by one frame;
Stillness determination means for determining whether a pixel is stationary with the input video signal and the output of the first delay means as inputs,
Stillness continuity determining means for determining the temporal continuity of the stationary state of a pixel by using the output of the stillness determining means and the output of the third delay means as inputs,
Second delay means for delaying the output of the static continuity determination means by one field;
The third delay means for delaying the output of the second delay means by one field;
Interpolation direction determination means for determining the direction in which deterioration may occur due to oblique interpolation, using the output of the static continuity determination means and the output of the second delay means as inputs.
Interpolation processing means for generating an interpolation line signal by performing an oblique interpolation process by excluding the interpolation direction determined by the interpolation direction determination means from choices of interpolation directions;
A scanning line interpolation apparatus comprising: The stationary determination means includes
Subtracting means for taking a difference between the input video signal and the output of the first delay means;
Absolute value taking means for taking the absolute value of the difference from the subtracting means;
A comparison determination unit that compares a difference absolute value from the absolute value conversion unit with a threshold value, and determines that the difference absolute value is equal to or less than a threshold value and is a still image;
The scanning line interpolation apparatus according to claim 1, further comprising: The stationary continuity determination means includes
A counter that counts up each time an output delayed by two fields from the third delay means is input, and outputs the output of the stationary determination means and the output of the third delay means; If the value is output as a stillness continuity determination result indicating the length of the still state, and the input from the stillness determination means is a determination result that is a moving image, 0 is output as the count value of the counter. Instead, when the output of the third delay means reaches the limit value of the counter, the limit value is held and output, and when the above two conditions are not met, the counter counts up and the count value The scanning line interpolating apparatus according to claim 1, wherein: The interpolation direction determining means includes
Based on two static continuity determination results for each of the top field and the bottom field, which are simultaneously input from the output of the static continuity determination unit and the output of the second delay unit, two horizontal lines in the top field Obtain a still continuity determination result for the upper pixel and a still continuity determination result for the pixel at the interpolation output position corresponding to the two horizontal lines above and below the top field in the bottom field. Compare the static continuity determination result for the image with the threshold value for whether or not it is still, and if the static continuity determination result is greater than the threshold value, the interpolation output position is determined to be a still image, and the static continuity determination result If the interpolation output position is determined to be a movie, the interpolation output position is determined to be a movie. If the stationary continuity determination result of a pixel on one horizontal line of a flat line is larger than the threshold value, the interpolation processing is performed as information for excluding the interpolation direction connecting the position of the pixel and the interpolation output position from the candidate for the diagonal interpolation direction. 4. The scanning line interpolating apparatus according to claim 1, wherein the scanning line interpolating apparatus is supplied to the means. Delay the input video signal by one frame,
The input video signal and the video signal delayed by one frame are input to the stillness determining means to determine whether or not the pixel is still before and after one frame,
The stillness determination result and the determination output obtained by delaying the determination output of the stillness continuity determination unit by one frame are input to the stillness continuity determination unit, and the temporal continuity of the still state of the pixel is determined.
The static continuity determination output of the static continuity determination means is delayed by one field, further delayed by one field, and the static continuity determination output delayed by two fields is supplied to the static continuity determination means,
The static continuity determination output of the static continuity determination unit and the static continuity determination output delayed by one field are input to the interpolation direction determination unit, and an interpolation direction in which degradation may occur due to oblique interpolation is determined.
The interpolation processing means for executing the diagonal interpolation processing excludes the interpolated direction determined by the interpolation direction determination means from the interpolation direction options and performs the diagonal interpolation processing to generate an interpolation line signal. Scan line interpolation method.